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Sample records for quantitative proton magnetic

  1. Determination of scutellarin in breviscapine preparations using quantitative proton nuclear magnetic resonance spectroscopy

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    Zhenzuo Jiang

    2016-04-01

    Full Text Available The objective of the present study was to develop the selection criteria of proton signals for the determination of scutellarin using quantitative nuclear magnetic resonance (qNMR, which is the main bioactive compound in breviscapine preparations for the treatment of cerebrovascular disease. The methyl singlet signal of 3-(trimethylsilylpropionic-2,2,3,3-d4 acid sodium salt was selected as the internal standard for quantification. The molar concentration of scutellarin was determined by employing different proton signals. To obtain optimum proton signals for the quantification, different combinations of proton signals were investigated according to two selection criteria: the recovery rate of qNMR method and quantitative results compared with those obtained with ultra-performance liquid chromatography. As a result, the chemical shift of H-2′ and H-6′ at δ 7.88 was demonstrated as the most suitable signal with excellent linearity range, precision, and recovery for determining scutellarin in breviscapine preparations from different manufacturers, batch numbers, and dosage forms. Hierarchical cluster analysis was employed to evaluate the determination results. The results demonstrated that the selection criteria of proton signals established in this work were reliable for the qNMR study of scutellarin in breviscapine preparations.

  2. Monitoring lactic acid production during milk fermentation by in situ quantitative proton nuclear magnetic resonance spectroscopy.

    Science.gov (United States)

    Bouteille, R; Gaudet, M; Lecanu, B; This, H

    2013-04-01

    When fermenting milk, lactic bacteria convert part of α- and β-lactoses into d- and l- lactic acids, causing a pH decrease responsible for casein coagulation. Lactic acid monitoring during fermentation is essential for the control of dairy gel textural and organoleptic properties, and is a way to evaluate strain efficiency. Currently, titrations are used to follow the quantity of acids formed during jellification of milk but they are not specific to lactic acid. An analytical method without the use of any reagent was investigated to quantify lactic acid during milk fermentation: in situ quantitative proton nuclear magnetic resonance spectroscopy. Two methods using in situ quantitative proton nuclear magnetic resonance spectroscopy were compared: (1) d- and l-lactic acids content determination, using the resonance of their methyl protons, showing an increase from 2.06 ± 0.02 to 8.16 ± 0.74 g/L during 240 min of fermentation; and (2) the determination of the α- and β-lactoses content, decreasing from 42.68 ± 0.02 to 30.76 ± 1.75 g/L for the same fermentation duration. The ratio between the molar concentrations of produced lactic acids and consumed lactoses enabled cross-validation, as the value (2.02 ± 0.18) is consistent with lactic acid bacteria metabolism.

  3. Structural and Quantitative Analysis of Three C-Glycosylflavones by Variable Temperature Proton Quantitative Nuclear Magnetic Resonance

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    Jing Liu

    2017-01-01

    Full Text Available Quantitative nuclear magnetic resonance is a powerful tool in drug analysis because of its speed, precision, and efficiency. In present study, the application of variable temperature proton quantitative nuclear magnetic resonance (VT-1H-qNMR for the calibration of three C-glycosylflavones including orientin, isoorientin, and schaftoside as reference substances was reported. Since there was conformational equilibrium due to the restricted rotation around the C(sp3-C(sp2 bond in C-glycosylflavones, the conformational behaviors were investigated by VT-NMR and verified by molecular mechanics (MM calculation. The VT-1H-qNMR method was validated including the linearity, limit of quantification, precision, and stability. The results were consistent with those obtained from mass balance approach. VT-1H-qNMR can be deployed as an effective tool in analyzing C-glycosylflavones.

  4. Structural and Quantitative Analysis of Three C-Glycosylflavones by Variable Temperature Proton Quantitative Nuclear Magnetic Resonance

    Science.gov (United States)

    Liu, Yang; Dai, Zhong

    2017-01-01

    Quantitative nuclear magnetic resonance is a powerful tool in drug analysis because of its speed, precision, and efficiency. In present study, the application of variable temperature proton quantitative nuclear magnetic resonance (VT-1H-qNMR) for the calibration of three C-glycosylflavones including orientin, isoorientin, and schaftoside as reference substances was reported. Since there was conformational equilibrium due to the restricted rotation around the C(sp3)-C(sp2) bond in C-glycosylflavones, the conformational behaviors were investigated by VT-NMR and verified by molecular mechanics (MM) calculation. The VT-1H-qNMR method was validated including the linearity, limit of quantification, precision, and stability. The results were consistent with those obtained from mass balance approach. VT-1H-qNMR can be deployed as an effective tool in analyzing C-glycosylflavones. PMID:28243484

  5. Absolute quantification for benzoic acid in processed foods using quantitative proton nuclear magnetic resonance spectroscopy.

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    Ohtsuki, Takashi; Sato, Kyoko; Sugimoto, Naoki; Akiyama, Hiroshi; Kawamura, Yoko

    2012-09-15

    The absolute quantification method of benzoic acid (BA) in processed foods using solvent extraction and quantitative proton nuclear magnetic resonance spectroscopy was developed and validated. BA levels were determined using proton signals (δ(H) 7.53 and 7.98) referenced to 2-dimethyl-2-silapentane-5-sulfonate-d(6) sodium salt (DSS-d(6)) after simple solvent extraction from processed foods. All recoveries from several kinds of processed foods, spiked at their specified maximum Japanese usage levels (0.6-2.5 g kg(-1)) and at 0.13 g kg(-1) and 0.063 g kg(-1), were greater than 80%. The limit of quantification was confirmed as 0.063 g kg(-1) in processed foods, which was sufficiently low for the purposes of monitoring BA. The accuracy of the proposed method is equivalent to the conventional method using steam-distillation extraction and high-performance liquid chromatography. The proposed method was both rapid and simple. Moreover, it provided International System of Units traceability without the need for authentic analyte standards. Therefore, the proposed method is a useful and practical tool for determining BA levels in processed foods.

  6. Proton magnetic resonance spectroscopy of normal human brain and glioma:a quantitive in vivo study

    Institute of Scientific and Technical Information of China (English)

    TONG Zhi-yong; YAMAKI Toshiaki; WANG Yun-jie

    2005-01-01

    Background In vivo proton magnetic resonance spectroscopy (MRS) provides a noninvasive method of examining a wide variety of cerebral metabolites in both healthy subjects and patients with various brain diseases.Absolute metabolite concentrations have been determined using external and internal standards with known concentrations.When an external standard is placed beside the head, variations in signal amplitudes due to B1 field inhomogeneity and static field inhomogeneity may occur.Hence an internal standard is preferable.The purpose of this study was to quantitatively analyze the metabolite concentrations in normal adult brains and gliomas by in vivo proton MRS using the fully relaxed water signal as an internal standard.Methods Between January 1998 and October 2001, 28 healthy volunteers and 16 patients with gliomas were examined by in vivo proton MRS.Single-voxel spectra were acquired using the point-resolved spectroscopic pulse sequence with a 1.5 T scanner (TR/TE/Ave=3000 ms/30 ms/64).Results The calculated concentrations of N-acetyl-asparatate (NAA), creatine (Cre), choline (Cho), and water (H2O) in the normal hemispheric white matter were (23.59±2.62) mmol/L, (13.06±1.8) mmol/L, (4.28±0.8) mmol/L, and (47 280.96±5414.85) mmol/L, respectively.The metabolite concentrations were not necessarily uniform in different parts of the brain.The concentrations of NAA and Cre decreased in all gliomas (P<0.001).The ratios of NAA/Cho and NAA/H2O showed a significant difference between the normal brain and gliomas, and also between the high and low grades (P<0.001).Conclusions Quantitative analysis of in vivo proton MR spectra using the fully relaxed water signal as an internal standard is useful.The concentrations of NAA and the ratios of NAA/H2O and NAA/Cho conduce to discriminating between the glioma and normal brain, and also between the low-grade glioma and high-grade glioma.

  7. Absolute quantitative analysis for sorbic acid in processed foods using proton nuclear magnetic resonance spectroscopy.

    Science.gov (United States)

    Ohtsuki, Takashi; Sato, Kyoko; Sugimoto, Naoki; Akiyama, Hiroshi; Kawamura, Yoko

    2012-07-13

    An analytical method using solvent extraction and quantitative proton nuclear magnetic resonance (qHNMR) spectroscopy was applied and validated for the absolute quantification of sorbic acid (SA) in processed foods. The proposed method showed good linearity. The recoveries for samples spiked at the maximum usage level specified for food in Japan and at 0.13 g kg(-1) (beverage: 0.013 g kg(-1)) were larger than 80%, whereas those for samples spiked at 0.063 g kg(-1) (beverage: 0.0063 g kg(-1)) were between 56.9 and 83.5%. The limit of quantification was 0.063 g kg(-1) for foods (and 0.0063 g kg(-1) for beverages containing Lactobacillus species). Analysis of the SA content of commercial processed foods revealed quantities equal to or greater than those measured using conventional steam-distillation extraction and high-performance liquid chromatography quantification. The proposed method was rapid, simple, accurate, and precise, and provided International System of Units traceability without the need for authentic analyte standards. It could therefore be used as an alternative to the quantification of SA in processed foods using conventional method.

  8. Absolute quantitative analysis for sorbic acid in processed foods using proton nuclear magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ohtsuki, Takashi, E-mail: ohtsuki@nihs.go.jp [National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501 (Japan); Sato, Kyoko; Sugimoto, Naoki; Akiyama, Hiroshi; Kawamura, Yoko [National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501 (Japan)

    2012-07-13

    Highlights: Black-Right-Pointing-Pointer A method using qHNMR was applied and validated to determine SA in processed foods. Black-Right-Pointing-Pointer This method has good accuracy, precision, selectiveness, and linearity. Black-Right-Pointing-Pointer The proposed method is more rapid and simple than the conventional method. Black-Right-Pointing-Pointer We found that the proposed method is reliable for the accurate determination of SA. Black-Right-Pointing-Pointer This method can be used for the monitoring of SA in processed foods. - Abstract: An analytical method using solvent extraction and quantitative proton nuclear magnetic resonance (qHNMR) spectroscopy was applied and validated for the absolute quantification of sorbic acid (SA) in processed foods. The proposed method showed good linearity. The recoveries for samples spiked at the maximum usage level specified for food in Japan and at 0.13 g kg{sup -1} (beverage: 0.013 g kg{sup -1}) were larger than 80%, whereas those for samples spiked at 0.063 g kg{sup -1} (beverage: 0.0063 g kg{sup -1}) were between 56.9 and 83.5%. The limit of quantification was 0.063 g kg{sup -1} for foods (and 0.0063 g kg{sup -1} for beverages containing Lactobacillus species). Analysis of the SA content of commercial processed foods revealed quantities equal to or greater than those measured using conventional steam-distillation extraction and high-performance liquid chromatography quantification. The proposed method was rapid, simple, accurate, and precise, and provided International System of Units traceability without the need for authentic analyte standards. It could therefore be used as an alternative to the quantification of SA in processed foods using conventional method.

  9. Toward a quantitative analysis of in vivo proton magnetic resonance spectroscopic signals using the continuous Morlet wavelet transform

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    Suvichakorn, A.; Ratiney, H.; Bucur, A.; Cavassila, S.; Antoine, J. P.

    2009-10-01

    We apply the Morlet wavelet transform (MWT) for quantitatively analyzing proton magnetic resonance spectroscopic (MRS) signals, more precisely signals acquired at short echo time. These signals contain many resonating components whose frequencies are characteristic of the observed metabolites, and amplitudes are directly related to the concentrations of these metabolites. With these powerful properties, in vivo MRS can be considered as a unique non-invasive tool to explore biochemical compounds of living tissues. However, the analysis and quantification of these metabolite contributions are difficult due to the low signal-to-noise ratio, the number of overlapping frequencies and the contamination of the signal of interest with water and a baseline originating from macromolecules and lipids. The baseline is a major obstacle for MRS quantification as its shape and intensity are generally not known a priori. In this paper, we present the methodology to quantify the signals by the MWT. We assess the ability of the proposed method to recover parameters such as metabolite amplitudes, frequencies and damping factors while facing successively quantification challenges arising from the non-Lorentzian lineshapes, overlapping frequencies, and noise or baseline. Tests of the method are performed on simulated signals alone or combined with either in vitro acquisition and/or in vivo macromolecular signal acquired on a horizontal 4.7 T scanner. In presence of the macromolecules, the amplitude parameter is correctly derived by the method, thanks to the time-scale representation of the wavelet which enables us to distinguish the two signals by their time decays and without any additional pre-processing.

  10. High-resolution three-dimensional macromolecular proton fraction mapping for quantitative neuroanatomical imaging of the rodent brain in ultra-high magnetic fields.

    Science.gov (United States)

    Naumova, Anna V; Akulov, Andrey E; Khodanovich, Marina Yu; Yarnykh, Vasily L

    2017-02-15

    A well-known problem in ultra-high-field MRI is generation of high-resolution three-dimensional images for detailed characterization of white and gray matter anatomical structures. T1-weighted imaging traditionally used for this purpose suffers from the loss of contrast between white and gray matter with an increase of magnetic field strength. Macromolecular proton fraction (MPF) mapping is a new method potentially capable to mitigate this problem due to strong myelin-based contrast and independence of this parameter of field strength. MPF is a key parameter determining the magnetization transfer effect in tissues and defined within the two-pool model as a relative amount of macromolecular protons involved into magnetization exchange with water protons. The objectives of this study were to characterize the two-pool model parameters in brain tissues in ultra-high magnetic fields and introduce fast high-field 3D MPF mapping as both anatomical and quantitative neuroimaging modality for small animal applications. In vivo imaging data were obtained from four adult male rats using an 11.7T animal MRI scanner. Comprehensive comparison of brain tissue contrast was performed for standard R1 and T2 maps and reconstructed from Z-spectroscopic images two-pool model parameter maps including MPF, cross-relaxation rate constant, and T2 of pools. Additionally, high-resolution whole-brain 3D MPF maps were obtained with isotropic 170µm voxel size using the single-point synthetic-reference method. MPF maps showed 3-6-fold increase in contrast between white and gray matter compared to other parameters. MPF measurements by the single-point synthetic reference method were in excellent agreement with the Z-spectroscopic method. MPF values in rat brain structures at 11.7T were similar to those at lower field strengths, thus confirming field independence of MPF. 3D MPF mapping provides a useful tool for neuroimaging in ultra-high magnetic fields enabling both quantitative tissue

  11. Region-specific effects on brain metabolites of hypoxia and hyperoxia overlaid on cerebral ischemia in young and old rats: a quantitative proton magnetic resonance spectroscopy study

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    Giuliani Patricia

    2010-02-01

    Full Text Available Abstract Background Both hypoxia and hyperoxia, deregulating the oxidative balance, may play a role in the pathology of neurodegenerative disorders underlain by cerebral ischemia. In the present study, quantitative proton magnetic resonance spectroscopy was used to evaluate regional metabolic alterations, following a 24-hour hypoxic or hyperoxic exposure on the background of ischemic brain insult, in two contrasting age-groups of rats: young - 3 months old and aged - 24 months old. Methods Cerebral ischemia was induced by ligation of the right common carotid artery. Concentrations of eight metabolites (alanine, choline-containing compounds, total creatine, γ-aminobutyric acid, glutamate, lactate, myo-inositol and N-acetylaspartate were quantified from extracts in three different brain regions (fronto-parietal and occipital cortices and the hippocampus from both hemispheres. Results In the control normoxic condition, there were significant increases in lactate and myo-inositol concentrations in the hippocampus of the aged rats, compared with the respective values in the young ones. In the ischemia-hypoxia condition, the most prevalent changes in the brain metabolites were found in the hippocampal regions of both young and aged rats; but the effects were more evident in the aged animals. The ischemia-hyperoxia procedure caused less dedicated changes in the brain metabolites, which may reflect more limited tissue damage. Conclusions We conclude that the hippocampus turns out to be particularly susceptible to hypoxia overlaid on cerebral ischemia and that old age further increases this susceptibility.

  12. FLASH proton density imaging for improved surface coil intensity correction in quantitative and semi-quantitative SSFP perfusion cardiovascular magnetic resonance.

    Science.gov (United States)

    Nielles-Vallespin, Sonia; Kellman, Peter; Hsu, Li-Yueh; Arai, Andrew E

    2015-02-17

    A low excitation flip angle (α coil intensity correction (SCIC) of the saturation-recovery (SR) prepared high flip angle (α = 40-50°) SSFP myocardial perfusion images. The different SSFP off-resonance response for these two flip angles might lead to suboptimal SCIC when there is a spatial variation in the background B0-field. The low flip angle SSFP-PD frames are more prone to parallel imaging banding artifacts in the presence of off-resonance. The use of FLASH-PD frames would eliminate both the banding artifacts and the uneven frequency response in the presence of off-resonance in the surface coil inhomogeneity estimate and improve homogeneity of semi-quantitative and quantitative perfusion measurements. B0-field maps, SSFP and FLASH-PD frames were acquired in 10 healthy volunteers to analyze the SSFP off-resonance response. Furthermore, perfusion scans preceded by both FLASH and SSFP-PD frames from 10 patients with no myocardial infarction were analyzed semi-quantitatively and quantitatively (rest n = 10 and stress n = 1). Intra-subject myocardial blood flow (MBF) coefficient of variation (CoV) over the whole left ventricle (LV), as well as intra-subject peak contrast (CE) and upslope (SLP) standard deviation (SD) over 6 LV sectors were investigated. In the 6 out of 10 cases where artifacts were apparent in the LV ROI of the SSFP-PD images, all three variability metrics were statistically significantly lower when using the FLASH-PD frames as input for the SCIC (CoVMBF-FLASH = 0.3 ± 0.1, CoVMBF-SSFP = 0.4 ± 0.1, p = 0.03; SDCE-FLASH = 10 ± 2, SDCE-SSFP = 32 ± 7, p = 0.01; SDSLP-FLASH = 0.02 ± 0.01, SDSLP-SSFP = 0.06 ± 0.02, p = 0.03). Example rest and stress data sets from the patient pool demonstrate that the low flip angle SSFP protocol can exhibit severe ghosting artifacts originating from off-resonance banding artifacts at the edges of the field of view that parallel imaging is

  13. Quantitative shadowgraphy and proton radiography for large intensity modulations

    CERN Document Server

    Kasim, Muhammad Firmansyah; Ratan, Naren; Sadler, James; Chen, Nicholas; Savert, Alexander; Trines, Raoul; Bingham, Robert; Burrows, Philip N; Kaluza, Malte C; Norreys, Peter

    2016-01-01

    Shadowgraphy is a technique widely used to diagnose objects or systems in various fields in physics and engineering. In shadowgraphy, an optical beam is deflected by the object and then the intensity modulation is captured on a screen placed some distance away. However, retrieving quantitative information from the shadowgrams themselves is a challenging task because of the non-linear nature of the process. Here, a novel method to retrieve quantitative information from shadowgrams, based on computational geometry, is presented for the first time. This process can be applied to proton radiography for electric and magnetic field diagnosis in high-energy-density plasmas and has been benchmarked using a toroidal magnetic field as the object, among others. It is shown that the method can accurately retrieve quantitative parameters with error bars less than 10%, even when caustics are present. The method is also shown to be robust enough to process real experimental results with simple pre- and post-processing techn...

  14. Chemical Principles Revisited. Proton Magnetic Resonance Spectroscopy.

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    McQuarrie, Donald A.

    1988-01-01

    Discusses how to interpret nuclear magnetic resonance (NMR) spectra and how to use them to determine molecular structures. This discussion is limited to spectra that are a result of observation of only the protons in a molecule. This type is called proton magnetic resonance (PMR) spectra. (CW)

  15. Quantitative shadowgraphy and proton radiography for large intensity modulations

    Science.gov (United States)

    Kasim, Muhammad Firmansyah; Ceurvorst, Luke; Ratan, Naren; Sadler, James; Chen, Nicholas; Sävert, Alexander; Trines, Raoul; Bingham, Robert; Burrows, Philip N.; Kaluza, Malte C.; Norreys, Peter

    2017-02-01

    Shadowgraphy is a technique widely used to diagnose objects or systems in various fields in physics and engineering. In shadowgraphy, an optical beam is deflected by the object and then the intensity modulation is captured on a screen placed some distance away. However, retrieving quantitative information from the shadowgrams themselves is a challenging task because of the nonlinear nature of the process. Here, we present a method to retrieve quantitative information from shadowgrams, based on computational geometry. This process can also be applied to proton radiography for electric and magnetic field diagnosis in high-energy-density plasmas and has been benchmarked using a toroidal magnetic field as the object, among others. It is shown that the method can accurately retrieve quantitative parameters with error bars less than 10%, even when caustics are present. The method is also shown to be robust enough to process real experimental results with simple pre- and postprocessing techniques. This adds a powerful tool for research in various fields in engineering and physics for both techniques.

  16. Regional brain metabolite abnormalities in inherited prion disease and asymptomatic gene carriers demonstrated in vivo by quantitative proton magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Waldman, A.D.; Cordery, R.J.; Godbolt, A.; Rossor, M.N. [University College London, Dementia Research Group, Department of Neurodegenerative Disease, Institute of Neurology, London (United Kingdom); Imperial College of Science, Technology and Medicine, Division of Neuroscience and Psychological Medicine, Faculty of Medicine, London (United Kingdom); MacManus, D.G. [University College London, NMR Research Unit, Department of Clinical Neurology, Institute of Neurology, London (United Kingdom); Collinge, J. [University College London, MRC Prion Unit, Department of Neurodegenerative Disease, Institute of Neurology, London (United Kingdom)

    2006-06-15

    Inherited prion diseases are caused by mutations in the gene which codes for prion protein (PrP), leading to proliferation of abnormal PrP isomers in the brain and neurodegeneration; they include Gerstmann-Straeussler-Scheinker disease (GSS), fatal familial insomnia (FFI) and familial Creutzfeldt-Jakob disease (fCJD). We studied two patients with symptomatic inherited prion disease (P102L) and two pre-symptomatic P102L gene carriers using quantitative magnetic resonance spectroscopy (MRS). Short echo time spectra were acquired from the thalamus, caudate region and frontal white matter, metabolite levels and ratios were measured and z-scores calculated for individual patients relative to age-matched normal controls. MRS data were compared with structural magnetic resonance imaging. One fCJD case had generalised atrophy and showed increased levels of myo-inositol (MI) in the thalamus (z=3.7). The other had decreased levels of N-acetylaspartate (z=4) and diffuse signal abnormality in the frontal white matter. Both asymptomatic gene carriers had normal imaging, but increased frontal white matter MI (z=4.3, 4.1), and one also had increased MI in the caudate (z=5.3). Isolated MI abnormalities in asymptomatic gene carriers are a novel finding and may reflect early glial proliferation, prior to significant neuronal damage. MRS provides potential non-invasive surrogate markers of early disease and progression in inherited prion disease. (orig.)

  17. Direct Analysis of Free and Sulfite-Bound Carbonyl Compounds in Wine by Two-Dimensional Quantitative Proton and Carbon Nuclear Magnetic Resonance Spectroscopy.

    Science.gov (United States)

    Nikolantonaki, Maria; Magiatis, Prokopios; Waterhouse, Andrew L

    2015-11-03

    Recent developments that have accelerated 2D NMR methods and improved quantitation have made these methods accessible analytical procedures, and the large signal dispersion allows for the analysis of complex samples. Few natural samples are as complex as wine, so the application to challenges in wine analysis look promising. The analysis of carbonyl compounds in wine, key oxidation products, is complicated by a multitude of kinetically reversible adducts, such as acetals and sulfonates, so that sample preparation steps can generate complex interferences. These challenges could be overcome if the compounds could be quantified in situ. Here, two-dimensional ((1)H-(1)H) homonuclear and heteronuclear ((13)C-(1)H) single quantum correlations (correlation spectroscopy, COSY, and heteronuclear single quantum coherence, HSQC) nuclear magnetic resonance spectra of undiluted wine samples were observed at natural abundance. These techniques achieve simultaneous direct identification and quantitation of acetaldehyde, pyruvic acid, acetoin, methylglyoxal, and α-ketoglutaric acid in wine with only a small addition of D2O. It was also possible to observe and sometimes quantify the sulfite, hydrate, and acetal forms of the carbonyl compounds. The accuracy of the method was tested in wine samples by spiking with a mixture of all analytes at different concentrations. The method was applied to 15 wine samples of various vintages and grape varieties. The application of this method could provide a powerful tool to better understand the development, evolution, and perception of wine oxidation and insight into the impact of these sulfite bound carbonyls on antimicrobial and antioxidant action by SO2.

  18. Proton acceleration from magnetized overdense plasmas

    Science.gov (United States)

    Kuri, Deep Kumar; Das, Nilakshi; Patel, Kartik

    2017-01-01

    Proton acceleration by an ultraintense short pulse circularly polarized laser from an overdense three dimensional (3D) particle-in-cell (PIC) 3D-PIC simulations. The axial magnetic field modifies the dielectric constant of the plasma, which causes a difference in the behaviour of ponderomotive force in case of left and right circularly polarized laser pulse. When the laser is right circularly polarized, the ponderomotive force gets enhanced due to cyclotron effects generating high energetic electrons, which, on reaching the target rear side accelerates the protons via target normal sheath acceleration process. On the other hand, in case of left circular polarization, the effects get reversed causing a suppression of the ponderomotive force at a short distance and lead towards a rise in the radiation pressure, which results in the effective formation of laser piston. Thus, the axial magnetic field enhances the effect of radiation pressure in case of left circularly polarized laser resulting in the generation of high energetic protons at the target front side. The transverse motion of protons get reduced as they gyrate around the axial magnetic field which increases the beam collimation to some extent. The optimum thickness of the overdense plasma target is found to be increased in the presence of an axial magnetic field.

  19. On electron-proton energy exchange in strong magnetic field

    Science.gov (United States)

    Zelener, B. B.; Zelener, B. V.; Manykin, E. A.; Bronin, S. Y.; Bobrov, A. A.

    2016-11-01

    Heating of protons in cold electron gas in strong magnetic field is studied. Calculations of heating process are preformed using molecular dynamics method. Estimations of heating rate depending on initial proton energies and electron gas temperatures are made.

  20. Brain proton magnetic resonance spectroscopy for hepatic encephalopathy

    Science.gov (United States)

    Ong, Chin-Sing; McConnell, James R.; Chu, Wei-Kom

    1993-08-01

    Liver failure can induce gradations of encephalopathy from mild to stupor to deep coma. The objective of this study is to investigate and quantify the variation of biochemical compounds in the brain in patients with liver failure and encephalopathy, through the use of water- suppressed, localized in-vivo Proton Magnetic Resonance Spectroscopy (HMRS). The spectral parameters of the compounds quantitated are: N-Acetyl Aspartate (NAA) to Creatine (Cr) ratio, Choline (Cho) to Creatine ratio, Inositol (Ins) to Creatine ratio and Glutamine-Glutamate Amino Acid (AA) to Creatine ratio. The study group consisted of twelve patients with proven advanced chronic liver failure and symptoms of encephalopathy. Comparison has been done with results obtained from five normal subjects without any evidence of encephalopathy or liver diseases.

  1. Enhanced proton acceleration in an applied longitudinal magnetic field

    CERN Document Server

    Arefiev, Alexey; Fiksel, Gennady

    2016-01-01

    Using two-dimensional particle-in-cell simulations, we examine how an externally applied strong magnetic impacts proton acceleration in laser-irradiated solid-density targets. We find that a kT-level external magnetic field can sufficiently inhibit transverse transport of hot electrons in a flat laser-irradiated target. While the electron heating by the laser remains mostly unaffected, the reduced electron transport during proton acceleration leads to an enhancement of maximum proton energies and the overall number of energetic protons. The resulting proton beam is much better collimated compared to a beam generated without applying a kT-level magnetic field. A factor of three enhancement of the laser energy conversion efficiency into multi-MeV protons is another effect of the magnetic field. The required kT magnetic fields are becoming feasible due to a significant progress that has been made in generating magnetic fields with laser-driven coils using ns-long laser pulses. The predicted improved characterist...

  2. Single-Plane Magnetically Focused Elongated Small Field Proton Beams.

    Science.gov (United States)

    McAuley, Grant A; Slater, James M; Wroe, Andrew J

    2015-08-01

    We previously performed Monte Carlo simulations of magnetically focused proton beams shaped by a single quadrapole magnet and thereby created narrow elongated beams with superior dose delivery characteristics (compared to collimated beams) suitable for targets of similar geometry. The present study seeks to experimentally validate these simulations using a focusing magnet consisting of 24 segments of samarium cobalt permanent magnetic material adhered into a hollow cylinder. Proton beams with properties relevant to clinical radiosurgery applications were delivered through the magnet to a water tank containing a diode detector or radiochromic film. Dose profiles were analyzed and compared with analogous Monte Carlo simulations. The focused beams produced elongated beam spots with high elliptical symmetry, indicative of magnet quality. Experimental data showed good agreement with simulations, affirming the utility of Monte Carlo simulations as a tool to model the inherent complexity of a magnetic focusing system. Compared to target-matched unfocused simulations, focused beams showed larger peak to entrance ratios (26% to 38%) and focused simulations showed a two-fold increase in beam delivery efficiency. These advantages can be attributed to the magnetic acceleration of protons in the transverse plane that tends to counteract the particle outscatter that leads to degradation of peak to entrance performance in small field proton beams. Our results have important clinical implications and suggest rare earth focusing magnet assemblies are feasible and could reduce skin dose and beam number while delivering enhanced dose to narrow elongated targets (eg, in and around the spinal cord) in less time compared to collimated beams.

  3. Helical Dipole Magnets for Polarized Protons in RHIC

    Science.gov (United States)

    Syphers, M.; Courant, E.; Fischer, W.; Luccio, A.; Mariam, F.; Peggs, S.; Pilat, F.; Roser, T.; Tepikian, S.; Tsoupas, N.; Willen, E.; Katayama, T.; Hatanaka, K.; Kawaguchi, T.; Okamura, M.; Tominaka, T.; Wu, H.; Ptitsin, V.; Shatunov, Y.

    1997-05-01

    The Brookhaven Relativistic Heavy Ion Collider (RHIC) will be able to support experiments using polarized proton beams. Siberian Snakes are used to maintain polarization in this high energy superconducting collider. To make efficient use of available space while taking advantage of high field superconducting magnets, 4 Tesla helical dipole magnets will be used. These magnets generate a central dipole field in which the field direction rotates through 360^circ about the longitudinal axis over the length of the device. An arrangement of four such magnets can produce the desired change in the spin direction while keeping the proton orbit outside of the ``Snake'' unaltered. Similar magnet arrangements will be used to produce longitudinal polarization at the two major interaction points in RHIC. The basic requirements and layout of these magnets are described, as well as tolerances on field quality and integrated field strengths. First results of tests of prototype helical magnets will be discussed.

  4. Inferring Morphology and Strength of Magnetic Fields From Proton Radiographs

    CERN Document Server

    Graziani, Carlo; Lamb, Donald Q; Li, Chikang

    2016-01-01

    Proton radiography is an important diagnostic method for laser plasma experiments, and is particularly important in the analysis of magnetized plasmas. The theory of radiographic image analysis has heretofore only permitted somewhat limited analysis of the radiographs of such plasmas. We furnish here a theory that remedies this deficiency. We show that to linear order in magnetic field gradients, proton radiographs are projection images of the MHD current along the proton trajectories. We demonstrate that in the linear approximation, the full structure of the perpedicular magnetic field can be reconstructed by solving a steady-state inhomogeneous 2-dimensional diffusion equation sourced by the radiograph fluence contrast data. We explore limitations of the inversion method due to Poisson noise, to discretization errors, to radiograph edge effects, and to obstruction by laser target structures. We also provide a separate analysis that is well-suited to the inference of isotropic-homogeneous magnetic turbulence...

  5. Proton magnetic relaxation dispersion in aqueous biopolymer systems

    Science.gov (United States)

    Conti, S.

    Investigation of the magnetic field dependence of proton spin-lattice relaxation in solutions of bovine fibrinogen has been performed for Larmor frequencies between 50 Hz and 60 MHz, and complemented with measurements of spin-spin relaxation rates at 2 kHz and 25 MHz. A thorough analysis of experimental data, including the effects of protein concentration, temperature, pH and isotopic dilution, leads to an overall relaxation scheme consistent with T1 and T2 values at both low and high magnetic fields. The scheme involves water molecules slightly anisotropically bound on proteins as well as slow exchanging protein protons magnetically coupled to solute nuclei. A coherent picture, reminiscent of the traditional hydration layer, can be obtained for bound water. A major conclusion is that transfer of single protons may contribute substantially to the chemical exchange between free and bound water.

  6. Magnetic properties of point defects in proton irradiated diamond

    Energy Technology Data Exchange (ETDEWEB)

    Makgato, T.N., E-mail: Thuto.Makgato@students.wits.ac.za [School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); Sideras-Haddad, E. [School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); Center of Excellence in Strong Materials, Physics Building, University of the Witwatersrand, Johannesburg 2050 (South Africa); Ramos, M.A. [CMAM, Centro de Micro-Analisis de Materiales, Universidad Autónoma de Madrid, C/Faraday 3, Campus de Cantoblanco, E-28049 Madrid (Spain); Departamento de Fisica de la Materia Condensada, Condensed Matter Physics Center (IFIMAC) and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, 28049 Madrid (Spain); García-Hernández, M. [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain); Climent-Font, A.; Zucchiatti, A.; Muñoz-Martin, A. [CMAM, Centro de Micro-Analisis de Materiales, Universidad Autónoma de Madrid, C/Faraday 3, Campus de Cantoblanco, E-28049 Madrid (Spain); Shrivastava, S. [School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); Erasmus, R. [School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); Center of Excellence in Strong Materials, Physics Building, University of the Witwatersrand, Johannesburg 2050 (South Africa)

    2016-09-01

    We investigate the magnetic properties of ultra-pure type-IIa diamond following irradiation with proton beams of ≈1–2 MeV energy. SQUID magnetometry indicate the formation of Curie type paramagnetism according to the Curie law. Raman and Photoluminescence spectroscopy measurements show that the primary structural features created by proton irradiation are the centers: GR1, ND1, TR12 and 3H. The Stopping and Range of Ions in Matter (SRIM) Monte Carlo simulations together with SQUID observations show a strong correlation between vacancy production, proton fluence and the paramagnetic factor. At an average surface vacancy spacing of ≈1–1.6 nm and bulk (peak) vacancy spacing of ≈0.3-0.5 nm Curie paramagnetism is induced by formation of ND1 centres with an effective magnetic moment μ{sub eff}~(0.1–0.2)μ{sub B}. No evidence of long range magnetic ordering is observed in the temperature range 4.2-300 K. - Highlights: • Proton macro-irradiation of pure diamond creates fluence dependent paramagnetism. • The effective magnetic moment is found to be in the range μ{sub eff}~(0.1–0.2)μ{sub B}. • No evidence of long range magnetic ordering is observed.

  7. Mercury's Surface Magnetic Field Determined from Proton-Reflection Magnetometry

    Science.gov (United States)

    Winslow, Reka M.; Johnson, Catherine L.; Anderson, Brian J.; Gershman, Daniel J.; Raines, Jim M.; Lillis, Robert J.; Korth, Haje; Slavin, James A.; Solomon, Sean C.; Zurbuchen, Thomas H.; Zuber, Maria T.

    2014-01-01

    Solar wind protons observed by the MESSENGER spacecraft in orbit about Mercury exhibit signatures of precipitation loss to Mercury's surface. We apply proton-reflection magnetometry to sense Mercury's surface magnetic field intensity in the planet's northern and southern hemispheres. The results are consistent with a dipole field offset to the north and show that the technique may be used to resolve regional-scale fields at the surface. The proton loss cones indicate persistent ion precipitation to the surface in the northern magnetospheric cusp region and in the southern hemisphere at low nightside latitudes. The latter observation implies that most of the surface in Mercury's southern hemisphere is continuously bombarded by plasma, in contrast with the premise that the global magnetic field largely protects the planetary surface from the solar wind.

  8. The magnetic moments of the proton and the antiproton

    CERN Document Server

    Ulmer, S.; Blaum, K.; Braeuninger, S.; Franke, K.; Kracke, H.; Leiteritz, C.; Matsuda, Y.; Nagahama, H.; Ospelkaus, C.; Rodegheri, C.C.; Quint, W.; Schneider, G.; Smorra, C.; Van Gorp, S.; Walz, J.; Yamazaki, Y.

    2014-01-01

    Recent exciting progress in the preparation and manipulation of the motional quantum states of a single trapped proton enabled the first direct detection of the particle's spin state. Based on this success the proton magnetic moment $\\mu_p$ was measured with ppm precision in a Penning trap with a superimposed magnetic field inhomogeneity. An improvement by an additional factor of 1000 in precision is possible by application of the so-called double Penning trap technique. In a recent paper we reported the first demonstration of this method with a single trapped proton, which is a major step towards the first direct high-precision measurement of $\\mu_p$. The techniques required for the proton can be directly applied to measure the antiproton magnetic moment $\\mu_{\\bar{p}}$. An improvement in precision of $\\mu_{\\bar{p}}$ by more than three orders of magnitude becomes possible, which will provide one of the most sensitive tests of CPT invariance. To achieve this research goal we are currently setting up the Baryo...

  9. Three-dimensional proton magnetic resonance spectroscopic imaging with and without an endorectal coil: a prostate phantom study

    NARCIS (Netherlands)

    Ma, C.; Chen, L.; Scheenen, T.W.J.; Lu, J.; Wang, J

    2015-01-01

    Proton magnetic resonance spectroscopic imaging (MRSI) of the prostate has been used with only a combination of external surface coils. The quality of spectral fitting of the (cholinen+ncreatine)/citrate ([Chon+nCr]/Cit) ratio at different field strengths and different coils is important for quantit

  10. Possible magnetism based on orbital motion of protons in ice

    CERN Document Server

    Yen, Fei; Liu, Yongsheng; Berlie, Adam

    2016-01-01

    A peak anomaly is observed in the magnetic susceptibility as a function of temperature in solid H2O near Tp=60 K. At external magnetic fields below 2 kOe, Tp becomes positive in the temperature range between 45 and 66 K. The magnetic field dependence of the susceptibility in the same temperature range exhibits an inverted ferromagnetic hysteretic loop superimposed on top of the diamagnetic signature of ice at fields below 600 Oe. We suggest that a fraction of protons that are capable of undergoing correlated tunneling in a hexagonal path without disrupting the stoichiometry of the lattice create an induced magnetic field opposite to the induced magnetic field created by the electrons upon application of an external field which counters the overall diamagnetism of the material.

  11. Effect of neutron and proton radiations on magnetization of biotite

    CERN Document Server

    Abdurakhimov, A U; Sharipov, S M; Yugaj, V P; Granovskij, A B; Radkovskaya, A A

    2002-01-01

    One analyzes curves of field dependence of magnetization of biotite measured in the initial state under 4.2 K temperature subsequent to irradiation of 14 MeV energy and 1.2 x 10 sup 1 sup 3 cm sup - sup 2 dose neutrons and by 3 MeV energy and 2.2 x 10 sup 1 sup 4 cm sup - sup 2 dose protons, as well as, subsequent to annealing under 1000 deg temperature during 15 min. Irradiation by neutrons and protons was determined to result in increase of magneto-ordered phase content in biotite and, thus, in increase of magnetization of specimen. It is accounted for by formation of oxides in melt radiation thermal peaks and by freezing of high-temperature phase states corresponding to magnetite or solid solution of magnetite and hematite there. Thermal treatment does not change content of magneto-ordered phase in specimens

  12. Magnetic Moment of Proton Drip-Line Nucleus (9)C

    Science.gov (United States)

    Matsuta, K.; Fukuda, M.; Tanigaki, M.; Minamisono, T.; Nojiri, Y.; Mihara, M.; Onishi, T.; Yamaguchi, T.; Harada, A.; Sasaki, M.

    1994-01-01

    The magnetic moment of the proton drip-line nucleus C-9(I(sup (pi)) = 3/2, T(sub 1/2) = 126 ms) has been measured for the first time, using the beta-NMR detection technique with polarized radioactive beams. The measure value for the magnetic moment is 1mu(C-9)! = 1.3914 +/- 0.0005 (mu)N. The deduced spin expectation value of 1.44 is unusually larger than any other ones of even-odd nuclei.

  13. Superconducting Magnet Technology for Future High Energy Proton Colliders

    Science.gov (United States)

    Gourlay, Stephen

    2017-01-01

    Interest in high field dipoles has been given a boost by new proposals to build a high-energy proton-proton collider to follow the LHC and programs around the world are taking on the task to answer the need. Studies aiming toward future high-energy proton-proton colliders at the 100 TeV scale are now being organized. The LHC and current cost models are based on technology close to four decades old and point to a broad optimum of operation using dipoles with fields between 5 and 12T when site constraints, either geographical or political, are not a factor. Site geography constraints that limit the ring circumference can drive the required dipole field up to 20T, which is more than a factor of two beyond state-of-the-art. After a brief review of current progress, the talk will describe the challenges facing future development and present a roadmap for moving high field accelerator magnet technology forward. This work was supported by the Director, Office of Science, High Energy Physics, US Department of Energy, under contract No. DE-AC02-05CH11231.

  14. High order magnetic optics for high dynamic range proton radiography at a kinetic energy of 800 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Sjue, S. K. L., E-mail: sjue@lanl.gov; Mariam, F. G.; Merrill, F. E.; Morris, C. L.; Saunders, A. [Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2016-01-15

    Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantitative information about density fields in a dynamic experiment from proton generated images requires a high fidelity model of the proton imaging process. It is shown that accurate calculations of the transmission through the magnetic lens system require terms beyond second order for protons far from the tune energy. The approach used integrates the correlated multiple Coulomb scattering distribution simultaneously over the collimator and the image plane. Comparison with a series of static calibration images demonstrates the model’s accurate reproduction of both the transmission and blur over a wide range of tune energies in an inverse identity lens that consists of four quadrupole electromagnets.

  15. Electric and magnetic form factors of the proton

    CERN Document Server

    Bernauer, J C; Friedrich, J.; Walcher, Th.; Achenbach, P.; Gayoso, C. Ayerbe; Böhm, R.; Bosnar, D.; Debenjak, L.; Doria, L.; Esser, A.; Fonvieille, H.; Gomez Rodriguez de la Paz, M.; Friedrich, J.M.; Makek, M.; Merkel, H.; Middleton, D.G.; Müller, U.; Nungesser, L.; Pochodzalla, J.; Potokar, M.; Sanchez Majos, S.; Schlimme, B.S.; Sirca, S.; Weinriefer, M.

    2014-01-01

    The paper describes a precise measurement of electron scattering off the proton at momentum transfers of $0.003 \\lesssim Q^2 \\lesssim 1$\\ GeV$^2$. The average point-to-point error of the cross sections in this experiment is $\\sim$ 0.37%. These data are used for a coherent new analysis together with all world data of unpolarized and polarized electron scattering from the very smallest to the highest momentum transfers so far measured. The extracted electric and magnetic form factors provide new insight into their exact shape, deviating from the classical dipole form, and of structure on top of this gross shape. The data reaching very low $Q^2$ values are used for a new determination of the electric and magnetic radii. An empirical determination of the Two-Photon-Exchange (TPE) correction is presented. The implications of this correction on the radii and the question of a directly visible signal of the pion cloud are addressed.

  16. Quantitative proton imaging from multiple physics processes: a proof of concept.

    Science.gov (United States)

    Bopp, C; Rescigno, R; Rousseau, M; Brasse, D

    2015-07-07

    Proton imaging is developed in order to improve the accuracy of charged particle therapy treatment planning. It makes it possible to directly map the relative stopping powers of the materials using the information on the energy loss of the protons. In order to reach a satisfactory spatial resolution in the reconstructed images, the position and direction of each particle is recorded upstream and downstream from the patient. As a consequence of individual proton detection, information on the transmission rate and scattering of the protons is available. Image reconstruction processes are proposed to make use of this information. A proton tomographic acquisition of an anthropomorphic head phantom was simulated. The transmission rate of the particles was used to reconstruct a map of the macroscopic cross section for nuclear interactions of the materials. A two-step iterative reconstruction process was implemented to reconstruct a map of the inverse scattering length of the materials using the scattering of the protons. Results indicate that, while the reconstruction processes should be optimized, it is possible to extract quantitative information from the transmission rate and scattering of the protons. This suggests that proton imaging could provide additional knowledge on the materials that may be of use to further improve treatment planning.

  17. High-resolution three-dimensional quantitative map of the macromolecular proton fraction distribution in the normal rat brain

    Directory of Open Access Journals (Sweden)

    Anna V. Naumova

    2017-02-01

    Full Text Available The presented dataset provides a normative high-resolution three-dimensional (3D macromolecular proton fraction (MPF map of the healthy rat brain in vivo and source images used for its reconstruction. The images were acquired using the protocol described elsewhere (Naumova, et al. High-resolution three-dimensional macromolecular proton fraction mapping for quantitative neuroanatomical imaging of the rodent brain in ultra-high magnetic fields. Neuroimage (2016 doi: 10.1016/j.neuroimage.2016.09.036. The map was reconstructed from three source images with different contrast weightings (proton density, T1, and magnetization transfer using the single-point algorithm with a synthetic reference image. Source images were acquired from a living animal on an 11.7 T small animal MRI scanner with isotropic spatial resolution of 170 µm3 and total acquisition time about 1.5 h. The 3D dataset can be used for multiple purposes including interactive viewing of rat brain anatomy, measurements of reference MPF values in various brain structures, and development of image processing techniques for the rodent brain segmentation. It also can serve as a gold standard image for implementation and optimization of rodent brain MRI protocols.

  18. Capture and Transport of Laser Accelerated Protons by Pulsed Magnetic Fields: Advancements Toward Laser-Based Proton Therapy

    Science.gov (United States)

    Burris-Mog, Trevor J.

    The interaction of intense laser light (I > 10 18 W/cm2) with a thin target foil leads to the Target Normal Sheath Acceleration mechanism (TNSA). TNSA is responsible for the generation of high current, ultra-low emittance proton beams, which may allow for the development of a compact and cost effective proton therapy system for the treatment of cancer. Before this application can be realized, control is needed over the large divergence and the 100% kinetic energy spread that are characteristic of TNSA proton beams. The work presented here demonstrates control over the divergence and energy spread using strong magnetic fields generated by a pulse power solenoid. The solenoidal field results in a parallel proton beam with a kinetic energy spread DeltaE/E = 10%. Assuming that next generation lasers will be able to operate at 10 Hz, the 10% spread in the kinetic energy along with the 23% capture efficiency of the solenoid yield enough protons per laser pulse to, for the first time, consider applications in Radiation Oncology. Current lasers can generate proton beams with kinetic energies up to 67.5 MeV, but for therapy applications, the proton kinetic energy must reach 250 MeV. Since the maximum kinetic energy Emax of the proton scales with laser light intensity as Emax ∝ I0.5, next generation lasers may very well accelerate 250 MeV protons. As the kinetic energy of the protons is increased, the magnetic field strength of the solenoid will need to increase. The scaling of the magnetic field B with the kinetic energy of the protons follows B ∝ E1/2. Therefor, the field strength of the solenoid presented in this work will need to be increased by a factor of 2.4 in order to accommodate 250 MeV protons. This scaling factor seems reasonable, even with present technology. This work not only demonstrates control over beam divergence and energy spread, it also allows for us to now perform feasibility studies to further research what a laser-based proton therapy system

  19. Magnetic force microscopy: Quantitative issues in biomaterials

    NARCIS (Netherlands)

    Passeri, D.; Dong, C.; Reggente, M.; Angeloni, L.; Barteri, M.; Scaramuzzo, F.A.; De Angelis, F.; Marinelli, F.; Antonelli, F.; Rinaldi, F.; Marianecci, C.; Carafa, M.; Sorbo, A.; Sordi, D.; Arends, I.W.C.E.; Rossi, M.

    2014-01-01

    Magnetic force microscopy (MFM) is an atomic force microscopy (AFM) based technique in which an AFM tip with a magnetic coating is used to probe local magnetic fields with the typical AFM spatial resolution, thus allowing one to acquire images reflecting the local magnetic properties of the samples

  20. Quantitatively measured photorefractive sensitivity of proton-exchanged lithium niobate, proton-exchanged magnesium oxide-doped lithium niobate, and ion-exchanged potassium titanyl phosphate waveguides.

    Science.gov (United States)

    Kondo, Y; Miyaguchi, S; Onoe, A; Fujii, Y

    1994-06-01

    The photorefractive sensitivities of proton-exchanged lithium niobate waveguides and Rb-ion-exchanged potassium titanyl phosphate waveguides are quantitatively measured, and their influence on waveguide applications is estimated.

  1. Brain proton magnetic resonance spectroscopy of alcohol use disorders.

    Science.gov (United States)

    Meyerhoff, Dieter J

    2014-01-01

    This chapter critically reviews brain proton magnetic resonance spectroscopy ((1)H MRS) studies performed since 1994 in individuals with alcohol use disorders (AUD). We describe the neurochemicals that can be measured in vivo at the most common magnetic field strengths, summarize our knowledge about their general brain functions, and briefly explain some basic human (1)H MRS methods. Both cross-sectional and longitudinal research of individuals in treatment and of treatment-naïve individuals with AUD are discussed and interpreted on the basis of reported neuropathology. As AUDs are highly comorbid with chronic cigarette smoking and illicit substance abuse, we also summarize reports on their respective influences on regional proton metabolite levels. After reviewing research on neurobiologic correlates of relapse and genetic influences on brain metabolite levels, we finish with suggestions on future directions for (1)H MRS studies in AUDs. The review demonstrates that brain metabolic alterations associated with AUDs as well as their cognitive correlates are not simply a consequence of chronic alcohol consumption. Future MR research of AUDs in general has to be better prepared - and supported - to study clinically complex relationships between personality characteristics, comorbidities, neurogenetics, lifestyle, and living environment, as all these factors critically affect an individual's neurometabolic profile. (1)H MRS is uniquely positioned to tackle these complexities by contributing to a comprehensive biopsychosocial profile of individuals with AUD: it can provide non-invasive biochemical information on select regions of the brain at comparatively low overall cost for the ultimate purpose of informing more efficient treatments of AUDs.

  2. Pion Production from Proton Synchrotron Radiation under Strong Magnetic Field in a Relativistic Quantum Approach

    Directory of Open Access Journals (Sweden)

    Maruyama Tomoyuki

    2016-01-01

    Full Text Available We study pion production from proton synchrotron radiation in the presence of strong magnetic fields by using the exact proton propagator in a strong magnetic field and explicitly including the anomalous magnetic moment. Results in this exact quantum approach do not agree with those obtained in the semi-classical approach. Then, we find that the anomalous magnetic moment of the proton greatly enhances the production rate by about two orders magnitude, and that the decay width satisfies a robust scaling law.

  3. Skyrme model study of proton and neutron properties in a strong magnetic field

    Science.gov (United States)

    He, Bing-Ran

    2017-02-01

    The proton and neutron properties in a uniform magnetic field are investigated. The Gell-Mann-Nishijima formula is shown to be satisfied for baryon states. It is found that with increasing magnetic field strength, the proton mass first decreases and then increases, while the neutron mass always increases. The ratio between magnetic moment of proton and neutron increases with the increase of the magnetic field strength. With increasing magnetic field strength, the size of proton first increases and then decreases, while the size of neutron always decreases. The present analysis implies that in the core part of the magnetar, the equation of state depend on the magnetic field, which modifies the mass limit of the magnetar.

  4. Skyrme model study of proton and neutron properties in a strong magnetic field

    CERN Document Server

    He, Bing-Ran

    2016-01-01

    The proton and neutron properties in a uniform magnetic field are investigated. The Gell-Mann-Nishijima formula is shown to be satisfied for baryon states. It is found that with increasing magnetic field strength, the proton mass first decreases and then increases, while the neutron mass always increases. The ratio between magnetic moment of proton and neutron increases with the increase of the magnetic field strength. With increasing magnetic field strength, the size of proton first increases and then decreases, while the size of neutron always decreases. The present analyse implies that in the core part of the magnetar, the equation of state depend on the magnetic field, which modifies the mass limit of the magnetar.

  5. Measuring the Muon g-2 Magnetic Storage Field Via Proton Nuclear Magnetic Resonance

    Science.gov (United States)

    Smith, Matthias; Muon g-2 Collaboration Collaboration

    2016-03-01

    The Muon g - 2 experiment at Fermilab aims to measure the muon anomalous magnetic moment, aμ, to a precision of 140 ppb, using a technique that determines the muon spin precession frequency in the highly uniform magnetic field of a storage ring. Both precession frequency and field determination contribute equally to the final systematic uncertainty. The magnetic field is determined from the measurement of free induction decay (FID) signals provided by a matrix of custom proton nuclear magnetic resonance (pNMR) probes. FID simulations show that we can achieve the required precision for extraction of field values compared to systematic contributions. The recently powered muon storage ring is providing data to evaluate the pNMR measurement results. We will describe the performance to date of this system.

  6. Absolute choline concentration measured by quantitative proton MR spectroscopy correlates with cell density in meningioma

    Energy Technology Data Exchange (ETDEWEB)

    Yue, Qiang [University of Tsukuba, Department of Neurosurgery, Institute of Clinical Medicine, Tsukuba Science City, Ibaraki (Japan)]|[West China Hospital of Sichuan University, Huaxi MR Research Center, Department of Radiology, Chengdu (China); Shibata, Yasushi; Kawamura, Hiraku; Matsumura, Akira [University of Tsukuba, Department of Neurosurgery, Institute of Clinical Medicine, Tsukuba Science City, Ibaraki (Japan); Isobe, Tomonori [Kitasato University, Department of Medical Technology, School of Allied Health Sciences, Minato, Tokyo (Japan); Anno, Izumi [University of Tsukuba, Department of Radiology, Institute of Clinical Medicine, Tsukuba, Ibaraki (Japan); Gong, Qi-Yong [West China Hospital of Sichuan University, Huaxi MR Research Center, Department of Radiology, Chengdu (China)]|[University of Liverpool, Division of Medical Imaging, Faculty of Medicine, Liverpool (United Kingdom)

    2009-01-15

    This study was aimed to investigate the relationship between quantitative proton magnetic resonance spectroscopy (1H-MRS) and pathological changes in meningioma. Twenty-two meningioma cases underwent single voxel 1H-MRS (point-resolved spectroscopy sequence, repetition time/echo time = 2,000 ms/68, 136, 272 ms). Absolute choline (Cho) concentration was calculated using tissue water as the internal reference and corrected according to intra-voxel cystic/necrotic parts. Pathological specimens were stained with MIB-1 antibody to measure cell density and proliferation index. Correlation analysis was performed between absolute Cho concentration and cell density and MIB-1 labeled proliferation index. Average Cho concentration of all meningiomas before correction was 2.95 {+-} 0.86 mmol/kg wet weight. It was increased to 3.23 {+-} 1.15 mmol/kg wet weight after correction. Average cell density of all meningiomas was 333 {+-} 119 cells/HPF, and average proliferation index was 2.93 {+-} 5.72%. A linear, positive correlation between cell density and Cho concentration was observed (r = 0.650, P = 0.001). After correction of Cho concentration, the correlation became more significant (r = 0.737, P < 0.001). However, no significant correlation between Cho concentration and proliferation index was found. There seemed to be a positive correlation trend after correction of Cho concentration but did not reach significant level. Absolute Cho concentration, especially Cho concentration corrected according to intra-voxel cystic/necrotic parts, reflects cell density of meningioma. (orig.)

  7. Sickle cell disease painful crisis and steady state differentiation by proton magnetic resonance.

    Science.gov (United States)

    Fernández, Adolfo A; Cabal, Carlos A; Lores, Manuel A; Losada, Jorge; Pérez, Enrique R

    2009-01-01

    The delay time of the Hb S polymerization process was investigated in 63 patients with sickle cell disease during steady state and 10 during painful crisis starting from spin-spin proton magnetic resonance (PMR) time behavior measured at 36 degrees C and during spontaneous deoxygenation. We found a significant decrease of delay time as a result of the crisis (36 +/- 10%) and two well-differentiated ranges of values for each state: 273-354 min for steady state and 166-229 min for crisis with an uncertainty region of 15%. It is possible to use PMR as an objective and quantitative method in order to differentiate both clinical conditions of the sickle cell patient, but a more clear differentiation can be established comparing the delay time (td) value of one patient during crisis with his own td value during steady state.

  8. A new algebraic method for quantitative proton density mapping using multi-channel coil data.

    Science.gov (United States)

    Cordes, Dietmar; Yang, Zhengshi; Zhuang, Xiaowei; Sreenivasan, Karthik; Mishra, Virendra; Hua, Le H

    2017-08-01

    A difficult problem in quantitative MRI is the accurate determination of the proton density, which is an important quantity in measuring brain tissue organization. Recent progress in estimating proton density in vivo has been based on using the inverse linear relationship between the longitudinal relaxation rate T1 and proton density. In this study, the same type of relationship is being used, however, in a more general framework by constructing 3D basis functions to model the receiver bias field. The novelty of this method is that the basis functions developed are suitable to cover an entire range of inverse linearities between T1 and proton density. The method is applied by parcellating the human brain into small cubes with size 30mm x 30mm x 30mm. In each cube the optimal set of basis functions is determined to model the receiver coil sensitivities using multi-channel (32 element) coil data. For validation, we use arbitrary data from a numerical phantom where the data satisfy the conventional MR signal equations. Using added noise of different magnitude and realizations, we show that the proton densities obtained have a bias close to zero and also low noise sensitivity. The obtained root-mean-square-error rate is less than 0.2% for the estimated proton density in a realistic 3D simulation. As an application, the method is used in a small cohort of MS patients, and proton density values for specific brain structures are determined. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Magnetic quadrupoles lens for hot spot proton imaging in inertial confinement fusion

    Energy Technology Data Exchange (ETDEWEB)

    Teng, J. [Science and Technology on Plasma Physics Laboratory, Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900 (China); Gu, Y.Q., E-mail: yqgu@caep.cn [Science and Technology on Plasma Physics Laboratory, Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900 (China); Center for Applied Physics and Technology, HEDPS, Peking University, Beijing 100871 (China); Chen, J.; Zhu, B.; Zhang, B.; Zhang, T.K.; Tan, F.; Hong, W.; Zhang, B.H. [Science and Technology on Plasma Physics Laboratory, Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900 (China); Wang, X.Q. [Academy of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026 (China)

    2016-08-01

    Imaging of DD-produced protons from an implosion hot spot region by miniature permanent magnetic quadrupole (PMQ) lens is proposed. Corresponding object-image relation is deduced and an adjust method for this imaging system is discussed. Ideal point-to-point imaging demands a monoenergetic proton source; nevertheless, we proved that the blur of image induced by proton energy spread is a second order effect therefore controllable. A proton imaging system based on miniature PMQ lens is designed for 2.8 MeV DD-protons and the adjust method in case of proton energy shift is proposed. The spatial resolution of this system is better than 10 μm when proton yield is above 10{sup 9} and the spectra width is within 10%.

  10. Quantitative Evaluation of the Total Magnetic Moments of Colloidal Magnetic Nanoparticles: A Kinetics-based Method.

    Science.gov (United States)

    Liu, Haiyi; Sun, Jianfei; Wang, Haoyao; Wang, Peng; Song, Lina; Li, Yang; Chen, Bo; Zhang, Yu; Gu, Ning

    2015-06-08

    A kinetics-based method is proposed to quantitatively characterize the collective magnetization of colloidal magnetic nanoparticles. The method is based on the relationship between the magnetic force on a colloidal droplet and the movement of the droplet under a gradient magnetic field. Through computational analysis of the kinetic parameters, such as displacement, velocity, and acceleration, the magnetization of colloidal magnetic nanoparticles can be calculated. In our experiments, the values measured by using our method exhibited a better linear correlation with magnetothermal heating, than those obtained by using a vibrating sample magnetometer and magnetic balance. This finding indicates that this method may be more suitable to evaluate the collective magnetism of colloidal magnetic nanoparticles under low magnetic fields than the commonly used methods. Accurate evaluation of the magnetic properties of colloidal nanoparticles is of great importance for the standardization of magnetic nanomaterials and for their practical application in biomedicine.

  11. Quantitative analysis of proton boron fusion therapy (PBFT) in various conditions

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Joo-Young; Yoon, Do-Kun; Suh, Tae Suk [College of Medicine, Catholic University of Korea, Seoul (Korea, Republic of)

    2015-05-15

    From the theoretical point of view, the PBFT has some strong advantages over currently existing radiotherapy methods. First, boron-based tumor targeting is required prior to performing the treatments such as boron-neutron capture therapy (BNCT). Tumor targeting should be performed before the BNCT by injecting the boronate compound. If boron is not taken up by the normal tissue, the normal tissue can be spared the irradiation by alpha particles. When boron uptake occurs in the target region, selective therapy is possible by neutron capture reaction of labeled boron particles in the target region. Likewise, when boron is distributed in the tumor region for the PBFT, the proposed method can represent a more critical discriminative therapy than either the BNCT or conventional particle therapy. In the conventional proton therapy, in order to deliver a dose to a tumor, the proton beam energy has to be adjusted along the tumor region (e.g., shape and depth). The proton therapy aims at delivering the maximal dose to the tumor by using protons only. In this study, the effectiveness of the PBFT with respect to several physical parameters was evaluated quantitatively by using Monte Carlo simulations. We confirmed that the PBFT can be used to perform critical discriminative therapy. Also, the results of our studies can be used for constructing the PFBT dose database that can be utilized in treatment planning systems (TPSs)

  12. Proton magnetic resonance spectroscopy in 22q11 deletion syndrome.

    Directory of Open Access Journals (Sweden)

    Fabiana da Silva Alves

    Full Text Available OBJECTIVE: People with velo-cardio-facial syndrome or 22q11 deletion syndrome (22q11DS have behavioral, cognitive and psychiatric problems. Approximately 30% of affected individuals develop schizophrenia-like psychosis. Glutamate dysfunction is thought to play a crucial role in schizophrenia. However, it is unknown if and how the glutamate system is altered in 22q11DS. People with 22q11DS are vulnerable for haploinsufficiency of PRODH, a gene that codes for an enzyme converting proline into glutamate. Therefore, it can be hypothesized that glutamatergic abnormalities may be present in 22q11DS. METHOD: We employed proton magnetic resonance spectroscopy ((1H-MRS to quantify glutamate and other neurometabolites in the dorsolateral prefrontal cortex (DLPFC and hippocampus of 22 adults with 22q11DS (22q11DS SCZ+ and without (22q11DS SCZ- schizophrenia and 23 age-matched healthy controls. Also, plasma proline levels were determined in the 22q11DS group. RESULTS: We found significantly increased concentrations of glutamate and myo-inositol in the hippocampal region of 22q11DS SCZ+ compared to 22q11DS SCZ-. There were no significant differences in levels of plasma proline between 22q11DS SCZ+ and 22q11DS SCZ-. There was no relationship between plasma proline and cerebral glutamate in 22q11DS. CONCLUSION: This is the first in vivo(1H-MRS study in 22q11DS. Our results suggest vulnerability of the hippocampus in the psychopathology of 22q11DS SCZ+. Altered hippocampal glutamate and myo-inositol metabolism may partially explain the psychotic symptoms and cognitive impairments seen in this group of patients.

  13. Thixotropic Phenomena in Water: Quantitative Indicators of Casimir-Magnetic Transformations from Vacuum Oscillations (Virtual Particles

    Directory of Open Access Journals (Sweden)

    Michael A. Persinger

    2015-09-01

    Full Text Available The ~1.5 × 10−20 J which is considered a universal quantity and is associated with the movement of protons in water also relates to the ratio of the magnetic moment of a proton divided by its unit charge, multiplied by viscosity and applied over the O-H distance. There is quantitative evidence that thixotropy, the “spontaneous” increased viscosity in water when undisturbed, originates from the transformation of virtual particles or vacuum oscillations to real states through conversion of Casimir-magnetic energies that involve the frequency of the neutral hydrogen line and the upper bound threshold value for intergalactic magnetic fields. The results indicate that ½ of a single electron orbit is real (particle and the other ½ is virtual (wave. The matter equivalent per s for virtual-to-real states for electrons in 1 mL of water with a neutral pH is consistent with the numbers of protons (H+ and the measured range of molecules in the coherent domains for both width and duration of growth and is similar to widths of intergalactic dust grains from which planets and stars may condense. The de Broglie momentum for the lower boundary of the width of coherent domains multiplied by the fine structure velocity of an electron is concurrent with the quantum when one proton is being removed from another and when the upper boundary of the rest mass of a photon is transformed by the product of velocities for putative “entanglement” and light. Theoretical and experimental results indicate that components of thixotropy, such as specific domains of intercalated water molecules, could display excess correlations over very large distances. Because the energies of the universal quantity and water converge it may be a special conduit for discrete transformations from virtual to real states.

  14. Proton radiography of magnetic field produced by ultra-intense laser irradiating capacity-coil target

    CERN Document Server

    Wang, W W; Chen, J; Cai, H B; He, S K; Zhou, W M; Shan, L Q; Lu, F; Wu, Y C; Hong, W; Liu, D X; Bi, B; Zhang, F; Xue, F B; Li, B Y; Zhang, B; He, Y L; He, W; Jiao, J L; Dong, K G; Zhang, F Q; Deng, Z G; Zhang, Z M; Cui, B; Han, D; Zhou, K N; Wang, X D; Zhao, Z Q; Cao, L F; Zhang, B H; He, X T; Gu, Y Q

    2014-01-01

    Ultra-intense ultra-short laser is firstly used to irradiate the capacity-coil target to generate magnetic field. The spatial structure and temporal evolution of huge magnetic fields were studied with time-gated proton radiography method. A magnetic flux density of 40T was measured by comparing the proton deflection and particle track simulations. Although the laser pulse duration is only 30fs, the generated magnetic field can last for over 100 picoseconds. The energy conversion efficiency from laser to magnetic field can reach as high as ~20%. The results indicate that tens of tesla (T) magnetic field could be produced in many ultra intense laser facilities around the world, and higher magnetic field could be produced by picosecond lasers.

  15. A practical guide to in vivo proton magnetic resonance spectroscopy at high magnetic fields.

    Science.gov (United States)

    Xin, Lijing; Tkáč, Ivan

    2017-07-15

    Localized proton magnetic resonance spectroscopy ((1)H-MRS) is a noninvasive tool for measuring in vivo neurochemical information in animal and human brains. With the increase of magnetic field strength, whereas localized (1)H-MRS benefits from higher sensitivity and spectral dispersion, it is challenged by increased spatial inhomogeneity of the B0 and B1 fields, larger chemical shift displacement error, and shortened T2 relaxation times of metabolites. Advanced localized (1)H-MRS methodologies developed for high magnetic fields have shown promising results and allow the measurement of neurochemical profiles with up to 19 brain metabolites, including less-abundant metabolites, such as glutathione, glycine, γ-aminobutyric acid and ascorbate. To provide a practical guide for conducting in vivo(1)H-MRS studies at high magnetic field strength, we reviewed various essential technical aspects from data acquisition (hardware requirements, B1 and B0 inhomogeneity, water suppression, localization sequences and acquisition strategies) to data processing (frequency and phase correction, spectral quality control, spectral fitting and concentration referencing). Additionally, we proposed guidelines for choosing the most appropriate data acquisition and processing approaches to maximize the achievable neurochemical information. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Proton acceleration in three-dimensional non-null magnetic reconnection

    Science.gov (United States)

    Akbari, Z.; Hosseinpour, M.; Mohammadi, M. A.

    2016-10-01

    In a three-dimensional non-null magnetic reconnection, the process of magnetic reconnection takes place in the absence of a null point where the magnetic field vanishes. By randomly injecting a population of 10 000 protons, the trajectory and energy distribution of accelerated protons are investigated in the presence of magnetic and electric fields of a particular model of non-null magnetic reconnection with the typical parameters for the solar corona. The results show that protons are accelerated along the magnetic field lines away from the non-null point only at azimuthal angles where the magnitude of the electric field is strongest and therefore particles obtain kinetic energies of the order of thousands of MeV and even higher. Moreover, the energy distribution of the population depends strongly on the amplitude of the electric and magnetic fields. Comparison shows that a non-null magnetic reconnection is more efficient in accelerating protons to very high GeV energies than a null-point reconnection.

  17. Towards quantitative magnetic resonance assessment in parenchymal liver disease

    NARCIS (Netherlands)

    Runge, J.H.

    2015-01-01

    In this thesis several advanced magnetic resonance (MR) techniques for quantitative measurements in parenchymal liver disease are studied. In particular, certain important hallmarks of liver disease such as steatosis, fibrosis, iron overload and inflammation are studied. Steatosis or fatty liver dis

  18. Quantitative magnetic resonance micro-imaging methods for pharmaceutical research.

    Science.gov (United States)

    Mantle, M D

    2011-09-30

    The use of magnetic resonance imaging (MRI) as a tool in pharmaceutical research is now well established and the current literature covers a multitude of different pharmaceutically relevant research areas. This review focuses on the use of quantitative magnetic resonance micro-imaging techniques and how they have been exploited to extract information that is of direct relevance to the pharmaceutical industry. The article is divided into two main areas. The first half outlines the theoretical aspects of magnetic resonance and deals with basic magnetic resonance theory, the effects of nuclear spin-lattice (T(1)), spin-spin (T(2)) relaxation and molecular diffusion upon image quantitation, and discusses the applications of rapid magnetic resonance imaging techniques. In addition to the theory, the review aims to provide some practical guidelines for the pharmaceutical researcher with an interest in MRI as to which MRI pulse sequences/protocols should be used and when. The second half of the article reviews the recent advances and developments that have appeared in the literature concerning the use of quantitative micro-imaging methods to pharmaceutically relevant research. Copyright © 2010 Elsevier B.V. All rights reserved.

  19. Model independent extraction of the proton magnetic radius from electron scattering

    Science.gov (United States)

    Epstein, Zachary; Paz, Gil; Roy, Joydeep

    2014-10-01

    We combine constraints from analyticity with experimental electron-proton scattering data to determine the proton magnetic radius without model-dependent assumptions on the shape of the form factor. We also study the impact of including electron-neutron scattering data, and ππ→NN ¯ data. Using representative data sets we find for a cut of Q2≤0.5 GeV2, rMp=0.91-0.06+0.03±0.02 fm using just proton scattering data; rMp=0.87-0.05+0.04±0.01 fm adding neutron data; and rMp=0.87-0.02+0.02 fm adding ππ data. We also extract the neutron magnetic radius from these data sets obtaining rMn=0.89-0.03+0.03 fm from the combined proton, neutron, and ππ data.

  20. Comment on "High-Precision Determination of the Electric and Magnetic Form Factors of the Proton"

    CERN Document Server

    Arrington, J

    2011-01-01

    In a recent Letter, Bernauer, et al. present fits to the proton electromagnetic form factors, GEp(Q^2) and GMp(Q^2), along with extracted proton charge and magnetization radii based on large set of new, high statistical precision (<0.2%) cross section measurements. The Coulomb corrections they apply differ dramatically from more modern and complete calculations, implying significant error in their final results.

  1. Long-term follow-up of cerebral infarction patients with proton magnetic resonance spectroscopy

    DEFF Research Database (Denmark)

    Gideon, P; Sperling, B; Arlien-Søborg, P

    1994-01-01

    ) to the chronic stage (> 6 months) with proton magnetic resonance spectroscopy. Cerebral blood flow was measured with single-photon emission-computed tomography with 99mTc-labeled d,l-hexamethylenepropyleneamine oxime as flow tracer. RESULTS: Lactate was found in all patients in the acute stage of stroke. Lactate......BACKGROUND AND PURPOSE: With proton magnetic resonance spectroscopy it is possible to measure the content of various brain metabolites in vivo, including N-acetylaspartate (which may be used as a neuronal marker), creatine, choline, and lactate. The content of these brain metabolites was measured...... connection between the reduction of cerebral blood flow and the spectroscopic findings in the chronic stage and to some extent the clinical outcome. Studies of larger clinical groups will be necessary to further elucidate the prognostic potential of proton magnetic resonance spectroscopy in human stroke....

  2. Methylmercury chloride damage to the adult rat hippocampus cannot be detected by proton magnetic resonance spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Zhiyan Lu; Jinwei Wu; Guangyuan Cheng; Jianying Tian; Zeqing Lu; Yongyi Bi

    2014-01-01

    Previous studies have found that methylmercury can damage hippocampal neurons and accord-ingly cause cognitive dysfunction. However, a non-invasive, safe and accurate detection method for detecting hippocampal injury has yet to be developed. This study aimed to detect methylmer-cury-induced damage on hippocampal tissue using proton magnetic resonance spectroscopy. Rats were given a subcutaneous injection of 4 and 2 mg/kg methylmercury into the neck for 50 consecutive days. Water maze and pathology tests confirmed that cognitive function had been impaired and that the ultrastructure of hippocampal tissue was altered after injection. The results of proton magnetic resonance spectroscopy revealed that the nitrogen-acetyl aspartate/creatine, choline complex/creatine and myoinositol/creatine ratio in rat hippocampal tissue were unchanged. Therefore, proton magnetic resonance spectroscopy can not be used to determine structural damage in the adult rat hippocampus caused by methylmercury chloride.

  3. Quantification of N-Acetyl Aspartyl Glutamate in Human Brain using Proton Magnetic Resonance Spectroscopy at 7 T

    Science.gov (United States)

    Elywa, M.

    2015-07-01

    The separation of N-acetyl aspartyl glutamate (NAAG) from N-acetyl aspartate (NAA) and other metabolites, such as glutamate, by in vivo proton magnetic resonance spectroscopy at 7 T is described. This method is based on the stimulated echo acquisition mode (STEAM), with short and long echo time (TE) and allows quantitative measurements of NAAG in the parietal and pregenual anterior cingulate cortex (pgACC) of human brain. Two basesets for the LCModel have been established using nuclear magnetic resonance simulator software (NMR-SIM). Six healthy volunteers (age 25-35 years) have been examined at 7 T. It has been established that NAAG can be separated and quantified in the parietal location and does not get quantified in the pgACC location when using a short echo time, TE = 20 ms. On the other hand, by using a long echo time, TE = 74 ms, NAAG can be quantified in pgACC structures.

  4. Magnetic Nanoparticle Quantitation with Low Frequency Magnetic Fields: Compensating for Relaxation Effects

    Science.gov (United States)

    Weaver, John B.; Zhang, Xiaojuan; Kuehlert, Esra; Toraya-Brown, Seiko; Reeves, Daniel B.; Perreard, Irina M.; Fiering, Steven N.

    2013-01-01

    Quantifying the number of nanoparticles present in tissue is central to many in vivo and in vitro applications. Magnetic nanoparticles can be detected with high sensitivity both in vivo and in vitro using the harmonics of their magnetization produced in a sinusoidal magnetic field. However, relaxation effects damp the magnetic harmonics rendering them of limited use in quantitation. We show that an accurate measure of the number of nanoparticles can be made by correcting for relaxation effects. Correction for relaxation reduced errors of 50% for larger nanoparticles in high relaxation environments to 2%. The result is a method of nanoparticle quantitation capable of in vivo and in vitro applications including histopathology assays, quantitative imaging, drug delivery and thermal therapy preparation. PMID:23867287

  5. Magnetic Resonance Studies of Proton Loss from Carotenoid Radical Cations

    Energy Technology Data Exchange (ETDEWEB)

    Kispert, Lowell D [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Focsan, A Ligia [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Konovalova, Tatyana A [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lawrence, Jesse [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bowman, Michael K [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dixon, David A [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Molnar, Peter [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Deli, Jozsef [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2007-06-11

    Carotenoids, intrinsic components of reaction centers and pigment-protein complexes in photosynthetic membranes, play a photoprotective role and serve as a secondary electron donor. Before optimum use of carotenoids can be made in artificial photosynthetic systems, their robust nature in living materials requires extensive characterization of their electron transfer, radical trapping ability, stability, structure in and on various hosts, and photochemical behavior. Pulsed ENDOR and 2D-HYSCORE studies combined with DFT calculations reveal that photo-oxidation of natural zeaxanthin (I) and violaxanthin (II) on silica-alumina produces not only the carotenoid radical cations (Car•+) but also neutral radicals (#Car•) by proton loss from the methyl groups at positions 5 or 5', and possibly 9 or 9' and 13 or 13'. Notably, the proton loss favored in I at the 5 position by DFT calculations, is unfavorable in II due to the epoxide at the 5, 6 position. DFT calculations predict the isotropic methyl proton couplings of 8-10 MHz for Car•+ which agree with the ENDOR for carotenoid α-conjugated radical cations. Large α-proton hyperfine coupling constants (>10 MHz) determined from HYSCORE are assigned from the DFT calculations to neutral carotenoid radicals. Proton loss upon photolysis was also examined as a function of carotenoid polarity [Lycopene (III) versus 8'-apo-β-caroten-8'-al (IV)]; hydrogen bonding [Lutein (V) versus III]; host [silica-alumina versus MCM-41 molecular sieve]; and substituted metal in MCM-41. Loss of H+ from the 5(5'), 9(9') or 13(13') methyl positions has importance in photoprotection. Photoprotection involves nonphotochemical quenching (NPQ) in which 1Ch1* decays via energy transfer to the carotenoid which returns to the ground state by thermal dissipation; or via electron transfer to form a charge transfer state (I •+…Chl•-), lower in energy than 1Chl*. Formation of I •+ results in bond

  6. Calculation of fusion gain in fast ignition with magnetic target by relativistic electrons and protons

    Directory of Open Access Journals (Sweden)

    A Parvazian

    2010-12-01

    Full Text Available Fast ignition is a new method for inertial confinement fusion (ICF in which the compression and ignition steps are separated. In the first stage, fuel is compressed by laser or ion beams. In the second phase, relativistic electrons are generated by pettawat laser in the fuel. Also, in the second phase 5-35 MeV protons can be generated in the fuel. Electrons or protons can penetrate in to the ultra-dense fuel and deposit their energy in the fuel . More recently, cylindrical rather than spherical fuel chambers with magnetic control in the plasma domain have been also considered. This is called magnetized target fusion (MTF. Magnetic field has effects on relativistic electrons energy deposition rate in fuel. In this work, fast ignition method in cylindrical fuel chambers is investigated and transportation of the relativistic electrons and protons is calculated using MCNPX and FLUKA codes with 0. 25 and 0. 5 tesla magnetic field in single and dual hot spot. Furthermore, the transfer rate of relativistic electrons and high energy protons to the fuel and fusion gain are calculated. The results show that the presence of external magnetic field guarantees higher fusion gain, and relativistic electrons are much more appropriate objects for ignition. MTF in dual hot spot can be considered as an appropriate substitution for the current ICF techniques.

