Magnetic Particle Imaging for High Temporal Resolution Assessment of Aneurysm Hemodynamics.

Directory of Open Access Journals (Sweden)

Jan Sedlacik

Full Text Available The purpose of this work was to demonstrate the capability of magnetic particle imaging (MPI to assess the hemodynamics in a realistic 3D aneurysm model obtained by additive manufacturing. MPI was compared with magnetic resonance imaging (MRI and dynamic digital subtraction angiography (DSA.The aneurysm model was of saccular morphology (7 mm dome height, 5 mm cross-section, 3-4 mm neck, 3.5 mm parent artery diameter and connected to a peristaltic pump delivering a physiological flow (250 mL/min and pulsation rate (70/min. High-resolution (4 h long 4D phase contrast flow quantification (4D pc-fq MRI was used to directly assess the hemodynamics of the model. Dynamic MPI, MRI, and DSA were performed with contrast agent injections (3 mL volume in 3 s through a proximally placed catheter.4D pc-fq measurements showed distinct pulsatile flow velocities (20-80 cm/s as well as lower flow velocities and a vortex inside the aneurysm. All three dynamic methods (MPI, MRI, and DSA also showed a clear pulsation pattern as well as delayed contrast agent dynamics within the aneurysm, which is most likely caused by the vortex within the aneurysm. Due to the high temporal resolution of MPI and DSA, it was possible to track the contrast agent bolus through the model and to estimate the average flow velocity (about 60 cm/s, which is in accordance with the 4D pc-fq measurements.The ionizing radiation free, 4D high resolution MPI method is a very promising tool for imaging and characterization of hemodynamics in human. It carries the possibility of overcoming certain disadvantages of other modalities like considerably lower temporal resolution of dynamic MRI and limited 2D characteristics of DSA. Furthermore, additive manufacturing is the key for translating powerful pre-clinical techniques into the clinic.

ANL high resolution injector

International Nuclear Information System (INIS)

Minehara, E.; Kutschera, W.; Hartog, P.D.; Billquist, P.

1985-01-01

The ANL (Argonne National Laboratory) high-resolution injector has been installed to obtain higher mass resolution and higher preacceleration, and to utilize effectively the full mass range of ATLAS (Argonne Tandem Linac Accelerator System). Preliminary results of the first beam test are reported briefly. The design and performance, in particular a high-mass-resolution magnet with aberration compensation, are discussed. 7 refs., 5 figs., 2 tabs

Magnetic Microcalorimeter (MMC) Gamma Detectors with Ultra-High Energy Resolution

Energy Technology Data Exchange (ETDEWEB)

Friedrich, Stephen [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2018-01-19

The goal of this LCP is to develop ultra-high resolution gamma detectors based on magnetic microcalorimeters (MMCs) for accurate non-destructive analysis (NDA) of nuclear materials. For highest energy resolution, we will introduce erbium-doped silver (Ag:Er) as a novel sensor material, and implement several geometry and design changes to improve the signal-to-noise ratio. The detector sensitivity will be increased by developing arrays of 32 Ag:Er pixels read out by 16 SQUID preamplifiers, and by developing a cryogenic Compton veto to reduce the spectral background. Since best MMC performance requires detector operation at ~10 mK, we will purchase a dilution refrigerator with a base temperature <10 mK and adapt it for MMC operation. The detector performance will be tested with radioactive sources of interest to the safeguards community.

Localization and Retrieval of an Eyelid Metallic Foreign Body With an Oscillating Magnet and High-Resolution Ultrasonography.

Science.gov (United States)

Yoo, Sylvia H; Rootman, Dan B; Goh, Alice; Savar, Aaron; Goldberg, Robert A

2016-01-01

A patient was found to have a metallic foreign body in the left anterior orbit on CT imaging, but the foreign body was not evident on clinical examination. On high-resolution ultrasonography, an object was identified in the left upper eyelid; however, the typical shadow with metallic foreign bodies was not seen. A high-power oscillating magnet was then applied to the eyelid, which revealed a subcutaneous metallic foreign body in the left upper eyelid. When used in conjunction, the high-resolution ultrasound and oscillating magnet successfully localized and facilitated retrieval of the metallic foreign body from the left upper eyelid.

Los Alamos Meson Physics Facility high-resolution-spectrometer dipole magnets: a summary report

International Nuclear Information System (INIS)

Kozlowski, T.; Madland, D.G.; Rolfe, R.; Smith, W.E.; Spencer, J.E.; Tanaka, N.; Thiessen, H.A.; Varghese, P.; Wilkerson, L.C.

1982-12-01

This report explains the design, fabrication, measurement, optimization, and installation of two 122 metric ton electromagnets for the High Resolution Proton Spectrometer at the Los Alamos Meson Physics Facility. These two magnets are the principal components of the proton spectrometer, which has an energy resolution of less than or equal to 10 - 4 FWHM. Many technical problems occurred during fabrication, measurement, and optimization, and the majority have been successfully solved. We hope that this report will help others planning similar projects

High-resolution magnetic resonance spectroscopy using a solid-state spin sensor

Science.gov (United States)

Glenn, David R.; Bucher, Dominik B.; Lee, Junghyun; Lukin, Mikhail D.; Park, Hongkun; Walsworth, Ronald L.

2018-03-01

Quantum systems that consist of solid-state electronic spins can be sensitive detectors of nuclear magnetic resonance (NMR) signals, particularly from very small samples. For example, nitrogen–vacancy centres in diamond have been used to record NMR signals from nanometre-scale samples, with sensitivity sufficient to detect the magnetic field produced by a single protein. However, the best reported spectral resolution for NMR of molecules using nitrogen–vacancy centres is about 100 hertz. This is insufficient to resolve the key spectral identifiers of molecular structure that are critical to NMR applications in chemistry, structural biology and materials research, such as scalar couplings (which require a resolution of less than ten hertz) and small chemical shifts (which require a resolution of around one part per million of the nuclear Larmor frequency). Conventional, inductively detected NMR can provide the necessary high spectral resolution, but its limited sensitivity typically requires millimetre-scale samples, precluding applications that involve smaller samples, such as picolitre-volume chemical analysis or correlated optical and NMR microscopy. Here we demonstrate a measurement technique that uses a solid-state spin sensor (a magnetometer) consisting of an ensemble of nitrogen–vacancy centres in combination with a narrowband synchronized readout protocol to obtain NMR spectral resolution of about one hertz. We use this technique to observe NMR scalar couplings in a micrometre-scale sample volume of approximately ten picolitres. We also use the ensemble of nitrogen–vacancy centres to apply NMR to thermally polarized nuclear spins and resolve chemical-shift spectra from small molecules. Our technique enables analytical NMR spectroscopy at the scale of single cells.

High resolution studies of the effects of magnetic fields on chemical reactions

OpenAIRE

Hamilton, C. A.; Hewitt, J. P.; McLauchlan, Keith A.; Steiner, Ulrich

1988-01-01

A simple and inexpensive experiment is described which detects magnetic field effects on chemical reactions with high signal-to-noise ratio and high resolution. It consists in applying a small modulation field to the sample, whilst the main field it experiences is varied, with optical detection at the modulation frequency. It consequently measures the derivative of the normal MARY spectrum. It is shown by theoretical analysis that when using this method it is better to monitor reaction interm...

Theory of high-resolution tunneling spin transport on a magnetic skyrmion

Science.gov (United States)

Palotás, Krisztián; Rózsa, Levente; Szunyogh, László

2018-05-01

Tunneling spin transport characteristics of a magnetic skyrmion are described theoretically in magnetic scanning tunneling microscopy (STM). The spin-polarized charge current in STM (SP-STM) and tunneling spin transport vector quantities, the longitudinal spin current and the spin transfer torque, are calculated in high spatial resolution within the same theoretical framework. A connection between the conventional charge current SP-STM image contrasts and the magnitudes of the spin transport vectors is demonstrated that enables the estimation of tunneling spin transport properties based on experimentally measured SP-STM images. A considerable tunability of the spin transport vectors by the involved spin polarizations is also highlighted. These possibilities and the combined theory of tunneling charge and vector spin transport pave the way for gaining deep insight into electric-current-induced tunneling spin transport properties in SP-STM and to the related dynamics of complex magnetic textures at surfaces.

High-resolution X-ray television and high-resolution video recorders

International Nuclear Information System (INIS)

Haendle, J.; Horbaschek, H.; Alexandrescu, M.

1977-01-01

The improved transmission properties of the high-resolution X-ray television chain described here make it possible to transmit more information per television image. The resolution in the fluoroscopic image, which is visually determined, depends on the dose rate and the inertia of the television pick-up tube. This connection is discussed. In the last few years, video recorders have been increasingly used in X-ray diagnostics. The video recorder is a further quality-limiting element in X-ray television. The development of function patterns of high-resolution magnetic video recorders shows that this quality drop may be largely overcome. The influence of electrical band width and number of lines on the resolution in the X-ray television image stored is explained in more detail. (orig.) [de

Structure of high-resolution NMR spectra

CERN Document Server

Corio, PL

2012-01-01

Structure of High-Resolution NMR Spectra provides the principles, theories, and mathematical and physical concepts of high-resolution nuclear magnetic resonance spectra.The book presents the elementary theory of magnetic resonance; the quantum mechanical theory of angular momentum; the general theory of steady state spectra; and multiple quantum transitions, double resonance and spin echo experiments.Physicists, chemists, and researchers will find the book a valuable reference text.

High-resolution mechanical imaging of glioblastoma by multifrequency magnetic resonance elastography.

Directory of Open Access Journals (Sweden)

Kaspar-Josche Streitberger

Full Text Available OBJECTIVE: To generate high-resolution maps of the viscoelastic properties of human brain parenchyma for presurgical quantitative assessment in glioblastoma (GB. METHODS: Twenty-two GB patients underwent routine presurgical work-up supplemented by additional multifrequency magnetic resonance elastography. Two three-dimensional viscoelastic parameter maps, magnitude |G*|, and phase angle φ of the complex shear modulus were reconstructed by inversion of full wave field data in 2-mm isotropic resolution at seven harmonic drive frequencies ranging from 30 to 60 Hz. RESULTS: Mechanical brain maps confirmed that GB are composed of stiff and soft compartments, resulting in high intratumor heterogeneity. GB could be easily differentiated from healthy reference tissue by their reduced viscous behavior quantified by φ (0.37±0.08 vs. 0.58±0.07. |G*|, which in solids more relates to the material's stiffness, was significantly reduced in GB with a mean value of 1.32±0.26 kPa compared to 1.54±0.27 kPa in healthy tissue (P = 0.001. However, some GB (5 of 22 showed increased stiffness. CONCLUSION: GB are generally less viscous and softer than healthy brain parenchyma. Unrelated to the morphology-based contrast of standard magnetic resonance imaging, elastography provides an entirely new neuroradiological marker and contrast related to the biomechanical properties of tumors.

High-resolution imaging of magnetic fields using scanning superconducting quantum interference device (SQUID) microscopy

Science.gov (United States)

Fong de Los Santos, Luis E.

Development of a scanning superconducting quantum interference device (SQUID) microscope system with interchangeable sensor configurations for imaging magnetic fields of room-temperature (RT) samples with sub-millimeter resolution. The low-critical-temperature (Tc) niobium-based monolithic SQUID sensor is mounted in the tip of a sapphire rod and thermally anchored to the cryostat helium reservoir. A 25 mum sapphire window separates the vacuum space from the RT sample. A positioning mechanism allows adjusting the sample-to-sensor spacing from the top of the Dewar. I have achieved a sensor-to-sample spacing of 100 mum, which could be maintained for periods of up to 4 weeks. Different SQUID sensor configurations are necessary to achieve the best combination of spatial resolution and field sensitivity for a given magnetic source. For imaging thin sections of geological samples, I used a custom-designed monolithic low-Tc niobium bare SQUID sensor, with an effective diameter of 80 mum, and achieved a field sensitivity of 1.5 pT/Hz1/2 and a magnetic moment sensitivity of 5.4 x 10-18 Am2/Hz1/2 at a sensor-to-sample spacing of 100 mum in the white noise region for frequencies above 100 Hz. Imaging action currents in cardiac tissue requires higher field sensitivity, which can only be achieved by compromising spatial resolution. I developed a monolithic low-Tc niobium multiloop SQUID sensor, with sensor sizes ranging from 250 mum to 1 mm, and achieved sensitivities of 480 - 180 fT/Hz1/2 in the white noise region for frequencies above 100 Hz, respectively. For all sensor configurations, the spatial resolution was comparable to the effective diameter and limited by the sensor-to-sample spacing. Spatial registration allowed us to compare high-resolution images of magnetic fields associated with action currents and optical recordings of transmembrane potentials to study the bidomain nature of cardiac tissue or to match petrography to magnetic field maps in thin sections of

Tablet disintegration studied by high-resolution real-time magnetic resonance imaging.

Science.gov (United States)

Quodbach, Julian; Moussavi, Amir; Tammer, Roland; Frahm, Jens; Kleinebudde, Peter

2014-01-01

The present work employs recent advances in high-resolution real-time magnetic resonance imaging (MRI) to investigate the disintegration process of tablets containing disintegrants. A temporal resolution of 75 ms and a spatial resolution of 80 × 80 µm with a section thickness of only 600 µm were achieved. The histograms of MRI videos were quantitatively analyzed with MATLAB. The mechanisms of action of six commercially available disintegrants, the influence of relative tablet density, and the impact of disintegrant concentration were examined. Crospovidone seems to be the only disintegrant acting by a shape memory effect, whereas the others mainly swell. A higher relative density of tablets containing croscarmellose sodium leads to a more even distribution of water within the tablet matrix but hardly impacts the disintegration kinetics. Increasing the polacrilin potassium disintegrant concentration leads to a quicker and more thorough disintegration process. Real-time MRI emerges as valuable tool to visualize and investigate the process of tablet disintegration.

Transcranial magnetic stimulation of mouse brain using high-resolution anatomical models

Science.gov (United States)

Crowther, L. J.; Hadimani, R. L.; Kanthasamy, A. G.; Jiles, D. C.

2014-05-01

Transcranial magnetic stimulation (TMS) offers the possibility of non-invasive treatment of brain disorders in humans. Studies on animals can allow rapid progress of the research including exploring a variety of different treatment conditions. Numerical calculations using animal models are needed to help design suitable TMS coils for use in animal experiments, in particular, to estimate the electric field induced in animal brains. In this paper, we have implemented a high-resolution anatomical MRI-derived mouse model consisting of 50 tissue types to accurately calculate induced electric field in the mouse brain. Magnetic field measurements have been performed on the surface of the coil and compared with the calculations in order to validate the calculated magnetic and induced electric fields in the brain. Results show how the induced electric field is distributed in a mouse brain and allow investigation of how this could be improved for TMS studies using mice. The findings have important implications in further preclinical development of TMS for treatment of human diseases.

Metallic magnetic calorimeters for high resolution X-ray spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Krantz, M.; Hengstler, D.; Geist, J.; Schoetz, C.; Hassel, K.; Hendricks, S.; Keller, M.; Kempf, S.; Gastaldo, L.; Fleischmann, A.; Enss, C. [Heidelberg Univ. (Germany). KIP

2015-07-01

We develop microfabricated, energy dispersive particle detector arrays based on metallic magnetic calorimeters (MMCs) for high resolution X-ray spectroscopy to challenge bound-state QED calculations. Our MMCs are operated at about T=30 mK and use a paramagnetic temperature sensor, read-out by a SQUID, to measure the energy deposited by single X-ray photons. We discuss the physics of MMCs, the detector performance and the cryogenic setups for two different detector arrays. We present their microfabrication layouts with focus on challenges like the heatsinking of each pixel of the detector and the overhanging absorbers. The maXs-20 detector is a linear 1x8-pixel array with excellent linearity in its designated energy range up to 20 keV and unsurpassed energy resolution of 1.6 eV for 6 keV x-rays. MaXs-20 operated in a highly portable pulse tube cooled ADR setup has already been used at the EBIT facilities of the MPI-K for new reference measurements of V-like and Ti-like tungsten. The maXs-30 detector currently in development is a 8x8-pixel 2d-array with an active detection area of 16 mm{sup 2} and is designed to detect X-rays up to 50 keV with a designated energy resolution below 5 eV. MaXs-30 will be operated in a cryogen free 3He/4He-dilution refrigerator at the tip of a 40 cm long cold finger at T=20 mK.

Real-time and quantitative isotropic spatial resolution susceptibility imaging for magnetic nanoparticles

Science.gov (United States)

Pi, Shiqiang; Liu, Wenzhong; Jiang, Tao

2018-03-01

The magnetic transparency of biological tissue allows the magnetic nanoparticle (MNP) to be a promising functional sensor and contrast agent. The complex susceptibility of MNPs, strongly influenced by particle concentration, excitation magnetic field and their surrounding microenvironment, provides significant implications for biomedical applications. Therefore, magnetic susceptibility imaging of high spatial resolution will give more detailed information during the process of MNP-aided diagnosis and therapy. In this study, we present a novel spatial magnetic susceptibility extraction method for MNPs under a gradient magnetic field, a low-frequency drive magnetic field, and a weak strength high-frequency magnetic field. Based on this novel method, a magnetic particle susceptibility imaging (MPSI) of millimeter-level spatial resolution (<3 mm) was achieved using our homemade imaging system. Corroborated by the experimental results, the MPSI shows real-time (1 s per frame acquisition) and quantitative abilities, and isotropic high resolution.

First high-resolution near-seafloor survey of magnetic anomalies of the South China Sea

Science.gov (United States)

Lin, J.; Xu, X.; Li, C.; Sun, Z.; Zhu, J.; Zhou, Z.; Qiu, N.

2013-12-01

We successfully conducted the first high-resolution near-seafloor magnetic survey of the Central, Southwest, and Northern Central Basins of the South China Sea (SCS) during two cruises on board Chinese R/V HaiYangLiuHao in October-November 2012 and March-April 2013, respectively. Measurements of magnetic field were made along four long survey lines, including (1) a NW-SE across-isochron profile transecting the Southwest Basin and covering all ages of the oceanic crust (Line CD); (2) a N-S across-isochron profile transecting the Central Basin (Line AB); and (3) two sub-parallel NE-SW across-isochron profiles transecting the Northern Central Basin of the SCS (Lines D and E). A three-axis magnetometer was mounted on a deep-tow vehicle, flying within 0.6 km above the seafloor. The position of the tow vehicle was provided by an ultra-short baseline navigation system along Lines D and E, while was estimated using shipboard GPS along Lines AB and CD. To investigate crustal magnetization, we first removed the International Geomagnetic Reference Field (IGRF) of 2010 from the measured magnetic data, and then downward continued the resultant magnetic field data to a horizontal plane at a water depth of 4.5 km to correct for variation due to the fishing depth of the deep-tow vehicle. Finally, we calculated magnetic anomalies at various water depths after reduction-to-the-pole corrections. We also constructed polarity reversal block (PRB) models of crustal magnetization by matching peaks and troughs of the observed magnetic field anomaly. Our analysis yielded the following results: (1) The near-bottom magnetic anomaly showed peak-to-trough amplitudes of more than 2,500 nT, which are several times of the anomaly amplitudes at the sea surface, illustrating that deep-tow measurements acquired much higher spatial resolutions. (2) The deep-tow data revealed several distinctive magnetic anomalies with wavelengths of 5-15 km and amplitudes of several hundred nT. These short

Development of AMS high resolution injector system

International Nuclear Information System (INIS)

Bao Yiwen; Guan Xialing; Hu Yueming

2008-01-01

The Beijing HI-13 tandem accelerator AMS high resolution injector system was developed. The high resolution energy achromatic system consists of an electrostatic analyzer and a magnetic analyzer, which mass resolution can reach 600 and transmission is better than 80%. (authors)

Robust high-resolution quantification of time signals encoded by in vivo magnetic resonance spectroscopy

Science.gov (United States)

Belkić, Dževad; Belkić, Karen

2018-01-01

This paper on molecular imaging emphasizes improving specificity of magnetic resonance spectroscopy (MRS) for early cancer diagnostics by high-resolution data analysis. Sensitivity of magnetic resonance imaging (MRI) is excellent, but specificity is insufficient. Specificity is improved with MRS by going beyond morphology to assess the biochemical content of tissue. This is contingent upon accurate data quantification of diagnostically relevant biomolecules. Quantification is spectral analysis which reconstructs chemical shifts, amplitudes and relaxation times of metabolites. Chemical shifts inform on electronic shielding of resonating nuclei bound to different molecular compounds. Oscillation amplitudes in time signals retrieve the abundance of MR sensitive nuclei whose number is proportional to metabolite concentrations. Transverse relaxation times, the reciprocal of decay probabilities of resonances, arise from spin-spin coupling and reflect local field inhomogeneities. In MRS single voxels are used. For volumetric coverage, multi-voxels are employed within a hybrid of MRS and MRI called magnetic resonance spectroscopic imaging (MRSI). Common to MRS and MRSI is encoding of time signals and subsequent spectral analysis. Encoded data do not provide direct clinical information. Spectral analysis of time signals can yield the quantitative information, of which metabolite concentrations are the most clinically important. This information is equivocal with standard data analysis through the non-parametric, low-resolution fast Fourier transform and post-processing via fitting. By applying the fast Padé transform (FPT) with high-resolution, noise suppression and exact quantification via quantum mechanical signal processing, advances are made, presented herein, focusing on four areas of critical public health importance: brain, prostate, breast and ovarian cancers.

Characterizing the Motion of Solar Magnetic Bright Points at High Resolution

Science.gov (United States)

Van Kooten, Samuel J.; Cranmer, Steven R.

2017-11-01

Magnetic bright points in the solar photosphere, visible in both continuum and G-band images, indicate footpoints of kilogauss magnetic flux tubes extending to the corona. The power spectrum of bright-point motion is thus also the power spectrum of Alfvén wave excitation, transporting energy up flux tubes into the corona. This spectrum is a key input in coronal and heliospheric models. We produce a power spectrum of bright-point motion using radiative magnetohydrodynamic simulations, exploiting spatial resolution higher than can be obtained in present-day observations, while using automated tracking to produce large data quantities. We find slightly higher amounts of power at all frequencies compared to observation-based spectra, while confirming the spectrum shape of recent observations. This also provides a prediction for observations of bright points with DKIST, which will achieve similar resolution and high sensitivity. We also find a granule size distribution in support of an observed two-population distribution, and we present results from tracking passive tracers, which show a similar power spectrum to that of bright points. Finally, we introduce a simplified, laminar model of granulation, with which we explore the roles of turbulence and of the properties of the granulation pattern in determining bright-point motion.

Development of a metallic magnetic calorimeter for high resolution spectroscopy; Entwicklung eines metallischen magnetischen Kalorimeters fuer die hochaufloesende Roentgenspektroskopie

Energy Technology Data Exchange (ETDEWEB)

Linck, M.

2007-05-02

In this thesis the development of a metallic magnetic calorimeter for high resolution detection of single x-ray quanta is described. The detector consists of an X-ray absorber and a paramagnetic temperature sensor. The raise in temperature of the paramagnetic sensor due to the absorption of a single X-ray is measured by the change in magnetization of the sensor using a low-noise SQUID magnetometer. The thermodynamic properties of the detector can be described by a theoretical model based on a mean field approximation. This allows for an optimization of the detector design with respect to signal size. The maximal archivable energy resolution is limited by thermodynamic energy fluctuations between absorber, heat bath and thermometer. An interesting field of application for a metallic magnetic calorimeter is X-ray astronomy and the investigation of X-ray emitting objects. Through high-resolution X-ray spectroscopy it is possible to obtain information about physical processes of even far distant objects. The magnetic calorimeter that was developed in this thesis has a metallic absorber with a quantum efficiency of 98% at 6 keV. The energy resolution of the magnetic calorimeter is EFWHM=2.7 eV at 5.9 keV. The deviation of the detector response from a linear behavior of the detector is only 0.8% at 5.9 keV. (orig.)

Electron beam fabrication and characterization of high- resolution magnetic force microscopy tips

NARCIS (Netherlands)

Ruhrig, M.; Rührig, M.; Porthun, S.; Porthun, S.; Lodder, J.C.; Mc vitie, S.; Heyderman, L.J.; Johnston, A.B.; Chapman, J.N.

1996-01-01

The stray field, magnetic microstructure, and switching behavior of high‐resolution electron beam fabricated thin film tips for magnetic force microscopy (MFM) are investigated with different imaging modes in a transmission electron microscope (TEM). As the tiny smooth carbon needles covered with a

Targeting high-performance liquid chromatography-high-resolution mass spectrometry-solid-phase extraction-nuclear magnetic resonance analysis with high-resolution radical scavenging profiles - bioactive secondary metabolites from the endophytic fungus Penicillium namyslowskii

DEFF Research Database (Denmark)

Wubshet, Sileshi Gizachew; Nyberg, Nils; Tejesvi, Mysore V.

2013-01-01

The high-resolution radical scavenging profile of an extract of the endophytic fungus Penicillium namyslowskii was used to target analysis by high-performance liquid chromatography-high-resolution mass spectrometry-solid-phase extraction-nuclear magnetic resonance spectroscopy, i.e., HPLC...... NMR probe designed for 1.7-mm NMR tubes. To further explore the potential of the above HPLC-HRMS-SPE-NMR platform for analysis of endophytic extracts, six peaks displaying no radical scavenging activity were also analyzed. This allowed unambiguous identification of six metabolites, i...... and griseofulvin, directly from crude extract via HPLC-HRMS-SPE-NMR. Dechlorodehydrogriseofulvin was reported for the first time from nature....

High-resolution records of non-dipole variations in the intensity of the Earth's magnetic field

NARCIS (Netherlands)

de Groot, L.V.

2013-01-01

Our understanding of the short-term behavior of the Earth’s magnetic field is currently mainly hampered by a lack of high-resolution records of geomagnetic intensity variations that are well distributed over the globe and cover the same timespan. Over the past decades many efforts have been made to

An extended magnetic quadrupole lens for a high-resolution nuclear microprobe

Energy Technology Data Exchange (ETDEWEB)

Breese, M.B.H. E-mail: m.breese@surrey.ac.uk; Grime, G.W.; Linford, W.; Harold, M

1999-09-02

This paper describes the design requirements and initial performance of a new style of magnetic quadrupole lens for use in a high-resolution nuclear microprobe, which is presently being constructed in Oxford. Such a microprobe necessitates the use of a small image distance from the exit face of the final quadrupole lens to the image plane in order to produce a large demagnification. This means that the final lens should be as close to the sample chamber as possible. However, with conventional magnetic quadrupoles the current-carrying coils protrude by a typical distance of 10-20 mm beyond the pole face, thereby significantly limiting the minimum image distance. The approach taken here is to recess the coils into the body of the lens, so that they are almost flush with the pole pieces and lens yoke, enabling an image distance of 55 mm. Three-dimensional magnetic field calculations within this lens structure predict that the field in the extended pole piece 'nose' region is only slightly less than that in the main lens body. Experimental field profiles, measured using a Hall probe, are used to confirm these calculations.

An extended magnetic quadrupole lens for a high-resolution nuclear microprobe

International Nuclear Information System (INIS)

Breese, M.B.H.; Grime, G.W.; Linford, W.; Harold, M.

1999-01-01

This paper describes the design requirements and initial performance of a new style of magnetic quadrupole lens for use in a high-resolution nuclear microprobe, which is presently being constructed in Oxford. Such a microprobe necessitates the use of a small image distance from the exit face of the final quadrupole lens to the image plane in order to produce a large demagnification. This means that the final lens should be as close to the sample chamber as possible. However, with conventional magnetic quadrupoles the current-carrying coils protrude by a typical distance of 10-20 mm beyond the pole face, thereby significantly limiting the minimum image distance. The approach taken here is to recess the coils into the body of the lens, so that they are almost flush with the pole pieces and lens yoke, enabling an image distance of 55 mm. Three-dimensional magnetic field calculations within this lens structure predict that the field in the extended pole piece 'nose' region is only slightly less than that in the main lens body. Experimental field profiles, measured using a Hall probe, are used to confirm these calculations

Triple aldose reductase/α-glucosidase/radical scavenging high-resolution profiling combined with high-performance liquid chromatography – high-resolution mass spectrometry – solid-phase extraction – nuclear magnetic resonance spectroscopy for identification of antidiabetic constituents in crude, extract of Radix Scutellariae

DEFF Research Database (Denmark)

Tahtah, Yousof; Kongstad, Kenneth Thermann; Wubshet, Sileshi Gizachew

2015-01-01

high-performance liquid chromatography – high-resolution mass spectrometry – solid-phase extraction – nuclear magnetic resonance spectroscopy. The only α-glucosidase inhibitor was baicalein, whereas main aldose reductase inhibitors in the crude extract were baicalein and skullcapflavone II, and main....../α-glucosidase/radical scavenging high-resolution inhibition profile - allowing proof of concept with Radix Scutellariae crude extract as a polypharmacological herbal drug. The triple bioactivity high-resolution profiles were used to pinpoint bioactive compounds, and subsequent structure elucidation was performed with hyphenated...

Correlation of geothermal springs with sub-surface fault terminations revealed by high-resolution, UAV-acquired magnetic data

Science.gov (United States)

Glen, Jonathan; A.E. Egger,; C. Ippolito,; N.Athens,

2013-01-01

There is widespread agreement that geothermal springs in extensional geothermal systems are concentrated at fault tips and in fault interaction zones where porosity and permeability are dynamically maintained (Curewitz and Karson, 1997; Faulds et al., 2010). Making these spatial correlations typically involves geological and geophysical studies in order to map structures and their relationship to springs at the surface. Geophysical studies include gravity and magnetic surveys, which are useful for identifying buried, intra-basin structures, especially in areas where highly magnetic, dense mafic volcanic rocks are interbedded with, and faulted against less magnetic, less dense sedimentary rock. High-resolution magnetic data can also be collected from the air in order to provide continuous coverage. Unmanned aerial systems (UAS) are well-suited for conducting these surveys as they can provide uniform, low-altitude, high-resolution coverage of an area without endangering crew. In addition, they are more easily adaptable to changes in flight plans as data are collected, and improve efficiency. We have developed and tested a new system to collect magnetic data using small-platform UAS. We deployed this new system in Surprise Valley, CA, in September, 2012, on NASA's SIERRA UAS to perform a reconnaissance survey of the entire valley as well as detailed surveys in key transition zones. This survey has enabled us to trace magnetic anomalies seen in ground-based profiles along their length. Most prominent of these is an intra-basin magnetic high that we interpret as a buried, faulted mafic dike that runs a significant length of the valley. Though this feature lacks surface expression, it appears to control the location of geothermal springs. All of the major hot springs on the east side of the valley lie along the edge of the high, and more specifically, at structural transitions where the high undergoes steps, bends, or breaks. The close relationship between the springs

A flexible coil array for high resolution magnetic resonance imaging at 7 Tesla

International Nuclear Information System (INIS)

Kriegl, R.

2015-01-01

Magnetic resonance imaging (MRI), among other imaging techniques, has become a major backbone of modern medical diagnostics. MRI enables the non-invasive combined, identification of anatomical structures, functional and chemical properties, especially in soft tissues. Nonetheless, applications requiring very high spatial and/or temporal resolution are often limited by the available signal-to-noise ratio (SNR) in MR experiments. Since first clinical applications, image quality in MRI has been constantly improved by applying one or several of the following strategies: increasing the static magnetic field strength, improvement of the radiofrequency (RF) detection system, development of specialized acquisition sequences and optimization of image reconstruction techniques. This work is concerned with the development of highly sensitive RF detection systems for biomedical ultra-high field MRI. In particular, auto-resonant RF coils based on transmission line technology are investigated. These resonators may be fabricated on flexible substrate which enables form-fitting of the RF detector to the target anatomy, leading to a significant SNR gain. The main objective of this work is the development of a flexible RF coil array for high-resolution MRI on a human whole-body 7 T MR scanner. With coil arrays, the intrinsically high SNR of small surface coils may be exploited for an extended field of view. Further, parallel imaging techniques are accessible with RF array technology, allowing acceleration of the image acquisition. Secondly, in this PhD project a novel design for transmission line resonators is developed, that brings an additional degree of freedom in geometric design and enables the fabrication of large multi-turn resonators for high field MR applications. This thesis describes the development, successful implementation and evaluation of novel, mechanically flexible RF devices by analytical and 3D electromagnetic simulations, in bench measurements and in MRI

High resolution neurography of the brachial plexus by 3 Tesla magnetic resonance imaging.

Science.gov (United States)

Cejas, C; Rollán, C; Michelin, G; Nogués, M

2016-01-01

The study of the structures that make up the brachial plexus has benefited particularly from the high resolution images provided by 3T magnetic resonance scanners. The brachial plexus can have mononeuropathies or polyneuropathies. The mononeuropathies include traumatic injuries and trapping, such as occurs in thoracic outlet syndrome due to cervical ribs, prominent transverse apophyses, or tumors. The polyneuropathies include inflammatory processes, in particular chronic inflammatory demyelinating polyneuropathy, Parsonage-Turner syndrome, granulomatous diseases, and radiation neuropathy. Vascular processes affecting the brachial plexus include diabetic polyneuropathy and the vasculitides. This article reviews the anatomy of the brachial plexus and describes the technique for magnetic resonance neurography and the most common pathologic conditions that can affect the brachial plexus. Copyright © 2016 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

High-Resolution Metallic Magnetic Calorimeters for beta-Spectroscopy on 187-Rhenium and Position Resolved X-Ray Spectroscopy

OpenAIRE

Porst, Jan-Patrick

2010-01-01

This thesis describes the development of metallic magnetic calorimeters (MMCs) for high resolution spectroscopy. MMCs are energy dispersive particle detectors based on the calorimetric principle which are typically operated at temperatures below 100 mK. The detectors make use of a paramagnetic temperature sensor to transform the temperature rise upon the absorption of a particle in the detector into a measurable magnetic flux change in a dc-SQUID. The application of MMCs for neutrino mass mea...

Brain Atlas Fusion from High-Thickness Diagnostic Magnetic Resonance Images by Learning-Based Super-Resolution.

Science.gov (United States)

Zhang, Jinpeng; Zhang, Lichi; Xiang, Lei; Shao, Yeqin; Wu, Guorong; Zhou, Xiaodong; Shen, Dinggang; Wang, Qian

2017-03-01

It is fundamentally important to fuse the brain atlas from magnetic resonance (MR) images for many imaging-based studies. Most existing works focus on fusing the atlases from high-quality MR images. However, for low-quality diagnostic images (i.e., with high inter-slice thickness), the problem of atlas fusion has not been addressed yet. In this paper, we intend to fuse the brain atlas from the high-thickness diagnostic MR images that are prevalent for clinical routines. The main idea of our works is to extend the conventional groupwise registration by incorporating a novel super-resolution strategy. The contribution of the proposed super-resolution framework is two-fold. First, each high-thickness subject image is reconstructed to be isotropic by the patch-based sparsity learning. Then, the reconstructed isotropic image is enhanced for better quality through the random-forest-based regression model. In this way, the images obtained by the super-resolution strategy can be fused together by applying the groupwise registration method to construct the required atlas. Our experiments have shown that the proposed framework can effectively solve the problem of atlas fusion from the low-quality brain MR images.

Development of high-resolution two-dimensional magnetic field measurement system by use of printed-circuit technology

Science.gov (United States)

Akimitsu, Moe; Qinghong, Cao; Sawada, Asuka; Hatano, Hironori; Tanabe, Hiroshi; Ono, Yasushi; TS-Group Team

2017-10-01

We have developed a new-types of high-resolution magnetic probe array for our new magnetic reconnection experiments: TS-3U (ST, FRC: R =0.2m, 2017-) and TS-4U (ST, FRC: R =0.5m, 2018-), using the advanced printed-circuit technology. They are equipped with all three-components of magnetic pick-up coils whose size is 1-5mm x 3mm. Each coil is composed of two-sided coil pattern with line width of 0.05mm. We can install two or three printed arrays in a single glass (ceramic) tube for two or three component measurements. Based on this new probe technique, we started high-resolution and high-accuracy measurement of the current sheet thickness and studied its plasma parameter dependence. We found that the thickness of current sheet increases inversely with the guide toroidal field. It is probably determined by the ion gyroradius in agreement with the particle simulation by Horiuchi etc. While the reconnection speed is steady under low guide field condition, it is observed to oscillate in the specific range of guide field, suggesting transition from the quasi-steady reconnection to the intermittent reconnection. Cause and mechanism for intermittent reconnection will be discussed using the current sheet dissipation and dynamic balance between plasma inflow and outflow. This work supported by JSPS KAKENHI Grant Numbers 15H05750, 15K14279 and 17H04863.

Geophysical Modelling and Multi-Scale Studies in the Arctic Seiland Igneous Province: Millimeter to Micrometer Scale Mapping of the Magnetic Sources by High Resolution Magnetic Microscopy

Science.gov (United States)

Pastore, Z.; Church, N. S.; McEnroe, S. A.; Oda, H.; ter Maat, G. W.

2017-12-01

Rocks samples can have wide range of magnetic properties depending on composition, amount of ferromagnetic minerals, grain sizes and microstructures. These influence the magnetic anomalies from the micro to the global scale making the study of the magnetic properties of interest for multiple applications. Later geological processes such as serpentinization can significantly influence these properties and change the nature of the magnetic anomalies. Particularly, magnetic properties such as remanent magnetization and magnetic susceptibility are directly linked to the magnetic mineralogy composition and grain size and can provide useful information about the geological history of the source. Scanning magnetic microscopy is a highly sensitive and high-resolution magnetometric technique for mapping the magnetic field over a planar surface of a rock sample. The device measures the vertical component of the field above the thin sections and the technique offers a spatial resolution down to tens of micrometers and thus can be used to investigate discrete magnetic mineral grains or magnetic textures and structures, and the magnetic history of the sample. This technique allows a direct correlation between the mineral chemistry (through both electron and optical microscopy) and the magnetic properties. We present as case-study three thin section magnetic scans of two dunite samples from the Reinfjord Ultramafic complex, in northern Norway. The selected thin sections show different magnetic properties which reflect the magnetic petrology. One of the thin sections is from a pristine dunite sample; the other two are highly serpentinized with newly formed magnetite found in multiple, few micrometer thick, veins. We present the preliminary results obtained applying a forward modelling approach on the magnetic anomaly maps acquired over the thin sections. Modelling consists of uniformly-magnetized polygonal bodies whose geometry is constrained by the thickness of the thin section

Ultrahigh-Resolution Magnetic Resonance in Inhomogeneous Magnetic Fields: Two-Dimensional Long-Lived-Coherence Correlation Spectroscopy

Science.gov (United States)

Chinthalapalli, Srinivas; Bornet, Aurélien; Segawa, Takuya F.; Sarkar, Riddhiman; Jannin, Sami; Bodenhausen, Geoffrey

2012-07-01

A half-century quest for improving resolution in Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI) has enabled the study of molecular structures, biological interactions, and fine details of anatomy. This progress largely relied on the advent of sophisticated superconducting magnets that can provide stable and homogeneous fields with temporal and spatial variations below ΔB0/B0LLC-COSY) opens the way to overcome both inhomogeneous and homogeneous broadening, which arise from local variations in static fields and fluctuating dipole-dipole interactions, respectively. LLC-COSY makes it possible to obtain ultrahigh resolution two-dimensional spectra, with linewidths on the order of Δν=0.1 to 1 Hz, even in very inhomogeneous fields (ΔB0/B0>10ppm or 5000 Hz at 9.7 T), and can improve resolution by a factor up to 9 when the homogeneous linewidths are determined by dipole-dipole interactions. The resulting LLC-COSY spectra display chemical shift differences and scalar couplings in two orthogonal dimensions, like in “J spectroscopy.” LLC-COSY does not require any sophisticated gradient switching or frequency-modulated pulses. Applications to in-cell NMR and to magnetic resonance spectroscopy (MRS) of selected volume elements in MRI appear promising, particularly when susceptibility variations tend to preclude high resolution.

APES: Acute Precipitating Electron Spectrometer - A High Time Resolution Monodirectional Magnetic Deflection Electron Spectrometer

Science.gov (United States)

Michell, R. G.; Samara, M.; Grubbs, G., II; Ogasawara, K.; Miller, G.; Trevino, J. A.; Webster, J.; Stange, J.

2016-01-01

We present a description of the Acute Precipitating Electron Spectrometer (APES) that was designed and built for the Ground-to-Rocket Electron Electrodynamics Correlative Experiment (GREECE) auroral sounding rocket mission. The purpose was to measure the precipitating electron spectrum with high time resolution, on the order of milliseconds. The trade-off made in order to achieve high time resolution was to limit the aperture to only one look direction. The energy selection was done by using a permanent magnet to separate the incoming electrons, such that the different energies would fall onto different regions of the microchannel plate and therefore be detected by different anodes. A rectangular microchannel plate (MCP) was used (15 mm x 100 mm), and there was a total of 50 discrete anodes under the MCP, each one 15 mm x 1.5 mm, with a 0.5 mm spacing between anodes. The target energy range of APES was 200 eV to 30 keV.

Phase separation and magnetic ordering studied by high resolution neutron diffraction

International Nuclear Information System (INIS)

Caspi, E.N.; Melamud, M.; Pinto, H.; Shaked, H.; Chmaissem, O.; Jorgensen, J.D.; Short, S.

1999-01-01

Complete text of publication follows. In a previous work on the (U 1-x Nd x )Co 2 Ge 2 system, two magnetic transitions were observed in the temperature dependencies of the magnetic susceptibility and in the intensity of the magnetic reflections in neutron diffraction [1]. Because of insufficient resolution, it was not clear whether this is due to clustering or phase separation. In both cases the U-rich regions are expected to order magnetically at higher temperature than the U-poor ones, resulting in two magnetic transitions. In order to resolve this question a temperature dependent TOF neutron diffraction of the x = 0.25 compound has been performed on the SEPD at Argonne's IPNS [2]. The temperature dependent diffractograms were refined by the Rietveld method. It was found that the compound separates into two phases: x = 0.4 (55 wt%) and x = 0.1 (45 wt%). The temperature dependence of the magnetic moment was obtained for each phase, with the transition temperatures: T N (x=0.4) = 130 K, and T N (x=0.1) = 165 K. (author) [1] E. Caspi et al., Phys. Rev. B, 57 (198) 449.; [2] J.D. Jorgensen et al., J. Appl. Cryst. 22 (1989) 321

Magnetic Resonance Super-resolution Imaging Measurement with Dictionary-optimized Sparse Learning

Directory of Open Access Journals (Sweden)

Li Jun-Bao

2017-06-01

Full Text Available Magnetic Resonance Super-resolution Imaging Measurement (MRIM is an effective way of measuring materials. MRIM has wide applications in physics, chemistry, biology, geology, medical and material science, especially in medical diagnosis. It is feasible to improve the resolution of MR imaging through increasing radiation intensity, but the high radiation intensity and the longtime of magnetic field harm the human body. Thus, in the practical applications the resolution of hardware imaging reaches the limitation of resolution. Software-based super-resolution technology is effective to improve the resolution of image. This work proposes a framework of dictionary-optimized sparse learning based MR super-resolution method. The framework is to solve the problem of sample selection for dictionary learning of sparse reconstruction. The textural complexity-based image quality representation is proposed to choose the optimal samples for dictionary learning. Comprehensive experiments show that the dictionary-optimized sparse learning improves the performance of sparse representation.

Multi-wavelength high-resolution observations of a small-scale emerging magnetic flux event and the chromospheric and coronal response

Energy Technology Data Exchange (ETDEWEB)

Vargas Domínguez, Santiago; Kosovichev, Alexander; Yurchyshyn, Vasyl, E-mail: svargas@bbso.njit.edu [Big Bear Solar Observatory, NJIT, 40386 North Shore Lane, Big Bear City, CA 92314-9672 (United States)

2014-10-20

State-of-the-art solar instrumentation is now revealing magnetic activity of the Sun with unprecedented temporal and spatial resolutions. Observations with the 1.6 m aperture New Solar Telescope (NST) of the Big Bear Solar Observatory are making next steps in our understanding of the solar surface structure. Granular-scale magnetic flux emergence and the response of the solar atmosphere are among the key research topics of high-resolution solar physics. As part of a joint observing program with NASA's Interface Region Imaging Spectrograph (IRIS) mission on 2013 August 7, the NST observed active region NOAA 11,810 in the photospheric TiO 7057 Å band with a resolution of pixel size of 0.''034 and chromospheric He I 10830 Å and Hα 6563 Å wavelengths. Complementary data are provided by the Solar Dynamics Observatory (SDO) and Hinode space-based telescopes. The region displayed a group of solar pores, in the vicinity of which we detect a small-scale buoyant horizontal magnetic flux tube causing granular alignments and interacting with the preexisting ambient field in the upper atmospheric layers. Following the expansion of distorted granules at the emergence site, we observed a sudden appearance of an extended surge in the He I 10830 Å data (bandpass of 0.05 Å). The IRIS transition region imaging caught ejection of a hot plasma jet associated with the He I surge. The SDO/HMI data used to study the evolution of the magnetic and Doppler velocity fields reveal emerging magnetic loop-like structures. Hinode/Ca II H and IRIS filtergrams detail the connectivities of the newly emerged magnetic field in the lower solar chromosphere. From these data, we find that the orientation of the emerging magnetic field lines from a twisted flux tube formed an angle of ∼45° with the overlying ambient field. Nevertheless, the interaction of emerging magnetic field lines with the pre-existing overlying field generates high-temperature emission regions and boosts the

Superconducting magnets in high energy physics

International Nuclear Information System (INIS)

Prodell, A.G.

1978-01-01

The applications of superconducting magnets in high energy physics in the last ten years have made feasible developments which are vital to high energy research. These developments include high magnetic field, large volume detectors, such as bubble chambers, required for effective resolution of high energy particle trajectories, particle beam transport magnets, and superconducting focusing and bending magnets for the very high energy accelerators and storage rings needed to pursue the study of interactions between elementary particles. The acceptance of superconductivity as a proven technology in high energy physics was reinforced by the recognition that the existing large accelerators using copper-iron magnets had reached practical limits in terms of magnetic field intensity, cost, space, and energy usage, and that large-volume, high-field, copper-iron magnets were not economically feasible. Some of the superconducting magnets and associated systems being used in and being developed for high energy physics are described

Longitudinal assessment of mouse renal injury using high-resolution anatomic and magnetization transfer MR imaging.

Science.gov (United States)

Wang, Feng; Jiang, Rosie; Takahashi, Keiko; Gore, John; Harris, Raymond C; Takahashi, Takamune; Quarles, C Chad

2014-11-01

The purpose of this study is to evaluate the utility of high-resolution non-invasive endogenous high-field MRI methods for the longitudinal structural and quantitative assessments of mouse kidney disease using the model of unilateral ureter obstruction (UUO). T1-weighted, T2-weighted and magnetization transfer (MT) imaging protocols were optimized to improve the regional contrast in mouse kidney. Conventional T1 and T2 weighted images were collected in UUO mice on day 0 (~3h), day 1, day 3 and day 6 after injury, on a 7 T small animal MRI system. Cortical and medullary thickness, corticomedullary contrast and Magnetization Transfer Ratio (MTR) were assessed longitudinally. Masson trichrome staining was used to histologically assess changes in tissue microstructure. Over the course of UUO progression there were significant (prenal cortical and medullary atrophy, cortical-medullary differentiation and MTR changes provide an endogenous, non-invasive and quantitative evaluation of renal morphology and tissue composition during UUO progression. Copyright © 2014 Elsevier Inc. All rights reserved.

High-Time-Resolution Study of Magnetic Holes in the Solar Wind

Science.gov (United States)

Lazarus, Alan; Kasper, Justin; Stevens, Michael

2003-01-01

The objectives of this investigation are to determine the internal plasma structure of kinetic-scale and larger scale magnetic holes, and to determine their stability, their source mechanism(s), and their spatial extent. It is also of importance to determine the relationship between kinetic-scale holes and long-duration holes. As smaller and smaller magnetic depressions are investigated in order to make this a complete study, a robust criterion is necessary for distinguishing magnetic holes from random or unresolvable fluctuations in the interplanetary magnetic field. In order to resolve this ambiguity, we obtained from the MFI experiments magnetic field measurements from the WIND spacecraft at a time resolution of 46 to 184 ms over certain periods. We have also devised a measure of certainty for magnetic hole detections. The certainty factor, q, is defined as the difference between the mean magnetic field in the hole and the local magnetic field, in units of the local standard deviation of the field strength. For fullest generality, it is necessary to calculate this q over the range of available scales of interest, from 60 ms up to 300 s. This technique establishes a two dimensional matrix of relative probabilities that a hole of some duration (d) might exist in the data set at a given time (t). In identifying q-peaks in time and duration, we also come upon a natural method for distinguishing holes with internal structure from multiple holes in close proximity or holes nested inside of others. If two q-peaks are more than a half-width apart, they are simply said to be separate events.

High-resolution magnetic resonance imaging of rotator cuff tears using a microscopy coil. Noninvasive detection without intraarticular contrast material

International Nuclear Information System (INIS)

Hitachi, Shin; Takase, Kei; Higano, Shuichi; Takahashi, Shoki; Tanaka, Minoru; Tojo, Yuichi; Tabata, Shiro; Majima, Kazuhiro

2011-01-01

The aim of this study was to evaluate the feasibility of high-resolution magnetic resonance imaging (MRI) using a microscopy coil for the diagnosis of rotator cuff tears by comparing the method to conventional MRI and MRI arthrography. A total of 68 shoulders were prospectively studied using a 1.5-T MRI unit. Conventional MRI scans were obtained with a surface coil and high-resolution MRI scans with a microscopy coil. MRI arthrography was performed in 28 shoulders using a surface coil. MRI evaluation of tears of rotator cuff tendons was compared with arthroscopic findings and surgical results. The surgery revealed 40 full-thickness tears, 13 partial-thickness tears, and 15 intact cuffs. In all, 35 (88%) full-thickness tears were correctly diagnosed on conventional MRI and 40 (100%) on high-resolution MRI. MR arthrography delineated 11 of 12 (92%) full-thickness tears. Altogether, 5 (38%) of the partial-thickness tears were detected on conventional MRI, and 12 (92%) were clearly demonstrated on high-resolution MRI. MRI arthrography depicted three (60%) of five partial-thickness tears. High-resolution MRI showed higher sensitivity than conventional MRI (P<0.05) and had values equivalent to those of MRI arthrography for diagnosing partial-thickness tears. High-resolution MRI with a microscopy coil is a feasible, noninvasive technique for diagnosing rotator cuff tears. (author)

High resolution ADC interface to main magnet power supply at the NSLS

International Nuclear Information System (INIS)

Bordoley, M.

1993-01-01

Previous readings of DCCT were limited to 11 bits of resolution with large offsets and drifts, providing inaccurate data. The current design overcomes this limitation by using Analog Device's AD7703 20 bit serial output ADC to digitize the main magnet DCCT at the power supply, and transmit the data serially at 2KHz over to the VME controller

Crocus sativus Petals: Waste or Valuable Resource? The Answer of High-Resolution and High-Resolution Magic Angle Spinning Nuclear Magnetic Resonance.

Science.gov (United States)

Righi, Valeria; Parenti, Francesca; Tugnoli, Vitaliano; Schenetti, Luisa; Mucci, Adele

2015-09-30

Intact Crocus sativus petals were studied for the first time by high-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy, revealing the presence of kinsenoside (2) and goodyeroside A (3), together with 3-hydroxy-γ-butyrolactone (4). These findings were confirmed by HR-NMR analysis of the ethanol extract of fresh petals and showed that, even though carried out rapidly, partial hydrolysis of glucopyranosyloxybutanolides occurs during extraction. On the other hand, kaempferol 3-O-sophoroside (1), which is "NMR-silent" in intact petals, is present in extracts. These results suggest to evaluate the utilization of saffron petals for phytopharmaceutical and nutraceutical purposes to exploit a waste product of massive production of commercial saffron and point to the application of HR-MAS NMR for monitoring bioactive compounds directly on intact petals, avoiding the extraction procedure and the consequent hydrolysis reaction.

Accelerated high-resolution 3D magnetic resonance spectroscopic imaging in the brain At 7 T

International Nuclear Information System (INIS)

Hangel, G.

2015-01-01

With the announcement of the first series of magnetic resonance (MR) scanners with a field strength of 7 Tesla (T) intended for clinical practice, the development of high-performance sequences for higher field strengths has gained importance. Magnetic resonance spectroscopic imaging (MRSI) in the brain currently offers the unique ability to spatially resolve the distribution of multiple metabolites simultaneously. Its big diagnostic potential could be applied to many clinical protocols, for example the assessment of tumour treatment or progress of Multiple Sclerosis. Moving to ultra-high fields like 7 T has the main benefits of increased signal-to-noise ratio (SNR) and improved spectral quality, but brings its own challenges due to stronger field inhomogeneities. Necessary for a robust, flexible and useful MRSI sequence in the brain are high resolutions, shortened measurement times, the possibility for 3D-MRSI and the suppression of spectral contamination by trans-cranial lipids. This thesis addresses these limitations and proposes Hadamard spectroscopic imaging (HSI) as solution for multi-slice MRSI, the application of generalized autocalibrating partially parallel acquisition (GRAPPA) and spiral trajectories for measurement acceleration, non-selective inversion recovery (IR) lipid-suppression as well as combinations of these methods. Further, the optimisation of water suppression for 7 T systems and the acquisition of ultra-high resolution (UHR)-MRSI are discussed. In order to demonstrate the clinical feasibility of these approaches, MRSI measurement results of a glioma patient are presented. The discussion of the obtained results in the context of the state-of-art in 7 T MRSI in the brain, possible future applications as well as potential further improvements of the MRSI sequences conclude this thesis. (author) [de

18/20 T high magnetic field scanning tunneling microscope with fully low voltage operability, high current resolution, and large scale searching ability.

Science.gov (United States)

Li, Quanfeng; Wang, Qi; Hou, Yubin; Lu, Qingyou

2012-04-01

We present a home-built 18/20 T high magnetic field scanning tunneling microscope (STM) featuring fully low voltage (lower than ±15 V) operability in low temperatures, large scale searching ability, and 20 fA high current resolution (measured by using a 100 GOhm dummy resistor to replace the tip-sample junction) with a bandwidth of 3.03 kHz. To accomplish low voltage operation which is important in achieving high precision, low noise, and low interference with the strong magnetic field, the coarse approach is implemented with an inertial slider driven by the lateral bending of a piezoelectric scanner tube (PST) whose inner electrode is axially split into two for enhanced bending per volt. The PST can also drive the same sliding piece to inertial slide in the other bending direction (along the sample surface) of the PST, which realizes the large area searching ability. The STM head is housed in a three segment tubular chamber, which is detachable near the STM head for the convenience of sample and tip changes. Atomic resolution images of a graphite sample taken under 17.6 T and 18.0001 T are presented to show its performance. © 2012 American Institute of Physics

High resolution ADC interface to main magnet power supply at the NSLS

Energy Technology Data Exchange (ETDEWEB)

Bordoley, M.

1993-07-01

Previous readings of DCCT were limited to 11 bits of resolution with large offsets and drifts, providing inaccurate data. The current design overcomes this limitation by using Analog Device`s AD7703 20 bit serial output ADC to digitize the main magnet DCCT at the power supply, and transmit the data serially at 2KHz over to the VME controller.

High resolution ADC interface to main magnet power supply at the NSLS

Energy Technology Data Exchange (ETDEWEB)

Bordoley, M.

1993-01-01

Previous readings of DCCT were limited to 11 bits of resolution with large offsets and drifts, providing inaccurate data. The current design overcomes this limitation by using Analog Device's AD7703 20 bit serial output ADC to digitize the main magnet DCCT at the power supply, and transmit the data serially at 2KHz over to the VME controller.

High resolution photoelectron spectroscopy

International Nuclear Information System (INIS)

Arko, A.J.

1988-01-01

Photoelectron Spectroscopy (PES) covers a very broad range of measurements, disciplines, and interests. As the next generation light source, the FEL will result in improvements over the undulator that are larger than the undulater improvements over bending magnets. The combination of high flux and high inherent resolution will result in several orders of magnitude gain in signal to noise over measurements using synchrotron-based undulators. The latter still require monochromators. Their resolution is invariably strongly energy-dependent so that in the regions of interest for many experiments (h upsilon > 100 eV) they will not have a resolving power much over 1000. In order to study some of the interesting phenomena in actinides (heavy fermions e.g.) one would need resolving powers of 10 4 to 10 5 . These values are only reachable with the FEL

Interpretation of high resolution airborne magnetic data (HRAMD of Ilesha and its environs, Southwest Nigeria, using Euler deconvolution method

Directory of Open Access Journals (Sweden)

Olurin Oluwaseun Tolutope

2017-12-01

Full Text Available Interpretation of high resolution aeromagnetic data of Ilesha and its environs within the basement complex of the geological setting of Southwestern Nigeria was carried out in the study. The study area is delimited by geographic latitudes 7°30′–8°00′N and longitudes 4°30′–5°00′E. This investigation was carried out using Euler deconvolution on filtered digitised total magnetic data (Sheet Number 243 to delineate geological structures within the area under consideration. The digitised airborne magnetic data acquired in 2009 were obtained from the archives of the Nigeria Geological Survey Agency (NGSA. The airborne magnetic data were filtered, processed and enhanced; the resultant data were subjected to qualitative and quantitative magnetic interpretation, geometry and depth weighting analyses across the study area using Euler deconvolution filter control file in Oasis Montag software. Total magnetic intensity distribution in the field ranged from –77.7 to 139.7 nT. Total magnetic field intensities reveal high-magnitude magnetic intensity values (high-amplitude anomaly and magnetic low intensities (low-amplitude magnetic anomaly in the area under consideration. The study area is characterised with high intensity correlated with lithological variation in the basement. The sharp contrast is enhanced due to the sharp contrast in magnetic intensity between the magnetic susceptibilities of the crystalline and sedimentary rocks. The reduced-to-equator (RTE map is characterised by high frequencies, short wavelengths, small size, weak intensity, sharp low amplitude and nearly irregular shaped anomalies, which may due to near-surface sources, such as shallow geologic units and cultural features. Euler deconvolution solution indicates a generally undulating basement, with a depth ranging from −500 to 1000 m. The Euler deconvolution results show that the basement relief is generally gentle and flat, lying within the basement terrain.

High resolution magnetic force microscopy using focused ion beam modified tips

NARCIS (Netherlands)

Phillips, G.N.; Siekman, Martin Herman; Abelmann, Leon; Lodder, J.C.

