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Sample records for 4t proton magnetic

  1. In vivo proton magnetic resonance spectroscopic imaging of the healthy human brain at 9.4 T: initial experience.

    PubMed

    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.

  2. Reduced Brain GABA in Primary Insomnia: Preliminary Data from 4T Proton Magnetic Resonance Spectroscopy (1H-MRS)

    PubMed Central

    Winkelman, John W.; Buxton, Orfeu M.; Jensen, J. Eric; Benson, Kathleen L.; O'Connor, Shawn P.; Wang, Wei; Renshaw, Perry F.

    2008-01-01

    Study Objectives: Both basic and clinical data suggest a potential significant role for GABA in the etiology and maintenance of primary insomnia (PI). Proton magnetic resonance spectroscopy (1H-MRS) can non-invasively determine GABA levels in human brain. Our objective was to assess GABA levels in unmedicated individuals with PI, using 1H-MRS. Design and Setting: Matched-groups, cross-sectional study conducted at two university-based hospitals. Participants: Sixteen non-medicated individuals (8 women) with PI (mean age = 37.3 +/− 8.1) and 16 (7 women) well-screened normal sleepers (mean age = 37.6 +/− 4.5). Methods and Measurements: PI was established with an unstructured clinical interview, a Structured Clinical Interview for DSM-IV (SCID), sleep diary, actigraphy and polysomnography (PSG). 1H-MRS data were collected on a Varian 4 Tesla magnetic resonance imaging/spectroscopy scanner. Global brain GABA levels were averaged from samples in the basal ganglia, thalamus, and temporal, parietal, and occipital white-matter and cortex. Results: Average brain GABA levels were nearly 30% lower in patients with PI (.18 +/− .06) compared to controls (.25 +/− .11). GABA levels were negatively correlated with wake after sleep onset (WASO) on two independent PSGs (r = −0.71, p = 0.0024 and −0.70, p = 0.0048). Conclusions: Our preliminary finding of a global reduction in GABA in non-medicated individuals with PI is the first demonstration of a neurochemical difference in the brains of those with PI compared to normal sleeping controls. 1H-MRS is a valuable tool to assess GABA in vivo, and may provide a means to shed further light on the neurobiology of insomnia. Citation: Winkelman JW; Buxton OM; Jensen JE; Benson KL; O'Connor SP; Wang W; Renshaw PF. Reduced brain GABA in primary insomnia: preliminary data from 4T proton magnetic resonance spectroscopy (1H-MRS). SLEEP 2008;31(11):1499–1506. PMID:19014069

  3. EEG acquisition in ultra-high static magnetic fields up to 9.4 T.

    PubMed

    Neuner, Irene; Warbrick, Tracy; Arrubla, Jorge; Felder, Jörg; Celik, Avdo; Reske, Martina; Boers, Franks; Shah, N Jon

    2013-03-01

    The simultaneous acquisition of electroencephalographic (EEG) and functional magnetic resonance imaging (fMRI) data has gained momentum in recent years due to the synergistic effects of the two modalities with regard to temporal and spatial resolution. Currently, only EEG-data recorded in fields of up to 7 T have been reported. We investigated the feasibility of recording EEG inside a 9.4 T static magnetic field, specifically to determine whether meaningful EEG information could be recovered from the data after removal of the cardiac-related artefact. EEG-data were recorded reliably and reproducibly at 9.4 T and the cardiac-related artefact increased in amplitude with increasing B0, as expected. Furthermore, we were able to correct for the cardiac-related artefact and identify auditory event related responses at 9.4 T in 75% of subjects using independent component analysis (ICA). Also by means of ICA we detected event related spectral perturbations (ERSP) in subjects at 9.4 T in response to opening/closing the eyes comparable with the response at 0 T. Overall our results suggest that it is possible to record meaningful EEG data at ultra-high magnetic fields. The simultaneous EEG-fMRI approach at ultra-high-fields opens up the horizon for investigating brain dynamics at a superb spatial resolution and a temporal resolution in the millisecond domain. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. Quench protection design of a 9.4 T whole-body MRI superconducting magnet

    NASA Astrophysics Data System (ADS)

    Chen, Shunzhong; Li, Yi; Dai, Yinming; Lei, Yuanzhong; Yan, Luguang

    2014-02-01

    A 9.4 T MRI superconducting magnet with a 800 mm clear warm bore in diameter is designed and fabricated for bioscience research. The superconducting magnet consisting of five coaxial solenoid coils is fabricated with NbTi Wire-in-Channel (WIC) conductor where the ratios of copper to non-copper are from 5 to 10. The four compensation solenoid coils are with rectangular NbTi/Cu strand wires. The magnet will be operated in a relative low nominal current of 224.5 A with a high level of stored energy, about 138 MJ. A protection method with the cold diodes and resistors in series across the subdivided sections and active trigger heater to accelerate quench is adopted to avoid the damage of the magnet. In the paper, the quench simulation results of currents, voltages and hot-spot temperatures based on the protection scheme are analyzed in details.

  5. Subchronic in vivo effects of a high static magnetic field (9.4 T) in rats.

    PubMed

    High, W B; Sikora, J; Ugurbil, K; Garwood, M

    2000-07-01

    The potential adverse biologic effects of sub chronic (cumulatively 10 weeks) exposure to a high magnetic field (9.4 T) were evaluated in young adult male and female Fischer rats as well as in their progeny. Biologic end points in adult rats included changes in daily clinical observations; spatial memory tests; weekly heart rates, body weights, food and water consumption, and the feed efficiency ratio; terminal hematologic, blood biochemical and urinary parameter changes; gross pathologic findings; and major organ weights. In offspring, biologic end points included the gestation period, number of live births, number of pups, ratio of male to female pups/litter; postnatal time period of eye opening; birth and weekly body weights, behavioral changes, central nervous system responses, as well as hematologic, blood biochemistry, and urinary parameter changes; and gross pathologic findings. Findings from this study showed that there were no adverse biologic effects in male and female adult rats or their progeny that could be attributed to 10-week exposure to a 9.4-T static magnetic field.

  6. MR imaging of the amide-proton transfer effect and the pH-insensitive nuclear overhauser effect at 9.4 T.

    PubMed

    Jin, Tao; Wang, Ping; Zong, Xiaopeng; Kim, Seong-Gi

    2013-03-01

    The amide proton transfer (APT) effect has emerged as a unique endogenous molecular imaging contrast mechanism with great clinical potentials. However, in vivo quantitative mapping of APT using the conventional asymmetry analysis is difficult due to the confounding nuclear Overhauser effect (NOE) and the asymmetry of the magnetization transfer effect. Here, we showed that the asymmetry of magnetization transfer contrast from immobile macromolecules is highly significant, and the wide spectral separation associated with a high magnetic field of 9.4 T delineates APT and NOE peaks in a Z-spectrum. Therefore, high-resolution apparent APT and NOE maps can be obtained from measurements at three offsets. The apparent APT value was greater in gray matter compared to white matter in normal rat brain and was sensitive to tissue acidosis and correlated well with apparent diffusion coefficient in the rat focal ischemic brain. In contrast, no ischemia-induced contrast was observed in the apparent NOE map. The concentration dependence and the pH insensitivity of NOE were confirmed in phantom experiments. Our results demonstrate that in vivo apparent APT and NOE maps can be easily obtained at high magnetic fields and the pH-insensitive NOE may be a useful indicator of mobile macromolecular contents. Copyright © 2012 Wiley Periodicals, Inc.

  7. Multicenter study of subjective acceptance during magnetic resonance imaging at 7 and 9.4 T.

    PubMed

    Rauschenberg, Jaane; Nagel, Armin M; Ladd, Susanne C; Theysohn, Jens M; Ladd, Mark E; Möller, Harald E; Trampel, Robert; Turner, Robert; Pohmann, Rolf; Scheffler, Klaus; Brechmann, André; Stadler, Jörg; Felder, Jörg; Shah, N Jon; Semmler, Wolfhard

    2014-05-01

    The aims of this study were to investigate the subjective discomfort and sensory side effects during ultrahigh field (UHF) magnetic resonance imaging (MRI) examinations in a large-scale study and to evaluate differences between magnetic resonance (MR) sites. Four MR sites with a 7-T MR system and 2 MR sites with a 9.4-T MR system participated in this multicenter study with a total number of 3457 completed questionnaires on causes of discomfort and sensations during the examination. For a pooled retrospective analysis of the results from the partially different questionnaires, all data were adapted to an answer option with a 4-point scale (0 = no discomfort/side effect, 3 = very unpleasant/very strong sensation). To differentiate effects evoked by the low-frequency time-varying magnetic fields due to movement through the static magnetic field, most questionnaires separated the manifestation of sensory side effects during movement on the patient table from manifestation while lying still in the isocenter. In general, a high acceptance of UHF examinations was found, where in 82% of the completed questionnaires, the subjects stated the examination to be at least tolerable. Although in 7.6% of the questionnaires, subjects felt discomfort during the examination, only 0.9% of the image acquisitions had to be terminated prematurely. No adverse events occurred in any of the examinations. Only 1% of the subjects were unwilling to undergo further UHF MRI examinations. Examination duration was the most complained cause of discomfort, followed by acoustic noise and lying still. All magnetic-field-related sensations were more pronounced when moving the patient table versus the isocenter position (19%/2% of the subjects felt unpleasant vertigo during the moving/stationary state). In general, vertigo was the most often stated sensory side effect and was more pronounced at 9.4 T compared with 7 T. However, the results varied substantially among the different sites. The high levels

  8. MR imaging of the Amide-Proton Transfer effect and the pH-insensitive Nuclear Overhauser Effect at 9.4 T

    PubMed Central

    Jin, Tao; Wang, Ping; Zong, Xiaopeng; Kim, Seong-Gi

    2012-01-01

    The amide proton transfer (APT) effect has emerged as a unique endogenous molecular imaging contrast mechanism with great clinical potentials. However, in vivo quantitative mapping of APT using the conventional asymmetry analysis is difficult due to the confounding Nuclear Overhauser Effect (NOE) and the asymmetry of the magnetization transfer (MT) effect. Here we showed that the asymmetry of MT contrast from immobile macromolecules is highly significant, and the wide spectral separation associated with a high magnetic field of 9.4 T delineates APT and NOE peaks in a Z-spectrum. Therefore, high resolution apparent APT and NOE maps can be obtained from measurements at three offsets. The apparent APT value was greater in gray matter compared to white matter in normal rat brain, and was sensitive to tissue acidosis and correlated well with ADC in the rat focal ischemic brain. In contrast, no ischemia-induced contrast was observed in the apparent NOE map. The concentration-dependence and the pH insensitivity of NOE were confirmed in phantom experiments. Our results demonstrate that in vivo apparent APT and NOE maps can be easily obtained at high magnetic fields, and the pH-insensitive NOE may be a useful indicator of mobile macromolecular contents. PMID:22577042

  9. In vivo magnetic resonance microscopy of Drosophilae at 9.4 T.

    PubMed

    Même, Sandra; Joudiou, Nicolas; Szeremeta, Frédéric; Mispelter, Joël; Louat, Fanny; Decoville, Martine; Locker, Daniel; Beloeil, Jean-Claude

    2013-01-01

    In preclinical research, genetic studies have made considerable progress as a result of the development of transgenic animal models of human diseases. Consequently, there is now a need for higher resolution MRI to provide finer details for studies of small animals (rats, mice) or very small animals (insects). One way to address this issue is to work with high-magnetic-field spectrometers (dedicated to small animal imaging) with strong magnetic field gradients. It is also necessary to develop a complete methodology (transmit/receive coil, pulse sequence, fixing system, air supply, anesthesia capabilities, etc.). In this study, we developed noninvasive protocols, both in vitro and in vivo (from coil construction to image generation), for drosophila MRI at 9.4 T. The 10 10 80-μm resolution makes it possible to visualize whole drosophila (head, thorax, abdomen) and internal organs (ovaries, longitudinal and transverse muscles, bowel, proboscis, antennae and optical lobes). We also provide some results obtained with a Drosophila model of muscle degeneration. This opens the way for new applications of structural genetic modification studies using MRI of drosophila. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Recording Visual Evoked Potentials and Auditory Evoked P300 at 9.4T Static Magnetic Field

    PubMed Central

    Hahn, David; Boers, Frank; Shah, N. Jon

    2013-01-01

    Simultaneous recording of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) has shown a number of advantages that make this multimodal technique superior to fMRI alone. The feasibility of recording EEG at ultra-high static magnetic field up to 9.4T was recently demonstrated and promises to be implemented soon in fMRI studies at ultra high magnetic fields. Recording visual evoked potentials are expected to be amongst the most simple for simultaneous EEG/fMRI at ultra-high magnetic field due to the easy assessment of the visual cortex. Auditory evoked P300 measurements are of interest since it is believed that they represent the earliest stage of cognitive processing. In this study, we investigate the feasibility of recording visual evoked potentials and auditory evoked P300 in a 9.4T static magnetic field. For this purpose, EEG data were recorded from 26 healthy volunteers inside a 9.4T MR scanner using a 32-channel MR compatible EEG system. Visual stimulation and auditory oddball paradigm were presented in order to elicit evoked related potentials (ERP). Recordings made outside the scanner were performed using the same stimuli and EEG system for comparison purposes. We were able to retrieve visual P100 and auditory P300 evoked potentials at 9.4T static magnetic field after correction of the ballistocardiogram artefact using independent component analysis. The latencies of the ERPs recorded at 9.4T were not different from those recorded at 0T. The amplitudes of ERPs were higher at 9.4T when compared to recordings at 0T. Nevertheless, it seems that the increased amplitudes of the ERPs are due to the effect of the ultra-high field on the EEG recording system rather than alteration in the intrinsic processes that generate the electrophysiological responses. PMID:23650538

  11. Recording visual evoked potentials and auditory evoked P300 at 9.4T static magnetic field.

    PubMed

    Arrubla, Jorge; Neuner, Irene; Hahn, David; Boers, Frank; Shah, N Jon

    2013-01-01

    Simultaneous recording of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) has shown a number of advantages that make this multimodal technique superior to fMRI alone. The feasibility of recording EEG at ultra-high static magnetic field up to 9.4 T was recently demonstrated and promises to be implemented soon in fMRI studies at ultra high magnetic fields. Recording visual evoked potentials are expected to be amongst the most simple for simultaneous EEG/fMRI at ultra-high magnetic field due to the easy assessment of the visual cortex. Auditory evoked P300 measurements are of interest since it is believed that they represent the earliest stage of cognitive processing. In this study, we investigate the feasibility of recording visual evoked potentials and auditory evoked P300 in a 9.4 T static magnetic field. For this purpose, EEG data were recorded from 26 healthy volunteers inside a 9.4 T MR scanner using a 32-channel MR compatible EEG system. Visual stimulation and auditory oddball paradigm were presented in order to elicit evoked related potentials (ERP). Recordings made outside the scanner were performed using the same stimuli and EEG system for comparison purposes. We were able to retrieve visual P100 and auditory P300 evoked potentials at 9.4 T static magnetic field after correction of the ballistocardiogram artefact using independent component analysis. The latencies of the ERPs recorded at 9.4 T were not different from those recorded at 0 T. The amplitudes of ERPs were higher at 9.4 T when compared to recordings at 0 T. Nevertheless, it seems that the increased amplitudes of the ERPs are due to the effect of the ultra-high field on the EEG recording system rather than alteration in the intrinsic processes that generate the electrophysiological responses.

  12. Magnetic optics for proton radiography

    SciTech Connect

    Mottershead, C.T.; Zumbro, J.D.

    1997-10-01

    High energy protons of 10 to 50 GeV can be used to radiograph dense objects. Because the transmitted beam particles undergo multiple coulomb scattering (MCS) in the object, a magnetic lens system is used to focus the particles exiting each point of the object onto a distant image plane. Without the lens, the MCS would seriously blur the radiographic image. Correlations can be introduced in the illuminating beam to cancel a major part of the chromatic and geometric aberrations in the lens, while providing locations inside the lens where the rays are sorted by MCS angle. This allows the introduction of angle cut apertures to aid material identification. The requirement for a matched multistage lens system with successively smaller angle-cut apertures leads to the use of minus-identity ({minus}I) lenses, in which the angle sorting is in the longitudinal mid plane of the lens, and the exit beam correlations are the same as the input correlations. A single stage {minus}I lens has been successfully tested at Brookhaven with 10-GeV protons and another is being used in dynamic experiments with 0.8-GeV protons at Los Alamos. The resolution achievable at higher energies is briefly surveyed.

  13. Suppressive effects of a proton beam on tumor growth and lung metastasis through the inhibition of metastatic gene expression in 4T1 orthotopic breast cancer model.

    PubMed

    Kwon, Yun-Suk; Lee, Kyu-Shik; Chun, So-Young; Jang, Tae Jung; Nam, Kyung-Soo

    2016-07-01

    A proton beam is a next generation tool to treat intractable cancer. Although the therapeutic effects of a proton beam are well known, the effect on tumor metastasis is not fully described. Here, we investigated the effects of a proton beam on metastasis in highly invasive 4T1 murine breast cancer cells and their orthotopic breast cancer model. Cells were irradiated with 2, 4, 8 or 16 Gy proton beam, and changes in cell proliferation, survival, and migration were observed by MTT, colony forming and wound healing assays. 4T1 breast cancer cell-implanted BALB/c mice were established and the animals were randomly divided into 4 groups when tumor size reached 200 mm3. Breast tumors were selectively irradiated with 10, 20 or 30 Gy proton beam. Breast tumor sizes were measured twice a week, and breast tumor and lung tissues were pathologically observed. Metastasis-regulating gene expression was assessed with quantitative RT-PCR. A proton beam dose-dependently decreased cell proliferation, survival and migration in 4T1 murine breast cancer cells. Also, growth of breast tumors in the 4T1 orthotopic breast cancer model was significantly suppressed by proton beam irradiation without significant change of body weight. Furthermore, fewer tumor nodules metastasized from breast tumor into lung in mice irradiated with 30 Gy proton beam, but not with 10 and 20 Gy, than in control. We observed correspondingly lower expression levels of urokinase plasminogen activator (uPA), uPA receptor, cyclooxygenase (COX)-2, and vascular endothelial growth factor (VEGF), which are important factors in cancer metastasis, in breast tumor irradiated with 30 Gy proton beam. Proton beam irradiation did not affect expressions of matrix metalloproteinase (MMP)-9 and MMP-2. Taken together, the data suggest that, although proton beam therapy is an effective tool for breast cancer treatment, a suitable dose is necessary to prevent metastasis-linked relapse and poor prognosis.

  14. Methods for pulse artefact reduction: experiences with EEG data recorded at 9.4 T static magnetic field.

    PubMed

    Arrubla, Jorge; Neuner, Irene; Dammers, Jürgen; Breuer, Lukas; Warbrick, Tracy; Hahn, David; Poole, Michael S; Boers, Frank; Shah, N Jon

    2014-07-30

    The feasibility of recording electroencephalography (EEG) at ultra-high static magnetic fields up to 9.4 T was recently demonstrated and is expected to be incorporated into functional magnetic resonance imaging (fMRI) studies at 9.4 T. Correction of the pulse artefact (PA) is a significant challenge since its amplitude is proportional to the strength of the magnetic field in which EEG is recorded. We conducted a study in which different PA correction methods were applied to EEG data recorded inside a 9.4 T scanner in order to retrieve visual P100 and auditory P300 evoked potentials. We explored different PA reduction methods, including the optimal basis set (OBS) method as well as objective and subjective component rejection using independent component analysis (ICA). ICA followed by objective rejection of components is optimal for retrieving visual P100 and auditory P300 from EEG data recorded inside the scanner. Previous studies suggest that OBS or OBS followed by ICA are optimal for retrieving evoked potentials at 3T. In our EEG data recorded at 9.4 T OBS performed alone was not fully optimal for the identification of evoked potentials. OBS followed by ICA was partially effective. In this study ICA has been shown to be an important tool for correcting the PA in EEG data recorded at 9.4 T, particularly when automated rejection of components is performed. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Chemical Principles Revisited. Proton Magnetic Resonance Spectroscopy.

    ERIC Educational Resources Information Center

    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)

  16. Chemical Principles Revisited. Proton Magnetic Resonance Spectroscopy.

    ERIC Educational Resources Information Center

    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)

  17. Magnetic resonance imaging at 9.4 T as a tool for studying neural anatomy in non-vertebrates.

    PubMed

    Brinkley, Catherine K; Kolodny, Nancy H; Kohler, Susan J; Sandeman, David C; Beltz, Barbara S

    2005-07-15

    This report describes magnetic resonance imaging (MRI) methods we have developed at 9.4 T for observing internal organs and the nervous system of an invertebrate organism, the crayfish, Cherax destructor. We have compared results acquired using two different pulse sequences, and have tested manganese (Mn(2+)) as an agent to enhance contrast of neural tissues in this organism. These techniques serve as a foundation for further development of functional MRI and neural tract-tracing methods in non-vertebrate systems.

  18. Polywater: proton nuclear magnetic resonance spectrum.

    PubMed

    Page, T F; Jakobsen, R J; Lippincott, E R

    1970-01-02

    In the presence of water, the resonance of the strongly hydrogenbonded protons characteristic of polywater appears at 5 parts per million lower applied magnetic field than water. Polywater made by a new method confirms the infrared spectrum reported originally.

  19. Proton magnetic resonance spectrum of polywater.

    PubMed

    Petsko, G A

    1970-01-09

    With the aid of a time average computer, the proton magnetic resonance spectrum of anomalous water (polywater) is obtained. The spectrum conisists of a single broad resonance shifted approximately 300 hertz downfield from the resonance of ordinary water.

  20. Nuclear magnetic resonance studies reveal stabilization of parallel G-quadruplex DNA [d(T2G4T)]4 upon binding to protoberberine alkaloid coralyne.

    PubMed

    Padmapriya, Kumar; Barthwal, Ritu

    2016-10-15

    Stabilization of G-quadruplex DNA structures in human telomeric and proto-oncogenic promoter regions upon ligand binding has evolved as a viable anti-cancer strategy. We have studied interaction of coralyne, a human telomerase inhibiting protoberberine alkaloid, with parallel stranded tetrameric G-quadruplex DNA [d(T2G4T)]4 using Circular Dichroism (CD) and nuclear magnetic resonance (NMR) spectroscopy. Appearance of induced CD band and the Diffusion Ordered NMR Spectroscopy (DOSY) experiments confirm the formation of well defined coralyne-DNA complex. (1)H and (31)P NMR studies reveal that coralyne specifically recognizes T2pG3 and G6pT7 steps in DNA. Guanine imino protons indicate that coralyne binding induces thermal stabilization of the G-quadruplex DNA by >20°C. The observed specific changes and thermal stabilization of DNA upon binding may be attributed to inhibition of telomerase by coralyne.

  1. Design of a conduction-cooled 9.4 T REBCO magnet for whole-body MRI systems

    NASA Astrophysics Data System (ADS)

    Miyazaki, Hiroshi; Iwai, Sadanori; Otani, Yasumi; Takahashi, Masahiko; Tosaka, Taizo; Tasaki, Kenji; Nomura, Shunji; Kurusu, Tsutomu; Ueda, Hiroshi; Noguchi, So; Ishiyama, Atsushi; Urayama, Shinichi; Fukuyama, Hidenao

    2016-10-01

    A project on the development of REBa2Cu3O7-δ (REBCO) magnets for ultra-high-field magnetic resonance imaging (MRI) was started in 2013. Since REBCO-coated conductors feature high mechanical strength under tensile stress and high critical current density, use of REBCO coils would allow superconducting magnets to be made smaller and lighter than conventional ones. In addition, a conduction-cooled superconducting magnet is simpler to use than one cooled by a liquid helium bath because the operation and maintenance of the cryogenic system become simpler, without the need to handle cryogenic fluid. Superconducting magnets for MRI require homogeneous, stable magnetic fields. The homogeneity of the magnetic field is highly dependent on the coil shape and position. Moreover, in REBCO magnets, the screening-current-induced magnetic field, which changes the magnetic field distribution of the magnet, is one of the critical issues. In order to evaluate the magnetic field homogeneity and the screening-current-induced magnetic field, a 1 T model magnet and some test coils were fabricated. From an evaluation of the 1 T model magnet, it was found that the main reason for magnetic field inhomogeneity was the tolerances in the z-axis positions of the coils, and therefore, it is important to control the gap between the single pancakes. In addition, we have already demonstrated the generation of an 8.27 T central magnetic field at 10 K with a small test coil. The screening-current-induced magnetic field was 0.43 T and was predictable by using an electromagnetic field simulation program. These results were reflected in the design of a conduction-cooled 9.4 T REBCO magnet for whole-body MRI systems. The magnet was composed of six main coils and two active shield coils. The total conductor length was 581 km, and the stored energy was 293 kJ. The field inhomogeneity was 24 ppm peak to peak and 3 ppm volume-root-mean-square (VRMS) for a 500 mm diameter spherical volume (DSV). The axial

  2. Proton magnetic resonance spectroscopy in multiple sclerosis

    SciTech Connect

    Wolinsky, J.S.; Narayana, P.A.; Fenstermacher, M.J. )

    1990-11-01

    Regional in vivo proton magnetic resonance spectroscopy provides quantitative data on selected chemical constituents of brain. We imaged 16 volunteers with clinically definite multiple sclerosis on a 1.5 tesla magnetic resonance scanner to define plaque-containing volumes of interest, and obtained localized water-suppressed proton spectra using a stimulated echo sequence. Twenty-five of 40 plaque-containing regions provided spectra of adequate quality. Of these, 8 spectra from 6 subjects were consistent with the presence of cholesterol or fatty acids; the remainder were similar to those obtained from white matter of normal volunteers. This early experience with regional proton spectroscopy suggests that individual plaques are distinct. These differences likely reflect dynamic stages of the evolution of the demyelinative process not previously accessible to in vivo investigation.

  3. Imaging Intelligence with Proton Magnetic Resonance Spectroscopy

    ERIC Educational Resources Information Center

    Jung, Rex E.; Gasparovic, Charles; Chavez, Robert S.; Caprihan, Arvind; Barrow, Ranee; Yeo, Ronald A.

    2009-01-01

    Proton magnetic resonance spectroscopy ([to the first power]H-MRS) is a technique for the assay of brain neurochemistry "in vivo." N-acetylaspartate (NAA), the most prominent metabolite visible within the [to the first power]H-MRS spectrum, is found primarily within neurons. The current study was designed to further elucidate NAA-cognition…

  4. Imaging Intelligence with Proton Magnetic Resonance Spectroscopy

    ERIC Educational Resources Information Center

    Jung, Rex E.; Gasparovic, Charles; Chavez, Robert S.; Caprihan, Arvind; Barrow, Ranee; Yeo, Ronald A.

    2009-01-01

    Proton magnetic resonance spectroscopy ([to the first power]H-MRS) is a technique for the assay of brain neurochemistry "in vivo." N-acetylaspartate (NAA), the most prominent metabolite visible within the [to the first power]H-MRS spectrum, is found primarily within neurons. The current study was designed to further elucidate NAA-cognition…

  5. Proton acceleration from magnetized overdense plasmas

    NASA Astrophysics Data System (ADS)

    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.

  6. Protonation of deoxycytidine residues in dC4 tetraloops: UV spectrophotometric study of dC10 and d(A14C4T14).

    PubMed

    Raukas, E; Kooli, K

    2003-06-01

    It is shown that component analysis could be applied to study the UV difference spectra of cytidine oligomers and hairpin oligonucleotides with cytidines in the loop region in order to account for the melting and titration results in terms of cytidine stacking and protonation. Upon acid titration, the dC(10) oligomer undergoes cooperative conformational transition at pH 6.3 accompanied by protonation and formation of the i-structure with half of the residues protonated. The stability of the hemiprotonated structure increases with decreasing pH, the i-structure persisting still in the region of pH4)T(14)). It is shown that upon titration, the 50% level of protonation of the deoxycytidine tetraloop is attained at pH 5.0. Simultaneously, the stacking interactions of cytidine residues reach the maximum at this pH with two residues stacked, and thereafter decline again. Only marginal stabilization of the oligomer hairpin (DeltaT(m)=1.5 degrees C) is found to accompany the formation of this single hemiprotonated dC.dC(+) base pair. We propose that at pH 5 the cytidines of the dC(4) loop form a hemiprotonated dC.dC(+) pair stacked with the last dA.dT base pair of the hairpin stem.

  7. Low-dose γ-rays modify CD4(+) T cell signalling response to simulated solar particle event protons in a mouse model.

    PubMed

    Rizvi, Asma; Pecaut, Michael J; Slater, James M; Subramaniam, Shruti; Gridley, Daila S

    2011-01-01

    Astronauts on missions are exposed to low-dose/low-dose-rate (LDR) radiation and could receive high doses during solar particle events (SPE). This study investigated T cell function in response to LDR radiation and simulated SPE (sSPE) protons, alone and in combination. C57BL/6 mice received LDR γ-radiation (⁵⁷Co) to a total dose of 0.01 Gray (Gy) at 0.179 mGy/h, either with or without subsequent exposure to 1.7 Gy sSPE protons delivered over 36 h. Mice were euthanised on days 4 and 21 post-exposure. T cells with cluster of differentiation 4 (CD4(+)) were negatively isolated from spleens and activated with anti-CD3 antibody. Cells and supernatants were evaluated for survival/signalling proteins and cytokines. The most striking effects were noted on day 21. In the survival pathway, nuclear factor-kappaB (NF-κB; total and active forms) and p38 mitogen activated protein kinase (p38MAPK; total) were significantly increased and cJun N-terminal kinase (JNK; total and active) was decreased when mice were primed with LDR γ-rays prior to sSPE exposure (P < 0.001). Evaluation of the T cell antigen receptor (TCR) signalling pathway revealed that LDR γ-ray exposure normalised the high sSPE proton-induced level of lymphocyte specific protein tyrosine kinase (Lck; total and active) on day 21 (P < 0.001 for sSPE vs. LDR + sSPE), while radiation had no effect on active zeta-chain-associated protein kinase 70 (Zap-70). There was increased production of interleukin-2 (IL-2) and IL-4 and decreased transforming growth factor-β1 in the LDR + sSPE group compared to the sSPE group. The data demonstrate, for the first time, that protracted exposure to LDR γ-rays can significantly modify the effects of sSPE protons on critical survival/signalling proteins and immunomodulatory cytokines produced by CD4(+) T cells.

  8. Magnetic monopole catalysis of proton decay

    SciTech Connect

    Marciano, W.J.; Salvino, D.

    1986-09-01

    Catalysis of proton decay by GUT magnetic monopoles (the Rubakov-Callan effect) is discussed. Combining a short-distance cross section calculation by Bernreuther and Craigie with the long-distance velocity dependent distortion factors of Arafune and Fukugita, catalysis rate predictions which can be compared with experiment are obtained. At present, hydrogen rich detectors such as water (H/sub 2/O) and methane (CH/sub 4/) appear to be particularly well suited for observing catalysis by very slow monopoles. 17 refs., 1 fig.

  9. Strange magnetism and the anapole structure of the proton.

    SciTech Connect

    Hasty, R.; Hawthorne-Allen, A. M.; Averett, T.; Barkhuff, D.; Beck, D. H.; Mueller, B.; SAMPLE Collaboration; Physics; Univ. of Illinois; Virginia Polytechnic Inst. and State Univ.; Coll. of William and Mary; Lab. for Nuclear Science and Department of Physics

    2000-12-15

    The violation of mirror symmetry in the weak force provides a powerful tool to study the internal structure of the proton. Experimental results have been obtained that address the role of strange quarks in generating nuclear magnetism. The measurement reported here provides an unambiguous constraint on strange quark contributions to the proton's magnetic moment through the electron-proton weak interaction. We also report evidence for the existence of a parity-violating electromagnetic effect known as the anapole moment of the proton. The proton's anapole moment is not yet well understood theoretically, but it could have important implications for precision weak interaction studies in atomic systems such as cesium.

  10. Time-frequency analysis of resting state and evoked EEG data recorded at higher magnetic fields up to 9.4 T.

    PubMed

    Abbasi, Omid; Dammers, Jürgen; Arrubla, Jorge; Warbrick, Tracy; Butz, Markus; Neuner, Irene; Shah, N Jon

    2015-11-30

    Combining both high temporal and spatial resolution by means of simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) is of relevance to neuroscientists. This combination, however, leads to a distortion of the EEG signal by the so-called cardio-ballistic artefacts. The aim of the present study was developing an approach to restore meaningful physiological EEG data from recordings at different magnetic fields. The distortions introduced by the magnetic field were corrected using a combination of concepts from independent component analysis (ICA) and mutual information (MI). Thus, the components were classified as either related to the cardio-ballistic artefacts or to the signals of interest. EEG data from two experimental paradigms recorded at different magnetic field strengths up to 9.4 T were analyzed: (i) spontaneous activity using an eyes-open/eyes-closed alternation, and (ii) responses to auditory stimuli, i.e. auditory evoked potentials. Even at ultra-high magnetic fields up to 9.4 T the proposed artefact rejection approach restored the physiological time-frequency information contained in the signal of interest and the data were suitable for subsequent analyses. Blind source separation (BSS) has been used to retrieve information from EEG data recorded inside the MR scanner in previous studies. After applying the presented method on EEG data recorded at 4 T, 7 T, and 9.4 T, we could retrieve more information than from data cleaned with the BSS method. The present work demonstrates that EEG data recorded at ultra-high magnetic fields can be used for studying neuroscientific research question related to oscillatory activity. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Soft x-ray magnetic circular dichroism study of valence and spin states in FeT2O4 (T = V, Cr) spinel oxides

    NASA Astrophysics Data System (ADS)

    Kang, J.-S.; Hwang, Jihoon; Kim, D. H.; Lee, Eunsook; Kim, W. C.; Kim, C. S.; Lee, Han-Koo; Kim, J.-Y.; Han, S. W.; Hong, S. C.; Kim, Bongjae; Min, B. I.

    2013-05-01

    Electronic structures of spinel oxides FeT2O4 (T = V, Cr) have been investigated by employing soft x-ray magnetic circular dichroism (XMCD) and soft x-ray absorption spectroscopy (XAS). XAS reveals that Cr and V ions are trivalent, and that Fe ions are nearly divalent in FeT2O4 (T = V, Cr). Finite XMCD signals are observed in FeV2O4 at T = 80 K, while they are very weak in FeCr2O4. XMCD shows that Fe spins are antiparallel to V and Cr spins, with the V and Cr spins being canted from Fe spins, which suggests a Yafet-Kittel type triangular spin configuration in FeT2O4 (T = V, Cr).

  12. Porphyrin protonation studied by magnetic circular dichroism.

    PubMed

    Štěpánek, Petr; Andrushchenko, Valery; Ruud, Kenneth; Bouř, Petr

    2012-01-12

    Magnetic circular dichroism (MCD) spectroscopy provides valuable information about electronic excited states in molecules. The interpretation of spectra is however difficult, often requiring additional theoretical calculations to rationalize the observed signal. Recent developments in time-dependent density functional theory (TDDFT) bring hope that the applicability of MCD spectroscopy for chemical problems may be significantly extended. In this study, two modern analytical TDDFT implementations are compared and used to understand experimental MCD spectra of a model porphyrin system upon protonation. Changes in porphyrin geometry and electronic structure are related to MCD intensities by comparing the spectra of 5,10,15,20-tetraphenyl-21H,23H-porphyrintetrasulfonic acid (TPPS) measured at different pH values with the TDDFT calculations. Although the theoretical results slightly depended on the chosen exchange-correlation functional, the computations provided MCD curves that could well rationalize the experimental data. The protonation of the porphyrin core causes marked changes in the MCD spectrum, whereas the role of the substituents is limited. Also, different conformations of the porphyrin substituents cause relatively minor changes of the MCD pattern, mostly in the Soret region, where the porphine and phenyl electronic transitions start to mix. The solvent environment simulated by the dielectric model caused a shift (~20 nm) of the absorption bands but only minor variations in the absorption and MCD spectral shapes. The study thus demonstrates that the recently available first-principles interpretations of MCD spectra significantly enhance the applicability of the technique for molecular structural studies.

  13. Enhanced proton acceleration in an applied longitudinal magnetic field

    NASA Astrophysics Data System (ADS)

    Arefiev, A.; Toncian, T.; Fiksel, G.

    2016-10-01

    Using two-dimensional particle-in-cell simulations, we examine how an externally applied strong magnetic field 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-level 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 possibility of improving characteristics of laser-driven proton beams using such fields is a strong motivation for further development of laser-driven magnetic field capabilities.

  14. Proton magnetometers for measurement of the Earth's magnetic field

    NASA Astrophysics Data System (ADS)

    Hrvoic, Ivan

    1990-02-01

    Proton magnetometers are an excellent example of nuclear physics phenomena brought into and exploited in our normal, macroscopic world. Relatively easy and efficient manipulation of nuclear precession phenomena is possible and very often done even without proper understanding of the underlying physics. Overhauser effect is based on the same nuclear physics phenomena, although marginally more complex and again macroscopically engineered to improve on simple proton precession effects in order to achieve much better precession signals from smaller sensors and using less power. Since the polarization of protons (generation of proton precession signal) does not require strong static magnetic fields but uses strong radio frequency magnetic field transparent to protons, measurements can be done concurrently with it. Furthermore, in the ultimate triumph of the method, one can produce a stationary, nondecaying proton precession signal, in vague similarity to alkali vapor magnetometers using simple feedback techniques. The underlying physics of the two methods are examined.

  15. Enhanced proton acceleration in an applied longitudinal magnetic field

    NASA Astrophysics Data System (ADS)

    Toncian, Toma; Arefiev, Alexey; Fiksel, Gennady

    2016-10-01

    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 characteristics of laser-driven proton beams would be critical for a number of applications. The work was supported by U.S. Department of Energy - National Nuclear Security Administration Cooperative Agreement No. DE-NA0002008. HPC resources were provided by the Texas Advanced Computing Center at The University of Texas.

  16. Effects of magnetic induction hyperthermia and radiotherapy alone or combined on a murine 4T1 metastatic breast cancer model.

    PubMed

    Wang, Hui; Li, Xiao; Xi, Xuping; Hu, Bingqiang; Zhao, Lingyun; Liao, Yuping; Tang, Jintian

    2011-01-01

    The purpose of this study was to explore the effects of MIH and radiotherapy alone or combined on metastatic breast cancer and the underlying mechanisms. A murine 4T1 metastatic breast cancer model was established and randomly assigned into four treatment groups: C (control), R (radiotherapy), MIH, and MIH+R. Tumour volume, lung metastasis, the expression of Bax and MMP-9, T cell subsets, serum cytokine levels, and mouse survival were evaluated. Group MIH + R showed significantly reduced tumour volume, lung metastasis, improved survival and increased Bax expression compared to group R or MIH (P<0.05). MMP-9 expression in the primary tumour tissue was significantly increased in group R compared to the other groups (P<0.05), which could be brought down by combined MIH treatment. Group MIH +R showed significantly higher CD4(+) T cell percentage as well as CD4(+)/CD8(+) cell ratio than group R (P<0.05). Group MIH+R showed significantly higher serum levels of TNF-α, IFN-γ and IL-2 than group R (P<0.05). MIH not only promotes the tumour-cell killing effect of radiotherapy through Bax-mediated cell death, but also improves cellular immunity in mice under radiotherapy and decreases the potential of radiotherapy to enhance MMP-9 expression, which leads to significant improvement in lung metastasis and overall survival of mice under combined treatment of MIH and R. This study is the first to have explored the effect of combined hyperthermia and radiotherapy on tumour metastasis and the underlying mechanisms. It provides insights into the application of MIH as an adjuvant to radiotherapy for metastatic breast cancer.

  17. Simultaneous EEG-fMRI acquisition at low, high and ultra-high magnetic fields up to 9.4 T: perspectives and challenges.

    PubMed

    Neuner, Irene; Arrubla, Jorge; Felder, Jörg; Shah, N Jon

    2014-11-15

    In this perspectives article we highlight the advantages of simultaneous acquisition of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). As MRI moves towards using ultra-high magnetic fields in the quest for increased signal-to-noise, the question arises whether combined EEG-fMRI measurements are feasible at magnetic fields of 7 T and higher. We describe the challenges of MRI-EEG at 1.5, 3, 7 and 9.4 T and review the proposed solutions. In an outlook, we discuss further developments such as simultaneous trimodal imaging using MR, positron emission tomography (PET) and EEG under the same physiological conditions in the same subject. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Helical Dipole Magnets for Polarized Protons in RHIC

    NASA Astrophysics Data System (ADS)

    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.

  19. Effects of magnetic fields of up to 9.4 T on resolution and contrast of PET images as measured with an MR-BrainPET.

    PubMed

    Shah, N Jon; Herzog, Hans; Weirich, Christoph; Tellmann, Lutz; Kaffanke, Joachim; Caldeira, Liliana; Kops, Elena Rota; Qaim, Syed M; Coenen, Heinz H; Iida, Hidehiro

    2014-01-01

    Simultaneous, hybrid MR-PET is expected to improve PET image resolution in the plane perpendicular to the static magnetic field of the scanner. Previous papers have reported this either by simulation or experiment with simple sources and detector arrangements. Here, we extend those studies using a realistic brain phantom in a recently installed MR-PET system comprising a 9.4 T MRI-scanner and an APD-based BrainPET insert in the magnet bore. Point and line sources and a 3D brain phantom were filled with 18F (low-energy positron emitter), 68Ga (medium energy positron emitter) or 120I, a non-standard positron emitter (high positron energies of up to 4.6 MeV). Using the BrainPET insert, emission scans of the phantoms were recorded at different positions inside and outside the magnet bore such that the magnetic field was 0 T, 3 T, 7 T or 9.4 T. Brain phantom images, with the 'grey matter' compartment filled with 18F, showed no obvious resolution improvement with increasing field. This is confirmed by practically unchanged transaxial FWHM and 'grey/white matter' ratio values between at 0T and 9.4T. Field-dependent improvements in the resolution and contrast of transaxial PET images were clearly evident when the brain phantom was filled with 68Ga or 120I. The grey/white matter ratio increased by 7.3% and 16.3%, respectively. The greater reduction of the FWTM compared to FWHM in 68Ga or 120I line-spread images was in agreement with the improved contrast of 68Ga or 120I images. Notwithstanding elongations seen in the z-direction of 68Ga or 120I point source images acquired in foam, brain phantom images show no comparable extension. Our experimental study confirms that integrated MR-PET delivers improved PET image resolution and contrast for medium- and high-energy positron emitters even though the positron range is reduced only in directions perpendicular to the magnetic field.

  20. Effects of Magnetic Fields of up to 9.4 T on Resolution and Contrast of PET Images as Measured with an MR-BrainPET

    PubMed Central

    Shah, N. Jon; Herzog, Hans; Weirich, Christoph; Tellmann, Lutz; Kaffanke, Joachim; Caldeira, Liliana; Kops, Elena Rota; Qaim, Syed M.; Coenen, Heinz H.; Iida, Hidehiro

    2014-01-01

    Simultaneous, hybrid MR-PET is expected to improve PET image resolution in the plane perpendicular to the static magnetic field of the scanner. Previous papers have reported this either by simulation or experiment with simple sources and detector arrangements. Here, we extend those studies using a realistic brain phantom in a recently installed MR-PET system comprising a 9.4 T MRI-scanner and an APD-based BrainPET insert in the magnet bore. Point and line sources and a 3D brain phantom were filled with 18F (low-energy positron emitter), 68Ga (medium energy positron emitter) or 120I, a non-standard positron emitter (high positron energies of up to 4.6 MeV). Using the BrainPET insert, emission scans of the phantoms were recorded at different positions inside and outside the magnet bore such that the magnetic field was 0 T, 3 T, 7 T or 9.4 T. Brain phantom images, with the ‘grey matter’ compartment filled with 18F, showed no obvious resolution improvement with increasing field. This is confirmed by practically unchanged transaxial FWHM and ‘grey/white matter’ ratio values between at 0T and 9.4T. Field-dependent improvements in the resolution and contrast of transaxial PET images were clearly evident when the brain phantom was filled with 68Ga or 120I. The grey/white matter ratio increased by 7.3% and 16.3%, respectively. The greater reduction of the FWTM compared to FWHM in 68Ga or 120I line-spread images was in agreement with the improved contrast of 68Ga or 120I images. Notwithstanding elongations seen in the z-direction of 68Ga or 120I point source images acquired in foam, brain phantom images show no comparable extension. Our experimental study confirms that integrated MR-PET delivers improved PET image resolution and contrast for medium- and high-energy positron emitters even though the positron range is reduced only in directions perpendicular to the magnetic field. PMID:24755872

  1. Helical dipole magnets for polarized protons in RHIC

    SciTech Connect

    Syphers, M.; Courant, E.; Fischer, W.

    1997-07-01

    Superconducting helical dipole magnets will be used in the Brookhaven Relativistic Heavy Ion Collider (RHIC) to maintain polarization of proton beams and to perform localized spin rotations at the two major experimental detector regions. Requirements for the helical dipole system are discussed, and magnet prototype work is reported.

  2. Antibody-free magnetic cell sorting of genetically modified primary human CD4+ T cells by one-step streptavidin affinity purification.

    PubMed

    Matheson, Nicholas J; Peden, Andrew A; Lehner, Paul J

    2014-01-01

    Existing methods for phenotypic selection of genetically modified mammalian cells suffer disadvantages of time, cost and scalability and, where antibodies are used to bind exogenous cell surface markers for magnetic selection, typically yield cells coated with antibody-antigen complexes and beads. To overcome these limitations we have developed a method termed Antibody-Free Magnetic Cell Sorting in which the 38 amino acid Streptavidin Binding Peptide (SBP) is displayed at the cell surface by the truncated Low Affinity Nerve Growth Receptor (LNGFRF) and used as an affinity tag for one-step selection with streptavidin-conjugated magnetic beads. Cells are released through competition with the naturally occurring vitamin biotin, free of either beads or antibody-antigen complexes and ready for culture or use in downstream applications. Antibody-Free Magnetic Cell Sorting is a rapid, cost-effective, scalable method of magnetic selection applicable to either viral transduction or transient transfection of cell lines or primary cells. We have optimised the system for enrichment of primary human CD4+ T cells expressing shRNAs and exogenous genes of interest to purities of >99%, and used it to isolate cells following Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 genome editing.

  3. Pion Production from Proton Synchrotron Radiation in Strong Magnetic Fields

    NASA Astrophysics Data System (ADS)

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

    We study pion production by proton synchrotron radiation in the presence of a strong magnetic field. In this study we find that the decay width satisfies a robust scaling relation. 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. Then, we present the resultant pion intensity and angular distributions for realistic magnetic field strengths.

  4. Proton magnetic relaxation dispersion in aqueous biopolymer systems

    NASA Astrophysics Data System (ADS)

    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.

  5. The Magnetic Moments of the Proton and the Antiproton

    NASA Astrophysics Data System (ADS)

    Ulmer, Stefan; Smorra, Christian

    A comparison of the magnetic moments of the proton and the antiproton provides a sensitive test of matter-antimatter symmetry. While the magnetic moment of the proton is known with a relative precision of 10^{-8}, that of the antiproton is only known with moderate accuracy. Important progress towards a high-precision measurement of the particle's magnetic moment was reported in 2011 by a group at Mainz when spin transitions of a single proton stored in a cryogenic Penning trap were observed. To resolve the single-proton spin flips, the so-called 'continuous Stern-Gerlach effect' was utilized. Using this technique, the proton magnetic moment was measured by two groups at Mainz and Harvard with relative precisions of 8.9× 10^{-6} and 2.5× 10^{-6}, respectively. Currently, two collaborations at the CERN antiproton decelerator (AD)—a part of ATRAP and BASE—are pushing their efforts to apply the methods developed for the proton to measure the magnetic moment of the antiproton. Very recently, DiSciacca et al. reported on a measurement of the antiproton's magnetic moment with a relative precision of 4.4 ppm, which is a improvement of the formerly best value by about a factor of 680. Using the so-called double Penning trap technique, both collaborations aim for a precision measurement at the level of at least 10^{-9} in future experiments, which would provide a highly sensitive test of the CPT symmetry using baryons.

  6. Magnetic resonance spectroscopy study of the glutamatergic system in adolescent males with high-functioning autistic disorder: a pilot study at 4T.

    PubMed

    Joshi, Gagan; Biederman, Joseph; Wozniak, Janet; Goldin, Rachel L; Crowley, Dave; Furtak, Stephannie; Lukas, Scott E; Gönenç, Atilla

    2013-08-01

    The pilot study aimed at examining the neural glutamatergic activity in autism. Seven adolescent males (mean age: 14 ± 1.8; age range: 12-17 years) with intact intellectual capacity (mean IQ: 108 ± 14.26; IQ range: 85-127) suffering from autistic disorder and an equal number of age- and sex-matched healthy controls underwent a two-dimensional magnetic resonance spectroscopy scan at 4T. Results indicated significantly high glutamate (Glu) levels in the anterior cingulate cortex of autistic disorder versus control subjects (paired t test p = 0.01) and a trend for lower Glu in the right medial temporal lobe, which was not statistically different between the groups (paired t test p = 0.06). These preliminary findings support the glutamatergic dysregulation hypothesis in autism and need to be replicated in a larger sample.

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

    PubMed

    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. © The Author(s) 2014.

  8. On the Importance of Exchangeable NH Protons in Creatine for the Magnetic Coupling of Creatine Methyl Protons in Skeletal Muscle

    NASA Astrophysics Data System (ADS)

    Kruiskamp, M. J.; Nicolay, K.

    2001-03-01

    The methyl protons of creatine in skeletal muscle exhibit a strong off-resonance magnetization transfer effect. The mechanism of this process is unknown. We previously hypothesized that the exchangeable amide/amino protons of creatine might be involved. To test this the characteristics of the creatine magnetization transfer effect were investigated in excised rat hindleg skeletal muscle that was equilibrated in either H2O or D2O solutions containing creatine. The efficiency of off-resonance magnetization transfer to the protons of mobile creatine in excised muscle was similar to that previously reported in intact muscle in vivo. Equilibrating the isolated muscle in D2O solution had no effect on the magnetic coupling to the immobile protons. It is concluded that exchangeable protons play a negligible role in the magnetic coupling of creatine methyl protons in muscle.

  9. Proton magnetic relaxation and internal rotations in tetramethylammonium cadmium chloride

    NASA Technical Reports Server (NTRS)

    Tsang, T.; Utton, D. B.

    1976-01-01

    Nuclear magnetic resonance (NMR) and relaxation studies of the proton spin-lattice relaxation time (PSLRT) and proton second moment (PSM) are reported. Tetramethylammonium cadmium chloride (TMCC) was selected as a diamagnetic member of the isomorphic series, and hence proton data relate directly to the motion of the tetramethylammonium ion in the absence of paramagnetic ions. In the model adopted, the correlation time for hindered motion of one of the methyl groups differs from that of the other three groups in the low-temperature phase below 104 K. PSLRT and PSM values agree closely with experimental data with this model. Crystallographic phase transitions in TMCC occur at 104 K and 119 K according to the PSLRT measurements. Dipolar interactions between adjacent protons account for the PSLR rates below 104 K.

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

    NASA Technical Reports Server (NTRS)

    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.

  11. Tracking Efficiency And Charge Sharing of 3D Silicon Sensors at Different Angles in a 1.4T Magnetic Field

    SciTech Connect

    Gjersdal, H.; Bolle, E.; Borri, M.; Da Via, C.; Dorholt, O.; Fazio, S.; Grenier, P.; Grinstein, S. Hansson, P.; Hasi, J.; Hugging, F.; Jackson, P.; Kenney, C.; Kocian, M.; La Rosa, A.; Mastroberardino, A.; Nordahl, P.; Rivero, F.; Rohne, O.; Sandaker, H.; Sjobaek, K.; /Oslo U. /Prague, Tech. U. /SLAC /Bonn U. /SUNY, Stony Brook /Bonn U. /SLAC

    2012-05-07

    A 3D silicon sensor fabricated at Stanford with electrodes penetrating throughout the entire silicon wafer and with active edges was tested in a 1.4 T magnetic field with a 180 GeV/c pion beam at the CERN SPS in May 2009. The device under test was bump-bonded to the ATLAS pixel FE-I3 readout electronics chip. Three readout electrodes were used to cover the 400 {micro}m long pixel side, this resulting in a p-n inter-electrode distance of {approx} 71 {micro}m. Its behavior was confronted with a planar sensor of the type presently installed in the ATLAS inner tracker. Time over threshold, charge sharing and tracking efficiency data were collected at zero and 15{sup o} angles with and without magnetic field. The latest is the angular configuration expected for the modules of the Insertable B-Layer (IBL) currently under study for the LHC phase 1 upgrade expected in 2014.

  12. The magnetic moments of the proton and the antiproton

    NASA Astrophysics Data System (ADS)

    Ulmer, S.; Mooser, A.; 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.

    2014-04-01

    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 μp 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 μp. The techniques required for the proton can be directly applied to measure the antiproton magnetic moment μp. An improvement in precision of μp 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 Baryon Antibaryon Symmetry Experiment (BASE) at the antiproton decelerator (AD) of CERN.

  13. Magnetic Field Distribution and Signal Decay in Functional MRI in Very High Fields (up to 9.4 T) Using Monte Carlo Diffusion Modeling

    PubMed Central

    Mueller-Bierl, Bernd Michael; Uludag, Kamil; Pereira, Philippe L.; Schick, Fritz

    2007-01-01

    Extravascular signal decay rate R2 or R2∗ as a function of blood oxygenation, geometry, and field strength was calculated using a Monte Carlo (MC) algorithm for a wider parameter range than hitherto by others. The relaxation rates of gradient-recalled-echo (GRE) and Hahn-spin-echo (HSE) imaging in the presence of blood vessels (ranging from capillaries to veins) have been computed for a wide range of field strengths up to 9.4T and 50% blood deoxygenation. The maximum HSE decay was found to be shifted to lower radii in higher compared to lower field strengths. For GRE, however, the relaxation rate was greatest for large vessels at any field strength. In addition, assessments of computational reliability have been carried out by investigating the influence of the time step, the Monte Carlo step procedure, boundary conditions, the number of angles between the vessel and the exterior field B0, the influence of neighboring vessels having the same orientation as the central vessel, and the number of proton spins. The results were compared with those obtained from a field distribution of the vessel computed by an analytic formula describing the field distribution of an ideal object (an infinitely long cylinder). It was found that the time step is not critical for values equal to or lower than 200 microseconds. The choice of the MC step procedure (three-dimensional Gaussian diffusion, constant one- or three-dimensional diffusion step) also failed to influence the results significantly; in contrast, the free boundary conditions, as well as taking too few angles into account, did introduce errors. Next neighbor vessels with the same orientation as the main vessel did not contribute significantly to signal decay. The total number of particles simulated was also found to play a minor role in computing R2/ R2∗. PMID:18273394

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

    NASA Technical Reports Server (NTRS)

    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.

  15. Accuracy of 1H magnetic resonance spectroscopy for quantification of 2-hydroxyglutarate using linear combination and J-difference editing at 9.4T.

    PubMed

    Neuberger, Ulf; Kickingereder, Philipp; Helluy, Xavier; Fischer, Manuel; Bendszus, Martin; Heiland, Sabine

    2017-05-12

    Non-invasive detection of 2-hydroxyglutarate (2HG) by magnetic resonance spectroscopy is attractive since it is related to tumor metabolism. Here, we compare the detection accuracy of 2HG in a controlled phantom setting via widely used localized spectroscopy sequences quantified by linear combination of metabolite signals vs. a more complex approach applying a J-difference editing technique at 9.4T. Different phantoms, comprised out of a concentration series of 2HG and overlapping brain metabolites, were measured with an optimized point-resolved-spectroscopy sequence (PRESS) and an in-house developed J-difference editing sequence. The acquired spectra were post-processed with LCModel and a simulated metabolite set (PRESS) or with a quantification formula for J-difference editing. Linear regression analysis demonstrated a high correlation of real 2HG values with those measured with the PRESS method (adjusted R-squared: 0.700, p<0.001) as well as with those measured with the J-difference editing method (adjusted R-squared: 0.908, p<0.001). The regression model with the J-difference editing method however had a significantly higher explanatory value over the regression model with the PRESS method (p<0.0001). Moreover, with J-difference editing 2HG was discernible down to 1mM, whereas with the PRESS method 2HG values were not discernable below 2mM and with higher systematic errors, particularly in phantoms with high concentrations of N-acetyl-asparate (NAA) and glutamate (Glu). In summary, quantification of 2HG with linear combination of metabolite signals shows high systematic errors particularly at low 2HG concentration and high concentration of confounding metabolites such as NAA and Glu. In contrast, J-difference editing offers a more accurate quantification even at low 2HG concentrations, which outweighs the downsides of longer measurement time and more complex postprocessing. Copyright © 2017. Published by Elsevier GmbH.

  16. Superconducting Magnet Technology for Future High Energy Proton Colliders

    NASA Astrophysics Data System (ADS)

    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.

  17. Immunochemical and proton magnetic resonance studies of toxic venom proteins

    SciTech Connect

    Henderson, J.T.

    1986-01-01

    Immunochemical responses of a number of pit viper venoms to antibodies derived separately from the acidic and basic subunits of Mojave toxin isolated from the venom of Crotalus scutulatus scutulatus were investigated by enzyme linked immunosorbent assay (ELISA) and Ouchterlony immunodiffusion. The three-dimensional solution structure of myotoxin a isolated from the venom of Crotalus viridis viridis was studied by proton nuclear magnetic resonance techniques. Assignment of many resonance lines to their corresponding protons enabled detection of several residue specific interactions implicating existence of a three-dimensional structural feature of the molecule which is probably important to toxic activity. Finally, a computer program is presented that calculates the three-dimensional structure of a protein from dihedral angles and allows viewing of projections of the calculated structures on a standard display. This program is unique in that it is designed to operate on the microcomputers of the IBM PC family.

  18. Proton magnetic resonance spectroscopy of a gray matter heterotopia.

    PubMed

    Marsh, L; Lim, K O; Sullivan, E V; Lane, B; Spielman, D

    1996-12-01

    We used proton magnetic resonance spectroscopy to examine resonances representing metabolites containing N-acetyl (NA) groups (predominantly N-acetyl aspartate), choline, and creatine within a large left-hemispheric gray matter heterotopia (GMH) in a 35-year-old man with corpus callosum agenesis. In contrast to normal brain tissue, including gray matter regions, heterotopic gray matter was characterized by relatively increased choline and creatine resonances and a normal NA signal. These data suggest increased cellular activity or persistent immature neuronal tissue in GMH relative to unaffected tissue.

  19. Proton magnetic resonance spectroscopy: technique for the neuroradiologist.

    PubMed

    Cecil, Kim M

    2013-08-01

    Magnetic resonance spectroscopy (MRS) provides information on neuronal and axonal viability, energetics of cellular structures, and status of cellular membranes. Proton MRS appeals to clinicians and scientists because its application in the clinical setting can increase the specificity of MR imaging. The objective of this article is to provide descriptive concepts of the technique and its application in vivo for a variety of patient populations. When appropriately incorporating MRS into the neuroradiologic evaluation, this technique produces relevant information to radiologists and clinicians for their understanding of adult and pediatric neurologically based disease processes.

  20. ENERGETIC PROTONS, RADIONUCLIDES, AND MAGNETIC ACTIVITY IN PROTOSTELLAR DISKS

    SciTech Connect

    Turner, N. J.; Drake, J. F.

    2009-10-01

    We calculate the location of the magnetically inactive dead zone in the minimum-mass protosolar disk, under ionization scenarios including stellar X-rays, long- or short-lived radionuclide decay, and energetic protons arriving from the general interstellar medium, from a nearby supernova explosion, from the disk corona, or from the corona of the young star. The disk contains a dead zone in all scenarios except those with small dust grains removed and a fraction of the short-lived radionuclides remaining in the gas. All the cases without exception have an 'undead zone' where intermediate resistivities prevent magneto-rotational turbulence while allowing shear-generated large-scale magnetic fields. The mass column in the undead zone is typically greater than the column in the turbulent surface layers. The results support the idea that the dead and undead zones are robust consequences of cold, dusty gas with mass columns exceeding 1000 g cm{sup -2}.