  7. Amide Proton Transfer (APT) MR imaging and Magnetization Transfer (MT) MR imaging of pediatric brain development

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hong; Kang, Huiying; Peng, Yun [Beijing Children' s Hospital, Capital Medical University, Imaging Center, Department of Radiology, Beijing (China); Zhao, Xuna [Philips Healthcare, Beijing (China); Jiang, Shanshan; Zhang, Yi; Zhou, Jinyuan [Johns Hopkins University, Division of MR Research, Department of Radiology, Baltimore, MD (United States)

    2016-10-15

    To quantify the brain maturation process during childhood using combined amide proton transfer (APT) and conventional magnetization transfer (MT) imaging at 3 Tesla. Eighty-two neurodevelopmentally normal children (44 males and 38 females; age range, 2-190 months) were imaged using an APT/MT imaging protocol with multiple saturation frequency offsets. The APT-weighted (APTW) and MT ratio (MTR) signals were quantitatively analyzed in multiple brain areas. Age-related changes in MTR and APTW were evaluated with a non-linear regression analysis. The APTW signals followed a decreasing exponential curve with age in all brain regions measured (R{sup 2} = 0.7-0.8 for the corpus callosum, frontal and occipital white matter, and centrum semiovale). The most significant changes appeared within the first year. At maturation, larger decreases in APTW and lower APTW values were found in the white matter. On the contrary, the MTR signals followed an increasing exponential curve with age in the same brain regions measured, with the most significant changes appearing within the initial 2 years. There was an inverse correlation between the MTR and APTW signal intensities during brain maturation. Together with MT imaging, protein-based APT imaging can provide additional information in assessing brain myelination in the paediatric population. (orig.)

  8. Molecular dynamics simulations of proton transverse relaxation times in suspensions of magnetic nanoparticles.

    Science.gov (United States)

    Panczyk, Tomasz; Konczak, Lukasz; Zapotoczny, Szczepan; Szabelski, Pawel; Nowakowska, Maria

    2015-01-01

    In this work we have analyzed the influence of various factors on the transverse relaxation times T2 of water protons in suspension of magnetic nanoparticles. For that purpose we developed a full molecular dynamics force field which includes the effects of dispersion interactions between magnetic nanoparticles and water molecules, electrostatic interactions between charged nanoparticles and magnetic dipole-dipole and dipole-external field interactions. We also accounted for the magnetization reversal within the nanoparticles body frames due to finite magnetic anisotropy barriers. The force field together with the Langevin dynamics imposed on water molecules and the nanoparticles allowed us to monitor the dephasing of water protons in real time. Thus, we were able to determine the T2 relaxation times including the effects of the adsorption of water on the nanoparticles' surfaces, thermal fluctuations of the orientation of nanoparticles' magnetizations as well as the effects of the core-shell architecture of nanoparticles and their agglomeration into clusters. We found that there exists an optimal cluster size for which T2 is minimized and that the retardation of water molecules motion, due to adsorption on the nanoparticles surfaces, has some effect in the measured T2 times. The typical strengths of the external magnetic fields in MRI are enough to keep the magnetizations fixed along the field direction, however, in the case of low magnetic fields, we observed significant enhancement of T2 due to thermal fluctuations of the orientations of magnetizations. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Quantitative analysis of cyclic dimer fatty acid content in the dimerization product by proton NMR spectroscopy.

    Science.gov (United States)

    Park, Kyun Joo; Kim, Minyoung; Seok, Seunghwan; Kim, Young-Wun; Kim, Do Hyun

    2015-01-01

    In this work, (1)H NMR is utilized for the quantitative analysis of a specific cyclic dimer fatty acid in a dimer acid mixture using the pseudo-standard material of mesitylene on the basis of its structural similarity. Mesitylene and cyclic dimer acid levels were determined using the signal of the proton on the cyclic ring (δ=6.8) referenced to the signal of maleic acid (δ=6.2). The content of the cyclic dimer fatty acid was successfully determined through the standard curve of mesitylene and the reported equation. Using the linearity of the mesitylene curve, the cyclic dimer fatty acid in the oil mixture was quantified. The results suggest that the proposed method can be used to quantify cyclic compounds in mixtures to optimize the dimerization process.

  10. Megalencephalic leukoencephalopathy with subcortical cysts in an adult: quantitative proton MR spectroscopy and diffusion tensor MRI

    Energy Technology Data Exchange (ETDEWEB)

    Brockmann, K.; Hanefeld, F. [Dept. of Paediatrics and Neuropaediatrics, Children' s Hospital, Georg-August-Univ., Goettingen (Germany); Finsterbusch, J.; Frahm, J. [Biomedizinische NMR Forschungs GmbH am Max-Planck-Inst. fuer biophysikalische Chemie, Goettingen (Germany); Terwey, B. [Inst. fuer Magnet-Resonanz-Diagnostik, Zentralkrankenhaus, Bremen (Germany)

    2003-03-01

    A 37-year-old macrocephalic woman was investigated for increasing gait disturbance due to longstanding spasticity and ataxia. MRI showed widespread bilateral increase in signal from cerebral white matter on T2-weighted images. Numerous subcortical cysts were visible in anterior-temporal and parietal regions. These clinical and neuroradiological features are those of megalencephalic leukoencephalopathy with subcortical cysts (MLC), a recently delineated white-matter disease with onset in childhood. Quantitative localised proton MR spectroscopy of white matter revealed marked reduction of N-acetylaspartate, creatine, and choline with normal values for myoinositol, consistent with axonal loss and astrocytic proliferation. Diffusion tensor imaging showed an increased apparent diffusion coefficient and reduced anisotropy in affected white matter pointing to reduced cell density with an increased extracellular space. These findings are in line with histological changes alterations known to occur in MLC. (orig.)

  11. Magnetically scanned proton therapy beams: rationales and principles

    Science.gov (United States)

    Jones, D. T. L.; Schreuder, A. N.

    2001-06-01

    High-energy proton therapy is finding increased application in radiation oncology because of the unique physical characteristics of proton beams which allow superior conformation of the high-dose region to the target volume. The standard method of "painting" the required dose over the target volume is to use passive mechanical means involving multiple scattering and variable thickness absorbers. However, this technique dose not allow proximal surface dose conformation which can only be achieved using beam scanning techniques. Apart from reducing the integral dose, intensity modulation and inverse planning are possible, there is less activation of the surroundings and no field-specific modification devices are required. However, scanning systems are very complicated and there are very high instantaneous dose rates which require sophisticated control systems.

  12. Magnetic dipole moment of the doubly closed-shell plus one proton nucleus $^{49}$Sc

    CERN Multimedia

    Gaulard, C V; Walters, W; Nishimura, K; Muto, S; Bingham, C R

    It is proposed to measure the magnetic moment of $^{49}$Sc by the Nuclear Magnetic Resonance on Oriented Nuclei (NMR-ON) method using the NICOLE on-line nuclear orientation facility. $^{49}$Sc is the neutron rich, doubly closed-shell, nucleus $^{48}$Ca plus one proton. Results will be used to deduce the effective g-factors in the $^{48}$Ca region with reference to nuclear structure and meson exchange current effects.

  13. In Situ Characterisation of Permanent Magnetic Quadrupoles for focussing proton beams

    CERN Document Server

    Melone, J J; McCanny, T; Burris-Mog, T; Schramm, U; Grötschel, R; Akhmadaliev, S; Hanf, D; Spohr, K M; Bussmann, M; Cowan, T; Wiggins, S M; Mitchell, M R

    2011-01-01

    High intensity laser driven proton beams are at present receiving much attention. The reasons for this are many but high on the list is the potential to produce compact accelerators. However two of the limitations of this technology is that unlike conventional nuclear RF accelerators lasers produce diverging beams with an exponential energy distribution. A number of different approaches have been attempted to monochromise these beams but it has become obvious that magnetic spectrometer technology developed over many years by nuclear physicists to transport and focus proton beams could play an important role for this purpose. This paper deals with the design and characterisation of a magnetic quadrupole system which will attempt to focus and transport laser-accelerated proton beams.

  14. The origin of lactate in peritumoral edema as measured by proton-magnetic resonance spectroscopic imaging

    NARCIS (Netherlands)

    Go, Kian; Krikke, AP; Kamman, RL; Heesters, Martinus; James, HE; Marshall, LF; Reulen, HJ; Baethmann, A; Marmarou, A; Ito, U; Hoff, JT; Kuroiwa, T; Czernicki, Z

    1997-01-01

    Using in vivo proton-magnetic resonance spectroscopy (H-1-MRS), which allows the measurement of metabolites of adequate tissue concentration, the origin of lactate in peritumoral edema has been assessed by comparison with lactate levels in the central and marginal areas of the tumor in 18 patients w

  15. The origin of lactate in peritumoral edema as measured by proton-magnetic resonance spectroscopic imaging

    NARCIS (Netherlands)

    Go, Kian; Krikke, AP; Kamman, RL; Heesters, Martinus; James, HE; Marshall, LF; Reulen, HJ; Baethmann, A; Marmarou, A; Ito, U; Hoff, JT; Kuroiwa, T; Czernicki, Z

    1997-01-01

    Using in vivo proton-magnetic resonance spectroscopy (H-1-MRS), which allows the measurement of metabolites of adequate tissue concentration, the origin of lactate in peritumoral edema has been assessed by comparison with lactate levels in the central and marginal areas of the tumor in 18 patients

  16. Internal Field of Homogeneously Magnetized Toroid Sensor for Proton Free Precession Magnetometer

    DEFF Research Database (Denmark)

    Primdahl, Fritz; Merayo, José M.G.; Brauer, Peter

    2005-01-01

    The shift of the NMR spectral line frequency in a proton free precession absolute scalar magnetometer using the omni-directional toroid container for a proton-rich liquid depends on the magnetic susceptibility of the liquid and on the direction of the external field relative to the axis of the to......The shift of the NMR spectral line frequency in a proton free precession absolute scalar magnetometer using the omni-directional toroid container for a proton-rich liquid depends on the magnetic susceptibility of the liquid and on the direction of the external field relative to the axis...... of the toroid. The theoretical shift is estimated for water by computing the additional magnetic field from the magnetization of the liquid and comparing it to the theoretical field in a spherical container. Along the axis the estimated average shift is -0.08 nT and perpendicular to the axis the shift is +0.......08 nT relative to that of a spherical sensor. The field inhomogeneity introduced by the toroid shape amounts to 0.32 nT over the volume of the sensor and is not expected to significantly affect the signal decay time, when considering the typical water line width of about 2.5 InT....

  17. The Strange Magnetic Moment of the Proton in the Chiral Quark Model

    OpenAIRE

    1998-01-01

    The strange magnetic moment of the proton is small in the chiral quark model, because of a near cancellation between the quantum fluctuations that involve kaons and $s$-quarks and loops that involve radiative transitions between strange vector mesons and kaons.

  18. Quantum Field Theoretic Treatment of Pion Production via Proton Synchrotron Radiation in Strong Magnetic Fields: Effects of Landau Levels

    CERN Document Server

    Maruyama, Tomoyuki; Kajino, Toshitaka; Kwon, Yongshin; Mathews, Grant J; Ryu, Chung-Yeol

    2015-01-01

    We study pion production from proton synchrotron radiation in the presence of strong magnetic fields. We derive the exact proton propagator from the Dirac equation in a strong magnetic field by explicitly including the anomalous magnetic moment. In this exact quantum-field approach the magnitude of pion synchrotron emission turns out to be much smaller than that obtained in the semi-classical approach. However, we also find that the anomalous magnetic moment of the proton greatly enhances the production rate about by two order magnitude.

  19. Double resonance experiments in low magnetic field: dynamic polarization of protons by (14)N and measurement of low NQR frequencies.

    Science.gov (United States)

    Seliger, J; Zagar, V

    2009-08-01

    The possibilities of dynamically polarizing proton spin system via the quadrupole (14)N spin system in low magnetic field are analyzed. The increase of the proton magnetization is calculated. The polarization rate of the proton spin system is related to the transition probabilities per unit time between the (14)N quadrupole energy levels and proton energy levels. The experiments performed in 1,3,5-triazine confirm the results of the theoretical analysis. A new double resonance technique is proposed for the measurement of nuclear quadrupole resonance frequencies nu(Q) of the order of 100kHz and lower. The technique is based on magnetic field cycling between a high and a low static magnetic field and observation of the proton NMR signal in the high magnetic field. In the low magnetic field the quadrupole nuclei and protons resonantly interact at the proton Larmor frequency nu(H)=nu(Q)/2. The quadrupole nuclei are simultaneously excited by a resonant rf magnetic field oriented along the direction of the low static magnetic field. The experimental procedure is described and the sensitivity of the new technique is estimated. Some examples of the measurement of low (14)N and (2)H nuclear quadrupole resonance frequencies are presented.

  20. Quantitative metal magnetic memory reliability modeling for welded joints

    Science.gov (United States)

    Xing, Haiyan; Dang, Yongbin; Wang, Ben; Leng, Jiancheng

    2016-03-01

    Metal magnetic memory(MMM) testing has been widely used to detect welded joints. However, load levels, environmental magnetic field, and measurement noises make the MMM data dispersive and bring difficulty to quantitative evaluation. In order to promote the development of quantitative MMM reliability assessment, a new MMM model is presented for welded joints. Steel Q235 welded specimens are tested along the longitudinal and horizontal lines by TSC-2M-8 instrument in the tensile fatigue experiments. The X-ray testing is carried out synchronously to verify the MMM results. It is found that MMM testing can detect the hidden crack earlier than X-ray testing. Moreover, the MMM gradient vector sum K vs is sensitive to the damage degree, especially at early and hidden damage stages. Considering the dispersion of MMM data, the K vs statistical law is investigated, which shows that K vs obeys Gaussian distribution. So K vs is the suitable MMM parameter to establish reliability model of welded joints. At last, the original quantitative MMM reliability model is first presented based on the improved stress strength interference theory. It is shown that the reliability degree R gradually decreases with the decreasing of the residual life ratio T, and the maximal error between prediction reliability degree R 1 and verification reliability degree R 2 is 9.15%. This presented method provides a novel tool of reliability testing and evaluating in practical engineering for welded joints.

  1. Development of a compact magnetic proton recoil spectrometer for measurement of deuterium-tritium neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jianfu, E-mail: zhangjfu@gmail.com; Ouyang, Xiaoping; Zhang, Xianpeng [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Northwest Institute of Nuclear Technology, Xi’an 710024 (China); Qiu, Suizheng, E-mail: szqiu@mail.xjtu.edu.cn [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Zhang, Guoguang [Applied Institute of Nuclear Technology, China Institute of Atomic Energy, Beijing 102413 (China); Ruan, Jinlu; Zhang, Xiaodong; Yang, Shaohua; Song, Jiwen; Liu, Linyue; Li, Hongyun [Northwest Institute of Nuclear Technology, Xi’an 710024 (China)

    2015-12-15

    A new compact magnetic proton recoil (MPR) neutron spectrometer has been designed for precise measurement of deuterium-tritium (DT) neutrons. This design is presented emphasizing the magnetic analyzing system, which is based on a compact quadrupole-dipole (QD) electromagnet. The focal plane detector (FPD) is also discussed with respect to application for the next step. The characteristics of the MPR spectrometer were calculated by using Monte Carlo simulation. A preliminary experiment was performed to test the magnetic analyzing system and the proton images of the FPD. Since the QD electromagnet design allows for a larger foil thickness and solid angle to be utilized, the MPR spectrometer defined in this paper can achieve neutron detection efficiency more than 5 × 10{sup −7} at an energy resolution of 1.5% for measuring DT neutrons.

  2. Magnetic fluctuation power near proton temperature anisotropy instability thresholds in the solar wind

    CERN Document Server

    Bale, S D; Howes, G G; Quataert, E; Salem, C; Sundkvist, D

    2009-01-01

    The proton temperature anisotropy in the solar wind is known to be constrained by the theoretical thresholds for pressure anisotropy-driven instabilities. Here we use approximately 1 million independent measurements of gyroscale magnetic fluctuations in the solar wind to show for the first time that these fluctuations are enhanced along the temperature anisotropy thresholds of the mirror, proton oblique firehose, and ion cyclotron instabilities. In addition, the measured magnetic compressibility is enhanced at high plasma beta ($\\beta_\\parallel \\gtrsim 1$) along the mirror instability threshold but small elsewhere, consistent with expectations of the mirror mode. The power in this frequency (the 'dissipation') range is often considered to be driven by the solar wind turbulent cascade, an interpretation which should be qualified in light of the present results. In particular, we show that the short wavelength magnetic fluctuation power is a strong function of collisionality, which relaxes the temperature aniso...

  3. Pulsed high field magnets. An efficient way of shaping laser accelerated proton beams for application

    Energy Technology Data Exchange (ETDEWEB)

    Kroll, Florian; Schramm, Ulrich [Helmholtz-Zentrum Dresden - Rossendorf, 01328 Dresden (Germany); Technische Universitaet Dresden, 01062 Dresden (Germany); Bagnoud, Vincent; Blazevic, Abel; Busold, Simon [GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Helmholtz Institut Jena, 07734 Jena (Germany); Brabetz, Christian; Schumacher, Dennis [GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Deppert, Oliver; Jahn, Diana; Roth, Markus [Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Karsch, Leonhard; Masood, Umar [OncoRay-National Center for Radiation Research in Oncology, TU Dresden, 01307 Dresden (Germany); Kraft, Stephan [Helmholtz-Zentrum Dresden - Rossendorf, 01328 Dresden (Germany)

    2015-07-01

    Compact laser-driven proton accelerators are a potential alternative to complex, expensive conventional accelerators, enabling unique beam properties, like ultra-high pulse dose. Nevertheless, they still require substantial development in reliable beam generation and transport. We present experimental studies on capture, shape and transport of laser and conventionally accelerated protons via pulsed high-field magnets. These magnets, common research tools in the fields of solid state physics, have been adapted to meet the demands of laser acceleration experiments.Our work distinctively shows that pulsed magnet technology makes laser acceleration more suitable for application and can facilitate compact and efficient accelerators, e.g. for material research as well as medical and biological purposes.

  4. Magnet Design for the ISIS Second Target Station Proton Beam Line

    CERN Document Server

    Thomas, Chris; Jago, Stephen

    2005-01-01

    The ISIS facility, based at the Rutherford Appleton Laboratory in the UK, is an intense source of neutrons and muons for condensed matter research. The accelerator facility delivers an 800 MeV proton beam of 2.5x1013 protons per pulse at 50 Hz to the present target station. As part of a facility upgrade, it is planned to share the source with a second, 10 Hz, target station. The beam line supplying this target will extract from the existing target station beam line. Electromagnetic Finite Element Modelling techniques have been used to design the magnets required to meet the specified beam line optics. Kicker, septum, dipole, quadrupole, and steering magnets are covered. The magnet design process, involving 2D and 3D modelling, the calculation of ideal shims and chamfers, choice of steel, design of conducting coils, handling of heating issues and eddy current effects, is discussed.

  5. A design study of a magnifying magnetic lens for proton radiography

    Institute of Scientific and Technical Information of China (English)

    YANG Guo-Jun; ZHANG Zhuo; WEI Tao; HE Xiao-Zhong; LONG Ji-Dong; SHI Jin-Shui; ZHANG Kai-Zhi

    2012-01-01

    Magnifying magnetic lenses can be used in high-energy proton microscopes.The -I lens suggested by Zumbro is analyzed in this paper,and a new type of magnetic lens called a lengthened lens is introduced.Theoretical analysis shows that the lengthened lens can form a magnifying lens,and at the same time the main advantages of a Zumbro lens are inherited.Using the My-BOC beam dynamics code,an example of the design is shown.The results show that the method of designing magnifying magnetic lenses is effective.

  6. An algorithm for predicting proton nuclear magnetic resonance deshielding over a carbon-carbon double bond.

    Science.gov (United States)

    Martin, N H; Allen, N W; Brown, J D; Ingrassia, S T; Minga, E K

    2000-02-01

    Hydrogen nuclei located over a carbon-carbon double bond in a strong magnetic field experience NMR shielding effects that result from the magnetic anisotropy of the nearby double bond and various other intramolecular shielding effects. We have used GIAO, a subroutine in Gaussian 98, to calculate isotropic shielding values and to predict the proton NMR shielding increment for a simple model system: methane held in various orientations, positions, and distances over ethene. The average proton NMR shielding increments of several orientations of methane have been plotted versus the Cartesian coordinates of the methane protons relative to the center of ethene. A single empirical equation for predicting the NMR shielding experienced by protons over a carbon-carbon double bond has been developed from these data. The predictive capability of this equation has been validated by comparing the shielding increments for several alkenes calculated using our equation to the experimentally observed shielding increments. This equation predicts the NMR shielding effects more accurately than previous models that were based on fewer geometries of methane over ethene. In fact, deshielding is predicted by this equation for protons over the center and within about 3 A of a carbon-carbon double bond. This result is in sharp contrast to predictions made by the long-held McConnell "shielding cone" model found in nearly every textbook on NMR, but is consistent with experimental observations. The algorithm for predicting the (de)shielding increment for a proton over an alkene can be used in a spreadsheet on a PC or incorporated into software that estimates chemical shifts using additive substituent constants or a database of structures. In either application its use can substantially improve the accuracy of the estimated chemical shift of a proton in the vicinity of a carbon-carbon double bond, and thus assist in spectral assignments and in correct structure determination.

  7. Proton entry into the near-lunar plasma wake for magnetic field aligned flow

    CERN Document Server

    Dhanya, M B; Futaana, Y; Fatemi, S; Holmström, M; Barabash, S; Wieser, M; Wurz, P; Alok, A; Thampi, R S

    2016-01-01

    We report the first observation of protons in the near (100--200 km from surface) and deeper (near anti-subsolar point) lunar plasma wake when the interplanetary magnetic field (IMF) and solar wind velocity ($v_{sw}$) are parallel (aligned flow, angle between IMF and ($v_{sw} \\le 10^\\circ$). More than 98% of the observations during aligned flow condition showed the presence of protons in the wake. These observations are obtained by the SWIM sensor of the SARA experiment on Chandrayaan-1. The observation cannot be explained by the conventional fluid models for aligned flow. Back-tracing of the observed protons suggests that their source is the solar wind. The larger gyro-radii of the wake protons compared to that of solar wind suggest that they were part of the tail of the solar wind velocity distribution function. Such protons could enter the wake due to their large gyro-radii even when the flow is aligned to IMF. However, the wake boundary electric field may also play a role in the entry of the protons in to...

  8. Quantitative magnetic resonance imaging of cortical multiple sclerosis pathology

    DEFF Research Database (Denmark)

    Tardif, Christine L; Bedell, Barry J; Eskildsen, Simon Fristed

    2012-01-01

    pathology. The objective of this study was to characterize the MRI signature of CLs to help interpret the changes seen in vivo and elucidate the factors limiting their visualization. A quantitative 3D high-resolution (350 μm isotropic) MRI study at 3 Tesla of a fixed post mortem cerebral hemisphere from......Although significant improvements have been made regarding the visualization and characterization of cortical multiple sclerosis (MS) lesions using magnetic resonance imaging (MRI), cortical lesions (CL) continue to be under-detected in vivo, and we have a limited understanding of the causes of GM...... a patient with MS is presented in combination with matched immunohistochemistry. Type III subpial lesions are characterized by an increase in T1, T2 and M0, and a decrease in MTR in comparison to the normal appearing cortex (NAC). All quantitative MR parameters were associated with cortical GM myelin...

  9. Motor-Generator powering the PS (Proton Synchrotron) main magnets

    CERN Multimedia

    1983-01-01

    This motor-generator,30 MW peak, 1500 r.p.m.,pulsed power supply for the PS main magnet replaced in 1968 the initial 3000 r.p.m. motor-generator-flywheel set which had served from the PS start-up in 1959 until end 1967. See also photo 8302337 and its abstract.

  10. Quantitative, comprehensive, analytical model for magnetic reconnection in Hall magnetohydrodynamics.

    Science.gov (United States)

    Simakov, Andrei N; Chacón, L

    2008-09-05

    Dissipation-independent, or "fast", magnetic reconnection has been observed computationally in Hall magnetohydrodynamics (MHD) and predicted analytically in electron MHD. However, a quantitative analytical theory of reconnection valid for arbitrary ion inertial lengths, d{i}, has been lacking and is proposed here for the first time. The theory describes a two-dimensional reconnection diffusion region, provides expressions for reconnection rates, and derives a formal criterion for fast reconnection in terms of dissipation parameters and d{i}. It also confirms the electron MHD prediction that both open and elongated diffusion regions allow fast reconnection, and reveals strong dependence of the reconnection rates on d{i}.

  11. Quantitative Magnetic Separation of Particles and Cells Using Gradient Magnetic Ratcheting.

    Science.gov (United States)

    Murray, Coleman; Pao, Edward; Tseng, Peter; Aftab, Shayan; Kulkarni, Rajan; Rettig, Matthew; Di Carlo, Dino

    2016-04-13

    Extraction of rare target cells from biosamples is enabling for life science research. Traditional rare cell separation techniques, such as magnetic activated cell sorting, are robust but perform coarse, qualitative separations based on surface antigen expression. A quantitative magnetic separation technology is reported using high-force magnetic ratcheting over arrays of magnetically soft micropillars with gradient spacing, and the system is used to separate and concentrate magnetic beads based on iron oxide content (IOC) and cells based on surface expression. The system consists of a microchip of permalloy micropillar arrays with increasing lateral pitch and a mechatronic device to generate a cycling magnetic field. Particles with higher IOC separate and equilibrate along the miropillar array at larger pitches. A semi-analytical model is developed that predicts behavior for particles and cells. Using the system, LNCaP cells are separated based on the bound quantity of 1 μm anti-epithelial cell adhesion molecule (EpCAM) particles as a metric for expression. The ratcheting cytometry system is able to resolve a ±13 bound particle differential, successfully distinguishing LNCaP from PC3 populations based on EpCAM expression, correlating with flow cytometry analysis. As a proof-of-concept, EpCAM-labeled cells from patient blood are isolated with 74% purity, demonstrating potential toward a quantitative magnetic separation instrument.

  12. New method to determine proton trajectories in the equatorial plane of a dipole magnetic field.

    Science.gov (United States)

    Ioanoviciu, Damaschin

    2015-01-01

    A parametric description of proton trajectories in the equatorial plane of Earth's dipole magnetic field has been derived. The exact expression of the angular coordinate contains an integral to be performed numerically. The radial coordinate results from the initial conditions by basic mathematical operations and by using trigonometric functions. With the approximate angular coordinate formula, applicable for a wide variety of cases of protons trapped in Earth's radiation belts, no numerical integration is needed. The results of exact and approximate expressions were compared for a specific case and small differences were found.

  13. Dry-cured ham tissue characterization by fast field cycling NMR relaxometry and quantitative magnetization transfer.

    Science.gov (United States)

    Bajd, Franci; Gradišek, Anton; Apih, Tomaž; Serša, Igor

    2016-05-31

    Fast field cycling (FFC) and quantitative magnetization transfer (qMT) NMR methods are two powerful tools in NMR analysis of biological tissues. The qMT method is well established in biomedical NMR applications, while the FFC method is often used in investigations of molecular dynamics on which longitudinal NMR relaxation times of the investigated material critically depend. Despite their proven analytical potential, these two methods were rarely used in NMR studies of food, especially when combined together. In our study, we demonstrate the feasibility of a combined FFC/qMT-NMR approach for the fast and nondestructive characterization of dry-curing ham tissues differing by protein content. The characterization is based on quantifying the pure quadrupolar peak area (area under the quadrupolar contribution of dispersion curve obtained by FFC-NMR) and the restricted magnetization pool size (obtained by qMT-NMR). Both quantities correlate well with concentration of partially immobilized, nitrogen-containing and proton magnetization exchanging muscle proteins. Therefore, these two quantities could serve as potential markers for dry-curing process monitoring. Copyright © 2016 John Wiley & Sons, Ltd.

  14. Short- and long-term quantitation reproducibility of brain metabolites in the medial wall using proton echo planar spectroscopic imaging.

    Science.gov (United States)

    Tsai, Shang-Yueh; Lin, Yi-Ru; Wang, Woan-Chyi; Niddam, David M

    2012-11-15

    Proton echo planar spectroscopic imaging (PEPSI) is a fast magnetic resonance spectroscopic imaging (MRSI) technique that allows mapping spatial metabolite distributions in the brain. Although the medial wall of the cortex is involved in a wide range of pathological conditions, previous MRSI studies have not focused on this region. To decide the magnitude of metabolic changes to be considered significant in this region, the reproducibility of the method needs to be established. The study aims were to establish the short- and long-term reproducibility of metabolites in the right medial wall and to compare regional differences using a constant short-echo time (TE30) and TE averaging (TEavg) optimized to yield glutamatergic information. 2D sagittal PEPSI was implemented at 3T using a 32 channel head coil. Acquisitions were repeated immediately and after approximately 2 weeks to assess the coefficients of variation (COV). COVs were obtained from eight regions-of-interest (ROIs) of varying size and location. TE30 resulted in better spectral quality and similar or lower quantitation uncertainty for all metabolites except glutamate (Glu). When Glu and glutamine (Gln) were quantified together (Glx) reduced quantitation uncertainty and increased reproducibility was observed for TE30. TEavg resulted in lowered quantitation uncertainty for Glu but in less reliable quantification of several other metabolites. TEavg did not result in a systematically improved short- or long-term reproducibility for Glu. The ROI volume was a major factor influencing reproducibility. For both short- and long-term repetitions, the Glu COVs obtained with TEavg were 5-8% for the large ROIs, 12-17% for the medium sized ROIs and 16-26% for the smaller cingulate ROIs. COVs obtained with TE30 for the less specific Glx were 3-5%, 8-10% and 10-15%. COVs for N-acetyl aspartate, creatine and choline using TE30 with long-term repetition were between 2-10%. Our results show that the cost of more specific

  15. Quantitative in vivo magnetic resonance spectroscopy using synthetic signal injection.

    Directory of Open Access Journals (Sweden)

    Kenneth I Marro

    Full Text Available Accurate conversion of magnetic resonance spectra to quantitative units of concentration generally requires compensation for differences in coil loading conditions, the gains of the various receiver amplifiers, and rescaling that occurs during post-processing manipulations. This can be efficiently achieved by injecting a precalibrated, artificial reference signal, or pseudo-signal into the data. We have previously demonstrated, using in vitro measurements, that robust pseudo-signal injection can be accomplished using a second coil, called the injector coil, properly designed and oriented so that it couples inductively with the receive coil used to acquire the data. In this work, we acquired nonlocalized phosphorous magnetic resonance spectroscopy measurements from resting human tibialis anterior muscles and used pseudo-signal injection to calculate the Pi, PCr, and ATP concentrations. We compared these results to parallel estimates of concentrations obtained using the more established phantom replacement method. Our results demonstrate that pseudo-signal injection using inductive coupling provides a robust calibration factor that is immune to coil loading conditions and suitable for use in human measurements. Having benefits in terms of ease of use and quantitative accuracy, this method is feasible for clinical use. The protocol we describe could be readily translated for use in patients with mitochondrial disease, where sensitive assessment of metabolite content could improve diagnosis and treatment.

  16. Determination of Magnet Specification of 13 MeV Proton Cyclotron Based on Opera 3D

    Directory of Open Access Journals (Sweden)

    Taufik

    2014-08-01

    Full Text Available The magnet is one of the main components of a cyclotron, used to form a circular particle beam trajectories and to provide focusing of the beam. To support the mastery of 13-MeV proton cyclotron technologies, cyclotron magnet design must be done to satisfy cyclotron magnet requirements. This research was conducted by studying important parameters in designing the cyclotron magnet which is then used to determine the design requirements. The magnet design was based on the results of a 3D simulation using Opera 3D software. Opera 3D is a software developed by Cobham plc to solve physical problems in 3D such as magnetostatic using finite element methods. The simulation started by drawing a 3D model of the magnet using a modeler, followed by magnetic field calculations by Tosca module in the Opera 3D software. Simulation results were analyzed with the Genspeo software to determine whether the parameters of the cyclotron magnet have met design requirements. The results indicate that the magnet design satisfied the cyclotron magnet design requirement, that B in the median plane of the magnetic pole approached the isochronous curve, providing axial and radial focusing beam, crossing the resonance line at vr = 1 when the particle energy is low and the particle energy is more than 13 MeV, and lead to small enough phase shift of about 13°. The dimension of the cyclotron magnet is 1.96 m × 1.30 m × 1.21 m; its weight is 17.3 ton; its coil current is 88,024 ampere-turn; its center magnetic field is 1.27479 T; its maximum magnetic field is 1.942116 T; its minimum magnetic field is 0.7689 T; its valley gap is 120 mm; its hill gaps are 40 to 50.78 mm; and its hill angles are 35° to 44°.to 44°

  17. SU-D-304-02: Magnetically Focused Proton Irradiation of Small Field Targets

    Energy Technology Data Exchange (ETDEWEB)

    McAuley, GA; Slater, JM [Loma Linda University, Loma Linda, CA (United States); Slater, JD; Wroe, AJ [Loma Linda University Medical Center, Loma Linda, CA (United States)

    2015-06-15

    Purpose: To investigate the use of magnetic focusing for small field proton irradiations. It is hypothesized that magnetic focusing will provide significant dose distribution benefits over standard collimated beams for fields less than 10 mm diameter. Methods: Magnets consisting of 24 segments of radiation hard samarium-cobalt adhered into hollow cylinders were designed and manufactured. Two focusing magnets were placed on a positioning track on our Gantry 1 treatment table. Proton beams with energies of 127 and 157 MeV, 15 and 30 mm modulation, and 8 mm initial diameters were delivered to a water tank using single-stage scattering. Depth dose distributions were measured using a PTW PR60020 diode detector and transverse profiles were measured with Gafchromic EBT3 film. Monte Carlo simulations were also performed - both for comparison with experimental data and to further explore the potential of magnetic focusing in silica. For example, beam spot areas (based on the 90% dose contour) were matched at Bragg depth between simulated 100 MeV collimated beams and simulated beams focused by two 400 T/m gradient magnets. Results: Preliminary experimental results show 23% higher peak to entrance dose ratios and flatter spread out Bragg peak plateaus for 8 mm focused beams compared with uncollimated beams. Monte Carlo simulations showed 21% larger peak to entrance ratios and a ∼9 fold more efficient dose to target delivery compared to spot-sized matched collimated beams. Our latest results will be presented. Conclusion: Our results suggest that rare earth focusing magnet assemblies could reduce skin dose and beam number while delivering dose to nominally spherical radiosurgery targets over a much shorter time compared to unfocused beams. Immediate clinical applications include those associated with proton radiosurgery and functional radiosurgery of the brain and spine, however expanded treatment sites can be also envisaged.

  18. Modeling the Earth's radiation belts. A review of quantitative data based electron and proton models

    Science.gov (United States)

    Vette, J. I.; Teague, M. J.; Sawyer, D. M.; Chan, K. W.

    1979-01-01

    The evolution of quantitative models of the trapped radiation belts is traced to show how the knowledge of the various features has developed, or been clarified, by performing the required analysis and synthesis. The Starfish electron injection introduced problems in the time behavior of the inner zone, but this residue decayed away, and a good model of this depletion now exists. The outer zone electrons were handled statistically by a log normal distribution such that above 5 Earth radii there are no long term changes over the solar cycle. The transition region between the two zones presents the most difficulty, therefore the behavior of individual substorms as well as long term changes must be studied. The latest corrections to the electron environment based on new data are outlined. The proton models have evolved to the point where the solar cycle effect at low altitudes is included. Trends for new models are discussed; the feasibility of predicting substorm injections and solar wind high-speed streams make the modeling of individual events a topical activity.

  19. Modeling the Earth's radiation belts. A review of quantitative data based electron and proton models

    Science.gov (United States)

    Vette, J. I.; Teague, M. J.; Sawyer, D. M.; Chan, K. W.

    1979-01-01

    The evolution of quantitative models of the trapped radiation belts is traced to show how the knowledge of the various features has developed, or been clarified, by performing the required analysis and synthesis. The Starfish electron injection introduced problems in the time behavior of the inner zone, but this residue decayed away, and a good model of this depletion now exists. The outer zone electrons were handled statistically by a log normal distribution such that above 5 Earth radii there are no long term changes over the solar cycle. The transition region between the two zones presents the most difficulty, therefore the behavior of individual substorms as well as long term changes must be studied. The latest corrections to the electron environment based on new data are outlined. The proton models have evolved to the point where the solar cycle effect at low altitudes is included. Trends for new models are discussed; the feasibility of predicting substorm injections and solar wind high-speed streams make the modeling of individual events a topical activity.

  20. Whole-brain quantitative mapping of metabolites using short echo 3D-proton- MRSI

    Science.gov (United States)

    Lecocq, Angèle; Le Fur, Yann; Maudsley, Andrew A; Le Troter, Arnaud; Sheriff, Sulaiman; Sabati, Mohamad; Donnadieu, Maxime; Confort-Gouny, Sylviane; Cozzone, Patrick J.; Guye, Maxime; Ranjeva, Jean-Philippe

    2014-01-01

    Purpose To improve the extent over which whole brain quantitative 3D-MRSI maps can be obtained and be used to explore brain metabolism in a population of healthy volunteers. Materials and Methods Two short TE (20 ms) acquisitions of 3D Echo Planar Spectroscopic Imaging at two orientations, one in the anterior commissure – posterior commissure (AC-PC) plane and the second tilted in the AC-PC +15° plane were obtained at 3T in a group of ten healthy volunteers. B1+, B1−, and B0 correction procedures and normalization of metabolite signals with quantitative water proton density measurements were performed. A combination of the two spatially normalized 3D-MRSI, using a weighted mean based on the pixel wise standard deviation metabolic maps of each orientation obtained from the whole group, provided metabolite maps for each subject allowing regional metabolic profiles of all parcels of the automated anatomical labeling (AAL) atlas to be obtained. Results The combined metabolite maps derived from the two acquisitions reduced the regional inter-subject variance. The numbers of AAL regions showing NAA SD/Mean ratios lower than 30% increased from 17 in the AC-PC orientation and 41 in the AC-PC+15° orientation, to a value of 76 regions out of 116 for the combined NAA maps. Quantitatively, regional differences in absolute metabolite concentrations (mM) over the whole brain were depicted such as in the GM of frontal lobes (cNAA=10.03+1.71, cCho=1.78±0.55, cCr=7.29±1.69; cmIns=5.30±2.67) and in cerebellum (cNAA=5.28±1.77, cCho=1.60±0.41, cCr=6.95±2.15; cmIns=3.60±0.74). Conclusion A double-angulation acquisition enables improved metabolic characterization over a wide volume of the brain. PMID:25431032

  1. Magnetic properties, water proton relaxivities, and in-vivo MR images of paramagnetic nanoparticles

    Science.gov (United States)

    Lee, Gang Ho; Chang, Yongmin

    2015-07-01

    In this mini review, magnetic resonance imaging (MRI) contrast agents based on lanthanideoxide (Ln2O3) nanoparticles are described. Ln2O3 (Ln = Gd, Dy, Ho, and Er) nanoparticles are paramagnetic, but show appreciable magnetic moments at room temperature and even at ultrasmall particle diameters. Among Ln2O3 nanoparticles, Gd2O3 nanoparticles show larger longitudinal water proton relaxivity (r1) values than Gd-chelates because of the large amount of Gd in the nanoparticle, and the other Ln2O3 nanoparticles (Ln = Dy, Ho, and Er) show appreciable transverse water proton relaxivity (r2) values. Therefore, Gd2O3 nanoparticles are potential T1 MRI contrast agents while the other Ln2O3 nanoparticles are potential T2 MRI contrast agents at high MR fields.

  2. Neurochemical metabolites in the medial prefrontal cortex in bipolar disorder A proton magnetic resonance spectroscopy study

    Institute of Scientific and Technical Information of China (English)

    Osman (O)zdel; Demet Kalayci; Gülfizar S(o)zeri-Varma; Yilmaz Kiro(g)lu; Selim Tümkaya; Tu(g)(c)e Toker-U(g)urlu

    2012-01-01

    The aim of this study was to investigate proton magnetic resonance spectroscopy metabolite values in the medial prefrontal cortex of individuals with euthymic bipolar disorder. The subjects consisted of 15 patients with euthymic bipolar disorder type I and 15 healthy controls. We performed proton magnetic resonance spectroscopy of the bilateral medial prefrontal cortex and measured levels of N-acetyl aspartate, choline and creatine. Levels of these three metabolites in the medial prefrontal cortex were found to be lower in patients with bipolar disorder compared with healthy controls. A positive correlation was found between illness duration and choline levels in the right medial prefrontal cortex. Our study suggests that during the euthymic period, there are abnormalities in cellular energy and membrane phospholipid metabolism in the medial prefrontal cortex, and that this may impair neuronal activity and integrity.

  3. High-field proton magnetic resonance spectroscopy reveals metabolic effects of normal brain aging.

    Science.gov (United States)

    Harris, Janna L; Yeh, Hung-Wen; Swerdlow, Russell H; Choi, In-Young; Lee, Phil; Brooks, William M

    2014-07-01

    Altered brain metabolism is likely to be an important contributor to normal cognitive decline and brain pathology in elderly individuals. To characterize the metabolic changes associated with normal brain aging, we used high-field proton magnetic resonance spectroscopy in vivo to quantify 20 neurochemicals in the hippocampus and sensorimotor cortex of young adult and aged rats. We found significant differences in the neurochemical profile of the aged brain when compared with younger adults, including lower aspartate, ascorbate, glutamate, and macromolecules, and higher glucose, myo-inositol, N-acetylaspartylglutamate, total choline, and glutamine. These neurochemical biomarkers point to specific cellular mechanisms that are altered in brain aging, such as bioenergetics, oxidative stress, inflammation, cell membrane turnover, and endogenous neuroprotection. Proton magnetic resonance spectroscopy may be a valuable translational approach for studying mechanisms of brain aging and pathology, and for investigating treatments to preserve or enhance cognitive function in aging.

  4. NuMI Proton Kicker Extraction Magnet Termination Resistor System

    CERN Document Server

    Reeves, Scott

    2005-01-01

    The temperature stability of the kicker magnet termination resistor assembly directly affects the field flatness and amplitude stability of the kick. Comprehensive thermal enhancements were made to the existing Main Injector resistor assembly design to satisfy NuMI performance specifications. Additionally, a fluid-processing system utilizing Fluorinert® FC-77 high-voltage dielectric was built to precisely control the setpoint temperature of the resistor assembly from 70 to 120F, required to maintain constant resistance during changing operational modes. The Fluorinert® must be continually processed to remove hazardous breakdown products caused by radiation exposure to prevent chemical attack of system components. Design details of the termination resistor assembly and Fluorinert® processing system are described. Early performance results will be presented.

  5. NuMI proton kicker extraction magnet termination resistor system

    Energy Technology Data Exchange (ETDEWEB)

    Reeves, S.R.; Jensen, C.C.; /Fermilab

    2005-05-01

    The temperature stability of the kicker magnet termination resistor assembly directly affects the field flatness and amplitude stability. Comprehensive thermal enhancements were made to the existing Main Injector resistor assembly design to satisfy NuMI performance specifications. Additionally, a fluid-processing system utilizing Fluorinert{reg_sign} FC-77 high-voltage dielectric was built to precisely control the setpoint temperature of the resistor assembly from 70 to 120F, required to maintain constant resistance during changing operational modes. The Fluorinert{reg_sign} must be continually processed to remove hazardous breakdown products caused by radiation exposure to prevent chemical attack of system components. Design details of the termination resistor assembly and Fluorinert{reg_sign} processing system are described. Early performance results will be presented.

  6. Design summary of the magnet support structures for the proton storage ring injection line upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Bernardin, J.D.; Ledford, J.E.; Smith, B.G.

    1997-05-01

    This report summarizes the technical engineering and design issues associated with the Proton Storage Ring (PSR) Injection Line upgrade of the Los Alamos Neutron Science Center (LANSCE). The main focus is on the engineering design calculations of several magnet support structures. The general procedure based upon a set number of design criteria is outlined, followed by a case-by-case summary of the engineering design analyses, reutilization or fabrication callouts and design safety factors.

  7. Thermal Transition of Ribonuclease A Observed Using Proton Nuclear Magnetic Resonance

    Institute of Scientific and Technical Information of China (English)

    闫永彬; 罗雪春; 周海梦; 张日清

    2001-01-01

    The thermal transition of bovine pancreatic ribonuclease A (RNase A) was investigated using proton nuclear magnetic resonance (NMR). Significant resonance overlap in the large native protein limits accurate assignments in the 1H NMR spectrum. This study proposes extending the investigation of large proteins by dynamic analysis. Comparison of the traditional method and the correlation coefficient method suggests successful application of spectrum image analysis in dynamic protein studies by NMR.

  8. Upgrade of the CERN Proton Synchrotron Booster bending magnets for 2 GeV Operation

    CERN Document Server

    Newborough, A; Chritin, R

    2013-01-01

    Since its first operation in 1972 at an energy of 800MeV the CERN Proton Synchrotron Booster, which consists of 4 super imposed synchrotrons, has seen two upgrades: once to 1.0 GeV in 1988 and then to 1.4 GeV in 1999. During this time the main magnets of the machine have remained largely unchanged with small differences (<1%) between the inner and outer gaps of the main bending magnet fields being compensated by trim power supplies. The future upgrade of the machine will demand to extract protons at an energy of 2.0 GeV and require almost double the original dipole field. At this field, due to saturation effects, the inner and outer gaps of the main dipole magnets will differ by up to 4%. This paper presents the design and implementation of a modification of the magnetic circuit strongly reducing these effects. We also discuss the results of experimental tests concerning the effects on field quality and eddy current transients, including the implications for the real-time magnetic field measurement system ...

  9. Medulloblastoma: correlation among findings of conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fonte, Mariana Vieira de Melo da; Otaduy, Maria Concepcion Garcia; Lucato, Leandro Tavares; Reed, Umbertina Conti; Leite, Claudia da Costa [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Inst. de Radiologia]. E-mail: mvmfonte@uol.com.br; Costa, Maria Olivia Rodrigues; Amaral, Raquel Portugal Guimaraes [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Dept. de Radiologia; Reed, Umbertina Conti [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Dept. de Neurologia; Rosemberg, Sergio [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Dept. de Patologia

    2008-11-15

    To correlate imaging findings of medulloblastomas at conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy, comparing them with data in the literature. Preoperative magnetic resonance imaging studies of nine pediatric patients with histologically confirmed medulloblastomas (eight desmoplastic medulloblastoma, and one giant cell medulloblastoma) were retrospectively reviewed, considering demographics as well as tumors characteristics such as localization, morphology, signal intensity, contrast-enhancement, dissemination, and diffusion-weighted imaging and spectroscopy findings. In most of cases the tumors were centered in the cerebellar vermis (77.8%), predominantly solid (88.9%), hypointense on T 1-weighted images and intermediate/hyperintense on T 2-FLAIR-weighted images, with heterogeneous enhancement (100%), tumor dissemination/extension (77.8%) and limited water molecule mobility (100%). Proton spectroscopy acquired with STEAM technique (n = 6) demonstrated decreased Na a / Cr ratio (83.3%) and increased Co/Cr (100%) and ml/Cr (66.7%) ratios; and with PRESS technique (n = 7) demonstrated lactate peak (57.1%). Macroscopic magnetic resonance imaging findings in association with biochemical features of medulloblastomas have been useful in the differentiation among the most frequent posterior fossa tumors. (author)

  10. High Resolution Nuclear Magnetic Resonance Studies of the Active Site of Chymotrypsin. I. The Hydrogen Bonded Protons of the “Charge Relay” System

    NARCIS (Netherlands)

    Robillard, G.; Shulman, R.G.

    1974-01-01

    High resolution proton nuclear magnetic resonance has been used to observe protons at the active site of chymotrypsin Aδ and at the same region of chymotrypsinogen A. A single resonance with the intensity of one proton is located in the low field region of the nuclear magnetic resonance spectrum. Th

  11. Three-dimensional proton magnetic resonance spectroscopic imaging with and without an endorectal coil: a prostate phantom study.

    Science.gov (United States)

    Ma, Chao; Chen, Luguang; Scheenen, Tom W J; Lu, Jianping; Wang, Jian

    2015-11-01

    Proton magnetic resonance spectroscopic imaging (MRSI) of the prostate has been used with only a combination of external surface coils. The quality of spectral fitting of the (choline + creatine)/citrate ([Cho + Cr]/Cit) ratio at different field strengths and different coils is important for quantitative/semi-quantitative diagnosis of prostate cancer. To evaluate the quality of spectral fitting of the (Cho + Cr)/Cit ratio of a prostate phantom using MRSI at different field strengths and various coils. Experiments were using 1.5-T and 3.0-T MR systems. Measurements were taken on a homemade prostate phantom with different coils: spinal array; abdominal array; and endorectal. The signal-to-noise ratio (SNR) of choline, creatine, and citrate peaks as well as the (Cho + Cr)/Cit ratio in each voxel were compared among groups using multi-way analysis of variance. Magnetic field strength, coils, and plane position had a significant effect on the SNR or (Cho + Cr)/Cit ratio, and there were interactions among groups (all P = 0.000). The 1.5-T (0.228 ± 0.044) exhibited a higher (Cho + Cr)/Cit ratio than the 3.0-T (0.125 ± 0.041) magnetic field strength (F = 3238, P = 0.000). The (Cho + Cr)/Cit ratio of both surface coils (0.183 ± 0.065) and all coils (0.181 ± 0.057) was significantly lower than that of the endorectal coil (0.195 ± 0.077) (both P coils and all coils were used (P > 0.05). No significant differences were found among the (Cho + Cr)/Cit ratios of all voxels in the middle planes by the post-hoc analyses (all P > 0.05). Three-dimensional proton MRSI of prostate metabolites in a phantom using surface coils is feasible and reliable, but (Cho + Cr)/Cit ratios acquired at different magnetic fields and coils were different. This difference should be taken into account when calculating this ratio in a field strength-independent way. © The Foundation Acta Radiologica 2014.

  12. Quantitative Magnetic Resonance Imaging of Cortical Multiple Sclerosis Pathology

    Directory of Open Access Journals (Sweden)

    Christine L. Tardif

    2012-01-01

    Full Text Available Although significant improvements have been made regarding the visualization and characterization of cortical multiple sclerosis (MS lesions using magnetic resonance imaging (MRI, cortical lesions (CL continue to be under-detected in vivo, and we have a limited understanding of the causes of GM pathology. The objective of this study was to characterize the MRI signature of CLs to help interpret the changes seen in vivo and elucidate the factors limiting their visualization. A quantitative 3D high-resolution (350 μm isotropic MRI study at 3 Tesla of a fixed post mortem cerebral hemisphere from a patient with MS is presented in combination with matched immunohistochemistry. Type III subpial lesions are characterized by an increase in T1, T2 and M0, and a decrease in MTR in comparison to the normal appearing cortex (NAC. All quantitative MR parameters were associated with cortical GM myelin content, while T1 showed the strongest correlation. The histogram analysis showed extensive overlap between CL and NAC for all MR parameters and myelin content. This is due to the poor contrast in myelin content between CL and NAC in comparison to the variability in myelo-architecture throughout the healthy cortex. This latter comparison is highlighted by the representation of T1 times on cortical surfaces at several laminar depths.

  13. Quantitative analysis of brain magnetic resonance imaging for hepatic encephalopathy

    Science.gov (United States)

    Syh, Hon-Wei; Chu, Wei-Kom; Ong, Chin-Sing

    1992-06-01

    High intensity lesions around ventricles have recently been observed in T1-weighted brain magnetic resonance images for patients suffering hepatic encephalopathy. The exact etiology that causes magnetic resonance imaging (MRI) gray scale changes has not been totally understood. The objective of our study was to investigate, through quantitative means, (1) the amount of changes to brain white matter due to the disease process, and (2) the extent and distribution of these high intensity lesions, since it is believed that the abnormality may not be entirely limited to the white matter only. Eleven patients with proven haptic encephalopathy and three normal persons without any evidence of liver abnormality constituted our current data base. Trans-axial, sagittal, and coronal brain MRI were obtained on a 1.5 Tesla scanner. All processing was carried out on a microcomputer-based image analysis system in an off-line manner. Histograms were decomposed into regular brain tissues and lesions. Gray scale ranges coded as lesion were then brought back to original images to identify distribution of abnormality. Our results indicated the disease process involved pallidus, mesencephalon, and subthalamic regions.

  14. A nested phosphorus and proton coil array for brain magnetic resonance imaging and spectroscopy.

    Science.gov (United States)

    Brown, Ryan; Lakshmanan, Karthik; Madelin, Guillaume; Parasoglou, Prodromos

    2016-01-01

    A dual-nuclei radiofrequency coil array was constructed for phosphorus and proton magnetic resonance imaging and spectroscopy of the human brain at 7T. An eight-channel transceive degenerate birdcage phosphorus module was implemented to provide whole-brain coverage and significant sensitivity improvement over a standard dual-tuned loop coil. A nested eight-channel proton module provided adequate sensitivity for anatomical localization without substantially sacrificing performance on the phosphorus module. The developed array enabled phosphorus spectroscopy, a saturation transfer technique to calculate the global creatine kinase forward reaction rate, and single-metabolite whole-brain imaging with 1.4cm nominal isotropic resolution in 15min (2.3cm actual resolution), while additionally enabling 1mm isotropic proton imaging. This study demonstrates that a multi-channel array can be utilized for phosphorus and proton applications with improved coverage and/or sensitivity over traditional single-channel coils. The efficient multi-channel coil array, time-efficient pulse sequences, and the enhanced signal strength available at ultra-high fields can be combined to allow volumetric assessment of the brain and could provide new insights into the underlying energy metabolism impairment in several neurodegenerative conditions, such as Alzheimer's and Parkinson's diseases, as well as mental disorders such as schizophrenia.

  15. Carbon-13 and proton nuclear magnetic resonance analysis of shale-derived refinery products and jet fuels and of experimental referee broadened-specification jet fuels

    Science.gov (United States)

    Dalling, D. K.; Bailey, B. K.; Pugmire, R. J.

    1984-01-01

    A proton and carbon-13 nuclear magnetic resonance (NMR) study was conducted of Ashland shale oil refinery products, experimental referee broadened-specification jet fuels, and of related isoprenoid model compounds. Supercritical fluid chromatography techniques using carbon dioxide were developed on a preparative scale, so that samples could be quantitatively separated into saturates and aromatic fractions for study by NMR. An optimized average parameter treatment was developed, and the NMR results were analyzed in terms of the resulting average parameters; formulation of model mixtures was demonstrated. Application of novel spectroscopic techniques to fuel samples was investigated.

  16. Low energy proton bidirectional anisotropies and their relation to transient interplanetary magnetic structures: ISEE-3 observations

    Science.gov (United States)

    Marsden, R. G.; Sanderson, T. R.; Wenzel, K. P.; Smith, E. J.

    1985-01-01

    It is known that the interplanetary medium in the period approaching solar maximum is characterized by an enhancement in the occurrence of transient solar wind streams and shocks and that such systems are often associated with looplike magnetic structures or clouds. There is observational evidence that bidirectional, field aligned flows of low energy particles could be a signature of such looplike structures, although detailed models for the magnetic field configuration and injection mechanisms do not exist at the current time. Preliminary results of a survey of low energy proton bidirectional anisotropies measured on ISEE-3 in the interplanetary medium between August 1978 and May 1982, together with magnetic field data from the same spacecraft are presented.

  17. Studies related to primitive chemistry. A proton and nitrogen-14 nuclear magnetic resonance amino acid and nucleic acid constituents and a and their possible relation to prebiotic

    Science.gov (United States)

    Manatt, S. L.; Cohen, E. A.; Shiller, A. M.; Chan, S. I.

    1973-01-01

    Preliminary proton nuclear magnetic resonance (NMR) studies were made to determine the applicability of this technique for the study of interactions between monomeric and polymeric amino acids with monomeric nucleic acid bases and nucleotides. Proton NMR results for aqueous solutions (D2O) demonstrated interactions between the bases cytosine and adenine and acidic and aromatic amino acids. Solutions of 5'-AMP admixed with amino acids exhibited more complex behavior but stacking between aromatic rings and destacking at high amino acids concentration was evident. The multisite nature of 5'-AMP was pointed out. Chemical shift changes for adenine and 5'-AMP with three water soluble polypeptides demonstrated that significant interactions exist. It was found that the linewidth-pH profile of each amino acid is unique. It is concluded that NMR techniques can give significant and quantitative data on the association of amino acid and nucleic acid constituents.

  18. Pathological Assessment of Brain White Matter in Relapsing-Remitting MS Patients using Quantitative Magnetization Transfer Imaging

    Directory of Open Access Journals (Sweden)

    Khodarahm Pahlevan

    2011-09-01

    Full Text Available Introduction: Multiple sclerosis (MS is characterized by lesions in the white matter (WM of the central nervous system. Magnetic resonance imaging is the most specific and sensitive method for diagnosis of multiple sclerosis. However, the ability of conventional MRI to show histopathologic heterogeneity of MS lesions is insufficient. Quantitative magnetization transfer imaging (qMTI is a relatively new method to investigate pathologic processes of the brain tissue occurring in MS patients. Material and Methods: Voxel-based analyses allow regional comparisons between groups to be made for the whole brain in a single analysis. This is done by coregistering data from all individual subjects to a reference brain, generally referred to as the "standard space", and then comparing them on a voxel-by-voxel basis. This study aimed to analyze whole-brain quantitative T1 maps, not to find global changes or changes in selected regions, but specifically to investigate the spatial distribution throughout the brain of T1 increases in MS WM with respect to control WM. In this study, 11 healthy controls, 10 relapsing-remitting (RR MS patients and 13 CIS patients were studied using MT-MRI imaging. MT parameters, including magnetization transfer ratio (MTR, magnetization transfer rate between free protons and restricted macromolecular protons, Ksat and longitudinal relaxation times (with and without MT saturation pulse, T1sat and T1free values were evaluated. Results: The results showed that, at a group level, there is widespread involvement of WM throughout the brain in CIS MS and especially in RRMS, where a significant T1 increase was found in 15.58% of WM voxels (normals < RR. Discussion and Conclusion: This study demonstrates that WM in large parts of the brain is susceptible to disease processes in RR and CIS MS

  19. Influence of the interface on the magnetic properties of NiZn ferrite thin films treated by proton irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, X.D. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Guo, D.W. [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Zhang, C.H., E-mail: c.h.zhang@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Fan, X.L.; Chai, G.Z. [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Xue, D.S., E-mail: xueds@lzu.edu.cn [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China)

    2015-09-01

    In order to systematically investigate the influence of the interface on the magnetic properties, polycrystalline NiZn ferrite thin films were irradiated with 60 keV proton in the dose range from 5 × 10{sup 12} to 5 × 10{sup 16} ions/cm{sup 2}. A non-destructive approach by proton irradiation was found to finely adjust the magnetic properties of polycrystalline NiZn ferrite thin films such as coercivity, perpendicular magnetic anisotropy as well as the effective g value. The coercivity is about 725 Oe for high proton dose ferrite, which is twice larger than the unirradiated one. The ferromagnetic resonance measurements indicated that perpendicular magnetic anisotropy and the effective g value increase with the irradiation dose. Our finding indicates that all modifications of these magnetic properties were associated with the change of interface due to the diffusion and the stress induced by proton irradiation. The change of the effective g value is a result of lattice expansion and the decrease of the magnetic dipole interaction between the columnar grains. This work provides a feasible way to tailor the magnetic properties of thin films by ion irradiation and promotes investigations for the stability of magnetic thin film devices in space or unclear radiation environments.

  20. Characterization of SPEEK/Y2O3 proton exchange membrane treated with high magnetic field

    Institute of Scientific and Technical Information of China (English)

    TONG Juying; GUO Qiang; TAN Xiaolin; LI Xia; LI Dan; DONG Yunfeng

    2011-01-01

    The membranes of sulfonated poly(etheretherketone) of 48.3% sulfonation degree doped with Y2O3 were prepared, and then treated with parallel high magnetic field of 6 and 12 T at 120 ℃ for 4 h, respectively. The small-angle X-ray scattering revealed that the structure of the composite membranes would be changed by high magnetic field treatment. The cross-section morphology of the composite membranes by a scanning electron microscope showed that the Y2O3 could be dispersed evenly in the composite membranes which were relatively smooth and compact but formed small conglomeration with increasing Y2O3 content and treating high magnetic field. The water uptake of membranes would be reduced with Y2O3 content increasing, but not be modified by the treatment of high magnetic field. The proton conductivity of membranes would be increased with temperature rising from 20 to 60 ℃, and improved under high magnetic field, which could all exceed 10-2 S/cm at 75% relative humidity, but decrease with doping content of Y2O3 from 2 wt.% to 8 wt.%. The methanol permeability of the composite membranes would be decreased with Y2O3 content increasing and slightly reduced after high magnetic field treatment.

  1. A superconducting magnet mandrel with minimum symmetry laminations for proton therapy

    Science.gov (United States)

    Caspi, S.; Arbelaez, D.; Brouwer, L.; Dietderich, D. R.; Felice, H.; Hafalia, R.; Prestemon, S.; Robin, D.; Sun, C.; Wan, W.

    2013-08-01

    The size and weight of ion-beam cancer therapy gantries are frequently determined by a large aperture, curved, ninety degree, dipole magnet. The higher fields achievable with superconducting technology promise to greatly reduce the size and weight of this magnet and therefore also the gantry as a whole. This paper reports advances in the design of winding mandrels for curved, canted cosine-theta (CCT) magnets in the context of a preliminary magnet design for a proton gantry. The winding mandrel is integral to the CCT design and significantly affects the construction cost, stress management, winding feasibility, eddy current power losses, and field quality of the magnet. A laminated mandrel design using a minimum symmetry in the winding path is introduced and its feasibility demonstrated by a rapid prototype model. Piecewise construction of the mandrel using this laminated approach allows for increased manufacturing techniques and material choices. Sectioning the mandrel also reduces eddy currents produced during field changes accommodating the scan of beam energies during treatment. This symmetry concept can also greatly reduce the computational resources needed for 3D finite element calculations. It is shown that the small region of symmetry forming the laminations combined with periodic boundary conditions can model the entire magnet geometry disregarding the ends.

  2. Quantitative perfusion imaging in magnetic resonance imaging; Quantitative Perfusionsbildgebung in der Magnetresonanztomographie

    Energy Technology Data Exchange (ETDEWEB)

    Zoellner, F.G.; Gaa, T.; Zimmer, F. [Universitaet Heidelberg, Computerunterstuetzte Klinische Medizin, Medizinische Fakultaet Mannheim, Mannheim (Germany); Ong, M.M.; Riffel, P.; Hausmann, D.; Schoenberg, S.O.; Weis, M. [Universitaet Heidelberg, Institut fuer Klinische Radiologie und Nuklearmedizin, Universitaetsmedizin Mannheim, Medizinische Fakultaet Mannheim, Mannheim (Germany)

    2016-02-15

    Magnetic resonance imaging (MRI) is recognized for its superior tissue contrast while being non-invasive and free of ionizing radiation. Due to the development of new scanner hardware and fast imaging techniques during the last decades, access to tissue and organ functions became possible. One of these functional imaging techniques is perfusion imaging with which tissue perfusion and capillary permeability can be determined from dynamic imaging data. Perfusion imaging by MRI can be performed by two approaches, arterial spin labeling (ASL) and dynamic contrast-enhanced (DCE) MRI. While the first method uses magnetically labelled water protons in arterial blood as an endogenous tracer, the latter involves the injection of a contrast agent, usually gadolinium (Gd), as a tracer for calculating hemodynamic parameters. Studies have demonstrated the potential of perfusion MRI for diagnostics and also for therapy monitoring. The utilization and application of perfusion MRI are still restricted to specialized centers, such as university hospitals. A broad application of the technique has not yet been implemented. The MRI perfusion technique is a valuable tool that might come broadly available after implementation of standards on European and international levels. Such efforts are being promoted by the respective professional bodies. (orig.) [German] Die Magnetresonanztomographie (MRT) zeichnet sich durch einen ueberlegenen Gewebekontrast aus, waehrend sie nichtinvasiv und frei von ionisierender Strahlung ist. Sie bietet Zugang zu Gewebe- und Organfunktion. Eine dieser funktionellen bildgebenden Verfahren ist die Perfusionsbildgebung. Mit dieser Technik koennen u. a. Gewebeperfusion und Kapillarpermeabilitaet aus dynamischen Bilddaten bestimmt werden. Perfusionsbildgebung mithilfe der MRT kann durch 2 Ansaetze, naemlich ''arterial spin labeling'' (ASL) und dynamische kontrastverstaerkte (DCE-)MRT durchgefuehrt werden. Waehrend die erste Methode magnetisch

  3. Strange magnetic form factor of the proton at $Q^2 = 0.23$ GeV$^2$

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ping; Leinweber, Derek; Thomas, Anthony; Young, Ross

    2009-06-01

    We determine the $u$ and $d$ quark contributions to the proton magnetic form factor at finite momentum transfer by applying chiral corrections to quenched lattice data. Heavy baryon chiral perturbation theory is applied at next to leading order in the quenched, and full QCD cases for the valence sector using finite range regularization. Under the assumption of charge symmetry these values can be combined with the experimental values of the proton and neutron magnetic form factors to deduce a relatively accurate value for the strange magnetic form factor at $Q^2=0.23$ GeV$^2$, namely $G_M^s=-0.034 \\pm 0.021$ $\\mu_N$.

  4. Metabolite profile of cerebrospinal fluid in patients with spina bifida: a proton magnetic resonance spectroscopy study.

    Science.gov (United States)

    Pal, Kamalesh; Sharma, Uma; Gupta, D K; Pratap, Akshay; Jagannathan, N R

    2005-02-01

    The present study was carried out to assess the metabolic differences between cerebrospinal fluid samples of patients with spina bifida and age-matched control individuals. To study the metabolite profile of cerebrospinal fluid of patients with spina bifida using proton magnetic resonance spectroscopy, compare the levels of metabolites with controls, establish correlation of underlying neuronal dysfunction with metabolic changes in patients with spina bifida, and evaluate the potential use of this technique as an additional tool for diagnostic assessment. Combination of embryopathy, stretching, ischemia, compression, and trauma is responsible for cord dysfunction in spina bifida. Changes in neuronal metabolism leads to changes in the local milieu of cerebrospinal fluid in the cord. Change in metabolite profile of cerebrospinal fluid in spina bifida in terms of increase in products of anaerobic metabolism, nerve membrane integrity, and nerve ischemia has not yet been studied. Cerebrospinal fluid obtained from patients and control individuals were characterized using various one- and two-dimensional proton magnetic resonance spectroscopy techniques. Concentration of various metabolites was calculated using the area under the nuclear magnetic resonance peak. Statistically significantly higher levels of lactate, choline, glycerophosphocholine, acetate, and alanine in the cerebrospinal fluid of patients with spina bifida was observed compared with control individuals. Significantly higher levels of metabolites were observed in patients with spina bifida, representing a state of nerve ischemia, anaerobic metabolism, and disruption of neuronal membrane.

  5. The effect of polymer coatings on proton transverse relaxivities of aqueous suspensions of magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Carroll, Matthew R J; House, Michael J; Woodward, Robert C; St Pierre, Timothy G [School of Physics, University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009 (Australia); Huffstetler, Phillip P; Miles, William C; Goff, Jonathon D; Davis, Richey M; Riffle, Judy S, E-mail: stpierre@physics.uwa.edu.au [Macromolecules and Interfaces Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States)

    2011-08-12

    Iron oxide magnetic nanoparticles are good candidates for magnetic resonance imaging (MRI) contrast agents due to their high magnetic susceptibilities. Here we investigate 19 polyether-coated magnetite nanoparticle systems comprising three series. All systems were synthesized from the same batch of magnetite nanoparticles. A different polyether was used for each series. Each series comprised systems with systematically varied polyether loadings per particle. A highly significant (p < 0.0001) linear correlation (r = 0.956) was found between the proton relaxivity and the intensity-weighted average diameter measured by dynamic light scattering in the 19 particle systems studied. The intensity-weighted average diameter measured by dynamic light scattering is sensitive to small number fractions of larger particles/aggregates. We conclude that the primary effect leading to differences in proton relaxivity between systems arises from the small degree of aggregation within the samples, which appears to be determined by the nature of the polymer and, for one system, the degree of polymer loading of the particles. For the polyether coatings used in this study, any changes in relaxivity from differences in water exclusion or diffusion rates caused by the polymer are minor in comparison with the changes in relaxivity resulting from variations in the degree of aggregation.

  6. Temperature dependence of proton NMR relaxation times at earth's magnetic field

    Science.gov (United States)

    Niedbalski, Peter; Kiswandhi, Andhika; Parish, Christopher; Ferguson, Sarah; Cervantes, Eduardo; Oomen, Anisha; Krishnan, Anagha; Goyal, Aayush; Lumata, Lloyd

    The theoretical description of relaxation processes for protons, well established and experimentally verified at conventional nuclear magnetic resonance (NMR) fields, has remained untested at low fields despite significant advances in low field NMR technology. In this study, proton spin-lattice relaxation (T1) times in pure water and water doped with varying concentrations of the paramagnetic agent copper chloride have been measured from 6 to 92oC at earth's magnetic field (1700 Hz). Results show a linear increase of T1 with temperature for each of the samples studied. Increasing the concentration of the copper chloride greatly reduced T1 and reduced dependence on temperature. The consistency of the results with theory is an important confirmation of past results, while the ability of an ultra-low field NMR system to do contrast-enhanced magnetic resonance imaging (MRI) is promising for future applicability to low-cost medical imaging and chemical identification. This work is supported by US Dept of Defense Award No. W81XWH-14-1-0048 and the Robert A. Welch Foundation Grant No. AT-1877.

  7. Metabolic imaging of human kidney triglyceride content: reproducibility of proton magnetic resonance spectroscopy.

    Directory of Open Access Journals (Sweden)

    Sebastiaan Hammer

    Full Text Available OBJECTIVE: To assess the feasibility of renal proton magnetic resonance spectroscopy for quantification of triglyceride content and to compare spectral quality and reproducibility without and with respiratory motion compensation in vivo. MATERIALS AND METHODS: The Institutional Review Board of our institution approved the study protocol, and written informed consent was obtained. After technical optimization, a total of 20 healthy volunteers underwent renal proton magnetic resonance spectroscopy of the renal cortex both without and with respiratory motion compensation and volume tracking. After the first session the subjects were repositioned and the protocol was repeated to assess reproducibility. Spectral quality (linewidth of the water signal and triglyceride content were quantified. Bland-Altman analyses and a test by Pitman were performed. RESULTS: Linewidth changed from 11.5±0.4 Hz to 10.7±0.4 Hz (all data pooled, p<0.05, without and with respiratory motion compensation respectively. Mean % triglyceride content in the first and second session without respiratory motion compensation were respectively 0.58±0.12% and 0.51±0.14% (P = NS. Mean % triglyceride content in the first and second session with respiratory motion compensation were respectively 0.44±0.10% and 0.43±0.10% (P = NS between sessions and P = NS compared to measurements with respiratory motion compensation. Bland-Altman analyses showed narrower limits of agreement and a significant difference in the correlated variances (correlation of -0.59, P<0.05. CONCLUSION: Metabolic imaging of the human kidney using renal proton magnetic resonance spectroscopy is a feasible tool to assess cortical triglyceride content in humans in vivo and the use of respiratory motion compensation significantly improves spectral quality and reproducibility. Therefore, respiratory motion compensation seems a necessity for metabolic imaging of renal triglyceride content in vivo.

  8. Characterization of the ELIMED Permanent Magnets Quadrupole system prototype with laser-driven proton beams

    Science.gov (United States)

    Schillaci, F.; Pommarel, L.; Romano, F.; Cuttone, G.; Costa, M.; Giove, D.; Maggiore, M.; Russo, A. D.; Scuderi, V.; Malka, V.; Vauzour, B.; Flacco, A.; Cirrone, G. A. P.

    2016-07-01

    Laser-based accelerators are gaining interest in recent years as an alternative to conventional machines [1]. In the actual ion acceleration scheme, energy and angular spread of the laser-driven beams are the main limiting factors for beam applications and different solutions for dedicated beam-transport lines have been proposed [2,3]. In this context a system of Permanent Magnet Quadrupoles (PMQs) has been realized [2] by INFN-LNS (Laboratori Nazionali del Sud of the Instituto Nazionale di Fisica Nucleare) researchers, in collaboration with SIGMAPHI company in France, to be used as a collection and pre-selection system for laser driven proton beams. This system is meant to be a prototype to a more performing one [3] to be installed at ELI-Beamlines for the collection of ions. The final system is designed for protons and carbons up to 60 MeV/u. In order to validate the design and the performances of this large bore, compact, high gradient magnetic system prototype an experimental campaign have been carried out, in collaboration with the group of the SAPHIR experimental facility at LOA (Laboratoire d'Optique Appliquée) in Paris using a 200 TW Ti:Sapphire laser system. During this campaign a deep study of the quadrupole system optics has been performed, comparing the results with the simulation codes used to determine the setup of the PMQ system and to track protons with realistic TNSA-like divergence and spectrum. Experimental and simulation results are good agreement, demonstrating the possibility to have a good control on the magnet optics. The procedure used during the experimental campaign and the most relevant results are reported here.

  9. The neurochemical basis of human cortical auditory processing: combining proton magnetic resonance spectroscopy and magnetoencephalography

    Directory of Open Access Journals (Sweden)

    Tollkötter Melanie

    2006-08-01

    Full Text Available Abstract Background A combination of magnetoencephalography and proton magnetic resonance spectroscopy was used to correlate the electrophysiology of rapid auditory processing and the neurochemistry of the auditory cortex in 15 healthy adults. To assess rapid auditory processing in the left auditory cortex, the amplitude and decrement of the N1m peak, the major component of the late auditory evoked response, were measured during rapidly successive presentation of acoustic stimuli. We tested the hypothesis that: (i the amplitude of the N1m response and (ii its decrement during rapid stimulation are associated with the cortical neurochemistry as determined by proton magnetic resonance spectroscopy. Results Our results demonstrated a significant association between the concentrations of N-acetylaspartate, a marker of neuronal integrity, and the amplitudes of individual N1m responses. In addition, the concentrations of choline-containing compounds, representing the functional integrity of membranes, were significantly associated with N1m amplitudes. No significant association was found between the concentrations of the glutamate/glutamine pool and the amplitudes of the first N1m. No significant associations were seen between the decrement of the N1m (the relative amplitude of the second N1m peak and the concentrations of N-acetylaspartate, choline-containing compounds, or the glutamate/glutamine pool. However, there was a trend for higher glutamate/glutamine concentrations in individuals with higher relative N1m amplitude. Conclusion These results suggest that neuronal and membrane functions are important for rapid auditory processing. This investigation provides a first link between the electrophysiology, as recorded by magnetoencephalography, and the neurochemistry, as assessed by proton magnetic resonance spectroscopy, of the auditory cortex.

  10. Isotropic proton-detected local-field nuclear magnetic resonancein solids

    Energy Technology Data Exchange (ETDEWEB)

    Havlin, Robert H.; Walls, Jamie D.; Pines, Alexander

    2004-08-04

    A new nuclear magnetic resonance (NMR) method is presented which produces linear, isotropic proton-detected local-field spectra for InS spin systems in powdered samples. The method, HETeronuclear Isotropic Evolution (HETIE), refocuses the anisotropic portion of the heteronuclear dipolar coupling frequencies by evolving the system under a series of specially designed Hamiltonians and evolution pathways. The theory behind HETIE is represented along with experimental studies conducted on a powdered sample of ferrocene, demonstrating the methodology outlined in this paper. Applications of HETIE for structural determination in solid-state NMR are discussed.

  11. Magnetic Moment and Spin of the Extremely Proton-Rich Nucleus {sup 23}Al

    Energy Technology Data Exchange (ETDEWEB)

    Matsuta, K., E-mail: matsuta@vg.phys.sci.osaka-u.ac.jp; Nakashima, Y.; Nagatomo, T.; Mihara, M.; Kumashiro, S.; Fujiwara, H.; Ogura, M.; Fukuda, M.; Minamisono, T. [Osaka University, Department of Physics (Japan); Sumikama, T. [RIKEN (Japan); Ozawa, A. [University of Tsukuba, Institute of Physics (Japan); Yamada, K. [Rikkyo University, College of Science (Japan); Momota, S.; Nojiri, Y. [Tosayamada, Kochi University of Technology (Japan); Ota, M.; Ohtsubo, T.; Izumikawa, T. [Niigata University, Department of Physics (Japan); Yoshida, K. [RIKEN (Japan); Minamisono, K. [TRIUMF (Canada); Suzuki, T. [Saitama University, Department of Physics (Japan)

    2004-12-15

    The g-factor of the exteremely proton-rich nucleus {sup 23}Al(T{sub 1/2} 0.47 s) has been measured for the first time, applying {beta}-NMR technique on this nucleus implanted in Si. The obtained vertical bar g vertical bar (1.58 {+-} 0.2) suggests that the spin of the ground state of {sup 23}Al is 5 / 2. The magnetic moment is determined as vertical bar {mu} vertical bar (3.95 {+-} 0.55) {mu}{sub N}.

  12. Search For Magnetic Monopoles Possibly Produced By Proton-antiproton Collisions At The Tevatron Collider

    CERN Document Server

    Luo, W

    2002-01-01

    Magnetic monopoles can be used to explain the quantization of electric charge, and are predicted by gauge field theory. If monopoles exist, they could have been produced by the proton-antiproton collisions at the Tevatron collider—the highest energy accelerator existing in the world, and trapped in the CDF and DØ detectors. We took Al, Be, and Pb samples from the Tevatron and used the induction technique with SQUIDs (Superconducting Quantum Interference Devices) to detect monopoles in the samples. We did not find monopoles, but we have set new limits for the monopole mass and the relavant cross section based on a Drell-Yan model and Monte Carlo calculation.

