Direct determination of phosphate sugars in biological material by (1)H high-resolution magic-angle-spinning NMR spectroscopy.

PubMed

Diserens, Gaëlle; Vermathen, Martina; Gjuroski, Ilche; Eggimann, Sandra; Precht, Christina; Boesch, Chris; Vermathen, Peter

2016-08-01

The study aim was to unambiguously assign nucleotide sugars, mainly UDP-X that are known to be important in glycosylation processes as sugar donors, and glucose-phosphates that are important intermediate metabolites for storage and transfer of energy directly in spectra of intact cells, as well as in skeletal muscle biopsies by (1)H high-resolution magic-angle-spinning (HR-MAS) NMR. The results demonstrate that sugar phosphates can be determined quickly and non-destructively in cells and biopsies by HR-MAS, which may prove valuable considering the importance of phosphate sugars in cell metabolism for nucleic acid synthesis. As proof of principle, an example of phosphate-sugar reaction and degradation kinetics after unfreezing the sample is shown for a cardiac muscle, suggesting the possibility to follow by HR-MAS NMR some metabolic pathways. Graphical abstract Glucose-phosphate sugars (Glc-1P and Glc-6P) detected in muscle by 1H HR-MAS NMR.

Chemical Shifts of the Carbohydrate Binding Domain of Galectin-3 from Magic Angle Spinning NMR and Hybrid Quantum Mechanics/Molecular Mechanics Calculations.

PubMed

Kraus, Jodi; Gupta, Rupal; Yehl, Jenna; Lu, Manman; Case, David A; Gronenborn, Angela M; Akke, Mikael; Polenova, Tatyana

2018-03-22

Magic angle spinning NMR spectroscopy is uniquely suited to probe the structure and dynamics of insoluble proteins and protein assemblies at atomic resolution, with NMR chemical shifts containing rich information about biomolecular structure. Access to this information, however, is problematic, since accurate quantum mechanical calculation of chemical shifts in proteins remains challenging, particularly for 15 N H . Here we report on isotropic chemical shift predictions for the carbohydrate recognition domain of microcrystalline galectin-3, obtained from using hybrid quantum mechanics/molecular mechanics (QM/MM) calculations, implemented using an automated fragmentation approach, and using very high resolution (0.86 Å lactose-bound and 1.25 Å apo form) X-ray crystal structures. The resolution of the X-ray crystal structure used as an input into the AF-NMR program did not affect the accuracy of the chemical shift calculations to any significant extent. Excellent agreement between experimental and computed shifts is obtained for 13 C α , while larger scatter is observed for 15 N H chemical shifts, which are influenced to a greater extent by electrostatic interactions, hydrogen bonding, and solvation.

Atomic-resolution structure of the CAP-Gly domain of dynactin on polymeric microtubules determined by magic angle spinning NMR spectroscopy.

PubMed

Yan, Si; Guo, Changmiao; Hou, Guangjin; Zhang, Huilan; Lu, Xingyu; Williams, John Charles; Polenova, Tatyana

2015-11-24

Microtubules and their associated proteins perform a broad array of essential physiological functions, including mitosis, polarization and differentiation, cell migration, and vesicle and organelle transport. As such, they have been extensively studied at multiple levels of resolution (e.g., from structural biology to cell biology). Despite these efforts, there remain significant gaps in our knowledge concerning how microtubule-binding proteins bind to microtubules, how dynamics connect different conformational states, and how these interactions and dynamics affect cellular processes. Structures of microtubule-associated proteins assembled on polymeric microtubules are not known at atomic resolution. Here, we report a structure of the cytoskeleton-associated protein glycine-rich (CAP-Gly) domain of dynactin motor on polymeric microtubules, solved by magic angle spinning NMR spectroscopy. We present the intermolecular interface of CAP-Gly with microtubules, derived by recording direct dipolar contacts between CAP-Gly and tubulin using double rotational echo double resonance (dREDOR)-filtered experiments. Our results indicate that the structure adopted by CAP-Gly varies, particularly around its loop regions, permitting its interaction with multiple binding partners and with the microtubules. To our knowledge, this study reports the first atomic-resolution structure of a microtubule-associated protein on polymeric microtubules. Our approach lays the foundation for atomic-resolution structural analysis of other microtubule-associated motors.

High-resolution molecular structure of a peptide in an amyloid fibril determined by magic angle spinning NMR spectroscopy

NASA Astrophysics Data System (ADS)

Jaroniec, Christopher P.; Macphee, Cait E.; Bajaj, Vikram S.; McMahon, Michael T.; Dobson, Christopher M.; Griffin, Robert G.

2004-01-01

Amyloid fibrils are self-assembled filamentous structures associated with protein deposition conditions including Alzheimer's disease and the transmissible spongiform encephalopathies. Despite the immense medical importance of amyloid fibrils, no atomic-resolution structures are available for these materials, because the intact fibrils are insoluble and do not form diffraction-quality 3D crystals. Here we report the high-resolution structure of a peptide fragment of the amyloidogenic protein transthyretin, TTR(105-115), in its fibrillar form, determined by magic angle spinning NMR spectroscopy. The structure resolves not only the backbone fold but also the precise conformation of the side chains. Nearly complete 13C and 15N resonance assignments for TTR(105-115) formed the basis for the extraction of a set of distance and dihedral angle restraints. A total of 76 self-consistent experimental measurements, including 41 restraints on 19 backbone dihedral angles and 35 13C-15N distances between 3 and 6 Å were obtained from 2D and 3D NMR spectra recorded on three fibril samples uniformly 13C, 15N-labeled in consecutive stretches of four amino acids and used to calculate an ensemble of peptide structures. Our results indicate that TTR(105-115) adopts an extended -strand conformation in the amyloid fibrils such that both the main- and side-chain torsion angles are close to their optimal values. Moreover, the structure of this peptide in the fibrillar form has a degree of long-range order that is generally associated only with crystalline materials. These findings provide an explanation of the unusual stability and characteristic properties of this form of polypeptide assembly.

Resolution enhancement in 13C and 15N magic-angle turning experiments with TPPM decoupling.

PubMed

McGeorge, G; Alderman, D W; Grant, D M

1999-03-01

Many solid-state spectra have been shown to have problems related to the poor proton decoupling of carbon nuclei in methylene groups under conditions of slow magic-angle turning. Two-pulse phase-modulation (TPPM) decoupling during the 2D PHORMAT chemical shift separation experiment is shown to be more effective in comparison to that obtainable at much higher spin rates using conventional CW decoupling. TPPM decoupling can also alleviate similar inadequacies when observing the 15N nucleus, particularly with NH2 groups. This is demonstrated in the 15N resonances of fully labeled l-arginine hydrochloride, where a line narrowing of about a factor of two was observed at moderate rotation rates. This significant advantage was also obtained at turning frequencies as low as 500 Hz. Copyright 1999 Academic Press.

New mechanistic insights regarding Pd/Cu catalysts for the Sonogashira reaction: HRMAS NMR studies of silica-immobilized systems.

PubMed

Posset, Tobias; Blümel, Janet

2006-07-05

The title technique, high-resolution magic angle spinning NMR of suspensions, constitutes a powerful new tool for investigating the structures and mobilities of immobilized species and, thus, for optimizing heterobimetallic catalyst systems, such as the Sonogashira coupling of terminal alkynes and aryl halides.

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

PubMed Central

Fuss, Taylor L.; Cheng, Leo L.

2016-01-01

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. PMID:27011205

Metabolomics by Proton High-Resolution Magic-Angle-Spinning Nuclear Magnetic Resonance of Tomato Plants Treated with Two Secondary Metabolites Isolated from Trichoderma.

PubMed

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.

Metabolic profiling of apples from different production systems before and after controlled atmosphere (CA) storage studied by 1H high resolution-magic angle spinning (HR-MAS) NMR.

PubMed

Vermathen, Martina; Marzorati, Mattia; Diserens, Gaëlle; Baumgartner, Daniel; Good, Claudia; Gasser, Franz; Vermathen, Peter

2017-10-15

Determination of metabolic alterations in apples induced by such processes as different crop protection strategies or storage, are of interest to assess correlations with fruit quality or fruit disorders. Preliminary results proposed the metabolic discrimination of apples from organic (BIO), integrated (IP) and low-input (LI) production. To determine contributions of temporal metabolic developments and to define the type of metabolic changes during storage, 1 H high resolution-magic angle spinning (HR-MAS) NMR spectroscopy of apple pulp was performed before and after two time points of controlled atmosphere storage. Statistical analysis revealed similar metabolic changes over time for IP-, LI- and BIO-samples, mainly decreasing lipid and sucrose, and increasing fructose, glucose and acetaldehyde levels, which are potential contributors to fruit aroma. Across the production systems, BIO apples had consistently higher levels of fructose and monomeric phenolic compounds but lower levels of condensed polyphenols than LI and IP apples, while the remaining metabolites assimilated. Copyright © 2017 Elsevier Ltd. All rights reserved.

1H magic-angle spinning NMR evolves as a powerful new tool for membrane proteins

NASA Astrophysics Data System (ADS)

Schubeis, Tobias; Le Marchand, Tanguy; Andreas, Loren B.; Pintacuda, Guido

2018-02-01

Building on a decade of continuous advances of the community, the recent development of very fast (60 kHz and above) magic-angle spinning (MAS) probes has revolutionised the field of solid-state NMR. This new spinning regime reduces the 1H-1H dipolar couplings, so that direct detection of the larger magnetic moment available from 1H is now possible at high resolution, not only in deuterated molecules but also in fully-protonated substrates. Such capabilities allow rapid "fingerprinting" of samples with a ten-fold reduction of the required sample amounts with respect to conventional approaches, and permit extensive, robust and expeditious assignment of small-to-medium sized proteins (up to ca. 300 residues), and the determination of inter-nuclear proximities, relative orientations of secondary structural elements, protein-cofactor interactions, local and global dynamics. Fast MAS and 1H detection techniques have nowadays been shown to be applicable to membrane-bound systems. This paper reviews the strategies underlying this recent leap forward in sensitivity and resolution, describing its potential for the detailed characterization of membrane proteins.

Controlling soliton excitations in Heisenberg spin chains through the magic angle.

PubMed

Lu, Jing; Zhou, Lan; Kuang, Le-Man; Sun, C P

2009-01-01

We study the nonlinear dynamics of collective excitation in an N -site XXZ quantum spin chain, which is manipulated by an oblique magnetic field. We show that, when the tilted field is applied along the magic angle, theta_{0}=+/-arccossqrt[13] , the anisotropic Heisenberg spin chain becomes isotropic and thus an freely propagating spin wave is stimulated. Also, in the regime of tilted angles larger and smaller than the magic angle, two types of nonlinear excitations appear: bright and dark solitons.

Magic-angle spinning NMR of intact bacteriophages: Insights into the capsid, DNA and their interface

NASA Astrophysics Data System (ADS)

Abramov, Gili; Morag, Omry; Goldbourt, Amir

2015-04-01

Bacteriophages are viruses that infect bacteria. They are complex macromolecular assemblies, which are composed of multiple protein subunits that protect genomic material and deliver it to specific hosts. Various biophysical techniques have been used to characterize their structure in order to unravel phage morphogenesis. Yet, most bacteriophages are non-crystalline and have very high molecular weights, in the order of tens of MegaDaltons. Therefore, complete atomic-resolution characterization on such systems that encompass both capsid and DNA is scarce. In this perspective article we demonstrate how magic-angle spinning solid-state NMR has and is used to characterize in detail bacteriophage viruses, including filamentous and icosahedral phage. We discuss the process of sample preparation, spectral assignment of both capsid and DNA and the use of chemical shifts and dipolar couplings to probe the capsid-DNA interface, describe capsid structure and dynamics and extract structural differences between viruses.

Structural Masquerade of Plesiomonas shigelloides Strain CNCTC 78/89 O-Antigen-High-Resolution Magic Angle Spinning NMR Reveals the Modified d-galactan I of Klebsiella pneumoniae.