2002-01-01

Atomic force microscope tips coated by the thermal evaporation of a magnetic 30 nm thick Co film have been modified by focused ion beam milling with Ga+ ions to produce tips suitable for magnetic force microscopy. Such tips possess a planar magnetic element with high magnetic shape anisotropy, an

High-resolution morphologic and ultrashort time-to-echo quantitative magnetic resonance imaging of the temporomandibular joint

Energy Technology Data Exchange (ETDEWEB)

Bae, Won C.; Chang, Eric Y.; Biswas, Reni; Statum, Sheronda; Chung, Christine B. [Veterans Administration San Diego Healthcare System, Department of Radiology, San Diego, CA (United States); University of California, San Diego, School of Medicine, Department of Radiology, San Diego, CA (United States); Tafur, Monica; Du, Jiang; Healey, Robert [University of California, San Diego, School of Medicine, Department of Radiology, San Diego, CA (United States); Kwack, Kyu-Sung [Ajou University Medical Center, Department of Radiology, Wonchon-dong, Yeongtong-gu, Gyeonggi-do, Suwon (Korea, Republic of)

2016-03-15

To implement high-resolution morphologic and quantitative magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ) using ultrashort time-to-echo (UTE) techniques in cadavers and volunteers. This study was approved by the institutional review board. TMJs of cadavers and volunteers were imaged on a 3-T MR system. High-resolution morphologic and quantitative sequences using conventional and UTE techniques were performed in cadaveric TMJs. Morphologic and UTE quantitative sequences were performed in asymptomatic and symptomatic volunteers. Morphologic evaluation demonstrated the TMJ structures in open- and closed-mouth position. UTE techniques facilitated the visualization of the disc and fibrocartilage. Quantitative UTE MRI was successfully performed ex vivo and in vivo, reflecting the degree of degeneration. There was a difference in the mean UTE T2* values between asymptomatic and symptomatic volunteers. MRI evaluation of the TMJ using UTE techniques allows characterization of the internal structure and quantification of the MR properties of the disc. Quantitative UTE MRI can be performed in vivo with short scan times. (orig.)

Project for a high resolution magnetic spectrometer for heavy ions

International Nuclear Information System (INIS)

Birien, P.; Valero, S.

1981-05-01

The energy loss spectrometer presented in this report has an energy resolution of 2x10 -4 with the full solid angle of 5 msr. The maximum magnetic rigidity of the particles analysed is 2.88 Tesla-meters on the optical axis and the total acceptance in energy is 14%. Experiments with reaction angles near 0 0 are possible. Kinematic compensation is adapted to heavy ion physics. In this report, we have paid special attention to the simplicity of the construction and of the use of this spectrometer by experimentalists. This report is addressed both to non-specialists and to future users as well [fr

Hith resolution β-spectroscopy of the isotope 36Cl using magnetic calorimeters

International Nuclear Information System (INIS)

Rotzinger, H.

2006-01-01

This thesis describes the development of a high resolution magnetic calorimeter for the detection of the β-spectrum of the isotope 36 Cl with endpoint energy of 709.6 keV. The temperature rise of a metallic paramagnetic sensor due to an energy deposition is sensed by measuring its magnetization using a sensitive DC-SQUID magnetometer. For a high detection efficiency an 4π gold absorber was used. The heat capacity and the geometry of the absorber is optimally matched by a flat sensor and an optimized meander shaped readout coil. The fabrication of the superconducting structures and the detector setup are described. In addition, the relevant noise sources, the energy resolution and the quantum efficiency are discussed. A measured 36 Cl-spectrum with an energy resolution of ΔE FWHM =750 eV is presented and compared with existing experimental and theoretical data. (orig.)

High resolution spectroscopy in solids by nuclear magnetic resonance; Espectroscopia de alta resolucao em solidos por ressonancia magnetica nuclear

Energy Technology Data Exchange (ETDEWEB)

Bonagamba, T J

1991-07-01

The nuclear magnetic resonance (NMR) techniques for High Resolution Spectroscopy in Solids are described. Also the construction project of a partially home made spectrometer and its applications in the characterization of solid samples are shown in detail. The high resolution spectrometer used is implemented with the double resonance multiple pulses sequences and magic angle spinning (MAS) and can be used with solid and liquid samples. The maximum spinning frequency for the MAS experiment is in excess of 5 Khz, the double resonance sequences can be performed with any type of nucleus, in the variable temperature operating range with nitrogen gas: -120{sup 0} C to +160{sup 0} C, and is fully controlled by a Macintosh IIci microcomputer. (author).

Benefits of GMR sensors for high spatial resolution NDT applications

Science.gov (United States)

Pelkner, M.; Stegemann, R.; Sonntag, N.; Pohl, R.; Kreutzbruck, M.

2018-04-01

Magneto resistance sensors like GMR (giant magneto resistance) or TMR (tunnel magneto resistance) are widely used in industrial applications; examples are position measurement and read heads of hard disk drives. However, in case of non-destructive testing (NDT) applications these sensors, although their properties are outstanding like high spatial resolution, high field sensitivity, low cost and low energy consumption, never reached a technical transfer to an application beyond scientific scope. This paper deals with benefits of GMR/TMR sensors in terms of high spatial resolution testing for different NDT applications. The first example demonstrates the preeminent advantages of MR-elements compared with conventional coils used in eddy current testing (ET). The probe comprises one-wire excitation with an array of MR elements. This led to a better spatial resolution in terms of neighboring defects. The second section concentrates on MFL-testing (magnetic flux leakage) with active field excitation during and before testing. The latter illustrated the capability of highly resolved crack detection of a crossed notch. This example is best suited to show the ability of tiny magnetic field sensors for magnetic material characterization of a sample surface. Another example is based on characterization of samples after tensile test. Here, no external field is applied. The magnetization is only changed due to external load and magnetostriction leading to a field signature which GMR sensors can resolve. This gives access to internal changes of the magnetization state of the sample under test.

Development of an extraction type magnetometer under high pressure and high magnetic fields over 200 kOe in the hybrid magnet

International Nuclear Information System (INIS)

Koyama, K; Miura, S; Okada, H; Watanabe, K

2006-01-01

An extraction-type magnetometer has been developed, which is performed under pressures up to 12 kbar using a miniature high-pressure clamp-cell, in magnetic fields up to 270 kOe using our hybrid magnet and at the temperature range from 1.5 to 300 K. Magnetization curves can be measured for absolute value over 0.04 emu. We confirmed that resolution is about ±0.01 emu under high pressures and high magnetic fields if a sample has the magnetic moment of about 3 emu. For demonstrating the ability of the instrument, high field magnetization curves for SmMn 2 Ge 2 under high pressures are presented

Quadrupole magnetic mapping of the high resolution spectrometers of Thomas Jefferson National Accelerator Laboratory, Hall A. (Q.M.M. project: Quadrupole Magnetic Measurement)

International Nuclear Information System (INIS)

Quemener, Gilles

1997-01-01

This thesis describes the magnetic measurements that have been performed on the superconducting quadrupoles of the High Resolution Spectrometers of TJNAF, Hall A (USA), which are designed to measure particle momentum up to 4 GeV.c -1 with a σp/p = 10 -4 resolution. The mapping method is based on rotating coil technique, the originality being a segmentation of the probe along the quad axis. Together with an accurate magnet modelling, the measurement of the flux variations through the set of rotating coils allows to determine the magnetic field at each point. We use the 3D field formalism, i.e., the Fourier-Bessel expansion of the field obtained by solving the Laplace equation. We describe the QMM method and then the apparatus consisting in two probes of length 1.6 m and 3.2 m built to map the three quadrupoles Q1, Q2, Q3. Data processing uses Fourier analysis. The mapping of the Electron Arm took place in situ in 1996. A first set of results concerns integral measurements including the properties of excitation cycle of the magnets (saturation and hysteresis). Second set of results in terms of local field yields the 3D field maps of the quadrupoles. After having applied corrections to the data we obtain a local field accuracy of 5 Gauss on each component, i.e. an uncertainty of 5.10 -4 relative to the quadrupole central field. We use SNAKE ray-tracing code with the implementation of QMM field maps and obtain preliminary results on HRS optics. (author)

High-resolution 13C nuclear magnetic resonance evidence of phase transition of Rb,Cs-intercalated single-walled nanotubes

KAUST Repository

Bouhrara, M.

2011-09-06

We present 13 C high-resolution magic-angle-turning (MAT) and magic angle spinning nuclear magnetic resonance data of Cs and Rb intercalated single walled carbon nanotubes. We find two distinct phases at different intercalation levels. A simple charge transfer is applicable at low intercalation level. The new phase at high intercalation level is accompanied by a hybridization of alkali (s) orbitals with the carbon (sp2) orbitals of the single walled nanotubes, which indicate bundle surface sites is the most probable alkali site.

Combining scanning tunneling microscopy and synchrotron radiation for high-resolution imaging and spectroscopy with chemical, electronic, and magnetic contrast

International Nuclear Information System (INIS)

Cummings, M.L.; Chien, T.Y.; Preissner, C.; Madhavan, V.; Diesing, D.; Bode, M.; Freeland, J.W.; Rose, V.

2012-01-01

The combination of high-brilliance synchrotron radiation with scanning tunneling microscopy opens the path to high-resolution imaging with chemical, electronic, and magnetic contrast. Here, the design and experimental results of an in-situ synchrotron enhanced x-ray scanning tunneling microscope (SXSTM) system are presented. The system is designed to allow monochromatic synchrotron radiation to enter the chamber, illuminating the sample with x-ray radiation, while an insulator-coated tip (metallic tip apex open for tunneling, electron collection) is scanned over the surface. A unique feature of the SXSTM is the STM mount assembly, designed with a two free-flex pivot, providing an angular degree of freedom for the alignment of the tip and sample with respect to the incoming x-ray beam. The system designed successfully demonstrates the ability to resolve atomic-scale corrugations. In addition, experiments with synchrotron x-ray radiation validate the SXSTM system as an accurate analysis technique for the study of local magnetic and chemical properties on sample surfaces. The SXSTM system's capabilities have the potential to broaden and deepen the general understanding of surface phenomena by adding elemental contrast to the high-resolution of STM. -- Highlights: ► Synchrotron enhanced x-ray scanning tunneling microscope (SXSTM) system designed. ► Unique STM mount design allows angular DOF for tip alignment with x-ray beam. ► System demonstrates ability to resolve atomic corrugations on HOPG. ► Studies show chemical sensitivity with STM tip from photocurrent and tunneling. ► Results show system's ability to study local magnetic (XMCD) properties on Fe films.

High resolution backscattering instruments

International Nuclear Information System (INIS)

Coldea, R.

2001-01-01

The principle of operation of indirect-geometry time-of-flight spectrometers are presented, including the IRIS at the ISIS spallation neutron source. The key features that make those types of spectrometers ideally suited for low-energy spectroscopy are: high energy resolution over a wide dynamic range, and simultaneous measurement over a large momentum transfer range provided by the wide angular detector coverage. To exemplify these features are discussed of single-crystal experiments of the spin dynamics in the two-dimensional frustrated quantum magnet Cs 2 CuCl 4 . (R.P.)

High-resolution magnetic resonance imaging of diurnal variations in rheumatoid arthritis

International Nuclear Information System (INIS)

Nicholas, R.S.

2000-09-01

This thesis describes work that uses high-resolution magnetic resonance imaging (MRI) to give an insight into the aetiology of rheumatoid arthritis (RA) with particular reference to characterising diurnal changes in joint stiffness in the metacarpophalangeal (MCP) joints. The study was performed on a targeted 1.1 T MRI scanner using specialised sequences, including 3-dimensional gradient-echo, magnetisation transfer (MT) and multiple gradient-echo. These enabled tissue-dependent parameters such as MT ratio, effective transverse relaxation time (T 2 *) and proton density (ρ) to be made. Preliminary reproducibility studies of the MRI measurements showed that MT ratio could be measured in vivo to an accuracy of better than 8%. This variation is due to repositioning errors and physiological changes. Equivalent variations in T 2 * and p were 23% and 16% respectively; these poorer figures were contributed to errors in fitting the data to an exponential curve. An MRI study monitoring the diurnal variation of stiffness in RA demonstrated better characterisation of the disease state using MT and T 2 * maps compared to standard gradient-echo imaging. Features associated with arthritis such as bone erosions and cysts were found in the control group and an MT age dependence was measured in the soft tissue on the superior margin of the joint. This region also exhibited a diurnal variation in MT ratio for the patient group. The interaction between this region of tissue and other structures (e.g. the sheath of extensor tendon) within the joint could be a possible cause of joint stiffness. An incidental finding of this study was that Ritchie joint score also showed a diurnal variation. This study has demonstrated that MRI can be used to make reproducible measurements of the diurnal variations in RA. The indication is that the soft tissues in the superior aspect of the joint may be responsible for the symptom of joint stiffness in the MCP joints and future studies should be

Beamline 9.3.2 - a high-resolution, bend-magnet beamline with circular polarization capability

Energy Technology Data Exchange (ETDEWEB)

Moler, E.J.; Hussain, Z.; Howells, M.R. [Lawrence Berkeley National Lab., CA (United States)] [and others

1997-04-01

Beamline 9.3.2 is a high resolution, SGM beamline on an ALS bending magnet with access to photon energies from 30-1500 eV. Features include circular polarization capability, a rotating chamber platform that allows switching between experiments without breaking vacuum, an active feedback system that keeps the beam centered on the entrance slit of the monochromator, and a bendable refocusing mirror. The beamline optics consist of horizontally and vertically focussing mirrors, a Spherical Grating Monochromator (SGM) with movable entrance and exit slits, and a bendable refocussing mirror. In addition, a movable aperature has been installed just upstream of the vertically focussing mirror which can select the x-rays above or below the plane of the synchrotron storage ring, allowing the user to select circularly or linearly polarized light. Circularly polarized x-rays are used to study the magnetic properties of materials. Beamline 9.3.2 can supply left and right circularly polarized x-rays by a computer controlled aperture which may be placed above or below the plane of the synchrotron storage ring. The degree of linear and circular polarization has been measured and calibrated.

High Resolution Thermometry for EXACT

Science.gov (United States)

Panek, J. S.; Nash, A. E.; Larson, M.; Mulders, N.

2000-01-01

High Resolution Thermometers (HRTs) based on SQUID detection of the magnetization of a paramagnetic salt or a metal alloy has been commonly used for sub-nano Kelvin temperature resolution in low temperature physics experiments. The main applications to date have been for temperature ranges near the lambda point of He-4 (2.177 K). These thermometers made use of materials such as Cu(NH4)2Br4 *2H2O, GdCl3, or PdFe. None of these materials are suitable for EXACT, which will explore the region of the He-3/He-4 tricritical point at 0.87 K. The experiment requirements and properties of several candidate paramagnetic materials will be presented, as well as preliminary test results.

Characterisation of carotid plaques with ultrasound elastography: feasibility and correlation with high-resolution magnetic resonance imaging

International Nuclear Information System (INIS)

Naim, Cyrille; Cloutier, Guy; Mercure, Elizabeth; Destrempes, Francois; Qin, Zhao; El-Abyad, Walid; Lanthier, Sylvain; Giroux, Marie-France; Soulez, Gilles

2013-01-01

To evaluate the ability of ultrasound non-invasive vascular elastography (NIVE) strain analysis to characterise carotid plaque composition and vulnerability as determined by high-resolution magnetic resonance imaging (MRI). Thirty-one subjects with 50 % or greater carotid stenosis underwent NIVE and high-resolution MRI of internal carotid arteries. Time-varying strain images (elastograms) of segmented plaques were generated from ultrasonic raw radiofrequency sequences. On MRI, corresponding plaques and components were segmented and quantified. Associations between strain parameters, plaque composition and symptomatology were estimated with curve-fitting regressions and Mann-Whitney tests. Mean stenosis and age were 72.7 % and 69.3 years, respectively. Of 31 plaques, 9 were symptomatic, 17 contained lipid and 7 were vulnerable on MRI. Strains were significantly lower in plaques containing a lipid core compared with those without lipid, with 77-100 % sensitivity and 57-79 % specificity (P < 0.032). A statistically significant quadratic fit was found between strain and lipid content (P < 0.03). Strains did not discriminate symptomatic patients or vulnerable plaques. Ultrasound NIVE is feasible in patients with significant carotid stenosis and can detect the presence of a lipid core with high sensitivity and moderate specificity. Studies of plaque progression with NIVE are required to identify vulnerable plaques. (orig.)

High-resolution imaging and near-infrared spectroscopy of penumbral decay

Science.gov (United States)

Verma, M.; Denker, C.; Balthasar, H.; Kuckein, C.; Rezaei, R.; Sobotka, M.; Deng, N.; Wang, H.; Tritschler, A.; Collados, M.; Diercke, A.; Manrique, S. J. González

2018-06-01

Aims: Combining high-resolution spectropolarimetric and imaging data is key to understanding the decay process of sunspots as it allows us to scrutinize the velocity and magnetic fields of sunspots and their surroundings. Methods: Active region NOAA 12597 was observed on 2016 September 24 with the 1.5-meter GREGOR solar telescope using high-spatial-resolution imaging as well as imaging spectroscopy and near-infrared (NIR) spectropolarimetry. Horizontal proper motions were estimated with local correlation tracking, whereas line-of-sight (LOS) velocities were computed with spectral line fitting methods. The magnetic field properties were inferred with the "Stokes Inversions based on Response functions" (SIR) code for the Si I and Ca I NIR lines. Results: At the time of the GREGOR observations, the leading sunspot had two light bridges indicating the onset of its decay. One of the light bridges disappeared, and an elongated, dark umbral core at its edge appeared in a decaying penumbral sector facing the newly emerging flux. The flow and magnetic field properties of this penumbral sector exhibited weak Evershed flow, moat flow, and horizontal magnetic field. The penumbral gap adjacent to the elongated umbral core and the penumbra in that penumbral sector displayed LOS velocities similar to granulation. The separating polarities of a new flux system interacted with the leading and central part of the already established active region. As a consequence, the leading spot rotated 55° clockwise over 12 h. Conclusions: In the high-resolution observations of a decaying sunspot, the penumbral filaments facing the flux emergence site contained a darkened area resembling an umbral core filled with umbral dots. This umbral core had velocity and magnetic field properties similar to the sunspot umbra. This implies that the horizontal magnetic fields in the decaying penumbra became vertical as observed in flare-induced rapid penumbral decay, but on a very different time-scale.

High resolution NMR spectroscopy of nanocrystalline proteins at ultra-high magnetic field

International Nuclear Information System (INIS)

Sperling, Lindsay J.; Nieuwkoop, Andrew J.; Lipton, Andrew S.; Berthold, Deborah A.; Rienstra, Chad M.

2010-01-01

Magic-angle spinning (MAS) solid-state NMR (SSNMR) spectroscopy of uniformly- 13 C, 15 N labeled protein samples provides insight into atomic-resolution chemistry and structure. Data collection efficiency has advanced remarkably in the last decade; however, the study of larger proteins is still challenged by relatively low resolution in comparison to solution NMR. In this study, we present a systematic analysis of SSNMR protein spectra acquired at 11.7, 17.6 and 21.1 Tesla ( 1 H frequencies of 500, 750, and 900 MHz). For two protein systems-GB1, a 6 kDa nanocrystalline protein and DsbA, a 21 kDa nanocrystalline protein-line narrowing is demonstrated in all spectral regions with increasing field. Resolution enhancement is greatest in the aliphatic region, including methine, methylene and methyl sites. The resolution for GB1 increases markedly as a function of field, and for DsbA, resolution in the C-C region increases by 42%, according to the number of peaks that can be uniquely picked and integrated in the 900 MHz spectra when compared to the 500 MHz spectra. Additionally, chemical exchange is uniquely observed in the highest field spectra for at least two isoleucine Cδ1 sites in DsbA. These results further illustrate the benefits of high-field MAS SSNMR spectroscopy for protein structural studies.

Novel Super-Resolution Approach to Time-Resolved Volumetric 4-Dimensional Magnetic Resonance Imaging With High Spatiotemporal Resolution for Multi-Breathing Cycle Motion Assessment

International Nuclear Information System (INIS)

Li, Guang; Wei, Jie; Kadbi, Mo; Moody, Jason; Sun, August; Zhang, Shirong; Markova, Svetlana; Zakian, Kristen; Hunt, Margie; Deasy, Joseph O.

2017-01-01

Purpose: To develop and evaluate a super-resolution approach to reconstruct time-resolved 4-dimensional magnetic resonance imaging (TR-4DMRI) with a high spatiotemporal resolution for multi-breathing cycle motion assessment. Methods and Materials: A super-resolution approach was developed to combine fast 3-dimensional (3D) cine MRI with low resolution during free breathing (FB) and high-resolution 3D static MRI during breath hold (BH) using deformable image registration. A T1-weighted, turbo field echo sequence, coronal 3D cine acquisition, partial Fourier approximation, and SENSitivity Encoding parallel acceleration were used. The same MRI pulse sequence, field of view, and acceleration techniques were applied in both FB and BH acquisitions; the intensity-based Demons deformable image registration method was used. Under an institutional review board–approved protocol, 7 volunteers were studied with 3D cine FB scan (voxel size: 5 × 5 × 5 mm"3) at 2 Hz for 40 seconds and a 3D static BH scan (2 × 2 × 2 mm"3). To examine the image fidelity of 3D cine and super-resolution TR-4DMRI, a mobile gel phantom with multi-internal targets was scanned at 3 speeds and compared with the 3D static image. Image similarity among 3D cine, 4DMRI, and 3D static was evaluated visually using difference image and quantitatively using voxel intensity correlation and Dice index (phantom only). Multi-breathing-cycle waveforms were extracted and compared in both phantom and volunteer images using the 3D cine as the references. Results: Mild imaging artifacts were found in the 3D cine and TR-4DMRI of the mobile gel phantom with a Dice index of >0.95. Among 7 volunteers, the super-resolution TR-4DMRI yielded high voxel-intensity correlation (0.92 ± 0.05) and low voxel-intensity difference (<0.05). The detected motion differences between TR-4DMRI and 3D cine were −0.2 ± 0.5 mm (phantom) and −0.2 ± 1.9 mm (diaphragms). Conclusion: Super-resolution TR-4DMRI has been

Novel Super-Resolution Approach to Time-Resolved Volumetric 4-Dimensional Magnetic Resonance Imaging With High Spatiotemporal Resolution for Multi-Breathing Cycle Motion Assessment

Energy Technology Data Exchange (ETDEWEB)

Li, Guang, E-mail: lig2@mskcc.org [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York (United States); Wei, Jie [Department of Computer Science, City College of New York, New York, New York (United States); Kadbi, Mo [Philips Healthcare, MR Therapy Cleveland, Ohio (United States); Moody, Jason; Sun, August; Zhang, Shirong; Markova, Svetlana; Zakian, Kristen; Hunt, Margie; Deasy, Joseph O. [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York (United States)

2017-06-01

Purpose: To develop and evaluate a super-resolution approach to reconstruct time-resolved 4-dimensional magnetic resonance imaging (TR-4DMRI) with a high spatiotemporal resolution for multi-breathing cycle motion assessment. Methods and Materials: A super-resolution approach was developed to combine fast 3-dimensional (3D) cine MRI with low resolution during free breathing (FB) and high-resolution 3D static MRI during breath hold (BH) using deformable image registration. A T1-weighted, turbo field echo sequence, coronal 3D cine acquisition, partial Fourier approximation, and SENSitivity Encoding parallel acceleration were used. The same MRI pulse sequence, field of view, and acceleration techniques were applied in both FB and BH acquisitions; the intensity-based Demons deformable image registration method was used. Under an institutional review board–approved protocol, 7 volunteers were studied with 3D cine FB scan (voxel size: 5 × 5 × 5 mm{sup 3}) at 2 Hz for 40 seconds and a 3D static BH scan (2 × 2 × 2 mm{sup 3}). To examine the image fidelity of 3D cine and super-resolution TR-4DMRI, a mobile gel phantom with multi-internal targets was scanned at 3 speeds and compared with the 3D static image. Image similarity among 3D cine, 4DMRI, and 3D static was evaluated visually using difference image and quantitatively using voxel intensity correlation and Dice index (phantom only). Multi-breathing-cycle waveforms were extracted and compared in both phantom and volunteer images using the 3D cine as the references. Results: Mild imaging artifacts were found in the 3D cine and TR-4DMRI of the mobile gel phantom with a Dice index of >0.95. Among 7 volunteers, the super-resolution TR-4DMRI yielded high voxel-intensity correlation (0.92 ± 0.05) and low voxel-intensity difference (<0.05). The detected motion differences between TR-4DMRI and 3D cine were −0.2 ± 0.5 mm (phantom) and −0.2 ± 1.9 mm (diaphragms). Conclusion: Super-resolution TR-4

A Simple Approach for Obtaining High Resolution, High Sensitivity ¹H NMR Metabolite Spectra of Biofluids with Limited Mass Supply

Energy Technology Data Exchange (ETDEWEB)

Hu, Jian Zhi; Rommereim, Donald N.; Wind, Robert A.; Minard, Kevin R.; Sears, Jesse A.

2006-11-01

A simple approach is reported that yields high resolution, high sensitivity ¹H NMR spectra of biofluids with limited mass supply. This is achieved by spinning a capillary sample tube containing a biofluid at the magic angle at a frequency of about 80Hz. A 2D pulse sequence called ¹H PASS is then used to produce a high-resolution ¹H NMR spectrum that is free from magnetic susceptibility induced line broadening. With this new approach a high resolution ¹H NMR spectrum of biofluids with a volume less than 1.0 µl can be easily achieved at a magnetic field strength as low as 7.05T. Furthermore, the methodology facilitates easy sample handling, i.e., the samples can be directly collected into inexpensive and disposable capillary tubes at the site of collection and subsequently used for NMR measurements. In addition, slow magic angle spinning improves magnetic field shimming and is especially suitable for high throughput investigations. In this paper first results are shown obtained in a magnetic field of 7.05T on urine samples collected from mice using a modified commercial NMR probe.

Determining the Accuracy of Paleomagnetic Remanence and High-Resolution Chronostratigraphy for Sedimentary Rocks using Rock Magnetics

Science.gov (United States)

Kodama, K. P.

2017-12-01

The talk will consider two broad topics in rock magnetism and paleomagnetism: the accuracy of paleomagnetic remanence and the use of rock magnetics to measure geologic time in sedimentary sequences. The accuracy of the inclination recorded by sedimentary rocks is crucial to paleogeographic reconstructions. Laboratory compaction experiments show that inclination shallows on the order of 10˚-15˚. Corrections to the inclination can be made using the effects of compaction on the directional distribution of secular variation recorded by sediments or the anisotropy of the magnetic grains carrying the ancient remanence. A summary of all the compaction correction studies as of 2012 shows that 85% of sedimentary rocks studied have enjoyed some amount of inclination shallowing. Future work should also consider the effect of grain-scale strain on paleomagnetic remanence. High resolution chronostratigraphy can be assigned to a sedimentary sequence using rock magnetics to detect astronomically-forced climate cycles. The power of the technique is relatively quick, non-destructive measurements, the objective identification of the cycles compared to facies interpretations, and the sensitivity of rock magnetics to subtle changes in sedimentary source. An example of this technique comes from using rock magnetics to identify astronomically-forced climate cycles in three globally distributed occurrences of the Shuram carbon isotope excursion. The Shuram excursion may record the oxidation of the world ocean in the Ediacaran, just before the Cambrian explosion of metazoans. Using rock magnetic cyclostratigraphy, the excursion is shown to have the same duration (8-9 Myr) in southern California, south China and south Australia. Magnetostratigraphy of the rocks carrying the excursion in California and Australia shows a reversed to normal geomagnetic field polarity transition at the excursion's nadir, thus supporting the synchroneity of the excursion globally. Both results point to a

Definition of pertinent parameters for the evaluation of articular cartilage repair tissue with high-resolution magnetic resonance imaging

International Nuclear Information System (INIS)

Marlovits, Stefan; Striessnig, Gabriele; Resinger, Christoph T.; Aldrian, Silke M.; Vecsei, Vilmos; Imhof, Herwig; Trattnig, Siegfried

2004-01-01

To evaluate articular cartilage repair tissue after biological cartilage repair, we propose a new technique of non-invasive, high-resolution magnetic resonance imaging (MRI) and define a new classification system. For the definition of pertinent variables the repair tissue of 45 patients treated with three different techniques for cartilage repair (microfracture, autologous osteochondral transplantation, and autologous chondrocyte transplantation) was analyzed 6 and 12 months after the procedure. High-resolution imaging was obtained with a surface phased array coil placed over the knee compartment of interest and adapted sequences were used on a 1 T MRI scanner. The analysis of the repair tissue included the definition and rating of nine pertinent variables: the degree of filling of the defect, the integration to the border zone, the description of the surface and structure, the signal intensity, the status of the subchondral lamina and subchondral bone, the appearance of adhesions and the presence of synovitis. High-resolution MRI, using a surface phased array coil and specific sequences, can be used on every standard 1 or 1.5 T MRI scanner according to the in-house standard protocols for knee imaging in patients who have had cartilage repair procedures without substantially prolonging the total imaging time. The new classification and grading system allows a subtle description and suitable assessment of the articular cartilage repair tissue

High-Resolution Powder Diffractometer HRPT for Thermal Neutrons at SINQ

International Nuclear Information System (INIS)

Fischer, P.; Koch, M.; Koennecke, M.; Pomjakushin, V.; Schefer, J.; Schlumpf, N.

1999-01-01

The new neutron powder diffractometer at the Swiss continuous spallation neutron source SINQ is designed as a flexible instrument for high resolution [best values δd/d: ( -3 with d = lattice spacing in the high resolution or high intensity modes, respectively]. It uses large scattering angles 2Θ M = 120 deg or 90 deg of the monochromator, a 28 cm high, vertically focusing wafer type Ge(hkk) monochromator and a position-sensitive 3 He detector(3.6 bar) produced by Cerca at Romans, France. It has 1600 (25x64) detectors with an angular separation of 0.1 deg and includes modern electronics developed by E. Berruyer, Cerca and PSI. The SICS software of PSI controls the instrument with a server running on an unix workstation and clients written in Java through the TCP/IP network. The design principles and first experiences are presented. The interdisciplinary applications of HRPT will permit high-resolution refinement of chemical and magnetic structures as well as phase analysis including the detection of defects and internal microstrain. In particular real-time investigations of chemical or structural changes and of magnetic phase transitions in crystalline, quasicrystalline, amorphous and liquid samples including technically interesting new materials are possible. (author)

Study of $\\overline{p}$-Nucleus Interaction with a High Resolution Magnetic Spectrometer

CERN Multimedia

2002-01-01

This experiment uses the high resolution, large solid angle and large momentum acceptance magnetic spectrometer SPES~II to study the interaction between @* and complex nuclei in the following experiments: \\\\ \\\\ \\item 1)~~~~A(@*, @*)A. Angular distribution of @* elastically scattered from |1|2C, |4|0Ca and |2|0|8Pb. \\item 2)~~~~A(@*, @*')A*. Excitation energy spectra and some angular distributions of @* inelastically scattered from |1|2C, |4|0Ca and |2|0|8Pb up to an excitation energy of &prop.~100~MeV. \\item 3)~~~~A(@*, p)A^z^-^1 (@*). Excitation energy spectra for knock out reaction on |6Li, |1|2C, |6|3Cu and |2|0|9Bi at several angles. \\end{enumerate}\\\\ \\\\ Any beam momentum between 300 MeV/c and 800 MeV/c will be suitable for this experiment. In order to vary the effect of strong absorption of @* by nuclei, elastic and inelastic scattering will be performed at two or three different @* momenta (depending on the way LEAR will be operated) down to 300~MeV/c.

The last frontier? High-resolution, near-bottom measurements of the Hawaiian Jurassic magnetic anomaly sequence

Science.gov (United States)

Tivey, M.; Tominaga, M.; Sager, W. W.

2012-12-01

The Jurassic sequence of marine magnetic anomalies i.e. older than M29 remain the last part of the marine magnetic anomaly sequence of the geomagnetic polarity timescale (GPTS) that can be gleaned from the ocean crustal record. While Jurassic crust is present in several areas of the world's ocean basins, the oldest and arguably best preserved sequence is in the western Pacific where three lineations sets (Japanese, Hawaiian and Phoenix) converge on the oldest remaining ocean crust on the planet (i.e. crust that has not been subducted). The magnetic anomalies in these 3 lineation sets are marked by low amplitude, relatively indistinct anomalies (tiny wiggles) that collectively have been called the Jurassic quiet Zone (JQZ). Over the past 20 years we have been working on resolving the character and origin of these anomalies with various technologies to improve our resolution of this period. Following an aeromagnetic survey that revealed the possible presence of lineated anomalies older than M29 in the Japanese lineations, we conducted a deeptow magnetometer survey of the Japanese sequence in 1992. In 2002/03 we extended and confirmed this deeptow record with a deeptowed sidescan and magnetometer survey of the Japanese lineation sequence by tying in ODP Hole 801C and extending the anomaly sequence between M29 and M44. These surveys reveal remarkably fast reversals that are lineated and decrease in intensity back in time until M38, prior to which the sequence becomes somewhat confused (the LAZ or low amplitude zone) before recovering in both amplitude and lineated character around Hole 801C (M42). These results are partially supported by recently reported terrestrial magnetostratigraphy records that show the existence of reversals back to M38. A Jurassic GPTS was constructed from this Japanese anomaly sequence, but the overall global significance of the reversal sequence and systematic field intensity changes require confirmation from crustal records created at

High resolution magnetic resonance imaging of urethral anatomy in continent nulliparous pregnant women

International Nuclear Information System (INIS)

Preyer, Oliver; Brugger, Peter C.; Laml, Thomas; Hanzal, Engelbert; Prayer, Daniela; Umek, Wolfgang

2011-01-01

Introduction: To quantify the distribution of morphologic appearances of urethral anatomy and measure variables of urethral sphincter anatomy in continent, nulliparous, pregnant women by high resolution magnetic resonance imaging (MRI). Materials and methods: We studied fifteen women during their first pregnancy. We defined and quantified bladder neck and urethral morphology on axial and sagittal MR images from healthy, continent women. Results: The mean (±standard deviation) total transverse urethral diameter, anterior–posterior diameter, unilateral striated sphincter muscle thickness, and striated sphincter length were 15 ± 2 mm (range: 12–19 mm), 15 ± 2 mm (range: 11–20 mm), 2 ± 1 mm (range: 1–4 mm), and 13 ± 3 mm (range: 9–18 mm) respectively. The mean (±standard deviation) total urethral length on sagittal scans was 22 ± 3 mm (range: 17.6–26.4 mm). Discussion: Advances in MR technique combined with anatomical and histological findings will provide an insight to understand how changes in urethral anatomy might affect the continence mechanisms in pregnant and non-pregnant, continent or incontinent individuals.

A high resolution electromagnetic calorimeter based on lead-tungstate crystals

Czech Academy of Sciences Publication Activity Database

Aleksandrov, D. V.; Burachas, S.F.; Ippolitov, M.S.; Mareš, Jiří A.; Polák, Karel

2005-01-01

Roč. 550, - (2005), s. 169-184 ISSN 0168-9002 Institutional research plan: CEZ:AV0Z10100521 Keywords : PbWO 3 * high resolution electromagnetic calorimeter Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.224, year: 2005

Compact High Resolution SANS using very cold neutrons (VCN-SANS)

International Nuclear Information System (INIS)

Kennedy, S.; Yamada, M.; Iwashita, Y.; Geltenbort, P.; Bleuel, M.; Shimizu, H.

2011-01-01

SANS (Small Angle Neutron Scattering) is a popular method for elucidation of nano-scale structures. However science continually challenges SANS for higher performance, prompting exploration of ever-more exotic and expensive technologies. We propose a compact high resolution SANS, using very cold neutrons, magnetic focusing lens and a wide-angle spherical detector. This system will compete with modern 40 m pinhole SANS in one tenth of the length, matching minimum Q, Q-resolution and dynamic range. It will also probe dynamics using the MIEZE method. Our prototype lens (a rotating permanent-magnet sextupole), focuses a pulsed neutron beam over 3-5 nm wavelength and has measured SANS from micelles and polymer blends. (authors)

Computer-assisted superimposition of magnetic resonance and high-resolution technetium-99m-HMPAO and thallium-201 SPECT images of the brain

International Nuclear Information System (INIS)

Holman, B.L.; Zimmerman, R.E.; Johnson, K.A.; Carvalho, P.A.; Schwartz, R.B.; Loeffler, J.S.; Alexander, E.; Pelizzari, C.A.; Chen, G.T.

1991-01-01

A method for registering three-dimensional CT, MR, and PET data sets that require no special patient immobilization or other precise positioning measures was adapted to high-resolution SPECT and MRI and was applied in 14 subjects [five normal volunteers, four patients with dementia (Alzheimer's disease), two patients with recurrent glioblastoma, and three patients with focal lesions (stroke, arachnoid cyst and head trauma)]. T2-weighted axial magnetic resonance images and transaxial 99mTc-HMPAO and 201Tl images acquired with an annular gamma camera were merged using an objective registration (translation, rotation and rescaling) program. In the normal subjects and patients with dementia and focal lesions, focal areas of high uptake corresponded to gray matter structures. Focal lesions observed on MRI corresponded to perfusion defects on SPECT. In the patients who had undergone surgical resection of glioblastoma followed by interstitial brachytherapy, increased 201Tl corresponding to recurrent tumor could be localized from the superimposed images. The method was evaluated by measuring the residuals in all subjects and translational errors due to superimposition of deep structures in the 12 subjects with normal thalamic anatomy and 99mTc-HMPAO uptake. This method for superimposing magnetic resonance and high-resolution SPECT images of the brain is a useful technique for correlating regional function with brain anatomy

High-efficiency transmision neutron polarizer for high-resolution double crystal diffractometer

International Nuclear Information System (INIS)

Ioffe, A.; Krist, T.; Mezei, F.; Gordeev, G.; Ibrayev, B.

1997-01-01

An efficient transmission geometry neutron polarizer for the high-resolution double crystal diffractometer at HMI (λ=4.8 A) is described. A polarization of about 94% was achieved and the polarized neutron beam intensity amounts to 40% of the nonpolarized beam intensity. This opens up wide possibilities for the study of magnetic small-angle scattering for extremely small momentum transfer (Q∝10 -5 A -1 ). (orig.)

Quantifying uncertainty in Transcranial Magnetic Stimulation - A high resolution simulation study in ICBM space.

Science.gov (United States)

Toschi, Nicola; Keck, Martin E; Welt, Tobias; Guerrisi, Maria

2012-01-01

Transcranial Magnetic Stimulation offers enormous potential for noninvasive brain stimulation. While it is known that brain tissue significantly "reshapes" induced field and charge distributions, most modeling investigations to-date have focused on single-subject data with limited generality. Further, the effects of the significant uncertainties which exist in the simulation (i.e. brain conductivity distributions) and stimulation (e.g. coil positioning and orientations) setup have not been quantified. In this study, we construct a high-resolution anisotropic head model in standard ICBM space, which can be used as a population-representative standard for bioelectromagnetic simulations. Further, we employ Monte-Carlo simulations in order to quantify how uncertainties in conductivity values propagate all the way to induced field and currents, demonstrating significant, regionally dependent dispersions in values which are commonly assumed "ground truth". This framework can be leveraged in order to quantify the effect of any type of uncertainty in noninvasive brain stimulation and bears relevance in all applications of TMS, both investigative and therapeutic.

Recent applications of gas chromatography with high-resolution mass spectrometry.

Science.gov (United States)

Špánik, Ivan; Machyňáková, Andrea

2018-01-01

Gas chromatography coupled to high-resolution mass spectrometry is a powerful analytical method that combines excellent separation power of gas chromatography with improved identification based on an accurate mass measurement. These features designate gas chromatography with high-resolution mass spectrometry as the first choice for identification and structure elucidation of unknown volatile and semi-volatile organic compounds. Gas chromatography with high-resolution mass spectrometry quantitative analyses was previously focused on the determination of dioxins and related compounds using magnetic sector type analyzers, a standing requirement of many international standards. The introduction of a quadrupole high-resolution time-of-flight mass analyzer broadened interest in this method and novel applications were developed, especially for multi-target screening purposes. This review is focused on the development and the most interesting applications of gas chromatography coupled to high-resolution mass spectrometry towards analysis of environmental matrices, biological fluids, and food safety since 2010. The main attention is paid to various approaches and applications of gas chromatography coupled to high-resolution mass spectrometry for non-target screening to identify contaminants and to characterize the chemical composition of environmental, food, and biological samples. The most interesting quantitative applications, where a significant contribution of gas chromatography with high-resolution mass spectrometry over the currently used methods is expected, will be discussed as well. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Probing High Temperature Superconductors with Magnetometry in Ultrahigh Magnetic Fields

Energy Technology Data Exchange (ETDEWEB)

Li, Lu [Univ. of Michigan, Ann Arbor, MI (United States)

2017-07-26

The objective of this research is to investigate the high-field magnetic properties of high temperature superconductors, materials that conduct electricity without loss. A technique known as high-resolution torque magnetometry that was developed to directly measure the magnetization of high temperature superconductors. This technique was implemented using the 65 Tesla pulsed magnetic field facility that is part of the National High Magnetic Field Laboratory at Los Alamos National Laboratory. This research addressed unanswered questions about the interplay between magnetism and superconductivity, determine the electronic structure of high temperature superconductors, and shed light on the mechanism of high temperature superconductivity and on potential applications of these materials in areas such as energy generation and power transmission. Further applications of the technology resolve the novel physical phenomena such as correlated topological insulators, and spin liquid state in quantum magnets.

High spatial resolution and high brightness ion beam probe for in-situ elemental and isotopic analysis

Science.gov (United States)

Long, Tao; Clement, Stephen W. J.; Bao, Zemin; Wang, Peizhi; Tian, Di; Liu, Dunyi

2018-03-01

A high spatial resolution and high brightness ion beam from a cold cathode duoplasmatron source and primary ion optics are presented and applied to in-situ analysis of micro-scale geological material with complex structural and chemical features. The magnetic field in the source as well as the influence of relative permeability of magnetic materials on source performance was simulated using COMSOL to confirm the magnetic field strength of the source. Based on SIMION simulation, a high brightness and high spatial resolution negative ion optical system has been developed to achieve Critical (Gaussian) illumination mode. The ion source and primary column are installed on a new Time-of-Flight secondary ion mass spectrometer for analysis of geological samples. The diameter of the ion beam was measured by the knife-edge method and a scanning electron microscope (SEM). Results show that an O2- beam of ca. 5 μm diameter with a beam intensity of ∼5 nA and an O- beam of ca. 5 μm diameter with a beam intensity of ∼50 nA were obtained, respectively. This design will open new possibilities for in-situ elemental and isotopic analysis in geological studies.

Potentials of high resolution magnetic resonance imaging versus computed tomography for preoperative local staging of colon cancer

International Nuclear Information System (INIS)

Rollven, Erik; Blomqvist, Lennart; Holm, Torbjorn; Glimelius, Bengt; Loerinc, Esther

2013-01-01

Background: Preoperative identification of locally advanced colon cancer is of importance in order to properly plan treatment. Purpose: To study high resolution T2-weighted magnetic resonance imaging (MRI) versus computed tomography (CT) for preoperative staging of colon cancer with surgery and histopathology as reference standard. Material and Methods: Twenty-eight patients with a total of 29 tumors were included. Patients were examined on a 1.5 T MR unit using a phased array body coil. T2 turbo spin-echo high resolution sequences were obtained in a coronal, transverse, and perpendicular plane to the long axis of the colon at the site of the tumor. Contrast-enhanced CT was performed using a protocol for metastasis staging. The examinations were independently evaluated by two gastrointestinal radiologists using criteria adapted to imaging for prediction of T-stage, N-stage, and extramural venous invasion. Based on the T-stage, tumors were divided in to locally advanced (T3cd-T4) and not locally advanced (T1-T3ab). Surgical and histopathological findings served as reference standard. Results: Using MRI, T-stage, N-stage, and extramural venous invasion were correctly predicted for each observer in 90% and 93%, 72% and 69%, and 82% and 78% of cases, respectively. With CT the corresponding results were 79% and 76%, 72% and 72%, 78% and 67%. For MRI inter-observer agreements (Kappa statistics) were 0.79, 0.10, and 0.76. For CT the corresponding results were 0.64, 0.66, and 0.22. Conclusion: Patients with locally advanced colon cancer, defined as tumor stage T3cd-T4, can be identified by both high resolution MRI and CT, even when CT is performed with a metastasis staging protocol. MRI may have an advantage, due to its high soft tissue discrimination, to identify certain prognostic factors such as T-stage and extramural venous invasion

Potentials of high resolution magnetic resonance imaging versus computed tomography for preoperative local staging of colon cancer

Energy Technology Data Exchange (ETDEWEB)

Rollven, Erik; Blomqvist, Lennart [Dept. of Diagnostic Radiology, Karolinska Univ. Hospital Solna, Stockholm (Sweden); Dept. of Molecular Medicine and Surgery, Karolinska Inst., Stockholm (Sweden)], e-mail: erik.rollven@ki.se; Holm, Torbjorn [Dept. of Molecular Medicine and Surgery, Karolinska Inst., Stockholm (Sweden); Dept. of Surgery, Karolinska Univ. Hospital Solna, Stockholm (Sweden); Glimelius, Bengt [Dept. of Radiology, Oncology and Radiation Science, Uppsala Univ., Uppsala (Sweden); Dept. of Oncology and Pathology, Karolinska Inst., Stockholm (Sweden); Loerinc, Esther [Dept. of Oncology and Pathology, Karolinska Inst., Stockholm (Sweden); Dept. of Pathology, Karolinska Univ. Hospital, Solna, Sweden (Sweden)

2013-09-15

Background: Preoperative identification of locally advanced colon cancer is of importance in order to properly plan treatment. Purpose: To study high resolution T2-weighted magnetic resonance imaging (MRI) versus computed tomography (CT) for preoperative staging of colon cancer with surgery and histopathology as reference standard. Material and Methods: Twenty-eight patients with a total of 29 tumors were included. Patients were examined on a 1.5 T MR unit using a phased array body coil. T2 turbo spin-echo high resolution sequences were obtained in a coronal, transverse, and perpendicular plane to the long axis of the colon at the site of the tumor. Contrast-enhanced CT was performed using a protocol for metastasis staging. The examinations were independently evaluated by two gastrointestinal radiologists using criteria adapted to imaging for prediction of T-stage, N-stage, and extramural venous invasion. Based on the T-stage, tumors were divided in to locally advanced (T3cd-T4) and not locally advanced (T1-T3ab). Surgical and histopathological findings served as reference standard. Results: Using MRI, T-stage, N-stage, and extramural venous invasion were correctly predicted for each observer in 90% and 93%, 72% and 69%, and 82% and 78% of cases, respectively. With CT the corresponding results were 79% and 76%, 72% and 72%, 78% and 67%. For MRI inter-observer agreements (Kappa statistics) were 0.79, 0.10, and 0.76. For CT the corresponding results were 0.64, 0.66, and 0.22. Conclusion: Patients with locally advanced colon cancer, defined as tumor stage T3cd-T4, can be identified by both high resolution MRI and CT, even when CT is performed with a metastasis staging protocol. MRI may have an advantage, due to its high soft tissue discrimination, to identify certain prognostic factors such as T-stage and extramural venous invasion.

Iron in the Fire: Searching for Fire's Magnetic Fingerprint using Controlled Heating Experiments, High-Resolution FORCs, IRM Coercivity Spectra, and Low-Temperature Remanence Experiments

Science.gov (United States)

Lippert, P. C.; Reiners, P. W.

2014-12-01

Evidence for recent climate-wildfire linkages underscores the need for better understanding of relationships between wildfire and major climate shifts in Earth history, which in turn offers the potential for prognoses for wildfire and human adaptations to it. In particular, what are the links between seasonality and wildfire frequency and severity, and what are the feedbacks between wildfire, landscape evolution, and biogeochemical cycles, particularly the carbon and iron cycles? A key first step in addressing these questions is recovering well-described wildfire records from a variety of paleolandscapes and paleoclimate regimes. Although charcoal and organic biomarkers are commonly used indicators of fire, taphonomic processes and time-consuming analytical preparations often preclude their routine use in some environments and in high-stratigraphic resolution paleowildfire surveying. The phenomenological relationship between fire and magnetic susceptibility can make it a useful surveying tool, but increased magnetic susceptibility in sediments is not unique to fire, and thus limits its diagnostic power. Here we utilize component-specific rock magnetic methods and analytical techniques to identify the rock magnetic fingerprint of wildfire. We use a custom-designed air furnace, a series of iron-free laboratory soils, natural saprolites and soils, and fuels from Arizona Ponderosa pine forests and grasslands to simulate wildfire in a controlled and monitored environment. Soil-ash residues and soil and fuel controls were then characterized using First Order Reversal Curve (FORC) patterns, DC backfield IRM coercivity spectra, low-temperature SIRM demagnetization behavior, and low-temperature cycling of room-temperature SIRM behavior. We will complement these magnetic analyses with high-resolution TEM of magnetic extracts. Here we summarize the systematic changes to sediment magnetism as pyrolitized organic matter is incorporated into artificial and natural soils. These

SPIRAL2/DESIR high resolution mass separator

Energy Technology Data Exchange (ETDEWEB)

Kurtukian-Nieto, T., E-mail: kurtukia@cenbg.in2p3.fr [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Baartman, R. [TRIUMF, 4004 Wesbrook Mall, Vancouver B.C., V6T 2A3 (Canada); Blank, B.; Chiron, T. [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Davids, C. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Delalee, F. [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Duval, M. [GANIL, CEA/DSM-CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France); El Abbeir, S.; Fournier, A. [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Lunney, D. [CSNSM-IN2P3-CNRS, Université de Paris Sud, F-91405 Orsay (France); Méot, F. [BNL, Upton, Long Island, New York (United States); Serani, L. [Centre d’Études Nucléaires de Bordeaux Gradignan, Université Bordeaux 1-CNRS/IN2P3, BP 120, F-33175 Gradignan Cedex (France); Stodel, M.-H.; Varenne, F. [GANIL, CEA/DSM-CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France); and others

2013-12-15

DESIR is the low-energy part of the SPIRAL2 ISOL facility under construction at GANIL. DESIR includes a high-resolution mass separator (HRS) with a designed resolving power m/Δm of 31,000 for a 1 π-mm-mrad beam emittance, obtained using a high-intensity beam cooling device. The proposed design consists of two 90-degree magnetic dipoles, complemented by electrostatic quadrupoles, sextupoles, and a multipole, arranged in a symmetric configuration to minimize aberrations. A detailed description of the design and results of extensive simulations are given.

Resolution, efficiency and stability of HPGe detector operating in a magnetic field at various gamma-ray energies

International Nuclear Information System (INIS)

Szymanska, K.; Achenbach, P.; Agnello, M.; Botta, E.; Bracco, A.; Bressani, T.; Camera, F.; Cederwall, B.; Feliciello, A.; Ferro, F.; Gerl, J.; Iazzi, F.; Kavatsyuk, M.; Kojouharov, I.; Pochodzalla, J.; Raciti, G.; Saito, T.R.; Sanchez Lorente, A.; Tegner, P.-E.; Wieland, O.

2008-01-01

The use of High Purity Germanium detectors (HPGe) has been planned in some future experiments of hadronic physics. The crystals will be located close to large spectrometers where the magnetic fringing field will not be negligible and their performances might change. Moreover high precision is required in these experiments. The contribution of magnetic field presence and long term measurements is unique. In this paper the results of systematic measurements of the resolution, stability and efficiency of a crystal operating inside a magnetic field of 0.8 T, using radioactive sources in the energy range from 0.08 to 1.33 MeV, are reported. The measurements have been repeated during several months in order to test if any permanent damage occurred. The resolution at 1.117 and 1.332 MeV gamma-rays from a 60 Co source has been measured at different magnetic fields in the range of 0-0.8 T and the results are compared with the previous data

High-Resolution 3T MR Imaging of the Triangular Fibrocartilage Complex.

Science.gov (United States)

von Borstel, Donald; Wang, Michael; Small, Kirstin; Nozaki, Taiki; Yoshioka, Hiroshi

2017-01-10

This study is intended as a review of 3Tesla (T) magnetic resonance (MR) imaging of the triangular fibrocartilage complex (TFCC). The recent advances in MR imaging, which includes high field strength magnets, multi-channel coils, and isotropic 3-dimensional (3D) sequences have enabled the visualization of precise TFCC anatomy with high spatial and contrast resolution. In addition to the routine wrist protocol, there are specific techniques used to optimize 3T imaging of the wrist; including driven equilibrium sequence (DRIVE), parallel imaging, and 3D imaging. The coil choice for 3T imaging of the wrist depends on a number of variables, and the proper coil design selection is critical for high-resolution wrist imaging with high signal and contrast-to-noise ratio. The TFCC is a complex structure and is composed of the articular disc (disc proper), the triangular ligament, the dorsal and volar radioulnar ligaments, the meniscus homologue, the ulnar collateral ligament (UCL), the extensor carpi ulnaris (ECU) tendon sheath, and the ulnolunate and ulnotriquetral ligaments. The Palmer classification categorizes TFCC lesions as traumatic (type 1) or degenerative (type 2). In this review article, we present clinical high-resolution MR images of normal TFCC anatomy and TFCC injuries with this classification system.

High-resolution magnetic resonance imaging of arthritic pathology in the rat knee

Energy Technology Data Exchange (ETDEWEB)

Carpenter, T.A. (Herchel Smith Lab. for Medicinal Chemistry, Cambridge Univ. (United Kingdom)); Everett, J.R. (Smith Kline Beecham Pharmaceuticals, Betchworth (United Kingdom)); Hall, L.D. (Herchel Smith Lab. for Medicinal Chemistry, Cambridge Univ. (United Kingdom)); Harper, G.P. (Smith Kline Beecham Pharmaceuticals, Welwyn (United Kingdom)); Hodgson, R.J. (Herchel Smith Lab. for Medicinal Chemistry, Cambridge Univ. (United Kingdom)); James, M.F. (Smith Kline Beecham Pharmaceuticals, Harlow (United Kingdom)); Watson, P.J. (Herchel Smith Lab. for Medicinal Chemistry, Cambridge Univ. (United Kingdom))

1994-08-01

High-resolution magnetic resonance imaging (MRI) has been used to visualise the changes that occur in both soft tissue and bone during antigen-induced, monoarticular arthritis (AIMA) of the rat knee. Extensive optimisation studies were performed in order to minimise the time of the experiments and to maximise both the signal-to-noise ratio and the contrast in the MR images. The study was cross-sectional rather than longitudinal and at each of the 13 time points studied during the progression of the disease, corresponding X-radiographs and histological sections were obtained. Interpretation of the spin echo MR images was aided by the use of chemical shift-selective imaging, magnetisation transfer contrast and relaxation time experiments, as well as by correlation with the histology and X-radiography data. The MR images clearly show invasion of the synovium by an inflammatory pannus which spreads over the articular cartilage and invades the bone, leading to erosion and later remodelling. Two distinct types of bony erosion were observed: focal erosions, especially at the margins of the joint, and subchondral erosions. It is concluded that MRI provides a sensitive, non-invasive method for investigating both early-stage inflammatory changes and late-stage bony changes in the knee joints of the arthritic rat. (orig.)

High-resolution magnetic resonance imaging of arthritic pathology in the rat knee

International Nuclear Information System (INIS)

Carpenter, T.A.; Everett, J.R.; Hall, L.D.; Harper, G.P.; Hodgson, R.J.; James, M.F.; Watson, P.J.

1994-01-01

High-resolution magnetic resonance imaging (MRI) has been used to visualise the changes that occur in both soft tissue and bone during antigen-induced, monoarticular arthritis (AIMA) of the rat knee. Extensive optimisation studies were performed in order to minimise the time of the experiments and to maximise both the signal-to-noise ratio and the contrast in the MR images. The study was cross-sectional rather than longitudinal and at each of the 13 time points studied during the progression of the disease, corresponding X-radiographs and histological sections were obtained. Interpretation of the spin echo MR images was aided by the use of chemical shift-selective imaging, magnetisation transfer contrast and relaxation time experiments, as well as by correlation with the histology and X-radiography data. The MR images clearly show invasion of the synovium by an inflammatory pannus which spreads over the articular cartilage and invades the bone, leading to erosion and later remodelling. Two distinct types of bony erosion were observed: focal erosions, especially at the margins of the joint, and subchondral erosions. It is concluded that MRI provides a sensitive, non-invasive method for investigating both early-stage inflammatory changes and late-stage bony changes in the knee joints of the arthritic rat. (orig.)

Feasibility of high-resolution one-dimensional relaxation imaging at low magnetic field using a single-sided NMR scanner applied to articular cartilage

Science.gov (United States)

Rössler, Erik; Mattea, Carlos; Stapf, Siegfried

2015-02-01

Low field Nuclear Magnetic Resonance increases the contrast of the longitudinal relaxation rate in many biological tissues; one prominent example is hyaline articular cartilage. In order to take advantage of this increased contrast and to profile the depth-dependent variations, high resolution parameter measurements are carried out which can be of critical importance in an early diagnosis of cartilage diseases such as osteoarthritis. However, the maximum achievable spatial resolution of parameter profiles is limited by factors such as sensor geometry, sample curvature, and diffusion limitation. In this work, we report on high-resolution single-sided NMR scanner measurements with a commercial device, and quantify these limitations. The highest achievable spatial resolution on the used profiler, and the lateral dimension of the sensitive volume were determined. Since articular cartilage samples are usually bent, we also focus on averaging effects inside the horizontally aligned sensitive volume and their impact on the relaxation profiles. Taking these critical parameters into consideration, depth-dependent relaxation time profiles with the maximum achievable vertical resolution of 20 μm are discussed, and are correlated with diffusion coefficient profiles in hyaline articular cartilage in order to reconstruct T2 maps from the diffusion-weighted CPMG decays of apparent relaxation rates.

Sudden flux change studies in high field superconducting accelerator magnets

International Nuclear Information System (INIS)

Feher, S.; Bordini, B.; Carcagno, R.; Makulski, A.; Orris, D.F.; Pischalnikov, Y.M.; Sylvester, C.; Tartaglia, M.; Tompkins, J.C.; Zlobin, A.V.

2004-01-01

As part of the High Field Magnet Program at Fermilab many magnets have been tested which utilize multi strand Rutherford type cable made of state-of-the art Nb 3 Sn strands. During these magnet tests we observed sudden flux changes by monitoring coil voltages and the magnetic field close to the magnets. These flux changes might be linked to magnet instabilities. The voltage spike signals were correlated with quench antenna signals, a strong indication that these are magnet phenomena. With a new high resolution voltage spike detection system, we were able to observe the detailed structure of the spikes. Two fundamentally different signal shapes were distinguished, most likely generated by different mechanisms

High-resolution magnetic measurements of HTSC

Czech Academy of Sciences Publication Activity Database

Janů, Zdeněk; Novák, Miloslav; Tsoi, G.

272-276, - (2004), e1099-e1101 ISSN 0304-8853 R&D Projects: GA ČR GA102/02/0994; GA AV ČR IAA1010104 Institutional research plan: CEZ:AV0Z1010914 Keywords : superconductivity * low-dimensional systems * resonance scattering Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.031, year: 2004

Effects of display resolution and size on primary diagnosis of chest images using a high-resolution electronic work station

International Nuclear Information System (INIS)

Fuhrman, C.R.; Cooperstein, L.A.; Herron, J.; Good, W.F.; Good, B.; Gur, D.; Maitz, G.; Tabor, E.; Hoy, R.J.