  13. Quantitative magnetic force microscopy on perpendicularly magnetised samples

    NARCIS (Netherlands)

    Hug, Hans J.; Stiefel, B.; van Schendel, P.J.A.; Schendel, P.J.A.; Moser, A.; Hofer, R.; Martin, S.; Guntherodt, H.J.; Porthun, S.; Porthun, Steffen; Abelmann, Leon; Lodder, J.C.; Bochi, Gabriel; O'handley, R.C.

    1998-01-01

    We present a transfer-function approach to calculate the force on a magnetic force microscope tip and the stray field due to a perpendicularly magnetized medium having an arbitrary magnetization pattern. Under certain conditions, it is possible to calculate the magnetization pattern from the

  14. Monitoring temozolomide treatment of low-grade glioma with proton magnetic resonance spectroscopy

    DEFF Research Database (Denmark)

    Murphy, P. S.; Viviers, L; Abson, C;

    2004-01-01

    Assessment of low-grade glioma treatment response remains as much of a challenge as the treatment itself. Proton magnetic resonance spectroscopy ((1)H-MRS) and imaging were incorporated into a study of patients receiving temozolomide therapy for low-grade glioma in order to evaluate and monitor...... tumour metabolite and volume changes during treatment. Patients (n=12) received oral temozolomide (200 mg m(-2) day(-1)) over 5 days on a 28-day cycle for 12 cycles. Response assessment included baseline and three-monthly magnetic resonance imaging studies (pretreatment, 3, 6, 9 and 12 months) assessing...... months, a significant reduction in the mean choline signal was observed compared with the pretreatment (P=0.035) and 3-month scan (P=0.021). The reduction in the tumour choline/water signal paralleled tumour volume change and may reflect the therapeutic effect of temozolomide...

  15. The emergence of proton nuclear magnetic resonance metabolomics in the cardiovascular arena as viewed from a clinical perspective.

    Science.gov (United States)

    Rankin, Naomi J; Preiss, David; Welsh, Paul; Burgess, Karl E V; Nelson, Scott M; Lawlor, Debbie A; Sattar, Naveed

    2014-11-01

    The ability to phenotype metabolic profiles in serum has increased substantially in recent years with the advent of metabolomics. Metabolomics is the study of the metabolome, defined as those molecules with an atomic mass less than 1.5 kDa. There are two main metabolomics methods: mass spectrometry (MS) and proton nuclear magnetic resonance ((1)H NMR) spectroscopy, each with its respective benefits and limitations. MS has greater sensitivity and so can detect many more metabolites. However, its cost (especially when heavy labelled internal standards are required for absolute quantitation) and quality control is sub-optimal for large cohorts. (1)H NMR is less sensitive but sample preparation is generally faster and analysis times shorter, resulting in markedly lower analysis costs. (1)H NMR is robust, reproducible and can provide absolute quantitation of many metabolites. Of particular relevance to cardio-metabolic disease is the ability of (1)H NMR to provide detailed quantitative data on amino acids, fatty acids and other metabolites as well as lipoprotein subparticle concentrations and size. Early epidemiological studies suggest promise, however, this is an emerging field and more data is required before we can determine the clinical utility of these measures to improve disease prediction and treatment. This review describes the theoretical basis of (1)H NMR; compares MS and (1)H NMR and provides a tabular overview of recent (1)H NMR-based research findings in the atherosclerosis field, describing the design and scope of studies conducted to date. (1)H NMR metabolomics-CVD related research is emerging, however further large, robustly conducted prospective, genetic and intervention studies are needed to advance research on CVD risk prediction and to identify causal pathways amenable to intervention. Copyright © 2014 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  16. Non-destructive Ripeness Sensing by Using Proton NMR [Nuclear Magnetic Resonance

    Science.gov (United States)

    Cho, Seong In; Krutz, G. W.; Stroshine, R. L.; Bellon, V.

    1990-01-01

    More than 80 kinds of fruits and vegetables are available in the United States. But only about 6 of them have their quality standards (Dull, 1986). In the 1990 Fresh Trends survey (Zind, 1990), consumers were asked to rate 16 characteristics important to their decision to purchase fresh produce. The four top ranking factors were ripeness/freshness, taste/flavor, appearance/condition and nutritional value. Of these surveyed, 96% rated ripeness/freshness as extremely important or very important. Therefore, the development of reliable grading or sorting techniques for fresh commodities is essential. Determination of fruit quality often involves cutting and tasting. Non-destructive quality control in fruit and vegetables is a goal of growers and distributors, as well as the food processing industry. Many nondestructive techniques have been evaluated including soft x-ray, optical transmission, near infrared radiation, and machine vision. However, there are few reports of successful non-destructive measurement of sugar content directly in fruit. Higher quality fruit could be harvested and available to consumers if a nondestructive sensor that detects ripeness level directly by measuring sugar content were available. Using proton Nuclear Magnetic Resonance (NMR) principle is the possibility. A nondestructive ripeness (or sweetness) sensor for fruit quality control can be developed with the proton NMR principle (Cho, 1989). Several feasibility studies were necessary for the ripeness sensor development. Main objectives in this paper was to investigate the feasibilities (1) to detect ripeness (or sweetness level) of raw fruit tissue with an high resolution proton NMR spectroscopy (200 MHz) and (2) to measure sugar content of intact fruit with a low resolution proton NMR spectroscopy (10 MHz).

  17. Quantitative investigation of physical factors contributing to gold nanoparticle-mediated proton dose enhancement

    Science.gov (United States)

    Cho, Jongmin; Gonzalez-Lepera, Carlos; Manohar, Nivedh; Kerr, Matthew; Krishnan, Sunil; Cho, Sang Hyun

    2016-03-01

    Some investigators have shown tumor cell killing enhancement in vitro and tumor regression in mice associated with the loading of gold nanoparticles (GNPs) before proton treatments. Several Monte Carlo (MC) investigations have also demonstrated GNP-mediated proton dose enhancement. However, further studies need to be done to quantify the individual physical factors that contribute to the dose enhancement or cell-kill enhancement (or radiosensitization). Thus, the current study investigated the contributions of particle-induced x-ray emission (PIXE), particle-induced gamma-ray emission (PIGE), Auger and secondary electrons, and activation products towards the total dose enhancement. Specifically, GNP-mediated dose enhancement was measured using strips of radiochromic film that were inserted into vials of cylindrical GNPs, i.e. gold nanorods (GNRs), dispersed in a saline solution (0.3 mg of GNRs/g or 0.03% of GNRs by weight), as well as vials containing water only, before proton irradiation. MC simulations were also performed with the tool for particle simulation code using the film measurement setup. Additionally, a high-purity germanium detector system was used to measure the photon spectrum originating from activation products created from the interaction of protons and spherical GNPs present in a saline solution (20 mg of GNPs/g or 2% of GNPs by weight). The dose enhancement due to PIXE/PIGE recorded on the films in the GNR-loaded saline solution was less than the experimental uncertainty of the film dosimetry (PIGE, and activation products contribute minimally to GNP/GNR-mediated proton dose enhancement, whereas Auger/secondary electrons contribute significantly but only at short distances (<100 nm) from GNPs/GNRs.

  18. Power Supply for Magnet of Compact Proton and/or Heavy Ion Synchrotron for Radiotherapy

    CERN Document Server

    Yamanaka, Shinji; Endo, Kuninori; Fang, Zhigao

    2005-01-01

    A resonant type pulse power supply, for an application to a compact proton and/or heavy ion synchrotron with a several Hz repetition rate, is attractive from the view point of attaining an average beam current that is enough for the radiation therapy. Maximum ampere-turn of the dipole magnet is as large as 200 kAT to make the bending radius as small as possible. Pulse current is generated by discharging the stored energy in a capacitor bank through a pulse transformer. Moreover, the auxiliary power supply for the dipole magnets which adds the flat magnetic field (10-20μs) for the multi-turn beam-injection is being developed. The power supply for the quadrupole magnets is the high switching frequency (20 kHz × 5) switching-mode Power Supply for the adjusting tune and the tracking between the quadrupole and the dipole fields.Detailed analyses on these pulse power supplies will be presented.

  19. Proton magnetic resonance spectroscopy and perfusion magnetic resonance imaging in the evaluation of musculoskeletal tumors; Espectroscopia de protons e perfusao por ressonancia magnetica na avaliacao dos tumores do sistema musculoesqueletico

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Flavia Martins; Setti, Marcela [Clinica de Diagnostico Por Imagem (CDPI), Rio de Janeiro, RJ (Brazil)], e-mail: flavia26rio@hotmail.com; Vianna, Evandro Miguelote; Domingues, Romulo Cortes [Clinica de Diagnostico Por Imagem (CDPI), Rio de Janeiro, RJ (Brazil); Multi-Imagem, Rio de Janeiro, RJ (Brazil); Meohas, Walter; Rezende, Jose Francisco [Instituto Nacional de Cancer (INCA), Rio de Janeiro, RJ (Brazil); Gasparetto, Emerson Leandro [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Clinica de Diagnostico Por Imagem (CDPI), Rio de Janeiro, RJ (Brazil)

    2009-07-15

    Objective: To assess the role of proton magnetic resonance spectroscopy and dynamic contrast-enhanced magnetic resonance imaging in the differentiation between malignant and benign musculoskeletal tumors. Materials And Methods: Fifty-five patients with musculoskeletal tumors (27 malignant and 28 benign) were studied. The examinations were performed in a 1.5 T magnetic resonance scanner with standard protocol, and single voxel proton magnetic resonance spectroscopy with 135 msec echo time. The dynamic contrast study was performed using T1-weighted gradient-echo sequence after intravenous gadolinium injection. Time signal intensity curves and slope values were calculated. The statistical analysis was performed with the Levene's test, followed by a Student's t-test, besides the Pearson's chi-squared and Fischer's exact tests. Results: Proton magnetic resonance spectroscopy sensitivity, specificity and accuracy were, respectively, 87.5%, 92.3% and 90.9% (p < 0.0001). Statistically significant difference was observed in the slope (%/min) between benign (mean, 27.5%/min) and malignant (mean, 110.9%/min) lesions (p < 0.0001). Conclusion: The time-intensity curve and slope values using dynamic-enhanced perfusion magnetic resonance imaging in association with the presence of choline peak demonstrated by single voxel magnetic resonance spectroscopy study are useful in the differentiation between malignant and benign musculoskeletal tumors. (author)

  20. WE-D-BRF-05: Quantitative Dual-Energy CT Imaging for Proton Stopping Power Computation

    Energy Technology Data Exchange (ETDEWEB)

    Han, D; Williamson, J [Virginia Commonwealth University, Richmond, VA (United States); Siebers, J [University of Virginia Health System, Charlottesville, VA (United States)

    2014-06-15

    Purpose: To extend the two-parameter separable basis-vector model (BVM) to estimation of proton stopping power from dual-energy CT (DECT) imaging. Methods: BVM assumes that the photon cross sections of any unknown material can be represented as a linear combination of the corresponding quantities for two bracketing basis materials. We show that both the electron density (ρe) and mean excitation energy (Iex) can be modeled by BVM, enabling stopping power to be estimated from the Bethe-Bloch equation. We have implemented an idealized post-processing dual energy imaging (pDECT) simulation consisting of monogenetic 45 keV and 80 keV scanning beams with polystyrene-water and water-CaCl2 solution basis pairs for soft tissues and bony tissues, respectively. The coefficients of 24 standard ICRU tissue compositions were estimated by pDECT. The corresponding ρe, Iex, and stopping power tables were evaluated via BVM and compared to tabulated ICRU 44 reference values. Results: BVM-based pDECT was found to estimate ρe and Iex with average and maximum errors of 0.5% and 2%, respectively, for the 24 tissues. Proton stopping power values at 175 MeV, show average/maximum errors of 0.8%/1.4%. For adipose, muscle and bone, these errors result range prediction accuracies less than 1%. Conclusion: A new two-parameter separable DECT model (BVM) for estimating proton stopping power was developed. Compared to competing parametric fit DECT models, BVM has the comparable prediction accuracy without necessitating iterative solution of nonlinear equations or a sample-dependent empirical relationship between effective atomic number and Iex. Based on the proton BVM, an efficient iterative statistical DECT reconstruction model is under development.

  1. Motor and premotor cortices in subcortical stroke: proton magnetic resonance spectroscopy measures and arm motor impairment.

    Science.gov (United States)

    Craciunas, Sorin C; Brooks, William M; Nudo, Randolph J; Popescu, Elena A; Choi, In-Young; Lee, Phil; Yeh, Hung-Wen; Savage, Cary R; Cirstea, Carmen M

    2013-06-01

    Although functional imaging and neurophysiological approaches reveal alterations in motor and premotor areas after stroke, insights into neurobiological events underlying these alterations are limited in human studies. We tested whether cerebral metabolites related to neuronal and glial compartments are altered in the hand representation in bilateral motor and premotor areas and correlated with distal and proximal arm motor impairment in hemiparetic persons. In 20 participants at >6 months postonset of a subcortical ischemic stroke and 16 age- and sex-matched healthy controls, the concentrations of N-acetylaspartate and myo-inositol were quantified by proton magnetic resonance spectroscopy. Regions of interest identified by functional magnetic resonance imaging included primary (M1), dorsal premotor (PMd), and supplementary (SMA) motor areas. Relationships between metabolite concentrations and distal (hand) and proximal (shoulder/elbow) motor impairment using Fugl-Meyer Upper Extremity (FMUE) subscores were explored. N-Acetylaspartate was lower in M1 (P = .04) and SMA (P = .004) and myo-inositol was higher in M1 (P = .003) and PMd (P = .03) in the injured (ipsilesional) hemisphere after stroke compared with the left hemisphere in controls. N-Acetylaspartate in ipsilesional M1 was positively correlated with hand FMUE subscores (P = .04). Significant positive correlations were also found between N-acetylaspartate in ipsilesional M1, PMd, and SMA and in contralesional M1 and shoulder/elbow FMUE subscores (P = .02, .01, .02, and .02, respectively). Our preliminary results demonstrated that proton magnetic resonance spectroscopy is a sensitive method to quantify relevant neuronal changes in spared motor cortex after stroke and consequently increase our knowledge of the factors leading from these changes to arm motor impairment.

  2. High sensitivity piezomagnetic force microscopy for quantitative probing of magnetic materials at the nanoscale.

    Science.gov (United States)

    Chen, Qian Nataly; Ma, Feiyue; Xie, Shuhong; Liu, Yuanming; Proksch, Roger; Li, Jiangyu

    2013-07-01

    Accurate scanning probing of magnetic materials at the nanoscale is essential for developing and characterizing magnetic nanostructures, yet quantitative analysis is difficult using the state of the art magnetic force microscopy, and has limited spatial resolution and sensitivity. In this communication, we develop a novel piezomagnetic force microscopy (PmFM) technique, with the imaging principle based on the detection of magnetostrictive response excited by an external magnetic field. In combination with the dual AC resonance tracking (DART) technique, the contact stiffness and energy dissipation of the samples can be simultaneously mapped along with the PmFM phase and amplitude, enabling quantitative probing of magnetic materials and structures at the nanoscale with high sensitivity and spatial resolution. PmFM has been applied to probe magnetic soft discs and cobalt ferrite thin films, demonstrating it as a powerful tool for a wide range of magnetic materials.

  3. Search for magnetic monopoles with the MoEDAL prototype trapping detector in 8 TeV proton-proton collisions at the LHC

    CERN Document Server

    Acharya, B.

    2016-08-10

    The MoEDAL experiment is designed to search for magnetic monopoles and other highly-ionising particles produced in high-energy collisions at the LHC. The largely passive MoEDAL detector, deployed at Interaction Point 8 on the LHC ring, relies on two dedicated direct detection techniques. The first technique is based on stacks of nuclear-track detectors with surface area $\\sim$18 m$^2$, sensitive to particle ionisation exceeding a high threshold. These detectors are analysed offline by optical scanning microscopes. The second technique is based on the trapping of charged particles in an array of roughly 800 kg of aluminium samples. These samples are monitored offline for the presence of trapped magnetic charge at a remote superconducting magnetometer facility. We present here the results of a search for magnetic monopoles using a 160 kg prototype MoEDAL trapping detector exposed to 8 TeV proton-proton collisions at the LHC, for an integrated luminosity of 0.75 fb$^{-1}$. No magnetic charge exceeding $0.5g_{\\rm...

  4. Search for magnetic monopoles with the MoEDAL prototype trapping detector in 8 TeV proton-proton collisions at the LHC

    CERN Document Server

    CERN. Geneva

    2016-01-01

    The MoEDAL experiment is designed to search for magnetic monopoles and other highly-ionising particles produced in high-energy collisions at the LHC. The largely passive MoEDAL detector, deployed at Interaction Point 8 on the LHC ring, relies on two dedicated direct detection techniques. The first technique is based on stacks of nuclear-track detectors with surface area ∼18 m2, sensitive to particle ionisation exceeding a high threshold. These detectors are analysed offline by optical scanning microscopes. The second technique is based on the trapping of charged particles in an array of roughly 800 kg of aluminium samples. These samples are monitored offline for the presence of trapped magnetic charge at a remote superconducting magnetometer facility. We present here the results of a search for magnetic monopoles using a 160 kg prototype MoEDAL trapping detector exposed to 8 TeV proton-proton collisions at the LHC, for an integrated luminosity of 0.75 fb−1. No magnetic charge exceeding 0.5gD (where gD is ...

  5. Search for magnetic monopoles with the MoEDAL prototype trapping detector in 8 TeV proton-proton collisions at the LHC

    CERN Document Server

    Acharya, B.

    2016-01-01

    The MoEDAL experiment is designed to search for magnetic monopoles and other highly-ionising particles produced in high-energy collisions at the LHC. The largely passive MoEDAL detector, deployed at Interaction Point 8 on the LHC ring, relies on two dedicated direct detection techniques. The first technique is based on stacks of nuclear-track detectors with surface area $\\sim$18 m$^2$, sensitive to particle ionisation exceeding a high threshold. These detectors are analysed offline by optical scanning microscopes. The second technique is based on the trapping of charged particles in an array of roughly 800 kg of aluminium samples. These samples are monitored offline for the presence of trapped magnetic charge at a remote superconducting magnetometer facility. We present here the results of a search for magnetic monopoles using a 160 kg prototype MoEDAL trapping detector exposed to 8 TeV proton-proton collisions at the LHC, for an integrated luminosity of 0.75 fb$^{-1}$. No magnetic charge exceeding $0.5g_{\\rm...

  6. Localized proton magnetic resonance spectroscopy of the cerebellum in detoxifying alcoholics.

    Science.gov (United States)

    Seitz, D; Widmann, U; Seeger, U; Nägele, T; Klose, U; Mann, K; Grodd, W

    1999-01-01

    An increased daily alcohol consumption results in neurological symptoms and morphological central nervous system changes, e.g. shrinkage of the frontal lobes and the cerebellar vermis. Brain shrinkage can be due to neuronal loss, gliosis, or alterations of (cell) membrane constitutes/myelin. Neuronal, glial, and metabolic changes can be measured in vivo with proton magnetic resonance spectroscopy. A total of 11 alcoholics and 10 age-matched volunteers were examined by magnetic resonance imaging and localized magnetic resonance spectroscopy at an echo time of 135 and 5 msec. Peak integral values were calculated for N-acetylaspartate (NAA), choline (Cho), myo-inositol (ml), glutamate/glutamine (Glx), and normalized to phosphocreatine/creatine (Cr). Patients had a significant shrinkage of the cerebellar vermis. NAA/Cr and Cho/Cr ratios were reduced in both sequences, but the NAA/Cr reduction was only significant in long echo time, although the Cho/Cr reduction was significant in short echo time. The ml/Cr and Glx/Cr ratios did not show any significant difference between volunteers and patients. The decrease of NAA/Cr in alcohol dependent patients is consistent with neuronal loss. The Cho/Cr decrease and an unchanged ml/Cr may reflect cell membrane modification or myelin alterations in alcohol-dependent patients. These changes lead to brain shrinkage, although hydration effects and gliosis are less likely.

  7. An improved permanent magnet quadrupole design with larger good field region for high intensity proton linacs

    Science.gov (United States)

    Mathew, Jose V.; Rao, S. V. L. S.; Krishnagopal, S.; Singh, P.

    2013-11-01

    The Low Energy High Intensity Proton Accelerator (LEHIPA), being developed at the Bhabha Atomic Research Centre (BARC) will produce a 20 MeV, 30 mA, continuous wave (CW) proton beam. At these low velocities, space-charge forces dominate, and could lead to larger beam sizes and beam halos. Hence in the design of the focusing lattice of the LEHIPA drift tube linac (DTL) using permanent magnet quadrupoles (PMQs), a larger good field region is preferred. Here we study, using the two dimensional (2D) and three dimensional (3D) simulation codes PANDIRA and RADIA, four different types of cylindrical PMQ designs: 16-segment trapezoidal Halbach configuration, bullet-nosed geometry and 8- and 16-segment rectangular geometries. The trapezoidal Halbach geometry is used in a variety of accelerators since it provides very high field gradients in small bores, while the bullet-nosed geometry, which is a combination of the trapezoidal and rectangular designs, is used in some DTLs. This study shows that a larger good field region is possible in the 16-segment rectangular design as compared to the Halbach and bullet-nosed designs, making it more attractive for high-intensity proton linacs. An improvement in good-field region by ˜16% over the Halbach design is obtained in the optimized 16-segment rectangular design, although the field gradient is lower by ˜20%. Tolerance studies show that the rectangular segment PMQ design is substantially less sensitive to the easy axis orientation errors and hence will be a better choice for DTLs.

  8. Using microcontact printing to fabricate microcoils on capillaries for high resolution proton nuclear magnetic resonance on nanoliter volumes

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, J.A.; Jackman, R.J.; Whitesides, G.M. [Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138 (United States); Olson, D.L.; Sweedler, J.V. [Beckman Institute and Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

    1997-05-01

    This letter describes a method for producing conducting microcoils for high resolution proton nuclear magnetic resonance ({sup 1}H-NMR) spectroscopy on nanoliter volumes. This technique uses microcontact printing and electroplating to form coils on microcapillaries. Nuclear magnetic resonance spectra collected using these microcoils, have linewidths less than 1 Hz for model compounds and a limit of detection (signal-to-noise ratio=3) for ethylbenzene of 2.6 nmol in 13 min. {copyright} {ital 1997 American Institute of Physics.}

  9. Radiative corrections to the magnetic moments of the proton and the neutron

    CERN Document Server

    Kaiser, N

    2016-01-01

    We estimate the radiative corrections of order $\\alpha/\\pi$ to the magnetic moments of the proton and the neutron. The photon-loop diagram of the vertex-correction type is evaluated with phenomenological nucleon vector form factors. Infrared-finiteness and gauge-invariance require the inclusion of the wave-function renormalization factor from the self-energy diagram. Using recent empirical form factor parametrizations the corrections amount to $\\delta\\kappa_p= -3.42 \\cdot 10^{-3}$ and $\\delta\\kappa_n= 1.34 \\cdot 10^{-3}$. We study also the effects from photon-loops with internal $\\Delta(1232)$-isobars. For two customary versions of the $\\Delta N\\gamma $-vertex and spin-3/2 propagator, these radiative corrections have values of $\\delta\\kappa_p^{(\\Delta)}= (-0.9,\\, 0.0)\\!\\cdot\\! 10^{-3}$ and $\\delta\\kappa_n^{(\\Delta)} = (1.2,\\,-0.8)\\!\\cdot\\! 10^{-3}$, respectively.

  10. Proton magnetic resonance spectroscopy reflects metabolic decompensation in maple syrup urine disease

    Energy Technology Data Exchange (ETDEWEB)

    Heindel, W. [Dept. of Diagnostic Radiology, Univ. Koeln (Germany); Kugel, H. [Dept. of Diagnostic Radiology, Univ. Koeln (Germany); Wendel, U. [Children`s Hospital, Univ. Duesseldorf (Germany); Roth, B. [Children`s Hospital, Univ. Koeln (Germany); Benz-Bohm, G. [Dept. of Diagnostic Radiology, Univ. Koeln (Germany)

    1995-06-01

    Using localized proton magnetic resonance spectroscopy ({sup 1}H-MRS), accumulation of branchedchain amino acids (BCAA) and their corresponding 2-oxo acids (BCOA) could be non-invasively demonstrated in the brain of a 9-year-old girl suffering from classical maple syrup urine disease. During acute metabolic decompensation, the compounds caused a signal at a chemical shift of 0.9 ppm which was assigned by in vitro experiments. The brain tissue concentration of the sum of BCAA and BCOA could be estimated as 0.9 mmol/l. Localized {sup 1}H-MRS of the brain appears to be suitable for examining patients suffering from maple syrup urine disease in different metabolic states. (orig.)

  11. Low-temperature TCT characterization of heavily proton irradiated p-type magnetic Czochralski silicon detectors

    CERN Document Server

    Härkönen, J; Luukka, P; Kassamakov, I; Autioniemi, M; Tuominen, E; Sane, P; Pusa, P; Räisänen, J; Eremin, V; Verbitskaya, E; Li, Z

    2007-01-01

    n+/p−/p+ pad detectors processed at the Microelectronics Center of Helsinki University of Technology on boron-doped p-type high-resistivity magnetic Czochralski (MCz-Si) silicon substrates have been investigated by the transient current technique (TCT) measurements between 100 and 240 K. The detectors were irradiated by 9 MeV protons at the Accelerator Laboratory of University of Helsinki up to 1 MeV neutron equivalent fluence of 2×1015 n/cm2. In some of the detectors the thermal donors (TD) were introduced by intentional heat treatment at 430 °C. Hole trapping time constants and full depletion voltage values were extracted from the TCT data. We observed that hole trapping times in the order of 10 ns were found in heavily (above 1×1015 neq/cm2) irradiated samples. These detectors could be fully depleted below 500 V in the temperature range of 140–180 K.

  12. Design and performance analysis of a compact magnetic proton recoil spectrometer for DT neutrons

    Institute of Scientific and Technical Information of China (English)

    QI Jian-Min; ZHOU Lin; JIANG Shi-Lun

    2011-01-01

    A magnetic proton recoil (MPR) spectrometer is a novel instrument with superior performance, including high energy resolution, high count rate and good signal-to-noise ratio (SNR) for measurements of neutron spectra from inertial confinement fusion (ICF) experiments and high power Tokomaks. In this work, the design of a compact MPR spectrometer (cMPR) was evaluated for deuteron-tritium (DT) neutron spectroscopy. The characteristics of the spectrometer were analyzed using 2-D beam transport simulations, 3-D particle transport calculations and Monte-Carlo simulations. Based on the theoretical results, an instrument design that satisfies special experimental requirements is proposed. The energy resolution and efficiency of the spectrometer are also evaluated. The results indicate that the proposed cMPR spectrometer would achieve a detection efficiency and energy resolution of approximately 10 and 4%, respectively, for DT neutrons.

  13. Viscosity, calorimetric, and proton magnetic resonance studies on coal liquid fractions in solution

    Energy Technology Data Exchange (ETDEWEB)

    Tewari, K.C.; Kan, N.; Susco, D.M.; Li, N.C.

    1979-02-01

    Two coal liquid products derived from the same Kentucky hvAb coal have been separated into toluene-insoluble, asphaltene, and pentane-soluble heavy oil fractions. Viscosity and calorimetric studies are reported of the interaction between heavy oil and asphaltene (A) and its acid/neutral (AA) and base (BA) components in solvent benzene. The increase in viscosity and molar enthalpy of interaction, ..delta..H/sup 0/, in the order BA > A > AA, correlates well with the proton magnetic resonance downfield chemical shift of the OH signal of o-phenylphenol, as a function of added asphaltene (A, AA, BA) concentration in solvent CS/sub 2/. The results suggest that when asphaltene and heavy oil are present together, hydrogen-bonding involving largely phenolic OH, is one of the mechanisms by which asphaltene-heavy oil interactions are achieved and, in part, is responsible for the viscosity increase of coal liquids. 4 figures, 3 tables.

  14. Proton Magnetic Resonance Spectroscopy: Relevance of Glutamate and GABA to Neuropsychology.

    Science.gov (United States)

    Ende, Gabriele

    2015-09-01

    Proton Magnetic Resonance Spectroscopy (MRS) has been widely used to study the healthy and diseased brain in vivo. The availability of whole body MR scanners with a field strength of 3 Tesla and above permit the quantification of many metabolites including the neurotransmitters glutamate (Glu) and γ-aminobutyric acid (GABA). The potential link between neurometabolites identified by MRS and cognition and behavior has been explored in numerous studies both in healthy subjects and in patient populations. Preliminary findings suggest direct or opposite associations between GABA or Glu with impulsivity, anxiety, and dexterity. This chapter is intended to provide an overview of basic principles of MRS and the literature reporting correlations between GABA or Glu and results of neuropsychological assessments.

  15. Proton Magnetic Resonance Spectroscopy and MRI Reveal No Evidence for Brain Mitochondrial Dysfunction in Children with Autism Spectrum Disorder

    Science.gov (United States)

    Corrigan, Neva M.; Shaw, Dennis. W. W.; Richards, Todd L.; Estes, Annette M.; Friedman, Seth D.; Petropoulos, Helen; Artru, Alan A.; Dager, Stephen R.

    2012-01-01

    Brain mitochondrial dysfunction has been proposed as an etiologic factor in autism spectrum disorder (ASD). Proton magnetic resonance spectroscopic imaging ([superscript 1]HMRS) and MRI were used to assess for evidence of brain mitochondrial dysfunction in longitudinal samples of children with ASD or developmental delay (DD), and cross-sectionally…

  16. Proton Magnetic Resonance Spectroscopy and MRI Reveal No Evidence for Brain Mitochondrial Dysfunction in Children with Autism Spectrum Disorder

    Science.gov (United States)

    Corrigan, Neva M.; Shaw, Dennis. W. W.; Richards, Todd L.; Estes, Annette M.; Friedman, Seth D.; Petropoulos, Helen; Artru, Alan A.; Dager, Stephen R.

    2012-01-01

    Brain mitochondrial dysfunction has been proposed as an etiologic factor in autism spectrum disorder (ASD). Proton magnetic resonance spectroscopic imaging ([superscript 1]HMRS) and MRI were used to assess for evidence of brain mitochondrial dysfunction in longitudinal samples of children with ASD or developmental delay (DD), and cross-sectionally…

  17. [Possibilities in the differential diagnosis of brain neoplasms using the long and short time sequences of proton magnetic resonance spectroscopy

    NARCIS (Netherlands)

    Gajewicz, W.; Goraj, B.M.

    2004-01-01

    Currently to perform proton magnetic resonance spectroscopy (1H MRS) with single voxel spectroscopy (SVS) technique long and/or short echo time sequences are used in order to provide complementary information. PURPOSE: The aim of the study was to compare the usefulness of STEAM (time echo, TE, 20 ms

  18. Accurate classification of brain gliomas by discriminate dictionary learning based on projective dictionary pair learning of proton magnetic resonance spectra.

    Science.gov (United States)

    Adebileje, Sikiru Afolabi; Ghasemi, Keyvan; Aiyelabegan, Hammed Tanimowo; Saligheh Rad, Hamidreza

    2017-04-01

    Proton magnetic resonance spectroscopy is a powerful noninvasive technique that complements the structural images of cMRI, which aids biomedical and clinical researches, by identifying and visualizing the compositions of various metabolites within the tissues of interest. However, accurate classification of proton magnetic resonance spectroscopy is still a challenging issue in clinics due to low signal-to-noise ratio, overlapping peaks of metabolites, and the presence of background macromolecules. This paper evaluates the performance of a discriminate dictionary learning classifiers based on projective dictionary pair learning method for brain gliomas proton magnetic resonance spectroscopy spectra classification task, and the result were compared with the sub-dictionary learning methods. The proton magnetic resonance spectroscopy data contain a total of 150 spectra (74 healthy, 23 grade II, 23 grade III, and 30 grade IV) from two databases. The datasets from both databases were first coupled together, followed by column normalization. The Kennard-Stone algorithm was used to split the datasets into its training and test sets. Performance comparison based on the overall accuracy, sensitivity, specificity, and precision was conducted. Based on the overall accuracy of our classification scheme, the dictionary pair learning method was found to outperform the sub-dictionary learning methods 97.78% compared with 68.89%, respectively. Copyright © 2016 John Wiley & Sons, Ltd.

  19. The reproducibility of quantitative measurements in lumbar magnetic resonance imaging of children from the general population

    DEFF Research Database (Denmark)

    Masharawi, Y; Kjær, Per; Bendix, T

    2008-01-01

    STUDY DESIGN: Quantitative lumbar magnetic resonance imaging (MRI) measurements in children were taken twice and analyzed for intra- and intertester reproducibility. OBJECTIVE: To evaluate the reproducibility of a variety of lumbar quantitative measurements taken from MRIs of children from the ge...

  20. An equivalent magnetic dipoles model for quantitative damage recognition of broken wire

    Institute of Scientific and Technical Information of China (English)

    TAN Ji-wen; ZHAN Wei-xia; LI Chun-jing; WEN Yan; SHU Jie

    2005-01-01

    By simplifying saturatedly magnetized wire-rope to magnetic dipoles of the same magnetic field strength, an equivalent magnetic dipoles model is developed and the measuring principle for recognising damage of broken wire was presented. The relevant calculation formulas were also deduced. A composite solution method about nonlinear optimization was given. An example was given to illustrate the use of the equivalent magnetic dipoles method for quantitative damage recognition, and demonstrates that the result of this method is consistent with the real situation, so the method is valid and practical.

  1. Current and emerging quantitative magnetic resonance imaging methods for assessing and predicting the response of breast cancer to neoadjuvant therapy

    Directory of Open Access Journals (Sweden)

    Abramson RG

    2012-10-01

    Full Text Available Richard G Abramson,1,2,9 Lori R Arlinghaus,1,2 Jared A Weis,1,2 Xia Li,1,2 Adrienne N Dula,1,2 Eduard Y Chekmenev,1–4,9 Seth A Smith,1–3,5 Michael I Miga,1–3,6 Vandana G Abramson,7,9 Thomas E Yankeelov1–3,5,8,91Institute of Imaging Science, 2Department of Radiology and Radiological Sciences, 3Department of Biomedical Engineering, 4Department of Biochemistry, 5Department of Physics, 6Department of Neurosurgery, 7Department of Medical Oncology, 8Department of Cancer Biology, 9Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville,TN, USAAbstract: Reliable early assessment of breast cancer response to neoadjuvant therapy (NAT would provide considerable benefit to patient care and ongoing research efforts, and demand for accurate and noninvasive early-response biomarkers is likely to increase. Response assessment techniques derived from quantitative magnetic resonance imaging (MRI hold great potential for integration into treatment algorithms and clinical trials. Quantitative MRI techniques already available for assessing breast cancer response to neoadjuvant therapy include lesion size measurement, dynamic contrast-enhanced MRI, diffusion-weighted MRI, and proton magnetic resonance spectroscopy. Emerging yet promising techniques include magnetization transfer MRI, chemical exchange saturation transfer MRI, magnetic resonance elastography, and hyperpolarized MR. Translating and incorporating these techniques into the clinical setting will require close attention to statistical validation methods, standardization and reproducibility of technique, and scanning protocol design.Keywords: treatment response, presurgical treatment, neoadjuvant chemotherapy

  2. Quantitative characterization of magnetic separators: Comparison of systems with and without integrated microfluidic mixers

    DEFF Research Database (Denmark)

    Lund-Olesen, Torsten; Bruus, Henrik; Hansen, Mikkel Fougt

    2006-01-01

    We present two new types of microfluidic passive magnetic bead separator systems as well as methods for performing quantitative characterizations of them. Both systems consist of a microfluidic channel with long rectangular magnetic elements of permalloy that are placed by the sides of the channe...

  3. DIRAC detector experiment: the vacuum chamber (blue), beginning of the flat chamber (yellow), magnetic screen (orange) in front of the magnet. The vacuum tube for the primary proton beam is below (sil ver color)

    CERN Multimedia

    Patrice Loïez

    1999-01-01

    DIRAC detector experiment: the vacuum chamber (blue), beginning of the flat chamber (yellow), magnetic screen (orange) in front of the magnet. The vacuum tube for the primary proton beam is below (sil ver color)

  4. Advanced quantitative magnetic nondestructive evaluation methods - Theory and experiment

    Science.gov (United States)

    Barton, J. R.; Kusenberger, F. N.; Beissner, R. E.; Matzkanin, G. A.

    1979-01-01

    The paper reviews the scale of fatigue crack phenomena in relation to the size detection capabilities of nondestructive evaluation methods. An assessment of several features of fatigue in relation to the inspection of ball and roller bearings suggested the use of magnetic methods; magnetic domain phenomena including the interaction of domains and inclusions, and the influence of stress and magnetic field on domains are discussed. Experimental results indicate that simplified calculations can be used to predict many features of these results; the data predicted by analytic models which use finite element computer analysis predictions do not agree with respect to certain features. Experimental analyses obtained on rod-type fatigue specimens which show experimental magnetic measurements in relation to the crack opening displacement and volume and crack depth should provide methods for improved crack characterization in relation to fracture mechanics and life prediction.

  5. An improved permanent magnet quadrupole design with larger good field region for high intensity proton linacs

    Energy Technology Data Exchange (ETDEWEB)

    Mathew, Jose V., E-mail: josev.mathew@gmail.com; Rao, S.V.L.S.; Krishnagopal, S.; Singh, P.

    2013-11-01

    The Low Energy High Intensity Proton Accelerator (LEHIPA), being developed at the Bhabha Atomic Research Centre (BARC) will produce a 20 MeV, 30 mA, continuous wave (CW) proton beam. At these low velocities, space-charge forces dominate, and could lead to larger beam sizes and beam halos. Hence in the design of the focusing lattice of the LEHIPA drift tube linac (DTL) using permanent magnet quadrupoles (PMQs), a larger good field region is preferred. Here we study, using the two dimensional (2D) and three dimensional (3D) simulation codes PANDIRA and RADIA, four different types of cylindrical PMQ designs: 16-segment trapezoidal Halbach configuration, bullet-nosed geometry and 8- and 16-segment rectangular geometries. The trapezoidal Halbach geometry is used in a variety of accelerators since it provides very high field gradients in small bores, while the bullet-nosed geometry, which is a combination of the trapezoidal and rectangular designs, is used in some DTLs. This study shows that a larger good field region is possible in the 16-segment rectangular design as compared to the Halbach and bullet-nosed designs, making it more attractive for high-intensity proton linacs. An improvement in good-field region by ∼16% over the Halbach design is obtained in the optimized 16-segment rectangular design, although the field gradient is lower by ∼20%. Tolerance studies show that the rectangular segment PMQ design is substantially less sensitive to the easy axis orientation errors and hence will be a better choice for DTLs. -- Highlights: • An improved permanent magnet quadrupole (PMQ) design with larger good field region is proposed. • We investigate four PMQ designs, including the widely used Halbach and bullet nosed designs. • Analytical calculations are backed by 2D as well as 3D numerical solvers, PANDIRA and RADIA. • The optimized 16 segment rectangular PMQ design is identified to exhibit the largest good field region. • The effect of easy axis orientation

  6. Magnetic field turbulence, electron heating, magnetic holes, proton cyclotron waves, and the onsets of bipolar pulse (electron hole events: a possible unifying scenario

    Directory of Open Access Journals (Sweden)

    B. T. Tsurutani

    2003-01-01

    Full Text Available Two electron heating events have been identified on 20 May 1996 when Polar was in the polar cap/polar cusp boundary layer. The electron heating events were located within magnetic holes/cavities/bubbles and were accompanied by nonlinear ± 14 nT peak-to-peak (f ~ 0.6 to 0.7 fcp obliquely propagating proton cyclotron waves. The electrons appear to be heated isotropically. Electric bipolar pulse (electron hole onset events were also detected within the heating events. We propose a scenario which can link the above phenomena. Nonlinear Alfvén waves, generated through cusp magnetic reconnection, propagate down magnetic field lines and locally heat electrons through the ponderomotive force. The magnetic cavity is created through the diamagnetic effect of the heated electrons. Ion heating also occurs through ponderomotive acceleration (but much less than the electrons and the protons generate the electromagnetic proton cyclotron waves through the loss cone instability. The obliquely propagating electromagnetic proton cyclotron waves accelerate bi-streaming electrons, which are the source of free energy for the electron holes.

  7. In vivo quantitation of metabolite concentrations in the brain by means of proton MRS

    DEFF Research Database (Denmark)

    Henriksen, O

    1995-01-01

    MRS offers unique possibilities for non-invasive studies of biochemistry in the human brain in vivo. A growing body of evidence suggests that proton MRS may contribute to the clinical evaluation of a number of pathologies including ischaemia, tumours, epilepsy, metabolic and neuropaediatric...... (NAA), total creatine, choline containing compounds, (Cho) and inositols (Ins). Internal standards (unsaturated water signal) as well as external standards have been used for signal calibration. Quality control with respect to signal linearity with concentration or with size of selected volume......, selection efficiency, outer volume depression and signal contamination is essential for validation of the measurements. Furthermore, corrections for the influence of relaxation behavior are necessary. The results published so far indicate that the concentrations of NAA, total creatine, Cho and Ins in mmoles...

  8. A new method for true quantitative elemental imaging using PIXE and the proton microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, C.G. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience; Jamieson, D.N. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Churms, C.L.; Pilcher, J.V. [National Accelerator Centre, Faure (South Africa)

    1993-12-31

    Traditional methods for X-ray imaging using PIXE and the Proton Microprobe have used a simple gate set on an X-ray peak in a spectrum from a Si(Li) detector to provide an image of the distribution of an element. This method can produce artefacts in images, due to overlapping X-ray lines from interfering elements, charge collection tails on peaks, background variation, Si escape peaks and pileup, all of which can render images misleading or qualitative at best. To address this problem, a matrix transform method has been developed at the CSIRO which not only eliminates most artefacts, but can be implemented on-line. The method has been applied to study trace gold distribution in a complex gold bearing ore from Fiji , and more recently has been installed for direct on-line elemental imaging at the NAC in South Africa. 4 refs., 2 figs.

  9. A processing method enabling the use of peak height for accurate and precise proton NMR quantitation.

    Science.gov (United States)

    Hays, Patrick A; Thompson, Robert A

    2009-10-01

    In NMR, peak area quantitation is the most common method used because the area under a peak or peak group is proportional to the number of nuclei at those frequencies. Peak height quantitation has not enjoyed as much utility because of poor precision and linearity as a result of inconsistent shapes and peak widths (measured at half height). By using a post-acquisition processing method employing a Gaussian or line-broadening (exponential decay) apodization (i.e. weighting function) to normalize the shape and width of the internal standard (ISTD) peak, the heights of an analyte calibration spectrum can be compared to the analyte peaks in a sample spectrum resulting in accurate and precise quantitative results. Peak height results compared favorably with 'clean' peak area results for several hundred illicit samples of methamphetamine HCl, cocaine HCl, and heroin HCl, of varying composition and purity. Using peak height and peak area results together can enhance the confidence in the reported purity value; a major advantage in high throughput, automated quantitative analyses. Published in 2009 by John Wiley & Sons, Ltd.

  10. Search for magnetic monopoles with the MoEDAL forward trapping detector in 13 TeV proton-proton collisions at the LHC

    CERN Document Server

    Acharya, B.; Baines, S.; Benes, P.; Bergmann, B.; Bernabéu, J.; Branzas, H.; Campbell, M.; Caramete, L.; Cecchini, S.; de Montigny, M.; De Roeck, A.; Ellis, J.R.; Fairbairn, M.; Felea, D.; Flores, J.; Frank, M.; Frekers, D.; Garcia, C.; Hirt, A.M.; Janecek, J.; Kalliokoski, M.; Katre, A.; Kim, D.-W.; Kinoshita, K.; Korzenev, A.; Lacarrère, D.H.; Lee, S.C.; Leroy, C.; Lionti, A.; Mamuzic, J.; Margiotta, A.; Mauri, N.; Mavromatos, N.E.; Mermod, P.; Mitsou, V.A.; Orava, R.; Parker, B.; Pasqualini, L.; Patrizii, L.; Păvălaş, G.E.; Pinfold, J.L.; Popa, V.; Pozzato, M.; Pospisil, S.; Rajantie, A.; Ruiz de Austri, R.; Sahnoun, Z.; Sakellariadou, M.; Sarkar, S.; Semenoff, G.; Shaa, A.; Sirri, G.; Sliwa, K.; Soluk, R.; Spurio, M.; Srivastava, Y.N.; Suk, M.; Swain, J.; Tenti, M.; Togo, V.; Tuszyński, J.A.; Vento, V.; Vives, O.; Vykydal, Z.; Whyntie, T.; Widom, A.; Willems, G.; Yoon, J.H.; Zgura, I.S.

    2017-02-10

    MoEDAL is designed to identify new physics in the form of long-lived highly-ionising particles produced in high-energy LHC collisions. Its arrays of plastic nuclear-track detectors and aluminium trapping volumes provide two independent passive detection techniques. We present here the results of a search for magnetic monopole production in 13 TeV proton-proton collisions using the trapping technique, extending a previous publication with 8~TeV data during LHC run-1. A total of 222~kg of MoEDAL trapping detector samples were exposed in the forward region and analysed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges exceeding half the Dirac charge are excluded in all samples and limits are placed for the first time on the production of magnetic monopoles in 13 TeV collisions. The search probes mass ranges previously inaccessible to collider experiments for up to five times the Dirac charge.

  11. Search for Magnetic Monopoles with the MoEDAL Forward Trapping Detector in 13 TeV Proton-Proton Collisions at the LHC

    Science.gov (United States)

    Acharya, B.; Alexandre, J.; Baines, S.; Benes, P.; Bergmann, B.; Bernabéu, J.; Branzas, H.; Campbell, M.; Caramete, L.; Cecchini, S.; de Montigny, M.; De Roeck, A.; Ellis, J. R.; Fairbairn, M.; Felea, D.; Flores, J.; Frank, M.; Frekers, D.; Garcia, C.; Hirt, A. M.; Janecek, J.; Kalliokoski, M.; Katre, A.; Kim, D.-W.; Kinoshita, K.; Korzenev, A.; Lacarrère, D. H.; Lee, S. C.; Leroy, C.; Lionti, A.; Mamuzic, J.; Margiotta, A.; Mauri, N.; Mavromatos, N. E.; Mermod, P.; Mitsou, V. A.; Orava, R.; Parker, B.; Pasqualini, L.; Patrizii, L.; Pǎvǎlaş, G. E.; Pinfold, J. L.; Popa, V.; Pozzato, M.; Pospisil, S.; Rajantie, A.; Ruiz de Austri, R.; Sahnoun, Z.; Sakellariadou, M.; Sarkar, S.; Semenoff, G.; Shaa, A.; Sirri, G.; Sliwa, K.; Soluk, R.; Spurio, M.; Srivastava, Y. N.; Suk, M.; Swain, J.; Tenti, M.; Togo, V.; Tuszyński, J. A.; Vento, V.; Vives, O.; Vykydal, Z.; Whyntie, T.; Widom, A.; Willems, G.; Yoon, J. H.; Zgura, I. S.; MoEDAL Collaboration

    2017-02-01

    MoEDAL is designed to identify new physics in the form of long-lived highly ionizing particles produced in high-energy LHC collisions. Its arrays of plastic nuclear-track detectors and aluminium trapping volumes provide two independent passive detection techniques. We present here the results of a first search for magnetic monopole production in 13 TeV proton-proton collisions using the trapping technique, extending a previous publication with 8 TeV data during LHC Run 1. A total of 222 kg of MoEDAL trapping detector samples was exposed in the forward region and analyzed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges exceeding half the Dirac charge are excluded in all samples and limits are placed for the first time on the production of magnetic monopoles in 13 TeV p p collisions. The search probes mass ranges previously inaccessible to collider experiments for up to five times the Dirac charge.

  12. Search for Magnetic Monopoles with the MoEDAL Forward Trapping Detector in 13 TeV Proton-Proton Collisions at the LHC.

    Science.gov (United States)

    Acharya, B; Alexandre, J; Baines, S; Benes, P; Bergmann, B; Bernabéu, J; Branzas, H; Campbell, M; Caramete, L; Cecchini, S; de Montigny, M; De Roeck, A; Ellis, J R; Fairbairn, M; Felea, D; Flores, J; Frank, M; Frekers, D; Garcia, C; Hirt, A M; Janecek, J; Kalliokoski, M; Katre, A; Kim, D-W; Kinoshita, K; Korzenev, A; Lacarrère, D H; Lee, S C; Leroy, C; Lionti, A; Mamuzic, J; Margiotta, A; Mauri, N; Mavromatos, N E; Mermod, P; Mitsou, V A; Orava, R; Parker, B; Pasqualini, L; Patrizii, L; Păvălaş, G E; Pinfold, J L; Popa, V; Pozzato, M; Pospisil, S; Rajantie, A; Ruiz de Austri, R; Sahnoun, Z; Sakellariadou, M; Sarkar, S; Semenoff, G; Shaa, A; Sirri, G; Sliwa, K; Soluk, R; Spurio, M; Srivastava, Y N; Suk, M; Swain, J; Tenti, M; Togo, V; Tuszyński, J A; Vento, V; Vives, O; Vykydal, Z; Whyntie, T; Widom, A; Willems, G; Yoon, J H; Zgura, I S

    2017-02-10

    MoEDAL is designed to identify new physics in the form of long-lived highly ionizing particles produced in high-energy LHC collisions. Its arrays of plastic nuclear-track detectors and aluminium trapping volumes provide two independent passive detection techniques. We present here the results of a first search for magnetic monopole production in 13 TeV proton-proton collisions using the trapping technique, extending a previous publication with 8 TeV data during LHC Run 1. A total of 222 kg of MoEDAL trapping detector samples was exposed in the forward region and analyzed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges exceeding half the Dirac charge are excluded in all samples and limits are placed for the first time on the production of magnetic monopoles in 13 TeV pp collisions. The search probes mass ranges previously inaccessible to collider experiments for up to five times the Dirac charge.

  13. Pion production via proton synchrotron radiation in strong magnetic fields in relativistic field theory: Scaling relations and angular distributions

    Science.gov (United States)

    Maruyama, Tomoyuki; Cheoun, Myung-Ki; Kajino, Toshitaka; Mathews, Grant J.

    2016-06-01

    We study pion production by proton synchrotron radiation in the presence of a strong magnetic field when the Landau numbers of the initial and final protons are ni,f ∼104-105. We find in our relativistic field theory calculations that the pion decay width depends only on the field strength parameter which previously was only conjectured based upon semi-classical arguments. Moreover, we also find new results that the decay width satisfies a robust scaling relation, and that the polar angular distribution of emitted pion momenta is very narrow and can be easily obtained. This scaling implies that one can infer the decay width in more realistic magnetic fields of 1015 G, where ni,f ∼1012-1013, from the results for ni,f ∼104-105. The resultant pion intensity and angular distributions for realistic magnetic field strengths are presented and their physical implications discussed.

  14. Magnetic fields and beam optics studies of a 250 MeV superconducting proton radiotherapy cyclotron

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong-Won [Research Institute and Hospital, National Cancer Center, 809 Madu-dong, Koyang, Kyonggi (Korea, Republic of)], E-mail: jwkim@ncc.re.kr

    2007-11-21

    A 250 MeV superconducting cyclotron for the proton radiation therapy was designed at the Michigan State University (MSU) for use at the Paul Scherrer Institut. This work was based on the conceptual design carried out at the MSU in 1994. The previous design was refined to finalize the magnet configuration and to optimally arrange cyclotron elements for the actual construction. The spiral angle of the pole was reduced, the new hill-edges and valley shims being introduced. The magnetic fields were highly isochronized using a least square fitting routine involving a schematic shimming scheme. The resulting reference field was adequate for the elaborate study of beam optics. The optics simulation predicted that extraction efficiency of above 80% was achievable for a beam with the initial phase width of 20{sup o}. The vertical deflector was investigated located in the central region to control the beam intensity with tracking of beam phase spaces. Some measurement results for the constructed cyclotron were found in a good agreement with those of the optics study.

  15. Electron Cloud Generation and Trapping in a Quadrupole Magnet at the Los Alamos Proton Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Macek, Robert J.; Browman, Andrew A.; Ledford, John E.; /TechSource, Santa Fe /Los Alamos; Borden, Michael J.; O' Hara, James F.; McCrady, Rodney C.; Rybarcyk, Lawrence J.; Spickermann, Thomas; Zaugg, Thomas J.; /Los Alamos; Pivi, Mauro T.F.; /SLAC

    2008-03-17

    Recent beam physics studies on the two-stream e-p instability at the LANL proton storage ring (PSR) have focused on the role of the electron cloud generated in quadrupole magnets where primary electrons, which seed beam-induced multipacting, are expected to be largest due to grazing angle losses from the beam halo. A new diagnostic to measure electron cloud formation and trapping in a quadrupole magnet has been developed, installed, and successfully tested at PSR. Beam studies using this diagnostic show that the 'prompt' electron flux striking the wall in a quadrupole is comparable to the prompt signal in the adjacent drift space. In addition, the 'swept' electron signal, obtained using the sweeping feature of the diagnostic after the beam was extracted from the ring, was larger than expected and decayed slowly with an exponential time constant of 50 to 100 {micro}s. Other measurements include the cumulative energy spectra of prompt electrons and the variation of both prompt and swept electron signals with beam intensity. Experimental results were also obtained which suggest that a good fraction of the electrons observed in the adjacent drift space for the typical beam conditions in the 2006 run cycle were seeded by electrons ejected from the quadrupole.

  16. Quantitative velocity distributions via nuclear magnetic resonance flow metering

    Science.gov (United States)

    O'Neill, Keelan T.; Fridjonsson, Einar O.; Stanwix, Paul L.; Johns, Michael L.

    2016-08-01

    We demonstrate the use of Tikhonov regularisation as a data inversion technique to determine the velocity distributions of flowing liquid streams. Regularisation is applied to the signal produced by a nuclear magnetic resonance (NMR) flow measurement system consisting of a pre-polarising permanent magnet located upstream of an Earth's magnetic field NMR detection coil. A simple free induction decay (FID) NMR signal is measured for the flowing stream in what is effectively a 'time-of-flight' measurement. The FID signal is then modelled as a function of fluid velocity and acquisition time, enabling determination of the velocity probability distributions via regularisation. The mean values of these velocity distributions were successfully validated against in-line rotameters. The ability to quantify multi-modal velocity distributions was also demonstrated using a two-pipe system.

  17. Collective relaxation of protein protons at very low magnetic field: a new window on protein dynamics and aggregation.

    Science.gov (United States)

    Luchinat, Claudio; Parigi, Giacomo

    2007-02-07

    Since the recent availability of high sensitivity field-cycling relaxometers, it has become possible to measure the protein proton relaxation in millimolar protein solutions as a function of magnetic field. In principle, this provides direct access to the so-called spectral density function of protein protons and, hence, to a full set of dynamic parameters. Understanding the dynamic behavior of biological molecules is increasingly appreciated as crucial to understanding their function. However, theoretical tools to analyze the collective relaxation behavior of protons in solute macromolecules over a wide range of magnetic fields are lacking. A complete relaxation matrix analysis of such behavior is described here. This analysis provides excellent predictions of the experimental proton magnetization decays/recoveries-measured to an unprecedented level of accuracy by a last-generation fast field-cycling relaxometer-of two different globular proteins, hen egg white lysozyme and human serum albumin. The new experimentally validated theoretical model is then used to extract dynamic information on these systems. A "collective" order parameter SC2, different from, but complementary to, that commonly extracted from heteronuclear relaxation measurements at high field, is defined and measured. An accurate estimate of the rotational correlation time is obtained: in the case of lysozyme it agrees very well with theoretical predictions; in the case of serum albumin it provides evidence for aggregation at millimolar concentration.

  18. Quantitative in situ magnetization reversal studies in Lorentz microscopy and electron holography.

    Science.gov (United States)

    Rodríguez, L A; Magén, C; Snoeck, E; Gatel, C; Marín, L; Serrano-Ramón, L; Prieto, J L; Muñoz, M; Algarabel, P A; Morellon, L; De Teresa, J M; Ibarra, M R

    2013-11-01

    A generalized procedure for the in situ application of magnetic fields by means of the excitation of the objective lens for magnetic imaging experiments in Lorentz microscopy and electron holography is quantitatively described. A protocol for applying magnetic fields with arbitrary in-plane magnitude and orientation is presented, and a freeware script for Digital Micrograph(™) is provided to assist the operation of the microscope. Moreover, a method to accurately reconstruct hysteresis loops is detailed. We show that the out-of-plane component of the magnetic field cannot be always neglected when performing quantitative measurements of the local magnetization. Several examples are shown to demonstrate the accuracy and functionality of the methods. © 2013 Elsevier B.V. All rights reserved.

  19. Ultrasound imaging for quantitative evaluation of magnetic density separation

    NARCIS (Netherlands)

    Sanaee, S.A.

    2013-01-01

    This thesis is dedicated to an investigation of the potential and technological possibilities of an inline ultrasound system as a quality control system for wet recycling of solid waste. The main targeted recycling technology is magnetic density separation (MDS), a novel technique that was

  20. Ultrasound imaging for quantitative evaluation of magnetic density separation

    NARCIS (Netherlands)

    Sanaee, S.A.

    2013-01-01

    This thesis is dedicated to an investigation of the potential and technological possibilities of an inline ultrasound system as a quality control system for wet recycling of solid waste. The main targeted recycling technology is magnetic density separation (MDS), a novel technique that was investiga

  1. Application of magnetic carriers to two examples of quantitative cell analysis

    Science.gov (United States)

    Zhou, Chen; Qian, Zhixi; Choi, Young Suk; David, Allan E.; Todd, Paul; Hanley, Thomas R.

    2017-04-01

    The use of magnetophoretic mobility as a surrogate for fluorescence intensity in quantitative cell analysis was investigated. The objectives of quantitative fluorescence flow cytometry include establishing a level of labeling for the setting of parameters in fluorescence activated cell sorters (FACS) and the determination of levels of uptake of fluorescently labeled substrates by living cells. Likewise, the objectives of quantitative magnetic cytometry include establishing a level of labeling for the setting of parameters in flowing magnetic cell sorters and the determination of levels of uptake of magnetically labeled substrates by living cells. The magnetic counterpart to fluorescence intensity is magnetophoretic mobility, defined as the velocity imparted to a suspended cell per unit of magnetic ponderomotive force. A commercial velocimeter available for making this measurement was used to demonstrate both applications. Cultured Gallus lymphoma cells were immunolabeled with commercial magnetic beads and shown to have adequate magnetophoretic mobility to be separated by a novel flowing magnetic separator. Phagocytosis of starch nanoparticles having magnetic cores by cultured Chinese hamster ovary cells, a CHO line, was quantified on the basis of magnetophoretic mobility.

  2. Quantitative evaluation of magnetic flux density in a magnetic recording head and pseudo soft underlayer by electron holography.

    Science.gov (United States)

    Xia, Weixing; Hirata, Kei; Yanagisawa, Keiichi; Ishida, Yoichi; Kasai, Hiroto; Yanagiuchi, Katsuaki; Shindo, Daisuke; Tonomura, Akira

    2010-01-01

    The magnetic interaction between the pole tip of a single-pole head and a pseudo soft underlayer in perpendicular magnetic recording was observed by electron holography. The magnetic flux density inside the soft underlayer was quantitatively evaluated. The distribution of magnetic flux density was calculated using the finite element method, and the influences of the modulation of the reference wave and stray fields were investigated by comparison with experimental results. The flux density observed was found to be underestimated due to the modulation of the phase shift in reference wave. The magnetic flux measured experimentally was larger than that inside the specimen because of the relatively large stray fields above and below the specimen in the direction of the electron beam.

  3. Proton Nuclear Magnetic Resonance-Spectroscopic Discrimination of Wines Reflects Genetic Homology of Several Different Grape (V. vinifera L.) Cultivars

    Science.gov (United States)

    Zhu, Yong; Wen, Wen; Zhang, Fengmin; Hardie, Jim W.

    2015-01-01

    Background and Aims Proton nuclear magnetic resonance spectroscopy coupled multivariate analysis (1H NMR-PCA/PLS-DA) is an important tool for the discrimination of wine products. Although 1H NMR has been shown to discriminate wines of different cultivars, a grape genetic component of the discrimination has been inferred only from discrimination of cultivars of undefined genetic homology and in the presence of many confounding environmental factors. We aimed to confirm the influence of grape genotypes in the absence of those factors. Methods and Results We applied 1H NMR-PCA/PLS-DA and hierarchical cluster analysis (HCA) to wines from five, variously genetically-related grapevine (V. vinifera) cultivars; all grown similarly on the same site and vinified similarly. We also compared the semi-quantitative profiles of the discriminant metabolites of each cultivar with previously reported chemical analyses. The cultivars were clearly distinguishable and there was a general correlation between their grouping and their genetic homology as revealed by recent genomic studies. Between cultivars, the relative amounts of several of the cultivar-related discriminant metabolites conformed closely with reported chemical analyses. Conclusions Differences in grape-derived metabolites associated with genetic differences alone are a major source of 1H NMR-based discrimination of wines and 1H NMR has the capacity to discriminate between very closely related cultivars. Significance of the Study The study confirms that genetic variation among grape cultivars alone can account for the discrimination of wine by 1H NMR-PCA/PLS and indicates that 1H NMR spectra of wine of single grape cultivars may in future be used in tandem with hierarchical cluster analysis to elucidate genetic lineages and metabolomic relations of grapevine cultivars. In the absence of genetic information, for example, where predecessor varieties are no longer extant, this may be a particularly useful approach. PMID

  4. Quantitative prediction of radio frequency induced local heating derived from measured magnetic field maps in magnetic resonance imaging: A phantom validation at 7 T

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaotong; Liu, Jiaen [Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Van de Moortele, Pierre-Francois; Schmitter, Sebastian [Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota 55455 (United States); He, Bin, E-mail: binhe@umn.edu [Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Institute for Engineering in Medicine, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    2014-12-15

    Electrical Properties Tomography (EPT) technique utilizes measurable radio frequency (RF) coil induced magnetic fields (B1 fields) in a Magnetic Resonance Imaging (MRI) system to quantitatively reconstruct the local electrical properties (EP) of biological tissues. Information derived from the same data set, e.g., complex numbers of B1 distribution towards electric field calculation, can be used to estimate, on a subject-specific basis, local Specific Absorption Rate (SAR). SAR plays a significant role in RF pulse design for high-field MRI applications, where maximum local tissue heating remains one of the most constraining limits. The purpose of the present work is to investigate the feasibility of such B1-based local SAR estimation, expanding on previously proposed EPT approaches. To this end, B1 calibration was obtained in a gelatin phantom at 7 T with a multi-channel transmit coil, under a particular multi-channel B1-shim setting (B1-shim I). Using this unique set of B1 calibration, local SAR distribution was subsequently predicted for B1-shim I, as well as for another B1-shim setting (B1-shim II), considering a specific set of parameter for a heating MRI protocol consisting of RF pulses plaid at 1% duty cycle. Local SAR results, which could not be directly measured with MRI, were subsequently converted into temperature change which in turn were validated against temperature changes measured by MRI Thermometry based on the proton chemical shift.

  5. Quantitative in situ magnetization reversal studies in Lorentz microscopy and electron holography

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez, L.A. [Laboratorio de Microscopías Avanzadas (LMA), Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, 50018 Zaragoza (Spain); Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza (Spain); Transpyrenean Associated Laboratory for Electron Microscopy (TALEM), CEMES-INA, CNRS-Universidad de Zaragoza, Toulouse (France); CEMES-CNRS 29, rue Jeanne Marvig, B.P. 94347, F-31055 Toulouse Cedex (France); Magén, C., E-mail: cmagend@unizar.es [Laboratorio de Microscopías Avanzadas (LMA), Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, 50018 Zaragoza (Spain); Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza (Spain); Transpyrenean Associated Laboratory for Electron Microscopy (TALEM), CEMES-INA, CNRS-Universidad de Zaragoza, Toulouse (France); Fundación ARAID, 50018 Zaragoza (Spain); Snoeck, E.; Gatel, C. [Transpyrenean Associated Laboratory for Electron Microscopy (TALEM), CEMES-INA, CNRS-Universidad de Zaragoza, Toulouse (France); CEMES-CNRS 29, rue Jeanne Marvig, B.P. 94347, F-31055 Toulouse Cedex (France); Marín, L. [Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza (Spain); Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, 50018 Zaragoza (Spain); Serrano-Ramón, L. [Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza (Spain); Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, 50009 Zaragoza (Spain); and others

    2013-11-15

    A generalized procedure for the in situ application of magnetic fields by means of the excitation of the objective lens for magnetic imaging experiments in Lorentz microscopy and electron holography is quantitatively described. A protocol for applying magnetic fields with arbitrary in-plane magnitude and orientation is presented, and a freeware script for Digital Micrograph{sup ™} is provided to assist the operation of the microscope. Moreover, a method to accurately reconstruct hysteresis loops is detailed. We show that the out-of-plane component of the magnetic field cannot be always neglected when performing quantitative measurements of the local magnetization. Several examples are shown to demonstrate the accuracy and functionality of the methods. - Highlights: • Generalized procedure for application of magnetic fields with the TEM objective lens. • Arbitrary in-plane magnetic field magnitude and orientation can be applied. • Method to accurately reconstruct hysteresis loops by electron holography. • Out-of-plane field component should be considered in quantitative measurements. • Examples to illustrate the method in Lorentz microscopy and electron holography.

  6. Direct measurement of kilo-tesla level magnetic field generated with laser-driven capacitor-coil target by proton deflectometry

    Science.gov (United States)

    Law, K. F. F.; Bailly-Grandvaux, M.; Morace, A.; Sakata, S.; Matsuo, K.; Kojima, S.; Lee, S.; Vaisseau, X.; Arikawa, Y.; Yogo, A.; Kondo, K.; Zhang, Z.; Bellei, C.; Santos, J. J.; Fujioka, S.; Azechi, H.

    2016-02-01

    A kilo-tesla level, quasi-static magnetic field (B-field), which is generated with an intense laser-driven capacitor-coil target, was measured by proton deflectometry with a proper plasma shielding. Proton deflectometry is a direct and reliable method to diagnose strong, mm3-scale laser-produced B-field; however, this was not successful in the previous experiment. A target-normal-sheath-accelerated proton beam is deflected by Lorentz force in the laser-produced magnetic field with the resulting deflection pattern recorded on a radiochromic film stack. A 610 ± 30 T of B-field amplitude was inferred by comparing the experimental proton pattern with Monte-Carlo calculations. The amplitude and temporal evolutions of the laser-generated B-field were also measured by a differential magnetic probe, independently confirming the proton deflectometry measurement results.

  7. Why baryons are Yang-Mills magnetic monopoles, validated by nuclear binding energies and proton and neutron masses

    Science.gov (United States)

    Yablon, Jay R.

    2013-10-01

    Evidence is summarized from four recent papers that baryons including protons and neutrons are magnetic monopoles of non-commuting Yang-Mills gauge theories: 1) Protons and neutrons are ``resonant cavities'' with binding energies determined strictly by the masses of the quarks they contain. This is proven true at parts-per million accuracy for each of the 2H, 3H,3He, 4He binding energies and the neutron minus proton mass difference. 2) Respectively, each free proton and neutron contains 7.64 MeV and 9.81 MeV of mass/energy used to confine its quarks. When these nucleons bind, some, never all, of this energy is released and the mass deficit goes into binding. The balance continues to confine quarks. 56Fe releases 99.8429% of this energy for binding, more than any other nuclide. 3) Once we consider the Fermi vev one also finds an entirely theoretical explanation of proton and neutron masses, which also connects within experimental errors to the CKM quark mixing angles. 4) A related GUT explains fermion generation replication based on generator loss during symmetry breaking, and answers Rabi's question ``who ordered this?'' 5) Nuclear physics is governed by combining Maxwell's two classical equations into one equation using non-commuting gauge fields in view of Dirac theory and Fermi-Dirac-Pauli Exclusion. 6) Atoms themselves are core magnetic charges (nucleons) paired with orbital electric charges (electrons and elusive neutrinos), with the periodic table itself revealing an electric/magnetic symmetry of Maxwell's equations often pondered but heretofore unrecognized for a century and a half.

  8. Iron filled carbon nanotubes as novel monopole-like sensors for quantitative magnetic force microscopy

    Science.gov (United States)

    Wolny, F.; Mühl, T.; Weissker, U.; Lipert, K.; Schumann, J.; Leonhardt, A.; Büchner, B.

    2010-10-01

    We present a novel ultrahigh stability sensor for quantitative magnetic force microscopy (MFM) based on an iron filled carbon nanotube. In contrast to the complex magnetic structure of conventional MFM probes, this sensor constitutes a nanomagnet with defined properties. The long iron nanowire can be regarded as an extended dipole of which only the monopole close to the sample surface is involved in the imaging process. We demonstrate its potential for high resolution imaging. Moreover, we present an easy routine to determine its monopole moment and prove that this calibration, unlike other approaches, is universally applicable. For the first time this enables straightforward quantitative MFM measurements.

  9. Quantitatively analyzing intrinsic plasmonic chirality by tracking the interplay of electric and magnetic dipole modes

    CERN Document Server

    Hu, Li; Fang, Yurui

    2016-01-01

    Plasmonic chirality exhibits great potential for novel nanooptical devices due to the generation of a strong chiroptical response. Previous reports on plasmonic chirality explanations are mainly based on phase retardation and coupling. We propose a quantitative model similar to the chiral molecules for explaining the mechanism of the intrinsic plasmonic chirality quantitatively based on the interplay and mixing of electric and magnetic dipole modes, which forms a mixed electric and magnetic polarizability. The analysis method is also suitable for small chiral object down to quasi-static limit without phase delay and expected to be a universal rule.

  10. Magnetization Transfer and Amide Proton Transfer MRI of Neonatal Brain Development

    Directory of Open Access Journals (Sweden)

    Yang Zheng

    2016-01-01

    Full Text Available Purpose. This study aims to evaluate the process of brain development in neonates using combined amide proton transfer (APT imaging and conventional magnetization transfer (MT imaging. Materials and Methods. Case data were reviewed for all patients hospitalized in our institution’s neonatal ward. Patients underwent APT and MT imaging (a single protocol immediately following the routine MR examination. Single-slice APT/MT axial imaging was performed at the level of the basal ganglia. APT and MT ratio (MTR measurements were performed in multiple brain regions of interest (ROIs. Data was statistically analyzed in order to assess for significant differences between the different regions of the brain or correlation with patient gestational age. Results. A total of 38 neonates were included in the study, with ages ranging from 27 to 41 weeks’ corrected gestational age. There were statistically significant differences in both APT and MTR measurements between the frontal lobes, basal ganglia, and occipital lobes (APT: frontal lobe versus occipital lobe P=0.031 and other groups P=0.00; MTR: frontal lobe versus occipital lobe P=0.034 and other groups P=0.00. Furthermore, APT and MTR in above brain regions exhibited positive linear correlations with patient gestational age. Conclusions. APT/MT imaging can provide valuable information about the process of the neonatal brain development at the molecular level.

  11. Proton magnetic resonance with parahydrogen induced polarization. Imaging strategies and continuous generation

    Energy Technology Data Exchange (ETDEWEB)

    Dechent, Jan Falk Frederik

    2012-12-17

    A major challenge in imaging is the detection of small amounts of molecules of interest. In the case of magnetic resonance imaging (MRI) their signals are typically concealed by the large background signal of e.g. the tissue of the body. This problem can be tackled by hyperpolarization which increases the NMR signals up to several orders of magnitude. However, this strategy is limited for {sup 1}H, the most widely used nucleus in NMR and MRI, because the enormous number of protons in the body screen the small amount of hyperpolarized ones. Here, I describe a method giving rise to high {sup 1}H MRI contrast for hyperpolarized molecules against a large background signal. The contrast is based on the J-coupling induced rephasing of the NMR signal of molecules hyperpolarized via parahydrogen induce polarization (PHIP) and it can easily be implemented in common pulse sequences. Hyperpolarization methods typically require expensive technical equipment (e.g. lasers or microwaves) and most techniques work only in batch mode, thus the limited lifetime of the hyperpolarization is limiting its applications. Therefore, the second part of my thesis deals with the simple and efficient generation of an hyperpolarization. These two achievements open up alternative opportunities to use the standard MRI nucleus {sup 1}H for e.g. metabolic imaging in the future.

  12. Fragile X syndrome: a pilot proton magnetic resonance spectroscopy study in premutation carriers

    LENUS (Irish Health Repository)

    Hallahan, Brian P

    2012-08-30

    AbstractPurposeThere is increasing evidence that neurodevelopmental differences in people with Fragile X syndrome (FraX) may be explained by differences in glutamatergic metabolism. Premutation carriers of FraX were originally considered to be unaffected although several recent reports demonstrate neuroanatomical, cognitive, and emotional differences from controls. However there are few studies on brain metabolism in premutation carriers of FraX.MethodsWe used proton magnetic resonance spectroscopy to compare neuronal integrity of a number of brain metabolites including N-Acetyl Aspartate, Creatine + Phosphocreatinine, Choline, myoInositol, and Glutamate containing substances (Glx) in 17 male premutation carriers of FraX and 16 male healthy control individuals.ResultsThere was no significant between-group difference in the concentration of any measured brain metabolites. However there was a differential increase in N-acetyl aspartate with aging in premutation FraX individuals compared to controls.ConclusionsThis is the first 1 H-MRS study to examine premutation FraX individuals. Although we demonstrated no difference in the concentration of any of the metabolites examined between the groups, this may be due to the large age ranges included in the two samples. The differential increase in NAA levels with aging may reflect an abnormal synaptic pruning process.

  13. Proton nuclear magnetic resonance spectroscopy based investigation on propylene glycol toxicosis in a Holstein cow

    Directory of Open Access Journals (Sweden)

    Raun Birgitte-Marie L

    2009-06-01

    Full Text Available Abstract Background It is unknown which metabolites are responsible for propylene glycol (PG-induced toxicosis, and a better understanding of the underlying mechanisms explaining incidences of abnormal behaviour of dairy cows fed PG is therefore needed. Methods The study included three cows of which one developed PG toxicosis. In order to investigate how the metabolism of PG differed in the cow developing toxicosis, proton nuclear magnetic resonance (NMR spectroscopy was applied on ruminal fluids and blood plasma samples obtained before and after feeding with PG. Results PG toxicosis was characterized by dyspnea and ruminal atony upon intake of concentrate containing PG. The oxygen saturation of arterial blood haemoglobin and the oxygen pressure in arterial blood decreased along with the appearance of the clinical symptoms. NMR revealed differences in plasma and ruminal content of several metabolites between the cow responding abnormally to PG and the two control cows. Conclusion It is concluded that PG-toxicosis is likely caused by pulmonary vasoconstriction, but no unusual metabolites directly related to induction of this condition could be detected in the plasma or the ruminal fluid.

  14. Proton magnetic resonance spectroscopy in children with fetal alcohol spectrum disorders

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Rita de Cassia Ferreira; Vasconcelos, Marcio Moacyr; Faleiros, Leticia Oliveira; Brito, Adriana Rocha; Werner Junior, Jairo; Herdy, Gesmar Volga Haddad [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Faculdade de Medicina], e-mail: rcgonc@hotmail.com; Cruz Junior, Luiz Celso Hygino da; Domingues, Romeu Cortes [Multi-Imagem, Rio de Janeiro, RJ (Brazil)

    2009-06-15

    To analyze the metabolic constitution of brain areas through proton magnetic resonance spectroscopy in children affected with fetal alcohol spectrum disorder compared with normal children. Method: The sample of this case-control study included eight boys with epidemiologic history of in utero exposure to alcohol (median age 13.6{+-}3.8 years) who were diagnosed with fetal alcohol spectrum disorder, and eight controls (median age 12.1{+-}3,4 years). An 8 cm{sup 3} single voxel approach was used, with echo time 30 ms, repetition time 1500 ms, and 128 acquisitions in a 1.5T scanner, and four brain areas were analyzed: anterior cingulate, left frontal lobe, left striatum, and left cerebellar hemisphere. Peaks and ratios of metabolites N-acetylaspartate, choline, creatine, and myo-inositol were measured. Results: Children with fetal alcohol spectrum disorder showed a decrease in choline/creatine ratio (p=0.020) in left striatum and an increase in myo-inositol/creatine ratio (p=0.048) in left cerebellum compared with controls. There was no statistically significant difference in all peaks and ratios from the anterior cingulate and frontal lobe between the two groups. Conclusion: This study found evidence that the left striatum and left cerebellum are affected by intrauterine exposure to alcohol. Additional studies with larger samples are necessary to expand our knowledge of the effects of fetal exposure to alcohol. (author)

  15. Nuclear magnetic resonance and proton relaxation times in experimental heterotopic heart transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Eugene, M.; Lechat, P.; Hadjiisky, P.; Teillac, A.; Grosgogeat, Y.; Cabrol, C.

    1986-01-01

    It should be possible to detect heart transplant rejection by nuclear magnetic resonance (NMR) imaging if it induces myocardial T1 and T2 proton relaxation time alterations or both. We studied 20 Lewis rats after a heterotopic heart transplantation. In vitro measurement of T1 and T2 was performed on a Minispec PC20 (Bruker) 3 to 9 days after transplantation. Histologic analysis allowed the quantification of rejection process based on cellular infiltration and myocardiolysis. Water content, a major determinant of relaxation time, was also studied. T1 and T2 were significantly prolonged in heterotopic vs orthotopic hearts (638 +/- 41 msec vs 606 +/- 22 msec for T1, p less than 0.01 and 58.2 +/- 8.4 msec vs 47.4 +/- 1.9 msec for T2, p less than 0.001). Water content was also increased in heterotopic hearts (76.4 +/- 2.3 vs 73.8 +/- 1.0, p less than 0.01). Most importantly, we found close correlations between T1 and especially T2 vs water content, cellular infiltration, and myocardiolysis. We conclude that rejection reaction should be noninvasively detected by NMR imaging, particularly with pulse sequences emphasizing T2.