PubMed

Ucieklak, Karolina; Koj, Sabina; Pawelczyk, Damian; Niedziela, Tomasz

2017-11-29

The high-resolution magic angle spinning nuclear magnetic resonance spectroscopy (HR-MAS NMR) analysis of Plesiomonas shigelloides 78/89 lipopolysaccharide directly on bacteria revealed the characteristic structural features of the O -acetylated polysaccharide in the NMR spectra. The O -antigen profiles were unique, yet the pattern of signals in the, spectra along with their ¹H, 13 C chemical shift values, resembled these of d-galactan I of Klebsiella pneumoniae . The isolated O- specific polysaccharide (O-PS) of P. shigelloides strain CNCTC 78/89 was investigated by ¹H and 13 C NMR spectroscopy, mass spectrometry and chemical methods. The analyses demonstrated that the P. shigelloides 78/89 O- PS is composed of →3)-α-d-Gal p -(1→3)-β-d-Gal f 2OAc-(1→ disaccharide repeating units. The O- acetylation was incomplete and resulted in a microheterogeneity of the O- antigen. This O- acetylation generates additional antigenic determinants within the O- antigen, forms a new chemotype, and contributes to the epitopes recognized by the O- serotype specific antibodies. The serological cross-reactivities further confirmed the inter-specific structural similarity of these O- antigens.

High-resolution diffusion and relaxation-edited magic angle spinning 1H NMR spectroscopy of intact liver tissue.

PubMed

Rooney, O M; Troke, J; Nicholson, J K; Griffin, J L

2003-11-01

High-resolution magic angle spinning (HRMAS) (1)H NMR spectroscopy is ideal for monitoring the metabolic environment within tissues, particularly when spectra are weighted by physical properties such as T(1) and T(2) relaxation times and apparent diffusion coefficients (ADCs). In this study, spectral-editing using T(1) and T(2) relaxation times and ADCs at variable diffusion times was used in conjunction with HRMAS (1)H NMR spectroscopy at 14.1 T in liver tissue. To enhance the sensitivity of ADC measurements to low molecular weight metabolites a T(2) spin echo was included in a standard stimulated gradient spin-echo sequence. Fatty liver induced in rats by chronic orotic acid feeding was investigated using this modified sequence. An increase in the combined ADC for the co-resonant peaks glucose, betaine, and TMAO during fatty liver disease was detected (ADCs = 0.60 +/- 0.11 and 0.35 +/- 0.1 * 10(-9) m(2)s(-1) (n = 3) for rats fed with and without orotic acid), indicative of a reduction in glucose and betaine and an increase in TMAO. Copyright 2003 Wiley-Liss, Inc.

A nuclear magnetic resonance spectrometer concept for hermetically sealed magic angle spinning investigations on highly toxic, radiotoxic, or air sensitive materials.

PubMed

Martel, L; Somers, J; Berkmann, C; Koepp, F; Rothermel, A; Pauvert, O; Selfslag, C; Farnan, I

2013-05-01

A concept to integrate a commercial high-resolution, magic angle spinning nuclear magnetic resonance (MAS-NMR) probe capable of very rapid rotation rates (70 kHz) in a hermetically sealed enclosure for the study of highly radiotoxic materials has been developed and successfully demonstrated. The concept centres on a conventional wide bore (89 mm) solid-state NMR magnet operating with industry standard 54 mm diameter probes designed for narrow bore magnets. Rotor insertion and probe tuning take place within a hermetically enclosed glovebox, which extends into the bore of the magnet, in the space between the probe and the magnet shim system. Oxygen-17 MAS-NMR measurements demonstrate the possibility of obtaining high quality spectra from small sample masses (~10 mg) of highly radiotoxic material and the need for high spinning speeds to improve the spectral resolution when working with actinides. The large paramagnetic susceptibility arising from actinide paramagnetism in (Th(1-x)U(x))O2 solid solutions gives rise to extensive spinning sidebands and poor resolution at 15 kHz, which is dramatically improved at 55 kHz. The first (17)O MAS-NMR measurements on NpO(2+x) samples spinning at 55 kHz are also reported. The glovebox approach developed here for radiotoxic materials can be easily adapted to work with other hazardous or even air sensitive materials.

Discrete magic angle turning system, apparatus, and process for in situ magnetic resonance spectroscopy and imaging

DOEpatents

Hu, Jian Zhi [Richland, WA; Sears, Jr., Jesse A.; Hoyt, David W [Richland, WA; Wind, Robert A [Kennewick, WA

2009-05-19

Described are a "Discrete Magic Angle Turning" (DMAT) system, devices, and processes that combine advantages of both magic angle turning (MAT) and magic angle hopping (MAH) suitable, e.g., for in situ magnetic resonance spectroscopy and/or imaging. In an exemplary system, device, and process, samples are rotated in a clockwise direction followed by an anticlockwise direction of exactly the same amount. Rotation proceeds through an angle that is typically greater than about 240 degrees but less than or equal to about 360 degrees at constant speed for a time applicable to the evolution dimension. Back and forth rotation can be synchronized and repeated with a special radio frequency (RF) pulse sequence to produce an isotropic-anisotropic shift 2D correlation spectrum. The design permits tubes to be inserted into the sample container without introducing plumbing interferences, further allowing control over such conditions as temperature, pressure, flow conditions, and feed compositions, thus permitting true in-situ investigations to be carried out.

1H MAS NMR (magic-angle spinning nuclear magnetic resonance) techniques for the quantitative determination of hydrogen types in solid catalysts and supports.

PubMed

Kennedy, Gordon J; Afeworki, Mobae; Calabro, David C; Chase, Clarence E; Smiley, Randolph J

2004-06-01

Distinct hydrogen species are present in important inorganic solids such as zeolites, silicoaluminophosphates (SAPOs), mesoporous materials, amorphous silicas, and aluminas. These H species include hydrogens associated with acidic sites such as Al(OH)Si, non-framework aluminum sites, silanols, and surface functionalities. Direct and quantitative methodology to identify, measure, and monitor these hydrogen species are key to monitoring catalyst activity, optimizing synthesis conditions, tracking post-synthesis structural modifications, and in the preparation of novel catalytic materials. Many workers have developed several techniques to address these issues, including 1H MAS NMR (magic-angle spinning nuclear magnetic resonance). 1H MAS NMR offers many potential advantages over other techniques, but care is needed in recognizing experimental limitations and developing sample handling and NMR methodology to obtain quantitatively reliable data. A simplified approach is described that permits vacuum dehydration of multiple samples simultaneously and directly in the MAS rotor without the need for epoxy, flame sealing, or extensive glovebox use. We have found that careful optimization of important NMR conditions, such as magnetic field homogeneity and magic angle setting are necessary to acquire quantitative, high-resolution spectra that accurately measure the concentrations of the different hydrogen species present. Details of this 1H MAS NMR methodology with representative applications to zeolites, SAPOs, M41S, and silicas as a function of synthesis conditions and post-synthesis treatments (i.e., steaming, thermal dehydroxylation, and functionalization) are presented.

Magic-Angle-Spinning NMR Magnet Development: Field Analysis and Prototypes

PubMed Central

Voccio, John; Hahn, Seungyong; Park, Dong Keun; Ling, Jiayin; Kim, Youngjae; Bascuñán, Juan; Iwasa, Yukikazu

2013-01-01

We are currently working on a program to complete a 1.5 T/75 mm RT bore magic-angle-spinning nuclear magnetic resonance magnet. The magic-angle-spinning magnet comprises a z-axis 0.866-T solenoid and an x-axis 1.225-T dipole, each to be wound with NbTi wire and operated at 4.2 K in persistent mode. A combination of the fields creates a 1.5-T field pointed at 54.74 degrees (magic angle) from the rotation (z) axis. In the first year of this 3-year program, we have completed magnetic analysis and design of both coils. Also, using a winding machine of our own design and fabrication, we have wound several prototype dipole coils with NbTi wire. As part of this development, we have repeatedly made successful persistent NbTi-NbTi joints with this multifilamentary NbTi wire. PMID:24058275

Magic-angle spinning NMR of intact bacteriophages: insights into the capsid, DNA and their interface.

PubMed

Abramov, Gili; Morag, Omry; Goldbourt, Amir

2015-04-01

Bacteriophages are viruses that infect bacteria. They are complex macromolecular assemblies, which are composed of multiple protein subunits that protect genomic material and deliver it to specific hosts. Various biophysical techniques have been used to characterize their structure in order to unravel phage morphogenesis. Yet, most bacteriophages are non-crystalline and have very high molecular weights, in the order of tens of MegaDaltons. Therefore, complete atomic-resolution characterization on such systems that encompass both capsid and DNA is scarce. In this perspective article we demonstrate how magic-angle spinning solid-state NMR has and is used to characterize in detail bacteriophage viruses, including filamentous and icosahedral phage. We discuss the process of sample preparation, spectral assignment of both capsid and DNA and the use of chemical shifts and dipolar couplings to probe the capsid-DNA interface, describe capsid structure and dynamics and extract structural differences between viruses. Copyright © 2015 Elsevier Inc. All rights reserved.

Cryogenic sample exchange NMR probe for magic angle spinning dynamic nuclear polarization

PubMed Central

Barnes, Alexander B.; Mak-Jurkauskas, Melody L.; Matsuki, Yoh; Bajaj, Vikram S.; van der Wel, Patrick C. A.; DeRocher, Ronald; Bryant, Jeffrey; Sirigiri, Jagadishwar R.; Temkin, Richard J.; Lugtenburg, Johan; Herzfeld, Judith; Griffin, Robert G.

2009-01-01

We describe a cryogenic sample exchange system that dramatically improves the efficiency of magic angle spinning (MAS) dynamic nuclear polarization (DNP) experiments by reducing the time required to change samples and by improving long-term instrument stability. Changing samples in conventional cryogenic MAS DNP/NMR experiments involves warming the probe to room temperature, detaching all cryogenic, RF, and microwave connections, removing the probe from the magnet, replacing the sample, and reversing all the previous steps, with the entire cycle requiring a few hours. The sample exchange system described here — which relies on an eject pipe attached to the front of the MAS stator and a vacuum jacketed dewar with a bellowed hole — circumvents these procedures. To demonstrate the excellent sensitivity, resolution, and stability achieved with this quadruple resonance sample exchange probe, we have performed high precision distance measurements on the active site of the membrane protein bacteriorhodopsin. We also include a spectrum of the tripeptide N-f-MLF-OH at 100 K which shows 30 Hz linewidths. PMID:19356957

Spinning angle optical calibration apparatus

DOEpatents

Beer, Stephen K.; Pratt, II, Harold R.

1991-01-01

An optical calibration apparatus is provided for calibrating and reproducing spinning angles in cross-polarization, nuclear magnetic resonance spectroscopy. An illuminated magnifying apparatus enables optical setting an accurate reproducing of spinning "magic angles" in cross-polarization, nuclear magnetic resonance spectroscopy experiments. A reference mark scribed on an edge of a spinning angle test sample holder is illuminated by a light source and viewed through a magnifying scope. When the "magic angle" of a sample material used as a standard is attained by varying the angular position of the sample holder, the coordinate position of the reference mark relative to a graduation or graduations on a reticle in the magnifying scope is noted. Thereafter, the spinning "magic angle" of a test material having similar nuclear properties to the standard is attained by returning the sample holder back to the originally noted coordinate position.

Magnetic resonance metabolomics of intact tissue: a biotechnological tool in cancer diagnostics and treatment evaluation.

PubMed

Bathen, Tone F; Sitter, Beathe; Sjøbakk, Torill E; Tessem, May-Britt; Gribbestad, Ingrid S

2010-09-01

Personalized medicine is increasingly important in cancer treatment for its role in staging and its potential to improve stratification of patients. Different types of molecules, genes, proteins, and metabolites are being extensively explored as potential biomarkers. This review discusses the major findings and potential of tissue metabolites determined by high-resolution magic angle spinning magnetic resonance spectroscopy for cancer detection, characterization, and treatment monitoring.