1987-01-01

To evaluate the acceptability of electronically displayed planar images, the authors have a high-resolution work station. This system utilizes a high-resolution film digitizer (100-micro resolution) interfaced to a mainframe computer and two high-resolution (2,048 X 2,048) display devices (Azuray). In a clinically simulated multiobserver blind study (19 cases and five observers) a prodetermined series of reading sessions is stored on magnetic disk and is transferred to the displays while the preceding set of images is being reviewed. Images can be linearly processed on the fly into 2,000 X 2,000 full resolution, 1,000 X 1,000 minified display, or 1,000 X 1,000 interpolated for full-size display. Results of the study indicate that radiologists accept but do not like significant minification (more than X2), and they rate 2,000 X 2,000 images as having better diagnostic quality than 1,000 X 1,000 images

High-resolution metallic magnetic calorimeters for β-spectroscopy on 187rhenium and position resolved X-ray spectroscopy

International Nuclear Information System (INIS)

Porst, Jan-Patrick

2011-01-01

This thesis describes the development of metallic magnetic calorimeters (MMCs) for high resolution spectroscopy. MMCs are energy dispersive particle detectors based on the calorimetric principle which are typically operated at temperatures below 100 mK. The detectors make use of a paramagnetic temperature sensor to transform the temperature rise upon the absorption of a particle in the detector into a measurable magnetic flux change in a dc-SQUID. The application of MMCs for neutrino mass measurements and their advantages with respect to other approaches are discussed. In view of this application the development of an MMC optimized for β-endpoint spectroscopy on 187 rhenium is presented. A fully micro-fabricated X-ray detector is characterized and performs close to design values. Furthermore, a new technique to more efficiently couple rhenium absorbers mechanically and thermally to the sensor was developed and successfully tested. By employing a metallic contact, signal rise times faster than 5 μs could be observed with superconducting rhenium absorbers. In addition to the single pixel detectors, an alternative approach of reading out multiple pixels was developed in this work, too. Here, the individual absorbers have a different thermal coupling to only one temperature sensor resulting in a distribution of different pulse shapes. Straightforward position discrimination by means of rise time analysis is demonstrated for a four pixel MMC and a thermal model of the detector is provided. Unprecedented so far, an energy resolution of less than ΔE FWHM <5 eV for 5.9 keV X-rays was achieved across all absorbers. (orig.)

Relating speech production to tongue muscle compressions using tagged and high-resolution magnetic resonance imaging

Science.gov (United States)

Xing, Fangxu; Ye, Chuyang; Woo, Jonghye; Stone, Maureen; Prince, Jerry

2015-03-01

The human tongue is composed of multiple internal muscles that work collaboratively during the production of speech. Assessment of muscle mechanics can help understand the creation of tongue motion, interpret clinical observations, and predict surgical outcomes. Although various methods have been proposed for computing the tongue's motion, associating motion with muscle activity in an interdigitated fiber framework has not been studied. In this work, we aim to develop a method that reveals different tongue muscles' activities in different time phases during speech. We use fourdimensional tagged magnetic resonance (MR) images and static high-resolution MR images to obtain tongue motion and muscle anatomy, respectively. Then we compute strain tensors and local tissue compression along the muscle fiber directions in order to reveal their shortening pattern. This process relies on the support from multiple image analysis methods, including super-resolution volume reconstruction from MR image slices, segmentation of internal muscles, tracking the incompressible motion of tissue points using tagged images, propagation of muscle fiber directions over time, and calculation of strain in the line of action, etc. We evaluated the method on a control subject and two postglossectomy patients in a controlled speech task. The normal subject's tongue muscle activity shows high correspondence with the production of speech in different time instants, while both patients' muscle activities show different patterns from the control due to their resected tongues. This method shows potential for relating overall tongue motion to particular muscle activity, which may provide novel information for future clinical and scientific studies.

High resolution method for the magnetic axis localization for multipole magnets on the base of the garnet films technology

International Nuclear Information System (INIS)

Gertsev, K.F.; Gribkov, V.L.; Liskov, V.A.; Chervonenkis, A.J.

1992-01-01

The methods of stretched wires for the localization of the magnetic axis may be inconvenient sometimes in accelerators and colliders of very high energies because of high gradients, large lengths and small apertures. High gradients may deform the wires due to the nonzero magnetic susceptibility and microscopic ferromagnetic particles on their surface. Long wires have large sagittas and small apertures of magnets limit the transversal working domains for the measuring devices. Precision optics magnets possess extreme parameters, in particular, in interaction regions. The magneto-optic (MO) methods of the measurements present some new possibilities for the solution of the above problems. The use of MO films for magnetic field visualization and mapping was proposed and shown that on the basis of Bi-substituted iron garnet films and MO Faraday effect it's possible to obtain the quantitative vector maps of complicated magnetic field structure. Later this was described on a large scale. This method was discussed in terms of its applicability to the magnetic axis localization in quadrupoles of accelerators. In our opinion, the films technology has great advantages as compared with the colloidal solution. In this paper the principles and variants of the films method are presented and further development of the method under discussion is described

High-resolution functional MRI of the human amygdala at 7 T

Energy Technology Data Exchange (ETDEWEB)

Sladky, Ronald, E-mail: ronald.sladky@meduniwien.ac.at [MR Centre of Excellence, Medical University of Vienna, Lazarettgasse 14, 1090 Vienna (Austria); Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna (Austria); Baldinger, Pia; Kranz, Georg S. [Department of Psychiatry and Psychotherapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna (Austria); Tröstl, Jasmin [MR Centre of Excellence, Medical University of Vienna, Lazarettgasse 14, 1090 Vienna (Austria); Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna (Austria); Höflich, Anna; Lanzenberger, Rupert [Department of Psychiatry and Psychotherapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna (Austria); Moser, Ewald [MR Centre of Excellence, Medical University of Vienna, Lazarettgasse 14, 1090 Vienna (Austria); Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna (Austria); Windischberger, Christian, E-mail: christian.windischberger@meduniwien.ac.at [MR Centre of Excellence, Medical University of Vienna, Lazarettgasse 14, 1090 Vienna (Austria); Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna (Austria)

2013-05-15

Functional magnetic resonance imaging (fMRI) has become the primary non-invasive method for investigating the human brain function. With an increasing number of ultra-high field MR systems worldwide possibilities of higher spatial and temporal resolution in combination with increased sensitivity and specificity are expected to advance detailed imaging of distinct cortical brain areas and subcortical structures. One target region of particular importance to applications in psychiatry and psychology is the amygdala. However, ultra-high field magnetic resonance imaging of these ventral brain regions is a challenging endeavor that requires particular methodological considerations. Ventral brain areas are particularly prone to signal losses arising from strong magnetic field inhomogeneities along susceptibility borders. In addition, physiological artifacts from respiration and cardiac action cause considerable fluctuations in the MR signal. Here we show that, despite these challenges, fMRI data from the amygdala may be obtained with high temporal and spatial resolution combined with increased signal-to-noise ratio. Maps of neural activation during a facial emotion discrimination paradigm at 7 T are presented and clearly show the gain in percental signal change compared to 3 T results, demonstrating the potential benefits of ultra-high field functional MR imaging also in ventral brain areas.

High-resolution functional MRI of the human amygdala at 7 T

International Nuclear Information System (INIS)

Sladky, Ronald; Baldinger, Pia; Kranz, Georg S.; Tröstl, Jasmin; Höflich, Anna; Lanzenberger, Rupert; Moser, Ewald; Windischberger, Christian

2013-01-01

Functional magnetic resonance imaging (fMRI) has become the primary non-invasive method for investigating the human brain function. With an increasing number of ultra-high field MR systems worldwide possibilities of higher spatial and temporal resolution in combination with increased sensitivity and specificity are expected to advance detailed imaging of distinct cortical brain areas and subcortical structures. One target region of particular importance to applications in psychiatry and psychology is the amygdala. However, ultra-high field magnetic resonance imaging of these ventral brain regions is a challenging endeavor that requires particular methodological considerations. Ventral brain areas are particularly prone to signal losses arising from strong magnetic field inhomogeneities along susceptibility borders. In addition, physiological artifacts from respiration and cardiac action cause considerable fluctuations in the MR signal. Here we show that, despite these challenges, fMRI data from the amygdala may be obtained with high temporal and spatial resolution combined with increased signal-to-noise ratio. Maps of neural activation during a facial emotion discrimination paradigm at 7 T are presented and clearly show the gain in percental signal change compared to 3 T results, demonstrating the potential benefits of ultra-high field functional MR imaging also in ventral brain areas

Three-dimensional true FISP for high-resolution imaging of the whole brain

International Nuclear Information System (INIS)

Schmitz, B.; Hagen, T.; Reith, W.

2003-01-01

While high-resolution T1-weighted sequences, such as three-dimensional magnetization-prepared rapid gradient-echo imaging, are widely available, there is a lack of an equivalent fast high-resolution sequence providing T2 contrast. Using fast high-performance gradient systems we show the feasibility of three-dimensional true fast imaging with steady-state precession (FISP) to fill this gap. We applied a three-dimensional true-FISP protocol with voxel sizes down to 0.5 x 0.5 x 0.5 mm and acquisition times of approximately 8 min on a 1.5-T Sonata (Siemens, Erlangen, Germany) magnetic resonance scanner. The sequence was included into routine brain imaging protocols for patients with cerebrospinal-fluid-related intracranial pathology. Images from 20 patients and 20 healthy volunteers were evaluated by two neuroradiologists with respect to diagnostic image quality and artifacts. All true-FISP scans showed excellent imaging quality free of artifacts in patients and volunteers. They were valuable for the assessment of anatomical and pathologic aspects of the included patients. High-resolution true-FISP imaging is a valuable adjunct for the exploration and neuronavigation of intracranial pathologies especially if cerebrospinal fluid is involved. (orig.)

Effect of magnetic quadrupole lens alignment on a nuclear microprobe resolution

International Nuclear Information System (INIS)

Kolinko, S.V.; Ponomarev, A.G.

2016-01-01

The paper reports the research trends in developing probe-forming systems with high demagnification and analysis factors that limit a nuclear microprobe resolution. Parasitic aberrations caused by tilts and offsets of magnetic quadrupoles are studied in terms of their effect on probe parameters on a target. The most common arrangements of probe-forming systems such as a triplet and “Russian quadruplet” with separated geometry are considered. The accuracy prerequisites for the positioning of the quadrupoles are defined, and practical guidelines for alignment of probe-forming systems with high demagnification factors are suggested.

Detection of tannins in modern and fossil barks and in plant residues by high-resolution solid-state 13C nuclear magnetic resonance

Science.gov (United States)

Wilson, M.A.; Hatcher, P.G.

1988-01-01

Bark samples isolated from brown coal deposits in Victoria, Australia, and buried wood from Rhizophora mangle have been studies by high-resolution solid-state nuclear magnetic resonance (NMR) techniques. Dipolar dephasing 13C NMR appears to be a useful method of detecting the presence of tannins in geochemical samples including barks, buried woods, peats and leaf litter. It is shown that tannins are selectively preserved in bark during coalification to the brown coal stage. ?? 1988.

High-resolution structural characterization and magnetic properties of epitaxial Ce-doped yttrium iron garnet thin films

Science.gov (United States)

Li, Zhong; Vikram Singh, Amit; Rastogi, Ankur; Gazquez, Jaume; Borisevich, Albina Y.; Mishra, Rohan; Gupta, Arunava

2017-07-01

Thin films of magnetic garnet materials, e.g. yttrium iron garnet (Y3Fe5O12, YIG), are useful for a variety of applications including microwave integrated circuits and spintronics. Substitution of rare earth ions, such as cerium, is known to enhance the magneto-optic Kerr effect (MOKE) as compared to pure YIG. Thin films of Ce0.75Y2.25Fe5O12 (Ce:YIG) have been grown using the pulsed laser deposition (PLD) technique and their crystal structure examined using high resolution scanning transmission electron microscopy. Homogeneous substitution of Ce in YIG, without oxidation to form a separate CeO2 phase, can be realized in a narrow process window with resulting enhancement of the MOKE signal. The thermally generated signal due to spin Seebeck effect for the optimally doped Ce:YIG films has also been investigated.

High resolution and high voltage electron microscopy at the University of California, Berkeley

International Nuclear Information System (INIS)

Thomas, G.; Westmacott, K.H.

1978-01-01

Recent applications of high-resolution and high-voltage techniques at Berkely are described, using 100-kV TEMs and a standard 650-keV HVEM: grain boundary precipitation in Al--Zn, lattice imaging of grain boundaries in ceramics, steels, phase transitions and magnetic properties of ferrites, lattice defects, precipitation in Al--Si and behavior of interstitial dislocations under electron irradiation, effect of oxide films on loop formation in Al--Mg, and polytypism in magnesium Sialon. 13 refs. 12 figs

High resolution NMR theory and chemical applications

CERN Document Server

Becker, Edwin D

2012-01-01

High Resolution NMR: Theory and Chemical Applications discusses the principles and theory of nuclear magnetic resonance and how this concept is used in the chemical sciences. This book is written at an intermediate level, with mathematics used to augment verbal descriptions of the phenomena. This text pays attention to developing and interrelating four approaches - the steady state energy levels, the rotating vector picture, the density matrix, and the product operator formalism. The style of this book is based on the assumption that the reader has an acquaintance with the general principles of quantum mechanics, but no extensive background in quantum theory or proficiency in mathematics is required. This book begins with a description of the basic physics, together with a brief account of the historical development of the field. It looks at the study of NMR in liquids, including high resolution NMR in the solid state and the principles of NMR imaging and localized spectroscopy. This book is intended to assis...

Principles of high resolution NMR in solids

CERN Document Server

Mehring, Michael

1983-01-01

The field of Nuclear Magnetic Resonance (NMR) has developed at a fascinating pace during the last decade. It always has been an extremely valuable tool to the organic chemist by supplying molecular "finger print" spectra at the atomic level. Unfortunately the high resolution achievable in liquid solutions could not be obtained in solids and physicists and physical chemists had to live with unresolved lines open to a wealth of curve fitting procedures and a vast amount of speculations. High resolution NMR in solids seemed to be a paradoxon. Broad structure­ less lines are usually encountered when dealing with NMR in solids. Only with the recent advent of mUltiple pulse, magic angle, cross-polarization, two-dimen­ sional and multiple-quantum spectroscopy and other techniques during the last decade it became possible to resolve finer details of nuclear spin interactions in solids. I have felt that graduate students, researchers and others beginning to get involved with these techniques needed a book which trea...

High resolution NMR theory and chemical applications

CERN Document Server

Becker, Edwin D

1999-01-01

High Resolution NMR provides a broad treatment of the principles and theory of nuclear magnetic resonance (NMR) as it is used in the chemical sciences. It is written at an "intermediate" level, with mathematics used to augment, rather than replace, clear verbal descriptions of the phenomena. The book is intended to allow a graduate student, advanced undergraduate, or researcher to understand NMR at a fundamental level, and to see illustrations of the applications of NMR to the determination of the structure of small organic molecules and macromolecules, including proteins. Emphasis is on the study of NMR in liquids, but the treatment also includes high resolution NMR in the solid state and the principles of NMR imaging and localized spectroscopy. Careful attention is given to developing and interrelating four approaches - steady state energy levels, the rotating vector picture, the density matrix, and the product operator formalism. The presentation is based on the assumption that the reader has an acquaintan...

Cerebrospinal fluid metabolic profiles in multiple sclerosis and degenerative dementias obtained by high resolution proton magnetic resonance spectroscopy

International Nuclear Information System (INIS)

Vion-Dury, J.; Confort-Gouny, S.; Maillet, S.; Cozzone, P.J.; Nicoli, F.; Gastaut, J.L.

1996-01-01

We have analyzed the cerebrospinal fluid (CSF) of 19 patients with multiple sclerosis (MS), 12 patients with degenerative dementia and 17 control patients using in vitro high resolution proton magnetic resonance spectroscopy (MRS) at 400 MHz. The CSF metabolic profile is slightly modified in MS patients (increased lactate and fructose concentrations, decreased creatinine and phenylalanine concentrations) and is not correlated with the intensity of the intrathecal inflammation. Proton MRS of CSF does not differentiate relapsing-remitting MS and primary progressive MS. We have not detected any specific abnormal resonance in native or lyophilized CSF. The CSF metabolic profile of demented patients is much more altered (increased concentration of lactate, pyruvate, alanine, lysine, valine, leucine-isoleucine, tyrosine, glutamine) and is in agreement with a brain oxidative metabolism impairment as already described in Alzheimer's disease. Unassigned abnormal but non specific or constant resonances have been detected on MR spectra of demented patients. CSF inositol concentration is also increased in the CSF of patients with Alzheimer's disease. In vitro high resolution proton MRS of the CSF constitutes a new and original way to explore CSF for the differential and/or early diagnosis of dementias, as a complement to in vivo proton cerebral MRS. (authors). 22 refs., 4 figs., 2 tabs

Cerebrospinal fluid metabolic profiles in multiple sclerosis and degenerative dementias obtained by high resolution proton magnetic resonance spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Vion-Dury, J.; Confort-Gouny, S.; Maillet, S.; Cozzone, P.J. [Centre Hospitalier Universitaire de la Timone, 13 - Marseille (France); Nicoli, F. [Centre Hospitalier Universitaire de la Timone, 13 - Marseille (France)]|[Hopital Sainte-Marguerite, 13 - Marseille (France); Gastaut, J.L. [Hopital Sainte-Marguerite, 13 - Marseille (France)

1996-07-01

We have analyzed the cerebrospinal fluid (CSF) of 19 patients with multiple sclerosis (MS), 12 patients with degenerative dementia and 17 control patients using in vitro high resolution proton magnetic resonance spectroscopy (MRS) at 400 MHz. The CSF metabolic profile is slightly modified in MS patients (increased lactate and fructose concentrations, decreased creatinine and phenylalanine concentrations) and is not correlated with the intensity of the intrathecal inflammation. Proton MRS of CSF does not differentiate relapsing-remitting MS and primary progressive MS. We have not detected any specific abnormal resonance in native or lyophilized CSF. The CSF metabolic profile of demented patients is much more altered (increased concentration of lactate, pyruvate, alanine, lysine, valine, leucine-isoleucine, tyrosine, glutamine) and is in agreement with a brain oxidative metabolism impairment as already described in Alzheimer`s disease. Unassigned abnormal but non specific or constant resonances have been detected on MR spectra of demented patients. CSF inositol concentration is also increased in the CSF of patients with Alzheimer`s disease. In vitro high resolution proton MRS of the CSF constitutes a new and original way to explore CSF for the differential and/or early diagnosis of dementias, as a complement to in vivo proton cerebral MRS. (authors). 22 refs., 4 figs., 2 tabs.

High resolution eddy current microscopy

Science.gov (United States)

Lantz, M. A.; Jarvis, S. P.; Tokumoto, H.

2001-01-01

We describe a sensitive scanning force microscope based technique for measuring local variations in resistivity by monitoring changes in the eddy current induced damping of a cantilever with a magnetic tip oscillating above a conducting sample. To achieve a high sensitivity, we used a cantilever with an FeNdBLa particle mounted on the tip. Resistivity measurements are demonstrated on a silicon test structure with a staircase doping profile. Regions with resistivities of 0.0013, 0.0041, and 0.022 Ω cm are clearly resolved with a lateral resolution of approximately 180 nm. For this range of resistivities, the eddy current induced damping is found to depend linearly on the sample resistivity.

Torsional resonance mode magnetic force microscopy: enabling higher lateral resolution magnetic imaging without topography-related effects

International Nuclear Information System (INIS)

Kaidatzis, A; García-Martín, J M

2013-01-01

We present experimental work that reveals the benefits of performing magnetic force microscopy measurements employing the torsional resonance mode of cantilever oscillation. This approach provides two clear advantages: the ability of performing magnetic imaging without topography-related interference and the significant lateral resolution improvement (approximately 15%). We believe that this work demonstrates a significant improvement to a versatile magnetic imaging technique widely used in academia and in industry. (paper)

Mechanism of high-resolution STM/AFM imaging with functionalized tips

Czech Academy of Sciences Publication Activity Database

Hapala, Prokop; Kichin, G.; Wagner, C.; Tautz, F.S.; Temirov, R.; Jelínek, Pavel

2014-01-01

Roč. 90, č. 8 (2014), "085421-1"-"085421-9" ISSN 1098-0121 R&D Projects: GA ČR(CZ) GC14-16963J Grant - others:AVČR(CZ) M100101207 Institutional support: RVO:68378271 Keywords : AFM * STM * high resolution Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.736, year: 2014

A high-resolution x-ray spectrometer for a kaon mass measurement

Energy Technology Data Exchange (ETDEWEB)

Phelan, Kevin, E-mail: kevin.phelan@oeaw.ac.at [Stefan Meyer Institute for Subatomic Physics of The Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna (Austria); Suzuki, Ken; Zmeskal, Johann [Stefan Meyer Institute for Subatomic Physics of The Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna (Austria); Tortorella, Daniele [Payr Engineering GmbH, Wiederschwing 25, A-9564 Patergassen (Austria); Bühler, Matthias; Hertrich, Theo [Low Temperature Solutions UG, Bahnhofstraße 21, D-85737 Ismaning (Germany)

2017-02-11

The ASPECT consortium (Adaptable Spectrometer Enabled by Cryogenic Technology) is currently constructing a generalised cryogenic platform for cryogenic detector work which will be able to accommodate a wide range of sensors. The cryogenics system is based on a small mechanical cooler with a further adiabatic demagnetisation stage and will work with cryogenic detectors at sub-Kelvin temperatures. The commercial aim of the consortium is to produce a compact, user-friendly device with an emphasis on reliability and portability which can easily be transported for specialised on-site work, such as beam-lines or telescope facilities. The cryogenic detector platform will accommodate a specially developed cryogenic sensor, either a metallic magnetic calorimeter or a magnetic penetration-depth thermometer. The detectors will be designed to work in various temperatures regions with an emphasis on optimising the various detector resolutions for specific temperatures. One resolution target is of about 10 eV at the energies range typically created in kaonic atoms experiments (soft x-ray energies). A following step will see the introduction of continuous, high-power, sub-Kelvin cooling which will bring the cryogenic basis for a high resolution spectrometer system to the market. The scientific goal of the project will produce an experimental set-up optimised for kaon-mass measurements performing high-resolution x-ray spectroscopy on a beam-line provided foreseeably by the J-PARC (Tokai, Japan) or DAΦNE (Frascati, Italy) facilities.

High-resolution metallic magnetic calorimeters for {beta}-spectroscopy on {sup 187}rhenium and position resolved X-ray spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Porst, Jan-Patrick

2011-02-01

This thesis describes the development of metallic magnetic calorimeters (MMCs) for high resolution spectroscopy. MMCs are energy dispersive particle detectors based on the calorimetric principle which are typically operated at temperatures below 100 mK. The detectors make use of a paramagnetic temperature sensor to transform the temperature rise upon the absorption of a particle in the detector into a measurable magnetic flux change in a dc-SQUID. The application of MMCs for neutrino mass measurements and their advantages with respect to other approaches are discussed. In view of this application the development of an MMC optimized for {beta}-endpoint spectroscopy on {sup 187}rhenium is presented. A fully micro-fabricated X-ray detector is characterized and performs close to design values. Furthermore, a new technique to more efficiently couple rhenium absorbers mechanically and thermally to the sensor was developed and successfully tested. By employing a metallic contact, signal rise times faster than 5 {mu}s could be observed with superconducting rhenium absorbers. In addition to the single pixel detectors, an alternative approach of reading out multiple pixels was developed in this work, too. Here, the individual absorbers have a different thermal coupling to only one temperature sensor resulting in a distribution of different pulse shapes. Straightforward position discrimination by means of rise time analysis is demonstrated for a four pixel MMC and a thermal model of the detector is provided. Unprecedented so far, an energy resolution of less than {delta}E{sub FWHM}<5 eV for 5.9 keV X-rays was achieved across all absorbers. (orig.)

High-resolution magnetic resonance imaging tracks changes in organ and tissue mass in obese and aging rats.

Science.gov (United States)

Tang, Haiying; Vasselli, Joseph R; Wu, Ed X; Boozer, Carol N; Gallagher, Dympna

2002-03-01

Magnetic resonance imaging (MRI) has the ability to discriminate between various soft tissues in vivo. Whole body, specific organ, total adipose tissue (TAT), intra-abdominal adipose tissue (IAAT), and skeletal muscle (SM) weights determined by MRI were compared with weights determined by dissection and chemical analysis in two studies with male Sprague-Dawley rats. A 4.2-T MRI machine acquired high-resolution, in vivo, longitudinal whole body images of rats as they developed obesity or aged. Weights of the whole body and specific tissues were determined using computer image analysis software, including semiautomatic segmentation algorithms for volume calculations. High correlations were found for body weight (r = 0.98), TAT (r = 0.99), and IAAT (r = 0.98) between MRI and dissection and chemical analyses. MRI estimated the weight of the brain, kidneys, and spleen with high accuracy (r > 0.9), but overestimated IAAT, SM, and liver volumes. No differences were detected in organ weights using MRI and dissection measurements. Longitudinal MRI measurements made during the development of obesity and aging accurately represented changes in organ and tissue mass.

Time lens for high-resolution neutron time-of-flight spectrometers

International Nuclear Information System (INIS)

Baumann, K.; Gaehler, R.; Grigoriev, P.; Kats, E.I.

2005-01-01

We examine in analytic and numeric ways the imaging effects of temporal neutron lenses created by traveling magnetic fields. For fields of parabolic shape we derive the imaging equations, investigate the time magnification, the evolution of the phase-space element, the gain factor, and the effect of finite beam size. The main aberration effects are calculated numerically. The system is technologically feasible and should convert neutron time-of-flight instruments from pinhole to imaging configuration in time, thus enhancing intensity and/or time resolution. Further fields of application for high-resolution spectrometry may be opened

High spatial resolution upgrade of the electron cyclotron emission radiometer for the DIII-D tokamak.

Science.gov (United States)

Truong, D D; Austin, M E

2014-11-01

The 40-channel DIII-D electron cyclotron emission (ECE) radiometer provides measurements of Te(r,t) at the tokamak midplane from optically thick, second harmonic X-mode emission over a frequency range of 83-130 GHz. The frequency spacing of the radiometer's channels results in a spatial resolution of ∼1-3 cm, depending on local magnetic field and electron temperature. A new high resolution subsystem has been added to the DIII-D ECE radiometer to make sub-centimeter (0.6-0.8 cm) resolution Te measurements. The high resolution subsystem branches off from the regular channels' IF bands and consists of a microwave switch to toggle between IF bands, a switched filter bank for frequency selectivity, an adjustable local oscillator and mixer for further frequency down-conversion, and a set of eight microwave filters in the 2-4 GHz range. Higher spatial resolution is achieved through the use of a narrower (200 MHz) filter bandwidth and closer spacing between the filters' center frequencies (250 MHz). This configuration allows for full coverage of the 83-130 GHz frequency range in 2 GHz bands. Depending on the local magnetic field, this translates into a "zoomed-in" analysis of a ∼2-4 cm radial region. Expected uses of these channels include mapping the spatial dependence of Alfven eigenmodes, geodesic acoustic modes, and externally applied magnetic perturbations. Initial Te measurements, which demonstrate that the desired resolution is achieved, are presented.

High spatial resolution soft-x-ray microscopy

Energy Technology Data Exchange (ETDEWEB)

Meyer-Ilse, W.; Medecki, H.; Brown, J.T. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)] [and others

1997-04-01

A new soft x-ray microscope (XM-1) with high spatial resolution has been constructed by the Center for X-ray Optics. It uses bending magnet radiation from beamline 6.1 at the Advanced Light Source, and is used in a variety of projects and applications in the life and physical sciences. Most of these projects are ongoing. The instrument uses zone plate lenses and achieves a resolution of 43 nm, measured over 10% to 90% intensity with a knife edge test sample. X-ray microscopy permits the imaging of relatively thick samples, up to 10 {mu}m thick, in water. XM-1 has an easy to use interface, that utilizes visible light microscopy to precisely position and focus the specimen. The authors describe applications of this device in the biological sciences, as well as in studying industrial applications including structured polymer samples.

Analysis strategies for high-resolution UHF-fMRI data.

Science.gov (United States)

Polimeni, Jonathan R; Renvall, Ville; Zaretskaya, Natalia; Fischl, Bruce

2018-03-01

Functional MRI (fMRI) benefits from both increased sensitivity and specificity with increasing magnetic field strength, making it a key application for Ultra-High Field (UHF) MRI scanners. Most UHF-fMRI studies utilize the dramatic increases in sensitivity and specificity to acquire high-resolution data reaching sub-millimeter scales, which enable new classes of experiments to probe the functional organization of the human brain. This review article surveys advanced data analysis strategies developed for high-resolution fMRI at UHF. These include strategies designed to mitigate distortion and artifacts associated with higher fields in ways that attempt to preserve spatial resolution of the fMRI data, as well as recently introduced analysis techniques that are enabled by these extremely high-resolution data. Particular focus is placed on anatomically-informed analyses, including cortical surface-based analysis, which are powerful techniques that can guide each step of the analysis from preprocessing to statistical analysis to interpretation and visualization. New intracortical analysis techniques for laminar and columnar fMRI are also reviewed and discussed. Prospects for single-subject individualized analyses are also presented and discussed. Altogether, there are both specific challenges and opportunities presented by UHF-fMRI, and the use of proper analysis strategies can help these valuable data reach their full potential. Copyright © 2017 Elsevier Inc. All rights reserved.

A High-Resolution Thermometer for the Range 0.75-1.0 K

Science.gov (United States)

Panek, J.; Nash, A.; Larson, M.; Mulders, N.

1999-01-01

We report on a new high-resolution thermometer (HRT) for use near the tricritical point in 3He-4He mixtures. It is based on an existing HRT design that uses a DC-SQUID to detect the magnetization of a paramagnetic sensing element.

High-Sensitivity Measurement of Density by Magnetic Levitation.

Science.gov (United States)

Nemiroski, Alex; Kumar, A A; Soh, Siowling; Harburg, Daniel V; Yu, Hai-Dong; Whitesides, George M

2016-03-01

This paper presents methods that use Magnetic Levitation (MagLev) to measure very small differences in density of solid diamagnetic objects suspended in a paramagnetic medium. Previous work in this field has shown that, while it is a convenient method, standard MagLev (i.e., where the direction of magnetization and gravitational force are parallel) cannot resolve differences in density mm) because (i) objects close in density prevent each other from reaching an equilibrium height due to hard contact and excluded volume, and (ii) using weaker magnets or reducing the magnetic susceptibility of the medium destabilizes the magnetic trap. The present work investigates the use of weak magnetic gradients parallel to the faces of the magnets as a means of increasing the sensitivity of MagLev without destabilization. Configuring the MagLev device in a rotated state (i.e., where the direction of magnetization and gravitational force are perpendicular) relative to the standard configuration enables simple measurements along the axes with the highest sensitivity to changes in density. Manipulating the distance of separation between the magnets or the lengths of the magnets (along the axis of measurement) enables the sensitivity to be tuned. These modifications enable an improvement in the resolution up to 100-fold over the standard configuration, and measurements with resolution down to 10(-6) g/cm(3). Three examples of characterizing the small differences in density among samples of materials having ostensibly indistinguishable densities-Nylon spheres, PMMA spheres, and drug spheres-demonstrate the applicability of rotated Maglev to measuring the density of small (0.1-1 mm) objects with high sensitivity. This capability will be useful in materials science, separations, and quality control of manufactured objects.

SOLARNET: a high resolution mission to complement the ILWS programme

Science.gov (United States)

Dame, L.; Clade, S.; Malherbe, J. M.

SOLARNET is a medium size high resolution solar physics mission proposed to CNES for a new start in 2006 and a possible launch in 2010. Partnerships with Germany, Belgium, China and India are under discussion. At the center of the SOLARNET mission is a 3-telescopes interferometer of 1 meter baseline capable to provide 50 times the best ever spatial resolution achieved in Space with previous, current or even planned solar missions: 20 mas - 20 km on the Sun in the FUV. The interferometer is associated to an on-axis subtractive double monochromator (imaging spectrograph) capable of high spectral (0.01 nm) and high temporal resolutions (50 ms) on a field of view of 40 arcsec and over the FUV and UV spectral domains (from 117.5 to 400 nm). This will allow to access process scales of magnetic reconnection, dissipation, emerging flux and much more, from the high chromosphere to the low corona with emphasis on the transition zone where the magnetic confinement is expected to be maximum. A whole new chapter of the physics of solar magnetic field structuring and evolution will be opened. The interferometer is complemented by several other instruments providing larger field of view and higher temperature (EUV-XUV coronal imaging) to define the context and extension of the solar phenomena. Helioseismology, a strong asset of SOHO, is also intended with both velocity and diameter measures, allowed by a non-eclipsing Sun synchronous orbit. The SOLARNET interferometer design results of an extensive laboratory demonstration program of interferometric imaging of extended objects. It started 10 years ago and culminates this year with the first interferometric observations (images) of the Sun at Meudon Observatory at the "Grand Siderostat de Foucault" with a complete 3 telescopes cophased interferometer representative of SOLARNET. We will review the scientific program of SOLARNET, describe the interferometer concept and design, present the first solar imaging results of the

Study of the performance of HPGe detectors operating in very high magnetic fields

International Nuclear Information System (INIS)

Agnello, M.; Botta, E.; Bressani, T.; Bruschi, M.; Bufalino, S.; De Napoli, M.; Feliciello, A.; Fontana, A.; Giacobbe, B.; Lavezzi, L.; Raciti, G.; Rapisarda, E.; Rotondi, A.; Sbarra, C.; Sfienti, C.; Zoccoli, A.

2009-01-01

A new generation of high-resolution hypernuclear γ-spectroscopy experiments using high-purity germanium (HPGe) detectors is presently designed for the FINUDA spectrometer at DAΦNE, the Frascati Φ-factory, and for PANDA, the p-p-bar hadron spectrometer at the future FAIR facility. In both spectrometers the HPGe detectors have to be operated in strong magnetic fields. In this paper we report on a series of measurements performed on a HPGe detector inserted in a magnetic field of intensity up to 2.5 T, the highest ever reached for operations with a HPGe, and with different orientations of the detector's axis with respect to field direction. A significant worsening of the energy resolution was found, but with a moderate loss of the efficiency. The most relevant features of the peak shapes, described by bi-Gaussian functions, are parametrized in terms of field intensity and energy: this allows to correct the spectra measured in magnetic field and to recover the energy resolution almost completely.

High-resolution 3T Magnetic Resonance Imaging of the Triangular Fibrocartilage Complex in Chinese Wrists: Correlation with Cross-sectional Anatomy.

Science.gov (United States)

Zhan, Hui-Li; Li, Wen-Ting; Bai, Rong-Jie; Wang, Nai-Li; Qian, Zhan-Hua; Ye, Wei; Yin, Yu-Ming

2017-04-05

The injury of the triangular fibrocartilage complex (TFCC) is a common cause of ulnar-sided wrist pain. The aim of this study was to investigate if the high-resolution 3T magnetic resonance imaging (MRI) could demonstrate the detailed complex anatomy of TFCC in Chinese. Fourteen Chinese cadaveric wrists (from four men and three women; age range at death from 30 to 60 years; mean age at 46 years) and forty healthy Chinese wrists (from 20 healthy volunteers, male/female: 10/10; age range from 21 to 53 years with a mean age of 32 years) in Beijing Jishuitan Hospital from March 2014 to March 2016 were included in this study. All cadavers and volunteers had magnetic resonance (MR) examination of the wrist with coronal T1-weighted and proton density-weighted imaging with fat suppression in three planes, respectively. MR arthrography (MRAr) was performed on one of the cadaveric wrists. Subsequently, all 14 cadaveric wrists were sliced into 2 mm thick slab with band saw (six in coronal plane, four in sagittal plane, and four in axial plane). The MRI features of normal TFCC were analyzed in these specimens and forty healthy wrists. Triangular fibrocartilage, the ulnar collateral ligament, and the meniscal homolog could be best observed on images in coronal plane. The palmar and dorsal radioulnar ligaments were best evaluated in transverse plane. The ulnotriquetral and ulnolunate ligaments were best visualized in sagittal plane. The latter two structures and the volar and dorsal capsules were better demonstrated on MRAr. High-resolution 3T MRI is capable to show the detailed complex anatomy of the TFCC and can provide valuable information for the clinical diagnosis in Chinese.

PEPSI, the High-Resolution Optical-IR Spectrograph for the LBT

Science.gov (United States)

Andersen, Michael; Strassmeier, Klaus; Hoffman, Axel; Woche, Manfred; Spano, Paolo

PEPSI is a high resolution fibre feed optical-IR polarimetric echelle spectrograph for the Large Binocular Telescope (LBT). PEPSI utilizes the two 8.4m LBT apertures to simultaneously record four polarization states at a resolution of 120.000. The extension of the coverage towards the IR is mainly motivated by the larger Zeeman splitting of IR lines, which would allow to study weaker/fainter magnetic structures on stars. The two optical arms, which also have an integral light mode with R up to 300.000, are under construction, while the IR arm is being designed.

High resolution imaging of tunnels by magnetic resonance neurography

Energy Technology Data Exchange (ETDEWEB)

Subhawong, Ty K.; Thawait, Shrey K.; Machado, Antonio J.; Carrino, John A.; Chhabra, Avneesh [Johns Hopkins Hospital, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Wang, Kenneth C. [Baltimore VA Medical Center, Department of Radiology, Baltimore, MD (United States); Williams, Eric H. [Dellon Institute for Peripheral Nerve Surgery, Towson, MD (United States); Hashemi, Shahreyar Shar [Johns Hopkins Hospital, Division of Plastic and Reconstructive Surgery, Baltimore, MD (United States)

2012-01-15

Peripheral nerves often traverse confined fibro-osseous and fibro-muscular tunnels in the extremities, where they are particularly vulnerable to entrapment and compressive neuropathy. This gives rise to various tunnel syndromes, characterized by distinct patterns of muscular weakness and sensory deficits. This article focuses on several upper and lower extremity tunnels, in which direct visualization of the normal and abnormal nerve in question is possible with high resolution 3T MR neurography (MRN). MRN can also serve as a useful adjunct to clinical and electrophysiologic exams by discriminating adhesive lesions (perineural scar) from compressive lesions (such as tumor, ganglion, hypertrophic callous, or anomalous muscles) responsible for symptoms, thereby guiding appropriate treatment. (orig.)

High resolution imaging of tunnels by magnetic resonance neurography

International Nuclear Information System (INIS)

Subhawong, Ty K.; Thawait, Shrey K.; Machado, Antonio J.; Carrino, John A.; Chhabra, Avneesh; Wang, Kenneth C.; Williams, Eric H.; Hashemi, Shahreyar Shar

2012-01-01

Peripheral nerves often traverse confined fibro-osseous and fibro-muscular tunnels in the extremities, where they are particularly vulnerable to entrapment and compressive neuropathy. This gives rise to various tunnel syndromes, characterized by distinct patterns of muscular weakness and sensory deficits. This article focuses on several upper and lower extremity tunnels, in which direct visualization of the normal and abnormal nerve in question is possible with high resolution 3T MR neurography (MRN). MRN can also serve as a useful adjunct to clinical and electrophysiologic exams by discriminating adhesive lesions (perineural scar) from compressive lesions (such as tumor, ganglion, hypertrophic callous, or anomalous muscles) responsible for symptoms, thereby guiding appropriate treatment. (orig.)

High spatial resolution upgrade of the electron cyclotron emission radiometer for the DIII-D tokamak

Energy Technology Data Exchange (ETDEWEB)

Truong, D. D., E-mail: dtruong@wisc.edu [Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Austin, M. E. [Institute for Fusion Studies, University of Texas, Austin, Texas, 78712 (United States)

2014-11-15

The 40-channel DIII-D electron cyclotron emission (ECE) radiometer provides measurements of T{sub e}(r,t) at the tokamak midplane from optically thick, second harmonic X-mode emission over a frequency range of 83–130 GHz. The frequency spacing of the radiometer's channels results in a spatial resolution of ∼1–3 cm, depending on local magnetic field and electron temperature. A new high resolution subsystem has been added to the DIII-D ECE radiometer to make sub-centimeter (0.6–0.8 cm) resolution T{sub e} measurements. The high resolution subsystem branches off from the regular channels’ IF bands and consists of a microwave switch to toggle between IF bands, a switched filter bank for frequency selectivity, an adjustable local oscillator and mixer for further frequency down-conversion, and a set of eight microwave filters in the 2–4 GHz range. Higher spatial resolution is achieved through the use of a narrower (200 MHz) filter bandwidth and closer spacing between the filters’ center frequencies (250 MHz). This configuration allows for full coverage of the 83–130 GHz frequency range in 2 GHz bands. Depending on the local magnetic field, this translates into a “zoomed-in” analysis of a ∼2–4 cm radial region. Expected uses of these channels include mapping the spatial dependence of Alfven eigenmodes, geodesic acoustic modes, and externally applied magnetic perturbations. Initial T{sub e} measurements, which demonstrate that the desired resolution is achieved, are presented.

Detection of tannins in modern and fossil barks and in plant residues by high-resolution solid-state /sup 13/C nuclear magnetic resonance

Energy Technology Data Exchange (ETDEWEB)

Wilson, M A; Hatcher, P G

1988-01-01

Bark samples isolated from brown coal deposits in Victoria, Australia, and buried wood from Rhizophora mangle have been studied by high-resolution solid-state nuclear magnetic resonance (NMR) techniques. Dipolar dephasing /sup 13/C NMR appears to be a useful method of detecting the presence of tannins in geochemical samples including barks, buried woods, peats and leaf litter. It is shown that tannins are selectively preserved in bark during coalification to the brown coal stage. 28 refs., 9 figs., 1 tab.

A high-resolution Fourier Transform Spectrometer for planetary spectroscopy

Science.gov (United States)

Cruikshank, D. P.; Sinton, W. M.

1973-01-01

The employment of a high-resolution Fourier Transform Spectrometer (FTS) is described for planetary and other astronomical spectroscopy in conjunction with the 88-inch telescope at Mauna Kea Observatory. The FTS system is designed for a broad range of uses, including double-beam laboratory spectroscopy, infrared gas chromatography, and nuclear magnetic resonance spectroscopy. The data system is well-suited to astronomical applications because of its great speed in acquiring and transforming data, and because of the enormous storage capability of the magnetic tape unit supplied with the system. The basic instrument is outlined 2nd some of the initial results from the first attempted use on the Mauna Kea 88-inch telescope are reported.

High-resolution inelastic electron scattering on 208Pb at 50 and 63.5 MeV and fragmentation of the magnetic quadrupole strength

International Nuclear Information System (INIS)

Knuepfer, W.; Frey, R.; Richter, A.; Schwierczinski, A.; Spamer, E.; Titze, O.

1977-12-01

High-resolution inelastic electron scattering (FWHM approximately equal to 33 keV) with 50 MeV and 63.5 MeV electrons on 208 Pb has been used to study magnetic excitations between Esub(x) = 6 MeV and 8 MeV. Angular distributions were analyzed in terms of the DWBA with RPA wave functions. Eight Isup(π) = 2- states carrying a total strength ΣB(M2) = 8500 μ 2 sub(K) fm 2 have been found. The strong fragmentation is in qualitative agreement with theoretical predictions. (orig.) [de

Functional magnetic resonance imaging with ultra-high fields

International Nuclear Information System (INIS)

Windischberger, C.; Schoepf, V.; Sladky, R.; Moser, E.; Fischmeister, F.P.S.

2010-01-01

Functional magnetic resonance imaging (fMRI) is currently the primary method for non-invasive functional localization in the brain. With the emergence of MR systems with field strengths of 4 Tesla and above, neuronal activation may be studied with unprecedented accuracy. In this article we present different approaches to use the improved sensitivity and specificity for expanding current fMRT resolution limits in space and time based on several 7 Tesla studies. In addition to the challenges that arise with ultra-high magnetic fields possible solutions will be discussed. (orig.) [de

High-resolution Lyman-alpha filtergrams of the sun

Science.gov (United States)

Bonnet, R. M.; Decaudin, M.; Bruner, E. C., Jr.; Acton, L. W.; Brown, W. A.

1980-01-01

The results of an experiment, conducted jointly by the Lockheed Palo Alto Research Laboratory and the Laboratoire de Physique Stellaire et Planetaire du CNRS, which investigated the transition-region plasma and the geometry of coronal active regions, in relation to models of the high-temperature layers, are presented. A Black Brant rocket was used to obtain 1-arc sec resolution L-alpha pictures of the sun, which revealed small scale features not seen previously at this wavelength, that delineate the geometry of the magnetic field in the chromosphere and in the corona. It is concluded that these observations might provide a new way of observing the upper chromosphere and corona, and that they provide direct evidence of the inhomogeneous character of the chromosphere and of the dominant role of the magnetic field

Toward high-resolution NMR spectroscopy of microscopic liquid samples

Energy Technology Data Exchange (ETDEWEB)

Butler, Mark C.; Mehta, Hardeep S.; Chen, Ying; Reardon, Patrick N.; Renslow, Ryan S.; Khbeis, Michael; Irish, Duane; Mueller, Karl T.

2017-01-01

A longstanding limitation of high-resolution NMR spectroscopy is the requirement for samples to have macroscopic dimensions. Commercial probes, for example, are designed for volumes of at least 5 mL, in spite of decades of work directed toward the goal of miniaturization. Progress in miniaturizing inductive detectors has been limited by a perceived need to meet two technical requirements: (1) minimal separation between the sample and the detector, which is essential for sensitivity, and (2) near-perfect magnetic-field homogeneity at the sample, which is typically needed for spectral resolution. The first of these requirements is real, but the second can be relaxed, as we demonstrate here. By using pulse sequences that yield high-resolution spectra in an inhomogeneous field, we eliminate the need for near-perfect field homogeneity and the accompanying requirement for susceptibility matching of microfabricated detector components. With this requirement removed, typical imperfections in microfabricated components can be tolerated, and detector dimensions can be matched to those of the sample, even for samples of volume << 5 uL. Pulse sequences that are robust to field inhomogeneity thus enable small-volume detection with optimal sensitivity. We illustrate the potential of this approach to miniaturization by presenting spectra acquired with a flat-wire detector that can easily be scaled to subnanoliter volumes. In particular, we report high-resolution NMR spectroscopy of an alanine sample of volume 500 pL.

Nanomagnets with high shape anisotropy and strong crystalline anisotropy: perspectives on magnetic force microscopy

International Nuclear Information System (INIS)

Campanella, H; Llobet, J; Esteve, J; Plaza, J A; Jaafar, M; Vázquez, M; Asenjo, A; Del Real, R P

2011-01-01

We report on a new approach for magnetic imaging, highly sensitive even in the presence of external, strong magnetic fields. Based on FIB-assisted fabricated high-aspect-ratio rare-earth nanomagnets, we produce groundbreaking magnetic force tips with hard magnetic character where we combine a high aspect ratio (shape anisotropy) together with strong crystalline anisotropy (rare-earth-based alloys). Rare-earth hard nanomagnets are then FIB-integrated to silicon microcantilevers as highly sharpened tips for high-field magnetic imaging applications. Force resolution and domain reversing and recovery capabilities are at least one order of magnitude better than for conventional magnetic tips. This work opens new, pioneering research fields on the surface magnetization process of nanostructures based either on relatively hard magnetic materials—used in magnetic storage media—or on materials like superparamagnetic particles, ferro/antiferromagnetic structures or paramagnetic materials.

Photoionization of H2O at high resolution

International Nuclear Information System (INIS)

Dehmer, P.M.; Chupka, W.A.

1978-01-01

The relative photoionization cross sections for the formation of H 2 O + , OH + , and H + from H 2 O were measured at high wavelength resolution using a 3-meter photoionization mass spectrometer equipped with a quadrupole mass flter and a 1-meter photoionization mass spectrometer equipped with a 12-inch radius, 60 0 sector magnetic mass spectrometer. Discrete structure in the parent ion photoionization efficiency curve is interpreted in terms of Rydberg series converging to excited states of the H 2 O + ion. 9 references

Magnetic and Superconducting Materials at High Pressures

Energy Technology Data Exchange (ETDEWEB)

Struzhkin, Viktor V. [Carnegie Inst. of Washington, Washington, DC (United States)

2015-03-24

transitions from magnetic to nonmagnetic phases in a broad pressure-temperature range; using X-ray methods including the newly developed RIXS high-pressure technique to explore pressure-tuned electronic excitations in strongly correlated 3d-materials; and advancing transport and magnetic techniques for measurements on small samples at very high pressures in a wide temperature range, with the application of focused ion beam technology and photolithography tailored to the design of microcircuits down to a nanoscale size, thus expanding the horizon in the search for novel physical phenomena at ultrahigh pressures. Apply new optical magnetic sensing techniques with NV- centers in diamond to detect superconductivity and magnetic transitions with unprecedented spatial resolution.

Functional magnetic resonance microscopy at single-cell resolution in Aplysia californica

Science.gov (United States)

Radecki, Guillaume; Nargeot, Romuald; Jelescu, Ileana Ozana; Le Bihan, Denis; Ciobanu, Luisa

2014-01-01

In this work, we show the feasibility of performing functional MRI studies with single-cell resolution. At ultrahigh magnetic field, manganese-enhanced magnetic resonance microscopy allows the identification of most motor neurons in the buccal network of Aplysia at low, nontoxic Mn2+ concentrations. We establish that Mn2+ accumulates intracellularly on injection into the living Aplysia and that its concentration increases when the animals are presented with a sensory stimulus. We also show that we can distinguish between neuronal activities elicited by different types of stimuli. This method opens up a new avenue into probing the functional organization and plasticity of neuronal networks involved in goal-directed behaviors with single-cell resolution. PMID:24872449

High-resolution PET [Positron Emission Tomography] for Medical Science Studies

Science.gov (United States)

Budinger, T. F.; Derenzo, S. E.; Huesman, R. H.; Jagust, W. J.; Valk, P. E.

1989-09-01

One of the unexpected fruits of basic physics research and the computer revolution is the noninvasive imaging power available to today's physician. Technologies that were strictly the province of research scientists only a decade or two ago now serve as the foundations for such standard diagnostic tools as x-ray computer tomography (CT), magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), ultrasound, single photon emission computed tomography (SPECT), and positron emission tomography (PET). Furthermore, prompted by the needs of both the practicing physician and the clinical researcher, efforts to improve these technologies continue. This booklet endeavors to describe the advantages of achieving high resolution in PET imaging.

Complementary analyses of hollow cylindrical unioriented permanent magnet (HCM) with high permeability external layer

Science.gov (United States)

Lobo, Carlos M. S.; Tosin, Giancarlo; Baader, Johann E.; Colnago, Luiz A.

2017-10-01

In this article, several studies based on analytical expressions and computational simulations on Hollow Cylindrical Magnets with an external soft ferromagnetic material (HCM magnets) are presented. Electromagnetic configurations, as well as permanent-magnet-based structures, are studied in terms of magnetic field strength and homogeneity. Permanent-magnet-based structures are further analyzed in terms of the anisotropy of the magnetic permeability. It was found that the HCM magnets produce a highly homogeneous magnetic field as long as the magnetic material is isotropic. The dependency of the magnetic field strength and homogeneity in terms of the anisotropy of the magnetic permeability is also explored here. These magnets can potentially be used in medium-resolution NMR spectrometers and high-field NMR spectrometers.

Helium temperature measurements in a hot filament magnetic mirror plasma using high resolution Doppler spectroscopy

Science.gov (United States)

Knott, S.; McCarthy, P. J.; Ruth, A. A.

2016-09-01

Langmuir probe and spectroscopic diagnostics are used to routinely measure electron temperature and density over a wide operating range in a reconfigured Double Plasma device at University College Cork, Ireland. The helium plasma, generated through thermionic emission from a negatively biased tungsten filament, is confined by an axisymmetric magnetic mirror configuration using two stacks of NdFeB permanent magnets, each of length 20 cm and diameter 3 cm placed just outside the 15 mm water cooling jacket enclosing a cylindrical vacuum vessel of internal diameter 25 cm. Plasma light is analysed using a Fourier Transform-type Bruker spectrometer with a highest achievable resolution of 0.08 cm-1 . In the present work, the conventional assumption of room temperature ions in the analysis of Langmuir probe data from low temperature plasmas is examined critically using Doppler spectroscopy of the 468.6 nm He II line. Results for ion temperatures obtained from spectroscopic data for a variety of engineering parameters (discharge voltage, gas pressure and plasma current) will be presented.

High resolution magnetic force microscopy: instrumentation and application for recording media

NARCIS (Netherlands)

Porthun, Steffen; Porthun, S.

This thesis describes aspects of the use of magnetic force microscopy for the study of magnetic recording media. The maximum achievable storage density in magnetic recording is limited by the magnetic reversal behaviour of the medium and by the stability of the written information. The shape and

Velocity-space observation regions of high-resolution two-step reaction gamma-ray spectroscopy

DEFF Research Database (Denmark)

Salewski, Mirko; Nocente, M.; Gorini, G.

2015-01-01

High-resolution γ-ray spectroscopy (GRS) measurements resolve spectral shapes of Dopplerbroadened γ-rays. We calculate weight functions describing velocity-space sensitivities of any two-step reaction GRS measurements in magnetized plasmas using the resonant nuclear reaction 9Be(α, nγ)12C...

In vivo High Angular Resolution Diffusion-Weighted Imaging of Mouse Brain at 16.4 Tesla

OpenAIRE

Alomair, Othman I.; Brereton, Ian M.; Smith, Maree T.; Galloway, Graham J.; Kurniawan, Nyoman D.

2015-01-01

Magnetic Resonance Imaging (MRI) of the rodent brain at ultra-high magnetic fields (> 9.4 Tesla) offers a higher signal-to-noise ratio that can be exploited to reduce image acquisition time or provide higher spatial resolution. However, significant challenges are presented due to a combination of longer T 1 and shorter T 2/T2* relaxation times and increased sensitivity to magnetic susceptibility resulting in severe local-field inhomogeneity artefacts from air pockets and bone/brain interfaces...

Femtosecond laser spectroscopy of spins: Magnetization dynamics in thin magnetic films with spatio-temporal resolution

International Nuclear Information System (INIS)

Carpene, E.; Mancini, E.; Dallera, C.; Puppin, E.; De Silvestri, S.

2010-01-01

Based on the Magneto-Optical Kerr Effect (MOKE), we have developed an experimental set-up that allows us to fully characterize the magnetization dynamics in thin magnetic films by measuring all three real space components of the magnetization vector M. By means of the pump-probe technique it is possible to extract the time dependence of each individual projection with sub-picosecond resolution. This method has been exploited to investigate the temporal evolution of the magnetization (modulus and orientation) induced by an ultrashort laser pulse in thin epitaxial iron films. According to our results, we deduced that the initial, sub-picosecond demagnetization is established at the electronic level through electron-magnon excitations. The subsequent dynamics is characterized by a precessional motion on the 100 ps time scale, around an effective, time-dependent magnetic field. Following the full dynamics of M, the temporal evolution of the magneto-crystalline anisotropy constant can be unambiguously determined, providing the experimental evidence that the precession is triggered by the rapid, optically-induced misalignment between the magnetization vector and the effective magnetic field. These results suggest a possible pathway toward the ultrarapid switching of the magnetization.

High Resolution Marine Magnetic Survey of Shallow Water Littoral Area

OpenAIRE

Jacob Sharvit; Nizan Salomonski; Roger Alimi; Hovav Zafrir; Tsuriel Ram Cohen; Boris Ginzburg; Eyal Weiss

2007-01-01

The purpose of this paper is to present a system developed for detection andaccurate mapping of ferro-metallic objects buried below the seabed in shallow waters. Thesystem comprises a precise magnetic gradiometer and navigation subsystem, both installedon a non-magnetic catamaran towed by a low-magnetic interfering boat. In addition wepresent the results of a marine survey of a near-shore area in the vicinity of Atlit, a townsituated on the Mediterranean coast of Israel, about 15 km south of ...

Novel Gd nanoparticles enhance vascular contrast for high-resolution magnetic resonance imaging.

Directory of Open Access Journals (Sweden)

Tot Bui

2010-09-01

Full Text Available Gadolinium (Gd, with its 7 unpaired electrons in 4f orbitals that provide a very large magnetic moment, is proven to be among the best agents for contrast enhanced MRI. Unfortunately, the most potent MR contrast agent based on Gd requires relatively high doses of Gd. The Gd-chelated to diethylene-triamine-penta-acetic acid (DTPA, or other derivatives (at 0.1 mmole/kg recommended dose, distribute broadly into tissues and clear through the kidney. These contrast agents carry the risk of Nephrogenic Systemic Fibrosis (NSF, particularly in kidney impaired subjects. Thus, Gd contrast agents that produce higher resolution images using a much lower Gd dose could address both imaging sensitivity and Gd safety.To determine whether a biocompatible lipid nanoparticle with surface bound Gd can improve MRI contrast sensitivity, we constructed Gd-lipid nanoparticles (Gd-LNP containing lipid bound DTPA and Gd. The Gd-LNP were intravenously administered to rats and MR images collected. We found that Gd in Gd-LNP produced a greater than 33-fold higher longitudinal (T(1 relaxivity, r(1, constant than the current FDA approved Gd-chelated contrast agents. Intravenous administration of these Gd-LNP at only 3% of the recommended clinical Gd dose produced MRI signal-to-noise ratios of greater than 300 in all vasculatures. Unlike current Gd contrast agents, these Gd-LNP stably retained Gd in normal vasculature, and are eliminated predominately through the biliary, instead of the renal system. Gd-LNP did not appear to accumulate in the liver or kidney, and was eliminated completely within 24 hrs.The novel Gd-nanoparticles provide high quality contrast enhanced vascular MRI at 97% reduced dose of Gd and do not rely on renal clearance. This new agent is likely to be suitable for patients exhibiting varying degrees of renal impairment. The simple and adaptive nanoparticle design could accommodate ligand or receptor coating for drug delivery optimization and in vivo drug

Complementary analyses of hollow cylindrical unioriented permanent magnet (HCM) with high permeability external layer.

Science.gov (United States)

Lobo, Carlos M S; Tosin, Giancarlo; Baader, Johann E; Colnago, Luiz A

2017-10-01

In this article, several studies based on analytical expressions and computational simulations on Hollow Cylindrical Magnets with an external soft ferromagnetic material (HCM magnets) are presented. Electromagnetic configurations, as well as permanent-magnet-based structures, are studied in terms of magnetic field strength and homogeneity. Permanent-magnet-based structures are further analyzed in terms of the anisotropy of the magnetic permeability. It was found that the HCM magnets produce a highly homogeneous magnetic field as long as the magnetic material is isotropic. The dependency of the magnetic field strength and homogeneity in terms of the anisotropy of the magnetic permeability is also explored here. These magnets can potentially be used in medium-resolution NMR spectrometers and high-field NMR spectrometers. Copyright © 2017 Elsevier Inc. All rights reserved.

High Resolution Marine Magnetic Survey of Shallow Water Littoral Area

OpenAIRE

Weiss, Eyal; Ginzburg, Boris; Cohen, Tsuriel Ram; Zafrir, Hovav; Alimi, Roger; Salomonski, Nizan; Sharvit, Jacob

2007-01-01

The purpose of this paper is to present a system developed for detection and accurate mapping of ferro-metallic objects buried below the seabed in shallow waters. The system comprises a precise magnetic gradiometer and navigation subsystem, both installed on a non-magnetic catamaran towed by a low-magnetic interfering boat. In addition we present the results of a marine survey of a near-shore area in the vicinity of Atlit, a town situated on the Mediterranean coast of Israel, about 15 km sout...