  1. Energetic Protons, Radionuclides, and Magnetic Activity in Protostellar Disks

    NASA Astrophysics Data System (ADS)

    Turner, N. J.; Drake, J. F.

    2009-10-01

    We calculate the location of the magnetically inactive dead zone in the minimum-mass protosolar disk, under ionization scenarios including stellar X-rays, long- or short-lived radionuclide decay, and energetic protons arriving from the general interstellar medium, from a nearby supernova explosion, from the disk corona, or from the corona of the young star. The disk contains a dead zone in all scenarios except those with small dust grains removed and a fraction of the short-lived radionuclides remaining in the gas. All the cases without exception have an "undead zone" where intermediate resistivities prevent magneto-rotational turbulence while allowing shear-generated large-scale magnetic fields. The mass column in the undead zone is typically greater than the column in the turbulent surface layers. The results support the idea that the dead and undead zones are robust consequences of cold, dusty gas with mass columns exceeding 1000 g cm-2.

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

    NASA Astrophysics Data System (ADS)

    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

  3. Radiation effects of 200 MeV proton beams on Nd-Fe-B magnets

    NASA Astrophysics Data System (ADS)

    Ito, Y.; Yasuda, K.; Sasase, M.; Ishigami, R.; Hatori, S.; Ohashi, K.; Tanaka, S.

    2003-08-01

    Effects of 200 MeV proton irradiation on the re-magnetized Nd-Fe-B magnet (Shin-Etsu Chemical N48) were investigated. The dose dependence of the magnetic flux loss for the re-magnetized sample agreed well with that for the unirradiated one within the experimental accuracy. The N48 magnet, demagnetized by the radiation, had perfectly its magnetic properties of its unirradiated level by means of the re-magnetization.

  4. Nuclear magnetic resonance in sedimentary rocks: Effect of proton desorption rate

    NASA Astrophysics Data System (ADS)

    Mendelson, Kenneth S.

    1982-09-01

    In a discussion of nuclear magnetic resonance of protons in the pore fluid of sedimentary rocks, Cohen and Mendelson assumed that the desorption rate of protons from the rock surface is much faster than the relaxation rate of the magnetization for protons on the surface. In the present paper it is shown that this assumption is not necessary and conditions are established under which the analysis of Cohen and Mendelson is valid.

  5. High latitude proton precipitation and light-ion density profiles during the magnetic storm initial phase

    NASA Technical Reports Server (NTRS)

    Burch, J. L.

    1973-01-01

    Measurements of precipitating protons and light ion densities by experiments on OGO-4 indicate that widespread proton precipitation occurs in predawn hours during the magnetic storm initial phase from the latitude of the high-latitude ion trough, or plasmapause , up to Lambda 75 deg. A softening of the proton spectrum is apparent as the plasmapause is approached. The separation of the low-latitude precipitation boundaries for 7.3 kev and 23.8 kev protons is approximately 1 deg, compared with a 3.6 deg separation which has been computed using the formulas of Gendrin and Eather and Carovillano. Consideration of probable proton drift morphology leads to the conclusion that protons ase injected in predawn hours, with widespread precipitation occurring in the region outside the plasmapause. Protons less energetic than approximately 7 kev drift eastward, while the more energetic protons drift westward, producing the observed dawn-dusk asymmetry for the lower-energy protons.

  6. Quantitative Proton Magnetic Resonance Techniques for Measuring Fat

    PubMed Central

    Harry, Houchun; Kan, Hermien E.

    2014-01-01

    Accurate, precise, and reliable techniques for quantifying body and organ fat distributions are important tools in physiology research. They are critically needed in studies of obesity and diseases involving excess fat accumulation. Proton magnetic resonance methods address this need by providing an array of relaxometry-based (T1, T2) and chemical-shift-based approaches. These techniques can generate informative visualizations of regional and whole-body fat distributions, yield measurements of fat volumes within specific body depots, and quantify fat accumulation in abdominal organs and muscles. MR methods are commonly used to investigate the role of fat in nutrition and metabolism, to measure the efficacy of short and long-term dietary and exercise interventions, to study the implications of fat in organ steatosis and muscular dystrophies, and to elucidate pathophysiological mechanisms in the context of obesity and its comorbidities. The purpose of this review is to provide a summary of mainstream MR strategies for fat quantification. The article will succinctly describe the principles that differentiate water and fat proton signals, summarize advantages and limitations of various techniques, and offer a few illustrative examples. The article will also highlight recent efforts in MR of brown adipose tissue and conclude by briefly discussing some future research directions. PMID:24123229

  7. Blood species discrimination using proton nuclear magnetic resonance spectroscopy.

    PubMed

    Zailer, Elina; Diehl, Bernd W K; Monakhova, Yulia B

    2017-05-01

    Blood species identification is an important challenge in forensic science. Conventional methods used for blood species analysis are destructive and associated with time-consuming sample preparation steps. Nuclear magnetic resonance (NMR) spectroscopy is known for its nondestructive properties and fast results. This research study presents a proton ((1)H) NMR method to discriminate blood species including human, cat, dog, elephant, and bison. Characteristic signals acting as markers are observed for each species. Moreover, the data are evaluated by principle component analysis (PCA) and support vector machines (SVM). A 100% correct species recognition between human and nonhuman species is achieved using radial basis kernel function (RBF) and standardized data. The research study shows that (1)H NMR spectroscopy is a powerful tool for differentiating human and nonhuman blood showing a great significance to forensic science.

  8. Brain proton magnetic resonance spectroscopy for hepatic encephalopathy

    NASA Astrophysics Data System (ADS)

    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.

  9. Calibration of a compact magnetic proton recoil neutron spectrometer

    NASA Astrophysics Data System (ADS)

    Zhang, Jianfu; Ouyang, Xiaoping; Zhang, Xianpeng; Ruan, Jinlu; Zhang, Guoguang; Zhang, Xiaodong; Qiu, Suizheng; Chen, Liang; Liu, Jinliang; Song, Jiwen; Liu, Linyue; Yang, Shaohua

    2016-04-01

    Magnetic proton recoil (MPR) neutron spectrometer is considered as a powerful instrument to measure deuterium-tritium (DT) neutron spectrum, as it is currently used in inertial confinement fusion facilities and large Tokamak devices. The energy resolution (ER) and neutron detection efficiency (NDE) are the two most important parameters to characterize a neutron spectrometer. In this work, the ER calibration for the MPR spectrometer was performed by using the HI-13 tandem accelerator at China Institute of Atomic Energy (CIAE), and the NDE calibration was performed by using the neutron generator at CIAE. The specific calibration techniques used in this work and the associated accuracies were discussed in details in this paper. The calibration results were presented along with Monte Carlo simulation results.

  10. Rabi, the proton magnetic moment, and the ‘2-wire' magnet, 1931-34

    NASA Astrophysics Data System (ADS)

    Forman, Paul

    2001-04-01

    With the assistance of Gregory Breit, I.I. Rabi, at Columbia University, worked out in 1931 a method to determine the spin (not the magnetic moment) of atomic nuclei by deflecting an atomic beam of the isotope in question in a weak, but long, inhomogeneous magnetic field. Crucial to this method was that it required no exact knowledge of that field. When the sensational result -- µp = 2.5µ_Bohr(m_e/m_p) -- from Otto Stern's deflection of a beam of hydrogen molecules in a strong magnetic field became known late in 1932, its confirmation by another laboratory, preferably by another method, seemed urgent. No one else had the refined technique to reproduce Stern's experiment. But because the hydrogen electronic wave function was known, the Breit-Rabi technique was susceptible of extension in this case to the measurement of the magnetic moment of the proton - - but only with accurate knowledge of the magnetic field and field gradient traversed by the atomic hydrogen beam. To this end Rabi introduced the '2-wire' magnet, producing a weak field and uniform gradient that could be calculated rather than measured. This field configuration quickly came to be used in all magnetic deflection experiments in Rabi's laboratory, first as produced directly by electric currents, and subsequently as emulated in iron electromagnets in order to achieve the higher magnetic fields required by molecular beam magnetic resonance experiments from 1937 onward.

  11. Rabi, the proton magnetic moment, and the ¡2-wire¢ magnet, 1931-34

    NASA Astrophysics Data System (ADS)

    Forman, Paul

    2001-04-01

    With the assistance of Gregory Breit, I.I. Rabi, at Columbia University, worked out in 1931 a method to determine the spin (not the magnetic moment) of atomic nuclei by deflecting an atomic beam of the isotope in question in a weak, but long, inhomogeneous magnetic field. Crucial to this method was that it required no exact knowledge of that field. When the sensational result: p = 2.5:_Bohr(m_e/m_p) from Otto Stern's deflection of a beam of hydrogen molecules in a strong magnetic field became known late in 1932, its confirmation by another laboratory, preferably by another method, seemed urgent. No one else had the refined technique to reproduce Stern's experiment. But because the hydrogen electronic wave function was known, the Breit Rabi technique was susceptible of extension in this case to the measurement of the magnetic moment of the proton but only with accurate knowledge of the magnetic field and field gradient traversed by the atomic hydrogen beam. To this end Rabi introduced the '2 wire' magnet, producing a weak field and uniform gradient that could be calculated rather than measured. This field configuration quickly came to be used in all magnetic deflection experiments in Rabi's laboratory, first as produced directly by electric currents, and subsequently as emulated in iron electromagnets in order to achieve the higher magnetic fields required by molecular beam magnetic resonance experiments from 1937 onward.

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

    NASA Astrophysics Data System (ADS)

    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.

  13. Proton magnetic resonance spectroscopy in childhood brainstem lesions.

    PubMed

    Porto, L; Hattingen, E; Pilatus, U; Kieslich, M; Yan, B; Schwabe, D; Zanella, F E; Lanfermann, H

    2007-03-01

    Diagnosis of brainstem lesions in children based on magnetic resonance imaging alone is a challenging problem. Magnetic resonance spectroscopy (MRS) is a noninvasive technique for spatial characterization of biochemical markers in tissues and gives information regarding cell membrane proliferation, neuronal damage, and energy metabolism. We measured the concentrations of biochemical markers in five children with brainstem lesions and evaluated their potential diagnostic significance. Images and spectra were acquired on a 1.5-T imager. The concentrations of N-acetylaspartate, tetramethylamines (e.g., choline), creatine, phosphocreatine, lactate, and lipids were measured within lesions located at the brainstem using Point-resolved spectroscopy sequences. Diagnosis based on localized proton spectroscopy included brainstem glioma, brainstem encephalitis, demyelination, dysmyelination secondary to neurofibromatosis type 1 (NF 1), and possible infection or radiation necrosis. In all but one patient, diagnosis was confirmed by biopsy or by clinical follow-up. This small sample of patients suggests that MRS is important in the differential diagnosis between proliferative and nonproliferative lesions in patients without neurofibromatosis. Unfortunately, in cases of NF 1, MRS can have a rather misdiagnosis role.

  14. Estimation of changes in fitness components and antioxidant defense of Drosophila subobscura (Insecta, Diptera) after exposure to 2.4 T strong static magnetic field.

    PubMed

    Todorović, Dajana; Perić-Mataruga, Vesna; Mirčić, Dejan; Ristić-Djurović, Jasna; Prolić, Zlatko; Petković, Branka; Savić, Tatjana

    2015-04-01

    As an ecological factor, a magnetic field can affect insects causing a wide range of responses. The main purpose of this study was to analyze the fitness components (postembryonic development and viability of individuals) and the antioxidant defense (superoxide dismutase, catalase, and total glutathione) in laboratory strains of Drosophila subobscura, originating from oak and beech forests after exposure to the strong static magnet (2.4 T, VINCY Cyclotron magnet). The first instar larvae were placed near the north pole (N group) or the south pole (S group) of the magnet for 2 h. Oak and beech populations of D. subobscura had longer development time and lower viability in N and S groups compared to controls. These differences were significant only in S group of oak population and in N group of beech population. Total glutathione content was significantly decreased in both exposed groups of oak population, while catalase activity was significantly increased in both exposed groups of beech population. Being significantly decreased in both exposed groups of oak population and significantly increased in S group of beech population in comparison to controls, superoxide dismutase activity was observed in different values. According to the results, it can be stated that applied static magnetic field could be considered a potential stressor influencing the fitness components and antioxidant defense in Drosophila flies.

  15. Proton magnetic resonance spectroscopy in ecstasy (MDMA) users.

    PubMed

    Daumann, Jörg; Fischermann, Thomas; Pilatus, Ulrich; Thron, Armin; Moeller-Hartmann, Walter; Gouzoulis-Mayfrank, Euphrosyne

    2004-05-20

    The popular recreational drug 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) has well-recognized neurotoxic effects upon central serotonergic systems in animal studies. In humans, the use of MDMA has been linked to cognitive problems, particularly to deficits in long-term memory and learning. Recent studies with proton magnetic resonance spectroscopy (1H MRS) have reported relatively low levels of the neuronal marker N-acetylaspartate (NAA) in MDMA users, however, these results have been ambiguous. Moreover, the only available 1H MRS study of the hippocampus reported normal findings in a small sample of five MDMA users. In the present study, we compared 13 polyvalent ecstasy users with 13 matched controls. We found no differences between the NAA/creatine/phosphocreatine (Cr) ratios of users and controls in neocortical regions, and only a tendency towards lower NAA/Cr ratios in the left hippocampus of MDMA users. Thus, compared with cognitive deficits, 1H MRS appears to be a less sensitive marker of potential neurotoxic damage in ecstasy users. Copyright 2004 Elsevier Ireland Ltd.

  16. Proton nuclear magnetic resonance studies on brain edema

    SciTech Connect

    Naruse, S.; Horikawa, Y.; Tanaka, C.; Hirakawa, K.; Nishikawa, H.; Yoshizaki, K.

    1982-06-01

    The water in normal and edematous brain tissues of rats was studied by the pulse nuclear magnetic resonance (NMR) technique, measuring the longitudinal relaxation time (T1) and the transverse relaxation time (T2). In the normal brain, T1 and T2 were single components, both shorter than in pure water. Prolongation and separation of T2 into two components, one fast and one slow, were the characteristic findings in brain edema induced by both cold injury and triethyl tin (TET), although some differences between the two types of edema existed in the content of the lesion and in the degree of changes in T1 and T2 values. Quantitative analysis of T1 and T2 values in their time course relating to water content demonstrated that prolongation of T1 referred to the volume of increased water in tissues examined, and that two phases of T2 reflected the distribution and the content of the edema fluid. From the analysis of the slow component of T2 versus water content during edema formation, it was demonstrated that the increase in edema fluid was steady, and its content was constant during formation of TET-induced edema. On the contrary, during the formation of cold-injury edema, water-rich edema fluid increased during the initial few hours, and protein-rich edema fluid increased thereafter. It was concluded that proton NMR relaxation time measurements may provide new understanding in the field of brain edema research.

  17. Measurement of the ratio of the proton's electric to magnetic form factors by recoil polarization

    SciTech Connect

    Mark K. Jones; Hall A Collaboration

    1999-03-01

    The longitudinal and transverse polarizations of the outgoing proton were measured for the reaction {sup 1}H(e,e' p) at four-momentum transfer squared of 0.5 to 3.5 GeV{sup 2}. The ratio of the electric to magnetic form factors of the proton is proportional to the ratio of the transverse to longitudinal polarizations.

  18. ARTEMIS observations of the solar wind proton scattering function from lunar crustal magnetic anomalies

    NASA Astrophysics Data System (ADS)

    Poppe, A. R.; Halekas, J. S.; Lue, C.; Fatemi, S.

    2017-04-01

    Despite their small scales, lunar crustal magnetic fields are routinely associated with observations of reflected and/or backstreaming populations of solar wind protons. Solar wind proton reflection locally reduces the rate of space weathering of the lunar regolith, depresses local sputtering rates of neutrals into the lunar exosphere, and can trigger electromagnetic waves and small-scale collisionless shocks in the near-lunar space plasma environment. Thus, knowledge of both the magnitude and scattering function of solar wind protons from magnetic anomalies is crucial in understanding a wide variety of planetary phenomena at the Moon. We have compiled 5.5 years of ARTEMIS (Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon's Interaction with the Sun) observations of reflected protons at the Moon and used a Liouville tracing method to ascertain each proton's reflection location and scattering angles. We find that solar wind proton reflection is largely correlated with crustal magnetic field strength, with anomalies such as South Pole/Aitken Basin (SPA), Mare Marginis, and Gerasimovich reflecting on average 5-12% of the solar wind flux while the unmagnetized surface reflects between 0.1 and 1% in charged form. We present the scattering function of solar wind protons off of the SPA anomaly, showing that the scattering transitions from isotropic at low solar zenith angles to strongly forward scattering at solar zenith angles near 90°. Such scattering is consistent with simulations that have suggested electrostatic fields as the primary mechanism for solar wind proton reflection from crustal magnetic anomalies.

  19. 31P nuclear magnetic resonance study of the proton-irradiated KTiOPO4

    NASA Astrophysics Data System (ADS)

    Kim, Se-Hun; Lee, Cheol Eui

    2013-08-01

    31P nuclear magnetic resonance (NMR) was employed to study the effects of proton irradiation on KTiOPO4 (KTP) in view of the previously studied paramagnetic impurity doping effects. High-resolution 31P NMR measurements showed significant increase in the isotropic chemical shifts of the two inequivalent phosphorus sites in the proton-irradiated KTP system, indicating decrease in the electron density around the phosphorous nuclei. The 31P NMR linewidths of the KTP system manifested anomalies associated with the superionic transition and with the polaron formation, which became much weaker after proton irradiation. Besides, the activation energy of the charge carriers increased significantly after proton irradiation.

  20. Proton flare and magnetic storm effect in the vicinity of the Earth.

    PubMed

    Nealy, J E; Wilson, J W; Shea, M A; Smart, D F

    1994-10-01

    We have developed a model and associated computational procedure for estimating energetic proton exposures during a major solar proton event that occur in combination with a large magnetic storm. Transmission functions for solar protons are computed using geomagnetic vertical cutoff data for quiescent and disturbed conditions. Predicted exposures in low altitude polar orbit are found to be orders of magnitude greater for severe magnetic storm conditions than are corresponding exposures in the absence of major disturbances. We examine the response scenario for the events of November 1960 as an example.

  1. Proton flare and magnetic storm effect in the vicinity of the earth

    SciTech Connect

    Shea, M.A.; Smart, D.F.; Nealy, J.E.; Wilson, J.W.

    1994-12-31

    The authors have developed a model and associated computational procedure for estimating energetic proton exposures during a major solar proton event that occur in combination with a large magnetic storm. Transmission functions for solar protons are computed using geomagnetic vertical cutoff data for quiescent and disturbed conditions. Predicated exposures in low altitude polar orbit are found to be orders of magnitude greater for severe magnetic storm conditions than are corresponding exposures in the absence of major disturbances. The authors examine the response scenario for the events of November 1960 as an example.

  2. Direct high-precision measurement of the magnetic moment of the proton.

    PubMed

    Mooser, A; Ulmer, S; Blaum, K; Franke, K; Kracke, H; Leiteritz, C; Quint, W; Rodegheri, C C; Smorra, C; Walz, J

    2014-05-29

    One of the fundamental properties of the proton is its magnetic moment, µp. So far µp has been measured only indirectly, by analysing the spectrum of an atomic hydrogen maser in a magnetic field. Here we report the direct high-precision measurement of the magnetic moment of a single proton using the double Penning-trap technique. We drive proton-spin quantum jumps by a magnetic radio-frequency field in a Penning trap with a homogeneous magnetic field. The induced spin transitions are detected in a second trap with a strong superimposed magnetic inhomogeneity. This enables the measurement of the spin-flip probability as a function of the drive frequency. In each measurement the proton's cyclotron frequency is used to determine the magnetic field of the trap. From the normalized resonance curve, we extract the particle's magnetic moment in terms of the nuclear magneton: μp = 2.792847350(9)μN. This measurement outperforms previous Penning-trap measurements in terms of precision by a factor of about 760. It improves the precision of the forty-year-old indirect measurement, in which significant theoretical bound state corrections were required to obtain µp, by a factor of 3. By application of this method to the antiproton magnetic moment, the fractional precision of the recently reported value can be improved by a factor of at least 1,000. Combined with the present result, this will provide a stringent test of matter/antimatter symmetry with baryons.

  3. Direct high-precision measurement of the magnetic moment of the proton

    NASA Astrophysics Data System (ADS)

    Mooser, A.; Ulmer, S.; Blaum, K.; Franke, K.; Kracke, H.; Leiteritz, C.; Quint, W.; Rodegheri, C. C.; Smorra, C.; Walz, J.

    2014-05-01

    One of the fundamental properties of the proton is its magnetic moment, µp. So far µp has been measured only indirectly, by analysing the spectrum of an atomic hydrogen maser in a magnetic field. Here we report the direct high-precision measurement of the magnetic moment of a single proton using the double Penning-trap technique. We drive proton-spin quantum jumps by a magnetic radio-frequency field in a Penning trap with a homogeneous magnetic field. The induced spin transitions are detected in a second trap with a strong superimposed magnetic inhomogeneity. This enables the measurement of the spin-flip probability as a function of the drive frequency. In each measurement the proton's cyclotron frequency is used to determine the magnetic field of the trap. From the normalized resonance curve, we extract the particle's magnetic moment in terms of the nuclear magneton: μp = 2.792847350(9)μN. This measurement outperforms previous Penning-trap measurements in terms of precision by a factor of about 760. It improves the precision of the forty-year-old indirect measurement, in which significant theoretical bound state corrections were required to obtain µp, by a factor of 3. By application of this method to the antiproton magnetic moment, the fractional precision of the recently reported value can be improved by a factor of at least 1,000. Combined with the present result, this will provide a stringent test of matter/antimatter symmetry with baryons.

  4. Carbon-13 and proton magnetic resonance of mouse muscle.

    PubMed Central

    Fung, B M

    1977-01-01

    It is shown that roughly 4 mmol carbon atoms/g mouse muscle can give rise to a "high resolution" 13C NMR spectrum. From the 13C spectrum, it is estimated that the protons from mobile organic molecules or molecular segments amount to 6-8%of total nonrigid protons (organic plus water) in muscle. Their spin-spin relaxation times (T2) are of the order of 0.4-2 ms. At 37 degrees C, the proton spin-echo decay of mouse muscle changes rapidly with time after death, while that of mouse brain does not. PMID:890043

  5. Short-term administration of uridine increases brain membrane phospholipids precursors in healthy adults: a 31-phosphorus magnetic resonance spectroscopy study at 4T

    PubMed Central

    Agarwal, Nivedita; Sung, Young-Hoon; Jensen, J Eric; daCunha, Grace; Harper, David; Olson, David; Renshaw, Perry F

    2010-01-01

    Objectives Altered metabolism of membrane phospholipids has been implicated in bipolar disorder. In humans, uridine is an important precursor of cytidine diphosphate (CDP)-choline, which plays a critical role in phospholipid synthesis and is currently being evaluated as a potential treatment for bipolar depression. Methods A total of 17 healthy males (mean age ± SD: 32.73 ± 7.2 years; range: 21.8- 46.4 years) were enrolled in this study. Subjects underwent a 31-phosphorus magnetic resonance spectroscopy (31P-MRS) acquisition at baseline and then again after seven days of either 2 g of uridine or placebo administration. A two-dimensional chemical shift imaging 31P-MRS acquisition collected spectral data from a 4 × 4 cluster of voxels acquired in the axial plane encompassing the subcortical structures as well as frontaltemporal cortical gray and white matter. The slab thickness was 3 cm and the approximate total volume of brain sampled was 432 cm3. The spectra obtained were analyzed using a fully automated in-house fitting algorithm. A population-averaged generalized estimating equation was used to evaluate changes both in phosphomonoesters (PME) [phosphocholine (PCho) and phosphoethanolamine (PEtn)] and phosphodiesters (PDE) [glycerophosphocholine (GPCho) and glycerophosphethanolamine (GPEtn)]. Metabolite ratios were reported with respect to the total integrated 31P resonance area. Results The uridine group had significantly increased total PME and PEtn levels over the one-week period [6.32% and 7.17% for PME and PEtn, respectively (p < 0.001)]. Other metabolite levels such as PCho, PDE, GPEtn and GPCho showed no significant changes following either uridine or placebo (all p > 0.05). Conclusions This is the first study to report a direct effect of uridine on membrane phospholipid precursors in healthy adults using 31P-MRS. Sustained administration of uridine appears to increase PME in healthy subjects. Further investigation is required to clarify the effects of

  6. [To Test Glutamate Hypothesis for Schizophrenia Utilizing Proton Magnetic Resonance Spectroscopy].

    PubMed

    Tsugawa, Sachiko; Nakajima, Shin-Ichiro Luke

    2017-09-01

    Recent advancement in magnetic resonance spectroscopy (MRS) has elucidated the pathophysiology of mental illness, including schizophrenia. MRS is a neuroimaging technique that non-invasively measures chemicals, using nuclear magnetic resonance. This narrative review explains proton MRS (1H-MRS) and introduces pivotal studies to examine a glutamate hypothesis for schizophrenia, employing 1H-MRS.

  7. Effective heating of nonadiabatic protons in magnetic reconnection with a guide field

    NASA Astrophysics Data System (ADS)

    Usami, Shunsuke; Horiuchi, Ritoku; Ohtani, Hiroaki

    2017-09-01

    The mechanism of plasma heating through magnetic reconnection with a guide magnetic field is investigated by means of two-dimensional electromagnetic particle simulations. These simulations mimic the dynamics of two torus plasmas merging through magnetic reconnection in a spherical tokamak (ST) device. It is found that a large part of protons, which behave as nonadiabatic, are effectively heated in the downstream because a ring-like structure of proton velocity distribution is observed at a local point in the downstream. The characteristic features of the velocity distribution can be explained as the following proton motion. Upon entering the downstream across the separatrix, nonadiabatic protons suddenly feel the strong electromagnetic field in the downstream and move in the outflow direction while rotating mainly around the guide magnetic field. The protons gain kinetic energy not only on the separatrix but also in the downstream. This effective heating process can be interpreted as the "pickup," which, however, was thought to be responsible for only heavy ions. In this work, it is demonstrated that the pickup of protons is compatible with the known pickup theory in the cases in which the plasma beta is much less than 1, which is satisfied in STs.

  8. Noninvasive amide proton transfer magnetic resonance imaging in evaluating the grading and cellularity of gliomas.

    PubMed

    Bai, Yan; Lin, Yusong; Zhang, Wei; Kong, Lingfei; Wang, Lifu; Zuo, Panli; Vallines, Ignacio; Schmitt, Benjamin; Tian, Jie; Song, Xiaolei; Zhou, Jinyuan; Wang, Meiyun

    2017-01-24

    Using noninvasive magnetic resonance imaging techniques to accurately evaluate the grading and cellularity of gliomas is beneficial for improving the patient outcomes. Amide proton transfer imaging is a noninvasive molecular magnetic resonance imaging technique based on chemical exchange saturation transfer mechanism that detects endogenous mobile proteins and peptides in biological tissues. Between August 2012 and November 2015, a total number of 44 patients with pathologically proven gliomas were included in this study. We compared the capability of amide proton transfer magnetic resonance imaging with that of noninvasive diffusion-weighted imaging and noninvasive 3-dimensional pseudo-continuous arterial spin imaging in evaluating the grading and cellularity of gliomas. Our results reveal that amide proton transfer magnetic resonance imaging is a superior imaging technique to diffusion-weighted imaging and 3-dimensional pseudo-continuous arterial spin imaging in the grading of gliomas. In addition, our results showed that the Ki-67 index correlated better with the amide proton transfer-weighted signal intensity than with the apparent diffusion coefficient value or the cerebral blood flow value in the gliomas. Amide proton transfer magnetic resonance imaging is a promising method for predicting the grading and cellularity of gliomas.

  9. Noninvasive amide proton transfer magnetic resonance imaging in evaluating the grading and cellularity of gliomas

    PubMed Central

    Zhang, Wei; Kong, Lingfei; Wang, Lifu; Zuo, Panli; Vallines, Ignacio; Schmitt, Benjamin; Tian, Jie; Song, Xiaolei; Zhou, Jinyuan; Wang, Meiyun

    2017-01-01

    Using noninvasive magnetic resonance imaging techniques to accurately evaluate the grading and cellularity of gliomas is beneficial for improving the patient outcomes. Amide proton transfer imaging is a noninvasive molecular magnetic resonance imaging technique based on chemical exchange saturation transfer mechanism that detects endogenous mobile proteins and peptides in biological tissues. Between August 2012 and November 2015, a total number of 44 patients with pathologically proven gliomas were included in this study. We compared the capability of amide proton transfer magnetic resonance imaging with that of noninvasive diffusion-weighted imaging and noninvasive 3-dimensional pseudo-continuous arterial spin imaging in evaluating the grading and cellularity of gliomas. Our results reveal that amide proton transfer magnetic resonance imaging is a superior imaging technique to diffusion-weighted imaging and 3-dimensional pseudo-continuous arterial spin imaging in the grading of gliomas. In addition, our results showed that the Ki-67 index correlated better with the amide proton transfer-weighted signal intensity than with the apparent diffusion coefficient value or the cerebral blood flow value in the gliomas. Amide proton transfer magnetic resonance imaging is a promising method for predicting the grading and cellularity of gliomas. PMID:27992380

  10. Binding of calcium to phosphatidylcholines as determined by proton magnetic resonance and infrared spectroscopy.

    PubMed

    Yabusaki, K K; Wells, M A

    1975-01-14

    The interactions of calcium, magnesium, and the rare earth cations, cerium, neodymium, and praseodymium, with phosphatidylcholines were studied by proton magnetic resonance and infared spectroscopy. The calcium-induced chemical shifts for the various protons of phosphatidylcholine were C alpha choline greater than C beta choline greater than N(CH3)3 greater than C3 glycerol. No significant chemical shifts were observed for the C1 and C2 glycerol protons. None of the acyl chain protons were affected by the presence of calcium. Analysis of the salt-induced chemical shifts yielded binding curves with an excellent fit with the theoretical. The vicinal coupling constants for the various protons of phosphatidylcholine did not appear to change in the presence of calcium. The lanthanide-induced isotropic shifts for the protons of phosphatidylcholines followed the order Cbeta choline greater than C3 glycerol greater than Calpha choline greater than N(CH3)3. Examination of the P=O stretching band (1150-1300 cm-1) of phosphatidylcholines by differential infrared spectroscopy showed that this band shifted to shorter wavelengths in the presence of calcium. The site of calcium binding to phosphatidylcholines as deduced from the proton magnetic resonance and infrared data is discussed in light of the high specificity for calcium in enhancing the amino-catalyzed methanolysis of phosphatidylcholines.

  11. WE-D-17A-04: Magnetically Focused Proton Irradiation of Small Volume Targets

    SciTech Connect

    McAuley, G; Slater, J; Wroe, A

    2014-06-15

    Purpose: To explore the advantages of magnetic focusing for small volume proton irradiations and the potential clinical benefits for radiosurgery targets. The primary goal is to create narrow elongated proton beams of elliptical cross section with superior dose delivery characteristics compared to current delivery modalities (eg, collimated beams). In addition, more general beam shapes are also under investigation. Methods: Two prototype magnets consisting of 24 segments of samarium-cobalt (Sm2Co17) permanent magnetic material adhered into hollow cylinders were manufactured for testing. A single focusing magnet was placed on a positioning track on our Gantry 1 treatment table and 15 mm diameter proton beams with energies and modulation relevant to clinical radiosurgery applications (127 to 186 MeV, and 0 to 30 mm modulation) were delivered to a terminal water tank. Beam dose distributions were measured using a PTW diode detector and Gafchromic EBT2 film. Longitudinal and transverse dose profiles were analyzed and compared to data from Monte Carlo simulations analogous to the experimental setup. Results: The narrow elongated focused beam spots showed high elliptical symmetry indicating high magnet quality. In addition, when compared to unfocused beams, peak-to-entrance depth dose ratios were 11 to 14% larger (depending on presence or extent of modulation), and minor axis penumbras were 11 to 20% smaller (again depending on modulation) for focused beams. These results suggest that the use of rare earth magnet assemblies is practical and could improve dose-sparing of normal tissue and organs at risk while delivering enhanced dose to small proton radiosurgery targets. Conclusion: Quadrapole rare earth magnetic assemblies are a promising and inexpensive method to counteract particle out scatter that tends to degrade the peak to entrance performance of small field proton beams. Knowledge gained from current experiments will inform the design of a prototype treatment

  12. Direct high-precision measurement of the magnetic moment of the proton

    NASA Astrophysics Data System (ADS)

    Quint, Wolfgang

    2015-05-01

    The challenge to measure the properties of the proton with great precision inspires very different branches of physics. The magnetic moment of the proton is a fundamental property of this particle. So far it has only been measured indirectly, by analyzing the spectrum of an atomic hydrogen maser in a magnetic field. Here we report the direct high-precision measurement of the magnetic moment of a single proton using the double Penning-trap technique. We drive proton-spin quantum jumps by a radio-frequency field in a Penning trap with a homogeneous magnetic field. The induced spin transitions are detected in a second trap with a strong superimposed magnetic inhomogeneity. This enables the measurement of the spin-flip probability as a function of the drive frequency. In each measurement the proton's cyclotron frequency is used to determine the magnetic field of the trap. From the normalized resonance curve, we extract the particle's magnetic moment in terms of the nuclear magneton: μp = 2.792 847 350 (9) μN. This measurement outperforms previous Penning-trap measurements in terms of precision by a factor of about 760. It improves the precision of the forty year-old indirect measurement by D. Kleppner et al., in which significant theoretical bound-state corrections were required to obtain μp, by a factor of 3. By application of this method to the antiproton magnetic moment, the fractional precision of the recently reported value can be improved by a factor of at least 1,000. Combined with the present result, this will provide a stringent test of matter/antimatter symmetry with baryons. Deutsche Forschungsgemeinschaft, grant QU122/3.

  13. An analytical solution to proton Bragg peak deflection in a magnetic field.

    PubMed

    Wolf, Russell; Bortfeld, Thomas

    2012-09-07

    The role of MR imaging for image-guided radiation therapy (IGRT) is becoming more and more important thanks to the excellent soft tissue contrast offered by MRI. Hybrid therapy devices with integrated MRI scanners are under active development for x-ray therapy. The combination of proton therapy with MRI imaging has only been investigated at the theoretical or conceptual level. Of concern is the deflection of the proton beam in the homogeneous magnetic field. A previous publication has come to the conclusion that the impact of a 0.5 T magnetic field on the dose distribution for proton therapy is very small and lateral deflections stay well below 2 mm. The purpose of this study is to provide new insights into the effects of magnetic fields on a proton beam coming to rest in a patient. We performed an analytical calculation of the lateral deflection of protons with initial energies between 50 MeV and 250 MeV, perpendicular to the beam direction and the magnetic field. We used a power-law range-energy relationship and the Lorentz force in both relativistic and non-relativistic conditions. Calculations were done for protons coming to rest in water or soft tissue, and generalized to other uniform and non-uniform media. Results were verified by comparisons with numerical calculations and Monte Carlo simulations. A key result of our calculations is that the maximum lateral deflection at the end of range is proportional to the third power of the initial energy. Accordingly, due to the strong dependence on the energy, even a relatively small magnetic field of 0.5 T will cause a deflection of the proton beam by 1 cm at the end of range of a 200 MeV beam. The maximum deflection at 200 MeV is more than 10 times larger than that of a 90 MeV beam. Relativistic corrections of the deflection are generally small but they can become non-negligible at higher energies around 200 MeV and above. Contrary to previous findings, the lateral deflection of a proton beam can be significant (1

  14. Dynamics of the penetration boundaries of solar protons during a strong magnetic storm

    NASA Technical Reports Server (NTRS)

    Glukhov, G. A.; Kratenko, Y. P.; Mineev, Y. V.

    1985-01-01

    The variations in the equatorial penetration boundary of solar protons with E sub p = 0.9 to 8.0 MeV during a strong magnetic storm of April 3 to 5, were analyzed. The dynamics of this boundary is compared with the dynamics of the outer trapping boundary of electrons with E sub e = - 0.3 to 0.6 MeV. The solar-proton penetration and the structure of the real magnetic field are studied. The unique data on the thin structure of development of a magnetospheric substorm were obtained for the first time.

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

    SciTech Connect

    Kispert, Lowell D; Focsan, A Ligia; Konovalova, Tatyana A; Lawrence, Jesse; Bowman, Michael K; Dixon, David A; Molnar, Peter; Deli, Jozsef

    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 lengthening, a mechanism for nonradiative energy

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

    PubMed

    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.

  17. First application of proton reflection magnetometry with MESSENGER to estimate Mercury's surface magnetic field strength (Invited)

    NASA Astrophysics Data System (ADS)

    Winslow, R. M.; Johnson, C. L.; Anderson, B. J.; Gershman, D. J.; Raines, J. M.; Lillis, R. J.; Korth, H.; Slavin, J. A.; Solomon, S. C.

    2013-12-01

    We present the first use of proton reflection magnetometry, a novel adaptation of electron reflectometry, to estimate Mercury's surface field strength. We use measurements of protons by MESSENGER's Fast Imaging Plasma Spectrometer (FIPS) in 8-s integration times. Because of the limited field of view of FIPS, we average pitch-angle distributions by accumulating proton data from multiple integration periods and orbits over selected geographical regions. Proton loss cones are evident in both the northern hemisphere cusp region as well as on the nightside at low latitudes in the southern hemisphere. The existence of the loss cones provides confirmation of proton precipitation to the surface in these regions. The loss cone pitch-angle cut-offs are gradual rather than sharp, which we attribute in part to wave-particle scattering causing pitch-angle diffusion. Fitting diffusion curves to the pitch-angle distributions yields estimates of both the cut-off pitch angle, αc, and an average Dαt, where Dα is the pitch-angle diffusion coefficient and t is the diffusion time. The in-situ magnetic field together with αc provide an estimate of the surface magnetic field strength. The results are within 10% of a magnetospheric model for the surface field at the mapped surface locations, but are systematically lower than the model predictions. This discrepancy is consistent with the presence of near-surface plasma, which locally lowers the actual total magnetic field at the surface but is not included in the vacuum-field magnetospheric model. As consistency checks, we have confirmed that the loss cone size decreases with increasing altitude and that the surface magnetic field strength increases with increasing latitude. Our results confirm the offset dipole structure at the surface and demonstrate that proton reflection magnetometry is a practical method for inferring the surface magnetic field strength at Mercury. Further observations may resolve regional-scale structure in the

  18. Proton-nuclear magnetic resonance relaxation times in brain edema

    SciTech Connect

    Kamman, R.L.; Go, K.G.; Berendsen, H.J. )

    1990-01-01

    Proton relaxation times of protein solutions, bovine brain, and edematous feline brain tissue were studied as a function of water concentration, protein concentration, and temperature. In accordance with the fast proton exchange model for relaxation, a linear relation could be established between R1 and the inverse of the weight fraction of tissue water. This relation also applied to R2 of gray matter and of protein solutions. No straightforward relation with water content was found for R2 of white matter. Temperature-dependent studies indicated that in this case, the slow exchange model for relaxation had to be applied. The effect of macromolecules in physiological relevant concentrations on the total relaxation behavior of edematous tissue was weak. Total water content changes predominantly affected the relaxation rates. The linear relation may have high clinical potential for assessment of the status of cerebral edema on the basis of T1 and T2 readings from MR images.

  19. Correlation between proton anisotropy and magnetic field direction in the distant geotail

    NASA Technical Reports Server (NTRS)

    Klecker, B.; Scholer, M.; Hovestadt, D.; Gloeckler, G.; Ipavich, F. M.; Smith, E. J.; Tsurutani, B. T.

    1984-01-01

    A statistical analysis has been conducted of the anisotropy of suprathermal protons and the polarity of the magnetic field during April 10-16, 1983. At this time, ISEE-3 was at lunar distances in the geomagnetic tail of the earth, and well within the nominal magnetopause. The first-order anisotropy is presently correlated with the latitude angle and the z-component of the magnetic field. The anisotropy direction's frequency distribution is strongly peaked in the earthward and tailward direction, indicating fast earthward and tailward flows. For large anisotropies, and within 5 earth radii of the nominal neutral sheet position, a strong correlation is found between the earthward-streaming suprathermal protons and the northward polarity of the magnetic field; large tailward anisotropies are generally correlated with southward magnetic field polarity. This correlation is most simply interpreted in terms of a neutral line or reconnection model.

  20. Energetic protons, alpha particles, and electrons in magnetic flux transfer events

    NASA Technical Reports Server (NTRS)

    Scholer, M.; Hovestadt, D.; Ipavich, F. M.; Gloeckler, G.

    1982-01-01

    Energetic proton, alpha particle, and electron data are presented for two magnetopause crossings, which show magnetic field signatures characteristic of flux transfer events (FTEs). Energetic proton and alpha particles are observed streaming along the magnetic field within the magnetosheath in all events showing magnetic signatures characteristic of the FTEs. Flux ratios as high as about 180 parallel and antiparallel to the magnetic field are observed, which means that ions of about 30 keV per charge are at times streaming almost scatter-free from the magnetopause into the magnetosheath. Energetic ion bursts with signatures equal to those observed in FTEs are reduced by more than an order of magnitude as compared to the trapped particle flux.

  1. Comparison of self-gated and prospectively triggered fast low angle shot (FLASH) sequences for contrast-enhanced magnetic resonance imaging of the liver at 9.4 T in a rat model of colorectal cancer metastases.

    PubMed

    Fries, Peter; Seidel, Roland; Müller, Andreas; Matthes, Kathrin; Denda, Gero; Massmann, Alexander; Menger, Michael D; Sperling, Jens; Morelli, John N; Altmeyer, Katrin; Schneider, Günther; Buecker, Arno

    2013-10-01

    The aim of this study was to compare a retrospectively self-gated fast low angle shot sequence (RSG-FLASH) with a prospectively triggered fast low angle shot sequence (PT-FLASH) using an external trigger device for dynamic contrast-enhanced magnetic resonance imaging of the liver at 9.4 T in a rat model of colorectal cancer metastases. In 10 rats with hepatic metastases, we acquired an axial RSG-FLASH sequence through the liver. A FLASH sequence with prospective triggering (PT-FLASH) using an external trigger device was acquired at the same location with the same imaging parameters. After intravenous injection of 0.2 mmol/kg body weight of Gd-DTPA, alternating acquisitions of both sequences were performed at 4 consecutive time points.Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and lesion enhancement were obtained for liver tumors and parenchyma. In addition, we assessed the total acquisition times of the different imaging approaches for each acquisition, including triggering and gating. Two independent readers performed a qualitative evaluation of each sequence. Statistical analyses included paired t tests and Wilcoxon matched pairs signed rank tests. No statistically significant differences in SNR, CNR, or lesion enhancement were observed. Qualitative assessments of the sequences were comparable. However, acquisition times of PT-FLASH were significantly longer (mean [SD], 160.6 [25.7] seconds; P < 0.0001) and markedly variable (minimum, 120 seconds; maximum, 209 seconds), whereas the RSG-FLASH approach demonstrated a constant mean (SD) acquisition time of 59.0 (0) seconds. The RSG-FLASH and PT-FLASH sequences do not differ qualitatively or quantitatively regarding SNR, CNR, and lesion enhancement for magnetic resonance imaging of the liver in the rats at 9.4 T. However, the variability of acquisition times for the PT-FLASH sequences is a major factor of inconsistency, and we therefore consider this approach as inappropriate for dynamic contrast

  2. Variations in proton scanned beam dose delivery due to uncertainties in magnetic beam steering.

    PubMed

    Peterson, Stephen; Polf, Jerimy; Ciangaru, George; Frank, Steven J; Bues, Martin; Smith, Al

    2009-08-01

    The purpose of this work was to develop a method to calculate and study the impact of fluctuations in the magnetic field strengths within the steering magnets in a proton scanning beam treatment nozzle on the dose delivered to the patient during a proton therapy treatment. First, an analytical relationship between magnetic field uncertainties in the steering magnets and the resulting lateral displacements in the position of the delivered scanned beam "dose spot" was established. Next, using a simple 3D dose calculation code and data from a validated Monte Carlo model of the proton scanning beam treatment nozzle, the uniform dose delivery to a 3D treatment volume was calculated. The dose distribution was then recalculated using the calculated lateral displacements due to magnetic field fluctuations to the proton pencil beam position. Using these two calculated dose distributions, the clinical effects of the magnetic field fluctuations were determined. A deliberate displacement of four adjacent spots either toward or away from each other was used to determine the "maximum" dose impact, while a random displacement of all spots was used to establish a more realistic clinical dose impact. Changes in the dose volume histogram (DVH) and the presence of hot and cold spots in the treatment volume were used to quantify the impact of dose-spot displacement. A general analytical relationship between magnetic field uncertainty and final dose-spot position is presented. This analytical relationship was developed such that it can be applied to study magnetic beam steering for any scanned beam nozzle design. Using this relationship the authors found for the example beam steering nozzle used in this study that deliberate lateral displacements of 0.5 mm or random lateral displacements of up to 1.0 mm produced a noticeable dose impact (5% hot spot) in the treatment volume. A noticeable impact (3% decrease in treatment volume coverage) on the DVH was observed for random displacements

  3. Interpretation of Magnetization Transfer and Proton Cross-Relaxation Spectra of Biological Tissues

    NASA Astrophysics Data System (ADS)

    Tessier, J. J.; Dillon, N.; Carpenter, T. A.; Hall, L. D.

    1995-05-01

    Magnetization-tfansfer (MT) experiments have been performed at 300 MHz on agar gels, solutions of sodium alginate, bovine nasal cartilage, and postmortem porcine muscle, The experimental results elucidate MT mechanisms between mobile macromolecules (correlation time τC On the order of 10-8 s) and water, and demonstrate the need to incorporate their effects in the characterization of biological samples. In addition, the results obtained confirm a recently published three-spin-bath theoretical treatment for proton magnetization transfer.

  4. Proton spin-echo magnetometer: a novel approach for magnetic field measurement in residual field gradient

    NASA Astrophysics Data System (ADS)

    Shim, Jeong Hyun; Lee, Seong-Joo; Hwang, Seong-min; Yu, Kwon Kyu; Kim, Kiwoong

    2015-08-01

    We demonstrate a proton spin echo magnetometer, in which the interrogation time is not limited by T2* and can be prolonged to T2. Therefore, even under a severe field gradient, the precision of the measurement does not degrade. We devised a phase linearization method that enables accurate estimation of the precession frequency from a spin-echo train. With proton spins in deoxygenated tetramethylsilane and a superconducting quantum interference device-detected NMR system at KRISS, an average field of around 5 μT was measured with an uncertainty of 0.42 nT in the presence of a field gradient of 12.8 μT m-1. This implies that our system tolerated a 25% variation in magnetic field over the sample area. The proton spin-echo magnetometer will be useful in measuring magnetic fields without compensating for residual field gradients.

  5. Fundamental investigations of supported monometallic and bimetallic catalysts by proton magnetic resonance spectroscopy

    SciTech Connect

    Wu, Xi.

    1990-09-21

    Proton magnetic resonance spectroscopy, or nuclear magnetic resonance (NMR) of hydrogen, has been applied to investigate silica-supported Group VIII monometallic and Group VIII-Group IB bimetallic catalysts and alumina- and silica-supported platinum-rhenium bimetallic catalysts. Two adsorbed states of hydrogen, i.e., irreversible and reversible hydrogen, on the surfaces of monometallic Ru, Pt, and Cu particles and bimetallic Ru-Group Ib, Pt-Group Ib, and Pt-Re particles were observed directly via proton NMR. The same amounts of the irreversible hydrogen adsorbed on pure Ru catalysts were measured by both proton NMR and the volumetric technique. The electronic environments on surfaces of monometallic catalysts are sensitive to changes in metal dispersion, state of adsorbed hydrogen, and residual chlorine. Surface compositions for the Ru--Cu and Pt--Cu bimetallic catalysts were determined by NMR of adsorbed hydrogen. 297 refs., 96 figs., 19 tabs.

  6. Invited Article: Relation between electric and magnetic field structures and their proton-beam images

    SciTech Connect

    Kugland, N. L.; Ryutov, D. D.; Plechaty, C.; Ross, J. S.; Park, H.-S.

    2012-10-15

    Proton imaging is commonly used to reveal the electric and magnetic fields that are found in high energy density plasmas. Presented here is an analysis of this technique that is directed towards developing additional insight into the underlying physics. This approach considers: formation of images in the limits of weak and strong intensity variations; caustic formation and structure; image inversion to obtain line-integrated field characteristics; direct relations between images and electric or magnetic field structures in a plasma; imaging of sharp features such as Debye sheaths and shocks. Limitations on spatial and temporal resolution are assessed, and similarities with optical shadowgraphy are noted. Synthetic proton images are presented to illustrate the analysis. These results will be useful for quantitatively analyzing experimental proton imaging data and verifying numerical codes.

  7. Invited article: Relation between electric and magnetic field structures and their proton-beam images.

    PubMed

    Kugland, N L; Ryutov, D D; Plechaty, C; Ross, J S; Park, H-S

    2012-10-01

    Proton imaging is commonly used to reveal the electric and magnetic fields that are found in high energy density plasmas. Presented here is an analysis of this technique that is directed towards developing additional insight into the underlying physics. This approach considers: formation of images in the limits of weak and strong intensity variations; caustic formation and structure; image inversion to obtain line-integrated field characteristics; direct relations between images and electric or magnetic field structures in a plasma; imaging of sharp features such as Debye sheaths and shocks. Limitations on spatial and temporal resolution are assessed, and similarities with optical shadowgraphy are noted. Synthetic proton images are presented to illustrate the analysis. These results will be useful for quantitatively analyzing experimental proton imaging data and verifying numerical codes.

  8. Development of a compact proton scanning system in Uppsala with a moveable second magnet

    NASA Astrophysics Data System (ADS)

    Lorin, Stefan; Grusell, Erik; Tilly, Nina; Medin, Joakim; Blom, Mikael; Ziemann, Volker; Reistad, Dag; Glimelius, Bengt

    2000-05-01

    A scanned proton beam yields dose distributions that in most cases are superior to passively scattered proton beams and to other external radiation treatment modalities. The present paper gives a description of the scanning system that has been developed at the Svedberg Laboratory (TSL) in Uppsala. The scanning technique and the technical design are described. The solution with a small pole gap of the magnets and a moveable second magnet results in a very compact scanning head, which can therefore be incorporated in a gantry of relatively limited size. A prototype was constructed that has been used to realize various dose distributions with a scanned beam of 180 MeV protons at TSL.

  9. Glutamatergic Effects of Divalproex in Adolescents with Mania: A Proton Magnetic Resonance Spectroscopy Study

    ERIC Educational Resources Information Center

    Strawn, Jeffrey R.; Patel, Nick C.; Chu, Wen-Jang; Lee, Jing-Huei; Adler, Caleb M.; Kim, Mi Jung; Bryan, Holly S.; Alfieri, David C.; Welge, Jeffrey A.; Blom, Thomas J.; Nandagopal, Jayasree J.; Strakowski, Stephen M.; DelBello, Melissa P.

    2012-01-01

    Objectives: This study used proton magnetic resonance spectroscopy ([superscript 1]H MRS) to evaluate the in vivo effects of extended-release divalproex sodium on the glutamatergic system in adolescents with bipolar disorder, and to identify baseline neurochemical predictors of clinical remission. Method: Adolescents with bipolar disorder who were…

  10. Glutamatergic Effects of Divalproex in Adolescents with Mania: A Proton Magnetic Resonance Spectroscopy Study

    ERIC Educational Resources Information Center

    Strawn, Jeffrey R.; Patel, Nick C.; Chu, Wen-Jang; Lee, Jing-Huei; Adler, Caleb M.; Kim, Mi Jung; Bryan, Holly S.; Alfieri, David C.; Welge, Jeffrey A.; Blom, Thomas J.; Nandagopal, Jayasree J.; Strakowski, Stephen M.; DelBello, Melissa P.

    2012-01-01

    Objectives: This study used proton magnetic resonance spectroscopy ([superscript 1]H MRS) to evaluate the in vivo effects of extended-release divalproex sodium on the glutamatergic system in adolescents with bipolar disorder, and to identify baseline neurochemical predictors of clinical remission. Method: Adolescents with bipolar disorder who were…

  11. Proton nuclear magnetic resonance studies of boronated nucleosides

    SciTech Connect

    Banks, B.N.

    1992-01-01

    Modified nucleosides are an emerging class of potentially therapeutic agents. Recently, a number of 2[prime]-deoxynucleosides with boronated bases have been synthesized in this laboratory, including: 2[prime]-deoxy-N7-cyanoborano guanosine (bGua), 2[prime]-deoxy-N3-cyanoborano cytidine (bCyt), and 2[prime]-deoxy-N1-cyanoborano adenosine (bAde). The author has utilized proton NMR spectroscopy to determine the molecular recognition of these boronated nucleosides with their complementary base pairing partners. The self-association as well as heteroassociation were studied by varying the temperature, concentration, and mole fraction of each component. Proton NMR techniques include normal proton studies to measure the chemical shifts and homonuclear 1-D NOE difference to measure through space interactions, all of which help to determine the exact pairing behaviour of these nucleosides. Similar studies have been performed on unboronated nucleosides in order to determine if the boronated nucleosides can form stable Watson-Crick type base pairs; similar to unboronated nucleosides. From the results, the author concludes that bGua forms a stable Watson-Crick type base pair with Cyt. Both bGua and Cyt are able to self associate although the homodimers are less stable than the bGua:Cyt heterodimers. The other two boronated nucleosides because the cyanoborane group blocks the normal base pairing sites. The results are consistent with Hoogsteen pairing. Continuous variation studies suggest the existence of trimers of bCyt with Gua[sub 2] as well as other possible pairing schemes. The ability of bGua to complex with Cyt in a Watson-Crick type base pair suggests that it might be able to be incorporated like normal Gua into DNA.

  12. Evaluation of brain edema using magnetic resonance proton relaxation times

    SciTech Connect

    Fu, Y.; Tanaka, K.; Nishimura, S. )

    1990-01-01

    Experimental and clinical studies on the evaluation of water content in cases of brain edema were performed in vivo, using MR proton relaxation times (longitudinal relaxation time, T1; transverse relaxation time, T2). Brain edema was produced in the white matter of cats by the direct infusion method. The correlations between proton relaxation times obtained from MR images and the water content of white matter were studied both in autoserum-infused cats and in saline-infused cats. The correlations between T1 as well as T2 and the water content in human vasogenic brain edema were also examined and compared with the data obtained from the serum group. T1 and T2 showed good correlations with the water content of white matter not only in the experimental animals but also in the clinical cases. The quality of the edema fluid did not influence relaxation time and T1 seemed to represent almost solely the water content of the tissue. T2, however, was affected by the nature of existence of water and was more sensitive than T1 in detecting extravasated edema fluid. It seems feasible therefore to evaluate the water content of brain edema on the basis of T1 values.

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

    PubMed

    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.

  14. Captodative substituted C4H7O+2 carbenium ions and their relationship with the proton-bound complex CH3---CH=O tu4 tCCH2=C=O

    NASA Astrophysics Data System (ADS)

    Burgers, Peter C.; Jan van den Berg, Klaas; Visser, Herman; Terlouw, Johan K.

    1990-12-01

    The carboxy propylium ions CH3CH2---1H---COOH, CH3---1H---CH2COOH and (CH3)21---COOH have been generated in the gas phase by loss of I. from the respective ionized iodo acids. The straight chain isomers interconvert rapidly with themselves and with CH2=CH---CH2---1(OH)2. The major unimolecular dissociation products are CH3CH=CH---1=O + H2O and CH3---1=O + CH3CH=O, together with some CH31HOH + CH2=C=O. Loss of H2O is proposed to occur directly from CH3CH2---1H---COOH; formation of CH3---1=O and CH3---1(H)---OH involves rearrangement of CH3CH2---1H---COOH to CH3CH(OH)CH2---1=O which, as shown by neutralization-reionization (NR) experiments collapses to the ion CH3---CH=O tu4 ... CH2=C=O, formally proton bound acetaldehyde/ketene. It is this species which is sampled in metastable ion (MI), collisional activation (CA) and NR experiments. Thus in the CA mass spectra of the carboxypropylium ions m/z 43, CH3---1=O, and m/z 45, CH3---1(H)---OH, are dominant peaks; upon neutralization the bridged condensate falls apart to CH3CH=O and CH3=O which is, thermodynamically and kinetically, the most favourable dissociation. Our work shows that insight into the mechanisms of fast isomerization reactions of molecular ions may greatly assist the confident interpretation of the mass spectra of unknowns. Thus for example the puzzling observation that m/z 43, CH3---1=O, is base peak in the normal electron impact mass spectrum of the hydroxy ester CH3CH2CH(OH)CH2COOCH3, methyl 3-hydroxy pentanoate, can now easily be rationalized.

  15. Eddy current analysis and optimization of fast scanning magnet for a proton therapy system

    NASA Astrophysics Data System (ADS)

    Liu, Xu; Qin, Bin; Liu, Kaifeng; Chen, Wei; Liang, Zhikai; Chen, Qushan; Chen, Dezhi; Fan, Mingwu

    2017-08-01

    Proton therapy is now recognized as one of the most effective radiation therapy methods for cancers. A proton therapy facility with multiple gantry treatment rooms is under development in HUST (Huazhong University of Science and Technology), which is based on isochronous superconducting cyclotron scheme. In the beam line, the scanning system spreads out the proton beam on the target according to the complex tumour shape by two scanning magnets for horizontal and vertical scanning independently. Since these two magnets are excited by alternating currents and the maximum repetition frequency is up to 100 Hz, eddy currents and losses are expected to be significant. Slits are proven to be an effective way to reduce the eddy currents. To evaluate the heat distribution due to eddy losses in the pole end of the scanning magnet, the transient electromagnetic analysis and steady-state thermal analysis are performed. This paper describes design considerations of the scanning system and mainly analyses the eddy current effect of the scanning magnets. Different coil shapes and slit arrangements are simulated and compared to obtain the optimal configuration. The maximum temperatures of two magnets are optimized below 70 °C. In addition, the lag effect due to eddy currents is also discussed.

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

    PubMed

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

    2009-11-20

    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 1x10;{6} 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} greater, similar1) along the mirror instability threshold but small elsewhere, consistent with expectations of the mirror mode. We also show that the short wavelength magnetic fluctuation power is a strong function of collisionality, which relaxes the temperature anisotropy away from the instability conditions and reduces correspondingly the fluctuation power.

  17. Ultrafast proton radiography of the magnetic fields generated by a laser-driven coil current

    SciTech Connect

    Gao, Lan; Ji, Hantao; Fiksel, Gennady; Fox, William; Evans, Michelle; Alfonso, Noel

    2016-04-15

    Magnetic fields generated by a current flowing through a U-shaped coil connecting two copper foils were measured using ultrafast proton radiography. Two ~ 1.25 kJ, 1-ns laser pulses propagated through laser entrance holes in the front foil and were focused to the back foil with an intensity of ~ 3 x 1016 W/cm2. The intense laser-solid interaction induced a high voltage between the copper foils and generated a large current in the connecting coil. The proton data show ~ 40-50 T magnetic fields at the center of the coil ~ 3-4 ns after laser irradiation. In conclusion, the experiments provide significant insight for future target designs that aim to develop a powerful source of external magnetic fields for various applications in high-energy-density science.

  18. Ultrafast proton radiography of the magnetic fields generated by a laser-driven coil current

    DOE PAGES

    Gao, Lan; Ji, Hantao; Fiksel, Gennady; ...

    2016-04-15

    Magnetic fields generated by a current flowing through a U-shaped coil connecting two copper foils were measured using ultrafast proton radiography. Two ~ 1.25 kJ, 1-ns laser pulses propagated through laser entrance holes in the front foil and were focused to the back foil with an intensity of ~ 3 x 1016 W/cm2. The intense laser-solid interaction induced a high voltage between the copper foils and generated a large current in the connecting coil. The proton data show ~ 40-50 T magnetic fields at the center of the coil ~ 3-4 ns after laser irradiation. In conclusion, the experiments providemore » significant insight for future target designs that aim to develop a powerful source of external magnetic fields for various applications in high-energy-density science.« less

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

    SciTech Connect

    Zhang, Jianfu Ouyang, Xiaoping; Zhang, Xianpeng; Qiu, Suizheng; Zhang, Guoguang; Ruan, Jinlu; Zhang, Xiaodong; Yang, Shaohua; Song, Jiwen; Liu, Linyue; Li, Hongyun

    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.