Solid-state NMR adiabatic TOBSY sequences provide enhanced sensitivity for multidimensional high-resolution magic-angle-spinning 1H MR spectroscopy

NASA Astrophysics Data System (ADS)

Andronesi, Ovidiu C.; Mintzopoulos, Dionyssios; Struppe, Jochem; Black, Peter M.; Tzika, A. Aria

2008-08-01

We propose a solid-state NMR method that maximizes the advantages of high-resolution magic-angle-spinning (HRMAS) applied to intact biopsies when compared to more conventional liquid-state NMR approaches. Theoretical treatment, numerical simulations and experimental results on intact human brain biopsies are presented. Experimentally, it is proven that an optimized adiabatic TOBSY (TOtal through Bond correlation SpectroscopY) solid-state NMR pulse sequence for two-dimensional 1H- 1H homonuclear scalar-coupling longitudinal isotropic mixing provides a 20%-50% improvement in signal-to-noise ratio relative to its liquid-state analogue TOCSY (TOtal Correlation SpectroscopY). For this purpose we have refined the C9151 symmetry-based 13C TOBSY pulse sequence for 1H MRS use and compared it to MLEV-16 TOCSY sequence. Both sequences were rotor-synchronized and implemented using WURST-8 adiabatic inversion pulses. As discussed theoretically and shown in simulations, the improved magnetization-transfer comes from actively removing residual dipolar couplings from the average Hamiltonian. Importantly, the solid-state NMR techniques are tailored to perform measurements at low temperatures where sample degradation is reduced. This is the first demonstration of such a concept for HRMAS metabolic profiling of disease processes, including cancer, from biopsies requiring reduced sample degradation for further genomic analysis.

High-Resolution Magic-Angle-Spinning NMR and Magnetic Resonance Imaging Spectroscopies Distinguish Metabolome and Structural Properties of Maize Seeds from Plants Treated with Different Fertilizers and Arbuscular mycorrhizal fungi.

PubMed

Mazzei, Pierluigi; Cozzolino, Vincenza; Piccolo, Alessandro

2018-03-21

Both high-resolution magic-angle-spinning (HRMAS) and magnetic resonance imaging (MRI) NMR spectroscopies were applied here to identify the changes of metabolome, morphology, and structural properties induced in seeds (caryopses) of maize plants grown at field level under either mineral or compost fertilization in combination with the inoculation by arbuscular mycorrhizal fungi (AMF). The metabolome of intact caryopses was examined by HRMAS-NMR, while the morphological aspects, endosperm properties and seed water distribution were investigated by MRI. Principal component analysis (PCA) was applied to evaluate 1 H CPMG (Carr-Purcel-Meiboom-Gill) HRMAS spectra as well as several MRI-derived parameters ( T 1 , T 2 , and self-diffusion coefficients) of intact maize caryopses. PCA score-plots from spectral results indicated that both seeds metabolome and structural properties depended on the specific field treatment undergone by maize plants. Our findings show that a combination of multivariate statistical analyses with advanced and nondestructive NMR techniques, such as HRMAS and MRI, enables the evaluation of the effects induced on maize caryopses by different fertilization and management practices at field level. The spectroscopic approach adopted here may become useful for the objective appraisal of the quality of seeds produced under a sustainable agriculture.

The effects of high concentrations of ionic liquid on GB1 protein structure and dynamics probed by high-resolution magic-angle-spinning NMR spectroscopy.

PubMed

Warner, Lisa; Gjersing, Erica; Follett, Shelby E; Elliott, K Wade; Dzyuba, Sergei V; Varga, Krisztina

2016-12-01

Ionic liquids have great potential in biological applications and biocatalysis, as some ionic liquids can stabilize proteins and enhance enzyme activity, while others have the opposite effect. However, on the molecular level, probing ionic liquid interactions with proteins, especially in solutions containing high concentration of ionic liquids, has been challenging. In the present work the 13 C, 15 N-enriched GB1 model protein was used to demonstrate applicability of high-resolution magic-angle-spinning (HR-MAS) NMR spectroscopy to investigate ionic liquid - protein interactions. Effect of an ionic liquid (1-butyl-3-methylimidazolium bromide, [C 4 -mim]Br) on GB1was studied over a wide range of the ionic liquid concentrations (0.6 to 3.5 M, which corresponds to 10%-60% v/v). Interactions between GB1 and [C 4 -mim]Br were observed from changes in the chemical shifts of the protein backbone as well as the changes in 15 N ps-ns dynamics and rotational correlation times. Site-specific interactions between the protein and [C 4 -mim]Br were assigned using 3D methods under HR-MAS conditions. Thus, HR-MAS NMR is a viable tool that could aid in elucidation of the molecular mechanism of ionic liquid - protein interactions.

Multidimensional High-Resolution Magic Angle Spinning and Solution-State NMR Characterization of 13C-labeled Plant Metabolites and Lignocellulose

PubMed Central

Mori, Tetsuya; Tsuboi, Yuuri; Ishida, Nobuhiro; Nishikubo, Nobuyuki; Demura, Taku; Kikuchi, Jun

2015-01-01

Lignocellulose, which includes mainly cellulose, hemicellulose, and lignin, is a potential resource for the production of chemicals and for other applications. For effective production of materials derived from biomass, it is important to characterize the metabolites and polymeric components of the biomass. Nuclear magnetic resonance (NMR) spectroscopy has been used to identify biomass components; however, the NMR spectra of metabolites and lignocellulose components are ambiguously assigned in many cases due to overlapping chemical shift peaks. Using our 13C-labeling technique in higher plants such as poplar samples, we demonstrated that overlapping peaks could be resolved by three-dimensional NMR experiments to more accurately assign chemical shifts compared with two-dimensional NMR measurements. Metabolites of the 13C-poplar were measured by high-resolution magic angle spinning NMR spectroscopy, which allows sample analysis without solvent extraction, while lignocellulose components of the 13C-poplar dissolved in dimethylsulfoxide/pyridine solvent were analyzed by solution-state NMR techniques. Using these methods, we were able to unambiguously assign chemical shifts of small and macromolecular components in 13C-poplar samples. Furthermore, using samples of less than 5 mg, we could differentiate between two kinds of genes that were overexpressed in poplar samples, which produced clearly modified plant cell wall components. PMID:26143886

Development and application of high-resolution solid- state NMR dipolar recovery techniques for spin-1/2 nuclei

NASA Astrophysics Data System (ADS)

Joers, James M.

The use of magic angle spinning to obtain high resolution solid state spectra has been well documented. This resolution occurs by coherently averaging the chemical shift anisotropy and dipolar interactions to zero over the period of a full rotation. While this allows for higher resolution, the structural information is seemingly lost to the spectrometer eye. Thus, high resolution spectra and structural information appear to be mutually exlusive. Recently, the push in solid state NMR is the development of recoupling techniques which afford both high resolution and structural information. The following dissertation demonstrates the feasibility of implementing such experiments in solving real world problems, and is centered on devising a method to recover homonuclear dipolar interactions in the high resolution regime.

Spinning angle optical calibration apparatus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beer, S.K.; Pratt, H.R. II.

1989-09-12

An optical calibration apparatus is provided for calibrating and reproducing spinning angles in cross-polarization, nuclear magnetic resonance spectroscopy. An illuminated magnifying apparatus enables optical setting and accurate reproducing of spinning magic angles in cross-polarization, nuclear magnetic resonance spectroscopy experiments. A reference mark scribed on an edge of a spinning angle test sample holder is illuminated by a light source and viewed through a magnifying scope. When the magic angle of a sample material used as a standard is attained by varying the angular position of the sample holder, the coordinate position of the reference mark relative to a graduation ormore » graduations on a reticle in the magnifying scope is noted. Thereafter, the spinning magic angle of a test material having similar nuclear properties to the standard is attained by returning the sample holder back to the originally noted coordinate position. 2 figs.« less

Devices and process for high-pressure magic angle spinning nuclear magnetic resonance

DOEpatents

Hoyt, David W; Sears, Jr., Jesse A; Turcu, Romulus V.F.; Rosso, Kevin M; Hu, Jian Zhi

2014-04-08

A high-pressure magic angle spinning (MAS) rotor is detailed that includes a high-pressure sample cell that maintains high pressures exceeding 150 bar. The sample cell design minimizes pressure losses due to penetration over an extended period of time.

Devices and process for high-pressure magic angle spinning nuclear magnetic resonance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoyt, David W.; Sears, Jesse A.; Turcu, Romulus V. F.

A high-pressure magic angle spinning (MAS) rotor is detailed that includes a high-pressure sample cell that maintains high pressures exceeding 150 bar. The sample cell design minimizes pressure losses due to penetration over an extended period of time.

Nuclear Magnetic Resonance Spectroscopy Applications: Proton NMR In Biological Objects Subjected To Magic Angle Spinning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wind, Robert A.; Hu, Jian Zhi

2005-01-01

Proton NMR in Biological Objects Submitted to Magic Angle Spinning, In Encyclopedia of Analytical Science, Second Edition (Paul J. Worsfold, Alan Townshend and Colin F. Poole, eds.), Elsevier, Oxford 6:333-342. Published January 1, 2005. Proposal Number 10896.

Indirect detection of infinite-speed MAS solid-state NMR spectra

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perras, Frédéric A.; Venkatesh, Amrit; Hanrahan, Michael P.

Heavy spin-1/2 nuclides are known to possess very large chemical shift anisotropies that can challenge even the most advanced magic-angle-spinning (MAS) techniques. Wide manifolds of overlapping spinning sidebands and insufficient excitation bandwidths often obfuscate meaningful spectral information and force the use of static, low-resolution solid-state (SS)NMR methods for the characterization of materials. In order to address these issues, we have merged fast-magic-angle-turning (MAT) and dipolar heteronuclear multiple-quantum coherence (D-HMQC) experiments to obtain D-HMQC-MAT pulse sequences which enable the rapid acquisition of 2D SSNMR spectra that correlate isotropic 1H chemical shifts to the indirectly detected isotropic “infinite-MAS” spectra of heavy spin-1/2more » nuclides. Furthermore, for these nuclides, the combination of fast MAS and 1H detection provides a high sensitivity, which rivals the DNP-enhanced ultra-wideline SSNMR. The new pulse sequences were used to determine the Pt coordination environments in a complex mixture of decomposition products of transplatin and in a metal-organic framework with Pt ions coordinated to the linker ligands.« less

Indirect detection of infinite-speed MAS solid-state NMR spectra

DOE PAGES

Perras, Frédéric A.; Venkatesh, Amrit; Hanrahan, Michael P.; ...

2017-01-18

Heavy spin-1/2 nuclides are known to possess very large chemical shift anisotropies that can challenge even the most advanced magic-angle-spinning (MAS) techniques. Wide manifolds of overlapping spinning sidebands and insufficient excitation bandwidths often obfuscate meaningful spectral information and force the use of static, low-resolution solid-state (SS)NMR methods for the characterization of materials. In order to address these issues, we have merged fast-magic-angle-turning (MAT) and dipolar heteronuclear multiple-quantum coherence (D-HMQC) experiments to obtain D-HMQC-MAT pulse sequences which enable the rapid acquisition of 2D SSNMR spectra that correlate isotropic 1H chemical shifts to the indirectly detected isotropic “infinite-MAS” spectra of heavy spin-1/2more » nuclides. Furthermore, for these nuclides, the combination of fast MAS and 1H detection provides a high sensitivity, which rivals the DNP-enhanced ultra-wideline SSNMR. The new pulse sequences were used to determine the Pt coordination environments in a complex mixture of decomposition products of transplatin and in a metal-organic framework with Pt ions coordinated to the linker ligands.« less

Indirect detection of infinite-speed MAS solid-state NMR spectra

NASA Astrophysics Data System (ADS)

Perras, Frédéric A.; Venkatesh, Amrit; Hanrahan, Michael P.; Goh, Tian Wei; Huang, Wenyu; Rossini, Aaron J.; Pruski, Marek

2017-03-01

Heavy spin-1/2 nuclides are known to possess very large chemical shift anisotropies that can challenge even the most advanced magic-angle-spinning (MAS) techniques. Wide manifolds of overlapping spinning sidebands and insufficient excitation bandwidths often obfuscate meaningful spectral information and force the use of static, low-resolution solid-state (SS)NMR methods for the characterization of materials. To address these issues, we have merged fast-magic-angle-turning (MAT) and dipolar heteronuclear multiple-quantum coherence (D-HMQC) experiments to obtain D-HMQC-MAT pulse sequences which enable the rapid acquisition of 2D SSNMR spectra that correlate isotropic 1H chemical shifts to the indirectly detected isotropic "infinite-MAS" spectra of heavy spin-1/2 nuclides. For these nuclides, the combination of fast MAS and 1H detection provides a high sensitivity, which rivals the DNP-enhanced ultra-wideline SSNMR. The new pulse sequences were used to determine the Pt coordination environments in a complex mixture of decomposition products of transplatin and in a metal-organic framework with Pt ions coordinated to the linker ligands.

Characterization of metabolic profile of intact non-tumor and tumor breast cells by high-resolution magic angle spinning nuclear magnetic resonance spectroscopy.