Fiber optic quench detection via optimized Rayleigh Scattering in high-field YBCO accelerator magnets

Energy Technology Data Exchange (ETDEWEB)

Flanagan, Gene [North Carolina State Univ., Raleigh, NC (United States)

2016-02-17

Yttrium barium copper oxide (YBCO) coated conductors are known for their ability to operate in the superconducting state at relatively high temperatures, even above the boiling point of liquid nitrogen (77 K). When these same conductors are operated at lower temperatures, they are able to operate in much higher magnetic fields than traditional superconductors like NiTi or Nb₃Sn. Thus, YBCO superconducting magnets are one of the primary options for generating the high magnetic fields needed for future high energy physics devices. Due to slow quench propagation, quench detection remains one of the primary limitations to YBCO magnets. Fiber optic sensing, based upon Rayleigh scattering, has the potential for spatial resolution approaching the wavelength of light, or very fast temporal resolution at low spatial resolution, and a continuum of combinations in between. This project has studied, theoretically and experimentally, YBCO magnets and Rayleigh scattering quench detection systems to demonstrate feasibility of the systems for YBCO quench protection systems. Under this grant an experimentally validated 3D quench propagation model was used to accurately define the acceptable range of spatial and temporal resolutions for effective quench detection in YBCO magnets and to evaluate present-day and potentially improved YBCO conductors. The data volume and speed requirements for quench detection via Rayleigh scattering required the development of a high performance fiber optic based quench detection/data acquisition system and its integration with an existing voltage tap/thermo-couple based system. In this project, optical fibers are tightly co-wound into YBCO magnet coils, with the fiber on top of the conductor as turn-to-turn insulation. Local changes in the temperature or strain of the conductor are sensed by the optical fiber, which is in close thermal and mechanical contact with the conductor. Intrinsic imperfections in the fiber reflect Rayleigh

Resolution limit of probe-forming systems with magnetic quadrupole lens triplets and quadruplets

International Nuclear Information System (INIS)

Ponomarev, A.G.; Melnik, K.I.; Miroshnichenko, V.I.; Storizhko, V.E.; Sulkio-Cleff, B.

2003-01-01

Over the past decade, in MeV ion beam microanalysis efforts to achieve a spatial resolution better than 0.1 μm with a beam current of ∼100 pA have been connected with microprobes of new generation where the probe is formed by means of separated magnetic quadrupole lens structures . However, as was pointed out in , no dramatic improvements in spatial resolution have been produced so far. For better understanding of the situation the authors carried out theoretical studies of multiparameter sets of probe-forming systems based on separated triplets and quadruplets of magnetic quadrupole lenses. Comparisons were made between the highest current values attained at different systems for a given beam spot size. The maximum parasitic sextupole and octupole field components were found whose contributions to spot broadening are tolerable. It is shown that the use of modern electrostatic accelerators and precision magnetic quadrupole lenses makes it possible to eliminate the effect of chromatic aberrations and second- and third-order parasitic aberrations resulting from distortions of the quadrupole lens symmetry. Therefore probe-forming systems with triplets and quadruplets of magnetic quadrupole lenses have a lower theoretical spatial resolution limit which is restricted mainly by intrinsic spherical third-order aberrations in state-of-the-art microprobes

High Resolution Marine Magnetic Survey of Shallow Water Littoral Area

Science.gov (United States)

Ginzburg, Boris; Cohen, Tsuriel Ram; Zafrir, Hovav; Alimi, Roger; Salomonski, Nizan; Sharvit, Jacob

2007-01-01

The purpose of this paper is to present a system developed for detection and accurate mapping of ferro-metallic objects buried below the seabed in shallow waters. The system comprises a precise magnetic gradiometer and navigation subsystem, both installed on a non-magnetic catamaran towed by a low-magnetic interfering boat. In addition we present the results of a marine survey of a near-shore area in the vicinity of Atlit, a town situated on the Mediterranean coast of Israel, about 15 km south of Haifa. The primary purpose of the survey was to search for a Harvard airplane that crashed into the sea in 1960. A magnetic map of the survey area (3.5 km2 on a 0.5 m grid) was created revealing the anomalies at sub-meter accuracy. For each investigated target location a corresponding ferro-metallic item was dug out, one of which turned to be very similar to a part of the crashed airplane. The accuracy of location was confirmed by matching the position of the actual dug artifacts with the magnetic map within a range of ± 1 m, in a water depth of 9 m. PMID:28903191

High Resolution Marine Magnetic Survey of Shallow Water Littoral Area

Directory of Open Access Journals (Sweden)

Jacob Sharvit

2007-09-01

Full Text Available The purpose of this paper is to present a system developed for detection andaccurate mapping of ferro-metallic objects buried below the seabed in shallow waters. Thesystem comprises a precise magnetic gradiometer and navigation subsystem, both installedon a non-magnetic catamaran towed by a low-magnetic interfering boat. In addition wepresent the results of a marine survey of a near-shore area in the vicinity of Atlit, a townsituated on the Mediterranean coast of Israel, about 15 km south of Haifa. The primarypurpose of the survey was to search for a Harvard airplane that crashed into the sea in 1960.A magnetic map of the survey area (3.5 km2 on a 0.5 m grid was created revealing theanomalies at sub-meter accuracy. For each investigated target location a correspondingferro-metallic item was dug out, one of which turned to be very similar to a part of thecrashed airplane. The accuracy of location was confirmed by matching the position of theactual dug artifacts with the magnetic map within a range of ± 1 m, in a water depth of 9 m.

High-resolution MRI predicts steroid injection response in carpal tunnel syndrome patients

Energy Technology Data Exchange (ETDEWEB)

Aoki, Takatoshi; Oki, Hodaka; Kinoshita, Shunsuke; Yamashita, Yoshiko; Takahashi, Hiroyuki; Hayashida, Yoshiko; Korogi, Yukunori [University of Occupational and Environmental Health School of Medicine, Department of Radiology, Kitakyushu (Japan); Oshige, Takahisa; Sakai, Akinori [University of Occupational and Environmental Health School of Medicine, Department of Orthopaedic Surgery, Kitakyushu (Japan); Matsuyama, Atsushi; Hisaoka, Masanori [University of Occupational and Environmental Health School of Medicine, Department of Pathology and Oncology, Kitakyushu (Japan)

2014-03-15

To correlate median nerve T2 signal and shape at the carpal tunnel with steroid injection (SI) response in carpal tunnel syndrome (CTS) patients. One hundred and sixty-three CTS wrists of 92 consecutive patients who were scheduled to undergo SI were prospectively evaluated with 3-T magnetic resonance imaging (MRI) and a nerve conduction study. All patients underwent axial high-resolution T2-weighted MRI (in-plane resolution of 0.25 x 0.25 mm). The CTS wrists were classified into three groups according to the nerve T2 signal and the flattening ratio at the hook of hamate level: group 1, high and oval; group 2, high and flat; group 3, low and flat. Clinical response to SI was evaluated at 6 months after injection. One hundred and thirteen of the 163 wrists (69.3 %) responded well to SI. The percentage of improvement was 81.7 % (49/60) in group 1, 69.9 % (51/73) in group 2, and 43.3 % (13/30) in group 3 (P < 0.01). On stepwise logistic regression analysis high-resolution MRI was the only significant independent factor for SI response in CTS patients (P < 0.01). High-resolution MRI correlates well with SI response in CTS patients and seems useful for predicting SI response. (orig.)

High resolution T{sub 2}{sup *}-weighted magnetic resonance imaging at 3 Tesla using PROPELLER-EPI

Energy Technology Data Exchange (ETDEWEB)

Kraemer, Martin; Reichenbach, Juergen R. [Jena University Hospital (Germany). Medical Physics Group

2014-09-01

We report the application of PROPELLER-EPI for high resolution T{sub 2}{sup *}-weighted imaging with sub-millimeter in-plane resolution on a clinical 3 Tesla scanner. Periodically rotated blades of a long-axis PROPELLER-EPI sequence were acquired with fast gradient echo readout and acquisition matrix of 320 x 50 per blade. Images were reconstructed by using 2D-gridding, phase and geometric distortion correction and compensation of resonance frequency drifts that occurred during extended measurements. To characterize these resonance frequency offsets, short FID calibration measurements were added to the PROPELLER-EPI sequence. Functional PROPELLER-EPI was performed with volunteers using a simple block design of right handed finger tapping. Results indicate that PROPELLER-EPI can be employed for fast, high resolution T{sub 2}{sup *}-weighted imaging provided geometric distortions and possible resonance frequency drifts are properly corrected. Even small resonance frequency drifts below 10 Hz as well as non-corrected geometric distortions degraded image quality substantially. In the initial fMRI experiment image quality and signal-to-noise ratio was sufficient for obtaining high resolution functional activation maps. (orig.)

Wavelength dependence of the magnetic resolution of the magneto-optical near-field scanning tunneling microscope

NARCIS (Netherlands)

Schad, R.; Jordan, S.M.; Stoelinga, M.J.P.; Prins, M.W.J.; Groeneveld, R.H.M.; Kempen, van H.; Kesteren, van H.W.

1998-01-01

A magneto-optical near-field scanning tunneling microscope is used to image the prewritten magnetic domain structure of a Pt/Co multilayer. A semiconducting tip acts as a local photodetector to measure the magnetic circular dichroism signal coming from the magnetic sample. The resolution of the

Metabolite-cycled density-weighted concentric rings k-space trajectory (DW-CRT) enables high-resolution 1 H magnetic resonance spectroscopic imaging at 3-Tesla.

Science.gov (United States)

Steel, Adam; Chiew, Mark; Jezzard, Peter; Voets, Natalie L; Plaha, Puneet; Thomas, Michael Albert; Stagg, Charlotte J; Emir, Uzay E

2018-05-17

Magnetic resonance spectroscopic imaging (MRSI) is a promising technique in both experimental and clinical settings. However, to date, MRSI has been hampered by prohibitively long acquisition times and artifacts caused by subject motion and hardware-related frequency drift. In the present study, we demonstrate that density weighted concentric ring trajectory (DW-CRT) k-space sampling in combination with semi-LASER excitation and metabolite-cycling enables high-resolution MRSI data to be rapidly acquired at 3 Tesla. Single-slice full-intensity MRSI data (short echo time (TE) semi-LASER TE = 32 ms) were acquired from 6 healthy volunteers with an in-plane resolution of 5 × 5 mm in 13 min 30 sec using this approach. Using LCModel analysis, we found that the acquired spectra allowed for the mapping of total N-acetylaspartate (median Cramer-Rao Lower Bound [CRLB] = 3%), glutamate+glutamine (8%), and glutathione (13%). In addition, we demonstrate potential clinical utility of this technique by optimizing the TE to detect 2-hydroxyglutarate (long TE semi-LASER, TE = 110 ms), to produce relevant high-resolution metabolite maps of grade III IDH-mutant oligodendroglioma in a single patient. This study demonstrates the potential utility of MRSI in the clinical setting at 3 Tesla.

SQUID-detected magnetic resonance imaging in microtesla magnetic fields

International Nuclear Information System (INIS)

McDermott, Robert; Kelso, Nathan; Lee, SeungKyun; Moessle, Michael; Mueck, Michael; Myers, Whittier; Haken, Bernard ten; Seton, H.C.; Trabesinger, Andreas H.; Pines, Alex; Clarke, John

2003-01-01

We describe studies of nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) of liquid samples at room temperature in microtesla magnetic fields. The nuclear spins are prepolarized in a strong transient field. The magnetic signals generated by the precessing spins, which range in frequency from tens of Hz to several kHz, are detected by a low-transition temperature dc SQUID (Superconducting QUantum Interference Device) coupled to an untuned, superconducting flux transformer configured as an axial gradiometer. The combination of prepolarization and frequency-independent detector sensitivity results in a high signal-to-noise ratio and high spectral resolution (∼1 Hz) even in grossly inhomogeneous magnetic fields. In the NMR experiments, the high spectral resolution enables us to detect the 10-Hz splitting of the spectrum of protons due to their scalar coupling to a 31P nucleus. Furthermore, the broadband detection scheme combined with a non-resonant field-reversal spin echo allows the simultaneous observation of signals from protons and 31P nuclei, even though their NMR resonance frequencies differ by a factor of 2.5. We extend our methodology to MRI in microtesla fields, where the high spectral resolution translates into high spatial resolution. We demonstrate two-dimensional images of a mineral oil phantom and slices of peppers, with a spatial resolution of about 1 mm. We also image an intact pepper using slice selection, again with 1-mm resolution. In further experiments we demonstrate T1-contrast imaging of a water phantom, some parts of which were doped with a paramagnetic salt to reduce the longitudinal relaxation time T1. Possible applications of this MRI technique include screening for tumors and integration with existing multichannel SQUID systems for brain imaging

Ultra-high resolution protein crystallography

International Nuclear Information System (INIS)

Takeda, Kazuki; Hirano, Yu; Miki, Kunio

2010-01-01

Many protein structures have been determined by X-ray crystallography and deposited with the Protein Data Bank. However, these structures at usual resolution (1.5< d<3.0 A) are insufficient in their precision and quantity for elucidating the molecular mechanism of protein functions directly from structural information. Several studies at ultra-high resolution (d<0.8 A) have been performed with synchrotron radiation in the last decade. The highest resolution of the protein crystals was achieved at 0.54 A resolution for a small protein, crambin. In such high resolution crystals, almost all of hydrogen atoms of proteins and some hydrogen atoms of bound water molecules are experimentally observed. In addition, outer-shell electrons of proteins can be analyzed by the multipole refinement procedure. However, the influence of X-rays should be precisely estimated in order to derive meaningful information from the crystallographic results. In this review, we summarize refinement procedures, current status and perspectives for ultra high resolution protein crystallography. (author)

Evaluation of Cancer Metabolomics Using ex vivo High Resolution Magic Angle Spinning (HRMAS Magnetic Resonance Spectroscopy (MRS

Directory of Open Access Journals (Sweden)

Taylor L. Fuss

2016-03-01

Full Text Available According to World Health Organization (WHO estimates, cancer is responsible for more deaths than all coronary heart disease or stroke worldwide, serving as a major public health threat around the world. High resolution magic angle spinning (HRMAS magnetic resonance spectroscopy (MRS has demonstrated its usefulness in the identification of cancer metabolic markers with the potential to improve diagnosis and prognosis for the oncology clinic, due partially to its ability to preserve tissue architecture for subsequent histological and molecular pathology analysis. Capable of the quantification of individual metabolites, ratios of metabolites, and entire metabolomic profiles, HRMAS MRS is one of the major techniques now used in cancer metabolomic research. This article reviews and discusses literature reports of HRMAS MRS studies of cancer metabolomics published between 2010 and 2015 according to anatomical origins, including brain, breast, prostate, lung, gastrointestinal, and neuroendocrine cancers. These studies focused on improving diagnosis and understanding patient prognostication, monitoring treatment effects, as well as correlating with the use of in vivo MRS in cancer clinics.

Method for high resolution magnetic resonance analysis using magic angle technique

Science.gov (United States)

Wind, Robert A.; Hu, Jian Zhi

2003-12-30

A method of performing a magnetic resonance analysis of a biological object that includes placing the object in a main magnetic field (that has a static field direction) and in a radio frequency field; rotating the object at a frequency of less than about 100 Hz around an axis positioned at an angle of about 54.degree.44' relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a phase-corrected magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. The object may be reoriented about the magic angle axis between three predetermined positions that are related to each other by 120.degree.. The main magnetic field may be rotated mechanically or electronically. Methods for magnetic resonance imaging of the object are also described.

High spatial resolution magnetic resonance imaging of experimental cerebral venous thrombosis with a blood pool contrast agent

International Nuclear Information System (INIS)

Spuentrup, E.; Wiethoff, A.J.; Parsons, E.C.; Spangenberg, P.; Stracke, C.P.

2010-01-01

Purpose: The purpose of this study was to investigate the feasibility of clot visualization in small sinus and cortical veins with contrast enhanced MRA in a cerebral venous thrombosis animal model using a blood pool contrast agent, Gadofosveset, and high spatial resolution imaging. Material and methods: For induction of cerebral venous thrombosis a recently developed combined interventional and microsurgical model was used. Cerebral sinus and cortical vein thrombosis was induced in six pigs. Two further pigs died during the procedure. Standard structural, time-of-flight- and phase contrast-angiograms were followed by fast time resolved high resolution 3D MRA (4D MRA) and subsequent high spatial resolution 3D MRA in the equilibrium phase with and without addition of parallel imaging. Visualization of the clots using the different sequences was subjectively compared and contrast-to-noise ratio (CNR) was assessed. Results: In the remaining six animals the procedure and MR-imaging protocol including administration of Gadofosveset was successfully completed. The 3D high resolution MRA in the equilibrium phase without the addition of parallel imaging was superior to all the other applied MR measurement techniques in terms of visualization of the clots. Only applying this sequence bridging vein thromboses were also seen as a small filling defect with a high CNR of >18. Conclusion: Only the non-accelerated high spatial resolution 3D MRA in the equilibrium in conjunction with the blood pool agent Gadofosveset allows for high-contrast visualization of very small clots in the cerebral sinus and cortical veins. Statement clinical impact: Detection of cortical vein thrombosis is of high clinical impact. Conventional MRI sequences often fail to visualize the clot. We could demonstrate that, in contrast to conventional sequences, with high spatial resolution 3D MRA in the equilibrium in conjunction with the blood pool agent Gadofosveset very small clots in the cerebral sinus and

High-resolution, in vivo magnetic resonance imaging of Drosophila at 18.8 Tesla.

Directory of Open Access Journals (Sweden)

Brian Null

Full Text Available High resolution MRI of live Drosophila was performed at 18.8 Tesla, with a field of view less than 5 mm, and administration of manganese or gadolinium-based contrast agents. This study demonstrates the feasibility of MR methods for imaging the fruit fly Drosophila with an NMR spectrometer, at a resolution relevant for undertaking future studies of the Drosophila brain and other organs. The fruit fly has long been a principal model organism for elucidating biology and disease, but without capabilities like those of MRI. This feasibility marks progress toward the development of new in vivo research approaches in Drosophila without the requirement for light transparency or destructive assays.

Atomic-resolution single-spin magnetic resonance detection concept based on tunneling force microscopy

Science.gov (United States)

Payne, A.; Ambal, K.; Boehme, C.; Williams, C. C.

2015-05-01

A study of a force detected single-spin magnetic resonance measurement concept with atomic spatial resolution is presented. The method is based upon electrostatic force detection of spin-selection rule controlled single-electron tunneling between two electrically isolated paramagnetic states. Single-spin magnetic resonance detection is possible by measuring the force detected tunneling charge noise on and off spin resonance. Simulation results of this charge noise, based upon physical models of the tunneling and spin physics, are directly compared to measured atomic force microscopy system noise. The results show that the approach could provide single-spin measurement of electrically isolated qubit states with atomic spatial resolution at room temperature.

Development of large high current density superconducting solenoid magnets for use in high energy physics experiments

International Nuclear Information System (INIS)

Green, M.A.

1977-05-01

The development of a unique type of large superconducting solenoid magnet, characterized by very high current density windings and a two-phase helium tubular cooling system is described. The development of the magnet's conceptual design and the construction of two test solenoids are described. The successful test of the superconducting coil and its tubular cooling refrigeration system is presented. The safety, environmental and economic impacts of the test program on future developments in high energy physics are shown. Large solid angle particle detectors for colliding beam physics will analyze both charged and neutral particles. In many cases, these detectors will require neutral particles, such as gamma rays, to pass through the magnet coil with minimum interaction. The magnet coils must be as thin as possible. The use of superconducting windings allows one to minimize radiation thickness, while at the same time maximizing charged particle momentum resolution and saving substantial quantities of electrical energy. The results of the experimental measurements show that large high current density solenoid magnets can be made to operate at high stored energies. The superconducting magnet development described has a positive safety and environmental impact. The use of large high current density thin superconducting solenoids has been proposed in two high energy physics experiments to be conducted at the Stanford Linear Accelerator Center and Cornell University as a result of the successful experiments described

Studies of relative gain and timing response of fine-mesh photomultiplier tubes in high magnetic fields

Energy Technology Data Exchange (ETDEWEB)

Sulkosky, V.; Allison, L.; Barber, C.; Cao, T.; Ilieva, Y.; Jin, K.; Kalicy, G.; Park, K.; Ton, N.; Zheng, X.

2016-08-01

We investigated the use of Hamamatsu fine-mesh photomultiplier tube assemblies H6152-70 and H6614-70 with regards to their gain and timing resolution in magnetic fields up to 1.9 T. Our results show that the H6614-70 assembly can operate reliably in magnetic fields exceeding 1.5 T, while preserving a reasonable timing resolution even with a gain reduction of a factor of ~100. The reduction of the relative gain of the H6152-70 is similar to the H6614-70's near 1.5 T, but its timing resolution worsens considerably at this high field.

Clinical application of bilateral high temporal and spatial resolution dynamic contrast-enhanced magnetic resonance imaging of the breast at 7 T

Energy Technology Data Exchange (ETDEWEB)

Pinker, K.; Baltzer, P.; Bernathova, M.; Weber, M.; Leithner, D.; Helbich, T.H. [Medical University Vienna, Department of Biomedical Imaging and Image-guided Therapy, Division of Molecular and Gender Imaging, Waehringer Guertel 18-20, 1090, Vienna (Austria); Bogner, W.; Trattnig, S.; Gruber, S.; Zaric, O. [Medical University Vienna, Department of Biomedical Imaging and Image-guided Therapy, MR Centre of Excellence, Vienna (Austria); Abeyakoon, O. [King' s College, Department of Radiology, London (United Kingdom); Dubsky, P. [Medical University Vienna, Department of Surgery, Vienna (Austria); Bago-Horvath, Z. [Medical University Vienna, Department of Pathology, Vienna (Austria)

2014-04-15

The objective of our study was to evaluate the clinical application of bilateral high spatial and temporal resolution dynamic contrast-enhanced magnetic resonance imaging (HR DCE-MRI) of the breast at 7 T. Following institutional review board approval 23 patients with a breast lesion (BIRADS 0, 4-5) were included in our prospective study. All patients underwent bilateral HR DCE-MRI of the breast at 7 T (spatial resolution of 0.7 mm{sup 3} voxel size, temporal resolution of 14 s). Two experienced readers (r1, r2) and one less experienced reader (r3) independently assessed lesions according to BI-RADS registered. Image quality, lesion conspicuity and artefacts were graded from 1 to 5. Sensitivity, specificity and diagnostic accuracy were assessed using histopathology as the standard of reference. HR DCE-MRI at 7 T revealed 29 lesions in 23 patients (sensitivity 100 % (19/19); specificity of 90 % (9/10)) resulting in a diagnostic accuracy of 96.6 % (28/29) with an AUC of 0.95. Overall image quality was excellent in the majority of cases (27/29) and examinations were not hampered by artefacts. There was excellent inter-reader agreement for diagnosis and image quality parameters (κ = 0.89-1). Bilateral HR DCE-MRI of the breast at 7 T is feasible with excellent image quality in clinical practice and allows accurate breast cancer diagnosis. (orig.)

In vivo high angular resolution diffusion-weighted imaging of mouse brain at 16.4 Tesla.

Directory of Open Access Journals (Sweden)

Othman I Alomair

Full Text Available Magnetic Resonance Imaging (MRI of the rodent brain at ultra-high magnetic fields (> 9.4 Tesla offers a higher signal-to-noise ratio that can be exploited to reduce image acquisition time or provide higher spatial resolution. However, significant challenges are presented due to a combination of longer T1 and shorter T2/T2* relaxation times and increased sensitivity to magnetic susceptibility resulting in severe local-field inhomogeneity artefacts from air pockets and bone/brain interfaces. The Stejskal-Tanner spin echo diffusion-weighted imaging (DWI sequence is often used in high-field rodent brain MRI due to its immunity to these artefacts. To accurately determine diffusion-tensor or fibre-orientation distribution, high angular resolution diffusion imaging (HARDI with strong diffusion weighting (b >3000 s/mm2 and at least 30 diffusion-encoding directions are required. However, this results in long image acquisition times unsuitable for live animal imaging. In this study, we describe the optimization of HARDI acquisition parameters at 16.4T using a Stejskal-Tanner sequence with echo-planar imaging (EPI readout. EPI segmentation and partial Fourier encoding acceleration were applied to reduce the echo time (TE, thereby minimizing signal decay and distortion artefacts while maintaining a reasonably short acquisition time. The final HARDI acquisition protocol was achieved with the following parameters: 4 shot EPI, b = 3000 s/mm2, 64 diffusion-encoding directions, 125×150 μm2 in-plane resolution, 0.6 mm slice thickness, and 2h acquisition time. This protocol was used to image a cohort of adult C57BL/6 male mice, whereby the quality of the acquired data was assessed and diffusion tensor imaging (DTI derived parameters were measured. High-quality images with high spatial and angular resolution, low distortion and low variability in DTI-derived parameters were obtained, indicating that EPI-DWI is feasible at 16.4T to study animal models of white

Compressed sensing cine imaging with high spatial or high temporal resolution for analysis of left ventricular function.

Science.gov (United States)

Goebel, Juliane; Nensa, Felix; Schemuth, Haemi P; Maderwald, Stefan; Gratz, Marcel; Quick, Harald H; Schlosser, Thomas; Nassenstein, Kai

2016-08-01

To assess two compressed sensing cine magnetic resonance imaging (MRI) sequences with high spatial or high temporal resolution in comparison to a reference steady-state free precession cine (SSFP) sequence for reliable quantification of left ventricular (LV) volumes. LV short axis stacks of two compressed sensing breath-hold cine sequences with high spatial resolution (SPARSE-SENSE HS: temporal resolution: 40 msec, in-plane resolution: 1.0 × 1.0 mm(2) ) and high temporal resolution (SPARSE-SENSE HT: temporal resolution: 11 msec, in-plane resolution: 1.7 × 1.7 mm(2) ) and of a reference cine SSFP sequence (standard SSFP: temporal resolution: 40 msec, in-plane resolution: 1.7 × 1.7 mm(2) ) were acquired in 16 healthy volunteers on a 1.5T MR system. LV parameters were analyzed semiautomatically twice by one reader and once by a second reader. The volumetric agreement between sequences was analyzed using paired t-test, Bland-Altman plots, and Passing-Bablock regression. Small differences were observed between standard SSFP and SPARSE-SENSE HS for stroke volume (SV; -7 ± 11 ml; P = 0.024), ejection fraction (EF; -2 ± 3%; P = 0.019), and myocardial mass (9 ± 9 g; P = 0.001), but not for end-diastolic volume (EDV; P = 0.079) and end-systolic volume (ESV; P = 0.266). No significant differences were observed between standard SSFP and SPARSE-SENSE HT regarding EDV (P = 0.956), SV (P = 0.088), and EF (P = 0.103), but for ESV (3 ± 5 ml; P = 0.039) and myocardial mass (8 ± 10 ml; P = 0.007). Bland-Altman analysis showed good agreement between the sequences (maximum bias ≤ -8%). Two compressed sensing cine sequences, one with high spatial resolution and one with high temporal resolution, showed good agreement with standard SSFP for LV volume assessment. J. Magn. Reson. Imaging 2016;44:366-374. © 2016 Wiley Periodicals, Inc.

Calibration and energy resolution study of a high dispersive power Thomson Parabola Spectrometer with monochromatic proton beams

International Nuclear Information System (INIS)

Schillaci, F.; Cirrone, G.A.P.; Cuttone, G.; Pisciotta, P.; Rifuggiato, D.; Romano, F.; Scuderi, V.; Stancampiano, C.; Tramontana, A.; Amato, A.; Caruso, G.F.; Salamone, S.; Maggiore, M.; Velyhan, A.; Margarone, D.; Palumbo, G. Parasiliti; Russo, G.

2014-01-01

A high energy resolution, high dispersive power Thomson Parabola Spectrometer has been developed at INFN-LNS in order to characterize laser-driven beams up to 30- 40 MeV for protons. This device has parallel electric and magnetic field to deflect particles of a certain charge-to-mass ratio onto parabolic traces on the detection plane. Calibration of the deflection sector is crucial for data analysis, namely energy determination of analysed beam, and to evaluate the effective energy limit and resolution. This work reports the study of monochromatic proton beams delivered by the TANDEM accelerator at LNS (Catania) in the energy range between 6 and 12.5 MeV analysed with our spectrometer which allows a precise characterization of the electric and magnetic deflections. Also the energy and the Q/A resolutions and the energy limits have been evaluated proposing a mathematical model that can be used for data analysis, for the experimental set up and for the device scalability for higher energy

High-resolution small field-of-view magnetic resonance image acquisition system using a small planar coil and a pneumatic manipulator in an open MRI scanner.

Science.gov (United States)

Miki, Kohei; Masamune, Ken

2015-10-01

Low-field open magnetic resonance imaging (MRI) is frequently used for performing image-guided neurosurgical procedures. Intraoperative magnetic resonance (MR) images are useful for tracking brain shifts and verifying residual tumors. However, it is difficult to precisely determine the boundary of the brain tumors and normal brain tissues because the MR image resolution is low, especially when using a low-field open MRI scanner. To overcome this problem, a high-resolution MR image acquisition system was developed and tested. An MR-compatible manipulator with pneumatic actuators containing an MR signal receiver with a small radiofrequency (RF) coil was developed. The manipulator had five degrees of freedom for position and orientation control of the RF coil. An 8-mm planar RF coil with resistance and inductance of 2.04 [Formula: see text] and 1.00 [Formula: see text] was attached to the MR signal receiver at the distal end of the probe. MR images of phantom test devices were acquired using the MR signal receiver and normal head coil for signal-to-noise ratio (SNR) testing. The SNR of MR images acquired using the MR signal receiver was 8.0 times greater than that of MR images acquired using the normal head coil. The RF coil was moved by the manipulator, and local MR images of a phantom with a 2-mm grid were acquired using the MR signal receiver. A wide field-of-view MR image was generated from a montage of local MR images. A small field-of-view RF system with a pneumatic manipulator was integrated in a low-field MRI scanner to allow acquisition of both wide field-of-view and high-resolution MR images. This system is promising for image-guided neurosurgery as it may allow brain tumors to be observed more clearly and removed precisely.

A compact sub-Kelvin ultrahigh vacuum scanning tunneling microscope with high energy resolution and high stability.

Science.gov (United States)

Zhang, L; Miyamachi, T; Tomanić, T; Dehm, R; Wulfhekel, W

2011-10-01

We designed a scanning tunneling microscope working at sub-Kelvin temperatures in ultrahigh vacuum (UHV) in order to study the magnetic properties on the nanoscale. An entirely homebuilt three-stage cryostat is used to cool down the microscope head. The first stage is cooled with liquid nitrogen, the second stage with liquid (4)He. The third stage uses a closed-cycle Joule-Thomson refrigerator of a cooling power of 1 mW. A base temperature of 930 mK at the microscope head was achieved using expansion of (4)He, which can be reduced to ≈400 mK when using (3)He. The cryostat has a low liquid helium consumption of only 38 ml/h and standing times of up to 280 h. The fast cooling down of the samples (3 h) guarantees high sample throughput. Test experiments with a superconducting tip show a high energy resolution of 0.3 meV when performing scanning tunneling spectroscopy. The vertical stability of the tunnel junction is well below 1 pm (peak to peak) and the electric noise floor of tunneling current is about 6fA/√Hz. Atomic resolution with a tunneling current of 1 pA and 1 mV was achieved on Au(111). The lateral drift of the microscope at stable temperature is below 20 pm/h. A superconducting spilt-coil magnet allows to apply an out-of-plane magnetic field of up to 3 T at the sample surface. The flux vortices of a Nb(110) sample were clearly resolved in a map of differential conductance at 1.1 K and a magnetic field of 0.21 T. The setup is designed for in situ preparation of tip and samples under UHV condition.

High resolution solar observations

International Nuclear Information System (INIS)

Title, A.

1985-01-01

Currently there is a world-wide effort to develop optical technology required for large diffraction limited telescopes that must operate with high optical fluxes. These developments can be used to significantly improve high resolution solar telescopes both on the ground and in space. When looking at the problem of high resolution observations it is essential to keep in mind that a diffraction limited telescope is an interferometer. Even a 30 cm aperture telescope, which is small for high resolution observations, is a big interferometer. Meter class and above diffraction limited telescopes can be expected to be very unforgiving of inattention to details. Unfortunately, even when an earth based telescope has perfect optics there are still problems with the quality of its optical path. The optical path includes not only the interior of the telescope, but also the immediate interface between the telescope and the atmosphere, and finally the atmosphere itself

High speed, High resolution terahertz spectrometers

International Nuclear Information System (INIS)

Kim, Youngchan; Yee, Dae Su; Yi, Miwoo; Ahn, Jaewook

2008-01-01

A variety of sources and methods have been developed for terahertz spectroscopy during almost two decades. Terahertz time domain spectroscopy (THz TDS)has attracted particular attention as a basic measurement method in the fields of THz science and technology. Recently, asynchronous optical sampling (AOS)THz TDS has been demonstrated, featuring rapid data acquisition and a high spectral resolution. Also, terahertz frequency comb spectroscopy (TFCS)possesses attractive features for high precision terahertz spectroscopy. In this presentation, we report on these two types of terahertz spectrometer. Our high speed, high resolution terahertz spectrometer is demonstrated using two mode locked femtosecond lasers with slightly different repetition frequencies without a mechanical delay stage. The repetition frequencies of the two femtosecond lasers are stabilized by use of two phase locked loops sharing the same reference oscillator. The time resolution of our terahertz spectrometer is measured using the cross correlation method to be 270 fs. AOS THz TDS is presented in Fig. 1, which shows a time domain waveform rapidly acquired on a 10ns time window. The inset shows a zoom into the signal with 100ps time window. The spectrum obtained by the fast Fourier Transformation (FFT)of the time domain waveform has a frequency resolution of 100MHz. The dependence of the signal to noise ratio (SNR)on the measurement time is also investigated

[Examination of upper abdominal region in high spatial resolution diffusion-weighted imaging using 3-Tesla MRI].

Science.gov (United States)

Terada, Masaki; Matsushita, Hiroki; Oosugi, Masanori; Inoue, Kazuyasu; Yaegashi, Taku; Anma, Takeshi

2009-03-20

The advantage of the higher signal-to-noise ratio (SNR) of 3-Tesla magnetic resonance imaging (3-Tesla) has the possibility of contributing to the improvement of high spatial resolution without causing image deterioration. In this study, we compared SNR and the apparent diffusion coefficient (ADC) value with 3-Tesla as the condition in the diffusion-weighted image (DWI) parameter of the 1.5-Tesla magnetic resonance imaging (1.5-Tesla) and we examined the high spatial resolution images in the imaging method [respiratory-triggering (RT) method and breath free (BF) method] and artifact (motion and zebra) in the upper abdominal region of DWI at 3-Tesla. We have optimized scan parameters based on phantom and in vivo study. As a result, 3-Tesla was able to obtain about 1.5 times SNR in comparison with the 1.5-Tesla, ADC value had few differences. Moreover, the RT method was effective in correcting the influence of respiratory movement in comparison with the BF method, and image improvement by the effective acquisition of SNR and reduction of the artifact were provided. Thus, DWI of upper abdominal region was a useful sequence for the high spatial resolution in 3-Tesla.

Low drive field amplitude for improved image resolution in magnetic particle imaging.

Science.gov (United States)

Croft, Laura R; Goodwill, Patrick W; Konkle, Justin J; Arami, Hamed; Price, Daniel A; Li, Ada X; Saritas, Emine U; Conolly, Steven M

2016-01-01

Magnetic particle imaging (MPI) is a new imaging technology that directly detects superparamagnetic iron oxide nanoparticles. The technique has potential medical applications in angiography, cell tracking, and cancer detection. In this paper, the authors explore how nanoparticle relaxation affects image resolution. Historically, researchers have analyzed nanoparticle behavior by studying the time constant of the nanoparticle physical rotation. In contrast, in this paper, the authors focus instead on how the time constant of nanoparticle rotation affects the final image resolution, and this reveals nonobvious conclusions for tailoring MPI imaging parameters for optimal spatial resolution. The authors first extend x-space systems theory to include nanoparticle relaxation. The authors then measure the spatial resolution and relative signal levels in an MPI relaxometer and a 3D MPI imager at multiple drive field amplitudes and frequencies. Finally, these image measurements are used to estimate relaxation times and nanoparticle phase lags. The authors demonstrate that spatial resolution, as measured by full-width at half-maximum, improves at lower drive field amplitudes. The authors further determine that relaxation in MPI can be approximated as a frequency-independent phase lag. These results enable the authors to accurately predict MPI resolution and sensitivity across a wide range of drive field amplitudes and frequencies. To balance resolution, signal-to-noise ratio, specific absorption rate, and magnetostimulation requirements, the drive field can be a low amplitude and high frequency. Continued research into how the MPI drive field affects relaxation and its adverse effects will be crucial for developing new nanoparticles tailored to the unique physics of MPI. Moreover, this theory informs researchers how to design scanning sequences to minimize relaxation-induced blurring for better spatial resolution or to exploit relaxation-induced blurring for MPI with

High frequency write head measurement with the phase detection magnetic force microscope

International Nuclear Information System (INIS)

Abe, M.; Tanaka, Y.

2001-01-01

We demonstrated the measurement of the high frequency (HF) magnetic field of a write head with the phase detection magnetic force microscope. An amplitude-modulated current was applied to the head coil to detect the force gradient induced by the HF magnetic field. Spatial resolution of this method was higher than that of the deflection detection method previously proposed. By the phase detection method, dynamic HF magnetic fields at the poles of the write heads were clearly imaged. HF magnetic field leakage was observed along the P2 pole shape on the air-bearing surface. The frequency dependence of the write head dynamics up to 350 MHz was also investigated. [copyright] 2001 American Institute of Physics

Angstrom-Resolution Magnetic Resonance Imaging of Single Molecules via Wave-Function Fingerprints of Nuclear Spins

Science.gov (United States)

Ma, Wen-Long; Liu, Ren-Bao

2016-08-01

Single-molecule sensitivity of nuclear magnetic resonance (NMR) and angstrom resolution of magnetic resonance imaging (MRI) are the highest challenges in magnetic microscopy. Recent development in dynamical-decoupling- (DD) enhanced diamond quantum sensing has enabled single-nucleus NMR and nanoscale NMR. Similar to conventional NMR and MRI, current DD-based quantum sensing utilizes the "frequency fingerprints" of target nuclear spins. The frequency fingerprints by their nature cannot resolve different nuclear spins that have the same noise frequency or differentiate different types of correlations in nuclear-spin clusters, which limit the resolution of single-molecule MRI. Here we show that this limitation can be overcome by using "wave-function fingerprints" of target nuclear spins, which is much more sensitive than the frequency fingerprints to the weak hyperfine interaction between the targets and a sensor under resonant DD control. We demonstrate a scheme of angstrom-resolution MRI that is capable of counting and individually localizing single nuclear spins of the same frequency and characterizing the correlations in nuclear-spin clusters. A nitrogen-vacancy-center spin sensor near a diamond surface, provided that the coherence time is improved by surface engineering in the near future, may be employed to determine with angstrom resolution the positions and conformation of single molecules that are isotope labeled. The scheme in this work offers an approach to breaking the resolution limit set by the "frequency gradients" in conventional MRI and to reaching the angstrom-scale resolution.

Synthesis of nanoparticles using high-pressure sputtering for magnetic domain imaging

International Nuclear Information System (INIS)

Shah, Prasanna; Gavrin, A.

2006-01-01

We have developed a modified sputtering gun for direct synthesis of metallic nanoparticles, and used this system to produce magnetic domain images using high-resolution Bitter microscopy (HRBM). The nanoparticles are produced at 900 mTorr inside the gun and transported to the main vacuum chamber by the pressure difference between the chamber and the gun interior. Fe particles synthesized using the particle gun have been characterized using X-ray diffraction, atomic force microscopy, and transmission electron microscopy techniques. The particles are 15-30 nm in size with a pure BCC phase. Further, we have deposited these Fe nanoparticles on magnetic recording media and observed the domain patterns using optical microscopy, scanning electron microscopy, and atomic force microscopy. We achieve a spatial resolution of at most 80 nm

Complete dipole response in 208Pb from high-resolution polarized proton scattering at 0 deg

International Nuclear Information System (INIS)

Neumann-Cosel, P. von; Kalmykov, Y.; Poltoratska, I.; Ponomarev, V. Yu.; Richter, A.; Wambach, J.; Adachi, T.; Fujita, Y.; Matsubara, H.; Sakemi, Y.; Shimizu, Y.; Tameshige, Y.; Yosoi, M.; Bertulani, C. A.; Carter, J.; Fujita, H.; Dozono, M.; Fujita, K.; Hashimoto, H.; Hatanaka, K.

2009-01-01

The structure of electric and magnetic dipole modes in 208 Pb is investigated in a high-resolution measurement of the (p-vector,p-vector') reaction under 0 deg. First results on the E1 strength in the region of the pygmy dipole resonance are reported.

Para-hydrogen raser delivers sub-millihertz resolution in nuclear magnetic resonance

Science.gov (United States)

Suefke, Martin; Lehmkuhl, Sören; Liebisch, Alexander; Blümich, Bernhard; Appelt, Stephan

2017-06-01

The precision of nuclear magnetic resonance spectroscopy (NMR) is limited by the signal-to-noise ratio, the measurement time Tm and the linewidth Δν = 1/(πT2). Overcoming the T 2 limit is possible if the nuclear spins of a molecule emit continuous radio waves. Lasers and masers are self-organized systems which emit coherent radiation in the optical and micro-wave regime. Both are based on creating a population inversion of specific energy states. Here we show continuous oscillations of proton spins of organic molecules in the radiofrequency regime (raser). We achieve this by coupling a population inversion created through signal amplification by reversible exchange (SABRE) to a high-quality-factor resonator. For the case of 15N labelled molecules, we observe multi-mode raser activity, which reports different spin quantum states. The corresponding 1H-15N J-coupled NMR spectra exhibit unprecedented sub-millihertz resolution and can be explained assuming two-spin ordered quantum states. Our findings demonstrate a substantial improvement in the frequency resolution of NMR.

Time-resolved High Spectral Resolution Observation of 2MASSW J0746425+200032AB

Energy Technology Data Exchange (ETDEWEB)

Wang, Ji; Mawet, Dimitri [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 E. California Boulevard, Pasadena, CA 91106 (United States); Prato, Lisa, E-mail: ji.wang@caltech.edu [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States)

2017-03-20

Many brown dwarfs (BDs) exhibit photometric variability at levels from tenths to tens of percents. The photometric variability is related to magnetic activity or patchy cloud coverage, characteristic of BDs near the L–T transition. Time-resolved spectral monitoring of BDs provides diagnostics of cloud distribution and condensate properties. However, current time-resolved spectral studies of BDs are limited to low spectral resolution ( R ∼ 100) with the exception of the study of Luhman 16 AB at a resolution of 100,000 using the VLT+CRIRES. This work yielded the first map of BD surface inhomogeneity, highlighting the importance and unique contribution of high spectral resolution observations. Here, we report on the time-resolved high spectral resolution observations of a nearby BD binary, 2MASSW J0746425+200032AB. We find no coherent spectral variability that is modulated with rotation. Based on simulations, we conclude that the coverage of a single spot on 2MASSW J0746425+200032AB is smaller than 1% or 6.25% if spot contrast is 50% or 80% of its surrounding flux, respectively. Future high spectral resolution observations aided by adaptive optics systems can put tighter constraints on the spectral variability of 2MASSW J0746425+200032AB and other nearby BDs.

High-Resolution Sonars: What Resolution Do We Need for Target Recognition?

Directory of Open Access Journals (Sweden)

Pailhas Yan

2010-01-01

Full Text Available Target recognition in sonar imagery has long been an active research area in the maritime domain, especially in the mine-counter measure context. Recently it has received even more attention as new sensors with increased resolution have been developed; new threats to critical maritime assets and a new paradigm for target recognition based on autonomous platforms have emerged. With the recent introduction of Synthetic Aperture Sonar systems and high-frequency sonars, sonar resolution has dramatically increased and noise levels decreased. Sonar images are distance images but at high resolution they tend to appear visually as optical images. Traditionally algorithms have been developed specifically for imaging sonars because of their limited resolution and high noise levels. With high-resolution sonars, algorithms developed in the image processing field for natural images become applicable. However, the lack of large datasets has hampered the development of such algorithms. Here we present a fast and realistic sonar simulator enabling development and evaluation of such algorithms.We develop a classifier and then analyse its performances using our simulated synthetic sonar images. Finally, we discuss sensor resolution requirements to achieve effective classification of various targets and demonstrate that with high resolution sonars target highlight analysis is the key for target recognition.

High-resolution ex vivo magnetic resonance angiography: a feasibility study on biological and medical tissues

Directory of Open Access Journals (Sweden)

Boel Lene WT

2010-03-01

Full Text Available Abstract Background In biomedical sciences, ex vivo angiography is a practical mean to elucidate vascular structures three-dimensionally with simultaneous estimation of intravascular volume. The objectives of this study were to develop a magnetic resonance (MR method for ex vivo angiography and to compare the findings with computed tomography (CT. To demonstrate the usefulness of this method, examples are provided from four different tissues and species: the human placenta, a rice field eel, a porcine heart and a turtle. Results The optimal solution for ex vivo MR angiography (MRA was a compound containing gelatine (0.05 g/mL, the CT contrast agent barium sulphate (0.43 mol/L and the MR contrast agent gadoteric acid (2.5 mmol/L. It was possible to perform angiography on all specimens. We found that ex vivo MRA could only be performed on fresh tissue because formalin fixation makes the blood vessels permeable to the MR contrast agent. Conclusions Ex vivo MRA provides high-resolution images of fresh tissue and delineates fine structures that we were unable to visualise by CT. We found that MRA provided detailed information similar to or better than conventional CTA in its ability to visualize vessel configuration while avoiding interfering signals from adjacent bones. Interestingly, we found that vascular tissue becomes leaky when formalin-fixed, leading to increased permeability and extravascular leakage of MR contrast agent.

High-resolution nuclear magnetic resonance imaging and single photon emission computerized tomography--cerebral blood flow in a case of pure sensory stroke and mild dementia owing to subcortical arteriosclerotic encephalopathy (Binswanger's disease)

DEFF Research Database (Denmark)

De Chiara, S; Lassen, N A; Andersen, A R

1987-01-01

hypertensive, 72-year-old patient with PSS, CT scanning and conventional nuclear magnetic resonance imaging (NMRI) scanning using a 7-mm-thick slice on a 1.5 Tesla instrument all failed to visualize the thalamic infarct. Using the high-resolution mode with 2-mm slice thickness it was, however, clearly seen...

High spatial and temporal resolution retrospective cine cardiovascular magnetic resonance from shortened free breathing real-time acquisitions.

Science.gov (United States)

Xue, Hui; Kellman, Peter; Larocca, Gina; Arai, Andrew E; Hansen, Michael S

2013-11-14

Cine cardiovascular magnetic resonance (CMR) is challenging in patients who cannot perform repeated breath holds. Real-time, free-breathing acquisition is an alternative, but image quality is typically inferior. There is a clinical need for techniques that achieve similar image quality to the segmented cine using a free breathing acquisition. Previously, high quality retrospectively gated cine images have been reconstructed from real-time acquisitions using parallel imaging and motion correction. These methods had limited clinical applicability due to lengthy acquisitions and volumetric measurements obtained with such methods have not previously been evaluated systematically. This study introduces a new retrospective reconstruction scheme for real-time cine imaging which aims to shorten the required acquisition. A real-time acquisition of 16-20s per acquired slice was inputted into a retrospective cine reconstruction algorithm, which employed non-rigid registration to remove respiratory motion and SPIRiT non-linear reconstruction with temporal regularization to fill in missing data. The algorithm was used to reconstruct cine loops with high spatial (1.3-1.8 × 1.8-2.1 mm²) and temporal resolution (retrospectively gated, 30 cardiac phases, temporal resolution 34.3 ± 9.1 ms). Validation was performed in 15 healthy volunteers using two different acquisition resolutions (256 × 144/192 × 128 matrix sizes). For each subject, 9 to 12 short axis and 3 long axis slices were imaged with both segmented and real-time acquisitions. The retrospectively reconstructed real-time cine images were compared to a traditional segmented breath-held acquisition in terms of image quality scores. Image quality scoring was performed by two experts using a scale between 1 and 5 (poor to good). For every subject, LAX and three SAX slices were selected and reviewed in the random order. The reviewers were blinded to the reconstruction approach and acquisition protocols and

An alternative 3D inversion method for magnetic anomalies with depth resolution

Directory of Open Access Journals (Sweden)

M. Chiappini

2006-06-01

Full Text Available This paper presents a new method to invert magnetic anomaly data in a variety of non-complex contexts when a priori information about the sources is not available. The region containing magnetic sources is discretized into a set of homogeneously magnetized rectangular prisms, polarized along a common direction. The magnetization distribution is calculated by solving an underdetermined linear system, and is accomplished through the simultaneous minimization of the norm of the solution and the misfit between the observed and the calculated field. Our algorithm makes use of a dipolar approximation to compute the magnetic field of the rectangular blocks. We show how this approximation, in conjunction with other correction factors, presents numerous advantages in terms of computing speed and depth resolution, and does not affect significantly the success of the inversion. The algorithm is tested on both synthetic and real magnetic datasets.

Principles and simulations of high-resolution STM imaging with a flexible tip apex

Czech Academy of Sciences Publication Activity Database

Krejčí, Ondřej; Hapala, Prokop; Ondráček, Martin; Jelínek, Pavel

2017-01-01

Roč. 95, č. 4 (2017), 1-9, č. článku 045407. ISSN 2469-9950 R&D Projects: GA ČR(CZ) GC14-16963J Institutional support: RVO:68378271 Keywords : STM * AFM * high-resolution Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.836, year: 2016

Motion robust high resolution 3D free-breathing pulmonary MRI using dynamic 3D image self-navigator.

Science.gov (United States)

Jiang, Wenwen; Ong, Frank; Johnson, Kevin M; Nagle, Scott K; Hope, Thomas A; Lustig, Michael; Larson, Peder E Z

2018-06-01

To achieve motion robust high resolution 3D free-breathing pulmonary MRI utilizing a novel dynamic 3D image navigator derived directly from imaging data. Five-minute free-breathing scans were acquired with a 3D ultrashort echo time (UTE) sequence with 1.25 mm isotropic resolution. From this data, dynamic 3D self-navigating images were reconstructed under locally low rank (LLR) constraints and used for motion compensation with one of two methods: a soft-gating technique to penalize the respiratory motion induced data inconsistency, and a respiratory motion-resolved technique to provide images of all respiratory motion states. Respiratory motion estimation derived from the proposed dynamic 3D self-navigator of 7.5 mm isotropic reconstruction resolution and a temporal resolution of 300 ms was successful for estimating complex respiratory motion patterns. This estimation improved image quality compared to respiratory belt and DC-based navigators. Respiratory motion compensation with soft-gating and respiratory motion-resolved techniques provided good image quality from highly undersampled data in volunteers and clinical patients. An optimized 3D UTE sequence combined with the proposed reconstruction methods can provide high-resolution motion robust pulmonary MRI. Feasibility was shown in patients who had irregular breathing patterns in which our approach could depict clinically relevant pulmonary pathologies. Magn Reson Med 79:2954-2967, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

High-resolution magnetic resonance imaging of the wrist: Normal anatomy

Energy Technology Data Exchange (ETDEWEB)

Baker, L.L.; Hajek, P.C.; Bjoerkengren, A.; Sartoris, D.J.; Resnick, D.; Galbraith, R.; Gelberman, R.H.

1987-02-01

Magnetic resonance imaging (MRI) provided adequate depiction of carpal soft tissue structures in normal volunteers, as well as accurate anatomic correlation with cadaveric specimens. Using a high field strength system and surface coil techniques, the intricate anatomy of the wrist was best defined on long TR short TE images. However, from a practical view, T1 weighted images (TR 600 ms, TE 25 ms) were most useful because of short imaging times, satisfactory image quality, and the absence of motion artifacts. The coronal plane provided the clearest definition of important structures. Potential diagnostic limitations exist due to the inability of MRI to clearly delineate articular cartilage, joint capsules, and small interosseous ligaments. The presence of intra-articular fluid in both living subjects and cadaveric specimens, however, allowed for fine depiction of these structures on T2 weighted images.

High resolution SPM imaging of organic molecules with functionalized tips

Czech Academy of Sciences Publication Activity Database

Jelínek, Pavel

2017-01-01

Roč. 29, č. 34 (2017), 1-18, č. článku 343002. ISSN 0953-8984 R&D Projects: GA MŠk LM2015087; GA MŠk 8E15B010; GA ČR(CZ) GC14-16963J Grant - others:AV ČR(CZ) Praemium Academiae Institutional support: RVO:68378271 Keywords : atomic- force microscopy * scanning tunneling microscope * on-surface synthesis * single-molecule * AFM * STM * high resolution * molecules * surfaces Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 2.649, year: 2016

Real-time magnetic resonance imaging of highly dynamic granular phenomena

Science.gov (United States)

Penn, Alexander; Pruessmann, Klaas P.; Müller, Christoph

Probing non-intrusively the interior of three-dimensional granular systems is a challenging task for which a number of imaging techniques have been applied including positron emission particle tracking, X-ray tomography and magnetic resonance imaging (MRI). A particular advantage of MRI is its versatility allowing quantitative velocimetry through phase contrast encoding and tagging, arbitrary slice orientations and the flexibility to trade spatial for temporal resolution and vice versa during image reconstruction. However, previous attempts to image granular systems using MRI were often limited to (pseudo-) steady state systems due to the poor temporal resolution of conventional imaging methodology. Here we present an experimental approach that overcomes previous limitations in temporal resolution by implementing a variety of methodological advances, viz. parallel data acquisition through tailored multiple receiver coils, fast gradient readouts for time-efficient data sampling and engineered granular materials that contain signal sources of high proton density. Achieving a spatial and temporal resolution of, respectively, 2 mm x 2 mm and 50 ms, we were able to image highly dynamic phenomena in granular media such as bubble coalescence and granular compaction waves.

Large-scale high-resolution scanning Hall probe microscope used for MgB2 filament characterization

International Nuclear Information System (INIS)

Cambel, V; Fedor, J; Gregusova, D; Kovac, P; Husek, I

2005-01-01

The scanning Hall probe microscope (SHPM) is an important imaging tool used for detailed studies of superconductors in basic science as well as in the industrial sector. It can be used for the studies of losses, current distribution, and effects at grain boundaries. However, only a few SHPMs for magnetic field imaging at temperatures below 77 K have been proposed up to now, most of them designed for small-area (∼10x10 μm 2 ) scanning. We present a large-scale low-temperature SHPM developed for imaging the entire magnetic field in close proximity to magnetic and superconducting samples at 4.2-300 K. The microscope combines a large scanned area and high spatial and magnetic field resolution. The instrument is designed as an insert of standard helium flowing cryostats. The Hall sensor scans an area up to 7 x 25 mm 2 in the whole temperature interval with a spatial resolution better than 5 μm. The presented system is used for the study of ex situ prepared MgB 2 filament. We show that external magnetic field induces local supercurrents in the MgB 2 , from which the critical current can be estimated. Moreover, it indicates the microstructure and space homogeneity of the superconductor

A scanning Hall probe microscope for high resolution magnetic imaging down to 300 mK

International Nuclear Information System (INIS)

Khotkevych, V. V.; Bending, S. J.; Milosevic, M. V.

2008-01-01

We present the design, construction, and performance of a low-temperature scanning Hall probe microscope with submicron lateral resolution and a large scanning range. The detachable microscope head is mounted on the cold flange of a commercial 3 He-refrigerator (Oxford Instruments, Heliox VT-50) and operates between room temperature and 300 mK. It is fitted with a three-axis slip-stick nanopositioner that enables precise in situ adjustment of the probe location within a 6x6x7 mm 3 space. The local magnetic induction at the sample surface is mapped with an easily changeable microfabricated Hall probe [typically GsAs/AlGaAs or AlGaAs/InGaAs/GaAs Hall sensors with integrated scanning tunnel microscopy (STM) tunneling tips] and can achieve minimum detectable fields ≥10 mG/Hz 1/2 . The Hall probe is brought into very close proximity to the sample surface by sensing and controlling tunnel currents at the integrated STM tip. The instrument is capable of simultaneous tunneling and Hall signal acquisition in surface-tracking mode. We illustrate the potential of the system with images of superconducting vortices at the surface of a Nb thin film down to 372 mK, and also of labyrinth magnetic-domain patterns of an yttrium iron garnet film captured at room temperature.

In vivo skin moisturizing measurement by high-resolution 3 Tesla magnetic resonance imaging.

Science.gov (United States)

Mesrar, J; Ognard, J; Garetier, M; Chechin, D; Misery, L; Ben Salem, D

2017-08-01

Magnetic resonance imaging (MRI) is rarely used for the exploration of skin, even if studies have validated both feasibility of skin MRI and its interest for anatomical, physiological, and biochemical study of the skin. The purpose of this study is to explore moisturizing of the different skin layers using 3-T scan. An MRI of the heel's skin was performed using a 23 mm coil diameter on a 3T scan with a FFE (Fast Field Echo) 3D T1-weighted sequence and a TSE (Turbo Spin Echo) calculation T2-weighted sequence (pixels size of respectively 60 and 70 μm). This study was conducted on 35 healthy volunteers, who were scanned before applying moisturizer topic and 1 h after applying it. Region of interest in the stratum corneum, the epidermis and the dermis were generated on the T2 mapping. The thickness of each layer was measured. The T1 sequence allowed accurate cross-examination repositioning to ensure the comparability of the measurements. Among the 35 cases, two were excluded from the analysis because of movement artifacts. Measurements before and after moisturizer topic application displayed a T2 increase of 48.94% (P < 0.0001) in the stratum corneum and of 5.45% (P < 0.0001) in the epidermis yet without significant difference in the dermis. There was no significant link between the thickness of the stratum corneum and the T2 increase. However, there was a strong correlation between the thickness of the stratum corneum and the thickness of the epidermis (P < 0.001; rhô=0.72). High-resolution MRI allows fine exploration of anatomical and physiological properties of the skin and can further be used to extend the studies of skin hydration. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Berkeley High-Resolution Ball

International Nuclear Information System (INIS)

Diamond, R.M.