  16. High-resolution proton nuclear magnetic resonance spectroscopy of ovarian cyst fluid.

    Science.gov (United States)

    Boss, E A; Moolenaar, S H; Massuger, L F; Boonstra, H; Engelke, U F; de Jong, J G; Wevers, R A

    2000-08-01

    Most ovarian tumors are cystic structures containing variable amounts of fluid. Several studies of ovarian cyst fluid focus on one specific metabolite using conventional assay systems. We examined the potential of (1)H-nuclear magnetic resonance spectroscopy in evaluation of the overall metabolic composition of cyst fluid from different ovarian tumors. Ovarian cyst fluid samples obtained from 40 patients with a primary ovarian tumor (12 malignant and 28 benign) were examined. After deproteinization and pD standardization, we performed (1)H-NMR spectroscopy on a 600 MHz instrument. With (1)H-NMR spectroscopy we found detectable concentrations of 36 metabolites with high intersample variation. A number of unassigned resonances as well as unexpected metabolites were found. We introduce an overall inventory of the low-molecular-weight metabolites in ovarian cyst fluid with corresponding resonances. Significant differences in concentration (p overview of low-molecular-weight proton-containing metabolities present in ovarian cyst fluid samples. The metabolic composition of cyst fluid differs significantly between benign and malignant ovarian tumors. Furthermore, differences between benign subgroups possibly related to histopathological behaviour can be detected. The presence of N-acetyl aspartic acid and 5-oxoproline exclusively in serous cystadenoma samples is remarkable. Future studies will concentrate on these findings and explore the possibilities of extrapolating information from the in vitro studies to in vivo practice, in which metabolic differences between malignant and benign subtypes can be of great importance in a pre-operative phase.

  17. Characterization of urban aerosol using aerosol mass spectrometry and proton nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Cleveland, M. J.; Ziemba, L. D.; Griffin, R. J.; Dibb, J. E.; Anderson, C. H.; Lefer, B.; Rappenglück, B.

    2012-07-01

    Particulate matter was measured during August and September of 2006 in Houston as part of the Texas Air Quality Study II Radical and Aerosol Measurement Project. Aerosol size and composition were determined using an Aerodyne quadrupole aerosol mass spectrometer. Aerosol was dominated by sulfate (4.1 ± 2.6 μg m-3) and organic material (5.5 ± 4.0 μg m-3), with contributions of organic material from both primary (˜32%) and secondary (˜68%) sources. Secondary organic aerosol appears to be formed locally. In addition, 29 aerosol filter samples were analyzed using proton nuclear magnetic resonance (1H NMR) spectroscopy to determine relative concentrations of organic functional groups. Houston aerosols are less oxidized than those observed elsewhere, with smaller relative contributions of carbon-oxygen double bonds. These particles do not fit 1H NMR source apportionment fingerprints for identification of secondary, marine, and biomass burning organic aerosol, suggesting that a new fingerprint for highly urbanized and industrially influenced locations be established.

  18. Quantitative Pulmonary Imaging Using Computed Tomography and Magnetic Resonance Imaging

    Science.gov (United States)

    Washko, George R.; Parraga, Grace; Coxson, Harvey O.

    2011-01-01

    Measurements of lung function, including spirometry and body plethesmography, are easy to perform and are the current clinical standard for assessing disease severity. However, these lung functional techniques do not adequately explain the observed variability in clinical manifestations of disease and offer little insight into the relationship of lung structure and function. Lung imaging and the image based assessment of lung disease has matured to the extent that it is common for clinical, epidemiologic, and genetic investigation to have a component dedicated to image analysis. There are several exciting imaging modalities currently being used for the non-invasive study of lung anatomy and function. In this review we will focus on two of them, x-ray computed tomography and magnetic resonance imaging. Following a brief introduction of each method we detail some of the most recent work being done to characterize smoking-related lung disease and the clinical applications of such knowledge. PMID:22142490

  19. ISEE 3 observations of low-energy proton bidirectional events and their relation to isolated interplanetary magnetic structures

    Science.gov (United States)

    Marsden, R. G.; Sanderson, T. R.; Tranquille, C.; Wenzel, K.-P.; Smith, E. J.

    1987-01-01

    The paper represents the results of a comprehensive survey of low-energy proton bidirectional anisotropies and associated transient magnetic structures as observed in the 35-1600 keV energy range on ISEE-3 during the last solar maximum. The majority of observed bidirectional flow (BDF) events (more than 70 percent) are associated with isolated magnetic structures which are postulated to be an interplanetary manifestation of coronal mass ejection (CME) events. The observed BDF events can be qualitatively grouped into five classes depending on the field signature of the related magnetic structure and the association (or lack of association) with an interplanetary shock. Concerning the topology of the CME-related magnetic structures, the observations are interpreted as being consistent with a detached bubble, comprising closed loops or tightly wound helices.

  20. Development of an all-permanent-magnet microwave ion source equipped with multicusp magnetic fields for high current proton beam production.

    Science.gov (United States)

    Tanaka, M; Hara, S; Seki, T; Iga, T

    2008-02-01

    An all-permanent-magnet (APM) microwave hydrogen ion source was developed to reduce the size and to simplify structure of a conventional solenoid coil microwave ion source developed for reliability improvement of high current proton linac application systems. The difficulty in developing the APM source was sensitive dependence of the source performance on axial magnetic field in the microwave discharge chamber. It was difficult to produce high current proton beam stably without precise tuning of the magnetic field using solenoid coils. We lowered the sensitivity using multicusp magnetic fields for plasma confinement at the discharge chamber sidewall of the source. This enabled stable high current proton beam production with the APM microwave ion source with no tuning coil. The water cooling and the power supply for the coils are not necessary for the APM source, which leads to better reliability and system simplification. The outer diameter of the APM source was around 300 mm, which was 20% lower than the coil source. The APM source produced a maximum hydrogen ion beam current of 65 mA (high current density of 330 mA/cm(2), proton ratio of 87%, and beam energy of 30 keV) with a 5 mm diameter extraction aperture, pulse width of 400 micros, and 20 Hz repetition rate at 1.3 kW microwave power. This performance is almost the same as the best performances of the conventional coil sources. The extracted ion beams were focused with electrostatic five-grid lens to match beam to acceptance of radio-frequency quadrupole linacs. The maximum focused beam current through the orifice (5 mm radius) and the lens was 36 mA and the 90% focused beam half-width was 1-2 mm.

  1. Development of an all-permanent-magnet microwave ion source equipped with multicusp magnetic fields for high current proton beam productiona)

    Science.gov (United States)

    Tanaka, M.; Hara, S.; Seki, T.; Iga, T.

    2008-02-01

    An all-permanent-magnet (APM) microwave hydrogen ion source was developed to reduce the size and to simplify structure of a conventional solenoid coil microwave ion source developed for reliability improvement of high current proton linac application systems. The difficulty in developing the APM source was sensitive dependence of the source performance on axial magnetic field in the microwave discharge chamber. It was difficult to produce high current proton beam stably without precise tuning of the magnetic field using solenoid coils. We lowered the sensitivity using multicusp magnetic fields for plasma confinement at the discharge chamber sidewall of the source. This enabled stable high current proton beam production with the APM microwave ion source with no tuning coil. The water cooling and the power supply for the coils are not necessary for the APM source, which leads to better reliability and system simplification. The outer diameter of the APM source was around 300mm, which was 20% lower than the coil source. The APM source produced a maximum hydrogen ion beam current of 65mA (high current density of 330mA/cm2, proton ratio of 87%, and beam energy of 30keV) with a 5mm diameter extraction aperture, pulse width of 400μs, and 20Hz repetition rate at 1.3kW microwave power. This performance is almost the same as the best performances of the conventional coil sources. The extracted ion beams were focused with electrostatic five-grid lens to match beam to acceptance of radio-frequency quadrupole linacs. The maximum focused beam current through the orifice (5mm radius) and the lens was 36mA and the 90% focused beam half-width was 1-2mm.

  2. The effects of the RHIC E-lenses magnetic structure layout on the proton beam trajectory

    Energy Technology Data Exchange (ETDEWEB)

    Gu, X.; Pikin, A.; Luo, Y.; Okamura, M.; Fischer, W.; Gupta, R.; Hock, J.; Raparia, D.

    2011-03-28

    We are designing two electron lenses (E-lens) to compensate for the large beam-beam tune spread from proton-proton interactions at IP6 and IP8 in the Relativistic Heavy Ion Collider (RHIC). They will be installed in RHIC IR10. First, the layout of these two E-lenses is introduced. Then the effects of e-lenses on proton beam are discussed. For example, the transverse fields of the e-lens bending solenoids and the fringe field of the main solenoids will shift the proton beam. For the effects of the e-lens on proton beam trajectory, we calculate the transverse kicks that the proton beam receives in the electron lens via Opera at first. Then, after incorporating the simplified E-lens lattice in the RHIC lattice, we obtain the closed orbit effect with the Simtrack Code.

  3. A simple method for the identification and assay of iopamidol and iothalamate meglumine in pharmaceutical samples based on proton nuclear magnetic resonance spectroscopy.

    Science.gov (United States)

    Hanna, G M; Lau-Cam, C A

    2001-02-01

    A proton nuclear magnetic resonance (PMR) spectroscopic method is described for the direct assay and identification of the triiodinated radiographic contrast agents iopamidol (nonionic type) and iothalamate meglumine (ionic type) in commercial solutions and as a bulk material. Samples were prepared by simply diluting an injectable solution with or dissolving a powdered sample in D2O. Sodium acetate was added to serve as an internal standard. Quantitations were based on the resonance signals for the protons of the CH3-CO-group at 1.58 ppm (iopamidol) or 2.25 ppm (iothalamate), CH3-N-group at 2.38 ppm (meglumine) and CH3-CO-group at 1.92 ppm (acetate). The mean +/- SD (n = sets of 10 samples each) recovery of iopamidol, iothalamic acid and meglumine from synthetic mixtures with the internal standard were 99.6 +/- 0.63, 99.7 +/- 0.66 and 99.9 +/- 1.18%, respectively; with the values ranging from 98.7-100.9% for iopamidol and iothalamate, and from 98.3-100.8% for meglumine.

  4. Local Quark-Hadron Duality and Magnetic Form Factors of Bound Proton

    Institute of Scientific and Technical Information of China (English)

    WANG Hong-Min; ZHANG Ben-Ai

    2005-01-01

    We discuss the consequence of local duality for elastic scattering, and derive a model-independent equation between structure functions at x ~ 1 and elastic electromagnetic form factors. Then the electromagnetic form factors of proton are discussed using the quark-hadron duality theory. We also debate the form factor of proton in a bound state.It may be an effective approach to study the form factor of proton in media.

  5. Differences between spinocerebellar ataxias and multiple system atrophy-cerebellar type on proton magnetic resonance spectroscopy.

    Directory of Open Access Journals (Sweden)

    Jiing-Feng Lirng

    Full Text Available PURPOSE: A broad spectrum of diseases can manifest cerebellar ataxia. In this study, we investigated whether proton magnetic resonance spectroscopy (MRS may help differentiate spinocerebellar ataxias (SCA from multiple systemic atrophy- cerebellar type (MSA-C. MATERIAL AND METHODS: This prospective study recruited 156 patients with ataxia, including spinocerebellar ataxia (SCA types 1, 2, 3, 6 and 17 (N = 94 and MSA-C (N = 62, and 44 healthy controls. Single voxel proton MRS in the cerebellar hemispheres and vermis were measured. The differences were evaluated using nonparametric statistic tests. RESULTS: When compared with healthy controls, the cerebellar and vermis NAA/Cr and NAA/Cho were lower in all patients(p<0.002. The Cho/Cr was lower in SCA2 and MSA-C (p<0.0005. The NAA/Cr and Cho/Cr were lower in MSA-C or SCA2 comparing with SCA3 or SCA6. The MRS features of SCA1 were in between (p<0.018. The cerebellar NAA/Cho was lower in SCA2 than SCA1, SCA3 or SCA6 (p<0.04. The cerebellar NAA/Cho in MSA-C was lower than SCA3 (p<0.0005. In the early stages of diseases (SARA score<10, significant lower NAA/Cr and NAA/Cho in SCA2, SCA3, SCA6 or MSA-C were observed comparing with healthy controls (p<0.017. The Cho/Cr was lower in MSA-C or SCA2 (p<0.0005. Patients with MSA-C and SCA2 had lower NAA/Cr and Cho/Cr than SCA3 or SCA6 (p<0.016. CONCLUSION: By using MRS, significantly lower NAA/Cr, Cho/Cr and NAA/Cho in the cerebellar hemispheres and vermis were found in patients with ataxia (SCAs and MSA-C. Rapid neuronal degeneration and impairment of membrane activities were observed more often in patients with MSA-C than those with SCA, even in early stages. MRS could also help distinguish between SCA2 and other subtypes of SCAs. MRS ratios may be of use as biomarkers in early stages of disease and should be further assessed in a longitudinal study.

  6. Search for magnetic monopoles with the MoEDAL prototype trapping detector in 8 TeV proton-proton collisions at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Acharya, B. [Theoretical Particle Physics & Cosmology Group, Physics Dept., King’s College London (United Kingdom); International Centre for Theoretical Physics, Trieste (Italy); Alexandre, J. [Theoretical Particle Physics & Cosmology Group, Physics Dept., King’s College London (United Kingdom); Bendtz, K. [Physics Department, Stockholm University, Stockholm (Sweden); Benes, P. [IEAP, Czech Technical University in Prague (Czech Republic); Collaboration: The MoEDAL collaboration; and others

    2016-08-10

    The MoEDAL experiment is designed to search for magnetic monopoles and other highly-ionising particles produced in high-energy collisions at the LHC. The largely passive MoEDAL detector, deployed at Interaction Point 8 on the LHC ring, relies on two dedicated direct detection techniques. The first technique is based on stacks of nuclear-track detectors with surface area ∼18 m{sup 2}, sensitive to particle ionisation exceeding a high threshold. These detectors are analysed offline by optical scanning microscopes. The second technique is based on the trapping of charged particles in an array of roughly 800 kg of aluminium samples. These samples are monitored offline for the presence of trapped magnetic charge at a remote superconducting magnetometer facility. We present here the results of a search for magnetic monopoles using a 160 kg prototype MoEDAL trapping detector exposed to 8 TeV proton-proton collisions at the LHC, for an integrated luminosity of 0.75 fb{sup −1}. No magnetic charge exceeding 0.5g{sub D} (where g{sub D} is the Dirac magnetic charge) is measured in any of the exposed samples, allowing limits to be placed on monopole production in the mass range 100 GeV≤m≤ 3500 GeV. Model-independent cross-section limits are presented in fiducial regions of monopole energy and direction for 1g{sub D}≤|g|≤6g{sub D}, and model-dependent cross-section limits are obtained for Drell-Yan pair production of spin-1/2 and spin-0 monopoles for 1g{sub D}≤|g|≤4g{sub D}. Under the assumption of Drell-Yan cross sections, mass limits are derived for |g|=2g{sub D} and |g|=3g{sub D} for the first time at the LHC, surpassing the results from previous collider experiments.

  7. Assessment of quantitative hypertrophy scores in hypertrophic cardiomyopathy : Magnetic resonance imaging versus echocardiography

    NARCIS (Netherlands)

    Posma, JL; Blanksma, PK; vanderWall, EE; Hamer, HPM; Mooyaart, EL; Lie, KI

    1996-01-01

    To compare the diagnostic value of spin-echo magnetic resonance (MR) imaging and transthoracic echocardiography in quantitative assessment of the extent of hypertrophy in patients with hypertrophic cardiomyopathy (HCM), we examined 52 consecutive patients with HCM. The Spirito-Maron and Wigle hypert

  8. Assessment of quantitative hypertrophy scores in hypertrophic cardiomyopathy : Magnetic resonance imaging versus echocardiography

    NARCIS (Netherlands)

    Posma, JL; Blanksma, PK; vanderWall, EE; Hamer, HPM; Mooyaart, EL; Lie, KI

    1996-01-01

    To compare the diagnostic value of spin-echo magnetic resonance (MR) imaging and transthoracic echocardiography in quantitative assessment of the extent of hypertrophy in patients with hypertrophic cardiomyopathy (HCM), we examined 52 consecutive patients with HCM. The Spirito-Maron and Wigle hypert

  9. Machine learning applied to proton radiography

    CERN Document Server

    Chen, Nicholas Fang Yew; Ceurvorst, Luke; Ratan, Naren; Sadler, James; Levy, Matthew; Trines, Raoul; Bingham, Robert; Norreys, Peter

    2016-01-01

    Proton radiography is a technique extensively used to resolve magnetic field structures in high energy density plasmas, revealing a whole variety of interesting phenomena such as magnetic reconnection and collisionless shocks found in astrophysical systems. Existing methods of analyzing proton radiographs give mostly qualitative results or specific quantitative parameters such as magnetic field strength, and recent work showed that the line-integrated transverse magnetic field can be reconstructed in specific regimes where many simplifying assumptions were needed. Using artificial neural networks, we suggest a novel 3-D reconstruction method that works for a more general case. A proof of concept is presented here, with mean reconstruction errors of less than 5 percent even after introducing noise. We demonstrate that over the long term, this approach is more computationally efficient compared to other techniques. We also highlight the need for proton tomography because (i) certain field structures cannot be r...

  10. Quantitative assessment of renal function with magnetic resonance imaging; Quantitative Erfassung der renalen Funktion mit der Magnetresonanztomographie

    Energy Technology Data Exchange (ETDEWEB)

    Schoenberg, S.O.; Bock, M.; Aumann, S.; Essig, M.; Floemer, F.; Knopp, M.V.; Kaick, G. van [Deutsches Krebsforschungszentrum Heidelberg (Germany). Abt. Radiologische Diagnostik und Therapie; Just, A. [Heidelberg Univ. (Germany). 1. Physiologisches Inst.

    2000-10-01

    Aim. To show the potential of various methods in magnetic resonance imaging for the evaluation of renal function. Material and Methods. A combined assessment of renal morphology, renal hemodynamics and function is proposed. Various techniques are explained, including multiphasic 3D gadolinium MR angiography, MR phase-contrast flow measurements, quantitative perfusion measurements with intravascular contrast agents, and MR renography and MR urography. The use of these techniques is demonstrated for renovascular diseases. Results. The combined use of these techniques allows renal artery stenosis to be accurately detected and evaluation of renal blood flow, perfusion, glomerular filtration rate, and renal excretion. Based on true quantitative parameters, the hemodynamic and functional significance of the stenosis can be assessed. Renovascular diseases can be differentiated from renoparenchymal disease. Conclusion. For the assessment of renal function, functional magnetic resonance imaging techniques are an important alternative to nuclear medicine. The predictive value regarding the effect of revascularization is currently under investigation. (orig.) [German] Fragestellung. Verschiedene Methoden der Magnetresonanztomographie zur quantitativen Erfassung der Nierenfunktion sollen aufgezeigt werden. Methodik. Es werden MR-Techniken zur kombinierten Beurteilung der renalen Morphologie, Haemodynamik und Funktion der Niere vorgestellt. Zur Anwendung kommen hierbei die multiphasische 3-D-Gadolinium-MR-Angiographie, die MR-Phasenkontrastflussmessung, die quantitative Perfusionsmessung mit intravasalen Kontrastmitteln sowie die MR-Renographie/MR-Urographie. Die Methoden werden exemplarisch am Beispiel renovaskulaerer Erkrankungen demonstriert. Ergebnisse. Mit den vorgestellten Methoden lassen sich Nierenarterienstenosen akkurat detektieren sowie Aenderungen des renalen Blutflusses, der Nierenperfusion, der Filtrationsleistung sowie der renalen Ausscheidung erfassen. Auf der

  11. Complete Proton and Carbon Assignment of Triclosan via One- and Two- Dimensional Nuclear Magnetic Resonance Analysis

    Science.gov (United States)

    Students from an upper-division undergraduate spectroscopy class analyzed one- and two-dimensional 400 MHz NMR spectroscopic data from triclosan in CDCl3. Guided assignment of all proton and carbon signals was completed via 1D proton and carbon, nuclear Overhauser effect (nOe), distortionless enhanc...

  12. Quantitative chemical exchange saturation transfer (qCEST) MRI--RF spillover effect-corrected omega plot for simultaneous determination of labile proton fraction ratio and exchange rate.

    Science.gov (United States)

    Sun, Phillip Zhe; Wang, Yu; Dai, ZhuoZhi; Xiao, Gang; Wu, Renhua

    2014-01-01

    Chemical exchange saturation transfer (CEST) MRI is sensitive to dilute proteins and peptides as well as microenvironmental properties. However, the complexity of the CEST MRI effect, which varies with the labile proton content, exchange rate and experimental conditions, underscores the need for developing quantitative CEST (qCEST) analysis. Towards this goal, it has been shown that omega plot is capable of quantifying paramagnetic CEST MRI. However, the use of the omega plot is somewhat limited for diamagnetic CEST (DIACEST) MRI because it is more susceptible to direct radio frequency (RF) saturation (spillover) owing to the relatively small chemical shift. Recently, it has been found that, for dilute DIACEST agents that undergo slow to intermediate chemical exchange, the spillover effect varies little with the labile proton ratio and exchange rate. Therefore, we postulated that the omega plot analysis can be improved if RF spillover effect could be estimated and taken into account. Specifically, simulation showed that both labile proton ratio and exchange rate derived using the spillover effect-corrected omega plot were in good agreement with simulated values. In addition, the modified omega plot was confirmed experimentally, and we showed that the derived labile proton ratio increased linearly with creatine concentration (p exchange rate (p = 0.32). In summary, our study extends the conventional omega plot for quantitative analysis of DIACEST MRI.

  13. A proton nuclear magnetic resonance-based metabonomics study of metabolic profiling in immunoglobulin a nephropathy

    Energy Technology Data Exchange (ETDEWEB)

    Sui, Weiguo; Che, Wenti; Guimai, Zuo; Chen, Jiejing [181st Hospital Guangxi, Central Laboratory, Laboratory of Metabolic Diseases Research, Guangxi Province (China); Li, Liping [Guangxi Normal University, The Life Science College, Guangxi Province (China); Li, Wuxian [Key Laboratory of Laboratory Medical Diagnostics of Education Ministry, Chongqiong Medical University, Chongqing (China); Dai, Yong [Clinical Medical Research Center, the Second Clinical Medical College of Jinan University (Shenzhen People' s Hospital), Shenzhen, Guangdong Province (China)

    2012-07-01

    Objectives: Immunoglobulin A nephropathy is the most common cause of chronic renal failure among primary glomerulonephritis patients. The ability to diagnose immunoglobulin A nephropathy remains poor. However, renal biopsy is an inconvenient, invasive, and painful examination, and no reliable biomarkers have been developed for use in routine patient evaluations. The aims of the present study were to identify immunoglobulin A nephropathy patients, to identify useful biomarkers of immunoglobulin A nephropathy and to establish a human immunoglobulin A nephropathy metabolic profile. Methods: Serum samples were collected from immunoglobulin A nephropathy patients who were not using immunosuppressants. A pilot study was undertaken to determine disease-specific metabolite biomarker profiles in three groups: healthy controls (N = 23), low-risk patients in whom immunoglobulin A nephropathy was confirmed as grades I-II by renal biopsy (N = 23), and high-risk patients with nephropathies of grades IV-V (N = 12). Serum samples were analyzed using proton nuclear magnetic resonance spectroscopy and by applying multivariate pattern recognition analysis for disease classification. Results: Compared with the healthy controls, both the low-risk and high-risk patients had higher levels of phenylalanine, myo-inositol, lactate, L6 lipids ( CH-CH{sub 2}-CH = O), L5 lipids (-CH{sub 2}-C = O), and L3 lipids (-CH{sub 2}-CH{sub 2}-C = O) as well as lower levels of {beta}-glucose, {alpha}-glucose, valine, tyrosine, phosphocholine, lysine, isoleucine, glycerolphosphocholine, glycine, glutamine, glutamate, alanine, acetate, 3-hydroxybutyrate, and 1-methylhistidine. Conclusions: These metabolites investigated in this study may serve as potential biomarkers of immunoglobulin A nephropathy. Point scoring of pattern recognition analysis was able to distinguish immunoglobulin A nephropathy patients from healthy controls. However, there were no obvious differences between the low-risk and high

  14. Localised proton magnetic resonance spectroscopy of the brain after perinatal hypoxia: a preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    Chateil, J.F. [Service de Radiologie A, Hopital Pellegrin, Bordeaux (France)]|[Unite de Radiopediatrie, Hopital Pellegrin, Bordeaux (France); Quesson, B.; Thiaudiere, E.; Delalande, C.; Canioni, P. [Resonance Magnetique des Systemes Biologiques, CNRS, Bordeaux (France); Brun, M.; Diard, F. [Service de Radiologie A, Hopital Pellegrin, Bordeaux (France); Sarlangue, J.; Billeaud, C. [Service de Neonatalogie, Hopital Pellegrin, Bordeaux (France)

    1999-03-01

    Objectives. Perinatal hypoxic ischaemic injury is a significant cause of neurodevelopmental impairment. The aim of this study was to evaluate localised proton magnetic resonance spectroscopy ({sup 1}H-MRS) after birth asphyxia. Materials and methods. Thirty newborn infants suspected of having perinatal asphyxia (Apgar score < 3) were studied. The mean gestational age was 37 weeks, mean age at the MR examination was 18 days and mean weight was 2.9 kg. A 1.5-T unit was used for imaging and spectroscopy. None of the babies had mechanically assisted ventilation. No sedation was used. Axial T1-weighted and T2-weighted images were obtained. {sup 1}H-MRS was recorded in a single voxel, localised in white matter, using a STEAM sequence. Results. Image quality was good in 25 of 30 babies. {sup 1}H-MRS was performed in 19 of 30 subjects, with adequate quality in 16. Choline, creatine/phosphocreatine and N-acetylaspartate peaks and peak-area ratios were analysed. Lactate was detected in four infants. The N-acetylaspartate/choline ratio was lower in infants with an impaired neurological outcome, but the difference was not statistically significant. Conclusions. This study suggests that {sup 1}H-MRS may be useful for assessing cerebral metabolism in the neonate. A raised lactate level and decreased N-acetylaspartate/choline ratio may be predictive of a poor outcome. However, in our experience this method is limited by the difficulty in performing the examination during the first hours after birth in critically ill babies, the problems related to use of a monovoxel sequence, the dispersion of the ratios and the lack of determination of the absolute concentration of the metabolites. (orig.) With 3 figs., 2 tabs., 20 refs.

  15. Proton magnetic resonance spectroscopy and single photon emission CT in patients with olivopontocerebellar atrophy

    Energy Technology Data Exchange (ETDEWEB)

    Ikuta, Naomi [Yamaguchi Univ., Ube (Japan). School of Medicine

    1998-04-01

    Using proton magnetic resonance spectroscopy ({sup 1}H-MRS) and single photon emission CT (SPECT), the cerebellum of patients with olivopontocerebellar atrophy (OPCA) and of age-matched control subjects was studied. A spectrum was collected from a 27 cm{sup 3} (3 x 3 x 3 cm) voxel in the cerebellum containing white and gray matters in order to measure the distribution and relative signal intensities of N-acetylaspartate (NAA), creatine (Cre) and choline (Cho). In the cerebellum of the patients with OPCA, mean NAA/Cre ratios for OPCA patients were significantly decreased compared with normal control subjects (OPCA, 1.01{+-}0.247; controls, 1.526{+-}0.144: p<0.001). Mean NAA/Cho ratios for OPCA patients were slightly decreased (OPCA, 1.285{+-}0.228; controls 1.702{+-}0.469: p<0.06). Cho/Cre ratios valued in the cerebellum of OPCA patients were not significantly different from those in normal controls (OPCA, 0.793{+-}0.186; controls, 0.946{+-}0.219). The ratio of RI count in the cerebellum to that in the occipital lobe was significantly decreased in OPCA patients (OPCA, 0.947{+-}0.096; controls, 1.06{+-}0.063: p<0.01). Cerebellar signs were assessed including gait ataxia, limb ataxia, dysarthria, saccadic pursuit, and nystagmus separately or in combination. In patients with more severe ataxic gait and dysarthria, MRS revealed slightly lowered NAA/Cre ratio. There was no significant correlation between NAA/Cre ratio and severity of other clinical signs. The MRS and SPECT findings give a confirmative evidence of hypofunction in cerebellum of patients with OPCA. (author)

  16. Proton magnetic resonance spectroscopy in patients with early stages of amyotrophic lateral sclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Sivak, Stefan [Comenius University, Clinic of Neurology, Jessenius Faculty of Medicine, Martin (Slovakia); Jessenius Medical Faculty, Clinic of Neurology, Martin (Slovakia); Bittsansky, Michal; Dobrota, Dusan [Comenius University, Department of Medical Biochemistry, Jessenius Faculty of Medicine, Martin (Slovakia); Kurca, Egon; Turcanova-Koprusakova, Monika; Grofik, Milan; Nosal, Vladimir [Comenius University, Clinic of Neurology, Jessenius Faculty of Medicine, Martin (Slovakia); Polacek, Hubert [Comenius University, Clinic of Radiodiagnostics, Jessenius Faculty of Medicine, Martin (Slovakia)

    2010-12-15

    Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder primarily affecting upper and lower motor neurons. Due to relative fast progression of the disease, early diagnosis is essential. Proton magnetic resonance spectroscopy ({sup 1}H-MRS) is used for objectivization of upper motor neuron (UMN) lesions. The aim of this study was to assess the use of {sup 1}H-MRS in the early stages of ALS. Eleven patients with clinically definite (n = 2), probable (n = 7), and probable laboratory-supported (n = 2) diagnosis of ALS with disease duration of less than 14 months were studied. Control group consists of 11 sex- and age-matched healthy subjects. All subjects underwent assessment of functional disability using revised ALS Functional Rating Scale (ALSFRS-R) and single-voxel {sup 1}H-MRS examination of both precentral gyri, pons, medulla oblongata, and occipital lobe. Spectra were evaluated with LCModel software. The mean disease duration was 6.5 {+-} 3.5 months. The median ALSFRS-R was 42. Significant decrease between patient and control groups was found in the NAA/Cre ratio in the left and right precentral gyri (p = 0.008, p = 0.040). Other metabolite ratios in other areas did not show significant differences. Total ALSFRS-R score weakly positively correlated with NAA/Cre ratio in the left precentral gyrus (p = 0.047). {sup 1}H-MRS is sensitive to detect metabolic changes caused by neurodegeneration processes during ALS and can be used for detection of UMN dysfunction. These MRS changes in the early stages of ALS are most prominent in motor cortex. (orig.)

  17. Individual variation in macronutrient regulation measured by proton magnetic resonance spectroscopy of human plasma.

    Science.gov (United States)

    Park, Youngja; Kim, Seoung Bum; Wang, Bing; Blanco, Roberto A; Le, Ngoc-Anh; Wu, Shaoxiong; Accardi, Carolyn J; Alexander, R Wayne; Ziegler, Thomas R; Jones, Dean P

    2009-07-01

    Proton nuclear magnetic resonance ((1)H-NMR) spectroscopy of plasma provides a global metabolic profiling method that shows promise for clinical diagnostics. However, cross-sectional studies are complicated by a lack of understanding of intraindividual variation, and this limits experimental design and interpretation of data. The present study determined the diurnal variation detected by (1)H NMR spectroscopy of human plasma. Data reduction methods revealed three time-of-day metabolic patterns, which were associated with morning, afternoon, and night. Major discriminatory regions for these time-of-day patterns included the various kinds of lipid signals (-CH(2)- and -CH(2)OCOR), and the region between 3 and 4 ppm heavily overlapped with amino acids that had alpha-CH and alpha-CH(2). The phasing and duration of time-of-day patterns were variable among individuals, apparently because of individual difference in food processing/digestion and absorption and clearance of macronutrient energy sources (fat, protein, carbohydrate). The times of day that were most consistent among individuals, and therefore most useful for cross-sectional studies, were fasting morning (0830-0930), postprandial afternoon (1430-1630), and nighttime samples (0430-0530). Importantly, the integrated picture of metabolism provided by (1)H-NMR spectroscopy of plasma suggests that this approach is suitable to study complex regulatory processes, including eating patterns/eating disorders, upper gastrointestinal functions (gastric emptying, pancreatic, biliary functions), and absorption/clearance of macronutrients. Hence, (1)H-NMR spectroscopy of plasma could provide a global metabolic tolerance test to assess complex processes involved in disease, including eating disorders and the range of physiological processes causing dysregulation of energy homeostasis.

  18. Thermodynamics of wheat germ agglutinin-sialyloligosaccharide interactions by proton nuclear magnetic resonance.

    Science.gov (United States)

    Kronis, K A; Carver, J P

    1985-02-12

    The thermodynamic parameters that characterize the binding of wheat germ agglutinin isolectin I (WGA I) to the alpha 2-3 isomer of (N-acetylneuraminyl)lactose have been determined by 360-MHz proton nuclear magnetic resonance spectroscopy. The chemical exchange of the ligand between the free and bound sites resulted in a broadening and upfield shifting of the N-acetyl methyl resonance [Kronis, K.A., & Carver, J.P. (1985) Biochemistry (preceding paper in this issue)] which has allowed the determination of the equilibrium constant, KD, and the dissociation rate constant, kD. In this paper, the analysis of the temperature dependence of the KD values between 25.4 and 51.6 degrees C yielded equilibrium parameters indicative of a large entropy barrier to binding: delta H degree = -13.3 +/- 1.0 kcal mol-1 and delta S degree = -31.9 +/- 2.4 cal mol-1 K-1. The Arrhenius plot of the effect of temperature on the dissociation rate (kD) and the plot of 1n (kD/T) vs. 1/T indicated that the transition complex represented an unfavorable energy state compared to the dissociated molecules with an activation energy (EA) of +18.0 kcal mol-1 and enthalpy and entropy of dissociation (delta HD not equal to and delta SD not equal to) values of +17.4 +/- 0.3 kcal mol-1 and +13.4 +/- 1.2 cal mol-1 K-1, respectively. The driving force for this binding reaction is the large negative delta H degree with a small enthalpic barrier to association (delta HA = +4.1 kcal mol-1).(ABSTRACT TRUNCATED AT 250 WORDS)

  19. A proton nuclear magnetic resonance-based metabonomics study of metabolic profiling in immunoglobulin a nephropathy

    Directory of Open Access Journals (Sweden)

    Weiguo Sui

    2012-01-01

    Full Text Available OBJECTIVES: Immunoglobulin A nephropathy is the most common cause of chronic renal failure among primary glomerulonephritis patients. The ability to diagnose immunoglobulin A nephropathy remains poor. However, renal biopsy is an inconvenient, invasive, and painful examination, and no reliable biomarkers have been developed for use in routine patient evaluations. The aims of the present study were to identify immunoglobulin A nephropathy patients, to identify useful biomarkers of immunoglobulin A nephropathy and to establish a human immunoglobulin A nephropathy metabolic profile. METHODS: Serum samples were collected from immunoglobulin A nephropathy patients who were not using immunosuppressants. A pilot study was undertaken to determine disease-specific metabolite biomarker profiles in three groups: healthy controls (N = 23, low-risk patients in whom immunoglobulin A nephropathy was confirmed as grades I-II by renal biopsy (N = 23, and high-risk patients with nephropathies of grades IV-V (N = 12. Serum samples were analyzed using proton nuclear magnetic resonance spectroscopy and by applying multivariate pattern recognition analysis for disease classification. RESULTS: Compared with the healthy controls, both the low-risk and high-risk patients had higher levels of phenylalanine, myo-Inositol, lactate, L6 lipids ( = CH-CH2-CH = O, L5 lipids (-CH2-C = O, and L3 lipids (-CH2-CH2-C = O as well as lower levels of β -glucose, α-glucose, valine, tyrosine, phosphocholine, lysine, isoleucine, glycerolphosphocholine, glycine, glutamine, glutamate, alanine, acetate, 3-hydroxybutyrate, and 1-methylhistidine. CONCLUSIONS: These metabolites investigated in this study may serve as potential biomarkers of immunoglobulin A nephropathy. Point scoring of pattern recognition analysis was able to distinguish immunoglobulin A nephropathy patients from healthy controls. However, there were no obvious differences between the low-risk and high-risk groups in our

  20. Enhancement of proton acceleration by a right-handed circularly polarized laser interaction with a cone target exposed to a longitudinal magnetic field

    Science.gov (United States)

    Gong, J. X.; Cao, L. H.; Pan, K. Q.; Xiao, K. D.; Wu, D.; Zheng, C. Y.; Liu, Z. J.; He, X. T.

    2017-05-01

    Our previous research [J. X. Gong et al. Phys. Plasmas 24, 033103 (2017)] shows that in the presence of an external longitudinal magnetic field, there is no cut-off density when a right-handed (RH-) circularly polarized (CP) laser propagates in the plasmas. In this work, the proton acceleration driven by an RH-CP laser interaction with a pre-magnetized cone target filled with a pre-formed plasma is investigated under the mechanism of target normal sheath acceleration. The strength of the external magnetic field considered in this paper is comparable to that of the incident laser. The two-dimensional particle-in-cell simulation results show that with an external longitudinal magnetic field, both the energy and yield of protons accelerated by the sheath electric field at the rear of the target are remarkably increased because of the higher coupling efficiency from RH-CP laser energy to electrons and the more efficient electron acceleration. Electrons can be converged remarkably by the external magnetic field and the divergence of protons can be controlled evidently by the collimated electrons. The maximum cut-off energy of protons with an imposed longitudinal magnetic field can be promoted to be as high as 82 MeV. Detailed simulation results show that the maximum energy of protons increases with the increasing initial external magnetic field.

  1. Proton magnetic resonance spectroscopy of the motor cortex in cervical myelopathy.

    Science.gov (United States)

    Kowalczyk, Izabela; Duggal, Neil; Bartha, Robert

    2012-02-01

    Alterations in motor function in cervical myelopathy secondary to degenerative disease may be due to local effects of spinal compression or distal effects related to cortical reorganization. This prospective study characterizes differences in metabolite levels in the motor cortex, specifically N-acetylaspartate, creatine, choline, myo-inositol and glutamate plus glutamine, due to alterations in cortical function in patients with reversible spinal cord compression compared with healthy controls. We hypothesized that N-acetylaspartate/creatine levels would be decreased in the motor cortex of patients with cervical myelopathy due to reduced neuronal integrity/function and myo-inositol/creatine levels would be increased due to reactive gliosis. Twenty-four patients with cervical myelopathy and 11 healthy controls underwent proton-magnetic resonance spectroscopy on a 3.0 Tesla Siemens Magnetom Tim Trio MRI. Areas of activation from functional magnetic resonance imaging scans of a finger-tapping paradigm were used to localize a voxel on the side of greater motor deficit in the myelopathy group (n = 10 on right side and n = 14 on left side of the brain) and on each side of the motor cortex in controls. Neurological function was measured with the Neck Disability Index, modified Japanese Orthopaedic Association and American Spinal Injury Association questionnaires. Metabolite levels were measured relative to total creatine within the voxel of interest. No metabolite differences were detected between the right side and left side of the motor cortex in controls. The myelopathy group had significantly decreased neurological function compared with the control group (Neck Disability Index: P motor cortex of the myelopathy group (1.21 ± 0.07) compared with the right (1.37 ± 0.03; P = 0.01) and left (1.38 ± 0.03; P = 0.007) motor cortex in controls suggesting neuronal damage or dysfunction distal to the lesion in the spine. No difference was

  2. Magnetic structure of geometrically frustrated compound Co{sub 2}Cl(OH){sub 3} determined by proton NMR

    Energy Technology Data Exchange (ETDEWEB)

    Zenmyo, Kazuko [Fukuoka Institute of Technology, Wajirohigashi, Fukuoka 811-0295 (Japan)], E-mail: zenmyou@fit.ac.jp; Tokita, Masahiko [Fukuoka Institute of Technology, Wajirohigashi, Fukuoka 811-0295 (Japan)], E-mail: tokita@fit.ac.jp

    2009-07-15

    The magnetic structure of a geometrically frustrated system Co{sub 2}Cl(OH){sub 3} is determined by comparing the observed proton NMR spectrum with numerical calculations based on various magnetic models. The best fit is obtained with a model that the magnetic moments of Co{sup 2+} ions in the triangular plane are parallel to the principal axis of local crystal field and those of Co{sup 2+} ions in the kagome lattice plane are randomly disordered in the a-b plane, which nearly bisects the angle between the principal axis of the local field and a line pointing towards the body center of the tetrahedron. The coexistence of the ferromagnetic order in the triangular plane and the random disorder in the kagome plane is consistent with the results of measurements by Zheng et al. However, the magnetic moments of Co{sup 2+} ions are not directed towards the body center of the tetrahedron as characteristic in the 'spin ice' magnetic structure. Furthermore, the Co{sup 2+} ions in the triangular plane have a smaller magnitude of magnetic moment than those in the kagome plane. Thus, our result suggests that the transition metal compound Co{sub 2}Cl(OH){sub 3} is different from the 'spin ice' in magnetic structure, although it is similar to rare-earth pyrochlores in crystal structure.

  3. Calculations of influence of electric field on proton magnetic shielding in molecule, by means of Gell-Mann-Feynman theorem

    Energy Technology Data Exchange (ETDEWEB)

    Volodicheva, M.I.; Rebane, T.K.

    1986-01-01

    A method is proposed for calculating the electric-field-linear contribution to the processional magnetic shielding of the nucleus, based on application on the Gell-Mann-Feyman theorem, using the Pade approximant. Calculational formulas have been derived for the first derivatives of the precessional magnetic shielding of the nucleus with respect to the electric field strength, these formulas containing either experimentally determinable characteristics of the molecules or characteristics obtained by interpolation of the observed properties of isoelectronic molecules. No calculations of wavefunctions are required. For hydrogen and hydrogen halide molecules, values have been calculated for the derivatives, with respect to electric field strength, of the precessional sigma/sub H//sup (1)/ prec and total sigma/sub H//sup (1)/ proton magnetic shielding. The results are in good agreement with experimental data.

  4. Protons and electrons in Jupiter's magnetic field - Results from the University of Chicago experiment on Pioneer 10

    Science.gov (United States)

    Simpson, J. A.; Hamilton, D.; Lentz, G.; Mckibben, R. B.; Mogro-Campero, A.; Perkins, M.; Pyle, K. R.; Tuzzolino, A. J.; O'Gallagher, J. J.

    1974-01-01

    Fluxes of high energy electrons and protons are found to be highly concentrated near the magnetic equatorial plane from distances of about 30 to about 100 Jovian radii. The 10-hour period of planetary rotation is observed as an intensity variation, which indicates that the equatorial zone of high particle fluxes is inclined with respect to the rotation axis of the planet. At radial distances below 20 Jovian radii, the synchrotron-radiation-producing electrons with energies above 3 MeV rise steeply to a maximum intensity near the periapsis at 2.8 Jovian radii. The flux of protons with energies above 30 MeV reaches a maximum intensity at 3.5 Jovian radii, with the intensity decreasing inside this radial distance.

  5. A carbon-13 and proton nuclear magnetic resonance study of some experimental referee broadened-specification /ERBS/ turbine fuels

    Science.gov (United States)

    Dalling, D. K.; Pugmire, R. J.

    1982-01-01

    Preliminary results of a nuclear magnetic resonance (NMR) spectroscopy study of alternative jet fuels are presented. A referee broadened-specification (ERBS) aviation turbine fuel, a mixture of 65 percent traditional kerosene with 35 percent hydrotreated catalytic gas oil (HCGO) containing 12.8 percent hydrogen, and fuels of lower hydrogen content created by blending the latter with a mixture of HCGO and xylene bottoms were studied. The various samples were examined by carbon-13 and proton NMR at high field strength, and the resulting spectra are shown. In the proton spectrum of the 12.8 percent hydrogen fuel, no prominent single species is seen while for the blending stock, many individual lines are apparent. The ERBS fuels were fractionated by high-performance liquid chromatography and the resulting fractions analyzed by NMR. The species found are identified.

  6. Effects of proton irradiation on the magnetic properties of GaGdN and GaCrN

    Energy Technology Data Exchange (ETDEWEB)

    Hite, J K; Allums, K K; Thaler, G T; Abernathy, C R; Pearton, S J [Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611 (United States); Frazier, R M [Naval Research Laboratory, WA, DC 20375 (United States); Dwivedi, R; Wilkins, R [Center for Applied Radiation Research, Prairie View A and M University, Prairie View, TX 77446 (United States); Zavada, J M [US Army Research Office, Research Triangle Park, NC 27709 (United States)], E-mail: spear@mse.ufl.edu

    2008-05-15

    GaGdN and GaCrN films grown by gas source molecular beam epitaxy were irradiated with high energy (10 and 40 MeV) protons at a fluence of 5 x 10{sup 9} cm{sup -2} to examine the effect on magnetization. This dose is equivalent to the exposure expected in 10 years in low-earth orbit space missions. Both photoluminescence intensity and magnetization of the films showed significant decreases with irradiation. The largest response was observed with GaGdN, which experienced a 50-60% loss in band edge luminescence and 11-83% loss in magnetic saturation. After annealing the irradiated samples at 500 {sup 0} C under a nitrogen plasma ambient, both types of films experienced a complete recovery in magnetic properties. The fact that the introduction of point defects did not increase the magnetization is evidence against unpaired bonds from defects in the film being responsible for the magnetic properties in the films.

  7. An optimized framework for quantitative magnetization transfer imaging of the cervical spinal cord in vivo.

    Science.gov (United States)

    Battiston, Marco; Grussu, Francesco; Ianus, Andrada; Schneider, Torben; Prados, Ferran; Fairney, James; Ourselin, Sebastien; Alexander, Daniel C; Cercignani, Mara; Gandini Wheeler-Kingshott, Claudia A M; Samson, Rebecca S

    2017-09-16

    To develop a framework to fully characterize quantitative magnetization transfer indices in the human cervical cord in vivo within a clinically feasible time. A dedicated spinal cord imaging protocol for quantitative magnetization transfer was developed using a reduced field-of-view approach with echo planar imaging (EPI) readout. Sequence parameters were optimized based in the Cramer-Rao-lower bound. Quantitative model parameters (i.e., bound pool fraction, free and bound pool transverse relaxation times [ T2F, T2B], and forward exchange rate [kFB ]) were estimated implementing a numerical model capable of dealing with the novelties of the sequence adopted. The framework was tested on five healthy subjects. Cramer-Rao-lower bound minimization produces optimal sampling schemes without requiring the establishment of a steady-state MT effect. The proposed framework allows quantitative voxel-wise estimation of model parameters at the resolution typically used for spinal cord imaging (i.e. 0.75 × 0.75 × 5 mm(3) ), with a protocol duration of ∼35 min. Quantitative magnetization transfer parametric maps agree with literature values. Whole-cord mean values are: bound pool fraction = 0.11(±0.01), T2F = 46.5(±1.6) ms, T2B = 11.0(±0.2) µs, and kFB  = 1.95(±0.06) Hz. Protocol optimization has a beneficial effect on reproducibility, especially for T2B and kFB . The framework developed enables robust characterization of spinal cord microstructure in vivo using qMT. Magn Reson Med, 2017. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of

  8. Ion escape from the high latitude magnetopause: analysis of oxygen and proton dynamics in the presence of magnetic turbulence

    Directory of Open Access Journals (Sweden)

    A. Taktakishvili

    2007-08-01

    Full Text Available Recent Cluster observations of the vicinity of the high latitude magnetopause indicate the presence of beams of singly charged oxygen ions, which are of ionospheric origin. In this paper we examine the role of magnetic turbulence combined with a dc electric field across the magnetopause in causing the cross field transport of protons and of singly charged oxygen ions, by means of a kinetic test particle simulation. We find that the observed values of magnetosheath turbulence and electric fields can produce a substantial escape of the oxygen ions relative to protons. By varying the magnetic turbulence level in the simulation, we find that the number of O+ crossing the magnetopause grows with δB/B0, and that very few ions can cross the magnetopause for δB/B0=0. The ion temperature also grows with δB/B0, showing that magnetic turbulence is effective in thermalizing the kinetic energy gain due to the cross-magnetopause potential drop. We suggest that this mechanism can help to explain Cluster observations of energetic oxygen ions during a high-latitude magnetopause crossing.

  9. Proton magnetic resonance imaging for assessment of lung function and respiratory dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Eichinger, Monika [Deutsches Krebsforschungszentrum (DKFZ), Department of Radiology (E010), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)], E-mail: m.eichinger@dkfz.de; Tetzlaff, Ralf; Puderbach, Michael [Deutsches Krebsforschungszentrum (DKFZ), Department of Radiology (E010), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Woodhouse, Neil [Unit of Academic Radiology, University of Sheffield (United Kingdom); Kauczor, H.-U. [Deutsches Krebsforschungszentrum (DKFZ), Department of Radiology (E010), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)

    2007-12-15

    Since many pulmonary diseases present with a variable regional involvement, modalities for assessment of regional lung function gained increasing attention over the last years. Together with lung perfusion and gas exchange, ventilation, as a result of the interaction of the respiratory pump and the lungs, is an indispensable component of lung function. So far, this complex mechanism is still mainly assessed indirectly and globally. A differentiation between the individual determining factors of ventilation would be crucial for precise diagnostics and adequate treatment. By dynamic imaging of the respiratory pump, the mechanical components of ventilation can be assessed regionally. Amongst imaging modalities applicable to this topic, magnetic resonance imaging (MRI), as a tool not relying on ionising radiation, is the most attractive. Recent advances in MRI technology have made it possible to assess diaphragmatic and chest wall motion, static and dynamic lung volumes, as well as regional lung function. Even though existing studies show large heterogeneity in design and applied methods, it becomes evident that MRI is capable to visualise pulmonary function as well as diaphragmatic and thoracic wall movement, providing new insights into lung physiology. Partly contradictory results and conclusions are most likely caused by technical limitations, limited number of studies and small sample size. Existing studies mainly evaluate possible imaging techniques and concentrate on normal physiology. The few studies in patients with lung cancer and emphysema already give a promising outlook for these techniques from which an increasing impact on improved and quantitative disease characterization as well as better patient management can be expected.

  10. Three-Dimensional Magnetohydrodynamic Modeling of the Solar Wind Including Pickup Protons and Turbulence Transport

    Science.gov (United States)

    Usmanov, Arcadi V.; Goldstein, Melvyn L.; Matthaeus, William H.

    2012-01-01

    To study the effects of interstellar pickup protons and turbulence on the structure and dynamics of the solar wind, we have developed a fully three-dimensional magnetohydrodynamic solar wind model that treats interstellar pickup protons as a separate fluid and incorporates the transport of turbulence and turbulent heating. The governing system of equations combines the mean-field equations for the solar wind plasma, magnetic field, and pickup protons and the turbulence transport equations for the turbulent energy, normalized cross-helicity, and correlation length. The model equations account for photoionization of interstellar hydrogen atoms and their charge exchange with solar wind protons, energy transfer from pickup protons to solar wind protons, and plasma heating by turbulent dissipation. Separate mass and energy equations are used for the solar wind and pickup protons, though a single momentum equation is employed under the assumption that the pickup protons are comoving with the solar wind protons.We compute the global structure of the solar wind plasma, magnetic field, and turbulence in the region from 0.3 to 100 AU for a source magnetic dipole on the Sun tilted by 0 deg - .90 deg and compare our results with Voyager 2 observations. The results computed with and without pickup protons are superposed to evaluate quantitatively the deceleration and heating effects of pickup protons, the overall compression of the magnetic field in the outer heliosphere caused by deceleration, and the weakening of corotating interaction regions by the thermal pressure of pickup protons.

  11. Monitoring of organic contaminants in sediments using low field proton nuclear magnetic resonance

    Science.gov (United States)

    Zhang, Chi; Rupert, Yuri

    2016-04-01

    The effective monitoring of soils and groundwater contaminated with organic compounds is an important goal of many environmental restoration efforts. Recent geophysical methods such as electrical resistivity, complex conductivity, and ground penetrating radar have been successfully applied to characterize organic contaminants in the subsurface and to monitor remediation process both in laboratory and in field. Low field proton nuclear magnetic resonance (NMR) is a geophysical tool sensitive to the molecular-scale physical and chemical environment of hydrogen-bearing fluids in geological materials and shows promise as a novel method for monitoring contaminant remediation. This laboratory research focuses on measurements on synthetic samples to determine the sensitivity of NMR to the presence of organic contaminants and improve understanding of relationships between NMR observables, hydrological properties of the sediments, and amount and state of contaminants in porous media. Toluene, a light non-aqueous phase liquid (LNAPL) has been selected as a representative organic contaminant. Three types of porous media (pure silica sands, montmorillonite clay, and various sand-clay mixtures with different sand/clay ratios) were prepared as synthetic sediments. NMR relaxation time (T2) and diffusion-relaxation (D - T2) correlation measurements were performed in each sediment saturated with water and toluene mixed fluid at assorted concentrations (0% toluene and 100% water, 1% toluene and 99% water, 5% toluene and 95% water, 25% toluene and 75% water, and 100% toluene and 0% water) to 1) understand the effect of different porous media on the NMR responses in each fluid mixture, 2) investigate the role of clay content on T2 relaxation of each fluid, 3) quantify the amount hydrocarbons in the presence of water in each sediment, and 4) resolve hydrocarbons from water in D - T2 map. Relationships between the compositions of porous media, hydrocarbon concentration, and hydraulic

  12. Effects of the interaction between the magnetic moments of the proton and electron on the energy states of hydrogen atom

    CERN Document Server

    Dolocan, Voicu

    2014-01-01

    We make a comparison between the energy levels of the hydrogen atom, calculated by using standard methods, and that by using a modified Coulomb potential due to the interaction between the magnetic moments of the proton and electron. In this later method we use to ways. One is that in which we solve the Schroedinger equation with the modified Coulomb potential and some constraint conditions. The other is that in which we expand the modified Coulomb potential in Taylor series. The obtained results show that the first way gives a better agreement with experimental data.

  13. Learning geosciences from science fictions movies: A quantitative analysis of Pando-magnetism in Avatar.

    Science.gov (United States)

    Martin-Hernandez, F.; Negredo, A. M.; Salguero, J. M.

    2015-12-01

    Many storylines presenting a geoscientific background are portrayed in science fiction movies. However, this background is often discussed only in qualitative terms in outreach books and forums. Here we report a mentoring experience of an end of degree project carried out in the fourth year of the degree in Physics in the Complutense University of Madrid (Spain). The supervisors intended to take advantage of the students' passion for science fiction movies to foster learning by assessing a robust, quantitative and critical analysis of the main geoscientific phenomena appearing in Avatar movie by James Cameron (2009). The student was supposed to consult abundant scientific literature. Much interest was paid to analyze the conditions for the levitation of Hallelujah floating mountains in Pandora, the imaginary satellite where the movie action takes place. Pandora was assumed to be an Earth-like astronomical object where the same physical laws as in the Earth could be applied. Hallelujah Mountains are made of unobtanium, an electrical superconductor at room-temperature and therefore diamagnetic material and they are assumed to be located over a magnetic field pole. The numerical values of the magnetic susceptibility and the required field to make the material levitate at the Pandora's gravity conditions were estimated. For this purpose, the magnetic susceptibility of the superconductor with the highest critical temperature existing today on Earth, the cuprate YBa2Cu3O7 was estimated. Results were compared with the magnetic susceptibility of two diamagnetic and abundant materials in the Earth's crust, namely quartz and calcite, and with the water susceptibility. The magnetic field required to levitate cuprates was almost 9 T, about six orders of magnitude higher than the Earth's magnetic field. On the basis of the quantitative analysis of magnetic and gravity field in Pandora, the student provided a list of suggestions to improve the scientific basis for futures

  14. Quantitative magnetic resonance imaging of the fetal brain in utero: Methods and applications

    Institute of Scientific and Technical Information of China (English)

    Anat; Biegon; Chen; Hoffmann

    2014-01-01

    Application of modern magnetic resonance imaging(MRI) techniques to the live fetus in utero is a relatively recent endeavor. The relative advantages and disadvantages of clinical MRI relative to the widely used and accepted ultrasonographic approach are the subject of a continuing debate; however the focus of this review is on the even younger field of quantitative MRI as applied to non-invasive studies of fetal brain development. The techniques covered under this header include structural MRI when followed by quan-titative(e.g., volumetric) analysis, as well as quantita-tive analyses of diffusion weighted imaging, diffusion tensor imaging, magnetic resonance spectroscopy and functional MRI. The majority of the published work re-viewed here reflects information gathered from normal fetuses scanned during the 3rd trimester, with relatively smaller number of studies of pathological samples including common congenital pathologies such as ven-triculomegaly and viral infection.

  15. Major Metabolite Levels of Preoperative Proton Magnetic Resonance Sectroscopy and Intraoperative Fluorescence Intensity in Glioblastoma.

    Science.gov (United States)

    Tian, Hai-Long; Zu, Yu-Liang; Wang, Chao-Chao; Lin, Tao; Guo, Zhen-Tao; Jiang, Bin; Yin, Xin; Guo, Wen-Qiang; Wang, Zhi-Gang

    2017-08-20

    Objective To compare the intraoperative major metabolite level of preoperative proton magnetic resonance spectroscopy((1)H-MRS)and fluorescence intensity marked with fluorescein sodium(FLs)in glioblastoma(GBM)and thus provide an objective basis for fluorescence surgical treatment of GBM. Methods All newly diagnosed patients by plain and enhanced magnetic resonance imaging from the April 1,2014 to December 31,2015 were enrolled in this study.All of them received (1)H-MRS and marked with FLs.The expression of Ki67 in tumor boundary were confirmed by postoperative pathology and determined by immunostaining assay.The relationship between (1)H-MRS metabolite levels and tumor fluorescence intensity was analyzed. Results Totally 33 patients were included in the study.Preoperative (1)H-MRS revealed high-grade gliomas in 25 cases.The N-acetylaspartate(NAA)decreased significantly and choline(Cho)increased significantly in high-grade gliomas.The ratios of Cho/NAA,NAA/creatine(Cr),and Cho/Cr significantly differed in different tumor regions(P=0.02,P=0.01,and P=0.00,respectively).Surgical results were marked with FLs intraoperatively.Tissue fluorescence were clearly seen.There were 29 patients undergoing total resection and 4 cases undergoing subtotal resection.No acute encephalocele occured after operation,while 2 patients suffered from epilepsy.Postoperative pathology results included:28 cases were diagnosed as GBM(22 cases consistent with (1)H-MRS diagnosis).The results of GBM fluorescence imaging included:the level of fluorescence intensity in tumor parenchyma was significantly higher than that in tumor boundary and peritumoral edema(P=0.01).The result of (1)H-MRS metabolite analysis included:The kurtosis of NAA and of Cho and the ratio of Cho/NAA were significantly different according the fluorescence intensity in tumor parenchyma(P=0.01,P=0.02,and P=0.01).While there was no difference in the kurtosis of NAA,the kurtosis of Cho and the ratio of Cho/NAA were significantly

  16. Simultaneous experimental determination of labile proton fraction ratio and exchange rate with irradiation radio frequency power-dependent quantitative CEST MRI analysis.

    Science.gov (United States)

    Sun, Phillip Zhe; Wang, Yu; Xiao, Gang; Wu, Renhua

    2013-01-01

    Chemical exchange saturation transfer (CEST) imaging is sensitive to dilute proteins/peptides and microenvironmental properties, and has been increasingly evaluated for molecular imaging and in vivo applications. However, the experimentally measured CEST effect depends on the CEST agent concentration, exchange rate and relaxation time. In addition, there may be non-negligible direct radio-frequency (RF) saturation effects, particularly severe for diamagnetic CEST (DIACEST) agents owing to their relatively small chemical shift difference from that of the bulk water resonance. As such, the commonly used asymmetry analysis only provides CEST-weighted information. Recently, it has been shown with numerical simulation that both labile proton concentration and exchange rate can be determined by evaluating the RF power dependence of DIACEST effect. To validate the simulation results, we prepared and imaged two CEST phantoms: a pH phantom of serially titrated pH at a fixed creatine concentration and a concentration phantom of serially varied creatine concentration titrated to the same pH, and solved the labile proton fraction ratio and exchange rate per-pixel. For the concentration phantom, we showed that the labile proton fraction ratio is proportional to the CEST agent concentration with negligible change in the exchange rate. Additionally, we found the exchange rate of the pH phantom is dominantly base-catalyzed with little difference in the labile proton fraction ratio. In summary, our study demonstrated quantitative DIACEST MRI, which remains promising to augment the conventional CEST-weighted MRI analysis.

  17. Protons and Electrons in Jupiter's Magnetic Field: Results from the University of Chicago Experiment on Pioneer 10.

    Science.gov (United States)

    Simpson, J A; Hamilton, D; Lentz, G; McKibben, R B; Mogro-Campero, A; Perkins, M; Pyle, K R; Tuzzolino, A J; O'gallagher, J J

    1974-01-25

    Fluxes of high energy electrons and protons are found to be highly concentrated near the magnetic equatorial plane from distances of ~ 30 to ~ 100 Jovian radii (R(J)). The 10-hour period of planetary rotation is observed as an intensity variation, which indicates that the equatorial zone of high particle fluxes is inclined with respect to the rotation axis of the planet. At radial distances [unknown] 20 R(J) the synchrotron-radiation-producing electrons with energies greater, similar 3 million electron volts rise steeply to a maximum intensity of ~ 5 x 10(8) electrons per square centimeter per second near the periapsis at 2.8 R(J). The flux of protons with energies greater, similar 30 million electron volts reaches a maximum intensity of ~ 4 x 10(6) protons per square centimeter per second at ~ 3.5 R(J) with the intensity decreasing inside this radial distance. Only for radial distances [unknown] 20 R(J) does the radiation behave in a manner which is similar to that at the earth. Burst of electrons with energies up to 30 million electron volts, each lasting about 2 days, were observed in interplanetary space beginning approximately 1 month before encounter. This radiation appears to have escaped from the Jovian bow shock or magnetosphere.

  18. Multinuclear solid state nuclear magnetic resonance investigation of water penetration in proton exchange membrane Nafion-117 by mechanical spinning.

    Science.gov (United States)

    Sabarinathan, Venkatachalam; Wu, Zhen; Cheng, Ren-Hao; Ding, Shangwu

    2013-05-30

    (1)H, (17)O, and (19)F solid state NMR spectroscopies have been used to investigate water penetration in Nafion-117 under mechanical spinning. It is found that both (1)H and (17)O spectra depend on the orientation of the membrane with respect to the magnetic field. The intensities of the side chain (19)F spectra depend slightly on the orientation of membrane with respect to the magnetic field, but the backbone (19)F spectra do not exhibit orientation dependence. By analyzing the orientation dependent (1)H and (17)O spectra and time-resolved (1)H spectra, we show that the water loaded in Nafion-117, under high spinning speed, may penetrate into regions that are normally inaccessible by water. Water penetration is enhanced as the spinning speed is increased or the spinning time is increased. In the meantime, mechanical spinning accelerates water exchange. It is also found that water penetration by mechanical spinning is persistent; i.e., after spinning, water remains in those newly found regions. While water penetration changes the pores and channels in Nafion, (19)F spectra indicate that the chemical environments of the polymer backbone do not show change. These results provide new insights about the structure and dynamics of Nafion-117 and related materials. They are relevant to proton exchange membrane aging and offer enlightening points of view on antiaging and modification of this material for better proton conductivity. It is also interesting to view this phenomenon in the perspective of forced nanofiltration.

  19. Magnetic Resonance Water Proton Relaxation in Protein Solutions and Tissue: T1ρ Dispersion Characterization

    Science.gov (United States)

    Chen, Enn-Ling; Kim, Raymond J.

    2010-01-01

    Background Image contrast in clinical MRI is often determined by differences in tissue water proton relaxation behavior. However, many aspects of water proton relaxation in complex biological media, such as protein solutions and tissue are not well understood, perhaps due to the limited empirical data. Principal Findings Water proton T1, T2, and T1ρ of protein solutions and tissue were measured systematically under multiple conditions. Crosslinking or aggregation of protein decreased T2 and T1ρ, but did not change high-field T1. T1ρ dispersion profiles were similar for crosslinked protein solutions, myocardial tissue, and cartilage, and exhibited power law behavior with T1ρ(0) values that closely approximated T2. The T1ρ dispersion of mobile protein solutions was flat above 5 kHz, but showed a steep curve below 5 kHz that was sensitive to changes in pH. The T1ρ dispersion of crosslinked BSA and cartilage in DMSO solvent closely resembled that of water solvent above 5 kHz but showed decreased dispersion below 5 kHz. Conclusions Proton exchange is a minor pathway for tissue T1 and T1ρ relaxation above 5 kHz. Potential models for relaxation are discussed, however the same molecular mechanism appears to be responsible across 5 decades of frequencies from T1ρ to T1. PMID:20052404

  20. Diagnosing inborn errors of lipid metabolism with proton nuclear magnetic resonance spectroscopy.

    NARCIS (Netherlands)

    Oostendorp, M. van; Engelke, U.F.H.; Willemsen, M.A.A.P.; Wevers, R.A.

    2006-01-01

    BACKGROUND: Many severe diseases are caused by defects in lipid metabolism. As a result, patients often accumulate unusual lipids in their blood and tissues, and proper identification of these lipids is essential for correct diagnosis. In this study, we investigated the potential use of proton

  1. Development of Superconducting Combined Function Magnets for the Proton Transport Line for the J-PARC Neutrino Experiments

    CERN Document Server

    Nakamoto, Tatsushi; Anerella, Michael; Escallier, John; Fujii, T; Fukui, Yuji; Ganetis, George; Gupta, Ramesh C; Harrison, Michael; Hashiguchi, E; Higashi, Norio; Ichikawa, Atsuko; Iwamoto, Yosuke; Jain, Animesh K; Kanahara, T; Kimura, Nobuhiro; Kobayashi, Takashi; Makida, Yasuhiro; Muratore, Joseph F; Obana, Tetsuhiro; Ogitsu, T; Ohhata, Hirokatsu; Okamura, T; Orikasa, T; Parker, Brett; Sasaki, Ken Ichi; Takasaki, Minoru; Tanaka, Ken Ichi; Terashima, Akio; Tomaru, Takayuki; Wanderer, Peter; Yamamoto, Akira

    2005-01-01

    A second generation of long-baseline neutrino oscillation experiments has been proposed as one of the main projects at J-PARC jointly built by JAERI and KEK. Superconducting combined function magnets, SCFMs, will be utilized for the 50 GeV, 750 kW proton beam line for the neutrino experiment and an R&D program is in underway at KEK. The magnet is designed to provide a combined function of a dipole field of 2.6 T with a quadrupole field of 19 T/m in a coil aperture of 173.4 mm. A series of 28 magnets in the beam line will be operated DC in supercritical helium cooling below 5 K. A design feature of the SCFM is the left-right asymmetry of the coil cross section: current distributions for superimposed dipole- and quadrupole- fields are combined in a single layer coil. Another design feature is the adoption of glass-fiber reinforced phenolic plastic spacers to replace the conventional metallic collars. To evaluate this unique design, fabrication of full-scale prototype magnets is in progress at KEK and the fi...

  2. Repetitive transcranial magnetic stimulation improves consciousness disturbance in stroke patients A quantitative electroencephalography spectral power analysis

    Institute of Scientific and Technical Information of China (English)

    Ying Xie; Tong Zhang

    2012-01-01

    Repetitive transcranial magnetic stimulation is a noninvasive treatment technique that can directly alter cortical excitability and improve cerebral functional activity in unconscious patients. To investigate the effects and the electrophysiological changes of repetitive transcranial magnetic stimulation cortical treatment, 10 stroke patients with non-severe brainstem lesions and with disturbance of consciousness were treated with repetitive transcranial magnetic stimulation. A quantitative electroencephalography spectral power analysis was also performed. The absolute power in the alpha band was increased immediately after the first repetitive transcranial magnetic stimulation treatment, and the energy was reduced in the delta band. The alpha band relative power values slightly decreased at 1 day post-treatment, then increased and reached a stable level at 2 weeks post-treatment. Glasgow Coma Score and JFK Coma Recovery Scale-Revised score were improved. Relative power value in the alpha band was positively related to Glasgow Coma Score and JFK Coma Recovery Scale-Revised score. These data suggest that repetitive transcranial magnetic stimulation is a noninvasive, safe, and effective treatment technology for improving brain functional activity and promoting awakening in unconscious stroke patients.

  3. BNL alternating gradient synchrotron with four helical magnets to minimize the losses of the polarized proton beam

    Science.gov (United States)

    Tsoupas, N.; Huang, H.; MacKay, W. W.; Meot, F.; Roser, T.; Trbojevic, D.

    2013-04-01

    The principle of using multiple partial helical magnets to preserve the polarization of the proton beam during its acceleration was applied successfully to the alternating gradient synchrotron (AGS) which currently operates with two partial helical magnets. In this paper we further explore this idea by using four partial helical magnets placed symmetrically in the AGS ring. This provides many advantages over the present setup of the AGS, which uses two partial helical magnets. First, the symmetric placement of the four helical magnets and their relatively lower field of operation allows for better control of the AGS optics with reduced values of the beta functions especially near beam injection and allows both the vertical and horizontal tunes to be placed within the “spin tune gap,” therefore eliminating the horizontal and vertical intrinsic spin resonances of the AGS during the acceleration cycle. Second, it provides a wider spin tune gap. Third, the vertical spin direction during beam injection and extraction is closer to vertical. Although the spin tune gap, which is created with four partial helices, can also be created with a single or two partial helices, the high field strength of a single helical magnet which is required to generate such a spin tune gap makes the use of the single helical magnet impractical, and that of the two helical magnets rather difficult. In this paper we will provide results on the spin tune and on the optics of the AGS with four partial helical magnets, and compare them with those from the present setup of the AGS that uses two partial helical magnets. Although in this paper we specifically discuss the effect of the four partial helices on the AGS, this method which can eliminate simultaneously the vertical and horizontal intrinsic spin resonances is a general method and can be applied to any medium energy synchrotron which operates in similar energy range like the AGS and provides the required space to accommodate the four

  4. BNL alternating gradient synchrotron with four helical magnets to minimize the losses of the polarized proton beam

    Directory of Open Access Journals (Sweden)

    N. Tsoupas

    2013-04-01

    Full Text Available The principle of using multiple partial helical magnets to preserve the polarization of the proton beam during its acceleration was applied successfully to the alternating gradient synchrotron (AGS which currently operates with two partial helical magnets. In this paper we further explore this idea by using four partial helical magnets placed symmetrically in the AGS ring. This provides many advantages over the present setup of the AGS, which uses two partial helical magnets. First, the symmetric placement of the four helical magnets and their relatively lower field of operation allows for better control of the AGS optics with reduced values of the beta functions especially near beam injection and allows both the vertical and horizontal tunes to be placed within the “spin tune gap,” therefore eliminating the horizontal and vertical intrinsic spin resonances of the AGS during the acceleration cycle. Second, it provides a wider spin tune gap. Third, the vertical spin direction during beam injection and extraction is closer to vertical. Although the spin tune gap, which is created with four partial helices, can also be created with a single or two partial helices, the high field strength of a single helical magnet which is required to generate such a spin tune gap makes the use of the single helical magnet impractical, and that of the two helical magnets rather difficult. In this paper we will provide results on the spin tune and on the optics of the AGS with four partial helical magnets, and compare them with those from the present setup of the AGS that uses two partial helical magnets. Although in this paper we specifically discuss the effect of the four partial helices on the AGS, this method which can eliminate simultaneously the vertical and horizontal intrinsic spin resonances is a general method and can be applied to any medium energy synchrotron which operates in similar energy range like the AGS and provides the required space to

  5. A combined post-mortem magnetic resonance imaging and quantitative histological study of multiple sclerosis pathology.

    Science.gov (United States)

    Kolasinski, James; Stagg, Charlotte J; Chance, Steven A; Deluca, Gabriele C; Esiri, Margaret M; Chang, Eun-Hyuk; Palace, Jacqueline A; McNab, Jennifer A; Jenkinson, Mark; Miller, Karla L; Johansen-Berg, Heidi

    2012-10-01

    Multiple sclerosis is a chronic inflammatory neurological condition characterized by focal and diffuse neurodegeneration and demyelination throughout the central nervous system. Factors influencing the progression of pathology are poorly understood. One hypothesis is that anatomical connectivity influences the spread of neurodegeneration. This predicts that measures of neurodegeneration will correlate most strongly between interconnected structures. However, such patterns have been difficult to quantify through post-mortem neuropathology or in vivo scanning alone. In this study, we used the complementary approaches of whole brain post-mortem magnetic resonance imaging and quantitative histology to assess patterns of multiple sclerosis pathology. Two thalamo-cortical projection systems were considered based on their distinct neuroanatomy and their documented involvement in multiple sclerosis: lateral geniculate nucleus to primary visual cortex and mediodorsal nucleus of the thalamus to prefrontal cortex. Within the anatomically distinct thalamo-cortical projection systems, magnetic resonance imaging derived cortical thickness was correlated significantly with both a measure of myelination in the connected tract and a measure of connected thalamic nucleus cell density. Such correlations did not exist between these markers of neurodegeneration across different thalamo-cortical systems. Magnetic resonance imaging lesion analysis depicted clearly demarcated subcortical lesions impinging on the white matter tracts of interest; however, quantitation of the extent of lesion-tract overlap failed to demonstrate any appreciable association with the severity of markers of diffuse pathology within each thalamo-cortical projection system. Diffusion-weighted magnetic resonance imaging metrics in both white matter tracts were correlated significantly with a histologically derived measure of tract myelination. These data demonstrate for the first time the relevance of functional

  6. Quantitative screening of yeast surface-displayed polypeptide libraries by magnetic bead capture.

    Science.gov (United States)

    Yeung, Yik A; Wittrup, K Dane

    2002-01-01

    Magnetic bead capture is demonstrated here to be a feasible alternative for quantitative screening of favorable mutants from a cell-displayed polypeptide library. Flow cytometric sorting with fluorescent probes has been employed previously for high throughput screening for either novel binders or improved mutants. However, many laboratories do not have ready access to this technology as a result of the limited availability and high cost of cytometers, restricting the use of cell-displayed libraries. Using streptavidin-coated magnetic beads and biotinylated ligands, an alternative approach to cell-based library screening for improved mutants was developed. Magnetic bead capture probability of labeled cells is shown to be closely correlated with the surface ligand density. A single-pass enrichment ratio of 9400 +/- 1800-fold, at the expense of 85 +/- 6% binder losses, is achieved from screening a library that contains one antibody-displaying cell (binder) in 1.1 x 10(5) nondisplaying cells. Additionally, kinetic screening for an initial high affinity to low affinity (7.7-fold lower) mutant ratio of 1:95,000, the magnetic bead capture method attains a single-pass enrichment ratio of 600 +/- 200-fold with a 75 +/- 24% probability of loss for the higher affinity mutant. The observed high loss probabilities can be straightforwardly compensated for by library oversampling, given the inherently parallel nature of the screen. Overall, these results demonstrate that magnetic beads are capable of quantitatively screening for novel binders and improved mutants. The described methods are directly analogous to procedures in common use for phage display and should lower the barriers to entry for use of cell surface display libraries.

  7. Magnetic fingerprints of rolling cells for quantitative flow cytometry in whole blood

    Science.gov (United States)

    Reisbeck, Mathias; Helou, Michael Johannes; Richter, Lukas; Kappes, Barbara; Friedrich, Oliver; Hayden, Oliver

    2016-09-01

    Over the past 50 years, flow cytometry has had a profound impact on preclinical and clinical applications requiring single cell function information for counting, sub-typing and quantification of epitope expression. At the same time, the workflow complexity and high costs of such optical systems still limit flow cytometry applications to specialized laboratories. Here, we present a quantitative magnetic flow cytometer that incorporates in situ magnetophoretic cell focusing for highly accurate and reproducible rolling of the cellular targets over giant magnetoresistance sensing elements. Time-of-flight analysis is used to unveil quantitative single cell information contained in its magnetic fingerprint. Furthermore, we used erythrocytes as a biological model to validate our methodology with respect to precise analysis of the hydrodynamic cell diameter, quantification of binding capacity of immunomagnetic labels, and discrimination of cell morphology. The extracted time-of-flight information should enable point-of-care quantitative flow cytometry in whole blood for clinical applications, such as immunology and primary hemostasis.