PubMed

Maria, Roberta M; Altei, Wanessa F; Andricopulo, Adriano D; Becceneri, Amanda B; Cominetti, Márcia R; Venâncio, Tiago; Colnago, Luiz A

2015-11-01

(1)H high-resolution magic angle spinning nuclear magnetic resonance ((1)H HR-MAS NMR) spectroscopy was used to analyze the metabolic profile of an intact non-tumor breast cell line (MCF-10A) and intact breast tumor cell lines (MCF-7 and MDA-MB-231). In the spectra of MCF-10A cells, six metabolites were assigned, with glucose and ethanol in higher concentrations. Fifteen metabolites were assigned in MCF-7 and MDA-MB-231 (1)H HR-MAS NMR spectra. They did not show glucose and ethanol, and the major component in both tumor cells was phosphocholine (higher in MDA-MB-231 than in MCF-7), which can be considered as a tumor biomarker of breast cancer malignant transformation. These tumor cells also show acetone signal that was higher in MDA-MB-231 cells than in MCF-7 cells. The high acetone level may be an indication of high demand for energy in MDA-MB-231 to maintain cell proliferation. The higher acetone and phosphocholine levels in MDA-MB-231 cells indicate the higher malignance of the cell line. Therefore, HR-MAS is a rapid reproducible method to study the metabolic profile of intact breast cells, with minimal sample preparation and contamination, which are critical in the analyses of slow-growth cells. Copyright © 2015 Elsevier Inc. All rights reserved.

The effects of high concentrations of ionic liquid on GB1 protein structure and dynamics probed by high-resolution magic-angle-spinning NMR spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warner, Lisa; Gjersing, Erica; Follett, Shelby E.

Ionic liquids have great potential in biological applications and biocatalysis, as some ionic liquids can stabilize proteins and enhance enzyme activity, while others have the opposite effect. However, on the molecular level, probing ionic liquid interactions with proteins, especially in solutions containing high concentrations of ionic liquids, has been challenging. In the present work the 13C, 15N-enriched GB1 model protein was used to demonstrate applicability of high-resolution magic-angle-spinning (HR-MAS) NMR spectroscopy to investigate ionic liquid-protein interactions. Effect of an ionic liquid (1-butyl-3-methylimidazolium bromide, [C 4-mim]Br) on GB1was studied over a wide range of the ionic liquid concentrations (0.6-3.5 M, whichmore » corresponds to 10-60% v/v). Interactions between GB1 and [C 4-mim]Br were observed from changes in the chemical shifts of the protein backbone as well as the changes in 15N ps-ns dynamics and rotational correlation times. Site-specific interactions between the protein and [C 4-mim]Br were assigned using 3D methods under HR-MAS conditions. Furthermore, HR-MAS NMR is a viable tool that could aid in elucidation of molecular mechanisms of ionic liquid-protein interactions.« less

The effects of high concentrations of ionic liquid on GB1 protein structure and dynamics probed by high-resolution magic-angle-spinning NMR spectroscopy

DOE PAGES

Warner, Lisa; Gjersing, Erica; Follett, Shelby E.; ...

2016-08-11

Ionic liquids have great potential in biological applications and biocatalysis, as some ionic liquids can stabilize proteins and enhance enzyme activity, while others have the opposite effect. However, on the molecular level, probing ionic liquid interactions with proteins, especially in solutions containing high concentrations of ionic liquids, has been challenging. In the present work the 13C, 15N-enriched GB1 model protein was used to demonstrate applicability of high-resolution magic-angle-spinning (HR-MAS) NMR spectroscopy to investigate ionic liquid-protein interactions. Effect of an ionic liquid (1-butyl-3-methylimidazolium bromide, [C 4-mim]Br) on GB1was studied over a wide range of the ionic liquid concentrations (0.6-3.5 M, whichmore » corresponds to 10-60% v/v). Interactions between GB1 and [C 4-mim]Br were observed from changes in the chemical shifts of the protein backbone as well as the changes in 15N ps-ns dynamics and rotational correlation times. Site-specific interactions between the protein and [C 4-mim]Br were assigned using 3D methods under HR-MAS conditions. Furthermore, HR-MAS NMR is a viable tool that could aid in elucidation of molecular mechanisms of ionic liquid-protein interactions.« less

A highly ordered mesostructured material containing regularly distributed phenols: preparation and characterization at a molecular level through ultra-fast magic angle spinning proton NMR spectroscopy.

PubMed

Roussey, Arthur; Gajan, David; Maishal, Tarun K; Mukerjee, Anhurada; Veyre, Laurent; Lesage, Anne; Emsley, Lyndon; Copéret, Christophe; Thieuleux, Chloé

2011-03-14

Highly ordered organic-inorganic mesostructured material containing regularly distributed phenols is synthesized by combining a direct synthesis of the functional material and a protection-deprotection strategy and characterized at a molecular level through ultra-fast magic angle spinning proton NMR spectroscopy.

Double-quantum homonuclear rotary resonance: Efficient dipolar recovery in magic-angle spinning nuclear magnetic resonance

NASA Astrophysics Data System (ADS)

Nielsen, N. C.; Bildsøe, H.; Jakobsen, H. J.; Levitt, M. H.

1994-08-01

We describe an efficient method for the recovery of homonuclear dipole-dipole interactions in magic-angle spinning NMR. Double-quantum homonuclear rotary resonance (2Q-HORROR) is established by fulfilling the condition ωr=2ω1, where ωr is the sample rotation frequency and ω1 is the nutation frequency around an applied resonant radio frequency (rf) field. This resonance can be used for double-quantum filtering and measurement of homonuclear dipolar interactions in the presence of magic-angle spinning. The spin dynamics depend only weakly on crystallite orientation allowing good performance for powder samples. Chemical shift effects are suppressed to zeroth order. The method is demonstrated for singly and doubly 13C labeled L-alanine.

High Resolution Magic Angle Spinning Nuclear Magnetic Resonance (HRMAS NMR) for Studies of Reactive Fabrics

DTIC Science & Technology

2015-11-01

Group Chemistry, 2010, 9, 205-219. 6 C. A. S. Brevett and K. B. Sumpter, “ Sulfur Mustard Degradation on Ambient and Moist Concrete ”, ECBC Technical...reactions of reagents including chemical weapons on materials like concrete , soil, and sand, as well as reactive polymers.3,4,5,6,7 There are...Sumpter, G. W. Wagner, “Degradation of Mustard on Concrete : GC/MSD and SSMAS,” ECBC Technical Report ECBC-TR-482, Edgewood Chemical Biological Center

Sealed magic angle spinning nuclear magnetic resonance probe and process for spectroscopy of hazardous samples

DOEpatents

Cho, Herman M.; Washton, Nancy M.; Mueller, Karl T.; Sears, Jr., Jesse A.; Townsend, Mark R.; Ewing, James R.

2016-06-14

A magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) probe is described that includes double containment enclosures configured to seal and contain hazardous samples for analysis. The probe is of a modular design that ensures containment of hazardous samples during sample analysis while preserving spin speeds for superior NMR performance and convenience of operation.

NMR system and method having a permanent magnet providing a rotating magnetic field

DOEpatents

Schlueter, Ross D [Berkeley, CA; Budinger, Thomas F [Berkeley, CA

2009-05-19

Disclosed herein are systems and methods for generating a rotating magnetic field. The rotating magnetic field can be used to obtain rotating-field NMR spectra, such as magic angle spinning spectra, without having to physically rotate the sample. This result allows magic angle spinning NMR to be conducted on biological samples such as live animals, including humans.

Investigation of Regional Influence of Magic-Angle Effect on T2 in Human Articular Cartilage with Osteoarthritis at 3 T

PubMed Central

Wang, Ligong; Regatte, Ravinder R.

2014-01-01

Rationale and Objectives The objectives of this research study were to determine the magic-angle effect on different subregions of in vivo human femoral cartilage through the quantitative assessment of the effect of static magnetic field orientation (B0) on transverse (T2) relaxation time at 3.0 T. Materials and Methods Healthy volunteers (n = 5l; mean age, 36.4 years) and clinical patients (n = 5; mean age, 64 years) with early osteoarthritis (OA) were scanned at 3.0-T magnetic resonance using an 8-channel phased-array knee coil (transmit-receive). Results The T2 maps revealed significantly greater values in ventral than in dorsal regions. When the cartilage regions were oriented at 55° to B0 (magic angle), the longest T2 values were detected in comparison with the neighboring regions oriented 90° and 180° (0°) to B0. The subregions oriented 180° (0°) to B0 showed the lowest T2 values. Conclusions The differences in T2 values of different subregions suggest that magic-angle effect needs to be considered when interpreting cartilage abnormalities in OA patients. PMID:25481517

Grade classification of neuroepithelial tumors using high-resolution magic-angle spinning proton nuclear magnetic resonance spectroscopy and pattern recognition.

PubMed

Chen, WenXue; Lou, HaiYan; Zhang, HongPing; Nie, Xiu; Lan, WenXian; Yang, YongXia; Xiang, Yun; Qi, JianPin; Lei, Hao; Tang, HuiRu; Chen, FenEr; Deng, Feng

2011-07-01

Clinical data have shown that survival rates vary considerably among brain tumor patients, according to the type and grade of the tumor. Metabolite profiles of intact tumor tissues measured with high-resolution magic-angle spinning proton nuclear magnetic resonance spectroscopy (HRMAS (1)H NMRS) can provide important information on tumor biology and metabolism. These metabolic fingerprints can then be used for tumor classification and grading, with great potential value for tumor diagnosis. We studied the metabolic characteristics of 30 neuroepithelial tumor biopsies, including two astrocytomas (grade I), 12 astrocytomas (grade II), eight anaplastic astrocytomas (grade III), three glioblastomas (grade IV) and five medulloblastomas (grade IV) from 30 patients using HRMAS (1)H NMRS. The results were correlated with pathological features using multivariate data analysis, including principal component analysis (PCA). There were significant differences in the levels of N-acetyl-aspartate (NAA), creatine, myo-inositol, glycine and lactate between tumors of different grades (P<0.05). There were also significant differences in the ratios of NAA/creatine, lactate/creatine, myo-inositol/creatine, glycine/creatine, scyllo-inositol/creatine and alanine/creatine (P<0.05). A soft independent modeling of class analogy model produced a predictive accuracy of 87% for high-grade (grade III-IV) brain tumors with a sensitivity of 87% and a specificity of 93%. HRMAS (1)H NMR spectroscopy in conjunction with pattern recognition thus provides a potentially useful tool for the rapid and accurate classification of human brain tumor grades.

Metabolic profiling of lung granuloma in Mycobacterium tuberculosis infected guinea pigs: ex vivo 1H magic angle spinning NMR studies.

PubMed

Somashekar, B S; Amin, Anita G; Rithner, Christopher D; Troudt, JoLynn; Basaraba, Randall; Izzo, Angelo; Crick, Dean C; Chatterjee, Delphi

2011-09-02

A crucial and distinctive feature of tuberculosis infection is that Mycobacterium tuberculosis (Mtb) resides in granulomatous lesion at various stages of disease development and necrosis, an aspect that is little understood. We used a novel approach, applying high resolution magic angle spinning nuclear magnetic resonance spectroscopy (HRMAS NMR) directly to infected tissues, allowing us to study the development of tuberculosis granulomas in guinea pigs in an untargeted manner. Significant up-regulation of lactate, alanine, acetate, glutamate, oxidized and the reduced form of glutathione, aspartate, creatine, phosphocholine, glycerophosphocholine, betaine, trimethylamine N-oxide, myo-inositol, scyllo-inositol, and dihydroxyacetone was clearly visualized and was identified as the infection progressed. Concomitantly, phosphatidylcholine was down-regulated. Principal component analysis of NMR data revealed clear group separation between infected and uninfected tissues. These metabolites are suggestive of utilization of alternate energy sources by the infiltrating cells that generate much of the metabolites in the increasingly necrotic and hypoxic developing granuloma through the glycolytic, pentose phosphate, and tricarboxylic acid pathways. The most relevant changes seen are, surprisingly, very similar to metabolic changes seen in cancer during tumor development.

Spinning angle optical calibration apparatus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beer, S.K.; Pratt, H.R.