1984-10-01

Criteria for a high-resolution γ-ray system are discussed. Desirable properties are high resolution, good response function, and moderate solid angle so as to achieve not only double- but triple-coincidences with good statistics. The Berkeley High-Resolution Ball involved the first use of bismuth germanate (BGO) for anti-Compton shield for Ge detectors. The resulting compact shield permitted rather close packing of 21 detectors around a target. In addition, a small central BGO ball gives the total γ-ray energy and multiplicity, as well as the angular pattern of the γ rays. The 21-detector array is nearly complete, and the central ball has been designed, but not yet constructed. First results taken with 9 detector modules are shown for the nucleus 156 Er. The complex decay scheme indicates a transition from collective rotation (prolate shape) to single- particle states (possibly oblate) near spin 30 h, and has other interesting features

Spatial and temporal resolution requirements for quench detection in (RE)Ba2Cu3Ox magnets using Rayleigh-scattering-based fiber optic distributed sensing

International Nuclear Information System (INIS)

Chan, W K; Schwartz, J; Flanagan, G

2013-01-01

One of the key remaining challenges to safe and reliable operation of large, high temperature superconductor (HTS)-based magnet systems is quench detection and protection. Due to the slow quench propagation in HTS systems, the conventional discrete voltage-tap approach developed for NbTi and Nb 3 Sn magnets may not be sufficient. In contrast, a distributed temperature profile, generated by a distributed temperature sensor and facilitating continuous monitoring of the temperature at any monitored locations within a magnet with high spatial resolution, may be required. One such distributed temperature sensing option is the use of Rayleigh-based fiber optic sensors (FOS), which are immune to electromagnetic interference. The detection of a quench via Rayleigh-based FOS relies on converting the spectral shifts in the Rayleigh scattering spectra into temperature variations. As a result, the higher the spatial sampling resolution the larger the data processing volume, and thus the lower the temporal sampling resolution. So, for effective quench detection, which requires the quick and accurate identification of a hot spot, it is important to find a balance between the spatial and temporal resolutions executable on a given data acquisition and processing (DAQ) system. This paper discusses a method for finding an appropriate DAQ technology that matches the characteristic of a superconducting coil, and determining the acceptable resolutions for efficient and safe quench detection. A quench detection algorithm based on distributed temperature sensing is proposed and its implementation challenges are discussed. (paper)

A new high-resolution electromagnetic method for subsurface imaging

Science.gov (United States)

Feng, Wanjie

For most electromagnetic (EM) geophysical systems, the contamination of primary fields on secondary fields ultimately limits the capability of the controlled-source EM methods. Null coupling techniques were proposed to solve this problem. However, the small orientation errors in the null coupling systems greatly restrict the applications of these systems. Another problem encountered by most EM systems is the surface interference and geologic noise, which sometimes make the geophysical survey impossible to carry out. In order to solve these problems, the alternating target antenna coupling (ATAC) method was introduced, which greatly removed the influence of the primary field and reduced the surface interference. But this system has limitations on the maximum transmitter moment that can be used. The differential target antenna coupling (DTAC) method was proposed to allow much larger transmitter moments and at the same time maintain the advantages of the ATAC method. In this dissertation, first, the theoretical DTAC calculations were derived mathematically using Born and Wolf's complex magnetic vector. 1D layered and 2D blocked earth models were used to demonstrate that the DTAC method has no responses for 1D and 2D structures. Analytical studies of the plate model influenced by conductive and resistive backgrounds were presented to explain the physical phenomenology behind the DTAC method, which is the magnetic fields of the subsurface targets are required to be frequency dependent. Then, the advantages of the DTAC method, e.g., high-resolution, reducing the geologic noise and insensitive to surface interference, were analyzed using surface and subsurface numerical examples in the EMGIMA software. Next, the theoretical advantages, such as high resolution and insensitive to surface interference, were verified by designing and developing a low-power (moment of 50 Am 2) vertical-array DTAC system and testing it on controlled targets and scaled target coils. At last, a

Generation of high magnetic fields using superconducting magnets

International Nuclear Information System (INIS)

Kiyoshi, T.; Otsuka, A.; Kosuge, M.; Yuyama, M.; Nagai, H.; Matsumoto, F.

2006-01-01

High-field superconducting magnets have opened new frontiers for several kinds of applications, such as fusion reactors, particle accelerators, and nuclear magnetic resonance (NMR) spectrometers. The present record for the highest field in a fully superconducting state is 23.4 T. It was achieved with a combination of NbTi, Nb 3 Sn, and Bi-2212 conductors in 1999. Since high T c (critical temperature) superconductors (HTS) have sufficiently high critical current density even in excess of 30 T, they are promising for use as high-field superconducting magnets. However, several problems still remain to be resolved for practical applications, and the use of HTS coils will be limited to the inner part of a high-field magnet system in the near future. The required technologies to develop a high-field superconducting magnet with a field of up to 28 T have already been established. Such a magnet is certain to provide information to all leading research areas

High-resolution ultrasonography in assessing temporomandibular joint disc position.

Science.gov (United States)

Talmaceanu, Daniel; Lenghel, Lavinia Manuela; Bolog, Nicolae; Popa Stanila, Roxana; Buduru, Smaranda; Leucuta, Daniel Corneliu; Rotar, Horatiu; Baciut, Mihaela; Baciut, Grigore

2018-02-04

The purpose of this study was to determine the diagnostic value of high-resolution ultrasonography (US) in temporomandibular joint (TMJ) disc displacements. A number of 74 patients (148 TMJs) with signs and symptoms of TMJ disorders, according to the Research Diagnostic Criteria for Temporomandibular Disorders, were included in this study. All patients received US and magnetic resonance imaging (MRI) of both TMJs 1 to 5 days after the clinical examination. MRI examinations were performed using 1.5 T MRI equipment (Siemens Avanto, Siemens, Erlangen). Ultrasonographic examination was performed on a Hitachi EUB 8500 (Hitachi Medical Corp., Tokyo, Japan) scanner with L 54 M6.5-13 MHz linear transducer. MRI depicted 68 (45.95%) normal joints, 47 (31.76%) with disc displacement with reduction, 33 (22.3%) with disc displacement without reduction and 34 (22.97%) with degenerative changes. US detected 78 (52.7%) normal joints, 37 (25%) with disc displacement with reduction, 33 (22.3%) with disc displacement without reduction and 21 (14.19%) with degenerative changes. Compared to MRI, US showed a sensitivity of 93.1%, specificity of 87.88%, accuracy of 90.32%, a positive predictive value of 87.1% and a negative predictive value of 93.55% for overall diagnosis of disc displacement. The Youden index was 0.81. Based on our results, high-resolution ultrasonography showed high sensitivity, specificity and accuracy in the diagnosis of TMJ disc displacement. It could be a valuable imaging technique in assessing TMJ disc position. The diagnostic value of high-resolution ultrasonography depends strictly on the examiner's skills and on the equipment used.

A high-resolution computational localization method for transcranial magnetic stimulation mapping.

Science.gov (United States)

Aonuma, Shinta; Gomez-Tames, Jose; Laakso, Ilkka; Hirata, Akimasa; Takakura, Tomokazu; Tamura, Manabu; Muragaki, Yoshihiro

2018-05-15

Transcranial magnetic stimulation (TMS) is used for the mapping of brain motor functions. The complexity of the brain deters determining the exact localization of the stimulation site using simplified methods (e.g., the region below the center of the TMS coil) or conventional computational approaches. This study aimed to present a high-precision localization method for a specific motor area by synthesizing computed non-uniform current distributions in the brain for multiple sessions of TMS. Peritumoral mapping by TMS was conducted on patients who had intra-axial brain neoplasms located within or close to the motor speech area. The electric field induced by TMS was computed using realistic head models constructed from magnetic resonance images of patients. A post-processing method was implemented to determine a TMS hotspot by combining the computed electric fields for the coil orientations and positions that delivered high motor-evoked potentials during peritumoral mapping. The method was compared to the stimulation site localized via intraoperative direct brain stimulation and navigated TMS. Four main results were obtained: 1) the dependence of the computed hotspot area on the number of peritumoral measurements was evaluated; 2) the estimated localization of the hand motor area in eight non-affected hemispheres was in good agreement with the position of a so-called "hand-knob"; 3) the estimated hotspot areas were not sensitive to variations in tissue conductivity; and 4) the hand motor areas estimated by this proposal and direct electric stimulation (DES) were in good agreement in the ipsilateral hemisphere of four glioma patients. The TMS localization method was validated by well-known positions of the "hand-knob" in brains for the non-affected hemisphere, and by a hotspot localized via DES during awake craniotomy for the tumor-containing hemisphere. Copyright © 2018 Elsevier Inc. All rights reserved.

Recent trends in high spin sensitivity magnetic resonance

Science.gov (United States)

Blank, Aharon; Twig, Ygal; Ishay, Yakir

2017-07-01

Magnetic resonance is a very powerful methodology that has been employed successfully in many applications for about 70 years now, resulting in a wealth of scientific, technological, and diagnostic data. Despite its many advantages, one major drawback of magnetic resonance is its relatively poor sensitivity and, as a consequence, its bad spatial resolution when examining heterogeneous samples. Contemporary science and technology often make use of very small amounts of material and examine heterogeneity on a very small length scale, both of which are well beyond the current capabilities of conventional magnetic resonance. It is therefore very important to significantly improve both the sensitivity and the spatial resolution of magnetic resonance techniques. The quest for higher sensitivity led in recent years to the development of many alternative detection techniques that seem to rival and challenge the conventional ;old-fashioned; induction-detection approach. The aim of this manuscript is to briefly review recent advances in the field, and to provide a quantitative as well as qualitative comparison between various detection methods with an eye to future potential advances and developments. We first offer a common definition of sensitivity in magnetic resonance to enable proper quantitative comparisons between various detection methods. Following that, up-to-date information about the sensitivity capabilities of the leading recently-developed detection approaches in magnetic resonance is provided, accompanied by a critical comparison between them and induction detection. Our conclusion from this comparison is that induction detection is still indispensable, and as such, it is very important to look for ways to significantly improve it. To do so, we provide expressions for the sensitivity of induction-detection, derived from both classical and quantum mechanics, that identify its main limiting factors. Examples from current literature, as well as a description of

HIGH-RESOLUTION OBSERVATIONS AND THE PHYSICS OF HIGH-VELOCITY CLOUD A0

International Nuclear Information System (INIS)

Verschuur, Gerrit L.

2013-01-01

The neutral hydrogen structure of high-velocity cloud A0 (at about –180 km s –1 ) has been mapped with a 9.'1 resolution. Gaussian decomposition of the profiles is used to separately map families of components defined by similarities in center velocities and line widths. About 70% of the H I gas is in the form of a narrow, twisted filament whose typical line widths are of the order of 24 km s –1 . Many bright features with narrow line widths of the order of 6 km s –1 , clouds, are located in and near the filament. A third category with properties between those of the filament and clouds appears in the data. The clouds are not always co-located with the broader line width filament emission as seen projected on the sky. Under the assumption that magnetic fields underlie the presence of the filament, a theorem is developed for its stability in terms of a toroidal magnetic field generated by the flow of gas along field lines. It is suggested that the axial magnetic field strength may be derived from the excess line width of the H I emission over and above that due to kinetic temperature by invoking the role of Alfvén waves that create what is in essence a form of magnetic turbulence. At a distance of 200 pc the axial and the derived toroidal magnetic field strengths in the filament are then about 6 μG while for the clouds they are about 4 μG. The dependence of the derived field strength on distance is discussed.

A high-resolution probabilistic in vivo atlas of human subcortical brain nuclei.

Science.gov (United States)

Pauli, Wolfgang M; Nili, Amanda N; Tyszka, J Michael

2018-04-17

Recent advances in magnetic resonance imaging methods, including data acquisition, pre-processing and analysis, have benefited research on the contributions of subcortical brain nuclei to human cognition and behavior. At the same time, these developments have led to an increasing need for a high-resolution probabilistic in vivo anatomical atlas of subcortical nuclei. In order to address this need, we constructed high spatial resolution, three-dimensional templates, using high-accuracy diffeomorphic registration of T 1 - and T 2 - weighted structural images from 168 typical adults between 22 and 35 years old. In these templates, many tissue boundaries are clearly visible, which would otherwise be impossible to delineate in data from individual studies. The resulting delineations of subcortical nuclei complement current histology-based atlases. We further created a companion library of software tools for atlas development, to offer an open and evolving resource for the creation of a crowd-sourced in vivo probabilistic anatomical atlas of the human brain.

Creation of nitrogen-vacancy centres in diamond with high resolution

Energy Technology Data Exchange (ETDEWEB)

Pezzagna, Sebastien; Meijer, Jan [Rubion, Ruhr-Universitaet Bochum (Germany); Wildanger, Dominik; Hell, Stefan W. [Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Goettingen (Germany); Mazarov, Paul; Wieck, Andreas D. [Lehrstuhl fuer Angewandte Festkoerperphysik, Ruhr-Universitaet Bochum (Germany); Naydenov, Boris; Jelezko, Fedor; Wrachtrup, Joerg [3. Institute of Physics, University of Stuttgart (Germany)

2010-07-01

Nowadays, diamond and the nitrogen-vacancy (NV) colour centres constitute the best solid-state system in view of quantum-computing applications. It has also been shown recently that single NV centres could be used as nanoscale magnetic sensors. Such applications require the creation of single NV centres with very high resolution and with a high efficiency. The nano-implanter at the university of Bochum provides low energy nitrogen ions which can be implanted through a hole pierced in the tip of an atomic force microscope. Ultrapure diamond samples have been implanted with spot sizes of 50nm and less. Stimulated Emission Depletion (STED) microscopy has been used to characterise and resolve the implanted spots.

High-Resolution PET Detector. Final report

International Nuclear Information System (INIS)

Karp, Joel

2014-01-01

The objective of this project was to develop an understanding of the limits of performance for a high resolution PET detector using an approach based on continuous scintillation crystals rather than pixelated crystals. The overall goal was to design a high-resolution detector, which requires both high spatial resolution and high sensitivity for 511 keV gammas. Continuous scintillation detectors (Anger cameras) have been used extensively for both single-photon and PET scanners, however, these instruments were based on NaI(Tl) scintillators using relatively large, individual photo-multipliers. In this project we investigated the potential of this type of detector technology to achieve higher spatial resolution through the use of improved scintillator materials and photo-sensors, and modification of the detector surface to optimize the light response function.We achieved an average spatial resolution of 3-mm for a 25-mm thick, LYSO continuous detector using a maximum likelihood position algorithm and shallow slots cut into the entrance surface

High-resolution aeromagnetic survey of the Mono Basin-Long Valley Caldera region, California

Science.gov (United States)

Ponce, D. A.; Mangan, M.; McPhee, D.

2013-12-01

A new high-resolution aeromagnetic survey of the Mono Basin-Long Valley Caldera region greatly enhances previous magnetic interpretations that were based on older, low-resolution, and regional aeromagnetic data sets and provides new insights into volcano-tectonic processes. The surveyed area covers a 8,750 km2 NNW-trending swath situated between the Sierra Nevada to the west and the Basin and Range Province to the east. The surveyed area includes the volcanic centers of Mono Lake, Mono-Inyo Craters, Mammoth Mountain, Devils Postpile, and Long Valley Caldera. The NW-trending eastern Sierra frontal fault zone crosses through the study area, including the active Mono Lake, Silver Lake, Hartley Springs, Laurel Creek, and Hilton Creek faults. Over 6,000 line-kilometers of aeromagnetic data were collected at a constant terrain clearance of 150 m, a flight-line spacing of 400 m, and a tie-line spacing of 4 km. Data were collected via helicopter with an attached stinger housing a magnetic sensor using a Scintrex CS-3 cesium magnetometer. In the northern part of the survey area, data improve the magnetic resolution of the individual domes and coulees along Mono Craters and a circular shaped magnetic anomaly that coincides with a poorly defined ring fracture mapped by Kistler (1966). Here, aeromagnetic data combined with other geophysical data suggests that Mono Craters may have preferentially followed a pre-existing plutonic basement feature that may have controlled the sickle shape of the volcanic chain. In the northeastern part of the survey, aeromagnetic data reveal a linear magnetic anomaly that correlates with and extends a mapped fault. In the southern part of the survey, in the Sierra Nevada block just south of Long Valley Caldera, aeromagnetic anomalies correlate with NNW-trending Sierran frontal faults rather than to linear NNE-trends observed in recent seismicity over the last 30 years. These data provide an important framework for the further analysis of the

Immobilization of Pseudomonas fluorescens lipase onto magnetic nanoparticles for resolution of 2-octanol.

Science.gov (United States)

Xun, Er-na; Lv, Xiao-li; Kang, Wei; Wang, Jia-xin; Zhang, Hong; Wang, Lei; Wang, Zhi

2012-10-01

The lipase from Pseudomonas fluorescens (Lipase AK, AKL) was immobilized onto the magnetic Fe(3)O(4) nanoparticles via hydrophobic interaction. Enzyme loading and immobilization yield were determined as 21.4±0.5 mg/g and 49.2±1.8 %, respectively. The immobilized AKL was successfully used for resolution of 2-octanol with vinyl acetate used as acyl donor. Effects of organic solvent, water activity, substrate ratio, and temperature were investigated. Under the optimum conditions, the preferred isomer for AKL is the (R)-2-octanol and the highest enantioselectivity (E=71.5±2.2) was obtained with a higher enzyme activity (0.197±0.01 μmol/mg/min). The results also showed that the immobilized lipase could be easily separated from reaction media by the magnetic steel and remained 89 % of its initial activity as well as the nearly unchanged enantioselectivity after five consecutive cycles, indicating a high stability in practical operation.

Differential Search Coils Based Magnetometers: Conditioning, Magnetic Sensitivity, Spatial Resolution

Directory of Open Access Journals (Sweden)

Timofeeva Maria

2012-03-01

Full Text Available A theoretical and experimental comparison of optimized search coils based magnetometers, operating either in the Flux mode or in the classical Lenz-Faraday mode, is presented. The improvements provided by the Flux mode in terms of bandwidth and measuring range of the sensor are detailed. Theory, SPICE model and measurements are in good agreement. The spatial resolution of the sensor is studied which is an important parameter for applications in non destructive evaluation. A general expression of the magnetic sensitivity of search coils sensors is derived. Solutions are proposed to design magnetometers with reduced weight and volume without degrading the magnetic sensitivity. An original differential search coil based magnetometer, made of coupled coils, operating in flux mode and connected to a differential transimpedance amplifier is proposed. It is shown that this structure is better in terms of volume occupancy than magnetometers using two separated coils without any degradation in magnetic sensitivity. Experimental results are in good agreement with calculations.

A 10,000 yr record of high-resolution Paleosecular Variation from a flowstone of Rio Martino Cave, Northwestern Alps, Italy

Science.gov (United States)

Zanella, Elena; Tema, Evdokia; Lanci, Luca; Regattieri, Eleonora; Isola, Ilaria; Hellstrom, John C.; Costa, Emanuele; Zanchetta, Giovanni; Drysdale, Russell N.; Magrì, Federico

2018-03-01

Speleothems are potentially excellent archives of the Earth's magnetic field, capable of recording its past variations. Their characteristics, such as the continuity of the record, the possibility to be easily dated, the almost instantaneous remanence acquisition and the high time-resolution make them potentially unique high-quality Paleosecular Variation (PSV) recorders. Nevertheless, speleothems are commonly characterized by low magnetic intensities, which often limits their resolution. Here we present a paleomagnetic study performed on two cores from a flowstone from the Rio Martino Cave (Western Alps, Italy). U/Th dating indicates that the flowstone's deposition covers almost the entire Holocene, spanning the period ca. 0.5-9.0 ka, while an estimation of its mean growth rate is around 1 mm per 15 years. The flowstone is composed of columnar calcite, characterized by a highly magnetic detrital content from meta-ophiolites in the cave's catchment. This favorable geological context results in an intense magnetic signal that permits the preparation and measurement of thin (∼3 mm depth equivalent) samples, each representing around 45 yr. The Characteristic Remanent Magnetization (ChRM), isolated after systematic stepwise Alternating Field demagnetization, is well defined, with Maximum Angular Deviation (MAD) generally lower than 10°. Paleomagnetic directional data allow the reconstruction of the PSV path during the Holocene for the area. Comparison of the new data with archeomagnetic data from Italian archeological and volcanic records and using the predictions of the SHA.DIF.14k and pfm9k.1a global geomagnetic field models shows that the Rio Martino flowstone represents an excellent recorder of the Earth's magnetic field during the last 9,000 years. Our high resolution paleomagnetic record, anchored by a high-quality chronology, provides promising data both for the detection of short term geomagnetic field variations and for complementing existing regional PSV

A METHOD TO CALIBRATE THE HIGH-RESOLUTION CATANIA ASTROPHYSICAL OBSERVATORY SPECTROPOLARIMETER

Energy Technology Data Exchange (ETDEWEB)

Leone, F.; Gangi, M.; Giarrusso, M.; Scalia, C. [Università di Catania, Dipartimento di Fisica e Astronomia, Sezione Astrofisica, Via S. Sofia 78, I-95123 Catania (Italy); Avila, G. [ESO, Karl-Schwarzschild-Straße 2, D-85748, Garching bei München (Germany); Bellassai, G.; Bruno, P.; Catalano, S.; Benedetto, R. Di; Stefano, A. Di; Greco, V.; Martinetti, E.; Miraglia, M.; Munari, M.; Pontoni, C.; Scuderi, S.; Spanó, P. [INAF—Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania (Italy)

2016-05-01

The Catania Astrophysical Observatory Spectropolarimeter (CAOS) is a white-pupil cross-dispersed échelle spectrograph with a spectral resolution of up to R  = 55,000 in the 375–1100 nm range in a single exposure, with complete coverage up to 856 nm. CAOS is linked to the 36-inch telescope, at Mount Etna Observatory, with a couple of 100 μ m optical fibers and it achieves a signal-to-noise ratio better than 60 for a V  = 10 mag star in one hour. CAOS is thermally stabilized in temperature within a 0.01 K rms, so that radial velocities are measured with a precision better than 100 m s{sup −1} from a single spectral line. Linear and circular spectropolarimetric observations are possible by means of a Savart plate working in series with a half-wave and a quarter-wave retarder plate in the 376–850 nm range. As is usual for high-resolution spectropolarimeters, CAOS is suitable to measure all Stokes parameters across spectral lines and it cannot measure the absolute degree of polarization. Observations of unpolarized standard stars show that instrumental polarization is generally zero at 550 nm and can increase up to 3% at the other wavelengths. Since polarized and unpolarized standard stars are useless, we suggest a method to calibrate a high-resolution spectropolarimeter on the basis of the polarimetric properties of spectral lines formed in the presence of a magnetic field. As applied to CAOS, observations of magnetic chemically peculiar stars of the main sequence show that the cross-talk from linear to circular polarization is smaller than 0.4% and that conversion from circular to linear is less than 2.7%. Strength and wavelength dependences of cross-talk can be entirely ascribed, via numerical simulations, to the incorrect retardance of achromatic wave plates.

Application of spatially resolved high resolution crystal spectrometry to inertial confinement fusion plasmas.

Science.gov (United States)

Hill, K W; Bitter, M; Delgado-Aparacio, L; Pablant, N A; Beiersdorfer, P; Schneider, M; Widmann, K; Sanchez del Rio, M; Zhang, L

2012-10-01

High resolution (λ∕Δλ ∼ 10 000) 1D imaging x-ray spectroscopy using a spherically bent crystal and a 2D hybrid pixel array detector is used world wide for Doppler measurements of ion-temperature and plasma flow-velocity profiles in magnetic confinement fusion plasmas. Meter sized plasmas are diagnosed with cm spatial resolution and 10 ms time resolution. This concept can also be used as a diagnostic of small sources, such as inertial confinement fusion plasmas and targets on x-ray light source beam lines, with spatial resolution of micrometers, as demonstrated by laboratory experiments using a 250-μm (55)Fe source, and by ray-tracing calculations. Throughput calculations agree with measurements, and predict detector counts in the range 10(-8)-10(-6) times source x-rays, depending on crystal reflectivity and spectrometer geometry. Results of the lab demonstrations, application of the technique to the National Ignition Facility (NIF), and predictions of performance on NIF will be presented.

Astronomy at high angular resolution a compendium of techniques in the visible and near-infrared

CERN Document Server

Hussain, Gaitee; Berger, Jean-Philippe; Schmidtobreick, Linda

2016-01-01

This book offers an essential compendium of astronomical high-resolution techniques. Recent years have seen considerable developments in such techniques, which are critical to advances in many areas of astronomy. As reflected in the book, these techniques can be divided into direct methods, interferometry, and reconstruction methods, and can be applied to a huge variety of astrophysical systems, ranging from planets, single stars and binaries to active galactic nuclei, providing angular resolution in the micro- to tens of milliarcsecond scales. Written by experts in their fields, the chapters cover adaptive optics, aperture masking imaging, spectra disentangling, interferometry, lucky imaging, Roche tomography, imaging with interferometry, interferometry of AGN, AGN reverberation mapping, Doppler- and magnetic imaging of stellar surfaces, Doppler tomography, eclipse mapping, Stokes imaging, and stellar tomography. This book is intended to enable a next generation of astronomers to apply high-resolution techni...

High-resolution magnetic resonance angiography of the lower extremities with a dedicated 36-element matrix coil at 3 Tesla.

Science.gov (United States)

Kramer, Harald; Michaely, Henrik J; Matschl, Volker; Schmitt, Peter; Reiser, Maximilian F; Schoenberg, Stefan O

2007-06-01

Recent developments in hard- and software help to significantly increase image quality of magnetic resonance angiography (MRA). Parallel acquisition techniques (PAT) help to increase spatial resolution and to decrease acquisition time but also suffer from a decrease in signal-to-noise ratio (SNR). The movement to higher field strength and the use of dedicated angiography coils can further increase spatial resolution while decreasing acquisition times at the same SNR as it is known from contemporary exams. The goal of our study was to compare the image quality of MRA datasets acquired with a standard matrix coil in comparison to MRA datasets acquired with a dedicated peripheral angio matrix coil and higher factors of parallel imaging. Before the first volunteer examination, unaccelerated phantom measurements were performed with the different coils. After institutional review board approval, 15 healthy volunteers underwent MRA of the lower extremity on a 32 channel 3.0 Tesla MR System. In 5 of them MRA of the calves was performed with a PAT acceleration factor of 2 and a standard body-matrix surface coil placed at the legs. Ten volunteers underwent MRA of the calves with a dedicated 36-element angiography matrix coil: 5 with a PAT acceleration of 3 and 5 with a PAT acceleration factor of 4, respectively. The acquired volume and acquisition time was approximately the same in all examinations, only the spatial resolution was increased with the acceleration factor. The acquisition time per voxel was calculated. Image quality was rated independently by 2 readers in terms of vessel conspicuity, venous overlay, and occurrence of artifacts. The inter-reader agreement was calculated by the kappa-statistics. SNR and contrast-to-noise ratios from the different examinations were evaluated. All 15 volunteers completed the examination, no adverse events occurred. None of the examinations showed venous overlay; 70% of the examinations showed an excellent vessel conspicuity

'In vivo' and high resolution spectroscopy in solids by NMR: an instrument for transgenic plants study

International Nuclear Information System (INIS)

Colnago, L.A.; Herrmann, P.S.P.; Bernardes Filho, R.

1995-01-01

This work has developed a study on transgenic plants using two different techniques of nuclear magnetic resonance, in vivo NMR and high resolution NMR. In order to understand the gene mutations and characterize the plants constituents, NMR spectral data were analysed and discussed, then the results were presented

X-ray magnetic microscopy for correlations between magnetic domains and crystal structure

International Nuclear Information System (INIS)

Denbeaux, G.; Anderson, E.; Bates, B.; Chao, W.; Liddle, J.A.; Harteneck, B.; Pearson, A.; Salmassi, F.; Schneider, G.; Fischer, P.; Eimuller, T.; Taylor, S.; Chang, H.; Kusinski, G.J.

2002-01-01

Accurately determining the resolution of x-ray microscopes has been a challenge because good test patterns for x-ray microscopy have been hard to make. We report on a sputter-deposited multilayer imaged in cross section as a test pattern with small features and high aspect ratios. One application of high-resolution imaging is magnetic materials. Off-axis bend magnet radiation is known to have a component of circular polarization which can be used for x-ray magnetic circular dichroism. We calculate the integrated circular polarization collected by the illumination optics in the XM-1 full-field x-ray microscope. (authors)

High resolution sequence stratigraphy in China

International Nuclear Information System (INIS)

Zhang Shangfeng; Zhang Changmin; Yin Yanshi; Yin Taiju

2008-01-01

Since high resolution sequence stratigraphy was introduced into China by DENG Hong-wen in 1995, it has been experienced two development stages in China which are the beginning stage of theory research and development of theory research and application, and the stage of theoretical maturity and widely application that is going into. It is proved by practices that high resolution sequence stratigraphy plays more and more important roles in the exploration and development of oil and gas in Chinese continental oil-bearing basin and the research field spreads to the exploration of coal mine, uranium mine and other strata deposits. However, the theory of high resolution sequence stratigraphy still has some shortages, it should be improved in many aspects. The authors point out that high resolution sequence stratigraphy should be characterized quantitatively and modelized by computer techniques. (authors)

Resolution enhancement of low quality videos using a high-resolution frame

NARCIS (Netherlands)

Pham, T.Q.; Van Vliet, L.J.; Schutte, K.

2006-01-01

This paper proposes an example-based Super-Resolution (SR) algorithm of compressed videos in the Discrete Cosine Transform (DCT) domain. Input to the system is a Low-Resolution (LR) compressed video together with a High-Resolution (HR) still image of similar content. Using a training set of

High resolution, high speed ultrahigh vacuum microscopy

International Nuclear Information System (INIS)

Poppa, Helmut

2004-01-01

The history and future of transmission electron microscopy (TEM) is discussed as it refers to the eventual development of instruments and techniques applicable to the real time in situ investigation of surface processes with high resolution. To reach this objective, it was necessary to transform conventional high resolution instruments so that an ultrahigh vacuum (UHV) environment at the sample site was created, that access to the sample by various in situ sample modification procedures was provided, and that in situ sample exchanges with other integrated surface analytical systems became possible. Furthermore, high resolution image acquisition systems had to be developed to take advantage of the high speed imaging capabilities of projection imaging microscopes. These changes to conventional electron microscopy and its uses were slowly realized in a few international laboratories over a period of almost 40 years by a relatively small number of researchers crucially interested in advancing the state of the art of electron microscopy and its applications to diverse areas of interest; often concentrating on the nucleation, growth, and properties of thin films on well defined material surfaces. A part of this review is dedicated to the recognition of the major contributions to surface and thin film science by these pioneers. Finally, some of the important current developments in aberration corrected electron optics and eventual adaptations to in situ UHV microscopy are discussed. As a result of all the path breaking developments that have led to today's highly sophisticated UHV-TEM systems, integrated fundamental studies are now possible that combine many traditional surface science approaches. Combined investigations to date have involved in situ and ex situ surface microscopies such as scanning tunneling microscopy/atomic force microscopy, scanning Auger microscopy, and photoemission electron microscopy, and area-integrating techniques such as x-ray photoelectron

A high resolution solar atlas for fluorescence calculations

Science.gov (United States)

Hearn, M. F.; Ohlmacher, J. T.; Schleicher, D. G.

1983-01-01

The characteristics required of a solar atlas to be used for studying the fluorescence process in comets are examined. Several sources of low resolution data were combined to provide an absolutely calibrated spectrum from 2250 A to 7000A. Three different sources of high resolution data were also used to cover this same spectral range. The low resolution data were then used to put each high resolution spectrum on an absolute scale. The three high resolution spectra were then combined in their overlap regions to produce a single, absolutely calibrated high resolution spectrum over the entire spectral range.

High and ultra-high resolution metabolite mapping of the human brain using 1H FID MRSI at 9.4T.

Science.gov (United States)

Nassirpour, Sahar; Chang, Paul; Henning, Anke

2018-03-01

Magnetic resonance spectroscopic imaging (MRSI) is a promising technique for mapping the spatial distribution of multiple metabolites in the human brain. These metabolite maps can be used as a diagnostic tool to gain insight into several biochemical processes and diseases in the brain. In comparison to lower field strengths, MRSI at ultra-high field strengths benefits from a higher signal to noise ratio (SNR) as well as higher chemical shift dispersion, and hence spectral resolution. This study combines the benefits of an ultra-high field magnet with the advantages of an ultra-short TE and TR single-slice FID-MRSI sequence (such as negligible J-evolution and loss of SNR due to T 2 relaxation effects) and presents the first metabolite maps acquired at 9.4T in the healthy human brain at both high (voxel size of 97.6µL) and ultra-high (voxel size of 24.4µL) spatial resolutions in a scan time of 11 and 46min respectively. In comparison to lower field strengths, more anatomically-detailed maps with higher SNR from a larger number of metabolites are shown. A total of 12 metabolites including glutamate (Glu), glutamine (Gln), N-acetyl-aspartyl-glutamate (NAAG), Gamma-aminobutyric acid (GABA) and glutathione (GSH) are reliably mapped. Comprehensive description of the methodology behind these maps is provided. Copyright © 2016 Elsevier Inc. All rights reserved.

High resolution polarimeter-interferometer system for fast equilibrium dynamics and MHD instability studies on Joint-TEXT tokamak (invited)

Energy Technology Data Exchange (ETDEWEB)

Chen, J.; Zhuang, G., E-mail: ge-zhuang@hust.edu.cn; Li, Q.; Liu, Y.; Gao, L.; Zhou, Y. N.; Jian, X.; Xiong, C. Y.; Wang, Z. J. [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Brower, D. L.; Ding, W. X. [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095 (United States)

2014-11-15

A high-performance Faraday-effect polarimeter-interferometer system has been developed for the J-TEXT tokamak. This system has time response up to 1 μs, phase resolution < 0.1° and minimum spatial resolution ∼15 mm. High resolution permits investigation of fast equilibrium dynamics as well as magnetic and density perturbations associated with intrinsic Magneto-Hydro-Dynamic (MHD) instabilities and external coil-induced Resonant Magnetic Perturbations (RMP). The 3-wave technique, in which the line-integrated Faraday angle and electron density are measured simultaneously by three laser beams with specific polarizations and frequency offsets, is used. In order to achieve optimum resolution, three frequency-stabilized HCOOH lasers (694 GHz, >35 mW per cavity) and sensitive Planar Schottky Diode mixers are used, providing stable intermediate-frequency signals (0.5–3 MHz) with S/N > 50. The collinear R- and L-wave probe beams, which propagate through the plasma poloidal cross section (a = 0.25–0.27 m) vertically, are expanded using parabolic mirrors to cover the entire plasma column. Sources of systematic errors, e.g., stemming from mechanical vibration, beam non-collinearity, and beam polarization distortion are individually examined and minimized to ensure measurement accuracy. Simultaneous density and Faraday measurements have been successfully achieved for 14 chords. Based on measurements, temporal evolution of safety factor profile, current density profile, and electron density profile are resolved. Core magnetic and density perturbations associated with MHD tearing instabilities are clearly detected. Effects of non-axisymmetric 3D RMP in ohmically heated plasmas are directly observed by polarimetry for the first time.

Hith resolution {beta}-spectroscopy of the isotope {sup 36}Cl using magnetic calorimeters; Entwicklung magnetischer Mikrokalorimeter fuer die hochaufloesende Spektroskopie des {beta}-Emitters {sup 36}Cl

Energy Technology Data Exchange (ETDEWEB)

Rotzinger, H.

2006-12-13

This thesis describes the development of a high resolution magnetic calorimeter for the detection of the {beta}-spectrum of the isotope {sup 36}Cl with endpoint energy of 709.6 keV. The temperature rise of a metallic paramagnetic sensor due to an energy deposition is sensed by measuring its magnetization using a sensitive DC-SQUID magnetometer. For a high detection efficiency an 4{pi} gold absorber was used. The heat capacity and the geometry of the absorber is optimally matched by a flat sensor and an optimized meander shaped readout coil. The fabrication of the superconducting structures and the detector setup are described. In addition, the relevant noise sources, the energy resolution and the quantum efficiency are discussed. A measured {sup 36}Cl-spectrum with an energy resolution of {delta}E{sub FWHM}=750 eV is presented and compared with existing experimental and theoretical data. (orig.)

Sensitivity encoded silicon photomultiplier—a new sensor for high-resolution PET-MRI

International Nuclear Information System (INIS)

Schulz, Volkmar; Berker, Yannick; Berneking, Arne; Omidvari, Negar; Kiessling, Fabian; Gola, Alberto; Piemonte, Claudio

2013-01-01

Detectors for simultaneous positron emission tomography and magnetic resonance imaging in particular with sub-mm spatial resolution are commonly composed of scintillator crystal arrays, readout via arrays of solid state sensors, such as avalanche photo diodes (APDs) or silicon photomultipliers (SiPMs). Usually a light guide between the crystals and the sensor is used to enable the identification of crystals which are smaller than the sensor elements. However, this complicates crystal identification at the gaps and edges of the sensor arrays. A solution is to use as many sensors as crystals with a direct coupling, which unfortunately increases the complexity and power consumption of the readout electronics. Since 1997, position-sensitive APDs have been successfully used to identify sub-mm crystals. Unfortunately, these devices show a limitation in their time resolution and a degradation of spatial resolution when placed in higher magnetic fields. To overcome these limitations, this paper presents a new sensor concept that extends conventional SiPMs by adding position information via the spatial encoding of the channel sensitivity. The concept allows a direct coupling of high-resolution crystal arrays to the sensor with a reduced amount of readout channels. The theory of sensitivity encoding is detailed and linked to compressed sensing to compute unique sparse solutions. Two devices have been designed using one- and two-dimensional linear sensitivity encoding with eight and four readout channels, respectively. Flood histograms of both devices show the capability to precisely identify all 4 × 4 LYSO crystals with dimensions of 0.93 × 0.93 × 10 mm 3 . For these crystals, the energy and time resolution (MV ± SD) of the devices with one (two)-dimensional encoding have been measured to be 12.3 · (1 ± 0.047)% (13.7 · (1 ± 0.047)%) around 511 keV with a paired coincidence time resolution (full width at half maximum) of 462 · (1 ± 0.054) ps (452 · (1 ± 0

Sensitivity encoded silicon photomultiplier—a new sensor for high-resolution PET-MRI

Science.gov (United States)

Schulz, Volkmar; Berker, Yannick; Berneking, Arne; Omidvari, Negar; Kiessling, Fabian; Gola, Alberto; Piemonte, Claudio

2013-07-01

Detectors for simultaneous positron emission tomography and magnetic resonance imaging in particular with sub-mm spatial resolution are commonly composed of scintillator crystal arrays, readout via arrays of solid state sensors, such as avalanche photo diodes (APDs) or silicon photomultipliers (SiPMs). Usually a light guide between the crystals and the sensor is used to enable the identification of crystals which are smaller than the sensor elements. However, this complicates crystal identification at the gaps and edges of the sensor arrays. A solution is to use as many sensors as crystals with a direct coupling, which unfortunately increases the complexity and power consumption of the readout electronics. Since 1997, position-sensitive APDs have been successfully used to identify sub-mm crystals. Unfortunately, these devices show a limitation in their time resolution and a degradation of spatial resolution when placed in higher magnetic fields. To overcome these limitations, this paper presents a new sensor concept that extends conventional SiPMs by adding position information via the spatial encoding of the channel sensitivity. The concept allows a direct coupling of high-resolution crystal arrays to the sensor with a reduced amount of readout channels. The theory of sensitivity encoding is detailed and linked to compressed sensing to compute unique sparse solutions. Two devices have been designed using one- and two-dimensional linear sensitivity encoding with eight and four readout channels, respectively. Flood histograms of both devices show the capability to precisely identify all 4 × 4 LYSO crystals with dimensions of 0.93 × 0.93 × 10 mm3. For these crystals, the energy and time resolution (MV ± SD) of the devices with one (two)-dimensional encoding have been measured to be 12.3 · (1 ± 0.047)% (13.7 · (1 ± 0.047)%) around 511 keV with a paired coincidence time resolution (full width at half maximum) of 462 · (1 ± 0.054) ps (452 · (1 ± 0

Sensitivity encoded silicon photomultiplier--a new sensor for high-resolution PET-MRI.

Science.gov (United States)

Schulz, Volkmar; Berker, Yannick; Berneking, Arne; Omidvari, Negar; Kiessling, Fabian; Gola, Alberto; Piemonte, Claudio

2013-07-21

Detectors for simultaneous positron emission tomography and magnetic resonance imaging in particular with sub-mm spatial resolution are commonly composed of scintillator crystal arrays, readout via arrays of solid state sensors, such as avalanche photo diodes (APDs) or silicon photomultipliers (SiPMs). Usually a light guide between the crystals and the sensor is used to enable the identification of crystals which are smaller than the sensor elements. However, this complicates crystal identification at the gaps and edges of the sensor arrays. A solution is to use as many sensors as crystals with a direct coupling, which unfortunately increases the complexity and power consumption of the readout electronics. Since 1997, position-sensitive APDs have been successfully used to identify sub-mm crystals. Unfortunately, these devices show a limitation in their time resolution and a degradation of spatial resolution when placed in higher magnetic fields. To overcome these limitations, this paper presents a new sensor concept that extends conventional SiPMs by adding position information via the spatial encoding of the channel sensitivity. The concept allows a direct coupling of high-resolution crystal arrays to the sensor with a reduced amount of readout channels. The theory of sensitivity encoding is detailed and linked to compressed sensing to compute unique sparse solutions. Two devices have been designed using one- and two-dimensional linear sensitivity encoding with eight and four readout channels, respectively. Flood histograms of both devices show the capability to precisely identify all 4 × 4 LYSO crystals with dimensions of 0.93 × 0.93 × 10 mm(3). For these crystals, the energy and time resolution (MV ± SD) of the devices with one (two)-dimensional encoding have been measured to be 12.3 · (1 ± 0.047)% (13.7 · (1 ± 0.047)%) around 511 keV with a paired coincidence time resolution (full width at half maximum) of 462 · (1 ± 0.054) ps (452 · (1 ± 0

High-resolution imaging of solar system objects

International Nuclear Information System (INIS)

Goldberg, B.A.

1988-01-01

The strategy of this investigation has been to develop new high-resolution imaging capabilities and to apply them to extended observing programs. These programs have included Io's neutral sodium cloud and comets. The Io observing program was carried out at Table Mountain Observatory (1976 to 1981), providing a framework interpreting Voyager measurements of the Io torus, and serving as an important reference for studying asymmetries and time variabilities in the Jovian magnetosphere. Comet observations made with the 3.6 m Canada-France-Hawaii Telescope and 1.6 m AMOS telescope (1984 to 1987) provide basis for studying early coma development in Halley, the kinematics of its nucleus, and the internal and external structure of the nucleus. Images of GZ from the ICE encounter period form the basis for unique comparisons with in situ magnetic field and dust impact measurements to determine the ion tail and dust coma structure, respectively

High-resolution SPECT for small-animal imaging

International Nuclear Information System (INIS)

Qi Yujin

2006-01-01

This article presents a brief overview of the development of high-resolution SPECT for small-animal imaging. A pinhole collimator has been used for high-resolution animal SPECT to provide better spatial resolution and detection efficiency in comparison with a parallel-hole collimator. The theory of imaging characteristics of the pinhole collimator is presented and the designs of the pinhole aperture are discussed. The detector technologies used for the development of small-animal SPECT and the recent advances are presented. The evolving trend of small-animal SPECT is toward a multi-pinhole and a multi-detector system to obtain a high resolution and also a high detection efficiency. (authors)

High resolution geomagnetic field observations at Terra Nova bay, Antarctica

Directory of Open Access Journals (Sweden)

P. Palangio

1996-06-01

Full Text Available he preliminary results obtained from the analysis in the micropulsation frequency range of high time resolution magnetic field data recorded at the Antarctic Italian geomagnetic observatory at Terra Nova Bay for 11 consecutive days in February 1994 are reported. The spectral index over the whole Pcl-Pc5 frequency range is of the order of 3.5 and its value significantly increases beyond about 50 mHz. Spectral peaks in the Pc3 frequency range are common, especially during the daytime hours, and are probably due to the direct penetration of upstream waves in the cusp region. From the local time distribution of the micro pulsation power, a signifi - cant activity enhancement around the local magnetic noon emerges, in agreement with previous observations. The analysis of the signal polarisation characteristics in the horizontal plane shows a predominant CW polarisation in the Pcl-Pc3 frequency ranges with the major axis of the polarisation ellipse in the first quadrant.

Fast iterative segmentation of high resolution medical images

International Nuclear Information System (INIS)

Hebert, T.J.

1996-01-01

Various applications in positron emission tomography (PET), single photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI) require segmentation of 20 to 60 high resolution images of size 256x256 pixels in 3-9 seconds per image. This places particular constraints on the design of image segmentation algorithms. This paper examines the trade-offs in segmenting images based on fitting a density function to the pixel intensities using curve-fitting versus the maximum likelihood method. A quantized data representation is proposed and the EM algorithm for fitting a finite mixture density function to the quantized representation for an image is derived. A Monte Carlo evaluation of mean estimation error and classification error showed that the resulting quantized EM algorithm dramatically reduces the required computation time without loss of accuracy

Strategies for dereplication of natural compounds using high-resolution tandem mass spectrometry.

Science.gov (United States)

Kind, Tobias; Fiehn, Oliver

2017-09-01

Complete structural elucidation of natural products is commonly performed by nuclear magnetic resonance spectroscopy (NMR), but annotating compounds to most likely structures using high-resolution tandem mass spectrometry is a faster and feasible first step. The CASMI contest 2016 (Critical Assessment of Small Molecule Identification) provided spectra of eighteen compounds for the best manual structure identification in the natural products category. High resolution precursor and tandem mass spectra (MS/MS) were available to characterize the compounds. We used the Seven Golden Rules, Sirius2 and MS-FINDER software for determination of molecular formulas, and then we queried the formulas in different natural product databases including DNP, UNPD, ChemSpider and REAXYS to obtain molecular structures. We used different in-silico fragmentation tools including CFM-ID, CSI:FingerID and MS-FINDER to rank these compounds. Additional neutral losses and product ion peaks were manually investigated. This manual and time consuming approach allowed for the correct dereplication of thirteen of the eighteen natural products.

High-resolution rock-magnetic variability in shallow marine sediment: a sensitive paleoclimatic metronome

Science.gov (United States)

Arai, Kohsaku; Sakai, Hideo; Konishi, Kenji

1997-05-01

An outer shelf deposit in central Japan centered on the Olduvai normal polarity event in the reversed Matuyama chron reveals a close correlation of both the magnetic susceptibility and remanent intensity with the sedimentary cyclicities apparent in lithologies and molluscan assemblages. Two sedimentary cycles are characterized by distinctly similar, but double-peaked magnetic cyclicities. The rock-magnetic variability is primarily attributed to the relative abundance of terrigenous magnetic minerals, and the double peak of the variability is characterized by the concentration of finer-grained magnetic minerals. The concentration is suspected to be controlled by both climatic change and shifting proximity of the shoreline as a function of rise and fall of the sea level due to glacio-eustasy. Rock-magnetic study reveals the record of a 21 ka period of orbital precession cycles within the sedimentary cyclicity attributable to a 41 ka period of orbital obliquity forcing.

3D high spectral and spatial resolution imaging of ex vivo mouse brain

International Nuclear Information System (INIS)

Foxley, Sean; Karczmar, Gregory S.; Domowicz, Miriam; Schwartz, Nancy

2015-01-01

Purpose: Widely used MRI methods show brain morphology both in vivo and ex vivo at very high resolution. Many of these methods (e.g., T 2 * -weighted imaging, phase-sensitive imaging, or susceptibility-weighted imaging) are sensitive to local magnetic susceptibility gradients produced by subtle variations in tissue composition. However, the spectral resolution of commonly used methods is limited to maintain reasonable run-time combined with very high spatial resolution. Here, the authors report on data acquisition at increased spectral resolution, with 3-dimensional high spectral and spatial resolution MRI, in order to analyze subtle variations in water proton resonance frequency and lineshape that reflect local anatomy. The resulting information compliments previous studies based on T 2 * and resonance frequency. Methods: The proton free induction decay was sampled at high resolution and Fourier transformed to produce a high-resolution water spectrum for each image voxel in a 3D volume. Data were acquired using a multigradient echo pulse sequence (i.e., echo-planar spectroscopic imaging) with a spatial resolution of 50 × 50 × 70 μm 3 and spectral resolution of 3.5 Hz. Data were analyzed in the spectral domain, and images were produced from the various Fourier components of the water resonance. This allowed precise measurement of local variations in water resonance frequency and lineshape, at the expense of significantly increased run time (16–24 h). Results: High contrast T 2 * -weighted images were produced from the peak of the water resonance (peak height image), revealing a high degree of anatomical detail, specifically in the hippocampus and cerebellum. In images produced from Fourier components of the water resonance at −7.0 Hz from the peak, the contrast between deep white matter tracts and the surrounding tissue is the reverse of the contrast in water peak height images. This indicates the presence of a shoulder in the water resonance that is not

STUDY OF POSTERIOR FOSSA TUMORS BY HIGH RESOLUTION MRI

Directory of Open Access Journals (Sweden)

Sree Hari

2016-01-01

Full Text Available INTRODUCTION Magnetic Resonance Imaging (MRI is the imaging modality used for the assessment of infratentorial neoplasms. Although Computed Tomography (CT provides better demonstration of small or subtle calcifications within tumors. OBJECTIVES Study is done to assess the potential of MRI in characterisation of different tumors in posterior fossa by evaluating various unenhanced and gadolinium enhanced sequences and to compare high resolution FSE MRI sequences with routine FSE MRI sequences in diagnosing posterior fossa brain tumors. Also correlate findings on Magnetic Resonance Imaging with Pathological diagnosis. MATERIALS AND METHODS A total of 52 patients were diagnosed by CT brain as having posterior fossa brain for a year of 2 years were included in the study. In all studies MR imaging was performed with a clinical 1.5 T system (General electrical medical systems. A dedicated phased-array coil was used. RESULTS The age group ranged from 1 year to 60 years, majority were between 1 to 20 years (39%. Slight male preponderance was seen (males 29, females 23. Commonest tumor encountered in our study was vestibular schwannoma. DWI alone can differentiate different pediatric posterior fossa brain tumors. One case of pilocytic astrocytoma showed solid lesion instead of typical cystic lesion with mural nodule. One case AT-RT showed 2 lesions one in cerebrum, one in CP angle. Common feature being intra-axial lesion involving cerebellum. MRI was able to predict diagnosis in 50 of the 52 tumors. CONCLUSION Magnetic Resonance Imaging was found to be a highly sensitive imaging procedure and method of choice for posterior fossa brain tumors.

High resolution ultrasonography in ankle joint pain: Where does it stand?

Directory of Open Access Journals (Sweden)

Mennatallah Hatem Shalaby

2017-09-01

Full Text Available Background: The ankle is frequently injured in trauma, overuse syndrome and inflammatory processes. Different imaging modalities assess the ankle, including plain radiography, computed tomography (CT, magnetic resonance imaging (MRI, and ultrasonography (US. Purpose: Our objective is to assess the role of high resolution US as a valuable tool in the depiction of causes of ankle joint pain. Patients and methods: The study included 28 patients presented with ankle pain ranging in age from 17 to 60 years. They were examined by US and findings were correlated with MRI. Results: US was capable to detect various lesions (synovitis, arthritis, plantar fasciitis, tendon and ligamentous lesions. It had a sensitivity of 95.4%, a specificity of 83.3% and an overall accuracy of 92.8%. US had a limited value in detection of avascular necrosis (AVN, bone marrow oedema and fractures. Conclusion: US can be used as a first step diagnostic tool in cases of ankle pain. MRI should be spared to cases with negative or equivocal US findings. Keywords: High resolution ultrasound, Ankle joint pain, Tendons, Ligaments, Synovitis, Arthritis

Geomagnetic Paleointensity Variations as a Cheap, High-Resolution Geochronometer for Recent Mid-Ocean Ridge Processes

Science.gov (United States)

DYMENT, J.; HEMOND, C.

2001-12-01

of the data confirms the quality of the oceanic crust as a recorder of the geomagnetic variations. Future work in the framework of Project GIMNAUT include 1) the processing and interpretation of the available magnetic signals to obtain a detailed sequence of the geomagnetic fluctuations for the last 800 ka; 2) the dating of collected samples with different radiochronologic methods such as K-Ar and Ar-Ar for samples older than 100-150 ka and 230Th-238U for samples aged between 300-10 ka; and 3) the calibration of the geomagnetic intensity variation sequence as a high resolution geochronometer for the last 800 ka. Such a magnetic geochronometer would present an obvious interest for mid-ocean ridge studies, because of its low cost and simplicity of operation: it would only require the addition of a deep-sea magnetometer onto existing means of investigation such as submersibles, ROVs or AUVs. Beyond this application, this magnetic geochronometer could also be used for accurate dating of pelagic sedimentary sequences, through the analysis of relative paleointensities on cores, or of continental or island volcanic flows, through the determination of absolute paleointensities by the Thellier-Thellier method. (*) N. Arnaud, C. Bassoullet, M.. Benoit, A. Briais, F. Chabaux, A.K. Chaubey, A. Chauvin, P. Gente, H. Guillou, H. Horen, M. Kitazawa, B. Le Gall, M. Maia, M. Ravilly

A large acceptance, high-resolution detector for rare K+-decay experiments

International Nuclear Information System (INIS)

Appel, R.; Atoyan, G.S.; Bassalleck, B.; Battiste, E.; Bergman, D.R.; Boesiger, K.; Brown, D.N.; Castillo, V.; Cheung, N.; Dhawan, S.; Do, H.; Egger, J.; Eilerts, S.W.; Felder, C.; Fischer, H.; Gach, H.M.; Giles, R.; Gninenko, S.N.; Herold, W.D.; Hotmer, J.E.; Issakov, V.V.; Karavichev, O.V.; Kaspar, H.; Kraus, D.E.; Lazarus, D.M.; Lebedev, V.A.; Leipuner, L.; Lichard, P.; Lowe, J.; Lozano, J.; Lu, T.; Ma, H.; Magurno, B.; Majid, W.; Menzel, W.; Miller, C.S.; Nickelson, M.; Ober, I.; Pile, P.H.; Pislak, S.; Poblaguev, A.A.; Pomianowski, P.; Postoev, V.E.; Proskurjakov, A.L.; Rehak, P.; Robmann, P.; Schmid, B.; Sher, A.; Sher, Aleksey; Shunko, E.; Steiner, S.; Stever, T.L.; Stotzer, R.W.; Suhov, V.V.; Thompson, J.A.; Truoel, P.; Valine, C.; Weyer, H.; Wolfe, D.M.; Zeller, M.E.

2002-01-01

The detector of the E865-collaboration at the Brookhaven-AGS described here combines a magnetic spectrometer for the charged decay products of 6 GeV/c K + with excellent electromagnetic calorimetry and efficient particle identification for electrons and muons. Its high-resolution, large acceptance and high rate capability made it well suited for the study of extremely rare or forbidden decays with multi-leptonic final states such as K + →π + μ + e - , K + →π + l + l - , K + →l + ν l e - e + and K + →π + π - e + ν e down to branching ratios below 10 -11 in an intense K + beam (∼10 8 per AGS spill)

High resolution time integration for SN radiation transport

International Nuclear Information System (INIS)

Thoreson, Greg; McClarren, Ryan G.; Chang, Jae H.

2009-01-01

First-order, second-order, and high resolution time discretization schemes are implemented and studied for the discrete ordinates (S N ) equations. The high resolution method employs a rate of convergence better than first-order, but also suppresses artificial oscillations introduced by second-order schemes in hyperbolic partial differential equations. The high resolution method achieves these properties by nonlinearly adapting the time stencil to use a first-order method in regions where oscillations could be created. We employ a quasi-linear solution scheme to solve the nonlinear equations that arise from the high resolution method. All three methods were compared for accuracy and convergence rates. For non-absorbing problems, both second-order and high resolution converged to the same solution as the first-order with better convergence rates. High resolution is more accurate than first-order and matches or exceeds the second-order method

High tracking resolution detectors. Final Technical Report

International Nuclear Information System (INIS)

Vasile, Stefan; Li, Zheng

2010-01-01

High-resolution tracking detectors based on Active Pixel Sensor (APS) have been valuable tools in Nuclear Physics and High-Energy Physics research, and have contributed to major discoveries. Their integration time, radiation length and readout rate is a limiting factor for the planed luminosity upgrades in nuclear and high-energy physics collider-based experiments. The goal of this program was to demonstrate and develop high-gain, high-resolution tracking detector arrays with faster readout, and shorter radiation length than APS arrays. These arrays may operate as direct charged particle detectors or as readouts of high resolution scintillating fiber arrays. During this program, we developed in CMOS large, high-resolution pixel sensor arrays with integrated readout, and reset at pixel level. Their intrinsic gain, high immunity to surface and moisture damage, will allow operating these detectors with minimal packaging/passivation requirements and will result in radiation length superior to APS. In Phase I, we designed and fabricated arrays with calorimetric output capable of sub-pixel resolution and sub-microsecond readout rate. The technical effort was dedicated to detector and readout structure development, performance verification, as well as to radiation damage and damage annealing.

Ultra high resolution tomography

Energy Technology Data Exchange (ETDEWEB)

Haddad, W.S.

1994-11-15

Recent work and results on ultra high resolution three dimensional imaging with soft x-rays will be presented. This work is aimed at determining microscopic three dimensional structure of biological and material specimens. Three dimensional reconstructed images of a microscopic test object will be presented; the reconstruction has a resolution on the order of 1000 A in all three dimensions. Preliminary work with biological samples will also be shown, and the experimental and numerical methods used will be discussed.

A portable high-field pulsed-magnet system for single-crystal x-ray scattering studies

International Nuclear Information System (INIS)

Islam, Zahirul; Lang, Jonathan C.; Ruff, Jacob P. C.; Ross, Kathryn A.; Gaulin, Bruce D.; Nojiri, Hiroyuki; Matsuda, Yasuhiro H.; Qu Zhe

2009-01-01

We present a portable pulsed-magnet system for x-ray studies of materials in high magnetic fields (up to 30 T). The apparatus consists of a split-pair of minicoils cooled on a closed-cycle cryostat, which is used for x-ray diffraction studies with applied field normal to the scattering plane. A second independent closed-cycle cryostat is used for cooling the sample to near liquid helium temperatures. Pulsed magnetic fields (∼1 ms in total duration) are generated by discharging a configurable capacitor bank into the magnet coils. Time-resolved scattering data are collected using a combination of a fast single-photon counting detector, a multichannel scaler, and a high-resolution digital storage oscilloscope. The capabilities of this instrument are used to study a geometrically frustrated system revealing strong magnetostrictive effects in the spin-liquid state.

A Bike Built for Magnetic Mapping

Science.gov (United States)

Schattner, U.; Segev, A.; Lyakhovsky, V.

2017-12-01

Understanding the magnetic signature of the subsurface geology is crucial for structural, groundwater, earthquake propagation, and mineral studies. The cheapest measuring method is by walking with sensors. This approach yields high-resolution maps, yet its coverage is limited. We invented a new design that records magnetic data while riding a bicycle. The new concept offers an efficient, low-cost method of collecting high-resolution ground magnetic field data over rough terrain where conventional vehicles dare not venture. It improves the efficiency of the traditional method by more than five times. The Bike-magnetic scales up ground magnetism from a localized site survey to regional coverage. By now we covered 3300 square KM (about the size of Rhode Island) across northern Israel, in profile spacing of 1-2 km. Initial Total Magnetic Intensity maps reveal a myriad of new features that were not detected by the low-resolution regional aeromagnetic survey that collected data from 1000 m height.