  8. A Direct Search for Stable Magnetic Monopoles Produced in Positron-Proton Collisions at HERA

    CERN Document Server

    Aktas, A; Anthonis, T; Aplin, S; Asmone, A; Babaev, A; Backovic, S; Bähr, J; Baghdasaryan, A; Baranov, P; Barrelet, E; Bartel, Wulfrin; Baudrand, S; Baumgartner, S; Becker, J; Beckingham, M; Behnke, O; Behrendt, O; Belousov, A; Berger, C; Berger, N; Bizot, J C; Boenig, M O; Boudry, V; Bracinik, J; Brandt, G; Brisson, V; Brown, D P; Bruncko, Dusan; Büsser, F W; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Caron, S; Cassol-Brunner, F; Cerny, K; Chekelian, V; Contreras, J G; Coughlan, J A; Cox, B E; Cozzika, G; Cvach, J; Dainton, J B; Dau, W D; Daum, K; Delcourt, B; Demirchyan, R; de Roeck, A; Desch, Klaus; De Wolf, E A; Diaconu, C; Dodonov, V; Dubak, A; Eckerlin, G; Efremenko, V; Egli, S; Eichler, R; Eisele, F; Ellerbrock, M; Elsen, E; Erdmann, W; Essenov, S; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Ferencei, J; Finke, L; Fleischer, M; Fleischmann, P; Fleming, Y H; Flucke, G; Fomenko, A; Foresti, I; Formánek, J; Franke, G; Frising, G; Frisson, T; Gabathuler, Erwin; Garutti, E; Gayler, J; Gerhards, R; Gerlich, C; Ghazaryan, S; Ginzburgskaya, S; Glazov, A; Glushkov, I; Görlich, L; Göttlich, M; Gogitidze, N; Gorbounov, S; Goyon, C; Grab, C; Greenshaw, T; Gregori, M; Grindhammer, G; Gwilliam, C; Haidt, D; Hajduk, L; Haller, J; Hansson, M; Heinzelmann, G; Henderson, R C W; Henschel, H; Henshaw, O; Herrera-Corral, G; Herynek, I; Heuer, R D; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R P; Hovhannisyan, A; Ibbotson, M; Ismail, M; Jacquet, M; Janauschek, L; Janssen, X; Jemanov, V; Jönsson, L B; Johnson, D P; Jung, H; Kapichine, M; Karlsson, M; Katzy, J; Keller, N; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Klimkovich, T; Kluge, T; Knies, G; Knutsson, A; Korbel, V; Kostka, P; Koutouev, R; Krastev, K; Kretzschmar, J; Kropivnitskaya, A; Krüger, K; Kuckens, J; Landon, M P J; Lange, W; Lastoviicka, T; Laycock, P; Lebedev, A; Leiner, B; Lendermann, V; Levonian, S; Lindfeld, L; Lipka, K; List, B; Lobodzinska, E; Loktionova, N; López-Fernandez, R; Lubimov, V; Lucaci-Timoce, A I; Lüders, H; Lüke, D; Lux, T; Lytkin, L; Makankine, A; Malden, N; Malinovskii, E I; Mangano, S; Marage, P; Marshall, R; Martisikova, M; Martyn, H U; Maxfield, S J; Meer, D; Mehta, A; Meier, K; Meyer, A B; Meyer, H; Meyer, J; Mikocki, S; Milcewicz-Mika, I; Milstead, D; Mohamed, A; Moreau, F; Morozov, A; Morris, J V; Mozer, M U; Müller, K; Murn, P; Nankov, K; Naroska, Beate; Naumann, J; Naumann, T; Newman, P R; Niebuhr, C B; Nikiforov, A; Nikitin, D K; Nowak, G; Nozicka, M; Oganezov, R; Olivier, B; Olsson, J E; Osman, S; Ozerov, D; Pascaud, C; Patel, G D; Peez, M; Pérez, E; Perez-Astudillo, D; Perieanu, A; Petrukhin, A; Pitzl, D; Placakyte, R; Pöschl, R; Portheault, B; Povh, B; Prideaux, P; Raicevic, N; Reimer, P; Rimmer, A; Risler, C; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rurikova, Z; Rusakov, S V; Salvaire, F; Sankey, D P C; Sauvan, E; Schatzel, S; Scheins, J; Schilling, F P; Schmidt, S; Schmitt, S; Schmitz, C; Schoeffel, L; Schöning, A; Schröder, V; Schultz-Coulon, H C; Schwanenberger, C; Sedlak, K; Sefkow, F; Shevyakov, I; Shtarkov, L N; Sirois, Y; Sloan, T; Smirnov, P; Soloviev, Yu; South, D; Spaskov, V; Specka, A; Stella, B; Stiewe, J; Strauch, I; Straumann, U; Tchoulakov, V; Thompson, G; Thompson, P D; Tomasz, F; Traynor, D; Truöl, P; Tsakov, I; Tsipolitis, G; Tsurin, I; Turnau, J; Tzamariudaki, E; Urban, M; Usik, A; Utkin, D; Valkár, S; Valkárová, A; Vallée, C; Van Mechelen, P; Van Remortel, N; Vargas-Trevino, A; Vazdik, Ya A; Veelken, C; Vest, A; Vinokurova, S; Volchinski, V; Vujicic, B; Wacker, K; Wagner, J; Weber, G; Weber, R; Wegener, D; Werner, C; Werner, N; Wessels, M; Wessling, B; Wigmore, C; Winter, G G; Wissing, C; Wolf, R; Wünsch, E; Xella, S M; Yan, W; Yeganov, V; Zaicek, J; Zaleisak, J; Zhang, Z; Zhelezov, A; Zhokin, A; Zimmermann, J; Zohrabyan, H G; Zomer, F

    2005-01-01

    A direct search has been made for magnetic monopoles produced in e^+ p collisions at a centre of mass energy of 300 GeV at HERA. The beam pipe surrounding the interaction region in 1995-1997 was investigated using a SQUID magnetometer to look for stopped magnetic monopoles. During this time an integrated luminosity of 62 pb^{-1} was delivered. No magnetic monopoles were observed and charge and mass dependent upper limits on the e^+ p production cross section are set.

  9. Exploring the mechanism of IR-UV double-resonance for quantitative spectroscopy of protonated polypeptides and proteins.

    Science.gov (United States)

    Nagornova, Natalia S; Rizzo, Thomas R; Boyarkin, Oleg V

    2013-06-03

    Spectroscopic fingerprint: Infrared–ultraviolet double resonance photodissociation is used for conformational assignment of the electronic spectra of a cold protonated decapeptide (see picture). A mechanism of the IR–UV depletion spectroscopy is proposed and a procedure of using it for measurements of absolute absorption cross-sections of vibrational transitions is elaborated.

  10. Proton Magnetic Resonance Spectroscopy-Detected Changes of Marrow Fat Content in a Rabbit Model of Osteoporosis Treated With Epigallocatechin-3-Gallate.

    Science.gov (United States)

    Liu, Yin; Wu, Sijie; Cui, Rongrong; Chan, Qian; Zhang, Shengwang; Liao, Yunjie; Huang, Can

    The aim of this study was to longitudinally evaluate the changes in marrow fat content of ovariectomized (OVX) rabbits treated with epigallocatechin-3-gallate (EGCG) using proton magnetic resonance spectroscopy (H-MRS). Thirty-six female New Zealand rabbits were equally divided into sham operation, OVX controls, and OVX treated with EGCG (intraperitoneally, 1.8 mg/kg) for 5 months. Marrow fat fraction by H-MRS and bone density by peripheral quantitative computed tomography were determined at 0, 3, and 5 months. Serum biomarkers and marrow adipocytes were determined at the end of experiment. Estrogen deficiency increased marrow fat content in a time-dependent manner, with a variation of marrow fat fraction (FF) (+25.3%) at month 3 from baseline, and it was maintained until month 5 (+66.6%, all P EGCG treatment. In addition, EGCG treatment reduced bone turnover and increased bone density of OVX rabbits. Epigallocatechin-3-gallate exhibits an anabolic effect on osteoporotic bone by concomitantly rescuing bone mass and mitigating marrow adiposity. H-MRS appears to be a useful tool for monitoring osteoporosis-related treatments.

  11. A new two-dimensional approach to quantitative prediction for collision cross-section of more than 110 singly protonated peptides by a novel moecular electronegativity-interaction vector through quantitative structure-spectrometry relationship studies

    Institute of Scientific and Technical Information of China (English)

    ZHOU Peng; MEI Hu; TIAN Feifei; WANG Jiaona; WU Shirong; LI Zhiliang

    2007-01-01

    Based on two-dimensional topological characters,a novel method called molecular electronegativityinteraction vector(MEIV)is proposed to parameterize molecular structures.Applying MEIV into quantitative structure-spectrometry relationship studies on ion mobility spectrometry collision cross-sections of 113 singly protonated peptides,three models were strictly obtained,with correlative coefficient r and leave-one-out cross-validation q of 0.983,0.979,0.981,0.979 and 0.980,0.978,respectively.Thus,the MEIV is confirmed to be potent to structural characterizations and property predictions for organic and biologic molecules.

  12. Association between preoperative magnetic resonance imaging, pain intensity and quantitative sensory testing in patients awaiting lumbar diskectomy.

    LENUS (Irish Health Repository)

    Hegarty, Dominic

    2011-02-01

    Magnetic resonance imaging (MRI) offers important information regarding the morphology, location and size of a herniated disc, which influences the decision to offer lumbar diskectomy (LD). This study aims to examine the association between clinical neurophysiologic indices including pain intensity and quantitative sensory testing (QST), and the degree of lumbar nerve root compromise depicted on magnetic resonance (MR) in patients awaiting LD.

  13. In vivo proton magnetic resonance spectroscopy of intraventricular tumours of the brain

    Energy Technology Data Exchange (ETDEWEB)

    Majos, Carles; Aguilera, Carles [Hospital Universitari de Bellvitge, Institut de Diagnostic per la Imatge (IDI). Centre Bellvitge, L' Hospitalet de Llobregat, Barcelona (Spain); Biomateriales y Nanomedicina (CIBER-BBN), Centro de Investigacion Biomedica en Red en Bioingenieria, Cerdanyola del Valles (Spain); Cos, Monica; Camins, Angels; Samitier, Alex; Castaner, Sara; Sanchez, Juan J. [Hospital Universitari de Bellvitge, Institut de Diagnostic per la Imatge (IDI). Centre Bellvitge, L' Hospitalet de Llobregat, Barcelona (Spain); Candiota, Ana P.; Delgado-Goni, Teresa [Biomateriales y Nanomedicina (CIBER-BBN), Centro de Investigacion Biomedica en Red en Bioingenieria, Cerdanyola del Valles (Spain); Unitat de Bioquimica de Biociencies, Department de Bioquimica i Biologia Molecular, Cerdanyola del Valles (Spain); Mato, David [Hospital Universitari de Bellvitge, Department of Neurosurgery, L' Hospitalet de Llobregat, Barcelona (Spain); Acebes, Juan J. [Hospital Universitari de Bellvitge, Department of Neurosurgery, L' Hospitalet de Llobregat, Barcelona (Spain); Biomateriales y Nanomedicina (CIBER-BBN), Centro de Investigacion Biomedica en Red en Bioingenieria, Cerdanyola del Valles (Spain); Arus, Carles [Unitat de Bioquimica de Biociencies, Department de Bioquimica i Biologia Molecular, Cerdanyola del Valles (Spain); Biomateriales y Nanomedicina (CIBER-BBN), Centro de Investigacion Biomedica en Red en Bioingenieria, Cerdanyola del Valles (Spain)

    2009-08-15

    The aim of this study was to assess the usefulness of proton MR spectroscopy in the diagnosis of intraventricular tumours. Fifty-two intraventricular tumours pertaining to 16 different tumour types were derived from our database. All cases had single-voxel proton MR spectroscopy performed at TE at both 30 and 136 ms at 1.5 T. The Mann-Whitney U test was used to search for the most discriminative datapoints each tumour type. Characteristic trends were found for some groups: high Glx and Ala in meningiomas (p<0.001 and p<0.01, respectively), high mobile lipids in metastasis (p<0.001), high Cho in PNET (p<0.001), high mI+Gly in ependymoma (p<0.001), high NAC (p<0.01) in the absence of the normal brain parenchyma pattern in colloid cysts, and high mI/Gly and Ala in central neurocytoma. Proton MR spectroscopy provides additional metabolic information that could be useful in the diagnosis of intraventricular brain tumors. (orig.)

  14. Finger joint synovitis in rheumatoid arthritis: quantitative assessment by magnetic resonance imaging

    DEFF Research Database (Denmark)

    Klarlund, Mette; Østergaard, Mikkel; Lorenzen, I

    1999-01-01

    -quantitative score for hypertrophic synovial membrane. PATIENTS AND METHODS: MCP joints of the dominant hand of 37 patients and five controls were examined clinically and by MRI. Laboratory assessments were performed. RESULTS: Median synovial membrane volumes were considerably larger in clinically active rheumatoid......OBJECTIVE: To assess quantitatively, by magnetic resonance imaging (MRI), the synovial membrane volume in second to fifth metacarpophalangeal (MCP) joints in patients with rheumatoid arthritis and healthy controls, and to compare the synovial membrane volumes with a more easily obtained semi...... with the synovial volumes (Spearman rho = 0.79; P rheumatoid factor and to laboratory markers of inflammation. CONCLUSION: These findings suggest that synovial membrane volumes, as determined by MRI, in finger joints are related...

  15. Brain iron deposition in essential tremor: a quantitative 3-Tesla magnetic resonance imaging study.

    Science.gov (United States)

    Novellino, Fabiana; Cherubini, Andrea; Chiriaco, Carmelina; Morelli, Maurizio; Salsone, Maria; Arabia, Gennarina; Quattrone, Aldo

    2013-02-01

    Studies have demonstrated brain iron deposition in neurodegenerative disease and in normal aging. Data on this topic are lacking in essential tremor (ET). The aim of our study was to investigate brain iron content in patients with ET, using quantitative magnetic resonance imaging (MRI) T2*-relaxometry. We enrolled 24 patients with ET and 25 age-matched healthy controls. Subjects were examined using a 3T MRI scanner. The protocol included conventional MRI sequences and quantitative T2*-relaxometry. Whole-brain voxel-based analyses showed significant differences in T2* values in bilateral globus pallidus, substantia nigra, and in right dentate nucleus (P motor systems outside of the cerebellum/cerebellar pathway and, more specifically, of the globus pallidus. Copyright © 2012 Movement Disorders Society.

  16. Proton and phosphorus magnetic resonance spectroscopy of the healthy human breast at 7 T

    NARCIS (Netherlands)

    van der Kemp, Wybe J M; Stehouwer, Bertine L; Boer, Vincent O; Luijten, Peter R; Klomp, DWJ; Wijnen, Jannie P

    In vivo water- and fat-suppressed (1) H magnetic resonance spectroscopy (MRS) and (31) P magnetic resonance adiabatic multi-echo spectroscopic imaging were performed at 7 T in duplicate in healthy fibroglandular breast tissue of a group of eight volunteers. The transverse relaxation times of (31) P

  17. Quantitative Determination on Ionic-Liquid-Gating Control of Interfacial Magnetism.

    Science.gov (United States)

    Zhao, Shishun; Zhou, Ziyao; Peng, Bin; Zhu, Mingmin; Feng, Mengmeng; Yang, Qu; Yan, Yuan; Ren, Wei; Ye, Zuo-Guang; Liu, Yaohua; Liu, Ming

    2017-03-03

    Ionic-liquid gating on a functional thin film with a low voltage has drawn a lot of attention due to rich chemical, electronic, and magnetic phenomena at the interface. Here, a key challenge in quantitative determination of voltage-controlled magnetic anisotropy (VCMA) in Au/[DEME](+) [TFSI](-) /Co field-effect transistor heterostructures is addressed. The magnetic anisotropy change as response to the gating voltage is precisely detected by in situ electron spin resonance measurements. A reversible change of magnetic anisotropy up to 219 Oe is achieved with a low gating voltage of 1.5 V at room temperature, corresponding to a record high VCMA coefficient of ≈146 Oe V(-1) . Two gating effects, the electrostatic doping and electrochemical reaction, are distinguished at various gating voltage regions, as confirmed by X-ray photoelectron spectroscopy and atomic force microscopy experiments. This work shows a unique ionic-liquid-gating system for strong interfacial magnetoelectric coupling with many practical advantages, paving the way toward ion-liquid-gating spintronic/electronic devices.

  18. Continuous monitoring of the zinc-phosphate acid-base cement setting reaction by proton nuclear magnetic relaxation

    Science.gov (United States)

    Apih, T.; Lebar, A.; Pawlig, O.; Trettin, R.

    2001-06-01

    Proton nuclear magnetic relaxation is a well-established technique for continuous and non destructive monitoring of hydration of conventional Portland building cements. Here, we demonstrate the feasibility of nuclear magnetic resonance (NMR) monitoring of the setting reaction of zinc-phosphate acid-base dental cements, which harden in minutes as compared to days, as in the case of Portland cements. We compare the setting of cement powder (mainly, zinc oxide) prepared with clinically used aluminum-modified orthophosphoric acid solution with the setting of a model system where cement powder is mixed with pure orthophosphoric acid solution. In contrast to previously published NMR studies of setting Portland cements, where a decrease of spin-lattice relaxation time is attributed to enhanced relaxation at the growing internal surface, spin-lattice relaxation time T1 increases during the set of clinically used zinc-phosphate cement. Comparison of these results with a detailed study of diffusion, viscosity, and magnetic-field dispersion of T1 in pure and aluminum-modified orthophosphoric acid demonstrates that the increase of T1 in the setting cement is connected with the increase of molecular mobility in the residual phosphoric acid solution. Although not taken into account so far, such effects may also significantly influence the relaxation times in setting Portland cements, particularly when admixtures with an effect on water viscosity are used.

  19. Monitoring of the proton electrochemical gradient in reconstituted vesicles: quantitative measurements of both transmembrane potential and intravesicular pH by ratiometric fluorescent probes.

    Science.gov (United States)

    Holoubek, Ales; Vecer, Jaroslav; Sigler, Karel

    2007-03-01

    Proteoliposomes carrying reconstituted yeast plasma membrane H(+)-ATPase in their lipid membrane or plasma membrane vesicles are model systems convenient for studying basic electrochemical processes involved in formation of the proton electrochemical gradient (Deltamicro(H) (+)) across the microbial or plant cell membrane. Deltapsi- and pH-sensitive fluorescent probes were used to monitor the gradients formed between inner and outer volume of the reconstituted vesicles. The Deltapsi-sensitive fluorescent ratiometric probe oxonol VI is suitable for quantitative measurements of inside-positive Deltapsi generated by the reconstituted H(+)-ATPase. Its Deltapsi response can be calibrated by the K(+)/valinomycin method and ratiometric mode of fluorescence measurements reduces undesirable artefacts. In situ pH-sensitive fluorescent probe pyranine was used for quantitative measurements of pH inside the proteoliposomes. Calibration of pH-sensitive fluorescence response of pyranine entrapped inside proteoliposomes was performed with several ionophores combined in order to deplete the gradients passively formed across the membrane. Presented model system offers a suitable tool for simultaneous monitoring of both components of the proton electrochemical gradient, Deltapsi and DeltapH. This approach should help in further understanding how their formation is interconnected on biomembranes and even how transport of other ions is combined to it.

  20. Metabolic changes in the anterior and posterior cingulate cortices of the normal aging brain: proton magnetic resonance spectroscopy study at 3 T.

    Science.gov (United States)

    Chiu, Pui-Wai; Mak, Henry Ka-Fung; Yau, Kelvin Kai-Wing; Chan, Queenie; Chang, Raymond Chuen-Chung; Chu, Leung-Wing

    2014-02-01

    Magnetic resonance spectroscopy (MRS) can explore aging at a molecular level. In this study, we investigated the relationships between regional concentrations of metabolites (such as choline, creatine, myo-inositol, and N-acetyl-aspartate) and normal aging in 30 cognitively normal subjects (15 women and 15 men, age range 22-82, mean = 49.9 ± 18.3 years) using quantitative proton magnetic resonance spectroscopy. All MR scans were performed using a 3 T scanner. Point resolved spectroscopy was used as the volume selection method for the region-of-interest and the excitation method for water suppression. Single voxel spectroscopy with short echo time of 39 ms and repetition time of 2,000 ms was employed. Single voxels were placed in the limbic regions, i.e., anterior cingulate cortex (ACC), posterior cingulate cortex (PCC), and left and right hippocampi. Cerebrospinal fluid normalization and T1 and T2 correction factors were implemented in the calculation of absolute metabolite concentrations. A standardized T1W 3D volumetric fast field echo and axial T2-weighted fast spin-echo images were also acquired. Our results showed significant positive correlation of choline (r = 0.545, p = 0.002), creatine (r = 0.571, p = 0.001), and N-acetyl-aspartate (r = 0.674, p age. No significant gender effect on metabolite concentrations was found. In aging, increases in choline and creatine might suggest glial proliferation, and an increase in N-acetyl-aspartate might indicate neuronal hypertrophy. Such findings highlight the metabolic changes of ACC and PCC with age, which could be compensatory to an increased energy demand coupled with a lower cerebral blood flow.

  1. Measurements of the Backstreaming Proton IONS in the Self-Magnetic Pinch (SMP) Diode Utilizing Copper Activation Technique

    Science.gov (United States)

    Mazarakis, Michael; Cuneo, Michael; Fournier, Sean; Johnston, Mark; Kiefer, Mark; Leckbee, Joshua; Simpson, Sean; Renk, Timothy; Webb, Timothy; Bennett, Nichelle

    2016-10-01

    The results presented here were obtained with an SMP diode mounted at the front high voltage end of the 8-10-MV RITS Self-Magnetically Insulated Transmission Line (MITL) voltage adder. Our experiments had two objectives: first, to measure the contribution of the back-streaming proton currents emitted from the anode target, and second, to evaluate the energy of those ions and hence the actual Anode-Cathode (A-K) gap voltage. The accelerating voltage quoted in the literature is estimated utilizing para-potential flow theories. Thus, it is interesting to have another independent measurement of the A-K voltage. We have measured the back-streaming protons emitted from the anode and propagating through a hollow cathode tip for various diode configurations and different techniques of target cleaning treatment, namely, heating at very high temperatures with DC and pulsed current, with RF plasma cleaning, and with both plasma cleaning and heating. We have also evaluated the A-K gap voltage by energy filtering techniques. Sandia is operated by Sandia Corporation, a subsidiary of Lockheed Martin Company, for the US DOE NNSA under Contract No. DE-AC04-94AL85000.

  2. Proton nuclear magnetic resonance studies on the variant-3 neurotoxin from Centruroides sculpturatus Ewing: Sequential assignment of resonances

    Energy Technology Data Exchange (ETDEWEB)

    Nettesheim, D.G.; Klevit, R.E.; Drobny, G.; Watt, D.D.; Krishna, N.R. (Univ. of Alabama, Birmingham (USA))

    1989-02-21

    The authors report the sequential assignment of resonances to specific residues in the proton nuclear magnetic resonance spectrum of the variant-3 neurotoxin from the scorpion Centruroides sculpturatus Ewing (range southwestern U.S.A.). A combination of two-dimensional NMR experiments such as 2D-COSY, 2D-NOESY, and single- and double-RELAY coherence transfer spectroscopy has been employed on samples of the protein dissolved in D{sub 2}O and in H{sub 2}O for assignment purposes. These studies provide a basis for the determination of the solution-phase conformation of this protein and for undertaking detailed structure-function studies of these neurotoxins that modulate the flow of sodium current by binding to the sodium channels of excitable membranes.

  3. Proton magnetic resonance spectroscopy of the anterior cingulate gyrus and caudate nucleus in schizophrenia patients versus healthy controls

    Institute of Scientific and Technical Information of China (English)

    Lutfi Incesu; Meral Baydin; Kerim Aslan; Baris Diren; Huseyin Sahin; Omer Boke; Senol Dane

    2011-01-01

    Proton magnetic resonance spectroscopy (1H-MRS) permits the assessment of cerebral neurometabolites, such as N-acetylaspartate, choline, and creatine, in vivo and has been used to study schizophrenia. The present study used 1H-MRS to compare the spectroscopy change of N-acetylaspartate, creatine, and choline metabolite levels in the anterior cingulate and caudate nucleus of both schizophrenia patients and healthy controls, as well as between the left and right cerebral hemispheres in the schizophrenia patients. Results showed that N-acetylaspartate and creatine metabolite levels in the left anterior cingulate gyrus were significantly lower in the schizophrenia patients than in the healthy controls, indicating hypometabolism. In addition, choline concentration in the left caudate nucleus of schizophrenia patients was significantly lower than in the right caudate nucleus, indicating that it is necessary to study the cerebral lateralization of 1H-MRS in schizophrenia patients.

  4. The effect of polymer coatings on proton transverse relaxivities of aqueous suspensions of magnetic nanoparticles.

    Science.gov (United States)

    Carroll, Matthew R J; Huffstetler, Phillip P; Miles, William C; Goff, Jonathon D; Davis, Richey M; Riffle, Judy S; House, Michael J; Woodward, Robert C; St Pierre, Timothy G

    2011-08-12

    Iron oxide magnetic nanoparticles are good candidates for magnetic resonance imaging (MRI) contrast agents due to their high magnetic susceptibilities. Here we investigate 19 polyether-coated magnetite nanoparticle systems comprising three series. All systems were synthesized from the same batch of magnetite nanoparticles. A different polyether was used for each series. Each series comprised systems with systematically varied polyether loadings per particle. A highly significant (p coatings used in this study, any changes in relaxivity from differences in water exclusion or diffusion rates caused by the polymer are minor in comparison with the changes in relaxivity resulting from variations in the degree of aggregation.

  5. The study of hydrogen proton magnetic resonance spectroscopy of the hippocampus of patients with dementia with Lewy bodies and Alzheimer’s disease

    Institute of Scientific and Technical Information of China (English)

    钟笑梅

    2013-01-01

    Objective To investigate the characteristics of hydrogen proton magnetic resonance spectroscopy(1H-MRS) in the bilateral hippocampus in patients with dementia with Lewy bodies(DLB) and Alzheimer’s disease(AD) and their value in differentiating DLB from AD.

  6. Glutamine and Glutamate Levels in Children and Adolescents with Bipolar Disorder: A 4.0-T Proton Magnetic Resonance Spectroscopy Study of the Anterior Cingulate Cortex

    Science.gov (United States)

    Moore, Constance M.; Frazier, Jean A.; Glod, Carol A.; Breeze, Janis L.; Dieterich, Megan; Finn, Chelsea T.; deB. Frederick, Blaise; Renshaw, Perry F.

    2007-01-01

    Objective: The purpose of this study was to use proton magnetic resonance spectroscopy, at 4.0 T, to explore the glutamine and glutamate levels in the anterior cingulate cortex of children and adolescents with bipolar disorder (BPD; medicated and unmedicated) and healthy comparison subjects (HCSs). We hypothesized that unmedicated children with…

  7. Glutamine and Glutamate Levels in Children and Adolescents with Bipolar Disorder: A 4.0-T Proton Magnetic Resonance Spectroscopy Study of the Anterior Cingulate Cortex

    Science.gov (United States)

    Moore, Constance M.; Frazier, Jean A.; Glod, Carol A.; Breeze, Janis L.; Dieterich, Megan; Finn, Chelsea T.; deB. Frederick, Blaise; Renshaw, Perry F.

    2007-01-01

    Objective: The purpose of this study was to use proton magnetic resonance spectroscopy, at 4.0 T, to explore the glutamine and glutamate levels in the anterior cingulate cortex of children and adolescents with bipolar disorder (BPD; medicated and unmedicated) and healthy comparison subjects (HCSs). We hypothesized that unmedicated children with…

  8. Assessment of Anterior Cingulate Cortex (ACC) and Left Cerebellar Metabolism in Asperger's Syndrome with Proton Magnetic Resonance Spectroscopy (MRS)

    Science.gov (United States)

    Goji, Aya; Ito, Hiromichi; Mori, Kenji; Harada, Masafumi; Hisaoka, Sonoka; Toda, Yoshihiro; Mori, Tatsuo; Abe, Yoko; Miyazaki, Masahito; Kagami, Shoji

    2017-01-01

    Purpose Proton magnetic resonance spectroscopy (1H MRS) is a noninvasive neuroimaging method to quantify biochemical metabolites in vivo and it can serve as a powerful tool to monitor neurobiochemical profiles in the brain. Asperger’s syndrome (AS) is a type of autism spectrum disorder, which is characterized by impaired social skills and restrictive, repetitive patterns of interest and activities, while intellectual levels and language skills are relatively preserved. Despite clinical aspects have been well-characterized, neurometabolic profiling in the brain of AS remains to be clear. The present study used proton magnetic resonance spectroscopy (1H MRS) to investigate whether pediatric AS is associated with measurable neurometabolic abnormalities that can contribute new information on the neurobiological underpinnings of the disorder. Methods Study participants consisted of 34 children with AS (2–12 years old; mean age 5.2 (±2.0); 28 boys) and 19 typically developed children (2–11 years old; mean age 5.6 (±2.6); 12 boys) who served as the normal control group. The 1H MRS data were obtained from two regions of interest: the anterior cingulate cortex (ACC) and left cerebellum. Results In the ACC, levels of N-acetylaspartate (NAA), total creatine (tCr), total choline-containing compounds (tCho) and myo-Inositol (mI) were significantly decreased in children with AS compared to controls. On the other hand, no significant group differences in any of the metabolites were found in the left cerebellum. Neither age nor sex accounted for the metabolic findings in the regions. Conclusion The finding of decreased levels of NAA, tCr, tCho, and mI in the ACC but not in left cerebellar voxels in the AS, suggests a lower ACC neuronal density in the present AS cohort compared to controls. PMID:28060873

  9. Pattern recognition analysis of proton nuclear magnetic resonance spectra of brain tissue extracts from rats anesthetized with propofol or isoflurane.

    Directory of Open Access Journals (Sweden)

    Hiroshi Kawaguchi

    Full Text Available BACKGROUND: General anesthesia is routinely used as a surgical procedure and its safety has been endorsed by clinical outcomes; however, its effects at the molecular level have not been elucidated. General anesthetics influence glucose metabolism in the brain. However, the effects of anesthetics on brain metabolites other than those related to glucose have not been well characterized. We used a pattern recognition analysis of proton nuclear magnetic resonance spectra to visualize the changes in holistic brain metabolic phenotypes in response to the widely used intravenous anesthetic propofol and the volatile anesthetic isoflurane. METHODOLOGY/PRINCIPAL FINDINGS: Rats were randomized into five groups (n = 7 each group. Propofol and isoflurane were administered to two groups each, for 2 or 6 h. The control group received no anesthesia. Brains were removed directly after anesthesia. Hydrophilic compounds were extracted from excised whole brains and measured by proton nuclear magnetic resonance spectroscopy. All spectral data were processed and analyzed by principal component analysis for comparison of the metabolite profiles. Data were visualized by plotting principal component (PC scores. In the plots, each point represents an individual sample. The propofol and isoflurane groups were clustered separately on the plots, and this separation was especially pronounced when comparing the 6-h groups. The PC scores of the propofol group were clearly distinct from those of the control group, particularly in the 6-h group, whereas the difference in PC scores was more subtle in the isoflurane group and control groups. CONCLUSIONS/SIGNIFICANCE: The results of the present study showed that propofol and isoflurane exerted differential effects on holistic brain metabolism under anesthesia.

  10. Role of Quantitative Magnetic Resonance Imaging Parameters in the Evaluation of Treatment Response in Malignant Tumors

    Institute of Scientific and Technical Information of China (English)

    Qing-Gang Xu; Jun-Fang Xian

    2015-01-01

    Objective:To elaborate the role of quantitative magnetic resonance imaging (MRI) parameters in the evaluation of treatment response in malignant tumors.Data Sources:Data cited in this review were obtained mainly from PubMed in English from 1999 to 2014,with keywords "dynamic contrast-enhanced (DCE)-MRI," "diffusion-weighted imaging (DWI)," "microcirculation," "apparent diffusion coefficient (ADC)," "treatment response" and "oncology."Study Selection:Articles regarding principles of DCE-MRI,principles of DWI,clinical applications as well as opportunity and aspiration were identified,retrieved and reviewed.Results:A significant correlation between ADC values and treatment response was reported in most DWI studies.Most quantitative DCE-MRI studies showed a significant correlation between K~s values and treatment response.However,in different tumors and studies,both high and low pretreatment ADC or K~s values were found to be associated with response rate.Both DCE-MRI and DWI demonstrated changes in their parameters hours to days after treatment,showing a decrease in K~ns or an increase in ADC associated with response in most cases.Conclusions:Combinations of quantitative MRI play an important role in the evaluation of treatment response of malignant tumors and hold promise for use as a cancer treatment response biomarker.However,validation is hampered by the lack of reproducibility and standardization.MRI acquisition protocols and quantitative image analysis approaches should be properly addressed prior to further testing the clinical use of quantitative MRI parameters in the assessment of treatments.

  11. Sensitive, simultaneous quantitation of two unlabeled DNA targets using a magnetic nanoparticle-enzyme sandwich assay.

    Science.gov (United States)

    Zhang, Yue; Pilapong, Chalermchai; Guo, Yuan; Ling, Zhenlian; Cespedes, Oscar; Quirke, Philip; Zhou, Dejian

    2013-10-01

    We report herein the development of a simple, sensitive colorimetric magnetic nanoparticle (MNP)-enzyme-based DNA sandwich assay that is suitable for simultaneous, label-free quantitation of two DNA targets down to 50 fM level. It can also effectively discriminate single-nucleotide polymorphisms (SNPs) in genes associated with human cancers (KRAS codon 12/13 SNPs). This assay uses a pair of specific DNA probes, one being covalently conjugated to an MNP for target capture and the other being linked to an enzyme for signal amplification, to sandwich a DNA target, allowing for convenient magnetic separation and subsequent efficient enzymatic signal amplification for high sensitivity. Careful optimization of the MNP surfaces and assay conditions greatly reduced the background, allowing for sensitive, specific detection of as little as 5 amol (50 fM in 100 μL) of target DNA. Moreover, this sensor is robust, it can effectively discriminate cancer-specific SNPs against the wild-type noncancer target, and it works efficiently in 10% human serum. Furthermore, this sensor can simultaneously quantitate two different DNA targets by using two pairs of unique capture- and signal-DNA probes specific for each target. This general, simple, and sensitive DNA sensor appears to be well-suited for a wide range of genetics-based biosensing and diagnostic applications.

  12. μ-ViP: Customized virtual phantom for quantitative magnetic resonance micro-imaging at high magnetic field

    Science.gov (United States)

    Rondeau-Mouro, C.; Kovrlija, R.; Gambarota, G.; Saint-Jalmes, H.

    2017-02-01

    The applications of Magnetic Resonance micro-Imaging (MRμI) cover nowadays a wide range of fields. However few of them present quantitative measurements when the sample of interest changes over time or in case of a long acquisition time. In this domain, two challenges have to be overcome: the introduction of a phantom as a reference signal and the guarantee that this signal is stable over the experiment duration while some conditions such as temperature and/or the moisture are varied. The aim of the present study was to implement a dedicated experimental set-up to generate a virtual phantom (ViP) signal in a vertical-bore 11.7 T NMR spectrometer, equipped with a micro-imaging probe. This study shows that the generation of a micro-imaging-dedicated ViP (μ-ViP) signal is of great benefit for on-line quality control of the spectrometer performance during acquisition in the case of real-time experiments. Thus, μViP represents a step towards improvement of the magnetic resonance signal quantification in small samples.

  13. Clinical applications of proton magnetic resonance spectroscopy of the brain; Klinische Anwendungen der Protonen-Magnetresonanzspektroskopie des Gehirns

    Energy Technology Data Exchange (ETDEWEB)

    Laubenberger, J.; Bayer, S.; Thiel, T.; Hennig, J.; Langer, M. [Radiologische Universitaetsklinik Freiburg (Germany). Abt. Roentgendiagnostik

    1998-06-01

    In spite of all the scientific advances of the past few years, proton magnetic resonance spectroscopy of the brain has not attained the status of a routine examination technique with clinically accepted indications. The method should be considered as an additional option to MR imaging for inherited and acquired encephalopathic changes as well as, in future, for localization diagnosis of epilepsies. A proton magnetic resonance spectroscopic investigation without a prior intensive clinical and imaging investigation is not useful. Above all, factors influencing metabolite distribution such as for example, serum osmolability must be known. Methodological prerequisites for the clinical application of proton resonance spectroscopy are, first of all, a high stability of the chosen technique as well as a sufficiently certain quantification of metabolites and the availability of a reference group. The use of short echo times is necessary for the quantification of glutamine and the osmolyte myo-inositol. Indications for individual cases in which clinical investigations and MR topography cannot provide sufficient certainty and spectroscopy can furnish additional information are, in addition to uses in neuropediatrics, the suspicion of Alzheimer`s dementia, HIV encephalopathy in early manifestations, and unclarified depressions of consciousness accompanying liver cirrhosis. (orig.) [Deutsch] Die Protonen-Magnetresonanzspektroskopie des Gehirns ist trotz aller wissenschaftlicher Fortschritte der letzten Jahre noch nicht zu einer Routineuntersuchung mit anerkannter klinischer Indikationsstellung geworden. Die Untersuchung muss bei angeborenen und erworbenen enzephalopathischen Veraenderungen sowie in Zukunft in der Lokalisationsdiagnostik von Epilepsien als Zusatzoption zur MR-Bildgebung erachtet werden. Eine protonenspektroskopische Untersuchung ohne ausgiebige klinische und bildgebende Basisuntersuchung ist nicht sinnvoll. Insbesondere muessen Einflussfaktoren, wie z

  14. Prediction and compensation of magnetic beam deflection in MR-integrated proton therapy: a method optimized regarding accuracy, versatility and speed

    Science.gov (United States)

    Schellhammer, Sonja M.; Hoffmann, Aswin L.

    2017-02-01

    The integration of magnetic resonance imaging (MRI) and proton therapy for on-line image-guidance is expected to reduce dose delivery uncertainties during treatment. Yet, the proton beam experiences a Lorentz force induced deflection inside the magnetic field of the MRI scanner, and several methods have been proposed to quantify this effect. We analyze their structural differences and compare results of both analytical and Monte Carlo models. We find that existing analytical models are limited in accuracy and applicability due to critical approximations, especially including the assumption of a uniform magnetic field. As Monte Carlo simulations are too time-consuming for routine treatment planning and on-line plan adaption, we introduce a new method to quantify and correct for the beam deflection, which is optimized regarding accuracy, versatility and speed. We use it to predict the trajectory of a mono-energetic proton beam of energy E 0 traversing a water phantom behind an air gap within an omnipresent uniform transverse magnetic flux density B 0. The magnetic field induced dislocation of the Bragg peak is calculated as function of E 0 and B 0 and compared to results obtained with existing analytical and Monte Carlo methods. The deviation from the Bragg peak position predicted by Monte Carlo simulations is smaller for the new model than for the analytical models by up to 2 cm. The model is faster than Monte Carlo methods, less assumptive than the analytical models and applicable to realistic magnetic fields. To compensate for the predicted Bragg peak dislocation, a numerical optimization strategy is introduced and evaluated. It includes an adjustment of both the proton beam entrance angle and energy of up to 25° and 5 MeV, depending on E 0 and B 0. This strategy is shown to effectively reposition the Bragg peak to its intended location in the presence of a magnetic field.

  15. Prediction and compensation of magnetic beam deflection in MR-integrated proton therapy: a method optimized regarding accuracy, versatility and speed.

    Science.gov (United States)

    Schellhammer, Sonja M; Hoffmann, Aswin L

    2017-02-21

    The integration of magnetic resonance imaging (MRI) and proton therapy for on-line image-guidance is expected to reduce dose delivery uncertainties during treatment. Yet, the proton beam experiences a Lorentz force induced deflection inside the magnetic field of the MRI scanner, and several methods have been proposed to quantify this effect. We analyze their structural differences and compare results of both analytical and Monte Carlo models. We find that existing analytical models are limited in accuracy and applicability due to critical approximations, especially including the assumption of a uniform magnetic field. As Monte Carlo simulations are too time-consuming for routine treatment planning and on-line plan adaption, we introduce a new method to quantify and correct for the beam deflection, which is optimized regarding accuracy, versatility and speed. We use it to predict the trajectory of a mono-energetic proton beam of energy E 0 traversing a water phantom behind an air gap within an omnipresent uniform transverse magnetic flux density B 0. The magnetic field induced dislocation of the Bragg peak is calculated as function of E 0 and B 0 and compared to results obtained with existing analytical and Monte Carlo methods. The deviation from the Bragg peak position predicted by Monte Carlo simulations is smaller for the new model than for the analytical models by up to 2 cm. The model is faster than Monte Carlo methods, less assumptive than the analytical models and applicable to realistic magnetic fields. To compensate for the predicted Bragg peak dislocation, a numerical optimization strategy is introduced and evaluated. It includes an adjustment of both the proton beam entrance angle and energy of up to 25° and 5 MeV, depending on E 0 and B 0. This strategy is shown to effectively reposition the Bragg peak to its intended location in the presence of a magnetic field.

  16. Complete Electric and Magnetic Dipole Response of 208Pb from Zero-Degree Inelastic Proton Scattering

    Science.gov (United States)

    von Neumann-Cosel, P.

    2015-11-01

    Small-angle polarized proton scattering including 0° off 208Pb has been studied at the RCNP cyclotron with high energy resolution of the order of 25 keV (FWHM). The complete E1 strength distribution from 5 to 20 MeV could be extracted from the data and is found to agree well with available data. New E1 strength is found in the energy region above threshold inacessible in previous experiments. The total E1 polarizability as well as the properties of the pygmy dipole resonance could be determined with high precision providing important experimental constraints on the neutron skin thickness in 208Pb and the symmetry energy of neutron-rich matter. Additionally, information on the spin-M1 strength in 208Pb was obtained. Assuming dominance of the central spin-isospinflip part of the effective proton-nucleus interaction, the B(M1) transition strength can be derived. It corresponds well with data from electromagnetic probes indicating that the reaction can provide information on the poorly known spin-M1 resonance in heavy nuclei.

  17. 7 Tesla proton magnetic resonance spectroscopic imaging in adult X-linked adrenoleukodystrophy

    Science.gov (United States)

    Ratai, Eva; Kok, Trina; Wiggins, Christopher; Wiggins, Graham; Grant, Ellen; Gagoski, Borjan; O'Neill, Gilmore; Adalsteinsson, Elfar; Eichler, Florian

    2010-01-01

    Background Adult patients with X-linked adrenoleukodystrophy (X-ALD) remain at risk for progressive neurological deterioration. Phenotypes vary in their pathology, ranging from axonal degeneration to inflammatory demyelination. The severity of symptoms is poorly explained by conventional imaging. Objective To test the hypothesis that neurochemistry in normal appearing brain differs among adult phenotypes of X-ALD, and that neurochemical changes correlate with the severity of symptoms. Patients and Methods Using a 7 Tesla scanner we performed structural and proton MRSI in 13 adult patients with X-ALD, including 4 patients with adult cerebral ALD (ACALD), 5 with adrenomyeloneuropathy (AMN) and 4 female heterozygotes. Studies were also performed in nine healthy controls. Results Among adult X-ALD phenotypes, MI/Cr was 46% higher and Cho/Cr 21% higher in normal appearing white matter of ACALD compared to AMN (p Tesla proton MRSI reveals differences in the neurochemistry of ACALD but is unable to distinguish AMN from female heterozygotes. MI/Cr correlates with the severity of the symptoms and may be a meaningful biomarker in adult X-ALD. PMID:19001168

  18. Proton and iodine-127 nuclear magnetic resonance studies on the binding of iodide by lactoperoxidase

    Energy Technology Data Exchange (ETDEWEB)

    Sakurada, J.; Takahashi, S.; Shimizu, T.; Hatano, M.; Nakamura, S.; Hosoya, T.

    1987-10-06

    Interaction of an iodide ion with lactoperoxidase was studied by the use of /sup 1/H NMR, /sup 127/I NMR, and optical difference spectrum techniques. /sup 1/H NMR spectra demonstrated that a major broad hyperfine-shifted signal at about 60 ppm, which is ascribed to the heme peripheral methyl protons, was shifted toward high field by adding KI, indicating the binding of iodide to the active site of the enzyme; the dissociation constant was estimated to be 38 mM at pH 6.1. The binding was further detected by /sup 127/I NMR, showing no competition with cyanide. Both /sup 1/H NMR and /sup 127/I NMR revealed that the binding of iodide to the enzyme is facilitated by the protonation of an ionizable group with a pK/sup a/ value of 6.0-6.8, which is presumably the distal histidyl residue. Optical difference spectra showed that the binding of an aromatic donor molecule to the enzyme is slightly but distinctly affected by adding KI. On the basis of these results, it was suggested that an iodide ion binds to lactoperoxidase outside the heme crevice but at the position close enough to interact with the distal histidyl residue which possibly mediates electron transport in the iodide oxidation reaction.

  19. Quantitative morphologic evaluation of magnetic resonance imaging during and after treatment of childhood leukemia

    Energy Technology Data Exchange (ETDEWEB)

    Reddick, Wilburn E.; Glass, John O. [St. Jude Children' s Research Hospital, Division of Translational Imaging Research (MS 210), Department of Radiological Sciences, Memphis, TN (United States); Laningham, Fred H. [St. Jude Children' s Research Hospital, Division of Diagnostic Imaging, Memphis, TN (United States); Pui, Ching-Hon [St. Jude Children' s Research Hospital, Department of Oncology, Memphis, TN (United States)

    2007-11-15

    Medical advances over the last several decades, including CNS prophylaxis, have greatly increased survival in children with leukemia. As survival rates have increased, clinicians and scientists have been afforded the opportunity to further develop treatments to improve the quality of life of survivors by minimizing the long-term adverse effects. When evaluating the effect of antileukemia therapy on the developing brain, magnetic resonance (MR) imaging has been the preferred modality because it quantifies morphologic changes objectively and noninvasively. Computer-aided detection of changes on neuroimages enables us to objectively differentiate leukoencephalopathy from normal maturation of the developing brain. Quantitative tissue segmentation algorithms and relaxometry measures have been used to determine the prevalence, extent, and intensity of white matter changes that occur during therapy. More recently, diffusion tensor imaging has been used to quantify microstructural changes in the integrity of the white matter fiber tracts. MR perfusion imaging can be used to noninvasively monitor vascular changes during therapy. Changes in quantitative MR measures have been associated, to some degree, with changes in neurocognitive function during and after treatment. In this review, we present recent advances in quantitative evaluation of MR imaging and discuss how these methods hold the promise to further elucidate the pathophysiologic effects of treatment for childhood leukemia. (orig.)

  20. Multiparametric Classification of Skin from Osteogenesis Imperfecta Patients and Controls by Quantitative Magnetic Resonance Microimaging.

    Directory of Open Access Journals (Sweden)

    Beth G Ashinsky

    Full Text Available The purpose of this study is to evaluate the ability of quantitative magnetic resonance imaging (MRI to discriminate between skin biopsies from individuals with osteogenesis imperfecta (OI and skin biopsies from individuals without OI. Skin biopsies from nine controls (unaffected and nine OI patients were imaged to generate maps of five separate MR parameters, T1, T2, km, MTR and ADC. Parameter values were calculated over the dermal region and used for univariate and multiparametric classification analysis. A substantial degree of overlap of individual MR parameters was observed between control and OI groups, which limited the sensitivity and specificity of univariate classification. Classification accuracies ranging between 39% and 67% were found depending on the variable of investigation, with T2 yielding the best accuracy of 67%. When several MR parameters were considered simultaneously in a multivariate analysis, the classification accuracies improved up to 89% for specific combinations, including the combination of T2 and km. These results indicate that multiparametric classification by quantitative MRI is able to detect differences between the skin of OI patients and of unaffected individuals, which motivates further study of quantitative MRI for the clinical diagnosis of OI.

  1. The Boiler Tube Wall Thickness Quantitative Evaluation Fusing the Magnetic and Ultrasonic Technique

    Institute of Scientific and Technical Information of China (English)

    SONG Xiaochun; HUANG Songling; ZHAO Daxing

    2006-01-01

    Wall thickness is always a key index for boiler tube inspection in power plant, in order to improve the inspection efficiency and accuracy, a new method fusing the magnetic and ultrasonic technique was proposed. The magnetic technique was used to do full inspection and locate the flaws, and the ultrasonic was employed to implement further quantitative inspection accurately. After comparing the precision of the polynomial, exponential and logarithmic function, the polynomial model was selected to fit the relations between the wall thickness and the peak value of magnetic signals, and the data measured by ultrasonic thickness meter was used to calibrate the model parameters online, the defect depth can be sized quickly. The experimental results demonstrate that the model used in this system has better accuracy than the statistics relation model clearly, and it is also suitable for defect evaluation real-time. Moreover, it is unnecessary to have much more experimental data for the curve fitting technology, so it has better practicability than the other methods.

  2. Quantitative imaging of magnetic nanoparticles by magneto-relaxometric tomography for biomedical applications; Quantitative Bildgebung magnetischer Nanopartikel mittels magnetrelaxometrischer Tomographie fuer biomedizinische Anwendungen

    Energy Technology Data Exchange (ETDEWEB)

    Liebl, Maik

    2016-11-18

    Current biomedical research focuses on the development of novel biomedical applications based on magnetic nanoparticles (MNPs), e.g. for local cancer treatment. These therapy approaches employ MNPs as remotely controlled drug carriers or local heat generators. Since location and quantity of MNPs determine drug enrichment and heat production, quantitative knowledge of the MNP distribution inside a body is essential for the development and success of these therapies. Magnetorelaxometry (MRX) is capable to provide such quantitative information based on the specific response of the MNPs after switching-off an applied magnetic field. Applying a uniform (homogeneous) magnetic field to a MNP distribution and measuring the MNP response by multiple sensors at different locations allows for spatially resolved MNP quantification. However, to reconstruct the MNP distribution from this spatially resolved MRX data, an ill posed inverse problem has to be solved. So far, the solution of this problem was stabilized incorporating a-priori knowledge in the forward model, e.g. by setting priors on the vertical position of the distribution using a 2D reconstruction grid or setting priors on the number and geometry of the MNP sources inside the body. MRX tomography represents a novel approach for quantitative 3D imaging of MNPs, where the inverse solution is stabilized by a series of MRX measurements. In MRX tomography, only parts of the MNP distribution are sequentially magnetized by the use of inhomogeneous magnetic fields. Each magnetizing is followed by detection of the response of the corresponding part of the distribution by multiple sensors. The 3D reconstruction of the MNP distribution is then accomplished by a common evaluation of the distinct MRX measurement series. In this thesis the first experimental setup for MRX tomography was developed for quantitative 3D imaging of biomedical MNP distributions. It is based on a multi-channel magnetizing unit which has been engineered to

  3. Enhancement of the high-magnetic-field critical current density of superconducting MgB2 by proton irradiation.

    Science.gov (United States)

    Bugoslavsky, Y; Cohen, L F; Perkins, G K; Polichetti, M; Tate, T J; Gwilliam, R; Caplin, A D

    2001-05-31

    Magnesium diboride, MgB2, has a relatively high superconducting transition temperature, placing it between the families of low- and high-temperature (copper oxide based) superconductors. Supercurrent flow in MgB2 is unhindered by grain boundaries, making it potentially attractive for technological applications in the temperature range 20-30 K. But in the bulk material, the critical current density (Jc) drops rapidly with increasing magnetic field strength. The magnitude and field dependence of the critical current are related to the presence of structural defects that can 'pin' the quantized magnetic vortices that permeate the material, and a lack of natural defects in MgB2 may be responsible for the rapid decline of Jc with increasing field strength. Here we show that modest levels of atomic disorder induced by proton irradiation enhance the pinning of vortices, thereby significantly increasing Jc at high field strengths. We anticipate that either chemical doping or mechanical processing should generate similar levels of disorder, and so achieve performance that is technologically attractive in an economically viable way.

  4. Precision measurement of the proton and helium flux in primary cosmic rays with the Alpha Magnetic Spectrometer on the International Space Station

    Science.gov (United States)

    Heil, M.

    2016-11-01

    The precise measurements of the proton and helium flux in primary cosmic rays based on on data collected by the Alpha Magnetic Spectrometer during the first 30 months of operation (May 19, 2012 to November 26, 2013) onboard the International Space Station are presented. Knowledge of the rigidity dependence of the proton and helium flux is important in understanding the origin, acceleration, and propagation of cosmic rays in our galaxy. The high statistics of the measurements (300 mio. protons, 50 mio. helium) allow to study the detailed variations with rigidity of the fluxes spectral index. The spectral index of both the proton and the helium flux progressively hardens at rigidities larger than 100 GV. The rigidity dependence of the helium flux spectral index is similar to that of the proton spectral index though the magnitudes are different. Remarkably, the spectral index of the proton to helium flux ratio increases with rigidity up to 45 GV and then becomes constant; the flux ratio above 45 GV is well described by a single power law.

  5. High resolution NMR study of T{sub 1} magnetic relaxation dispersion. IV. Proton relaxation in amino acids and Met-enkephalin pentapeptide

    Energy Technology Data Exchange (ETDEWEB)

    Pravdivtsev, Andrey N.; Yurkovskaya, Alexandra V.; Ivanov, Konstantin L., E-mail: ivanov@tomo.nsc.ru [International Tomography Center, Institutskaya 3a, Novosibirsk 630090 (Russian Federation); Department of Physics, Novosibirsk State University, Pirogova 2, Novosibirsk 630090 (Russian Federation); Vieth, Hans-Martin [Institut für Experimentalphysik, Freie Universität Berlin Arnimallee 14, 14195 Berlin (Germany)

    2014-10-21

    Nuclear Magnetic Relaxation Dispersion (NMRD) of protons was studied in the pentapeptide Met-enkephalin and the amino acids, which constitute it. Experiments were run by using high-resolution Nuclear Magnetic Resonance (NMR) in combination with fast field-cycling, thus enabling measuring NMRD curves for all individual protons. As in earlier works, Papers I–III, pronounced effects of intramolecular scalar spin-spin interactions, J-couplings, on spin relaxation were found. Notably, at low fields J-couplings tend to equalize the apparent relaxation rates within networks of coupled protons. In Met-enkephalin, in contrast to the free amino acids, there is a sharp increase in the proton T{sub 1}-relaxation times at high fields due to the changes in the regime of molecular motion. The experimental data are in good agreement with theory. From modelling the relaxation experiments we were able to determine motional correlation times of different residues in Met-enkephalin with atomic resolution. This allows us to draw conclusions about preferential conformation of the pentapeptide in solution, which is also in agreement with data from two-dimensional NMR experiments (rotating frame Overhauser effect spectroscopy). Altogether, our study demonstrates that high-resolution NMR studies of magnetic field-dependent relaxation allow one to probe molecular mobility in biomolecules with atomic resolution.

  6. Noninvasive quantitation of human liver steatosis using magnetic resonance and bioassay methods

    Energy Technology Data Exchange (ETDEWEB)

    D' Assignies, Gaspard; Ruel, Martin; Khiat, Abdesslem; Lepanto, Luigi; Kauffmann, Claude; Tang, An [Centre Hospitalier de l' Universite de Montreal (CHUM), Departement de Radiologie, Montreal, Quebec (Canada); Chagnon, Miguel [Universite de Montreal (UDEM), Departement de Mathematiques et de Statistique, Montreal, Quebec (Canada); Gaboury, Louis [Centre Hospitalier de l' Universite de Montreal (CHUM), Departement d' Anatomo-Pathologie, Montreal, Quebec (Canada); Boulanger, Yvan [Centre Hospitalier de l' Universite de Montreal (CHUM), Departement de Radiologie, Montreal, Quebec (Canada); Hopital Saint-Luc du CHUM, Departement de Radiologie, Montreal, Quebec (Canada)

    2009-08-15

    The purpose was to evaluate the ability of three magnetic resonance (MR) techniques to detect liver steatosis and to determine which noninvasive technique (MR, bioassays) or combination of techniques is optimal for the quantification of hepatic fat using histopathology as a reference. Twenty patients with histopathologically proven steatosis and 24 control subjects underwent single-voxel proton MR spectroscopy (MRS; 3 voxels), dual-echo in phase/out of phase MR imaging (DEI) and diffusion-weighted MR imaging (DWI) examinations of the liver. Blood or urine bioassays were also performed for steatosis patients. Both MRS and DEI data allowed to detect steatosis with a high sensitivity (0.95 for MRS; 1 for DEI) and specificity (1 for MRS; 0.875 for DEI) but not DWI. Strong correlations were found between fat fraction (FF) measured by MRS, DEI and histopathology segmentation as well as with low density lipoprotein (LDL) and cholesterol concentrations. A Bland-Altman analysis showed a good agreement between the FF measured by MRS and DEI. Partial correlation analyses failed to improve the correlation with segmentation FF when MRS or DEI data were combined with bioassay results. Therefore, FF from MRS or DEI appear to be the best parameters to both detect steatosis and accurately quantify fat liver noninvasively. (orig.)

  7. Quantitative x-ray magnetic circular dichroism mapping with high spatial resolution full-field magnetic transmission soft x-ray spectro-microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, MacCallum J. [Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Physics Department, University of California, Berkeley, California 94720 (United States); Agostino, Christopher J. [Physics Department, University of California, Berkeley, California 94720 (United States); National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); N' Diaye, Alpha T. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Chen, Gong [National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Im, Mi-Young [Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology, Daegu 711-873 (Korea, Republic of); Fischer, Peter, E-mail: PJFischer@lbl.gov [Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Physics Department, University of California, Santa Cruz, California 94056 (United States)

    2015-05-07

    The spectroscopic analysis of X-ray magnetic circular dichroism (XMCD), which serves as strong and element-specific magnetic contrast in full-field magnetic transmission soft x-ray microscopy, is shown to provide information on the local distribution of spin (S) and orbital (L) magnetic moments down to a spatial resolution of 25 nm limited by the x-ray optics used in the x-ray microscope. The spatially resolved L/S ratio observed in a multilayered (Co 0.3 nm/Pt 0.5 nm) × 30 thin film exhibiting a strong perpendicular magnetic anisotropy decreases significantly in the vicinity of domain walls, indicating a non-uniform spin configuration in the vertical profile of a domain wall across the thin film. Quantitative XMCD mapping with x-ray spectro-microscopy will become an important characterization tool for systems with topological or engineered magnetization inhomogeneities.

  8. Hydrogen bonding study of quinoline and coal-derived asphaltene components with o-phenylphenol by proton magnetic resonance. [9 references

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, S.R.; Galya, L.G.; Brown, B.J.; Li, N.C.

    1976-01-01

    Proton magnetic resonance (PMR) studies are reported of hydrogen bonding between the OH proton of o-phenylphenol (OPP) and the nitrogen electron donor of quinoline (Qu). Data are also reported on the hydrogen bonding of a coal-derived asphaltene and its acid and base components with OPP. Determination was made of the equilibrium constants of the 1 : 1 complex between OPP and Qu at 39, 32, 1, and -18/sup 0/C from the PMR studies. Qualitative results are reported for the interaction between the base fraction of asphaltene and OPP at 32, 1, and -26/sup 0/C.

  9. Hydrogen bonding study of quinoline and coal-derived asphaltene components with o-phenylphenol by proton magnetic resonance. [9 refs

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, S.C.; Galya, L.G.; Brown, B.J.; Li, N.C.

    1976-01-01

    Proton magnetic resonance (PMR) studies are reported of hydrogen bonding between the OH proton of o-phenylphenol (OPP) and the nitrogen electron donor of quinoline (Qu). Data are also reported on the hydrogen bonding of a coal-derived asphaltene and its acid and base components with OPP. Determination was made of the equilibrium constants of the 1:1 complex between OPP and Qu at 39, 32, 1, and -18/sup 0/C from the PMR studies. Qualitative results are reported for the interaction between the base fraction of asphaltene and OPP at 32, 1, and -26/sup 0/C.

  10. Effects of acupuncture therapy on abdominal fat and hepatic fat content in obese children: a magnetic resonance imaging and proton magnetic resonance spectroscopy study.

    Science.gov (United States)

    Zhang, Hong; Peng, Yun; Liu, ZuXiang; Li, Shilian; Lv, Zhongli; Tian, LiFang; Zhu, Jie; Zhao, XuNa; Chen, Min

    2011-05-01

    The aim of this study was to use magnetic resonance imaging (MRI) together with proton magnetic resonance spectroscopy ((1)H-MRS) to study the influence of acupuncture therapy on abdominal fat and hepatic fat content in obese children. The design was a longitudinal, clinical intervention study of acupuncture therapy. SUBJECTS were 10 healthy, obese children (age: 11.4 ± 1.65 years, body-mass index [BMI]: 29.03 ± 4.81 kg/m(2)). Measurements included various anthropometric parameters, abdominal fat (assessed by MRI) and hepatic fat content (assessed by (1)H-MRS) at baseline and after 1 month of acupuncture therapy. One (1) month of acupuncture therapy significantly reduced the subjects' BMI by 3.5% (p = 0.005), abdominal visceral adipose tissue (VAT) volume by 16.04% (p  0.05). There was a significant correlation between the level of abdominal fat (SAT, VAT) and anthropometric parameters (weight, BMI, waist circumferences, hip circumferences). There was no statistically significant correlation between IHTG and anthropometric parameters or abdominal fat content. The first direct experimental evidence is provided demonstrating that acupuncture therapy significantly reduces BMI and abdominal adipose tissue by reducing abdominal VAT content without significant changes in body weight, waist circumference, hip circumference, WHR, abdominal SAT, or IHTG content. Thus, the use of acupuncture therapy to selectively target a reduction in abdominal VAT content should become more important and more popular in the future.

  11. Maturation of limbic regions in Asperger syndrome: a preliminary study using proton magnetic resonance spectroscopy and structural magnetic resonance imaging.

    Science.gov (United States)

    O'Brien, Finian M; Page, Lisa; O'Gorman, Ruth L; Bolton, Patrick; Sharma, Ajay; Baird, Gillian; Daly, Eileen; Hallahan, Brian; Conroy, Ronán M; Foy, Catherine; Curran, Sarah; Robertson, Dene; Murphy, Kieran C; Murphy, Declan G M

    2010-11-30

    People with autistic spectrum disorders (ASD, including Asperger syndrome) may have developmental abnormalities in the amygdala-hippocampal complex (AHC). However, in vivo, age-related comparisons of both volume and neuronal integrity of the AHC have not yet been carried out in people with Asperger syndrome (AS) versus controls. We compared structure and metabolic activity of the right AHC of 22 individuals with AS and 22 healthy controls aged 10-50 years and examined the effects of age between groups. We used structural magnetic resonance imaging (sMRI) to measure the volume of the AHC, and magnetic resonance spectroscopy ((1)H-MRS) to measure concentrations of N-acetyl aspartate (NAA), creatine+phosphocreatine (Cr+PCr), myo-inositol (mI) and choline (Cho). The bulk volume of the amygdala and the hippocampus did not differ significantly between groups, but there was a significant difference in the effect of age on the hippocampus in controls. Compared with controls, young (but not older) people with AS had a significantly higher AHC concentration of NAA and a significantly higher NAA/Cr ratio. People with AS, but not controls, had a significant age-related reduction in NAA and the NAA/Cr ratio. Also, in people with AS, but not controls, there was a significant relationship between concentrations of choline and age so that choline concentrations reduced with age. We therefore suggest that people with AS have significant differences in neuronal and lipid membrane integrity and maturation of the AHC.

  12. Uveal melanoma: quantitative evaluation of diffusion-weighted MR imaging in the response assessment after proton-beam therapy, long-term follow-up.

    Science.gov (United States)

    Foti, Pietro Valerio; Longo, Antonio; Reibaldi, Michele; Russo, Andrea; Privitera, Giuseppe; Spatola, Corrado; Raffaele, Luigi; Salamone, Vincenzo; Farina, Renato; Palmucci, Stefano; Musumeci, Andrea; Caltabiano, Rosario; Ragusa, Marco; Mariotti, Cesare; Avitabile, Teresio; Milone, Pietro; Ettorre, Giovanni Carlo

    2017-02-01

    The purpose of this prospective study was to investigate the proton-beam-induced changes in apparent diffusion coefficient (ADC) values of ocular melanoma treated with proton-beam therapy (PBT) in patients undergoing long-term magnetic resonance imaging (MRI) follow-up and to assess whether variations in ADC constitute a reliable biomarker for predicting and detecting the response of ocular melanoma to PBT. Seventeen patients with ocular melanoma treated with PBT were enrolled. All patients underwent conventional MRI and diffusion-weighted imaging (DWI) at baseline and 1, 3, 6, and 18 months after the beginning of therapy. Tumor volumes and ADC values of ocular lesions were measured at each examination. Tumor volumes and mean ADC measurements of the five examination series were compared; correlation of ADC values and tumor regression was estimated. Mean ADC values of ocular melanomas significantly increased already 1 month after therapy whereas tumor volume significantly decreased only 6 months after therapy. Pretreatment ADC value of ocular melanomas and early change in ADC value 1 month after therapy significantly correlated with tumor regression. In ocular melanoma treated with PBT, ADC variations precede volume changes. Both pretreatment ADC and early change in ADC value may predict treatment response, thus expanding the role of DWI from diagnostic to prognostic.

  13. A quantitative comparison of the TERA modeling and DFT magnetic resonance image reconstruction techniques.

    Science.gov (United States)

    Smith, M R; Nichols, S T; Constable, R T; Henkelman, R M

    1991-05-01

    The resolution of magnetic resonance images reconstructed using the discrete Fourier transform (DFT) algorithm is limited by the effective window generated by the finite data length. The transient error reconstruction approach (TERA) is an alternative reconstruction method based on autoregressive moving average (ARMA) modeling techniques. Quantitative measurements comparing the truncation artifacts present during DFT and TERA image reconstruction show that the modeling method substantially reduces these artifacts on "full" (256 X 256), "truncated" (256 X 192), and "severely truncated" (256 X 128) data sets without introducing the global amplitude distortion found in other modeling techniques. Two global measures for determining the success of modeling are suggested. Problem areas for one-dimensional modeling are examined and reasons for considering two-dimensional modeling discussed. Analysis of both medical and phantom data reconstructions are presented.

  14. Quantitative magnetic resonance imaging and studies of degenerative diseases of the developing human brain

    Energy Technology Data Exchange (ETDEWEB)

    Caviness, V.S. Jr. (Massachusetts General Hospital, Boston, MA (United States)); Phil, D.; Filipek, P.A.; Kennedy, D.N.

    1992-05-01

    The Rett syndrome is a progressive disorder which is associated with regression of psychomotor development and precipitous deceleration of brain growth during the first year of life. General histopathological surveys in postmortem specimens have identified degeneration of subpopulations of neurons of the nigrostriatal system but no other evidence of degenerative process. Magnetic resonance imaging-based morphometry may usefully guide application of rigorous but demanding quantitative histologic search for evidence of neuronal degeneration. The volumes of the principal set of cortical and nuclear structures of principal interest in the disorder may be measured by currently avaiable MRI-based methods. Opimized levels of precision now allow detection of volumetric changes over time in the same brain of approximately 10% at the 95% confidence level. (author).

  15. Quantitative determination Of etimicin sulfate by nuclear magnetic resonance%核磁共振法测定硫酸依替米星含量

    Institute of Scientific and Technical Information of China (English)

    于小波; 相秉仁; 王国华; 宋喆; 沈文斌

    2011-01-01

    Qualitative and quantitative analysis of etimicin sulfate were reported by nuclear magnetic resonance(NMR).The 1H-NMR and 13C-NMR spectra of etimicin sulfate have been assigned by means of 1D and 2D spectroscopy including DEPT, COSY, HSQC and HMBC.On the basis of assignment, a novel approach was developed for the determination of purity of etimicin sulfate by proton-nuclear magnetic resonance (1H-NMR)using p-hydroquinone as internal standard.The result showed that the purity of etimicin was 59.19%, and its relative standard deviations(RSD) was 0.24%, this method was relative accuracy, precision, and ease of application.%通过核磁共振法对硫酸依替米星进行定性和定量分析.利用一维及二维核磁共振谱(DEPT、COSY、HSQC、HMBC),对H-NMR谱和C-NMR谱信号进行完整归属.在此基础上,采用氢核磁共振定量法,以对苯二酚为内标,测得硫酸依替米星中依替米星的含量为59.19%,RSD为0.24%,方法准确可靠,简便快速.

  16. The alpha magnetic spectrometer silicon tracker: Performance results with protons and helium nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Alcaraz, J. [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (CIEMAT), E-28040 Madrid (Spain); Alpat, B.; Ambrosi, G. [INFN Sezione di Perugia and Universita degli Studi di Perugia, I-06100 Perugia (Italy); Azzarello, Ph. [Universite de Geneve, CH-1211, Geneve 4 (Switzerland); Battiston, R.; Bertucci, B. [INFN Sezione di Perugia and Universita degli Studi di Perugia, I-06100 Perugia (Italy); Bolmont, J. [Laboratoire de Physique Theorique et Astroparticules, IN2P3/CNRS, Universite de Montpellier II, F-34095 Montpellier (France); Bourquin, M. [Universite de Geneve, CH-1211, Geneve 4 (Switzerland); Burger, W.J. [INFN Sezione di Perugia and Universita degli Studi di Perugia, I-06100 Perugia (Italy)], E-mail: william.burger@cern.ch; Capell, M. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Cardano, F. [INFN Sezione di Perugia and Universita degli Studi di Perugia, I-06100 Perugia (Italy); Chang, Y.H. [National Central University, Jhungli 320, Taiwan (China); Choutko, V. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Cortina, E. [Universite de Geneve, CH-1211, Geneve 4 (Switzerland); Dinu, N. [Institute for Space Science (ISS), R-76900 Bucharest (Romania); Esposito, G.; Fiandrini, E. [INFN Sezione di Perugia and Universita degli Studi di Perugia, I-06100 Perugia (Italy); Haas, D. [Universite de Geneve, CH-1211, Geneve 4 (Switzerland); Haino, S. [INFN Sezione di Perugia and Universita degli Studi di Perugia, I-06100 Perugia (Italy); Hakobyan, H. [Universite de Geneve, CH-1211, Geneve 4 (Switzerland)] (and others)

    2008-08-11

    The Alpha Magnetic Spectrometer is designed for a long duration measurement of the cosmic-ray spectra at an altitude of 400 km. The particle rigidity and specific energy loss are measured by a silicon tracker located in a 0.8 T field. Ground results for the position resolution, detection efficiency and charge determination for singly and doubly charged relativistic particles are presented and discussed in the context of the spaceborne detector.

  17. USE OF PROTON MAGNETIC RESONANCE SPECTROSCOPIC IMAGING DATA IN PLANNING FOCAL RADIATION THERAPIES FOR BRAIN TUMORS

    Directory of Open Access Journals (Sweden)

    Edward E Graves

    2011-05-01

    Full Text Available Advances in radiation therapy for malignant neoplasms have produced techniques such as Gamma Knife radiosurgery, capable of delivering an ablative dose to a specific, irregular volume of tissue. However, efficient use of these techniques requires the identification of a target volume that will produce the best therapeutic response while sparing surrounding normal brain tissue. Accomplishing this task using conventional computed tomography (CT and contrast-enhanced magnetic resonance imaging (MRI techniques has proven difficult because of the difficulties in identifying the effective tumor margin. Magnetic resonance spectroscopic imaging (MRSI has been shown to offer a clinically-feasible metabolic assessment of the presence and extent of neoplasm that can complement conventional anatomic imaging. This paper reviews current Gamma Knife protocols and MRSI acquisition, reconstruction, and interpretation techniques, and discusses the motivation for including magnetic resonance spectroscopy findings while planning focal radiation therapies. A treatment selection and planning strategy incorporating MRSI is then proposed, which can be used in the future to assess the efficacy of spectroscopy-based therapy planning.

  18. Assessment of Proton Microbeam Analysis of 11B for Quantitative Microdistribution Analysis of Boronated Neutron Capture Agent Analogs in Biological Tissues

    Energy Technology Data Exchange (ETDEWEB)

    Bench, G; Grant, P G; Ueda, D L; Autry-Conwell, S A; Hou, Y; Boggan, J E

    2002-12-04

    Purpose: To assess the {sup 11}B(p, {alpha}){sup 8}Be* nuclear reaction for quantitatively mapping the in-vivo sub-cellular distribution of boron within gliosarcoma tumors treated with boronated neutron capture therapy agent (NCTA) analogs. Materials and Methods: Intracranial tumors were produced in Fisher 344 rats using a 9L gliosarcoma model. Fourteen days later, the majority of rats were treated with f-boronophenylalanine and sacrificed 30 or 180 minutes after intravenous injection. Freeze dried tumor cryosections were imaged using the {sup 11}B(p, {alpha}){sup 8}Be* nuclear reaction and proton microbeams obtained from the nuclear microprobe at Lawrence Livermore National Laboratory. Results/Discussion: With{sup 11}B(p, {alpha}){sup 8}Be* analysis, {sup 11}B distributions within cells can be quantitatively imaged with spatial resolutions down to 1.5 {micro}m, minimum detection limits of 0.8 mg/kg and acquisition times of several hours. These capabilities offer advantages over alpha track autoradiography, electron energy loss spectroscopy and secondary ion mass spectrometry (SIMS) for 'B quantitation in tissues. However, the spatial resolution, multi-isotope capability and analysis times achieved with SIMS are superior to those achieved with {sup 11}B(p, {alpha}){sup 8}Be* analysis. Conclusions: When accuracy in quantitation is crucial, the assessing the microdistribution of {sup 11}B. {sup 11}B(p, {alpha}){sup 8}Be* reaction is well suited for Otherwise, SIMS may well be better suited to image the microdistribution of boron associated with NCTAs in biological tissues.

  19. Quantitative criteria for the diagnosis of the congenital absence of pericardium by cardiac magnetic resonance.

    Science.gov (United States)

    Macaione, F; Barison, A; Pescetelli, I; Pali, F; Pizzino, F; Terrizzi, A; Di Lisi, D; Novo, G; Todiere, G; Assennato, P; Novo, S; Aquaro, G D

    2016-03-01

    Congenital absence of the left ventricular pericardium (LCAP) is a rare and poorly known cardiac malformation. Cardiac Magnetic Resonance (CMR) is generally used for the diagnosis of LCAP because of its high soft tissue contrast, multiplanarity and cine capability, but the diagnosis is usually made by only qualitative criteria. The aim of the present study was to establish quantitative criteria for the accurate diagnosis of LCAP on CMR. We enrolled nine consecutive patients affected by LCAP (mean age 26±8years, 7 males), 13 healthy controls, 13 patients with dilated cardiomyopathy (DCM), 12 patients with hypertrophic cardiomyopathy (HCM) and 13 patients with right ventricular overload (RVO). All patients underwent CMR. The whole-heart volume was measured in end-systole and end-diastole. Whole-heart volume change (WHVC), was the systo-diastolic change of volume, expressed percentage of the end-diastolic volume. The angle of clockwise-rotation of the heart was also measured in the end-diastolic phase of the axial cine stack. The WHVC was significantly higher in LCAP (21.9±5.4), compared to healthy subjects (8.6±2.4, p13%. In LCAP the systo-diastolic WHVC was significantly higher than controls, DCM, HCM and RVO patients and resulted an optimal quantitative criteria for the diagnosis of LCAP. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  20. Quantitative evaluation of diffusion-weighted magnetic resonance imaging of focal hepatic lesions

    Institute of Scientific and Technical Information of China (English)

    Xi-Jie Sun; Xian-Yue Quan; Fan-Heng Huang; Yi-Kai Xu

    2005-01-01

    AIM: To explore the quantitative analysis of diffusionweighted magnetic resonance imaging (DWMRI) in differential diagnosis of focal hepatic lesions.METHODS: DWMRI was performed in 149 hepatic lesions, including hepatocellular carcinoma (34 cases),hepatic metastases (37 cases), cavernous hemangioma (42 cases), hepatic cyst (36 cases). Apparent diffusion coefficient (ADC) values were evaluated using four different b values in different sequences. The ratio of ADC values of lesion/liver in hepatocellular carcinoma and hepatic metastases was also calculated.RESULTS: The mean ADC values of hepatic lesions were as follows: hepatocellular carcinoma (0.95 ± 0.11) × 10-3 mm2/s, hepatic metastasis (1.13 ± 0.21)× 10-3 mm2/s, cavernous hemangioma (1.86±0.36)×10-3 mm2/s,hepatic cyst(3.14±0.31)×10-3 mm2/s. The ratio of ADC values in lesion/liver in hepatocellular carcinoma was 0.91 ±0.11, being significantly different from that in hepatic metastasis (1.21 ± 0.18, P< 0.05).CONCLUSION: ADC values and quantitative analysis of focal hepatic lesions are of significant values in differential diagnosis of focal hepatic lesions.

  1. Study on hippocampal volume with quantitative 3T magnetic resonance imaging in Chinese patients with epilepsy

    Institute of Scientific and Technical Information of China (English)

    GAO Mei-chun; LU Qin-chi; LI Yan-sheng; SHEN Jia-lin

    2012-01-01

    Background It was still rare for the quantitative magnetic resonance imaging (MRI) research of regional changes in hippocampus sclerosis (HS) in Chinese patients with epilepsy.This study aimed to study the hippocampal volumes (HVs)with quantitative MRI measurement in Chinese patients with epilepsy.Methods Forty-six Chinese patients with epilepsy (intractable epilepsy (IE),n=21; non-intractable epilepsy (NIE),n=25)and 25 normal controls were collected between July 2007 and March 2008.All of the subjects underwent a 3T high-resolution MRI with oblique coronal thin sections oriented perpendicular to the hippocampal long axis.Hippocampal structures were assessed by visual detection,and HVs were quantitatively studied with a Picture Archiving and Communication System (PACS).Results Our study suggested that there was no significant difference in gender (P >0.05) while the right hippocampal head volume (HHV),hippocampal body volume (HBV),and the whole hippocampal volume (HCV) were greater than the left one (P <0.05),but no significant difference was found in bilateral hippocampal tail volume (HTV) (P >0.05) in normal controls.That unilateral/diffuse (64%/21%) and bilateral/focal (86%/20%) hippocampal atrophy (HA)were significant in IE and NIE patients,respectively.Anterior hippocampus,especially HHV (26% in IE and 20% in NIE) and HBV (29% in IE and 12% in NIE),had more significant atrophy than the HTV (5% in IE and 0% in NIE) in patients with epilepsy.Conclusion By assessing the volumes of the regional hippocampus with 3T MRI,we could better define the range and distribution of HS,since regional or subtle changes in HVs could be detected earlier with 3T MRI.

  2. Insula-specific responses induced by dental pain. A proton magnetic resonance spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Gutzeit, A.; Weymarn, C. von; Froehlich, J.M.; Binkert, C.A. [Cantonal Hospital Winterthur, Department of Radiology, Winterthur (Switzerland); Meier, D. [University and ETH Zurich, Institute for Biomedical Engineering, Zurich (Switzerland); Meier, M.L.; Bruegger, M. [University of Zurich, Institute of Psychology, Division Neuropsychology, Zurich (Switzerland); Ettlin, D.A. [University of Zuerich, Center for Dental and Oral Medicine and Cranio-Maxillofacial Surgery, Clinic for Removable Prosthodontics, Masticatory Disorders and Special Care Dentistry, Zuerich (Switzerland); Graf, N. [University Hospital of Zurich, Clinical Trials Center, Center for Clinical Research, Zurich (Switzerland)

    2011-04-15

    To evaluate whether induced dental pain leads to quantitative changes in brain metabolites within the left insular cortex after stimulation of the right maxillary canine and to examine whether these metabolic changes and the subjective pain intensity perception correlate. Ten male volunteers were included in the pain group and compared with a control group of 10 other healthy volunteers. The pain group received a total of 87-92 electrically induced pain stimuli over 15 min to the right maxillary canine tooth. Contemporaneously, they evaluated the subjective pain intensity of every stimulus using an analogue scale. Neurotransmitter changes within the left insular cortex were evaluated by MR spectroscopy. Significant metabolic changes in glutamine (+55.1%), glutamine/glutamate (+16.4%) and myo-inositol (-9.7%) were documented during pain stimulation. Furthermore, there was a significant negative correlation between the subjective pain intensity perception and the metabolic levels of Glx, Gln, glutamate and N-acetyl aspartate. The insular cortex is a metabolically active region in the processing of acute dental pain. Induced dental pain leads to quantitative changes in brain metabolites within the left insular cortex resulting in significant alterations in metabolites. Negative correlation between subjective pain intensity rating and specific metabolites could be observed. (orig.)

  3. Nonlinear Alfvén waves, discontinuities, proton perpendicular acceleration, and magnetic holes/decreases in interplanetary space and the magnetosphere: intermediate shocks?