1991-02-26

This patent describes an optical calibration apparatus provided for calibrating and reproducing spinning angles in cross-polarization, nuclear magnetic resonance spectroscopy. An illuminated magnifying apparatus enables optical setting an accurate reproducing of spinning magic angles in cross-polarization, nuclear magnetic resonance spectroscopy experiments. A reference mark scribed on an edge of a spinning angle test sample holder is illuminated by a light source and viewed through a magnifying scope. When the magic angle of a sample material used as a standard is attained by varying the angular position of the sample holder, the coordinate position of the reference mark relative to amore » graduation or graduations on a reticle in the magnifying scope is noted.« less

Reactions of CW Agents HD And GD with the Polymer Fabrics PVAM and CHEMCAT 41

DTIC Science & Technology

2015-09-01

analyses of the rates of G agent decomposition were followed by the methods of solids NMR (high resolution magic angle spinning, HR-MAS). A P-31...molecular weight copolymer of 30-35 kDa. The Erkol copolymer forms a pH 12 solution in water and functions as Lewis base when hydrated .6 GD and DFP...Reactions The hydrated PVAm film, containing 20% glycerol, was found to completely deplete and decompose a two-fold excess of DFP vapor (peaks -8 and

Nano-Mole Scale Side-Chain Signal Assignment by 1H-Detected Protein Solid-State NMR by Ultra-Fast Magic-Angle Spinning and Stereo-Array Isotope Labeling

PubMed Central

Nishiyama, Yusuke; Endo, Yuki; Nemoto, Takahiro; Yamauchi, Kazuo; Asakura, Tetsuo; Takeda, Mitsuhiro; Terauchi, Tsutomu; Kainosho, Masatsune; Ishii, Yoshitaka

2015-01-01

We present a general approach in 1H-detected 13C solid-state NMR (SSNMR) for side-chain signal assignments of 10-50 nmol quantities of proteins using a combination of a high magnetic field, ultra-fast magic-angle spinning (MAS) at ~80 kHz, and stereo-array-isotope-labeled (SAIL) proteins [Kainosho M. et al., Nature 440, 52–57, 2006]. First, we demonstrate that 1H indirect detection improves the sensitivity and resolution of 13C SSNMR of SAIL proteins for side-chain assignments in the ultra-fast MAS condition. 1H-detected SSNMR was performed for micro-crystalline ubiquitin (~55 nmol or ~0.5mg) that was SAIL-labeled at seven isoleucine (Ile) residues. Sensitivity was dramatically improved by 1H-detected 2D 1H/13C SSNMR by factors of 5.4-9.7 and 2.1-5.0, respectively, over 13C-detected 2D 1H/13C SSNMR and 1D 13C CPMAS, demonstrating that 2D 1H-detected SSNMR offers not only additional resolution but also sensitivity advantage over 1D 13C detection for the first time. High 1H resolution for the SAIL-labeled side-chain residues offered reasonable resolution even in the 2D data. A 1H-detected 3D 13C/13C/1H experiment on SAIL-ubiquitin provided nearly complete 1H and 13C assignments for seven Ile residues only within ~2.5 h. The results demonstrate the feasibility of side-chain signal assignment in this approach for as little as 10 nmol of a protein sample within ~3 days. The approach is likely applicable to a variety of proteins of biological interest without any requirements of highly efficient protein expression systems. PMID:25856081

3D Double-Quantum/Double-Quantum Exchange Spectroscopy of Protons under 100 kHz Magic Angle Spinning.

PubMed

Zhang, Rongchun; Duong, Nghia Tuan; Nishiyama, Yusuke; Ramamoorthy, Ayyalusamy

2017-06-22

Solid-state 1 H NMR spectroscopy has attracted much attention in the recent years due to the remarkable spectral resolution improvement by ultrafast magic-angle-spinning (MAS) as well as due to the sensitivity enhancement rendered by proton detection. Although these developments have enabled the investigation of a variety of challenging chemical and biological solids, the proton spectral resolution is still poor for many rigid solid systems owing to the presence of conformational heterogeneity and the unsuppressed residual proton-proton dipolar couplings even with the use of the highest currently feasible sample spinning speed of ∼130 kHz. Although a further increase in the spinning speed of the sample could be beneficial to some extent, there is a need for alternate approaches to enhance the spectral resolution. Herein, by fully utilizing the benefits of double-quantum (DQ) coherences, we propose a single radio frequency channel proton-based 3D pulse sequence that correlates double-quantum (DQ), DQ, and single-quantum (SQ) chemical shifts of protons. In addition to the two-spin homonuclear proximity information, the proposed 3D DQ/DQ/SQ experiment also enables the extraction of three-spin and four-spin proximities, which could be beneficial for revealing the dipolar coupled proton network in the solid state. Besides, the 2D DQ/DQ spectrum sliced at different isotropic SQ chemical shift values of the 3D DQ/DQ/SQ spectrum will also facilitate the identification of DQ correlation peaks and improve the spectral resolution, as it only provides the local homonuclear correlation information associated with the specific protons selected by the SQ chemical shift frequency. The 3D pulse sequence and its efficiency are demonstrated experimentally on small molecular compounds in the solid state. We expect that this approach would create avenues for further developments by suitably combining the benefits of partial deuteration of samples, selective excitation/decoupling pulses, heteronuclear spins for spectral editing, and nonuniform sampling.

Cross-polarization/magic-angle sample-spinning /sup 13/C NMR spectroscopic study of chlorophyll a in the solid state

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, C.E.; Spencer, R.B.; Burger, V.T.

1984-01-01

Solid-state cross-polarization/magic-angle sample-spinning /sup 13/C NMR spectra have been recorded on chlorophyll a-water aggregates, methyl pyrochlorophyllide a, and methyl pyropheophorbide a. Spectra have also been collected under a decoupling regime in which resonances of certain hydrogen-bearing carbon atoms are suppressed. These observations are used to assign the solid-state spectra. 18 references, 2 figures, 1 table.

Application of High-Resolution Magic-Angle Spinning NMR Spectroscopy to Define the Cell Uptake of MRI Contrast Agents

NASA Astrophysics Data System (ADS)

Calabi, Luisella; Alfieri, Goffredo; Biondi, Luca; De Miranda, Mario; Paleari, Lino; Ghelli, Stefano

2002-06-01

A new method, based on proton high-resolution magic-angle spinning ( 1H HR-MAS) NMR spectroscopy, has been employed to study the cell uptake of magnetic resonance imaging contrast agents (MRI-CAs). The method was tested on human red blood cells (HRBC) and white blood cells (HWBC) by using three gadolinium complexes, widely used in diagnostics, Gd-BOPTA, Gd-DTPA, and Gd-DOTA, and the analogous complexes obtained by replacing Gd(III) with Dy(III), Nd(III), and Tb(III) (i.e., complexes isostructural to the ones of gadolinium but acting as shift agents). The method is based on the evaluation of the magnetic effects, line broadening, or induced lanthanide shift (LIS) caused by these complexes on NMR signals of intra- and extracellular water. Since magnetic effects are directly linked to permeability, this method is direct. In all the tests, these magnetic effects were detected for the extracellular water signal only, providing a direct proof that these complexes are not able to cross the cell membrane. Line broadening effects (i.e., the use of gadolinium complexes) only allow qualitative evaluations. On the contrary, LIS effects can be measured with high precision and they can be related to the concentration of the paramagnetic species in the cellular compartments. This is possible because the HR-MAS technique provides the complete elimination of bulk magnetic susceptibility (BMS) shift and the differentiation of extra- and intracellular water signals. Thus with this method, the rapid quantification of the MRI-CA amount inside and outside the cells is actually feasible.

Staging research of human lung cancer tissues by high-resolution magic angle spinning proton nuclear magnetic resonance spectroscopy (HRMAS 1 H NMR) and multivariate data analysis.

PubMed

Chen, Wenxue; Lu, Shaohua; Wang, Guifang; Chen, Fener; Bai, Chunxue

2017-10-01

High-resolution magic-angle spinning proton nuclear magnetic resonance (HRMAS 1 H NMR) spectroscopy technique was employed to analyze the metabonomic characterizations of lung cancer tissues in hope to identify potential diagnostic biomarkers for malignancy detection and staging research of lung tissues. HRMAS 1 H NMR spectroscopy technique can rapidly provide important information for accurate diagnosis and staging of cancer tissues owing to its noninvasive nature and limited requirement for the samples, and thus has been acknowledged as an excellent tool to investigate tissue metabolism and provide a more realistic insight into the metabonomics of tissues when combined with multivariate data analysis (MVDA) such as component analysis and orthogonal partial least squares-discriminant analysis in particular. HRMAS 1 H NMR spectra displayed the metabonomic differences of 32 lung cancer tissues at the different stages from 32 patients. The significant changes (P < 0.05) of some important metabolites such as lipids, aspartate and choline-containing compounds in cancer tissues at the different stages had been identified. Furthermore, the combination of HRMAS 1 H NMR spectroscopy and MVDA might potentially and precisely provided for a high sensitivity, specificity, prediction accuracy in the positive identification of the staging for the cancer tissues in contrast with the pathological data in clinic. This study highlighted the potential of metabonomics in clinical settings so that the techniques might be further exploited for the diagnosis and staging prediction of lung cancer in future. © 2016 John Wiley & Sons Australia, Ltd.

Selective excitation enables assignment of proton resonances and (1)H-(1)H distance measurement in ultrafast magic angle spinning solid state NMR spectroscopy.

PubMed

Zhang, Rongchun; Ramamoorthy, Ayyalusamy

2015-07-21

Remarkable developments in ultrafast magic angle spinning (MAS) solid-state NMR spectroscopy enabled proton-based high-resolution multidimensional experiments on solids. To fully utilize the benefits rendered by proton-based ultrafast MAS experiments, assignment of (1)H resonances becomes absolutely necessary. Herein, we propose an approach to identify different proton peaks by using dipolar-coupled heteronuclei such as (13)C or (15)N. In this method, after the initial preparation of proton magnetization and cross-polarization to (13)C nuclei, transverse magnetization of desired (13)C nuclei is selectively prepared by using DANTE (Delays Alternating with Nutations for Tailored Excitation) sequence and then, it is transferred to bonded protons with a short-contact-time cross polarization. Our experimental results demonstrate that protons bonded to specific (13)C atoms can be identified and overlapping proton peaks can also be assigned. In contrast to the regular 2D HETCOR experiment, only a few 1D experiments are required for the complete assignment of peaks in the proton spectrum. Furthermore, the finite-pulse radio frequency driven recoupling sequence could be incorporated right after the selection of specific proton signals to monitor the intensity buildup for other proton signals. This enables the extraction of (1)H-(1)H distances between different pairs of protons. Therefore, we believe that the proposed method will greatly aid in fast assignment of peaks in proton spectra and will be useful in the development of proton-based multi-dimensional solid-state NMR experiments to study atomic-level resolution structure and dynamics of solids.

The molecular origin of a loading-induced black layer in the deep region of articular cartilage at the magic angle

PubMed Central

Wang, Nian; Kahn, David; Badar, Farid; Xia, Yang

2014-01-01

Purpose To investigate the molecular origin of an unusual low-intensity layer in the deep region of articular cartilage as seen in MRI when the tissue is imaged under compression and oriented at the magic angle. Materials and Methods Microscopic MRI (μMRI) T2 and T1ρ experiments were carried out for both native and degraded (treated with trypsin) 18 specimens. The glycosaminoglycan (GAG) concentrations in the specimens were quantified by both sodium ICP-OES and μMRI Gd(DTPA)2--contrast methods. The mechanical modulus of the specimens was also measured. Results Native tissue shows no load-induced layer, while the trypsin-degraded tissue shows clearly the low-intensity line at the deep part of tissue. The GAG reductions are confirmed by the sodium ICP-OES (from 81.7 ± 5.4 mg/ml to 9.2 ± 3.4 mg/ml), MRI GAG quantification (from 72.4 ± 6.7 mg/ml to 11.2 ± 2.9 mg/ml). The modulus reduction is confirmed by biomechanics (from 4.3 ± 0.7 MPa to 0.3 ± 0.1 MPa). Conclusion Both T2 and T1ρ profiles in native and degraded cartilage show strongly strain-, depth-, and angle-dependent using high resolution MRI. The GAG reduction is responsible for the visualization of a low-intensity layer in deep cartilage when it is loaded and orientated at 55°. PMID:24833266

Field-cycling NMR with high-resolution detection under magic-angle spinning: determination of field-window for nuclear hyperpolarization in a photosynthetic reaction center.