High resolution study of the inclusive production of massive muon pairs by intense pion beams

CERN Multimedia

2002-01-01

This experiment measures with high resolution and large acceptance the inclusive production of massive muon pairs with the intense pion beam (up to $10^{10} \\pi/$pulse) in the experimental hall ECN3. The experiment explores extended M$^{2}$/s, x and transverse momentum ranges. The study of the departures of the lepton-pair production cross- section from scaling constitutes a good test of QCD ideas; in the framework of the 'Drell-Yan' process, the experiment allows a detailed study of the pion parton distribution functions. The detector consists of a beam dump, a pulsed toroidal a magnet, MWPC's and scintillator hodoscopes. Its $\\sim 2$% mass resolution at 10 GeV is adequate for the substraction of resonances in the high-mass region.

Development of a superconducting bulk magnet for NMR and MRI.

Science.gov (United States)

Nakamura, Takashi; Tamada, Daiki; Yanagi, Yousuke; Itoh, Yoshitaka; Nemoto, Takahiro; Utumi, Hiroaki; Kose, Katsumi

2015-10-01

A superconducting bulk magnet composed of six vertically stacked annular single-domain c-axis-oriented Eu-Ba-Cu-O crystals was energized to 4.74 T using a conventional superconducting magnet for high-resolution NMR spectroscopy. Shim coils, gradient coils, and radio frequency coils for high resolution NMR and MRI were installed in the 23 mm-diameter room-temperature bore of the bulk magnet. A 6.9 ppm peak-to-peak homogeneous region suitable for MRI was achieved in the central cylindrical region (6.2 mm diameter, 9.1 mm length) of the bulk magnet by using a single layer shim coil. A 21 Hz spectral resolution that can be used for high resolution NMR spectroscopy was obtained in the central cylindrical region (1.3 mm diameter, 4 mm length) of the bulk magnet by using a multichannel shim coil. A clear 3D MR image dataset of a chemically fixed mouse fetus with (50 μm)(3) voxel resolution was obtained in 5.5 h. We therefore concluded that the cryogen-free superconducting bulk magnet developed in this study is useful for high-resolution desktop NMR, MRI and mobile NMR device. Copyright © 2015 Elsevier Inc. All rights reserved.

Multi-GPU Accelerated Admittance Method for High-Resolution Human Exposure Evaluation.

Science.gov (United States)

Xiong, Zubiao; Feng, Shi; Kautz, Richard; Chandra, Sandeep; Altunyurt, Nevin; Chen, Ji

2015-12-01

A multi-graphics processing unit (GPU) accelerated admittance method solver is presented for solving the induced electric field in high-resolution anatomical models of human body when exposed to external low-frequency magnetic fields. In the solver, the anatomical model is discretized as a three-dimensional network of admittances. The conjugate orthogonal conjugate gradient (COCG) iterative algorithm is employed to take advantage of the symmetric property of the complex-valued linear system of equations. Compared against the widely used biconjugate gradient stabilized method, the COCG algorithm can reduce the solving time by 3.5 times and reduce the storage requirement by about 40%. The iterative algorithm is then accelerated further by using multiple NVIDIA GPUs. The computations and data transfers between GPUs are overlapped in time by using asynchronous concurrent execution design. The communication overhead is well hidden so that the acceleration is nearly linear with the number of GPU cards. Numerical examples show that our GPU implementation running on four NVIDIA Tesla K20c cards can reach 90 times faster than the CPU implementation running on eight CPU cores (two Intel Xeon E5-2603 processors). The implemented solver is able to solve large dimensional problems efficiently. A whole adult body discretized in 1-mm resolution can be solved in just several minutes. The high efficiency achieved makes it practical to investigate human exposure involving a large number of cases with a high resolution that meets the requirements of international dosimetry guidelines.

A field-sweep/field-lock system for superconducting magnets--Application to high-field EPR.

Science.gov (United States)

Maly, Thorsten; Bryant, Jeff; Ruben, David; Griffin, Robert G

2006-12-01

We describe a field-lock/field-sweep system for the use in superconducting magnets. The system is based on a commercially available field mapping unit and a custom designed broad-band 1H NMR probe. The NMR signal of a small water sample is used in a feedback loop to set and control the magnetic field to high accuracy. The current instrumental configuration allows field sweeps of +/-0.4 T and a resolution of up to 10(-5) T (0.1 G) and the performance of the system is demonstrated in a high-field electron paramagnetic resonance (EPR) application. The system should also be of utility in other experiments requiring precise and reproducible sweeps of the magnetic field such as DNP, ENDOR or PELDOR.

A Field-Sweep/Field-Lock System for Superconducting Magnets-Application to High-Field EPR

Science.gov (United States)

Maly, Thorsten; Bryant, Jeff; Ruben, David; Griffin, Robert G.

2007-01-01

We describe a field-lock/field-sweep system for the use in superconducting magnets. The system is based on a commercially available field mapping unit and a custom designed broad-band 1H-NMR probe. The NMR signal of a small water sample is used in a feedback loop to set and control the magnetic field to high accuracy. The current instrumental configuration allows field sweeps of ± 0.4 T and a resolution of up to 10-5 T (0.1 G) and the performance of the system is demonstrated in a high-field electron paramagnetic resonance (EPR) application. The system should also be of utility in other experiments requiring precise and reproducible sweeps of the magnetic field such as DNP, ENDOR or PELDOR. PMID:17027306

A high-resolution spectropolarimetric survey of Herbig Ae/Be stars - II. Rotation

Science.gov (United States)

Alecian, E.; Wade, G. A.; Catala, C.; Grunhut, J. H.; Landstreet, J. D.; Böhm, T.; Folsom, C. P.; Marsden, S.

2013-02-01

We report the analysis of the rotational properties of our sample of Herbig Ae/Be (HAeBe) and related stars for which we have obtained high-resolution spectropolarimetric observations. Using the projected rotational velocities measured at the surface of the stars, we have calculated the angular momentum of the sample and plotted it as a function of age. We have then compared the angular momentum and the v sin i distributions of the magnetic to the non-magnetic HAeBe stars. Finally, we have predicted v sin i of the non-magnetic, non-binary (`normal') stars in our sample when they reach the zero-age main sequence (ZAMS), and compared them to various catalogues of v sin i of main-sequence stars. First, we observe that magnetic HAeBe stars are much slower rotators than normal stars, indicating that they have been more efficiently braked than the normal stars. In fact, the magnetic stars have already lost most of their angular momentum, despite their young ages (lower than 1 Myr for some of them). Secondly, our analysis suggests that the low-mass (1.5 5 M⊙) are losing angular momentum. We propose that winds, which are expected to be stronger in massive stars, are at the origin of this phenomenon.

Feasibility of high-resolution pituitary MRI at 7.0 tesla

International Nuclear Information System (INIS)

Rotte, Alexandra A.J. de; Kolk, Anja G. van der; Rutgers, Dik; Luijten, Peter R.; Hendrikse, Jeroen; Zelissen, Pierre M.J.; Visser, Fredy

2014-01-01

Since the pituitary gland measures 3-8 mm, imaging with the highest possible spatial resolution is important for the detection of even smaller lesions such as those seen in Cushing's disease. In the current feasibility study, we tested a multi-sequence MRI protocol to visualize the pituitary gland in high resolution at 7.0 Tesla (7.0 T). Ten healthy volunteers were examined with a 7.0 T pituitary gland protocol. The protocol consisted of a T1-weighted magnetization-prepared inversion recovery (MPIR) turbo spin-echo (TSE) sequence and a T2-weighted TSE sequence. Additionally, this protocol was tested in five patients with clinical and biochemical suspicion of a microadenoma. The dedicated protocol was successful in visualizing normal pituitary anatomy. At 7.0 T compared to 1.5 T, four times as many slices covered the pituitary gland in sagittal and coronal direction. In three patients, a lesion was diagnosed at 7.0 T, and was confirmed by histopathology to be a microadenoma. Head-to-head comparisons of 7.0 T with 1.5 T and 3.0 T are needed with larger samples of patients and with imaging times feasible for clinical settings. However, the current study suggests that high-resolution 7.0 T MRI of the pituitary gland may provide new perspectives when used as a second-line diagnostic examination in the specific context of Cushing's disease. (orig.)

Feasibility of high-resolution pituitary MRI at 7.0 tesla

Energy Technology Data Exchange (ETDEWEB)

Rotte, Alexandra A.J. de; Kolk, Anja G. van der; Rutgers, Dik; Luijten, Peter R.; Hendrikse, Jeroen [University Medical Center Utrecht, Department of Radiology, Heidelberglaan 100, Postbox 85500, Utrecht (Netherlands); Zelissen, Pierre M.J. [University Medical Center Utrecht, Department of Internal Medicine (Section of Endocrinology), Utrecht (Netherlands); Visser, Fredy [University Medical Center Utrecht, Department of Radiology, Heidelberglaan 100, Postbox 85500, Utrecht (Netherlands); Philips Healthcare, Best (Netherlands)

2014-08-15

Since the pituitary gland measures 3-8 mm, imaging with the highest possible spatial resolution is important for the detection of even smaller lesions such as those seen in Cushing's disease. In the current feasibility study, we tested a multi-sequence MRI protocol to visualize the pituitary gland in high resolution at 7.0 Tesla (7.0 T). Ten healthy volunteers were examined with a 7.0 T pituitary gland protocol. The protocol consisted of a T1-weighted magnetization-prepared inversion recovery (MPIR) turbo spin-echo (TSE) sequence and a T2-weighted TSE sequence. Additionally, this protocol was tested in five patients with clinical and biochemical suspicion of a microadenoma. The dedicated protocol was successful in visualizing normal pituitary anatomy. At 7.0 T compared to 1.5 T, four times as many slices covered the pituitary gland in sagittal and coronal direction. In three patients, a lesion was diagnosed at 7.0 T, and was confirmed by histopathology to be a microadenoma. Head-to-head comparisons of 7.0 T with 1.5 T and 3.0 T are needed with larger samples of patients and with imaging times feasible for clinical settings. However, the current study suggests that high-resolution 7.0 T MRI of the pituitary gland may provide new perspectives when used as a second-line diagnostic examination in the specific context of Cushing's disease. (orig.)

Development of a high-resolution electron-beam profile monitor using Fresnel zone plates

International Nuclear Information System (INIS)

Nakamura, Norio; Sakai, Hiroshi; Muto, Toshiya; Hayano, Hitoshi

2004-01-01

We present a high-resolution and real-time beam profile monitor using Fresnel zone plates (FZPs) developed in the KEK-ATF damping ring. The monitor system has an X-ray imaging optics with two FZPs. In this monitor, the synchrotron radiation from the electron beam at the bending magnet is monochromatized by a crystal monochromator and the transverse electron beam image is twenty-times magnified by the two FZPs and detected on an X-ray CCD camera. The expected spatial resolution for the selected photon energy of 3.235 keV is less than 1 μm. With the beam profile monitor, we succeeded in obtaining a clear electron-beam image and measuring the extremely small beam size less than 10 μm. It is greatly expected that the beam profile monitor will be used in high-brilliance light sources and low-emittance accelerators. (author)

Wall enhancement on high-resolution magnetic resonance imaging may predict an unsteady state of an intracranial saccular aneurysm

Energy Technology Data Exchange (ETDEWEB)

Hu, Peng; Zhang, Hong-Qi [Capital Medical University, Department of Neurosurgery, Xuanwu Hospital, Beijing (China); Yang, Qi [Capital Medical University, Department of Radiology, Xuanwu Hospital, Beijing (China); Wang, Dan-Dan [Capital Medical University, Department of Clinical Pathology, Xuanwu Hospital, Beijing (China); Guan, Shao-Chen [Capital Medical University, Department of Evidence-Based Medicine, Xuanwu Hospital, Beijing (China)

2016-10-15

The aneurysm wall has been reported to play a critical role in the formation, development, and even rupture of an aneurysm. We used high-resolution magnetic resonance imaging (HRMRI) to investigate the aneurysm wall in an effort to identify evidence of inflammation invasion and define its relationship with aneurysm behavior. Patients with intracranial aneurysms who were prospectively evaluated using HRMRI between July 2013 and June 2014 were enrolled in this study. The aneurysm's wall enhancement and evidence of inflammation invasion were determined. In addition, the relationship between aneurysm wall enhancement and aneurysm size and symptoms, including ruptured aneurysms, giant unruptured intracranial aneurysms (UIAs) presenting as mass effect, progressively growing aneurysms, and aneurysms associated with neurological symptoms, was statistically analyzed. Twenty-five patients with 30 aneurysms were available for the current study. Fourteen aneurysms showed wall enhancement, including 6 ruptured and 8 unruptured aneurysms. Evidence of inflammation was identified directly through histological studies and indirectly through intraoperative investigations and clinical courses. The statistical analysis indicated no significant correlation between aneurysm wall enhancement and aneurysm size. However, there was a strong correlation between wall enhancement and aneurysm symptoms, with a kappa value of 0.86 (95 % CI 0.68-1). Aneurysm wall enhancement on HRMRI might be a sign of inflammatory change. Symptomatic aneurysms exhibited wall enhancement on HRMRI. Wall enhancement had a high consistent correlation of symptomatic aneurysms. Therefore, wall enhancement on HRMRI might predict an unsteady state of an intracranial saccular aneurysm. (orig.)

A high resolution portable spectroscopy system

International Nuclear Information System (INIS)

Kulkarni, C.P.; Vaidya, P.P.; Paulson, M.; Bhatnagar, P.V.; Pande, S.S.; Padmini, S.

2003-01-01

Full text: This paper describes the system details of a High Resolution Portable Spectroscopy System (HRPSS) developed at Electronics Division, BARC. The system can be used for laboratory class, high-resolution nuclear spectroscopy applications. The HRPSS consists of a specially designed compact NIM bin, with built-in power supplies, accommodating a low power, high resolution MCA, and on-board embedded computer for spectrum building and communication. A NIM based spectroscopy amplifier and a HV module for detector bias are integrated (plug-in) in the bin. The system communicates with a host PC via a serial link. Along-with a laptop PC, and a portable HP-Ge detector, the HRPSS offers a laboratory class performance for portable applications

A High-Resolution In Vivo Atlas of the Human Brain's Serotonin System.

Science.gov (United States)

Beliveau, Vincent; Ganz, Melanie; Feng, Ling; Ozenne, Brice; Højgaard, Liselotte; Fisher, Patrick M; Svarer, Claus; Greve, Douglas N; Knudsen, Gitte M

2017-01-04

The serotonin (5-hydroxytryptamine, 5-HT) system modulates many important brain functions and is critically involved in many neuropsychiatric disorders. Here, we present a high-resolution, multidimensional, in vivo atlas of four of the human brain's 5-HT receptors (5-HT 1A , 5-HT 1B , 5-HT 2A , and 5-HT 4 ) and the 5-HT transporter (5-HTT). The atlas is created from molecular and structural high-resolution neuroimaging data consisting of positron emission tomography (PET) and magnetic resonance imaging (MRI) scans acquired in a total of 210 healthy individuals. Comparison of the regional PET binding measures with postmortem human brain autoradiography outcomes showed a high correlation for the five 5-HT targets and this enabled us to transform the atlas to represent protein densities (in picomoles per milliliter). We also assessed the regional association between protein concentration and mRNA expression in the human brain by comparing the 5-HT density across the atlas with data from the Allen Human Brain atlas and identified receptor- and transporter-specific associations that show the regional relation between the two measures. Together, these data provide unparalleled insight into the serotonin system of the human brain. We present a high-resolution positron emission tomography (PET)- and magnetic resonance imaging-based human brain atlas of important serotonin receptors and the transporter. The regional PET-derived binding measures correlate strongly with the corresponding autoradiography protein levels. The strong correlation enables the transformation of the PET-derived human brain atlas into a protein density map of the serotonin (5-hydroxytryptamine, 5-HT) system. Next, we compared the regional receptor/transporter protein densities with mRNA levels and uncovered unique associations between protein expression and density at high detail. This new in vivo neuroimaging atlas of the 5-HT system not only provides insight in the human brain's regional protein

Mechanical design of a high-resolution x-ray powder diffractometer at the Advanced Photon Source.

Energy Technology Data Exchange (ETDEWEB)

Shu, D.; Lee, P.; Preissner, C.; Ramanathan, M.; Beno, M.; VonDreele, R.; Ranay, R.; Ribaud, L.; Kurtz, C.; Jiao, X.; Kline, D.; Jemian, P.; Toby, B.

2007-01-01

A novel high-resolution x-ray powder diffractometer has been designed and commissioned at the bending magnet beamline 11-BM at the Advanced Photon Source (APS), Argonne National Laboratory (ANL). This state-of-the-art instrument is designed to meet challenging mechanical and optical specifications for producing high-quality powder diffraction data with high throughput. The 2600 mm (H) X 2100 mm (L) X 1700 mm (W) diffractometer consists of five subassemblies: a customized two-circle goniometer with a 3-D adjustable supporting base; a twelve-channel high-resolution crystal analyzer system with an array of precision x-ray slits; a manipulator system for a twelve scintillator x-ray detectors; a 4-D sample manipulator with cryo-cooling capability; and a robot-based sample exchange automation system. The mechanical design of the diffractometer as well as the test results of its positioning performance are presented in this paper.

Mechanical design of a high-resolution x-ray powder diffractometer at the Advanced Photon Source

International Nuclear Information System (INIS)

Shu, D.; Lee, P.; Preissner, C.; Ramanathan, M.; Beno, M.; VonDreele, R.; Ranay, R.; Ribaud, L.; Kurtz, C.; Jiao, X.; Kline, D.; Jemian, P.; Toby, B.

2007-01-01

A novel high-resolution x-ray powder diffractometer has been designed and commissioned at the bending magnet beamline 11-BM at the Advanced Photon Source (APS), Argonne National Laboratory (ANL). This state-of-the-art instrument is designed to meet challenging mechanical and optical specifications for producing high-quality powder diffraction data with high throughput. The 2600 mm (H) X 2100 mm (L) X 1700 mm (W) diffractometer consists of five subassemblies: a customized two-circle goniometer with a 3-D adjustable supporting base; a twelve-channel high-resolution crystal analyzer system with an array of precision x-ray slits; a manipulator system for a twelve scintillator x-ray detectors; a 4-D sample manipulator with cryo-cooling capability; and a robot-based sample exchange automation system. The mechanical design of the diffractometer as well as the test results of its positioning performance are presented in this paper.

Development of a Si-PM-based high-resolution PET system for small animals

International Nuclear Information System (INIS)

Yamamoto, Seiichi; Imaizumi, Masao; Watabe, Tadashi; Shimosegawa, Eku; Hatazawa, Jun; Watabe, Hiroshi; Kanai, Yasukazu

2010-01-01

A Geiger-mode avalanche photodiode (Si-PM) is a promising photodetector for PET, especially for use in a magnetic resonance imaging (MRI) system, because it has high gain and is less sensitive to a static magnetic field. We developed a Si-PM-based depth-of-interaction (DOI) PET system for small animals. Hamamatsu 4 x 4 Si-PM arrays (S11065-025P) were used for its detector blocks. Two types of LGSO scintillator of 0.75 mol% Ce (decay time: ∼45 ns; 1.1 mm x 1.2 mm x 5 mm) and 0.025 mol% Ce (decay time: ∼31 ns; 1.1 mm x 1.2 mm x 6 mm) were optically coupled in the DOI direction to form a DOI detector, arranged in a 11 x 9 matrix, and optically coupled to the Si-PM array. Pulse shape analysis was used for the DOI detection of these two types of LGSOs. Sixteen detector blocks were arranged in a 68 mm diameter ring to form the PET system. Spatial resolution was 1.6 mm FWHM and sensitivity was 0.6% at the center of the field of view. High-resolution mouse and rat images were successfully obtained using the PET system. We confirmed that the developed Si-PM-based PET system is promising for molecular imaging research.

High magnetic field MRI system

International Nuclear Information System (INIS)

Maeda, Hideaki; Urata, Masami; Satoh, Kozo

1990-01-01

A high field superconducting magnet, 4-5 T in central magnetic field, is required for magnetic resonance spectroscopic imaging (MRSI) on 31 P, essential nuclei for energy metabolism of human body. This paper reviews superconducting magnets for high field MRSI systems. Examples of the cross-sectional image and the spectrum of living animals are shown in the paper. (author)

High Resolution Elevation Contours

Data.gov (United States)

Minnesota Department of Natural Resources — This dataset contains contours generated from high resolution data sources such as LiDAR. Generally speaking this data is 2 foot or less contour interval.

Magnetic resonance imaging and spectroscopy at ultra high fields

International Nuclear Information System (INIS)

Neuberger, Thomas

2009-01-01

The goal of the work presented in this thesis was to explore the possibilities and limitations of MRI / MRS using an ultra high field of 17.6 tesla. A broad range of specific applications and MR methods, from MRI to MRSI and MRS were investigated. The main foci were on sodium magnetic resonance spectroscopic imaging of rodents, magnetic resonance spectroscopy of the mouse brain, and the detection of small amounts of iron labeled stem cells in the rat brain using MRI Sodium spectroscopic imaging was explored since it benefits tremendously from the high magnetic field. Due to the intrinsically low signal in vivo, originating from the low concentrations and short transverse relaxation times, only limited results have been achieved by other researchers until now. Results in the literature include studies conducted on large animals such as dogs to animals as small as rats. No studies performed on mice have been reported, despite the fact that the mouse is the most important laboratory animal due to the ready availability of transgenic strains. Hence, this study concentrated on sodium MRSI of small rodents, mostly mice (brain, heart, and kidney), and in the case of the brain on young rats. The second part of this work concentrated on proton magnetic resonance spectroscopy of the rodent brain. Due to the high magnetic field strength not only the increasing signal but also the extended spectral resolution was advantageous for such kind of studies. The difficulties/limitations of ultra high field MRS were also investigated. In the last part of the presented work detection limits of iron labeled stem cells in vivo using magnetic resonance imaging were explored. The studies provided very useful benchmarks for future researchers in terms of the number of labeled stem cells that are required for high-field MRI studies. Overall this work has shown many of the benefits and the areas that need special attention of ultra high fields in MR. Three topics in MRI, MRS and MRSI were

Magnetic resonance imaging and spectroscopy at ultra high fields

Energy Technology Data Exchange (ETDEWEB)

Neuberger, Thomas

2009-06-23

The goal of the work presented in this thesis was to explore the possibilities and limitations of MRI / MRS using an ultra high field of 17.6 tesla. A broad range of specific applications and MR methods, from MRI to MRSI and MRS were investigated. The main foci were on sodium magnetic resonance spectroscopic imaging of rodents, magnetic resonance spectroscopy of the mouse brain, and the detection of small amounts of iron labeled stem cells in the rat brain using MRI Sodium spectroscopic imaging was explored since it benefits tremendously from the high magnetic field. Due to the intrinsically low signal in vivo, originating from the low concentrations and short transverse relaxation times, only limited results have been achieved by other researchers until now. Results in the literature include studies conducted on large animals such as dogs to animals as small as rats. No studies performed on mice have been reported, despite the fact that the mouse is the most important laboratory animal due to the ready availability of transgenic strains. Hence, this study concentrated on sodium MRSI of small rodents, mostly mice (brain, heart, and kidney), and in the case of the brain on young rats. The second part of this work concentrated on proton magnetic resonance spectroscopy of the rodent brain. Due to the high magnetic field strength not only the increasing signal but also the extended spectral resolution was advantageous for such kind of studies. The difficulties/limitations of ultra high field MRS were also investigated. In the last part of the presented work detection limits of iron labeled stem cells in vivo using magnetic resonance imaging were explored. The studies provided very useful benchmarks for future researchers in terms of the number of labeled stem cells that are required for high-field MRI studies. Overall this work has shown many of the benefits and the areas that need special attention of ultra high fields in MR. Three topics in MRI, MRS and MRSI were

Study of a new magnetic dipole mode in the heavy deformed nuclei 154Sm, 156Gd, 158Gd, 164Dy, 168Er, and 174Yb by high-resolution electron spectroscopy

International Nuclear Information System (INIS)

Bohle, D.

1985-01-01

By inelastic electron scattering with high energy resolution a new magnetic dipole mode in heavy, deformed nuclei could be detected. For this the nuclei 154 Sm, 156 Gd, 158 Gd, 164 Dy, 168 Er, and 174 Yb were studied at the Darmstadt electron linear accelerator (DALINAC) at small momentum transfer q ≤ 0.6 fm -1 and low excitation energies. A collective magnetic dipole excitation could be discovered in all nuclei at an excitation energy of E x ≅ 66 δA -1/3 MeV whereby δ means the mass deformation. The transition strength extends in the mean to B(M1)↑ ≅ 1.3 μ N 2 . A systematic study of the nucleus 156 Gd yielded hints to a strong fragmentation of the magnetic dipole strength. A comparison of electron scattering, proton scattering, and nuclear resonance fluorescence experiments shows that the new mode is a pure orbital mode. (orig./HSI) [de

Extension of least squares spectral resolution algorithm to high-resolution lipidomics data

Energy Technology Data Exchange (ETDEWEB)

Zeng, Ying-Xu [Department of Chemistry, University of Bergen, PO Box 7803, N-5020 Bergen (Norway); Mjøs, Svein Are, E-mail: svein.mjos@kj.uib.no [Department of Chemistry, University of Bergen, PO Box 7803, N-5020 Bergen (Norway); David, Fabrice P.A. [Bioinformatics and Biostatistics Core Facility, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL) and Swiss Institute of Bioinformatics (SIB), Lausanne (Switzerland); Schmid, Adrien W. [Proteomics Core Facility, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne (Switzerland)

2016-03-31

Lipidomics, which focuses on the global study of molecular lipids in biological systems, has been driven tremendously by technical advances in mass spectrometry (MS) instrumentation, particularly high-resolution MS. This requires powerful computational tools that handle the high-throughput lipidomics data analysis. To address this issue, a novel computational tool has been developed for the analysis of high-resolution MS data, including the data pretreatment, visualization, automated identification, deconvolution and quantification of lipid species. The algorithm features the customized generation of a lipid compound library and mass spectral library, which covers the major lipid classes such as glycerolipids, glycerophospholipids and sphingolipids. Next, the algorithm performs least squares resolution of spectra and chromatograms based on the theoretical isotope distribution of molecular ions, which enables automated identification and quantification of molecular lipid species. Currently, this methodology supports analysis of both high and low resolution MS as well as liquid chromatography-MS (LC-MS) lipidomics data. The flexibility of the methodology allows it to be expanded to support more lipid classes and more data interpretation functions, making it a promising tool in lipidomic data analysis. - Highlights: • A flexible strategy for analyzing MS and LC-MS data of lipid molecules is proposed. • Isotope distribution spectra of theoretically possible compounds were generated. • High resolution MS and LC-MS data were resolved by least squares spectral resolution. • The method proposed compounds that are likely to occur in the analyzed samples. • The proposed compounds matched results from manual interpretation of fragment spectra.

Extension of least squares spectral resolution algorithm to high-resolution lipidomics data

International Nuclear Information System (INIS)

Zeng, Ying-Xu; Mjøs, Svein Are; David, Fabrice P.A.; Schmid, Adrien W.

2016-01-01

Lipidomics, which focuses on the global study of molecular lipids in biological systems, has been driven tremendously by technical advances in mass spectrometry (MS) instrumentation, particularly high-resolution MS. This requires powerful computational tools that handle the high-throughput lipidomics data analysis. To address this issue, a novel computational tool has been developed for the analysis of high-resolution MS data, including the data pretreatment, visualization, automated identification, deconvolution and quantification of lipid species. The algorithm features the customized generation of a lipid compound library and mass spectral library, which covers the major lipid classes such as glycerolipids, glycerophospholipids and sphingolipids. Next, the algorithm performs least squares resolution of spectra and chromatograms based on the theoretical isotope distribution of molecular ions, which enables automated identification and quantification of molecular lipid species. Currently, this methodology supports analysis of both high and low resolution MS as well as liquid chromatography-MS (LC-MS) lipidomics data. The flexibility of the methodology allows it to be expanded to support more lipid classes and more data interpretation functions, making it a promising tool in lipidomic data analysis. - Highlights: • A flexible strategy for analyzing MS and LC-MS data of lipid molecules is proposed. • Isotope distribution spectra of theoretically possible compounds were generated. • High resolution MS and LC-MS data were resolved by least squares spectral resolution. • The method proposed compounds that are likely to occur in the analyzed samples. • The proposed compounds matched results from manual interpretation of fragment spectra.

Data acquisition system for high resolution chopper spectrometer (HRC) at J-PARC

International Nuclear Information System (INIS)

Yano, Shin-ichiro; Itoh, Shinichi; Satoh, Setsuo; Yokoo, Tetsuya; Kawana, Daichi; Sato, Taku J.

2011-01-01

We installed the data acquisition (DAQ) system on the High Resolution Chopper Spectrometer (HRC) at beamline BL12 at the Materials and Life Science Experimental Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC). In inelastic neutron scattering experiments with the HRC, the event data of the detected neutrons are processed in the DAQ system and visualized in the form of the dynamic structure factor. We confirmed that the data analysis process works well by visualizing excitations in single-crystal magnetic systems probed by inelastic neutron scattering.

High resolution functional photoacoustic tomography of breast cancer

Energy Technology Data Exchange (ETDEWEB)

Li, Xiaoqi; Yao, Lei; Xi, Lei; Jiang, Huabei, E-mail: hjiang@bme.ufl.edu [Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611 (United States); Heldermon, Coy D. [Department of Medicine, University of Florida, Gainesville, Florida 32611 (United States)

2015-09-15

Purpose: To evaluate the feasibility of functional photoacoustic tomography (fPAT) for high resolution detection and characterization of breast cancer and to demonstrate for the first time quantitative hemoglobin concentration and oxygen saturation images of breasts that were formed with model-based reconstruction of tomographic photoacoustic data. Methods: The study was HIPAA compliant and was approved by the university institutional review board. Written informed consents were obtained from all the participants. Ten cases, including six cancer and four healthy (mean age = 50 yr; age range = 41–66 yr), were examined. Functional images of breast tissue including absolute total hemoglobin concentration (Hb{sub T}) and oxygen saturation (StO{sub 2}%) were obtained by fPAT and cross validated with magnetic resonance imaging (MRI) readings and/or histopathology. Results: Hb{sub T} and StO{sub 2}% maps from all six pathology-confirmed cancer cases (60%) show clear detection of tumor, while MR images indicate clear detection of tumor for five of six cancer cases; one small tumor was read as near-complete-resolution by MRI. The average Hb{sub T} and StO{sub 2}% value of suspicious lesion area for the cancer cases was 61.6 ± 18.9 μM/l and 67.5% ± 5.2% compared to 25.6 ± 7.4 μM/l and 65.2% ± 3.8% for background normal tissue. Conclusions: fPAT has the potential to be a significant add-on in breast cancer detection and characterization as it provides submillimeter resolution functional images of breast lesions.

Ultra-high resolution coded wavefront sensor

KAUST Repository

Wang, Congli

2017-06-08

Wavefront sensors and more general phase retrieval methods have recently attracted a lot of attention in a host of application domains, ranging from astronomy to scientific imaging and microscopy. In this paper, we introduce a new class of sensor, the Coded Wavefront Sensor, which provides high spatio-temporal resolution using a simple masked sensor under white light illumination. Specifically, we demonstrate megapixel spatial resolution and phase accuracy better than 0.1 wavelengths at reconstruction rates of 50 Hz or more, thus opening up many new applications from high-resolution adaptive optics to real-time phase retrieval in microscopy.

3D high spectral and spatial resolution imaging of ex vivo mouse brain

Energy Technology Data Exchange (ETDEWEB)

Foxley, Sean, E-mail: sean.foxley@ndcn.ox.ac.uk; Karczmar, Gregory S. [Department of Radiology, University of Chicago, Chicago, Illinois 60637 (United States); Domowicz, Miriam [Department of Pediatrics, University of Chicago, Chicago, Illinois 60637 (United States); Schwartz, Nancy [Department of Pediatrics, Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637 (United States)

2015-03-15

Purpose: Widely used MRI methods show brain morphology both in vivo and ex vivo at very high resolution. Many of these methods (e.g., T{sub 2}{sup *}-weighted imaging, phase-sensitive imaging, or susceptibility-weighted imaging) are sensitive to local magnetic susceptibility gradients produced by subtle variations in tissue composition. However, the spectral resolution of commonly used methods is limited to maintain reasonable run-time combined with very high spatial resolution. Here, the authors report on data acquisition at increased spectral resolution, with 3-dimensional high spectral and spatial resolution MRI, in order to analyze subtle variations in water proton resonance frequency and lineshape that reflect local anatomy. The resulting information compliments previous studies based on T{sub 2}{sup *} and resonance frequency. Methods: The proton free induction decay was sampled at high resolution and Fourier transformed to produce a high-resolution water spectrum for each image voxel in a 3D volume. Data were acquired using a multigradient echo pulse sequence (i.e., echo-planar spectroscopic imaging) with a spatial resolution of 50 × 50 × 70 μm{sup 3} and spectral resolution of 3.5 Hz. Data were analyzed in the spectral domain, and images were produced from the various Fourier components of the water resonance. This allowed precise measurement of local variations in water resonance frequency and lineshape, at the expense of significantly increased run time (16–24 h). Results: High contrast T{sub 2}{sup *}-weighted images were produced from the peak of the water resonance (peak height image), revealing a high degree of anatomical detail, specifically in the hippocampus and cerebellum. In images produced from Fourier components of the water resonance at −7.0 Hz from the peak, the contrast between deep white matter tracts and the surrounding tissue is the reverse of the contrast in water peak height images. This indicates the presence of a shoulder in

Sun, Ocean, Nuclear Bombs, and Fossil Fuels: Radiocarbon Variations and Implications for High-Resolution Dating

Science.gov (United States)

Dutta, Koushik

2016-06-01

Radiocarbon, or 14C, is a radiometric dating method ideally suited for providing a chronological framework in archaeology and geosciences for timescales spanning the last 50,000 years. 14C is easily detectable in most common natural organic materials and has a half-life (5,730±40 years) relevant to these timescales. 14C produced from large-scale detonations of nuclear bombs between the 1950s and the early 1960s can be used for dating modern organic materials formed after the 1950s. Often these studies demand high-resolution chronology to resolve ages within a few decades to less than a few years. Despite developments in modern, high-precision 14C analytical methods, the applicability of 14C in high-resolution chronology is limited by short-term variations in atmospheric 14C in the past. This article reviews the roles of the principal natural drivers (e.g., solar magnetic activity and ocean circulation) and the anthropogenic perturbations (e.g., fossil fuel CO2 and 14C from nuclear and thermonuclear bombs) that are responsible for short-term 14C variations in the environment. Methods and challenges of high-resolution 14C dating are discussed.

High-resolution room-temperature sample scanning superconducting quantum interference device microscope configurable for geological and biomagnetic applications

Science.gov (United States)

Fong, L. E.; Holzer, J. R.; McBride, K. K.; Lima, E. A.; Baudenbacher, F.; Radparvar, M.

2005-05-01

We have developed a scanning superconducting quantum interference device (SQUID) microscope system with interchangeable sensor configurations for imaging magnetic fields of room-temperature (RT) samples with submillimeter resolution. The low-critical-temperature (Tc) niobium-based monolithic SQUID sensors are mounted on the tip of a sapphire and thermally anchored to the helium reservoir. A 25μm sapphire window separates the vacuum space from the RT sample. A positioning mechanism allows us to adjust the sample-to-sensor spacing from the top of the Dewar. We achieved a sensor-to-sample spacing of 100μm, which could be maintained for periods of up to four weeks. Different SQUID sensor designs are necessary to achieve the best combination of spatial resolution and field sensitivity for a given source configuration. For imaging thin sections of geological samples, we used a custom-designed monolithic low-Tc niobium bare SQUID sensor, with an effective diameter of 80μm, and achieved a field sensitivity of 1.5pT/Hz1/2 and a magnetic moment sensitivity of 5.4×10-18Am2/Hz1/2 at a sensor-to-sample spacing of 100μm in the white noise region for frequencies above 100Hz. Imaging action currents in cardiac tissue requires a higher field sensitivity, which can only be achieved by compromising spatial resolution. We developed a monolithic low-Tc niobium multiloop SQUID sensor, with sensor sizes ranging from 250μm to 1mm, and achieved sensitivities of 480-180fT /Hz1/2 in the white noise region for frequencies above 100Hz, respectively. For all sensor configurations, the spatial resolution was comparable to the effective diameter and limited by the sensor-to-sample spacing. Spatial registration allowed us to compare high-resolution images of magnetic fields associated with action currents and optical recordings of transmembrane potentials to study the bidomain nature of cardiac tissue or to match petrography to magnetic field maps in thin sections of geological samples.

Development of dispersion interferometer for magnetic confinement plasmas and high-pressure plasmas

Science.gov (United States)

Akiyama, T.; Yasuhara, R.; Kawahata, K.; Nakayama, K.; Okajima, S.; Urabe, K.; Terashima, K.; Shirai, N.

2015-09-01

A CO2 laser dispersion interferometer (DI) has been developed for both magnetically fusion plasmas and high pressure industrial plasmas. The DI measures the phase shift caused by dispersion in a medium. Therefore, it is insensitive to the mechanical vibrations and changes in the neutral gas density, which degrade the resolution of the electron density measurement. We installed the DI on the Large Helical Device (LHD) and demonstrated a high density resolution of 2× 1017 m-3 without any vibration-free bench. The measured electron density with the DI shows good agreement with results of the existing far infrared laser (a wavelength of 119 μ m) interferometer. The DI system is also applied to the electron density measurement of high-pressure small-scale plasmas. The significant suppression of the phase shift caused by the neutral gas is proven. The achieved density resolution was 1.5× 1019 m-3 with a response time of 100 μ s. A shorter version of this contribution is due to be published in PoS at: 1st EPS conference on Plasma Diagnostics

Design of magnetic analysis system for magnetic proton recoil spectrometer

International Nuclear Information System (INIS)

Qi Jianmin; Jiang Shilun; Zhou Lin; Peng Taiping

2010-01-01

Magnetic proton recoil (MPR) spectrometer is a novel diagnostic instrument with high performance for measurements of the neutron spectra from inertial confinement fusion (ICF) experiments and high power fusion devices. The design of the magnetic analysis system, which is a key part of the compact MPR-type spectrometer, has been completed through two-dimensional beam transport simulations and three-dimensional particle transport simulation. The analysis of the system's parameters and performances was performed, as well as system designs based on preferential principles of energy resolution, detection efficiency, and count rate, respectively. The results indicate that the magnetic analysis system can achieve a detection efficiency of 10 -5 ∼ 10 -4 level at the resolution range of 1.5% to 3.0% and fulfill the design goals of the compact MPR spectrometer. (authors)

New high-resolution rocket-ultraviolet filtergrams of the solar disc

Science.gov (United States)

Foing, B.; Bonnet, R.-M.; Bruner, M.

1986-01-01

A rocket-borne solar ultraviolet telescope named Transition Region Camera was launched successfully for the third on July 13, 1982. High quality calibrated photographic images of the sun were obtained at Lyman alpha and in the continuum at 160 nm and 220 nm. The angular resolution achieved is better than one arcsec. A flare, active regions, sunspots, the 8 Mm mesostructure, the chromospheric network, bright UV grains and coronal loops were observed during the flight. The results are presented and the evolution with height in the solar atmosphere of the various structures observed is followed from one wavelength to the other, showing distinct differences. The value of the field's intensity of magnetic flux tubes is deduced from the observations.

Magnetic phase diagram of Ce2Fe17 under high pressures in high magnetic fields

International Nuclear Information System (INIS)

Ishikawa, Fumihiro; Goto, Tsuneaki; Fujii, Hironobu

2003-01-01

The magnetization of Ce 2 Fe 17 was precisely measured under high pressures up to 1.2 GPa in magnetic fields up to 18 T. The magnetic phase diagram in the B-T plane is determined at 0, 0.3, 0.4, 0.6, 0.9 and 1.2 GPa. At 0 GPa, five magnetic phases exist and the application of high pressure produces two additional magnetic phases. The shape of the phase diagram changes drastically with increasing pressure

High resolution data acquisition

Science.gov (United States)

Thornton, Glenn W.; Fuller, Kenneth R.

1993-01-01

A high resolution event interval timing system measures short time intervals such as occur in high energy physics or laser ranging. Timing is provided from a clock (38) pulse train (37) and analog circuitry (44) for generating a triangular wave (46) synchronously with the pulse train (37). The triangular wave (46) has an amplitude and slope functionally related to the time elapsed during each clock pulse in the train. A converter (18, 32) forms a first digital value of the amplitude and slope of the triangle wave at the start of the event interval and a second digital value of the amplitude and slope of the triangle wave at the end of the event interval. A counter (26) counts the clock pulse train (37) during the interval to form a gross event interval time. A computer (52) then combines the gross event interval time and the first and second digital values to output a high resolution value for the event interval.

High resolution time integration for Sn radiation transport

International Nuclear Information System (INIS)

Thoreson, Greg; McClarren, Ryan G.; Chang, Jae H.

2008-01-01

First order, second order and high resolution time discretization schemes are implemented and studied for the S n equations. The high resolution method employs a rate of convergence better than first order, but also suppresses artificial oscillations introduced by second order schemes in hyperbolic differential equations. All three methods were compared for accuracy and convergence rates. For non-absorbing problems, both second order and high resolution converged to the same solution as the first order with better convergence rates. High resolution is more accurate than first order and matches or exceeds the second order method. (authors)

Photo-magnetic imaging: resolving optical contrast at MRI resolution

International Nuclear Information System (INIS)

Lin Yuting; Thayer, David; Luk, Alex L; Gulsen, Gultekin; Gao Hao

2013-01-01

In this paper, we establish the mathematical framework of a novel imaging technique, namely photo-magnetic imaging (PMI). PMI uses a laser to illuminate biological tissues and measure the induced temperature variations using magnetic resonance imaging (MRI). PMI overcomes the limitation of conventional optical imaging and allows imaging of the optical contrast at MRI spatial resolution. The image reconstruction for PMI, using a finite-element-based algorithm with an iterative approach, is presented in this paper. The quantitative accuracy of PMI is investigated for various inclusion sizes, depths and absorption values. Then, a comparison between conventional diffuse optical tomography (DOT) and PMI is carried out to illustrate the superior performance of PMI. An example is presented showing that two 2 mm diameter inclusions embedded 4.5 mm deep and located side by side in a 25 mm diameter circular geometry medium are recovered as a single 6 mm diameter object with DOT. However, these two objects are not only effectively resolved with PMI, but their true concentrations are also recovered successfully. (paper)

Development of Nb nanoSQUIDs based on SNS junctions for operation in high magnetic fields

Energy Technology Data Exchange (ETDEWEB)

Morosh, Viacheslav; Kieler, Oliver; Weimann, Thomas; Zorin, Alexander [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (Germany); Mueller, Benedikt; Martinez-Perez, Maria Jose; Kleiner, Reinhold; Koelle, Dieter [Physikalisches Institut and Center for Quantum Science in LISA+, Universitaet Tuebingen (Germany)

2016-07-01

Investigation of the magnetization reversal of single magnetic nanoparticles requires SQUIDs with high spatial resolution, high spin sensitivity (a few Bohr magneton μ{sub B}) and at the same time sufficient stability in high magnetic fields. We fabricated dc nanoSQUIDs comprising overdamped SNS sandwich-type (Nb/HfTi/Nb) Josephson junctions using optimized technology based on combination of electron beam lithography and chemical-mechanical polishing. Our nanoSQUIDs have Josephson junctions with lateral dimensions ≤ 150 nm x 150 nm, effective loop areas < 0.05 μm{sup 2} and the distance between the Josephson junctions ≤ 100 nm. The feeding strip lines of the width ≤ 200 nm have been realized. The nanoSQUIDs have shown stable operation in external magnetic fields at least up to 250 mT. Sufficiently low level of flux noise resulting in spin sensitivity of few tens μ{sub B}/Hz{sup 1/2} has been demonstrated. A further reduction of the nanoSQUID size using our technology is possible.

Symptomatic isolated middle cerebral artery dissection: High resolution MR findings

Energy Technology Data Exchange (ETDEWEB)

Byon, Jung Hee; Kwak, Hyo Sung; Chung, Gyung Ho; Hwang, Seung Bae [Dept. of Radiology, Chonbuk National University Medical School, Jeonju (Korea, Republic of)

2015-11-15

To perform high-resolution magnetic resonance imaging (HRMRI) and determine clinical features of patients with acute symptomatic middle cerebral artery (MCA) dissection. Thirteen patients with acute symptomatic MCA dissection underwent HRMRI within 3 days after initial clinical onset. They also underwent routine brain MR imaging. HRMRI examinations included time-of-flight MR angiography (MRA), T2-weighted, T1-weighted, proton-density-weighted, and three-dimensional magnetization-prepared rapid acquisition gradient-echo (MPRAGE) sequences. Conventional angiography and MRA were used as reference standard to establish the diagnosis of MCA dissection. The angiographic findings and HRMRI findings such as intimal flap, double lumen, and intramural hematoma were analyzed in this study. All patients presented cerebral ischemia (median National Institutes of Health Stroke Scale score = 4, range = 0-18). String sign was seen on MRA in seven patients. However, double lumen was seen in all patients on HRMRI by intimal flap. High signal lesion on MPRAGE sequences around the dissection lumen due to intramural hematoma was seen in three patients. HRMRI can be used to easily detect the wall structure of MCA such as the intimal flap and double lumen in patients with acute symptomatic MCA dissection. MPRAGE can detect hemorrhage in false lumen of MCA dissection.

Advances in the staging of renal cell carcinoma with high-resolution imaging

International Nuclear Information System (INIS)

Hallscheidt, P.; Noeldge, G.; Schawo, S.; Kauffmann, G.; Palmowski, M.; Bartling, S.; Pfitzenmaier, J.

2007-01-01

Modern imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI) allow high-resolution imaging of the abdomen. Modern scanners made high temporal as well as high spatial resolution available. Therapeutic approaches to the treatment of renal cell carcinoma have been improved over the recent years. Besides conventional and open laparoscopic tumor nephrectomy and nephron sparing, surgical approaches such as local tumor cryotherapy and radiofrequency ablation (RF) are ablative modalities and are used increasingly. Improved anesthesiological methods and new surgical approaches also allow curative treatment in extended tumors. Prerequisites for preoperative imaging modalities include visualization of the kidney tumor as well as its staging. Tumor-related infiltration of the renal pelvis or invasion of the perinephric fat and the renal hilus has to be excluded prior to nephron sparing surgery. In cases with extended tumors with infiltration of the inferior vena cava, it is necessary to visualize the exact extension of the tumor growth towards the right atrium in the vena cava. The radiologist should be informed about the diagnostic possibilities and limitations of the imaging modalities of CT and MRI in order to support the urologist in the planning and performance of surgical therapeutical approaches. (orig.)

Nitrogen detected TROSY at high field yields high resolution and sensitivity for protein NMR

International Nuclear Information System (INIS)

Takeuchi, Koh; Arthanari, Haribabu; Shimada, Ichio; Wagner, Gerhard

2015-01-01

Detection of 15 N in multidimensional NMR experiments of proteins has sparsely been utilized because of the low gyromagnetic ratio (γ) of nitrogen and the presumed low sensitivity of such experiments. Here we show that selecting the TROSY components of proton-attached 15 N nuclei (TROSY 15 N H ) yields high quality spectra in high field magnets (>600 MHz) by taking advantage of the slow 15 N transverse relaxation and compensating for the inherently low 15 N sensitivity. The 15 N TROSY transverse relaxation rates increase modestly with molecular weight but the TROSY gain in peak heights depends strongly on the magnetic field strength. Theoretical simulations predict that the narrowest line width for the TROSY 15 N H component can be obtained at 900 MHz, but sensitivity reaches its maximum around 1.2 GHz. Based on these considerations, a 15 N-detected 2D 1 H– 15 N TROSY-HSQC ( 15 N-detected TROSY-HSQC) experiment was developed and high-quality 2D spectra were recorded at 800 MHz in 2 h for 1 mM maltose-binding protein at 278 K (τ c  ∼ 40 ns). Unlike for 1 H detected TROSY, deuteration is not mandatory to benefit 15 N detected TROSY due to reduced dipolar broadening, which facilitates studies of proteins that cannot be deuterated, especially in cases where production requires eukaryotic expression systems. The option of recording 15 N TROSY of proteins expressed in H 2 O media also alleviates the problem of incomplete amide proton back exchange, which often hampers the detection of amide groups in the core of large molecular weight proteins that are expressed in D 2 O culture media and cannot be refolded for amide back exchange. These results illustrate the potential of 15 N H -detected TROSY experiments as a means to exploit the high resolution offered by high field magnets near and above 1 GHz

High-resolution 3-T MR neurography of peroneal neuropathy

International Nuclear Information System (INIS)

Chhabra, Avneesh; Faridian-Aragh, Neda; Chalian, Majid; Soldatos, Theodoros; Thawait, Shrey K.; Williams, Eric H.; Andreisek, Gustav

2012-01-01

The common peroneal nerve (CPN), a major terminal branch of the sciatic nerve, can be subject to a variety of pathologies, which may affect the nerve at any level from the lumbar plexus to its distal branches. Although the diagnosis of peripheral neuropathy is traditionally based on a patient's clinical findings and electrodiagnostic tests, magnetic resonance neurography (MRN) is gaining an increasing role in the definition of the type, site, and extent of peripheral nerve disorders. Current high-field MR scanners enable high-resolution and excellent soft-tissue contrast imaging of peripheral nerves. In the lower extremities, MR neurography has been employed in the demonstration of the anatomy and pathology of the CPN, as well as in the detection of associated secondary muscle denervation changes. This article reviews the normal appearance of the CPN as well as typical pathologies and abnormal findings at 3.0-T MR neurography of the lower extremity. (orig.)

High-resolution 3-T MR neurography of peroneal neuropathy

Energy Technology Data Exchange (ETDEWEB)

Chhabra, Avneesh; Faridian-Aragh, Neda; Chalian, Majid; Soldatos, Theodoros; Thawait, Shrey K. [Johns Hopkins Hospital, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Williams, Eric H. [Johns Hopkins Hospital, Department of Plastic Surgery, Baltimore, MD (United States); Dellon Institute for Peripheral Nerve Surgery, Baltimore, MD (United States); Andreisek, Gustav [University Hospital Zurich, Institute for Diagnostic Radiology, Department of Medical Radiology, Zurich (Switzerland)

2012-03-15

The common peroneal nerve (CPN), a major terminal branch of the sciatic nerve, can be subject to a variety of pathologies, which may affect the nerve at any level from the lumbar plexus to its distal branches. Although the diagnosis of peripheral neuropathy is traditionally based on a patient's clinical findings and electrodiagnostic tests, magnetic resonance neurography (MRN) is gaining an increasing role in the definition of the type, site, and extent of peripheral nerve disorders. Current high-field MR scanners enable high-resolution and excellent soft-tissue contrast imaging of peripheral nerves. In the lower extremities, MR neurography has been employed in the demonstration of the anatomy and pathology of the CPN, as well as in the detection of associated secondary muscle denervation changes. This article reviews the normal appearance of the CPN as well as typical pathologies and abnormal findings at 3.0-T MR neurography of the lower extremity. (orig.)

High-resolution multi-slice PET

International Nuclear Information System (INIS)

Yasillo, N.J.; Chintu Chen; Ordonez, C.E.; Kapp, O.H.; Sosnowski, J.; Beck, R.N.

1992-01-01

This report evaluates the progress to test the feasibility and to initiate the design of a high resolution multi-slice PET system. The following specific areas were evaluated: detector development and testing; electronics configuration and design; mechanical design; and system simulation. The design and construction of a multiple-slice, high-resolution positron tomograph will provide substantial improvements in the accuracy and reproducibility of measurements of the distribution of activity concentrations in the brain. The range of functional brain research and our understanding of local brain function will be greatly extended when the development of this instrumentation is completed

High resolution NMR spectroscopy of synthetic polymers in bulk

International Nuclear Information System (INIS)

Komorski, R.A.

1986-01-01

The contents of this book are: Overview of high-resolution NMR of solid polymers; High-resolution NMR of glassy amorphous polymers; Carbon-13 solid-state NMR of semicrystalline polymers; Conformational analysis of polymers of solid-state NMR; High-resolution NMR studies of oriented polymers; High-resolution solid-state NMR of protons in polymers; and Deuterium NMR of solid polymers. This work brings together the various approaches for high-resolution NMR studies of bulk polymers into one volume. Heavy emphasis is, of course, given to 13C NMR studies both above and below Tg. Standard high-power pulse and wide-line techniques are not covered

Competing orbital ordering in RVO3 compounds: High-resolution x-ray diffraction and thermal expansion

International Nuclear Information System (INIS)

Sage, M. H.; Blake, G. R.; Palstra, T. T. M.; Marquina, C.

2007-01-01

We report evidence for the phase coexistence of orbital orderings of different symmetry in RVO 3 compounds with intermediate-size rare earths. Through a study by high-resolution x-ray powder diffraction and thermal expansion, we show that the competing orbital orderings are associated with the magnitude of the VO 6 octahedral tilting and magnetic exchange striction in these compounds and that the phase-separated state is stabilized by lattice strains

High resolution anatomical and quantitative MRI of the entire human occipital lobe ex vivo at 9.4 T

NARCIS (Netherlands)

Sengupta, S.; Lagos Fritz, F.J.; Harms, R.L.; Hildebrand, S.; Tse, D.H.Y.; Poser, B.A.; Goebel, R.; Roebroeck, A.

Several magnetic resonance imaging (MRI) contrasts are sensitive to myelin content in gray matter in vivo which has ignited ambitions of MRI-based in vivo cortical histology. Ultra-high field (UHF) MRI, at fields of 7 T and beyond, is crucial to provide the resolution and contrast needed to sample

High resolution integral holography using Fourier ptychographic approach.

Science.gov (United States)

Li, Zhaohui; Zhang, Jianqi; Wang, Xiaorui; Liu, Delian

2014-12-29

An innovative approach is proposed for calculating high resolution computer generated integral holograms by using the Fourier Ptychographic (FP) algorithm. The approach initializes a high resolution complex hologram with a random guess, and then stitches together low resolution multi-view images, synthesized from the elemental images captured by integral imaging (II), to recover the high resolution hologram through an iterative retrieval with FP constrains. This paper begins with an analysis of the principle of hologram synthesis from multi-projections, followed by an accurate determination of the constrains required in the Fourier ptychographic integral-holography (FPIH). Next, the procedure of the approach is described in detail. Finally, optical reconstructions are performed and the results are demonstrated. Theoretical analysis and experiments show that our proposed approach can reconstruct 3D scenes with high resolution.

Development of high field superconducting magnet

International Nuclear Information System (INIS)

Irie, Fujio; Takeo, Masakatsu.

1986-01-01

Recently, in connection with nuclear fusion research, the development of high field superconducting magnets showed rapid progress. The development of high field magnets of 15 T class by the techniques of winding after heat treatment has been continued in various places, as these techniques are suitable to make large magnets. In 1985, Kyushu University attained the record of 15.5 T. However in high field magnets, there are many problems peculiar to them, and the basic research related to those is demanded. In this report, these general problems, the experience of the design and manufacture in Kyushu University and the related problems are described. The superconducting magnet installed in the Superconducting Magnet Research Center of Kyushu University attained the record of 15.5 T for the first time in March, 1985. In superconducting magnets, very difficult problem must be solved since superconductivity, heat and mechanical force are inter related. The problems of the wire materials for high field, the scale of high field magnets, the condition limiting mean current density, and the development of high field magnets in Kyushu University are described. (Kako, I.)

High-resolution thermal expansion measurements under helium-gas pressure

Science.gov (United States)

Manna, Rudra Sekhar; Wolf, Bernd; de Souza, Mariano; Lang, Michael

2012-08-01

We report on the realization of a capacitive dilatometer, designed for high-resolution measurements of length changes of a material for temperatures 1.4 K ⩽ T ⩽ 300 K and hydrostatic pressure P ⩽ 250 MPa. Helium (4He) is used as a pressure-transmitting medium, ensuring hydrostatic-pressure conditions. Special emphasis has been given to guarantee, to a good approximation, constant-pressure conditions during temperature sweeps. The performance of the dilatometer is demonstrated by measurements of the coefficient of thermal expansion at pressures P ≃ 0.1 MPa (ambient pressure) and 104 MPa on a single crystal of azurite, Cu3(CO3)2(OH)2, a quasi-one-dimensional spin S = 1/2 Heisenberg antiferromagnet. The results indicate a strong effect of pressure on the magnetic interactions in this system.

New GOES High-Resolution Magnetic Measurements and their Contribution to Understanding Magnetospheric Particle Dynamics

Science.gov (United States)

Redmon, R. J.; Loto'aniu, P. T. M.; Boudouridis, A.; Chi, P. J.; Singer, H. J.; Kress, B. T.; Rodriguez, J. V.; Abdelqader, A.; Tilton, M.

2017-12-01

The era of NOAA observations of the geomagnetic field started with SMS-1 in May 1974 and continues to this day with GOES-13-16 (on-orbit). We describe the development of a new 20+ year archive of science-quality, high-cadence geostationary measurements of the magnetic field from eight NOAA spacecraft (GOES-8 through GOES-15), the status of GOES-16 and new scientific results using these data. GOES magnetic observations provide an early warning of impending space weather, are the core geostationary data set used for the construction of magnetospheric magnetic models, and can be used to estimate electromagnetic wave power in frequency bands important for plasma processes. Many science grade improvements are being made across the GOES archive to unify the format and content from GOES-8 through the new GOES-R series (with the first of that series launched on November 19, 2016). A majority of the 2-Hz magnetic observations from GOES-8-12 have never before been publicly accessible due to processing constraints. Now, a NOAA Big Earth Data Initiative project is underway to process these measurements starting from original telemetry records. Overall the new archive will include vector measurements in geophysically relevant coordinates (EPN, GSM, and VDH), comprehensive documentation, highest temporal cadence, best calibration parameters, recomputed means, updated quality flagging, full spacecraft ephemeris information, a unified standard format and public access. We are also developing spectral characterization tools for estimating power in standard frequency bands (up to 1 Hz for G8-15), and detecting ULF waves related to field-line resonances. We present the project status and findings, including in-situ statistical and extreme ULF event properties, and case studies where the ULF oscillations along the same field line were observed simultaneously by GOES near the equator in the magnetosphere, the ST-5 satellites at low altitudes, and ground magnetometer stations. For event

High-spatial resolution and high-spectral resolution detector for use in the measurement of solar flare hard x rays

International Nuclear Information System (INIS)

Desai, U.D.; Orwig, L.E.

1988-01-01

In the areas of high spatial resolution, the evaluation of a hard X-ray detector with 65 micron spatial resolution for operation in the energy range from 30 to 400 keV is proposed. The basic detector is a thick large-area scintillator faceplate, composed of a matrix of high-density scintillating glass fibers, attached to a proximity type image intensifier tube with a resistive-anode digital readout system. Such a detector, combined with a coded-aperture mask, would be ideal for use as a modest-sized hard X-ray imaging instrument up to X-ray energies as high as several hundred keV. As an integral part of this study it was also proposed that several techniques be critically evaluated for X-ray image coding which could be used with this detector. In the area of high spectral resolution, it is proposed to evaluate two different types of detectors for use as X-ray spectrometers for solar flares: planar silicon detectors and high-purity germanium detectors (HPGe). Instruments utilizing these high-spatial-resolution detectors for hard X-ray imaging measurements from 30 to 400 keV and high-spectral-resolution detectors for measurements over a similar energy range would be ideally suited for making crucial solar flare observations during the upcoming maximum in the solar cycle

Conclusion: probable and possible futures. MRI with ultra high magnetic field

International Nuclear Information System (INIS)

Le Bihan, D.