    Directory of Open Access Journals (Sweden)

    B. T. Tsurutani

    2005-01-01

    Full Text Available Alfvén waves, discontinuities, proton perpendicular acceleration and magnetic decreases (MDs in interplanetary space are shown to be interrelated. Discontinuities are the phase-steepened edges of Alfvén waves. Magnetic decreases are caused by a diamagnetic effect from perpendicularly accelerated (to the magnetic field protons. The ion acceleration is associated with the dissipation of phase-steepened Alfvén waves, presumably through the Ponderomotive Force. Proton perpendicular heating, through instabilities, lead to the generation of both proton cyclotron waves and mirror mode structures. Electromagnetic and electrostatic electron waves are detected as well. The Alfvén waves are thus found to be both dispersive and dissipative, conditions indicting that they may be intermediate shocks. The resultant 'turbulence' created by the Alfvén wave dissipation is quite complex. There are both propagating (waves and nonpropagating (mirror mode structures and MDs byproducts. Arguments are presented to indicate that similar processes associated with Alfvén waves are occurring in the magnetosphere. In the magnetosphere, the 'turbulence' is even further complicated by the damping of obliquely propagating proton cyclotron waves and the formation of electron holes, a form of solitary waves. Interplanetary Alfvén waves are shown to rapidly phase-steepen at a distance of 1AU from the Sun. A steepening rate of ~35 times per wavelength is indicated by Cluster-ACE measurements. Interplanetary (reverse shock compression of Alfvén waves is noted to cause the rapid formation of MDs on the sunward side of corotating interaction regions (CIRs. Although much has been learned about the Alfvén wave phase-steepening processfrom space plasma observations, many facets are still not understood. Several of these topics are discussed for the interested researcher. Computer simulations and theoretical developments will be particularly useful in making further progress in

  4. Quantitative T1 and proton density mapping with direct calculation of radiofrequency coil transmit and receive profiles from two-point variable flip angle data.

    Science.gov (United States)

    Baudrexel, Simon; Reitz, Sarah C; Hof, Stephanie; Gracien, René-Maxime; Fleischer, Vinzenz; Zimmermann, Hilga; Droby, Amgad; Klein, Johannes C; Deichmann, Ralf

    2016-03-01

    Quantitative T1 mapping of brain tissue is frequently based on the variable flip angle (VFA) method, acquiring spoiled gradient echo (GE) datasets at different excitation angles. However, accurate T1 calculation requires a knowledge of the sensitivity profile B1 of the radiofrequency (RF) transmit coil. For an additional derivation of proton density (PD) maps, the receive coil sensitivity profile (RP) must also be known. Mapping of B1 and RP increases the experiment duration, which may be critical when investigating patients. In this work, a method is presented for the direct calculation of B1 and RP from VFA data. Thus, quantitative maps of T1 , PD, B1 and RP can be obtained from only two spoiled GE datasets. The method is based on: (1) the exploitation of the linear relationship between 1/PD and 1/T1 in brain tissue and (2) the assumption of smoothly varying B1 and RP, so that a large number of data points can be fitted across small volume elements where B1 and RP are approximately constant. The method is tested and optimized on healthy subjects. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  5. Improved measurement of labile proton concentration-weighted chemical exchange rate (kws) with experimental factor-compensated and T1-normalized quantitative chemical exchange saturation transfer (CEST) MRI

    Science.gov (United States)

    Wu, Renhua; Liu, Charng-Ming; Liu, Philip K; Sun, Phillip Zhe

    2012-01-01

    Chemical exchange saturation transfer (CEST) MRI enables measurement of dilute CEST agents and microenvironment properties such as pH and temperature, holding great promise for in vivo applications. However, because of confounding concomitant RF irradiation and relaxation effects, the CEST-weighted MRI contrast may not fully characterize the underlying CEST phenomenon. We postulated that the accuracy of quantitative CEST MRI could be improved if the experimental factors (labeling efficiency and RF spillover effect) were estimated and taken into account. Specifically, the experimental factor was evaluated as a function of exchange rate and CEST agent concentration ratio, which remained relatively constant for intermediate RF irradiation power levels. Hence, the experimental factors can be calculated based on the reasonably estimated exchange rate and labile proton concentration ratio, which significantly improved quantification. The simulation was confirmed with Creatine phantoms of serially varied concentration titrated to the same pH, whose reverse exchange rate (kws) was found to be linearly correlated with the concentration. In summary, the proposed solution provides simplified yet reasonably accurate quantification of the underlying CEST system, which may help guide the ongoing development of quantitative CEST MRI. PMID:22649044

  6. Cerebral proton magnetic resonance spectroscopy demonstrates reversibility of N-acetylaspartate/creatine in gray matter after delayed encephalopathy due to carbon monoxide intoxication

    DEFF Research Database (Denmark)

    Hansen, Marco Bo; Kondziella, Daniel; Danielsen, Else Rubæk

    2014-01-01

    with cerebral proton magnetic resonance spectroscopy showed a dramatically decrease in N-acetylaspartate to total creatine ratios and elevated lactate levels in the gray matter. Subsequently, our patient received six additional sessions of hyperbaric oxygen therapy with only minimal recovery. At six...... in mid-occipital gray matter and partial reversal in white matter. CONCLUSIONS: The present case indicates that cerebral proton magnetic spectroscopy provides valuable information on brain metabolism in patients presenting with delayed encephalopathy after acute carbon monoxide intoxication. The full...... reversal of N-acetylaspartate to total creatine ratios in gray matter has, to our knowledge, never been described before and shows that severe, initial measurements may not predict poor long-term patient outcome....

  7. Associated electron and proton transfer between Acridine and Triethylamine in AOT reverse micelles probed by laser flash photolysis with magnetic field

    Science.gov (United States)

    Sarangi, Manas Kumar; Basu, Samita

    2011-04-01

    Laser flash photolysis with magnetic field (MF ˜0.08 T) has been used to study interaction between Acridine (Acr) and Triethylamine (TEA) in reverse micelles with w0 = 2.5-40. Dynamic protonation equilibrium exists between 3Acr and 3AcrH +. The intermediates indicate excited-state proton transfer (PT) between 3AcrH + and TEA. However, application of MF highlights the formation of geminate radical ion pairs (RIPs) with triplet spin-correlation, a signature of latent photoinduced electron transfer between 3AcrH + and TEA co-exists with PT. Magnetic field effect (MFE) is prominent for smaller w0 showing importance of optimum separation between RIP to maximize MFE, whereas PT remains unaltered.

  8. Proton magnetic resonance spectroscopy ((1H-MRS reveals geniculocalcarine and striate area degeneration in primary glaucoma.

    Directory of Open Access Journals (Sweden)

    Yan Zhang

    Full Text Available BACKGROUND: Glaucoma is a collection of neurodegenerative diseases that affect both the retina and the central visual pathway. We investigated whether metabolites' concentrations changed in the geniculocalcarine (GCT and the striate area of occipital lobe by proton magnetic resonance spectroscopy ((1H-MRS, suggesting neurodegeneration of the central visual pathway in primary glaucoma. METHODOLOGY/PRINCIPAL FINDINGS: 20 patients with glaucoma in both eyes were paired with 20 healthy volunteers in same gender and an age difference less than 3 years. All the participants were examined by MR imaging including T1 Flair, T2 FSE and (1H-MRS. The T1 intensity and T2 intensity of their GCTs and striate areas were measured. The ratio of N-acetylaspartate (NAA/Creatine (Cr, Choline (Cho/Cr, glutamine and glutamate (Glx/Cr were derived by multi-voxels (1H-MRS in the GCT and the striate area of each brain hemisphere. The T1 intensity and T2 intensity had no difference between the groups. Significant decreases in NAA/Cr and Cho/Cr but no difference in Glx/Cr was found between the groups in both the GCT and the striate area. CONCLUSIONS/SIGNIFICANCE: Primary glaucoma affects metabolites' concentrations in the GCT and the striate area suggesting there is ongoing neurodegenerative process.

  9. Magnetic resonance spectroscopy study of proton metabolite level changes in sensorimotor cortex after upper limb replantation-revascularization.

    Science.gov (United States)

    Ertem, Kadir; Alkan, Alpay; Sarac, Kaya; Onal, Cagatay; Bostan, Haci; Yologlu, Saim; Bora, Arslan

    2005-01-01

    We aimed to investigate the changes in proton metabolite levels at the motor and somatosensory cortex by magnetic resonance spectroscopy (MRS) after upper extremity replantation or revascularization. Nine patients who referred to our clinic suffering from major total (two) and subtotal (seven) amputation of the upper extremity were enrolled in this study. Mean time value between the injury and operation was 5.1 h. Mean follow-up period or mean time between the injury and MRS analysis was 26.2 months (ranging from 7 to 41 months). Voxels (TR: 2000; TE: 136 ms) were placed onto locations in the bilateral precentral and postcentral cortex area of the cerebral hemispheres that represent the upper extremity. Contralateral sides of the brain hemisphere that represent the injured extremity were accounted as control groups. Metabolite ratios [NAA (N-acetyl aspartate)/Cr (creatine) and Cho (choline)/Cr] of the motor and somatosensory cortex were calculated. The NAA/Cr and Cho/Cr metabolite ratios between the two groups were found to be insignificant, and these results may indicate that there is no remarkable somatosensorial cortex disruption or demyelination in these patients. Fifty-six percent of patients were found as functional according to Chen's scale.

  10. Evaluation of neuron-glia integrity by in vivo proton magnetic resonance spectroscopy: Implications for psychiatric disorders.

    Science.gov (United States)

    Xu, Haiyun; Zhang, Handi; Zhang, Jie; Huang, Qingjun; Shen, Zhiwei; Wu, Renhua

    2016-12-01

    Proton magnetic resonance spectroscopy ((1)H-MRS) has been widely applied in human studies. There is now a large literature describing findings of brain MRS studies with mental disorder patients including schizophrenia, bipolar disorder, major depressive disorder, and anxiety disorders. However, the findings are mixed and cannot be reconciled by any of the existing interpretations. Here we proposed the new theory of neuron-glia integrity to explain the findings of brain (1)H-MRS stuies. It proposed the neurochemical correlates of neuron-astrocyte integrity and axon-myelin integrity on the basis of update of neurobiological knowledge about neuron-glia communication and of experimental MRS evidence for impairments in neuron-glia integrity from the authors and the other investigators. Following the neuron-glia integrity theories, this review collected evidence showing that glutamate/glutamine change is a good marker for impaired neuron-astrocyte integrity and that changes in N-acetylaspartate and lipid precursors reflect impaired myelination. Moreover, this new theory enables us to explain the differences between MRS findings in neuropsychiatric and neurodegenerative disorders. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. Proton nuclear magnetic resonance spectroscopic detection of oligomannosidic n glycans in alpha-mannosidosis: a method of monitoring treatment.

    Science.gov (United States)

    Avenarius, Derk Frederik Matthaus; Svendsen, John-Sigurd; Malm, Dag

    2011-10-01

    In Alpha-mannosidosis (MIM 248500) the patients accumulate mainly unbranched oligosaccharide chains in the lysosomes in all body tissues, including the brain. With ensuing therapeutic modalities in man (BMT and ERT) non-invasive methods of monitoring the effect of treatment are needed. Paramount is the possible effect of the treatment on the brain, since this organ is regarded as difficult to reach because of the blood-brain barrier. We therefore performed proton nuclear magnetic resonance spectroscopy (MRS) of the brain in two untreated patients, and a 16-year-old patient treated with BMT at the age of 10 to assess whether this non-invasive method could be applied in the monitoring of the accumulation of abnormal chemicals in the brain of patients. We found an abnormal peak that was not present in the treated patient. A similar pattern was also found in MRS of urine from patients, reflecting the concentration of oligosaccharides in serum and tissues. We therefore conclude that MRS can be a useful method to monitor the effect of treatment for Alpha-Mannosidosis.

  12. In vivo proton magnetic resonance spectroscopic imaging of the healthy human brain at 9.4 T: initial experience.

    Science.gov (United States)

    Chadzynski, Grzegorz L; Pohmann, Rolf; Shajan, Gunamony; Kolb, Rupert; Bisdas, Sotirios; Klose, Uwe; Scheffler, Klaus

    2015-06-01

    In this study, the feasibility of in vivo proton magnetic resonance spectroscopic imaging ((1)H MRSI) of the healthy human brain at a field strength of 9.4 T, using conventional acquisition techniques, is examined and the initial experience is summarized. MRSI measurements were performed on a 9.4 T MR scanner (Siemens, Erlangen, Germany) equipped with head-only gradient insert (AC84, Siemens) and custom-developed, 8-channel transmit/24-channel receive, and 16-channel transmit/31-channel receive coils. Spectra were acquired from the superior part of the human brain with a modified STEAM sequence. Spectral quantification was done with LCModel software. Reasonable quality and signal-to-noise ratio of the acquired spectra allowed reliable quantification of 12 metabolites (Cramer-Rao lower bounds < 20 %), some of which may be difficult to quantify at field strengths below 7 T due to overlapping resonances or low concentrations. While further developments are necessary to minimize chemical shift displacement and homogeneity of the transmit field, it is demonstrated that in vivo (1)H MRSI at a field strength of 9.4 T is possible. However, further studies applying up-to-date techniques to overcome high-field specific problems are needed in order to assess the potential gain in sensitivity that may be offered by MRSI at 9.4 T.

  13. In vivo proton magnetic resonance spectroscopy reveals region specific metabolic responses to SIV infection in the macaque brain

    Directory of Open Access Journals (Sweden)

    Joo Chan-Gyu

    2009-06-01

    Full Text Available Abstract Background In vivo proton magnetic resonance spectroscopy (1H-MRS studies of HIV-infected humans have demonstrated significant metabolic abnormalities that vary by brain region, but the causes are poorly understood. Metabolic changes in the frontal cortex, basal ganglia and white matter in 18 SIV-infected macaques were investigated using MRS during the first month of infection. Results Changes in the N-acetylaspartate (NAA, choline (Cho, myo-inositol (MI, creatine (Cr and glutamine/glutamate (Glx resonances were quantified both in absolute terms and relative to the creatine resonance. Most abnormalities were observed at the time of peak viremia, 2 weeks post infection (wpi. At that time point, significant decreases in NAA and NAA/Cr, reflecting neuronal injury, were observed only in the frontal cortex. Cr was significantly elevated only in the white matter. Changes in Cho and Cho/Cr were similar across the brain regions, increasing at 2 wpi, and falling below baseline levels at 4 wpi. MI and MI/Cr levels were increased across all brain regions. Conclusion These data best support the hypothesis that different brain regions have variable intrinsic vulnerabilities to neuronal injury caused by the AIDS virus.

  14. Detection of inflammatory bowel disease by proton magnetic resonance spectroscopy (1H MRS using an animal model

    Directory of Open Access Journals (Sweden)

    Dolenko Brion

    2007-11-01

    Full Text Available Abstract Background The aim of this study was to analyze the potential of proton magnetic resonance spectroscopy (1H MRS in diagnosing early inflammatory bowel disease (IBD. Methods Thirty male Sprague Dawley rats were fed 2% carrageenan in their diet for either 1 or 2 weeks. 1H MRS was performed ex-vivo on colonic mucosal samples (n = 123 and the spectra were analyzed by a multivariate method of analysis. The results of the multivariate analysis were correlated with histological analysis performed using H & E stain for the presence of inflammation in the samples from each group. Results Multivariate analysis classified the samples in their respective groups with an accuracy of 82%. Our region selection algorithm identified four regions in the spectra as being discriminatory. The metabolites assigned to these regions include creatine, phosphatidylcholine, the -CH2HC= group in fatty acyl chain, and the glycerol backbone of lipids. The differences in concentration of these metabolites in each group offer insight into the biochemical changes occurring during IBD and confer diagnostic potential to 1H MRS as a tool to study colonic inflammation in conjunction with biopsy. Conclusion 1H MRS is a sensitive tool to detect early colonic inflammation in an animal model of IBD.

  15. Diffusion tensor imaging and proton magnetic resonance spectroscopy in brain tumorCorrelation between structure and metabolism

    Institute of Scientific and Technical Information of China (English)

    Zhigang Min; Chen Niu; Netra Rana; Huanmei Ji; Ming Zhang

    2013-01-01

    Proton magnetic resonance spectroscopy and diffusion tensor imaging are non-invasive techniques used to detect metabolites and water diffusion in vivo. Previous studies have confirmed a positive correlation of individual fractional anisotropy values with N-acetylaspartate/creatine and N-acetylaspartate/choline ratios in tumors, edema, and normal white matter. This study divided the brain parenchyma into tumor, peritumoral edema, and normal-appearing white matter according to MRI data, and analyzed the correlation of metabolites with water molecular diffusion. Results demonstrated that in normal-appearing white matter, N-acetylaspartate/creatine ratios were positively correlated with fractional anisotropy values, negatively correlated with radial diffusivities, and positively correlated with maximum eigenvalues. Maximum eigenvalues and radial diffusivities in peritumoral edema showed a negative correlation with choline, N-acetylaspartate, and creatine. Radial diffusivities in tumor demonstrated a negative correlation with choline. These data suggest that the relationship between metabolism and structure is markedly changed from normal white matter to peritumoral edema and tumor. Neural metabolism in the peritumoral edema area decreased with expanding extracellular space. The normal relationship of neural function and microstructure disappeared in the tumor region.

  16. Quality evaluation and species differentiation of Rhizoma coptidis by using proton nuclear magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fan Gang [College of Ethnic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu 611137 (China); Zhang Mengying [China Agricultural University, Beijing 100094 (China); Zhou Xiangdong, E-mail: zhouxd88@yahoo.cn [Department of Medicinal Chemistry, College of Pharmacy, Third Military Medical University, Chongqing 400038 (China); Lai Xianrong; Yue Qinghong; Tang Ce [College of Ethnic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu 611137 (China); Luo Weizao [Chongqing Academy of Chinese Materia Medica, Chongqing 400065 (China); Zhang Yi, E-mail: tcmzhangyi@yahoo.cn [College of Ethnic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu 611137 (China)

    2012-10-17

    Highlights: Black-Right-Pointing-Pointer We report a qNMR method for the determination of six alkaloids in Rhizoma coptidis. Black-Right-Pointing-Pointer The results of the qNMR method are reliable by comparison with a HPLC method. Black-Right-Pointing-Pointer The proposed method has good selectivity, precision, repeatability and accuracy. Black-Right-Pointing-Pointer This method coupled with chemometrics can distinguish three Rhizoma coptidis species. - Abstract: Rhizoma coptidis, a broadly used traditional Chinese medicine, derives from the dried rhizomes of Coptis chinensis Franch, Coptis deltoidea C.Y. Cheng et Hsiao and Coptis teeta Wall. Quantitative determination of protoberberine alkaloids in R. coptidis is critical for controlling its quality. In this study, a rapid, simple and accurate quantitative {sup 1}H NMR (qNMR) method was developed for simultaneous determination of berberine, jatrorrhizine, epiberberine, coptisine, palmatine and columbamine in R. coptidis from the three species. Method validation was performed in terms of selectivity, precision, repeatability, stability, accuracy, robustness and linearity. The average recoveries obtained were in the range of 96.9-102.4% for all the six alkaloids. In addition, the qNMR data were analyzed with analysis of variance (ANOVA), hierarchical clustering analysis (HCA) and principal component analysis (PCA), and the results showed that the contents of the active alkaloids have significant difference among the three species. Compared with the conventional HPLC approach, the proposed qNMR method was demonstrated to be a powerful tool for quantifying the six alkaloids due to its unique advantages of high robustness, rapid analysis time and no need of standard compounds for calibration curves preparation. These findings indicate that this method has potential as a reliable method for quality evaluation of herb medicines, especially for protoberberine alkaloid-containing ones.

  17. In vivo proton magnetic resonance spectroscopy in a known case of intracranial hydatid cyst

    Directory of Open Access Journals (Sweden)

    Chand K

    2005-01-01

    Full Text Available We are presenting magnetic resonance spectroscopy (MRS findings of a known case of hydatid cyst operated twice in the past. A 22-years-old male patient had presented with recurrent symptoms of generalized seizures and raised intracranial tension. MRI with MRS of the lesion was performed that showed a recurrent loculated cystic lesion in right parieto-occipital lobe. MRS through the lesion was performed using repetition time (TR of 1500 ms and time to echo (TE of 135 ms using 2 x 2 x 2 cm voxel, from the margin of the lesion. MRS showed mildly elevated choline (Cho, depressed creatine (Cr and N-acetyl aspartate (NAA, a large peak of lactate, pyruvate and acetate peaks.

  18. Proton magnetic resonance spectroscopy of a patient with Gerstmann-Straussler-Scheinker disease

    Energy Technology Data Exchange (ETDEWEB)

    Konaka, K.; Kaido, M.; Okuda, Y.; Aoike, F.; Abe, K.; Yanagihara, T. [Osaka Univ. Graduate School of Medicine (Japan). Dept. of Neurology; Kitamoto, T. [Tohoku Univ. Graduate School of Medicine (Japan). Dept. of Neurological Science

    2000-09-01

    A 23-year-old woman with Gerstmann-Straussler-Scheinker disease (GSS) was investigated by {sup 1}H-magnetic resonance spectroscopy ({sup 1}H-MRS). She developed gait ataxic at 22 years. The diagnosis was confirmed by DNA analysis showing a proline-to-leucine point mutation at codon 102 of the prion protein. On {sup 1}H-MRS, she showed a remarkable reduction of the N-acetylaspartate/creatine ratio in the frontal lobe, cerebellar hemisphere and vermis and putamen. MRI revealed mild atrophy of the cerebellar hemispheres and vermis and cerebral cortex, but single-photon emission computed tomography (SPECT) with {sup 99m}HMPAO showed normal perfusion in the cerebellum. The imaging studies suggest that MRS might be superior to MRI or SPECT for detection of early neuronal degeneration. (orig.)

  19. Intermolecular proton transfer in solid phase: a rare example of crystal-to-crystal transformation from hydroxo- to oxo-bridged iron(III) molecule-based magnet.

    Science.gov (United States)

    Armentano, Donatella; De Munno, Giovanni; Mastropietro, Teresa F; Julve, Miguel; Lloret, Francesc

    2005-08-10

    Intermolecular proton transfer in solid phase from the hydroxo bridge to a water molecule occurs in a new mu-hydroxo iron(III) compound of formula {EtNH3[Fe2(ox)2Cl2(mu-OH)].2H2O}n leading to a still crystalline compound in which the mu-oxo bridge replaces the mu-hydroxo one. Both three-dimensional compounds exhibit magnetic ordering at Tc ca. 70 K due to a spin canting.

  20. A Feasibility Study of Quantitative Molecular Characterization of Musculoskeletal Lesions by Proton MR Spectroscopy at 3 T

    Science.gov (United States)

    Fayad, Laura M.; Wang, Xin; Salibi, Nouha; Barker, Peter B.; Jacobs, Michael A.; Machado, Antonio J.; Weber, Kristy L.; Bluemke, David A.

    2011-01-01

    OBJECTIVE The purpose of this study is to establish the feasibility and potential value of measuring the concentration of choline-containing compounds by proton MR spectroscopy (MRS) in musculoskeletal lesions at 3 T. SUBJECTS AND METHODS Thirty-three subjects with 34 musculoskeletal lesions (four histologically proven malignant, 13 histologically proven benign or proven benign by follow-up analysis, and 17 posttreatment fibrosis with documented stability for 6–36 months) underwent single-voxel 3-T MRS studies. In each case, both water-suppressed and water-unsuppressed scans were obtained. The quality of the scans was recorded as excellent, adequate, or nondiagnostic, and the choline concentration was measured using water as the internal reference. The choline concentrations of benign and malignant lesions were compared using the Mann-Whitney test. RESULTS Spectral quality was excellent in 26 cases, adequate in four cases, and non-diagnostic in four cases. For malignant lesions (three sarcomas), the choline concentrations were 1.5, 2.9, and 3.8 mmol/kg, respectively. For five benign lesions (two neurofibromas, two schwannomas, and one enchondroma), the choline concentrations were 0.11, 0.28, 0.13, 0.8, and 1.2 mmol/kg, respectively. For seven benign lesions (two hematomas, two bone cysts, one lipoma, one giant cell tumor, and one pigmented villonodular synovitis), the spectra showed negligible choline content. For three posttreatment fibrosis cases, the choline concentration range was 0.2–0.4 mmol/kg. For the remaining 12 posttreatment fibrosis cases, the spectra showed negligible choline content. Average choline concentrations were different for malignant and benign lesions (2.7 vs 0.5 mmol/kg; p = 0.01). CONCLUSION The measurement of choline concentration within musculoskeletal lesions by MRS is feasible using an internal water-referencing method at 3 T and has potential for characterizing lesions for malignancy. PMID:20566784

  1. Quantitative multivoxel proton MR spectroscopy study of brain metabolites in patients with amnestic mild cognitive impairment: a pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhong-Xian; Cheng, Xiao-Fang; Xu, Zhi-Feng; Cao, Zhen; Xiao, Ye-Yu; You, Ke-Zeng; Liu, Yan-Yan [Medical College of Shantou University, Department of Medical Imaging, The Second Affiliated Hospital, Shantou (China); Huo, Shan-Shan [Science College of Shantou University, Department of Physics, Shantou (China); Zeng, Jie-Xia; Chen, Wei [Medical College of Shantou University, Department of Neurology, The Second Affiliated Hospital, Shantou (China); Wu, Ren-Hua [Medical College of Shantou University, Department of Medical Imaging, The Second Affiliated Hospital, Shantou (China); Medical College of Shantou University, Provincial Key Laboratory of Medical Molecular Imaging, Guangdong, Shantou (China)

    2012-05-15

    The purpose of this study is to investigate brain metabolic changes in patients with amnestic mild cognitive impairment (aMCI) using multivoxel proton MR spectroscopy ({sup 1}H-MVS). Fourteen aMCI patients and fifteen healthy control subjects participated in this experiment. All MR measurements were acquired using a 1.5-T GE scanner. {sup 1}H-MVS point resolved spectroscopy (2D PROBE-CSI PRESS) pulse sequence (TE = 35 ms; TR = 1,500 ms; phase x frequency, 18 x 18) was used for acquiring MRS data. All data were post-processed using Spectroscopy Analysis by General Electric software and linear combination of model (LCModel). The absolute concentrations of N-acetylaspartate (NAA), choline (Cho), myoinositol (MI), creatine (Cr), and the metabolite ratios of NAA/Cr, Cho/Cr, MI/Cr, and NAA/MI were measured bilaterally in the posterior cingulate gyrus (PCG), inferior precuneus (Pr), paratrigonal white matter (PWM), dorsal thalamus (DT), and lentiform nucleus (LN). Patients with aMCI displayed significantly lower NAA levels in the bilateral PCG (p < 0.01), PWM (p < 0.05), and left inferior Pr (p < 0.05). The metabolite ratio of NAA/MI was decreased in the bilateral PCG (p < 0.01) and PWM (p < 0.05) and in the left DT (p < 0.01). NAA/Cr was decreased in the left PCG (p < 0.01), DT (p < 0.05), right PWM (p < 0.05), and LN (p < 0.05). However, MI/Cr was elevated in the right PCG (p < 0.01) and left PWM (p < 0.05). Significantly increased Cho level was also evident in the left PWM (p < 0.05). Our observations of decreased NAA, NAA/Cr, and NAA/MI, in parallel with increased Cho and MI/Cr might be characteristic of aMCI patients. (orig.)

  2. Parametric study of a variable-magnetic-field-based energy-selection system for generating a spread-out Bragg peak with a laser-accelerated proton beam

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dae-Hyun; Suh, Tae-Suk [The Catholic University of Korea, Seoul (Korea, Republic of); Kang, Young-Nam [Seoul St. Mary' s Hospital, The Catholic University of Korea, Seoul (Korea, Republic of); Yoo, Seung-Hoon [CHA Bundang Medical Center, CHA University, Seongnam (Korea, Republic of); Pae, Ki-Hong [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Shin, Dong-Ho; Lee, Se-Byeong [National Cancer Center, Goyang (Korea, Republic of)

    2013-01-15

    Laser-based proton beam acceleration, which produces broad energy spectra, is unsuitable for direct clinical use. Thus, employing an energy selection system is necessary. The purpose of the present study was to investigate a method whereby a variable magnetic field could be employed with an energy selection system to generate a spread-out Bragg peak (SOBP). For energy selection, particle transport and dosimetric property measurements, the Geant4 toolkit was implemented. The energy spectrum of the laser-accelerated proton beam was acquired using a particle-in-cell simulation. The hole size and the position of the energy selection collimator were varied in order to determine the effects of those parameters on the dosimetric properties. To generate an SOBP, we changed the magnetic field in the energy selection system for each beam weighting factor during beam irradiation. The overall results of this study suggest that the use of an energy selection system with a variable magnetic field can effectively generate an SOBP suitable for proton radiation therapy applications.

  3. Investigation of the biochemical state of paramagnetic ions in vivo using the magnetic field dependence of 1T/sub 1/ of tissue protons (NMRD profile): applications to contrast agents for magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Koenig, S.H.; Brown, R.D. III; Spiller, M.; Wolf, G.L.

    1988-01-01

    Nuclear magnetic relaxation dispersion (NMRD) profiles of protons are obtained in homogenous aqueous solutions of the paramagnetic ions, Mn/sup 2 +/ and Gd/sup 3 +/ and their chelate and macromolecular complexes in vitro, giving information regarding the biochemical state of these ions. Similarly NMRD profiles of protons of excised rabbit tissues containing Mn/sup 2 +/ and Gd/sup 3 +/ complexes are obtained. These NMRD profiles are shown to be very useful for determining the fate of potentially useful paramagnetic NMR imaging contrast agents in vivo. (U.K.).

  4. Design of a mannequin for spectroscopy magnetic resonance of proton. Preliminary results of its application; Diseno de un maniqui para espectroscopia por resonancia magnetica de proton. resultados preliminares de su aplicacion

    Energy Technology Data Exchange (ETDEWEB)

    Parra Osoirio, V.; Galan Montenegro, P.; Moreno Saiz, C.; Garcia-Alvarez, R.; Arrabal Nunez, S.; Caudepon Moreno, F.; Navarro Guirado, F.; Asensjo Garcia, B.

    2013-07-01

    The proton magnetic resonance spectroscopy is a technique of metabolic Imaging allowing in vivo measurement of the levels of different metabolites. Is under increasing development and has shown an improvement of diagnostic indexes and therapeutic, since it allows: differential diagnosis between injuries, determination of tumor grade of Pre surgical form, determination of the presence of a lesion until it is clear, definition of progress and evaluation of the effects of a treatment. The aim in this work is to have a mannequin that allows analyze and adjust various parameters involved in the spectroscopic process, and establish a quantification of these parameters. (Author)

  5. Measurement of vertebral bone marrow lipid profile at 1.5-T proton magnetic resonance spectroscopy and bone mineral density at dual-energy X-ray absorptiometry: correlation in a swine model

    Energy Technology Data Exchange (ETDEWEB)

    Di Leo, Giovanni; Fina, Laura [IRCCS Policlinico San Donato, Unita di Radiologia, San Donato Milanese (Italy); Bandirali, Michele; Messina, Carmelo [Universita degli Studi di Milano, Scuola di Specializzazione in Radiodiagnostica, Milan (Italy); Sardanelli, Francesco [IRCCS Policlinico San Donato, Unita di Radiologia, San Donato Milanese (Italy); Universita degli Studi di Milano, Dipartimento di Scienze Biomediche per la Salute, San Donato Milanese (Italy)

    2014-08-15

    Bone marrow is mainly composed of red (hematopoietic) and yellow (fatty) components. Soon after the birth there is a physiological conversion of the bone marrow from red to yellow, so that the percentage of hematopoietic cells and adipocytes changes with aging. Although bone marrow adipogenesis is a physiologic process involving all mammals, recent studies showed an accelerated marrow adipogenesis associated with several chronic conditions, including osteoporosis [4] and diabetes mellitus. Moreover, this increased marrow fat is accompanied by a decrease in bone density. Marrow fat is therefore increasingly believed to influence the bone microenvironment. Diagnostic tools for quantitative measurement of bone marrow fat and bone mineral density (BMD) include proton magnetic resonance spectroscopy (MRS) and dual-energy Xray absorptiometry (DXA), respectively. Using MRS, an inverse relationship between vertebral bone marrow fat content and lumbar BMD has been demonstrated in patients affected with osteoporosis or with diabetes mellitus. In most studies, a quite standard MRS sequence has been used, with short echo times (TE) for the measurement of the bulk methylene. In this study we sought to optimize the MRS sequence in order to try to measure other fat components of the vertebral bone marrow at 1.5 T. For this purpose, we used an animal model that allowed long acquisition times and repeated measures. Moreover, we aimed at estimating in this model the relationship between vertebral bone marrow fat content at proton MRS and BMD at DXA.

  6. Quantitative Magnetic Particle Imaging Monitors the Transplantation, Biodistribution, and Clearance of Stem Cells In Vivo.

    Science.gov (United States)

    Zheng, Bo; von See, Marc P; Yu, Elaine; Gunel, Beliz; Lu, Kuan; Vazin, Tandis; Schaffer, David V; Goodwill, Patrick W; Conolly, Steven M

    2016-01-01

    Stem cell therapies have enormous potential for treating many debilitating diseases, including heart failure, stroke and traumatic brain injury. For maximal efficacy, these therapies require targeted cell delivery to specific tissues followed by successful cell engraftment. However, targeted delivery remains an open challenge. As one example, it is common for intravenous deliveries of mesenchymal stem cells (MSCs) to become entrapped in lung microvasculature instead of the target tissue. Hence, a robust, quantitative imaging method would be essential for developing efficacious cell therapies. Here we show that Magnetic Particle Imaging (MPI), a novel technique that directly images iron-oxide nanoparticle-tagged cells, can longitudinally monitor and quantify MSC administration in vivo. MPI offers near-ideal image contrast, depth penetration, and robustness; these properties make MPI both ultra-sensitive and linearly quantitative. Here, we imaged, for the first time, the dynamic trafficking of intravenous MSC administrations using MPI. Our results indicate that labeled MSC injections are immediately entrapped in lung tissue and then clear to the liver within one day, whereas standard iron oxide particle (Resovist) injections are immediately taken up by liver and spleen. Longitudinal MPI-CT imaging also indicated a clearance half-life of MSC iron oxide labels in the liver at 4.6 days. Finally, our ex vivo MPI biodistribution measurements of iron in liver, spleen, heart, and lungs after injection showed excellent agreement (R(2) = 0.943) with measurements from induction coupled plasma spectrometry. These results demonstrate that MPI offers strong utility for noninvasively imaging and quantifying the systemic distribution of cell therapies and other therapeutic agents.

  7. Propofol allows precise quantitative arterial spin labelling functional magnetic resonance imaging in the rat.

    Science.gov (United States)

    Griffin, Karen M; Blau, Christoph W; Kelly, Michael E; O'Herlihy, Colm; O'Connell, P R; Jones, James F X; Kerskens, Christian M

    2010-07-15

    Functional magnetic resonance imaging (fMRI) techniques highlight cerebral vascular responses which are coupled to changes in neural activation. However, two major difficulties arise when employing these techniques in animal studies. First is the disturbance of cerebral blood flow due to anaesthesia and second is the difficulty of precise reproducible quantitative measurements. These difficulties were surmounted in the current study by using propofol and quantitative arterial spin labelling (QASL) to measure relative cerebral blood volume of labelled water (rCBV(lw),) mean transit time (MTT) and capillary transit time (CTT). The ASL method was applied to measure the haemodynamic response in the primary somatosensory cortex following forepaw stimulation in the rat. Following stimulation an increase in signal intensity and rCBV(lw) was recorded, this was accompanied by a significant decrease in MTT (1.97+/-0.06s to 1.44+/-0.04s) and CTT (1.76+/-0.06s to 1.39+/-0.07s). Two animals were scanned repeatedly on two different experimental days. Stimulation in the first animal was applied to the same forepaw during the initial and repeat scan. In the second animal stimulation was applied to different forepaws on the first and second days. The control and activated ASL signal intensities, rCBVlw on both days were almost identical in both animals. The basal MTT and CTT during the second scan were also very similar to the values obtained during the first scan. The MTT recorded from the animal that underwent stimulation to the same paw during both scanning sessions was very similar on the first and second days. In conclusion, propofol induces little physiological disturbance and holds potential for longitudinal QASL fMRI studies.

  8. Molecular Imaging of Tumors Using a Quantitative T1 Mapping Technique via Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    Kelsey Herrmann

    2015-07-01

    Full Text Available Magnetic resonance imaging (MRI of glioblastoma multiforme (GBM with molecular imaging agents would allow for the specific localization of brain tumors. Prior studies using T1-weighted MR imaging demonstrated that the SBK2-Tris-(Gd-DOTA3 molecular imaging agent labeled heterotopic xenograft models of brain tumors more intensely than non-specific contrast agents using conventional T1-weighted imaging techniques. In this study, we used a dynamic quantitative T1 mapping strategy to more objectively compare intra-tumoral retention of the SBK2-Tris-(Gd-DOTA3 agent over time in comparison to non-targeted control agents. Our results demonstrate that the targeted SBK2-Tris-(Gd-DOTA3 agent, a scrambled-Tris-(Gd-DOTA3 control agent, and the non-specific clinical contrast agent Optimark™ all enhanced flank tumors of human glioma cells with similar maximal changes on T1 mapping. However, the retention of the agents differs. The non-specific agents show significant recovery within 20 min by an increase in T1 while the specific agent SBK2-Tris-(Gd-DOTA3 is retained in the tumors and shows little recovery over 60 min. The retention effect is demonstrated by percent change in T1 values and slope calculations as well as by calculations of gadolinium concentration in tumor compared to muscle. Quantitative T1 mapping demonstrates the superior binding and retention in tumors of the SBK2-Tris-(Gd-DOTA3 agent over time compared to the non-specific contrast agent currently in clinical use.

  9. Characterization of proton exchange membrane materials for fuel cells by solid state nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Zueqian [Iowa State Univ., Ames, IA (United States)

    2010-01-01

    Solid-state nuclear magnetic resonance (NMR) has been used to explore the nanometer-scale structure of Nafion, the widely used fuel cell membrane, and its composites. We have shown that solid-state NMR can characterize chemical structure and composition, domain size and morphology, internuclear distances, molecular dynamics, etc. The newly-developed water channel model of Nafion has been confirmed, and important characteristic length-scales established. Nafion-based organic and inorganic composites with special properties have also been characterized and their structures elucidated. The morphology of Nafion varies with hydration level, and is reflected in the changes in surface-to-volume (S/V) ratio of the polymer obtained by small-angle X-ray scattering (SAXS). The S/V ratios of different Nafion models have been evaluated numerically. It has been found that only the water channel model gives the measured S/V ratios in the normal hydration range of a working fuel cell, while dispersed water molecules and polymer ribbons account for the structures at low and high hydration levels, respectively.

  10. Investigating the Dissolution Performance of Amorphous Solid Dispersions Using Magnetic Resonance Imaging and Proton NMR.

    Science.gov (United States)

    Tres, Francesco; Coombes, Steven R; Phillips, Andrew R; Hughes, Leslie P; Wren, Stephen A C; Aylott, Jonathan W; Burley, Jonathan C

    2015-09-10

    We have investigated the dissolution performance of amorphous solid dispersions of poorly water-soluble bicalutamide in a Kollidon VA64 polymeric matrix as a function of the drug loading (5% vs. 30% bicalutamide). A combined suite of state-of-the-art analytical techniques were employed to obtain a clear picture of the drug release, including an integrated magnetic resonance imaging UV-Vis flow cell system and 1H-NMR. Off-line 1H-NMR was used for the first time to simultaneously measure the dissolution profiles and rates of both the drug and the polymer from a solid dispersion. MRI and 1H-NMR data showed that the 5% drug loading compact erodes linearly, and that bicalutamide and Kollidon VA64 are released at approximately the same rate from the molecular dispersion. For the 30% extrudate, data indicated a slower water ingress into the compact which corresponds to a slower dissolution rate of both bicalutamide and Kollidon VA64.

  11. Investigating the Dissolution Performance of Amorphous Solid Dispersions Using Magnetic Resonance Imaging and Proton NMR

    Directory of Open Access Journals (Sweden)

    Francesco Tres

    2015-09-01

    Full Text Available We have investigated the dissolution performance of amorphous solid dispersions of poorly water-soluble bicalutamide in a Kollidon VA64 polymeric matrix as a function of the drug loading (5% vs. 30% bicalutamide. A combined suite of state-of-the-art analytical techniques were employed to obtain a clear picture of the drug release, including an integrated magnetic resonance imaging UV-Vis flow cell system and 1H-NMR. Off-line 1H-NMR was used for the first time to simultaneously measure the dissolution profiles and rates of both the drug and the polymer from a solid dispersion. MRI and 1H-NMR data showed that the 5% drug loading compact erodes linearly, and that bicalutamide and Kollidon VA64 are released at approximately the same rate from the molecular dispersion. For the 30% extrudate, data indicated a slower water ingress into the compact which corresponds to a slower dissolution rate of both bicalutamide and Kollidon VA64.

  12. Proton magnetic resonance spectroscopy detection of neurotransmitters in dorsomedial medulla correlate with spontaneous baroreceptor reflex function.

    Science.gov (United States)

    Garcia-Espinosa, Maria A; Shaltout, Hossam A; Olson, John; Westwood, Brian M; Robbins, Mike E; Link, Kerry; Diz, Debra I

    2010-02-01

    Control of heart rate variability via modulation of sympathovagal balance is a key function of nucleus tractus solitarii and the dorsal motor nucleus of the vagus localized in the dorsomedial medulla oblongata. Normal blood pressure regulation involves precise balance of glutamate (Glu)-glutamine-gamma-aminobutyric acid transmitter systems, and angiotensin II modulates these transmitters to produce tonic suppression of reflex function. It is not known, however, whether other brain transmitters/metabolites are indicators of baroreflex function. This study establishes the concept that comprehensive baseline transmitter/metabolite profiles obtained using in vivo (1)H magnetic resonance spectroscopy in rats with well-characterized differences in resting blood pressure and baroreflex function can be used as indices of autonomic balance or baroreflex sensitivity. Transgenic rats with over-expression of renin [m(Ren2)27] or under-expression of glial-angiotensinogen (ASrAogen) were compared with Sprague-Dawley rats. Glu concentration in the dorsal medulla is significantly higher in ASrAogen rats compared with either Sprague-Dawley or (mRen2)27 rats. Glu levels and the ratio of Glu:glutamine correlated positively with indices of higher vagal tone consistent with the importance of these neurotransmitters in baroreflex function. Interestingly, the levels of choline-containing metabolites showed a significant positive correlation with spontaneous baroreflex sensitivity and a negative correlation with sympathetic tone. Thus, we demonstrate the concept that noninvasive assessment of neurochemical biomarkers may be used as an index of baroreflex sensitivity.

  13. Proton: the particle.

    Science.gov (United States)

    Suit, Herman

    2013-11-01

    The purpose of this article is to review briefly the nature of protons: creation at the Big Bang, abundance, physical characteristics, internal components, and life span. Several particle discoveries by proton as the experimental tool are considered. Protons play important roles in science, medicine, and industry. This article was prompted by my experience in the curative treatment of cancer patients by protons and my interest in the nature of protons as particles. The latter has been stimulated by many discussions with particle physicists and reading related books and journals. Protons in our universe number ≈10(80). Protons were created at 10(-6) -1 second after the Big Bang at ≈1.37 × 10(10) years beforethe present. Proton life span has been experimentally determined to be ≥10(34) years; that is, the age of the universe is 10(-24)th of the minimum life span of a proton. The abundance of the elements is hydrogen, ≈74%; helium, ≈24%; and heavier atoms, ≈2%. Accordingly, protons are the dominant baryonic subatomic particle in the universe because ≈87% are protons. They are in each atom in our universe and thus involved in virtually every activity of matter in the visible universe, including life on our planet. Protons were discovered in 1919. In 1968, they were determined to be composed of even smaller particles, principally quarks and gluons. Protons have been the experimental tool in the discoveries of quarks (charm, bottom, and top), bosons (W(+), W(-), Z(0), and Higgs), antiprotons, and antineutrons. Industrial applications of protons are numerous and important. Additionally, protons are well appreciated in medicine for their role in radiation oncology and in magnetic resonance imaging. Protons are the dominant baryonic subatomic particle in the visible universe, comprising ≈87% of the particle mass. They are present in each atom of our universe and thus a participant in every activity involving matter. Copyright © 2013 Elsevier Inc. All

  14. Geomagnetic field intensity and quantitative paleorainfall reconstruction from Chinese loess using 10Be and magnetic susceptibility

    Science.gov (United States)

    Beck, W.; zhou, W.; Li, C.; Wu, Z.; White, L.; Xian, F.

    2011-12-01

    7Be is produced in the atmosphere by cosmic ray spallation reactions and carried to the ground attached to aerosols, usually encapsulated in rain or snow. Numerous studies have shown that its flux to the ground is proportional to rainfall amount. Unfortunately, with a half life of only a few weeks, this observation has little relevance for reconstruction past rainfall amounts in paleosoils. Fortunately, 7Be has a long-lived sister isotope (10Be) with a half life of ~1.5 Ma which can be used for such purposes. There are a number of complications, however. First, 10Be atmospheric production rate changes when the geomagnetic field intensity changes. Secondly, 10Be half life is long enough that 10Be which fell to the ground attached to dust some time in the past can become resuspended, meaning that there are two sources of 10Be, one meteoric, and the other recycled aeolian dust. Fortunately, we have found a method to deconvolute this knotty situation and have applied it to soils of the Chinese Loess Plateau, allowing us to reconstruct records of both geomagnetic field intensity and paleorainfall. To do so, we use the additional parameters magnetic susceptibility and coercivity to help define the inherited amount of each component, and to define what fraction of the variations in 10Be are associated with magnetic field fluctuations, versus that linked to rainfall variations. We also use a sediment age/depth model to convert 10Be concentration to 10Be flux, and finally, we use the modern 7Be vs. rainfall relationship and 10Be/7Be atmospheric production rate ratio to calculate quantitative paleorainfall rates. We have used these techniques to generate several such records ranging from the Holocene to MIS13 (Circa 525 ka BP), and will compare some of these to U-series dated speleothem records of δ18O.

  15. Quantitative study of liver magnetic resonance spectroscopy quality at 3T using body and phased array coils with physical analysis and clinical evaluation.

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    Li Xu

    Full Text Available This study aims to investigate the quality difference of short echo time (TE breathhold 1H magnetic resonance spectroscopy (MRS of the liver at 3.0T using the body and phased array coils, respectively. In total, 20 pairs of single-voxel proton spectra of the liver were acquired at 3.0T using the phased array and body coils as receivers. Consecutive stacks of breathhold spectra were acquired using the point resolved spectroscopy (PRESS technique at a short TE of 30 ms and a repetition time (TR of 1500 ms. The first spectroscopy sequence was "copied" for the second acquisition to ensure identical voxel positioning. The MRS prescan adjustments of shimming and water suppression, signal-to noise ratio (SNR, and major liver quantitative information were compared between paired spectra. Theoretical calculation of the SNR and homogeneity of the region of interest (ROI, 2 cm×2 cm×2 cm using different coils loaded with 3D liver electromagnetic model of real human body was implemented in the theoretical analysis. The theoretical analysis showed that, inside the ROI, the SNR of the phase array coil was 2.8387 times larger than that of body coil and the homogeneity of the phase array coil and body coil was 80.10% and 93.86%, respectively. The experimental results showed excellent correlations between the paired data (all r > 0.86. Compared with the body coil group, the phased array group had slightly worse shimming effect and better SNR (all P values 0.05. The theoretical analysis and clinical experiment showed that the phased array coil was superior to the body coil with respect to 3.0T breathhold hepatic proton MRS.

  16. Quantitative and qualitative assessment of structural magnetic resonance imaging data in a two-center study

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    Chalavi Sima

    2012-08-01

    Full Text Available Abstract Background Multi-center magnetic resonance imaging (MRI studies present an opportunity to advance research by pooling data. However, brain measurements derived from MR-images are susceptible to differences in MR-sequence parameters. It is therefore necessary to determine whether there is an interaction between the sequence parameters and the effect of interest, and to minimise any such interaction by careful choice of acquisition parameters. As an exemplar of the issues involved in multi-center studies, we present data from a study in which we aimed to optimize a set of volumetric MRI-protocols to define a protocol giving data that are consistent and reproducible across two centers and over time. Methods Optimization was achieved based on data quality and quantitative measures, in our case using FreeSurfer and Voxel Based Morphometry approaches. Our approach consisted of a series of five comparisons. Firstly, a single-center dataset was collected, using a range of candidate pulse-sequences and parameters chosen on the basis of previous literature. Based on initial results, a number of minor changes were implemented to optimize the pulse-sequences, and a second single-center dataset was collected. FreeSurfer data quality measures were compared between datasets in order to determine the best performing sequence(s, which were taken forward to the next stage of testing. We subsequently acquired short-term and long-term two-center reproducibility data, and quantitative measures were again assessed to determine the protocol with the highest reproducibility across centers. Effects of a scanner software and hardware upgrade on the reproducibility of the protocols at one of the centers were also evaluated. Results Assessing the quality measures from the first two datasets allowed us to define artefact-free protocols, all with high image quality as assessed by FreeSurfer. Comparing the quantitative test and retest measures, we found high within

  17. Probing articular cartilage damage and disease by quantitative magnetic resonance imaging.

    Science.gov (United States)

    Chan, Deva D; Neu, Corey P

    2013-01-06

    Osteoarthritis (OA) is a debilitating disease that reflects a complex interplay of biochemical, biomechanical, metabolic and genetic factors, which are often triggered by injury, and mediated by inflammation, catabolic cytokines and enzymes. An unmet clinical need is the lack of reliable methods that are able to probe the pathogenesis of early OA when disease-rectifying therapies may be most effective. Non-invasive quantitative magnetic resonance imaging (qMRI) techniques have shown potential for characterizing the structural, biochemical and mechanical changes that occur with cartilage degeneration. In this paper, we review the background in articular cartilage and OA as it pertains to conventional MRI and qMRI techniques. We then discuss how conventional MRI and qMRI techniques are used in clinical and research environments to evaluate biochemical and mechanical changes associated with degeneration. Some qMRI techniques allow for the use of relaxometry values as indirect biomarkers for cartilage components. Direct characterization of mechanical behaviour of cartilage is possible via other specialized qMRI techniques. The combination of these qMRI techniques has the potential to fully characterize the biochemical and biomechanical states that represent the initial changes associated with cartilage degeneration. Additionally, knowledge of in vivo cartilage biochemistry and mechanical behaviour in healthy subjects and across a spectrum of osteoarthritic patients could lead to improvements in the detection, management and treatment of OA.

  18. Effect of arterial deprivation on growing femoral epiphysis: Quantitative magnetic resonance imaging using a piglet model

    Energy Technology Data Exchange (ETDEWEB)

    Cheon, Jung Eun; Yoo, Won Joon; Kim, In One; Kim, Woo Sun; Choi, Young Hun [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2015-06-15

    To investigate the usefulness of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion MRI for the evaluation of femoral head ischemia. Unilateral femoral head ischemia was induced by selective embolization of the medial circumflex femoral artery in 10 piglets. All MRIs were performed immediately (1 hour) and after embolization (1, 2, and 4 weeks). Apparent diffusion coefficients (ADCs) were calculated for the femoral head. The estimated pharmacokinetic parameters (Kep and Ve from two-compartment model) and semi-quantitative parameters including peak enhancement, time-to-peak (TTP), and contrast washout were evaluated. The epiphyseal ADC values of the ischemic hip decreased immediately (1 hour) after embolization. However, they increased rapidly at 1 week after embolization and remained elevated until 4 weeks after embolization. Perfusion MRI of ischemic hips showed decreased epiphyseal perfusion with decreased Kep immediately after embolization. Signal intensity-time curves showed delayed TTP with limited contrast washout immediately post-embolization. At 1-2 weeks after embolization, spontaneous reperfusion was observed in ischemic epiphyses. The change of ADC (p = 0.043) and Kep (p = 0.043) were significantly different between immediate (1 hour) after embolization and 1 week post-embolization. Diffusion MRI and pharmacokinetic model obtained from the DCE-MRI are useful in depicting early changes of perfusion and tissue damage using the model of femoral head ischemia in skeletally immature piglets.

  19. Quantitative Imaging of Cell-Permeable Magnetic Resonance Contrast Agents Using X-Ray Fluorescence

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    Paul J. Endres

    2006-10-01

    Full Text Available The inability to transduce cellular membranes is a limitation of current magnetic resonance imaging probes used in biologic and clinical settings. This constraint confines contrast agents to extracellular and vascular regions of the body, drastically reducing their viability for investigating processes and cycles in developmental biology. Conversely, a contrast agent with the ability to permeate cell membranes could be used in visualizing cell patterning, cell fate mapping, gene therapy, and, eventually, noninvasive cancer diagnosis. Therefore, we describe the synthesis and quantitative imaging of four contrast agents with the capability to cross cell membranes in sufficient quantity for detection. Each agent is based on the conjugation of a Gd(III chelator with a cellular transduction moiety. Specifically, we coupled Gd(III–diethylenetriaminepentaacetic acid DTPA and Gd(III–1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid with an 8–amino acid polyarginine oligomer and an amphipathic stilbene molecule, 4-amino-4'-(N,N-dimethylaminostilbene. The imaging modality that provided the best sensitivity and spatial resolution for direct detection of the contrast agents is synchrotron radiation x-ray fluorescence (SR-XRF. Unlike optical microscopy, SR-XRF provides two-dimensional images with resolution 103 better than 153Gd gamma counting, without altering the agent by organic fluorophore conjugation. The transduction efficiency of the intracellular agents was evaluated by T1 analysis and inductively coupled plasma mass spectrometry to determine the efficacy of each chelate-transporter combination.

  20. Quantitative 3D Analysis of Plant Roots Growing in Soil Using Magnetic Resonance Imaging.

    Science.gov (United States)

    van Dusschoten, Dagmar; Metzner, Ralf; Kochs, Johannes; Postma, Johannes A; Pflugfelder, Daniel; Bühler, Jonas; Schurr, Ulrich; Jahnke, Siegfried

    2016-03-01

    Precise measurements of root system architecture traits are an important requirement for plant phenotyping. Most of the current methods for analyzing root growth require either artificial growing conditions (e.g. hydroponics), are severely restricted in the fraction of roots detectable (e.g. rhizotrons), or are destructive (e.g. soil coring). On the other hand, modalities such as magnetic resonance imaging (MRI) are noninvasive and allow high-quality three-dimensional imaging of roots in soil. Here, we present a plant root imaging and analysis pipeline using MRI together with an advanced image visualization and analysis software toolbox named NMRooting. Pots up to 117 mm in diameter and 800 mm in height can be measured with the 4.7 T MRI instrument used here. For 1.5 l pots (81 mm diameter, 300 mm high), a fully automated system was developed enabling measurement of up to 18 pots per day. The most important root traits that can be nondestructively monitored over time are root mass, length, diameter, tip number, and growth angles (in two-dimensional polar coordinates) and spatial distribution. Various validation measurements for these traits were performed, showing that roots down to a diameter range between 200 μm and 300 μm can be quantitatively measured. Root fresh weight correlates linearly with root mass determined by MRI. We demonstrate the capabilities of MRI and the dedicated imaging pipeline in experimental series performed on soil-grown maize (Zea mays) and barley (Hordeum vulgare) plants.

  1. Longitudinal metabolic changes in the hippocampus and thalamus of the maternal brain revealed by proton magnetic resonance spectroscopy.

    Science.gov (United States)

    Zhou, Iris Y; Chan, Russell W; Ho, Leon C; Wu, Ed X

    2013-10-11

    Pregnancy is accompanied by dramatic hormonal changes, which are essential for the display of maternal behaviors. Reproductive hormones have been shown to remodel the neuronal structure and function of the female brain. However, most previous studies have examined the structural and functional changes elicited by transient fluctuations in reproductive hormones. The impact of naturally elevated and more sustained hormonal alterations during pregnancy and lactation are not fully understood. Further alterations in neurochemistry, which may result in substantial changes in the structure and function of neurons that are associated with behavioral modifications in the maternal female, are difficult to capture in a longitudinal and non-invasive manner. In this study, neurobiological alterations during pregnancy and motherhood were investigated longitudinally using non-invasive proton magnetic resonance spectroscopy ((1)H MRS) at 7T in regions related to learning and memory, such as the hippocampus, and in structures involved in alertness and attention, such as the thalamus. Pregnant primiparous rats (N=15) were studied at three days before mating, gestational day 17, lactation day 7 and post-weaning day 7. Age-matched nulliparous female rats (N=9) served as non-pregnant controls. Significantly higher N-acetylaspartate (NAA) levels were observed in the hippocampus and thalamus of rats at gestational day 17. These increases may be associated with increased dendritic sprouting, synaptogenesis or neurogenesis, thereby facilitating supporting behaviors that involve spatial learning and memory and alleviating fear and stress. The (1)H MRS detection of ongoing neurochemical changes induced by pregnancy, especially in the hippocampus, can shed light on the neurochemical underpinnings of behavioral modifications, including the improvement in spatial learning and memory, during pregnancy.

  2. AQP4 expression and its correlation with the Lac and NAA using proton magnetic resonance spectroscopy after rat cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ren-lan; XIE Peng

    2006-01-01

    Objective: To determine whether AQP4 expression is associated with lactate (Lac) and Nacetyl aspartate (NAA) and with apparent diffusion coefficient (ADC) abnormality after rat cerebral ischemia. Methods: The time courses of ADC and lactate and NAA assessed by proton magnetic resonance spectroscopy (1HMRS) were investigated at the time point of 6 h, and 1, 3, 7 d after rat cerebral ischemia induced by middle cerebral artery occlusion. Expression of AQP4 mRNA and protein were measured using RT-PCR and Western blot analysis respectively. Results: Significant reductions of NAA concentration and increases of lactate concentration were found after rat cerebral ischemia. The expressions of AQP4 mRNA and protein were increased at 6 h, and reached the peak at 1-3 d, then began to decrease at 7 d after rat cerebral ischemia. The expression of AQP4 was significantly correlated with NAA (rRT =-0.856, rw =-0. 927, P<0. 01), and with lactate (rW=0. 473, rRT=0. 413, P<0. 05), and with ADC values during the period of 1-7 d after rat cerebral ischemia (rW=0. 984, rRT= -0. 925, P<0.05). In addition, correlations between Lac and the ADC values(r=-0. 677, P<0. 05)and between NAA and ADC values during the period of 1-7 d after rat cerebral ischemia (r= 0. 909, P<0.05) were also observed. Conclusion: The data suggest that AQP4 is involved in the transport of water when brain edema is formed and cell membrane integrity is lost.

  3. Metabolic changes in the visual cortex of binocular blindness macaque monkeys: a proton magnetic resonance spectroscopy study.

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    Lingjie Wu

    Full Text Available PURPOSE: To evaluate proton magnetic resonance spectroscopy ((1H-MRS in a study of cross-modal plasticity in the visual cortex of binocular blindness macaque monkeys. MATERIALS AND METHODS: Four healthy neonatal macaque monkeys were randomly divided into 2 groups, with 2 in each group. Optic nerve transection was performed in both monkeys in the experimental group (group B to obtain binocular blindness. Two healthy macaque monkeys served as a control group (group A. After sixteen months post-procedure, (1H-MRS was performed in the visual cortex of all monkeys. We compared the peak areas of NAA, Cr, Cho, Glx and Ins and the ratios of NAA/Cr, Cho/Cr, Glx/Cr and Ins/Cr of each monkey in group B with group A. RESULTS: The peak area of NAA and the NAA/Cr ratio in the visual cortex of monkey 4 in group B were found to be dramatically decreased, the peak area of NAA slightly decreased and the NAA/Cr ratio clearly decreased in visual cortex of monkey 3 in group B than those in group A. The peak area of Ins and the Ins/Cr ratio in the visual cortex of monkey 4 in group B slightly increased. The peak area of Cho and the Cho/Cr ratio in the visual cortex of all monkeys in group B dramatically increased compared with group A. The peak area of Glx in the visual cortex of all monkeys in group B slightly increased compared with group A. CONCLUSIONS: (1H-MRS could detect biochemical and metabolic changes in the visual cortex and therefore this technique can be used to provide valuable information for investigating the mechanisms of cross-modal plasticity of binocular blindness in a macaque monkey model.

  4. Brain metabolite changes on proton magnetic resonance spectroscopy in children with poorly controlled type 1 diabetes mellitus

    Energy Technology Data Exchange (ETDEWEB)

    Sarac, K.; Alkan, A.; Baysal, T. [Inonu University School of Medicine, Department of Radiology, Malatya (Turkey); Akinci, A.; Aslan, M. [Inonu University School of Medicine, Department of Paediatric Endocrinology, Malatya (Turkey); Oezcan, C. [Inonu University School of Medicine, Department of Neurology, Malatya (Turkey)

    2005-07-01

    The metabolite changes in the brains of children with poorly controlled type 1 diabetes mellitus (DM) were investigated by proton magnetic resonance spectroscopy (MRS). A total of 30 subjects and 14 age-matched healthy volunteers underwent single-voxel MRS (TE: 136). The duration of disease, medication, presence of hypoglycaemia episodes and the level of haemoglobin A1C (HbA1C) in the patients were noted. Voxels were placed in the pons, left basal ganglion (LBG) and left posterior parietal white matter (PPWM). N-acetylaspartate (NAA)/creatinine (Cr) and choline (Cho)/Cr ratios were calculated. The average HbA1c level was 11.9{+-}3.4 (8.2-19.4). The average number of keto-acidosis episodes was 1.9{+-}2.2 (0-9) and the average number of daily insulin injections was 2.8{+-}0.97 (2-4). MRS revealed lower NAA/Cr and Cho/Cr ratios in the pons and lower NAA/Cr ratio in the PPWM of patients with DM than in control subjects. No significant correlation was observed between the number of hypoglycaemia episodes and metabolite ratios. Metabolic abnormalities have been observed by MRS in the brain of poorly controlled type 1 DM children. These metabolic changes, in particular in the pons region, include a decrease in NAA, indicating neuronal loss or functional impairment, and likely explanations for a decrease in Cho may be dynamic changes in membrane lipids and/or decreased membrane turnover. (orig.)

  5. Proton magnetic resonance spectroscopy reveals neuroprotection by oral minocycline in a nonhuman primate model of accelerated NeuroAIDS.

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    Eva-Maria Ratai

    Full Text Available BACKGROUND: Despite the advent of highly active anti-retroviral therapy (HAART, HIV-associated neurocognitive disorders continue to be a significant problem. In efforts to understand and alleviate neurocognitive deficits associated with HIV, we used an accelerated simian immunodeficiency virus (SIV macaque model of NeuroAIDS to test whether minocycline is neuroprotective against lentiviral-induced neuronal injury. METHODOLOGY/PRINCIPAL FINDINGS: Eleven rhesus macaques were infected with SIV, depleted of CD8+ lymphocytes, and studied until eight weeks post inoculation (wpi. Seven animals received daily minocycline orally beginning at 4 wpi. Neuronal integrity was monitored in vivo by proton magnetic resonance spectroscopy and post-mortem by immunohistochemistry for synaptophysin (SYN, microtubule-associated protein 2 (MAP2, and neuronal counts. Astrogliosis and microglial activation were quantified by measuring glial fibrillary acidic protein (GFAP and ionized calcium binding adaptor molecule 1 (IBA-1, respectively. SIV infection followed by CD8+ cell depletion induced a progressive decline in neuronal integrity evidenced by declining N-acetylaspartate/creatine (NAA/Cr, which was arrested with minocycline treatment. The recovery of this ratio was due to increases in NAA, indicating neuronal recovery, and decreases in Cr, likely reflecting downregulation of glial cell activation. SYN, MAP2, and neuronal counts were found to be higher in minocycline-treated animals compared to untreated animals while GFAP and IBA-1 expression were decreased compared to controls. CSF and plasma viral loads were lower in MN-treated animals. CONCLUSIONS/SIGNIFICANCE: In conclusion, oral minocycline alleviates neuronal damage induced by the AIDS virus.

  6. Binge Toluene Exposure Alters Glutamate, Glutamine and GABA in the Adolescent Rat Brain as Measured by Proton Magnetic Resonance Spectroscopy*

    Science.gov (United States)

    Perrine, Shane A.; O'Leary-Moore, Shonagh K.; Galloway, Matthew P.; Hannigan, John H.; Bowen, Scott E.

    2010-01-01

    Despite the high incidence of toluene abuse in adolescents, little is known regarding the effect of binge exposure on neurochemical profiles during this developmental stage. In the current study, the effects of binge toluene exposure during adolescence on neurotransmitter levels were determined using high-resolution proton magnetic resonance spectroscopy ex vivo at 11.7 T. Adolescent male Sprague-Dawley rats were exposed to toluene (0, 8,000 , or 12,000 ppm) for 15 min twice daily from postnatal day 28 (P28) through P34 and then euthanized either one or seven days later (on P35 or P42) to assess glutamate, glutamine, and GABA levels in intact tissue punches from the medial prefrontal cortex (mPFC), anterior striatum and hippocampus. In the mPFC, toluene reduced glutamate one day after exposure, with no effect on GABA, while after seven days, glutamate was no longer affected but there was an increase in GABA levels. In the hippocampus, neither GABA nor glutamate was altered one day after exposure, whereas seven days after exposure, increases were observed in GABA and glutamate. Striatal glutamate and GABA levels measured after either one or seven days were not altered after toluene exposure. These findings show that one week of binge toluene inhalation selectively alters these neurotransmitters in the mPFC and hippocampus in adolescent rats, and that some of these effects endure at least one week after the exposure. The results suggest that age-dependent, differential neurochemical responses to toluene may contribute to the unique behavioral patterns associated with drug abuse among older children and young teens. PMID:21126832

  7. Proton magnetic resonance studies on peptide fragments of troponin-C containing single calcium-binding sites.

    Science.gov (United States)

    Leavis, P C; Evans, J S; Levine, B A

    1982-07-01

    Proton magnetic resonance spectroscopy has been employed to study the solution conformation of three cleavage fragments of troponin-C, each containing a single Ca(II)-binding site and corresponding to different regions in the primary sequence; viz. CB8 (residues 46-77), CB9 (residues 85-134) and TH2 (residues 121-159). Although all three peptides lack a well-defined tertiary fold in the absence of metal ions, several spectral features indicate the presence of local conformational constraints in each apo-peptide. Ca(II) binding led to spectral changes consistent with increased restriction of backbone motility and the adoption of a more compact conformation. Studies using paramagnetic ions as conformational probes support current views concerning the nature of the ligands at the metal binding sites. The nature and kinetics of the structural influence of metal binding suggest that the conformational constraints existing in the CB8 apo-peptide provide an adequate Ca(II)-binding configuration. In contrast, the CB9 and TH2 peptides exhibit spectral changes consistent with an increased local structure in the region of helix E (residues 94-102) in the case of CB9 and helix H (residues 148-159) in the case of TH2. In CB9, conformation changes also appear to be transmitted to a portion of the sequence (residues 87-93) preceding helix E, a putative site of interaction between troponin-C and troponin-I. These data are discussed with reference to the contribution of long-range (interdomain) interactions within troponin-C and the modulation of troponin subunit protein-protein interactions by Ca(II) binding.

  8. Diet-Quality Scores and Prevalence of Nonalcoholic Fatty Liver Disease: A Population Study Using Proton-Magnetic Resonance Spectroscopy.

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    Ruth Chan

    Full Text Available Dietary pattern analysis is an alternative approach to examine the association between diet and nonalcoholic fatty liver disease (NAFLD. This study examined the association of two diet-quality scores, namely Diet Quality Index-International (DQI-I and Mediterranean Diet Score (MDS with NAFLD prevalence. Apparently healthy Chinese adults (332 male, 465 female aged 18 years or above were recruited through a population screening between 2008 and 2010 in a cross-sectional population-based study in Hong Kong. DQI-I and MDS, as well as major food group and nutrient intakes were calculated based on dietary data from a food frequency questionnaire. NAFLD was defined as intrahepatic triglyceride content at ≥5% by proton-magnetic resonance spectroscopy. Multivariate logistic regression models were used to examine the association between each diet-quality score or dietary component and prevalent NAFLD with adjustment for potential lifestyle, metabolic and genetic factors. A total of 220 subjects (27.6% were diagnosed with NAFLD. DQI-I but not MDS was associated with the prevalence of NAFLD. A 10-unit decrease in DQI-I was associated with 24% increase in the likelihood of having NAFLD in the age and sex adjusted model (95% CI: 1.06-1.45, p = 0.009, and the association remained significant when the model was further adjusted for other lifestyle factors, metabolic and genetic factors [OR: 1.26 (95% CI: 1.03-1.54, p = 0.027]. Multivariate regression analyses showed an inverse association of the intake of vegetables and legumes, fruits and dried fruits, as well as vitamin C with the NAFLD prevalence (p<0.05. In conclusion, a better diet quality as characterized by a higher DQI-I and a higher consumption of vegetables, legumes and fruits was associated with a reduced likelihood of having NAFLD in Hong Kong Chinese.

  9. Accuracy and stability of measuring GABA, glutamate, and glutamine by proton magnetic resonance spectroscopy: A phantom study at 4 Tesla

    Science.gov (United States)

    Henry, Michael E.; Lauriat, Tara L.; Shanahan, Meghan; Renshaw, Perry F.; Jensen, J. Eric

    2011-02-01

    Proton magnetic resonance spectroscopy has the potential to provide valuable information about alterations in gamma-aminobutyric acid (GABA), glutamate (Glu), and glutamine (Gln) in psychiatric and neurological disorders. In order to use this technique effectively, it is important to establish the accuracy and reproducibility of the methodology. In this study, phantoms with known metabolite concentrations were used to compare the accuracy of 2D J-resolved MRS, single-echo 30 ms PRESS, and GABA-edited MEGA-PRESS for measuring all three aforementioned neurochemicals simultaneously. The phantoms included metabolite concentrations above and below the physiological range and scans were performed at baseline, 1 week, and 1 month time-points. For GABA measurement, MEGA-PRESS proved optimal with a measured-to-target correlation of R2 = 0.999, with J-resolved providing R2 = 0.973 for GABA. All three methods proved effective in measuring Glu with R2 = 0.987 (30 ms PRESS), R2 = 0.996 (J-resolved) and R2 = 0.910 (MEGA-PRESS). J-resolved and MEGA-PRESS yielded good results for Gln measures with respective R2 = 0.855 (J-resolved) and R2 = 0.815 (MEGA-PRESS). The 30 ms PRESS method proved ineffective in measuring GABA and Gln. When measurement stability at in vivo concentration was assessed as a function of varying spectral quality, J-resolved proved the most stable and immune to signal-to-noise and linewidth fluctuation compared to MEGA-PRESS and 30 ms PRESS.

  10. Amide Proton Transfer Magnetic Resonance Imaging of Alzheimer′s Disease at 3.0 Tesla: A Preliminary Study

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    Rui Wang

    2015-01-01

    Full Text Available Background: Amide proton transfer (APT imaging has recently emerged as an important contrast mechanism for magnetic resonance imaging (MRI in the field of molecular and cellular imaging. The aim of this study was to evaluate the feasibility of APT imaging to detect cerebral abnormality in patients with Alzheimer′s disease (AD at 3.0 Tesla. Methods: Twenty AD patients (9 men and 11 women; age range, 67-83 years and 20 age-matched normal controls (11 men and 9 women; age range, 63-82 years underwent APT and traditional MRI examination on a 3.0 Tesla MRI system. The magnetic resonance ratio asymmetry (MTR asym values at 3.5 ppm of bilateral hippocampi (Hc, temporal white matter regions, occipital white matter regions, and cerebral peduncles were measured on oblique axial APT images. MTR asym (3.5 ppm values of the cerebral structures between AD patients and control subjects were compared with independent samples t-test. Controlling for age, partial correlation analysis was used to investigate the associations between mini-mental state examination (MMSE and the various MRI measures among AD patients. Results: Compared with normal controls, MTR asym (3.5 ppm values of bilateral Hc were significantly increased in AD patients (right 1.24% ± 0.21% vs. 0.83% ± 0.19%, left 1.18% ± 0.18% vs. 0.80%± 0.17%, t = 3.039, 3.328, P = 0.004, 0.002, respectively. MTR asym (3.5 ppm values of bilateral Hc were significantly negatively correlated with MMSE (right r = −0.559, P = 0.013; left r = −0.461, P = 0.047. Conclusions: Increased MTR asym (3.5 ppm values of bilateral Hc in AD patients and its strong correlations with MMSE suggest that APT imaging could potentially provide imaging biomarkers for the noninvasive molecular diagnosis of AD.

  11. Graphene oxide-Fe{sub 3}O{sub 4} nanoparticle composite with high transverse proton relaxivity value for magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Venkatesha, N.; Srivastava, Chandan, E-mail: csrivastava@materials.iisc.ernet.in [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Poojar, Pavan; Geethanath, Sairam [Medical Imaging Research Centre, Dayananda Sagar Institutions, Bangalore 560078 (India); Qurishi, Yasrib [Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560012 (India)

    2015-04-21

    The potential of graphene oxide–Fe{sub 3}O{sub 4} nanoparticle (GO-Fe{sub 3}O{sub 4}) composite as an image contrast enhancing material in magnetic resonance imaging has been investigated. Proton relaxivity values were obtained in three different homogeneous dispersions of GO-Fe{sub 3}O{sub 4} composites synthesized by precipitating Fe{sub 3}O{sub 4} nanoparticles in three different reaction mixtures containing 0.01 g, 0.1 g, and 0.2 g of graphene oxide. A noticeable difference in proton relaxivity values was observed between the three cases. A comprehensive structural and magnetic characterization revealed discrete differences in the extent of reduction of the graphene oxide and spacing between the graphene oxide sheets in the three composites. The GO-Fe{sub 3}O{sub 4} composite framework that contained graphene oxide with least extent of reduction of the carboxyl groups and largest spacing between the graphene oxide sheets provided the optimum structure for yielding a very high transverse proton relaxivity value. It was found that the GO-Fe{sub 3}O{sub 4} composites possessed good biocompatibility with normal cell lines, whereas they exhibited considerable toxicity towards breast cancer cells.

  12. Mechanical-property changes of structural composite materials after low-temperature proton irradiation: Implications for use in SSC magnet systems

    Energy Technology Data Exchange (ETDEWEB)

    Morena, J. [Ace, Inc., Stuart, FL (US); Snead, C.L. Jr. [Brookhaven National Lab., Upton, NY (US); Czajkowski, C.; Skaritka, J. [SSC Lab., Dallas, TX (US)

    1993-07-01

    Longterm physical, mechanical, electrical, and other properties of advanced composites, plastics, and other polymer materials are greatly affected by high-energy proton, neutron, electron, and gamma radiation. The effects of high-energy particles on materials is a critical design parameter to consider when choosing polymeric structural, nonstructural, and elastomeric matrix resin systems. Polymer materials used for filled resins, laminates, seals, gaskets, coatings, insulation and other nonmetallic components must be chosen carefully, and reference data viewed with caution. Most reference data collected in the high-energy physics community to date reflects material property degradation using other than proton irradiations. In most instances, the data were collected for room-temperature irradiations, not 4.2 K or other cryogenic temperatures, and at doses less than 10{sup 8}--10{sup 9} Rad. Energetic proton (and the accompanying spallation-product particles) provide good simulation fidelity to the expected radiation fields predicted for the cold-mass regions of the SSC magnets, especially the corrector magnets. The authors present here results for some structural composite materials which were part of a larger irradiation-characterization of polymeric materials for SSC applications.

  13. Qualitative insight and quantitative analysis of the effect of temperature on the coercivity of a magnetic system

    Directory of Open Access Journals (Sweden)

    Mariia Moskalenko

    2016-02-01

    Full Text Available The temperature dependence of the response of a magnetic system to an applied field can be understood qualitatively by considering variations in the energy surface characterizing the system and estimated quantitatively with rate theory. In the system analysed here, Fe/Sm-Co spring magnet, the width of the hysteresis loop is reduced to a half when temperature is raised from 25 K to 300 K. This narrowing can be explained and reproduced quantitatively without invoking temperature dependence of model parameters as has typically been done in previous data analysis. The applied magnetic field lowers the energy barrier for reorientation of the magnetization but thermal activation brings the system over the barrier. A 2-dimensional representation of the energy surface is developed and used to gain insight into the transition mechanism and to demonstrate how the applied field alters the transition path. Our results show the importance of explicitly including the effect of thermal activation when interpreting experiments involving the manipulation of magnetic systems at finite temperature.

  14. Magnetic fields in M-dwarfs: quantitative results from detailed spectral synthesis in FeH lines

    CERN Document Server

    Shulyak, D; Wende, S; Kochukhov, O; Piskunov, N; Seifahrt, A

    2010-01-01

    Strong surface magnetic fields are ubiquitously found in M-dwarfs with mean intensities on the order of few thousand Gauss-three orders of magnitude higher than the mean surface magnetic field of the Sun. These fields and their interaction with photospheric convection are the main source of stellar activity, which is of big interest to study links between parent stars and their planets. Moreover, the understanding of stellar magnetism, as well as the role of different dynamo-actions in particular, is impossible without explaining magnetic fields in M-dwarfs. Measuring magnetic field intensities and geometries in such cool objects, however, is strongly limited to our ability to simulate the Zeeman effect in molecular lines. In this work, we present quantitative results of modelling and analysis of the magnetic fields in selected M-dwarfs in FeH Wing-Ford lines and strong atomic lines. Some particular FeH lines are found to be the excellent probes of the magnetic field.

  15. Magnetically-induced solid-phase microextraction fiber actuation system for quantitative headspace and liquid sampling

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, Chris; Carter, Jerry; Chambers, David M.

    2017-05-23

    A magnetically-induced SPME fiber actuation system includes a SPME fiber holder and a SPME fiber holder actuator, for holding and magnetically actuating a SPME fiber assembly. The SPME fiber holder has a plunger with a magnetic material to which the SPME fiber assembly is connected, and the magnetic SPME fiber holder actuator has an elongated barrel with a loading chamber for receiving the SPME fiber assembly-connected SPME fiber holder, and an external magnet which induces axial motion of the magnetic material of the plunger to extend/retract the SPME fiber from/into the protective needle of the SPME fiber assembly.