PubMed

Gräsing, Daniel; Bielytskyi, Pavlo; Céspedes-Camacho, Isaac F; Alia, A; Marquardsen, Thorsten; Engelke, Frank; Matysik, Jörg

2017-09-21

Several parameters in NMR depend on the magnetic field strength. Field-cycling NMR is an elegant way to explore the field dependence of these properties. The technique is well developed for solution state and in relaxometry. Here, a shuttle system with magic-angle spinning (MAS) detection is presented to allow for field-dependent studies on solids. The function of this system is demonstrated by exploring the magnetic field dependence of the solid-state photochemically induced nuclear polarization (photo-CIDNP) effect. The effect allows for strong nuclear spin-hyperpolarization in light-induced spin-correlated radical pairs (SCRPs) under solid-state conditions. To this end, 13 C MAS NMR is applied to a photosynthetic reaction center (RC) of the purple bacterium Rhodobacter (R.) sphaeroides wildtype (WT). For induction of the effect in the stray field of the magnet and its subsequent observation at 9.4 T under MAS NMR conditions, the sample is shuttled by the use of an aerodynamically driven sample transfer technique. In the RC, we observe the effect down to 0.25 T allowing to determine the window for the occurrence of the effect to be between about 0.2 and 20 T.

Structural Biology of Supramolecular Assemblies by Magic Angle Spinning NMR Spectroscopy

PubMed Central

Quinn, Caitlin M.; Polenova, Tatyana

2017-01-01

In recent years, exciting developments in instrument technology and experimental methodology have advanced the field of magic angle spinning (MAS) NMR to new heights. Contemporary MAS NMR yields atomic-level insights into structure and dynamics of an astounding range of biological systems, many of which cannot be studied by other methods. With the advent of fast magic angle spinning, proton detection, and novel pulse sequences, large supramolecular assemblies, such as cytoskeletal proteins and intact viruses, are now accessible for detailed analysis. In this review, we will discuss the current MAS NMR methodologies that enable characterization of complex biomolecular systems and will present examples of applications to several classes of assemblies comprising bacterial and mammalian cytoskeleton as well as HIV-1 and bacteriophage viruses. The body of work reviewed herein is representative of the recent advancements in the field, with respect to the complexity of the systems studied, the quality of the data, and the significance to the biology. PMID:28093096

Studies of phospholipid hydration by high-resolution magic-angle spinning nuclear magnetic resonance.

PubMed Central

Zhou, Z; Sayer, B G; Hughes, D W; Stark, R E; Epand, R M

1999-01-01

A sample preparation method using spherical glass ampoules has been used to achieve 1.5-Hz resolution in 1H magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectra of aqueous multilamellar dispersions of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), serving to differentiate between slowly exchanging interlamellar and bulk water and to reveal new molecular-level information about hydration phenomena in these model biological membranes. The average numbers of interlamellar water molecules in multilamellar vesicles (MLVs) of DOPC and POPC were found to be 37.5 +/- 1 and 37.2 +/- 1, respectively, at a spinning speed of 3 kHz. Even at speeds as high as 9 kHz, the number of interlamellar waters remained as high as 31, arguing against dehydration effects for DOPC and POPC. Both homonuclear and heteronuclear nuclear Overhauser enhancement spectroscopy (NOESY and HOESY) were used to establish the location of water near the headgroup of a PC bilayer. 1H NMR comparisons of DOPC with a lipid that can hydrogen bond (monomethyldioleoylphosphatidylethanolamine, MeDOPE) showed the following trends: 1) the interlamellar water resonance was shifted to lower frequency for DOPC but to higher frequency for MeDOPE, 2) the chemical shift variation with temperature for interlamellar water was less than that of bulk water for MeDOPE MLVs, 3) water exchange between the two lipids was rapid on the NMR time scale if they were mixed in the same bilayer, 4) water exchange was slow if they were present in separate MLVs, and 5) exchange between bulk and interlamellar water was found by two-dimensional exchange experiments to be slow, and the exchange rate should be less than 157 Hz. These results illustrate the utility of ultra-high-resolution 1H MAS NMR for determining the nature and extent of lipid hydration as well as the arrangement of nuclei at the membrane/water interface. PMID:9876150

Multiple scattering calculations of relativistic electron energy loss spectra

NASA Astrophysics Data System (ADS)

Jorissen, K.; Rehr, J. J.; Verbeeck, J.

2010-04-01

A generalization of the real-space Green’s-function approach is presented for ab initio calculations of relativistic electron energy loss spectra (EELS) which are particularly important in anisotropic materials. The approach incorporates relativistic effects in terms of the transition tensor within the dipole-selection rule. In particular, the method accounts for relativistic corrections to the magic angle in orientation resolved EELS experiments. The approach is validated by a study of the graphite CK edge, for which we present an accurate magic angle measurement consistent with the predicted value.

Spin-locking and cross-polarization under magic-angle spinning of uniformly labeled solids.

PubMed

Hung, Ivan; Gan, Zhehong

2015-07-01

Spin-locking and cross-polarization under magic-angle spinning are investigated for uniformly (13)C and (15)N labeled solids. In particular, the interferences from chemical shift anisotropy, and (1)H heteronuclear and (13)C homonuclear dipolar couplings are identified. The physical origin of these interferences provides guidelines for selecting the best (13)C and (15)N polarization transfer rf fields. Optimal settings for both the zero- and double-quantum cross-polarization transfer mechanisms are recommended. Copyright © 2015 Elsevier Inc. All rights reserved.

Assessment of a 1H high-resolution magic angle spinning NMR spectroscopy procedure for free sugars quantification in intact plant tissue.

PubMed

Delgado-Goñi, Teresa; Campo, Sonia; Martín-Sitjar, Juana; Cabañas, Miquel E; San Segundo, Blanca; Arús, Carles

2013-08-01

In most plants, sucrose is the primary product of photosynthesis, the transport form of assimilated carbon, and also one of the main factors determining sweetness in fresh fruits. Traditional methods for sugar quantification (mainly sucrose, glucose and fructose) require obtaining crude plant extracts, which sometimes involve substantial sample manipulation, making the process time-consuming and increasing the risk of sample degradation. Here, we describe and validate a fast method to determine sugar content in intact plant tissue by using high-resolution magic angle spinning nuclear magnetic resonance spectroscopy (HR-MAS NMR). The HR-MAS NMR method was used for quantifying sucrose, glucose and fructose in mesocarp tissues from melon fruits (Cucumis melo var. reticulatus and Cucumis melo var. cantalupensis). The resulting sugar content varied among individual melons, ranging from 1.4 to 7.3 g of sucrose, 0.4-2.5 g of glucose; and 0.73-2.83 g of fructose (values per 100 g fw). These values were in agreement with those described in the literature for melon fruit tissue, and no significant differences were found when comparing them with those obtained using the traditional, enzymatic procedure, on melon tissue extracts. The HR-MAS NMR method offers a fast (usually <30 min) and sensitive method for sugar quantification in intact plant tissues, it requires a small amount of tissue (typically 50 mg fw) and avoids the interferences and risks associated with obtaining plant extracts. Furthermore, this method might also allow the quantification of additional metabolites detectable in the plant tissue NMR spectrum.

Selective excitation enables assignment of proton resonances and {sup 1}H-{sup 1}H distance measurement in ultrafast magic angle spinning solid state NMR spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Rongchun; Ramamoorthy, Ayyalusamy, E-mail: ramamoor@umich.edu

2015-07-21

Remarkable developments in ultrafast magic angle spinning (MAS) solid-state NMR spectroscopy enabled proton-based high-resolution multidimensional experiments on solids. To fully utilize the benefits rendered by proton-based ultrafast MAS experiments, assignment of {sup 1}H resonances becomes absolutely necessary. Herein, we propose an approach to identify different proton peaks by using dipolar-coupled heteronuclei such as {sup 13}C or {sup 15}N. In this method, after the initial preparation of proton magnetization and cross-polarization to {sup 13}C nuclei, transverse magnetization of desired {sup 13}C nuclei is selectively prepared by using DANTE (Delays Alternating with Nutations for Tailored Excitation) sequence and then, it is transferredmore » to bonded protons with a short-contact-time cross polarization. Our experimental results demonstrate that protons bonded to specific {sup 13}C atoms can be identified and overlapping proton peaks can also be assigned. In contrast to the regular 2D HETCOR experiment, only a few 1D experiments are required for the complete assignment of peaks in the proton spectrum. Furthermore, the finite-pulse radio frequency driven recoupling sequence could be incorporated right after the selection of specific proton signals to monitor the intensity buildup for other proton signals. This enables the extraction of {sup 1}H-{sup 1}H distances between different pairs of protons. Therefore, we believe that the proposed method will greatly aid in fast assignment of peaks in proton spectra and will be useful in the development of proton-based multi-dimensional solid-state NMR experiments to study atomic-level resolution structure and dynamics of solids.« less

High-Resolution Magic Angle Spinning Nuclear Magnetic Resonance of Intact Zebrafish Embryos Detects Metabolic Changes Following Exposure to Teratogenic Polymethoxyalkenes from Algae

PubMed Central

Roy, Upasana; Jaja-Chimedza, Asha; Sanchez, Kristel; Matysik, Joerg

2016-01-01

Abstract Techniques based on nuclear magnetic resonance (NMR) for imaging and chemical analyses of in vivo, or otherwise intact, biological systems are rapidly emerging and finding diverse applications within a wide range of fields. Very recently, several NMR-based techniques have been developed for the zebrafish as a model animal system. In the current study, the novel application of high-resolution magic angle spinning (HR-MAS) NMR is presented as a means of metabolic profiling of intact zebrafish embryos. Toward investigating the utility of HR-MAS NMR as a toxicological tool, these studies specifically examined metabolic changes of embryos exposed to polymethoxy-1-alkenes (PMAs)—a recently identified family of teratogenic compounds from freshwater algae—as emerging environmental contaminants. One-dimensional and two-dimensional HR-MAS NMR analyses were able to effectively identify and quantify diverse metabolites in early-stage (≤36 h postfertilization) embryos. Subsequent comparison of the metabolic profiles between PMA-exposed and control embryos identified several statistically significant metabolic changes associated with subacute exposure to the teratogen, including (1) elevated inositol as a recognized component of signaling pathways involved in embryo development; (2) increases in several metabolites, including inositol, phosphoryl choline, fatty acids, and cholesterol, which are associated with lipid composition of cell membranes; (3) concomitant increase in glucose and decrease in lactate; and (4) decreases in several biochemically related metabolites associated with central nervous system development and function, including γ-aminobutyric acid, glycine, glutamate, and glutamine. A potentially unifying model/hypothesis of PMA teratogenicity based on the data is presented. These findings, taken together, demonstrate that HR-MAS NMR is a promising tool for metabolic profiling in the zebrafish embryo, including toxicological applications. PMID:27348393

Magic angle for barrier-controlled double quantum dots

NASA Astrophysics Data System (ADS)

Yang, Xu-Chen; Wang, Xin

2018-01-01

We show that the exchange interaction of a singlet-triplet spin qubit confined in double quantum dots, when being controlled by the barrier method, is insensitive to a charged impurity lying along certain directions away from the center of the double-dot system. These directions differ from the polar axis of the double dots by the magic angle, equaling arccos(1 /√{3 })≈54 .7∘ , a value previously found in atomic physics and nuclear magnetic resonance. This phenomenon can be understood from an expansion of the additional Coulomb interaction created by the impurity, but also relies on the fact that the exchange interaction solely depends on the tunnel coupling in the barrier-control scheme. Our results suggest that for a scaled-up qubit array, when all pairs of double dots rotate their respective polar axes from the same reference line by the magic angle, crosstalk between qubits can be eliminated, allowing clean single-qubit operations. While our model is a rather simplified version of actual experiments, our results suggest that it is possible to minimize unwanted couplings by judiciously designing the layout of the qubits.

In-pore exchange and diffusion of carbonate solvent mixtures in nanoporous carbon

DOE PAGES

Alam, Todd M.; Osborn Popp, Thomas M.

2016-06-04

High resolution magic angle spinning (HRMAS) 1H NMR spectroscopy has been used to resolve different surface and in-pore solvent environments of ethylene carbonate (EC) and dimethyl carbonate (DMC) mixtures absorbed within nanoporous carbon (NPC). Two dimensional (2D) 1H HRMAS NMR exchange measurements revealed that the inhomogeneous broadened in-pore resonances have pore-to-pore exchange rates on the millisecond timescale. Pulsed-field gradient (PFG) NMR diffusometry revealed the in-pore self-diffusion constants for both EC and DMC were reduced by up to a factor of five with respect to the diffusion in the non-absorbed solvent mixtures.