  20. Ultrafast proton radiography of the magnetic fields generated by a laser-driven coil current

    SciTech Connect

    Gao, Lan; Ji, Hantao; Fiksel, Gennady; Fox, William; Evans, Michelle; Alfonso, Noel

    2016-04-15

    Magnetic fields generated by a current flowing through a U-shaped coil connecting two copper foils were measured using ultrafast proton radiography. Two ∼1.25 kJ, 1-ns laser pulses propagated through laser entrance holes in the front foil and were focused to the back foil with an intensity of ∼3 × 10{sup 16 }W/cm{sup 2}. The intense laser-solid interaction induced a high voltage between the copper foils and generated a large current in the connecting coil. The proton data show ∼40–50 T magnetic fields at the center of the coil ∼3–4 ns after laser irradiation. The experiments provide significant insight for future target designs that aim to develop a powerful source of external magnetic fields for various applications in high-energy-density science.

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

    PubMed

    Zhang, Jianfu; Ouyang, Xiaoping; Qiu, Suizheng; Zhang, Guoguang; Ruan, Jinlu; Zhang, Xiaodong; Zhang, Xianpeng; Yang, Shaohua; Song, Jiwen; Liu, Linyue; Li, Hongyun

    2015-12-01

    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(-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

    SciTech Connect

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

    2009-11-20

    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 1x10{sup 6} 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{sub ||} > or approx. 1) along the mirror instability threshold but small elsewhere, consistent with expectations of the mirror mode. We also show that the short wavelength magnetic fluctuation power is a strong function of collisionality, which relaxes the temperature anisotropy away from the instability conditions and reduces correspondingly the fluctuation power.

  3. Magnetism in MoS{sub 2} induced by proton irradiation

    SciTech Connect

    Mathew, S.; Gopinadhan, K.; Dhar, S.; Venkatesan, T.; Chan, T. K.; Yu, X. J.; Zhan, D.; Shen, Z. X.; Cao, L.; Rusydi, A.; Breese, M. B. H.; Thong, John T. L.

    2012-09-03

    Molybdenum disulphide, a diamagnetic layered dichalcogenide solid, is found to show magnetic ordering at room temperature when exposed to a 2 MeV proton beam. The temperature dependence of magnetization displays ferrimagnetic behavior with a Curie temperature of 895 K. A disorder mode corresponding to a zone-edge phonon and a Mo valence higher than +4 has been detected in the irradiated samples using Raman and x-ray photoelectron spectroscopy, respectively. The possible origins of long-range magnetic ordering in irradiated MoS{sub 2} samples are discussed.

  4. The effect of magnetically induced linear aggregates on proton transverse relaxation rates of aqueous suspensions of polymer coated magnetic nanoparticles.

    PubMed

    Saville, Steven L; Woodward, Robert C; House, Michael J; Tokarev, Alexander; Hammers, Jacob; Qi, Bin; Shaw, Jeremy; Saunders, Martin; Varsani, Rahi R; St Pierre, Tim G; Mefford, O Thompson

    2013-03-07

    It has been recently reported that for some suspensions of magnetic nanoparticles the transverse proton relaxation rate, R(2), is dependent on the time that the sample is exposed to an applied magnetic field. This time dependence has been linked to the formation of linear aggregates or chains in an applied magnetic field via numerical modeling. It is widely known that chain formation occurs in more concentrated ferrofluids systems and that this has an affect on the ferrofluid properties. In this work we examine the relationships between colloidal stability, the formation of these linear structures, and changes observed in the proton transverse relaxation rate of aqueous suspensions of magnetic particles. A series of iron oxide nanoparticles with varying stabilizing ligand brush lengths were synthesized. These systems were characterized with dynamic light scattering, transmission electron microscopy, dark-field optical microscopy, and proton transverse relaxation rate measurements. The dark field optical microscopy and R(2) measurements were made in similar magnetic fields over the same time scale so as to correlate the reduction of the transverse relaxivity with the formation of linear aggregates. Our results indicate that varying the ligand length has a direct effect on the colloidal arrangement of the system in a magnetic field, producing differences in the rate and size of chain formation, and hence systematic changes in transverse relaxation rates over time. With increasing ligand brush length, attractive inter-particle interactions are reduced, which results in slower aggregate formation and shorter linear aggregate length. These results have implications for the stabilization, characterization and potentially the toxicity of magnetic nanoparticle systems used in biomedical applications.

  5. Proton Exchange Rates Measured by Saturation Transfer Using Delayed Randomization of the Solvent Magnetization

    NASA Astrophysics Data System (ADS)

    Leijon, Mikael

    1996-08-01

    The spin-lock saturation transfer experiment introduced by B. Adams and L. Lerner (J. Magn. Reson.96, 604-607, 1992) is analyzed in terms of the Bloch equations. It is shown that theT1ρrelaxation of the solvent is introduced in the decay of the exchangeable protons under conditions of relatively rapid exchange. An alternative experiment is suggested that randomizes the solvent magnetization with a pulsed field gradient before the observe pulse. This gives a single exponential intensity decay for the exchanging protons at all exchange rates. In addition, efficient water suppression and an even excitation profile are obtained.

  6. Ion cooling in the plasmasphere during magnetic storm initial phase: modeling the proton temperature dynamics.

    NASA Astrophysics Data System (ADS)

    Kotova, Galina; Verigin, Mikhail; Bezrukikh, Vladilen

    The effect of ion temperature decreasing at L ¡ 3 during geomagnetic storm development was recently revealed by INTERBALL 2 and MAGION 5 thermal plasma data. A model of proton drift outward from the Earth caused by magnetic field decreasing in the inner plasmasphere is considered. Conservation of the first adiabatic invariant results in proton cooling during their outward motion. It is shown that model temperatures well agree with experimental data. The work is partially supported by the RAS programs P16 and OFN 15.

  7. The effects of 8 Helios observed solar proton events of interplanetary magnetic field fluctuations

    NASA Technical Reports Server (NTRS)

    ValdezGalicia, J. F.; Alexander, P.; Otaola, J. A.

    1995-01-01

    There have been recent suggestions that large fluxes during solar energetic particle events may produce their own turbulence. To verify this argument it becomes essential to find out whether these flows cause an enhancement of interplanetary magnetic field fluctuations. In the present work, power and helicity spectra of the IMF before, during and after 8 Helios-observed solar proton events in the range 0.3 - 1 AU are analyzed. In order to detect proton self generated waves, the time evolution of spectra are followed.

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

    PubMed

    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.

  9. The effects of 8 Helios observed solar proton events of interplanetary magnetic field fluctuations

    NASA Technical Reports Server (NTRS)

    ValdezGalicia, J. F.; Alexander, P.; Otaola, J. A.

    1995-01-01

    There have been recent suggestions that large fluxes during solar energetic particle events may produce their own turbulence. To verify this argument it becomes essential to find out whether these flows cause an enhancement of interplanetary magnetic field fluctuations. In the present work, power and helicity spectra of the IMF before, during and after 8 Helios-observed solar proton events in the range 0.3 - 1 AU are analyzed. In order to detect proton self generated waves, the time evolution of spectra are followed.

  10. Alternating-gradient canted cosine theta superconducting magnets for future compact proton gantries

    DOE PAGES

    Wan, Weishi; Brouwer, Lucas; Caspi, Shlomo; ...

    2015-10-23

    We present a design of superconducting magnets, optimized for application in a gantry for proton therapy. We have introduced a new magnet design concept, called an alternating-gradient canted cosine theta (AG-CCT) concept, which is compatible with an achromatic layout. This layout allows a large momentum acceptance. The 15 cm radius of the bore aperture enables the application of pencil beam scanning in front of the SC-magnet. The optical and dynamic performance of a gantry based on these magnets has been analyzed using the fields derived (via Biot-Savart law) from the actual windings of the AG-CCT combined with the full equationsmore » of motion. The results show that with appropriate higher order correction, a large 3D volume can be rapidly scanned with little beam shape distortion. A very big advantage is that all this can be done while keeping the AG-CCT fields fixed. This reduces the need for fast field ramping of the superconducting magnets between the successive beam energies used for the scanning in depth and it is important for medical application since this reduces the technical risk (e.g., a quench) associated with fast field changes in superconducting magnets. For proton gantries the corresponding superconducting magnet system holds promise of dramatic reduction in weight. For heavier ion gantries there may furthermore be a significant reduction in size.« less

  11. Alternating-gradient canted cosine theta superconducting magnets for future compact proton gantries

    NASA Astrophysics Data System (ADS)

    Wan, Weishi; Brouwer, Lucas; Caspi, Shlomo; Prestemon, Soren; Gerbershagen, Alexander; Schippers, Jacobus Maarten; Robin, David

    2015-10-01

    We present a design of superconducting magnets, optimized for application in a gantry for proton therapy. We have introduced a new magnet design concept, called an alternating-gradient canted cosine theta (AG-CCT) concept, which is compatible with an achromatic layout. This layout allows a large momentum acceptance. The 15 cm radius of the bore aperture enables the application of pencil beam scanning in front of the SC-magnet. The optical and dynamic performance of a gantry based on these magnets has been analyzed using the fields derived (via Biot-Savart law) from the actual windings of the AG-CCT combined with the full equations of motion. The results show that with appropriate higher order correction, a large 3D volume can be rapidly scanned with little beam shape distortion. A very big advantage is that all this can be done while keeping the AG-CCT fields fixed. This reduces the need for fast field ramping of the superconducting magnets between the successive beam energies used for the scanning in depth and it is important for medical application since this reduces the technical risk (e.g., a quench) associated with fast field changes in superconducting magnets. For proton gantries the corresponding superconducting magnet system holds promise of dramatic reduction in weight. For heavier ion gantries there may furthermore be a significant reduction in size.

  12. Measurement of lateral diffusion rates in membranes by pulsed magnetic field gradient, magic angle spinning-proton nuclear magnetic resonance.

    PubMed

    Gawrisch, Klaus; Gaede, Holly C

    2007-01-01

    Membrane organization, including the presence of domains, can be characterized by measuring lateral diffusion rates of lipids and membrane-bound substances. Magic angle spinning (MAS) yields well-resolved proton nuclear magnetic resonance (NMR) of lipids in biomembranes. When combined with pulsed-field gradient NMR (rendering what is called "pulsed magnetic field gradients-MAS-NMR"), it permits precise diffusion measurements on the micrometer lengths scale for any substance with reasonably well-resolved proton MAS-NMR resonances, without the need of preparing oriented samples. Sample preparation procedures, the technical requirements for the NMR equipment, and spectrometer settings are described. Additionally, equations for analysis of diffusion data obtained from unoriented samples, and a method for correcting the data for liposome curvature are provided.

  13. Nuclear magnetic resonance multiwindow analysis of proton local fields and magnetization distribution in natural and deuterated mouse muscle.

    PubMed Central

    Peemoeller, H; Pintar, M M

    1979-01-01

    The proton free-induction decays, spin-spin relaxation times, local fields in the rotating frame, and spin-lattice relaxation times in the laboratory and rotating frames, in natural and fully deuterated mouse muscle, are reported. Measurements were taken above and below freezing temperature and at two time windows on the free-induction decay. A comparative analysis show that the magnetization fractions deduced from the different experiments are in good agreement. The main conclusion is that the resolution of the (heterogeneous) muscle nuclear magnetic resonance (NMR) response is improved by the multiwindow analysis. PMID:262554

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

    SciTech Connect

    McAuley, GA; Slater, JM; Slater, JD; Wroe, AJ

    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.

  15. Proton magnetic resonance spectroscopy for the diagnosis and management of cerebral disorders.

    PubMed

    Rudkin, T M; Arnold, D L

    1999-08-01

    The use of magnetism in medicine has a long and colorful history since its legendary discovery in the Western world by the shepherd Magnes. More recent use of magnetism has centered on nuclear magnetic resonance. Magnetic resonance spectroscopy (MRS) provides chemical information on tissue metabolites. Both hydrogen 1 (1H) and phosphorus 31 resonances have been used to study brain tissue, but the magnetic resonance sensitivity for protons is far greater than it is for phosphorus. One of the most important contributions of 1H-MRS to clinical neurology is its ability to quantify neuronal loss and to demonstrate reversible neuronal damage. 1H-magnetic resonance spectroscopy has been found to be a useful research tool in elucidating the pathophysiology underlying certain diseases. This review focuses on the use of proton MRS to study various neurologic diseases, including epilepsy, multiple sclerosis, brain tumors, human immunodeficiency virus 1-associated neurologic disorders, as well as cerebrovascular, neurodegenerative, and metabolic diseases. It highlights the contributions of 1H-MRS to the diagnosis and the monitoring of these neurologic diseases that make it a useful adjunct in patient management.

  16. Amplification of Collective Magnetic Fluctuations in Magnetized Bi-Maxwellian Plasmas for Parallel Wave Vectors. I. Electron-Proton Plasma

    NASA Astrophysics Data System (ADS)

    Vafin, S.; Schlickeiser, R.; Yoon, P. H.

    2016-09-01

    The general electromagnetic fluctuation theory is a powerful tool to analyze the magnetic fluctuation spectrum of a plasma. Recent works utilizing this theory for a magnetized non-relativistic isotropic Maxwellian electron-proton plasma have demonstrated that the equilibrium ratio of | δ B| /{B}0 can be as high as 10-12. This value results from the balance between spontaneous emission of fluctuations and their damping, and it is considerably smaller than the observed value | δ B| /{B}0 in the solar wind at 1 au, where {10}-3≲ | δ B| /{B}0≲ {10}-1. In the present manuscript, we consider an anisotropic bi-Maxwellian distribution function to investigate the effect of plasma instabilities on the magnetic field fluctuations. We demonstrate that these instabilities strongly amplify the magnetic field fluctuations and provide a sufficient mechanism to explain the observed value of | δ B| /{B}0 in the solar wind at 1 au.

  17. Magnetic properties of proton irradiated BiFeO{sub 3}

    SciTech Connect

    Han, Seungkyu; Jin Kim, Sam; Sung Kim, Chul

    2013-05-07

    The crystal structure and magnetic properties of BiFeO{sub 3} samples, proton-irradiated with 0, 10, and 20 pC/{mu}m{sup 2}, were investigated with x-ray diffraction (XRD), vibrating sample magnetometer, and Moessbauer spectroscopy measurements. From the Rietveld refinement analysis of the XRD patterns, the crystal structure of BiFeO{sub 3} is determined to be rhombohedral with the space group of R3c. We have observed the decrease in the lattice constant and oxygen occupancy with proton irradiation. The magnetization hysteresis (M-H) curves show the appearance of the weak ferromagnetic behavior in the proton irradiated BiFeO{sub 3} samples. The Moessbauer spectra of proton irradiated BiFeO{sub 3} samples at 295 K were analyzed with two-sextets (B{sub 1} and B{sub 2}) and doublet. From the isomer shift ({delta}) values, ionic states were determined to be Fe{sup 3+}. Compared to non-irradiated sample, having the antiferromagnetic area ratio (two-sextets) of 45.47, 54.53% the antiferromagnetic and paramagnetic area ratios (doublet) of 10 and 20 pC/{mu}m{sup 2} proton irradiated BiFeO{sub 3} samples are 41.36, 51.26, and 7.38% and 41.03, 50.90, and 8.07%, respectively. Our experimental observation suggests that the increase in the paramagnetic area ratio is due to the disappearance of superexchange interaction, resulted from the removal of the oxygen with proton irradiation. Also, the appearance of the weak ferromagnetic behavior is caused by the breaking of the antiferromagnetic coupling.

  18. [Experiment and analyse on the effect of magnetic nanoparticles upon relaxation time of proton in molecular recognition by MRI].

    PubMed

    Hu, Lili; Song, Tao; Yang, Wenhui; Wang, Ming; Zhang, Fang; Tao, Chunjing

    2007-06-01

    To research on the effect of three different magnetic nanoparticles upon relaxation time of proton. The detection by magnetic resonance imaging (MRI) indicates that there is the effect of marked difference to right control experiment and to analyze the difference from theory. The result discloses that will be able to perform the experiment of molecular recognition using magnetic nanoparticles later.

  19. Multimodal neuroimaging in humans at 9.4 T: a technological breakthrough towards an advanced metabolic imaging scanner.

    PubMed

    Shah, N Jon

    2015-07-01

    The aim of this paper is twofold: firstly, to explore the potential of simultaneously acquiring multimodal MR-PET-EEG data in a human 9.4 T scanner to provide a platform for metabolic brain imaging. Secondly, to demonstrate that the three modalities are complementary, with MRI providing excellent structural and functional imaging, PET providing quantitative molecular imaging, and EEG providing superior temporal resolution. A 9.4 T MRI scanner equipped with a PET insert and a commercially available EEG device was used to acquire in vivo proton-based images, spectra, and sodium- and oxygen-based images with MRI, EEG signals from a human subject in a static 9.4 T magnetic field, and demonstrate hybrid MR-PET capability in a rat model. High-resolution images of the in vivo human brain with an isotropic resolution of 0.5 mm and post-mortem brain images of the cerebellum with an isotropic resolution of 320 µm are presented. A (1)H spectrum was also acquired from 2 × 2 × 2 mm voxel in the brain allowing 12 metabolites to be identified. Imaging based on sodium and oxygen is demonstrated with isotropic resolutions of 2 and 5 mm, respectively. Auditory evoked potentials measured in a static field of 9.4 T are shown. Finally, hybrid MR-PET capability at 9.4 T in the human scanner is demonstrated in a rat model. Initial progress on the road to 9.4 T multimodal MR-PET-EEG is illustrated. Ultra-high resolution structural imaging, high-resolution images of the sodium distribution and proof-of-principle (17)O data are clearly demonstrated. Further, simultaneous MR-PET data are presented without artefacts and EEG data successfully corrected for the cardioballistic artefact at 9.4 T are presented.

  20. Proton acceleration by 3D magnetic reconnection in solar flares

    NASA Astrophysics Data System (ADS)

    Browning, P. K.; Dalla, S.

    2007-05-01

    High energy charged particles are an important feature of solar activity such as flares, and indeed non thermal particles play a significant role in flare energy balance. Magnetic reconnection is the primary energy release mechanism in flares, and the strong DC electric fields associated with this reconnection may well be the origin of the high energy charged particles. Whilst particle acceleration has been widely studied for 2D configurations, little is known about 3D configurations. We investigate particle acceleration using a test particle approach, in the simplest 3D reconnection configuration, a 3D magnetic null point. Two modes of reconnection are possible: with a strong current filament along the "spine" field line connecting to the null, or with a sheet current at the "fan" plane of field lines emerging from the null. Using simple model fields, incorporating intiially only thee ideal reconnection region outside the current sheet (or filament), particle trajectories are investigated and the energy spectra and spatial distribution of accelerated particles are determined. We consider and compare fan and spine reconnection, and determine how the properties of the accelerated particles depend on the parameters of the reonnecting field. We also present preliminary results using more realistic, self consistent model fields.

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

    PubMed

    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.

  2. Monte Carlo simulation of single-plane magnetically focused narrow proton beams.

    PubMed

    McAuley, G A; Barnes, S R S; Slater, J M; Wroe, A J

    2013-02-07

    We present Monte Carlo simulations of magnetically focused proton beams shaped by a single quadrapole magnet. Such beams are narrowly focused in one longitudinal plane but fan out in the perpendicular plane producing elongated elliptical beam spots (a 'screwdriver' shape). The focused beams were compared to passively collimated beams (the current standard of delivery for small radiosurgery beams). Beam energies considered were relevant to functional radiosurgery and standard radiosurgery clinical applications. Three monoenergetic beams (100, 125, and 150 MeV) and a modulated beam were simulated. Monoenergetic magnetically focused beams demonstrated 28 to 32% lower entrance doses, 31 to 47% larger central peak to entrance depth dose ratios, 26 to 35% smaller integral dose, 25 to 32% smaller estimated therapeutic ratios, 19 to 37% smaller penumbra volumes, and 38 to 65% smaller vertical profile lateral penumbras at Bragg depth, compared to the collimated beams. Focused modulated beams showed 31% larger central peak to entrance dose ratio, and 62 to 65% smaller vertical lateral penumbras over the plateau of the spread out Bragg peak. These advantages can be attributed to the directional acceleration of protons in the transverse plane due to the magnetic field. Such beams can be produced using commercially available assemblies of permanent rare earth magnets that do not require electric power or cryrogenic cooling. Our simulations suggest that these magnets can be inexpensively incorporated into the beam line to deliver reduced dose to normal tissue, and enhanced dose to elongated elliptical targets with major and minor axes on the order of a few centimeters and millimeters, respectively. Such beams may find application in novel proton functional and standard radiosurgery treatments in and around critical structures.

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

    SciTech Connect

    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.

  4. Proton nuclear magnetic resonance of intact friend leukemia cells: phosphorylcholine increase during differentiation

    SciTech Connect

    Agris, P.F.; Campbell, I.D.

    1982-06-18

    Proton nuclear magnetic resonance of intact Friend leukemia cells was used to analyze their erythroid-like differentiation. The technique, which requires only 10/sup 8/ to 10/sup 9/ cells and approximately 2 minutes for acquisition of each spectrum, demonstrated the occurrence of many signal changes during differentiation. With cell extracts, 64 signals were assigned to 12 amino acids and 19 other intermediary metabolites, and a dramatic signal change was attributed to a fourfrease in cytoplasmic phosphorylcholines.

  5. Magnetism in C{sub 60} films induced by proton irradiation

    SciTech Connect

    Mathew, S.; Satpati, B.; Joseph, B.; Dev, B. N.; Nirmala, R.; Malik, S. K.; Kesavamoorthy, R.

    2007-02-15

    It is shown that polycrystalline fullerene thin films on hydrogen-passivated Si(111) substrates irradiated by 2 MeV protons display ferromagneticlike behavior at 5 K. At 300 K, both the pristine and the irradiated film show diamagnetic behavior. Magnetization data in the temperature range of 2-300 K in 1 T applied field, for the irradiated film show much stronger temperature dependence compared to the pristine film. Possible origins of ferromagneticlike signals in the irradiated films are discussed.

  6. Self-assembled arrays of polyoxometalate-based metal-organic nanotubes for proton conduction and magnetism.

    PubMed

    Jiao, Yan-Qing; Zang, Hong-Ying; Wang, Xin-Long; Zhou, En-Long; Song, Bai-Qiao; Wang, Chun-Gang; Shao, Kui-Zhan; Su, Zhong-Min

    2015-06-30

    The first polyoxometalate-based metal-organic nanotube constructed via covalent bonds has been synthesized. POM anions stick the metal-organic nanotubes to build 3D nanotubular arrays. The stability, magnetic and proton conducting properties are investigated.

  7. Magnetic moment of proton drip-line nucleus {sup 9}C

    SciTech Connect

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

    1994-10-01

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

  8. Measurement of pulsed-power-driven magnetic fields via proton deflectometry

    SciTech Connect

    Mariscal, D.; McGuffey, C.; Valenzuela, J.; Beg, F. N.; Wei, M. S.; Chittenden, J. P.; Niasse, N.; Presura, R.; Haque, S.; Wallace, M.; Arias, A.; Covington, A.; Sawada, H.; Wiewior, P.

    2014-12-01

    Measuring magnetic field and current distribution in Z-pinch plasma systems is crucial to the validation of Z-pinch theory. In this letter, the demonstration of proton deflectometry to pulsed-power-driven loads at the mega-amp scale is presented, which is capable of making more detailed field maps in high-density regions of plasmas. In this method, a laser-driven, broad-spectrum, MeV-energy proton beam is directed through a pulsed-power-driven plasma system, and the resulting deflections are measured to examine configuration of magnetic fields and to infer the currents that support them. The technique was first demonstrated on simple short-circuit loads, and the results are in excellent agreement with numerical simulations providing reliable estimates of the field and current configurations. It was then applied to a more complex—radial foil—plasma load. The measurements show unexpected proton deflections that exhibit the complexity of the plasma load and that with further analysis will reveal details about the current and magnetic field topology in this complex configuration.

  9. Ulysses observations of electron and proton components in a magnetic cloud and related wave activity

    NASA Technical Reports Server (NTRS)

    Osherovich, V. A.; Fainberg, J.; Stone, R. G.; MacDowall, R. J.; Phillips, J. L.; Balogh, A.

    1995-01-01

    In addition to a smooth rotation of the magnetic field vector, magnetic clouds have a low proton temperature T(sub p). Their expansion in the solar wind leads to depletion and therefore the ion component cools down. It has been shown recently that the electron component in magnetic clouds behaves differently: when the cloud expands, electron temperature Te anti correlates with density and therefore Te increases in the cloud, creating favorable conditions for the rise of ion-acoustic waves. For the magnetic cloud observed by Ulysses on June 10 - 12, 1993 at 4.64 AU at S 32.5 deg, we present observations for both electron and proton components and related plasma wave activity. Our results confirm the anti correlation between T(sub e) and electron density and also exhibit a high ratio of T(sub e)/T(sub P) in the cloud. Since Landau damping is not effective for T(sub e)/T(sub p) much greater than 1, Doppler shifted ion acoustic waves are expected in the cloud. Calculation of ion acoustic wave frequencies in the cloud and comparison with observed wave activity confirm this expectation. As in our previous work, we show that the electron component in the cloud obeys a polytropic law with gamma is less than 1 (gamma approximately equals 0.3-0.4). The dynamics of the magnetic cloud are determined to a large degree by the dominating electron pressure.

  10. Nuclear magnetic resonance proton imaging of bone pathology

    SciTech Connect

    Atlan, H.; Sigal, R.; Hadar, H.; Chisin, R.; Cohen, I.; Lanir, A.; Soudry, M.; Machtey, Y.; Schreiber, R.; Benmair, J.

    1986-02-01

    Thirty-two patients with diversified pathology were examined with a supraconductive NMR imager using spin echo with different TR and TE to obtain T1 and T2 weighted images. They included 20 tumors (12 primary, eight metastasis), six osteomyelitis, three fractures, two osteonecrosis, and one diffuse metabolic (Gaucher) disease. In all cases except for the stress fractures, the bone pathology was clearly visualized in spite of the normal lack of signal from the compact cortical bone. Nuclear magnetic resonance (NMR) imaging proved to be at least as sensitive as radionuclide scintigraphy but much more accurate than all other imaging procedures including computed tomography (CT) and angiography to assess the extension of the lesions, especially in tumors extended to soft tissue. This is due both to easy acquisition of sagittal and coronal sections and to different patterns of pathologic modifications of T1 and T2 which are beginning to be defined. It is hoped that more experience in clinical use of these patterns will help to discriminate between tumor extension and soft-tissue edema. We conclude that while radionuclide scintigraphy will probably remain the most sensitive and easy to perform screening test for bone pathology, NMR imaging, among noninvasive diagnostic procedures, appears to be at least as specific as CT. In addition, where the extension of the lesions is concerned, NMR imaging is much more informative than CT. In pathology of the spine, the easy visualization of the spinal cord should decrease the need for myelography.

  11. Proton magnetic resonance imaging using a nitrogen-vacancy spin sensor

    NASA Astrophysics Data System (ADS)

    Rugar, D.; Mamin, H. J.; Sherwood, M. H.; Kim, M.; Rettner, C. T.; Ohno, K.; Awschalom, D. D.

    2015-02-01

    Magnetic resonance imaging, with its ability to provide three-dimensional, elementally selective imaging without radiation damage, has had a revolutionary impact in many fields, especially medicine and the neurosciences. Although challenging, its extension to the nanometre scale could provide a powerful new tool for the nanosciences, especially if it can provide a means for non-destructively visualizing the full three-dimensional morphology of complex nanostructures, including biomolecules. To achieve this potential, innovative new detection strategies are required to overcome the severe sensitivity limitations of conventional inductive detection techniques. One successful example is magnetic resonance force microscopy, which has demonstrated three-dimensional imaging of proton NMR with resolution on the order of 10 nm, but with the requirement of operating at cryogenic temperatures. Nitrogen-vacancy (NV) centres in diamond offer an alternative detection strategy for nanoscale magnetic resonance imaging that is operable at room temperature. Here, we demonstrate two-dimensional imaging of 1H NMR from a polymer test sample using a single NV centre in diamond as the sensor. The NV centre detects the oscillating magnetic field from precessing protons as the sample is scanned past the NV centre. A spatial resolution of ˜12 nm is shown, limited primarily by the scan resolution.

  12. Irradiation effects on magnetic properties in neutron and proton irradiated reactor pressure vessel steel

    SciTech Connect

    Park, D.G.; Hong, J.H.; Kim, I.S.; Kim, H.C.

    1999-09-01

    The effects of neutron and proton dose on the magnetic properties of a reactor pressure vessel (RPV) steel were investigated. The coercivity and maximum induction increased in two stages with respect to neutron dose, being nearly constant up to a dose of 1.5 x 10{sup {minus}7} dpa, followed by a rapid increase up to a dose of 1.5 x 10{sup {minus}5} dpa. The coercivity and maximum induction in the proton irradiated specimens also showed a two stage variation with respect to proton dose, namely a rapid increase up to a dose of 0.2 x 10{sup {minus}2} dpa, then a decrease up to 1.2 x 10{sup {minus}2} dpa. The Barkhausen noise (BN) amplitude in neutron irradiated specimens also varied in two stages in a reverse manner, the transition at the same dose of 1.5 x 10{sup {minus}7} dpa. The BN amplitude in proton irradiated specimens decreased by 60% up to 0.2 x 10{sup {minus}2} dpa followed by an increase up to 1.2 x 10{sup {minus}2} dpa. The results were in good accord with the one dimensional domain wall model considering the density of defects and wall energy.

  13. A Nested Phosphorus and Proton Coil Array for Brain Magnetic Resonance Imaging and Spectroscopy

    PubMed Central

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

    2015-01-01

    A dual-nuclei radiofrequency coil array was constructed for phosphorus and proton magnetic resonance imaging and spectroscopy of the human brain at 7 Tesla. 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 1.4 cm nominal isotropic resolution in 15 min (2.3 cm actual resolution), while additionally enabling 1 mm 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. PMID:26375209

  14. Modeling the inner plasma sheet protons and magnetic field under enhanced convection

    NASA Astrophysics Data System (ADS)

    Wang, Chih-Ping; Lyons, Larry R.; Chen, Margaret W.; Wolf, Richard A.; Toffoletto, Frank R.

    2003-02-01

    In order to understand the evolution of the protons and magnetic field in the inner plasma sheet from quiet to disturbed conditions, we incorporate a modified version of the Magnetospheric Specification Model (MSM) with a modified version of the Tsyganenko 96 (T96) magnetic field model to simulate the protons and magnetic field under an increasing convection electric field with two-dimensional (2-D) force balance maintained along the midnight meridian. The local time dependent proton differential fluxes assigned to the model boundary are a mixture of hot plasma from the mantle and cooler plasma from the low latitude boundary layer (LLBL). We previously used this model to simulate the inner plasma sheet under weak convection corresponding to a cross polar cap potential drop (ΔΦPC) equal to 26 kV and obtained 2-D quiet time equilibrium for proton and magnetic field that agrees well with observations. We start our simulation for enhanced convection with this quiet time equilibrium and time-independent boundary particle sources and increase ΔΦPC steadily from 26 to 146 kV in 5 hours. Simulations are also run separately to steady states by keeping ΔΦPC constant after it is increased to 98 and 146 kV. The magnitudes of proton pressure, number density, and temperature and their increase from quiet to moderate activity (ΔΦPC = 98 kV) are consistent with most observations. Our simulation at high activity (ΔΦPC = 146 kV) underestimates the observed pressure and temperature. This disagreement indicates possible dependence of the boundary particle sources on activity and possible effects of solar wind dynamic pressure enhancements that have not yet been included in our simulation. The simulated equatorial pressures and temperatures show stronger enhancement on the dusk side than on the dawn side as convection is increased, while density profiles show an increase on the dawn side and a decrease on the dusk side. The simulated proton flow speed at the equatorial plane

  15. In vivo1H NMR spectroscopy of the human brain at 9.4 T: Initial results

    NASA Astrophysics Data System (ADS)

    Deelchand, Dinesh Kumar; Moortele, Pierre-François Van de; Adriany, Gregor; Iltis, Isabelle; Andersen, Peter; Strupp, John P.; Thomas Vaughan, J.; Uğurbil, Kâmil; Henry, Pierre-Gilles

    2010-09-01

    In vivo proton NMR spectroscopy allows non-invasive detection and quantification of a wide range of biochemical compounds in the brain. Higher field strength is generally considered advantageous for spectroscopy due to increased signal-to-noise and increased spectral dispersion. So far 1H NMR spectra have been reported in the human brain up to 7 T. In this study we show that excellent quality short echo time STEAM and LASER 1H NMR spectra can be measured in the human brain at 9.4 T. The information content of the human brain spectra appears very similar to that measured in the past decade in rodent brains at the same field strength, in spite of broader linewidth in human brain. Compared to lower fields, the T1 relaxation times of metabolites were slightly longer while T2 relaxation values of metabolites were shorter (<100 ms) at 9.4 T. The linewidth of the total creatine (tCr) resonance at 3.03 ppm increased linearly with magnetic field (1.35 Hz/T from 1.5 T to 9.4 T), with a minimum achievable tCr linewidth of around 12.5 Hz at 9.4 T. At very high field, B0 microsusceptibility effects are the main contributor to the minimum achievable linewidth.

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

    NASA Technical Reports Server (NTRS)

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

    NASA Astrophysics Data System (ADS)

    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.

  18. Initial test results of the Los Alamos proton-storage-ring bump-magnet system

    SciTech Connect

    Rose, C.R.; Barlow, D.B.; Redd, D.B.

    1997-09-01

    An upgrade program for increasing the stored beam current in the LANSCE Proton Storage is presently under way. Part of the upgrade effort has been to design, specify, and add four bump-magnet/modulator systems to the ring. This paper describes the initial test results of the first bump-magnet/modulator system. The paper begins with an overview of the pulsed-power system including important specifications of the modulator, magnet, cabling, and control system. In the main portion of the paper, waveforms and test data are included showing the accuracy, repeatability, and stability of the magnet-current pulses. These magnet pulses are programmable both in rise and fall time as well as in amplitude. The amplitude can be set between 50 and 300 A, the rise-time is fixed at 1 ms, and the linear fall-time can be varied between 500 {mu}s and 1500 {mu}s. Other issues such as loading effects and power dissipation in the magnet-bore beamtube are examined and reported.

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

    SciTech Connect

    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 $G_M^s=-0.034 \\pm 0.021$ $\\mu_N$.

  20. Internal field of homogeneously magnetized toroid sensor for proton free precession magnetometer

    NASA Astrophysics Data System (ADS)

    Primdahl, F.; Merayo, J. M. G.; Brauer, P.; Laursen, I.; Risbo, T.

    2005-02-01

    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 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 nT.

  1. Analyzing power in pion-proton bremsstrahlung, and the. Delta. sup ++ (1232) magnetic moment

    SciTech Connect

    Bosshard, A.; Amsler, C.; Doebeli, M.; Doser, M.; Schaad, M.; Riedlberger, J.; Truoel, P. ); Bistirlich, J.A.; Crowe, K.M.; Ljungfelt, S.; Meyer, C.A. ); van den Brandt, B.; Konter, J.A.; Mango, S.; Renker, D. ); Loude, J.F.; Perroud, J.P. ); Haddock, R.P. ); Sober, D.I. )

    1991-10-01

    We report on a first measurement of the polarized-target asymmetry of the pion-proton bremsstrahlung cross section ({pi}{sup +}{ital p}{r arrow}{pi}{sup {minus}}{ital p}{gamma}). As in previous cross section measurements the pion energy (298 MeV) and the detector geometry for this experiment was chosen to optimize the sensitivity to the radiation from the magnetic dipole moment of the {Delta}{sup ++}(1232) resonance {mu}{sub {Delta}}. Comparison to a recent isobar model for pion-nucleon bremsstrahlung yields {mu}{sub {Delta}}=(1.62{plus minus}0.18){mu}{sub {ital p}}, where {mu}{sub {ital p}} is the proton magnetic moment. Since the asymmetry depends less than the cross section on the choice of the other input parameters for the model, their uncertainties affect this analysis by less than the experimental error. However the theory fails to represent both the cross section and the asymmetry data at the highest photon energies. Hence further improvements in the calculations are needed before the model dependence of the magnetic moment analysis can be fully assessed. The present result agrees with bag-model corrections to the SU(6) prediction {mu}{sub {Delta}}=2{mu}{sub {ital p}}. As a by-product, the analyzing power for elastic {pi}{sup +}{ital p} scattering at 415 MeV/{ital c} was also measured. This second result is in good agreement with phase shift calculations.

  2. Magnetic dipole moment of the doubly-closed-shell plus one proton nucleus 49Sc.

    PubMed

    Ohtsubo, T; Stone, N J; Stone, J R; Towner, I S; Bingham, C R; Gaulard, C; Köster, U; Muto, S; Nikolov, J; Nishimura, K; Simpson, G S; Soti, G; Veskovic, M; Walters, W B; Wauters, F

    2012-07-20

    The nucleus 49Sc, having a single f(7/2) proton outside doubly magic 48Ca (Z=20, N=28), is one of the very few isotopes which makes possible testing of the fundamental theory of nuclear magnetism. The magnetic moment has been measured by online β NMR of nuclei oriented at milli-Kelvin temperatures to be (+)5.616(25)  μ(N). The result is discussed in terms of a detailed theory of the structure of the magnetic moment operator, showing excellent agreement with calculated departure from the f(7/2) Schmidt limit extreme single-particle value. The measurement completes the sequence of moments of Sc isotopes with even numbers of f(7/2) neutrons: the first such isotopic chain between two major shells for which a full set of moment measurements exists. The result further completes the isotonic sequence of ground-state moments of nuclei with an odd number of f(7/2) protons coupled to a closed subshell of f(7/2) neutrons. Comparison with a recent shell-model calculation of the latter sequence is made.

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

    PubMed

    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.

  4. Phosphorus and proton magnetic resonance spectroscopy demonstrates mitochondrial dysfunction in early and advanced Parkinson's disease.

    PubMed

    Hattingen, Elke; Magerkurth, Jörg; Pilatus, Ulrich; Mozer, Anne; Seifried, Carola; Steinmetz, Helmuth; Zanella, Friedhelm; Hilker, Rüdiger

    2009-12-01

    Mitochondrial dysfunction hypothetically contributes to neuronal degeneration in patients with Parkinson's disease. While several in vitro data exist, the measurement of cerebral mitochondrial dysfunction in living patients with Parkinson's disease is challenging. Anatomical magnetic resonance imaging combined with phosphorus and proton magnetic resonance spectroscopic imaging provides information about the functional integrity of mitochondria in specific brain areas. We measured partial volume corrected concentrations of low-energy metabolites and high-energy phosphates with sufficient resolution to focus on pathology related target areas in Parkinson's disease. Combined phosphorus and proton magnetic resonance spectroscopic imaging in the mesostriatal region was performed in 16 early and 13 advanced patients with Parkinson's disease and compared to 19 age-matched controls at 3 Tesla. In the putamen and midbrain of both Parkinson's disease groups, we found a bilateral reduction of high-energy phosphates such as adenosine triphophosphate and phosphocreatine as final acceptors of energy from mitochondrial oxidative phosphorylation. In contrast, low-energy metabolites such as adenosine diphophosphate and inorganic phosphate were within normal ranges. These results provide strong in vivo evidence that mitochondrial dysfunction of mesostriatal neurons is a central and persistent phenomenon in the pathogenesis cascade of Parkinson's disease which occurs early in the course of the disease.

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

    PubMed

    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 < 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

    NASA Astrophysics Data System (ADS)

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

    NASA Astrophysics Data System (ADS)

    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.

  8. [Conventional and diffusion-weighted magnetic resonance imaging and proton spectroscopy in MELAS].

    PubMed

    Casimiro, Carlos; Martins, Joana; Nunes, César; Parreira, Tiago; Batista, Sónia; Cordeiro, Miguel; Matias, Fernando; Rebelo, Olinda; Freitas, Pedro

    2012-01-01

    MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) is a mitochondrial hereditary dysfunction in which the physiopathological mechanism of cerebral lesions is not totally understood as yet. Typically, these lesions are described as having normal to increased apparent diffusion coefficient (ADC), and this has been used to distinguish stroke-like lesions from ischemic lesions. Notwithstanding this, within the last few years, there have been reports of diffusion restriction in stroke-like episodes. Analysis of the diffusion characteristics on serial magnetic resonance imaging (MRI) over a 16 month period, on a patient with MELAS and stroke-like lesions, to investigate the controversial changes of the ADC, reported in the last years. Evaluation of the proton spectroscopy changes in stroke-like lesions and apparently spared brain. We performed four serial magnetic resonance imaging (MRI), including two stroke-like episodes, in a 28-year-old man with MELAS (mitochondrial DNA mutation A3243G). Qualitative analysis of the magnetic resonance images, including the single voxel spectroscopy and ADC maps, with analysis of evolution patterns of the last ones. Both MRI that were performed during those episodes of stroke-like lesion revealed areas of diffusion restriction, coexisting areas of high ADC. During the chronic phase, there was a regression of those changes. Proton spectroscopy showed the presence of lactate and reduction of N-acetyl aspartate peak in stroke-like lesion and the presence of lactate in apparently spared brain. All alterations that were recorded strengthen the view that cytotoxic oedema can occur in stroke-like lesions. Thus, their presence should not weaken the possibility of MELAS, especially if those lesions affect the temporal, parietal and/or occipital lobes, or if they predominantly involve the cortical gray matter, spanning vascular borders and if proton spectroscopy reveals lactate peak in the apparently spared brain.

  9. Proton nuclear magnetic resonance study of hirudin: resonance assignment and secondary structure

    SciTech Connect

    Sukumaran, D.K.; Clore, G.M.; Preuss, A.; Zarbock, J.; Gronenbron, A.M.

    1987-01-27

    The /sup 1/H NMR spectrum of the 65-residue protein hirudin is assigned in a sequential manner by using a combination of two-dimensional nuclear magnetic resonance techniques to demonstrate through-bond and through space (<5-A) connectives. The secondary structure of hirudin is deduced from a qualitative interpretation of the nuclear Overhauser effects involving the backbone NH, C/sup ..cap alpha../H, and C/sup ..beta../H protons. It is shown that hirudin has two ..beta..-sheets and no ..cap alpha..-helices.

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

    SciTech Connect

    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. High-resolution proton nuclear magnetic resonance characterization of seminolipid from bovine spermatozoa.

    PubMed

    Alvarez, J G; Storey, B T; Hemling, M L; Grob, R L

    1990-06-01

    The high-resolution one- and two-dimensional proton nuclear magnetic resonance (1H-NMR) characterization of seminolipid from bovine spermatozoa is presented. The 1H-NMR data was confirmed by gas-liquid chromatography-mass spectrometric analysis of the partially methylated alditol acetates of the sugar unit, mild alkaline methanolysis of the glyceryl ester, mobility on normal phase and diphasic thin-layer chromatography (HPTLC), and fast atom bombardment mass spectrometry (FAB-MS). The structure of the molecule corresponds to 1-O-hexadecyl-2-O-hexadecanoyl-3-O-beta-D-(3'-sulfo)-galactopyranosyl- sn-glycerol.

  12. Ion hydration effects in aqueous solutions of strong electrolytes, according to proton magnetic relaxation measurements

    NASA Astrophysics Data System (ADS)

    Melnichenko, N. A.

    2014-12-01

    The concentration dependences of proton magnetic relaxation (PMR) rates measured at different temperatures in aqueous electrolyte solutions and concentrated seawater (SW) in a wide range of salt concentrations and for different seawater salinities are presented, along with the concentration dependences of PMR rates determined in salts dissolved directly in seawater. The coordination numbers of the basic ions in seawater were determined from the complete solvation limits and compared with those measured in single-component water-salt solutions. The attaining of complete solvation limits was determined using the PMR data for ions of different hydration signs.

  13. [Quantitative determination of bosentan by proton nuclear magnetic resonance with internal standard method].

    PubMed

    Zhang, Cai-Yu; Zhang, Na; He, Lan

    2014-02-01

    The study aims to establish a quantitative nuclear magnetic resonance (QNMR) method for the determination of the absolute content of bosentan. Proton nuclear magnetic resonance spectroscopy [1H NMR] spectra were obtained in CDCl3 with the internal standard dimethyl terephthalate and zg30 pulse sequence by using a Bruker AVANCE II 400 spectrometer. The content of bosentan is determined with QNMR in comparison with the result obtained by mass balance method. The result is 96.25% by QNMR and 96.54% by mass balance method. A rapid and accurate QNMR method has been established for the quantitative determination of the absolute content of bosentan. The study provides a new way for the quality control and calibration of a new reference standard material, it could be the complementary with the mass balance method for the assay of standard reference.

  14. Non-destructive ripeness sensing by using proton NMR (Nuclear Magnetic Resonance)

    SciTech Connect

    Cho, Seong In; Krutz, G.W.; Stroshine, R.L. . Dept. of Agricultural Engineering); Bellon, V. , 34 - Montpellier )

    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). 7 refs., 4 figs.

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

    DOE R&D Accomplishments Database

    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).

  16. Quantifying solid-fluid interfacial phenomena in porous rocks with proton nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Schmidt, Ehud J.; Velasco, Katherine K.; Nur, Amos M.

    1986-04-01

    The three order-of-magnitude variation in the proton nuclear magnetic resonance (NMR) longitudinal relaxation time T1 of water adsorbed on silica surfaces versus that of bulk water makes proton NMR studies of porous materials powerful tools to study the effects of adsorption. Recent theory permits the utilization of this different response to obtain pore space surface-to-volume (S/V) distribution functions by inverting the decay of the z component of magnetization of fully saturated porous rocks; information can likewise be obtained on the fluid distribution at partially saturated conditions. A computer program has been developed to invert the NMR relaxation curves for the S/V distribution function, assuming an isolated pore regime, the ramifications of which are examined. The program has been applied to experimental results from water, porous sandstones, and tight gas sands at various pore fluid saturations and varying electrolyte content. For the fully saturated case, the results show promise in the application of NMR to describing pore space geometries in rock samples with widely varying surface-to-volume ratios. For partially saturated rocks, the results reflect the preferential early draining of the large pores at high water saturations, connectivity percolation phenomena at intermediate saturations, and the dominating role of adsorbed water films at low water saturations. Experiments on rocks saturated with saline solutions disclose the importance of the effects of alteration of the active sites on the rock surfaces as well as the role of electrolytes in modifying the structural properties of bulk solution.

  17. Proton and deuteron nuclear magnetic resonance studies of amorphous hydrogenated silicon, carbon, and carbon alloys

    NASA Astrophysics Data System (ADS)

    Kernan, Mary Jane Wurth

    Despite the profound influence of semiconductors and the changes they have produced, many fundamental questions remain unanswered. We have used proton and deuteron nuclear magnetic resonance (NMR) to explore the role of hydrogens in amorphous silicon and amorphous carbon and carbon alloy films. In the carbon films, dipolar filtering techniques reveal a two-component shifted lineshape in the proton NMR spectra and deuteron magnetic resonance (DMR) data demonstrate a feedstock gas dependence in the film deposition process. In these measurements, DMR is used to examine the effect of hydrogen on the photovoltaic properties of amorphous silicon thin films. We have measured the effects of photoillumination on amorphous silicon, particularly with respect to the process of metastable defect formation (the Staebler-Wronski effect). The creation and passivation of dangling silicon bonds is observed and quantified. We report large-scale light-induced atomic rearrangements which produce shifts and broadenings of the DMR lineshapes. The deuterium NMR lineshape component most affected by atomic rearrangements is a broad central feature which is shown to be molecular in origin. This spectral feature includes hydrogens trapped and immobile on surfaces created by strains and dislocations in the material. Narrowing of the lineshape at elevated temperatures indicates motion with a small activation energy. The substantial population represented by this feature is shown to account for at least 15% of the total hydrogens in high-quality amorphous silicon samples.

  18. Proton Magnetic Form Factor from Existing Elastic e-p Cross Section Data

    NASA Astrophysics Data System (ADS)

    Ou, Longwu; Christy, Eric; Gilad, Shalev; Keppel, Cynthia; Schmookler, Barak; Wojtsekhowski, Bogdan

    2015-04-01

    The proton magnetic form factor GMp, in addition to being an important benchmark for all cross section measurements in hadron physics, provides critical information on proton structure. Extraction of GMp from e-p cross section data is complicated by two-photon exchange (TPE) effects, where available calculations still have large theoretical uncertainties. Studies of TPE contributions to e-p scattering have observed no nonlinear effects in Rosenbluth separations. Recent theoretical investigations show that the TPE correction goes to 0 when ɛ approaches 1, where ɛ is the virtual photon polarization parameter. In this talk, existing e-p elastic cross section data are reanalyzed by extrapolating the reduced cross section for ɛ approaching 1. Existing polarization transfer data, which is supposed to be relatively immune to TPE effects, are used to produce a ratio of electric and magnetic form factors. The extrapolated reduced cross section and polarization transfer ratio are then used to calculate GEp and GMp at different Q2 values.

  19. Double-proton beams and magnetic switchbacks in the solar wind

    NASA Astrophysics Data System (ADS)

    Neugebauer, Marcia; Goldstein, Bruce E.

    2013-06-01

    Previous work has led to suggestions that core-beam distributions of ions in the fast polar solar wind could be caused either by wave-particle interactions in interplanetary space or by ejections of faster material into pre-existing flows. It has also been suggested that the many-hour-long high-speed structures, or microstreams, in the polar wind could be the interplanetary manifestation of solar X-ray jets observed in supergranule boundaries. Proton distribution functions both in the microstreams and in the ambient fast polar wind are examined to test the conjecture that solar ejections may play an important role in creating double proton beams. Double-peaked distributions in the microstreams that have the peak containing most of the particles (the core) being faster than the less-dense beam are suggestive of ejection of material that may have come from a jet. It is concluded, however, that those "backwards" distributions were caused by magnetic reversals, or switchbacks, rather than by the inclusion of faster material. Other than in the switchbacks, there is no qualitative difference between the double-proton streaming in the microstreams peaks and in the ambient wind. Evidence is provided that essentially all departures of the magnetic field from the dominant polarity of the polar wind are due to such switchbacks rather than to solar fields with non-dominant polarities. It is also shown that, in the fast polar solar wind, there are more short-duration switchbacks than longer ones and that the incidence of reversed fields increases with solar distance.

  20. SUPERCONDUCTING MAGNET SYSTEM AT THE 50 GEV PROTON BEAM LINE FOR THE J-PARC NEUTRINO EXPERIMENT.

    SciTech Connect

    WANDERER,P.; ET AL.

    2003-06-15

    A neutrino oscillation experiment using the J-PARC SO GeV 0.75 MW proton beam is planned as a successor to the K2K project currently being operated at KEK. A superconducting magnet system is required for the arc section of the primary proton beam line to be within the space available at the site. A system with 28 combined function magnets is proposed to simplify the system and optimize the cost. The required fields for the magnets are 2.6 T dipole and 19 T/m quadrupole. The magnets are also required to have a large aperture, 173.4 mm diameter, to accommodate the large beam emittance. The magnets will be protected by cold diodes and cooled by forced flow supercritical helium produced by a 4.5 K, 2 {approx} 2.5 kW refrigerator. This paper reports the system overview and the design status.

  1. Transporters for Antiretroviral Drugs in Colorectal CD4+ T Cells and Circulating α4β7 Integrin CD4+ T Cells: Implications for HIV Microbicides.

    PubMed

    Mukhopadhya, Indrani; Murray, Graeme I; Duncan, Linda; Yuecel, Raif; Shattock, Robin; Kelly, Charles; Iannelli, Francesco; Pozzi, Gianni; El-Omar, Emad M; Hold, Georgina L; Hijazi, Karolin

    2016-09-06

    CD4+ T lymphocytes in the colorectal mucosa are key in HIV-1 transmission and dissemination. As such they are also the primary target for antiretroviral (ARV)-based rectal microbicides for pre-exposure prophylaxis. Drug transporters expressed in mucosal CD4+ T cells determine ARV distribution across the cell membrane and, most likely, efficacy of microbicides. We describe transporters for antiretroviral drugs in colorectal mucosal CD4+ T lymphocytes and compare gene expression with circulating α4β7+CD4+ T cells, which traffic to the intestine and have been shown to be preferentially infected by HIV-1. Purified total CD4+ T cells were obtained from colorectal tissue and blood samples by magnetic separation. CD4+ T cells expressing α4β7 integrin were isolated by fluorescence-activated cell sorting from peripheral blood mononuclear cells of healthy volunteers. Expressions of 15 efflux and uptake drug transporter genes were quantified using Taqman qPCR assays. Expression of efflux transporters MRP3, MRP5, and BCRP and uptake transporter CNT2 were significantly higher in colorectal CD4+ T cells compared to circulating CD4+ T cells (p = 0.01-0.03). Conversely, circulating α4β7+CD4+ T cells demonstrated significantly higher expression of OATPD compared to colorectal CD4+ T cells (p = 0.001). To the best of our knowledge this is the first report of drug transporter gene expression in colorectal CD4+ and peripheral α4β7+CD4+ T cells. The qualitative and quantitative differences in drug transporter gene expression profiles between α4β7+CD4+ T cells and total mucosal CD4+ T cells may have significant implications for the efficacy of rectally delivered ARV-microbicides. Most notably, we have identified efflux drug transporters that could be targeted by selective inhibitors or beneficial drug-drug interactions to enhance intracellular accumulation of antiretroviral drugs.

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

    PubMed

    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.

  3. {sup 1}H and {sup 31}P nuclear magnetic resonance study of proton-irradiated KH{sub 2}PO{sub 4}

    SciTech Connect

    Kim, Se-Hun; Lee, Kyu Won; Oh, B. H.; Lee, Cheol Eui; Hong, K. S.

    2007-11-01

    We have studied the microscopic structure and dynamics in a proton-irradiated KH{sub 2}PO{sub 4} single crystal. Our {sup 1}H and {sup 31}P nuclear magnetic resonance measurements indicate that proton irradiation gives rise to a decrease in the local dipolar order of the rigid lattice protons and an increase in interstitial protons as well as structural distortion of the PO{sub 4} tetrahedra.

  4. Utility of cerebral proton magnetic resonance spectroscopy in differential diagnosis of HIV-related dementia.

    PubMed

    Swindells, S; McConnell, J R; McComb, R D; Gendelman, H E

    1995-09-01

    Opportunistic infections often coexist with human immunodeficiency virus (HIV) infection in brain. Making the correct diagnosis is often difficult despite recent advances in neuroimaging techniques. 1H magnetic resonance spectroscopy (1H MRS) is an emerging non-invasive examination for diagnosis and monitoring of brain disorders. 1H MRS measures a variety of organic compounds using magnetism and radio waves. Biochemical aberrations in brain, not shown by conventional tests, may be demonstrated by 1H MRS testing. A patient coinfected with HIV and hepatitis B (HBV) presented with progressive dementia. Clinical, neuroradiological and cerebrospinal fluid (CSF) examinations failed to provide a diagnosis in support of either HIV-1-associated cognitive/motor complex or HBV-induced hepatic encephalopathy (HE), 1H MRS was used in an attempt to discriminate between these diagnoses. Spectroscopy demonstrated increased glutamine and normal N-acetyl aspartate (NAA) levels, metabolic changes consistent with HE. These findings were later confirmed pathologically. Proton magnetic resonance spectroscopy is a non-invasive test with utility for the differential diagnosis of HIV-associated dementia.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    Sjue, S. K. L. Mariam, F. G.; Merrill, F. E.; Morris, C. L.; Saunders, A.

    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.

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

    NASA Astrophysics Data System (ADS)

    Sjue, S. K. L.; Mariam, F. G.; Merrill, F. E.; Morris, C. L.; Saunders, A.

    2016-01-01

    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.

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

    PubMed

    Sjue, S K L; Mariam, F G; Merrill, F E; Morris, C L; Saunders, A

    2016-01-01

    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.

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

    PubMed

    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.

  11. Metabolic assessment of the human pons by in vivo proton magnetic resonance spectroscopy.

    PubMed

    Guan, Ji-Tian; Xu, Xiao-Hu; Geng, Yi-Qun; Yu, Xiao-Jun; Wu, Ren-Hua

    2008-08-28

    To determine the normal mean reference normal value for metabolic ratios in the pons of healthy adult Chinese subjects by using proton magnetic resonance spectroscopy (1HMRS). Eighty healthy Chinese subjects, ranging in age from 21 to 60 years, were divided into four groups, each containing 20 subjects per decade. The pons of every subject was scanned on single-voxel 1HMRS by using the point-resolved proton spectroscopy sequence (PRESS) with echo time (TE)=144 ms and repetition time (TR)=1500 ms. The total mean ratios of N-acetylasparate/creatine-phosphocreatine (NAA/Cr), NAA/choline-containing compounds (Cho) and Cho/Cr in subjects ranging from 21 to 60 years were 2.13+/-0.07, 1.22+/-0.11 and 1.81+/-0.09 respectively. The highest metabolite ratios were seen in the 41-50 year group. There was no significant difference with respect to age or gender. The ratios of NAA/Cr, NAA/Cho or Cho/Cr in the pons did not correlate with the age or gender of healthy subjects.

  12. A proton magnetic resonance spectroscopic study in autism spectrum disorders: amygdala and orbito-frontal cortex.

    PubMed

    Mori, Kenji; Toda, Yoshihiro; Ito, Hiromichi; Mori, Tatsuo; Goji, Aya; Fujii, Emiko; Miyazaki, Masahito; Harada, Masafumi; Kagami, Shoji

    2013-02-01

    We previously reported neural dysfunction in the anterior cingulate cortex and dorsolateral prefrontal cortex in autistic patients using proton magnetic resonance spectroscopy ((1)H-MRS). In this investigation, we measured chemical metabolites in the left amygdala and the bilateral orbito-frontal cortex (OFC), which are the main components of the social brain. We also examined the association between these metabolic findings and social abilities in subjects with autism. The study group included 77 autistic patients (3-6years old; mean age 4.1; 57 boys and 20 girls). The control subjects were 31 children (3-6years old; mean age 4.0; 23 boys and 8 girls). Conventional proton MR spectra were obtained using the STEAM sequence with parameters of TR=5 sec and TE=15 msec by a 1.5-tesla clinical MRI system. We analyzed the concentrations of N-acetylaspartate (NAA), creatine/phosphocreatine (Cr), and choline-containing compounds (Cho) using LCModel (Ver. 6.1). The concentrations of NAA in the left amygdala and the bilateral OFC in autistic patients were significantly decreased compared to those in the control group. In the autistic patients, the NAA concentrations in these regions correlated with their social quotient. These findings suggest the presence of neuronal dysfunction in the amygdala and OFC in autism. Dysfunction in the amygdala and OFC may contribute to the pathogenesis of autism.