  16. Supersonic transient magnetic resonance elastography for quantitative assessment of tissue elasticity

    Science.gov (United States)

    Liu, Yu; Liu, Jingfei; Fite, Brett Z.; Foiret, Josquin; Ilovitsh, Asaf; Leach, J. Kent; Dumont, Erik; Caskey, Charles F.; Ferrara, Katherine W.

    2017-05-01

    Non-invasive, quantitative methods to assess the properties of biological tissues are needed for many therapeutic and tissue engineering applications. Magnetic resonance elastography (MRE) has historically relied on external vibration to generate periodic shear waves. In order to focally assess a biomaterial or to monitor the response to ablative therapy, the interrogation of a specific region of interest by a focused beam is desirable and transient MRE (t-MRE) techniques have previously been developed to accomplish this goal. Also, strategies employing a series of discrete ultrasound pulses directed to increasing depths along a single line-of-sight have been designed to generate a quasi-planar shear wave. Such ‘supersonic’ excitations have been applied for ultrasound elasticity measurements. The resulting shear wave is higher in amplitude than that generated from a single excitation and the properties of the media are simply visualized and quantified due to the quasi-planar wave geometry and the opportunity to generate the wave at the site of interest. Here for the first time, we extend the application of supersonic methods by developing a protocol for supersonic transient magnetic resonance elastography (sst-MRE) using an MR-guided focused ultrasound system capable of therapeutic ablation. We apply the new protocol to quantify tissue elasticity in vitro using biologically-relevant inclusions and tissue-mimicking phantoms, compare the results with elasticity maps acquired with ultrasound shear wave elasticity imaging (US-SWEI), and validate both methods with mechanical testing. We found that a modified time-of-flight (TOF) method efficiently quantified shear modulus from sst-MRE data, and both the TOF and local inversion methods result in similar maps based on US-SWEI. With a three-pulse excitation, the proposed sst-MRE protocol was capable of visualizing quasi-planar shear waves propagating away from the excitation location and detecting differences in shear

  17. Leucoencephalopathy with brainstem and spinal cord involvement and high lactate: quantitative magnetic resonance imaging.

    Science.gov (United States)

    Steenweg, Marianne E; Pouwels, Petra J W; Wolf, Nicole I; van Wieringen, Wessel N; Barkhof, Frederik; van der Knaap, Marjo S

    2011-11-01

    Leucoencephalopathy with brainstem and spinal cord involvement and elevated lactate is a white matter disorder caused by DARS2 mutations. The pathology is unknown. We observed striking discrepancies between improvement on longitudinal conventional magnetic resonance images and clinical deterioration and between large areas of high signal on diffusion-weighted imaging and small areas with low apparent diffusion coefficient values. These observations prompted a longitudinal and quantitative magnetic resonance imaging study. We investigated eight patients (two males, mean age 27 years). Maps of T(2) relaxation times, fractional anisotropy, apparent diffusion coefficients, signal on diffusion-weighted imaging, and axial and radial diffusivities were generated. Brain metabolites, obtained by chemical shift imaging, were quantified. Data analysis focused on: (i) white matter with low apparent diffusion coefficient; (ii) white matter with high T(2) values; (iii) white matter with intermediate T(2) values; and (iv) normal-appearing white matter. The areas were compared with similarly located areas in eight matched controls. In five patients, T(2)-weighted images, spectroscopy, apparent diffusion coefficient maps and diffusion-weighted imaging maps were compared with those obtained 5-7 years ago. In white matter with low apparent diffusion coefficient, axial and radial diffusivities were decreased and fractional anisotropy was high. T(2) values were intermediate. These areas with truly restricted diffusion were small and often observed at the periphery of areas with high T(2) values. In the white matter with high and intermediate T(2) values, apparent diffusion coefficients and axial and radial diffusivities were increased and fractional anisotropy decreased. The signal on diffusion-weighted imaging was highest in white matter with high T(2) values, an effect of T(2) shinethrough. Chemical shift imaging in both white matter types showed increased lactate, increased myo

  18. Non-additive response of blends of rice and potato starch during heating at intermediate water contents: A differential scanning calorimetry and proton nuclear magnetic resonance study.

    Science.gov (United States)

    Bosmans, Geertrui M; Pareyt, Bram; Delcour, Jan A

    2016-02-01

    The impact of different hydration levels, on gelatinization of potato starch (PS), rice starch (RS) and a 1:1 blend thereof, was investigated by differential scanning calorimetry and related to nuclear magnetic resonance proton distributions of hydrated samples, before and after heating. At 20% or 30% hydration, the visual appearance of all samples was that of a wet powder, and limited, if any, gelatinization occurred upon heating. At 30% hydration, changes in proton distributions were observed and related to plasticization of amorphous regions in the granules. At 50% hydration, the PS-RS blend appeared more liquid-like than other hydrated samples and showed more pronounced gelatinization than expected based on additive behavior of pure starches. This was due to an additional mobile water fraction in the unheated PS-RS blend, originating from differences in water distribution due to altered stacking of granules and/or altered hydration of PS due to presence of cations in RS.

  19. Functional and quantitative magnetic resonance myelography of symptomatic stenoses of the lumbar spine

    Energy Technology Data Exchange (ETDEWEB)

    Eberhardt, Knut [District Hospital Castle of Werneck, MRI Center of Excellence, Werneck (Germany); Ganslandt, Oliver [University of Erlangen-Nuremberg, Department of Neurosurgery, Erlangen (Germany); Stadlbauer, Andreas [University of Erlangen-Nuremberg, Department of Neurosurgery, Erlangen (Germany); Medical University Vienna, Department of Radiology and Nuclear Medicine, Vienna (Austria)

    2014-12-15

    The objective of this study was to demonstrate that functional, quantitative magnetic resonance myelography (MRM) allows standardized diagnosis of symptomatic lumbar spinal stenoses which show at least equal detectability compared to functional myelography and postmyelographic CT (pmCT) based on intra- and postoperative findings. We investigated 43 volunteers and 47 patients with symptomatic lumbar spinal stenoses using MRM in normal position as well as in flexion and extension in a standard whole-body MR scanner. Twenty volunteers were additionally examined under axial loading. All patients were investigated by functional myelography and pmCT and 10 patients had a functional lumbar MRM postoperatively. Range of motion and cerebrospinal fluid (CSF) volumes in normal position, flexion, extension, and under axial loading (volunteers) were assessed for each segment. Detectability was determined by using intraoperative findings, and postoperative freedom of symptoms was correlated with CSF volume changes in MRM. The ranges of motion in a standard whole-body MR scanner provide adequate scope for investigations into function (flexion and extension) in both volunteers and patients. Axial loading was associated with a mechanism of extension, albeit to a far smaller extent. Detectability of lumbar stenoses was 100 % for MRM, 58 % for conventional myelography, and 68 % for pmCT. Postoperative changes in CSF volume of levels with stenoses in MRM strongly correlated with freedom of symptoms (R = 0.772). This MRM method allows for exact diagnosis and reproducible quantification of stenoses, motion-related changes, and spondylolistheses of the lumbar spine. It may be useful for early detection of alterations in order to avoid neuronal compression. (orig.)

  20. Quantitative correlational study of microbubble-enhanced ultrasound imaging and magnetic resonance imaging of glioma and early response to radiotherapy in a rat model

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Chen [Department of Ultrasound, Zhejiang Cancer Hospital, Hangzhou, Zhejiang 310022 (China); Lee, Dong-Hoon; Zhang, Kai; Li, Wenxiao; Zhou, Jinyuan [Division of MR Research, Department of Radiology, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21287 (United States); Mangraviti, Antonella; Tyler, Betty [Department of Neurosurgery, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21287 (United States); Su, Lin; Zhang, Yin; Zhang, Bin; Wong, John; Wang, Ken Kang-Hsin; Velarde, Esteban; Ding, Kai, E-mail: kding1@jhmi.edu [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21231 (United States)

    2015-08-15

    Purpose: Radiotherapy remains a major treatment method for malignant tumors. Magnetic resonance imaging (MRI) is the standard modality for assessing glioma treatment response in the clinic. Compared to MRI, ultrasound imaging is low-cost and portable and can be used during intraoperative procedures. The purpose of this study was to quantitatively compare contrast-enhanced ultrasound (CEUS) imaging and MRI of irradiated gliomas in rats and to determine which quantitative ultrasound imaging parameters can be used for the assessment of early response to radiation in glioma. Methods: Thirteen nude rats with U87 glioma were used. A small thinned skull window preparation was performed to facilitate ultrasound imaging and mimic intraoperative procedures. Both CEUS and MRI with structural, functional, and molecular imaging parameters were performed at preradiation and at 1 day and 4 days postradiation. Statistical analysis was performed to determine the correlations between MRI and CEUS parameters and the changes between pre- and postradiation imaging. Results: Area under the curve (AUC) in CEUS showed significant difference between preradiation and 4 days postradiation, along with four MRI parameters, T{sub 2}, apparent diffusion coefficient, cerebral blood flow, and amide proton transfer-weighted (APTw) (all p < 0.05). The APTw signal was correlated with three CEUS parameters, rise time (r = − 0.527, p < 0.05), time to peak (r = − 0.501, p < 0.05), and perfusion index (r = 458, p < 0.05). Cerebral blood flow was correlated with rise time (r = − 0.589, p < 0.01) and time to peak (r = − 0.543, p < 0.05). Conclusions: MRI can be used for the assessment of radiotherapy treatment response and CEUS with AUC as a new technique and can also be one of the assessment methods for early response to radiation in glioma.

  1. Quantitative correlational study of microbubble-enhanced ultrasound imaging and magnetic resonance imaging of glioma and early response to radiotherapy in a rat model.

    Science.gov (United States)

    Yang, Chen; Lee, Dong-Hoon; Mangraviti, Antonella; Su, Lin; Zhang, Kai; Zhang, Yin; Zhang, Bin; Li, Wenxiao; Tyler, Betty; Wong, John; Wang, Ken Kang-Hsin; Velarde, Esteban; Zhou, Jinyuan; Ding, Kai

    2015-08-01

    Radiotherapy remains a major treatment method for malignant tumors. Magnetic resonance imaging (MRI) is the standard modality for assessing glioma treatment response in the clinic. Compared to MRI, ultrasound imaging is low-cost and portable and can be used during intraoperative procedures. The purpose of this study was to quantitatively compare contrast-enhanced ultrasound (CEUS) imaging and MRI of irradiated gliomas in rats and to determine which quantitative ultrasound imaging parameters can be used for the assessment of early response to radiation in glioma. Thirteen nude rats with U87 glioma were used. A small thinned skull window preparation was performed to facilitate ultrasound imaging and mimic intraoperative procedures. Both CEUS and MRI with structural, functional, and molecular imaging parameters were performed at preradiation and at 1 day and 4 days postradiation. Statistical analysis was performed to determine the correlations between MRI and CEUS parameters and the changes between pre- and postradiation imaging. Area under the curve (AUC) in CEUS showed significant difference between preradiation and 4 days postradiation, along with four MRI parameters, T2, apparent diffusion coefficient, cerebral blood flow, and amide proton transfer-weighted (APTw) (all p correlated with three CEUS parameters, rise time (r = - 0.527, p correlated with rise time (r = - 0.589, p < 0.01) and time to peak (r = - 0.543, p < 0.05). MRI can be used for the assessment of radiotherapy treatment response and CEUS with AUC as a new technique and can also be one of the assessment methods for early response to radiation in glioma.

  2. THE TISSUE HYDRATION STATE IN UW-PRESERVED HUMAN DONOR LIVERS - A CLINICAL-STUDY OF THE RELATION BETWEEN PROTON MAGNETIC-RESONANCE RELAXATION-TIMES, DONOR CONDITION, PRESERVATION PROCEDURE, AND EARLY GRAFT FUNCTION

    NARCIS (Netherlands)

    WOLF, RFE; DENBUTTER, G; KAMMAN, RL; DEKETH, HP; SLUTTER, WJ; SLOOFF, MJH

    1994-01-01

    To determine the relation between tissue hydration state-as indicated by tissue proton magnetic resonance relaxation times-in UW-preserved human donor livers and viability parameters of the donor and early graft function, ''ex vivo'' magnetic resonance relaxometry was performed with a clinical MR im

  3. THE TISSUE HYDRATION STATE IN UW-PRESERVED HUMAN DONOR LIVERS - A CLINICAL-STUDY OF THE RELATION BETWEEN PROTON MAGNETIC-RESONANCE RELAXATION-TIMES, DONOR CONDITION, PRESERVATION PROCEDURE, AND EARLY GRAFT FUNCTION

    NARCIS (Netherlands)

    WOLF, RFE; DENBUTTER, G; KAMMAN, RL; DEKETH, HP; SLUTTER, WJ; SLOOFF, MJH

    1994-01-01

    To determine the relation between tissue hydration state-as indicated by tissue proton magnetic resonance relaxation times-in UW-preserved human donor livers and viability parameters of the donor and early graft function, ''ex vivo'' magnetic resonance relaxometry was performed with a clinical MR

  4. Ion and proton loss paterns at the SPS and LHC

    CERN Document Server

    Bruce, R; Bellodi, G; Bracco, C; Braun, H H; Gilardoni, S; Jowett, John M; Redaelli, S; Weiler, T

    2008-01-01

    The collimation system of the LHC, primarily designed for proton operation, must function safely also with 208Pb82+ions. However, the particle-matter interaction in a collimator is different for heavy ions and protons. Heavy ions are subject to nuclear fragmentation, which creates a spectrum of secondary particles exiting the collimators with a Z/A ratio different from the nominal beam. These particles could be lost in a superconducting magnet and the induced heating might cause a quench. The program ICOSIM has previously been used to simulate these losses in the LHC. In this article, we present a benchmark of ICOSIM, using measured proton and ion loss maps in the SPS, and find a good qualitative agreement. We also make a quantitative comparison where the showers of the lost particles are simulated with the FLUKA code in the full magnet geometry. Here a discrepancy of a factor 3.8 is found. Estimation of expected uncertainties continues.

  5. Proton magnetic resonance spectroscopy predicts radiotherapy response and time-to-progression in high-grade gliomas after surgery

    Institute of Scientific and Technical Information of China (English)

    QU Jin-rong; JIANG Tao; DAI Jian-ping; LI Hai-liang; LUO Jun-peng; LI Shao-wu; AI Lin; JIANG Tian-zi

    2012-01-01

    Background Reliable early prediction response to therapy and time-to-progression (TTP) remain an important goal of high-grade gliomas (HGGs) research.Proton magnetic resonance spectroscopy (1H-MRS) has been applied with variable success in clinical application,and we hypothesize that 1H-MRS in predictive value should perform well as a marker of TTP in patients treated with radiotherapy (RT) after surgery.Methods 1H-MRS was performed before surgery on 25 patients who had undergone resection of HGGs; then the ratios of lipid/creatine (Lip/Cr) and myo-inositol/creatine (ml/Cr) were determined in the solid tumor.RT response was classified as follows:complete resolution (CR),partial response (PR),stable disease (SD),and progressive disease (PD) by comparison of pre-treatment and post-radiotherapy scans.TTP was defined at the time to radiographic progression by MacDonald criteria.Correlation was evaluated between the ratios of Lip/Cr,ml/Cr and treatment response,TTP.The chi-square test and Pearson correlation test were used for data analyses.Results Multivariate analysis revealed that the prognostic value of spectroscopic variables was independent of age,sex,WHO histologic grade,extent of surgery,and Karnofsky score (KPS).The correlation between the ratios of lipid/Cr and TTP was significant (r=0.894,P=0.000),and between the ratios of ml/Cr and TTP was also significant (r=0.891,P=0.000).As predicted,RT response correlated significantly with TTP (r=0.59,P=0.002):median TTP was 49.9 days for patients with PD compared with 202.7 days for SD,208.0 days for PR,and 234.5 days for CR.Conclusion The ratios of Lip/Cr and ml/Cr of the solid tumor region before surgery could provide important information in predicting RT response and TTP in patients with HGGs treated by radiation alone after surgery.

  6. Early time course of N-acetylaspartate, creatine and phosphocreatine, and compounds containing choline in the brain after acute stroke. A proton magnetic resonance spectroscopy study

    DEFF Research Database (Denmark)

    Gideon, P; Henriksen, O; Sperling, B

    1992-01-01

    BACKGROUND AND PURPOSE: The early time course after acute stroke of cerebral N-acetylaspartate, creatine and phosphocreatine, and compounds containing choline was studied in vivo by means of localized water-suppressed proton magnetic resonance spectroscopy. METHODS: Eight patients with acute stroke...... were studied serially in the acute phase, 1 week after, and 2-4 weeks after the onset of clinical symptoms. Ten healthy volunteers served as controls. A stimulated echo (STEAM) sequence was used for measurement of the brain metabolites in a volume of interest located within the infarcted area...

  7. Prognostic value of proton magnetic resonance spectroscopy findings in near drowning patients: reversibility of the early metabolite abnormalities relates with a good outcome

    Energy Technology Data Exchange (ETDEWEB)

    Aragao, Maria de Fatima Vasco; Law, Meng; Prola Netto, Joao; Naidich, Thomas [Mount Sinai School of Medicine, New York, NY (United States). Dept. of Radiology], e-mail: aragao@truenet.com; Valenca, Marcelo Moraes [Federal University of Pernambuco (UFPE), Recife, PE (Brazil). Dept. of Neuropsychiatry and Behavioral Studies

    2009-03-15

    In two children with near drowning hypoxic encephalopathy and normal-appearing structural MRI, acute proton magnetic resonance spectroscopy ({sup 1}H MRS) showed biochemical alterations that correctly indicated prognosis and helped to guide management decisions. Elevation of the lipid-lactate and glutamine-glutamate peaks, on the early (72 hour) {sup 1}H MRS, predicts a poor prognosis. Absence of lipid-lactate and glutamine-glutamate peaks on the early {sup 1}H MRS and reversibility of early mild metabolite abnormalities on follow up examination relates with good outcome. (author)

  8. X-ray magnetic dichroism: from quantitative determination of magnetic moments to imaging of magnetization dynamics; Dichroisme magnetique des rayons X: de la determination quantitative des moments magnetiques a l'imagerie de la dynamique de l'aimantation

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, J

    2006-03-15

    In this document, I use some results of my research activities of the last ten years to show the power of x-ray magnetic dichroism for determining magnetic properties of thin layers, multilayers and nano-structures. The use of sum rules for x-ray dichroism allows a quantitative determination of the spin and orbital contributions to the magnetic moment, for each element of a heterogeneous material separately. Used in a qualitative way, x-ray dichroism allows monitoring the magnetization of the different layers in a multilayer material as a function of applied field. In combination with the temporal structure of synchrotron radiation, it is possible to study fast magnetization reversal with element selectivity, which is important for devices like spin valves and magnetic tunnel junctions. Adding the spatial resolution of a photoelectron emission microscope (PEEM), it becomes possible to study all the details of the fast magnetization reversal in complex magnetic systems. (author)

  9. Quantitative structure-property relationship studies for collision cross sections of 579 singly protonated peptides based on a novel descriptor as molecular graph fingerprint (MoGF)

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Peng [Department of Chemistry, Zhejiang University, Hangzhou 310027 (China) and College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China)], E-mail: ggootc@163.com; Tian Feifei [College of Bioengineering, Chongqing University, Chongqing 400044 (China); Li Zhiliang [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China) and State Key Laboratory of Chemo/Biosensing and Chemometrics, Changsha 410082 (China)], E-mail: ggootc@163.com

    2007-08-10

    Aiming at ion mobility spectrometry (IMS), computer-assisted ion mobility prediction (CAIMP) has been recently developed to simulate and predict diverse IMS behaviors in assistance of mathematics and computer science. Of that, quantitative structure-property relationship (QSPR) plays a vital role, dedicating to predict properties of unknown samples by creating statistical model based on known samples. In QSPR, the key lies in how to transform structural characteristics of target compounds into a group of numerical codes. In consideration that future IMS applications may mainly focus on intricate drug/biological systems, a novel molecular structural characterization method referring to molecular graphic fingerprint (MoGF) is proposed in this paper. In MoGF approach, radical distribution function is employed to map intrinsic interatomic correlations into a coordinate system according to a reasonable sampling interval, thus forming the characteristic graph curve which is rich in information on molecular structural characteristics, possessing of great merits in easy calculation, independent of experiments, large information contents, explicit structural meanings and intuitive expressions, etc. Consequently, MoGF is utilized to QSPR studies on 579 singly protonated peptide collision cross sections, and the constructed partial least square (PLS) regression model is confirmed to be robust and predictable by rigorous both internal and external validations, with statistics as r{sup 2} = 0.991, q{sup 2} = 0.990, RMSEE = 5.526, RMSCV = 5.572, q{sub ext}{sup 2}=0.990, r{sub ext}{sup 2}=0.990, r{sub 0,ext}{sup 2}=0.990, r{sub 0,ext}{sup '2}=0.990, k = 1.003, k' = 0.996 and RMSEP = 5.561, respectively.

  10. Quantitative magnetic resonance imaging in limb-girdle muscular dystrophy 2I

    DEFF Research Database (Denmark)

    Willis, Tracey A; Hollingsworth, Kieren G; Coombs, Anna

    2014-01-01

    -related protein (FKRP) gene were recruited. In each patient, T1-weighted (T1w) imaging was assessed by qualitative grading for 15 individual lower limb muscles and quantitative Dixon imaging was analysed on 14 individual lower limb muscles by region of interest analysis. We described the pattern and appearance......) that the quantitative Dixon technique is an objective quantitative marker of disease and (ii) new observations of gender specific patterns of muscle involvement in LGMD2I....

  11. Proton magnetic resonance spectroscopy assessment of metabolite status of the anterior cingulate cortex in chronic pain patients and healthy controls

    Directory of Open Access Journals (Sweden)

    Ito T

    2017-01-01

    Full Text Available Takahiro Ito,1 Sachiko Tanaka-Mizuno,2,3 Narihito Iwashita,4 Ikuo Tooyama,5 Akihiko Shiino,6 Katsuyuki Miura,1,7 Sei Fukui4 1Department of Public Health, Shiga University of Medical Science, 2Department of Medical Statistics, Shiga University of Medical Science, Otsu, Japan; 3The Center for Data Science Education and Research, Shiga University, Hikone, Japan; 4Department of Anesthesiology, Interdisciplinary Pain Management Center, Shiga University of Medical Science Hospital, 5Molecular Neuroscience Research Center, Shiga University of Medical Science, 6Biomedical MR Science Center, Shiga University of Medical Science, 7Center for Epidemiologic Research in Asia, Shiga University of Medical Science, Otsu, Japan Background: Chronic pain is a common cause of reduced quality of life. Recent studies suggest that chronic pain patients have a different brain neurometabolic status to healthy people. Proton magnetic resonance spectroscopy (1H-MRS can determine the concentrations of metabolites in a specific region of the brain without being invasive. Patients and methods: We recruited 56 chronic pain patients and 60 healthy controls to compare brain metabolic characteristics. The concentrations of glutamic acid (Glu, myo-inositol (Ins, N-acetylaspartate (NAA, Glu + glutamine (Glx, and creatine + phosphocreatine (total creatine [tCr] in the anterior cingulate cortex of participants were measured using 1H-MRS. We used age- and gender-adjusted general linear models and receiver-operating characteristic analyses for this investigation. Patients were also assessed using the Hospital Anxiety and Depression Scale (HADS to reveal the existence of any mental health issues. Results: Our analysis indicates that pain patients have statistically significantly higher levels of Glu/tCr (p=0.039 and Glx/tCr (p<0.001 and lower levels of NAA/tCr than controls, although this did not reach statistical significance (p=0.052. Receiver-operating characteristic analysis

  12. The quantitative measurement of magnetic moments from phase images of nanoparticles and nanostructures – I. Fundamentals

    DEFF Research Database (Denmark)

    Beleggia, Marco; Kasama, Takeshi; Dunin-Borkowski, Rafal E.

    2010-01-01

    An approach that can be used to measure the magnetic moment of a magnetized nanoparticle or nanostructure from an electron-optical phase image is introduced. The measurement scheme is based on integration of the gradient of the measured phase image within a circular boundary that contains...... the structure of interest. The quantity obtained is found to be directly proportional to the magnetic moment of the particle, with a constant of proportionality that does not depend on the particle's shape or magnetization state. The measurement of magnetic moments from both simulated and experimental phase...... images is demonstrated, and strategies are presented that can be utilized to overcome sources of error associated with, for example, the presence of neighboring magnetic particles and the perturbation of the holographic reference wave...

  13. The quantitative measurement of magnetic moments from phase images of nanoparticles and nanostructures-I. Fundamentals

    Energy Technology Data Exchange (ETDEWEB)

    Beleggia, Marco, E-mail: mb@cen.dtu.dk [Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Kasama, Takeshi; Dunin-Borkowski, Rafal E. [Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark)

    2010-04-15

    An approach that can be used to measure the magnetic moment of a magnetized nanoparticle or nanostructure from an electron-optical phase image is introduced. The measurement scheme is based on integration of the gradient of the measured phase image within a circular boundary that contains the structure of interest. The quantity obtained is found to be directly proportional to the magnetic moment of the particle, with a constant of proportionality that does not depend on the particle's shape or magnetization state. The measurement of magnetic moments from both simulated and experimental phase images is demonstrated, and strategies are presented that can be utilized to overcome sources of error associated with, for example, the presence of neighboring magnetic particles and the perturbation of the holographic reference wave.

  14. High-resolution morphologic and ultrashort time-to-echo quantitative magnetic resonance imaging of the temporomandibular joint

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Won C.; Chang, Eric Y.; Biswas, Reni; Statum, Sheronda; Chung, Christine B. [Veterans Administration San Diego Healthcare System, Department of Radiology, San Diego, CA (United States); University of California, San Diego, School of Medicine, Department of Radiology, San Diego, CA (United States); Tafur, Monica; Du, Jiang; Healey, Robert [University of California, San Diego, School of Medicine, Department of Radiology, San Diego, CA (United States); Kwack, Kyu-Sung [Ajou University Medical Center, Department of Radiology, Wonchon-dong, Yeongtong-gu, Gyeonggi-do, Suwon (Korea, Republic of)

    2016-03-15

    To implement high-resolution morphologic and quantitative magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ) using ultrashort time-to-echo (UTE) techniques in cadavers and volunteers. This study was approved by the institutional review board. TMJs of cadavers and volunteers were imaged on a 3-T MR system. High-resolution morphologic and quantitative sequences using conventional and UTE techniques were performed in cadaveric TMJs. Morphologic and UTE quantitative sequences were performed in asymptomatic and symptomatic volunteers. Morphologic evaluation demonstrated the TMJ structures in open- and closed-mouth position. UTE techniques facilitated the visualization of the disc and fibrocartilage. Quantitative UTE MRI was successfully performed ex vivo and in vivo, reflecting the degree of degeneration. There was a difference in the mean UTE T2* values between asymptomatic and symptomatic volunteers. MRI evaluation of the TMJ using UTE techniques allows characterization of the internal structure and quantification of the MR properties of the disc. Quantitative UTE MRI can be performed in vivo with short scan times. (orig.)

  15. Study of the interactions of 13.8 GeV/c protons with the heavy nuclei of the emulsions exposed in magnetic fuel of 170 kgauss; Estudio de las interacciones de protones de 13,8 geV/c con los nucleos pesados de emusiones

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Aleixandre, J. L.

    1967-07-01

    145 stars with N{sub h}>8 produced by the interactions of 13.8 GeV/c protons with Ag and Br nuclei have been analysed. The emulsion stack was irradiated in a 170 K gauss magnetic field. Statistical results concerning the main characteristics of the different particles emitted are given and the energy balance is evaluated. The main features of both 24 GeV/c protons and 17 GeV/c {pi}- interactions are compared with those we have found for 13.8 GeV/c protons interactions. (Author) 27 refs.

  16. Quantum molecular dynamics and molecular interactions studied by NMR and INS Nuclear magnetic resonance; Proton tunnelling; Hydrogen bond

    CERN Document Server

    Jones, N

    2002-01-01

    The wavefunction of a particle extends into the classically forbidden barrier region of the potential energy surface. The consequence of this partial delocalisation is the phenomenon of quantum tunnelling, an effect which enables a particle to penetrate a potential barrier of magnitude greater than the energy of the particle. The tunnelling probability is an exponential function of the particle mass. The effect is therefore an important contribution to the behaviour of light atoms, in particular the proton. The hydrogen bond has long been appreciated to be an essential component of many biological and chemical systems, and the proton transfer reaction in the hydrogen bond is fundamental to many of these processes. The proton behaviour in the hydrogen bonds of benzoic acid, acetylacetone and calix-4-arene has been studied. A variety of techniques, both experimental and computational, were adopted for the study of the three hydrogen bonded systems. The complementary spectroscopic techniques of inelastic neutron...

  17. Quantitative measurements of magnetic polaron binding on acceptors in CdMnTe alloys

    Science.gov (United States)

    Nhung, Tran Hong; Planel, R.

    1983-03-01

    The acceptor binding energy is measured as a function of Temperature and composition in Cd1-x Mnx Te alloys, by time resolved spectroscopy. The Bound magnetic polaron effect is measured and compared with a theory accouting for magnetic saturation and fluctuations.

  18. Assessment of Renal Hemodynamics and Oxygenation by Simultaneous Magnetic Resonance Imaging (MRI) and Quantitative Invasive Physiological Measurements.

    Science.gov (United States)

    Cantow, Kathleen; Arakelyan, Karen; Seeliger, Erdmann; Niendorf, Thoralf; Pohlmann, Andreas

    2016-01-01

    In vivo assessment of renal perfusion and oxygenation under (patho)physiological conditions by means of noninvasive diagnostic imaging is conceptually appealing. Blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) and quantitative parametric mapping of the magnetic resonance (MR) relaxation times T 2* and T 2 are thought to provide surrogates of renal tissue oxygenation. The validity and efficacy of this technique for quantitative characterization of local tissue oxygenation and its changes under different functional conditions have not been systematically examined yet and remain to be established. For this purpose, the development of an integrative multimodality approaches is essential. Here we describe an integrated hybrid approach (MR-PHYSIOL) that combines established quantitative physiological measurements with T 2* (T 2) mapping and MR-based kidney size measurements. Standardized reversible (patho)physiologically relevant interventions, such as brief periods of aortic occlusion, hypoxia, and hyperoxia, are used for detailing the relation between the MR-PHYSIOL parameters, in particular between renal T 2* and tissue oxygenation.

  19. Magnetic Resonance Imaging of Intracranial Hypotension: Diagnostic Value of Combined Qualitative Signs and Quantitative Metrics.

    Science.gov (United States)

    Aslan, Kerim; Gunbey, Hediye Pinar; Tomak, Leman; Ozmen, Zafer; Incesu, Lutfi

    2017-07-13

    The aim of this study was to investigate whether the use of combination quantitative metrics (mamillopontine distance [MPD], pontomesencephalic angle, and mesencephalon anterior-posterior/medial-lateral diameter ratios) with qualitative signs (dural enhancement, subdural collections/hematoma, venous engorgement, pituitary gland enlargements, and tonsillar herniations) provides a more accurate diagnosis of intracranial hypotension (IH). The quantitative metrics and qualitative signs of 34 patients and 34 control subjects were assessed by 2 independent observers. Receiver operating characteristic (ROC) curve was used to evaluate the diagnostic performance of quantitative metrics and qualitative signs, and for the diagnosis of IH, optimum cutoff values of quantitative metrics were found with ROC analysis. Combined ROC curve was measured for the quantitative metrics, and qualitative signs combinations in determining diagnostic accuracy and sensitivity, specificity, and positive and negative predictive values were found, and the best model combination was formed. Whereas MPD and pontomesencephalic angle were significantly lower in patients with IH when compared with the control group (P quantitative metrics, the highest individual distinctive power was MPD with AUC of 0.947. The best accuracy in the diagnosis of IH was obtained by combination of dural enhancement, venous engorgement, and MPD with an AUC of 1.00. This study showed that the combined use of dural enhancement, venous engorgement, and MPD had diagnostic accuracy of 100 % for the diagnosis of IH. Therefore, a more accurate IH diagnosis can be provided with combination of quantitative metrics with qualitative signs.

  20. Magnetic Resonance-based Motion Correction for Quantitative PET in Simultaneous PET-MR Imaging.

    Science.gov (United States)

    Rakvongthai, Yothin; El Fakhri, Georges

    2017-07-01

    Motion degrades image quality and quantitation of PET images, and is an obstacle to quantitative PET imaging. Simultaneous PET-MR offers a tool that can be used for correcting the motion in PET images by using anatomic information from MR imaging acquired concurrently. Motion correction can be performed by transforming a set of reconstructed PET images into the same frame or by incorporating the transformation into the system model and reconstructing the motion-corrected image. Several phantom and patient studies have validated that MR-based motion correction strategies have great promise for quantitative PET imaging in simultaneous PET-MR. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Nuclear magnetic relaxation studies of water in frozen biological tissues. Cross-relaxation effects between protein and bound water protons

    Science.gov (United States)

    Escanyé, J. M.; Canet, D.; Robert, J.

    Water proton longitudinal relaxation has been investigated in frozen mouse tissues including tumors. The nonfreezable water which gives rise to a relatively sharp NMR signal at this temperature (263 K) is identified as water bound to macromolecules. Measurements have been carried out by the nonselective inversion-recovery method at 90 and 6 MHz. Partially selective inversion has been achieved at 90 MHz by the DANTE sequence. The experimental data are analyzed by means of Solomon-type equations. This analysis provides the cross-relaxation term from which the dipolar contribution to water relaxation rate, arising from interactions with macromolecular protons, is calculated. This contribution seems to be dominant. The number of water protons interacting with a given macromolecular proton is found to be of the order of 10. The data at both frequencies can be consistently interpreted in terms of water diffusion, with a characteristic time of about 10 -9 sec. These conclusions are valid for all the tissues investigated here, their relaxation parameters exhibiting only slight differences.

  2. Quantitative 3D breast magnetic resonance imaging fibroglandular tissue analysis and correlation with qualitative assessments: a feasibility study.

    Science.gov (United States)

    Ha, Richard; Mema, Eralda; Guo, Xiaotao; Mango, Victoria; Desperito, Elise; Ha, Jason; Wynn, Ralph; Zhao, Binsheng

    2016-04-01

    The amount of fibroglandular tissue (FGT) has been linked to breast cancer risk based on mammographic density studies. Currently, the qualitative assessment of FGT on mammogram (MG) and magnetic resonance imaging (MRI) is prone to intra and inter-observer variability. The purpose of this study is to develop an objective quantitative FGT measurement tool for breast MRI that could provide significant clinical value. An IRB approved study was performed. Sixty breast MRI cases with qualitative assessment of mammographic breast density and MRI FGT were randomly selected for quantitative analysis from routine breast MRIs performed at our institution from 1/2013 to 12/2014. Blinded to the qualitative data, whole breast and FGT contours were delineated on T1-weighted pre contrast sagittal images using an in-house, proprietary segmentation algorithm which combines the region-based active contours and a level set approach. FGT (%) was calculated by: [segmented volume of FGT (mm(3))/(segmented volume of whole breast (mm(3))] ×100. Statistical correlation analysis was performed between quantified FGT (%) on MRI and qualitative assessments of mammographic breast density and MRI FGT. There was a significant positive correlation between quantitative MRI FGT assessment and qualitative MRI FGT (r=0.809, n=60, Pqualitative MRI FGT assessment and mammographic density assessment (r=0.725, n=60, Pqualitative assessment categories of FGT correlated with the calculated mean quantitative FGT (%) of 4.61% (95% CI, 0-12.3%), 8.74% (7.3-10.2%), 18.1% (15.1-21.1%), 37.4% (29.5-45.3%). Quantitative measures of FGT (%) were computed with data derived from breast MRI and correlated significantly with conventional qualitative assessments. This quantitative technique may prove to be a valuable tool in clinical use by providing computer generated standardized measurements with limited intra or inter-observer variability.

  3. A quantitative magnetic resonance histology atlas of postnatal rat brain development with regional estimates of growth and variability.

    Science.gov (United States)

    Calabrese, Evan; Badea, Alexandra; Watson, Charles; Johnson, G Allan

    2013-05-01

    There has been growing interest in the role of postnatal brain development in the etiology of several neurologic diseases. The rat has long been recognized as a powerful model system for studying neuropathology and the safety of pharmacologic treatments. However, the complex spatiotemporal changes that occur during rat neurodevelopment remain to be elucidated. This work establishes the first magnetic resonance histology (MRH) atlas of the developing rat brain, with an emphasis on quantitation. The atlas comprises five specimens at each of nine time points, imaged with eight distinct MR contrasts and segmented into 26 developmentally defined brain regions. The atlas was used to establish a timeline of morphometric changes and variability throughout neurodevelopment and represents a quantitative database of rat neurodevelopment for characterizing rat models of human neurologic disease. Published by Elsevier Inc.

  4. Quantitative characterization of myocardial infarction by cardiovascular magnetic resonance predicts future cardiovascular events in patients with ischemic cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Pauly John M

    2008-04-01

    Full Text Available Abstract Background Cardiovascular magnetic resonance (CMR can provide quantitative data of the myocardial tissue utilizing high spatial and temporal resolution along with exquisite tissue contrast. Previous studies have correlated myocardial scar tissue with the occurrence of ventricular arrhythmia. This study was conducted to evaluate whether characterization of myocardial infarction by CMR can predict cardiovascular events in patients with ischemic cardiomyopathy (ICM. Results We consecutively studied 86 patients with ICM (LVEF Conclusion Quantification of the scar volume and scar percentage by CMR is superior to LVEDV, LVESV, and LVEF in prognosticating the future likelihood of the development of cardiovascular events in patients with ICM.

  5. The Assessment of Structural Changes in MS Plaques and Normal Appearing White Matter Using Quantitative Magnetization Transfer Imaging (MTI

    Directory of Open Access Journals (Sweden)

    Masoomeh Fooladi

    2007-12-01

    Full Text Available Introduction: Multiple sclerosis (MS is a demyelinating disease of the central nervous system (CNS, affecting mostly young people at a mean age of 30 years. Magnetic resonance imaging (MRI is one of the most specific and sensitive methods in diagnosing and detecting the evolution of multiple sclerosis disease. But it does not have the ability to differentiate between distinct histopathological heterogeneities that occur in MS lesions and brain tissue.Quantitative magnetization transfer imaging (qMTI is a relatively new MRI technique which can be used to examine the pathological processes of the brain parenchyma which occur in MS patients.This quantitative MRI technique can provide more complete information about the extent and nature of the brain tissue destruction in multiple sclerosis, which cannot be detected by conventional MRI. Material and Methods: In this study, twelve patients with relapsing-remitting MS and twelve healthy control subjects underwent conventional MR imaging including: T2-FSE, T1-SE and FLAIR sequences as well as quantitative magnetization transfer imaging. All the focal lesions were identified on T2-weighted images and were classified according to their signal hypointensity on T1-weighted scans. The white matter and MS lesions were segmented using a semi-automated system. MT ratio (MTR histogram analysis was performed for the brain white matter and the average MTR value was calculated for the classified MS lesions. Results: A significant reduction was found in MTR value of the normal appearing white matter (NAWM in patients with relapsing-remitting MS, suggesting that MS is a more diffuse disease, affecting the whole brain tissue. A wide range changes in MTR values can be observed in MS lesions. MTR reduction is correlated with the degree of lesion hypointensity on T1-weighted scans. The lower MTR values of lesions that appear progressively more hypointense on T1-weigted images reflect varying degrees of demyelination and

  6. An integrated device for magnetically-driven drug release and in situ quantitative measurements: Design, fabrication and testing

    Energy Technology Data Exchange (ETDEWEB)

    Bruvera, I.J. [Aragon Institute of Nanoscience (INA), University of Zaragoza, 50018 (Spain); Hernández, R.; Mijangos, C. [Instituto de Ciencia y Tecnología de Polímeros, CSIC, Juan Cierva 3, E-28006 Madrid (Spain); Goya, G.F., E-mail: goya@unizar.es [Aragon Institute of Nanoscience (INA), University of Zaragoza, 50018 (Spain); Condensed Matter Physics Department, Science Faculty, University of Zaragoza, 50009 (Spain)

    2015-03-01

    We have developed a device capable of remote triggering and in situ quantification of therapeutic drugs, based on magnetically-responsive hydrogels of poly (N-isopropylacrylamide) and alginate (PNiPAAm). The heating efficiency of these hydrogels measured by their specific power absorption (SPA) values showed that the values between 100 and 300 W/g of the material were high enough to reach the lower critical solution temperature (LCST) of the polymeric matrix within few minutes. The drug release through application of AC magnetic fields could be controlled by time-modulated field pulses in order to deliver the desired amount of drug. Using B12 vitamin as a concept drug, the device was calibrated to measure amounts of drug released as small as 25(2)×10{sup −9} g, demonstrating the potential of this device for very precise quantitative control of drug release. - Highlights: • A device for magnetically driven drug release was developed and constructed. • Thermally responsive PNiPAAm and Fe3O4 nanoparticles were usedas drug reservoir. • The device allowed repetitive, remote and precisely controlled drug release. • By in situ spectrometry we could detect released drug quantities as small as 25 ng. • Released drug was controlled through magnetic ac field parameters H, f and time.

  7. Origin of (105) Reflection of X-Ray Diffraction and Quantitative Evaluation of Alignment Degree for Sintered Nd-Fe-B Magnets

    Institute of Scientific and Technical Information of China (English)

    HE Ye-Qing; ZHOU Shou-Zeng; ZHANG Zhen-Rong; HAN Bao-Shan

    2001-01-01

    A new method for quantitatively evaluating the alignment degree ofsintered Nd-FeB magnets by x-ray diffraction spectra has been proposed. It has been experimentally revealed that the strong (105) reflection existing in almost all x-ray diffraction spectra of sintered Nd-FeB magnets stems from the misalignment grains whose easy axes are at an angle of 15.5° with respect to the orientated direction of the magnet.

  8. Magnetic resonance imaging of stents. Quantitative in vitro examination at 3 Tesla; Magnetresonanztomographie von Stents. Quantitative MR-Untersuchungen in vitro bei 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Reinhardt, Julia [Neurologische Universitaetsklinik Heidelberg (Germany). Sektion Experimentelle Radiologie; Fachhochschule Jena (Germany). Fachbereich Medizintechnik; Nguyen-Trong, Thien-Hoa; Haehnel, Stefan [Neurologische Universitaetsklinik Heidelberg (Germany). Abt. Neuroradiologie; Bellemann, Matthias E. [Fachhochschule Jena (Germany). Fachbereich Medizintechnik; Heiland, Sabine [Neurologische Universitaetsklinik Heidelberg (Germany). Sektion Experimentelle Radiologie; Neurologische Universitaetsklinik Heidelberg (Germany). Abt. Neuroradiologie

    2009-07-01

    The aim of this study was to qualitatively and quantitatively study MR artifacts of various stents on the basis of in vitro experiments. We were particularly interested whether sequence type and orientation of the stent with respect to the static magnetic field influences the artifact. We examined 18 stents of different material (nitinol, stainless steel, cobalt alloy), different design of the stent meshes (AccuLink, OmniLink, DynaLink, Xact, Protoge, Wallstent Monorail), different diameter (5-10 mm) and different length (18-58 mm) with a turbo spin echo (TSE), a 2D-fast low angle shot (FLASH) and a 3D-FLASH sequence. The MR images were examined qualitatively with respect to possible artifacts. Furthermore we examined the MR data quantitatively: The contrast-noise-ratio (CNR) was determined both within the stent and outside (within the tube); based on these values we calculated the transparency factor P, furthermore we calculated the apparent vascular lumen within the tube and within the stent. The stents made of stainless steel and cobalt alloy displayed severe susceptibility artifacts. Therefore the vessel lumen within the stent could not be assessed. The nitinol stents showed different artifact patterns: The AccuLink and DynaLink stents showed less artifacts compared to the Xact and Protoge stents. Besides the susceptibility artifacts we found artifacts due to RF shielding by the stent mesh, particularly in TSE sequences. A MR control of patients after stenting is possible and may yield diagnostic information when using the AccuLink or DynaLink stents. However, it is important to make sure that the stent is MR safe for the field strength used for the examination. (orig.)

  9. Proton Radiography Imager:Generates Synthetic Proton Radiographs

    Energy Technology Data Exchange (ETDEWEB)

    2017-09-12

    ProRad is a computer program that is used to generate synthetic images of proton (or other charged particles) radiographs. The proton radiographs arc images that arc obtained by sending energetic protons (or electrons or positrons, for example) through 11 plasma where electric and/or magnetic fields alter the particles trajectory, Dnd the variations me imaged on RC film, image plate, or equivalent

  10. Quantitative separation of CEST effect from magnetization transfer and spillover effects by Lorentzian-line-fit analysis of z-spectra

    Science.gov (United States)

    Zaiß, Moritz; Schmitt, Benjamin; Bachert, Peter

    2011-08-01

    Chemical exchange saturation transfer (CEST) processes in aqueous systems are quantified by evaluation of z-spectra, which are obtained by acquisition of the water proton signal after selective RF presaturation at different frequencies. When saturation experiments are performed in vivo, three effects are contributing: CEST, direct water saturation (spillover), and magnetization transfer (MT) mediated by protons bound to macromolecules and bulk water molecules. To analyze the combined saturation a new analytical model is introduced which is based on the weak-saturation-pulse (WSP) approximation. The model combines three single WSP approaches to a general model function. Simulations demonstrated the benefits and constraints of the model, in particular the capability of the model to reproduce the ideal proton transfer rate (PTR) and the conventional MT rate for moderate spillover effects (up to 50% direct saturation at CEST-resonant irradiation). The method offers access to PTR from z-spectra data without further knowledge of the system, but requires precise measurements with dense saturation frequency sampling of z-spectra. PTR is related to physical parameters such as concentration, transfer rates and thereby pH or temperature of tissue, using either exogenous contrast agents (PARACEST, DIACEST) or endogenous agents such as amide protons and -OH protons of small metabolites.

  11. Closed-form solution of the convolution integral in the magnetic resonance dispersion model for quantitative assessment of angiogenesis.

    Science.gov (United States)

    Turco, S; Janssen, A J E M; Lavini, C; de la Rosette, J J; Wijkstra, H; Mischi, M

    2014-01-01

    Prostate cancer (PCa) diagnosis and treatment is still limited due to the lack of reliable imaging methods for cancer localization. Based on the fundamental role played by angiogenesis in cancer growth and development, several dynamic contrast enhanced (DCE) imaging methods have been developed to probe tumor angiogenic vasculature. In DCE magnetic resonance imaging (MRI), pharmacokinetic modeling allows estimating quantitative parameters related to the physiology underlying tumor angiogenesis. In particular, novel magnetic resonance dispersion imaging (MRDI) enables quantitative assessment of the microvascular architecture and leakage, by describing the intravascular dispersion kinetics of an extravascular contrast agent with a dispersion model. According to this model, the tissue contrast concentration at each voxel is given by the convolution between the intravascular concentration, described as a Brownian motion process according to the convective-dispersion equation, with the interstitium impulse response, represented by a mono-exponential decay, and describing the contrast leakage in the extravascular space. In this work, an improved formulation of the MRDI method is obtained by providing an analytical solution for the convolution integral present in the dispersion model. The performance of the proposed method was evaluated by means of dedicated simulations in terms of estimation accuracy, precision, and computation time. Moreover, a preliminary clinical validation was carried out in five patients with proven PCa. The proposed method allows for a reduction by about 40% of computation time without any significant change in estimation accuracy and precision, and in the clinical performance.

  12. Quantitative review of the efficacy of slow-frequency magnetic brain stimulation in major depressive disorder

    NARCIS (Netherlands)

    Schutter, D.J.L.G.

    2010-01-01

    Background Slow-frequency repetitive transcranial magnetic stimulation (rTMS) to the frontal cortex has been suggested as a safer and better tolerable alternative to fast-frequency rTMS in the treatment of major depressive disorder (MDD). The aim of the present study was to examine the efficacy of s

  13. Cardiovascular magnetic resonance myocardial feature tracking detects quantitative wall motion during dobutamine stress.

    NARCIS (Netherlands)

    Schuster, A.; Kutty, S.; Padiyath, A.; Parish, V.; Gribben, P.; Danford, D.A.; Makowski, M.R.; Bigalke, B.; Beerbaum, P.B.J.; Nagel, E.

    2011-01-01

    BACKGROUND: Dobutamine stress cardiovascular magnetic resonance (DS-CMR) is an established tool to assess hibernating myocardium and ischemia. Analysis is typically based on visual assessment with considerable operator dependency. CMR myocardial feature tracking (CMR-FT) is a recently introduced tec

  14. Multiharmonic rf feedforward system for compensation of beam loading and periodic transient effects in magnetic-alloy cavities of a proton synchrotron

    Science.gov (United States)

    Tamura, Fumihiko; Ohmori, Chihiro; Yamamoto, Masanobu; Yoshii, Masahito; Schnase, Alexander; Nomura, Masahiro; Toda, Makoto; Shimada, Taihei; Hasegawa, Katsushi; Hara, Keigo

    2013-05-01

    Beam loading compensation is a key for acceleration of a high intensity proton beam in the main ring (MR) of the Japan Proton Accelerator Research Complex (J-PARC). Magnetic alloy loaded rf cavities with a Q value of 22 are used to achieve high accelerating voltages without a tuning bias loop. The cavity is driven by a single harmonic (h=9) rf signal while the cavity frequency response also covers the neighbor harmonics (h=8,10). Therefore the wake voltage induced by the high intensity beam consists of the three harmonics, h=8,9,10. The beam loading of neighbor harmonics is the source of periodic transient effects and a possible source of coupled bunch instabilities. In the article, we analyze the wake voltage induced by the high intensity beam. We employ the rf feedforward method to compensate the beam loading of these three harmonics (h=8,9,10). The full-digital multiharmonic feedforward system was developed for the MR. We describe the system architecture and the commissioning methodology of the feedforward patterns. The commissioning of the feedforward system has been performed by using high intensity beams with 1.0×1014 proteins per pulse. The impedance seen by the beam is successfully reduced and the longitudinal oscillations due to the beam loading are reduced. By the beam loading compensation, stable high power beam operation is achieved. We also report the reduction of the momentum loss during the debunching process for the slow extraction by the feedforward.

  15. Manufacture and Testing of a High Field Gradient Magnetic Fractionation System for Quantitative Detection of Plasmodium falciparum Gametocytes

    Science.gov (United States)

    Karl, Stephan; Woodward, Robert C.; Davis, Timothy M. E.; St. Pierre, Tim G.

    2010-12-01

    Plasmodium falciparum is the most dangerous of the human malaria parasite species and accounts for millions of clinical episodes of malaria each year in tropical countries. The pathogenicity of Plasmodium falciparum is a result of its ability to infect erythrocytes where it multiplies asexually over 48 h or develops into sexual forms known as gametocytes. If sufficient male and female gametocytes are taken up by a mosquito vector, it becomes infectious. Therefore, the presence and density of gametocytes in human blood is an important indicator of human-to-mosquito transmission of malaria. Recently, we have shown that high field gradient magnetic fractionation improves gametocyte detection in human blood samples. Here we present two important new developments. Firstly we introduce a quantitative approach to replace the previous qualitative method and, secondly, we describe a novel method that enables cost-effective production of the magnetic fractionation equipment required to carry out gametocyte quantification. We show that our custom-made magnetic fractionation equipment can deliver results with similar sensitivity and convenience but for a small fraction of the cost.

  16. Multicavity proton cyclotron accelerator

    Directory of Open Access Journals (Sweden)

    J. L. Hirshfield

    2002-08-01

    Full Text Available A mechanism for acceleration of protons is described, in which energy gain occurs near cyclotron resonance as protons drift through a sequence of rotating-mode TE_{111} cylindrical cavities in a strong nearly uniform axial magnetic field. Cavity resonance frequencies decrease in sequence from one another with a fixed frequency interval Δf between cavities, so that synchronism can be maintained between the rf fields and proton bunches injected at intervals of 1/Δf. An example is presented in which a 122 mA, 1 MeV proton beam is accelerated to 961 MeV using a cascade of eight cavities in an 8.1 T magnetic field, with the first cavity resonant at 120 MHz and with Δf=8 MHz. Average acceleration gradient exceeds 40 MV/m, average effective shunt impedance is 223 MΩ/m, but maximum surface field in the cavities does not exceed 7.2 MV/m. These features occur because protons make many orbital turns in each cavity and thus experience acceleration from each cavity field many times. Longitudinal and transverse stability appear to be intrinsic properties of the acceleration mechanism, and an example to illustrate this is presented. This acceleration concept could be developed into a proton accelerator for a high-power neutron spallation source, such as that required for transmutation of nuclear waste or driving a subcritical fission burner, provided a number of significant practical issues can be addressed.

  17. In-Vivo Proton Magnetic Resonance Spectroscopy of 2-Hydroxyglutarate in Isocitrate Dehydrogenase-Mutated Gliomas: A Technical Review for Neuroradiologists

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyeonjin [Department of Radiology, Seoul National University Hospital, Seoul 03080 (Korea, Republic of); Department of Biomedical Sciences, Seoul National University, Seoul 03087 (Korea, Republic of); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul 03080 (Korea, Republic of); Kim, Sungjin [Department of Radiology, Seoul National University Hospital, Seoul 03080 (Korea, Republic of); Lee, Hyeong Hun; Heo, Hwon [Department of Biomedical Sciences, Seoul National University, Seoul 03087 (Korea, Republic of)

    2016-11-01

    The diagnostic and prognostic potential of an onco-metabolite, 2-hydroxyglutarate (2HG) as a proton magnetic resonance spectroscopy (1H-MRS) detectable biomarker of the isocitrate dehydrogenase (IDH)-mutated (IDH-MT) gliomas has drawn attention of neuroradiologists recently. However, due to severe spectral overlap with background signals, quantification of 2HG can be very challenging. In this technical review for neuroradiologists, first, the biochemistry of 2HG and its significance in the diagnosis of IDH-MT gliomas are summarized. Secondly, various 1H-MRS methods used in the previous studies are outlined. Finally, wereview previous in vivo studies, and discuss the current status of 1H-MRS in the diagnosis of IDH-MT gliomas.

  18. In-Vivo proton magnetic resonance spectroscopy of 2-Hydroxyglutarate in isocitrate dehydrogenase-mutated gliomas: A technical review for neuroradiologists

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyeon Jin; Kim, Sung Jin [Dept. of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of); Lee, Hyeong Hun; Heo, Hwon [Dept. of Biomedical Sciences, Seoul National University, Seoul (Korea, Republic of)

    2016-09-15

    The diagnostic and prognostic potential of an onco-metabolite, 2-hydroxyglutarate (2HG) as a proton magnetic resonance spectroscopy (1H-MRS) detectable biomarker of the isocitrate dehydrogenase (IDH)-mutated (IDH-MT) gliomas has drawn attention of neuroradiologists recently. However, due to severe spectral overlap with background signals, quantification of 2HG can be very challenging. In this technical review for neuroradiologists, first, the biochemistry of 2HG and its significance in the diagnosis of IDH-MT gliomas are summarized. Secondly, various 1H-MRS methods used in the previous studies are outlined. Finally, were view previous in vivo studies, and discuss the current status of 1H-MRS in the diagnosis of IDH-MT gliomas.

  19. QUANTITATIVE MAGNETIC RESONANCE IMAGING OF ARTICULAR CARTILAGE AND ITS CLINICAL APPLICATIONS

    Science.gov (United States)

    Li, Xiaojuan; Majumdar, Sharmila

    2013-01-01

    Cartilage is one of the most essential tissues for healthy joint function and is compromised in degenerative and traumatic joint diseases. There have been tremendous advances during the past decade using quantitative MRI techniques as a non-invasive tool for evaluating cartilage, with a focus on assessing cartilage degeneration during osteoarthritis (OA). In this review, after a brief overview of cartilage composition and degeneration, we discuss techniques that grade and quantify morphologic changes as well as the techniques that quantify changes in the extracellular matrix. The basic principles, in vivo applications, advantages and challenges for each technique are discussed. Recent studies using the OA Initiative (OAI) data are also summarized. Quantitative MRI provides non-invasive measures of cartilage degeneration at the earliest stages of joint degeneration, which is essential for efforts towards prevention and early intervention in OA. PMID:24115571

  20. Influence of the magnetic field on the density distribution of solar wind protons and cometary ions in the shock layer ahead of cometary ionospheres

    Science.gov (United States)

    Baranov, V. B.; Alexashov, D. B.

    2017-02-01

    The "mass loading" of the solar wind by cometary ions produced by the photoionization of neutral molecules outflowing from the cometary nucleus plays a major role in the interaction of the solar wind with cometary atmospheres. In particular, this process leads to a decrease in the solar wind velocity with a transition from supersonic velocities to subsonic ones through the bow shock. The so-called single-fluid approximation, in which the interacting plasma flows are considered as a single fluid, is commonly used in modeling such an interaction. However, it is occasionally necessary to know the distribution of parameters for the components of the interacting plasma flows. For example, when the flow of the cometary dust component in the interplanetary magnetic field is considered, the dust particle charge, which depends significantly on the composition of the surrounding plasma, needs to be known. In this paper, within the framework of a three-dimensional magnetohydrodynamic model of the solar wind flow around cometary ionospheres, we have managed to separately obtain the density distributions of solar wind protons and cometary ions between the bow shock and the cometary ionopause (in the shock layer). The influence of the interplanetary magnetic field on the position of the point of intersection between the densities with the formation of a region near the ionopause where the proton density is essentially negligible compared to the density of cometary ions is investigated. Such a region was experimentally detected by the Vega-2 spacecraft when investigating Comet Halley in March 1986. The results of the model considered below are compared with some experimental data obtained by the Giotto spacecraft under the conditions of flow around Comets Halley and Grigg-Skjellerup in 1986 and 1992, respectively. Unfortunately, our results of calculations on Comet Churyumov-Gerasimenko are only predictive in character, because the trajectory of the Rosetta spacecraft, which

  1. 7T Proton Magnetic Resonance Spectroscopy of Gamma-Aminobutyric Acid, Glutamate, and Glutamine Reveals Altered Concentrations in Patients With Schizophrenia and Healthy Siblings.

    Science.gov (United States)

    Thakkar, Katharine N; Rösler, Lara; Wijnen, Jannie P; Boer, Vincent O; Klomp, Dennis W J; Cahn, Wiepke; Kahn, René S; Neggers, Sebastiaan F W

    2017-03-15

    The N-methyl-D-aspartate receptor hypofunction model of schizophrenia predicts dysfunction in both glutamatergic and gamma-aminobutyric acidergic (GABAergic) transmission. We addressed this hypothesis by measuring GABA, glutamate, glutamine, and the sum of glutamine plus glutamate concentrations in vivo in patients with schizophrenia using proton magnetic resonance spectroscopy at 7T, which allows separation of metabolites that would otherwise overlap at lower field strengths. In addition, we investigated whether altered levels of GABA, glutamate, glutamine, and the sum of glutamine plus glutamate reflect genetic vulnerability to schizophrenia by including healthy first-degree relatives. Proton magnetic resonance spectroscopy at 7T was performed in 21 patients with chronic schizophrenia who were taking medication, 23 healthy first-degree relatives of patients with schizophrenia, and 24 healthy nonrelatives. Glutamate, glutamine, and GABA were measured cortically and subcortically in bilateral basal ganglia and occipital cortex. Patients with schizophrenia had reduced cortical GABA compared with healthy relatives and the combined sample of healthy relatives and healthy nonrelatives, suggesting that altered GABAergic systems in schizophrenia are associated with either disease state or medication effects. Reduced cortical glutamine relative to healthy control subjects was observed in patients with schizophrenia and the combined sample of healthy relatives and patients with schizophrenia, suggesting that altered glutamatergic metabolite levels are associated with illness liability. No group differences were found in the basal ganglia. Taken together, these findings are consistent with alterations in GABAergic and glutamatergic systems in patients with schizophrenia and provide novel insights into these systems in healthy relatives. Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  2. Comparative analysis of fecal fat quantitation via nuclear magnetic resonance spectroscopy (1H NMR) and gravimetry.

    Science.gov (United States)

    Korpi-Steiner, Nichole L; Ward, Jennie N; Kumar, Vivek; McConnell, Joseph P

    2009-02-01

    Fecal-fat is typically measured by extracting lipid from homogenized feces with subsequent gravimetric/titrimetric analyses that are time-consuming and involve toxic solvents. Accordingly, an efficient and more safe method to quantitate fecal-fat is needed. The present objective was to adapt CEM SmartTrac technology (i.e. (1)H NMR) to rapidly (fecal-fat and compare (1)H NMR and gravimetric performance characteristics. (1)H NMR and gravimetric measurements of stool-fat were conducted using excess stool samples (72 h collection; n=107) homogenized to semi-liquid consistency prior to analyses. The (1)H NMR method demonstrated acceptable linearity (R(2)=0.9999) and recovery (mean=105%) with imprecision (intra-assay CV=1.2-6.5%; inter-assay CV=1.8-5.8%) comparable to or better than gravimetry (intra-assay CV=1.0-17.2%; inter-assay CV=3.8-6.5%). Excellent correlation between fecal-fat quantitation by (1)H NMR and gravimetry (n=107; R(2)=0.983; y=1.0173x-0.6859) was exhibited; moreover, (1)H NMR demonstrated good sensitivity (92.3%), specificity (94.5%), negative-predictive value (92.9%) and positive-predictive value (94.1%) for malabsorption using the reference cut-off of fat/24 h. These data demonstrate that (1)H NMR permits rapid and safe quantitation of fecal-fat while maintaining acceptable performance characteristics, thereby supporting the utility of (1)H NMR as an alternative method to gravimetry for fecal-fat quantitation.

  3. Proton Therapy

    Science.gov (United States)

    ... IMRT) Brain Tumor Treatment Brain Tumors Prostate Cancer Lung Cancer Treatment Lung Cancer Head and Neck Cancer Images related to Proton Therapy Videos related to Proton Therapy Sponsored by Please ...

  4. Quantitative ATP synthesis in human liver measured by localized 31P spectroscopy using the magnetization transfer experiment.

    Science.gov (United States)

    Schmid, A I; Chmelík, M; Szendroedi, J; Krssák, M; Brehm, A; Moser, E; Roden, M

    2008-06-01

    The liver plays a central role in intermediate metabolism. Accumulation of liver fat (steatosis) predisposes to various liver diseases. Steatosis and abnormal muscle energy metabolism are found in insulin-resistant and type-2 diabetic states. To examine hepatic energy metabolism, we measured hepatocellular lipid content, using proton MRS, and rates of hepatic ATP synthesis in vivo, using the 31P magnetization transfer experiment. A suitable localization scheme was developed and applied to the measurements of longitudinal relaxation times (T1) in six healthy volunteers and the ATP-synthesis experiment in nine healthy volunteers. Liver 31P spectra were modelled and quantified successfully using a time domain fit and the AMARES (advanced method for accurate, robust and efficient spectral fitting of MRS data with use of prior knowledge) algorithm describing the essential components of the dataset. The measured T1 relaxation times are comparable to values reported previously at lower field strengths. All nine subjects in whom saturation transfer was measured had low hepatocellular lipid content (1.5 +/- 0.2% MR signal; mean +/- SEM). The exchange rate constant (k) obtained was 0.30 +/- 0.02 s(-1), and the rate of ATP synthesis was 29.5 +/- 1.8 mM/min. The measured rate of ATP synthesis is about three times higher than in human skeletal muscle and human visual cortex, but only about half of that measured in perfused rat liver. In conclusion, 31P MRS at 3 T provides sufficient sensitivity to detect magnetization transfer effects and can therefore be used to assess ATP synthesis in human liver.

  5. Quantitative sodium MR imaging of native versus transplanted kidneys using a dual-tuned proton/sodium ({sup 1}H/{sup 23}Na) coil: initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Chan Hong; Furlan, Alessandro [University of Pittsburgh, Department of Radiology, Pittsburgh, PA (United States); Kim, Jung-Hwan; Bae, Kyongtae Ty [University of Pittsburgh, Department of Radiology, Pittsburgh, PA (United States); University of Pittsburgh, Department of Bioengineering, Pittsburgh, PA (United States); Zhao, Tiejun [MR R and D Collaborations, Siemens Medical Solutions USA, Inc, Pittsburgh, PA (United States); Shapiro, Ron [Thomas E. Starzl Transplantation Institute, Department of Surgery, Pittsburgh, PA (United States)

    2014-06-15

    To compare sodium ({sup 23}Na) characteristics between native and transplanted kidneys using dual-tuned proton ({sup 1}H)/sodium MRI. Six healthy volunteers and six renal transplant patients (3 normal function, 3 acute allograft rejection) were included. Proton/sodium MRI was obtained at 3 T using a dual-tuned coil. Signal to noise ratio (SNR), sodium concentration ([{sup 23}Na]) and cortico-medullary sodium gradient (CMSG) were measured. Reproducibility of [{sup 23}Na] measurement was also tested. SNR, [{sup 23}Na] and CMSG of the native and transplanted kidneys were compared. Proton and sodium images of kidneys were successfully acquired. SNR and [{sup 23}Na] measurements of the native kidneys were reproducible at two different sessions. [{sup 23}Na] and CMSG of the transplanted kidneys was significantly lower than those of the native kidneys: 153.5 ± 11.9 vs. 192.9 ± 9.6 mM (P = 0.002) and 8.9 ± 1.5 vs. 10.5 ± 0.9 mM/mm (P = 0.041), respectively. [{sup 23}Na] and CMSG of the transplanted kidneys with normal function vs. acute rejection were not statistically different. Sodium quantification of kidneys was reliably performed using proton/sodium MRI. [{sup 23}Na] and CMSG of the transplanted kidneys were lower than those of the native kidneys, but without a statistically significant difference between patients with or without renal allograft rejection. (orig.)

  6. A quantitative study of particle size effects in the magnetorelaxometry of magnetic nanoparticles using atomic magnetometry

    Energy Technology Data Exchange (ETDEWEB)

    Dolgovskiy, V. [Physics Department, University of Fribourg, CH-1700 Fribourg (Switzerland); Lebedev, V., E-mail: victor.lebedev@unifr.ch [Physics Department, University of Fribourg, CH-1700 Fribourg (Switzerland); Colombo, S.; Weis, A. [Physics Department, University of Fribourg, CH-1700 Fribourg (Switzerland); Michen, B.; Ackermann-Hirschi, L. [Adolphe Merkle Institute, University of Fribourg, CH-1700 Fribourg (Switzerland); Petri-Fink, A. [Adolphe Merkle Institute, University of Fribourg, CH-1700 Fribourg (Switzerland); Chemistry Department, University of Fribourg, CH-1700 Fribourg (Switzerland)

    2015-04-01

    The discrimination of immobilised superparamagnetic iron oxide nanoparticles (SPIONs) against SPIONs in fluid environments via their magnetic relaxation behaviour is a powerful tool for bio-medical imaging. Here we demonstrate that a gradiometer of laser-pumped atomic magnetometers can be used to record accurate time series of the relaxing magnetic field produced by pre-polarised SPIONs. We have investigated dry in vitro maghemite nanoparticle samples with different size distributions (average radii ranging from 14 to 21 nm) and analysed their relaxation using the Néel–Brown formalism. Fitting our model function to the magnetorelaxation (MRX) data allows us to extract the anisotropy constant K and the saturation magnetisation M{sub S} of each sample. While the latter was found not to depend on the particle size, we observe that K is inversely proportional to the (time- and size-) averaged volume of the magnetised particle fraction. We have identified the range of SPION sizes that are best suited for MRX detection considering our specific experimental conditions and sample preparation technique. - Highlights: • We studied magnetorelaxation of magnetic nanoparticles using atomic magnetometers. • We show that atomic magnetometers yield high precision MRX data. • The observed magnetorelaxation is well described by the moment superposition model. • Model fits allow extraction of nanoparticle material parameters of six samples. • All samples exhibit an unexpected size-dependent anisotropy constant.

  7. In vivo proton observed carbon edited (POCE) (13) C magnetic resonance spectroscopy of the rat brain using a volumetric transmitter and receive-only surface coil on the proton channel.

    Science.gov (United States)

    Kumaragamage, Chathura; Madularu, Dan; Mathieu, Axel P; De Feyter, Henk; Rajah, M Natasha; Near, Jamie

    2017-05-12

    In vivo carbon-13 ((13) C) MR spectroscopy (MRS) is capable of measuring energy metabolism and neuroenergetics, noninvasively in the brain. Indirect ((1) H-[(13) C]) MRS provides sensitivity benefits compared with direct (13) C methods, and normally includes a (1) H surface coil for both localization and signal reception. The aim was to develop a coil platform with homogenous B1+ and use short conventional pulses for short echo time proton observed carbon edited (POCE) MRS. A (1) H-[(13) C] MRS coil platform was designed with a volumetric resonator for (1) H transmit, and surface coils for (1) H reception and (13) C transmission. The Rx-only (1) H surface coil nullifies the requirement for a T/R switch before the (1) H preamplifier; the highpass filter and preamplifier can be placed proximal to the coil, thus minimizing sensitivity losses inherent with POCE-MRS systems described in the literature. The coil platform was evaluated with a PRESS-POCE sequence (TE = 12.6 ms) on a rat model. The coil provided excellent localization, uniform spin nutation, and sensitivity. (13) C labeling of Glu-H4 and Glx-H3 peaks, and the Glx-H2 peaks were observed approximately 13 and 21 min following the infusion of 1-(13) C glucose, respectively. A convenient and sensitive platform to study energy metabolism and neurotransmitter cycling is presented. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  8. Proton Decay

    OpenAIRE

    Hikosaka, Koki

    2002-01-01

    We discuss the status of supersymmetric grand unified theories [SUSY GUTs] with regards to the observation of proton decay. In this talk we focus on SUSY GUTs in 4 dimensions. We outline the major theoretical uncertainties present in the calculation of the proton lifetime and then present our best estimate of an absolute upper bound on the predicted proton lifetime. Towards the end, we consider some new results in higher dimensional GUTs and the ramifications for proton decay.

  9. Quantitative chemical exchange saturation transfer (qCEST) MRI - omega plot analysis of RF-spillover-corrected inverse CEST ratio asymmetry for simultaneous determination of labile proton ratio and exchange rate.

    Science.gov (United States)

    Wu, Renhua; Xiao, Gang; Zhou, Iris Yuwen; Ran, Chongzhao; Sun, Phillip Zhe

    2015-03-01

    Chemical exchange saturation transfer (CEST) MRI is sensitive to labile proton concentration and exchange rate, thus allowing measurement of dilute CEST agent and microenvironmental properties. However, CEST measurement depends not only on the CEST agent properties but also on the experimental conditions. Quantitative CEST (qCEST) analysis has been proposed to address the limitation of the commonly used simplistic CEST-weighted calculation. Recent research has shown that the concomitant direct RF saturation (spillover) effect can be corrected using an inverse CEST ratio calculation. We postulated that a simplified qCEST analysis is feasible with omega plot analysis of the inverse CEST asymmetry calculation. Specifically, simulations showed that the numerically derived labile proton ratio and exchange rate were in good agreement with input values. In addition, the qCEST analysis was confirmed experimentally in a phantom with concurrent variation in CEST agent concentration and pH. Also, we demonstrated that the derived labile proton ratio increased linearly with creatine concentration (P exchange rate followed a dominantly base-catalyzed exchange relationship (P exchange rate in a relatively complex in vitro CEST system.

  10. Rapid spin-lattice relaxation time mapping incorporating flip angle calibration in quantitative magnetic resonance imaging

    Institute of Scientific and Technical Information of China (English)

    Zhongliang Zu; Qi Liu; Yanming Yu; Song Gao; Shanglian Bao

    2008-01-01

    Driven equilibrium single pulse observation of T1(DESPOT1)is a rapid spin-lattice relaxation constant(T1)mapping technique in magnetic resonance imaging(MRI).However,DESPOT1 is very sensitive to flip angle(FA)inhomogeneity,resulting in T1 inaccuracy.Here,a five-point DESPOTl method is proposed to reduce the sensitivity to FA inhomogeneity through FA measurement and calibra-tion.Phantom and in vivo experiments are performed to validate the technique.As a result.a rapid and accurate T1 mapping is acquired by using the proposed five-point DESPOT1 method.

  11. Quantitative Evaluation of Left Ventricular Wall Motion in Patient with Coronary Artery Bypass Grafting Using Magnetic Resonance Tagging Technique

    Science.gov (United States)

    Inaba, Tadashi; Nakano, Takahiro; Tsutsumi, Masakazu; Kawasaki, Shingo; Kinosada, Yasutomi; Tokuda, Masataka

    Left ventricular wall motions during systole were investigated from a mechanical perspective by using a magnetic resonance tagging technique. Subjects were 7 patients with coronary artery bypass grafting (CABG). First, by analyzing strain in the left ventricular wall, cardiac contractility was evaluated in the patients with CABG. Next, by calculating displacement in the myocardial wall, paradoxical movements following CABG were quantitatively evaluated. Strain analysis showed local decreases in circumferential strain in 4 of 7 subjects. The results of displacement analysis clarified that following CABG, the degree of radial displacement was small in the septal wall and large in the lateral wall, and circumferential displacement towards the septal wall occurred in the anterior and posterior walls. Since this behavior was seen in both reduced and normal cardiac contractility groups, paradoxical movements in the present patients were not caused by reduced cardiac contractility, but rather by rigid-body motion of the entire heart.

  12. 智能定量充磁机的设计%The Design of an Intelligent Quantitatively Magnetizing Machine

    Institute of Scientific and Technical Information of China (English)

    刘英

    2001-01-01

    介绍了智能定量充磁机的基本工作原理及设计思想、硬件结构、软件流程框图。该机功能强、操作简单、智能化程度高、充磁效率高,具有良好的工程应用前景。%The design of an intelligent quantitatively magnetizing machine is introduced in the paper, about its basic principle, hardware construction and software flow chart. It has many advantages such as strive functions, easy operating, intelligent and high efficiency, and is good applicable in practical engineering.

  13. A Preliminary Application of Magnetic Resonance Spectroscopy for Quantitatively Assessing Hepatic Fat and the Efficacy of Anti-obesity Therapy

    Directory of Open Access Journals (Sweden)

    Hyunseung Lee

    2010-11-01

    Full Text Available Alcoholic and non-alcoholic fatty liver diseases cause insulin resistance and may develop into metabolic diseases such as steatohepatitis or type II diabetes. Standard histopathological examinations are routinely used to measure hepatic fat in order to assess and treat liver diseases, but this method is invasive, complicated, and time-consuming. Here, we present a noninvasive technique, localized magnetic resonance spectroscopy (MRS, for quantitatively measuring hepatic fat in vivo and in situ. This method allowed us to create a relatively high-resolution time series from the same mouse. Further, it enabled us to examine the efficacy of cryptotanshinone (Ct treatment in male mice with non-alcoholic fatty liver disease; MRS clearly showed that mice treated with Ct experienced a dramatic reduction in hepatic fat content compared with control mice. Thus, the localized MRS technique shows promise as a tool for in vivo assessments of drug efficacy against liver fat diseases and for early-stage disease prevention

  14. Multimodal quantitative magnetic resonance imaging of thalamic development and aging across the human lifespan: implications to neurodegeneration in multiple sclerosis.

    Science.gov (United States)

    Hasan, Khader M; Walimuni, Indika S; Abid, Humaira; Frye, Richard E; Ewing-Cobbs, Linda; Wolinsky, Jerry S; Narayana, Ponnada A

    2011-11-16

    The human brain thalami play essential roles in integrating cognitive, sensory, and motor functions. In multiple sclerosis (MS), quantitative magnetic resonance imaging (qMRI) measurements of the thalami provide important biomarkers of disease progression, but late development and aging confound the interpretation of data collected from patients over a wide age range. Thalamic tissue volume loss due to natural aging and its interplay with lesion-driven pathology has not been investigated previously. In this work, we used standardized thalamic volumetry combined with diffusion tensor imaging, T2 relaxometry, and lesion mapping on large cohorts of controls (N = 255, age range = 6.2-69.1 years) and MS patients (N = 109, age range = 20.8-68.5 years) to demonstrate early age- and lesion-independent thalamic neurodegeneration.

  15. The acellular matrix (ACM) for bladder tissue engineering: A quantitative magnetic resonance imaging study.

    Science.gov (United States)

    Cheng, Hai-Ling Margaret; Loai, Yasir; Beaumont, Marine; Farhat, Walid A

    2010-08-01

    Bladder acellular matrices (ACMs) derived from natural tissue are gaining increasing attention for their role in tissue engineering and regeneration. Unlike conventional scaffolds based on biodegradable polymers or gels, ACMs possess native biomechanical and many acquired biologic properties. Efforts to optimize ACM-based scaffolds are ongoing and would be greatly assisted by a noninvasive means to characterize scaffold properties and monitor interaction with cells. MRI is well suited to this role, but research with MRI for scaffold characterization has been limited. This study presents initial results from quantitative MRI measurements for bladder ACM characterization and investigates the effects of incorporating hyaluronic acid, a natural biomaterial useful in tissue-engineering and regeneration. Measured MR relaxation times (T(1), T(2)) and diffusion coefficient were consistent with increased water uptake and glycosaminoglycan content observed on biochemistry in hyaluronic acid ACMs. Multicomponent MRI provided greater specificity, with diffusion data showing an acellular environment and T(2) components distinguishing the separate effects of increased glycosaminoglycans and hydration. These results suggest that quantitative MRI may provide useful information on matrix composition and structure, which is valuable in guiding further development using bladder ACMs for organ regeneration and in strategies involving the use of hyaluronic acid.