Floquet-Magnus expansion for general N-coupled spins systems in magic-angle spinning nuclear magnetic resonance spectra

NASA Astrophysics Data System (ADS)

Mananga, Eugene Stephane; Charpentier, Thibault

2015-04-01

In this paper we present a theoretical perturbative approach for describing the NMR spectrum of strongly dipolar-coupled spin systems under fast magic-angle spinning. Our treatment is based on two approaches: the Floquet approach and the Floquet-Magnus expansion. The Floquet approach is well known in the NMR community as a perturbative approach to get analytical approximations. Numerical procedures are based on step-by-step numerical integration of the corresponding differential equations. The Floquet-Magnus expansion is a perturbative approach of the Floquet theory. Furthermore, we address the " γ -encoding" effect using the Floquet-Magnus expansion approach. We show that the average over " γ " angle can be performed for any Hamiltonian with γ symmetry.

Accurate Molecular Orientation Analysis Using Infrared p-Polarized Multiple-Angle Incidence Resolution Spectrometry (pMAIRS) Considering the Refractive Index of the Thin Film Sample.

PubMed

Shioya, Nobutaka; Shimoaka, Takafumi; Murdey, Richard; Hasegawa, Takeshi

2017-06-01

Infrared (IR) p-polarized multiple-angle incidence resolution spectrometry (pMAIRS) is a powerful tool for analyzing the molecular orientation in an organic thin film. In particular, pMAIRS works powerfully for a thin film with a highly rough surface irrespective of degree of the crystallinity. Recently, the optimal experimental condition has comprehensively been revealed, with which the accuracy of the analytical results has largely been improved. Regardless, some unresolved matters still remain. A structurally isotropic sample, for example, yields different peak intensities in the in-plane and out-of-plane spectra. In the present study, this effect is shown to be due to the refractive index of the sample film and a correction factor has been developed using rigorous theoretical methods. As a result, with the use of the correction factor, organic materials having atypical refractive indices such as perfluoroalkyl compounds ( n = 1.35) and fullerene ( n = 1.83) can be analyzed with high accuracy comparable to a compound having a normal refractive index of approximately 1.55. With this improved technique, we are also ready for discriminating an isotropic structure from an oriented sample having the magic angle of 54.7°.

High-pressure, high-temperature magic angle spinning nuclear magnetic resonance devices and processes for making and using same

DOEpatents

Hu, Jian Zhi; Hu, Mary Y.; Townsend, Mark R.; Lercher, Johannes A.; Peden, Charles H. F.

2015-10-06

Re-usable ceramic magic angle spinning (MAS) NMR rotors constructed of high-mechanic strength ceramics are detailed that include a sample compartment that maintains high pressures up to at least about 200 atmospheres (atm) and high temperatures up to about least about 300.degree. C. during operation. The rotor designs minimize pressure losses stemming from penetration over an extended period of time. The present invention makes possible a variety of in-situ high pressure, high temperature MAS NMR experiments not previously achieved in the prior art.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pilgrim, C. D.; Callahan, J. R.; Colla, C. A.

Here, one-dimensional 27Al, 23Na Magic-Angle-Spinning (MAS) NMR and 27Al Multiple-Quantum Magic-Angle-Spinning NMR (MQMAS) measurements are reported for the δ-isomer of the Al 13 Keggin structure at high spinning speed and 14.1 T field. Values for the CQ and η parameters are on the same scale as those seen in other isomers of the Al 13 structure. Density functional theory (DFT) calculations are performed for comparison to the experimental fits using the B3PW91/6-31+G* and PBE0/6-31+G* levels of theory, with the Polarizable Continuum Model (PCM).

The use of variable temperature and magic-angle sample spinning in studies of fulvic acids

USGS Publications Warehouse

Earl, W.L.; Wershaw, R. L.; Thorn, K.A.

1987-01-01

Intensity distortions and poor signal to noise in the cross-polarization magic-angle sample spinning NMR of fulvic acids were investigated and attributed to molecular mobility in these ostensibly "solid" materials. We have shown that inefficiencies in cross polarization can be overcome by lowering the sample temperature to about -60??C. These difficulties can be generalized to many other synthetic and natural products. The use of variable temperature and cross-polarization intensity as a function of contact time can yield valuable qualitative information which can aid in the characterization of many materials. ?? 1987.

Magic tilt angle for stabilizing two-dimensional solitons by dipole-dipole interactions

NASA Astrophysics Data System (ADS)

Chen, Xing-You; Chuang, You-Lin; Lin, Chun-Yan; Wu, Chien-Ming; Li, Yongyao; Malomed, Boris A.; Lee, Ray-Kuang

2017-10-01

In the framework of the Gross-Pitaevskii equation, we study the formation and stability of effectively two-dimensional solitons in dipolar Bose-Einstein condensates (BECs), with dipole moments polarized at an arbitrary angle θ relative to the direction normal to the system's plane. Using numerical methods and the variational approximation, we demonstrate that unstable Townes solitons, created by the contact attractive interaction, may be completely stabilized (with an anisotropic shape) by the dipole-dipole interaction (DDI), in the interval θcr<θ ≤π /2 . The stability boundary θcr weakly depends on the relative strength of the DDI, remaining close to the magic angle θm=arccos(1 /√{3 }) . The results suggest that DDIs provide a generic mechanism for the creation of stable BEC solitons in higher dimensions.

(14)N overtone transition in double rotation solid-state NMR.

PubMed

Haies, Ibraheem M; Jarvis, James A; Brown, Lynda J; Kuprov, Ilya; Williamson, Philip T F; Carravetta, Marina

2015-10-07

Solid-state NMR transitions involving outer energy levels of the spin-1 (14)N nucleus are immune, to first order in perturbation theory, to the broadening caused by the nuclear quadrupole interaction. The corresponding overtone spectra, when acquired in conjunction with magic-angle sample spinning, result in lines, which are just a few kHz wide, permitting the direct detection of nitrogen compounds without the need for labeling. Despite the success of this technique, "overtone" resonances are still broadened due to indirect, second order effects arising from the large quadrupolar interaction. Here we demonstrate that another order of magnitude in spectral resolution may be gained by using double rotation. This brings the width of the (14)N solid-state NMR lines much closer to the region commonly associated with high-resolution solid-state NMR spectroscopy of (15)N and demonstrates the improvements in resolution that may be possible through the development of pulsed methodologies to suppress these second order effects.

27Al MQMAS of the δ-Al 13-Keggin

DOE PAGES

Pilgrim, C. D.; Callahan, J. R.; Colla, C. A.; ...

2017-01-20

Here, one-dimensional 27Al, 23Na Magic-Angle-Spinning (MAS) NMR and 27Al Multiple-Quantum Magic-Angle-Spinning NMR (MQMAS) measurements are reported for the δ-isomer of the Al 13 Keggin structure at high spinning speed and 14.1 T field. Values for the CQ and η parameters are on the same scale as those seen in other isomers of the Al 13 structure. Density functional theory (DFT) calculations are performed for comparison to the experimental fits using the B3PW91/6-31+G* and PBE0/6-31+G* levels of theory, with the Polarizable Continuum Model (PCM).

Magnetic resonance imaging of DNP enhancements in a rotor spinning at the magic angle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perras, Frederic A.; Kobayashi, Takeshi; Pruski, Marek

Simulations performed on model, static, samples have shown that the microwave power is non-uniformly distributed in the magic angle spinning (MAS) rotor when using conventional dynamic nuclear polarization (DNP) instrumentation. Here, we applied the stray-field magic angle spinning imaging (STRAFI–MAS) experiment to generate a spatial map of the DNP enhancements in a full rotor, which is spun at a low rate in a commercial DNP–MAS NMR system. Notably, we observed that the enhancement factors produced in the center of the rotor can be twice as large as those produced at the top of the rotor. Surprisingly, we observed that themore » largest enhancement factors are observed along the axis of the rotor as opposed to against its walls, which are most directly irradiated by the microwave beam. We lastly observed that the distribution of enhancement factors can be moderately improved by degassing the sample and increasing the microwave power. The inclusion of dielectric particles greatly amplifies the enhancement factors throughout the rotor. Furthermore, the STRAFI–MAS approach can provide useful guidance for optimizing the access of microwave power to the sample, and thereby lead to further increases in sensitivity of DNP–MAS NMR.« less

Magnetic resonance imaging of DNP enhancements in a rotor spinning at the magic angle

DOE PAGES

Perras, Frederic A.; Kobayashi, Takeshi; Pruski, Marek

2016-02-23

Simulations performed on model, static, samples have shown that the microwave power is non-uniformly distributed in the magic angle spinning (MAS) rotor when using conventional dynamic nuclear polarization (DNP) instrumentation. Here, we applied the stray-field magic angle spinning imaging (STRAFI–MAS) experiment to generate a spatial map of the DNP enhancements in a full rotor, which is spun at a low rate in a commercial DNP–MAS NMR system. Notably, we observed that the enhancement factors produced in the center of the rotor can be twice as large as those produced at the top of the rotor. Surprisingly, we observed that themore » largest enhancement factors are observed along the axis of the rotor as opposed to against its walls, which are most directly irradiated by the microwave beam. We lastly observed that the distribution of enhancement factors can be moderately improved by degassing the sample and increasing the microwave power. The inclusion of dielectric particles greatly amplifies the enhancement factors throughout the rotor. Furthermore, the STRAFI–MAS approach can provide useful guidance for optimizing the access of microwave power to the sample, and thereby lead to further increases in sensitivity of DNP–MAS NMR.« less

Directly and indirectly detected through-bond heteronuclear correlation solid-state NMR spectroscopy under fast MAS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mao, Kanmi; Pruski, Marek

Two-dimensional through-bond {sup 1}H({sup 13}C) solid-state NMR experiments utilizing fast magic angle spinning (MAS) and homonuclear multipulse {sup 1}H decoupling are presented. Remarkable efficiency of polarization transfer can be achieved at MAS rates exceeding 40 kHz, which is instrumental in these measurements. Schemes utilizing direct and indirect detection of heteronuclei are compared in terms of resolution and sensitivity. A simple procedure for optimization of {sup 1}H homonuclear decoupling sequences under these conditions is proposed. The capabilities of these techniques were confirmed on two naturally abundant solids, tripeptide N-formyl-l-methionyl-l-leucyl-l-phenylalanine (f-MLF-OH) and brown coal.

Directly and indirectly detected through-bond heteronuclear correlation solid-state NMR spectroscopy under fast MAS

NASA Astrophysics Data System (ADS)

Mao, Kanmi; Pruski, Marek

2009-12-01

Two-dimensional through-bond 1H{ 13C} solid-state NMR experiments utilizing fast magic angle spinning (MAS) and homonuclear multipulse 1H decoupling are presented. Remarkable efficiency of polarization transfer can be achieved at MAS rates exceeding 40 kHz, which is instrumental in these measurements. Schemes utilizing direct and indirect detection of heteronuclei are compared in terms of resolution and sensitivity. A simple procedure for optimization of 1H homonuclear decoupling sequences under these conditions is proposed. The capabilities of these techniques were confirmed on two naturally abundant solids, tripeptide N- formyl- L-methionyl- L-leucyl- L-phenylalanine (f-MLF-OH) and brown coal.

Heterogeneous data fusion for brain tumor classification.

PubMed

Metsis, Vangelis; Huang, Heng; Andronesi, Ovidiu C; Makedon, Fillia; Tzika, Aria

2012-10-01

Current research in biomedical informatics involves analysis of multiple heterogeneous data sets. This includes patient demographics, clinical and pathology data, treatment history, patient outcomes as well as gene expression, DNA sequences and other information sources such as gene ontology. Analysis of these data sets could lead to better disease diagnosis, prognosis, treatment and drug discovery. In this report, we present a novel machine learning framework for brain tumor classification based on heterogeneous data fusion of metabolic and molecular datasets, including state-of-the-art high-resolution magic angle spinning (HRMAS) proton (1H) magnetic resonance spectroscopy and gene transcriptome profiling, obtained from intact brain tumor biopsies. Our experimental results show that our novel framework outperforms any analysis using individual dataset.

Access to aliphatic protons as reporters in non-deuterated proteins by solid-state NMR.