2009-01-01

MR neuroimaging does not interfere with brain function. Because it is safe, it can be used to study the brains of both patients and healthy volunteers. The tasks performed by neurons depend largely on their precise location, and high-field magnets have the potential to provide a 5- to 10-fold increase in spatio-temporal resolution. This should allow brain function to be studied on a scale of only a few thousand neurons, possibly at the intermediate scale of the 'neural code'. NeuroSpin, a new CEA research center, is dedicated to neuro-MRI at high magnetic field strengths. As a forum for dialogue between those developing and those using these instruments, it brings together researchers and engineers, technicians and medical doctors. NeuroSpin is one of the few institutions in Europe, if not the world, where these experts can come together in one place to design, construct and use machines equipped with ultra-strong magnets. The strongest 'routine' MR device currently operates at 3 Tesla (60 000 times the earth's magnetic field), whereas a first French system operating at 7 Tesla (140 000 times the earth's field) is now available for human studies, and another system operating at 11.7 Tesla (world record) should be delivered in 2011. Preclinical studies are also being conducted with magnets operating at 7 Tesla and, soon, 17.6 Tesla. (author)

Magnetic resonance annual 1986

International Nuclear Information System (INIS)

Kressel, H.Y.

1986-01-01

This book contains papers written on magnetic resonance during 1986. Topics include: musculosketetal magnetic resonance imaging; imaging of the spine; magnetic resonance chemical shift imaging; magnetic resonance imaging in the central nervous system; comparison to computed tomography; high resolution magnetic resonance imaging using surface coils; magnetic resonance imaging of the chest; magnetic resonance imaging of the breast; magnetic resonance imaging of the liver; magnetic resonance spectroscopy of neoplasms; blood flow effects in magnetic resonance imaging; and current and potential applications of clinical sodium magnetic resonance imaging

Micromagnetism and the microstructure of high-temperature permanent magnets

International Nuclear Information System (INIS)

Goll, D.; Kronmueller, H.; Stadelmaier, H.H.

2004-01-01

Sm 2 (Co,Cu,Fe,Zr) 17 permanent magnets with their three-phase precipitation structure (cells, cell walls, and lamellae) show two characteristic features which so far are difficult to interpret but which are the prerequisites for high-temperature applications: (1) The hard magnetic properties only develop during the final step of the three-step annealing procedure consisting of homogenization, isothermal aging, and cooling. (2) Depending on the composition and on the annealing parameters, the temperature dependence of the coercivity can be easily changed from the conventional monotonic to the recent nonmonotonic behavior showing coercivities up to 1 T even at 500 K. The magnetic hardening during cooling is due to the fact that the cell walls order chemically and structurally during the cooling process. From an analysis of electron diffraction patterns of the superimposed structures existing before and after cooling it could be proven that a phase transition from a phase mixture of defective phases 2:17, 2:7, and 5:19 to the ordered 1:5 phase takes place in the cell walls during cooling. The nonmonotonic temperature dependence of the coercivity is narrowly related to the magnetic hardening mechanism which can be either pinning or nucleation and results from the magnetic and microstructural properties of the cell walls. These properties have been determined quantitatively from hysteresis loop measurements and from high-resolution transmission electron microscopy and energy dispersive x-ray analysis. Due to the temperature dependence of the intrinsic magnetic properties, the nonmonotonic temperature dependence of the coercivity is found to be determined by repulsive pinning of domain walls at the cell walls at low temperatures, by attractive pinning of domain walls in the cell walls at intermediate temperatures, and by nucleation at high temperatures. This complex temperature behavior is also reflected in characteristic changes of the angular dependence of the

Evaluation of Composite Wire Ropes Using Unsaturated Magnetic Excitation and Reconstruction Image with Super-Resolution

Directory of Open Access Journals (Sweden)

Xiaojiang Tan

2018-05-01

Full Text Available Estimating the exact residual lifetime of wire rope involves the security of industry manufacturing, mining, tourism, and so on. In this paper, a novel testing technology was developed based on unsaturated magnetic excitation, and a fabricating prototype overcame the shortcomings of traditional detection equipment in terms of volume, sensibility, reliability, and weight. Massive artificial discontinuities were applied to examine the effectiveness of this new technology with a giant magneto resistance(GMR sensor array, which included types of small gaps, curling wires, wide fractures, and abrasion. A resolution enhancement method, which was adopted for multiframe images, was proposed for promoting magnetic flux leakage images of a few sensors. Characteristic vectors of statistics and geometry were extracted, then we applied a radial basis function neural network to achieve a quantitative recognition rate of 91.43% with one wire-limiting error. Experimental results showed that the new device can detect defects in various types of wire rope and prolong the service life with high lift-off distance and high reliability, and the system could provide useful options to evaluate the lifetime of wire rope.

Development of a high energy resolution magnetic bolometer for the determination of photon emission intensities by gamma-ray spectrometry

International Nuclear Information System (INIS)

Rodrigues, M.

2007-12-01

In this research thesis, a first chapter describes the metrological difficulties for the determination of radionuclide photon emission intensities. Then, it discusses the understanding and the required tools for the computing of a magnetic bolometer signal with respect to the different operation parameters and to the sensor geometry. The author describes the implementation of the experimental device and its validation with a first sensor. The new sensor is then optimised for the measurement of photon emission intensities with a good efficiency and a theoretical energy resolution less than 100 eV up to 200 keV. The sensor's detection efficiency and operation have been characterized with a 133 Ba source. The author finally presents the obtained results

Estimation of residual stress in cold rolled iron-disks from strain measurements on the high resolution Fourier diffractometer

International Nuclear Information System (INIS)

Aksenov, V.L.; Balagurov, A.M.; Taran, Yu.V.

1995-01-01

The results of estimating residual stresses in cold rolled iron disks by measurements with the high resolution Fourier diffractometer (HRFD) at the IBR-2 pulsed reactor are presented. These measurements were made for calibration of magnetic and ultrasonic measurements carried out at the Fraunhofer-Institute for Nondestructive Testing in Saarbrucken (Germany). The tested objects were cold rolled steel disks of 2.5 mm thickness and diameter of about 500 mm used for forming small, gas pressure tanks. Neutron diffraction experiments were carried out at the scattering angle 2θ=+152 d eg with resolution Δd/d=1.5·10 -3 . The gauge volume was chosen according to the magnetic measurements lateral resolution 20x20 mm 2 . In the nearest future the neutron diffraction measurements with cold rolled iron disks at the scattering angle 2θ=±90 0 are planned. Also the texture analysis will be included in the Rietveld refinement procedure for more correct calculation of residual stress fields in the cold rolled materials. 8 refs., 10 figs., 1 tab

SIEMENS ADVANCED QUANTRA FTICR MASS SPECTROMETER FOR ULTRA HIGH RESOLUTION AT LOW MASS

Energy Technology Data Exchange (ETDEWEB)

Spencer, W; Laura Tovo, L

2008-07-08

The Siemens Advanced Quantra Fourier Transform Ion Cyclotron Resonance (FTICR) mass spectrometer was evaluated as an alternative instrument to large double focusing mass spectrometers for gas analysis. High resolution mass spectrometers capable of resolving the common mass isomers of the hydrogen isotopes are used to provide data for accurate loading of reservoirs and to monitor separation of tritium, deuterium, and helium. Conventional double focusing magnetic sector instruments have a resolution that is limited to about 5000. The Siemens FTICR instrument achieves resolution beyond 400,000 and could possibly resolve the tritium ion from the helium-3 ion, which differ by the weight of an electron, 0.00549 amu. Working with Y-12 and LANL, SRNL requested Siemens to modify their commercial Quantra system for low mass analysis. To achieve the required performance, Siemens had to increase the available waveform operating frequency from 5 MHz to 40 MHz and completely redesign the control electronics and software. However, they were able to use the previous ion trap, magnet, passive pump, and piezo-electric pulsed inlet valve design. NNSA invested $1M in this project and acquired four systems, two for Y-12 and one each for SRNL and LANL. Siemens claimed a $10M investment in the Quantra systems. The new Siemens Advanced Quantra demonstrated phenomenal resolution in the low mass range. Resolution greater than 400,000 was achieved for mass 2. The new spectrometer had a useful working mass range to 500 Daltons. However, experiments found that a continuous single scan from low mass to high was not possible. Two useful working ranges were established covering masses 1 to 6 and masses 12 to 500 for our studies. A compromise performance condition enabled masses 1 to 45 to be surveyed. The instrument was found to have a dynamic range of about three orders of magnitude and quantitative analysis is expected to be limited to around 5 percent without using complex fitting algorithms

The appearances of oesophageal carcinoma demonstrated on high-resolution, T2-weighted MRI, with histopathological correlation

International Nuclear Information System (INIS)

Riddell, A.M.; Allum, W.H.; Thompson, J.N.; Wotherspoon, A.C.; Richardson, C.; Brown, G.

2007-01-01

This paper describes the spectrum of imaging features of oesophageal adenocarcinoma seen using high-resolution T2-weighted (T2W) magnetic resonance imaging (MRI). Thirty-nine patients with biopsy-proven oesophageal adenocarcinoma were scanned using an external surface coil. A sagittal T2W sequence was used to localise the tumour and to plan axial images perpendicular to the tumour. Fast spin-echo (FSE) T2W axial sequence parameters were: TR/TE, 3,300-5,000 ms/120-80 ms; field of view (FOV) 225 mm, matrix 176 x 512(reconstructed) mm to 256 x 224 mm, giving an in-plane resolution of between 1.28 x 0.44 mm and 0.88 x 1.00 mm, with 3-mm slice thickness. Thirty-three patients underwent resection and the MR images were compared with the histological whole-mount sections. There were four T1, 12 T2, and 17 T3 tumours. The T2W high-resolution MRI sequences produced detailed images of the oesophageal wall and surrounding structures. Analysis of the imaging appearances for different tumour T stages enabled the development of imaging criteria for local staging of oesophageal cancer using high-resolution MRI. Our study illustrates the spectrum of appearances of oesophageal cancer on T2W high-resolution MRI, and using the criteria established in this study, demonstrates the potential of this technique as an alternative non-invasive method for local staging for oesophageal cancer. (orig.)

High energy magnetic excitations

International Nuclear Information System (INIS)

Endoh, Yasuo

1988-01-01

The report emphasizes that the current development in condensed matter physics opens a research field fit to inelastic neutron scattering experiments in the eV range which is easilly accessed by spallation neutron sources. Several important subjects adopted at thermal reactors are shown. It is desired to extend the implementation of the spectroscopic experiments for investigation of higher energy magnetic excitations. For La 2 CuO 4 , which is the mother crystal of the first high Tc materials found by Bednortz and Muller, it seems to be believed that the magnetism is well characterized by the two-dimensional Heisenberg antiferromagnetic Hamiltonian, and it is widely accepted that the magnetism is a most probable progenitor of high Tc superconductors. The unusual properties of spin correlations in this crystal have been studied extensively by standard neutron scattering techniques with steady neutrons at BNL. FeSi is not ordered magnetically but shows a very unique feature of temperature induced magnetism, which also has been studied extensively by using the thermal neutron scattering technique at BNL. In these experiments, polarized neutrons are indispensable to extract the clean magnetic components out of other components of non-magnetic scattering. (N.K.)

High-resolution MR imaging for dental impressions: a feasibility study.

Science.gov (United States)

Boldt, Julian; Rottner, Kurt; Schmitter, Marc; Hopfgartner, Andreas; Jakob, Peter; Richter, Ernst-Jürgen; Tymofiyeva, Olga

2018-04-01

Magnetic resonance imaging is an emerging technology in dental medicine. While low-resolution MRI has especially provided means to examine the temporomandibular joint due to its anatomic inaccessibility, it was the goal of this study to assess whether high-resolution MRI is capable of delivering a dataset sufficiently precise enough to serve as digital impression of human teeth. An informed and consenting patient in need of dental restoration with fixed partial dentures was chosen as subject. Two prepared teeth were measured using MRI and the dataset subjected to mathematical processing before Fourier transformation. After reconstruction, a 3D file was generated which was fed into an existing industry standard CAD/CAM process. A framework for a fixed dental prosthesis was digitally modeled and manufactured by laser-sintering. The fit in situ was found to be acceptable by current clinical standards, which allowed permanent placement of the fixed prosthesis. Using a clinical whole-body MR scanner with the addition of custom add-on hardware, contrast enhancement, and data post-processing, resolution and signal-to-noise ratio were sufficiently achieved to allow fabrication of a dental restoration in an acquisition time comparable to the setting time of common dental impression materials. Furthermore, the measurement was well tolerated. The herein described method can be regarded as proof of principle that MRI is a promising option for digital impressions when fixed partial dentures are required.

High-resolution regional climate model evaluation using variable-resolution CESM over California

Science.gov (United States)

Huang, X.; Rhoades, A.; Ullrich, P. A.; Zarzycki, C. M.

2015-12-01

Understanding the effect of climate change at regional scales remains a topic of intensive research. Though computational constraints remain a problem, high horizontal resolution is needed to represent topographic forcing, which is a significant driver of local climate variability. Although regional climate models (RCMs) have traditionally been used at these scales, variable-resolution global climate models (VRGCMs) have recently arisen as an alternative for studying regional weather and climate allowing two-way interaction between these domains without the need for nudging. In this study, the recently developed variable-resolution option within the Community Earth System Model (CESM) is assessed for long-term regional climate modeling over California. Our variable-resolution simulations will focus on relatively high resolutions for climate assessment, namely 28km and 14km regional resolution, which are much more typical for dynamically downscaled studies. For comparison with the more widely used RCM method, the Weather Research and Forecasting (WRF) model will be used for simulations at 27km and 9km. All simulations use the AMIP (Atmospheric Model Intercomparison Project) protocols. The time period is from 1979-01-01 to 2005-12-31 (UTC), and year 1979 was discarded as spin up time. The mean climatology across California's diverse climate zones, including temperature and precipitation, is analyzed and contrasted with the Weather Research and Forcasting (WRF) model (as a traditional RCM), regional reanalysis, gridded observational datasets and uniform high-resolution CESM at 0.25 degree with the finite volume (FV) dynamical core. The results show that variable-resolution CESM is competitive in representing regional climatology on both annual and seasonal time scales. This assessment adds value to the use of VRGCMs for projecting climate change over the coming century and improve our understanding of both past and future regional climate related to fine

Section on High Resolution Optical Imaging (HROI)

Data.gov (United States)

Federal Laboratory Consortium — The Section on High Resolution Optical Imaging (HROI) develops novel technologies for studying biological processes at unprecedented speed and resolution. Research...

Evaluation of toxicological effects induced by tributyltin in clam Ruditapes decussatus using high-resolution magic angle spinning nuclear magnetic resonance spectroscopy: Study of metabolic responses in heart tissue and detection of a novel metabolite

OpenAIRE

Hanana, H.; Simon, G.; Kervarec, N.; Cérantola, S.

2014-01-01

Tributyltin (TBT) is a highly toxic pollutant present in many aquatic ecosystems. Its toxicity in mollusks strongly affects their performance and survival. The main purpose of this study was to elucidate the mechanisms of TBT toxicity in clam Ruditapes decussatus by evaluating the metabolic responses of heart tissues, using high-resolution magic angle-spinning nuclear magnetic resonance (HRMAS NMR), after exposure to TBT (10−9, 10−6 and 10−4 M) during 24 h and 72 h. Results show that response...

Scanning SQUID susceptometers with sub-micron spatial resolution

Energy Technology Data Exchange (ETDEWEB)

Kirtley, John R., E-mail: jkirtley@stanford.edu; Rosenberg, Aaron J.; Palmstrom, Johanna C.; Holland, Connor M.; Moler, Kathryn A. [Department of Applied Physics, Stanford University, Stanford, California 94305-4045 (United States); Paulius, Lisa [Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008-5252 (United States); Spanton, Eric M. [Department of Physics, Stanford University, Stanford, California 94305-4045 (United States); Schiessl, Daniel [Attocube Systems AG, Königinstraße 11A, 80539 Munich (Germany); Jermain, Colin L.; Gibbons, Jonathan [Department of Physics, Cornell University, Cornell, Ithaca, New York 14853 (United States); Fung, Y.-K.K.; Gibson, Gerald W. [IBM Research Division, T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Huber, Martin E. [Department of Physics, University of Colorado Denver, Denver, Colorado 80217-3364 (United States); Ralph, Daniel C. [Department of Physics, Cornell University, Cornell, Ithaca, New York 14853 (United States); Kavli Institute at Cornell, Ithaca, New York 14853 (United States); Ketchen, Mark B. [OcteVue, Hadley, Massachusetts 01035 (United States)

2016-09-15

Superconducting QUantum Interference Device (SQUID) microscopy has excellent magnetic field sensitivity, but suffers from modest spatial resolution when compared with other scanning probes. This spatial resolution is determined by both the size of the field sensitive area and the spacing between this area and the sample surface. In this paper we describe scanning SQUID susceptometers that achieve sub-micron spatial resolution while retaining a white noise floor flux sensitivity of ≈2μΦ{sub 0}/Hz{sup 1/2}. This high spatial resolution is accomplished by deep sub-micron feature sizes, well shielded pickup loops fabricated using a planarized process, and a deep etch step that minimizes the spacing between the sample surface and the SQUID pickup loop. We describe the design, modeling, fabrication, and testing of these sensors. Although sub-micron spatial resolution has been achieved previously in scanning SQUID sensors, our sensors not only achieve high spatial resolution but also have integrated modulation coils for flux feedback, integrated field coils for susceptibility measurements, and batch processing. They are therefore a generally applicable tool for imaging sample magnetization, currents, and susceptibilities with higher spatial resolution than previous susceptometers.

Scanning SQUID susceptometers with sub-micron spatial resolution

International Nuclear Information System (INIS)

Kirtley, John R.; Rosenberg, Aaron J.; Palmstrom, Johanna C.; Holland, Connor M.; Moler, Kathryn A.; Paulius, Lisa; Spanton, Eric M.; Schiessl, Daniel; Jermain, Colin L.; Gibbons, Jonathan; Fung, Y.-K.K.; Gibson, Gerald W.; Huber, Martin E.; Ralph, Daniel C.; Ketchen, Mark B.

2016-01-01

Superconducting QUantum Interference Device (SQUID) microscopy has excellent magnetic field sensitivity, but suffers from modest spatial resolution when compared with other scanning probes. This spatial resolution is determined by both the size of the field sensitive area and the spacing between this area and the sample surface. In this paper we describe scanning SQUID susceptometers that achieve sub-micron spatial resolution while retaining a white noise floor flux sensitivity of ≈2μΦ_0/Hz"1"/"2. This high spatial resolution is accomplished by deep sub-micron feature sizes, well shielded pickup loops fabricated using a planarized process, and a deep etch step that minimizes the spacing between the sample surface and the SQUID pickup loop. We describe the design, modeling, fabrication, and testing of these sensors. Although sub-micron spatial resolution has been achieved previously in scanning SQUID sensors, our sensors not only achieve high spatial resolution but also have integrated modulation coils for flux feedback, integrated field coils for susceptibility measurements, and batch processing. They are therefore a generally applicable tool for imaging sample magnetization, currents, and susceptibilities with higher spatial resolution than previous susceptometers.

A high-resolution, 60 kyr record of the relative geomagnetic field intensity from Lake Towuti, Indonesia

Science.gov (United States)

Kirana, Kartika Hajar; Bijaksana, Satria; King, John; Tamuntuan, Gerald Hendrik; Russell, James; Ngkoimani, La Ode; Dahrin, Darharta; Fajar, Silvia Jannatul

2018-02-01

Past changes in the Earth's magnetic field can be highlighted through reconstructions of magnetic paleointensity. Many magnetic field variation features are global, and can be used for the detailed correlation and dating of sedimentary records. On the other hand, sedimentary magnetic records also exhibit features on a regional, rather than a global scale. Therefore, the development of regional scale magnetic field reconstructions is necessary to optimize magnetic paleointensity dating. In this paper, a 60 thousand year (kyr) paleointensity record is presented, using the core TOW10-9B of Lake Towuti, located in the island of Sulawesi, Indonesia, as a part of the ongoing research towards understanding the Indonesian environmental history, and reconstructing a high-resolution regional magnetic record from dating the sediments. Located in the East Sulawesi Ophiolite Belt, the bedrock surrounding Lake Towuti consists of ultramafic rocks that render the lake sediments magnetically strong, creating challenges in the reconstruction of the paleointensity record. These sediment samples were subject to a series of magnetic measurements, followed by testing the obtained paleointensity records resulting from normalizing natural remanent magnetization (NRM) against different normalizing parameters. These paleointensity records were then compared to other regional, as well as global, records of magnetic paleointensity. The results show that for the magnetically strong Lake Towuti sediments, an anhysteretic remanent magnetization (ARM) is the best normalizer. A series of magnetic paleointensity excursions are observed during the last 60 kyr, including the Laschamp excursion at 40 kyr BP, that provide new information about the magnetic history and stratigraphy of the western tropical Pacific region. We conclude that the paleointensity record of Lake Towuti is reliable and in accordance with the high-quality regional and global trends.

3.0 Tesla high spatial resolution contrast-enhanced magnetic resonance angiography (CE-MRA) of the pulmonary circulation: initial experience with a 32-channel phased array coil using a high relaxivity contrast agent.

Science.gov (United States)

Nael, Kambiz; Fenchel, Michael; Krishnam, Mayil; Finn, J Paul; Laub, Gerhard; Ruehm, Stefan G

2007-06-01

To evaluate the technical feasibility of high spatial resolution contrast-enhanced magnetic resonance angiography (CE-MRA) with highly accelerated parallel acquisition at 3.0 T using a 32-channel phased array coil, and a high relaxivity contrast agent. Ten adult healthy volunteers (5 men, 5 women, aged 21-66 years) underwent high spatial resolution CE-MRA of the pulmonary circulation. Imaging was performed at 3 T using a 32-channel phase array coil. After intravenous injection of 1 mL of gadobenate dimeglumine (Gd-BOPTA) at 1.5 mL/s, a timing bolus was used to measure the transit time from the arm vein to the main pulmonary artery. Subsequently following intravenous injection of 0.1 mmol/kg of Gd-BOPTA at the same rate, isotropic high spatial resolution data sets (1 x 1 x 1 mm3) CE-MRA of the entire pulmonary circulation were acquired using a fast gradient-recalled echo sequence (TR/TE 3/1.2 milliseconds, FA 18 degrees) and highly accelerated parallel acquisition (GRAPPA x 6) during a 20-second breath hold. The presence of artifact, noise, and image quality of the pulmonary arterial segments were evaluated independently by 2 radiologists. Phantom measurements were performed to assess the signal-to-noise ratio (SNR). Statistical analysis of data was performed by using Wilcoxon rank sum test and 2-sample Student t test. The interobserver variability was tested by kappa coefficient. All studies were of diagnostic quality as determined by both observers. The pulmonary arteries were routinely identified up to fifth-order branches, with definition in the diagnostic range and excellent interobserver agreement (kappa = 0.84, 95% confidence interval 0.77-0.90). Phantom measurements showed significantly lower SNR (P < 0.01) using GRAPPA (17.3 +/- 18.8) compared with measurements without parallel acquisition (58 +/- 49.4). The described 3 T CE-MRA protocol in addition to high T1 relaxivity of Gd-BOPTA provides sufficient SNR to support highly accelerated parallel acquisition

High angular resolution at LBT

Science.gov (United States)

Conrad, A.; Arcidiacono, C.; Bertero, M.; Boccacci, P.; Davies, A. G.; Defrere, D.; de Kleer, K.; De Pater, I.; Hinz, P.; Hofmann, K. H.; La Camera, A.; Leisenring, J.; Kürster, M.; Rathbun, J. A.; Schertl, D.; Skemer, A.; Skrutskie, M.; Spencer, J. R.; Veillet, C.; Weigelt, G.; Woodward, C. E.

2015-12-01

High angular resolution from ground-based observatories stands as a key technology for advancing planetary science. In the window between the angular resolution achievable with 8-10 meter class telescopes, and the 23-to-40 meter giants of the future, LBT provides a glimpse of what the next generation of instruments providing higher angular resolution will provide. We present first ever resolved images of an Io eruption site taken from the ground, images of Io's Loki Patera taken with Fizeau imaging at the 22.8 meter LBT [Conrad, et al., AJ, 2015]. We will also present preliminary analysis of two data sets acquired during the 2015 opposition: L-band fringes at Kurdalagon and an occultation of Loki and Pele by Europa (see figure). The light curves from this occultation will yield an order of magnitude improvement in spatial resolution along the path of ingress and egress. We will conclude by providing an overview of the overall benefit of recent and future advances in angular resolution for planetary science.

Development of high-spatial resolution TV Thomson scattering system for JFT-2M

International Nuclear Information System (INIS)

Yamauchi, Toshihiko; Shiina, Tomio; Kozawa, Teruo; Ishige, Youichi.

1996-01-01

The JFT-2M TV Thomson scattering system (TVTS) with high spatial resolution was completed in the cooperation of the fusion research and development for the DOE-JAERI collaborative program, and has been operated for 3 years. The system is composed of six subsystems; vacuum components, optics, detector, control and data acquisition, software and laser subsystems. TVTS was totally tested in the JFT-2M tokamak and the electron temperature and density profiles are measured with good reproducibility, and the increase of electron temperature by increasing toroidal magnetic field is also measured with TVTS. (author)

A method for generating high resolution satellite image time series

Science.gov (United States)

Guo, Tao

2014-10-01

There is an increasing demand for satellite remote sensing data with both high spatial and temporal resolution in many applications. But it still is a challenge to simultaneously improve spatial resolution and temporal frequency due to the technical limits of current satellite observation systems. To this end, much R&D efforts have been ongoing for years and lead to some successes roughly in two aspects, one includes super resolution, pan-sharpen etc. methods which can effectively enhance the spatial resolution and generate good visual effects, but hardly preserve spectral signatures and result in inadequate analytical value, on the other hand, time interpolation is a straight forward method to increase temporal frequency, however it increase little informative contents in fact. In this paper we presented a novel method to simulate high resolution time series data by combing low resolution time series data and a very small number of high resolution data only. Our method starts with a pair of high and low resolution data set, and then a spatial registration is done by introducing LDA model to map high and low resolution pixels correspondingly. Afterwards, temporal change information is captured through a comparison of low resolution time series data, and then projected onto the high resolution data plane and assigned to each high resolution pixel according to the predefined temporal change patterns of each type of ground objects. Finally the simulated high resolution data is generated. A preliminary experiment shows that our method can simulate a high resolution data with a reasonable accuracy. The contribution of our method is to enable timely monitoring of temporal changes through analysis of time sequence of low resolution images only, and usage of costly high resolution data can be reduces as much as possible, and it presents a highly effective way to build up an economically operational monitoring solution for agriculture, forest, land use investigation

Endoluminal ultrasound applicator with an integrated RF coil for high-resolution magnetic resonance imaging-guided high-intensity contact ultrasound thermotherapy

International Nuclear Information System (INIS)

Rata, Mihaela; Salomir, Rares; Lafon, Cyril; Umathum, Reiner; Jenne, Juergen; Bock, Michael; Cotton, Francois

2008-01-01

High-intensity contact ultrasound (HICU) under MRI guidance may provide minimally invasive treatment of endocavitary digestive tumors in the esophagus, colon or rectum. In this study, a miniature receive-only coil was integrated into an endoscopic ultrasound applicator to offer high-resolution MRI guidance of thermotherapy. A cylindrical plastic support with an incorporated single element flat transducer (9.45 MHz, water cooling tip) was made and equipped with a rectangular RF loop coil surrounding the active element. The integrated coil provided significantly higher sensitivity than a four-element extracorporeal phased array coil, and the standard deviation of the MR thermometry (SDT) improved up to a factor of 7 at 10 mm depth in tissue. High-resolution morphological images (T1w-TFE and IR-T1w-TSE with a voxel size of 0.25 x 0.25 x 3 mm 3 ) and accurate thermometry data (the PRFS method with a voxel size of 0.5 x 0.5 x 5 mm 3 , 2.2 s/image, 0.3 deg. C voxel-wise SDT) were acquired in an ex vivo esophagus sample, on a clinical 1.5T scanner. The endoscopic device was actively operated under automatic temperature control, demonstrating a high level of accuracy (1.7% standard deviation, 1.1% error of mean value), which indicates that this technology may be suitable for HICU therapy of endoluminal cancer.

Endoluminal ultrasound applicator with an integrated RF coil for high-resolution magnetic resonance imaging-guided high-intensity contact ultrasound thermotherapy

Science.gov (United States)

Rata, Mihaela; Salomir, Rares; Umathum, Reiner; Jenne, Jürgen; Lafon, Cyril; Cotton, François; Bock, Michael

2008-11-01

High-intensity contact ultrasound (HICU) under MRI guidance may provide minimally invasive treatment of endocavitary digestive tumors in the esophagus, colon or rectum. In this study, a miniature receive-only coil was integrated into an endoscopic ultrasound applicator to offer high-resolution MRI guidance of thermotherapy. A cylindrical plastic support with an incorporated single element flat transducer (9.45 MHz, water cooling tip) was made and equipped with a rectangular RF loop coil surrounding the active element. The integrated coil provided significantly higher sensitivity than a four-element extracorporeal phased array coil, and the standard deviation of the MR thermometry (SDT) improved up to a factor of 7 at 10 mm depth in tissue. High-resolution morphological images (T1w-TFE and IR-T1w-TSE with a voxel size of 0.25 × 0.25 × 3 mm3) and accurate thermometry data (the PRFS method with a voxel size of 0.5 × 0.5 × 5 mm3, 2.2 s/image, 0.3 °C voxel-wise SDT) were acquired in an ex vivo esophagus sample, on a clinical 1.5T scanner. The endoscopic device was actively operated under automatic temperature control, demonstrating a high level of accuracy (1.7% standard deviation, 1.1% error of mean value), which indicates that this technology may be suitable for HICU therapy of endoluminal cancer.

High-field superferric MR magnet

International Nuclear Information System (INIS)

Huson, F.R.; Carcagno, R.; Colvin, J.

1987-01-01

Current large-bore (>20 cm), high-field (2-T) MR magnets have major implementation disadvantages, mostly related to the extensive stray field of traditional air-core superconducting magnets. To circumvent this problem, the authors designed, constructed, and tested a 30-cm prototype superconducting, self-shielded, high field magnet. This unshimmed superferric magnet can operate between 0.5 and 4 T with a field quality of about one part per million over one quarter of its aperture. The magnet can be ramped from one field strength to another in approximately 10 minutes. The 5-Gauss line extends less than 1 meter outside the magnet structure. Further details, including MR measurements and images, are demonstrated, as well as 1-meter bore scale-up projections

Indications for application of a high resolution coil in MR tomography. Indikationen zur Applikation einer Hochaufloesungsspule in der MR-Tomographie

Energy Technology Data Exchange (ETDEWEB)

Maeurer, J. (Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany)); Requardt, H. (Siemens AG, Erlangen (Germany)); Mueller, F. (Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany)); Steinkamp, H.J. (Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany)); Hosten, N. (Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany)); Langer, R. (Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany)); Felix, R. (Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany))

1994-04-01

This is the first study with high spatial resolution Magnetic Resonance Imaging (MRI), performed with a high resolution coil in a clinical whole-body system. Measurements were recorded with a slice thickness of 2 mm. A 256x256 matrix and a 2.5 cm field of view were used resulting in a pixel size of 1.01 mm[sup 2]. MR images of the skin, hand, wrist, knee and ankle of 14 healthy volunteers, of three anatomic pathology tissue specimens and of three formalin-fixed specimens were obtained. Normal anatomy was identified and compared with the three gross anatomic pathology sections. The skin, hands, wrists and ankles of 30 patients were examined and a variety of pathological lesions were detected, including cutaneous neoplasms and ulceration, acute and chronic tendon lesions and pathologic features of the bone and wrist. Based on the excellent imaging of anatomic detail and superior contrast resolution, high resolution MRI proved an important complement for preoperative diagnosis. (orig.)

Ion optics of a high resolution multipassage mass spectrometer with electrostatic ion mirrors

Energy Technology Data Exchange (ETDEWEB)

Sakurai, T [Osaka Univ. (Japan). Dept. of Physics; Baril, M [Departement de Physique, Faculte des Sciences et de Genie, Universite Laval, Ste-Foy, Quebec G1K 7P4 (Canada)

1995-09-01

Ion trajectories in an electrostatic ion mirror are calculated. The interferences of the extended fringing fields of the mirror with finite aperture are studied. The results of the calculations are represented by three transfer matrices, which describe ion trajectories under the effects of a fringing field at the entrances, of an idealized mirror region, and of a fringing field at the exit. The focusing effects and ion-optical properties of mass spectrometers with electrostatic ion mirrors can be evaluated by using these transfer matrices. A high performance multipassage mass spectrometer is designed. The system has one magnet and four electrostatic sector analyzers and two ion mirrors. The double focusing condition and stigmatic focusing condition are achieved in any passage of the system. The mass resolution increases linearly with the number of passages in a magnet. (orig.).

High-resolution US and MR imaging of peroneal tendon injuries.

Science.gov (United States)

Taljanovic, Mihra S; Alcala, Jennifer N; Gimber, Lana H; Rieke, Joshua D; Chilvers, Margaret M; Latt, L Daniel

2015-01-01

Injuries of the peroneal tendon complex are common and should be considered in every patient who presents with chronic lateral ankle pain. These injuries occur as a result of trauma (including ankle sprains), in tendons with preexisting tendonopathy, and with repetitive microtrauma due to instability. The peroneus brevis and peroneus longus tendons are rarely torn simultaneously. Several anatomic variants, including a flat or convex fibular retromalleolar groove, hypertrophy of the peroneal tubercle at the lateral aspect of the calcaneus, an accessory peroneus quartus muscle, a low-lying peroneus brevis muscle belly, and an os peroneum, may predispose to peroneal tendon injuries. High-resolution 1.5-T and 3-T magnetic resonance (MR) imaging with use of dedicated extremity coils and high-resolution ultrasonography (US) with high-frequency linear transducers and dynamic imaging are proved to adequately depict the peroneal tendons for evaluation and can aid the orthopedic surgeon in injury management. An understanding of current treatment approaches for partial- and full-thickness peroneal tendon tears, subluxation and dislocation of these tendons with superior peroneal retinaculum (SPR) injuries, intrasheath subluxations, and peroneal tendonopathy and tenosynovitis can help physicians achieve a favorable outcome. Patients with low functional demands do well with conservative treatment, while those with high functional demands may benefit from surgery if nonsurgical treatment is unsuccessful. Radiologists should recognize the normal anatomy and specific pathologic conditions of the peroneal tendons at US and MR imaging and understand the various treatment options for peroneal tendon and SPR superior peroneal retinaculum injuries. Online supplemental material is available for this article. RSNA, 2015

High-resolution 3D Magnetic Resonance angiography in the evaluation of neck vessels and intracranial circulation

International Nuclear Information System (INIS)

Villa, A.; Di Guglielmo, L.; Campani, R.; Nicolato, A.; D'Amato, M.; Rodriguez y Balena, R.

1991-01-01

Magnetic Resonance Angiography (MRA) is a modern vascular imaging technique which allows the non-invasive and direct imaging of vessels. The authors aimed at evaluating the diagnostic accuracy of MRA in the study of pathologic conditions in the neck and intracranial vessels; spatial resolution of the technique was also investigated. Twenty-four healthy volunteers and 82 patients suffering from various diseases of the head and neck vessels were included in the study. First of all, MRA capabilities ware investigated in visualizing normal vessels of both neck and intracranial circle. The diagnostic accuracy of the method was then evaluated in the study of vascular diseases, and the results compared with conventional/digital angiographic findings. The comparison demonstrated how stenoses and atherosclerotic plaques tend to be overestimated by MRA because of technical artifacts inherent to the technique itself, whereas vascular ulcerations and aneurysms are frequently underestimated. However, this data was steady and therefore evaluable- the exact knowledge of the artifacts making diagnosis reliable. The diagnostic and technical problems relative to the various vascular diseases are discussed. Finally, several hypotheses of diagnostic iter are suggested

Resolution Improvements in in Vivo1H NMR Spectra with Increased Magnetic Field Strength

Science.gov (United States)

Gruetter, Rolf; Weisdorf, Sally A.; Rajanayagan, Vasantham; Terpstra, Melissa; Merkle, Hellmut; Truwit, Charles L.; Garwood, Michael; Nyberg, Scott L.; Ugurbil, Kâmil

1998-11-01

The measurement of cerebral metabolites using highly homologous localization techniques and similar shimming methods was performed in the human brain at 1.5 and 4 T as well as in the dog and rat brain at 9.4 T. In rat brain, improved resolution was achieved by shimming all first- and second-order shim coils using a fully adiabatic FASTMAP sequence. The spectra showed a clear improvement in spectral resolution for all metabolite resonances with increased field strength. Changes in cerebral glutamine content were clearly observed at 4 T compared to 1.5 T in patients with hepatic encephalopathy. At 9.4 T, glutamine H4 at 2.46 ppm was fully resolved from glutamate H4 at 2.37 ppm, as was the potential resonance from γ-amino-butyric acid at 2.30 ppm and N-acetyl-aspartyl-glutamate at 2.05 ppm. Singlet linewidths were found to be as low as 6 Hz (0.015 ppm) at 9.4 T, indicating a substantial decrease in ppm linewidth with field strength. Furthermore, the methylene peak of creatine was partially resolved from phosphocreatine, indicating a close to 1:1 relationship in gray matter. We conclude that increasing the magnetic field strength increases spectral resolution also for1H NMR, which can lead to more than linear sensitivity gains.

High-resolution vector magnetometry: Piezo-spin-polarization effect and in-plane strain-induced dominating uniaxial magnetic anisotropy in a 200-nm-thick Ni thin film

Science.gov (United States)

Benito, L.

2018-04-01

Owing to its high-sensitivity, reliability, fast, versatile and cost-effective operation, vibrating sample magnetometers (VSM) are massively popular characterization instruments at Magnetism laboratories worldwide. Nevertheless, the inherent appearance of synchronous noise represents a major drawback, which critically limits the fine probing of nanometer-sized media. I here report on an innovative approach to eliminate synchronous noise in VSM. This consists of fitting engineered mechanical devices that absorbs vibration energy, dissipating that into heat. Complementarily, a novel transversal pick-up coil system is also presented and analyzed; this detection system has been engineered to enhance the noise-to-signal ratio and optimized for measuring small size thin film samples. The implementation of a combined mechanical and electromagnetic approach enables to notably enhance the VSM performance, achieving a sensitivity better than 1 ×10-6 emu and a resolution below 5 ×10-8 emu, so that the magnetization vector in nanostructured media can be accurately mapped out down to cryogenic temperatures. I lastly show precision magnetometry measurements carried out in an epitaxial (0 0 1)-oriented 200 nm-thick Ni thin film. The analysis reveals the arising of an in-plane dominating strain-induced uniaxial magnetic anisotropy, K2ef = - 6.455kJ m - 3 , and a stunning piezo-spin-polarization effect resulting in a remarkable 10% modulation of the magnetization vector, ∼ 27 emu/cm3, with respect to the cubic lattice axes. Both effects are attributed to the likely existence of an orthorhombic lattice distortion, i.e.εxx -εyy ≈ - 2 ×10-3 . This categorical link enables to assign the observed anisotropic spin-polarization in the Ni overlayer to a two-ion magnetoelastic coupling effect.

Resolution enhancement of low-quality videos using a high-resolution frame

Science.gov (United States)

Pham, Tuan Q.; van Vliet, Lucas J.; Schutte, Klamer

2006-01-01

This paper proposes an example-based Super-Resolution (SR) algorithm of compressed videos in the Discrete Cosine Transform (DCT) domain. Input to the system is a Low-Resolution (LR) compressed video together with a High-Resolution (HR) still image of similar content. Using a training set of corresponding LR-HR pairs of image patches from the HR still image, high-frequency details are transferred from the HR source to the LR video. The DCT-domain algorithm is much faster than example-based SR in spatial domain 6 because of a reduction in search dimensionality, which is a direct result of the compact and uncorrelated DCT representation. Fast searching techniques like tree-structure vector quantization 16 and coherence search1 are also key to the improved efficiency. Preliminary results on MJPEG sequence show promising result of the DCT-domain SR synthesis approach.

A cloud mask methodology for high resolution remote sensing data combining information from high and medium resolution optical sensors

Science.gov (United States)

Sedano, Fernando; Kempeneers, Pieter; Strobl, Peter; Kucera, Jan; Vogt, Peter; Seebach, Lucia; San-Miguel-Ayanz, Jesús

2011-09-01

This study presents a novel cloud masking approach for high resolution remote sensing images in the context of land cover mapping. As an advantage to traditional methods, the approach does not rely on thermal bands and it is applicable to images from most high resolution earth observation remote sensing sensors. The methodology couples pixel-based seed identification and object-based region growing. The seed identification stage relies on pixel value comparison between high resolution images and cloud free composites at lower spatial resolution from almost simultaneously acquired dates. The methodology was tested taking SPOT4-HRVIR, SPOT5-HRG and IRS-LISS III as high resolution images and cloud free MODIS composites as reference images. The selected scenes included a wide range of cloud types and surface features. The resulting cloud masks were evaluated through visual comparison. They were also compared with ad-hoc independently generated cloud masks and with the automatic cloud cover assessment algorithm (ACCA). In general the results showed an agreement in detected clouds higher than 95% for clouds larger than 50 ha. The approach produced consistent results identifying and mapping clouds of different type and size over various land surfaces including natural vegetation, agriculture land, built-up areas, water bodies and snow.

Levitation force and magnetization in bulk and thin film high Tc superconductors

International Nuclear Information System (INIS)

Riise, A.B

1998-04-01

The authors present high-resolution measurements of the repulsive vertical force and its associated stiffness between a Nd-B-Fe magnet and a YBa 2 Cu 3 O 7-δ superconductor in cylindrical geometry. The results are compared with theoretical predictions. The calculations are based on a model in which the superconductor is assumed to be either a sintered granular material or consisting of grains embedded in a nonactive matrix so that only intragranular currents are important. The critical state model is applied to each grain individually and closed form expressions for both vertical force F z and stiffness are obtained in a configuration with cylindrical symmetry. The model explains all features of the experimental results in a consistent way. A good quantitative agreement has been obtained using only three adjustable parameters. Several central aspects of the phenomenon of magnetic levitation with high-T c superconductors are presented. High-resolution measurements are made of the repulsive vertical force and its associated stiffness as well as the horizontal stabilizing force and the stiffness governing lateral vibrations. The results obtained at 77 K using a granular YBa 2 Cu 3 O 7-δ sample and Nd-Fe-B magnet in a rectangular levitation configuration are compared with theoretical predictions. The calculations, which are based on the critical state model with the assumption that it applies to the grins individually, give closed-form expressions for all the measured quantities. It is concluded that the present model explains all features of the observations in a consistent way. Using only three adjustable parameters a good agreement exists also at a quantitative level. Experimental studies and theoretical modelling of the levitation force on a permanent magnet placed above a superconducting thin film are offered. It is shown that measurements of the levitation force is a simple and precise method to determine the critical current density in thin films

High-Resolution Mass Spectrometers

Science.gov (United States)

Marshall, Alan G.; Hendrickson, Christopher L.

2008-07-01

Over the past decade, mass spectrometry has been revolutionized by access to instruments of increasingly high mass-resolving power. For small molecules up to ˜400 Da (e.g., drugs, metabolites, and various natural organic mixtures ranging from foods to petroleum), it is possible to determine elemental compositions (CcHhNnOoSsPp…) of thousands of chemical components simultaneously from accurate mass measurements (the same can be done up to 1000 Da if additional information is included). At higher mass, it becomes possible to identify proteins (including posttranslational modifications) from proteolytic peptides, as well as lipids, glycoconjugates, and other biological components. At even higher mass (˜100,000 Da or higher), it is possible to characterize posttranslational modifications of intact proteins and to map the binding surfaces of large biomolecule complexes. Here we review the principles and techniques of the highest-resolution analytical mass spectrometers (time-of-flight and Fourier transform ion cyclotron resonance and orbitrap mass analyzers) and describe some representative high-resolution applications.

USGS High Resolution Orthoimagery Collection - Historical - National Geospatial Data Asset (NGDA) High Resolution Orthoimagery

Data.gov (United States)

U.S. Geological Survey, Department of the Interior — USGS high resolution orthorectified images from The National Map combine the image characteristics of an aerial photograph with the geometric qualities of a map. An...

High throughput screening of ligand binding to macromolecules using high resolution powder diffraction

Science.gov (United States)

Von Dreele, Robert B.; D'Amico, Kevin

2006-10-31

A process is provided for the high throughput screening of binding of ligands to macromolecules using high resolution powder diffraction data including producing a first sample slurry of a selected polycrystalline macromolecule material and a solvent, producing a second sample slurry of a selected polycrystalline macromolecule material, one or more ligands and the solvent, obtaining a high resolution powder diffraction pattern on each of said first sample slurry and the second sample slurry, and, comparing the high resolution powder diffraction pattern of the first sample slurry and the high resolution powder diffraction pattern of the second sample slurry whereby a difference in the high resolution powder diffraction patterns of the first sample slurry and the second sample slurry provides a positive indication for the formation of a complex between the selected polycrystalline macromolecule material and at least one of the one or more ligands.

In-situ high-resolution gamma-spectrometric survey of burial ground-monitoring wells

International Nuclear Information System (INIS)

Bowman, W.W.

1981-09-01

In situ high resolution gamma-ray spectrometry with an intrinsic germanium detector assembly of special design surveyed the burial ground monitoring wells to locate and identify gamma emitters that may have migrated from the burial trenches toward the water table. Gamma-ray spectra were acquired as a function of depth in each well and recorded on magnetic tape. These spectra were reduced by a series of computer programs to produce count rate versus depth profiles for natural and man-made activities. The original spectra and the profiles have been archived on magnetic tape for comparison with similar future surveys. Large amounts of man-made activities were observed in some of the burial trenches; however, below the trench bottoms, only very low but detectable amounts of 60 Co and 137 Cs were observed in eleven wells. The highest level of man-made gamma activity observed below the trench bottoms has a count rate roughly equal to that observed for uranium daughter activities which are natural to the subsoil

Rectal cancer staging: focus on the prognostic significance of the findings described by high-resolution magnetic resonance imaging

Science.gov (United States)

2013-01-01

Abstract High-resolution (HR) magnetic resonance imaging (MRI) has become an indispensable tool for multidisciplinary teams (MDTs) addressing rectal cancer. It provides anatomic information for surgical planning and allows patients to be stratified into different groups according to the risk of local and distant recurrence. One of the objectives of the MDT is the preoperative identification of high-risk patients who will benefit from neoadjuvant treatment. For this reason, the correct evaluation of the circumferential resection margin (CRM), the depth of tumor spread beyond the muscularis propria, extramural vascular invasion and nodal status is of the utmost importance. Low rectal tumors represent a special challenge for the MDT, because decisions seek a balance between oncologic safety, in the pursuit of free resection margins, and the patient’s quality of life, in order to preserve sphincter function. At present, the exchange of information between the different specialties involved in dealing with patients with rectal cancer can rank the contribution of colleagues, auditing their work and incorporating knowledge that will lead to a better understanding of the pathology. Thus, beyond the anatomic description of the images, the radiologist’s role in the MDT makes it necessary to know the prognostic value of the findings that we describe, in terms of recurrence and survival, because these findings affect decision making and, therefore, the patients’ life. In this review, the usefulness of HR MRI in the initial staging of rectal cancer and in the evaluation of neoadjuvant treatment, with a focus on the prognostic value of the findings, is described as well as the contribution of HR MRI in assessing patients with suspected or confirmed recurrence of rectal cancer. PMID:23876415

Rectal cancer staging: focus on the prognostic significance of the findings described by high-resolution magnetic resonance imaging.

Science.gov (United States)

Dieguez, Adriana

2013-07-22

High-resolution (HR) magnetic resonance imaging (MRI) has become an indispensable tool for multidisciplinary teams (MDTs) addressing rectal cancer. It provides anatomic information for surgical planning and allows patients to be stratified into different groups according to the risk of local and distant recurrence. One of the objectives of the MDT is the preoperative identification of high-risk patients who will benefit from neoadjuvant treatment. For this reason, the correct evaluation of the circumferential resection margin (CRM), the depth of tumor spread beyond the muscularis propria, extramural vascular invasion and nodal status is of the utmost importance. Low rectal tumors represent a special challenge for the MDT, because decisions seek a balance between oncologic safety, in the pursuit of free resection margins, and the patient's quality of life, in order to preserve sphincter function. At present, the exchange of information between the different specialties involved in dealing with patients with rectal cancer can rank the contribution of colleagues, auditing their work and incorporating knowledge that will lead to a better understanding of the pathology. Thus, beyond the anatomic description of the images, the radiologist's role in the MDT makes it necessary to know the prognostic value of the findings that we describe, in terms of recurrence and survival, because these findings affect decision making and, therefore, the patients' life. In this review, the usefulness of HR MRI in the initial staging of rectal cancer and in the evaluation of neoadjuvant treatment, with a focus on the prognostic value of the findings, is described as well as the contribution of HR MRI in assessing patients with suspected or confirmed recurrence of rectal cancer.

Visualization of intracranial vessel anatomy using high resolution MRI and a simple image fusion technique

International Nuclear Information System (INIS)

Nasel, C.

2005-01-01

A new technique for fusion and 3D viewing of high resolution magnetic resonance (MR) angiography and morphological MR sequences is reported. Scanning and image fusion was possible within 20 min on a standard 1.5 T MR-scanner. The procedure was successfully performed in 10 consecutive cases with excellent visualization of wall and luminal aspects of the intracranial segments of the internal carotid artery, the vertebrobasilar system and the anterior, middle and posterior cerebral artery

Visualization of intracranial vessel anatomy using high resolution MRI and a simple image fusion technique

Energy Technology Data Exchange (ETDEWEB)

Nasel, C. [Division of Neuroradiology, Department of Radiology, Medical University of Vienna, Waehringerguertel 18-20, A-1090 Vienna (Austria)]. E-mail: christian.nasel@perfusion.at

2005-04-01

A new technique for fusion and 3D viewing of high resolution magnetic resonance (MR) angiography and morphological MR sequences is reported. Scanning and image fusion was possible within 20 min on a standard 1.5 T MR-scanner. The procedure was successfully performed in 10 consecutive cases with excellent visualization of wall and luminal aspects of the intracranial segments of the internal carotid artery, the vertebrobasilar system and the anterior, middle and posterior cerebral artery.

Resolution improvement of low frequency AC magnetic field detection for modulated MR sensors.

Science.gov (United States)

Hu, Jinghua; Pan, Mengchun; Hu, Jiafei; Li, Sizhong; Chen, Dixiang; Tian, Wugang; Sun, Kun; Du, Qingfa; Wang, Yuan; Pan, Long; Zhou, Weihong; Zhang, Qi; Li, Peisen; Peng, Junping; Qiu, Weicheng; Zhou, Jikun

2017-09-01

Magnetic modulation methods especially Micro-Electro-Mechanical System (MEMS) modulation can improve the sensitivity of magnetoresistive (MR) sensors dramatically, and pT level detection of Direct Current (DC) magnetic field can be realized. While in a Low Frequency Alternate Current (LFAC) magnetic field measurement situation, frequency measurement is limited by a serious spectrum aliasing problem caused by the remanence in sensors and geomagnetic field, leading to target information loss because frequency indicates the magnetic target characteristics. In this paper, a compensation field produced with integrated coils is applied to the MR sensor to remove DC magnetic field distortion, and a LFAC magnetic field frequency estimation algorithm is proposed based on a search of the database, which is derived from the numerical model revealing the relationship of the LFAC frequency and determination factor [defined by the ratio of Discrete Fourier Transform (DFT) coefficients]. In this algorithm, an inverse modulation of sensor signals is performed to detect jumping-off point of LFAC in the time domain; this step is exploited to determine sampling points to be processed. A determination factor is calculated and taken into database to figure out frequency with a binary search algorithm. Experimental results demonstrate that the frequency measurement resolution of the LFAC magnetic field is improved from 12.2 Hz to 0.8 Hz by the presented method, which, within the signal band of a magnetic anomaly (0.04-2 Hz), indicates that the proposed method may expand the applications of magnetoresistive (MR) sensors to human healthcare and magnetic anomaly detection (MAD).

Magnetic structure and microstructure of die-upset hard magnets RE13.75Fe80.25B6 (RE=Nd, Pr): A possible origin of high coercivity

International Nuclear Information System (INIS)

Volkov, V.V.; Zhu, Y.

1999-01-01

In situ transmission electron microscopy magnetizing experiments combined with Lorentz magnetic microscopy in Fresnel endash Foucault modes were used to characterize the magnetic structure of die-upset, high energy-product hard magnets Nd 13.75 Fe 80.25 B 6 and Pr 13.75 Fe 80.25 B 6 . Experimental observations indicate a well-aligned grain structure and quasiperiodic nonaligned open-quotes extended defectclose quotes layers transverse to press direction. The local remanence of the open-quotes defectclose quotes layers is far from saturation when the external field is removed. The layers are enriched with inclusions of approximate composition Nd 7 Fe 3 , generally with a polygonal shape, and are associated with the original ribbon interfaces. They may be responsible for a high coercivity mechanism, since the motion of reverse domains can be impeded by these layers, even when they are nucleated. Thus, a delayed nucleation of reversed domains seems to be a limiting factor for magnetization reversal and coercivity force. Both Lorentz magnetic imaging and high-resolution microscopy highlight the role of magnetocrystalline anisotropy for domain wall-grain boundary interactions and pinning. Local remanence was estimated directly from magnetic moment sensitive Foucault images. copyright 1999 American Institute of Physics

Texton-based super-resolution for achieving high spatiotemporal resolution in hybrid camera system

Science.gov (United States)

Kamimura, Kenji; Tsumura, Norimichi; Nakaguchi, Toshiya; Miyake, Yoichi

2010-05-01

Many super-resolution methods have been proposed to enhance the spatial resolution of images by using iteration and multiple input images. In a previous paper, we proposed the example-based super-resolution method to enhance an image through pixel-based texton substitution to reduce the computational cost. In this method, however, we only considered the enhancement of a texture image. In this study, we modified this texton substitution method for a hybrid camera to reduce the required bandwidth of a high-resolution video camera. We applied our algorithm to pairs of high- and low-spatiotemporal-resolution videos, which were synthesized to simulate a hybrid camera. The result showed that the fine detail of the low-resolution video can be reproduced compared with bicubic interpolation and the required bandwidth could be reduced to about 1/5 in a video camera. It was also shown that the peak signal-to-noise ratios (PSNRs) of the images improved by about 6 dB in a trained frame and by 1.0-1.5 dB in a test frame, as determined by comparison with the processed image using bicubic interpolation, and the average PSNRs were higher than those obtained by the well-known Freeman’s patch-based super-resolution method. Compared with that of the Freeman’s patch-based super-resolution method, the computational time of our method was reduced to almost 1/10.

High-resolution proton and carbon-13 NMR of membranes: why sonicate?

International Nuclear Information System (INIS)

Oldfield, E.; Bowers, J.L.; Forbes, J.

1987-01-01

The authors have obtained high-field (11.7-T) proton and carbon-13 Fourier transform (FT) nuclear magnetic resonance (NMR) spectra of egg lecithin and egg lecithin-chloresterol (1:1) multibilayers, using magic-angle sample spinning (MASS) techniques, and sonicated egg lecithin and egg lecithin-cholesterol (1:1) vesicles, using conventional FT NMR methods. Resolution of the proton and carbon-13 MASS NMR spectra of the pure egg lecithin samples is essentially identical with that of sonicated samples, but spectra of the unsonicated lipid, using MASS, can be obtained very much faster than with the more dilute, sonicated systems. With the 1:1 lecithin-cholesterol system, proton MASS NMR spectra are virtually identical with conventional FT spectra of sonicated samples, while the 13 C NMR, the authors demonstrate that most 13 C nuclei in the cholesterol moiety can be monitored, even though these same nuclei are essentially invisible, i.e., are severely broadened, in the corresponding sonicated systems. In addition, 13 C MASS NMR spectra can again be recorded much faster than with sonicated samples, due to concentration effects. Taken together, these results strongly suggest there will seldom be need in the future to resort to ultransonic disruption of lipid bilayer membranes in order to obtain high-resolution proton or carbon-13 NMR spectra

High temporal resolution magnetic resonance imaging: development of a parallel three dimensional acquisition method for functional neuroimaging

International Nuclear Information System (INIS)

Rabrait, C.

2007-11-01

Echo Planar Imaging is widely used to perform data acquisition in functional neuroimaging. This sequence allows the acquisition of a set of about 30 slices, covering the whole brain, at a spatial resolution ranging from 2 to 4 mm, and a temporal resolution ranging from 1 to 2 s. It is thus well adapted to the mapping of activated brain areas but does not allow precise study of the brain dynamics. Moreover, temporal interpolation is needed in order to correct for inter-slices delays and 2-dimensional acquisition is subject to vascular in flow artifacts. To improve the estimation of the hemodynamic response functions associated with activation, this thesis aimed at developing a 3-dimensional high temporal resolution acquisition method. To do so, Echo Volume Imaging was combined with reduced field-of-view acquisition and parallel imaging. Indeed, E.V.I. allows the acquisition of a whole volume in Fourier space following a single excitation, but it requires very long echo trains. Parallel imaging and field-of-view reduction are used to reduce the echo train durations by a factor of 4, which allows the acquisition of a 3-dimensional brain volume with limited susceptibility-induced distortions and signal losses, in 200 ms. All imaging parameters have been optimized in order to reduce echo train durations and to maximize S.N.R., so that cerebral activation can be detected with a high level of confidence. Robust detection of brain activation was demonstrated with both visual and auditory paradigms. High temporal resolution hemodynamic response functions could be estimated through selective averaging of the response to the different trials of the stimulation. To further improve S.N.R., the matrix inversions required in parallel reconstruction were regularized, and the impact of the level of regularization on activation detection was investigated. Eventually, potential applications of parallel E.V.I. such as the study of non-stationary effects in the B.O.L.D. response

High-resolution nuclear magnetic resonance of quadrupolar nuclei in solids

International Nuclear Information System (INIS)

Charpentier, Th.