  16. Semi-Quantitative Method for Streptococci Magnetic Detection in Raw Milk

    Science.gov (United States)

    Duarte, Carla; Costa, Tiago; Carneiro, Carla; Soares, Rita; Jitariu, Andrei; Cardoso, Susana; Piedade, Moisés; Bexiga, Ricardo; Freitas, Paulo

    2016-01-01

    Bovine mastitis is the most costly disease for dairy farmers and the most frequent reason for the use of antibiotics in dairy cattle; thus, control measures to detect and prevent mastitis are crucial for dairy farm sustainability. The aim of this study was to develop and validate a sensitive method to magnetically detect Streptococcus agalactiae (a Group B streptococci) and Streptococcus uberis in raw milk samples. Mastitic milk samples were collected aseptically from 44 cows with subclinical mastitis, from 11 Portuguese dairy farms. Forty-six quarter milk samples were selected based on bacterial identification by conventional microbiology. All samples were submitted to PCR analysis. In parallel, these milk samples were mixed with a solution combining specific antibodies and magnetic nanoparticles, to be analyzed using a lab-on-a-chip magnetoresistive cytometer, with microfluidic sample handling. This paper describes a point of care methodology used for detection of bacteria, including analysis of false positive/negative results. This immunological recognition was able to detect bacterial presence in samples spiked above 100 cfu/mL, independently of antibody and targeted bacteria used in this work. Using PCR as a reference, this method correctly identified 73% of positive samples for streptococci species with an anti-S. agalactiae antibody, and 41% of positive samples for an anti-GB streptococci antibody. PMID:27128950

  17. Semi-Quantitative Method for Streptococci Magnetic Detection in Raw Milk

    Directory of Open Access Journals (Sweden)

    Carla Duarte

    2016-04-01

    Full Text Available Bovine mastitis is the most costly disease for dairy farmers and the most frequent reason for the use of antibiotics in dairy cattle; thus, control measures to detect and prevent mastitis are crucial for dairy farm sustainability. The aim of this study was to develop and validate a sensitive method to magnetically detect Streptococcus agalactiae (a Group B streptococci and Streptococcus uberis in raw milk samples. Mastitic milk samples were collected aseptically from 44 cows with subclinical mastitis, from 11 Portuguese dairy farms. Forty-six quarter milk samples were selected based on bacterial identification by conventional microbiology. All samples were submitted to PCR analysis. In parallel, these milk samples were mixed with a solution combining specific antibodies and magnetic nanoparticles, to be analyzed using a lab-on-a-chip magnetoresistive cytometer, with microfluidic sample handling. This paper describes a point of care methodology used for detection of bacteria, including analysis of false positive/negative results. This immunological recognition was able to detect bacterial presence in samples spiked above 100 cfu/mL, independently of antibody and targeted bacteria used in this work. Using PCR as a reference, this method correctly identified 73% of positive samples for streptococci species with an anti-S. agalactiae antibody, and 41% of positive samples for an anti-GB streptococci antibody.

  18. Facial Phenotyping by Quantitative Photography Reflects Craniofacial Morphology Measured on Magnetic Resonance Imaging in Icelandic Sleep Apnea Patients

    Science.gov (United States)

    Sutherland, Kate; Schwab, Richard J.; Maislin, Greg; Lee, Richard W.W.; Benedikstdsottir, Bryndis; Pack, Allan I.; Gislason, Thorarinn; Juliusson, Sigurdur; Cistulli, Peter A.

    2014-01-01

    Study Objectives: (1) To determine whether facial phenotype, measured by quantitative photography, relates to underlying craniofacial obstructive sleep apnea (OSA) risk factors, measured with magnetic resonance imaging (MRI); (2) To assess whether these associations are independent of body size and obesity. Design: Cross-sectional cohort. Setting: Landspitali, The National University Hospital, Iceland. Participants: One hundred forty patients (87.1% male) from the Icelandic Sleep Apnea Cohort who had both calibrated frontal and profile craniofacial photographs and upper airway MRI. Mean ± standard deviation age 56.1 ± 10.4 y, body mass index 33.5 ± 5.05 kg/m2, with on-average severe OSA (apnea-hypopnea index 45.4 ± 19.7 h-1). Interventions: N/A. Measurements and Results: Relationships between surface facial dimensions (photos) and facial bony dimensions and upper airway soft-tissue volumes (MRI) was assessed using canonical correlation analysis. Photo and MRI craniofacial datasets related in four significant canonical correlations, primarily driven by measurements of (1) maxillary-mandibular relationship (r = 0.8, P photography and MRI. This study confirms that facial photographic phenotype reflects underlying aspects of craniofacial skeletal abnormalities associated with OSA. Therefore, facial photographic phenotyping may be a useful tool to assess intermediate phenotypes for OSA, particularly in large-scale studies. Citation: Sutherland K, Schwab RJ, Maislin G, Lee RW, Benedikstdsottir B, Pack AI, Gislason T, Juliusson S, Cistulli PA. Facial phenotyping by quantitative photography reflects craniofacial morphology measured on magnetic resonance imaging in icelandic sleep apnea patients. SLEEP 2014;37(5):959-968. PMID:24790275

  19. Design, fabrication, and characterization of a solenoid system to generate magnetic field for an ECR proton source

    Indian Academy of Sciences (India)

    S K Jain; P A Naik; P R Hannurkar

    2010-08-01

    Solenoid coils with iron jacket (electromagnets) have been designed and developed for generation and confinement of the plasma produced by an electron cyclotron resonance source operating at 2450 MHz frequency. The magnetic field configurations designed using the solenoid coils are off-resonance, mirror, and flat, satisfying electron cyclotron resonance condition along the axis of the plasma chamber. 2D Poisson software was used for designing. Details of design, fabrication, and magnetic field mapping of the solenoid coils are presented in this paper.

  20. Cerebellar Volume and Proton Magnetic Resonance Spectroscopy at Term, and Neurodevelopment at 2 Years of Age in Preterm Infants

    Science.gov (United States)

    van Kooij, Britt J. M.; Benders, Manon J. N. L.; Anbeek, Petronella; van Haastert, Ingrid C.; de Vries, Linda S.; Groenendaal, Floris

    2012-01-01

    Aim: To assess the relation between cerebellar volume and spectroscopy at term equivalent age, and neurodevelopment at 24 months corrected age in preterm infants. Methods: Magnetic resonance imaging of the brain was performed around term equivalent age in 112 preterm infants (mean gestational age 28wks 3d [SD 1wk 5d]; birthweight 1129g [SD 324g]).…

  1. Cerebellar Volume and Proton Magnetic Resonance Spectroscopy at Term, and Neurodevelopment at 2 Years of Age in Preterm Infants

    Science.gov (United States)

    van Kooij, Britt J. M.; Benders, Manon J. N. L.; Anbeek, Petronella; van Haastert, Ingrid C.; de Vries, Linda S.; Groenendaal, Floris

    2012-01-01

    Aim: To assess the relation between cerebellar volume and spectroscopy at term equivalent age, and neurodevelopment at 24 months corrected age in preterm infants. Methods: Magnetic resonance imaging of the brain was performed around term equivalent age in 112 preterm infants (mean gestational age 28wks 3d [SD 1wk 5d]; birthweight 1129g [SD 324g]).…

  2. Cerebrovascular reactivity by quantitative magnetic resonance angiography with a co{sub 2} challenge. Validation as a new imaging biomarker

    Energy Technology Data Exchange (ETDEWEB)

    Caputi, Luigi, E-mail: lcaputi@istituto-besta.it [Department of Cerebrovascular Diseases, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan (Italy); Ghielmetti, Francesco, E-mail: Francesco.Ghielmetti@istituto-besta.it [Department of Neuroradiology, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan (Italy); Faragò, Giuseppe, E-mail: Giuseppe.Farago@istituto-besta.it [Department of Neuroradiology, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan (Italy); Longaretti, Fabio, E-mail: fabio.longaretti@libero.it [Department of Neuroradiology, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan (Italy); Lamperti, Massimo, E-mail: docmassimomd@gmail.com [Department of Neuroanesthesia and Intensive Care, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan (Italy); Anzola, Gian Paolo, E-mail: gpanzola@speedyposta.it [Service of Neurology, S. Orsola Hospital, Fondazione Poliambulanza, Via Vittorio Emanuele II 27, 25122 Brescia (Italy); Carriero, Maria Rita, E-mail: MariaRita.Carriero@istituto-besta.it [Department of Cerebrovascular Diseases, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan (Italy); Charbel, Fady T., E-mail: fcharbel@uic.edu [Department of Neurosurgery, University of Illinois at Chicago College of Medicine, Chicago, IL 60612 (United States); Bruzzone, Maria Grazia, E-mail: Maria.Bruzzone@istituto-besta.it [Department of Neuroradiology, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan (Italy); Parati, Eugenio, E-mail: Eugenio.Parati@istituto-besta.it [Department of Cerebrovascular Diseases, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan (Italy); Ciceri, Elisa, E-mail: Elisa.Ciceri@istituto-besta.it [Department of Neuroradiology, Fondazione IRCCS Neurological Institute C. Besta, Via Celoria 11, 20133 Milan (Italy)

    2014-06-15

    Assessment of cerebrovascular reactivity (CVR) is essential in cerebrovascular diseases, as exhausted CVR may enhance the risk of cerebral ischemic events. Transcranial Doppler (TCD) with a vasodilatory stimulus is currently used for CVR evaluation. Scanty data are available for Quantitative Magnetic Resonance Angiography (QMRA), which supplies higher spatial resolution and quantitative cerebral blood flow values. Aims of our pilot study were: (a) to assess safety and feasibility of CO{sub 2} administration during QMRA, (b) evaluation of CVR under QMRA compared to TCD, and (c) quantitative evaluation of blood flow from the major intracranial arterial vessels both at rest and after CO{sub 2}. CVR during 5% CO{sub 2} air breathing was measured with TCD as a reference method and compared with QMRA. Fifteen healthy subjects (age 60.47 ± 2.24; male 11/15) were evaluated at rest and during CO{sub 2} challenge. Feasibility and safety of QMRA under CO{sub 2} were ensured in all subjects. CVR from middle cerebral artery territory was not statistically different between TCD and MRI (p > 0.05). Mean arterial pressure (MAP) and heart rate (HR) increased during QMRA and TCD (MAP p = 0.007 and p = 0.001; HR p = 0.043 and p = 0.068, respectively). Blood flow values from all intracranial vessels increased after CO{sub 2} inhalation (p < 0.001). CO{sub 2} administration during QMRA sessions is safe and feasible. Good correlation in terms of CVR was obtained comparing TCD and QMRA. Blood flow values significantly increased from all intracranial arterial vessels after CO{sub 2}. Studies regarding CVR in physiopathological conditions might consider the utilization of QMRA both in routine clinical settings and in research projects.

  3. Topological phases of silicene and germanene in an external magnetic field: Quantitative results

    KAUST Repository

    Singh, Nirpendra

    2014-03-17

    We investigate the topological phases of silicene and germanene that arise due to the strong spin-orbit interaction in an external perpendicular magnetic field. Below and above a critical field of 10 T, respectively, we demonstrate for silicene under 3% tensile strain quantum spin Hall and quantum anomalous Hall phases. Not far above the critical field, and therefore in the experimentally accessible regime, we obtain an energy gap in the meV range, which shows that the quantum anomalous Hall phase can be realized experimentally in silicene, in contrast to graphene (tiny energy gap) and germanene (enormous field required). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Quantitative characterization and identification of lymph nodes and nasopharingeal carcinoma by coregistered magnetic resonance images.

    Science.gov (United States)

    Veronese, Fabio; Montin, Eros; Potepan, Paolo; Mainardi, Luca T

    2012-01-01

    In this study we developed a technique to improve the identification of carcinoma and pathological lymph nodes in cases of Nasopharingeal Carcinoma (NPC), through a quantitative characterization of the tissues based on MR images: 3D VIBE (Volumetric Interpolated Breath-hold Examination) T1-CE (Contrast Enhanced), T1, T2 and Diffusion Weighted Imaging (DWI) for b-values 0,300,500,700,1000. The procedure included two phases: 1) coregistration of volumes and 2) tissue characterization. Concerning the first phase, the DICOM images were reassembled spatially and resampled with isotropic 0.5mm resolution. Coregistration was performed by two multiresolution rigid transformations, merging head and neck volumes, plus a final multiresolution non rigid transformation. The anatomical 3D CE-VIBE volume was taken as reference. The procedure for tissue characterization is semi automated and it required a radiologist to identify an example of tissue from the primary tumor and a metastatic lymph node. We generated a 8-dimensional membership function to perform a fuzzy-like identification of these tissues. The result of this procedure was the generation of two maps, which showed complementary characterization of lymph nodes and carcinoma. A few example will be shown to evidence the potentiality of this method in identification and characterization of NPC lesions.

  5. Quantitative transmission electron microscopy analysis of the nanocrystallization kinetics of soft magnetic alloys

    Science.gov (United States)

    Ramanujan, R. V.; Zhang, Y. R.

    2006-12-01

    Transmission electron microscopy was used for the first time to obtain quantitative values of the diffusional crystallization kinetics of initially amorphous Fe74.5Si13.5B9Nb3 , Fe76.5Si13.5B9Cu1 and Fe73.5Si13.5B9Nb3Cu1 and Fe77.5Si13.5Nb3Cu1 (Finemet) alloys. The role of Cu and Nb alloying additions was elucidated. Contrary to some models of the crystallization process, it is demonstrated that both Nb and Cu alloying additions can influence the nucleation and growth processes. Combined additions of both Cu and Nb induce drastic reduction in crystal size to about 10nm and 1000 times higher crystal number density. The high nucleation rate observed in the Fe-Si-B-Nb-Cu alloy was attributed to the formation of both Cu and Nb rich regions which provide a high number of heterogeneous nucleation sites, consistent with the Hampel and Pradell models, the low growth rate was consistent with the Hunziker model.

  6. Two-dimensional Hybrid Simulations of Kinetic Plasma Turbulence: Current and Vorticity vs Proton Temperature

    CERN Document Server

    Franci, Luca; Matteini, Lorenzo; Verdini, Andrea; Landi, Simone

    2016-01-01

    Proton temperature anisotropies between the directions parallel and perpendicular to the mean magnetic field are usually observed in the solar wind plasma. Here, we employ a high-resolution hybrid particle-in-cell simulation in order to investigate the relation between spatial properties of the proton temperature and the peaks in the current density and in the flow vorticity. Our results indicate that, although regions where the proton temperature is enhanced and temperature anisotropies are larger correspond approximately to regions where many thin current sheets form, no firm quantitative evidence supports the idea of a direct causality between the two phenomena. On the other hand, quite a clear correlation between the behavior of the proton temperature and the out-of-plane vorticity is obtained.

  7. Translational Approaches for Studying Neurodevelopmental Disorders Utilizing in Vivo Proton (+H) Magnetic Resonance Spectroscopic Imaging in Rats

    Science.gov (United States)

    Ronca, April E.

    2014-01-01

    Intrauterine complications have been implicated in the etiology of neuripsychiatric disorders including schizophrenia, autism and ADHD. This presentation will describe new translational studies derived from in vivo magnetic resonance imaging of developing and adult brain following perinatal asphyxia (PA). Our findings reveal significant effects of PA on neurometabolic profiles at one week of age, and significant relationships between early metabolites and later life phenotypes including behavior and brain morphometry

  8. The new dc power supply system for the main ring magnets of the 28 GeV CERN proton synchrotron

    CERN Document Server

    Jahn, K; Steckmann, E

    1972-01-01

    High overload capacity, low residual ripple, exact reproducibility of periodic current pulses and very great reliability in long-term duty are essential requirements for a modern power supply system for feeding beam-guide magnets. These requirements can be met with certainty and at reasonable cost by the use of high-performance single-anode mercury-arc converters with suitable electronic control and protective equipment. (4 refs).

  9. Cardiac dysfunction in the diabetic rat: quantitative evaluation using high resolution magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Alenezy Mohammed D

    2006-04-01

    Full Text Available Abstract Background Diabetes is a major risk factor for cardiovascular disease. In particular, type 1 diabetes compromises the cardiac function of individuals at a relatively early age due to the protracted course of abnormal glucose homeostasis. The functional abnormalities of diabetic myocardium have been attributed to the pathological changes of diabetic cardiomyopathy. Methods In this study, we used high field magnetic resonance imaging (MRI to evaluate the left ventricular functional characteristics of streptozotocin treated diabetic Sprague-Dawley rats (8 weeks disease duration in comparison with age/sex matched controls. Results Our analyses of EKG gated cardiac MRI scans of the left ventricle showed a 28% decrease in the end-diastolic volume and 10% increase in the end-systolic volume of diabetic hearts compared to controls. Mean stroke volume and ejection fraction in diabetic rats were decreased (48% and 28%, respectively compared to controls. Further, dV/dt changes were suggestive of phase sensitive differences in left ventricular kinetics across the cardiac cycle between diabetic and control rats. Conclusion Thus, the MRI analyses of diabetic left ventricle suggest impairment of diastolic and systolic hemodynamics in this rat model of diabetic cardiomyopathy. Our studies also show that in vivo MRI could be used in the evaluation of cardiac dysfunction in this rat model of type 1 diabetes.

  10. Quantitation of mitral regurgitation with cardiac magnetic resonance imaging: a systematic review.

    Science.gov (United States)

    Krieger, Eric V; Lee, James; Branch, Kelley R; Hamilton-Craig, Christian

    2016-12-01

    In this review discuss the application of cardiac magnetic resonance (CMR) to the evaluation and quantification of mitral regurgitation and provide a systematic literature review for comparisons with echocardiography. Using the 2015 Preferred Reporting Items for Systematic Reviews and Meta-Analyses methodology, we searched Medline and PubMed for original research articles published since 2000 that provided data on the quantification of mitral regurgitation by CMR. We identified 220 articles of which 33 were included. Four main techniques of mitral regurgitation quantification were identified. Reproducibility varied substantially between papers but was high overall for all techniques. However, quantification differed between the techniques studied. When compared with two-dimensional echocardiography, mitral regurgitation fraction and regurgitant volume measured by CMR were comparable but typically lower. CMR has high reproducibility for the quantification of mitral regurgitation in experienced centres, but further technological refinement is needed. An integrated and standardised approach that combines multiple techniques is recommended for optimal reproducibility and precise mitral regurgitation quantification. Definitive outcome studies using CMR as a basis for treatment are lacking but needed.

  11. Quantitative magnetic resonance imaging volumetry distinguishes delusional disorder from late-onset schizophrenia.

    Science.gov (United States)

    Howard, R J; Almeida, O; Levy, R; Graves, P; Graves, M

    1994-10-01

    Late paraphrenia is recognised as a heterogeneous disorder. This is reflected by the division of such patients into schizophrenia and delusional disorder in ICD-10. Earlier imaging studies have suggested that major structural abnormalities may be associated with the onset of psychosis in later life. Fifty late paraphrenics and 35 age-matched healthy controls underwent structural magnetic resonance imaging of the whole brain in the coronal plane. Measurements were made of intracranial and brain volumes and the volumes of the intracerebral and extracerebral cerebrospinal fluid spaces. No differences in intracranial, brain or extracerebral cerebrospinal fluid volumes between patients and controls were found. Late paraphrenic patients had greater lateral and third ventricle volumes than controls and the left lateral ventricle was larger than the right. When the patients were divided into appropriate ICD-10 diagnoses: paranoid schizophrenia (n = 31) and delusional disorder (n = 16), lateral ventricle volumes in the delusional disorder patients were much greater than those of the schizophrenics and almost twice those of controls. Structural brain differences underly diagnostic heterogeneity within late paraphrenia. The brains of late onset schizophrenics are only subtly different from those of healthy elderly individuals.

  12. Magnetic shear in flaring regions. I - Quantitative evaluation of the change in shear

    Science.gov (United States)

    Sivaraman, K. R.; Rausaria, R. R.; Aleem, S. M.

    1992-04-01

    The shear angle of the neutral line of the nonpotential magnetic field has been evaluated for one or two days prior to and after the flare event for 10 cases. The H-alpha filament positions were used to evaluate the shear in the neutral line. It is found that it is the change in the shear that occurs a day prior to the flare that can lead to the event. This change can be in either direction, i.e., it can be a large increase from a small value or a decrease from a large initial value. Thus it is the change in the shear angle that seems to be a deciding criterion for a flare to occur and not a large value for the shear angle itself. One instance is found where there was no significant change in the shear angle over a period of a few days and this region, although similar to other active regions studied, did not produce any flare activity.

  13. Sensor fusion of electron paramagnetic resonance and magnetorelaxometry data for quantitative magnetic nanoparticle imaging

    Science.gov (United States)

    Coene, A.; Leliaert, J.; Crevecoeur, G.; Dupré, L.

    2017-03-01

    Magnetorelaxometry (MRX) imaging and electron paramagnetic resonance (EPR) are two non-invasive techniques capable of recovering the magnetic nanoparticle (MNP) distribution. Both techniques solve an ill-posed inverse problem in order to find the spatial MNP distribution. A lot of research has been done on increasing the stability of these inverse problems with the main objective to improve the quality of MNP imaging. In this paper a proof of concept is presented in which the sensor data of both techniques is fused into EPR–MRX, with the intention to stabilize the inverse problem. First, both techniques are compared by reconstructing several phantoms with different sizes for various noise levels and calculating stability, sensitivity and reconstruction quality parameters for these cases. This study reveals that both techniques are sensitive to different information from the MNP distributions and generate complementary measurement data. As such, their merging might stabilize the inverse problem. In a next step we investigated how both techniques need to be combined to reduce their respective drawbacks, such as a high number of required measurements and reduced stability, and to improve MNP reconstructions. We were able to stabilize both techniques, increase reconstruction quality by an average of 5% and reduce measurement times by 88%. These improvements could make EPR–MRX a valuable and accurate technique in a clinical environment.

  14. Quantitative myocardial perfusion magnetic resonance imaging: the impact of pulsatile flow on contrast agent bolus dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Graafen, Dirk; Hamer, Julia; Weber, Stefan; Schreiber, Laura M, E-mail: graafen@uni-mainz.de [Section of Medical Physics, Department of Radiology, Johannes Gutenberg University Medical Center, Mainz (Germany)

    2011-08-21

    Myocardial blood flow (MBF) can be quantified using T{sub 1}-weighted first-pass magnetic resonance imaging (MRI) in combination with a tracer-kinetic model, like MMID4. This procedure requires the knowledge of an arterial input function which is usually estimated from the left ventricle (LV). Dispersion of the contrast agent bolus may occur between the LV and the tissue of interest. The aim of this study was to investigate the dispersion under conditions of physiological pulsatile blood flow, and to simulate its effect on MBF quantification. The dispersion was simulated in coronary arteries using a computational fluid dynamics (CFD) approach. Simulations were accomplished on straight vessels with stenosis of different degrees and shapes. The results show that dispersion is more pronounced under resting conditions than during hyperemia. Stenosis leads to a reduction of dispersion. In consequence, dispersion results in a systematic MBF underestimation between -0.4% and -9.3%. The relative MBF error depends not only on the dispersion but also on the actual MBF itself. Since MBF under rest is more underestimated than under stress, myocardial perfusion reserve is overestimated between 0.1% and 4.5%. Considering other sources of errors in myocardial perfusion MRI, systematic errors of MBF by bolus dispersion are relatively small.

  15. Proton Therapy

    Science.gov (United States)

    Oelfke, Uwe

    Proton therapy is one of the most rapidly developing new treatment technologies in radiation oncology. This treatment approach has — after roughly 40 years of technical developments — reached a mature state that allows a widespread clinical application. We therefore review the basic physical and radio-biological properties of proton beams. The main physical aspect is the elemental dose distribution arising from an infinitely narrow proton pencil beam. This includes the physics of proton stopping powers and the concept of CSDA range. Furthermore, the process of multiple Coulomb scattering is discussed for the lateral dose distribution. Next, the basic terms for the description of radio-biological properties of proton beams like LET and RBE are briefly introduced. Finally, the main concepts of modern proton dose delivery concepts are introduced before the standard method of inverse treatment planning for hadron therapy is presented.

  16. Absolute quantitative proton NMR spectroscopy based on the amplitude of the local water suppression pulse. Quantification of brain water and metabolites

    DEFF Research Database (Denmark)

    Danielsen, E R; Henriksen, O

    1994-01-01

    Quantification in localized proton NMR spectroscopy has been achieved by various methods in recent years. A new method for absolute quantification is described in this paper. The method simultaneously rules out problems with B1 field inhomogeneity and coil loading, utilizing a relation between...... the locally optimized amplitude of a chemical shift selective water suppression pulse and the acquired signal. Validity and feasibility of quantification using the method of the water suppression pulse is demonstrated. Brain water and cerebral metabolites have been quantified in a study of 12 healthy...

  17. Changes to Intermediary Metabolites in Sporadic and LRRK2 Parkinson’s Disease Demonstrated by Proton Magnetic Resonance Spectroscopy

    Directory of Open Access Journals (Sweden)

    Jan O. Aasly

    2015-01-01

    Full Text Available Background. Parkinson’s disease (PD remains a clinical diagnosis and biomarkers are needed to detect the disease as early as possible. Genetically determined PD provides an opportunity for studying metabolic differences in connection with disease development. Objectives. To study the levels of intermediary metabolites in cerebrospinal fluid (CSF from patients with PD, either of sporadic type or in carriers of the LRRK2 p.G2019S mutation. Methods. Results from patients with sporadic PD or LRRK2-PD were compared with asymptomatic LRRK2 mutation carriers and healthy control individuals. CSF was analysed by proton MR spectroscopy (1H-MRS giving reliable results for 16 intermediary metabolites. Partial least squares discriminant analysis (PLS-DA was applied to study group differences. Results. PLS-DA distinguished PD patients from healthy individuals based on the metabolites identified in CSF, with 2-hydroxybutyrate, glutamine, and dimethyl sulphone largely contributing to the separations. Conclusion. Speculatively, all three metabolites could alter concentration in response to metabolic changes connected with neurodegeneration; glutamine as a means of removing excess nitrogen from brain, dimethyl sulphone as an anti-inflammatory agent, and 2-hydroxybutyrate in connection with altered glutathione metabolism. Potentially, 1H-MRS is a promising tool for identifying novel biomarkers for PD.

  18. In vivo measurement of regional brain metabolic response to hyperventilation using magnetic resonance: proton echo planar spectroscopic imaging (PEPSI).

    Science.gov (United States)

    Posse, S; Dager, S R; Richards, T L; Yuan, C; Ogg, R; Artru, A A; Müller-Gärtner, H W; Hayes, C

    1997-06-01

    A new rapid spectroscopic imaging technique with improved sensitivity and lipid suppression, referred to as Proton Echo Planar Spectroscopic Imaging (PEPSI), has been developed to measure the 2-dimensional distribution of brain lactate increases during hyperventilation on a conventional clinical scanner equipped with a head surface coil phased array. PEPSI images (nominal voxel size: 1.125 cm3) in five healthy subjects from an axial section approximately 20 mm inferior to the intercommissural line were obtained during an 8.5-min baseline period of normocapnia and during the final 8.5 min of a 10-min period of capnometry-controlled hyperventilation (end-tidal PCO2 of 20 mmHg). The lactate/N-acetyl aspartate signal increased significantly from baseline during hyperventilation for the insular cortex, temporal cortex, and occipital regions of both the right and left hemisphere, but not in the basal ganglia. Regional or hemispheric right-to-left differences were not found. The study extends previous work using single-voxel MR spectroscopy to dynamically study hyperventilation effects on brain metabolism.

  19. Combination of high-resolution magic angle spinning proton magnetic resonance spectroscopy and microscale genomics to type brain tumor biopsies.

    Science.gov (United States)

    Tzika, A Aria; Astrakas, Loukas; Cao, Haihui; Mintzopoulos, Dionyssios; Andronesi, Ovidiu C; Mindrinos, Michael; Zhang, Jiangwen; Rahme, Laurence G; Blekas, Konstantinos D; Likas, Aristidis C; Galatsanos, Nikolas P; Carroll, Rona S; Black, Peter M

    2007-08-01

    Advancements in the diagnosis and prognosis of brain tumor patients, and thus in their survival and quality of life, can be achieved using biomarkers that facilitate improved tumor typing. We introduce and implement a combinatorial metabolic and molecular approach that applies state-of-the-art, high-resolution magic angle spinning (HRMAS) proton (1H) MRS and gene transcriptome profiling to intact brain tumor biopsies, to identify unique biomarker profiles of brain tumors. Our results show that samples as small as 2 mg can be successfully processed, the HRMAS 1H MRS procedure does not result in mRNA degradation, and minute mRNA amounts yield high-quality genomic data. The MRS and genomic analyses demonstrate that CNS tumors have altered levels of specific 1H MRS metabolites that directly correspond to altered expression of Kennedy pathway genes; and exhibit rapid phospholipid turnover, which coincides with upregulation of cell proliferation genes. The data also suggest Sonic Hedgehog pathway (SHH) dysregulation may play a role in anaplastic ganglioglioma pathogenesis. That a strong correlation is seen between the HRMAS 1H MRS and genomic data cross-validates and further demonstrates the biological relevance of the MRS results. Our combined metabolic/molecular MRS/genomic approach provides insights into the biology of anaplastic ganglioglioma and a new potential tumor typing methodology that could aid neurologists and neurosurgeons to improve the diagnosis, treatment, and ongoing evaluation of brain tumor patients.

  20. Quantitative evaluation of susceptibility effects caused by dental materials in head magnetic resonance imaging

    Science.gov (United States)

    Strocchi, S.; Ghielmi, M.; Basilico, F.; Macchi, A.; Novario, R.; Ferretti, R.; Binaghi, E.

    2016-03-01

    This work quantitatively evaluates the effects induced by susceptibility characteristics of materials commonly used in dental practice on the quality of head MR images in a clinical 1.5T device. The proposed evaluation procedure measures the image artifacts induced by susceptibility in MR images by providing an index consistent with the global degradation as perceived by the experts. Susceptibility artifacts were evaluated in a near-clinical setup, using a phantom with susceptibility and geometric characteristics similar to that of a human head. We tested different dentist materials, called PAL Keramit, Ti6Al4V-ELI, Keramit NP, ILOR F, Zirconia and used different clinical MR acquisition sequences, such as "classical" SE and fast, gradient, and diffusion sequences. The evaluation is designed as a matching process between reference and artifacts affected images recording the same scene. The extent of the degradation induced by susceptibility is then measured in terms of similarity with the corresponding reference image. The matching process involves a multimodal registration task and the use an adequate similarity index psychophysically validated, based on correlation coefficient. The proposed analyses are integrated within a computer-supported procedure that interactively guides the users in the different phases of the evaluation method. 2-Dimensional and 3-dimensional indexes are used for each material and each acquisition sequence. From these, we drew a ranking of the materials, averaging the results obtained. Zirconia and ILOR F appear to be the best choice from the susceptibility artefacts point of view, followed, in order, by PAL Keramit, Ti6Al4V-ELI and Keramit NP.

  1. Semi-quantitative assessment of right ventricular function in comparison to a 3D volumetric approach: A cardiovascular magnetic resonance study

    NARCIS (Netherlands)

    Nijveldt, Robin; Germans, Tjeerd; McCann, Gerald; Beek, Aernout; Rossum, van Albert

    2008-01-01

    Right ventricular (RV) volume measurements with cardiovascular magnetic resonance (CMR) is considered the gold standard, but acquisition and analysis remain timeconsuming. The aim of our study was therefore to investigate the accuracy and performance of a semi-quantitative assessment of RV function

  2. Semi-quantitative assessment of right ventricular function in comparison to a 3D volumetric approach: A cardiovascular magnetic resonance study

    NARCIS (Netherlands)

    Nijveldt, Robin; Germans, Tjeerd; McCann, Gerald; Beek, Aernout; Rossum, van Albert

    2008-01-01

    Right ventricular (RV) volume measurements with cardiovascular magnetic resonance (CMR) is considered the gold standard, but acquisition and analysis remain timeconsuming. The aim of our study was therefore to investigate the accuracy and performance of a semi-quantitative assessment of RV function

  3. Left ventricular modelling: a quantitative functional assessment tool based on cardiac magnetic resonance imaging

    Science.gov (United States)

    Conti, C. A.; Votta, E.; Corsi, C.; De Marchi, D.; Tarroni, G.; Stevanella, M.; Lombardi, M.; Parodi, O.; Caiani, E. G.; Redaelli, A.

    2011-01-01

    We present the development and testing of a semi-automated tool to support the diagnosis of left ventricle (LV) dysfunctions from cardiac magnetic resonance (CMR). CMR short-axis images of the LVs were obtained in 15 patients and processed to detect endocardial and epicardial contours and compute volume, mass and regional wall motion (WM). Results were compared with those obtained from manual tracing by an expert cardiologist. Nearest neighbour tracking and finite-element theory were merged to calculate local myocardial strains and torsion. The method was tested on a virtual phantom, on a healthy LV and on two ischaemic LVs with different severity of the pathology. Automated analysis of CMR data was feasible in 13/15 patients: computed LV volumes and wall mass correlated well with manually extracted data. The detection of regional WM abnormalities showed good sensitivity (77.8%), specificity (85.1%) and accuracy (82%). On the virtual phantom, computed local strains differed by less than 14 per cent from the results of commercial finite-element solver. Strain calculation on the healthy LV showed uniform and synchronized circumferential strains, with peak shortening of about 20 per cent at end systole, progressively higher systolic wall thickening going from base to apex, and a 10° torsion. In the two pathological LVs, synchronicity and homogeneity were partially lost, anomalies being more evident for the more severely injured LV. Moreover, LV torsion was dramatically reduced. Preliminary testing confirmed the validity of our approach, which allowed for the fast analysis of LV function, even though future improvements are possible. PMID:22670208

  4. The cavernous sinus in cluster headache - a quantitative structural magnetic resonance imaging study.

    Science.gov (United States)

    Arkink, Enrico B; Schoonman, Guus G; van Vliet, Jorine A; Bakels, Hannah S; Sneeboer, Marjolein Am; Haan, Joost; van Buchem, Mark A; Ferrari, Michel D; Kruit, Mark C

    2017-03-01

    Background It has been hypothesized that a constitutionally narrow cavernous sinus might predispose individuals to cluster headache. Cavernous sinus dimensions, however, have never been assessed. Methods In this case-control study, we measured the dimensions of the cavernous sinus, skull base, internal carotid and pituitary gland with high-resolution T2-weighted magnetic resonance imaging in 25 episodic, 24 chronic and 13 probable cluster headache patients, 8 chronic paroxysmal hemicrania patients and 22 headache-free controls. Dimensions were compared between groups, correcting for age, sex and transcranial diameter. Results On qualitative inspection, no relevant pathology or anatomic variants that were previously associated with cluster headache or chronic paroxysmal hemicranias were observed in the cavernous sinus or paracavernous structures. The left-to-right transcranial diameter at the temporal fossa level (mean ± SD) was larger in the headache groups (episodic cluster headache: 147.5 ± 7.3 mm, p = 0.044; chronic cluster headache: 150.2 ± 7.3 mm, p cluster headache: 146.0 ± 5.3 mm, p = 0.012; and chronic paroxysmal hemicrania: 145.2 ± 9.4 mm, p = 0.044) compared with controls (140.2 ± 8.0 mm). After adjusting for transcranial diameter and correcting for multiple comparisons, there were no differences in the dimensions of the cavernous sinus and surrounding structures between headache patients and controls. Conclusion Patients with cluster headache or chronic paroxysmal hemicrania had wider skulls than headache-free controls, but the proportional dimensions of the cavernous sinus were similar.

  5. Proton therapy in the clinic.

    Science.gov (United States)

    DeLaney, Thomas F

    2011-01-01

    The clinical advantage for proton radiotherapy over photon approaches is the marked reduction in integral dose to the patient, due to the absence of exit dose beyond the proton Bragg peak. The integral dose with protons is approximately 60% lower than that with any external beam photon technique. Pediatric patients, because of their developing normal tissues and anticipated length of remaining life, are likely to have the maximum clinical gain with the use of protons. Proton therapy may also allow treatment of some adult tumors to much more effective doses, because of normal tissue sparing distal to the tumor. Currently, the most commonly available proton treatment technology uses 3D conformal approaches based on (a) distal range modulation, (b) passive scattering of the proton beam in its x- and y-axes, and (c) lateral beam-shaping. It is anticipated that magnetic pencil beam scanning will become the dominant mode of proton delivery in the future, which will lower neutron scatter associated with passively scattered beam lines, reduce the need for expensive beam-shaping devices, and allow intensity-modulated proton radiotherapy. Proton treatment plans are more sensitive to variations in tumor size and normal tissue changes over the course of treatment than photon plans, and it is expected that adaptive radiation therapy will be increasingly important for proton therapy as well. While impressive treatment results have been reported with protons, their cost is higher than for photon IMRT. Hence, protons should ideally be employed for anatomic sites and tumors not well treated with photons. While protons appear cost-effective for pediatric tumors, their cost-effectiveness for treatment of some adult tumors, such as prostate cancer, is uncertain. Comparative studies have been proposed or are in progress to more rigorously assess their value for a variety of sites. The utility of proton therapy will be enhanced by technological developments that reduce its cost

  6. Machine learning applied to proton radiography of high-energy-density plasmas

    Science.gov (United States)

    Chen, Nicholas F. Y.; Kasim, Muhammad Firmansyah; Ceurvorst, Luke; Ratan, Naren; Sadler, James; Levy, Matthew C.; Trines, Raoul; Bingham, Robert; Norreys, Peter

    2017-04-01

    Proton radiography is a technique extensively used to resolve magnetic field structures in high-energy-density plasmas, revealing a whole variety of interesting phenomena such as magnetic reconnection and collisionless shocks found in astrophysical systems. Existing methods of analyzing proton radiographs give mostly qualitative results or specific quantitative parameters, such as magnetic field strength, and recent work showed that the line-integrated transverse magnetic field can be reconstructed in specific regimes where many simplifying assumptions were needed. Using artificial neural networks, we demonstrate for the first time 3D reconstruction of magnetic fields in the nonlinear regime, an improvement over existing methods, which reconstruct only in 2D and in the linear regime. A proof of concept is presented here, with mean reconstruction errors of less than 5% even after introducing noise. We demonstrate that over the long term, this approach is more computationally efficient compared to other techniques. We also highlight the need for proton tomography because (i) certain field structures cannot be reconstructed from a single radiograph and (ii) errors can be further reduced when reconstruction is performed on radiographs generated by proton beams fired in different directions.

  7. Assessing agreement between preclinical magnetic resonance imaging and histology: An evaluation of their image qualities and quantitative results.

    Science.gov (United States)

    Elschner, Cindy; Korn, Paula; Hauptstock, Maria; Schulz, Matthias C; Range, Ursula; Jünger, Diana; Scheler, Ulrich

    2017-01-01

    One consequence of demographic change is the increasing demand for biocompatible materials for use in implants and prostheses. This is accompanied by a growing number of experimental animals because the interactions between new biomaterials and its host tissue have to be investigated. To evaluate novel materials and engineered tissues the use of non-destructive imaging modalities have been identified as a strategic priority. This provides the opportunity for studying interactions repeatedly with individual animals, along with the advantages of reduced biological variability and decreased number of laboratory animals. However, histological techniques are still the golden standard in preclinical biomaterial research. The present article demonstrates a detailed method comparison between histology and magnetic resonance imaging. This includes the presentation of their image qualities as well as the detailed statistical analysis for assessing agreement between quantitative measures. Exemplarily, the bony ingrowth of tissue engineered bone substitutes for treatment of a cleft-like maxillary bone defect has been evaluated. By using a graphical concordance analysis the mean difference between MRI results and histomorphometrical measures has been examined. The analysis revealed a slightly but significant bias in the case of the bone volume [Formula: see text] and a clearly significant deviation for the remaining defect width [Formula: see text] But the study although showed a considerable effect of the analyzed section position to the quantitative result. It could be proven, that the bias of the data sets was less originated due to the imaging modalities, but mainly on the evaluation of different slice positions. The article demonstrated that method comparisons not always need the use of an independent animal study, additionally.

  8. Deferasirox, deferiprone and desferrioxamine treatment in thalassemia major patients: cardiac iron and function comparison determined by quantitative magnetic resonance imaging

    Science.gov (United States)

    Pepe, Alessia; Meloni, Antonella; Capra, Marcello; Cianciulli, Paolo; Prossomariti, Luciano; Malaventura, Cristina; Putti, Maria Caterina; Lippi, Alma; Romeo, Maria Antonietta; Bisconte, Maria Grazia; Filosa, Aldo; Caruso, Vincenzo; Quarta, Antonella; Pitrolo, Lorella; Missere, Massimiliano; Midiri, Massimo; Rossi, Giuseppe; Positano, Vincenzo; Lombardi, Massimo; Maggio, Aurelio

    2011-01-01

    Background Oral deferiprone was suggested to be more effective than subcutaneous desferrioxamine for removing heart iron. Oral once-daily chelator deferasirox has recently been made commercially available but its long-term efficacy on cardiac iron and function has not yet been established. Our study aimed to compare the effectiveness of deferasirox, deferiprone and desferrioxamine on myocardial and liver iron concentrations and bi-ventricular function in thalassemia major patients by means of quantitative magnetic resonance imaging. Design and Methods From the first 550 thalassemia subjects enrolled in the Myocardial Iron Overload in Thalassemia network, we retrospectively selected thalassemia major patients who had been receiving one chelator alone for longer than one year. We identified three groups of patients: 24 treated with deferasirox, 42 treated with deferiprone and 89 treated with desferrioxamine. Myocardial iron concentrations were measured by T2* multislice multiecho technique. Biventricular function parameters were quantitatively evaluated by cine images. Liver iron concentrations were measured by T2* multiecho technique. Results The global heart T2* value was significantly higher in the deferiprone (34±11ms) than in the deferasirox (21±12 ms) and the desferrioxamine groups (27±11 ms) (P=0.0001). We found higher left ventricular ejection fractions in the deferiprone and the desferrioxamine versus the deferasirox group (P=0.010). Liver iron concentration, measured as T2* signal, was significantly lower in the desferrioxamine versus the deferiprone and the deferasirox group (P=0.004). Conclusions The cohort of patients treated with oral deferiprone showed less myocardial iron burden and better global systolic ventricular function compared to the patients treated with oral deferasirox or subcutaneous desferrioxamine. PMID:20884710

  9. Simultaneous Quantitative MRI Mapping of T1, T2* and Magnetic Susceptibility with Multi-Echo MP2RAGE

    Science.gov (United States)

    Kober, Tobias; Möller, Harald E.; Schäfer, Andreas

    2017-01-01

    The knowledge of relaxation times is essential for understanding the biophysical mechanisms underlying contrast in magnetic resonance imaging. Quantitative experiments, while offering major advantages in terms of reproducibility, may benefit from simultaneous acquisitions. In this work, we demonstrate the possibility of simultaneously recording relaxation-time and susceptibility maps with a prototype Multi-Echo (ME) Magnetization-Prepared 2 RApid Gradient Echoes (MP2RAGE) sequence. T1 maps can be obtained using the MP2RAGE sequence, which is relatively insensitive to inhomogeneities of the radio-frequency transmit field, B1+. As an extension, multiple gradient echoes can be acquired in each of the MP2RAGE readout blocks, which permits the calculation of T2* and susceptibility maps. We used computer simulations to explore the effects of the parameters on the precision and accuracy of the mapping. In vivo parameter maps up to 0.6 mm nominal resolution were acquired at 7 T in 19 healthy volunteers. Voxel-by-voxel correlations and the test-retest reproducibility were used to assess the reliability of the results. When using optimized paramenters, T1 maps obtained with ME-MP2RAGE and standard MP2RAGE showed excellent agreement for the whole range of values found in brain tissues. Simultaneously obtained T2* and susceptibility maps were of comparable quality as Fast Low-Angle SHot (FLASH) results. The acquisition times were more favorable for the ME-MP2RAGE (≈ 19 min) sequence as opposed to the sum of MP2RAGE (≈ 12 min) and FLASH (≈ 10 min) acquisitions. Without relevant sacrifice in accuracy, precision or flexibility, the multi-echo version may yield advantages in terms of reduced acquisition time and intrinsic co-registration, provided that an appropriate optimization of the acquisition parameters is performed. PMID:28081157

  10. Starch biosynthesis and intermediary metabolism in maize kernels. Quantitative analysis of metabolite flux by nuclear magnetic resonance.

    Science.gov (United States)

    Glawischnig, Erich; Gierl, Alfons; Tomas, Adriana; Bacher, Adelbert; Eisenreich, Wolfgang

    2002-12-01

    The seeds of cereals represent an important sink for metabolites during the accumulation of storage products, and seeds are an essential component of human and animal nutrition. Understanding the metabolic interconversions (networks) underpinning storage product formation could provide the foundation for effective metabolic engineering of these primary nutritional sources. In this paper, we describe the use of retrobiosynthetic nuclear magnetic resonance analysis to establish the metabolic history of the glucose (Glc) units of starch in maize (Zea mays) kernels. Maize kernel cultures were grown with [U-(13)C(6)]Glc, [U-(13)C(12)]sucrose, or [1,2-(13)C(2)]acetate as supplements. After 19 d, starch was hydrolyzed, and the isotopomer composition of the resulting Glc was determined by quantitative nuclear magnetic resonance analysis. [1,2-(13)C(2)]Acetate was not incorporated into starch. [U-(13)C(6)]Glc or [U-(13)C(12)]sucrose gave similar labeling patterns of polysaccharide Glc units, which were dominated by [1,2,3-(13)C(3)]- and [4,5,6-(13)C(3)]-isotopomers, whereas the [U-(13)C(6)]-, [3,4,5,6-(13)C(4)]-, [1,2-(13)C(2)]-, [5,6-(13)C(2)], [3-(13)C(1)], and [4-(13)C(1)]-isotopomers were present at lower levels. These isotopomer compositions indicate that there is extensive recycling of Glc before its incorporation into starch, via the enzymes of glycolytic, glucogenic, and pentose phosphate pathways. The relatively high abundance of the [5,6-(13)C(2)]-isotopomer can be explained by the joint operation of glycolysis/glucogenesis and the pentose phosphate pathway.

  11. In vivo proton magnetic resonance spectroscopy (1H-MRS) evaluation of the metabolite concentration of optic radiation in primary open angle glaucoma

    Energy Technology Data Exchange (ETDEWEB)

    Sidek, Sabrilhakim [University of Malaya, Department of Biomedical Imaging, University Malaya Research Imaging Centre (UMRIC), Kuala Lumpur (Malaysia); Universiti Teknologi MARA, Medical Imaging Unit, Faculty of Medicine, Sg Buloh, Selangor (Malaysia); Ramli, Norlisah; Rahmat, Kartini; Kuo, Tan Li [University of Malaya, Department of Biomedical Imaging, University Malaya Research Imaging Centre (UMRIC), Kuala Lumpur (Malaysia); Ramli, Norlina Mohd; Abdulrahman, Fadzlina [University of Malaya, Department of Ophthalmology, Faculty of Medicine, Kuala Lumpur (Malaysia)

    2016-12-15

    To compare the metabolite concentration of optic radiation in glaucoma patients with that of healthy subjects using Proton Magnetic Resonance Spectroscopy (1H-MRS). 1H-MRS utilising the Single-Voxel Spectroscopy (SVS) technique was performed using a 3.0Tesla MRI on 45 optic radiations (15 from healthy subjects, 15 from mild glaucoma patients, and 15 from severe glaucoma patients). A standardised Volume of Interest (VOI) of 20 x 20 x 20 mm was placed in the region of optic radiation. Mild and severe glaucoma patients were categorised based on the Hodapp-Parrish-Anderson (HPA) classification. Mean and multiple group comparisons for metabolite concentration and metabolite concentration ratio between glaucoma grades and healthy subjects were obtained using one-way ANOVA. The metabolite concentration and metabolite concentration ratio between the optic radiations of glaucoma patients and healthy subjects did not demonstrate any significant difference (p > 0.05). Our findings show no significant alteration of metabolite concentration associated with neurodegeneration that could be measured by single-voxel 1H-MRS in optic radiation among glaucoma patients. (orig.)

  12. Metabolic Changes in the Bilateral Visual Cortex of the Monocular Blind Macaque: A Multi-Voxel Proton Magnetic Resonance Spectroscopy Study.

    Science.gov (United States)

    Wu, Lingjie; Tang, Zuohua; Feng, Xiaoyuan; Sun, Xinghuai; Qian, Wen; Wang, Jie; Jin, Lixin; Jiang, Jingxuan; Zhong, Yufeng

    2017-02-01

    The metabolic changes accompanied with adaptive plasticity in the visual cortex after early monocular visual loss were unclear. In this study, we detected the metabolic changes in bilateral visual cortex of normal (group A) and monocular blind macaque (group B) for studying the adaptive plasticity using multi-voxel proton magnetic resonance spectroscopy ((1)H-MRS) at 32 months after right optic nerve transection. Then, we compared the N-Acetyl aspartate (NAA)/Creatine (Cr), myoinositol (Ins)/Cr, choline (Cho)/Cr and Glx (Glutamate + glutamine)/Cr ratios in the visual cortex between two groups, as well as between the left and right visual cortex of group A and B. Compared with group A, in the bilateral visual cortex, a decreased NAA/Cr and Glx/Cr ratios in group B were found, which was more clearly in the right visual cortex; whereas the Ins/Cr and Cho/Cr ratios of group B were increased. All of these findings were further confirmed by immunohistochemical staining. In conclusion, the difference of metabolic ratios can be detected by multi-voxel (1)H-MRS in the visual cortex between groups A and B, which was valuable for investigating the adaptive plasticity of monocular blind macaque.

  13. Analyzing the effects of a single episode of neonatal maternal deprivation on metabolite profiles in rat brain: a proton nuclear magnetic resonance spectroscopy study.

    Science.gov (United States)

    Llorente, R; Villa, P; Marco, E M; Viveros, M P

    2012-01-10

    Animal models have greatly contributed to the understanding of neuropsychiatric disorders and have provided extensive evidence for the "neurodevelopmental hypothesis." In this regard, a single and prolonged episode (24 h) of early maternal deprivation early in life, on postnatal day 9, has been proposed as an animal model for the investigation of certain neuropsychiatric disorders, including schizophrenia. Since metabolic changes in hippocampus (HIP) and prefrontal cortex (PFC) have been described among schizophrenic patients by using ex vivo high-resolution magic angle spinning (HR-MAS) proton ((1)H) nuclear magnetic resonance spectroscopy, in the present study we aimed to investigate the effects of maternal deprivation (MD) on the metabolite profiles of the developing brain by using the HR-MAS technique. MD significantly altered the hippocampal and cortical metabolic profile of neonatal rats (PND 13) in a sex-dependent manner. Glutamine and glutamate (Glx) and taurine of male and female rat pups were altered in both brain areas analyzed. Differences in hippocampal phosphorylethanolamine have also been found as a function of the MD protocol. In addition, MD induced some other region- and sex-dependent effects, including changes in N-acetyl aspartate and total choline signals in the hippocampi of male pups. Present findings indicate a different brain metabolic profile in our animal model of early life stress suggesting its potential utility in the implementation of translational neuropsychiatric research.

  14. Relationship between Proton Magnetic Resonance Spectroscopy of Frontoinsular Gray Matter and Neurodevelopmental Outcomes in Very Low Birth Weight Children at the Age of 4.

    Directory of Open Access Journals (Sweden)

    Wojciech Durlak

    Full Text Available Very low birth weight is associated with long term neurodevelopmental complications. Macroscopic brain abnormalities in prematurity survivors have been investigated in several studies. However, there is limited data regarding local cerebral metabolic status and neurodevelopmental outcomes. The purpose of this study was to characterize the relationship between proton magnetic resonance spectra in basal ganglia, frontal white matter and frontoinsular gray matter, neurodevelopmental outcomes assessed with the Leiter scale and the Developmental Test of Visual Perception and selected socioeconomic variables in a cohort of very low birth weight children at the age of four. Children were divided in three groups based on the severity of neurodevelopmental impairment. There were no differences in spectroscopy in basal ganglia and frontal white matter between the groups. Lower concentrations of N-acetylaspartate (NAA, choline (Cho and myoinositol (mI were observed in the frontoinsular cortex of the left hemisphere in children with neurodevelopmental impairment compared to children with normal neurodevelopmental outcomes. Higher parental education, daycare attendance and breastfeeding after birth were associated with more favorable neurodevelopmental prognosis, whereas rural residence was more prevalent in children with moderate and severe impairment. Our study demonstrates the role of long term neurometabolic disruption in the left frontoinsular cortex and selected socioeconomic variables in determination of neurodevelopmental prognosis in prematurity survivors.

  15. Brain changes in long-term zen meditators using proton magnetic resonance spectroscopy and diffusion tensor imaging: a controlled study.

    Directory of Open Access Journals (Sweden)

    Nicolás Fayed

    Full Text Available INTRODUCTION: This work aimed to determine whether (1H magnetic resonance imaging (MRI, magnetic resonance spectroscopy (MRS, diffusion-weighted imaging (DWI and diffusion tensor imaging (DTI are correlated with years of meditation and psychological variables in long-term Zen meditators compared to healthy non-meditator controls. MATERIALS AND METHODS: Design. Controlled, cross-sectional study. Sample. Meditators were recruited from a Zen Buddhist monastery. The control group was recruited from hospital staff. Meditators were administered questionnaires on anxiety, depression, cognitive impairment and mindfulness. (1H-MRS (1.5 T of the brain was carried out by exploring four areas: both thalami, both hippocampi, the posterior superior parietal lobule (PSPL and posterior cingulate gyrus. Predefined areas of the brain were measured for diffusivity (ADC and fractional anisotropy (FA by MR-DTI. RESULTS: Myo-inositol (mI was increased in the posterior cingulate gyrus and Glutamate (Glu, N-acetyl-aspartate (NAA and N-acetyl-aspartate/Creatine (NAA/Cr was reduced in the left thalamus in meditators. We found a significant positive correlation between mI in the posterior cingulate and years of meditation (r = 0.518; p = .019. We also found significant negative correlations between Glu (r = -0.452; p = .045, NAA (r = -0.617; p = .003 and NAA/Cr (r = -0.448; P = .047 in the left thalamus and years of meditation. Meditators showed a lower Apparent Diffusion Coefficient (ADC in the left posterior parietal white matter than did controls, and the ADC was negatively correlated with years of meditation (r = -0.4850, p = .0066. CONCLUSIONS: The results are consistent with the view that mI, Glu and NAA are the most important altered metabolites. This study provides evidence of subtle abnormalities in neuronal function in regions of the white matter in meditators.

  16. Laser-accelerated proton beams as a new particle source

    Energy Technology Data Exchange (ETDEWEB)

    Nuernberg, Frank

    2010-11-15

    plasma physics group of the Technische Universitat Darmstadt initiated the development of a test stand to transport, focus and bunch rotate these beams by conventional ion optics and RF technology. The field strength of 7.5 T enabled collimation of protons with an energy of >10 MeV for the first time. In addition, the focusing capability of the solenoid provided a flux increase in the focal spot of about a factor of 174 at a distance of 40 cm from the source, compared to a beam without using the magnetic field. For a quantitative analysis of the experiment numerical simulations with the WarpRZ code were performed. The code, which was originally developed to study high current ion beams and aid in the pursuit of heavy-ion driven inertial confinement fusion, was modified to enable the use of laser-accelerated proton beams as particle source. The calculated energy-resolved beam parameters of RIS could be included, and the plasma simulation criteria were studied in detail. The geometrical boundaries of the experimental setup were used in the simulations. 2.99 x 10{sup 9} collimated protons in the energy range of 13.5{+-}1 MeV could be transported over a distance of 40 cm. In addition, 8.42 x 10{sup 9} protons in the energy range of 6.7{+-}0.2 MeV were focused into a spot of <2 mm in diameter. The transmission through the solenoid for both cases was about 18%. (orig.)

  17. Signal Feature Extraction and Quantitative Evaluation of Metal Magnetic Memory Testing for Oil Well Casing Based on Data Preprocessing Technique

    Directory of Open Access Journals (Sweden)

    Zhilin Liu

    2014-01-01

    Full Text Available Metal magnetic memory (MMM technique is an effective method to achieve the detection of stress concentration (SC zone for oil well casing. It can provide an early diagnosis of microdamages for preventive protection. MMM is a natural space domain signal which is weak and vulnerable to noise interference. So, it is difficult to achieve effective feature extraction of MMM signal especially under the hostile subsurface environment of high temperature, high pressure, high humidity, and multiple interfering sources. In this paper, a method of median filter preprocessing based on data preprocessing technique is proposed to eliminate the outliers point of MMM. And, based on wavelet transform (WT, the adaptive wavelet denoising method and data smoothing arithmetic are applied in testing the system of MMM. By using data preprocessing technique, the data are reserved and the noises of the signal are reduced. Therefore, the correct localization of SC zone can be achieved. In the meantime, characteristic parameters in new diagnostic approach are put forward to ensure the reliable determination of casing danger level through least squares support vector machine (LS-SVM and nonlinear quantitative mapping relationship. The effectiveness and feasibility of this method are verified through experiments.

  18. Quantitation and localization of regional body fat distribution--a comparison between magnetic resonance imaging and somatometry.

    Science.gov (United States)

    Sharma, R C; Kramsch, D M; Lee, P L; Colletti, P; Jiao, Q

    1996-03-01

    The emerging concept that various fat compartments are metabolically active and play separate and decisive roles in the pathogenesis of coronary atherosclerosis, hypertension, insulin resistance, diabetes and stroke, has given obesity research a new direction. Of particular interest is the relative amount of intra-abdominal fat thought to be responsible for the metabolic complications. We studied the precise fat distribution and its correlations with the metabolic parameters in 44 non-human primates (Macaca fascicularis). Intra-abdominal, subcutaneous, and total abdominal fat (IAF, SAF, TAF) were assessed by magnetic resonance imaging (MRI) and somatometry. Quantitative computer analyses of abdominal MRI scans revealed predominant IAF distribution. Box plot analysis of IAF and SAF revealed wide diversity in the amounts of fat, especially in monkeys with body mass index (BMI) < 30 kg/m2. Primates with similar BMI in each quartile revealed an extensive heterogeneity in IAF as well as SAF. Numerous significant correlations within site-specific somatometric measurements as well as within the MRI determinants of abdominal fat were seen. However, only body weight correlated with IAF and skinfolds could predict SAF. After adjusting for body weight, partial correlation analysis showed a significant correlation (P < 0.05) between total cholesterol and IAF. MRI revealed considerable heterogeneity of IAF, SAF and TAF in cohort of primates believed to be homogeneous by somatometric definition. Male cynomolgus monkeys appear to be a valuable model for a systematic evaluation of fat. Individuals with identical body weight and height may show a diverse pattern of fat distribution.

  19. Validation of Body Condition Indices and Quantitative Magnetic Resonance in Estimating Body Composition in a Small Lizard

    Science.gov (United States)

    WARNER, DANIEL A.; JOHNSON, MARIA S.; NAGY, TIM R.

    2017-01-01

    Measurements of body condition are typically used to assess an individual’s quality, health, or energetic state. Most indices of body condition are based on linear relationships between body length and mass. Although these indices are simple to obtain, nonlethal, and useful indications of energetic state, their accuracy at predicting constituents of body condition (e.g., fat and lean mass) are often unknown. The objectives of this research were to (1) validate the accuracy of another simple and noninvasive method, quantitative magnetic resonance (QMR), at estimating body composition in a small-bodied lizard, Anolis sagrei, and (2) evaluate the accuracy of two indices of body condition (based on length–mass relationships) at predicting body fat, lean, and water mass. Comparisons of results from QMR scans to those from chemical carcass analysis reveal that QMR measures body fat, lean, and water mass with excellent accuracy in male and female lizards. With minor calibration from regression equations, QMR will be a reliable method of estimating body composition of A. sagrei. Body condition indices were positively related to absolute estimates of each constituent of body composition, but these relationships showed considerable variation around regression lines. In addition, condition indices did not predict fat, lean, or water mass when adjusted for body mass. Thus, our results emphasize the need for caution when interpreting body condition based upon linear measurements of animals. Overall, QMR provides an alternative noninvasive method for accurately measuring fat, lean, and water mass in these small-bodied animals. PMID:28035770

  20. Chemical purity using quantitative (1)H-nuclear magnetic resonance: a hierarchical Bayesian approach for traceable calibrations.

    Science.gov (United States)

    Toman, Blaza; Nelson, Michael A; Lippa, Katrice A

    2016-01-01

    Chemical purity assessment using quantitative (1)H-nuclear magnetic resonance spectroscopy is a method based on ratio references of mass and signal intensity of the analyte species to that of chemical standards of known purity. As such, it is an example of a calculation using a known measurement equation with multiple inputs. Though multiple samples are often analyzed during purity evaluations in order to assess measurement repeatability, the uncertainty evaluation must also account for contributions from inputs to the measurement equation. Furthermore, there may be other uncertainty components inherent in the experimental design, such as independent implementation of multiple calibration standards. As such, the uncertainty evaluation is not purely bottom up (based on the measurement equation) or top down (based on the experimental design), but inherently contains elements of both. This hybrid form of uncertainty analysis is readily implemented with Bayesian statistical analysis. In this article we describe this type of analysis in detail and illustrate it using data from an evaluation of chemical purity and its uncertainty for a folic acid material.

  1. Quantitative Ultrasound for Staging of Hepatic Steatosis in Patients on Home Parenteral Nutrition Validated with Magnetic Resonance Spectroscopy: A Feasibility Study.

    Science.gov (United States)

    Weijers, Gerrit; Wanten, Geert; Thijssen, Johan M; van der Graaf, Marinette; de Korte, Chris L

    2016-03-01

    Patients on home parenteral nutrition are at risk for developing liver dysfunction, which is due partly to the accumulation of lipids in the liver (steatosis) and may progress to end-stage liver disease with overt liver failure. Therefore, a timely diagnosis with easy access to repeated assessment of the degree of liver steatosis is of great importance. A pilot study was performed in 14 patients on long-term home parenteral nutrition using the computer-aided ultrasound method. Ultrasound radio frequency data were acquired using a phased array transducer and were converted into conventional B-mode images. All patients were subjected to proton magnetic resonance spectroscopy measurement of liver fat content for reference. Computer-aided ultrasound parameters similar to those in a previous validation study in cows revealed significant correlations with fat content measured by magnetic resonance spectroscopy. The most significant parameters were the residual attenuation coefficient (R = 0.95, p ultrasound for staging of hepatic steatosis.

  2. DIFFERENTIATION OF AURANTII FRUCTUS IMMATURUS AND FRUCTUS PONICIRI TRIFOLIATAE IMMATURUS BY FLOW-INJECTION WITH ULTRAVIOLET SPECTROSCOPIC DETECTION AND PROTON NUCLEAR MAGNETIC RESONANCE USING PARTIAL LEAST-SQUARES DISCRIMINANT ANALYSIS.

    Science.gov (United States)

    Zhang, Mengliang; Zhao, Yang; Harrington, Peter de B; Chen, Pei

    2016-03-01

    Two simple fingerprinting methods, flow-injection coupled to ultraviolet spectroscopy and proton nuclear magnetic resonance, were used for discriminating between Aurantii fructus immaturus and Fructus poniciri trifoliatae immaturus. Both methods were combined with partial least-squares discriminant analysis. In the flow-injection method, four data representations were evaluated: total ultraviolet absorbance chromatograms, averaged ultraviolet spectra, absorbance at 193, 205, 225, and 283 nm, and absorbance at 225 and 283 nm. Prediction rates of 100% were achieved for all data representations by partial least-squares discriminant analysis using leave-one-sample-out cross-validation. The prediction rate for the proton nuclear magnetic resonance data by partial least-squares discriminant analysis with leave-one-sample-out cross-validation was also 100%. A new validation set of data was collected by flow-injection with ultraviolet spectroscopic detection two weeks later and predicted by partial least-squares discriminant analysis models constructed by the initial data representations with no parameter changes. The classification rates were 95% with the total ultraviolet absorbance chromatograms datasets and 100% with the other three datasets. Flow-injection with ultraviolet detection and proton nuclear magnetic resonance are simple, high throughput, and low-cost methods for discrimination studies.

  3. Quantitative evaluation of perfusion magnetic resonance imaging hyper-acute ischemic stroke patients comparison with 1.5T and 3.0T units

    Energy Technology Data Exchange (ETDEWEB)

    Goo, Eun Hoe [Dept. of Radiological Science, Cheongju University, Cheongju (Korea, Republic of); Moon, Il Bong; Dong, Kyung Rae [Dept. of Radiological Technology, Gwangju Health University, Gwangju (Korea, Republic of)

    2017-02-15

    Perfusion magnetic resonance image of biological mechanism are independent of magnetic field strength in hyper acute ischemic stroke. 3.0 T magnetic field, however, does affect the SNRs (signal to noise ratio) and artifacts of PMRI (perfusion magnetic resonance image), which basically will influence the quantitative of PMRI. In this study, the effects of field strength on PMRI are analyzed. The effects of the diseases also are discussed. PMRI in WM (white matter), GM (gray matter), hyper acute ischemic stroke were companied with 1.5 T and 3.0 T on SNR. PMRI also was compared to the SI difference after setting ROI (region of interest) in left and right b side of the brain. In conclusion, the SNRs and SI of the 3.0 T PMRI showed higher than those at 1.5 T. In summary, PMRI studies at 3.0 T is provided significantly improved perfusion evaluation when comparing with 1.5 T.

  4. Association between proton magnetic resonance spectroscopy measurements and CAG repeat number in patients with spinocerebellar ataxias 2, 3, or 6.

    Directory of Open Access Journals (Sweden)

    Po-Shan Wang

    Full Text Available The aim of this study was to correlate magnetic resonance spectroscopy (MRS measurements, including that for the N-acetyl aspartate (NAA/creatine (Cr ratio in the vermis (denoted V-NAA, right cerebellar hemisphere (R-NAA, and left (L-NAA cerebellar hemisphere, with the clinical scale for the assessment and rating of ataxia (SARA score for patients with spinocerebellar ataxia (SCA types 2, 3, and 6. A total of 24 patients with SCA2, 48 with SCA3, and 16 with SCA6 were recruited; 12 patients with SCA2, 43 with SCA3, and 8 with SCA6 underwent detailed magnetic resonance neuroimaging. Forty-four healthy, age-matched individuals without history of neurologic disease served as control subjects. V-NAA and patient age were used to calculate the predicted age at which a patient with SCA2 or SCA3 would reach an onset V-NAA value. Results showed the following: the NAA/Cr ratio decreased with increasing age in patients with SCA but not in control subjects; the SARA score increased progressively with age and duration of illness; V-NAA showed a better correlation with SARA score than R-NAA in patients with SCA2 or SCA3; the ratio of age to V-NAA correlated well with CAG repeat number; the retrospectively predicted age of onset for SCA2 and SCA3 was consistent with patient-reported age of onset; R-NAA showed a better correlation with SARA score than V-NAA in patients with SCA6; V-NAA and R-NAA correlated with clinical severity (SARA score in patients with SCA. The correlation between CAG repeat number and age could be expressed as a simple linear function, which might explain previous observations claiming that the greater the CAG repeat number, the earlier the onset of illness and the faster the disease progression. These findings support the use of MRS values to predict age of disease onset and to retrospectively evaluate the actual age of disease onset in SCA.

  5. Association between proton magnetic resonance spectroscopy measurements and CAG repeat number in patients with spinocerebellar ataxias 2, 3, or 6.

    Science.gov (United States)

    Wang, Po-Shan; Chen, Hung-Chieh; Wu, Hsiu-Mei; Lirng, Jiing-Feng; Wu, Yu-Te; Soong, Bing-Wen

    2012-01-01

    The aim of this study was to correlate magnetic resonance spectroscopy (MRS) measurements, including that for the N-acetyl aspartate (NAA)/creatine (Cr) ratio in the vermis (denoted V-NAA), right cerebellar hemisphere (R-NAA), and left (L-NAA) cerebellar hemisphere, with the clinical scale for the assessment and rating of ataxia (SARA) score for patients with spinocerebellar ataxia (SCA) types 2, 3, and 6. A total of 24 patients with SCA2, 48 with SCA3, and 16 with SCA6 were recruited; 12 patients with SCA2, 43 with SCA3, and 8 with SCA6 underwent detailed magnetic resonance neuroimaging. Forty-four healthy, age-matched individuals without history of neurologic disease served as control subjects. V-NAA and patient age were used to calculate the predicted age at which a patient with SCA2 or SCA3 would reach an onset V-NAA value. Results showed the following: the NAA/Cr ratio decreased with increasing age in patients with SCA but not in control subjects; the SARA score increased progressively with age and duration of illness; V-NAA showed a better correlation with SARA score than R-NAA in patients with SCA2 or SCA3; the ratio of age to V-NAA correlated well with CAG repeat number; the retrospectively predicted age of onset for SCA2 and SCA3 was consistent with patient-reported age of onset; R-NAA showed a better correlation with SARA score than V-NAA in patients with SCA6; V-NAA and R-NAA correlated with clinical severity (SARA score) in patients with SCA. The correlation between CAG repeat number and age could be expressed as a simple linear function, which might explain previous observations claiming that the greater the CAG repeat number, the earlier the onset of illness and the faster the disease progression. These findings support the use of MRS values to predict age of disease onset and to retrospectively evaluate the actual age of disease onset in SCA.

  6. Predictors of CNS Injury as Measured by Proton Magnetic Resonance Spectroscopy in the Setting of Chronic HIV infection and CART

    Science.gov (United States)

    Harezlak, J; Cohen, R; Gongvatana, A; Taylor, M; Buchthal, S; Schifitto, G; Zhong, J; Daar, ES; Alger, J; Brown, M; Singer, E; Campbell, TB; McMahon, D; So, YT; Yiannoutsos, CT; Navia, BA

    2014-01-01

    The reasons for persistent brain dysfunction in chronically HIV-infected persons on stable combined antiretroviral therapies (CART) remain unclear. Host and viral factors along with their interactions were examined in 260 HIV-infected subjects who underwent magnetic resonance spectroscopy (MRS) Metabolite concentrations (NAA/Cr, Cho/Cr, MI/Cr and Glx/Cr) were measured in the basal ganglia, the frontal white matter and grey matter and the best predictive models were selected using a bootstrap-enhanced Akaike Information Criterion (AIC). Depending on the metabolite and brain region, age, race, HIV RNA concentration, ADC stage, duration of HIV infection, nadir CD4, and/or their interactions were predictive of metabolite concentrations, particularly the basal ganglia NAA/Cr and the mid-frontal NAA/Cr and Glx/Cr whereas current CD4 and the CPE index rarely or did not predict these changes. These results show for the first time that host and viral factors related to both current and past HIV status contribute to persisting cerebral metabolite abnormalities and provide a framework for further understanding neurological injury in the setting of chronic and stable disease. PMID:24696364

  7. CHBPR Proton Magnetic Resonance Spectroscopy Detection of Neurotransmitters in Dorsomedial Medulla Correlate with Spontaneous Baroreceptor Reflex Function

    Science.gov (United States)

    Garcia-Espinosa, Maria A.; Shaltout, Hossam A.; Olson, John; Westwood, Brian M.; Robbins, Mike E.; Link, Kerry; Diz, Debra I.

    2010-01-01

    Control of heart rate variability (HRV) via modulation of sympathovagal balance is a key function of nucleus tractus solitarii (nTS) and dorsal motor nucleus of the vagus localized in the dorsomedial medulla oblongata. Normal blood pressure regulation involves precise balance of glutamate-glutamine-GABA (Glu-Gln-GABA) transmitter systems, and angiotensin (Ang) II modulates these transmitters to produce tonic suppression of reflex function. It is not known, however, whether other brain transmitters/metabolites are indicators of baroreflex function. This study establishes the concept that comprehensive baseline transmitter/metabolite profiles obtained using in vivo 1H Magnetic Resonance Spectroscopy (1H MRS) in rats with well characterized differences in resting blood pressure and baroreflex function can be used as indices of autonomic balance or baroreflex sensitivity. Glu concentration in dorsal medulla is significantly higher in ASrAogen rats compared to either SD and (mRen2)27. Glu levels and the ratio of Glu/Gln correlated positively with indices of higher vagal tone consistent with the importance of these neurotransmitters in baroreflex function. Interestingly, the levels of choline containing metabolites showed a significant positive correlation with spontaneous baroreflex sensitivity and a negative correlation with sympathetic tone. Thus, we demonstrate the concept that non-invasive assessment of neurochemical biomarkers may be used as an index of baroreflex sensitivity. PMID:20065146

  8. Improved measurement of labile proton concentration-weighted chemical exchange rate (k(ws)) with experimental factor-compensated and T(1) -normalized quantitative chemical exchange saturation transfer (CEST) MRI.

    Science.gov (United States)

    Wu, Renhua; Liu, Charng-Ming; Liu, Philip K; Sun, Phillip Zhe

    2012-01-01

    Chemical exchange saturation transfer (CEST) MRI enables measurement of dilute CEST agents and microenvironment properties such as pH and temperature, holding great promise for in vivo applications. However, because of confounding concomitant radio frequency (RF) irradiation and relaxation effects, the CEST-weighted MRI contrast may not fully characterize the underlying CEST phenomenon. We postulated that the accuracy of quantitative CEST MRI could be improved if the experimental factors (labeling efficiency and RF spillover effect) were estimated and taken into account. Specifically, the experimental factor was evaluated as a function of exchange rate and CEST agent concentration ratio, which remained relatively constant for intermediate RF irradiation power levels. Hence, the experimental factors can be calculated based on the reasonably estimated exchange rate and labile proton concentration ratio, which significantly improved quantification. The simulation was confirmed with creatine phantoms of serially varied concentration titrated to the same pH, whose reverse exchange rate (k(ws)) was found to be linearly correlated with the concentration. In summary, the proposed solution provides simplified yet reasonably accurate quantification of the underlying CEST system, which may help guide the ongoing development of quantitative CEST MRI.

  9. Proton conduction in biopolymer exopolysaccharide succinoglycan

    Energy Technology Data Exchange (ETDEWEB)

    Kweon, Jin Jung [Department of Physics, Korea University, Seoul 136-713 (Korea, Republic of); National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310 (United States); Lee, Kyu Won; Kim, Hyojung; Lee, Cheol Eui, E-mail: rscel@korea.ac.kr [Department of Physics, Korea University, Seoul 136-713 (Korea, Republic of); Jung, Seunho [Department of Bioscience and Biotechnology and UBITA, Konkuk University, Seoul 143-701 (Korea, Republic of); Kwon, Chanho [Naraebio Research Laboratories, 177 Dangha-ri, Bongdam-eup, Hawseong-si 445-892 (Korea, Republic of)

    2014-07-07

    Protonic currents play a vital role in electrical signalling in living systems. It has been suggested that succinoglycan plays a specific role in alfalfa root nodule development, presumably acting as the signaling molecules. In this regard, charge transport and proton dynamics in the biopolymer exopolysaccharide succinoglycan have been studied by means of electrical measurements and nuclear magnetic resonance (NMR) spectroscopy. In particular, a dielectric dispersion in the system has revealed that the electrical conduction is protonic rather electronic. Besides, our laboratory- and rotating-frame {sup 1}H NMR measurements have elucidated the nature of the protonic conduction, activation of the protonic motion being associated with a glass transition.

  10. Proton conduction in biopolymer exopolysaccharide succinoglycan

    Science.gov (United States)

    Kweon, Jin Jung; Lee, Kyu Won; Kim, Hyojung; Lee, Cheol Eui; Jung, Seunho; Kwon, Chanho

    2014-07-01

    Protonic currents play a vital role in electrical signalling in living systems. It has been suggested that succinoglycan plays a specific role in alfalfa root nodule development, presumably acting as the signaling molecules. In this regard, charge transport and proton dynamics in the biopolymer exopolysaccharide succinoglycan have been studied by means of electrical measurements and nuclear magnetic resonance (NMR) spectroscopy. In particular, a dielectric dispersion in the system has revealed that the electrical conduction is protonic rather electronic. Besides, our laboratory- and rotating-frame 1H NMR measurements have elucidated the nature of the protonic conduction, activation of the protonic motion being associated with a glass transition.

  11. Reproducibility and accuracy of quantitative assessment of articular cartilage volume measurements with 3.0 tesla magnetic resonance imaging

    Institute of Scientific and Technical Information of China (English)

    XING Wei; SHENG Jing; CHEN Wen-hua; TIAN Jian-ming; ZHANG Li-rong; WANG Dong-qing

    2011-01-01

    Background Quantitative magnetic resonance imaging (qMRI) of articular cartilage represents a powerful tool in osteoarthritis research, but has so far been confined to a field strength of 1.5 T. The aim of the study was to determine the reproducibility and accuracy of qMRI assessments of the knee cartilage volume by comparing quantitative swine cartilage volumes of the sagittal (sag) multi echo data imagine combination water-excitation (MEDICwe) sequence and the fast low-angle shoot water-excitation (FLASHwe) sequence at 3.0-T MRI to directly measured volumes (DMV) of the surgically removed articular cartilage.Methods Test-retest MRI was acquired in 20 swine knees. Two sag FLASHwe sequences and two sag MEDICwe sequences (spatial resolution 0.4 mm × 0.4 mm × 1.0 mm of 3-dimension (3D) were acquired at 3-T MRI in a knee.Articular cartilage volume was calculated from 3D reformations of the MRI by using a manual program. Calculated volumes were compared with DMV of the surgically removed articular cartilage. Knee joint cartilage plates were quantified paired in order.Results In the knee joint of swine, reproducibility errors (paired analysis) for cartilage volume were 2.5% to 3.2% with sag FLASHwe, and 1.6% to 3.0% with sag MEDICwe. Correlation coefficients between results obtained with qMRI and DMV ranged from 0.90 to 0.98 for cartilage volume. Systematic pairwise difference between results obtained with qMRI and DMV ranged from -1.1% to 2.8%. Random pairwise differences between results obtained with qMRI and DMV ranged from (2.9 ±2.4)% to (6.8±4.5)%.Conclusions FLASHwe and MEDICwe sequences permit highly accurate and reproducible analysis of cartilage volume in the knee joints of swine at 3-T MRI. Cartilage volume reproducibility for the MEDICwe data is slightly higher than the FLASHwe data.

  12. Optical diagnostics of mercury jet for an intense proton target.

    Science.gov (United States)

    Park, H; Tsang, T; Kirk, H G; Ladeinde, F; Graves, V B; Spampinato, P T; Carroll, A J; Titus, P H; McDonald, K T

    2008-04-01

    An optical diagnostic system is designed and constructed for imaging a free mercury jet interacting with a high intensity proton beam in a pulsed high-field solenoid magnet. The optical imaging system employs a backilluminated, laser shadow photography technique. Object illumination and image capture are transmitted through radiation-hard multimode optical fibers and flexible coherent imaging fibers. A retroreflected illumination design allows the entire passive imaging system to fit inside the bore of the solenoid magnet. A sequence of synchronized short laser light pulses are used to freeze the transient events, and the images are recorded by several high speed charge coupled devices. Quantitative and qualitative data analysis using image processing based on