  13. Metabolic Profiling of Dividing Cells in Live Rodent Brain by Proton Magnetic Resonance Spectroscopy (1HMRS) and LCModel Analysis

    PubMed Central

    Park, June-Hee; Lee, Hedok; Makaryus, Rany; Yu, Mei; Smith, S. David; Sayed, Kasim; Feng, Tian; Holland, Eric; Van der Linden, Annemie; Bolwig, Tom G.; Enikolopov, Grigori; Benveniste, Helene

    2014-01-01

    Rationale Dividing cells can be detected in the live brain by positron emission tomography or optical imaging. Here we apply proton magnetic resonance spectroscopy (1HMRS) and a widely used spectral fitting algorithm to characterize the effect of increased neurogenesis after electroconvulsive shock in the live rodent brain via spectral signatures representing mobile lipids resonating at ∼1.30 ppm. In addition, we also apply the same 1HMRS methodology to metabolically profile glioblastomas with actively dividing cells growing in RCAS-PDGF mice. Methods 1HMRS metabolic profiles were acquired on a 9.4T MRI instrument in combination with LCModel spectral analysis of: 1) rat brains before and after ECS or sham treatments and 2) RCAS-PDGF mice with glioblastomas and wild-type controls. Quantified 1HMRS data were compared to post-mortem histology. Results Dividing cells in the rat hippocampus increased ∼3-fold after ECS compared to sham treatment. Quantification of hippocampal metabolites revealed significant decreases in N-acetyl-aspartate but no evidence of an elevated signal at ∼1.3 ppm (Lip13a+Lip13b) in the ECS compared to the sham group. In RCAS-PDGF mice a high density (22%) of dividing cells characterized glioblastomas. Nile Red staining revealed a small fraction (3%) of dying cells with intracellular lipid droplets in the tumors of RCAS-PDGF mice. Concentrations of NAA were lower, whereas lactate and Lip13a+Lip13b were found to be significantly higher in glioblastomas of RCAS-PDGF mice, when compared to normal brain tissue in the control mice. Conclusions Metabolic profiling using 1HMRS in combination with LCModel analysis did not reveal correlation between Lip13a+Lip13b spectral signatures and an increase in neurogenesis in adult rat hippocampus after ECS. However, increases in Lip13a+Lip13b were evident in glioblastomas suggesting that a higher density of actively dividing cells and/or the presence of lipid droplets is necessary for LCModel to reveal

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

    PubMed

    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 nuclear magnetic resonance characterization of resins from the family pinaceae.

    PubMed

    Lambert, Joseph B; Kozminski, Michael A; Fahlstrom, Carl A; Santiago-Blay, Jorge A

    2007-02-01

    Proton magnetic resonance spectra were recorded for solutions of resinous materials harvested from 82 species in seven genera of the gymnospermous plant family Pinaceae. Data were recorded in both one and two (COSY) dimensions. Approximately 11 peaks in the 1D spectra and 10 cross-peaks in the 2D spectra were present in almost all pinacean spectra, providing a familial diagnostic. Some 40 1D peaks or peak clusters and 60 2D cross-peaks or clusters were considered significant and are reported, when present, for all species. Whereas previous solid-state 13C data were diagnostic primarily at the family level, the patterns of 1D and 2D peaks may provide diagnostic information at the genus and species levels. These spectra constitute the first broad use of 1H NMR to study plant exudates in general and to provide taxonomic characterization in particular.

  16. [A new method of distinguishing weak and overlapping signals of proton magnetic resonance spectroscopy].

    PubMed

    Jiang, Gang; Quan, Hong; Wang, Cheng; Gong, Qiyong

    2012-12-01

    In this paper, a new method of combining translation invariant (TI) and wavelet-threshold (WT) algorithm to distinguish weak and overlapping signals of proton magnetic resonance spectroscopy (1H-MRS) is presented. First, the 1H-MRS spectrum signal is transformed into wavelet domain and then its wavelet coefficients are obtained. Then, the TI method and WT method are applied to detect the weak signals overlapped by the strong ones. Through the analysis of the simulation data, we can see that both frequency and amplitude information of small-signals can be obtained accurately by the algorithm, and through the combination with the method of signal fitting, quantitative calculation of the area under weak signals peaks can be realized.

  17. Correction of Proton Resonance Frequency Shift Temperature Maps for Magnetic Field Disturbances Caused by Breathing

    NASA Astrophysics Data System (ADS)

    Shmatukha, Andriy V.; Bakker, Chris J. G.

    2006-05-01

    Respiratory Induced Resonance Offset (RIRO) is a periodic disturbance of the magnetic field due to breathing. Such disturbances handicap the accuracy of the Proton Resonance Frequency Shift (PRFS) method of MRI temperature mapping in anatomies situated nearby the lungs and chest wall. In this work, we propose a method capable of minimizing errors caused by RIRO in PRFS temperature maps. In this method, a set of baseline images characterizing RIRO at a variety of respiratory cycle instants is acquired before the thermal treatment starts. During the treatment, the temperature evolution is found from two successive images. Then, the calculated temperature changes are corrected for the additional contribution caused by RIRO using the pre-treatment baseline images acquired at the identical instances of the respiratory cycle. Our method is shown to improve the accuracy and stability of PRFS temperature maps in the presence of RIRO and motion in phantom and volunteer experiments.

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

    PubMed

    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.

  19. Use of proton magnetic resonance spectroscopy in the treatment of psychiatric disorders: a critical update.

    PubMed

    Bustillo, Juan R

    2013-09-01

    Because of the wide availability of hardware as well as of standardized analytic quantification tools, proton magnetic resonance spectroscopy ((1)H-MRS) has become widely used to study psychiatric disorders. (1)H-MRS allows measurement of brain concentrations of more traditional singlet neurometabolites like N-acetylaspartate, choline, and creatine. More recently, quantification of the more complex multiplet spectra for glutamate, glutamine, inositol, and γ-aminobutyric acid have also been implemented. Here we review applications of (1)H-MRS in terms of informing treatment options in schizophrenia, bipolar disorder, and major depressive disorders. We first discuss recent meta-analytic studies reporting the most reliable findings. Then we evaluate the more sparse literature focused on 1H-MRS-detected neurometabolic effects of various treatment approaches in psychiatric populations. Finally we speculate on future developments that may result in translation of these tools to improve the treatment of psychiatric disorders.

  20. In vivo proton magnetic resonance spectroscopy of breast cancer: a review of the literature

    PubMed Central

    2012-01-01

    An emerging clinical modality called proton magnetic resonance spectroscopy (1H-MRS) enables the non-invasive in vivo assessment of tissue metabolism and is demonstrating applications in improving the specificity of MR breast lesion diagnosis and monitoring tumour responsiveness to neoadjuvant chemotherapies. Variations in the concentration of choline-based cellular metabolites, detectable with 1H-MRS, have shown an association with malignant transformation of tissue in in vivo and in vitro studies. 1H-MRS exists as an adjunct to the current routine clinical breast MR examination. This review serves as an introduction to the field of breast 1H-MRS, discusses modern high-field strength and quantitative approaches and technical considerations, and reviews the literature with respect to the application of 1H-MRS for breast cancer. PMID:22515594

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

    PubMed

    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.

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

    ERIC Educational Resources Information Center

    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…

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

    ERIC Educational Resources Information Center

    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…

  4. Proton nuclear magnetic resonance and spectrophotometric studies of nickel(II)-iron(II) hybrid hemoglobins

    SciTech Connect

    Shibayama, N.; Inubushi, T.; Morimoto, H.; Yonetani, T.

    1987-04-21

    Ni(II)-Fe(II) hybrid hemoglobins, ..cap alpha..(Fe)/sub 2/..beta..(Ni)/sub 2/ and ..cap alpha..(Ni)/sub 2/..beta..(Fe)/sub 2/, have been characterized by proton nuclear magnetic resonance with Ni(II) protoporphyrin IX (Ni-PP) incorporated in apoprotein, which serves as a permanent deoxyheme. ..cap alpha..(Fe)/sub 2/..beta..(Ni)/sub 2/, ..cap alpha..(Ni)/sub 2/..beta..(Fe)/sub 2/, and NiHb commonly show exchangeable proton resonances at 11 and 14 ppm, due to hydrogen-bonded protons in a deoxy-like structure. Upon binding of carbon monoxide (CO) to ..cap alpha..(Fe)/sub 2/..beta..(Ni)/sub 2/, these resonances disappear at pH 6.5 to pH 8.5. On the other hand, the complementary hybrid ..cap alpha..(Ni)/sub 2/..beta..(Fe-CO)/sub 2/ showed the 11 and 14 ppm resonances at low pH. Upon raising pH, the intensities of both resonances are reduced, although these changes are not synchronized. Electronic absorption spectra and hyperfine-shifted proton resonances indicate that the ligation of CO in the ..beta..(Fe) subunits induced changes in the coordination and spin states of Ni-PP in the ..cap alpha.. subunits. In a deoxy-like structure, the coordination of Ni-PP in the ..cap alpha.. subunits is predominantly in a low-spin (S = 0) four-coordination state, whereas in an oxy-like structure the contribution of a high-spin (S = 1) five-coordination state markedly increased. Ni-PP in the ..beta.. subunits always takes a high-spin five-coordination state regardless of solution conditions and the state of ligation in the partner ..cap alpha..(Fe) subunits. In the ..beta..(Ni) subunits, a significant downfield shift of the proximal histidyl N/sub delta/H resonance and a change in the absorption spectrum of Ni-PP were detected, upon changing the quaternary structure of the hybrid. The chemical shifts were analyzed in terms of the E11-Val methyls vs. the porphyrin rings in hybrid Hbs.

  5. Design of a compact, permanent magnet electron cyclotron resonance ion source for proton and H2(+) beam production.

    PubMed

    Jia, Xianlu; Zhang, Tianjue; Luo, Shan; Wang, Chuan; Zheng, Xia; Yin, Zhiguo; Zhong, Junqing; Wu, Longcheng; Qin, Jiuchang

    2010-02-01

    A 2.45 GHz microwave ion source was developed at China Institute of Atomic Energy (CIAE) for proton beam production of over 60 mA [B.-Q. Cui, Y.-W. Bao, L.-Q. Li, W.-S. Jiang, and R.-W. Wang, Proceedings of the High Current Electron Cyclotron Resonance (ECR) Ion Source for Proton Accelerator, APAC-2001, 2001 (unpublished)]. For various proton beam applications, another 2.45 GHz microwave ion source with a compact structure is designed and will be built at CIAE as well for high current proton beam production. It is also considered to be used for the test of H(2)(+) beam, which could be injected into the central region model cyclotron at CIAE, and accelerated to 5 MeV before extraction by stripping. The required ECR magnetic field is supplied by all the permanent magnets rather than electrical solenoids and six poles. The magnetic field distribution provided by this permanent magnets configuration is a large and uniformly volume of ECR zone, with central magnetic field of a magnitude of approximately 875 Gs [T. Taylor and J. S. C. Wills, Nucl. Instrum. Methods Phys. Res. A 309, 37 (1991)]. The field adjustment at the extraction end can be implemented by moving the position of the magnet blocks. The results of plasma, coupling with 2.45 GHz microwave in the ECR zone inside the ion source are simulated by particle-in-cell code to optimize the density by adjusting the magnetic field distribution. The design configuration of the ion source will be summarized in the paper.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Molecular Dynamics of Hexamethylbenzene at Low Temperatures: Evidence of Unconventional Magnetism Based on Rotational Motion of Protons.

    PubMed

    Yen, Fei; Zhao, Zhenzheng; Hu, Sixia; Chen, Lang

    2017-08-17

    The types of magnetism known to date are all mainly based on contributions from electron motion. We show how rotational motion of protons (H(+) ) within the methyl groups in hexamethylbenzene (C6 (CH3 )6 ) also contribute significantly to the magnetic susceptibility. Starting from below 118 K, as the rotational motion of the methyl groups set in, an associated magnetic moment positive in nature due to charge of the protons renders the susceptibility to become anomalously dependent on temperature. Starting from 20 K, the susceptibility diverges with decreasing temperature indicative of spin-spin interactions between methyl groups aligned in a previously unclassified type of anti-ferromagnetic configuration. Complementary dielectric constant measurements also show the existence of magneto-dielectric coupling. Our findings allow for the study of strongly correlated systems that are based on a species that possesses much slower dynamics. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    SciTech Connect

    Macek, Robert J.; Browman, Andrew A.; Ledford, John E.; Borden, Michael J.; O'Hara, James F.; McCrady, Rodney C.; Rybarcyk, Lawrence J.; Spickermann, Thomas; Zaugg, Thomas J.; 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.

  10. NMR spin locking of proton magnetization under a frequency-switched Lee-Goldburg pulse sequence.

    PubMed

    Fu, Riqiang; Tian, Changlin; Cross, Timothy A

    2002-01-01

    The spin dynamics of NMR spin locking of proton magnetization under a frequency-switched Lee-Goldburg (FSLG) pulse sequence is investigated for a better understanding of the line-narrowing mechanism in PISEMA experiments. For the sample of oriented 15N(1,3,5,7)-labeled gramicidin A in hydrated DMPC bilayers, it is found that the spin-lattice relaxation time T(1rho)(H) in the tilted rotating frame is about five times shorter when the 1H magnetization is spin locked at the magic angle by the FSLG sequence compared to the simple Lee-Goldburg sequence. It is believed that the rapid phase alternation of the effective fields during the FSLG cycles results in averaging of the spin lock field so that the spin lock becomes less efficient. A FSLG supercycle has been suggested here to slow the phase alternation. It has been demonstrated experimentally that a modified PISEMA pulse sequence with such supercycles gives rise to about 30% line narrowing in the dipolar dimension in the PISEMA spectra compared to a standard PISEMA pulse sequence.

  11. Brain metabolite alterations in children with primary nocturnal enuresis using proton magnetic resonance spectroscopy.

    PubMed

    Zhang, Jing; Lei, Du; Ma, Jun; Wang, Mengxing; Shen, Guohua; Wang, Hui; Yang, Guang; Du, Xiaoxia

    2014-07-01

    Nocturnal enuresis is a common developmental disorder in children; primary monosymptomatic nocturnal enuresis (PMNE) is the dominant subtype. Previous literature has suggested that the prefrontal cortex and the pons are both involved in micturition control. This study aimed to investigate the metabolic levels of the left prefrontal cortex and the pons in children with PMNE by proton magnetic resonance spectroscopy (1H-MRS). Twenty-five children with PMNE and 25 healthy children took part in our experiments. Magnetic resonance examinations were performed on a Siemens 3T Trio Tim scanner. For each subject, localized 1H-MRS was acquired from the left prefrontal cortex (mainly in brodmann area 9) and the pons with a point-resolved spectroscopy sequence with repetition time 2,000 ms, echo time 30 ms and 64 averages. The LCModel software package was used to analyze the MRS raw data, and two-sample t tests were used to determine significant differences between the two groups. The results revealed a significant reduction in metabolite to total creatine ratios of N-acetylaspartate (NAA/tCr) in the left prefrontal cortex and the pons for children with PMNE compared to healthy children. Our study suggests that metabolism is disturbed in the prefrontal cortex and the pons in children with PMNE, which may be associated with the symptoms of enuresis.

  12. Neurochemistry of drug action: insights from proton magnetic resonance spectroscopic imaging and their relevance to addiction.

    PubMed

    Licata, Stephanie C; Renshaw, Perry F

    2010-02-01

    Proton magnetic resonance spectroscopy ((1)H MRS) is a noninvasive imaging technique that permits measurement of particular compounds or metabolites within the tissue of interest. In the brain, (1)H MRS provides a snapshot of the neurochemical environment within a defined volume of interest. A search of the literature demonstrates the widespread utility of this technique for characterizing tumors, tracking the progress of neurodegenerative disease, and for understanding the neurobiological basis of psychiatric disorders. As of relatively recently, (1)H MRS has found its way into substance abuse research, and it is beginning to become recognized as a valuable complement in the brain imaging toolbox that also contains positron emission tomography, single-photon-emission computed tomography, and functional magnetic resonance imaging. Drug abuse studies using (1)H MRS have identified several biochemical changes in the brain. The most consistent alterations across drug class were reductions in N-acetylaspartate and elevations in myo-inositol, whereas changes in choline, creatine, and amino acid transmitters also were abundant. Together, the studies discussed herein provide evidence that drugs of abuse may have a profound effect on neuronal health, energy metabolism and maintenance, inflammatory processes, cell membrane turnover, and neurotransmission, and these biochemical changes may underlie the neuropathology within brain tissue that subsequently gives rise to the cognitive and behavioral impairments associated with drug addiction.

  13. Proton magnetic resonance spectroscopy in pediatric obsessive-compulsive disorder: longitudinal study before and after treatment.

    PubMed

    Lázaro, Luisa; Bargalló, Núria; Andrés, Susana; Falcón, Carles; Morer, Astrid; Junqué, Carme; Castro-Fornieles, Josefina

    2012-01-30

    Abnormalities in neurochemical compounds in obsessive-compulsive disorder (OCD) may help increase our knowledge of neurobiological abnormalities in the fronto-subcortical circuits. The aims of this exploratory study were to identify with in vivo magnetic resonance spectroscopy ((1)H-MRS) the possible alterations in neurometabolites in a group of drug naïve children and adolescents with OCD in comparison with a control group and to determine whether there was any effect of treatment on the metabolite levels. Eleven OCD children and adolescents (age range 9-17 years; 6 male, 5 female) and twelve healthy subjects with similar age, sex and estimated intellectual quotient were studied. Proton magnetic resonance spectroscopy at 1.5 T was used. We placed 3 voxels, one bilaterally located involving anterior cingulate-medial frontal regions, and one in each striatal region involving the caudate and putaminal regions. Concentrations of creatine (Cr), myo-inositol (mI), total Cho (glycerophosphocholine+phosphocholine), total NAA (N-acetyl aspartate+N-acetyl aspartylglutamate), and total Glx (glutamate+glutamine) were calculated. We found significantly lower concentrations of total Cho in left striatum in OCD patients compared with healthy subjects. The difference in Cho concentrations in left striatum between the two groups did not change over time and persisted at follow-up assessment. Like the control subjects, OCD patients undergoing pharmacological treatment and clinical recovery showed no significant changes in neurometabolic activity between the first and second evaluations.

  14. Neurochemistry of Drug Action: Insights from Proton Magnetic Resonance Spectroscopic Imaging And Their Relevance to Addiction

    PubMed Central

    Licata, Stephanie C.; Renshaw, Perry F.

    2011-01-01

    Proton magnetic resonance spectroscopy (1H MRS) is a non-invasive imaging technique that permits measurement of particular compounds or metabolites within the tissue of interest. In the brain, 1H MRS provides a snapshot of the neurochemical environment within a defined volume of interest. A search of the literature demonstrates the widespread utility of this technique for characterizing tumors, tracking the progress of neurodegenerative disease, and for understanding the neurobiological basis of psychiatric disorders. As of relatively recently, 1H MRS has found its way into substance abuse research, and it is beginning to become recognized as a valuable complement in the brain imaging toolbox that also contains positron emission tomography (PET), single photon emission computed tomography (SPECT), and functional magnetic resonance imaging (fMRI). Drug abuse studies employing 1H MRS have identified a number biochemical changes in the brain. The most consistent alterations across drug class were reductions in N-acetylaspartate and elevations in myo-inositol, while changes in choline, creatine, and amino acid transmitters also were abundant. Together, the studies discussed herein provide evidence that drugs of abuse may have a profound impact on neuronal health, energy metabolism and maintenance, inflammatory processes, cell membrane turnover, and neurotransmission, and these biochemical changes may underlie the neuropathology within brain tissue that subsequently gives rise to the cognitive and behavioral impairments associated with drug addiction. PMID:20201852

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

    NASA Astrophysics Data System (ADS)

    Acharya, B.; Alexandre, J.; Bendtz, K.; Benes, P.; Bernabéu, J.; Campbell, M.; Cecchini, S.; Chwastowski, J.; Chatterjee, A.; de Montigny, M.; Derendarz, D.; De Roeck, A.; Ellis, J. R.; Fairbairn, M.; Felea, D.; Frank, M.; Frekers, D.; Garcia, C.; Giacomelli, G.; Hasegan, D.; Kalliokoski, M.; Katre, A.; Kim, D.-W.; King, M. G. L.; Kinoshita, K.; Lacarrère, D. H.; Lee, S. C.; Leroy, C.; Lionti, A.; Margiotta, A.; Mauri, N.; Mavromatos, N. E.; Mermod, P.; Milstead, D.; Mitsou, V. A.; Orava, R.; Parker, B.; Pasqualini, L.; Patrizii, L.; Păvălas, G. E.; Pinfold, J. L.; Platkevič, M.; Popa, V.; Pozzato, M.; Pospisil, S.; Rajantie, A.; Sahnoun, Z.; Sakellariadou, M.; Sarkar, S.; Semenoff, G.; Sirri, G.; Sliwa, K.; Soluk, R.; Spurio, M.; Srivastava, Y. N.; Staszewski, R.; Suk, M.; Swain, J.; Tenti, M.; Togo, V.; Trzebinski, M.; Tuszynski, J. A.; Vento, V.; Vives, O.; Vykydal, Z.; Whyntie, T.; Widom, A.; Willems, G.; Yoon, J. H.

    2016-08-01

    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 nucleartrack detectors with surface area ~18m2, 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 8TeV proton-proton collisions at the LHC, for an integrated luminosity of 0.75 fb-1. No magnetic charge exceeding 0:5 g D (where g 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 1 g D ≤ | g| ≤ 6 g D, and model-dependent cross-section limits are obtained for Drell-Yan pair production of spin-1/2 and spin-0 monopoles for 1 g D ≤ | g| ≤ 4 g D. Under the assumption of Drell-Yan cross sections, mass limits are derived for | g| = 2 g D and | g| = 3 g D for the first time at the LHC, surpassing the results from previous collider experiments.

  16. DESIGN OF SUPERCONDUCTING COMBINED FUNCTION MAGNETS FOR THE 50 GEV PROTON BEAM LINE FOR THE J-PARC NEUTRINO EXPERIMENT.

    SciTech Connect

    WANDERER,P.; ET AL.

    2003-06-15

    Superconducting combined function magnets will be utilized for the 50GeV-750kW proton beam line for the J-PARC neutrino experiment and an R and D program has been launched at KEK. The magnet is designed to provide a combined function with a dipole field of 2.59 T and a quadrupole field of 18.7 T/m in a coil aperture of 173.4 mm. A single layer coil is proposed to reduce the fabrication cost and the coil arrangement in the 2-D cross-section results in left-right asymmetry. This paper reports the design study of the magnet.

  17. Particle selection and beam collimation system for laser-accelerated proton beam therapy.

    PubMed

    Luo, Wei; Fourkal, Eugene; Li, Jinsheng; Ma, Chang-Ming

    2005-03-01

    In a laser-accelerated proton therapy system, the initial protons have broad energy and angular distributions, which are not suitable for direct therapeutic applications. A compact particle selection and collimation device is needed to deliver small pencil beams of protons with desired energy spectra. In this work, we characterize a superconducting magnet system that produces a desired magnetic field configuration to spread the protons with different energies and emitting angles for particle selection. Four magnets are set side by side along the beam axis; each is made of NbTi wires which carry a current density of approximately 10(5) A/cm2 at 4.2 K, and produces a magnetic field of approximately 4.4 T in the corresponding region. Collimation is applied to both the entrance and the exit of the particle selection system to generate a desired proton pencil beam. In the middle of the magnet system, where the magnetic field is close to zero, a particle selection collimator allows only the protons with desired energies to pass through for therapy. Simulations of proton transport in the presence of the magnetic field show that the selected protons have successfully refocused on the beam axis after passing through the magnetic field with the optimal magnet system. The energy spread for any given characteristic proton energy has been obtained. It is shown that the energy spread is a function of the magnetic field strength and collimator size and reaches the full width at half maximum of 25 MeV for 230 MeV protons. Dose distributions have also been calculated with the GEANT3 Monte Carlo code to study the dosimetric properties of the laser-accelerated proton beams for radiation therapy applications.

  18. Detection of necrosis in human tumour xenografts by proton magnetic resonance imaging.

    PubMed Central

    Jakobsen, I.; Kaalhus, O.; Lyng, H.; Rofstad, E. K.

    1995-01-01

    Tumours with necrotic regions have an inadequate blood supply and are expected to differ from well-vascularised tumours in response to treatment. The purpose of the present work was to investigate whether proton magnetic resonance imaging (MRI) might be used to detect necrotic regions in tumours. MR images and histological sections from individual tumours of three different amelanotic human melanoma xenograft lines (BEX-t, HUX-t, SAX-t) were analysed in pairs. MRI was performed at 1.5 T using two spin-echo pulse sequences, one with a repetition time (TR) of 600 ms and echo times (TEs) of 20, 40, 60 and 80 ms and the other with a TR of 2000 ms and TEs of 20, 40, 60 and 80 ms. Spin-lattice relaxation time (T1), spin-spin relaxation time (T2) and proton density (N0) were calculated for each volume element corresponding to a pixel. Synthetic MR images, pure T1, T2 and N0 images and spin-echo images with chosen values for TR and TE were generated from these data. T1, T2 and N0 distributions of tumour subregions, corresponding to necrotic regions and regions of viable tissue as defined by histological criteria, were also generated. T1 and T2 were significantly shorter in the necrotic regions than in the regions of viable tissue in all tumours. These differences were sufficiently large to allow the generation of synthetic spin-echo images showing clear contrast between necrosis and viable tissue. Maximum contrast was achieved with TRs within the range 2800-4000 ms and TEs within the range 160-200 ms. Necrotic tissue could also be distinguished from viable tissue in pure T1 and T2 images. Consequently, the possibility exists that MRI might be used for detection of necrotic regions in tumours and hence for prediction of tumour treatment response. Images Figure 4 Figure 5 PMID:7880724

  19. 9.4T Human MRI: Preliminary Results

    PubMed Central

    Vaughan, Thomas; DelaBarre, Lance; Snyder, Carl; Tian, Jinfeng; Akgun, Can; Shrivastava, Devashish; Liu, Wanzahn; Olson, Chris; Adriany, Gregor; Strupp, John; Andersen, Peter; Gopinath, Anand; van de Moortele, Pierre-Francois; Garwood, Michael; Ugurbil, Kamil

    2014-01-01

    This work reports the preliminary results of the first human images at the new high-field benchmark of 9.4T. A 65-cm-diameter bore magnet was used together with an asymmetric 40-cm-diameter head gradient and shim set. A multichannel transmission line (transverse electromagnetic (TEM)) head coil was driven by a programmable parallel transceiver to control the relative phase and magnitude of each channel independently. These new RF field control methods facilitated compensation for RF artifacts attributed to destructive interference patterns, in order to achieve homogeneous 9.4T head images or localize anatomic targets. Prior to FDA investigational device exemptions (IDEs) and internal review board (IRB)-approved human studies, preliminary RF safety studies were performed on porcine models. These data are reported together with exit interview results from the first 44 human volunteers. Although several points for improvement are discussed, the preliminary results demonstrate the feasibility of safe and successful human imaging at 9.4T. PMID:17075852

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

    SciTech Connect

    Sjue, Sky K. L.; Morris, Christopher L.; Merrill, Frank Edward; Mariam, Fesseha Gebre; Saunders, Alexander

    2016-01-14

    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 protonimaging 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. Furthermore, comparison with a series of static calibrationimages 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.

  1. Proton nuclear magnetic resonance spectroscopic detection and determination of ethylene glycol dimethacrylate as a contaminant of methyl methacrylate raw material.

    PubMed

    Hanna, G M; Lau-Cam, C A

    1995-01-01

    A simple, specific, and accurate proton nuclear magnetic resonance (1H NMR) spectroscopic method is presented for detection and assay of ethylene glycol dimethacrylate dimer as a contaminant of methyl methacrylate monomer. In addition to minimizing exposure of the analyst to the irritant and toxic methacrylic acid esters, the proposed method requires no sample preparation. Quantitations are based on integrals for signals of methylene protons of ethylene glycol dimethacrylate at 4.37 ppm and methyl protons of methyl methacrylate at 3.70 ppm. Analysis of 10 synthetic mixtures of the monomer with 1-11% of dimer yielded a dimer recovery of 100.5 +/- 2.05% (mean +/- standard deviation). Correspondence (correlation coefficient, r = 0.9999) between the amount of dimer added and the amount found was excellent. The proposed method measures as little as 1% of dimer.

  2. Status of intense permanent magnet proton source for China-accelerator driven sub-critical system Linac

    SciTech Connect

    Wu, Q. Ma, H. Y.; Yang, Y.; Sun, L. T.; Zhang, X. Z.; Zhang, Z. M.; Zhao, H. Y.; He, Y.; Zhao, H. W.

    2016-02-15

    Two compact intense 2.45 GHz permanent magnet proton sources and their corresponding low energy beam transport (LEBT) system were developed successfully for China accelerator driven sub-critical system in 2014. Both the proton sources operate at 35 kV potential. The beams extracted from the ion source are transported by the LEBT, which is composed of two identical solenoids, to the 2.1 MeV Radio-Frequency Quadrupole (RFQ). In order to ensure the safety of the superconducting cavities during commissioning, an electrostatic-chopper has been designed and installed in the LEBT line that can chop the continuous wave beam into a pulsed one. The minimum width of the pulse is less than 10 μs and the fall/rise time of the chopper is about 20 ns. The performance of the proton source and the LEBT, such as beam current, beam profile, emittance and the impact to RFQ injection will be presented.

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

    DOE PAGES

    Sjue, Sky K. L.; Morris, Christopher L.; Merrill, Frank Edward; ...

    2016-01-14

    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 protonimaging 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.more » Furthermore, comparison with a series of static calibrationimages 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.« less

  4. A systematic review of proton magnetic resonance spectroscopy findings in sport-related concussion.

    PubMed

    Gardner, Andrew; Iverson, Grant L; Stanwell, Peter

    2014-01-01

    Traditional structural neuroimaging techniques are normal in athletes who sustain sport-related concussions and are only considered to be clinically helpful in ruling out a more serious brain injury. There is a clinical need for more sophisticated, non-invasive imaging techniques capable of detecting changes in neurophysiology after injury. Concussion is associated with neurometabolic changes including neuronal depolarization, release of excitatory neurotransmitters, ionic shifts, changes in glucose metabolism, altered cerebral blood flow, and impaired axonal function. Proton magnetic resonance spectroscopy ((1)H-MRS, or simply MRS) is capable of measuring brain biochemistry and has the potential to identify and quantify physiologic changes after concussion. The focus of the current review is to provide an overview of research findings using MRS in sport-related concussion. A systematic review of articles published in the English language, up to February 2013, was conducted. Articles were retrieved via the databases: PsychINFO, Medline, Embase, SportDiscus, Scopus, Web of Science, and Informit using key terms: magnetic resonance spectroscopy, nuclear magnetic resonance spectroscopy, neurospectroscopy, spectroscopy, two-dimensional nuclear magnetic resonance spectroscopy, correlation spectroscopy, J-spectroscopy, exchange spectroscopy, nuclear overhauser effect spectroscopy, NMR, MRS, COSY, EXSY, NOESY, 2D NMR, craniocerebral trauma, mild traumatic brain injury, mTBI, traumatic brain injury, brain concussion, concussion, brain damage, sport, athletic, and athlete. Observational, cohort, correlational, cross-sectional, and longitudinal studies were all included in the current review. The review identified 11 publications that met criteria for inclusion, comprised of data on 200 athletes and 116 controls. Nine of 11 studies reported a MRS abnormality consistent with an alteration in neurochemistry. The results support the use of MRS as a research tool for identifying

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

    PubMed

    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 < 0.01) were found for several metabolites (including an unknown metabolite) between malignant and benign ovarian cysts. Furthermore, higher concentrations in malignant- and lower in benign fluids were found compared to normal serum values, indicating local cyst wall metabolic processes in case of malignant transformation. We conclude that (1)H-nuclear magnetic resonance spectroscopy can give an 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

  6. Response of engineered cartilage tissue to biochemical agents as studied by proton magnetic resonance microscopy.

    PubMed

    Potter, K; Butler, J J; Horton, W E; Spencer, R G

    2000-07-01

    To test the hypothesis that magnetic resonance imaging (MRI) results correlate with the biochemical composition of cartilage matrix and can therefore be used to evaluate natural tissue development and the effects of biologic interventions. Chondrocytes harvested from day-16 chick embryo sterna were inoculated into an MRI-compatible hollow-fiber bioreactor. The tissue that formed over a period of 2-4 weeks was studied biochemically, histologically, and with MRI. Besides natural development, the response of the tissue to administration of retinoic acid, interleukin-1beta (IL-1beta), and daily dosing with ascorbic acid was studied. Tissue wet and dry weight, glycosaminoglycan (GAG) content, and collagen content all increased with development time, while tissue hydration decreased. The administration of retinoic acid resulted in a significant reduction in tissue wet weight, proteoglycan content, and cell number and an increase in hydration as compared with controls. Daily dosing with ascorbic acid increased tissue collagen content significantly compared with controls, while the administration of IL-1beta resulted in increased proteoglycan content. The water proton longitudinal and transverse relaxation rates correlated well with GAG and collagen concentrations of the matrix as well as with tissue hydration. In contrast, the magnetization transfer value for the tissue correlated only with total collagen. Finally, the self-diffusion coefficient of water correlated with tissue hydration. Parameters derived from MR images obtained noninvasively can be used to quantitatively assess the composition of cartilage tissue generated in a bioreactor. We conclude that MRI is a promising modality for the assessment of certain biochemical properties of cartilage in a wide variety of settings.

  7. Intra-abdominal fat burden discriminated in vivo using proton magnetic resonance spectroscopy.

    PubMed

    Walling, Brent E; Munasinghe, Jeeva; Berrigan, David; Bailey, Michael Q; Simpson, R Mark

    2007-01-01

    To assess proton magnetic resonance spectroscopy (1H-MRS) as a means to distinguish among mice with disparate intra-abdominal body fat compositions, and to measure changes in intra-abdominal fat burden during weight loss and regain. Intra-abdominal fat burden was analyzed as a ratio of integrated areas under the curves of fat to water (1)H-MRS signals collected from a region of interest standardized across B6.V-Lep(ob), C57BL/6, and A-ZIP/F mice that exhibited various genotypically related body fat compositions, ranging from obese (B6.V-Lep(ob)) to minimal body fat (A-ZIP/F). 1H-MRS analysis of fat burden was compared with intra-abdominal fat volume and with a single cross-sectional intra-abdominal fat area calculated from segmented magnetic resonance images. Similar measurements were made from obese B6.V-Lep(ob) mice before, during, and after they were induced to lose weight by leptin administration. Relative amounts of intra-abdominal fat analyzed by 1H-MRS differed significantly according to body composition and genotype of the three strains of mice (p < 0.05). Intra-abdominal fat assessed by 1H-MRS correlated with both intra-abdominal fat volume (r = 0.88, p < 0.001) and body weight (r = 0.82, p < 0.001) among, but not within, all three genotypes. During weight loss and regain, there was a significant overall pattern of changes in intra-abdominal fat quantity that occurred, which was reflected by 1H-MRS (p = 0.006). Results support the use of localized 1H-MRS for assessing differences in intra-abdominal fat. Refinements in 1H-MRS voxel region of interest size and location as well as instrument precision may result in improved correlations within certain body compositions.

  8. Changes in the distribution of low-energy trapped protons associated with the April 17, 1965, magnetic storm.

    NASA Technical Reports Server (NTRS)

    Burns, A. L.; Krimigis, S. M.

    1972-01-01

    The absolute intensity of geomagnetically trapped protons in the energy ranges from 0.52 to 4.0 MeV and from 0.90 to 1.8 MeV has been measured with the solid-state proton detector on the satellite Injun 4 for the period from Mar. 1 to May 31, 1965. A study of the temporal variations of these fluxes associated with the Apr. 17, 1965, magnetic storm shows a general redistribution of these protons for L greater than 2.5. The effect of the sudden commencement was a general depression in the intensities and a hardening of the energy spectra, although the intensities recovered to their prestorm level during the initial phase. The major redistribution was apparently initiated by the polar substorm. During the recovery phase, a secondary peak developed in the intensity profile at L of about 3.5 for 0.52-MeV protons that had no counterpart at this energy at the equator. No such peak was observed for 0.9-MeV protons.

  9. Probing astrocyte metabolism in vivo: proton magnetic resonance spectroscopy in the injured and aging brain

    PubMed Central

    Harris, Janna L.; Choi, In-Young; Brooks, William M.

    2015-01-01

    Following a brain injury, the mobilization of reactive astrocytes is part of a complex neuroinflammatory response that may have both harmful and beneficial effects. There is also evidence that astrocytes progressively accumulate in the normal aging brain, increasing in both number and size. These astrocyte changes in normal brain aging may, in the event of an injury, contribute to the exacerbated injury response and poorer outcomes observed in older traumatic brain injury (TBI) survivors. Here we present our view that proton magnetic resonance spectroscopy (1H-MRS), a neuroimaging approach that probes brain metabolism within a defined region of interest, is a promising technique that may provide insight into astrocyte metabolic changes in the injured and aging brain in vivo. Although 1H-MRS does not specifically differentiate between cell types, it quantifies certain metabolites that are highly enriched in astrocytes (e.g., Myo-inositol, mlns), or that are involved in metabolic shuttling between astrocytes and neurons (e.g., glutamate and glutamine). Here we focus on metabolites detectable by 1H-MRS that may serve as markers of astrocyte metabolic status. We review the physiological roles of these metabolites, discuss recent 1H-MRS findings in the injured and aging brain, and describe how an astrocyte metabolite profile approach might be useful in clinical medicine and clinical trials. PMID:26578948

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

    PubMed

    Zheng, Yang; Wang, Xiaoming; Zhao, Xuna

    2016-01-01

    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. Reliability of glutamate and GABA quantification using proton magnetic resonance spectroscopy.

    PubMed

    Yasen, Alia L; Smith, Jolinda; Christie, Anita D

    2017-03-16

    The consistency and reliability of proton magnetic resonance spectroscopy ((1)H-MRS) assessments of neurotransmitter concentration has not been widely examined over multiple days. The purpose of this study was to determine the reliability of glutamate and GABA measures using a single-voxel (1)H-MRS protocol in healthy men and women. Glutamate and GABA quantitations were obtained from the primary motor cortex (M1) and the dorsolateral prefrontal cortex (DLPFC) in 13 healthy individuals across 3 data collection sessions, including a baseline (Visit 1), 2-week (Visit 2), and 2-month time point (Visit 3). Glutamate concentrations were similar across visits in M1 (p=0.72) and the DLPFC (p=0.52). Reliability across days was excellent in M1 (R=0.93), and in the DLPFC (R=0.99). GABA concentrations were similar across visits in M1 (p=0.44) and in the DLPFC (p=0.59). Reliability of GABA concentration across days was excellent in M1 (R=0.93), and in the DLPFC (R=0.97). (1)H-MRS is a reliable method for quantifying glutamate and GABA concentration in M1 and the DLPFC in humans.

  12. Proton magnetic resonance spectroscopy (1H-MRS) of the cerebellum in men with schizophrenia

    PubMed Central

    Tibbo, P; Hanstock, CC; Asghar, S; Silverstone, P; Allen, PS

    2000-01-01

    OBJECTIVE: To investigate whether there are cerebellar vermis abnormalities in schizophrenia. DESIGN: Prospective imaging study with proton magnetic resonance spectroscopy (1H-MRS). SETTING: Schizophrenia clinic at a large urban hospital. PATIENTS AND CONTROLS: Twelve right-handed male patients with schizophrenia, and 12 control subjects with no psychiatric history. INTERVENTIONS: MRS data were acquired from a 2.0 x 2.0 x 2.0 cm volume of interest that included the entire cerebellar vermis. OUTCOME MEASURES: Spectral peak arising from N-acetylaspartate (NAA), phosphocreatine/creatine (Cr) and choline (Cho). RESULTS: There were no significant differences between the patients with schizophrenia and the controls in cerebellar vermis ratios of NAA to Cr (p = 0.71) or Cho to Cr (p = 0.50). CONCLUSIONS: This study does not support earlier structural studies that found abnormalities of the cerebellar vermis in schizophrenia, although it does support reported neurochemical studies. It does not rule out cerebellar involvement in schizophrenia through mechanisms such as aberrant circuitry. Larger in vivo structural/neurochemical and functional imaging studies in other parts of the cerebellum are needed. PMID:11109301

  13. Proton nuclear magnetic resonance of regenerating rat liver after partial hepatectomy

    SciTech Connect

    de Certaines, J.D.; Moulinoux, J.P.; Benoist, L.; Benard, A.; Rivet, P.

    1982-08-09

    Spin-lattice (T/sub 1/) and spin-spin (T/sub 2/) proton nuclear magnetic resonance relaxation times were measured over a 48-hours period of experimental liver regeneration in Wistar rats, T/sub 2/ showed an early significant increase reaching a plateau 30% above baseline from the 10th hrs onwards. Laparotomized control animals showed no change in T/sub 2/ values. The increase in T/sub 1/ occurred at a later stage but was no different from that in laparotomized controls. T/sub 1/ reached a peak, 20% above baseline, around the 30th hr. The changes observed were far less marked than those previously described for cancer tissue, which showed about a 60% increase in T/sub 1/ fluctuations followed a circadian pattern, with a minimum at night's end and a maximum around mid-day. No circadian rhythm was seen for T/sub 2/. The observed T/sub 1/ and T/sub 2/ changes are discussed with respect to mitotic and metabolic events known to occur during regeneration of the liver.

  14. Brain metabolism in Alzheimer disease and vascular dementia assessed by in vivo proton magnetic resonance spectroscopy.

    PubMed

    Herminghaus, Sebastian; Frölich, Lutz; Gorriz, Corrina; Pilatus, Ullrich; Dierks, Thomas; Wittsack, Hans-Jörg; Lanfermann, Heinrich; Maurer, Konrad; Zanella, Friedhelm E

    2003-07-30

    Proton magnetic resonance spectroscopy (MRS) allows the assessment of various cerebral metabolites non-invasively in vivo. Among 1H MRS-detectable metabolites, N-acetyl-aspartate and N-acetyl-aspartyl-glutamate (tNAA), trimethylamines (TMA), creatine and creatine phosphate (tCr), inositol (Ins) and glutamate (Gla) are of particular interest, since these moieties can be assigned to specific neuronal and glial metabolic pathways, membrane constituents, and energy metabolism. In this study on 94 subjects from a memory clinic population, 1H MRS results (single voxel STEAM: TE 20 ms, TR 1500 ms) on the above metabolites were assessed for five different brain regions in probable vascular dementia (VD), probable Alzheimer's disease (AD), and age-matched healthy controls. In both VD and AD, ratios of tNAA/tCr were decreased, which may be attributed to neuronal atrophy and loss, and Ins/tCr-ratios were increased indicating either enhanced gliosis or alteration of the cerebral inositol metabolism. However, the topographical distribution of the metabolic alterations in both diseases differed, revealing a temporoparietal pattern for AD and a global, subcortically pronounced pattern for VD. Furthermore, patients suffering from vascular dementia (VD) had remarkably enhanced TMA/tCr ratios, potentially due to ongoing degradation of myelin. Thus, the metabolic alterations obtained by 1H MRS in vivo allow insights into the pathophysiology of the different dementias and may be useful for diagnostic classification.

  15. Proton magnetic resonance spectroscopic imaging in pediatric low-grade gliomas.

    PubMed

    Porto, Luciana; Kieslich, Matthias; Franz, Kea; Lehrbecher, Thomas; Pilatus, Ulrich; Hattingen, Elke

    2010-10-01

    Our purpose was to investigate whether in vivo proton magnetic resonance spectroscopic imaging, using normalized concentrations of total choline (tCho) and total creatine (tCr), can differentiate between WHO grade I pilocytic astrocytoma (PA) and diffuse, fibrillary WHO grade II astrocytoma (DA) in children. Data from 16 children with astrocytomas (11 children with PA and 5 children with DA) were evaluated retrospectively. MRS was performed before treatment in all patients with histologically proven low-grade astrocytomas. Metabolite concentrations of tCho and tCr were normalized to the respective concentration in contralateral brain tissue. The Mann-Whitney U test was performed to evaluate differences between these two groups. Normalized tCho did not show any statistically significant difference between the two groups. There was a strong trend (P = 0.07) toward higher values of normalized tCr in the DA group. For 3 of 5 children with DA, lactate was detectable, but only 1 of 11 children with PA showed lactate. We concluded that choline as a single parameter is not reliable in the differential diagnosis of low-grade astrocytomas in children. Our results suggest that tCr concentrations combined with lactate will be helpful in the differential diagnosis of PA and DA in children.

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

    PubMed Central

    Zhao, Xuna

    2016-01-01

    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. PMID:27885356

  17. Measuring relative acetylcholine receptor agonist binding by selective proton nuclear magnetic resonance relaxation experiments.

    PubMed Central

    Behling, R W; Yamane, T; Navon, G; Sammon, M J; Jelinski, L W

    1988-01-01

    A method is presented that uses selective proton Nuclear Magnetic Resonance (NMR) relaxation measurements of nicotine in the presence of the acetylcholine receptor to obtain relative binding constants for acetylcholine, carbamylcholine, and muscarine. For receptors from Torpedo californica the results show that (a) the binding constants are in the order acetylcholine greater than nicotine greater than carbamylcholine greater than muscarine; (b) selective NMR measurements provide a rapid and direct method for monitoring both the specific and nonspecific binding of agonists to these receptors and to the lipid; (c) alpha-bungarotoxin can be used to distinguish between specific and nonspecific binding to the receptor; (d) the receptor--substrate interaction causes a large change in the selective relaxation time of the agonists even at concentrations 100x greater than that of the receptor. This last observation means that these measurements provide a rapid method to monitor drug binding when only small amounts of receptor are available. Furthermore, the binding strategies presented here may be useful for the NMR determination of the conformation of the ligand in its bound state. Images FIGURE 1 PMID:3395661

  18. [Effects of echo time on the liver fat quantification using proton magnetic resonance spectroscopy].

    PubMed

    Liu, Zaiyi; Liu, Xiaoying; Xu, Li; Li, Yan; Wang, Qiushi; Zheng, Junhui; Liang, Changhong

    2010-08-01

    This study was aimed to evaluate the effects of different echo time (TE) on the liver fat quantification using proton magnetic resonance spectroscopy (1H-MRS). Liver 1H-MRS was performed on 24 adult male wistar rats on a 1.5 T superconductor MR scanner. Spectrums were collected with a TR of 1500 ms and different TE of 35, 45, 55, 65, 75, 85, 95, 105, 144 ms, respectively. The water and lipid peaks, baseline of the spectrum and lipid to water ratio were evaluated. With the increment of TE, the amplitude and integrated area of the water and lipid peaks decreased, and the baseline of the spectrum and the lipid to water ratio became unstable. The lipid to water ratio determined by 1H-MRS was highly correlated with the liver fat content determined by pathological analysis at TE between 35 and 55 ms (r > 0.9) and poorly to moderately correlated at TE > or =65 ms (r < 0.9). The results indicated that long TE would compromise the liver fat quantification using 1H-MRS, and therefore short TE was strongly recommended for liver fat quantification.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. Differentiation of SCA2 from MSA-C using proton magnetic resonance spectroscopic imaging.

    PubMed

    Boesch, Sylvia M; Wolf, Christian; Seppi, Klaus; Felber, Stephan; Wenning, Gregor K; Schocke, Michael

    2007-03-01

    To assess and compare biochemical and volumetric features of the cerebellum in patients with spinocerebellar ataxia type 2 (SCA2) and patients with the cerebellar variant of multiple system atrophy (MSA-C). Nine genetically assigned SCA2 patients and six MSA-C patients who met the clinical criteria of MSA-C underwent a clinical and neuroradiological workup with respect to cerebellar features. The MR protocol consisted of a sagittal T1-weighted three-dimensional fast low-angle shot (3D FLASH) sequence and a transversal T2- and spin-density-weighted turbo spin-echo sequence. The proton magnetic resonance spectroscopic imaging ((1)H-MRSI) protocol consisted of two chemical shift imaging (CSI) sequences (echo time (TE) = 20 and 135 msec). Both short- and long-TE MR spectroscopy (MRS) images showed significant decreases in values for N-acetylaspartate to creatine (NAA/Cr), and choline to creatine (Cho/Cr) ratios in MSA-C and SCA2 compared to normal controls, though there was no difference between the two patient groups. In contrast, distinct cerebellar lactate (Lac) peaks were detected in seven SCA2 patients, and small peaks were detected in two. However, we did not detect any definite Lac peak in MSA-C or control subjects. MRSI revealed Lac pathology in SCA2 but not in MSA-C. Whether this indicates distinct pathogenetic mechanisms of cerebellar degeneration remains to be established.

  1. Brain energy metabolism in early MSA-P: A phosphorus and proton magnetic resonance spectroscopy study.

    PubMed

    Stamelou, M; Pilatus, U; Reuss, A; Respondek, G; Knake, S; Oertel, W H; Höglinger, G U

    2015-05-01

    Recently, mutations in the COQ2 gene, encoding for an enzyme involved in coenzyme Q10 biosynthesis, have been suggested to confer susceptibility risk for multiple system atrophy (MSA). Thus, the possible role of mitochondrial dysfunction in the pathophysiology of MSA has emerged. Here, we studied brain energy metabolism in vivo in early MSA-parkinsonism (MSA-P) patients and compared to healthy controls. We have used combined phosphorus and proton magnetic resonance spectroscopy to measure high- and low-energy phosphates in the basal ganglia of early (Hoehn and Yahr stage I-III), probable MSA-P patients (N = 9) compared to healthy controls (N = 9). No significant changes in the high energy phosphates and other parameters reflecting the energy status of the cells were found in the basal ganglia of MSA-P patients compared to healthy controls. N-acetylaspartate was significantly reduced in MSA-P compared to healthy controls and correlated with the Unified Multiple System Atrophy Rating Scale. Brain energy metabolism in early MSA-P is not impaired, despite the presence of impaired neuronal integrity. This may imply that mitochondrial dysfunction may not play a primary role in the pathophysiology of MSA, at least in European populations. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    SciTech Connect

    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.

  3. Anterior insula GABA levels correlate with emotional aspects of empathy: a proton magnetic resonance spectroscopy study.

    PubMed

    Wang, Qianfeng; Zhang, Zhuwei; Dong, Fang; Chen, Luguang; Zheng, Li; Guo, Xiuyan; Li, Jianqi

    2014-01-01

    Empathy is a multidimensional construct referring to the capacity to understand and share the emotional and affective states of another person. Cerebral γ-aminobutyric acid (GABA)-ergic levels are associated with a variety of neurological and psychiatric disorders. However, the role of the GABA system in different dimensions of empathy has not been investigated. Thirty-two right-handed healthy volunteers took part in this study. We used proton magnetic resonance spectroscopy to determine GABA concentrations in the anterior insula (AI) and the anterior cingulate cortex (ACC) and to examine the relationship between the GABA concentrations and the subcomponents of empathy evaluated by the Interpersonal Reactivity Index (IRI). Pearson correlation analyses (two-tailed) showed that AI GABA was significantly associated with the empathy concern score (r = 0.584, p<0.05) and the personal distress score (r = 0.538, p<0.05) but not significantly associated with other empathy subscales. No significant correlation was found between ACC GABA and empathy subscores. Left AI GABA was positively correlated with the emotional aspects of empathy. These preliminary findings call into question whether AI GABA alterations might predict empathy dysfunction in major psychiatric disorders such as autism and schizophrenia, which have been described as deficits in emotional empathic abilities.

  4. Correction of proton resonance frequency shift temperature maps for magnetic field disturbances caused by breathing

    NASA Astrophysics Data System (ADS)

    Shmatukha, Andriy V.; Bakker, Chris J. G.

    2006-09-01

    Respiratory induced resonance offset (RIRO) is a periodic disturbance of a magnetic field due to breathing. Such disturbance handicaps the accuracy of the proton resonance frequency shift (PRFS) method of MRI temperature mapping in anatomies situated nearby the lungs and chest wall. In this work, we propose a method capable of minimizing errors caused by RIRO in PRFS temperature maps. In this method, a set of baseline images characterizing RIRO at a variety of respiratory cycle instants is acquired before the thermal treatment starts. During the treatment, the temperature evolution is found from two successive images. Then, the calculated temperature changes are corrected for the additional contribution caused by RIRO using the pre-treatment baseline images acquired at the identical instances of the respiratory cycle. Our method is shown to improve the accuracy and stability of PRFS temperature maps in the presence of RIRO and inter-scan motion in phantom and volunteers' breathing experiments. Our method is also shown to be applicable to anatomies moving during breathing if a proper registration procedure is applied.

  5. Absolute quantification of carnosine in human calf muscle by proton magnetic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Özdemir, Mahir S.; Reyngoudt, Harmen; DeDeene, Yves; Sazak, Hakan S.; Fieremans, Els; Delputte, Steven; D'Asseler, Yves; Derave, Wim; Lemahieu, Ignace; Achten, Eric

    2007-12-01

    Carnosine has been shown to be present in the skeletal muscle and in the brain of a variety of animals and humans. Despite the various physiological functions assigned to this metabolite, its exact role remains unclear. It has been suggested that carnosine plays a role in buffering in the intracellular physiological pHi range in skeletal muscle as a result of accepting hydrogen ions released in the development of fatigue during intensive exercise. It is thus postulated that the concentration of carnosine is an indicator for the extent of the buffering capacity. However, the determination of the concentration of this metabolite has only been performed by means of muscle biopsy, which is an invasive procedure. In this paper, we utilized proton magnetic resonance spectroscopy (1H MRS) in order to perform absolute quantification of carnosine in vivo non-invasively. The method was verified by phantom experiments and in vivo measurements in the calf muscles of athletes and untrained volunteers. The measured mean concentrations in the soleus and the gastrocnemius muscles were found to be 2.81 ± 0.57/4.8 ± 1.59 mM (mean ± SD) for athletes and 2.58 ± 0.65/3.3 ± 0.32 mM for untrained volunteers, respectively. These values are in agreement with previously reported biopsy-based results. Our results suggest that 1H MRS can provide an alternative method for non-invasively determining carnosine concentration in human calf muscle in vivo.

  6. Investigation of the neuroprotective effects of bee-venom acupuncture in a mouse model of Parkinson's disease by using immunohistochemistry and In-vivo 1H magnetic resonance spectroscopy at 9.4 T

    NASA Astrophysics Data System (ADS)

    Yoon, Moon-Hyun; Lee, Do-Wan; Kim, Hyun-Jin; Chung, Jin-Yeung; Doo, Ah-Reum; Park, Hi-Joon; Kim, Seung-Nam; Choe, Bo-Young

    2013-01-01

    Neuroprotective therapeutics slows down the degeneration process in animal models of Parkinson's disease (PD). The neuronal survival in PD animal models is often measured by using immunohistochemistry. However, dynamic changes in the pathology of the brain cannot be explored with this technique. Application of in-vivo 1H magnetic resonance spectroscopy (1H MRS) can cover this shortcoming, as these techniques are non-invasive and can be repeated over time in the same animal. Thus, the sensitivity of both techniques to measure changes in the PD pathology was explored in an experiment studying the neuroprotective effects of the vigilance enhancer bee-venom (BV) in a mouse model of PD. The mice were pre-treated with 0.02-ml BV administered to the acupuncture point GB34 (Yangneungcheon) once every 3 days for 2 weeks. Three groups were classified as control, MPTP-intoxicated PD model and BV-treated mice. Outer volume suppression combined with the ultra-short echo-time STEAM (TE = 2.2 ms, TM = 20 ms, TR = 5000 ms) was used for localized in-vivo 1H MRS. Based on the 1H MRS spectral analysis, substantial changes of the neurochemical profiles were evaluated in the three investigated groups. In particular, the glutamate complex (Glx)/creatine (Cr) ratio (7.72 ± 1.25) in the PD group was significantly increased compared to that in the control group (3.93 ± 2.21, P = 0.001). Compared to the baseline values, the Glx/Cr ratio of the BV-treated group was significantly decreased 2 weeks after MPTP intoxication (one-way ANOVA, p < 0.05). In conclusion, the present study demonstrated that neurochemical alterations occurred in the three groups and that the neuroprotective effects of the BV acupuncture in a mouse model of PD could be quantified by using immunohistochemistry and 1H MRS.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    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.

  11. Proton magnetic resonance spectroscopy in the evaluation of children with congenital heart disease and acute central nervous system injury.

    PubMed

    Ashwal, S; Holshouser, B A; Hinshaw, D B; Schell, R M; Bailey, L

    1996-08-01

    We studied nine infants and children, aged 1 week to 42 months, with severe acute central nervous system injuries associated with cardiac disease or corrective operations by means of single-voxel proton magnetic resonance spectroscopy to determine whether this technique would be useful in predicting neurologic outcome. Proton magnetic resonance spectroscopic data were acquired from the occipital gray and parietal white matter (8 cm3 volume, stimulated echo-acquisition mode sequence with echo time of 20 msec and repetition time of 3.0 seconds) a median of 9 days after operation (range 3 to 42 days). Data were expressed as ratios of areas under metabolite peaks, including N-acetyl compounds, choline-containing compounds, creatine and phosphocreatine, and lactate. Four patients had cerebral insults before operation, one had both a preoperative and a perioperative insult, three had perioperative insults, and one had a prolonged cardiac arrest 2 days after operation. Outcomes (Glasgow Outcome Scale scores) were assigned at discharge and 6 to 12 months after injury. Six patients were in a vegetative state or had severe impairment at discharge, and two still had severe impairment at 6- to 12-month follow-up. Proton magnetic resonance spectroscopy showed lactate in these two patients, along with markedly reduced ratios of N-acetyl compounds to creatine compounds. The other four patients with severe impairment recovered to a level of mild disability at follow-up. Proton magnetic resonance spectroscopy showed no lactate in these four patients; however, one patient showed moderately reduced ratio of N-acetyl compounds to creatine compounds. The three patients who had mild or moderate impairment at discharge showed no lactate and mild or no changes in metabolite ratios; follow-up revealed normal or mild outcomes. Overall, we found that the presence of lactate and markedly reduced ratios of N-acetyl compounds to creatine compounds were predictive of severe outcomes at discharge

  12. About possibility of primary cosmic rays proton acceleration up to super-high relativistic energies in the Neutral Layer of the Interplanetary Magnetic Field (IMF)

    NASA Astrophysics Data System (ADS)

    Khazaradze, Nodar; Vanishvili, George; Bakradze, Themur; Kordzadze, Lia; Elizbarashvili, Misha; Bazerashvili, Eka

    2013-02-01

    Theoretical considerations concerning of the charged particles acceleration in general, and in particular, the peculiarities of protons acceleration in the Neutral Layer of Cosmic Space, in the frame of Maxwell Electro-Magnetic Field Theory have been reviewed on the article. A brief historical review of events is given, indicating that protons can be speeding up to ultra-relativistic energies in the Neutral Layer of the Interplanetary Magnetic Field, which is affirmed by anomalously high number of cosmic μ-mesons, generated by protons, through the decay of π- and -mesons, have been discovered in lower layers of the Earth's Atmosphere, as well as in a great depths of underground

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

    USDA-ARS?s Scientific Manuscript database

    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...

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

    PubMed

    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.

  15. APOE genotype modulates proton magnetic resonance spectroscopy metabolites in the aging brain.

    PubMed

    Gomar, Jesus J; Gordon, Marc L; Dickinson, Dwight; Kingsley, Peter B; Uluğ, Aziz M; Keehlisen, Lynda; Huet, Sarah; Buthorn, Justin J; Koppel, Jeremy; Christen, Erica; Conejero-Goldberg, Concepcion; Davies, Peter; Goldberg, Terry E

    2014-05-01

    Proton magnetic resonance spectroscopy ((1)H-MRS) studies on healthy aging have reported inconsistent findings and have not systematically taken into account the possible modulatory effect of APOE genotype. We aimed to quantify brain metabolite changes in healthy subjects in relation to age and the presence of the APOE E4 genetic risk factor for Alzheimer's disease. Additionally, we examined these measures in relation to cognition. We studied a cohort of 112 normal adults between 50 and 86 years old who were genotyped for APOE genetic polymorphism. Measurements of (1)H-MRS metabolites were obtained in the posterior cingulate and precuneus region. Measures of general cognitive functioning, memory, executive function, semantic fluency, and speed of processing were also obtained. General linear model analysis demonstrated that older APOE E4 carriers had significantly higher choline/creatine and myo-inositol/creatine ratios than APOE E3 homozygotes. Structural equation modeling resulted in a model with an excellent goodness of fit and in which the APOE × age interaction and APOE status each had a significant effect on (1)H-MRS metabolites (choline/creatine and myo-inositol/creatine). Furthermore, the APOE × age variable modulation of cognition was mediated by (1)H-MRS metabolites. In a healthy aging normal population, choline/creatine and myo-inositol/creatine ratios were significantly increased in APOE E4 carriers, suggesting the presence of neuroinflammatory processes and greater membrane turnover in older carriers. Structural equation modeling analysis confirmed these possible neurodegenerative markers and also indicated the mediator role of these metabolites on cognitive performance among older APOE E4 carriers. Copyright © 2014 Society of Biological Psychiatry. All rights reserved.