1998-01-01

After a brief review of existing methods in high-resolution NMR of quadrupolar nuclei, the manipulation of multi-quantum coherencies by radiofrequency pulses is studied. Results are then applied to the determination of optimal conditions for performing the recently introduced multiple-quantum magic-angle experiment (MQMAS). The principles of this new method, the different pulse sequences and the data processing are described in detail. Applications on aluminum hydrates and cement pastes show the improvements of this new technique over the previous ones. In a second part, after an investigation of the Floquet theory, a new formalism has been devised for studying the behavior of a spin submitted to a strong quadrupolar interaction and radiofrequency field in a rotating sample. This formalism is then applied to a quantitative study of the phenomenon of rotational induced adiabatic transfer of coherencies (RIACT). The extension of our theoretical approach to two-dimensional experiments provides a powerful tool for quantitative analyses of MQMAS spectra. Agreement between experimental data and simulations demonstrates the reliability of our approach. Preliminary results concerning the application of MQMAS spectroscopy, using our simulation programs, to structural study of amorphous materials are presented. The third and last part presents a theoretical and experimental investigation of dipolar order in a rotating sample. Two theoretical models are described, the first for the slow spinning speed regime where an adiabatic approximation can be made, and the second for the fast spinning speed regime. (author)

Immersion Gratings for Infrared High-resolution Spectroscopy

Science.gov (United States)

Sarugaku, Yuki; Ikeda, Yuji; Kobayashi, Naoto; Kaji, Sayumi; Sukegawa, Takashi; Sugiyama, Shigeru; Nakagawa, Takao; Arasaki, Takayuki; Kondo, Sohei; Nakanishi, Kenshi; Yasui, Chikako; Kawakita, Hideyo

2016-10-01

High-resolution spectroscopy in the infrared wavelength range is essential for observations of minor isotopologues, such as HDO for water, and prebiotic organic molecules like hydrocarbons/P-bearing molecules because numerous vibrational molecular bands (including non-polar molecules) are located in this wavelength range. High spectral resolution enables us to detect weak lines without spectral line confusion. This technique has been widely used in planetary sciences, e.g., cometary coma (H2O, CO, and organic molecules), the martian atmosphere (CH4, CO2, H2O and HDO), and the upper atmosphere of gas giants (H3+ and organic molecules such as C2H6). Spectrographs with higher resolution (and higher sensitivity) still have a potential to provide a plenty of findings. However, because the size of spectrographs scales with the spectral resolution, it is difficult to realize it.Immersion grating (IG), which is a diffraction grating wherein the diffraction surface is immersed in a material with a high refractive index (n > 2), provides n times higher spectral resolution compared to a reflective grating of the same size. Because IG reduces the size of spectrograph to 1/n compared to the spectrograph with the same spectral resolution using a conventional reflective grating, it is widely acknowledged as a key optical device to realize compact spectrographs with high spectral resolution.Recently, we succeeded in fabricating a CdZnTe immersion grating with the theoretically predicted diffraction efficiency by machining process using an ultrahigh-precision five-axis processing machine developed by Canon Inc. Using the same technique, we completed a practical germanium (Ge) immersion grating with both a reflection coating on the grating surface and the an AR coating on the entrance surface. It is noteworthy that the wide wavelength range from 2 to 20 um can be covered by the two immersion gratings.In this paper, we present the performances and the applications of the immersion

Incremental Value of Plaque Enhancement in Patients with Moderate or Severe Basilar Artery Stenosis: 3.0 T High-Resolution Magnetic Resonance Study.

Science.gov (United States)

Wang, Wanqian; Yang, Qi; Li, Debiao; Fan, Zhaoyang; Bi, Xiaoming; Du, Xiangying; Wu, Fang; Wu, Ye; Li, Kuncheng

2017-01-01

To investigate the clinical relevance of plaque's morphological characteristics and distribution pattern using 3.0 T high-resolution magnetic resonance imaging (HRMRI) in patients with moderate or severe basilar artery (BA) atherosclerosis stenosis. Fifty-seven patients (33 symptomatic patients and 24 asymptomatic patients) were recruited for 3.0 T HRMRI scan; all of them had >50% stenosis on the BA. The intraplaque hemorrhage (IPH), contrast-enhancement pattern, and distribution of BA plaques were compared between the symptomatic and asymptomatic groups. Factors potentially associated with posterior ischemic stroke were calculated by multivariate analyses. Enhancement of BA plaque was more frequently observed in symptomatic than in asymptomatic patients (27/33, 81.8% versus 11/24, 45.8%; p 50%. Plaques were mainly distributed at the ventral site (39.3%) or involved more than two arcs (21.2%) in the symptomatic group but were mainly distributed at left (33.3%) and right (25.0%) sites in the asymptomatic group.

High resolution tomographic instrument development

International Nuclear Information System (INIS)

1992-01-01

Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational

High resolution tomographic instrument development

Energy Technology Data Exchange (ETDEWEB)

1992-08-01

Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

High resolution tomographic instrument development

Energy Technology Data Exchange (ETDEWEB)

1992-01-01

Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

X-ray magnetic circular dichroism used to image magnetic domains

CERN Document Server

Fischer, P; Kalchgruber, R; Schütz, G M; Schmahl, G; Guttmann, P; Bayreuther, G

1999-01-01

A new technique to image magnetic domain structures has been established by the combination of the high resolution transmission X- ray microscope (TXM) at BESSY I based on the zone plate technique with the X-ray magnetic circular $9 dichroism (X-MCD) providing a huge magnetic contrast. A lateral spatial resolution down to 30 nm could be achieved. Basic features of X-MCD are the inherent element- specificity and the potential to gain information on the local spin $9 and orbital moments of the absorbing species applying magneto-optical sum rules. Key results at the Fe L/sub 3,2/ edges of Fe in a layered GdFe system and at the Co L/sub 3/ edge of a PtCo layered system demonstrate the potential of $9 this microscopy. The images can be recorded in varying magnetic fields which allows to study the evolution of magnetic domains within a complete hysteresis loop. (8 refs).

Fourier Transfrom Ion Cyclotron Resonance Mass Spectrometry at High Magnetic Field

Science.gov (United States)

Marshall, Alan G.

1998-03-01

At high magnetic field (9.4 tesla at NHMFL), Fourier transform ion cyclotron resonance mass spectrometry performance improves dramatically: mass resolving power, axialization efficiency, and scan speed (each proportional to B), maximum ion mass, dynamic range, ion trapping period, kinetic energy, and electron self-cooling rate for sympathetic cooling (each proportional to B^2), and ion coalescence tendency (proportional 1/B^2). These advantages may apply singly (e.g., unit mass resolution for proteins of >100,000 Da), or compound (e.g., 10-fold improvement in S/N ratio for 9.4 T vs. 6 T at the same resolving power). Examples range from direct determination of molecular formulas of diesel fuel components by accurate mass measurement (=B10.1 ppm) to protein structure and dynamics probed by H/D exchange. This work was supported by N.S.F. (CHE-93-22824; CHE-94-13008), N.I.H. (GM-31683), Florida State University, and the National High Magnetic Field Laboratory in Tallahassee, FL.

4.5 Tesla magnetic field reduces range of high-energy positrons -- Potential implications for positron emission tomography

International Nuclear Information System (INIS)

Wirrwar, A.; Vosberg, H.; Herzog, H.; Halling, H.; Weber, S.; Mueller-Gaertner, H.W.; Forschungszentrum Juelich GmbH

1997-01-01

The authors have theoretically and experimentally investigated the extent to which homogeneous magnetic fields up to 7 Tesla reduce the spatial distance positrons travel before annihilation (positron range). Computer simulations of a noncoincident detector design using a Monte Carlo algorithm calculated the positron range as a function of positron energy and magnetic field strength. The simulation predicted improvements in resolution, defined as full-width at half-maximum (FWHM) of the line-spread function (LSF) for a magnetic field strength up to 7 Tesla: negligible for F-18, from 3.35 mm to 2.73 mm for Ga-68 and from 3.66 mm to 2.68 mm for Rb-82. Also a substantial noise suppression was observed, described by the full-width at tenth-maximum (FWTM) for higher positron energies. The experimental approach confirmed an improvement in resolution for Ga-68 from 3.54 mm at 0 Tesla to 2.99 mm FWHM at 4.5 Tesla and practically no improvement for F-18 (2.97 mm at 0 Tesla and 2.95 mm at 4.5 Tesla). It is concluded that the simulation model is appropriate and that a homogeneous static magnetic field of 4.5 Tesla reduces the range of high-energy positrons to an extent that may improve spatial resolution in positron emission tomography

High Resolution Global Electrical Conductivity Variations in the Earth's Mantle

Science.gov (United States)

Kelbert, A.; Sun, J.; Egbert, G. D.

2013-12-01

Electrical conductivity of the Earth's mantle is a valuable constraint on the water content and melting processes. In Kelbert et al. (2009), we obtained the first global inverse model of electrical conductivity in the mantle capable of providing constraints on the lateral variations in mantle water content. However, in doing so we had to compromise on the problem complexity by using the historically very primitive ionospheric and magnetospheric source assumptions. In particular, possible model contamination by the auroral current systems had greatly restricted our use of available data. We have now addressed this problem by inverting for the external sources along with the electrical conductivity variations. In this study, we still focus primarily on long period data that are dominated by quasi-zonal source fields. The improved understanding of the ionospheric sources allows us to invert the magnetic fields directly, without a correction for the source and/or the use of transfer functions. It allows us to extend the period range of available data to 1.2 days - 102 days, achieving better sensitivity to the upper mantle and transition zone structures. Finally, once the source effects in the data are accounted for, a much larger subset of observatories may be used in the electrical conductivity inversion. Here, we use full magnetic fields at 207 geomagnetic observatories, which include mid-latitude, equatorial and high latitude data. Observatory hourly means from the years 1958-2010 are employed. The improved quality and spatial distribution of the data set, as well as the high resolution modeling and inversion using degree and order 40 spherical harmonics mapped to a 2x2 degree lateral grid, all contribute to the much improved resolution of our models, representing a conceptual step forward in global electromagnetic sounding. We present a fully three-dimensional, global electrical conductivity model of the Earth's mantle as inferred from ground geomagnetic

High spatial resolution brain functional MRI using submillimeter balanced steady-state free precession acquisition

International Nuclear Information System (INIS)

Wu, Pei-Hsin; Chung, Hsiao-Wen; Tsai, Ping-Huei; Wu, Ming-Long; Chuang, Tzu-Chao; Shih, Yi-Yu; Huang, Teng-Yi

2013-01-01

Purpose: One of the technical advantages of functional magnetic resonance imaging (fMRI) is its precise localization of changes from neuronal activities. While current practice of fMRI acquisition at voxel size around 3 × 3 × 3 mm 3 achieves satisfactory results in studies of basic brain functions, higher spatial resolution is required in order to resolve finer cortical structures. This study investigated spatial resolution effects on brain fMRI experiments using balanced steady-state free precession (bSSFP) imaging with 0.37 mm 3 voxel volume at 3.0 T. Methods: In fMRI experiments, full and unilateral visual field 5 Hz flashing checkerboard stimulations were given to healthy subjects. The bSSFP imaging experiments were performed at three different frequency offsets to widen the coverage, with functional activations in the primary visual cortex analyzed using the general linear model. Variations of the spatial resolution were achieved by removing outerk-space data components. Results: Results show that a reduction in voxel volume from 3.44 × 3.44 × 2 mm 3 to 0.43 × 0.43 × 2 mm 3 has resulted in an increase of the functional activation signals from (7.7 ± 1.7)% to (20.9 ± 2.0)% at 3.0 T, despite of the threefold SNR decreases in the original images, leading to nearly invariant functional contrast-to-noise ratios (fCNR) even at high spatial resolution. Activation signals aligning nicely with gray matter sulci at high spatial resolution would, on the other hand, have possibly been mistaken as noise at low spatial resolution. Conclusions: It is concluded that the bSSFP sequence is a plausible technique for fMRI investigations at submillimeter voxel widths without compromising fCNR. The reduction of partial volume averaging with nonactivated brain tissues to retain fCNR is uniquely suitable for high spatial resolution applications such as the resolving of columnar organization in the brain

High spatial resolution brain functional MRI using submillimeter balanced steady-state free precession acquisition

Energy Technology Data Exchange (ETDEWEB)

Wu, Pei-Hsin; Chung, Hsiao-Wen [Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Tsai, Ping-Huei [Imaging Research Center, Taipei Medical University, Taipei 11031, Taiwan and Department of Medical Imaging, Taipei Medical University Hospital, Taipei Medical University, Taipei 11031, Taiwan (China); Wu, Ming-Long, E-mail: minglong.wu@csie.ncku.edu.tw [Institute of Medical Informatics, National Cheng-Kung University, Tainan 70101, Taiwan and Department of Computer Science and Information Engineering, National Cheng-Kung University, Tainan 70101, Taiwan (China); Chuang, Tzu-Chao [Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan (China); Shih, Yi-Yu [Siemens Limited Healthcare Sector, Taipei 11503, Taiwan (China); Huang, Teng-Yi [Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China)

2013-12-15

Purpose: One of the technical advantages of functional magnetic resonance imaging (fMRI) is its precise localization of changes from neuronal activities. While current practice of fMRI acquisition at voxel size around 3 × 3 × 3 mm{sup 3} achieves satisfactory results in studies of basic brain functions, higher spatial resolution is required in order to resolve finer cortical structures. This study investigated spatial resolution effects on brain fMRI experiments using balanced steady-state free precession (bSSFP) imaging with 0.37 mm{sup 3} voxel volume at 3.0 T. Methods: In fMRI experiments, full and unilateral visual field 5 Hz flashing checkerboard stimulations were given to healthy subjects. The bSSFP imaging experiments were performed at three different frequency offsets to widen the coverage, with functional activations in the primary visual cortex analyzed using the general linear model. Variations of the spatial resolution were achieved by removing outerk-space data components. Results: Results show that a reduction in voxel volume from 3.44 × 3.44 × 2 mm{sup 3} to 0.43 × 0.43 × 2 mm{sup 3} has resulted in an increase of the functional activation signals from (7.7 ± 1.7)% to (20.9 ± 2.0)% at 3.0 T, despite of the threefold SNR decreases in the original images, leading to nearly invariant functional contrast-to-noise ratios (fCNR) even at high spatial resolution. Activation signals aligning nicely with gray matter sulci at high spatial resolution would, on the other hand, have possibly been mistaken as noise at low spatial resolution. Conclusions: It is concluded that the bSSFP sequence is a plausible technique for fMRI investigations at submillimeter voxel widths without compromising fCNR. The reduction of partial volume averaging with nonactivated brain tissues to retain fCNR is uniquely suitable for high spatial resolution applications such as the resolving of columnar organization in the brain.

A high-resolution EPR-CT microscope using cavity-resonators equipped with small field gradient coils

International Nuclear Information System (INIS)

Miki, T.; Murata, T.; Kumai, H.; Yamashiro, A.

1996-01-01

Cylindrical cavity resonators equipped with field gradient coils were developed for two-dimensional EPR-CT microscope systems. The field gradient coils lie in four (or six) thin metal tubes placed along the direction of the microwave magnetic field in the cavity to minimize impact on the resonator's quality factor. Two pairs of the tubes carry a 100 kHz current for magnetic field modulation. This cavity has high spin-detection sensitivity and can provide EPR images with submillimeter resolution. In order to reconstruct better images from fewer projections, we used an algebraic reconstruction technique (ART) for the two-dimensional image reconstruction. The ART method may be suitable for not only spectral-spatial two-dimensional EPR imaging, but also spatio-temporal EPR imaging in dynamic spin systems. (author)

Direct comparison of high-temporal-resolution CINE MRI with Doppler ultrasound for assessment of diastolic dysfunction in mice.

Science.gov (United States)

Roberts, Thomas A; Price, Anthony N; Jackson, Laurence H; Taylor, Valerie; David, Anna L; Lythgoe, Mark F; Stuckey, Daniel J

2017-10-01

Diastolic dysfunction is a sensitive early indicator of heart failure and can provide additional data to conventional measures of systolic function. Transmitral Doppler ultrasound, which measures the one-dimensional flow of blood through the mitral valve, is currently the preferred method for the measurement of diastolic function, but the measurement of the left ventricular volume changes using high-temporal-resolution cinematic magnetic resonance imaging (CINE MRI) is an alternative approach which is emerging as a potentially more robust and user-independent technique. Here, we investigated the performance of high-temporal-resolution CINE MRI and compared it with ultrasound for the detection of diastolic dysfunction in a mouse model of myocardial infarction. An in-house, high-temporal-resolution, retrospectively gated CINE sequence was developed with a temporal resolution of 1 ms. Diastolic function in mice was assessed using a custom-made, open-source reconstruction package. Early (E) and late (A) left ventricular filling phases were easily identifiable, and these measurements were compared directly with high-frequency, pulsed-wave, Doppler ultrasound measurements of mitral valve inflow. A repeatability study established that high-temporal-resolution CINE MRI and Doppler ultrasound showed comparable accuracy when measuring E/A in normal control mice. However, when applied in a mouse model of myocardial infarction, high-temporal-resolution CINE MRI indicated diastolic heart failure (E/A = 0.94 ± 0.11), whereas ultrasound falsely detected normal cardiac function (E/A = 1.21 ± 0.11). The addition of high-temporal-resolution CINE MRI to preclinical imaging studies enhances the library of sequences available to cardiac researchers and potentially identifies diastolic heart failure early in disease progression. © 2017 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.

Nitrogen detected TROSY at high field yields high resolution and sensitivity for protein NMR

Energy Technology Data Exchange (ETDEWEB)

Takeuchi, Koh [National Institute for Advanced Industrial Science and Technology, Molecular Profiling Research Center for Drug Discovery (Japan); Arthanari, Haribabu [Harvard Medical School, Department of Biochemistry and Molecular Pharmacology (United States); Shimada, Ichio, E-mail: shimada@iw-nmr.f.u-tokyo.ac.jp [National Institute for Advanced Industrial Science and Technology, Molecular Profiling Research Center for Drug Discovery (Japan); Wagner, Gerhard, E-mail: gerhard-wagner@hms.harvard.edu [Harvard Medical School, Department of Biochemistry and Molecular Pharmacology (United States)

2015-12-15

Detection of {sup 15}N in multidimensional NMR experiments of proteins has sparsely been utilized because of the low gyromagnetic ratio (γ) of nitrogen and the presumed low sensitivity of such experiments. Here we show that selecting the TROSY components of proton-attached {sup 15}N nuclei (TROSY {sup 15}N{sub H}) yields high quality spectra in high field magnets (>600 MHz) by taking advantage of the slow {sup 15}N transverse relaxation and compensating for the inherently low {sup 15}N sensitivity. The {sup 15}N TROSY transverse relaxation rates increase modestly with molecular weight but the TROSY gain in peak heights depends strongly on the magnetic field strength. Theoretical simulations predict that the narrowest line width for the TROSY {sup 15}N{sub H} component can be obtained at 900 MHz, but sensitivity reaches its maximum around 1.2 GHz. Based on these considerations, a {sup 15}N-detected 2D {sup 1}H–{sup 15}N TROSY-HSQC ({sup 15}N-detected TROSY-HSQC) experiment was developed and high-quality 2D spectra were recorded at 800 MHz in 2 h for 1 mM maltose-binding protein at 278 K (τ{sub c} ∼ 40 ns). Unlike for {sup 1}H detected TROSY, deuteration is not mandatory to benefit {sup 15}N detected TROSY due to reduced dipolar broadening, which facilitates studies of proteins that cannot be deuterated, especially in cases where production requires eukaryotic expression systems. The option of recording {sup 15}N TROSY of proteins expressed in H{sub 2}O media also alleviates the problem of incomplete amide proton back exchange, which often hampers the detection of amide groups in the core of large molecular weight proteins that are expressed in D{sub 2}O culture media and cannot be refolded for amide back exchange. These results illustrate the potential of {sup 15}N{sub H}-detected TROSY experiments as a means to exploit the high resolution offered by high field magnets near and above 1 GHz.

High resolution Neutron and Synchrotron Powder Diffraction

International Nuclear Information System (INIS)

Hewat, A.W.

1986-01-01

The use of high-resolution powder diffraction has grown rapidly in the past years, with the development of Rietveld (1967) methods of data analysis and new high-resolution diffractometers and multidetectors. The number of publications in this area has increased from a handful per year until 1973 to 150 per year in 1984, with a ten-year total of over 1000. These papers cover a wide area of solid state-chemistry, physics and materials science, and have been grouped under 20 subject headings, ranging from catalysts to zeolites, and from battery electrode materials to pre-stressed superconducting wires. In 1985 two new high-resolution diffractometers are being commissioned, one at the SNS laboratory near Oxford, and one at the ILL in Grenoble. In different ways these machines represent perhaps the ultimate that can be achieved with neutrons and will permit refinement of complex structures with about 250 parameters and unit cell volumes of about 2500 Angstrom/sp3/. The new European Synchotron Facility will complement the Grenoble neutron diffractometers, and extend the role of high-resolution powder diffraction to the direct solution of crystal structures, pioneered in Sweden

High resolution (transformers.

Science.gov (United States)

Garcia-Souto, Jose A; Lamela-Rivera, Horacio

2006-10-16

A novel fiber-optic interferometric sensor is presented for vibrations measurements and analysis. In this approach, it is shown applied to the vibrations of electrical structures within power transformers. A main feature of the sensor is that an unambiguous optical phase measurement is performed using the direct detection of the interferometer output, without external modulation, for a more compact and stable implementation. High resolution of the interferometric measurement is obtained with this technique (transformers are also highlighted.

High-resolution wavefront control of high-power laser systems

International Nuclear Information System (INIS)

Brase, J.; Brown, C.; Carrano, C.; Kartz, M.; Olivier, S.; Pennington, D.; Silva, D.

1999-01-01

Nearly every new large-scale laser system application at LLNL has requirements for beam control which exceed the current level of available technology. For applications such as inertial confinement fusion, laser isotope separation, laser machining, and laser the ability to transport significant power to a target while maintaining good beam quality is critical. There are many ways that laser wavefront quality can be degraded. Thermal effects due to the interaction of high-power laser or pump light with the internal optical components or with the ambient gas are common causes of wavefront degradation. For many years, adaptive optics based on thing deformable glass mirrors with piezoelectric or electrostrictive actuators have be used to remove the low-order wavefront errors from high-power laser systems. These adaptive optics systems have successfully improved laser beam quality, but have also generally revealed additional high-spatial-frequency errors, both because the low-order errors have been reduced and because deformable mirrors have often introduced some high-spatial-frequency components due to manufacturing errors. Many current and emerging laser applications fall into the high-resolution category where there is an increased need for the correction of high spatial frequency aberrations which requires correctors with thousands of degrees of freedom. The largest Deformable Mirrors currently available have less than one thousand degrees of freedom at a cost of approximately $1M. A deformable mirror capable of meeting these high spatial resolution requirements would be cost prohibitive. Therefore a new approach using a different wavefront control technology is needed. One new wavefront control approach is the use of liquid-crystal (LC) spatial light modulator (SLM) technology for the controlling the phase of linearly polarized light. Current LC SLM technology provides high-spatial-resolution wavefront control, with hundreds of thousands of degrees of freedom, more

High resolution optical DNA mapping

Science.gov (United States)

Baday, Murat

Many types of diseases including cancer and autism are associated with copy-number variations in the genome. Most of these variations could not be identified with existing sequencing and optical DNA mapping methods. We have developed Multi-color Super-resolution technique, with potential for high throughput and low cost, which can allow us to recognize more of these variations. Our technique has made 10--fold improvement in the resolution of optical DNA mapping. Using a 180 kb BAC clone as a model system, we resolved dense patterns from 108 fluorescent labels of two different colors representing two different sequence-motifs. Overall, a detailed DNA map with 100 bp resolution was achieved, which has the potential to reveal detailed information about genetic variance and to facilitate medical diagnosis of genetic disease.

High-resolution magnetic resonance imaging of the ankle: Normal anatomy

Energy Technology Data Exchange (ETDEWEB)

Hajek, P.C.; Baker, L.L.; Bjorkengren, A.; Sartoris, D.J.; Resnick, D.; Neumann, C.H.

1986-10-01

An imaging-anatomic correlative study of ankle anatomy based upon six healthy adults and six fresh cadaveric specimens was performed to evaluate the diagnostic capabilities of magnetic resonance imaging CMRI). Optimal pulsing sequences and imaging planes for various structures of interest were established. MRI afforded exquisite depiction of anatomic detial, particularly the diagnostically important collateral ligaments. Limitations in the ability to delineate the joint capsule and articular cartilage were documented, with the former detectable only on T2 weighted images in the presence of synovial fluid.

Detector tests in a high magnetic field and muon spectrometer triggering studies on a small prototype for an LHC experiment

CERN Document Server

Ambrosi, G; Basile, M; Battiston, R; Bergsma, F; Castro, H; Cifarelli, Luisa; Cindolo, F; Contin, A; De Pasquale, S; Gálvez, J; Gentile, S; Giusti, P; Laurent, G; Levi, G; Lin, Q; Maccarrone, G D; Mattern, D; Nania, R; Rivera, F; Schioppa, M; Sharma, A; CERN. Geneva. Detector Research and Development Committee

1990-01-01

The "Large Area Devices" group of the LAA project is working on R&D for muon detection at a future super-collider. New detectors are under development and the design of a muon spectrometer for an LHC experiment is under study. Our present choice is for a compact, high field, air-core toroidal muon spectrometer. Good momentum resolution is achievable in this compact solution, with at least one plane of detection elements inside the high field region. A new detector, the Blade Chamber, making use of blades instead of wires, has been developed for the forward and backward regions of the spectrometer, where polar coordinate readings are desirable.The assembling of a CERN high energy beam line, equipped with high resolution drift chambers and a strong field magnet could give us the opportunity to test our chambers in a high magnetic field and to study the muon trigger capabilities of a spectrometer, like the one proposed, on a small prototype.

Metabolomics by Proton High-Resolution Magic-Angle-Spinning Nuclear Magnetic Resonance of Tomato Plants Treated with Two Secondary Metabolites Isolated from Trichoderma.

Science.gov (United States)

Mazzei, Pierluigi; Vinale, Francesco; Woo, Sheridan Lois; Pascale, Alberto; Lorito, Matteo; Piccolo, Alessandro

2016-05-11

Trichoderma fungi release 6-pentyl-2H-pyran-2-one (1) and harzianic acid (2) secondary metabolites to improve plant growth and health protection. We isolated metabolites 1 and 2 from Trichoderma strains, whose different concentrations were used to treat seeds of Solanum lycopersicum. The metabolic profile in the resulting 15 day old tomato leaves was studied by high-resolution magic-angle-spinning nuclear magnetic resonance (HRMAS NMR) spectroscopy directly on the whole samples without any preliminary extraction. Principal component analysis (PCA) of HRMAS NMR showed significantly enhanced acetylcholine and γ-aminobutyric acid (GABA) content accompanied by variable amount of amino acids in samples treated with both Trichoderma secondary metabolites. Seed germination rates, seedling fresh weight, and the metabolome of tomato leaves were also dependent upon doses of metabolites 1 and 2 treatments. HRMAS NMR spectroscopy was proven to represent a rapid and reliable technique for evaluating specific changes in the metabolome of plant leaves and calibrating the best concentration of bioactive compounds required to stimulate plant growth.

High-Resolution Electronics: Spontaneous Patterning of High-Resolution Electronics via Parallel Vacuum Ultraviolet (Adv. Mater. 31/2016).

Science.gov (United States)

Liu, Xuying; Kanehara, Masayuki; Liu, Chuan; Sakamoto, Kenji; Yasuda, Takeshi; Takeya, Jun; Minari, Takeo

2016-08-01

On page 6568, T. Minari and co-workers describe spontaneous patterning based on the parallel vacuum ultraviolet (PVUV) technique, enabling the homogeneous integration of complex, high-resolution electronic circuits, even on large-scale, flexible, transparent substrates. Irradiation of PVUV to the hydrophobic polymer surface precisely renders the selected surface into highly wettable regions with sharply defined boundaries, which spontaneously guides a metal nanoparticle ink into a series of circuit lines and gaps with the widths down to a resolution of 1 μm. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High resolution UV spectroscopy and laser-focused nanofabrication

NARCIS (Netherlands)

Myszkiewicz, G.

2005-01-01

This thesis combines two at first glance different techniques: High Resolution Laser Induced Fluorescence Spectroscopy (LIF) of small aromatic molecules and Laser Focusing of atoms for Nanofabrication. The thesis starts with the introduction to the high resolution LIF technique of small aromatic

Optimal design of a double-sided linear motor with a multi-segmented trapezoidal magnet array for a high precision positioning system

International Nuclear Information System (INIS)

Lee, Moon G.; Gweon, Dae-Gab

2004-01-01

A comparative analysis is performed for linear motors adopting conventional and multi-segmented trapezoidal (MST) magnet arrays, respectively, for a high-precision positioning system. The proposed MST magnet array is a modified version of a Halbach magnet array. The MST array has trapezoidal magnets with variable shape and dimensions while the Halbach magnet array generally has a rectangular magnet with identical dimensions. We propose a new model that can describe the magnetic field resulting from the complex-shaped magnets. The model can be applied to both MST and conventional magnet arrays. Using the model, a design optimization of the two types of linear motors is performed and compared. The magnet array with trapezoidal magnets can produce more force than one with rectangular magnets when they are arrayed in a linear motor where there is a yoke with high permeability. After the optimization and comparison, we conclude that the linear motor with the MST magnet array can generate more actuating force per volume than the motor with the conventional array. In order to satisfy the requirements of next generation systems such as high resolution, high speed, and long stroke, the use of a linear motor with a MST array as an actuator in a high precision positioning system is recommended from the results obtained here

High-resolution spectrometer at PEP

International Nuclear Information System (INIS)

Weiss, J.M.; HRS Collaboration.

1982-01-01

A description is presented of the High Resolution Spectrometer experiment (PEP-12) now running at PEP. The advanced capabilities of the detector are demonstrated with first physics results expected in the coming months

A large acceptance, high-resolution detector for rare K sup + -decay experiments

CERN Document Server

Appel, R; Bassalleck, B; Battiste, E; Bergman, D R; Boesiger, K; Brown, D N; Castillo, V; Cheung, N; Dhawan, S; Do, H; Egger, J; Eilerts, S W; Felder, C; Fischer, H; Gach, H M; Giles, R; Gninenko, S N; Herold, W D; Hotmer, J E; Issakov, V V; Karavichev, O V; Kaspar, H; Kraus, D E; Lazarus, D M; Lebedev, V A; Leipuner, L; Lichard, P; Lowe, J; Lozano, J; Lu, T; Ma, H; Magurno, B; Majid, W; Menzel, W; Miller, C S; Nickelson, M; Ober, I; Pile, P H; Pislak, S; Poblaguev, A A; Pomianowski, P A; Postoev, V E; Proskurjakov, A L; Rehak, P; Robmann, P; Schmid, B; Sher, A; Sher, A; Shunko, E; Steiner, S; Stever, T L; Stotzer, R W; Suhov, V V; Thompson, J A; Truöl, P; Valine, C M; Weyer, H; Wolfe, D M; Zeller, M E

2002-01-01

The detector of the E865-collaboration at the Brookhaven-AGS described here combines a magnetic spectrometer for the charged decay products of 6 GeV/c K sup + with excellent electromagnetic calorimetry and efficient particle identification for electrons and muons. Its high-resolution, large acceptance and high rate capability made it well suited for the study of extremely rare or forbidden decays with multi-leptonic final states such as K sup +-> pi sup +mu sup + e sup - , K sup +-> pi sup + l sup + l sup - , K sup +->l sup +nu sub l e sup - e sup + and K sup +-> pi sup +pi sup - e sup +nu sub e down to branching ratios below 10 sup - sup 1 sup 1 in an intense K sup + beam (approx 10 sup 8 per AGS spill).

A large acceptance, high-resolution detector for rare K{sup +}-decay experiments

Energy Technology Data Exchange (ETDEWEB)

Appel, R.; Atoyan, G.S.; Bassalleck, B.; Battiste, E.; Bergman, D.R.; Boesiger, K.; Brown, D.N.; Castillo, V.; Cheung, N.; Dhawan, S.; Do, H.; Egger, J.; Eilerts, S.W.; Felder, C.; Fischer, H.; Gach, H.M.; Giles, R.; Gninenko, S.N.; Herold, W.D.; Hotmer, J.E.; Issakov, V.V.; Karavichev, O.V.; Kaspar, H.; Kraus, D.E.; Lazarus, D.M. E-mail: lazarus@bnl.gov; Lebedev, V.A.; Leipuner, L.; Lichard, P.; Lowe, J.; Lozano, J.; Lu, T.; Ma, H.; Magurno, B.; Majid, W.; Menzel, W.; Miller, C.S.; Nickelson, M.; Ober, I.; Pile, P.H.; Pislak, S.; Poblaguev, A.A.; Pomianowski, P.; Postoev, V.E.; Proskurjakov, A.L.; Rehak, P.; Robmann, P.; Schmid, B.; Sher, A.; Sher, Aleksey; Shunko, E.; Steiner, S.; Stever, T.L.; Stotzer, R.W.; Suhov, V.V.; Thompson, J.A.; Truoel, P. E-mail: truoel@phyzik.unizh.ch; Valine, C.; Weyer, H.; Wolfe, D.M.; Zeller, M.E

2002-03-01

The detector of the E865-collaboration at the Brookhaven-AGS described here combines a magnetic spectrometer for the charged decay products of 6 GeV/c K{sup +} with excellent electromagnetic calorimetry and efficient particle identification for electrons and muons. Its high-resolution, large acceptance and high rate capability made it well suited for the study of extremely rare or forbidden decays with multi-leptonic final states such as K{sup +}{yields}{pi}{sup +}{mu}{sup +}e{sup -}, K{sup +}{yields}{pi}{sup +}l{sup +}l{sup -}, K{sup +}{yields}l{sup +}{nu}{sub l}e{sup -}e{sup +} and K{sup +}{yields}{pi}{sup +}{pi}{sup -}e{sup +}{nu}{sub e} down to branching ratios below 10{sup -11} in an intense K{sup +} beam ({approx}10{sup 8} per AGS spill)

High-Field Accelerator Magnets

International Nuclear Information System (INIS)

Rijk, G de

2014-01-01

In this lecture an overview is given of the present technology for high field accelerator magnets. We indicate how to get high fields and what are the most important parameters. The available conductors and their limitations are presented followed by the most relevant types of coils and support structures. We conclude by showing a number of recent examples of development magnets which are either pure R&D objects or models for the LHC luminosity upgrade

High-resolution structure of the native histone octamer

International Nuclear Information System (INIS)

Wood, Christopher M.; Nicholson, James M.; Lambert, Stanley J.; Chantalat, Laurent; Reynolds, Colin D.; Baldwin, John P.

2005-01-01

The high-resolution (1.90 Å) model of the native histone octamer allows structural comparisons to be made with the nucleosome-core particle, along with an identification of a likely core-histone binding site. Crystals of native histone octamers (H2A–H2B)–(H4–H3)–(H3′–H4′)–(H2B′–H2A′) from chick erythrocytes in 2 M KCl, 1.35 M potassium phosphate pH 6.9 diffract X-rays to 1.90 Å resolution, yielding a structure with an R work value of 18.7% and an R free of 22.2%. The crystal space group is P6 5 , the asymmetric unit of which contains one complete octamer. This high-resolution model of the histone-core octamer allows further insight into intermolecular interactions, including water molecules, that dock the histone dimers to the tetramer in the nucleosome-core particle and have relevance to nucleosome remodelling. The three key areas analysed are the H2A′–H3–H4 molecular cluster (also H2A–H3′–H4′), the H4–H2B′ interaction (also H4′–H2B) and the H2A′–H4 β-sheet interaction (also H2A–H4′). The latter of these three regions is important to nucleosome remodelling by RNA polymerase II, as it is shown to be a likely core-histone binding site, and its disruption creates an instability in the nucleosome-core particle. A majority of the water molecules in the high-resolution octamer have positions that correlate to similar positions in the high-resolution nucleosome-core particle structure, suggesting that the high-resolution octamer model can be used for comparative studies with the high-resolution nucleosome-core particle

Design of mirror and monochromator crystals for a high-resolution multiwavelength anomalous diffraction beam line on a bending magnet at the ESRF

International Nuclear Information System (INIS)

Roth, M.; Ferrer, J.; Simon, J.; Geissler, E.

1992-01-01

High intensity for diffraction experiments with high-energy resolution on an intense x-ray beam, like the bending magnet beam lines at the ESRF, requires a strict control of the curvature of the optical elements placed in the beam for geometrical focusing and for wavelength monochromatization. Unwanted curvatures can come from nonuniform and variable heating of the optical elements produced by the absorption of x rays. To design the CRG/D2AM beam line described in the accompanying paper, some new techniques were developed to control these effects based on geometrical, i.e., topological, considerations. (1) Cooling of the entrance mirror: longitudinal curvature can be strongly reduced by cooling the mirror from the sides (and not from the rear) and only near the reflecting surface (i.e., not over the whole lateral surface). The cooling can be achieved for instance with an isothermal liquid Ga eutectic bath. (2) Cooling of the first single-crystal Si monochromator: because of the size of the crystal, only cooling from the rear is conceivable in this case. It can be shown by calculation that the curvature due to the front-to-rear gradient can be exactly compensated by the thermal expansion of a metallic layer at the rear of the crystal, having a larger expansion coefficient than Si

Use of an ultra-high resolution magnetic spectrograph for materials research

NARCIS (Netherlands)

Boerma, DO; Arnoldbik, WM; Wolfswinkel, W; Balogh, AG; Walter, G

1997-01-01

A brief description is given of a magnetic spectrograph for RBS and ERD analysis with MeV beams, delivered by a Tandem accelerator. With a number of examples of thin layer analysis it is shown that the spectrograph is uniquely suited for the measurement of concentration depth profiles up to a depth

Technical aspects: development, manufacture and installation of a cryo-cooled HTS coil system for high-resolution in-vivo imaging of the mouse at 1.5 T.

Science.gov (United States)

Ginefri, Jean-Christophe; Poirier-Quinot, Marie; Girard, Olivier; Darrasse, Luc

2007-09-01

Signal-to-noise ratio improvement is of major importance to achieve microscopic spatial resolution in magnetic resonance experiments. Magnetic resonance imaging of small animals is particularly concerned since it typically requires voxels of less than (100 microm)(3) to observe the small anatomical structures having size reduction by a factor of more than 10 as compared to human being. The signal-to-noise ratio can be increased by working at high static magnetic field strengths, but the biomedical interest of such high-field systems may be limited due to field-dependent contrast mechanisms and severe technological difficulties. An alternative approach that allows working in clinical imaging system is to improve the sensitivity of the radio-frequency receiver coil. This can be done using small cryogenically operated coils made either of copper or high-temperature superconducting material. We report the technological development of cryo-cooled superconducting coils for high-resolution imaging in a whole-body magnetic resonance scanner operating at 1.5 T. The technological background supporting this development is first addressed, including HTS coil design, simulation tools, cryogenic mean description and electrical characterization procedure. To illustrate the performances of superconducting coils for magnetic resonance imaging at intermediate field strength, in-vivo mouse images of various anatomic sites acquired with a 12 mm diameter cryo-cooled superconducting coil are presented.

Requirements on high resolution detectors

Energy Technology Data Exchange (ETDEWEB)

Koch, A. [European Synchrotron Radiation Facility, Grenoble (France)

1997-02-01

For a number of microtomography applications X-ray detectors with a spatial resolution of 1 {mu}m are required. This high spatial resolution will influence and degrade other parameters of secondary importance like detective quantum efficiency (DQE), dynamic range, linearity and frame rate. This note summarizes the most important arguments, for and against those detector systems which could be considered. This article discusses the mutual dependencies between the various figures which characterize a detector, and tries to give some ideas on how to proceed in order to improve present technology.

High-resolution magnetic resonance imaging reveals nuclei of the human amygdala: manual segmentation to automatic atlas

DEFF Research Database (Denmark)

Saygin, Z M; Kliemann, D; Iglesias, J. E.

2017-01-01

The amygdala is composed of multiple nuclei with unique functions and connections in the limbic system and to the rest of the brain. However, standard in vivo neuroimaging tools to automatically delineate the amygdala into its multiple nuclei are still rare. By scanning postmortem specimens at high...... resolution (100-150µm) at 7T field strength (n = 10), we were able to visualize and label nine amygdala nuclei (anterior amygdaloid, cortico-amygdaloid transition area; basal, lateral, accessory basal, central, cortical medial, paralaminar nuclei). We created an atlas from these labels using a recently...... developed atlas building algorithm based on Bayesian inference. This atlas, which will be released as part of FreeSurfer, can be used to automatically segment nine amygdala nuclei from a standard resolution structural MR image. We applied this atlas to two publicly available datasets (ADNI and ABIDE...

High-resolution clean-sc

NARCIS (Netherlands)

Sijtsma, P.; Snellen, M.

2016-01-01

In this paper a high-resolution extension of CLEAN-SC is proposed: HR-CLEAN-SC. Where CLEAN-SC uses peak sources in “dirty maps” to define so-called source components, HR-CLEAN-SC takes advantage of the fact that source components can likewise be derived from points at some distance from the peak,

A new beauty for 'ADONE': a high resolution powder diffractometer for synchrotron radiation experiments

International Nuclear Information System (INIS)

Burattini, E.; Simeoni, S.

1991-01-01

A high resolution powder diffractometer, connected to the wiggler magnet line BX1, is now operative at the Adone storage ring in Frascati. A Si channel-cut monochromator on the line allows operation in the range 1-3 A. To achieve the desired high resolution in the diffraction spectra, a 'triple-axis configuration' has been chosen: a vertical standing goniometer supports a flat Ge(111) crystal analyzer on the 2O arm. With this configuration, a value of less than 0.02 o for the FWHM of the diffraction peaks has been reached. The special design solutions adopted for a Seifer MZ VI goniometer and the microstep technology used in the stepper motor actuation assure a mechanical resolution better than 0.001 o . A special supporting table, with six degrees of freedom, has been made for the diffractometer orientation in front of the X-ray beam. An IBM-PC is dedicated to the diffractometer positioning control and preliminary data collection. As a Macintosh IICX provides for the data processing, a special software package, named 'Mac Dust', has been developed and is continuously updated. The first experimental results collected on-line during the instrument check-up are presented. (author) 5 figs., 1 tab., 11 refs

Planning for shallow high resolution seismic surveys

CSIR Research Space (South Africa)

Fourie, CJS

2008-11-01

Full Text Available of the input wave. This information can be used in conjunction with this spreadsheet to aid the geophysicist in designing shallow high resolution seismic surveys to achieve maximum resolution and penetration. This Excel spreadsheet is available free from...

Echo planar perfusion imaging with high spatial and temporal resolution: methodology and clinical aspects

International Nuclear Information System (INIS)

Bitzer, M.; Klose, U.; Naegele, T.; Friese, S.; Kuntz, R.; Voigt, K.; Fetter, M.; Opitz, H.

1999-01-01

The purpose of the present study was to analyse specific advantages of calculated parameter images and their limitations using an optimized echo-planar imaging (EPI) technique with high spatial and temporal resolution. Dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) was performed in 12 patients with cerebrovascular disease and in 13 patients with brain tumours. For MR imaging of cerebral perfusion an EPI sequence was developed which provides a temporal resolution of 0.68 s for three slices with a 128 x 128 image matrix. To evaluate DSC-MRI, the following parameter images were calculated pixelwise: (1) Maximum signal reduction (MSR); (2) maximum signal difference (ΔSR); (3) time-to-peak (T p ); and (4) integral of signal-intensity-time curve until T p (S Int ). The MSR maps were superior in the detection of acute infarctions and ΔSR maps in the delineation of vasogenic brain oedema. The time-to-peak (T p ) maps seemed to be highly sensitive in the detection of poststenotic malperfused brain areas (sensitivity 90 %). Hyperperfused areas of brain tumours were detectable down to a diameter of 1 cm with high sensitivity (> 90 %). Distinct clinical and neuroradiological conditions revealed different suitabilities for the parameter images. The time-to-peak (T p ) maps may be an important advantage in the detection of poststenotic ''areas at risk'', due to an improved temporal resolution using an EPI technique. With regard to spatial resolution, a matrix size of 128 x 128 is sufficient for all clinical conditions. According to our results, a further increase in matrix size would not improve the spatial resolution in DSC-MRI, since the degree of the vascularization of lesions and the susceptibility effect itself seem to be the limiting factors. (orig.)

Prevalence Study of Proximal Vertebral Artery Stenosis Using High-Resolution Contrast-Enhanced Magnetic Resonance Angiography

International Nuclear Information System (INIS)

Kim, S.H.; Lee, J.S.; Kwon, O.K.; Han, M.K.; Kim, J.H.

2005-01-01

Purpose: To evaluate the prevalence of proximal vertebral artery stenosis, compared with those of the distal vertebral/basilar artery and extracranial internal carotid artery, in a large population of stroke and non-stroke patients. Material and Methods: Nine-hundred-and-thirty-five patients who underwent high-resolution contrast-enhanced magnetic resonance angiography in a regional general hospital were categorized into six groups based on neurological symptoms and disease: an asymptomatic group (n ∼ 182), a minor symptom group with headache or dizziness (n ∼ 519), a cardiac group with coronary artery steno-occlusive disease (n ∼ 15), a hemorrhagic group with old cerebral hemorrhage (n ∼ 26), an anterior circulation infarct group (n ∼ 121), and posterior circulation infarct group (n ∼ 72). Prevalence of stenosis of the proximal vertebral artery, distal vertebral/basilar artery, and internal carotid artery was analyzed. Results: The prevalence of stenosis of the proximal vertebral artery, distal vertebral/basilar artery, and internal carotid artery was 12.9%, 5.5%, and 7.2%, respectively, in the study population, and rose as the age increased (P <0.0001 for all arteries). The prevalence of stenosis of the proximal vertebral artery, distal vertebral/basilar artery, and internal carotid artery was 3.3%, 0.5%, and.1%, respectively, in the asymptomatic group; 8.3%, 2.1%, and 3.7%, respectively, in the minor symptom group; 13.3%, 6.7%, and 6.7%, respectively, in the cardiac group; 19.2%, 7.7%, and 7.7%, respectively, in the hemorrhagic group; 27.3%, 8.3%, and 25.6%, respectively, in the anterior circulation infarct group; and 44.4%, 36.1%, and 16.7%, respectively, in the posterior circulation infarct group. This increasing tendency of stenosis accordingly was statistically significant ( P <0.0001 for all arteries). Conclusion: The prevalence of proximal vertebral artery stenosis was highest, compared with those of the distal vertebral/basilar artery and

Magnetic polymer nanocomposites for sensing applications

KAUST Repository

Alfadhel, Ahmed

2014-11-01

We report the fabrication and characterization of magnetic polymer nanocomposites for a wide range of sensing applications. The composites are made of magnetic nanowires (NWs) incorporated into polymers such as polydimethylsiloxane (PDMS) or UV sensitive SU-S. The developed composites utilize the permanent magnetic behavior of the NWs, allowing remote operation without an additional magnetic field to magnetize the NWs, which simplifies miniaturization and integration in microsystems. In addition, the nanocomposite benefits from the easy patterning of the polymer leading to a corrosion resistant, highly elastic, and permanent magnetic material that can be used to develop highly sensitive systems. Nanocomposite pillars are realized and integrated on magnetic sensor elements to achieve highly sensitive and power efficient flow and tactile sensors. The developed flow sensor can detect air and water flow at a power consumption as little as SO nW and a resolution up to 15 μm/s with easily modifiable performance. A tactile sensor element prototype is realized using the same concept, where a pressure range of 0-169 kPa is detected with a resolution of up to 1.3 kPa. © 2014 IEEE.

Gamma-ray spectrometer system with high efficiency and high resolution

International Nuclear Information System (INIS)

Moss, C.E.; Bernard, W.; Dowdy, E.J.; Garcia, C.; Lucas, M.C.; Pratt, J.C.

1983-01-01

Our gamma-ray spectrometer system, designed for field use, offers high efficiency and high resolution for safeguards applications. The system consists of three 40% high-purity germanium detectors and a LeCroy 3500 data acquisition system that calculates a composite spectrum for the three detectors. The LeCroy 3500 mainframe can be operated remotely from the detector array with control exercised through modems and the telephone system. System performance with a mixed source of 125 Sb, 154 Eu, and 155 Eu confirms the expected efficiency of 120% with the overall resolution showing little degradation over that of the worst detector

High resolution inelastic electron scattering on 90Zr at low momentum transfer and strong fragmentation of the magnetic quadrupole strength

International Nuclear Information System (INIS)

Meuer, D.; Frey, R.; Hoffmann, D.H.H.; Richter, A.; Spamer, E.; Titze, O.; Knuepfer, W.

1980-01-01

High-resolution (FWHM approx. 30 keV) inelastic electron scattering on 90 Zr at low momentum transfer (0.20 -1 ) has been used to study magnetic transitions at excitation energies Esub(x) = 8-10 MeV. The experimental data were analyzed in the distorted-wave Born approximation (DWBA) with wave functions calculated in the random phase approximation (RPA). Three Jsup(π) = 1 + states have been identified Esub(x) = 8.233, 9.000 and 9.371 MeV. There is some indication of further very fragmented dipole strength and the upper limit for the total M1 strength in the investigated energy region is ΣB(M1)up 2 sub(K). It is much smaller than any theoretical prediction. Furthermore, a large number of 2 - states has been observed, with the center of gravity located at Esub(x) approx. 9 MeV. These states carry a total strength of ΣB(M2)up = 1000 μ 2 sub(K) x fm 2 . Their strong fragmentation is in qualitative agreement with theoretical calculations, but the deduced strength is much smaller than theoretically predicted. In addition the distributions of spacings and radiative widths of the 2 - states are consistent with a Wigner and a Porter-Thomas distribution, respectively. (orig.)

High resolution metric imaging payload

Science.gov (United States)

Delclaud, Y.

2017-11-01

Alcatel Space Industries has become Europe's leader in the field of high and very high resolution optical payloads, in the frame work of earth observation system able to provide military government with metric images from space. This leadership allowed ALCATEL to propose for the export market, within a French collaboration frame, a complete space based system for metric observation.

High-resolution X-ray diffraction studies of multilayers

DEFF Research Database (Denmark)

Christensen, Finn Erland; Hornstrup, Allan; Schnopper, H. W.

1988-01-01

High-resolution X-ray diffraction studies of the perfection of state-of-the-art multilayers are presented. Data were obtained using a triple-axis perfect-crystal X-ray diffractometer. Measurements reveal large-scale figure errors in the substrate. A high-resolution triple-axis set up is required...

Magnetic spectrometer Grand Raiden

International Nuclear Information System (INIS)

Fujiwara, M.; Akimune, H.; Daito, I.; Fujimura, H.; Fujita, Y.; Hatanaka, K.; Ikegami, H.; Katayama, I.; Nagayama, K.; Matsuoka, N.; Morinobu, S.; Noro, T.; Yoshimura, M.; Sakaguchi, H.; Sakemi, Y.; Tamii, A.; Yosoi, M.

1999-01-01

A high-resolution magnetic spectrometer called 'Grand Raiden' is operated at the RCNP ring cyclotron facility in Osaka for nuclear physics studies at intermediate energies. This magnetic spectrometer has excellent ion-optical properties. In the design of the spectrometer, the second-order dispersion matching condition has been taken into account, and almost all the aberration terms such as (x vertical bar θ 3 ), (x vertical bar θφ 2 ), (x vertical bar θ 2 δ) and (x vertical bar θδ 2 ) in a third-order matrix calculation are optimized. A large magnetic rigidity of the spectrometer (K = 1400 MeV) gives a great advantage to measure the charge-exchange ( 3 He, t) reactions at 450 MeV. The ability of the high-resolution measurement has been demonstrated. Various coincidence measurements are performed to study the nuclear structures of highly excited states through decay properties of nuclear levels following nuclear reactions at intermediate energies

Isotope specific resolution recovery image reconstruction in high resolution PET imaging

Energy Technology Data Exchange (ETDEWEB)

Kotasidis, Fotis A. [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva, Switzerland and Wolfson Molecular Imaging Centre, MAHSC, University of Manchester, M20 3LJ, Manchester (United Kingdom); Angelis, Georgios I. [Faculty of Health Sciences, Brain and Mind Research Institute, University of Sydney, NSW 2006, Sydney (Australia); Anton-Rodriguez, Jose; Matthews, Julian C. [Wolfson Molecular Imaging Centre, MAHSC, University of Manchester, Manchester M20 3LJ (United Kingdom); Reader, Andrew J. [Montreal Neurological Institute, McGill University, Montreal QC H3A 2B4, Canada and Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King' s College London, St. Thomas’ Hospital, London SE1 7EH (United Kingdom); Zaidi, Habib [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva (Switzerland); Geneva Neuroscience Centre, Geneva University, CH-1205 Geneva (Switzerland); Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, PO Box 30 001, Groningen 9700 RB (Netherlands)

2014-05-15

Purpose: Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measurements. As such, non-optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction, usually underestimating the true PSF owing to the difference in positron range. In high resolution brain and preclinical imaging, this effect is of particular importance since the PSFs become more positron range limited and isotope-specific PSFs can help maximize the performance benefit from using resolution recovery image reconstruction algorithms. Methods: In this work, the authors used a printing technique to simultaneously measure multiple point sources on the High Resolution Research Tomograph (HRRT), and the authors demonstrated the feasibility of deriving isotope-dependent system matrices from fluorine-18 and carbon-11 point sources. Furthermore, the authors evaluated the impact of incorporating them within RM image reconstruction, using carbon-11 phantom and clinical datasets on the HRRT. Results: The results obtained using these two isotopes illustrate that even small differences in positron range can result in different PSF maps, leading to further improvements in contrast recovery when used in image reconstruction. The difference is more pronounced in the centre of the field-of-view where the full width at half maximum (FWHM) from the positron range has a larger contribution to the overall FWHM compared to the edge where the parallax error dominates the overall FWHM. Conclusions: Based on the proposed methodology, measured isotope-specific and spatially variant PSFs can be reliably derived and used for improved spatial resolution and variance performance in resolution

Isotope specific resolution recovery image reconstruction in high resolution PET imaging

International Nuclear Information System (INIS)

Kotasidis, Fotis A.; Angelis, Georgios I.; Anton-Rodriguez, Jose; Matthews, Julian C.; Reader, Andrew J.; Zaidi, Habib

2014-01-01

Purpose: Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measurements. As such, non-optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction, usually underestimating the true PSF owing to the difference in positron range. In high resolution brain and preclinical imaging, this effect is of particular importance since the PSFs become more positron range limited and isotope-specific PSFs can help maximize the performance benefit from using resolution recovery image reconstruction algorithms. Methods: In this work, the authors used a printing technique to simultaneously measure multiple point sources on the High Resolution Research Tomograph (HRRT), and the authors demonstrated the feasibility of deriving isotope-dependent system matrices from fluorine-18 and carbon-11 point sources. Furthermore, the authors evaluated the impact of incorporating them within RM image reconstruction, using carbon-11 phantom and clinical datasets on the HRRT. Results: The results obtained using these two isotopes illustrate that even small differences in positron range can result in different PSF maps, leading to further improvements in contrast recovery when used in image reconstruction. The difference is more pronounced in the centre of the field-of-view where the full width at half maximum (FWHM) from the positron range has a larger contribution to the overall FWHM compared to the edge where the parallax error dominates the overall FWHM. Conclusions: Based on the proposed methodology, measured isotope-specific and spatially variant PSFs can be reliably derived and used for improved spatial resolution and variance performance in resolution

Isotope specific resolution recovery image reconstruction in high resolution PET imaging.

Science.gov (United States)

Kotasidis, Fotis A; Angelis, Georgios I; Anton-Rodriguez, Jose; Matthews, Julian C; Reader, Andrew J; Zaidi, Habib

2014-05-01

Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measurements. As such, non-optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction, usually underestimating the true PSF owing to the difference in positron range. In high resolution brain and preclinical imaging, this effect is of particular importance since the PSFs become more positron range limited and isotope-specific PSFs can help maximize the performance benefit from using resolution recovery image reconstruction algorithms. In this work, the authors used a printing technique to simultaneously measure multiple point sources on the High Resolution Research Tomograph (HRRT), and the authors demonstrated the feasibility of deriving isotope-dependent system matrices from fluorine-18 and carbon-11 point sources. Furthermore, the authors evaluated the impact of incorporating them within RM image reconstruction, using carbon-11 phantom and clinical datasets on the HRRT. The results obtained using these two isotopes illustrate that even small differences in positron range can result in different PSF maps, leading to further improvements in contrast recovery when used in image reconstruction. The difference is more pronounced in the centre of the field-of-view where the full width at half maximum (FWHM) from the positron range has a larger contribution to the overall FWHM compared to the edge where the parallax error dominates the overall FWHM. Based on the proposed methodology, measured isotope-specific and spatially variant PSFs can be reliably derived and used for improved spatial resolution and variance performance in resolution recovery image reconstruction. The

Defect mediated magnetic interaction and high Tc ferromagnetism in Co doped ZnO nanoparticles.

Science.gov (United States)

Pal, Bappaditya; Giri, P K

2011-10-01

Structural, optical and magnetic studies have been carried out for the Co-doped ZnO nanoparticles (NPs). ZnO NPs are doped with 3% and 5% Co using ball milling and ferromagnetism (FM) is studied at room temperature and above. A high Curie temperature (Tc) has been observed from the Co doped ZnO NPs. X-ray diffraction and high resolution transmission electron microscopy analysis confirm the absence of metallic Co clusters or any other phase different from würtzite-type ZnO. UV-visible absorption and photoluminescence studies on the doped samples show change in band structure and oxygen vacancy defects, respectively. Micro-Raman studies of doped samples shows defect related additional strong bands at 547 and 574 cm(-1) confirming the presence of oxygen vacancy defects in ZnO lattice. The field dependence of magnetization (M-H curve) measured at room temperature exhibits the clear M-H loop with saturation magnetization and coercive field of the order of 4-6 emu/g and 260 G, respectively. Temperature dependence of magnetization measurement shows sharp ferromagnetic to paramagnetic transition with a high Tc = 791 K for 3% Co doped ZnO NPs. Ferromagnetic ordering is interpreted in terms of overlapping of polarons mediated through oxygen vacancy defects based on the bound magnetic polaron (BMP) model. We show that the observed FM data fits well with the BMP model involving localised carriers and magnetic cations.

Thermodesorption studies of ammonium nitrate prills by high-resolution thermogravimetry

Energy Technology Data Exchange (ETDEWEB)

Kwok, Q.S.M.; Jones, D.E.G. [Natural Resources Canada, CANMET Canadian Explosives Research Laboratory, Ottawa, ON (Canada)

2003-07-01

Ammonium nitrate prills with fuel oil (ANFO) are commonly used in commercial explosives. The wettability of AN is influenced by porosity and surface area. To date, scanning electron microscopy (SEM), mercury porosimetry, and nuclear magnetic resonance (NMR) microscopy have been used to characterize prill porosities. This study used high-resolution thermogravimetry (TG) to investigate the thermodesorption of octane from ammonium nitrate (AN) prills of different porosities. Samples were immersed in octane. Samples of AN prills were monitored over a temperature range between 25 to 120 degrees C. Mass-loss curves were measured to determine the evaporation of excess liquids as well as the rate of octane thermodesorption from the pores and surfaces of the AN prills. An analysis of the curves suggested that the initial mass loss was caused by evaporation of the bulk liquid. The following step represented the thermodesorption of adsorbed octane on the surface of the AN remote from the monolayer. Properties of the surface liquid differed significantly from the bulk liquid as the adsorbate materials interacted with the solid surface. The study demonstrated that the quantity of octane desorbed in the steps correlated with the volume observed in the pores and the amount adsorbed on the surface. Results of the study were then compared with data obtained using SEM. It was concluded that high resolution TG can be used to characterize AN porosity and adsorption capacity. 16 refs., 1 tab., 5 figs.