  16. A longitudinal proton magnetic resonance spectroscopy study of mild traumatic brain injury.

    PubMed

    Yeo, Ronald A; Gasparovic, Charles; Merideth, Flannery; Ruhl, David; Doezema, David; Mayer, Andrew R

    2011-01-01

    Despite the prevalence and impact of mild traumatic brain injury (mTBI), common clinical assessment methods for mTBI have insufficient sensitivity and specificity. Moreover, few researchers have attempted to document underlying changes in physiology as a function of recovery from mTBI. Proton magnetic resonance spectroscopy (¹H-MRS) was used to assess neurometabolite concentrations in a supraventricular tissue slab in 30 individuals with semi-acute mTBI, and 30 sex-, age-, and education-matched controls. No significant group differences were evident on traditional measures of attention, memory, working memory, processing speed, and executive skills, though the mTBI group reported significantly more somatic, cognitive, and emotional symptoms. At a mean of 13 days post-injury, white matter concentrations of creatine (Cre) and phosphocreatine (PCre) and the combined glutamate-glutamine signal (Glx) were elevated in the mTBI group, while gray matter concentrations of Glx were reduced. Partial normalization of these three neurometabolites and N-acetyl aspartate occurred in the early days post-injury, during the semi-acute period of recovery. In addition, 17 mTBI patients (57%) returned for a follow-up evaluation (mean = 120 days post-injury). A significant group × time interaction indicated recovery in the mTBI group for gray matter Glx, and trends toward recovery in white matter Cre and Glx. An estimate of premorbid intelligence predicted the magnitude of neurometabolite normalization over the follow-up interval for the mTBI group, indicating that biological factors underlying intelligence may also be associated with more rapid recovery.

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

    PubMed

    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 < 0.001 and modified Japanese Orthopaedic Association: P < 0.001). There was a significant decrease in the N-acetylaspartate/creatine metabolite ratio in the motor cortex of the myelopathy group (1.21 ± 0.07) compared with the right (1.37 ± 0.03; P = 0.01) and

  18. Predicting the outcome of grade II glioma treated with temozolomide using proton magnetic resonance spectroscopy

    PubMed Central

    Guillevin, R; Menuel, C; Taillibert, S; Capelle, L; Costalat, R; Abud, L; Habas, C; De Marco, G; Hoang-Xuan, K; Chiras, J; Vallée, J-N

    2011-01-01

    Background: This study was designed to evaluate proton magnetic resonance spectroscopy (1H-MRS) for monitoring the WHO grade II glioma (low-grade glioma (LGG)) treated with temozolomide (TMZ). Methods: This prospective study included adult patients with progressive LGG that was confirmed by magnetic resonance imaging (MRI). Temozolomide was administered at every 28 days. Response to TMZ was evaluated by monthly MRI examinations that included MRI with volumetric calculations and 1H-MRS for assessing Cho/Cr and Cho/NAA ratios. Univariate, multivariate and receiver-operating characteristic statistical analyses were performed on the results. Results: A total of 21 LGGs from 31 patients were included in the study, and followed for at least n=14 months during treatment. A total of 18 (86%) patients experienced a decrease in tumour volume with a greater decrease of metabolic ratios. Subsequently, five (28%) of these tumours resumed growth despite the continuation of TMZ administration with an earlier increase of metabolic ratios of 2 months. Three (14%) patients did not show any volume or metabolic change. The evolutions of the metabolic ratios, mean(Cho/Cr)n and mean(Cho/NAA)n, were significantly correlated over time (Spearman ρ=+0.95) and followed a logarithmic regression (P>0.001). The evolutions over time of metabolic ratios, mean(Cho/Cr)n and mean(Cho/NAA)n, were significantly correlated with the evolution of the mean relative decrease of tumour volume, mean(ΔVn/Vo), according to a linear regression (P<0.001) in the ‘response/no relapse' patient group, and with the evolution of the mean tumour volume (meanVn), according to an exponential regression (P<0.001) in the ‘response/relapse' patient group. The mean relative decrease of metabolic ratio, mean(Δ(Cho/Cr)n/(Cho/Cr)o), at n=3 months was predictive of tumour response over the 14 months of follow-up. The mean relative change between metabolic ratios, mean((Cho/NAA)n−(Cho/Cr)n)/(Cho/NAA)n, at n=4 months was

  19. NMR properties of human median nerve at 3 T: proton density, T1, T2, and magnetization transfer.

    PubMed

    Gambarota, Giulio; Mekle, Ralf; Mlynárik, Vladimír; Krueger, Gunnar

    2009-04-01

    To measure the proton density (PD), the T1 and T2 relaxation time, and magnetization transfer (MT) effects in human median nerve at 3 T and to compare them with the corresponding values in muscle. Measurements of the T1 and T2 relaxation time were performed with an inversion recovery and a Carr-Purcell-Meiboom-Gill (CPMG) imaging sequence, respectively. The MT ratio was measured by acquiring two sets of 3D spoiled gradient-echo images, with and without a Gaussian saturation pulse. The median nerve T1 was 1410 +/- 70 msec. The T2 decay consisted of two components, with average T2 values of 26 +/- 2 msec and 96 +/- 3 msec and normalized amplitudes of 78 +/- 4% and 22 +/- 4%, respectively. The dominant component is likely to reflect myelin water and connective tissue, and the less abundant component originates possibly from intra-axonal water protons. The value of proton density of MRI-visible protons in median nerve was 81 +/- 3% that of muscle. The MT ratio in median nerve (40.3 +/- 2.0%) was smaller than in muscle (45.4 +/- 0.5%). MRI-relevant properties, such as PD, T1 and T2 relaxation time, and MT ratio were measured in human median nerve at 3 T and were in many respects similar to those of muscle.

  20. MO-G-18C-07: Improving T2 Determination and Quantification of Lipid Methylene Protons in Proton Magnetic Resonance Spectroscopy at 3 T

    SciTech Connect

    Breitkreutz, D.; Fallone, B. G.; Yahya, A.

    2014-06-15

    Purpose: To improve proton magnetic resonance spectroscopy (MRS) transverse relaxation (T{sub 2}) determination and quantification of lipid methylene chain (1.3 ppm) protons by rewinding their J-coupling evolution. Methods: MRS experiments were performed on four lipid phantoms, namely, almond, corn, sunflower and oleic acid, using a 3 T Philips MRI scanner with a transmit/receive birdcage head coil. Two PRESS (Point RESolved Spectroscopy) pulse sequences were used. The first PRESS sequence employed standard bandwidth (BW) (∼550 Hz) RF (radiofrequency) refocussing pulses, while the second used refocussing pulses of narrow BW (∼50 Hz) designed to rewind J-coupling evolution of the methylene protons in the voxel of interest. Signal was acquired with each sequence from a 5×5×5 mm{sup 3} voxel, with a repetition time (TR) of 3000 ms, and with echo times (TE) of 100 to 200 ms in steps of 20 ms. 2048 sample points were measured with a 2000 Hz sampling bandwidth. Additionally, 30 mm outer volume suppression slabs were used to suppress signal outside the voxel of interest. The frequency of the RF pulses was set to that of the methylene resonance. Methylene peak areas were calculated and fitted in MATLAB to a monexponentially decaying function of the form M{sub 0}exp(-TE/T{sub 2}), where M{sub 0} is the extrapolated area when TE = 0 ms and yields a measure of concentration. Results: The determined values of M{sub 0} and T{sub 2} increased for all fatty acids when using the PRESS sequence with narrow BW refocussing pulses. M{sub 0} and T{sub 2} values increased by an average amount (over all the phantoms) of 31% and 14%, respectively. Conclusion: This investigation has demonstrated that J-coupling interactions of lipid methylene protons causes non-negligible signal losses which, if not accounted for, Result in underestimations of their levels and T{sub 2} values when performing MRS measurements. Funded by the Natural Sciences and Engineering Research Council of Canada

  1. The Influence Gradient Drift in the Interplanetary Magnetic field (IMF) on the Spectra of Solar Energetic Protons (SEP) at Earth as a Function of Heliographic Latitude

    NASA Astrophysics Data System (ADS)

    Franklin, D. M.; Falconer, D. A.; Adams, J. H., Jr.

    2014-12-01

    Solar Energetic Particles (SEP) consists of Protons, Electrons and Ions accelerated in Solar flares and/or Coronal Mass Ejections (CME's). Current models for the interplanetary transport of SEPs neglect the effect of magnetic gradient drift because other effects are thought to dominate. This may not be the case for high energy SEPs. We report an experimental test for evidence of magnetic gradient drift using high energy proton data from large SEPs from Goddard Medium Energy (GME) on IMP-8 and the Energetic Particle System (EPS) on GOES. We identified the SEPs with measured proton fluxes above 50 MeV and measured their spectra. We also identified the hemispheric coordinates of the sites where these events originated. We compared the event-integrated proton differential energy spectra from the northern and southern hemispheres of the sun to search for difference that could be ascribed to the effects of magnetic gradient drift. The results of this comparison will be presented.

  2. Graphene oxide-Fe3O4 nanoparticle composite with high transverse proton relaxivity value for magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Venkatesha, N.; Poojar, Pavan; Qurishi, Yasrib; Geethanath, Sairam; Srivastava, Chandan

    2015-04-01

    The potential of graphene oxide-Fe3O4 nanoparticle (GO-Fe3O4) 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-Fe3O4 composites synthesized by precipitating Fe3O4 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-Fe3O4 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-Fe3O4 composites possessed good biocompatibility with normal cell lines, whereas they exhibited considerable toxicity towards breast cancer cells.

  3. Apoptotic depletion of CD4+ T cells in idiopathic CD4+ T lymphocytopenia.

    PubMed Central

    Laurence, J; Mitra, D; Steiner, M; Lynch, D H; Siegal, F P; Staiano-Coico, L

    1996-01-01

    Progressive loss of CD4+ T lymphocytes, accompanied by opportunistic infections characteristic of the acquired immune deficiency syndrome, ahs been reported in the absence of any known etiology. The pathogenesis of this syndrome, a subset of idiopathic CD4+ T lymphocytopenia (ICL), is uncertain. We report that CD4+ T cells from seven of eight ICL patients underwent accelerated programmed cell death, a process facilitated by T cell receptor cross-linking. Apoptosis was associated with enhanced expression of Fas and Fas ligand in unstimulated cell populations, and partially inhibited by soluble anti-Fas mAb. In addition, apoptosis was suppressed by aurintricarboxylic acid, an inhibitor of calcium-dependent endonucleases and proteases, in cells from four of seven patients, The in vivo significance of these findings was supported by three factors: the absence of accelerated apoptosis in persons with stable, physiologic CD4 lymphopenia without clinical immune deficiency; detection of serum antihistone H2B autoantibodies, one consequence of DNA fragmentation, in some patients; and its selectivity, with apoptosis limited to the CD4 population in some, and occurring among CD8+ T cells predominantly in those individuals with marked depletion of both CD4+ T lymphocytes linked to clinical immune suppression have evidence for accelerated T cell apoptosis in vitro that may be pathophysiologic and amenable to therapy with apoptosis inhibitors. PMID:8609222

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  6. Acoustic noise reduction in a 4 T MRI scanner.

    PubMed

    Mechefske, Chris K; Geris, Ryan; Gati, Joseph S; Rutt, Brian K

    2002-01-01

    High-field, high-speed magnetic resonance imaging (MRI) can generate high levels of noise. There is ongoing concern in the medical and imaging research communities regarding the detrimental effects of high acoustic levels on auditory function, patient anxiety, verbal communication between patients and health care workers and ultimately MR image quality. In order to effectively suppress the noise levels inside MRI scanners, the sound field needs to be accurately measured and characterized. This paper presents the results of measurements of the sound radiation from a gradient coil cylinder within a 4 T MRI scanner under a variety of conditions. These measurement results show: (1) that noise levels can be significantly reduced through the use of an appropriately designed passive acoustic liner; and (2) the true noise levels that are experienced by patients during echo planar imaging.

  7. Role of LAP(+)CD4(+) T cells in the tumor microenvironment of colorectal cancer.

    PubMed

    Zhong, Wu; Jiang, Zhi-Yuan; Zhang, Lei; Huang, Jia-Hao; Wang, Shi-Jun; Liao, Cun; Cai, Bin; Chen, Li-Sheng; Zhang, Sen; Guo, Yun; Cao, Yun-Fei; Gao, Feng

    2017-01-21

    To investigate the abundance and potential functions of LAP(+)CD4(+) T cells in colorectal cancer (CRC). Proportions of LAP(+)CD4(+) T cells were examined in peripheral blood and tumor/paratumor tissues of CRC patients and healthy controls using flow cytometry. Expression of phenotypic markers such as forkhead box (Fox)p3, cytotoxic T-lymphocyte-associated protein (CTLA)-4, chemokine CC receptor (CCR)4 and CCR5 was measured using flow cytometry. LAP(-)CD4(+) and LAP(+)CD4(+) T cells were isolated using a magnetic cell-sorting system and cell purity was analyzed by flow cytometry. Real-time quantitative polymerase chain reaction was used to measure expression of cytokines interleukin (IL)-10 and transforming growth factor (TGF)-β. The proportion of LAP(+)CD4(+) T cells was significantly higher in peripheral blood from patients (9.44% ± 3.18%) than healthy controls (1.49% ± 1.00%, P < 0.001). Among patients, the proportion of LAP(+)CD4(+) T cells was significantly higher in tumor tissues (11.76% ± 3.74%) compared with paratumor tissues (3.87% ± 1.64%, P < 0.001). We also observed positive correlations between the proportion of LAP(+)CD4(+) T cells and TNM stage (P < 0.001), distant metastasis (P < 0.001) and serum level of carcinoembryonic antigen (P < 0.05). Magnetic-activated cell sorting gave an overall enrichment of LAP(+)CD4(+) T cells (95.02% ± 2.87%), which was similar for LAP(-)CD4(+) T cells (94.75% ± 2.76%). In contrast to LAP(-)CD4(+) T cells, LAP(+)CD4(+) T cells showed lower Foxp3 expression but significantly higher levels of CTLA-4, CCR4 and CCR5 (P < 0.01). LAP(+)CD4(+) T cells expressed significantly larger amounts of IL-10 and TGF-β but lower levels of IL-2, IL-4, IL-17 and interferon-γ, compared with LAP(-)CD4(+) T cells. LAP(+)CD4(+) T cells accumulated in the tumor microenvironment of CRC patients and were involved in immune evasion mediated by IL-10 and TGF-β.

  8. Role of LAP+CD4+ T cells in the tumor microenvironment of colorectal cancer

    PubMed Central

    Zhong, Wu; Jiang, Zhi-Yuan; Zhang, Lei; Huang, Jia-Hao; Wang, Shi-Jun; Liao, Cun; Cai, Bin; Chen, Li-Sheng; Zhang, Sen; Guo, Yun; Cao, Yun-Fei; Gao, Feng

    2017-01-01

    AIM To investigate the abundance and potential functions of LAP+CD4+ T cells in colorectal cancer (CRC). METHODS Proportions of LAP+CD4+ T cells were examined in peripheral blood and tumor/paratumor tissues of CRC patients and healthy controls using flow cytometry. Expression of phenotypic markers such as forkhead box (Fox)p3, cytotoxic T-lymphocyte-associated protein (CTLA)-4, chemokine CC receptor (CCR)4 and CCR5 was measured using flow cytometry. LAP-CD4+ and LAP+CD4+ T cells were isolated using a magnetic cell-sorting system and cell purity was analyzed by flow cytometry. Real-time quantitative polymerase chain reaction was used to measure expression of cytokines interleukin (IL)-10 and transforming growth factor (TGF)-β. RESULTS The proportion of LAP+CD4+ T cells was significantly higher in peripheral blood from patients (9.44% ± 3.18%) than healthy controls (1.49% ± 1.00%, P < 0.001). Among patients, the proportion of LAP+CD4+ T cells was significantly higher in tumor tissues (11.76% ± 3.74%) compared with paratumor tissues (3.87% ± 1.64%, P < 0.001). We also observed positive correlations between the proportion of LAP+CD4+ T cells and TNM stage (P < 0.001), distant metastasis (P < 0.001) and serum level of carcinoembryonic antigen (P < 0.05). Magnetic-activated cell sorting gave an overall enrichment of LAP+CD4+ T cells (95.02% ± 2.87%), which was similar for LAP-CD4+ T cells (94.75% ± 2.76%). In contrast to LAP-CD4+ T cells, LAP+CD4+ T cells showed lower Foxp3 expression but significantly higher levels of CTLA-4, CCR4 and CCR5 (P < 0.01). LAP+CD4+ T cells expressed significantly larger amounts of IL-10 and TGF-β but lower levels of IL-2, IL-4, IL-17 and interferon-γ, compared with LAP-CD4+ T cells. CONCLUSION LAP+CD4+ T cells accumulated in the tumor microenvironment of CRC patients and were involved in immune evasion mediated by IL-10 and TGF-β. PMID:28210081

  9. High resolution proton magnetic resonance spectroscopy of human brain and liver

    SciTech Connect

    Barany, M.; Spigos, D.G.; Mok, E.; Venkatasubramanian, P.N.; Wilbur, A.C.; Langer, B.G.

    1987-01-01

    Water-suppressed and slice-selective proton spectra of live human brain exhibited several resonances that were tentatively assigned to metabolites such as N-acetylaspartate, glutamate, phosphocreatine and creatine, choline derivatives, and taurine. In the liver spectrum of a healthy volunteer, the major resonance was tentatively assigned to a fatty acyl methylene and the minor resonances to protons in carnitine, taurine, glutamate, and glutamine. In the spectrum of a cancerous liver, resonances in addition to those present in the normal liver were seen. Protein degradation in the liver with cancer was indicated by resonances from urea and from the ring protons in tryptophan, tyrosine, and phenylalanine. Furthermore, increased nucleic acid synthesis was indicated by resonances from nucleotide protons.

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

    DOE PAGES

    Maruyama, Tomoyuki; Cheoun, Myung-Ki; Kajino, Toshitaka; ...

    2016-03-26

    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 n(i, f) similar to 10(4)-10(5). 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 canmore » infer the decay width in more realistic magnetic fields of 10(15) G, where n(i, f) similar to 10(12)-10(13), from the results for n(i, f) similar to 10(4)-10(5). The resultant pion intensity and angular distributions for realistic magnetic field strengths are presented and their physical implications discussed. (C) 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP(3).« less

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

    SciTech Connect

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

    2016-03-26

    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 n(i, f) similar to 10(4)-10(5). 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 10(15) G, where n(i, f) similar to 10(12)-10(13), from the results for n(i, f) similar to 10(4)-10(5). The resultant pion intensity and angular distributions for realistic magnetic field strengths are presented and their physical implications discussed. (C) 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP(3).

  12. Magnetic field dependence of proton relaxation rates in tissue with added Mn2+: rabbit liver and kidney.

    PubMed

    Koenig, S H; Brown, R D; Goldstein, E J; Burnett, K R; Wolf, G L

    1985-04-01

    Since contrast in magnetic resonance imaging (MRI) is so sensitive to the magnetic relaxation rates of tissue protons, the use of paramagnetic ions to alter contrast in a tissue-specific fashion is an alluring prospect. The influence of these ions on the proton relaxation rates in homogeneous solutions is known to vary dramatically according to whether the ions are present as hydrated aquoions, in solute chelate, or immobilized in macromolecules. In tissue, there is the additional complication of access of water to the ions. In the present study, Mn2+ ions were introduced into rabbits both orally and intravenously in various chemical complexes. Accumulation of these ions in rabbit liver is demonstrated here, qualitatively, by MRI. The quantitation of the change in relaxation rates is investigated in excised samples of liver and kidney by study of the magnetic field dependence (dispersion) of the relaxation rates of the protons (NMRD profiles) of tissue water. Results are presented for several sets of experiments, including dose-response data for weakly chelated Mn2+ and time-response data for free and complexed Mn2+. The general findings are that, for liver, the response (the increment in the NMRD profile) is relatively rapid (less than 2 m); that it is relatively independent of how, or in what form, the Mn2+ is introduced; that it persists for several hours (at least); and that it saturates with increasing body load of Mn2+. Moreover, from the form of the NMRD profiles of liver, it is clear that the Mn2+ ions are bound irrotationally, perhaps to cell membrane, and, when introduced in chelated form, can become separated even from strongly associated chelate complexes. For kidney, the results are qualitatively similar, though different in detail.

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

    NASA Astrophysics Data System (ADS)

    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

  14. Listing of 502 Times When the Ulysses Magnetic Fields Instrument Observed Waves Due to Newborn Interstellar Pickup Protons

    NASA Astrophysics Data System (ADS)

    Cannon, Bradford E.; Smith, Charles W.; Isenberg, Philip A.; Vasquez, Bernard J.; Joyce, Colin J.; Murphy, Neil; Nuno, Raquel G.

    2017-05-01

    In two earlier publications we analyzed 502 intervals of magnetic waves excited by newborn interstellar pickup protons that were observed by the Ulysses spacecraft. Due to the considerable effort required in identifying these events, we provide a list of the times for the 502 wave event intervals previously identified. In the process, we provide a brief description of how the waves were found and what their properties are. We also remind the reader of the conditions that permit the waves to reach observable levels and explain why the waves are not seen more often.

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

    PubMed

    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. 32 CFR 1630.46 - Class 4-T: Treaty alien.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 6 2014-07-01 2014-07-01 false Class 4-T: Treaty alien. 1630.46 Section 1630.46 National Defense Other Regulations Relating to National Defense SELECTIVE SERVICE SYSTEM CLASSIFICATION RULES § 1630.46 Class 4-T: Treaty alien. In Class 4-T shall be placed any registrant who is an alien who...

  17. 32 CFR 1630.46 - Class 4-T: Treaty alien.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 6 2013-07-01 2013-07-01 false Class 4-T: Treaty alien. 1630.46 Section 1630.46 National Defense Other Regulations Relating to National Defense SELECTIVE SERVICE SYSTEM CLASSIFICATION RULES § 1630.46 Class 4-T: Treaty alien. In Class 4-T shall be placed any registrant who is an alien who...

  18. 32 CFR 1630.46 - Class 4-T: Treaty alien.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 6 2012-07-01 2012-07-01 false Class 4-T: Treaty alien. 1630.46 Section 1630.46 National Defense Other Regulations Relating to National Defense SELECTIVE SERVICE SYSTEM CLASSIFICATION RULES § 1630.46 Class 4-T: Treaty alien. In Class 4-T shall be placed any registrant who is an alien who...

  19. 32 CFR 1630.46 - Class 4-T: Treaty alien.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 6 2011-07-01 2011-07-01 false Class 4-T: Treaty alien. 1630.46 Section 1630.46 National Defense Other Regulations Relating to National Defense SELECTIVE SERVICE SYSTEM CLASSIFICATION RULES § 1630.46 Class 4-T: Treaty alien. In Class 4-T shall be placed any registrant who is an alien...

  20. 32 CFR 1630.46 - Class 4-T: Treaty alien.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Class 4-T: Treaty alien. 1630.46 Section 1630.46 National Defense Other Regulations Relating to National Defense SELECTIVE SERVICE SYSTEM CLASSIFICATION RULES § 1630.46 Class 4-T: Treaty alien. In Class 4-T shall be placed any registrant who is an alien...

  1. Proton nuclear magnetic resonance studies on bulge-containing DNA oligonucleotides from a mutational hot-spot sequence

    SciTech Connect

    Woodson, S.A.; Crothers, D.M.

    1987-02-10

    A series of bulge-containing and normal double-helical synthetic oligodeoxyribonucleotides, of sequence corresponding to a frame-shift mutational hot spot in the lambda C/sub I/ gene, are compared by proton magnetic resonance spectroscopy at 500 MHz. The imino proton resonances are assigned by one-dimensional nuclear Overhauser effect spectroscopy. Nonselective T/sub 1/ inversion-recovery experiments are used to determine exchangeable proton lifetimes and to compare helix stability and dynamics of the three duplexes. An extra adenosine flanking the internal G-C base pairs has a strongly localized effect on helix stability, but the destabilizing effect of an extra cytidine in a C tract is delocalized over the entire G-C run. These data lead to the conclusion that the position of the bulge migrates along the run in the fast-exchange limit on the NMR time scale. Rapid migration of the bulge defect in homopolymeric sequences may help rationalize both frame-shift mutagenesis and translational frame shifting. The authors estimate that the unfavorable free energy of a localized bulge defect is 2.9-3.2 kcal/mol, in good agreement with earlier estimates for RNA helices.

  2. The protons and electrons trapped in the Jovian dipole magnetic field region and their interaction with Io

    NASA Technical Reports Server (NTRS)

    Simpson, J. A.; Hamilton, D. C.; Mckibben, R. B.; Mogro-Campero, A.; Pyle, K. R.; Tuzzolino, A. J.

    1974-01-01

    Detailed analysis of electrons equal to or greater than 3 MeV and of protons 0.5 to 1.8 MeV and equal to or greater than 35 MeV for both the inbound and the outbound passes of the Pioneer 10 spacecraft. Conclusive evidence is obtained that the trapped radiation in Jupiter's inner magnetosphere is maintained and supplied by inward diffusion from the outer regions of the trapped radiation zone. It is shown that the time required for isotropization of an anisotropic flux by pitch angle scattering inside L approximately equal to 6 is long in comparison with the time required for particles to diffuse inward from L approximately equal to 6 to L approximately equal to 3, that the high-energy protons were not injected at high energies by the Crand (cosmic ray albedo neutron decay) process but were accelerated in the magnetosphere of Jupiter, and that the main conclusions of this analysis are unaffected by use of either the D sub 1 or the D sub 2 magnetic field models. Theoretical studies of the capture of trapped electrons and protons by Io have been carried out, and it is found that the probability of capture by Io depends strongly upon the particle species and kinetic energy.

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

    PubMed

    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.

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

    PubMed Central

    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. Effects of magnetic non-linearities on a stored proton beam and their implications for superconducting storage rings

    SciTech Connect

    Cornacchia, M.; Evans, L.

    1985-06-01

    A nonlinear lens may be used to study the effect of high-order multipolar field imperfections on a stored proton beam. Such a nonlinear lens is particulary suitable to simulate field imperfections of the types encountered in coil dominated superconducting magnets. We have studied experimentally at the SPS the effect of high order (5th and 8th) single isolated resonances driven by the nonlinear lens. The width of these resonances is of the order one expects to be caused by field errors in superconducting magnets of the SSC type. The experiment shows that, in absence of tune modulation, these resonances are harmless. Slow crossings of the resonance, on the other hand, have destructive effects on the beam, much more so than fast crossings caused by synchrotron oscillations. In the design of future storage rings, sources of low-frequency tune modulation should be avoided as a way to reduce the harmful effects of high order multipolar field imperfection.

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Characterization of heteronuclear decoupling through proton spin dynamics in solid-state nuclear magnetic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    De Paëpe, Gaël; Eléna, Bénédicte; Emsley, Lyndon

    2004-08-01

    The work presented here aims at understanding the performance of phase modulated heteronuclear decoupling sequences such as Cosine Modulation or Two Pulse Phase Modulation. To that end we provide an analytical description of the intrinsic behavior of Cosine Modulation decoupling with respect to radio-frequency-inhomogeneity and the proton-proton dipolar coupling network. We discover through a Modulation Frame average Hamiltonian analysis that best decoupling is obtained under conditions where the heteronuclear interactions are removed but notably where homonuclear couplings are recoupled at a homonuclear Rotary Resonance (HORROR) condition in the Modulation Frame. These conclusions are supported by extensive experimental investigations, and notably through the introduction of proton nutation experiments to characterize spin dynamics in solids under decoupling conditions. The theoretical framework presented in this paper allows the prediction of the optimum parameters for a given set of experimental conditions.

  8. Findings of proton magnetic resonance spectometry in the dorsolateral prefrontal cortex in adolescents with first episodes of psychosis.

    PubMed

    Zabala, Arantzazu; Sánchez-González, Javier; Parellada, Mara; Moreno, Dolores María; Reig, Santiago; Burdalo, María Teresa; Robles, Olalla; Desco, Manuel; Arango, Celso

    2007-10-15

    Knowledge of the neurobiology of early onset psychosis is limited. We used proton magnetic resonance spectroscopy to investigate the possible existence of dorsolateral prefrontal brain biochemical abnormalities in adolescents with psychosis and to determine possible differential effects related to specific psychotic diagnoses. We measured the ratios of N-acetyl-aspartate (NAA), choline (Cho), and creatine (Cr) to water in two groups of adolescents with a first episode of psychosis (schizophrenia n=8; non-schizophrenia n=15) and in 32 healthy controls matched for age, gender, and years of education. Proton magnetic resonance spectroscopy at 1.5 T was used to study two 6.75-cc voxels placed in the left and right dorsolateral prefrontal region. The schizophrenia patients presented statistically significant reductions in NAA/water levels in the left dorsolateral prefrontal voxel as compared with non-schizophrenia patients and healthy controls. No significant differences were detected between groups for NAA/water in the right dorsolateral prefrontal voxel or for Cho/water and Cr/water levels in any hemisphere. A reduction of the NAA/water level in the left dorsolateral prefrontal region may be selectively present at the onset of psychosis during adolescence in patients who later progress to schizophrenia, but not in those who later progress to other psychotic disorders.

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

    PubMed

    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.

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

    PubMed Central

    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

  11. Investigation of Magnetic Field Geometry in Exploding Wire Z-Pinches via Proton Deflectometry

    NASA Astrophysics Data System (ADS)

    Mariscal, Derek; Beg, Farhat; Wei, Mingsheng; Chittenden, Jeremy; Presura, Radu

    2012-10-01

    It is often difficult to determine the configuration of B-fields within z-pinch plasma systems. Typical laser probing diagnostics are limited by the critical density, and electrical diagnostics are prone to failure as well as perturbation of the system. The use of proton beams launched by high intensity lasers, and the subsequent tracking of their deflected trajectories, will enable access to field measurements in previously inaccessible plasma densities.The experimental testing of this method is performed at the Nevada Test Facility (NTF) using the 10J 0.3ps Leopard laser coupled to the 1.6MA ZEBRA pulsed power generator. MHD simulations of the z-pinch plasmas are performed with the 3D resistive MHD code, GORGON. Protons are then injected and tracked through the plasma using the 3D PIC Large Scale Plasma code in order to produce possible proton image plane data. The first computational demonstration of protons propagating through single wire and x-pinch plasmas, along with comparison to recent experimental data will be presented.

  12. Structural Determination of Biomolecular Interfaces by Nuclear Magnetic Resonance of Proteins with Reduced Proton Density

    PubMed Central

    Ferrage, Fabien; Dutta, Kaushik; Shekhtman, Alexander; Cowburn, David

    2013-01-01

    Protein interactions are important for understanding many molecular mechanisms underlying cellular processes. So far, interfaces between interacting proteins have been characterized by NMR spectroscopy mostly by using chemical shift perturbations and cross-saturation via intermolecular cross-relaxation. Although powerful, these techniques cannot provide unambiguous estimates of intermolecular distances between interacting proteins. Here, we present an alternative approach, called REDSPRINT (REDduced/Standard PRoton density INTerface identification), to map protein interfaces with greater accuracy by using multiple NMR probes. Our approach is based on monitoring the cross-relaxation from a source protein (or from an arbitrary ligand that need not be a protein) with high proton density to a target protein (or other biomolecule) with low proton density using isotope-filtered nuclear Overhauser spectroscopy (NOESY). This methodology uses different isotropic labeling for the source and target proteins to identify the source-target interface and also determine the proton density of the source protein at the interface for protein-protein or protein-ligand docking. The utility of this technique, including a method for direct determination of the protein surface, is demonstrated for two different protein-protein complexes. PMID:20372977

  13. Amide proton transfer imaging with improved robustness to magnetic field inhomogeneity and magnetization transfer asymmetry using Saturation with Frequency Alternating RF Irradiation (SAFARI)

    PubMed Central

    Scheidegger, Rachel; Vinogradov, Elena; Alsop, David C

    2011-01-01

    Amide proton transfer (APT) imaging has shown promise as an indicator of tissue pH and as a marker for brain tumors. Sources of error in APT measurements include direct water saturation, and magnetization transfer (MT) from membranes and macromolecules. These are typically suppressed by post-processing asymmetry analysis. However, this approach is strongly dependent on B0 homogeneity and can introduce additional errors due to intrinsic MT asymmetry, aliphatic proton features opposite the amide peak, and radiation damping-induced asymmetry. Although several methods exist to correct for B0 inhomogeneity, they tremendously increase scan times and do not address errors induced by asymmetry of the z-spectrum. In this paper, a novel saturation scheme - saturation with frequency alternating RF irradiation (SAFARI) - is proposed in combination with a new magnetization transfer ratio (MTR) parameter designed to generate APT images insensitive to direct water saturation and MT, even in the presence of B0 inhomogeneity. The feasibility of the SAFARI technique is demonstrated in phantoms and in the human brain. Experimental results show that SAFARI successfully removes direct water saturation and MT contamination from APT images. It is insensitive to B0 offsets up to 180Hz without using additional B0 correction, thereby dramatically reducing scanning time. PMID:21608029

  14. In vivo (1)H-MRS hepatic lipid profiling in nonalcoholic fatty liver disease: an animal study at 9.4 T.

    PubMed

    Lee, Yunjung; Jee, Hee-Jung; Noh, Hyungjoon; Kang, Geun-Hyung; Park, Juyeun; Cho, Janggeun; Cho, Jee-Hyun; Ahn, Sangdoo; Lee, Chulhyun; Kim, Ok-Hee; Oh, Byung-Chul; Kim, Hyeonjin

    2013-09-01

    The applicability of the in vivo proton magnetic resonance spectroscopy hepatic lipid profiling (MR-HLP) technique in nonalcoholic fatty liver disease was investigated. Using magnetic resonance spectroscopy, the relative fractions of diunsaturated (fdi), monounsaturated (fmono), and saturated (fsat) fatty acids as well as total hepatic lipid content were estimated in the livers of 8 control and 23 CCl4-treated rats at 9.4 T. The mean steatosis, necrosis, inflammation, and fibrosis scores of the treated group were all significantly higher than those of the control group (P < 0.01). There was a strong correlation between the histopathologic parameters and the MR-HLP parameters (r = 0.775, P < 0.01) where both steatosis and fibrosis are positively correlated with fmono and negatively correlated with fdi. Both necrosis and inflammation, however, were not correlated with any of the MR-HLP parameters. Hepatic lipid composition appears to be changed in association with the severity of steatosis and fibrosis in nonalcoholic fatty liver disease, and these changes can be depicted in vivo by using the MR-HLP method at 9.4 T. Thus, while it may not likely be that MR-HLP helps differentiate between steatohepatitis in its early stages and simple steatosis, these findings altogether are in support of potential applicability of in vivo MR-HLP at high field in nonalcoholic fatty liver disease.

  15. Magnetic susceptibility and spin dynamics of a polyoxovanadate cluster: A proton NMR study of a model spin tetramer

    NASA Astrophysics Data System (ADS)

    Procissi, D.; Shastri, A.; Rousochatzakis, I.; Al Rifai, M.; Kögerler, P.; Luban, M.; Suh, B. J.; Borsa, F.

    2004-03-01

    We report susceptibility and nuclear magnetic resonance (NMR) measurements in a polyoxovanadate compound with formula (NHEt)3[VIV8VV4As8O40(H2O)]ṡH2O≡{V12}. The magnetic properties can be described by considering only the central square of localized V4+ ions and treated by an isotropic Heisenberg Hamiltonian of four intrinsic spins 1/2 coupled by nearest-neighbor antiferromagnetic interaction with J˜17.6 K. In this simplified description the ground state is nonmagnetic with ST=0. The 1H NMR linewidth (full width at half maximum) data depend on both the magnetic field and temperature, and are explained by the dipolar interaction between proton nuclei and V4+ ion spins. The behavior of the nuclear spin-lattice relaxation rate T-11 in the temperature range (4.2 300 K) is similar to that of χT vs T and it does not show any peak at low temperatures contrary to previous observations in antiferromagnetic rings with larger intrinsic spins. The results are explained by using the general features of the Moriya formula and by introducing a single T-independent broadening parameter for the electronic spin system. From the exponential T dependence of T-11 at low T (2.5 Kproton T-11 deviates from the exponential decrease indicating the presence of a small, almost temperature independent, but strongly field dependent, nuclear relaxation contribution, which we will investigate in detail in the near future.

  16. Usefulness of quantitative peritumoural perfusion and proton spectroscopic magnetic resonance imaging evaluation in differentiating brain gliomas from solitary brain metastases.

    PubMed

    Sparacia, Gianvincenzo; Gadde, Judith A; Iaia, Alberto; Sparacia, Benedetta; Midiri, Massimo

    2016-06-01

    The purpose of our study was to evaluate whether peritumoural perfusion weighted and proton spectroscopic magnetic resonance imaging can be used in differentiating between primary gliomas and solitary metastases. Ten low-grade gliomas, eight high-grade gliomas and 10 metastases were prospectively evaluated with magnetic resonance imaging, dynamic susceptibility contrast enhanced perfusion imaging and single-voxel proton magnetic resonance spectroscopy before surgical resection or stereotactic biopsy. Maximal relative cerebral blood volume values were calculated drawing three regions of interest of 2 cm(2) in the non-enhancing peritumoural areas. Maximal relative cerebral blood volume values were normalised to that of contralateral normal-appearing white matter. Maximal choline/creatine ratios were calculated from three voxels of 10 cm(3) placed in the peritumoural areas defined as non-enhancing peritumoural white matter surrounding the tumour. The tumour grade presumed with these values was compared to histopathological grading. Differences in the study parameters between groups were assessed using the Mann-Whitney test. A receiver operating characteristic analysis was performed to determine cut-off values. A clear relative cerebral blood volume cut-off value of 1.88 was detected for differentiating low-grade gliomas from high-grade gliomas. A clear relative cerebral blood volume cut-off value of 1.20 was detected for differentiation of metastases from gliomas. The differences in the choline/creatine ratios in the peritumoural regions of high-grade gliomas and of solitary metastasis were statistically significant (P < 0.001) but a clear cut-off value was not found. Our preliminary data support the hypothesis that peritumoural perfusion-weighted imaging can assist in preoperative differentiation between a glioma and a solitary metastasis. © The Author(s) 2016.

  17. Desipramine attenuates forced swim test-induced behavioral and neurochemical alterations in mice: an in vivo(1)H-MRS study at 9.4T.

    PubMed

    Kim, Sang-Young; Lee, Yun-Jung; Kim, Hyeonjin; Lee, Do-Wan; Woo, Dong-Cheol; Choi, Chi-Bong; Chae, Jeong-Ho; Choe, Bo-Young

    2010-08-12

    The forced swim test (FST) is a behavioral paradigm that is predicative of antidepressant activity in rodents. The objective of this study was to examine the effects of desipramine (DMI) pretreatment on behavioral and regional neurochemical responses in the left dorsolateral prefrontal cortex (DLPFC) and hippocampus of mice exposed to the FST using proton magnetic resonance spectroscopy ((1)H-MRS). An ultra short echo stimulated echo acquisition (STEAM) localization sequence (TR/TM/TE=5000/20/2.2ms) was used to measure in vivo proton spectra from the left DLPFC (voxel volume: 7microl) and hippocampus (6microl) of C57BL/6 mice at 9.4T and acquired proton spectra post-processed offline with LCModel. The FST induced significant increase of glutamate (Glu) and myo-inositol (mIns) concentrations in the left DLPFC and hippocampus, respectively. In addition, creatine+phosphocreatine (Cr+PCr) concentrations in the left DLPFC were significantly decreased as compared to control. The metabolic alterations induced by the FST were reverted to level similar to control by acute DMI administration. Our results suggest that glutamatergic activity and glial cell dysfunction may contribute to the pathophysiological mechanisms underlying depression and that modulation of synaptic neurotransmitter concentrations represents a potential target for antidepressant drug development.

  18. Study of anisotropy in nuclear magnetic resonance relaxation times of water protons in skeletal muscle.

    PubMed Central

    Kasturi, S R; Chang, D C; Hazlewood, C F

    1980-01-01

    The anisotropy of the spin-lattice relaxation time (T1) and the spin-spin relaxation times (T2) of water protons in skeletal muscle tissue have been studied by the spin-echo technique. Both T1 and T2 have been measured for the water protons of the tibialis anterior muscle of mature male rats for theta = 0, 55, and 90 degrees, where theta is the orientation of the muscle fiber with respect to the static field. The anisotropy in T1 and T2 has been measured at temperatures of 28, -5 and -10 degrees C. No significant anisotropy was observed in the T1 of the tissue water, while an average anisotropy of approximately 5% was observed in T2 at room temperature. The average anisotropy of T2 at -5 and -10 degrees C was found to be approximately 2 and 1.3%, respectively. PMID:6266530

  19. Novel generation of pH indicators for proton magnetic resonance spectroscopic imaging.

    PubMed

    Soler-Padrós, Jordi; Pérez-Mayoral, Elena; Domínguez, Laura; López-Larrubia, Pilar; Soriano, Elena; Marco-Contelles, José Luis; Cerdan, Sebastian; Ballesteros, Paloma

    2007-09-06

    We describe the synthesis of 1,omega-di-1H-imidazoles 2 and 3, derived from l-threitol and d-mannitol, respectively, showing suitable magnetic and toxicological properties, as novel extracellular pH indicators for 1H spectroscopic imaging by magnetic resonance methods.

  20. In vivo proton magnetic resonance spectroscopy of liver metabolites in non-alcoholic fatty liver disease in rats: T2 relaxation times in methylene protons.

    PubMed

    Song, Kyu-Ho; Baek, Hyeon-Man; Lee, Do-Wan; Choe, Bo-Young

    2015-10-01

    The aim of this study was to evaluate the transverse relaxation time of methylene resonance as compared to other lipid resonances. The examinations were performed using a 3.0 T scanner with a point-resolved spectroscopy (PRESS) sequence. Lipid relaxation time in a lipid phantom filled with canola oil was estimated with a repetition time (TR) of 6000ms and echo time (TE) of 40-550ms. For in vivo proton magnetic resonance spectroscopy ((1)H-MRS), eight male Sprague-Dawley rats were given free access to a normal-chow (NC) and another eight male Sprague-Dawley rats were given free access to a high-fat (HF) diet. Both groups drank water ad libitum. T2 measurements in the rats' livers were conducted at a fixed TR of 6000ms and TE of 40-220ms. Exponential curve fitting quality was calculated through the coefficients of determination (R(2)). Chemical analyses of the phantom and livers were not performed, but T2 decay curves were acquired. The T2 relaxation time of methylene resonance was estimated as follows: NC rats, 37.1±4.3ms; HF rats, 31.4±1.8ms (p<0.05). The extrapolated M0 values were higher in HF rats than in NC rats (p<0.005). This study of (1)H MRS led to sufficient spectral resolution and signal-to-noise ratio differences to characterize the T2 relaxation times of methylene resonance. (1)H MRS relaxation times may be useful for quantitative characterization of various liver diseases, including fatty liver disease.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  3. Proton nuclear magnetic resonance measurement of p-boronophenylalanine (BPA): A therapeutic agent for boron neutron capture therapy

    PubMed Central

    Zuo, C. S.; Prasad, P. V.; Busse, Paul; Tang, L.; Zamenhof, R. G.

    2015-01-01

    Noninvasive in vivo quantitation of boron is necessary for obtaining pharmacokinetic data on candidate boronated delivery agents developed for boron neutron capture therapy (BNCT). Such data, in turn, would facilitate the optimization of the temporal sequence of boronated drug infusion and neutron irradiation. Current approaches to obtaining such pharmacokinetic data include: positron emission tomography employing F-18 labeled boronated delivery agents (e.g., p-boronophenylalanine), ex vivo neutron activation analysis of blood (and very occasionally tissue) samples, and nuclear magnetic resonance (NMR) techniques. In general, NMR approaches have been hindered by very poor signal to noise achieved due to the large quadrupole moments of B-10 and B-11 and (in the case of B-10) very low gyromagnetic ratio, combined with low physiological concentrations of these isotopes under clinical conditions. This preliminary study examines the feasibility of proton NMR spectroscopy for such applications. We have utilized proton NMR spectroscopy to investigate the detectability of p-boronophenylalanine fructose (BPA-f) at typical physiological concentrations encountered in BNCT. BPA-f is one of the two boron delivery agents currently undergoing clinical phase-I/II trials in the U.S., Japan, and Europe. This study includes high-resolution 1H spectroscopic characterization of BPA-f to identify useful spectral features for purposes of detection and quantification. The study examines potential interferences, demonstrates a linear NMR signal response with concentration, and presents BPA NMR spectra in ex vivo blood samples and in vivo brain tissues. PMID:10435522

  4. Early identification of hypoxic-ischemic encephalopathy by combination of magnetic resonance (MR) imaging and proton MR spectroscopy

    PubMed Central

    Guo, Lili; Wang, Dehang; Bo, Genji; Zhang, Hui; Tao, Weijing; Shi, Ying

    2016-01-01

    Brain damage following a perinatal hypoxic-ischemic encephalopathy (HIE) can be diagnosed by different techniques. The aim of the present study was to combine magnetic resonance (MR) imaging with proton MR spectroscopy in HIE diagnosis and to evaluate their correlation with outcome. A prospective observational cohort study was performed between February 2012 and February 2013. Consecutive newborns, 24 full-term neonates with HIE (mild to moderate and severe group) and 5 normal neonates, were included. Two sequential MR studies were performed; a conventional MR imaging for observation in T1 weighted image (WI) and T2WI, and proton MR spectroscopy for observation in the left or right basal ganglia and thalamus. MR images were assessed and scored by two neuroradiologists who were blinded to the clinical condition of the infants. The mild to moderate group (n=13) and severe group (n=11) were similar in the visualization of punctate hyperintensity lesions on T1WI and brain edema on T2WI. The differences of N-acetylaspartate/creatine (Cr), choline/Cr and lactate/Cr in the basal ganglia and thalamus in the HIE group were significantly different (P<0.05) compared with the control group, while no significant difference was identified between the mild to moderate and severe group (P>0.05). In conclusion, MR spectroscopy is a complementary tool for the diagnosis of HIE. PMID:27882082

  5. Early identification of hypoxic-ischemic encephalopathy by combination of magnetic resonance (MR) imaging and proton MR spectroscopy.

    PubMed

    Guo, Lili; Wang, Dehang; Bo, Genji; Zhang, Hui; Tao, Weijing; Shi, Ying

    2016-11-01

    Brain damage following a perinatal hypoxic-ischemic encephalopathy (HIE) can be diagnosed by different techniques. The aim of the present study was to combine magnetic resonance (MR) imaging with proton MR spectroscopy in HIE diagnosis and to evaluate their correlation with outcome. A prospective observational cohort study was performed between February 2012 and February 2013. Consecutive newborns, 24 full-term neonates with HIE (mild to moderate and severe group) and 5 normal neonates, were included. Two sequential MR studies were performed; a conventional MR imaging for observation in T1 weighted image (WI) and T2WI, and proton MR spectroscopy for observation in the left or right basal ganglia and thalamus. MR images were assessed and scored by two neuroradiologists who were blinded to the clinical condition of the infants. The mild to moderate group (n=13) and severe group (n=11) were similar in the visualization of punctate hyperintensity lesions on T1WI and brain edema on T2WI. The differences of N-acetylaspartate/creatine (Cr), choline/Cr and lactate/Cr in the basal ganglia and thalamus in the HIE group were significantly different (P<0.05) compared with the control group, while no significant difference was identified between the mild to moderate and severe group (P>0.05). In conclusion, MR spectroscopy is a complementary tool for the diagnosis of HIE.

  6. Oral glycine administration increases brain glycine/creatine ratios in men: a proton magnetic resonance spectroscopy study

    PubMed Central

    Kaufman, Marc J.; Prescot, Andrew P.; Ongur, Dost; Evins, A. Eden; Barros, Tanya L.; Medeiros, Carissa L.; Covell, Julie; Wang, Liqun; Fava, Maurizio; Renshaw, Perry F.

    2009-01-01

    Oral high-dose glycine administration has been used as an adjuvant treatment for schizophrenia to enhance glutamate neurotransmission and mitigate glutamate system hypofunction thought to contribute to the disorder. Prior studies in schizophrenia subjects documented clinical improvements after 2 weeks of oral glycine administration, suggesting that brain glycine levels are sufficiently elevated to evoke a clinical response within that time frame. However, no human study has reported on brain glycine changes induced by its administration. We utilized a noninvasive proton magnetic resonance spectroscopy (1H-MRS) technique termed echo time-averaged (TEAV) 1H-MRS, which permits noninvasive quantification of brain glycine in vivo, to determine whether 2 weeks of oral glycine administration (peak dose of 0.8g/kg/day) increased brain glycine/creatine (Gly/Cr) ratios in 11 healthy adult men. In scans obtained 17 hours after the last glycine dose, brain (Gly/Cr) ratios were significantly increased. The data indicate that it is possible to measure brain glycine changes with proton spectroscopy. Developing a more comprehensive understanding of human brain glycine dynamics may lead to optimized use of glycine site agonists and glycine transporter inhibitors to treat schizophrenia, and possibly to treat other disorders associated with glutamate system dysfunction. PMID:19556112

  7. Comparative proton nuclear magnetic resonance studies of amantadine complexes formed in aqueous solutions with three major cyclodextrins.

    PubMed

    Lis-Cieplak, Agnieszka; Sitkowski, Jerzy; Kolodziejski, Waclaw

    2014-01-01

    Host-guest complexes of alpha-, beta-, and gamma-cyclodextrins (α-CD, β-CD, and γ-CD, respectively) with amantadine (1-aminoadamantane, AMA; an antiviral agent) were characterized in aqueous solutions using proton nuclear magnetic resonance (NMR) spectroscopy. Host-guest molecular interactions were manifested by changes in the chemical shifts of AMA protons. NMR Job's plots showed that the stoichiometry of all the studied complexes was 1:1. Two-dimensional T-ROESY experiments demonstrated that the complexes were formed by different degrees of incorporation of the adamantyl group of AMA into the CD cavity. The mode of AMA binding was proposed. The AMA molecule came into the α-CD cavity (the smallest size) or β-CD cavity (the intermediate size) through its wide entrance to become shallowly or deeply accommodated, respectively. In the complex of AMA with γ-CD (the largest cavity size), the adamantyl group was also quite deeply inserted into the CD cavity, but it arrived there through the narrow cavity entrance. It was found that the adamantyl group of AMA was best accommodated by the β-CD cavity. The binding constants Kaa of the studied complexes (in M(-1) ), determined from DOSY NMR, were fairly high; their values in an ascending order were: α-CD (183) < γ-CD (306) ≪ β-CD (5150).

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

    SciTech Connect

    Nettesheim, D.G.; Klevit, R.E.; Drobny, G.; Watt, D.D.; Krishna, N.R. )

    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.

  9. Proton nuclear magnetic resonance assignments and secondary structure determination of the Co1E1 rop (rom) protein

    SciTech Connect

    Eberle, W. European Molecular Biology Lab., Heidelberg ); Klaus, W. ); Cesareni, G. ); Sander, C. ); Roesch, P. )

    1990-08-14

    The complete resonance assignment of the Co1E1 rop (rom) protein at pH 2.3 was obtained by two-dimensional (2D) proton nuclear magnetic resonance spectroscopy ({sup 1}H NMR) at 500 and 600 MHz using through-bond and through-space connectivities. Sequential assignments and elements of regular secondary structure were deduced by analysis of nuclear Overhauser enhancement spectroscopy (NOESY) experiments and {sup 3}J{sub HN{alpha}} coupling constants. One 7.2-kDa monomer of the homodimer consists of two antiparallel helices connected by a hairpin loop at residue 31. The C-terminal peptide consisting of amino acids 59-63 shows no stable conformation. The dimer forms a four-helix bundle with opposite polarization of neighboring elements in agreement with the x-ray structure.

  10. Brain ketones detected by proton magnetic resonance spectroscopy in an infant with Ohtahara syndrome treated with ketogenic diet.

    PubMed

    Cecil, Kim M; Mulkey, Sarah B; Ou, Xiawei; Glasier, Charles M

    2015-01-01

    Atypical resonances on proton magnetic resonance spectroscopy (MRS) examinations are occasionally found in children undergoing a metabolic evaluation for neurological conditions. While a radiologist's first instinct is to suspect a pathological metabolite, usually the origin of the resonance arises from an exogenous source. We report the appearance of distinct resonances associated with a ketogenic diet in a male infant presenting with Ohtahara syndrome. These resonances can be confused in interpretation with lactate and glutamate. To confirm assignments, the basis set for quantification was supplemented with simulations of β-hydroxybutyrate, acetone and acetoacetate in LCModel spectroscopy processing software. We were able to quantitate the levels of end products of a ketogenic diet and illustrate how to distinguish these resonances.

  11. NOTE: Detection limits for ferrimagnetic particle concentrations using magnetic resonance imaging based proton transverse relaxation rate measurements

    NASA Astrophysics Data System (ADS)

    Pardoe, H.; Chua-anusorn, W.; St. Pierre, T. G.; Dobson, J.

    2003-03-01

    A clinical magnetic resonance imaging (MRI) system was used to measure proton transverse relaxation rates (R2) in agar gels with varying concentrations of ferrimagnetic iron oxide nanoparticles in a field strength of 1.5 T. The nanoparticles were prepared by coprecipitation of ferric and ferrous ions in the presence of either dextran or polyvinyl alcohol. The method of preparation resulted in loosely packed clusters (dextran) or branched chains (polyvinyl alcohol) of particles containing of the order of 600 and 400 particles, respectively. For both methods of particle preparation, concentrations of ferrimagnetic iron in agar gel less than 0.01 mg ml-1 had no measurable effect on the value of R2 for the gel. The results indicate that MRI-based R2 measurements using 1.5 T clinical scanners are not quite sensitive enough to detect the very low concentrations of nanoparticulate biogenic magnetite reported in human brain tissue.

  12. Proton radiography of dynamic electric and magnetic fields in laser-produced high-energy-density plasmas

    SciTech Connect

    Li, C. K.; Seguin, F. H.; Frenje, J. A.; Manuel, M.; Casey, D.; Sinenian, N.; Petrasso, R. D.; Amendt, P. A.; Landen, O. L.; Rygg, J. R.; Town, R. P. J.; Betti, R.; Meyerhofer, D. D.; Delettrez, J.; Knauer, J. P.; Marshall, F.; Sangster, T. C.; Smalyuk, V. A.; Soures, J. M.; Shvarts, D.

    2009-05-15

    Time-gated, monoenergetic-proton radiography provides unique measurements of the electric (E) and magnetic (B) fields produced in laser-foil interactions and during the implosion of inertial-confinement-fusion capsules. These experiments resulted in the first observations of several new and important features: (1) observations of the generation, decay dynamics, and instabilities of megagauss B fields in laser-driven planar plastic foils, (2) the observation of radial E fields inside an imploding capsule, which are initially directed inward, reverse direction during deceleration, and are likely related to the evolution of the electron pressure gradient, and (3) the observation of many radial filaments with complex electromagnetic field striations in the expanding coronal plasmas surrounding the capsule. The physics behind and implications of such observed fields are discussed.

  13. Proton radiography of dynamic electric and magnetic fields in laser-produced high-energy-density plasmas

    SciTech Connect

    Li, C. K.; Séguin, F. H.; Frenje, J. A.; Manuel, M.; Casey, D.; Sinenian, N.; Petrasso, R. D.; Amendt, P. A.; Landen, O. L.; Rygg, J. R.; Town, R. P. J.; Betti, R.; Delettrez, J.; Knauer, J. P.; Marshall, F.; Meyerhofer, D. D.; Sangster, T. C.; Shvarts, D.; Smalyuk, V. A.; Soures, J. M.; Back, C. A.; Kilkenny, J. D.; Nikroo, A.

    2009-01-01

    Time-gated, monoenergetic-proton radiography provides unique measurements of the electric (E) and magnetic (B) fields produced in laser-foil interactions and during the implosion of inertial-confinement-fusion capsules. These experiments resulted in the first observations of several new and important features: (1) observations of the generation, decay dynamics, and instabilities of megagauss B fields in laser-driven planar plastic foils, (2) the observation of radial E fields inside an imploding capsule, which are initially directed inward, reverse direction during deceleration, and are likely related to the evolution of the electron pressure gradient, and (3) the observation of many radial filaments with complex electromagnetic field striations in the expanding coronal plasmas surrounding the capsule. The physics behind and implications of such observed fields are discussed.

  14. Angular, spectral, and time distributions of highest energy protons and associated secondary gamma rays and neutrinos propagating through extragalactic magnetic and radiation fields

    SciTech Connect

    Aharonian, F. A.; Kelner, S. R.; Prosekin, A. Yu.

    2010-08-15

    The angular, spectral, and temporal features of the highest energy protons and, accompanying them, secondary neutrinos and synchrotron gamma rays propagating through the intergalactic magnetic and radiation fields are studied using the analytical solutions of the Boltzmann transport equation obtained in the limit of the small-angle and continuous-energy-loss approximation.

  15. 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

    ERIC Educational Resources Information Center

    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…

  16. 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

    ERIC Educational Resources Information Center

    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…

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

    PubMed

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

    2017-01-01

    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. 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. 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. 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.

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

    PubMed Central

    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

  19. Proton NMR study of spin dynamics in the magnetic organic chains M (hfac)3 NITEt (M =Eu3 +,Gd3 + )

    NASA Astrophysics Data System (ADS)

    Mariani, M.; Lascialfari, A.; Caneschi, A.; Ammannato, L.; Gatteschi, D.; Rettori, A.; Pini, M. G.; Cucci, C.; Borsa, F.

    2016-04-01

    In this work, we present a nuclear magnetic resonance (NMR) study of the spin dynamics in the rare-earth-based low-dimensional molecular magnetic chains Eu (hfac) 3NITEt and Gd (hfac) 3NITEt (in short, Eu-Et and Gd-Et). Although both samples are based on the same chemical building block, [(hfac) 3NITEt ] , their magnetic properties change dramatically when the Eu3 + ion, which is nonmagnetic at low temperatures, is substituted by the magnetic Gd3 + ion. The present proton NMR investigation shows that, down to the lowest investigated temperature (T =1.5 K for Gd-Et and T =3 K for Eu-Et), the Eu-Et chain behaves as a one-dimensional Heisenberg model with antiferromagnetic exchange coupling (J =-20 K) between s =1 /2 organic radicals, and has a T -independent exchange frequency (ωe=2.6 ×1012 rad/s). In the Gd-Et chain, in contrast, a competition arises between nearest-neighbor ferromagnetic coupling and next-nearest-neighbor antiferromagnetic coupling; moreover, two phase transitions have previously been found, in agreement with Villain's conjecture: a first transition, at T0=2.2 K, from a high temperature paramagnetic phase to a chiral spin liquid phase, and a second transition, at TN=1.9 K, to a three-dimensional helical spin solid phase. Contrary to the Eu-Et chain (whose three-dimensional ordering temperature is estimated to insurge at very low, TN≈0.3 K), critical spin dynamics effects have been measured in the Gd-Et chain on approaching TN=1.9 K: namely, a divergence of the proton nuclear spin-lattice relaxation rate 1 /T1 , which in turn produces a sudden wipe-out of the NMR signal in a very narrow (Δ T ˜0.04 K) temperature range above TN. Below TN, an inhomogeneous broadening of the NMR line indicates a complete spin freezing. At T0=2.2 K, instead, such critical effects are not observed because NMR measurements probe the two-spin correlation function, while the chiral spin liquid phase transition is associated with a divergence of the four

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

  2. Design of a compact, permanent magnet electron cyclotron resonance ion source for proton and H{sub 2}{sup +} beam production

    SciTech Connect

    Jia Xianlu; Zhang Tianjue; Wang Chuan; Zheng Xia; Yin Zhiguo; Zhong Junqing; Wu Longcheng; Qin Jiuchang; Luo Shan

    2010-02-15

    A 2.45 GHz microwave ion source was developed at China Institute of Atomic Energy (CIAE) for proton beam production of over 60 mA [B.-Q. Cui, Y.-W. Bao, L.-Q. Li, W.-S. Jiang, and R.-W. Wang, Proceedings of the High Current Electron Cyclotron Resonance (ECR) Ion Source for Proton Accelerator, APAC-2001, 2001 (unpublished)]. For various proton beam applications, another 2.45 GHz microwave ion source with a compact structure is designed and will be built at CIAE as well for high current proton beam production. It is also considered to be used for the test of H{sub 2}{sup +} beam, which could be injected into the central region model cyclotron at CIAE, and accelerated to 5 MeV before extraction by stripping. The required ECR magnetic field is supplied by all the permanent magnets rather than electrical solenoids and six poles. The magnetic field distribution provided by this permanent magnets configuration is a large and uniformly volume of ECR zone, with central magnetic field of a magnitude of {approx}875 Gs[T. Taylor and J. S. C. Wills, Nucl. Instrum. Methods Phys. Res. A 309, 37 (1991)]. The field adjustment at the extraction end can be implemented by moving the position of the magnet blocks. The results of plasma, coupling with 2.45 GHz microwave in the ECR zone inside the ion source are simulated by particle-in-cell code to optimize the density by adjusting the magnetic field distribution. The design configuration of the ion source will be summarized in the paper.

  3. Impact of sepsis on CD4 T cell immunity

    PubMed Central

    Cabrera-Perez, Javier; Condotta, Stephanie A.; Badovinac, Vladimir P.; Griffith, Thomas S.

    2014-01-01

    Sepsis remains the primary cause of death from infection in hospital patients, despite improvements in antibiotics and intensive-care practices. Patients who survive severe sepsis can display suppressed immune function, often manifested as an increased susceptibility to (and mortality from) nosocomial infections. Not only is there a significant reduction in the number of various immune cell populations during sepsis, but there is also decreased function in the remaining lymphocytes. Within the immune system, CD4 T cells are important players in the proper development of numerous cellular and humoral immune responses. Despite sufficient clinical evidence of CD4 T cell loss in septic patients of all ages, the impact of sepsis on CD4 T cell responses is not well understood. Recent findings suggest that CD4 T cell impairment is a multipronged problem that results from initial sepsis-induced cell loss. However, the subsequent lymphopenia-induced numerical recovery of the CD4 T cell compartment leads to intrinsic alterations in phenotype and effector function, reduced repertoire diversity, changes in the composition of naive antigen-specific CD4 T cell pools, and changes in the representation of different CD4 T cell subpopulations (e.g., increases in Treg frequency). This review focuses on sepsis-induced alterations within the CD4 T cell compartment that influence the ability of the immune system to control secondary heterologous infections. The understanding of how sepsis affects CD4 T cells through their numerical loss and recovery, as well as function, is important in the development of future treatments designed to restore CD4 T cells to their presepsis state. PMID:24791959

  4. Seasonal and temporal characterization of dissolved organic matter in rainwater by proton nuclear magnetic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Seaton, Pamela J.; Kieber, Robert J.; Willey, Joan D.; Avery, G. Brooks; Dixon, Joshua L.

    2013-02-01

    Dissolved organic carbon in rainwater was concentrated by two separate techniques and characterized by 1H-NMR. The total 1H-NMR integral of lyophilized rainwater was higher in every rain sample than that of C18 solid phase extracted samples and always contained a higher percentage integral in the region of protons bound to carbon atoms singly bound to oxygen (H-C-O), such as alcohols, polyols and carbohydrate-like compounds. C18 extracted samples had higher % integral in the alkyl region, consistent with reverse phase extraction of more hydrophobic components in rainwater. Differences in both the 1H-NMR integration and spectral pattern of lyophilized rainwater samples were especially apparent between spring and winter rains, with spring samples having higher percent carbohydrate (H-C-O) signal and winter rains having higher percent alkyl protons and a spectral pattern consistent with the presence of saturated fatty acids. Spring rains are characterized by lower % Alkyl signal coupled with higher % H-C-O than all other events while marine winter events appear in regions characterized by relatively high % Alkyl and average % H-C-O, consistent with increased abundance of fatty acids or fatty acid oxidation products. The 1H-NMR data presented in this manuscript are important because they provide spectral data relating to the source and chemical characteristics of dissolved organic carbon in rainwater as a function of season and air mass back trajectory.

  5. Rat brain MRI at 16.4T using a capacitively tunable patch antenna in combination with a receive array.

    PubMed

    Shajan, G; Hoffmann, Jens; Balla, Dávid Z; Deelchand, Dinesh K; Scheffler, Klaus; Pohmann, Rolf

    2012-10-01

    For MRI at 16.4T, with a proton Larmor frequency of 698 MHz, one of the principal RF engineering challenges is to generate a spatially homogeneous transmit field over a larger volume of interest for spin excitation. Constructing volume coils large enough to house a receive array along with the subject and to maintain the quadrature symmetry for different loading conditions is difficult at this frequency. This calls for new approaches to RF coil design for ultra-high field MR systems. A remotely placed capacitively tunable patch antenna, which can easily be adjusted to different loading conditions, was used to generate a relatively homogeneous excitation field covering a large imaging volume with a transversal profile similar to that of a birdcage coil. Since it was placed in front of the animal, this created valuable free space in the narrow magnet bore around the subject for additional hardware. To enhance the reception sensitivity, the patch antenna was combined with an actively detunable 3-channel receive coil array. In addition to increased SNR compared to a quadrature transceive surface coil, we were able to get high quality gradient echo and spin-echo images covering the whole rat brain.

  6. SU-E-J-229: Magnetic Resonance Imaging of Small Fiducial Markers for Proton Beam Therapy

    SciTech Connect

    Hu, Y; James, J; Panda, A; Vargas, C; Silva, A; Liu, W; Shen, J; Ding, X; Paden, R; Hanson, J; Wong, W; Schild, S; Bues, M

    2015-06-15

    Purpose: For proton beam therapy, small fiducial markers are preferred for patient alignment due to less interference with the proton beam. Visualizing small fiducial markers can be challenging in MRI. This study intends to investigate MRI imaging protocols for better visualization of small fiducial markers. Methods: Two carbon and two coil-shaped gold markers were placed into a gel phantom. Both carbon markers had a diameter of 1mm and a length of 3mm. Both gold markers had a length of 5mm. One gold marker had a diameter of 0.5mm and the other had a diameter of 0.75mm. T1 VIBE, T2 SPACE, TrueFISP and susceptibility weighted (SW) images were acquired. To improve marker contrast, high spatial resolution was used to reduce partial volume effect. Slice thickness was 1.5mm for all four sequences and in-plane resolution was 0.6mm for TrueFISP, 0.7mm for T1 VIBE, and 0.8mm for T2 SPACE and SW. For comparison purpose, a 3D T1 VIBE image set at 3mm slice thickness and 1.2mm in-plane resolution was also acquired. Results: All markers were visible in all high-resolution image sets. In each image set, marker-induced signal void was the smallest (in diameter) for carbon markers, followed by the 0.5mm gold marker and the largest for the 0.75mm gold marker. The SW images had the largest marker-induced signal void. However, those might be confused by susceptibility-gradient-induced signal voids. T1 VIBE had good visualization of markers with nicely defined edges. T2 SPACE had reasonable visualization of markers but edges were slightly blurred. TrueFISP had good visualization of markers only if they were not masked by banding artifacts. As a comparison, all markers were hardly visible in the standard resolution T1 VIBE images. Conclusion: 3D high-resolution T1 VIBE and SW have great potential in providing good visualization of small fiducial markers for proton beam therapy.

  7. Effect of mica content on pore-size distribution and porosity of sandy sediment using proton nuclear magnetic resonance measurement

    NASA Astrophysics Data System (ADS)

    Kimura, S.

    2015-12-01

    As a part of a Japanese National hydrate research program (MH21, funded by METI), we performed a study on effect of mica content on pore size distribution and porosity of sandy sediment. This study used proton nuclear magnetic resonance (NMR) to measure the pore-size distribution and porosity of specimen to investigate mica content effect in sandy sediment. A mixture of silica sand No. 7 and mica (mica of 0 wt. %, 5 wt. % and 20 wt. %) was used in this study. The median D50 by laser diffraction method was obtained as 215.7 μm of silica sand No. 7 and 278.9 μm of mica. Pore-size distributions of specimens by the distribution of transverse magnetic relaxation time (T2) measurement by NMR were performed for the water-saturated sample under effective confining pressure of 1.0 MPa. The peaks of pore-size distribution curves decreased and showed finer shifts with increasing of mica content. The porosity of silica sand No. 7 specimen was 46.3%, and that of mica 5% and 20 % were 45.9% and 42.2%m, respectively. A change in pore-size distribution and porosity were observed with an increasing ratio of mica.

  8. 7 Tesla proton magnetic resonance spectroscopic imaging in adult X-linked adrenoleukodystrophy

    PubMed Central

    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 < 0.05). Both NAA/Cr and Glu/Cr ratios were lower in AMN patients (p = 0.028 and p = 0.036, respectively) than in controls. There were no significant differences between AMN and female heterozygotes. In cortex, ACALD patients had lower values of NAA/Cr compared to female heterozygotes and controls (p = 0.022). The global MI/Cr ratio demonstrated a significant association with the EDSS (Spearman ρ = 0.66, p = 0.039). Conclusion 7 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

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    Pravdivtsev, Andrey N.; Yurkovskaya, Alexandra V.; Ivanov, Konstantin L.; Vieth, Hans-Martin

    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.

  11. Properties of a large-scale interplanetary loop structure as deduced from low-energy proton anisotropy and magnetic field measurements

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    Correlated particle and magnetic field measurements by the ISEE 3 spacecraft are presented for the loop structure behind the interplanetary traveling shock event of Nov. 12, 1978. Following the passage of the turbulent shock region, strong bidirectional streaming of low-energy protons is observed for approximately 6 hours, corresponding to a loop thickness of about 0.07 AU. This region is also characterized by a low relative variance of the magnetic field, a depressed proton intensity, and a reduction in the magnetic power spectral density. Using quasi-linear theory applied to a slab model, a value of 3 AU is derived for the mean free path during the passage of the closed loop. It is inferred from this observation that the proton regime associated with the loop structure is experiencing scatter-free transport and that either the length of the loop is approximately 3 AU between the sun and the earth or else the protons are being reflected at both ends of a smaller loop.

  12. Properties of a large-scale interplanetary loop structure as deduced from low-energy proton anisotropy and magnetic field measurements

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    Correlated particle and magnetic field measurements by the ISEE 3 spacecraft are presented for the loop structure behind the interplanetary traveling shock event of Nov. 12, 1978. Following the passage of the turbulent shock region, strong bidirectional streaming of low-energy protons is observed for approximately 6 hours, corresponding to a loop thickness of about 0.07 AU. This region is also characterized by a low relative variance of the magnetic field, a depressed proton intensity, and a reduction in the magnetic power spectral density. Using quasi-linear theory applied to a slab model, a value of 3 AU is derived for the mean free path during the passage of the closed loop. It is inferred from this observation that the proton regime associated with the loop structure is experiencing scatter-free transport and that either the length of the loop is approximately 3 AU between the sun and the earth or else the protons are being reflected at both ends of a smaller loop.

  13. Electron-proton spectrometer

    NASA Technical Reports Server (NTRS)

    Winckler, J. R.

    1973-01-01

    An electron-proton spectrometer was designed to measure the geomagnetically trapped radiation in a geostationary orbit at 6.6 earth radii in the outer radiation belt. This instrument is to be flown on the Applications Technology Satellite-F (ATS-F). The electron-proton spectrometer consists of two permanent magnet surface barrier detector arrays and associated electronics capable of selecting and detecting electrons in three energy ranges: (1) 30-50 keV, (2) 150-200 keV, and (3) 500 keV and protons in three energy ranges. The electron-proton spectrometer has the capability of measuring the fluxes of electrons and protons in various directions with respect to the magnetic field lines running through the satellite. One magnet detector array system is implemented to scan between EME north and south through west, sampling the directional flux in 15 steps. The other magnet-detector array system is fixed looking toward EME east.

  14. EXOTIC MAGNETS FOR ACCELERATORS.

    SciTech Connect

    WANDERER, P.

    2005-09-18

    Over the last few years, several novel magnet designs have been introduced to meet the requirements of new, high performance accelerators and beam lines. For example, the FAIR project at GSI requires superconducting magnets ramped at high rates ({approx} 4 T/s) in order to achieve the design intensity. Magnets for the RIA and FAIR projects and for the next generation of LHC interaction regions will need to withstand high doses of radiation. Helical magnets are required to maintain and control the polarization of high energy protons at RHIC. In other cases, novel magnets have been designed in response to limited budgets and space. For example, it is planned to use combined function superconducting magnets for the 50 GeV proton transport line at J-PARC to satisfy both budget and performance requirements. Novel coil winding methods have been developed for short, large aperture magnets such as those used in the insertion region upgrade at BEPC. This paper will highlight the novel features of these exotic magnets.

  15. Optically transmitted and inductively coupled electric reference to access in vivo concentrations for quantitative proton-decoupled ¹³C magnetic resonance spectroscopy.

    PubMed

    Chen, Xing; Pavan, Matteo; Heinzer-Schweizer, Susanne; Boesiger, Peter; Henning, Anke

    2012-01-01

    This report describes our efforts on quantification of tissue metabolite concentrations in mM by nuclear Overhauser enhanced and proton decoupled (13) C magnetic resonance spectroscopy and the Electric Reference To access In vivo Concentrations (ERETIC) method. Previous work showed that a calibrated synthetic magnetic resonance spectroscopy-like signal transmitted through an optical fiber and inductively coupled into a transmit/receive coil represents a reliable reference standard for in vivo (1) H magnetic resonance spectroscopy quantification on a clinical platform. In this work, we introduce a related implementation that enables simultaneous proton decoupling and ERETIC-based metabolite quantification and hence extends the applicability of the ERETIC method to nuclear Overhauser enhanced and proton decoupled in vivo (13) C magnetic resonance spectroscopy. In addition, ERETIC signal stability under the influence of simultaneous proton decoupling is investigated. The proposed quantification method was cross-validated against internal and external reference standards on human skeletal muscle. The ERETIC signal intensity stability was 100.65 ± 4.18% over 3 months including measurements with and without proton decoupling. Glycogen and unsaturated fatty acid concentrations measured with the ERETIC method were in excellent agreement with internal creatine and external phantom reference methods, showing a difference of 1.85 ± 1.21% for glycogen and 1.84 ± 1.00% for unsaturated fatty acid between ERETIC and creatine-based quantification, whereas the deviations between external reference and creatine-based quantification are 6.95 ± 9.52% and 3.19 ± 2.60%, respectively.

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

    PubMed

    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.

  17. Proton nuclear magnetic resonance identification and discrimination of side chain isomers of phytosterols using a lanthanide shift reagent.

    PubMed

    Iida, T; Tamura, T; Matsumoto, T

    1980-03-01

    Proton nuclear magnetic resonance (1H-NMR) spectra at 90 MHz were measured for a number of side chain isomers of phytosterols (sterols with a C8H17 side chain, and delta 24-, 24-methylene, delta 22-, 24-ethylidene, 24-methly, 24-ethyl, 24-methyl-delta 22-, 24-ethyl delta 22-, and 24-ethyl-delta 22,25(27)-sterols) with or without a lanthanide shift reagent, tris[1,1,1,2,2,3,3 - heptafluoro - 7,7 - dimethyloctane - 4,6 - dionato]ytterbium, Yb(fod)3, and the effect of Yb(fod)3 on the side chain methyl protons is discussed. The change of the chemical shifts induced Yb(fod)3 for the side chain methyls was expressed in terms of the induced shift ratios (ISR values), i.e., the ratios of the induced chemical shifts of the respective side chain methyls to that of the fastest moving side chain methyl. The ISR values were sentitive to minor structural and stereochemical differences, but almost independent of ring structures and of substrate concentrations, thus providing confirmatory evidence for the side chain structures. Also, the Yb(fod)3-induced spectral patterns observed in the high-field methyl region bore the fingerprints of the side chain structures. Several isomeric pairs of sterols, which differ only in the geometry of double bonds or the absolute configuration at C-24 in the side chain, i.e., cis- and trans-isomers of delta 22-and 24-ethylidene sterols, 24R/alpha- and 24S/beta-methyl sterols, 24R/alpha- and 24S/beta-ethyl sterols, and 24S/alpha- and 24R/beta-ethyl-delta 22-sterols, could be differentiated from each other under the influence of Yb(fod)3, even though they were measured at 90 MHz.

  18. Multicomponent analysis of radiolytic products in human body fluids using high field proton nuclear magnetic resonance (NMR) spectroscopy

    NASA Astrophysics Data System (ADS)

    Grootveld, Martin C.; Herz, Herman; Haywood, Rachel; Hawkes, Geoffrey E.; Naughton, Declan; Perera, Anusha; Knappitt, Jacky; Blake, David R.; Claxson, Andrew W. D.

    1994-05-01

    High field proton Hahn spin-echo nuclear magnetic resonance (NMR) spectroscopy has been employed to investigate radiolytic damage to biomolecules present in intact human body fluids. γ-Radiolysis of healthy or rheumatoid human serum (5.00 kGy) in the presence of atmospheric O 2 gave rise to reproducible elevations in the concentration of NMR-detectable acetate which are predominantly ascribable to the prior oxidation of lactate to pyruvate by hydroxyl radical (·OH) followed by oxidative decarboxylation of pyruvate by radiolytically-generated hydrogen peroxide (H 2O 2) and/or further ·OH radical. Increases in the serum levels of non-protein-bound, low-molecular-mass components such as citrate and glutamine were also observed subsequent to γ-radiolysis, an observation which may reflect their mobilisation from protein binding-sites by ·OH radical, superoxide anion and/or H 2O 2. Moreover, substantial radiolytically-mediated elevations in the concentration of serum formate were also detectable. In addition to the above modifications, γ-radiolysis of inflammatory knee-joint synovial fluid (SF) generated a low-molecular-mass oligosaccharide species derived from the radiolytic fragmentation of hyaluronate. The radiolytically-mediated production of acetate in SF samples was markedly greater than that observed in serum samples, a consequence of the much higher levels of ·OH radical-scavenging lactate present. Indeed, increases in SF acetate concentration were detectable at doses as low as 48 Gy. We conclude that high field proton NMR analysis provides much useful information regarding the relative radioprotectant abilities of endogenous components and the nature, status and levels of radiolytic products generated in intact biofluids. We also suggest that NMR-detectable radiolytic products with associated toxicological properties (e.g. formate) may play a role in contributing to the deleterious effects observed following exposure of living organisms to sources of

  19. Proton magnetic resonance spectroscopy of the intrinsic tongue muscles in patients with myasthenia gravis with different autoantibodies.

    PubMed

    Lavrnic, Dragana; Dakovic, Marko; Peric, Stojan; Rakocevic-Stojanovic, Vidosava; Basta, Ivana; Marjanovic, Ivan; Stosic-Opincal, Tatjana; Lavrnic, Slobodan

    2011-03-15

    To assess lipid composition of the intrinsic tongue muscles in patients with myasthenia gravis (MG). This study included 15 MG patients with antibodies against muscle-specific kinase (MuSK), 15 matched MG patients with antibodies against acetylcholine receptor (AChR) and 15 matched healthy subjects. Middle posterior region of the tongue was analyzed by single voxel point-resolved proton magnetic resonance spectroscopy (MRS) using 1.5T MRI scanner. MRS obtained from subject with AChR MG showed a broad resonance arising from methylene groups of lipids (PMN) with no observable shoulder attributed to methyl groups (PML). Full-width at half maximum (FWHM) of PMN+PML peak showed higher value in patients with AChR MG in comparison to healthy subjects and MuSK MG patients (p<0.05). In patients with MuSK MG, the shape and FWHM of PMN+PML peak was similar as in healthy subjects (p>0.05), with tendency toward increased ratio between PMN and resonance from vinyl protons of lipids (PV). In both AChR and MuSK MG, total creatine resonance (creatine+phosphocreatine, CP) was almost absent with significant increase of PMN/CP ratio in comparison to healthy subjects (p<0.05). MRS is useful in revealing muscle lipid composition in MG. In patients with AChR MG, MRS showed increased lipid content in the tongue muscles due to the lipid migration from intra- to extramyocellular space. Finding in patients with MuSK MG might reflect intramyocellular lipid deposition in the tongue. CP decrease in tongue muscles indicated impairment of oxidative metabolism in both AChR MG and MuSK MG. Copyright © 2010. Published by Elsevier B.V.

  20. Neurodegenerative evidences during early onset of depression in CMS rats as detected by proton magnetic resonance spectroscopy at 7 T.

    PubMed

    Hemanth Kumar, B S; Mishra, Sushanta Kumar; Rana, Poonam; Singh, Sadhana; Khushu, Subash

    2012-06-15

    Depression is a complex psychiatric disorder characterized by anhedonia and feeling of sadness and chronic mild stress (CMS) seems to be a valuable animal model of depression. CMS animal model was induced and validated using behavioral studies. In the present study we investigated the neuro-metabolite changes occurring in prefrontal cortex and hippocampus during the onset of depression, in CMS rat model using in vivo proton magnetic resonance spectroscopy ((1)H MRS) at field strength of 7 T. Results showed that CMS caused depression-like behavior in rats, as indicated by the decrease in sucrose consumption and locomotor activity. (1)H MRS was performed in both control and CMS rats (n=10, in each group) and the quantitative assessment of the neurometabolites was done using LC model. Relative concentrations of all the metabolites along with the macromolecules were calculated for analysis. The results revealed a significant decrease of glutamate (Glu), glutamine (Gln), NAA+NAAG, Glx and GABA levels in both hippocampus and prefrontal cortex of CMS animals and an elevated level of myo-ionisitol (mI) and taurine (Tau) was observed only in hippocampus. These metabolite fluctuations revealed by proton MRS indicate that there might be change in the neuronal integrity of the glial cells and neurons within prefrontal cortex and hippocampus in CMS model of depression. The present study also suggests that there may be a degenerative process concerning the brain morphology in the CMS rats. The overall finding using (1)H MRS suggests that, there might be a major role of the glia and neuron in the onset of depression. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Hydrogenated Graphenes by Birch Reduction: Influence of Electron and Proton Sources on Hydrogenation Efficiency, Magnetism, and Electrochemistry.

    PubMed

    Eng, Alex Yong Sheng; Sofer, Zdeněk; Huber, Štěpán; Bouša, Daniel; Maryško, Miroslav; Pumera, Martin

    2015-11-16

    Interest in chemical functionalisation of graphenes today is largely driven by associated changes to its physical and material properties. Functionalisation with hydrogen was employed to obtain hydrogenated graphenes (also termed graphane if fully hydrogenated), which exhibited properties including fluorescence, magnetism and a tuneable band gap. Although the classical Birch reduction has been employed for hydrogenation of graphite oxide, variation exists between the choice of alkali metals and alcohols/water as quenching agents. A systematic study of electron (Li, Na, K, Cs) and proton sources (tBuOH, iPrOH, MeOH, H2O) has been performed to identify optimal conditions. The proton source exerted a great influence on the resulting hydrogenation with water and out-performed alcohols, and the lowest carbon-to-hydrogen ratio was observed with sodium and water with composition of C1.4H1O0.3. Although ferromagnetism at room temperature correlates well with increasing hydrogen concentrations, small contributions from trace iron impurities cannot be completely eliminated. In contrast, hydrogenated graphenes exhibit a significant paramagnetic moment at low temperatures that has no correlation with impurities, and therefore, originates from the carbon system. This is in comparison to graphene, which is strongly diamagnetic, and concentrations of paramagnetic centres in hydrogenated graphenes are one order of magnitude larger than that in graphite. Nonetheless, hydrogenation over a particular level might also excessively disrupt intrinsic sp(2) conjugation, resulting in unintended reduction of electrochemical properties. This was observed with heterogeneous electron-transfer rates and it was postulated that hydrogenated graphenes should generally have high defect densities, but only moderately high hydrogenation, should they be employed as electrode materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. 1H DNP at 1.4 T of water doped with a triarylmethyl-based radical.

    PubMed

    Wind, R A; Ardenkjaer-Larsen, J H

    1999-12-01

    Recently a triarylmethyl-based (TAM) radical has been developed for research in biological and other aqueous systems, and in low magnetic fields, 10 mT or less, large (1)H dynamic nuclear polarization (DNP) enhancements have been reported. In this paper the DNP properties of this radical have been investigated in a considerably larger field of 1.4 T, corresponding to proton and electron Larmor frequencies of 60 MHz and 40 GHz, respectively. To avoid excessive microwave heating of the sample, an existing DNP NMR probe was modified with a screening coil, wound around the sample capillary and with its axis perpendicular to the electric component of the microwave field. It was found that with this probe the temperature increase in the sample after 4 s of microwave irradiation with an incident power of 10 W was only 16 degrees C. For the investigations, 10 mM of the TAM radical was dissolved in deionized, but not degassed, water and put into a 1-mm i.d. and 6-mm long capillary tube. At 26 degrees C the following results were obtained: (I) The relaxivity of the radical is 0.07 (mMs)(-1), in accordance with the value extrapolated from low-field results; (II) The leakage factor is 0.63, the saturation factor at maximum power is 0.85, and the coupling factor is -0.0187. It is shown that these results agree very well with an analysis where the electron-dipolar interactions are the dominant DNP mechanism, and where the relaxation transitions resulting from these interactions are governed by translational diffusion of the water molecules. Finally, the possibilities of combining DNP with magnetic resonance microscopy (MRM) are discussed. It is shown that at 26 degrees C the overall DNP-enhanced proton polarization should become maximal in an external field of 0.3 T and become comparable to the thermal equilibrium polarization in a field of 30 T, considerably larger than the largest high-resolution magnet available to date. It is concluded that DNP MRM in this field, which

  3. Effect of Triplet Magnet Vibrations on RHIC Performance with High Energy Protons

    SciTech Connect

    Minty, M.

    2010-05-23

    In this report we present recent experimental data from the Relativistic Heavy Ion Collider (RHIC) illustrating effects resulting from {approx}10 Hz vibrations of the triplet quadrupole magnets in the interactions regions and evaluate the impact of these vibrations on RHIC collider performance. Measurements revealed modulation of the betatron tunes of appreciable magnitude relative to the total beam-beam parameter. Comparison of the discrete frequencies in the spectra of the measured beam positions and betatron tunes confirmed a common source. The tune modulations were shown to result from feed-down in the sextupole magnets in the interaction regions. In addition we show that the distortions to the closed orbit of the two counter-rotating beams produced a modulated crossing angle at the interaction point(s).

  4. Abdominal visceral adiposity influences CD4+ T cell cytokine production in pregnancy.

    PubMed

    Ozias, Marlies K; Li, Shengqi; Hull, Holly R; Brooks, William M; Petroff, Margaret G; Carlson, Susan E

    2015-02-01

    Women with pre-gravid obesity are at risk for pregnancy complications. While the macrophage response of obese pregnant women categorized by body mass index (BMI) has been documented, the relationship between the peripheral CD4(+) T cell cytokine profile and body fat compartments during pregnancy is unknown. In this study, third trimester peripheral CD4(+) T cell cytokine profiles were measured in healthy pregnant women [n=35; pre-pregnancy BMI: 18.5-40]. CD4(+) T cells were isolated from peripheral blood mononuclear cells and stimulated to examine their capacity to generate cytokines. Between 1 and 3weeks postpartum, total body fat was determined by dual-energy X-ray absorptiometry and abdominal subcutaneous and visceral fat masses were determined by magnetic resonance imaging. Pearson's correlation was performed to assess relationships between cytokines and fat mass. Results showed that greater abdominal visceral fat mass was associated with a decrease in stimulated CD4(+) T cell cytokine expression. IFN-gamma, TNF-alpha, IL-12p70, IL-10 and IL-17A were inversely related to visceral fat mass. Chemokines CCL3 and IL-8 and growth factors G-CSF and FLT-3L were also inversely correlated. Additionally, total body fat mass was inversely correlated with FGF-2 while abdominal subcutaneous fat mass and BMI were unrelated to any CD4(+) T cell cytokine. In conclusion, lower responsiveness of CD4(+) T cell cytokines associated with abdominal visceral fat mass is a novel finding late in gestation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Proton magnetic resonance characterization of phoratoxins and homologous proteins related to crambin

    SciTech Connect

    Lecomte, J.T.J.; Kaplan, D.; Llinas, M.; Thunberg, E.; Samuelsson, G.

    1987-02-24

    The mistletoe protein toxins, phoratoxins A and B, viscotoxins A3 and B have been investigated by /sup 1/H NMR spectroscopy at 300 and 600 MHz. The five polypeptides define a set of closely related homologues, containing 46 amino acid residues each, in a structure constrained by three cystine bridges. Their methyl and aromatic spectra were analyzed and a number of signals identified and assigned via comparative criteria, two-dimensional chemical-shift correlated spectroscopy, acid-base titration, and proton Overhauser experiments in /sup 1/H/sub 2/O. The spectra indicate a compact globular conformation and a common folding pattern for the toxins. In particular, use was made of well-resolved aliphatic and aromatic resonances in order to compare the mistletoe proteins with the thionins, a set of homologous toxins from gramineae, and with crambin, a closely related polypeptide from a crucifer. The authors observe that while all the investigated proteins have very similar secondary and tertiary structures, they differ widely in their dynamic characteristics as probed by the amide NH /sup 1/H-/sup 2/H exchange kinetics in deuteriated solvents. The temperature dependence of the /sup 1/H NMR spectrum also indicates that the toxins are endowed with a thermally very stable native (ground-state) structure, with little evidence of large amplitude structural breathings up to approx.370 K, although irreversible chemical degradation (denaturation) becomes evident at temperatures greater than or equal to 350 K. It is concluded that the mistletoe toxins afford valuable rigid structures for NMR conformation studies.

  6. Methods of, and apparatus for, proton decoupling in nuclear magnetic resonance spectroscopy

    SciTech Connect

    Vatis, D.; Bottomley, P.A.; Foster, T.H.

    1987-07-21

    This patent describes an apparatus for providing a radio-frequency signal having at least one selected one of (1) first specie decoupling and (2) nuclear Overhauser enhancement effect, upon a second nuclei specie in a sample in a nuclear magnetic resonance (NMR) experiment, comprising: means for providing a radio-frequency (RF) signal at a center frequency substantially equal to the Larmor frequency of a first specie, different from the second nuclear specie, in the sample; means for modulating the amplitude of the RF signal with a time-dependent sinc (..omega../sub O/t) signal waveform; means for adjusting at least one selected one of (1) the amplitude of the modulated radio-frequency signal and (2) the instantaneous center frequency, across a range of frequencies related to a chemical shift spectrum ..omega../sub O/ of the first specie; and means for applying the adjusted signal to the sample to cause at least one selected one of (1) minimization of the coupling of the first nuclear specie to, and (2) nuclear Overhauser enhancement of, magnetic resonance spectroscopy response signals provided by the second nuclear specie.

  7. Nuclear magnetic resonance of external protons using continuous dynamical decoupling with shallow NV centers

    NASA Astrophysics Data System (ADS)

    de Las Casas, Charles; Ohno, Kenichi; Awschalom, David D.

    2015-03-01

    The nitrogen vacancy (NV) center in diamond is a paramagnetic defect with excellent spin properties that can reside within a few nanometers of the diamond surface, enabling atomic-scale magnetic resonance sensing of external nuclear spins. Here we use rotating frame longitudinal spin relaxation (T1ρ) based sensing schemes, known as Continuous Dynamical Decoupling (CDD), to detect external nuclear spins with shallow NV centers (<5 nm from the surface). Distinguishing neighboring nuclear spins from each other requires the NV center be near enough to create differences in the hyperfine shifts and coupling strengths of the nuclei. However, spin coherence time and consequently the sensitivity of dynamical decoupling techniques degrade sharply as NVs become shallower. We use strong continuous driving to overcome this fast decoherence and detect an ensemble of external nuclear spins using a single shallow NV center with a short T2 (<2 μs) at magnetic fields as high as 0.5 Tesla. The increased sensitivity of this method relative to pulsed dynamical decoupling techniques demonstrates the benefits of CDD for sensing with very shallow NV centers. This work was supported by DARPA, AFOSR, and the DIAMANT program.

  8. Dysregulation of CD4(+) T Cell Subsets in Intracranial Aneurysm.

    PubMed

    Zhang, Hai-Feng; Zhao, Ming-Guang; Liang, Guo-Biao; Yu, Chun-Yong; He, Wenxiu; Li, Zhi-Qing; Gao, Xu

    2016-02-01

    Intracranial aneurysms (IAs) and potential IA rupture are one of the direct causes of permanent brain damage and mortality. Interestingly, the major risk factors of IA development, including hemodynamic stress, hypertension, smoking, and genetic predispositions, are closely associated with a proinflammatory immune status. Therefore, we examined the roles of CD4(+) T cells in IA pathogenesis. IA patients exhibited peripheral CD4(+) T-cell imbalance, with overrepresented T helper 1 (Th1) and Th17 activities and underrepresented Th2 and regulatory T (Treg) activities, including increased IFN-γ, TNF-α, and IL-17 production and decreased IL-10 production from total CD4(+) T cells. Chemokine receptors CXCR3 and CCR6 were used to identify Th1, Th2, and Th17 cell subsets, and CD4(+)CD25(hi) was used to identify Treg cells. Based on these markers, the data then showed altered cytokine production by each cell type and shifted subpopulation frequency. Moreover, this shift in frequency was directly correlated with IA severity. To examine the underlying mechanism of CD4(+) T cell skewing, we cocultured CD4(+) T cells with autologous monocytes and found that coculture with monocytes could significantly increase IFN-γ and IL-17 production through contact-independent mechanisms, demonstrating that monocytes could potentially contribute to the altered CD4(+) T cell composition in IA. Analyzing mRNA transcripts revealed significantly upregulated IL-1β and TNF-α expression by monocytes from IA patients. We found a loss of CD4(+) T cell subset balance that was likely to promote a higher state of inflammation in IA, which may exacerbate the disease through a positive feedback loop.

  9. Elevated prefrontal cortex GABA in patients with major depressive disorder after TMS treatment measured with proton magnetic resonance spectroscopy

    PubMed Central

    Dubin, Marc J.; Mao, Xiangling; Banerjee, Samprit; Goodman, Zachary; Lapidus, Kyle A.B.; Kang, Guoxin; Liston, Conor; Shungu, Dikoma C.

    2016-01-01

    Background GABAergic and glutamatergic neurotransmitter systems are central to the pathophysiology of depression and are potential targets of repetitive transcranial magnetic stimulation (rTMS). We assessed the effect of 10-Hz rTMS over the left dorsolateral prefrontal cortex (DLPFC) of patients with major depressive disorder on the levels of medial prefrontal cortex (MPFC) γ-aminobutyric acid (GABA) and the combined resonance of glutamate and glutamine (Glx) as assessed in vivo with proton magnetic resonance spectroscopy (1H MRS). Methods Currently depressed individuals between the ages of 23 and 68 years participated in a 5-week naturalistic, open-label treatment study of rTMS, with 1H MRS measurements of MPFC GABA and Glx levels at baseline and following 5 weeks of the rTMS intervention. We applied rTMS pulses over the left DLPFC at 10 Hz and 80%–120% of motor threshold for 25 daily sessions, with each session consisting of 3000 pulses. We assessed therapeutic response using the 24-item Hamilton Rating Scale for Depression (HAMD24). The GABA and Glx levels are expressed as ratios of peak areas relative to the area of the synchronously acquired and similarly fitted unsuppressed voxel water signal (W). Results Twenty-three currently depressed individuals (7 men) participated in the study. GABA/W in the MPFC increased 13.8% (p = 0.013) in all depressed individuals. There were no significant effects of rTMS on Glx/W. GABA/W and Glx/W were highly correlated in severely depressed patients at baseline but not after TMS. Limitations The primary study limitations are the open-label design and the inclusion of participants currently taking stable regimens of antidepressant medications. Conclusion These results implicate GABAergic and glutamatergic systems in the mechanism of action of rTMS for major depression, warranting further investigation in larger samples. PMID:26900793

  10. Methamphetamine users in sustained abstinence: a proton magnetic resonance spectroscopy study.

    PubMed

    Nordahl, Thomas E; Salo, Ruth; Natsuaki, Yutaka; Galloway, Gantt P; Waters, Christy; Moore, Charles D; Kile, Shawn; Buonocore, Michael H

    2005-04-01

    Abnormal patterns of metabolite levels have been detected by magnetic resonance spectroscopy in frontostriatal regions of individuals meeting DSM-IV criteria for methamphetamine dependence, but less is known about the effects of drug abstinence on metabolite levels. To assess the effects of long-term methamphetamine use and drug abstinence on brain metabolite levels. To assess regional specific metabolite levels using magnetic resonance spectroscopy imaging techniques in 2 groups of currently abstinent methamphetamine users: methamphetamine users who recently initiated abstinence and methamphetamine users who had initiated abstinence more than 1 year prior to study. Participants were recruited from outpatient substance abuse treatment centers. Eight methamphetamine users with sustained abstinence (1 year to 5 years) and 16 recently abstinent methamphetamine users (1 month to 6 months) were compared with 13 healthy, non-substance-using controls. Magnetic resonance spectroscopy measures of N-acetylaspartate-creatine and phosphocreatine (NAA/Cr), choline-creatine and phosphocreatine (Cho/Cr), and choline-N-acetylaspartate (Cho/NAA) ratios were obtained in the anterior cingulate cortex as well as in the primary visual cortex, which served as a control region. The absolute values of Cr did not differ between controls and methamphetamine users. Methamphetamine users had abnormally low NAA/Cr levels within the anterior cingulate cortex, regardless of the time spent abstinent (F(2,34) = 12.61; P<.001). No NAA/Cr group differences were observed in the primary visual cortex (F(2,33) = 0.29; P = .75). The Cho/NAA values for the anterior cingulate cortex were abnormally high in the methamphetamine users who recently initiated abstinence but followed a normal pattern in the methamphetamine users who had initiated abstinence more than 1 year prior to study (F(2,34) = 7.31; P = .002). The relative choline normalization across periods of abstinence suggests that following

  11. Evaluating Human Breast Ductal Carcinomas with High-Resolution Magic-Angle Spinning Proton Magnetic Resonance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Cheng, Leo Ling; Chang, I.-Wen; Smith, Barbara L.; Gonzalez, R. Gilberto

    1998-11-01

    We report the results of a study of human breast ductal carcinomas, conducted by using high resolution magic angle spinning proton magnetic resonance spectroscopy (HRMAS 1HMRS). This recently developed spectroscopic technique can measure tissue metabolism from intact pathological specimens and identify tissue biochemical changes, which closely correspond to tumorin vivostate. This procedure objectively indicates diagnostic parameters, independent of the skill and experience of the investigator, and has the potential to reduce the sampling errors inherently associated with procedures of conventional histopathology. In this study, we measured 19 cases of female ductal carcinomas. Our results demonstrate that: (1) highly resolved spectra of intact specimens of human breast ductal carcinomas can be obtained; (2) carcinoma-free tissues and carcinomas are distinguishable by alterations in the intensities and the spin-spin relaxation time T2 of cellular metabolites; and (3) tumor metabolic markers, such as phosphocholine, lactate, and lipids, may correlate with the histopathological grade determined from evaluation of the adjacent specimen. Our results suggest that biochemical markers thus measured may function as a valuable adjunct to histopathology to improve the accuracy of and reduce the time frame required for the diagnosis of human breast cancer.

  12. [Effects of dioscorea modified pill on cognitive impairment of patients with VCIND: an preliminary study of proton magnetic resonance spectroscopy].

    PubMed

    Liu, Jinhuan; Chen, Jun; Tan, Zihu; Yang, Qiong; Lan, Hanchao; Zhao, Yilin; Liu, Changsheng; Qiu, Li

    2014-10-28

    To explore the therapeutic effect evaluation of proton magnetic resonance spectroscopy ((1)H-MRS) in patients with vascular cognitive impairment no dementia (VCIND) with dioscorea modified pill. A total of 100 patients with VCIND were randomly assigned into the dioscorea modified pill group (n = 50) and the aricept group (n = 50). And 50 healthy volunteers were recruited as normal group. Each patient was examined with (1)H-MRS and scored with mini-mental state examination (MMSE) and clinical dementia rating (CDR) scale pre- and post-treatment. After therapy, the NAA/Cr ratios and the itemized scores of cognitive scale compared with that of pre-therapy had significantly difference (P < 0.05) in the dioscorea modified pill group (MMSE (26.5 ± 2.0), CDR(0.14 ± 0.23))vs(MMSE(25.1 ± 2.3), CDR(0.5)). But no difference existed in the aricept group (P > 0.05). (1)H-MRS may objectively reflect cognitive dysfunction in VCIND patients. And it has important values in the therapeutic effect evaluation of VCIND with dioscorea modified pill.

  13. The prognostic value of proton magnetic resonance spectroscopy in term newborns treated with therapeutic hypothermia following asphyxia.

    PubMed

    Sijens, Paul E; Wischniowsky, Katharina; Ter Horst, Hendrik J

    2017-10-01

    The purpose of this study was to correlate brain metabolism assessed shortly after therapeutic hyperthermia by (1)H magnetic resonance spectroscopy (MRS), with neurodevelopmental outcome. At the age of 6.0±1.8days, brain metabolites of 35 term asphyxiated newborns, treated with therapeutic hypothermia, were quantified by multivoxel proton MRS of a volume cranial to the corpus callosum, containing both gray and white matter. At the age of 30months the Bayley Scale of Infant Development-III was performed. Infants that died had lower gray matter NAA levels than infants that survived (P=0.005). In surviving infants (28 of 35) there was a trend of negative correlation between gray matter choline levels and gross motor outcome (r=-0.45). In the white matter, choline correlated negatively with fine motor skills (r=-0.40), and creatine positively with gross motor skills (r=0.58, P=0.02). There was no relationship between lactate levels and outcome. MRS of asphyxiated neonates treated by therapeutic hypothermia can serve as predictor of outcome. Unlike previously reported associations in untreated asphyxiates, lactate levels had no relationship with outcome, which indicates that one of the working mechanisms of therapeutic hypothermia is reduction of the metabolic rate. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Brain metabolite changes in patients with type 2 diabetes and cerebral infarction using proton magnetic resonance spectroscopy.

    PubMed

    Zhang, Min; Sun, Xinhai; Zhang, Zhengjun; Meng, Qiang; Wang, Yuzhong; Chen, Jing; Ma, Xueqin; Geng, Houfa; Sun, Lin

    2014-01-01

    The aim of this study was to investigate the possible brain metabolic alterations in patients with type 2 diabetes mellitus (T2DM) and cerebral infarction (DMCI) using proton magnetic resonance spectroscopy (MRS). Thirty-four patients with T2DM and DMCI were scanned together with 33 patients with nondiabetic cerebral infarction (NDCI) on a 1.5-T MRI/MRS imager. Voxels were placed in the infarcted area and the contralateral normal area in the basal ganglia. N-acetylaspartate (NAA)/creatine (Cr), choline (Cho)/Cr, and lactate (Lac)/Cr ratios were calculated. Cerebral NAA/Cr ratios in the infarcted area were lower than those in the contralateral normal area of the NDCI group. There was a significant decrease in NAA/Cr in the infarcted area of the DMCI group as compared with the infarcted area of the NDCI group. NAA/Cr ratios in the contralateral normal area of DMCI group were lower than those of the NDCI group. Lac/Cr ratios were increased in the infarcted area of both the DMCI group and NDCI group, and Lac/Cr ratios tended to be higher in the infarcted area of the DMCI group than those of the NDCI group. Glycosylated hemoglobin (HbA1c) levels were negatively correlated with NAA/Cr ratios. The study suggested that the metabolite changes were different between DMCI patients and NDCI patients, which may provide important information in the treatment of DMCI.

  15. Evaluation of neuron-glia integrity by in vivo proton magnetic resonance spectroscopy: Implications for psychiatric disorders.

    PubMed

    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.

  16. A case-control proton magnetic resonance spectroscopy study confirms cerebellar dysfunction in benign adult familial myoclonic epilepsy

    PubMed Central

    Long, Lili; Song, Yanmin; Zhang, Linlin; Hu, Chongyu; Gong, Jian; Xu, Lin; Long, Hongyu; Zhou, Luo; Zhang, Yunci; Zhang, Yong; Xiao, Bo

    2015-01-01

    Background Benign adult familial myoclonic epilepsy (BAFME) is a rare form of epilepsy syndrome. The pathogenesis of BAFME remains unclear, though it seems to involve dysfunction of the cerebellum. Objectives The purpose of this study was to use proton magnetic resonance spectroscopy (1H-MRS) to investigate whether neurochemical changes underlie abnormal brain function in BAFME. Methods Twelve BAFME patients from one family and 12 age- and sex-matched healthy controls were enrolled in this study. The ratios of NAA/Cr, NAA/Cho, Cho/Cr, and NAA/(Cr+Cho) were analyzed. Results The BAFME patients exhibited a decreased N-acetylaspartate (NAA)/choline (Cho) ratio in the cerebellar cortex, whereas there were no significant differences in the NAA/creatine (Cr), Cho/Cr, and NAA/(Cr+Cho) ratios compared with healthy controls. There were no significant differences in 1H-MRS values in the frontal cortex or thalamus between the BAFME patients and controls. No correlation was detected between the NAA/Cho ratio in the cerebellar cortex and disease duration, myoclonus severity, or tremor severity. Conclusion Our results indicate clear cerebellar dysfunction in BAFME. 1H-MRS is a useful tool for the diagnosis of BAFME in combination with family history and electrophysiological examination. PMID:25750529

  17. Application of proton magnetic resonance spectroscopy and computerized tomography in the diagnosis and treatment of nonalcoholic fatty liver disease.

    PubMed

    Wang, Nan; Dong, Hui; Wei, Shichao; Lu, Fuer

    2008-06-01

    In order to investigate the application of proton magnetic resonance spectroscopy ((1)H-MRS) and computerized tomography (CT) in the quantitative diagnosis of nonalcoholic fatty liver disease (NAFLD) and evaluation of therapeutic effects, 22 patients with NAFLD were selected according to the Chinese Medical Association's (CMA) standard of the NAFLD in comparison with 20 healthy volunteers (as control group). Blood samples for biochemistry were collected. The severity of hepatosteatosis was evaluated by (1)H-MRS scan and CT scan of liver. The intrahepatic content of lipid (IHCL) and CT value ratio of liver to spleen were calculated. The patients in NAFLD group were treated with Ganzhixiao Capsule for 8 weeks. The changes in IHCL and CT value ratio of liver to spleen were observed before and after treatment. In NAFLD group serum ALT, TG, IHCL calculated by (1)HMRS were increased and CT value ratio of liver to spleen decreased significantly as compared with control group. After treatment for 8 weeks serum ALT, TG, IHCL were decreased significantly, while CT value ratio of liver to spleen increased significantly in NAFLD group. It was suggested that IHCL could be measured precisely by (1)HMRS. NAFLD was treated effectively by Ganzhixiao capsule.

  18. Alterations of GABA and glutamate-glutamine levels in premenstrual dysphoric disorder: a 3T proton magnetic resonance spectroscopy study.

    PubMed

    Liu, Bo; Wang, Guangbin; Gao, Dongmei; Gao, Fei; Zhao, Bin; Qiao, Mingqi; Yang, Huan; Yu, Yanhong; Ren, Fuxin; Yang, Ping; Chen, Weibo; Rae, Caroline D

    2015-01-30

    Increasing evidence has suggested that the GABAergic neurotransmitter system is involved in the pathogenesis of premenstrual dysphoric disorder (PMDD). We used proton magnetic resonance spectroscopy ((1)H MRS) to investigate whether PMDD is associated with alterations in brain GABA levels. Levels of glutamate-glutamine (Glx) were also explored. Participants comprised 22 women with PMDD and 22 age-matched healthy controls who underwent 3T (1)H MRS during the late luteal phase of the menstrual cycle. GABA+ and Glx levels were quantified in the anterior cingulate cortex/medial prefrontal cortex (ACC/mPFC) and the left basal ganglia (ltBG). Water-scaled GABA+ concentrations and GABA+/tCr ratios were significantly lower in both the ACC/mPFC and ltBG regions of PMDD women than in healthy controls. Glx/tCr ratios were significantly higher in the ACC/mPFC region of PMDD women than healthy controls. Our preliminary findings provide the first report of abnormal levels of GABA+ and Glx in mood-related brain regions of women with PMDD, indicating that dysregulation of the amino acid neurotransmitter system may be an important neurobiological mechanism in the pathogenesis of PMDD.

  19. Three dimensional structure prediction and proton nuclear magnetic resonance analysis of toxic pesticides in human blood plasma.

    PubMed

    Sharma, Amit Kumar; Tiwari, Rajeev Kumar; Gaur, Mulayam Singh

    2012-05-01

    The purpose of this study was to investigate the nuclear magnetic resonance (NMR) assignments of hydrolyzed products extracted from human blood plasma. The correlations between chemical, functional and structural properties of highly toxic pesticides were investigated using the PreADME analysis. We observed that toxic pesticides possessed higher molecular weight and, more hydrogen bond donors and acceptors when compared with less toxic pesticides. The occurrence of functional groups and structural properties was analyzed using (1)H-NMR. The (1)H-NMR spectra of the phosphomethoxy class of pesticides were characterized by methyl resonances at 3.7-3.9 ppm (δ) with the coupling constants of 11-16 Hz (JP-CH3 ). In phosphoethoxy pesticides, the methyl resonance was about 1.4 ppm (δ) with the coupling constant of 10 Hz (JP-CH2 ) and the methylene resonances was 4.2-4.4 ppm (δ) with the coupling constant of 0.8 Hz (JP-CH3 ), respectively. Our study shows that the values of four parameters such as chemical shift, coupling constant, integration and relaxation time correlated with the concentration of toxic pesticides, and can be used to characterise the proton groups in the molecular structures of toxic pesticides.

  20. Proton Magnetic Resonance Spectroscopy Study on the Metabolism Changes of Cerebellum in Patients with Post-Stroke Depression.

    PubMed

    Zhang, Lei; Sui, Ru-Bo

    2017-01-01

    To study the metabolic changes of cerebellum by proton magnetic resonance Spectroscopy (1H-MRS) and discuss the relationships between the cerebellar changes and depression severity in patients with post-stroke depression. Data of demographic characteristics, individual history and life style of all subjects were collected. 40 patients with stroke and 20 controls were enrolled. All groups received T1WI, T2WI, DWI and 1H-MRS examination. The cerebral infarction volume and the distribution and severity of leukoaraiosis were evaluated. The ratios of NAA/Cr, Cho/Cr and Cho/NAA in the cerebellum were calculated. There were no statistical significant difference in the NAA/Cr, Cho/Cr and Cho/NAA ratios in bilateral cerebellum between CONT group and NORM group. The Cho/Cr and Cho/NAA ratios in the cerebellum contralateral to the stroke region were higher in PSD group than those in NORM and CONT groups, and the Cho/Cr and Cho/NAA ratios in the cerebellum ipsilateral to the stroke region were similar with those in NORM and CONT groups. However, there were no statistical significant difference in the NAA/Cr ratios in bilateral cerebellum among three groups. The result shows preliminarily that the cerebellum involves in the development of post-stroke depression. © 2017 The Author(s). Published by S. Karger AG, Basel.

  1. Choline-containing compounds detected by proton magnetic resonance spectroscopy in the basal ganglia in bipolar disorder.

    PubMed Central

    Kato, T; Hamakawa, H; Shioiri, T; Murashita, J; Takahashi, Y; Takahashi, S; Inubushi, T

    1996-01-01

    Choline-containing compounds (Cho) were examined by proton magnetic resonance spectroscopy (1H-MRS) in the left subcortical region, including basal ganglia, in 19 euthymic patients with bipolar disorder and 19 age-matched normal controls. Ten of the patients were treated with lithium; the remaining 9 were not treated with lithium for at least 30 d. The Cho to creatine + phosphocreatine (Cr) peak ratio in the bipolar patients (0.75 +/- 0.38 [mean +/- SD]) was higher than that in the normal controls (0.52 +/- 0.26, P < 0.05). There was no significant difference in the Cho:Cr peak ratio between patients treated with lithium (0.63 +/- 0.36) and without lithium (0.89 +/- 0.35). These results do not support the hypothesis that lithium increases the brain choline-containing compounds, but rather imply that membrane breakdown may occur in the basal ganglia of patients with bipolar disorder. Images Figure 1 PMID:8754593

  2. Evaluation of the keyhole technique applied to the proton resonance frequency method for magnetic resonance temperature imaging.

    PubMed

    Han, YongHee; Mun, ChiWoong

    2011-11-01

    To evaluate the temporal and spatial resolution of magnetic resonance (MR) temperature imaging when using the proton resonance frequency (PRF) method combined with the keyhole technique. Tissue-mimicking phantom and swine muscle tissue were microwave-heated by a coaxial slot antenna. For the sake of MR hardware safety, MR images were sequentially acquired after heating the subjects using a spoiled gradient (SPGR) pulse sequence. Reference raw (k-space) data were collected before heating the subjects. Keyhole temperature images were reconstructed from full k-space data synthesized by combining the peripheral phase-encoding part of the reference raw data and the center phase-encoding keyhole part of the time sequential raw data. Each keyhole image was analyzed with thermal error, and the signal-to-noise ratio (SNR) was compared with the self-reference (nonkeyhole) images according to the number of keyhole phase-encoding (keyhole-data size) portions. In applied keyhole temperature images, smaller keyhole-data sizes led to more temperature error increases, but the SNR did not decreased comparably. Additionally, keyhole images with a keyhole-data size of <16 had significantly different temperatures compared with fully phase-encoded self-reference images (P < 0.05). The keyhole technique combined with the PRF method improves temporal resolution and SNR in the measurement of the temperature in the deeper parts of body in real time. Copyright © 2011 Wiley Periodicals, Inc.

  3. Amide proton transfer magnetic resonance imaging in detecting intracranial hemorrhage at different stages: a comparative study with susceptibility weighted imaging

    PubMed Central

    Ma, Xiaoyue; Bai, Yan; Lin, Yusong; Hong, Xiaohua; Liu, Taiyuan; Ma, Lun; Haacke, E Mark; Zhou, Jinyuan; Wang, Jian; Wang, Meiyun

    2017-01-01

    Amide proton transfer (APT) imaging is a noninvasive molecular magnetic resonance imaging (MRI) technique based on the chemical exchange-dependent saturation transfer mechanism. The purpose of this study was to investigate the diagnostic performance of APT MRI in detecting intracranial hemorrhage (ICH) at hyperacute, acute and subacute stages by comparing with susceptibility weighted imaging (SWI). APT MRI and SWI were performed on 33 included patients with ICH by using a 3-T MRI unit. A two-sided Mann-Whitney U test was used to detect differences in APT-weighted (APTw) and SWI signal intensities of ICH at hyperacute, acute and subacute stages. Receiver operating characteristic analysis was used to assess the diagnostic utilities of APT MRI and SWI. Our results showed that APT MRI could detect ICH at hyperacute, acute and subacute stages. Therefore, APTw signal intensity may serve as a reliable, noninvasive imaging biomarker for detecting ICH at hyperacute, acute and subacute stages. Moreover, APT MRI could provide additional information for the ICH compared with SWI. PMID:28374764

  4. Proton-conductive magnetic metal-organic frameworks, {NR3(CH2COOH)}[M(a)(II)M(b)(III)(ox)3]: effect of carboxyl residue upon proton conduction.

    PubMed

    Ōkawa, Hisashi; Sadakiyo, Masaaki; Yamada, Teppei; Maesato, Mitsuhiko; Ohba, Masaaki; Kitagawa, Hiroshi

    2013-02-13

    Proton-conductive magnetic metal-organic frameworks (MOFs), {NR(3)(CH(2)COOH)}[M(a)(II)M(b)(III)(ox)(3)] (abbreviated as R-M(a)M(b): R = ethyl (Et), n-butyl (Bu); M(a)M(b) = MnCr, FeCr, FeFe) have been studied. The following six MOFs were prepared: Et-MnCr·2H(2)O, Et-FeCr·2H(2)O, Et-FeFe·2H(2)O, Bu-MnCr, Bu-FeCr, and Bu-FeFe. The structure of Bu-MnCr was determined by X-ray crystallography. Crystal data: trigonal, R3c (#161), a = 9.3928(13) Å, c = 51.0080(13) Å, Z = 6. The crystal consists of oxalate-bridged bimetallic layers interleaved by {NBu(3)(CH(2)COOH)}(+) ions. Et-MnCr·2H(2)O and Bu-MnCr (R-MnCr MOFs) show a ferromagnetic ordering with T(C) of 5.5-5.9 K, and Et-FeCr·2H(2)O and Bu-FeCr (R-FeCr MOFs) also show a ferromagnetic ordering with T(C) of 11.0-11.5 K. Et-FeFe·2H(2)O and Bu-FeFe (R-FeFe MOFs) belong to the class II of mixed-valence compounds and show the magnetism characteristic of Néel N-type ferrimagnets. The Et-MOFs (Et-MnCr·2H(2)O, Et-FeCr·2H(2)O and Et-FeFe·2H(2)O) show high proton conduction, whereas the Bu-MOFs (Bu-MnCr, Bu-FeCr, and Bu-FeFe) show moderate proton conduction. Together with water adsorption isotherm studies, the significance of the carboxyl residues as proton carriers is revealed. The R-MnCr MOFs and the R-FeCr MOFs are rare examples of coexistent ferromagnetism and proton conduction, and the R-FeFe MOFs are the first examples of coexistent Néel N-type ferrimagnetism and proton conduction.

  5. Quantitative proton nuclear magnetic resonance for the structural and quantitative analysis of atropine sulfate.

    PubMed

    Shen, Shi; Yao, Jing; Shi, Yaqin

    2014-02-01

    This study assessed a general method of quantitative nuclear magnetic resonance (qNMR) for the calibration of atropine sulfate (Active Pharmaceutical Ingredient, API) as reference standard. The spectra were acquired in D2O using maleic acid as the internal standard. Conformational behaviors of tropane ring were observed and studied by means of NMR and ROESY experiments at different temperature, which showed that the azine methyl group was at equilibrium for axial and equatorial conformations at room temperature. Signal delay and monitor signals of qNMR experimentation were optimized for quantification. The study reported here validated the method's linearity, range, limit of quantification, stability and precision. The results were consistent with the results obtained from mass balance approach.

  6. Proton magnetic resonance neurospectroscopy and EEG cartography in corticobasal degeneration: correlations with neuropsychological signs

    PubMed Central

    Vion-Dury, J; Rochefort, N; Michotey, P; Planche, D; Ceccaldi, M

    2004-01-01

    Methods: Eight patients with probable CBD were included in the study after full neurological examination and extensive neuropsychological testing, single photon emission computed tomography, anatomical x ray tomodensitometry (TDM), magnetic resonance imaging, and MRS examination. Results: MR spectra were abnormal in all seven patients in whom the examination could be completed. The EEG was also always modified in the CBD patients, and the abnormalities were enhanced by activation procedures. There was a good correlation between MRS anomalies and clinical presentation, between EEG modifications and neuropsychological patterns, and between metabolic (MRS) impairment and electrophysiological (EEG) slowing. Conclusions: These results confirm the asymmetrical features of CBD. Combined EEGq/MRS examinations at disease onset and during its subsequent course could provide strong diagnostic evidence of CBD. PMID:15314134

  7. Comparisons of Simulated and Observed Stormtime Magnetic Intensities, Ion Plasma Parameters, and ENA Proton Flux in the Ring Current During Storms

    NASA Astrophysics Data System (ADS)

    Chen, M. W.; Lemon, C.; Guild, T. B.; Schulz, M.; Roeder, J. L.; Le, G.; Lui, T.; Goldstein, J.

    2010-12-01

    In this study we compare simulated and observed stormtime magnetic intensities, proton flux spectra and/or ENA fluxes for two storm events to test how well self-consistent simulations can simultaneously reproduce these quantities. We simulate the ring current and plasma sheet using the magnetically and electrostatically self-consistent Rice Convection Model-Equilibrium (RCM-E) [Lemon et al., JGR, 2004] with a time-varying magnetopause driven by upstream solar wind and interplanetary magnetic field (IMF) conditions. Using either in-situ data (e.g., LANL/MPA and SOPA) or the empirical IMF-dependent model of Tsyganenko and Mukai [JGR, 2003], we specify the plasma sheet pressure and density at 10 Earth radii as the plasma boundary location in the RCM-E. We compare the simulated magnetic intensity with the magnetic intensity measured by magnetometers on the GOES satellites at geosynchronous altitude (6.6 Earth radii) and any other available satellite. We simulate a larger (11 August 2000; minimum Dst = -106 nT) and a smaller (6 April 2010; minimum Dst = 73 nT) storm. For the 11 August 2000 storm, we compare simulated and observed proton spectra (LANL/MPA and SOPA and Polar/CAMMICE). For the more recent 6 April 2010 storm we compare simulated and observed proton spectra (THEMIS) and energetic neutral atom (ENA) flux (TWINS). We discuss the response of the ring current magnetic field and ion flux distribution to expansions and compressions of the magnetosphere associated with the dynamic solar wind pressure for these storm events.

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

    PubMed Central

    Stehouwer, Bertine L.; Boer, Vincent O.; Luijten, Peter R.; Klomp, Dennis W.J.; Wijnen, Jannie P.

    2016-01-01

    In vivo water‐ and fat‐suppressed 1H magnetic resonance spectroscopy (MRS) and 31P 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 31P metabolites were determined, and the reproducibility of 1H and 31P MRS was investigated. The transverse relaxation times for phosphoethanolamine (PE) and phosphocholine (PC) were fitted bi‐exponentially, with an added short T 2 component of 20 ms for adenosine monophosphate, resulting in values of 199 ± 8 and 239 ± 14 ms, respectively. The transverse relaxation time for glycerophosphocholine (GPC) was also fitted bi‐exponentially, with an added short T 2 component of 20 ms for glycerophosphatidylethanolamine, which resonates at a similar frequency, resulting in a value of 177 ± 6 ms. Transverse relaxation times for inorganic phosphate, γ‐ATP and glycerophosphatidylcholine mobile phospholipid were fitted mono‐exponentially, resulting in values of 180 ± 4, 19 ± 3 and 20 ± 4 ms, respectively. Coefficients of variation for the duplicate determinations of 1H total choline (tChol) and the 31P metabolites were calculated for the group of volunteers. The reproducibility of inorganic phosphate, the sum of phosphomonoesters and the sum of phosphodiesters with 31P MRS imaging was superior to the reproducibility of 1H MRS for tChol. 1H and 31P data were combined to calculate estimates of the absolute concentrations of PC, GPC and PE in healthy fibroglandular tissue, resulting in upper limits of 0.1, 0.1 and 0.2 mmol/kg of tissue, respectively. PMID:28032377

  9. Normalization of CD4+ T Cell Metabolism Reverses Lupus

    PubMed Central

    Yin, Yiming; Choi, Seung-Chul; Xu, Zhiwei; Perry, Daniel J.; Seay, Howard; Croker, Byron P.; Sobel, Eric S.; Brusko, Todd M.; Morel, Laurence

    2015-01-01

    Systemic Lupus Erythematosus (SLE) is an autoimmune disease in which autoreactive CD4+ T cells play an essential role. CD4+ T cells rely on glycolysis for inflammatory effector functions, but recent studies have shown that mitochondrial metabolism supports their chronic activation. How these processes contribute to lupus is unclear. Here, we show that both glycolysis and mitochondrial oxidative metabolism are elevated in CD4+ T cells from lupus-prone B6.Sle1.Sle2.Sle3 (TC) mice as compared to non-autoimmune controls. In vitro, both the mitochondrial metabolism inhibitor metformin and the glucose metabolism inhibitor 2-Deoxy-D-glucose (2DG) reduced IFNγ production, although at different stages of activation. Metformin also restored the defective IL-2 production by TC CD4+ T cells. In vivo, treatment of TC mice and other lupus models with a combination of metformin and 2DG normalized T cell metabolism and reversed disease biomarkers. Further, CD4+ T cells from SLE patients also exhibited enhanced glycolysis and mitochondrial metabolism that correlated with their activation status, and their excessive IFNγ production was significantly reduced by metformin in vitro. These results suggest that normalization of T cell metabolism through the dual inhibition of glycolysis and mitochondrial metabolism is a promising therapeutic venue for SLE. PMID:25673763

  10. Proton magnetic resonance spectroscopy of human brain in vivo in the evaluation of multiple sclerosis: Assessment of the load of disease

    SciTech Connect

    Arnold, D.L.; Matthews, P.M.; Francis, G.; Antel, J. )

    1990-04-01

    Image localized, water-suppressed proton magnetic resonance spectra were obtained from affected brain in patients with multiple sclerosis. In patients with moderate to severe chronic disease, spectra revealed a decreased ratio of N-acetylaspartate to creatine resonance intensities. A normal ratio was obtained from a large recently symptomatic MRI plaque that resolved without sequelae. We propose that the observed metabolite changes can be useful as an index of irreversible CNS injury.

  11. Transcriptional Regulatory Networks for CD4 T Cell Differentiation

    PubMed Central

    Zhu, Jinfang

    2015-01-01

    CD4+ T cells play a central role in controlling the adaptive immune response by secreting cytokines to activate target cells. Naïve CD4+ T cells differentiate into at least four subsets, Th1, Th2, Th17, and inducible regulatory T cells, each with unique functions for pathogen elimination. The differentiation of these subsets is induced in response to cytokine stimulation, which is translated into Stat activation, followed by induction of master regulator transcription factors. In addition to these factors, multiple other transcription factors, both subset specific and shared, are also involved in promoting subset differentiation. This review will focus on the network of transcription factors that control CD4+ T cell differentiation. PMID:24839135

  12. CD4 T cells: fates, functions, and faults

    PubMed Central

    2008-01-01

    In 1986, Mosmann and Coffman identified 2 subsets of activated CD4 T cells, Th1 and Th2 cells, which differed from each other in their pattern of cytokine production and their functions. Our understanding of the importance of the distinct differentiated forms of CD4 T cells and of the mechanisms through which they achieve their differentiated state has greatly expanded over the past 2 decades. Today at least 4 distinct CD4 T-cell subsets have been shown to exist, Th1, Th2, Th17, and iTreg cells. Here we summarize much of what is known about the 4 subsets, including the history of their discovery, their unique cytokine products and related functions, their distinctive expression of cell surface receptors and their characteristic transcription factors, the regulation of their fate determination, and the consequences of their abnormal activation. PMID:18725574

  13. Characterization of proton exchange membrane materials for fuel cells by solid state nuclear magnetic resonance

    SciTech Connect

    Kong, Zueqian

    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.

  14. Investigating the Dissolution Performance of Amorphous Solid Dispersions Using Magnetic Resonance Imaging and Proton NMR.

    PubMed

    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.

  15. Diet treatment of branched chain ketoaciduria studied by proton magnetic resonance spectroscopy.

    PubMed

    Pontoni, G; Rotondo, F; Vacchiano, T M; Pinto, L; Perrotta, V; Pietra, D D; Cartenì-Farina, M; Zappia, V

    1996-03-01

    A novel nuclear magnetic resonance method is proposed for the diagnosis and follow-up of patients affected by branched chain ketoaciduria. The method allows quantitation of the branched chain amino acids (BCAA's) such as leucine, isoleucine and valine and of related keto- and hydroxy acids by means of a single spectrum. The method implies short time of analysis, as opposed to the very long time required by the techniques currently in use (amino acid analyzer combined with gaschromatography/mass spectrometry of keto- and hydroxyacids), it is easy and suitable for adjustements of the dietary treatment even on a daily basis. The case of a 15 days old newborn child, presenting muscular hypertonicity was unambiguously diagnosed in few minutes by means of one single NMR spectrum of urine. More interestingly, NMR spectra of serum in the following days were suitable for quantitating amino-, and keto acids as well as other metabolites of relevance in the follow up of the dietary treatment of the disease. After a diet lacking of BCAA's, to eliminate keto acids, a low BCAA diet was introduced, that succeeded in keeping the serum levels of the three amino acids within the normal range, while dropping the related keto acids.

  16. New magnetic monopole flux limits from the IMB proton decay detector

    SciTech Connect

    Becker-Szendy, R.; Bratton, C.B.; Breault, J.; Casper, D.; Dye, S.T.; Ganezer, K.; Gajewski, W.; Goldhaber, M.; Haines, T.J.; Halverson, P.G.; Kielczewska, D.; Kropp, W.R.; Learned, J.G.; LoSecco, J.; Matsuno, S.; McGrath, G.; McGrew, C.; Miller, R.S.; Price, L.; Reines, F.; Schultz, J.; Sobel, H.W.; Stone, J.L.; Sulak, L.R.; Svoboda, R. |||||||||

    1994-03-01

    An improved limit on the flux of magnetic monopoles in the vicinity of the solar system is obtained, assuming that monopoles strongly catalyze nucleon decay (the Rubakov-Callan effect). Flux limits are presented for monopole velocities from 10{sup {minus}5}{ital c} to 10{sup {minus}1}{ital c} and for monopole-nucleon cross sections between 10{sup {minus}27} cm{sup 2} and 10{sup {minus}21} cm{sup 2}. For a representative velocity {beta}{approx}10{sup {minus}3}, and cross section {sigma}{approx}10{sup {minus}24} cm{sup 2}, we obtain a limit {ital F}{sub {ital m}}{lt}2.7{times}10{sup {minus}15} cm{sup {minus}2} sr{minus}1 sec {sup {minus}1} and for {sigma}{approx}10{sup {minus}25} cm{sup 2}, {ital F}{sub {ital m}}{lt}1.0{times}10{sup {minus}15} cm{sup {minus}2}sr{sup {minus}1}sec{sup {minus}1} at 90% C.L.

  17. Proton magnetic resonance spectroscopy and outcome in term neonates with chorioamnionitis

    PubMed Central

    Johnson, C B; Jenkins, D D; Bentzley, J P; Lambert, D; Hope, K; Rollins, L G; Morgan, P S; Brown, T; Ramakrishnan, V; Mulvihill, D M; Katikaneni, L D

    2015-01-01

    Objective: Evaluate brain metabolites, which reflect neuroinflammation, and relate to neurodevelopmental outcomes in healthy term neonates exposed to chorioamnionitis. Study Design: Thirty-one healthy term neonates with documented fetal inflammatory response after maternal chorioamnionitis underwent magnetic resonance spectroscopy (MRS), with voxels placed in basal ganglia (BG) and frontal white matter. Bayley III examinations were performed at 12 months of age. Result: Infants with below average outcomes did not show the same increase in NAA/Cho ratios postnatally as the group with normal outcomes. Decreased NAA/Cho and increased Lac/Cr in BG correlated with lower motor and cognitive composite scores, respectively, controlling for postnatal age. In males, increased lactate/NAA in BG were associated with lower motor scores. Funisitis severity was associated with decreased NAA/Cho and increased mI/NAA in males. Conclusion: In healthy term newborns with chorioamnionitis, MRS ratios shortly after birth may provide evidence of occult neuroinflammation, which may be associated with worse performance on 1-year neurodevelopmental tests. PMID:26426253

  18. Proton: the particle.

    PubMed

    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.

  19. Proton: The Particle

    SciTech Connect

    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{sup 80}. Protons were created at 10{sup −6} –1 second after the Big Bang at ≈1.37 × 10{sup 10} years beforethe present. Proton life span has been experimentally determined to be ≥10{sup 34} years; that is, the age of the universe is 10{sup −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{sup +}, W{sup −}, Z{sup 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.

  20. Proton Magnetic Resonance Imaging for Initial Assessment of Isolated Mycobacterium avium Complex Pneumonia.

    PubMed

    Chung, Jonathan H; Huitt, Gwen; Yagihashi, Kunihiro; Hobbs, Stephen B; Faino, Anna V; Bolster, Bradley D; Biederer, Jürgen; Puderbach, Michael; Lynch, David A

    2016-01-01

    Computed tomographic (CT) radiography is the reference standard for imaging Mycobacterium avium complex (MAC) lung infection. Magnetic resonance imaging (MRI) has been shown to be comparable to CT for characterizing other pulmonary inflammatory conditions, but has not been rigorously tested for imaging MAC pneumonia. To determine the feasibility of pulmonary MRI for imaging MAC pneumonia and to assess the degree of agreement between MRI and CT for assessing the anatomic features and lobar extent of MAC lung infections. Twenty-five subjects with culture-confirmed MAC pneumonia and no identified coinfecting organisms were evaluated by thoracic MRI and then by chest CT imaging performed up to 1 week later. After deidentification, first the MRI and then the CT scans were scored 2 weeks apart by two chest radiologists working independently of one another. Discrepancies were resolved by a third chest radiologist. The scans were scored for bronchiectasis, consolidation or atelectasis, abscess or sacculation, nodules, and mucus plugging using a three-point lobar scale (absent, <50% of lobe, and >50% of lobe). Agreement analyses and ordinary least products regressions were performed. A fixed bias was found between total CT and MRI scores, with CT scoring higher on average (median difference: 4 on a scale of 48; interquartile range: 3, 6). Fixed biases were found for bronchiectasis and consolidation or atelectasis subscale scores. Both fixed and proportional biases were found between CT and MRI mucus plugging scores. No bias was found between CT and MRI nodule scores. There was nearly perfect lobar percent agreement for more conspicuous findings such as consolidation or atelectasis and abscess or sacculation. In this exploratory study of 25 adult patients with culture-proven MAC lung infection, we found moderate agreement between MRI and CT for assessing the anatomic features and lobar extent of disease. Given the feasibility of chest MRI for this condition, future work is

  1. Primary antitumor immune response mediated by CD4+ T cells.

    PubMed

    Corthay, Alexandre; Skovseth, Dag K; Lundin, Katrin U; Røsjø, Egil; Omholt, Hilde; Hofgaard, Peter O; Haraldsen, Guttorm; Bogen, Bjarne

    2005-03-01

    Gene-targeted mice have recently revealed a role for lymphocytes and interferon-gamma (IFNgamma) in conferring protection against cancer, but the mechanisms remain unclear. Here, we have characterized a successful primary antitumor immune response initiated by naive CD4+ T cells. Major histocompatibility complex class II (MHC-II)-negative myeloma cells injected subcutaneously into syngeneic mice were surrounded within 3 days by macrophages that captured tumor antigens. Within 6 days, naive myeloma-specific CD4+ T cells became activated in draining lymph nodes and subsequently migrated to the incipient tumor site. Upon recognition of tumor-derived antigenic peptides presented on MHC-II by macrophages, the myeloma-specific CD4+ T cells were reactivated and started to secrete cytokines. T cell-derived IFNgamma activated macrophages in close proximity to the tumor cells. Tumor cell growth was completely inhibited by such locally activated macrophages. These data indicate a mechanism for immunosurveillance of MHC-II-negative cancer cells by tumor-specific CD4+ T cells through collaboration with macrophages.

  2. CD4+ T cells memorize obesity and promote weight regain.

    PubMed

    Zou, Jianghuan; Lai, Beibei; Zheng, Mingzhu; Chen, Qin; Jiang, Shujun; Song, Anying; Huang, Zan; Shi, Peiliang; Tu, Xin; Wang, Di; Lu, Linrong; Lin, Zhaoyu; Gao, Xiang

    2017-06-19

    Body weight regain often causes failure of obesity therapies while the underlying mechanism remains largely unknown. In this study, we report that immune cells, especially CD4+ T cells, mediate the 'memory' of previous obese status. In a weight gain-loss-regain model, we found that C57BL/6J mice with an obesity history showed a much faster rate of body weight regain. This obesity memory could last for at least 2 months after previously obese mice were kept at the same body weight as non-obese mice. Surprisingly, such obesity memory was abrogated by dexamethasone treatment, whereas immunodeficient Rag1(-/-) and H2A(-/-) mice failed to establish such memory. Rag1(-/-) mice repossessed the obesity memory when immune cells or CD4+ T cells isolated from previously obese mice were transferred. Furthermore, depletion of CD4+ T cells led to obesity memory ablation. Taken together, we conclude that CD4+ T cells mediate obesity memory and promote weight regain.Cellular &Molecular Immunology advance online publication, 19 June 2017; doi:10.1038/cmi.2017.36.

  3. High resolution NMR study of T1 magnetic relaxation dispersion. III. Influence of spin 1/2 hetero-nuclei on spin relaxation and polarization transfer among strongly coupled protons.

    PubMed

    Korchak, Sergey E; Ivanov, Konstantin L; Pravdivtsev, Andrey N; Yurkovskaya, Alexandra V; Kaptein, Robert; Vieth, Hans-Martin

    2012-09-07

    Effects of spin-spin interactions on the nuclear magnetic relaxation dispersion (NMRD) of protons were studied in a situation where spin ½ hetero-nuclei are present in the molecule. As in earlier works [K. L. Ivanov, A. V. Yurkovskaya, and H.-M. Vieth, J. Chem. Phys. 129, 234513 (2008); S. E. Korchak, K. L. Ivanov, A. V. Yurkovskaya, and H.-M. Vieth, ibid. 133, 194502 (2010)], spin-spin interactions have a pronounced effect on the relaxivity tending to equalize the longitudinal relaxation times once the spins become strongly coupled at a sufficiently low magnetic field. In addition, we have found influence of (19)F nuclei on the proton NMRD, although in the whole field range, studied protons and fluorine spins were only weakly coupled. In particular, pronounced features in the proton NMRD were found; but each feature was predominantly observed only for particular spin states of the hetero-nuclei. The features are explained theoretically; it is shown that hetero-nuclei can affect the proton NMRD even in the limit of weak coupling when (i) protons are coupled strongly and (ii) have spin-spin interactions of different strengths with the hetero-nuclei. We also show that by choosing the proper magnetic field strength, one can selectively transfer proton spin magnetization between spectral components of choice.

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

    PubMed

    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.

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

    PubMed Central

    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

  6. Proton magnetic resonance spectroscopy of brain metabolic shifts induced by acute administration of 2-deoxy-d-glucose and lipopolysaccharides.

    PubMed

    Moshkin, Mikhail P; Akulov, Andrey E; Petrovski, Dmitriy V; Saik, Olga V; Petrovskiy, Evgeny D; Savelov, Andrey A; Koptyug, Igor V

    2014-04-01

    In vivo proton magnetic resonance spectroscopy ((1) H MRS) of outbred stock ICR male mice (originating from the Institute of Cancer Research) was used to study the brain (hippocampus) metabolic response to the pro-inflammatory stimulus and to the acute deficiency of the available energy, which was confirmed by measuring the maximum oxygen consumption. Inhibition of glycolysis by means of an injection with 2-deoxy-d-glucose (2DG) reduced the levels of gamma-aminobutyric acid (GABA, p < 0.05, in comparison with control, least significant difference (LSD) test), N-acetylaspartate (NAA, p < 0.05, LSD test) and choline compounds, and at the same time increased the levels of glutamate and glutamine. An opposite effect was found after injection with bacterial lipopolysaccharide (LPS) - a very common pro-inflammatory inducer. An increase in the amounts of GABA, NAA and choline compounds in the brain occurred in mice treated with LPS. Different metabolic responses to the energy deficiency and the pro-inflammatory stimuli can explain the contradictory results of the brain (1) H MRS studies under neurodegenerative pathology, which is accompanied by both mitochondrial dysfunction and inflammation. The prevalence of the excitatory metabolites such as glutamate and glutamine in 2DG treated mice is in good agreement with excitation observed during temporary reduction of the available energy under acute hypoxia or starvation. In turn, LPS, as an inducer of the sickness behavior, which was manifested as depression, sleepiness, loss of appetite etc., shifts the brain metabolic pattern toward the prevalence of the inhibitory neurotransmitter GABA.

  7. Accuracy and stability of measuring GABA, glutamate, and glutamine by proton magnetic resonance spectroscopy: A phantom study at 4 Tesla

    PubMed Central

    Henry, Michael E.; Lauriat, Tara L.; Shanahan, Meghan; Renshaw, Perry F.; Jensen, J. Eric

    2015-01-01

    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. PMID:21130670

  8. Neurochemical alterations in methamphetamine-dependent patients treated with cytidine-5'-diphosphate choline: a longitudinal proton magnetic resonance spectroscopy study.

    PubMed

    Yoon, Sujung J; Lyoo, In Kyoon; Kim, Hengjun J; Kim, Tae-Suk; Sung, Young Hoon; Kim, Namkug; Lukas, Scott E; Renshaw, Perry F

    2010-04-01

    Cytidine-5'-diphosphate choline (CDP-choline), as an important intermediate for major membrane phospholipids, may exert neuroprotective effects in various neurodegenerative disorders. This longitudinal proton magnetic resonance spectroscopy ((1)H-MRS) study aimed to examine whether a 4-week CDP-choline treatment could alter neurometabolite levels in patients with methamphetamine (MA) dependence and to investigate whether changes in neurometabolite levels would be associated with MA use. We hypothesized that the prefrontal levels of N-acetyl-aspartate (NAA), a neuronal marker, and choline-containing compound (Cho), which are related to membrane turnover, would increase with CDP-choline treatment in MA-dependent patients. We further hypothesized that this increase would correlate with the total number of negative urine results. Thirty-one treatment seekers with MA dependence were randomly assigned to receive CDP-choline (n=16) or placebo (n=15) for 4 weeks. Prefrontal NAA and Cho levels were examined using (1)H-MRS before medication, and at 2 and 4 weeks after treatment. Generalized estimating equation regression analyses showed that the rate of change in prefrontal NAA (p=0.005) and Cho (p=0.03) levels were greater with CDP-choline treatment than with placebo. In the CDP-choline-treated patients, changes in prefrontal NAA levels were positively associated with the total number of negative urine results (p=0.03). Changes in the prefrontal Cho levels, however, were not associated with the total number of negative urine results. These preliminary findings suggest that CDP-choline treatment may exert potential neuroprotective effects directly or indirectly because of reductions in drug use by the MA-dependent patients. Further studies with a larger sample size of MA-dependent patients are warranted to confirm a long-term efficacy of CDP-choline in neuroprotection and abstinence.

  9. Diet-Quality Scores and Prevalence of Nonalcoholic Fatty Liver Disease: A Population Study Using Proton-Magnetic Resonance Spectroscopy.

    PubMed

    Chan, Ruth; Wong, Vincent Wai-Sun; Chu, Winnie Chiu-Wing; Wong, Grace Lai-Hung; Li, Liz Sin; Leung, Jason; Chim, Angel Mei-Ling; Yeung, David Ka-Wai; Sea, Mandy Man-Mei; Woo, Jean; Chan, Francis Ka-Leung; Chan, Henry Lik-Yuen

    2015-01-01

    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.

  10. Altered white matter metabolism in delayed neurologic sequelae after carbon monoxide poisoning: A proton magnetic resonance spectroscopic study.

    PubMed

    Kuroda, Hiroshi; Fujihara, Kazuo; Mugikura, Shunji; Takahashi, Shoki; Kushimoto, Shigeki; Aoki, Masashi

    2016-01-15

    Proton magnetic resonance spectroscopy ((1)H-MRS) was recently used to examine altered metabolism in the white matter (WM) of patients experiencing carbon monoxide (CO) poisoning; however, only a small number of patients with delayed neurologic sequelae (DNS) were analyzed. We aimed to detect altered metabolism in the WM of patients with DNS using (1)H-MRS; to explore its clinical relevance in the management of patients experiencing CO poisoning. Patients experiencing acute CO poisoning underwent (1)H-MRS and cerebrospinal fluid (CSF) examination within 1week and at 1month after acute poisoning. Metabolites including choline-containing compounds (Cho), creatine (Cr), N-acetylaspartate (NAA), and lactate were measured from the periventricular WM. Myelin basic protein (MBP) concentrations were measured in CSF. Fifty-two patients experiencing acute CO poisoning (15 with DNS, 37 without DNS; median age, 49years; 65% males) underwent (1)H-MRS. Within 1week, NAA/Cr ratios, reflecting neuroaxonal viability, were lower in patients with DNS than in those without DNS (P<0.05). At 1month, when 9 of 15 patients (60%) developed DNS, Cho/Cr ratios were higher, and NAA/Cr and NAA/Cho ratios lower in patients with DNS (P=0.0001, <0.0001, and <0.0001, respectively), indicating increased membrane metabolism and decreased neuroaxonal viability. (1)H-MRS parameter abnormalities correlated with the elevation of MBP in CSF. The presence of a lactate peak was a predictor for a poor long-term outcome. (1)H-MRS within 1week may be useful for predicting DNS development; (1)H-MRS at 1month may be useful for discriminating patients with DNS and predicting long-term outcomes. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Binge Toluene Exposure Alters Glutamate, Glutamine and GABA in the Adolescent Rat Brain as Measured by Proton Magnetic Resonance Spectroscopy*

    PubMed Central

    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

  12. Proton magnetic resonance spectroscopy assessment of metabolite status of the anterior cingulate cortex in chronic pain patients and healthy controls

    PubMed Central

    Ito, Takahiro; Tanaka-Mizuno, Sachiko; Iwashita, Narihito; Tooyama, Ikuo; Shiino, Akihiko; Miura, Katsuyuki; Fukui, Sei

    2017-01-01

    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 performed on the combination of Glx/tCr, Ins/tCr, and NAA/tCr effectively discriminated chronic pain patients from healthy controls. Patients with higher HADS-Depression scores had increased Glx/rCr levels (p=0.015), and those with higher HADS-Anxiety scores had increased NAA/tCr levels (p=0.018). Conclusion Chronic pain patients have a different metabolite status in the anterior cingulate cortex to controls. Within the pain patient group, HADS scores had a positive relationship with NAA/tCr and Glx/tCr levels. 1H-MRS successfully detected metabolic changes in patients’ brains in a noninvasive manner, revealing its potential as a superior diagnostic tool for pain patients. PMID:28203104

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

    PubMed Central

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

    2014-01-01

    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 (1H 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. 1H NMR is less sensitive but sample preparation is generally faster and analysis times shorter, resulting in markedly lower analysis costs. 1H NMR is robust, reproducible and can provide absolute quantitation of many metabolites. Of particular relevance to cardio-metabolic disease is the ability of 1H 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 1H NMR; compares MS and 1H NMR and provides a tabular overview of recent 1H NMR-based research findings in the atherosclerosis field, describing the design and scope of studies conducted to date. 1H 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. PMID:25299963

  14. Dose-Volume Differences for Computed Tomography and Magnetic Resonance Imaging Segmentation and Planning for Proton Prostate Cancer Therapy

    SciTech Connect

    Yeung, Anamaria R.; Vargas, Carlos E. Falchook, Aaron; Louis, Debbie C.; Olivier, Kenneth; Keole, Sameer; Yeung, Daniel; Mendenhall, Nancy P.; Li Zuofeng

    2008-12-01

    Purpose: To determine the influence of magnetic-resonance-imaging (MRI)-vs. computed-tomography (CT)-based prostate and normal structure delineation on the dose to the target and organs at risk during proton therapy. Methods and Materials: Fourteen patients were simulated in the supine position using both CT and T2 MRI. The prostate, rectum, and bladder were delineated on both imaging modalities. The planning target volume (PTV) was generated from the delineated prostates with a 5-mm axial and 8-mm superior and inferior margin. Two plans were generated and analyzed for each patient: an MRI plan based on the MRI-delineated PTV, and a CT plan based on the CT-delineated PTV. Doses of 78 Gy equivalents (GE) were prescribed to the PTV. Results: Doses to normal structures were lower when MRI was used to delineate the rectum and bladder compared with CT: bladder V50 was 15.3% lower (p = 0.04), and rectum V50 was 23.9% lower (p = 0.003). Poor agreement on the definition of the prostate apex was seen between CT and MRI (p = 0.007). The CT-defined prostate apex was within 2 mm of the apex on MRI only 35.7% of the time. Coverage of the MRI-delineated PTV was significantly decreased with the CT-based plan: the minimum dose to the PTV was reduced by 43% (p < 0.001), and the PTV V99% was reduced by 11% (p < 0.001). Conclusions: Using MRI to delineate the prostate results in more accurate target definition and a smaller target volume compared with CT, allowing for improved target coverage and decreased doses to critical normal structures.

  15. Proton magnetic resonance studies on peptide fragments of troponin-C containing single calcium-binding sites.

    PubMed

    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.

  16. Frontal Cortex Myo-Inositol Is Associated with Sleep and Depression in Adolescents: A Proton Magnetic Resonance Spectroscopy Study.

    PubMed

    Urrila, Anna S; Hakkarainen, Antti; Castaneda, Anu; Paunio, Tiina; Marttunen, Mauri; Lundbom, Nina

    2017-08-10

    This study used proton magnetic resonance spectroscopy (1H MRS) to evaluate the neurochemistry of the frontal cortex in adolescents with symptoms of sleep and depression. Nineteen non-medicated adolescent boys (mean age 16.0 years; 9 clinical cases with depression/sleep symptoms and 10 healthy controls) underwent 1H MRS at 3 T. MR spectra were acquired from the anterior cingulate cortex (ACC), the dorsolateral prefrontal cortex, and frontal white matter. Concentrations of N-acetyl aspartate, total creatine, choline-containing compounds, total glutamine plus glutamate, and myo-inositol (mI) were compared in the 2 subgroups, and correlated with sleep and clinical measures in the total sample. Sleep was assessed with self-report questionnaires and ambulatory polysomnography recordings. Concentrations of mI were lower in both frontal cortical regions among the depressed adolescents than in controls. No statistically significant differences in other metabolite concentrations were observed between the subgroups. Frontal cortex mI concentrations correlated negatively with depression severity, subjective daytime sleepiness, insomnia symptoms, and the level of anxiety, and correlated positively with total sleep time and overall psychosocial functioning. The correlations between mI in the ACC and total sleep time as well as daytime sleepiness remained statistically significant when depression severity was controlled in the analyses. Lower frontal cortex mI may indicate a disturbed second messenger system. Frontal cortical mI may thus be linked to the pathophysiology of depression and concomitant sleep symptoms among maturing adolescents. Short sleep and daytime sleepiness may be associated with frontal cortex mI independently from depression. © 2017 S. Karger AG, Basel.

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

    NASA Astrophysics Data System (ADS)

    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.

  18. Metabolite profile in the basal ganglia of children with cerebral palsy: a proton magnetic resonance spectroscopy study.

    PubMed

    Kulak, Wojciech; Sobaniec, Wojciech; Smigielska-Kuzia, Joanna; Kubas, Bozena; Walecki, Jerzy

    2006-04-01

    This prospective study determined metabolite profile in the left and right basal ganglia of children with spastic cerebral palsy (CP) compared with children without disabilities, by using proton magnetic resonance spectroscopy (1HMRS). Twenty-three patients with spastic CP (12 males, 11 females; mean age 11y 9mo [SD 4y 2mo], range 4-17y) were examined. Twenty children had spastic diplegia and three had quadriplegia. Twenty-four normally developing children (13 females, 11 males; mean age 10y 3mo [SD 4y 8mo], range 4-17y) served as a comparison group. The relative concentrations of N-acetylaspartate (NAA), choline (Cho), myo-inositol (mI), and gamma-aminobutyric acid (GABA) were measured relative to creatine (Cr) and different combinations of metabolites within 8cm3 brain voxels. Children with CP showed reduced ratios of NAA:Cr, NAA:Cho, NAA:mI, and GABA:Cr in the basal ganglia relative to a matched comparison group. Patients demonstrated a significant age-dependent increase in NAA:Cr and NAA:Cho in the basal ganglia. No sex-dependent difference was shown in children with CP nor in the comparison group for all tested metabolite ratios. Significant correlation between Apgar score and ratio of mI:Cr in the group with CP was found. None of the tested metabolite ratios were correlated with the severity scale of CP in children with CP. NAA:Cr ratios were negatively correlated with learning disability in patients with CP. Results indicate the association of the metabolite ratios in basal ganglia with learning disability.

  19. Diet-Quality Scores and Prevalence of Nonalcoholic Fatty Liver Disease: A Population Study Using Proton-Magnetic Resonance Spectroscopy

    PubMed Central

    Chan, Ruth; Wong, Vincent Wai-Sun; Chu, Winnie Chiu-Wing; Wong, Grace Lai-Hung; Li, Liz Sin; Leung, Jason; Chim, Angel Mei-Ling; Yeung, David Ka-Wai; Sea, Mandy Man-Mei; Woo, Jean; Chan, Francis Ka-Leung; Chan, Henry Lik-Yuen

    2015-01-01

    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. PMID:26418083

  20. Accuracy and stability of measuring GABA, glutamate, and glutamine by proton magnetic resonance spectroscopy: A phantom study at 4 Tesla

    NASA Astrophysics Data System (ADS)

    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.

  1. Investigation of Heschl's Gyrus and Planum Temporale in Patients with Schizophrenia and Bipolar Disorder: a Proton Magnetic Resonance Spectroscopy Study

    PubMed Central

    Atagün, M.İ.; Şıkoğlu, E.M.; Can, S.S.; Karakaş-Uğurlu, G.; Ulusoy-Kaymak, S.; Çayköylü, A.; Algın, O.; Phillips, M.L.; Moore, C.M.; Öngür, D.

    2014-01-01

    Background Superior temporal cortices include brain regions dedicated to auditory processing and several lines of evidence suggest structural and functional abnormalities in both schizophrenia and bipolar disorder within this brain region. However, possible glutamatergic dysfunction within this region has not been investigated in adult patients. Methods Thirty patients with schizophrenia (38.67 ± 12.46 years of age), 28 euthymic patients with bipolar I disorder (35.32 ± 9.12 years of age), and 30 age-, gender- and education- matched healthy controls were enrolled. Proton Magnetic Resonance Spectroscopy data were acquired using a 3.0T Siemens MAGNETOM TIM Trio MR system and single voxel Point REsolved Spectroscopy Sequence (PRESS) in order to quantify brain metabolites within the left and right Heschl's Gyrus and Planum Temporale of superior temporal cortices. Results There were significant abnormalities in Glutamate (Glu) (F(2,78)=8.52, p<0.0001), n-Acetyl Aspartate (tNAA) (F(2,81)=5.73, p=0.005), Creatine (tCr) (F(2,83)=5.91, p=0.004) and Inositol (Ins) (F(2,82)=8.49, p<0.0001) concentrations in the left superior temporal cortex. In general, metabolite levels were lower for bipolar disorder patients when compared to healthy participants. Moreover, patients with bipolar disorder exhibited significantly lower tCr and Ins concentrations when compared to schizophrenia patients. In addition, we have found significant correlations between the superior temporal cortex metabolites and clinical measures. Conclusion As the left auditory cortices are associated with language and speech, left hemisphere specific abnormalities may have clinical significance. Our findings are suggestive of shared glutamatergic abnormalities in schizophrenia and bipolar disorder. PMID:25480359

  2. Multimodality imaging using proton magnetic resonance spectroscopic imaging and 18F-fluorodeoxyglucose-positron emission tomography in local prostate cancer

    PubMed Central

    Shukla-Dave, Amita; Wassberg, Cecilia; Pucar, Darko; Schöder, Heiko; Goldman, Debra A; Mazaheri, Yousef; Reuter, Victor E; Eastham, James; Scardino, Peter T; Hricak, Hedvig

    2017-01-01

    AIM To assess the relationship using multimodality imaging between intermediary citrate/choline metabolism as seen on proton magnetic resonance spectroscopic imaging (1H-MRSI) and glycolysis as observed on 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) in prostate cancer (PCa) patients. METHODS The study included 22 patients with local PCa who were referred for endorectal magnetic resonance imaging/1H-MRSI (April 2002 to July 2007) and 18F-FDG-PET/CT and then underwent prostatectomy as primary or salvage treatment. Whole-mount step-section pathology was used as the standard of reference. We assessed the relationships between PET parameters [standardized uptake value (SUVmax and SUVmean)] and MRSI parameters [choline + creatine/citrate (CC/Cmax and CC/Cmean) and total number of suspicious voxels] using spearman’s rank correlation, and the relationships of PET and 1H-MRSI index lesion parameters to surgical Gleason score. RESULTS Abnormal intermediary metabolism on 1H-MRSI was present in 21/22 patients, while abnormal glycolysis on 18F-FDG-PET/CT was detected in only 3/22 patients. Specifically, index tumor localization rates were 0.95 (95%CI: 0.77-1.00) for 1H-MRSI and 0.14 (95%CI: 0.03-0.35) for 18F-FDG-PET/CT. Spearman rank correlations indicated little relationship (ρ = -0.36-0.28) between 1H-MRSI parameters and 18F-FDG-PET/CT parameters. Both the total number of suspicious voxels (ρ = 0.55, P = 0.0099) and the SUVmax (ρ = 0.46, P = 0.0366) correlated weakly with the Gleason score. No significant relationship was found between the CC/Cmax, CC/Cmean or SUVmean and the Gleason score (P = 0.15-0.79). CONCLUSION The concentration of intermediary metabolites detected by 1H MRSI and glycolytic flux measured 18F-FDG PET show little correlation. Furthermore, only few tumors were FDG avid on PET, possibly because increased glycolysis represents a late and rather ominous event in the progression of PCa. PMID:28396727

  3. Protonation of carbon single-walled nanotubes studied using 13C and 1H-13C cross polarization nuclear magnetic resonance and Raman spectroscopies.

    PubMed

    Engtrakul, Chaiwat; Davis, Mark F; Gennett, Thomas; Dillon, Anne C; Jones, Kim M; Heben, Michael J

    2005-12-14

    The reversible protonation of carbon single-walled nanotubes (SWNTs) in sulfuric acid and Nafion was investigated using solid-state nuclear magnetic resonance (NMR) and Raman spectroscopies. Magic-angle spinning (MAS) was used to obtain high-resolution 13C and 1H-13C cross polarization (CP) NMR spectra. The 13C NMR chemical shifts are reported for bulk SWNTs, H2SO4-treated SWNTs, SWNT-Nafion polymer composites, SWNT-AQ55 polymer composites, and SWNTs in contact with water. Protonation occurs without irreversible oxidation of the nanotube substrate via a charge-transfer process. This is the first report of a chemically induced change in a SWNT 13C resonance brought about by a reversible interaction with an acidic proton, providing additional evidence that carbon nanotubes behave as weak bases. Cross polarization was found to be a powerful technique for providing an additional contrast mechanism for studying nanotubes in contact with other chemical species. The CP studies confirmed polarization transfer from nearby protons to nanotube carbon atoms. The CP technique was also applied to investigate water adsorbed on carbon nanotube surfaces. Finally, the degree of bundling of the SWNTs in Nafion films was probed with the 1H-13C CP-MAS technique.

  4. Graphene oxide-Fe{sub 3}O{sub 4} nanoparticle composite with high transverse proton relaxivity value for magnetic resonance imaging

    SciTech Connect

    Venkatesha, N.; Srivastava, Chandan; Poojar, Pavan; Geethanath, Sairam; Qurishi, Yasrib

    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.

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

    PubMed

    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 < 0.0001), abdominal total adipose tissue volume by 10.45% (p = 0.001), and abdominal visceral to subcutaneous fat ratio by 10.59% (p = 0.007). Decreases in body weight (-2.13%), waist circumference (-1.44%), hip circumference (-0.33%), waist-to-hip ratio (WHR) (-0.99%), abdominal subcutaneous adipose tissue (SAT) volume (-5.63%), and intrahepatic triglyceride (IHTG) content (-9.03%) were also observed, although these were not significant (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

  6. 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.

    PubMed

    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.

  7. 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

    NASA Technical Reports Server (NTRS)

    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.

  8. Amide proton exchange in the. cap alpha. -amylase polypeptide inhibitor tendamistat studied by two-dimensional /sup 1/H nuclear magnetic resonance

    SciTech Connect

    Wang, O.; Kline, A.D.; Wuethrich, K.

    1987-10-06

    The individual amide proton exchange rates in Tendamistat at pH 3.0 and 50/sup 0/C were measured by using two-dimensional ..cap alpha..H nuclear magnetic resonance. Overall, it was found that the distribution of exchange rates along the sequence is dominated by the interstrand hydrogen bonds of the ..beta..-sheet structures. The slowly exchanging protons in the core of the two ..beta..-sheets were shown to exchange via an EX2 mechanism. Further analysis of the data indicates that different large-scale structure fluctuations are responsible for the exchange from the two ..beta..-sheets, even though the three-dimensional structure of Tendamistat appears to consist of a single structural domain.

  9. Proton magnetic resonance imaging of diffusion of high- and low-molecular-weight contrast agents in opaque porous media saturated with water.

    PubMed

    Osuga, T; Han, S

    2004-09-01

    Besides their use in contrast-enhanced proton magnetic resonance imaging (MRI), contrast agents were found to be useful as tracer molecules. Since paramagnetic ions in water have the ability to reduce the T1 of protons around them, MRI can determine the locations of Mn2+ and Gd3+ of ppm concentration in water. In opaque porous media saturated with water, MRI revealed diffusional motions of three contrast agents: MnCl2 (molecular-weight [M.W.], 126), gadolinium-diethylene-triaminepenta acetic acid (Gd-DTPA) (M.W., 743) and albumin (Gd-DTPA) (M.W., 94,000) at a diffusional displacement ratio of 9:5:2. With the aid of these contrast agents, the transport of low- to high-molecular-weight molecules in opaque water media such as living bodies can be observed using MRI.

  10. Magnetization transfer from laser-polarized xenon to protons located in the hydrophobic cavity of the wheat nonspecific lipid transfer protein

    PubMed Central

    Landon, Céline; Berthault, Patrick; Vovelle, Françoise; Desvaux, Hervé

    2001-01-01

    Nonspecific lipid transfer protein from wheat is studied by liquid-state NMR in the presence of xenon. The gas–protein interaction is indicated by the dependence of the protein proton chemical shifts on the xenon pressure and formally confirmed by the first observation of magnetization transfer from laser-polarized xenon to the protein protons. Twenty-six heteronuclear nOes have allowed the characterization of four interaction sites inside the wheat ns-LTP cavity. Their locations are in agreement with the variations of the chemical shifts under xenon pressure and with solvation simulations. The richness of the information obtained by the noble gas with a nuclear polarization multiplied by ∼12,000 makes this approach based on dipolar cross-relaxation with laser-polarized xenon promising for probing protein hydrophobic pockets at ambient pressure. PMID:11274467

  11. CD4 T-Cell Memory Generation and Maintenance

    PubMed Central

    Gasper, David J.; Tejera, Melba Marie; Suresh, M.

    2014-01-01

    Immunologic memory is the adaptive immune system's powerful ability to remember a previous antigen encounter and react with accelerated vigor upon antigen re-exposure. It provides durable protection against reinfection with pathogens and is the foundation for vaccine-induced immunity. Unlike the relatively restricted immunologic purview of memory B cells and CD8 T cells, the field of CD4 T-cell memory must account for multiple distinct lineages with diverse effector functions, the issue of lineage commitment and plasticity, and the variable distribution of memory cells within each lineage. Here, we discuss the evidence for lineage-specific CD4 T-cell memory and summarize the known factors contributing to memory-cell generation, plasticity, and long-term maintenance. PMID:24940912

  12. CD4 T-cell memory generation and maintenance.

    PubMed

    Gasper, David J; Tejera, Melba Marie; Suresh, M

    2014-01-01

    Immunologic memory is the adaptive immune system's powerful ability to remember a previous antigen encounter and react with accelerated vigor upon antigen re-exposure. It provides durable protection against reinfection with pathogens and is the foundation for vaccine-induced immunity. Unlike the relatively restricted immunologic purview of memory B cells and CD8 T cells, the field of CD4 T-cell memory must account for multiple distinct lineages with diverse effector functions, the issue of lineage commitment and plasticity, and the variable distribution of memory cells within each lineage. Here, we discuss the evidence for lineage-specific CD4 T-cell memory and summarize the known factors contributing to memory-cell generation, plasticity, and long-term maintenance.

  13. Human CD4+ T Cell Response to Human Herpesvirus 6

    PubMed Central

    Nastke, Maria-D.; Becerra, Aniuska; Yin, Liusong; Dominguez-Amorocho, Omar; Gibson, Laura; Calvo-Calle, J. Mauricio

    2012-01-01

    Following primary infection, human herpesvirus 6 (HHV-6) establishes a persistent infection for life. HHV-6 reactivation has been associated with transplant rejection, delayed engraftment, encephalitis, muscular dystrophy, and drug-induced hypersensitivity syndrome. The poor understanding of the targets and outcome of the cellular immune response to HHV-6 makes it difficult to outline the role of HHV-6 in human disease. To fill in this gap, we characterized CD4 T cell responses to HHV-6 using peripheral blood mononuclear cell (PBMC) and T cell lines generated from healthy donors. CD4+ T cells responding to HHV-6 in peripheral blood were observed at frequencies below 0.1% of total T cells but could be expanded easily in vitro. Analysis of cytokines in supernatants of PBMC and T cell cultures challenged with HHV-6 preparations indicated that gamma interferon (IFN-γ) and interleukin-10 (IL-10) were appropriate markers of the HHV-6 cellular response. Eleven CD4+ T cell epitopes, all but one derived from abundant virion components, were identified. The response was highly cross-reactive between HHV-6A and HHV-6B variants. Seven of the CD4+ T cell epitopes do not share significant homologies with other known human pathogens, including the closely related human viruses human herpesvirus 7 (HHV-7) and human cytomegalovirus (HCMV). Major histocompatibility complex (MHC) tetramers generated with these epitopes were able to detect HHV-6-specific T cell populations. These findings provide a window into the immune response to HHV-6 and provide a basis for tracking HHV-6 cellular immune responses. PMID:22357271

  14. An atlas of mouse CD4(+) T cell transcriptomes.

    PubMed

    Stubbington, Michael Jt; Mahata, Bidesh; Svensson, Valentine; Deonarine, Andrew; Nissen, Jesper K; Betz, Alexander G; Teichmann, Sarah A

    2015-04-03

    CD4(+) T cells are key regulators of the adaptive immune system and can be divided into T helper (Th) cells and regulatory T (Treg) cells. During an immune response Th cells mature from a naive state into one of several effector subtypes that exhibit distinct functions. The transcriptional mechanisms that underlie the specific functional identity of CD4(+) T cells are not fully understood. To assist investigations into the transcriptional identity and regulatory processes of these cells we performed mRNA-sequencing on three murine T helper subtypes (Th1, Th2 and Th17) as well as on splenic Treg cells and induced Treg (iTreg) cells. Our integrated analysis of this dataset revealed the gene expression changes associated with these related but distinct cellular identities. Each cell subtype differentially expresses a wealth of 'subtype upregulated' genes, some of which are well known whilst others promise new insights into signalling processes and transcriptional regulation. We show that hundreds of genes are regulated purely by alternative splicing to extend our knowledge of the role of post-transcriptional regulation in cell differentiation. This CD4(+) transcriptome atlas provides a valuable resource for the study of CD4(+) T cell populations. To facilitate its use by others, we have made the data available in an easily accessible online resource at www.th-express.org.

  15. CD4+ T Cells: guardians of the phagosome.

    PubMed

    Tubo, Noah J; Jenkins, Marc K

    2014-04-01

    CD4(+) T cells are key cells of the adaptive immune system that use T cell antigen receptors to recognize peptides that are generated in endosomes or phagosomes and displayed on the host cell surface bound to major histocompatibility complex molecules. These T cells participate in immune responses that protect hosts from microbes such as Mycobacterium tuberculosis, Cryptococcus neoformans, Leishmania major, and Salmonella enterica, which have evolved to live in the phagosomes of macrophages and dendritic cells. Here, we review studies indicating that CD4(+) T cells control phagosomal infections asymptomatically in most individuals by secreting cytokines that activate the microbicidal activities of infected phagocytes but in a way that inhibits the pathogen but does not eliminate it. Indeed, we make the case that localized, controlled, persistent infection is necessary to maintain large numbers of CD4(+) effector T cells in a state of activation needed to eradicate systemic and more pathogenic forms of the infection. Finally, we posit that current vaccines for phagosomal infections fail because they do not produce this "periodic reminder" form of CD4(+) T cell-mediated immune control.

  16. Cellular Plasticity of CD4+ T Cells in the Intestine

    PubMed Central

    Brucklacher-Waldert, Verena; Carr, Edward J.; Linterman, Michelle A.; Veldhoen, Marc

    2014-01-01

    Barrier sites such as the gastrointestinal tract are in constant contact with the environment, which contains both beneficial and harmful components. The immune system at the epithelia must make the distinction between these components to balance tolerance, protection, and immunopathology. This is achieved via multifaceted immune recognition, highly organized lymphoid structures, and the interaction of many types of immune cells. The adaptive immune response in the gut is orchestrated by CD4+ helper T (Th) cells, which are integral to gut immunity. In recent years, it has become apparent that the functional identity of these Th cells is not as fixed as initially thought. Plasticity in differentiated T cell subsets has now been firmly established, in both health and disease. The gut, in particular, utilizes CD4+ T cell plasticity to mold CD4+ T cell phenotypes to maintain its finely poised balance of tolerance and inflammation and to encourage biodiversity within the enteric microbiome. In this review, we will discuss intestinal helper T cell plasticity and our current understanding of its mechanisms, including our growing knowledge of an evolutionarily ancient symbiosis between microbiota and malleable CD4+ T cell effectors. PMID:25339956

  17. H-1 Dynamic Nuclear Polarization in Supercritical Ethylene at 1.4 T

    SciTech Connect

    Wind, Robert A. ); Shi, Bai; Hu, Jian Zhi ); Solum, Mark S.; Ellis, Paul D. ); Grant, David M.; Pugmire, Ronald J.; Taylor, Craig M.; Yonker, Clement R. )

    2000-03-01

    H1 dynamic nuclear polarization (DNP) has been measured in supercritical ethylene in the pressure range 60-300 bar and in an external field of 1.4 T. A single-cell sapphire tube was used as a high pressure cell and powdered 1,3-bisdiphenylene-2-phenyl allyl(BDPA) free radicals were added and distributed at the wall of the cell. At all pressures the dominant DNP effect was a positive Overhauser enhancement, caused by proton-electron contact interactions at the fluid/solid radical interface. The observed enhancements varied from 12 at 67 bar to 17 at 300 bar. Besides the Overhauser enhancement, also a small solid state and thermal mixing enhancement were observed, indicating that part of the ethylene is absorbed at the radical surface for a prolonged time. These data indicate that DNP-enhanced NMR has the potential of extending the impact of NMR in research areas involving supercritical fluids.

  18. Design and evaluation of an RF front-end for 9.4 T human MRI.

    PubMed

    Shajan, G; Hoffmann, Jens; Budde, Juliane; Adriany, Gregor; Ugurbil, Kamil; Pohmann, Rolf

    2011-08-01

    At the field strength of 9.4 T, the highest field currently available for human MRI, the wavelength of the MR signals is significantly shorter than the size of the examined structures. Even more than at 7 T, constructive and destructive interferences cause strong inhomogeneities of the B1 field produced by a volume coil, causing shading over large parts of the image. Specialized radio frequency hardware and B1 management methods are required to obtain high-quality images that take full advantage of the high field strength. Here, the design and characteristics of a radio frequency front-end especially developed for proton imaging at 9.4 T are presented. In addition to a 16-channel transceiver array coil, capable of volume transmit mode and independent signal reception, it consists of custom built low noise preamplifiers and TR switches. Destructive interference patterns were eliminated, in virtually the entire brain, using a simple in situ radio frequency phase shimming technique. After mapping the B1+ profile of each transmit channel, a numerical algorithm was used to calculate the appropriate transmit phase offsets needed to obtain a homogeneous excitation field over a user defined region. Between two and three phase settings are necessary to obtain homogeneous images over the entire brain. Copyright © 2011 Wiley-Liss, Inc.

  19. Proton nuclear magnetic resonance studies of hemoglobin M Milwaukee and their implications concerning the mechanism of cooperative oxygenation of hemoglobin.

    PubMed

    Fung, L W; Minton, A P; Lindstrom, T R; Pisciotta, A V; Ho, C

    1977-04-05

    Hemoglobin M Milwaukee (beta67E11 Val leads to Glu) is a naturally occurring valency hybrid containing two permanently oxidized hemes on the beta chains. In this mutant, the two abnormal beta chains cannot combine with ligands whereas the two alpha chains are normal and can combine with oxygen with a Hill coefficient varying from 1.1 to 1.3 [Udem et al. (1970), J Mol. Biol. 48, 489]. High-resolution proton nuclear magnetic resonance spectroscopy at 250 MHz has been used to investigate the exchangeable, ring-current shifted, ferrous and ferric hyperfine shifted resonances of Hb M Milwaukee in the absence and presence of organic phosphates. The alpha-heme environment, as manifested by the ring-current shifted resonances in the liganded form as well as the ferrous hyperfine shifted resonances in unliganded form, and subunit interactions, as manifested by the exchangeable resonances, are similar in Hb M Milwaukee to those in normal adult human hemoglobin. Organic phosphates can partially or completely inhibit the structural transformation which normally accompanies the binding of oxygen or carbon monoxide to Hb M Milwaukee. Upon stepwise addition of oxygen to deoxy Hb M Milwaukee, the hyperfine shifted resonance spectra of ferric beta chains show features which cannot be attributed to either fully deoxy or oxy species. However, the spectra for partially oxygenated Hb M Milwaukee can be described as an appropriately weighted average of the spectra of sero, singly, and doubly oxygenated species. The ferric hyperfine shifted resonance spectrum of the singly oxygenated intermediate has been calculated by a method employing least-squares analysis of the spectra of partially oxygenated Hb M Milwaukee at several values of oxygen saturation. The spectrum of this intermediate exhibits features which cannot be accounted for by a two-structure model. The present results are consistent with a sequential model for the oxygenation of this mutant hemoglobin. In view of the

  20. Similarities of biochemical abnormalities between major depressive disorder and bipolar depression: a proton magnetic resonance spectroscopy study.

    PubMed

    Zhong, Shuming; Wang, Ying; Zhao, Guoxiang; Xiang, Qi; Ling, Xueying; Liu, Sirun; Huang, Li; Jia, Yanbin

    2014-10-01

    Depression in the context of bipolar disorder (BD) is often misdiagnosed as major depressive disorder (MDD), leading to mistreatments and poor clinical outcomes for many bipolar patients. Previous neuroimaging studies found mixed results on brain structure, and biochemical metabolism of the two disorders. To eliminate the compounding effects of medication, and aging, this study sought to investigate the brain biochemical changes of treatment-naïve, non-late-life patients with MDD and BD in white matter in prefrontal (WMP) lobe, anterior cingulate cortex (ACC) and hippocampus by using proton magnetic resonance spectroscopy ((1)H-MRS). Three groups of participants were recruited: 26 MDD patients, 20 depressed BD patients, and 13 healthy controls. The multi-voxel (1)H-MRS [repetition time (TR)=1000ms; echo-time (TE)=144ms] was used for the measurement of N-acetylaspartate(NAA), choline containg compounds (Cho), and creatine (Cr) in three brain locations: white matter in prefrontal (WMP) lobe, anterior cingulate cortex (ACC), and hippocampus. Two ratios of NAA/Cr and Cho/Cr as a measure of brain biochemical changes were compared among three experimental groups. On the comparison of brain biochemical changes, both MDD patients and BD patients showed many similarities compared to the controls. They both had a significantly lower NAA/Cr ratio in the left WMP lobe. There were no significant differences among three experimental groups for Cho/Cr ratio in the WMP lobe, and for the ratios of NAA/Cr and Cho/Cr in the bilateral ACC and hippocampus. The only difference between MDD and BD patients existed for the NAA/Cr ratio in the right WMP lobe. While MDD patients had a significantly lower NAA/Cr ratio than controls, BD patients showed no such differences. On the comparison of correlation of medical variables and brain biochemical changes, all participants demonstrated no significant correlations. Reduced NAA/Cr ratio at the left WMP lobe indicated the dysfunction of neuronal

  1. Measurements of the generalized electric and magnetic polarizabilities of the proton at low Q2 using the virtual Compton scattering reaction

    NASA Astrophysics Data System (ADS)

    Bourgeois, P.; Sato, Y.; Shaw, J.; Alarcon, R.; Bernstein, A. M.; Bertozzi, W.; Botto, T.; Calarco, J.; Casagrande, F.; Distler, M. O.; Dow, K.; Farkondeh, M.; Georgakopoulos, S.; Gilad, S.; Hicks, R.; Holtrop, M.; Hotta, A.; Jiang, X.; Karabarbounis, A.; Kirkpatrick, J.; Kowalski, S.; Milner, R.; Miskimen, R.; Nakagawa, I.; Papanicolas, C. N.; Sarty, A. J.; Sirca, S.; Six, E.; Sparveris, N. F.; Stave, S.; Stiliaris, E.; Tamae, T.; Tsentalovich, G.; Tschalaer, C.; Turchinetz, W.; Zhou, Z.-L.; Zwart, T.

    2011-09-01

    Experimental details of a virtual Compton scattering (VCS) experiment performed on the proton at the MIT-Bates out-of-plane scattering facility are presented. The VCS response functions PLL-PTT/PTTɛɛ and PLT have been measured at Q2=0.057GeV2/c2. The generalized electric and magnetic polarizabilities, α(Q2) and β(Q2), and the mean-square electric polarizability radius are obtained from a dispersion analysis of the data. The results are in good agreement with O(p3) heavy baryon chiral perturbation and indicate the dominance of mesonic effects in the polarizabilities.

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

    NASA Technical Reports Server (NTRS)

    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.

  3. Cytotoxic activity of CD4+ T cells against autologous tumor cells.

    PubMed

    Konomi, Y; Sekine, T; Takayama, T; Fuji, M; Tanaka, T

    1995-09-01

    The 51Cr-release assay is mostly applied to detecting the cytotoxic activity of CD8+ T cells, and little is known about the activity of CD4+ T cells. Therefore, the correlation between the cytotoxic activity of CD4+ or CD8+ T cells and the incubation period with autologous tumor cells was analyzed by two methods. The incubation periods were 4 and 20 h (4 h and 20 h assay) for the 51Cr-release assay. Eight pairs of tumor cells and T cells were assayed. T cells were fractionated into CD4+ and CD8+ T cells by using magnetic beads and panning methods, and those cells were activated by culture with recombinant interleukin-2 and immobilized anti-CD3 monoclonal antibody. In 6 out of 8 cases, no cytotoxic activity of CD4+ T cells was detected by the 4 h assay, whereas cytotoxic activity was detected in all cases in the 20 h assay. The cytotoxic activities in 20 h assay of CD4+ T cells were increased 67-fold in comparison with the activities in 4 h assay (range: 5-197). In the case of CD8+ T cells, cytotoxic activities were detected in 6 out of 8 cases in the 4 h assay. The lytic unit ratio of CD4+ and CD8+ T cells was calculated as 1.5 in the 20 h assay (range: 0.2- > 7.2) versus 0.4 in the 4 h assay (range: < 0.1-1.3). Cytotoxic activities in colorimetric assay using Crystal Violet with a 24 h incubation were similar to those in the 20 h 51Cr-release assay in all eight cases. These results indicate that CD4+ T cells have cytotoxic activity as strong as that of CD8+ T cells towards autologous tumor cells.

  4. Dual-echo Z-shimmed proton resonance frequency-shift magnetic resonance thermometry near metallic ablation probes: Technique and temperature precision.

    PubMed

    Zhang, Yuxin; Poorman, Megan E; Grissom, William A

    2017-02-10

    To improve the precision of proton resonance frequency-shift magnetic resonance thermometry near ablation probes by recovering near-probe image signals that are typically lost due to magnetic susceptibility-induced field distortions. A dual-echo gradient-recalled echo sequence was implemented, in which the first echo was under- or over-refocused in the slice dimension to recover image signal and temperature precision near a probe, and the second echo was fully refocused to obtain image signal everywhere else in the slice. A penalized maximum likelihood algorithm was implemented to estimate a single temperature map from both echoes. Agar phantom and ex vivo experiments with and without microwave heating at 3 T evaluated how much temperature precision was improved near a microwave ablator compared to a conventional single-echo scan as a function of slice and needle orientation in the magnet. The number of near-probe voxels with temperature standard deviation σ>1°C was decreased by 51% in the phantom experiment, averaged across orientations, and by 31% in the pork. Temperature maps near the probe were more smoother and more complete in all orientations. Dual-echo z-shimmed temperature imaging can recover image signal for more precise temperature mapping near metallic ablation probes. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  5. Theoretical evaluation of structural models of the S2 state in the oxygen evolving complex of Photosystem II: protonation states and magnetic interactions.

    PubMed

    Ames, William; Pantazis, Dimitrios A; Krewald, Vera; Cox, Nicholas; Messinger, Johannes; Lubitz, Wolfgang; Neese, Frank

    2011-12-14

    Protonation states of water ligands and oxo bridges are intimately involved in tuning the electronic structures and oxidation potentials of the oxygen evolving complex (OEC) in Photosystem II, steering the mechanistic pathway, which involves at least five redox state intermediates S(n) (n = 0-4) resulting in the oxidation of water to molecular oxygen. Although protons are practically invisible in protein crystallography, their effects on the electronic structure and magnetic properties of metal active sites can be probed using spectroscopy. With the twin purpose of aiding the interpretation of the complex electron paramagnetic resonance (EPR) spectroscopic data of the OEC and of improving the view of the cluster at the atomic level, a complete set of protonation configurations for the S(2) state of the OEC were investigated, and their distinctive effects on magnetic properties of the cluster were evaluated. The most recent X-ray structure of Photosystem II at 1.9 Å resolution was used and refined to obtain the optimum structure for the Mn(4)O(5)Ca core within the protein pocket. Employing this model, a set of 26 structures was constructed that tested various protonation scenarios of the water ligands and oxo bridges. Our results suggest that one of the two water molecules that are proposed to coordinate the outer Mn ion (Mn(A)) of the cluster is deprotonated in the S(2) state, as this leads to optimal experimental agreement, reproducing the correct ground state spin multiplicity (S = 1/2), spin expectation values, and EXAFS-derived metal-metal distances. Deprotonation of Ca(2+)-bound water molecules is strongly disfavored in the S(2) state, but dissociation of one of the two water ligands appears to be facile. The computed isotropic hyperfine couplings presented here allow distinctions between models to be made and call into question the assumption that the largest coupling is always attributable to Mn(III). The present results impose limits for the total charge

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

    PubMed

    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

  7. A multi-slot surface coil for MRI of dual-rat imaging at 4 T

    NASA Astrophysics Data System (ADS)

    Solis, S. E.; Wang, R.; Tomasi, D.; Rodriguez, A. O.

    2011-06-01

    A slotted surface coil inspired by the hole-and-slot cavity magnetron was developed for magnetic resonance imaging of obese rats at 4 T. Full-wave analysis of the magnetic field was carried out at 170 MHz for both the slotted and circular-shaped coils. The noise figure values of two coils were investigated via the numerical calculation of the quality factors. Fat simulated phantoms to mimic overweight rats were included in the analysis with weights ranging from 300 to 900 g. The noise figures were 1.2 dB for the slotted coil and 2.4 dB for the circular coil when loaded with 600 g of simulated phantom. A slotted surface coil with eight circular slots and a circular coil with similar dimensions were built and operated in the transceiver mode, and their performances were experimentally compared. The imaging tests in phantoms demonstrated that the slotted surface coil has a deeper RF-sensitivity and better field uniformity than the single-loop RF-coil. High quality images of two overweight Zucker rats were acquired simultaneously with the slotted surface coil using standard spin-echo pulse sequences. Experimental results showed that the slotted surface coil outperformed the circular coil for imaging considerably overweight rats. Thus, the slotted surface coil can be a good tool for MRI experiments in rats on a human whole-body 4 T scanner.

  8. A multi-slot surface coil for MRI of dual-rat imaging at 4T

    SciTech Connect

    Solis, S.E.; Tomasi, D.; Solis, S.E.; Wang, R.; Tomasi, D.; Rodriguez, A.O.

    2011-07-01

    A slotted surface coil inspired by the hole-and-slot cavity magnetron was developed for magnetic resonance imaging of obese rats at 4 T. Full-wave analysis of the magnetic field was carried out at 170 MHz for both the slotted and circular-shaped coils. The noise figure values of two coils were investigated via the numerical calculation of the quality factors. Fat simulated phantoms to mimic overweight rats were included in the analysis with weights ranging from 300 to 900 g. The noise figures were 1.2 dB for the slotted coil and 2.4 dB for the circular coil when loaded with 600 g of simulated phantom. A slotted surface coil with eight circular slots and a circular coil with similar dimensions were built and operated in the transceiver mode, and their performances were experimentally compared. The imaging tests in phantoms demonstrated that the slotted surface coil has a deeper RF-sensitivity and better field uniformity than the single-loop RF-coil. High quality images of two overweight Zucker rats were acquired simultaneously with the slotted surface coil using standard spin-echo pulse sequences. Experimental results showed that the slotted surface coil outperformed the circular coil for imaging considerably overweight rats. Thus, the slotted surface coil can be a good tool for MRI experiments in rats on a human whole-body 4 T scanner.

  9. Development of promyelocytic leukemia zinc finger-expressing innate CD4 T cells requires stronger T-cell receptor signals than conventional CD4 T cells.

    PubMed

    Qiao, Yu; Zhu, Lingqiao; Sofi, Hanief; Lapinski, Philip E; Horai, Reiko; Mueller, Kristen; Stritesky, Gretta L; He, Xi; Teh, Hung-Sia; Wiest, David L; Kappes, Dietmar J; King, Philip D; Hogquist, Kristin A; Schwartzberg, Pamela L; Sant'Angelo, Derek B; Chang, Cheong-Hee

    2012-10-02

    MHC class II-expressing thymocytes and thymic epithelial cells can mediate CD4 T-cell selection resulting in functionally distinct thymocyte-selected CD4 (T-CD4) and epithelial-selected CD4 (E-CD4) T cells, respectively. However, little is known about how T-cell receptor (TCR) signaling influences the development of these two CD4 T-cell subsets. To study TCR signaling for T-CD4 T-cell development, we used a GFP reporter system of Nur77 in which GFP intensity directly correlates with TCR signaling strength. T-CD4 T cells expressed higher levels of GFP than E-CD4 T cells, suggesting that T-CD4 T cells received stronger TCR signaling than E-CD4 T cells during selection. Elimination of Ras GTPase-activating protein enhanced E-CD4 but decreased T-CD4 T-cell selection efficiency, suggesting a shift to negative selection. Conversely, the absence of IL-2-inducible T-cell kinase that causes poor E-CD4 T-cell selection due to insufficient TCR signaling improved T-CD4 T-cell generation, consistent with rescue from negative selection. Strong TCR signaling during T-CD4 T-cell development correlates with the expression of the transcription factor promyelocytic leukemia zinc finger protein. However, although modulation of the signaling strength affected the efficiency of T-CD4 T-cell development during positive and negative selection, the signaling strength is not as important for the effector function of T-CD4 T cells. These findings indicate that innate T-CD4 T cells, together with invariant natural killer T cells and γδ T cells, receive strong TCR signals during their development and that signaling requirements for the development and the effector functions are distinct.

  10. Functional aortic stiffness: role of CD4(+) T lymphocytes.

    PubMed

    Majeed, Beenish A; Eberson, Lance S; Tawinwung, Supannikar; Larmonier, Nicolas; Secomb, Timothy W; Larson, Douglas F

    2015-01-01

    The immune system is suggested to be essential in vascular remodeling and stiffening. To study the dependence upon lymphocytes in vascular stiffening, we compared an angiotensin II-model of vascular stiffening in normal C57BL/6J mice with lymphocyte-deficient RAG 1(-/-) mice and additionally characterized the component of vascular stiffness due to vasoconstriction vs. vascular remodeling. Chronic angiotensin II increased aortic pulse wave velocity, effective wall stiffness, and effective Young's modulus in C57BL/6J mice by three-fold but caused no change in the RAG 1(-/-) mice. These functional measurements were supported by aortic morphometric analysis. Adoptive transfer of CD4(+) T helper lymphocytes restored the angiotensin II-mediated aortic stiffening in the RAG 1(-/-) mice. In order to account for the hydraulic vs. material effects of angiotensin II on pulse wave velocity, subcutaneous osmotic pumps were removed after 21 days of angiotensin II-infusion in the WT mice to achieve normotensive values. The pulse wave velocity (PWV) decreased from three- to two-fold above baseline values up to 7 days following pump removal. This study supports the pivotal role of the CD4(+) T-lymphocytes in angiotensin II-mediated vascular stiffening and that angiotensin II-mediated aortic stiffening is due to the additive effect of active vascular smooth muscle vasoconstriction and vascular remodeling.

  11. The variation of protons, alpha particles, and the magnetic field across the bow shock of Comet Halley

    NASA Technical Reports Server (NTRS)

    Neugebauer, M.; Goldstein, B. E.; Goldstein, R.; Neubauer, F. M.; Balsiger, H.; Fuselier, S. A.

    1987-01-01

    Data from the Ion Mass Spectrometer and the magnetometer on the Giotto spacecraft are used to examine the structure of the inbound crossing of the Comet Halley bow shock on March 13, 1986. It is found that the velocity decrease, the field strength increase, and the heating of picked up cometary protons occurred over a broad region corresponding to several heavy-ion gyroradii. The solar-wind protons and alphas, on the other hand, were compressed and heated at a narrow structure on the leading edge of the broad shock region.

  12. The variation of protons, alpha particles, and the magnetic field across the bow shock of Comet Halley

    NASA Technical Reports Server (NTRS)

    Neugebauer, M.; Goldstein, B. E.; Goldstein, R.; Neubauer, F. M.; Balsiger, H.; Fuselier, S. A.

    1987-01-01

    Data from the Ion Mass Spectrometer and the magnetometer on the Giotto spacecraft are used to examine the structure of the inbound crossing of the Comet Halley bow shock on March 13, 1986. It is found that the velocity decrease, the field strength increase, and the heating of picked up cometary protons occurred over a broad region corresponding to several heavy-ion gyroradii. The solar-wind protons and alphas, on the other hand, were compressed and heated at a narrow structure on the leading edge of the broad shock region.

  13. Ex vivo analysis of human memory CD4 T cells specific for hepatitis C virus using MHC class II tetramers.

    PubMed

    Day, Cheryl L; Seth, Nilufer P; Lucas, Michaela; Appel, Heiner; Gauthier, Laurent; Lauer, Georg M; Robbins, Gregory K; Szczepiorkowski, Zbigniew M; Casson, Deborah R; Chung, Raymond T; Bell, Shannon; Harcourt, Gillian; Walker, Bruce D; Klenerman, Paul; Wucherpfennig, Kai W

    2003-09-01

    Containment of hepatitis C virus (HCV) and other chronic human viral infections is associated with persistence of virus-specific CD4 T cells, but ex vivo characterization of circulating CD4 T cells has not been achieved. To further define the phenotype and function of these cells, we developed a novel approach for the generation of tetrameric forms of MHC class II/peptide complexes that is based on the cellular peptide-exchange mechanism. HLA-DR molecules were expressed as precursors with a covalently linked CLIP peptide, which could be efficiently exchanged with viral peptides following linker cleavage. In subjects who spontaneously resolved HCV viremia, but not in those with chronic progressive infection, HCV tetramer-labeled cells could be isolated by magnetic bead capture despite very low frequencies (1:1,200 to 1:111,000) among circulating CD4 T cells. These T cells expressed a set of surface receptors (CCR7+CD45RA-CD27+) indicative of a surveillance function for secondary lymphoid structures and had undergone significant in vivo selection since they utilized a restricted Vbeta repertoire. These studies demonstrate a relationship between clinical outcome and the presence of circulating CD4 T cells directed against this virus. Moreover, they show that rare populations of memory CD4 T cells can be studied ex vivo in human diseases.

  14. Non-invasive tracking of CD4+ T cells with a paramagnetic and fluorescent nanoparticle in brain ischemia

    PubMed Central

    Jin, Wei-Na; Yang, Xiaoxia; Li, Zhiguo; Li, Minshu; Shi, Samuel Xiang-Yu; Wood, Kristofer; Fu, Ying; Han, Wei; Xu, Yun; Shi, Fu-Dong; Liu, Qiang

    2015-01-01

    Recent studies have demonstrated that lymphocytes play a key role in ischemic brain injury. However, there is still a lack of viable approaches to non-invasively track infiltrating lymphocytes and reveal their key spatiotemporal events in the inflamed central nervous system (CNS). Here we describe an in vivo imaging approach for sequential monitoring of brain-infiltrating CD4+ T cells in experimental ischemic stroke. We show that magnetic resonance imaging (MRI) or Xenogen imaging combined with labeling of SPIO-Molday ION Rhodamine-B (MIRB) can be used to monitor the dynamics of CD4+ T cells in a passive transfer model. MIRB-labeled CD4+ T cells can be longitudinally visualized in the mouse brain and peripheral organs such as the spleen and liver after cerebral ischemia. Immunostaining of tissue sections showed similar kinetics of MIRB-labeled CD4+ T cells when compared with in vivo observations. Our results demonstrated the use of MIRB coupled with in vivo imaging as a valid method to track CD4+ T cells in ischemic brain injury. This approach will facilitate future investigations to identify the dynamics and key spatiotemporal events for brain-infiltrating lymphocytes in CNS inflammatory diseases. PMID:26661207

  15. Sensitivity and Source of Amine Proton EXchange (APEX) and Amide Proton Transfer (APT) MRI in Cerebral Ischemia

    PubMed Central

    Zong, Xiaopeng; Wang, Ping; Kim, Seong-Gi; Jin, Tao

    2013-01-01

    Purpose Amide proton transfer (APT) and amine-water proton exchange (APEX) can be viable to map pH-decreasing ischemic regions. However, their exact contributions are unclear. Methods We measured APEX- and APT-weighted magnetization transfer ratio asymmetry (denoted as APEXw and APTw), ADC, T2 and T1 images, and localized proton spectra in rats with permanent middle cerebral artery occlusion at 9.4 T. Phantoms and theoretical studies were also performed. Results Within one hour post-occlusion, APEXw and APTw maps showed hyperintensity (3.1% of M0) and hypointensity (−1.8%), respectively, in regions with decreased ADC. Ischemia increased lactate and gamma aminobutyric acid (GABA) concentrations, but decreased glutamate and taurine concentrations. Over time, the APEXw contrast decreased with glutamate, taurine and creatine, while the APTw contrast and lactate level were similar. Phantom and theoretical studies suggest that the source of APEXw signal is mainly from proteins at normal pH, while at decreased pH, GABA and glutamate contributions increase, inducing the positive APEXw contrast in ischemic regions. The APTw contrast is sensitive to lactate concentration and pH, but contaminated from contributions of the faster amine-water proton exchange processes. Conclusion Positive APEXw contrast is more sensitive to ischemia than negative APTw contrast. They may provide complementary tissue metabolic information. PMID:23401310

  16. Nuclear magnetic relaxation studies of water in frozen biological tissues. Cross-relaxation effects between protein and bound water protons

    NASA Astrophysics Data System (ADS)

    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.

  17. Priming of CD4+ T cells and development of CD4+ T cell memory; lessons for malaria.

    PubMed

    Stephens, R; Langhorne, J

    2006-01-01

    CD4 T cells play a central role in the immune response to malaria. They are required to help B cells produce the antibody that is essential for parasite clearance. They also produce cytokines that amplify the phagocytic and parasitocidal response of the innate immune system, as well as dampening this response later on to limit immunopathology. Therefore, understanding the mechanisms by which T helper cells are activated and the requirements for development of specific, and effective, T cell memory and immunity is essential in the quest for a malaria vaccine. In this paper on the CD4 session of the Immunology of Malaria Infections meeting, we summarize discussions of CD4 cell priming and memory in malaria and in vaccination and outline critical future lines of investigation. B. Stockinger and M.K. Jenkins proposed cutting edge experimental systems to study basic T cell biology in malaria. Critical parameters in T cell activation include the cell types involved, the route of infection and the timing and location and cell types involved in antigen presentation. A new generation of vaccines that induce CD4 T cell activation and memory are being developed with new adjuvants. Studies of T cell memory focus on differentiation and factors involved in maintenance of antigen specific T cells and control of the size of that population. To improve detection of T cell memory in the field, efforts will have to be made to distinguish antigen-specific responses from cytokine driven responses.

  18. Control of inflammatory heart disease by CD4+ T cells.

    PubMed

    Barin, Jobert G; Čiháková, Daniela

    2013-05-01

    This review focuses on autoimmune myocarditis and its sequela, inflammatory dilated cardiomyopathy (DCMI), and the inflammatory and immune mechanisms underlying the pathogenesis of these diseases. Several mouse models of myocarditis and DCMI have improved our knowledge of the pathogenesis of these diseases, informing more general problems of cardiac remodeling and heart failure. CD4(+) T cells are critical in driving the pathogenesis of myocarditis. We discuss in detail the role of T helper cell subtypes in the pathogenesis of myocarditis, the biology of T cell-derived effector cytokines, and the participation of other leukocytic effectors in mediating disease pathophysiology. We discuss interactions between these subsets in both suppressive and collaborative fashions. These findings indicate that cardiac inflammatory disease, and autoimmunity in general, may be more diverse in divergent effector mechanisms than has previously been appreciated.

  19. Plasticity of Human CD4 T Cell Subsets

    PubMed Central

    Geginat, Jens; Paroni, Moira; Maglie, Stefano; Alfen, Johanna Sophie; Kastirr, Ilko; Gruarin, Paola; De Simone, Marco; Pagani, Massimiliano; Abrignani, Sergio

    2014-01-01

    Human beings are exposed to a variety of different pathogens, which induce tailored immune responses and consequently generate highly diverse populations of pathogen-specific T cells. CD4+ T cells have a central role in adaptive immunity, since they provide essential help for both cytotoxic T cell- and antibody-mediated responses. In addition, CD4+ regulatory T cells are required to maintain self-tolerance and to inhibit immune responses that could damage the host. Initially, two subsets of CD4+ helper T cells were identified that secrete characteristic effector cytokines and mediate responses against different types of pathogens, i.e., IFN-γ secreting Th1 cells that fight intracellular pathogens, and IL-4 producing Th2 cells that target extracellular parasites. It is now well established that this dichotomy is insufficient to describe the complexity of CD4+ T cell differentiation, and in particular the human CD4 compartment contains a myriad of T cell subsets with characteristic capacities to produce cytokines and to home to involved tissues. Moreover, it has become increasingly clear that these T cell subsets are not all terminally differentiated cells, but that the majority is plastic and that in particular central memory T cells can acquire different properties and functions in secondary immune responses. In addition, there is compelling evidence that helper T cells can acquire regulatory functions upon chronic stimulation in inflamed tissues. The plasticity of antigen-experienced human T cell subsets is highly relevant for translational medicine, since it opens new perspectives for immune-modulatory therapies for chronic infections, autoimmune diseases, and cancer. PMID:25566245

  20. Experimental characterization of the hydride 1H shielding tensors for HIrX2(PR3)2 and HRhCl2(PR3)2: extremely shielded hydride protons with unusually large magnetic shielding anisotropies.

    PubMed

    Garbacz, Piotr; Terskikh, Victor V; Ferguson, Michael J; Bernard, Guy M; Kędziorek, Mariusz; Wasylishen, Roderick E

    2014-02-20

    The hydride proton magnetic shielding tensors for a series of iridium(III) and rhodium(III) complexes are determined. Although it has long been known that hydridic protons for transition-metal hydrides are often extremely shielded, this is the first experimental determination of the shielding tensors for such complexes. Isolating the (1)H NMR signal for a hydride proton requires careful experimental strategies because the spectra are generally dominated by ligand (1)H signals. We show that this can be accomplished for complexes containing as many as 66 ligand protons by substituting the latter with deuterium and by using hyperbolic secant pulses to selectively irradiate the hydride proton signal. We also demonstrate that the quality of the results is improved by performing experiments at the highest practical magnetic field (21.14 T for the work presented here). The hydride protons for iridium hydride complexes HIrX2(PR3)2 (X = Cl, Br, or I; R = isopropyl, cyclohexyl) are highly shielded with isotropic chemical shifts of approximately -50 ppm and are also highly anisotropic, with spans (=δ11 - δ33) ranging from 85.1 to 110.7 ppm. The hydridic protons for related rhodium complexes HRhCl2(PR3)2 also have unusual magnetic shielding properties with chemical shifts and spans of approximately -32 and 85 ppm, respectively. Relativistic density functional theory computations were performed to determine the orientation of the principal components of the hydride proton shielding tensors and to provide insights into the origin of these highly anisotropic shielding tensors. The results of our computations agree well with experiment, and our conclusions concerning the importance of relativistic effects support those recently reported by Kaupp and co-workers.

  1. The Schwarzschild Proton

    SciTech Connect

    Haramein, Nassim

    2010-11-24

    We review our model of a proton that obeys the Schwarzschild condition. We find that only a very small percentage ({approx}10{sup -39}%) of the vacuum fluctuations available within a proton volume need be cohered and converted to mass-energy in order for the proton to meet the Schwarzschild condition. This proportion is equivalent to that between gravitation and the strong force where gravitation is thought to be {approx}10{sup -38} to 10{sup -40} weaker than the strong force. Gravitational attraction between two contiguous Schwarzschild protons can accommodate both nucleon and quark confinement. We calculate that two contiguous Schwarzschild protons would rotate at c and have a period of 10{sup -23} s and a frequency of 10{sup 22} Hz which is characteristic of the strong force interaction time and a close approximation of the gamma emission typically associated with nuclear decay. We include a scaling law and find that the Schwarzschild proton data point lies near the least squares trend line for organized matter. Using a semi-classical model, we find that a proton charge orbiting at a proton radius at c generates a good approximation to the measured anomalous magnetic moment.

  2. Relationships between LDH-A, lactate, and metastases in 4T1 breast tumors.

    PubMed

    Rizwan, Asif; Serganova, Inna; Khanin, Raya; Karabeber, Hazem; Ni, Xiaohui; Thakur, Sunitha; Zakian, Kristen L; Blasberg, Ronald; Koutcher, Jason A

    2013-09-15

    To investigate the relationship between lactate dehydrogenase A (LDH-A) expression, lactate concentration, cell metabolism, and metastases in murine 4T1 breast tumors. Inhibition of LDH-A expression and protein levels were achieved in a metastatic breast cancer cell line (4T1) using short hairpin RNA (shRNA) technology. The relationship between tumor LDH-A protein levels and lactate concentration (measured by magnetic resonance spectroscopic imaging, MRSI) and metastases was assessed. LDH-A knockdown cells (KD9) showed a significant reduction in LDH-A protein and LDH activity, less acid production, decreased transwell migration and invasion, lower proliferation, reduced glucose consumption and glycolysis, and increase in oxygen consumption, reactive oxygen species (ROS), and cellular ATP levels, compared with control (NC) cells cultured in 25 mmol/L glucose. In vivo studies showed lower lactate levels in KD9, KD5, and KD317 tumors than in NC or 4T1 wild-type tumors (P < 0.01), and a linear relationship between tumor LDH-A protein expression and lactate concentration. Metastases were delayed and primary tumor growth rate decreased. We show for the first time that LDH-A knockdown inhibited the formation of metastases, and was accompanied by in vivo changes in tumor cell metabolism. Lactate MRSI can be used as a surrogate to monitor targeted inhibition of LDH-A in a preclinical setting and provides a noninvasive imaging strategy to monitor LDH-A-targeted therapy. This imaging strategy can be translated to the clinic to identify and monitor patients who are at high risk of developing metastatic disease. ©2013 AACR.

  3. Relationships between LDH-A, Lactate and Metastases in 4T1 Breast Tumors

    PubMed Central

    Rizwan, Asif; Serganova, Inna; Khanin, Raya; Karabeber, Hazem; Ni, Xiaohui; Thakur, Sunitha; Zakian, Kristen L.; Blasberg, Ronald; Koutcher, Jason A.

    2013-01-01

    Purpose To investigate the relationship between LDH-A expression, lactate concentration, cell metabolism and metastases in murine 4T1 breast tumors. Experimental Design Inhibition of LDH-A expression and protein levels were achieved in a metastatic breast cancer cell line (4T1) using shRNA technology. The relationship between tumor LDH-A protein levels and lactate concentration (measured by magnetic resonance spectroscopic imaging-MRSI) and metastases was assessed. Results LDH-A knockdown cells (KD9) showed a significant reduction in LDH-A protein and LDH activity, less acid production, decreased transwell migration and invasion, lower proliferation, reduced glucose utilization and glycolysis and increase in oxygen consumption, ROS and cellular ATP levels, compared to control (NC) cells cultured in 25 mM glucose. In vivo studies showed lower lactate levels in KD9, KD5, KD317 tumors than in NC or 4T1 wild-type tumors (p<0.01), and a linear relationship between tumor LDH-A protein expression and lactate concentration. Metastases were delayed and primary tumor growth rate decreased. Conclusions We show for the first time that LDH-A knockdown inhibited the formation of metastases, and was accompanied by in vivo changes in tumor cell metabolism. Lactate MRSI can be used as a surrogate to monitor targeted inhibition of LDH-A in a pre-clinical setting and provides a non-invasive imaging strategy to monitor LDH-A targeted therapy. This imaging strategy can be translated to the clinic to identify and monitor patients who are at high risk of developing metastatic disease. PMID:23833310

  4. Proton nuclear magnetic resonance characterization of the aromatic residues in the variant-3 neurotoxin from Centruroides sculpturatus Ewing

    SciTech Connect

    Krishna, N.R.; Nettesheim, D.G.; Klevit, R.E.; Drobny, G.; Watt, D.D.; Bugg, C.E. )

    1989-02-21

    The amino acid sequence for the variant-3 (CsE-v3) toxin from the venom of the scorpion Centruroides sculpturatus Ewing contains eight aromatic residues. By use of 2D NMR spectroscopic methods, the resonances from the individual protons (NH, C{sup alpha}H, C{sup beta}H{prime}, H{double prime}, and the ring) for each of the individual aromatic residues have been completely assigned. The spatial arrangement of the aromatic ring systems with respect to each other has been qualitatively analyzed by 2D-NOESY techniques. The results show that Trp-47, Tyr-4, and Tyr-42 are in close spatial proximity to each other. The NOESY contacts and the ring current induced shifts in the resonances of the individual protons of Tyr-4 and Trp-47 suggest that the aromatic ring planes of these residues are in an orthogonal arrangement. A comparison with the published crystal structure suggests that there is a minor rearrangement of the aromatic rings in the solution phase. No 2D-NOESY contacts involving Phe-44 and Tyr-14 to any other aromatic ring protons have been observed. The pH dependence of the aromatic ring proton chemical shifts has also been studied. These results suggest that the Tyr-58 phenolic group is experiencing a hydrogen-bonding interaction with a positively charged group, while Tyr-4, -14, -38, and -40 are experiencing through-space interactions with proximal negatively charged groups. These studies define the microenvironment of the aromatic residues in the variant-3 neurotoxin in aqueous solution.

  5. Detection of nuclear overhauser effects between degenerate amide proton resonances by heteronuclear three-dimensional nuclear magnetic resonance spectroscopy

    SciTech Connect

    Ikura, Mitsuhiko; Bax, A.; Clore, G.M.; Gronenborn, A.M. )

    1990-11-21

    The key to protein structure determination by NMR lies in the identification of as many {sup 1}H-{sup 1}H nuclear Overhauser effects (NOEs) as possible in order to obtain a large set of approximate interproton distance restraints. With the advent of a range of heteronuclear three-dimensional (3D) NMR experiments, it has now become possible to obtain complete {sup 1}H, {sup 15}N, and {sup 13}C assignments and to determine the 3D structures of proteins in the 15-25-kDa molecular weight range. Despite these advances, it has remained impossible to observe NOEs between protons with degenerate chemical shifts. Such interactions occur repeatedly, both among aliphatic or aromatic protons and between sequential amide protons in helical proteins. Here the authors describe a 3D heteronuclear experiment that allows the observation of these NOEs and demonstrate its applicability for calmodulin, a protein of 148 residues and molecular weight 16.7 kDa.

  6. Ultrasensitive detection and phenotyping of CD4+ T cells with optimized HLA class II tetramer staining.

    PubMed

    Scriba, Thomas J; Purbhoo, Marco; Day, Cheryl L; Robinson, Nicola; Fidler, Sarah; Fox, Julie; Weber, Jonathan N; Klenerman, Paul; Sewell, Andrew K; Phillips, Rodney E

    2005-11-15

    HLA class I tetramers have revolutionized the study of Ag-specific CD8+ T cell responses. Technical problems and the rarity of Ag-specific CD4+ Th cells have not allowed the potential of HLA class II tetramers to be fully realized. Here, we optimize HLA class II tetramer staining methods through the use of a comprehensive panel of HIV-, influenza-, CMV-, and tetanus toxoid-specific tetramers. We find rapid and efficient staining of DR1- and DR4-restricted CD4+ cell lines and clones and show that TCR internalization is not a requirement for immunological staining. We combine tetramer staining with magnetic bead enrichment to detect rare Ag-specific CD4+ T cells with frequencies as low as 1 in 250,000 (0.0004% of CD4+ cells) in human PBLs analyzed directly ex vivo. This ultrasensitive detection allowed phenotypic analysis of rare CD4+ T lymphocytes that had experienced diverse exposure to Ag during the course of viral infections. These cells would not be detectable with normal flow-cytometric techniques.

  7. Effect of N-acetylaspartic acid on the diffusion coefficient of water: a proton magnetic resonance phantom method for measurement of osmolyte-obligated water.

    PubMed

    Baslow, Morris H; Guilfoyle, David N

    2002-12-15

    N-acetyl-L-aspartic acid (NAA) is an amino acid present in the vertebrate brain that is synthesized and stored primarily in neurons, although it cannot be hydrolyzed in these cells. Nonetheless, neuronal NAA is dynamic and turns over more than once each day by cycling, via extracellular fluids (ECF), between neurons and catabolic compartments in oligodendrocytes. One important role of the NAA intercompartmental cycle appears to be osmoregulatory, and in this role it may be the primary mechanism for the removal of metabolic water, against a water gradient, from myelinated neurons. However, the number of water molecules that might be cotransported to ECF per NAA molecule released is as yet unclear. In this investigation, using a proton nuclear magnetic resonance method and diffusion measurements at two magnetic field strengths on water and NAA phantoms in vitro, the effect of NAA on the diffusion coefficient of water has been measured, and a ratio (K) of obligated water molecules per molecule of NAA has been determined. For NAA measured at 100mM and 3 Tesla K=24 and at 7 Tesla K=14. Based on these results, apparent K(NAA) varies inversely with field strength, and with a computed field strength factor of 2.55mmol water/unit Tesla, K(NAA) in the absence of any applied magnetic field strength would be 32.

  8. Correction of proton resonance frequency shift MR-thermometry errors caused by heat-induced magnetic susceptibility changes during high intensity focused ultrasound ablations in tissues containing fat.

    PubMed

    Baron, Paul; Deckers, Roel; de Greef, Martijn; Merckel, Laura G; Bakker, Chris J G; Bouwman, Job G; Bleys, Ronald L A W; van den Bosch, Maurice A A J; Bartels, Lambertus W

    2014-12-01

    In this study, we aim to demonstrate the sensitivity of proton resonance frequency shift (PRFS) -based thermometry to heat-induced magnetic susceptibility changes and to present and evaluate a model-based correction procedure. To demonstrate the expected temperature effect, field disturbances during high intensity focused ultrasound sonications were monitored in breast fat samples with a three-dimensional (3D) gradient echo sequence. To evaluate the correction procedure, the interface of tissue-mimicking ethylene glycol gel and fat was sonicated. During sonication, the temperature was monitored with a 2D dual flip angle multi-echo gradient echo sequence, allowing for PRFS-based relative and referenced temperature measurements in the gel and T1 -based temperature measurements in fat. The PRFS-based measurement in the gel was corrected by minimizing the discrepancy between the observed 2D temperature profile and the profile predicted by a 3D thermal model. The HIFU sonications of breast fat resulted in a magnetic field disturbance which completely disappeared after cooling. For the correction method, the 5th to 95th percentile interval of the PRFS-thermometry error in the gel decreased from 3.8°C before correction to 2.0-2.3°C after correction. This study has shown the effects of magnetic susceptibility changes induced by heating of breast fatty tissue samples. The resultant errors can be reduced by the use of a model-based correction procedure. © 2013 Wiley Periodicals, Inc.

  9. Regulation of allergic airway inflammation by adoptive transfer of CD4(+) T cells preferentially producing IL-10.

    PubMed

    Matsuda, Masaya; Doi, Kana; Tsutsumi, Tatsuya; Fujii, Shinya; Kishima, Maki; Nishimura, Kazuma; Kuroda, Ikue; Tanahashi, Yu; Yuasa, Rino; Kinjo, Toshihiko; Kuramoto, Nobuyuki; Mizutani, Nobuaki; Nabe, Takeshi

    2017-10-05

    Anti-inflammatory pharmacotherapy for asthma has mainly depended on the inhalation of glucocorticoids, which non-specifically suppress immune responses. If the anti-inflammatory cytokine interleukin (IL)-10 can be induced by a specific antigen, asthmatic airway inflammation could be suppressed when individuals are exposed to the antigen. The purpose of this study was to develop cellular immunotherapeutics for atopic diseases using IL-10-producing CD4(+) T cells. Spleen cells isolated from ovalbumin (OVA)-sensitized mice were cultured with the antigen, OVA and growth factors, IL-21, IL-27 and TGF-β for 7 days. After the 7-day culture, the CD4(+) T cells were purified using a murine CD4 magnetic beads system. When the induced CD4(+) T cells were stimulated by OVA in the presence of antigen-presenting cells, IL-10 was preferentially produced in vitro. When CD4(+) T cells were adoptively transferred to OVA-sensitized mice followed by intratracheal OVA challenges, IL-10 was preferentially produced in the serum and bronchoalveolar lavage fluid in vivo. IL-10 production coincided with the inhibition of eosinophilic airway inflammation and epithelial mucus plugging. Most of the IL-10-producing CD4(+) T cells were negative for Foxp3 and GATA-3, transcription factors of naturally occurring regulatory T cells and Th2 cells, respectively, but double positive for LAG-3 and CD49b, surface markers of inducible regulatory T cells, Tr1 cells. Collectively, most of the induced IL-10-producing CD4(+) T cells could be Tr1 cells, which respond to the antigen to produce IL-10, and effectively suppressed allergic airway inflammation. The induced Tr1 cells may be useful for antigen-specific cellular immunotherapy for atopic diseases. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Aryl hydrocarbon receptor controls regulatory CD4+ T cell function.

    PubMed

    Pot, Caroline

    2012-05-31

    The ligand activated transcription factor aryl hydrocarbon receptor (AhR) has been studied for many decades in toxicology as the ligand for the environmental contaminant dioxin. However, AhR has recently emerged as a critical physiological regulator of immune responses affecting both innate and adaptive systems, and several AhR ligands with different pharmacological profiles have recently been studied. The current review discusses new insights into the role of AhR signalling and AhR ligands on the regulation of the immune system, with a focus on regulatory T cells which maintain immune tolerance. Notably, AhR is expressed and modulates the development of two induced regulatory CD4+ T cell subsets, the forkhead box P3-positive (Foxp3+) regulatory T cells (iTreg) and the IL-10-secreting type 1 regulatory T (T(R)1) cells, through different signalling pathways. We will finally discuss how AhR ligands could be exploited to alleviate human autoimmune diseases. Clearly, drugs targeted against AhR should promote the development of new strategies to fight against autoimmune diseases.

  11. Magnetization transfer contrast-suppressed imaging of amide proton transfer and relayed nuclear overhauser enhancement chemical exchange saturation transfer effects in the human brain at 7T.

    PubMed

    Xu, Xiang; Yadav, Nirbhay N; Zeng, Haifeng; Jones, Craig K; Zhou, Jinyuan; van Zijl, Peter C M; Xu, Jiadi

    2016-01-01

    To use the variable delay multipulse (VDMP) chemical exchange saturation transfer (CEST) approach to obtain clean amide proton transfer (APT) and relayed Nuclear Overhauser enhancement (rNOE) CEST images in the human brain by suppressing the conventional magnetization transfer contrast (MTC) and reducing the direct water saturation contribution. The VDMP CEST scheme consists of a train of RF pulses with a specific mixing time. The CEST signal with respect to the mixing time shows distinguishable characteristics for protons with different exchange rates. Exchange rate filtered CEST images are generated by subtracting images acquired at two mixing times at which the MTC signals are equal, while the APT and rNOE-CEST signals differ. Because the subtraction is performed at the same frequency offset for each voxel and the CEST signals are broad, no B0 correction is needed. MTC-suppressed APT and rNOE-CEST images of human brain were obtained using the VDMP method. The APT-CEST data show hyperintensity in gray matter versus white matter, whereas the rNOE-CEST images show negligible contrast between gray and white matter. The VDMP approach provides a simple and rapid way of recording MTC-suppressed APT-CEST and rNOE-CEST images without the need for B0 field correction. © 2015 Wiley Periodicals, Inc.

  12. N-acetylaspartate levels of left frontal cortex are associated with verbal intelligence in women but not in men: a proton magnetic resonance spectroscopy study.

    PubMed

    Pfleiderer, B; Ohrmann, P; Suslow, T; Wolgast, M; Gerlach, A L; Heindel, W; Michael, N

    2004-01-01

    The left frontal cortex plays an important role in executive function and complex language processing inclusive of spoken language. The purpose of this work was to assess metabolite levels in the left and right prefrontal cortex and left anterior cingulum by proton magnetic resonance spectroscopy and relate results to verbal intelligence (Wechsler Adult Intelligence Scale revised) in a sample of college-educated healthy volunteers (dorsolateral prefrontal cortex [DLPFC]: n=52, 23 females, and left anterior cingulum: n=62, 22 females; age range: 20-75 years). In women only, N-acetylaspartate in the DLPFC and in the left anterior cingulate cortex was positively correlated with vocabulary scores. Our data support the hypothesis of existing gender differences regarding the involvement of the left frontal cortex in verbal processing as reflected in different correlations of specific metabolites with verbal scores.

  13. In-Vivo Proton Magnetic Resonance Spectroscopy of 2-Hydroxyglutarate in Isocitrate Dehydrogenase-Mutated Gliomas: A Technical Review for Neuroradiologists

    PubMed Central

    Kim, Sungjin; Lee, Hyeong Hun; Heo, Hwon

    2016-01-01

    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. PMID:27587950

  14. g factor of the J/sup. pi. / = 25/2/sup +/ isomer in /sup 205/Tl and the anomalous orbital magnetism of the proton

    SciTech Connect

    Maier, K.H.; Becker, J.A.; Carlson, J.B.; Lanier, R.G.; Mann, L.G.; Struble, G.L.; Nail, T.; Sheline, R.K.; Stoeffl, W.; Ussery, L.

    1982-02-15

    The nuclear gyromagnetic ratio of the 3291-keV J/sup ..pi../ = 25/2/sup +/ /sup 205/Tl level has been measured with use of ..gamma..-ray perturbed angular distribution techniques with the result g = 0.544 +- 0.008. The state was populated with the reaction /sup 204/Hg(t,2n)/sup 205/Tl. With use of the known quantities g(/sup 206/Pb 7/sup -/; E/sub x/ = 2200 keV) and g(/sup 209/Bi 9/2/sup +/; E/sub x/ = 0 keV) the proton orbital magnetic g factor for the 1h orbital was deduced to be g/sub 1/ = 1.115 +- 0.02. This result has been corrected for wave-function admixtures and core polarization effects.

  15. Limited CD4+ T cell proliferation leads to preservation of CD4+ T cell counts in SIV-infected sooty mangabeys.

    PubMed

    Chan, Ming Liang; Petravic, Janka; Ortiz, Alexandra M; Engram, Jessica; Paiardini, Mirko; Cromer, Deborah; Silvestri, Guido; Davenport, Miles P

    2010-12-22

    Human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) infections result in chronic virus replication and progressive depletion of CD4+ T cells, leading to immunodeficiency and death. In contrast, 'natural hosts' of SIV experience persistent infection with high virus replication but no severe CD4+ T cell depletion, and remain AIDS-free. One important difference between pathogenic and non-pathogenic infections is the level of activation and proliferation of CD4+ T cells. We analysed the relationship between CD4+ T cell number and proliferation in HIV, pathogenic SIV in macaques, and non-pathogenic SIV in sooty mangabeys (SMs) and mandrills. We found that CD4+ T cell proliferation was negatively correlated with CD4+ T cell number, suggesting that animals respond to the loss of CD4+ T cells by increasing the proliferation of remaining cells. However, the level of proliferation seen in pathogenic infections (SIV in rhesus macaques and HIV) was much greater than in non-pathogenic infections (SMs and mandrills). We then used a modelling approach to understand how the host proliferative response to CD4+ T cell depletion may impact the outcome of infection. This modelling demonstrates that the rapid proliferation of CD4+ T cells in humans and macaques associated with low CD4+ T cell levels can act to 'fuel the fire' of infection by providing more proliferating cells for infection. Natural host species, on the other hand, have limited proliferation of CD4+ T cells at low CD4+ T cell levels, which allows them to restrict the number of proliferating cells susceptible to infection.

  16. 7T Proton Magnetic Resonance Spectroscopy of Gamma-Aminobutyric Acid, Glutamate, and Glutamine Reveals Altered Concentrations in Patients With Schizophrenia and Healthy Siblings.

    PubMed

    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.

  17. Influence of the magnetic field on the density distribution of solar wind protons and cometary ions in the shock layer ahead of cometary ionospheres

    NASA Astrophysics Data System (ADS)

    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

  18. Proton Therapy

    MedlinePlus

    ... Proton Therapy Alternative & Integrative Medicine Clinical Trials GBM AGILE TTFields – Optune™ Brain Tumor Treatment Locations Treatment Side ... Proton Therapy Alternative & Integrative Medicine Clinical Trials GBM AGILE TTFields – Optune™ Brain Tumor Treatment Locations Treatment Side ...

  19. Lorentz contracted proton

    NASA Astrophysics Data System (ADS)

    Bedoya Fierro, D.; Kelkar, N. G.; Nowakowski, M.

    2015-09-01

    The proton charge and magnetization density distributions can be related to the well known Sachs electromagnetic form factors G E, M ( q 2) through Fourier transforms, only in the Breit frame. The Breit frame however moves with relativistic velocities in the Lab and a Lorentz boost must be applied before extracting the static properties of the proton from the corresponding densities. Apart from this, the Fourier transform relating the densities and form factors is inherently a non-relativistic expression. We show that the relativistic corrections to it can be obtained by extending the standard Breit equation to higher orders in its 1 /c 2 expansion. We find that the inclusion of the above corrections reduces the size of the proton as determined from electron proton scattering data by about 4%.

  20. 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.

    PubMed

    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.

  1. Enantioselective Protonation

    PubMed Central

    Mohr, Justin T.; Hong, Allen Y.; Stoltz, Brian M.

    2010-01-01

    Enantioselective protonation is a common process in biosynthetic sequences. The decarboxylase and esterase enzymes that effect this valuable transformation are able to control both the steric environment around the proton acceptor (typically an enolate) and the proton donor (typically a thiol). Recently, several chemical methods to achieve enantioselective protonation have been developed by exploiting various means of enantiocontrol in different mechanisms. These laboratory transformations have proven useful for the preparation of a number of valuable organic compounds. PMID:20428461

  2. Conditions That Induce Tolerance in Mature CD4+ T Cells

    PubMed Central

    Lanoue, Astrid; Bona, Constantin; von Boehmer, Harald; Sarukhan, Adelaida

    1997-01-01

    Establishment of antigen-specific tolerance among mature T cells has been a long debated, yet poorly understood issue. In this study we have used transgenic mice bearing a class II–restricted TCR specific for the hemmagglutinin of the influenza virus in order to test the behavior of CD4+ T cells upon exposure to antigen in different forms and doses. We first studied the fate of T cells expressing the transgenic TCR (6.5) in double transgenic mice where HA was expressed as a self antigen by hemapoietic cells. In these mice, we found some mature T cells in periphery that had escaped thymic deletion and that showed signs of activation but which were anergic. Mature CD4+6.5+ cells that were transferred into antigen-containing recipients went through an initial phase of expansion after which most cells were deleted and those remaining became unresponsive, as previously described for CD8+ cells. Inducing tolerance in CD4+6.5+ cells in situ in single transgenic mice proved a difficult task: classical protocols using single doses of soluble or deaggregated antigen as well as feeding antigen all failed to induce antigen-specific unresponsiveness. It was only after decreasing cell numbers by CD4 antibody treatment and by repeatedly reintroducing antigen thereafter that unresponsiveness of 6.5+ cells was achieved and maintained. In no case could we observe the appearance of antigen-specific T cells with a Th2 cytokine profile among the remaining cells and therefore conclude that deletion and anergy represent the major mechanisms of tolerance in our studies. PMID:9053441

  3. Traditional Korean medicine (SCRT) modulate Th1/Th2 specific cytokine production in mice CD4+ T cell.

    PubMed

    Ko, Eunjung; Rho, Samwoong; Lee, Eui-Joon; Seo, Young-Ho; Cho, Chongwoon; Lee, Yongwon; Min, Byung-Il; Shin, Min-Kyu; Hong, Moo-Chang; Bae, Hyunsu

    2004-05-01

    Traditional Korea medicine, So-Cheong-Ryong-Tang (SCRT) also called as Xiao-qing-long-tang or Sho-seiru-to, contains eight species of medicinal plants and has been used for treating allergic diseases, such as allergic rhinitis and asthma, for hundreds of years in Asian countries. CD4+ T cells were highly purified by using magnetic bead from splenocytes of BALB/c mice. SCRT treatment slightly decreased the expression of cell surface protein CD69 on CD4+ T cell in the flow cytometry analysis. In RT-PCR analysis, SCRT increases the expression of IL-2 and IL2R-alpha mRNA, and decreases the expression of IL-4 mRNA, which is an important cytokine of Th2 cell development. On the other hand, SCRT treatment increases IFN-gamma expression, which is one of the key cytokines for Th1 cell development. Present study implies that SCRT can correct Th2 dominant condition directly affecting to the CD4+ T cell without significantly depressing general T cell activities. These results also suggest that the effect on CD4+ T cell may be the one of key pharmacological effect point for treating IgE medicated allergic asthma by SCRT.

  4. Cardiovascular Magnetic Resonance Imaging

    NASA Astrophysics Data System (ADS)

    Pelc, Norbert

    2000-03-01

    Cardiovascular diseases are a major source of morbidity and mortality in the United States. Early detection of disease can often be used to improved outcomes, either through direct interventions (e.g. surgical corrections) or by causing the patient to modify his or her behavior (e.g. smoking cessation or dietary changes). Ideally, the detection process should be noninvasive (i.e. it should not be associated with significant risk). Magnetic Resonance Imaging (MRI) refers to the formation of images by localizing NMR signals, typically from protons in the body. As in other applications of NMR, a homogeneous static magnetic field ( ~0.5 to 4 T) is used to create ``longitudinal" magnetization. A magnetic field rotating at the Larmor frequency (proportional to the static field) excites spins, converting longitudinal magnetization to ``transverse" magnetization and generating a signal. Localization is performed using pulsed gradients in the static field. MRI can produce images of 2-D slices, 3-D volumes, time-resolved images of pseudo-periodic phenomena such as heart function, and even real-time imaging. It is also possible to acquire spatially localized NMR spectra. MRI has a number of advantages, but perhaps the most fundamental is the richness of the contrast mechanisms. Tissues can be differentiated by differences in proton density, NMR properties, and even flow or motion. We also have the ability to introduce substances that alter NMR signals. These contrast agents can be used to enhance vascular structures and measure perfusion. Cardiovascular MRI allows the reliable diagnosis of important conditions. It is possible to image the blood vessel tree, quantitate flow and perfusion, and image cardiac contraction. Fundamentally, the power of MRI as a diagnostic tool stems from the richness of the contrast mechanisms and the flexibility in control of imaging parameters.

  5. Initial in vivo Rodent Sodium and Proton MR Imaging at 21.1 T

    PubMed Central

    Schepkin, Victor D.; Brey, William W.; Gor’kov, Peter L.; Grant, Samuel C.

    2009-01-01

    The first in vivo sodium and proton MR images and localized spectra of rodents were attained using the wide bore (105 mm) high resolution 21.1 T magnet, built and operated at the National High Magnetic Field Laboratory (Tallahassee, FL). Head images of normal mice (C57BL/6J) and Fisher rats (~ 250 g) were acquired with custom designed RF probes at frequencies of 237/900 MHz for sodium and proton, respectively. Sodium MRI resolutions of ~0.125 μL for mouse and rat heads were achieved by using a 3D back-projection pulse sequence. A gain in SNR of ~ 3 for sodium and of ~ 2 times for proton were found relative to corresponding MR images acquired at 9.4 T. 3D FLASH proton mouse images (50×50×50 μm3) were acquired in 90 min and corresponding rat images (100×100×100 μm3) within a total time of 120 min. Both in vivo large rodent MR imaging and localized spectroscopy at the extremely high field of 21.1 T are feasible and demonstrate improved resolution and sensitivity valuable for structural and functional brain analysis. PMID:20045599

  6. CD4+ T-cell deficiency in HIV patients responding to antiretroviral therapy is associated with increased expression of interferon-stimulated genes in CD4+ T cells.

    PubMed

    Fernandez, Sonia; Tanaskovic, Sara; Helbig, Karla; Rajasuriar, Reena; Kramski, Marit; Murray, John M; Beard, Michael; Purcell, Damian; Lewin, Sharon R; Price, Patricia; French, Martyn A

    2011-12-15

    Most patients with human immunodeficiency virus (HIV) who remain CD4(+) T-cell deficient on antiretroviral therapy (ART) exhibit marked immune activation. As CD4(+) T-cell activation may be mediated by microbial translocation or interferon-alpha (IFN-α), we examined these factors in HIV patients with good or poor CD4(+) T-cell recovery on long-term ART. Messenger RNA levels for 3 interferon-stimulated genes were increased in CD4(+) T cells of patients with poor CD4(+) T-cell recovery, whereas levels in patients with good recovery did not differ from those in healthy controls. Poor CD4(+) T-cell recovery was also associated with CD4(+) T-cell expression of markers of activation, senescence, and apoptosis, and with increased serum levels of the lipopolysaccharide receptor and soluble CD14, but these were not significantly correlated with expression of the interferon-stimulated genes. Therefore, CD4(+) T-cell recovery may be adversely affected by the effects of IFN-α, which may be amenable to therapeutic intervention.

  7. 26 CFR 1.469-4T - Definition of activity (temporary).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 6 2012-04-01 2012-04-01 false Definition of activity (temporary). 1.469-4T Section 1.469-4T Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Taxable Year for Which Deductions Taken § 1.469-4T Definition of activity (temporary). (a) Overview—(1)...

  8. 17 CFR 240.11a1-4(T) - Bond transactions on national securities exchanges.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Bond transactions on national securities exchanges. 240.11a1-4(T) Section 240.11a1-4(T) Commodity and Securities Exchanges SECURITIES AND....11a1-4(T) Bond transactions on national securities exchanges. A transaction in a bond, note,...

  9. Proton nuclear magnetic resonance studies of hydrogen diffusion and electron tunneling in Ni-Nb-Zr-H glassy alloys

    SciTech Connect

    Niki, Haruo; Okuda, Hiroyuki; Oshiro, Morihito; Yogi, Mamoru; Seki, Ichiro; Fukuhara, Mikio

    2012-06-15

    Using the Fourier transform of the echo envelope, the proton line shapes, spin-lattice relaxation time, and spin-spin relaxation time have been measured in a (Ni{sub 0.36}Nb{sub 0.24}Zr{sub 0.40}){sub 90}H{sub 10} glassy alloy at 1.83 T ({approx}78 MHz) and at temperatures between 1.8 and 300 K. First, the spectral line width decreases abruptly between 1.8 and 2.1 K. Next, it remains almost constant at 13 kHz up to {approx}150 K. Finally, the line width decreases as the temperature increases from {approx}150 to 300 K. The initial decrease in the spectral line width is ascribed to the distribution of the external field, which is caused by the penetration of vortices in the superconducting state. The subsequent leveling off in the spectral line width is ascribed to the dipole-dipole interaction between protons when hydrogen atoms are trapped into vacancies among the Zr-centered icosahedral Zr{sub 5}Ni{sub 5}Nb{sub 3} clusters. The final decrease in the spectral line width is ascribed to the motional narrowing of the width that is caused by the movement of hydrogen atoms. The temperature dependences of the spin-lattice and spin-spin relaxation time showed that at temperature above 150 K and the activation energy of 8.7 kJ/mol allowed the hydrogen atoms to migrate among the clusters. The distance between the hydrogen atoms is estimated to be 2.75 A. Hydrogen occupancies among clusters in the (Ni{sub 0.36}Nb{sub 0.24}Zr{sub 0.40}){sub 90}H{sub 10} glassy alloy play an important role in the diffusion behavior and in the electronic properties of this alloy.

  10. Cerebellar Volume and Proton Magnetic Resonance Spectroscopy at Term, and Neurodevelopment at 2 Years of Age in Preterm Infants

    ERIC Educational Resources Information Center

    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]).…

  11. Cerebellar Volume and Proton Magnetic Resonance Spectroscopy at Term, and Neurodevelopment at 2 Years of Age in Preterm Infants

    ERIC Educational Resources Information Center

    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]).…

  12. Determining the mechanism of cusp proton aurora

    PubMed Central

    Xiao, Fuliang; Zong, Qiugang; Su, Zhenpeng; Yang, Chang; He, Zhaoguo; Wang, Yongfu; Gao, Zhonglei

    2013-01-01

    Earth's cusp proton aurora occurs near the prenoon and is primarily produced by the precipitation of solar energetic (2–10 keV) protons. Cusp auroral precipitation provides a direct source of energy for the high-latitude dayside upper atmosphere, contributing to chemical composition change and global climate variability. Previous studies have indicated that magnetic reconnection allows solar energetic protons to cross the magnetopause and enter the cusp region, producing cusp auroral precipitation. However, energetic protons are easily trapped in the cusp region due to a minimum magnetic field existing there. Hence, the mechanism of cusp proton aurora has remained a significant challenge for tens of years. Based on the satellite data and calculations of diffusion equation, we demonstrate that EMIC waves can yield the trapped proton scattering that causes cusp proton aurora. This moves forward a step toward identifying the generation mechanism of cusp proton aurora. PMID:23575366

  13. Determining the mechanism of cusp proton aurora.

    PubMed

    Xiao, Fuliang; Zong, Qiugang; Su, Zhenpeng; Yang, Chang; He, Zhaoguo; Wang, Yongfu; Gao, Zhonglei

    2013-01-01

    Earth's cusp proton aurora occurs near the prenoon and is primarily produced by the precipitation of solar energetic (2-10 keV) protons. Cusp auroral precipitation provides a direct source of energy for the high-latitude dayside upper atmosphere, contributing to chemical composition change and global climate variability. Previous studies have indicated that magnetic reconnection allows solar energetic protons to cross the magnetopause and enter the cusp region, producing cusp auroral precipitation. However, energetic protons are easily trapped in the cusp region due to a minimum magnetic field existing there. Hence, the mechanism of cusp proton aurora has remained a significant challenge for tens of years. Based on the satellite data and calculations of diffusion equation, we demonstrate that EMIC waves can yield the trapped proton scattering that causes cusp proton aurora. This moves forward a step toward identifying the generation mechanism of cusp proton aurora.

  14. Rosenbluth Award: First observations of Rayleigh-Taylor-induced magnetic fields in laser-produced plasmas using x rays and protons

    NASA Astrophysics Data System (ADS)

    Manuel, Mario

    2014-10-01

    Recent experiments [Manuel, PRL 108 (2012)] demonstrated the existence of self-generated B-fields from the Rayleigh-Taylor (RT) instability in laser-produced plasmas, as originally predicted by Mima et al. [Mima PRL 41 (1978)]. Misaligned density and temperature gradients caused by RT growth in ablatively driven targets generate B-fields in the plasma through the Biermann battery source. X-ray and proton radiography diagnosed areal-density and B-field perturbations in laser-irradiated targets with seeded sinusoidal surface perturbations. Inferred B-field strengths indicated ratios of thermal to magnetic pressures (β) near the ablation surface of 104-105, suggesting no magnetic effects on ablative RT during the linear growth phase. However, the magnitude of this self-generated field increases with the perturbation height [Srinivasan, PRL 108 (2012)] and can affect morphology in the nonlinear regime. The detailed structure of highly nonlinear RT spikes is important to understand the inner wall expansion of hohlraums in indirect-drive inertial fusion and in multiple astrophysical systems, including the explosion phase of core-collapse supernovae and formation of planetary nebulae. Numerical calculations investigating the magnetic effects on nonlinear RT-spike evolution under conditions similar to previous measurements will be covered and implications discussed. Support for this work was provided by NASA through Einstein Postdoctoral Fellowship grant number PF3-140111 awarded by the Chandra X-ray Center, which is operated by the Astrophysical Observatory for NASA under Contract NAS8-03060. This work is funded by the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasma under Grant Number DE-NA0001840. Previous work described here was supported in part by NLUF (DE-NA0000877), FSC/UR (415023-G), DoE (DE-FG52-09NA29553), LLE (414090-G), and LLNL (B580243).

  15. Magnetic resonance safety and compatibility of tantalum markers used in proton beam therapy for intraocular tumors: A 7.0 Tesla study.

    PubMed

    Oberacker, Eva; Paul, Katharina; Huelnhagen, Till; Oezerdem, Celal; Winter, Lukas; Pohlmann, Andreas; Boehmert, Laura; Stachs, Oliver; Heufelder, Jens; Weber, Andreas; Rehak, Matus; Seibel, Ira; Niendorf, Thoralf

    2017-10-01

    Proton radiation therapy (PRT) is a standard treatment of uveal melanoma. PRT patients undergo implantation of ocular tantalum markers (OTMs) for treatment planning. Ultra-high-field MRI is a promising technique for 3D tumor visualization and PRT planning. This work examines MR safety and compatibility of OTMs at 7.0 Tesla. MR safety assessment included deflection angle measurements (DAMs), electromagnetic field (EMF) simulations for specific absorption rate (SAR) estimation, and temperature simulations for examining radiofrequency heating using a bow-tie dipole antenna for transmission. MR compatibility was assessed by susceptibility artifacts in agarose, ex vivo pig eyes, and in an ex vivo tumor eye using gradient echo and fast spin-echo imaging. DAM (α < 1 °) demonstrated no risk attributed to magnetically induced OTM deflection. EMF simulations showed that an OTM can be approximated by a disk, demonstrated the need for averaging masses of mave  = 0.01 g to accommodate the OTM, and provided SAR0.01g,maximum  = 2.64 W/kg (Pin  = 1W) in OTM presence. A transfer function was derived, enabling SAR0.01g estimation for individual patient scenarios without the OTM being integrated. Thermal simulations revealed minor OTM-related temperature increase (δT < 15 mK). Susceptibility artifact size (<8 mm) and location suggest no restrictions for MRI of the nervus opticus. OTMs are not a per se contraindication for MRI. Magn Reson Med 78:1533-1546, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  16. Severe TSH Elevation and Pituitary Enlargement After Changing Thyroid Replacement to Compounded T4/T3 Therapy.

    PubMed

    Pappy, Adlai L; Oyesiku, Nelson; Ioachimescu, Adriana

    2016-01-01

    We present the first case of iatrogenic hypothyroidism as a result of compounded thyroid hormone (T4/T3) therapy. The thyroid replacement was changed from 175 µg levothyroxine (LT4) to 57/13.5 µg compounded T4/T3 daily in order to improve the T3 level, despite normal thyroid-stimulating hormone (TSH). This resulted in clinical manifestations of hypothyroidism and high TSH level (150 µIU/mL). Six months later, the patient was referred to our clinic for abnormal pituitary magnetic resonance imaging. On reinitiating a physiologic dose of LT4, clinical and biochemical abnormalities resolved and the pituitary gland size decreased. Our case emphasizes the importance of using TSH level to gauge dose adjustments in primary hypothyroidism. Also, it underscores the current American Thyroid Association recommendation against routine use of compounded thyroid hormone therapy.

  17. Severe TSH Elevation and Pituitary Enlargement After Changing Thyroid Replacement to Compounded T4/T3 Therapy

    PubMed Central

    Pappy, Adlai L.; Oyesiku, Nelson; Ioachimescu, Adriana

    2016-01-01

    We p