PubMed

Vasa, Suresh Kumar; Rovó, Petra; Giller, Karin; Becker, Stefan; Linser, Rasmus

2016-03-28

Interactions within proteins, with their surrounding, and with other molecules are mediated mostly by hydrogen atoms. In fully protonated, inhomogeneous, or larger proteins, however, aliphatic proton shifts tend to show little dispersion despite fast Magic-Angle Spinning. 3D correlations dispersing aliphatic proton shifts by their better resolved amide N/H shifts can alleviate this problem. Using inverse second-order cross-polarization (iSOCP), we here introduce dedicated and improved means to sensitively link site-specific chemical shift information from aliphatic protons with a backbone amide resolution. Thus, even in cases where protein deuteration is impossible, this approach may enable access to various aspects of protein functions that are reported on by protons.

Structure of Ancient Glass by 29 Si Magic Angle Spinning NMR Spectroscopy.

PubMed

Bradford, Henry; Ryder, Amy; Henderson, Julian; Titman, Jeremy J

2018-05-23

29 Si magic angle spinning (MAS) NMR spectroscopy has been applied for the first time to the structural analysis of ancient glass samples obtained from archaeological excavations. The results show that it is possible to establish the distribution of Si environments in ancient glass by 29 Si MAS NMR, so long as the concentrations of magnetic impurities, such as Mn and Fe oxides, are low. In general, good agreement has been obtained with compositions determined by means of electron probe microanalysis. In addition, the 29 Si MAS NMR data reveal structural differences between glasses manufactured at separate ancient sites. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tunable magic wavelengths for trapping with focused Laguerre-Gaussian beams

NASA Astrophysics Data System (ADS)

Bhowmik, Anal; Dutta, Narendra Nath; Majumder, Sonjoy

2018-02-01

We present in this paper a theory of dynamic polarizability for an atomic state due to an external field of nonparaxial Laguerre-Gaussian (LG) beam using the sum-over-states technique. A highly correlated relativistic coupled-cluster theory is used to evaluate the most important and correlation-sensitive parts of the sum. The theory is applied on Sr+ to determine the magic wavelengths for 5 s1 /2→4 d3 /2,4 d5 /2 transitions. Results show the variation of magic wavelengths with the choice of orbital and spin angular momenta of the incident LG beam. Also, the tunability of the magic wavelengths is studied by using the focusing angle of the LG beam and its efficiency in the near-infrared region is observed. Evaluations of the wide spectrum of magic wavelengths from infrared to ultraviolet have substantial importance to experimentalists for carrying out high-precision measurements in fundamental physics. These magic wavelengths can be used to confine the atom or ion at the dark central node or at the high-intensity ring of the LG beam.

Intratumoral Agreement of High-Resolution Magic Angle Spinning Magnetic Resonance Spectroscopic Profiles in the Metabolic Characterization of Breast Cancer

PubMed Central

Park, Vivian Youngjean; Yoon, Dahye; Koo, Ja Seung; Kim, Eun-Kyung; Kim, Seung Il; Choi, Ji Soo; Park, Seho; Park, Hyung Seok; Kim, Suhkmann; Kim, Min Jung

2016-01-01

Abstract High-resolution magic angle spinning (HR-MAS) magnetic resonance (MR) spectroscopy data may serve as a biomarker for breast cancer, with only a small volume of tissue sample required for assessment. However, previous studies utilized only a single tissue sample from each patient. The aim of this study was to investigate whether intratumoral location and biospecimen type affected the metabolic characterization of breast cancer assessed by HR-MAS MR spectroscopy This prospective study was approved by the institutional review board and informed consent was obtained. Preoperative core-needle biopsies (CNBs), central, and peripheral surgical tumor specimens were prospectively collected under ultrasound (US) guidance in 31 patients with invasive breast cancer. Specimens were assessed with HR-MAS MR spectroscopy. The reliability of metabolite concentrations was evaluated and multivariate analysis was performed according to intratumoral location and biospecimen type. There was a moderate or higher agreement between the relative concentrations of 94.3% (33 of 35) of metabolites in the center and periphery, 80.0% (28 of 35) of metabolites in the CNB and central surgical specimens, and 82.9% (29 of 35) of metabolites between all 3 specimen types. However, there was no significant agreement between the concentrations of phosphocholine (PC) and phosphoethanolamine (PE) in the center and periphery. The concentrations of several metabolites (adipate, arginine, fumarate, glutamate, PC, and PE) had no significant agreement between the CNB and central surgical specimens. In conclusion, most HR-MAS MR spectroscopic data do not differ based on intratumoral location or biospecimen type. However, some metabolites may be affected by specimen-related variables, and caution is recommended in decision-making based solely on metabolite concentrations, particularly PC and PE. Further validation through future studies is needed for the clinical implementation of these biomarkers based on data from a single tissue sample. PMID:27082613

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.

PubMed

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 responses of clam heart tissue to TBT exposure are not dose dependent. Metabolic profile analyses indicated that TBT 10 -6 M, contrary to the two other doses tested, led to a significant depletion of taurine and betaine. Glycine levels decreased in all clam groups treated with the organotin. It is suggested that TBT abolished the cytoprotective effect of taurine, betaine and glycine thereby inducing cardiomyopathie. Moreover, results also showed that TBT induced increase in the level of alanine and succinate suggesting the occurrence of anaerobiosis particularly in clam group exposed to the highest dose of TBT. Taken together, these results demonstrate that TBT is a potential toxin with a variety of deleterious effects on clam and this organotin may affect different pathways depending to the used dose. The main finding of this study was the appearance of an original metabolite after TBT treatment likely N-glycine-N'-alanine. It is the first time that this molecule has been identified as a natural compound. Its exact role is unknown and remains to be elucidated. We suppose that its formation could play an important role in clam defense response by attenuating Ca 2+ dependent cell death induced by TBT. Therefore this compound could be a promising biomarker for TBT exposure.

Methods for magnetic resonance analysis using magic angle technique

DOEpatents

Hu, Jian Zhi [Richland, WA; Wind, Robert A [Kennewick, WA; Minard, Kevin R [Kennewick, WA; Majors, Paul D [Kennewick, WA

2011-11-22

Methods of performing a magnetic resonance analysis of a biological object are disclosed that include 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. In particular embodiments the method includes pulsing the radio frequency to provide at least two of a spatially selective read pulse, a spatially selective phase pulse, and a spatially selective storage pulse. Further disclosed methods provide pulse sequences that provide extended imaging capabilities, such as chemical shift imaging or multiple-voxel data acquisition.

Studies of an Isolated 15N- 15N Spin Pair. Off-Angle Fast-Sample-Spinning NMR and Self-Consistent-Field Calculations for Diazo Systems

NASA Astrophysics Data System (ADS)

Challoner, Robin; Harris, Robin K.; Tossell, John A.

1997-05-01

An off-magic-angle spinning study of the nonassociated molecular solid, doubly15N-labeled 5-methyl-2-diazobenzenesulphonic acid hydrochloride (I) is reported. The validity of the off-magic-angle spinning approach under fast-spinning conditions is verified by average Hamiltonian theory. Ab initio SCF calculations were performed on the simpler molecule, C6H5N2+, to provide the shielding parameters, the dipolar coupling between the two nitrogen nuclei, and the electric field gradient existing at both the α-nitrogen and β-nitrogen sites. The calculated values are in good agreement with the shielding and effective dipolar coupling data elucidated in the present investigation, and with a previous study of the two singly15N-labeled isotopomers in which information concerning the electric field gradient at the α and β sites was deduced.

Polarization and photometric observations of the gamma-ray blazar PG 1553+113

NASA Astrophysics Data System (ADS)

Andruchow, I.; Combi, J. A.; Muñoz-Arjonilla, A. J.; Romero, G. E.; Cellone, S. A.; Martí, J.

2011-07-01

We present the results of an observational photo-polarimetry campaign of the blazar PG 1553+113 at optical wavelengths. The blazar was recently detected at very high energies (>100 GeV) by the HESS and MAGIC γ-ray Cherenkov telescopes. Our high-temporal resolution data show significant variations in the linear polarization percentage and position angle at inter-night time-scales, while at shorter (intra-night) time-scales both parameters varied less significantly, if at all. Changes in the polarization angle seem to be common in γ-ray emitting blazars. Simultaneous differential photometry (through the B and R bands) shows no significant variability in the total optical flux. We provide B and R magnitudes, along with a finding chart, for a set of field stars suitable for differential photometry. Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC).

Magic angle spinning NMR with metallized rotors as cylindrical microwave resonators.

PubMed

Scott, Faith J; Sesti, Erika L; Choi, Eric J; Laut, Alexander J; Sirigiri, Jagadishwar R; Barnes, Alexander B

2018-04-19

We introduce a novel design for millimeter wave electromagnetic structures within magic angle spinning (MAS) rotors. In this demonstration, a copper coating is vacuum deposited onto the outside surface of a sapphire rotor at a thickness of 50 nm. This thickness is sufficient to reflect 197-GHz microwaves, yet not too thick as to interfere with radiofrequency fields at 300 MHz or prevent sample spinning due to eddy currents. Electromagnetic simulations of an idealized rotor geometry show a microwave quality factor of 148. MAS experiments with sample rotation frequencies of ω r /2π = 5.4 kHz demonstrate that the drag force due to eddy currents within the copper does not prevent sample spinning. Spectra of sodium acetate show resolved 13 C J-couplings of 60 Hz and no appreciable broadening between coated and uncoated sapphire rotors, demonstrating that the copper coating does not prevent shimming and high-resolution nuclear magnetic resonance spectroscopy. Additionally, 13 C Rabi nutation curves of ω 1 /2π = 103 kHz for both coated and uncoated rotors indicate no detrimental impact of the copper coating on radio frequency coupling of the nuclear spins to the sample coil. We present this metal coated rotor as a first step towards an MAS resonator. MAS resonators are expected to have a significant impact on developments in electron decoupling, pulsed dynamic nuclear polarization (DNP), room temperature DNP, DNP with low-power microwave sources, and electron paramagnetic resonance detection. Copyright © 2018 John Wiley & Sons, Ltd.

Creativity, Magic and Morality: The Dilemma of the Young Gifted Child.

ERIC Educational Resources Information Center

Buescher, Thomas M.

1979-01-01

The article explores the dilemma of young gifted children (ages 4-8 years) in the evolution and resolution of their own system of morality. The author explains that research and observation has revealed a systematic appearance and disappearance of magical thinking (the hallmark of the onset of reasoning) in four stages. (PHR)

Determination of Structural Topology of a Membrane Protein in Lipid -Bilayers using Polarization Optimized Experiments (POE) for Static and MAS Solid State NMR Spectroscopy

PubMed Central

Mote, Kaustubh R.; Gopinath, T.; Veglia, Gianluigi

2013-01-01

The low sensitivity inherent to both the static and magic angle spinning techniques of solid-state NMR (ssNMR) spectroscopy has thus far limited the routine application of multidimensional experiments to determine the structure of membrane proteins in lipid bilayers. Here, we demonstrate the advantage of using a recently developed class of experiments, polarization optimized experiments (POE), for both static and MAS spectroscopy to achieve higher sensitivity and substantial time-savings for 2D and 3D experiments. We used sarcolipin, a single pass membrane protein, reconstituted in oriented bicelles (for oriented ssNMR) and multilamellar vesicles (for MAS ssNMR) as a benchmark. The restraints derived by these experiments are then combined into a hybrid energy function to allow simultaneous determination of structure and topology. The resulting structural ensemble converged to a helical conformation with a backbone RMSD ∼ 0.44 Å, a tilt angle of 24° ± 1°, and an azimuthal angle of 55° ± 6°. This work represents a crucial first step toward obtaining high-resolution structures of large membrane proteins using combined multidimensional O-ssNMR and MAS-ssNMR. PMID:23963722

Singularities in the lineshape of a second-order perturbed quadrupolar nucleus. The magic-angle spinning case.

PubMed

Field, Timothy R; Bain, Alex D

2014-01-01

For a nucleus with a half-integral spin and a strong quadrupole coupling, the central transition (from magnetic quantum number -1/2 to +1/2) in the spectrum shows a characteristic lineshape. By strong coupling, we mean an interaction strong enough so that second-order perturbation theory is needed, yet still sufficient. The spectrum of a static sample is well-known and the magic-angle-spinning (MAS spectrum) is different, but still can be calculated. The important features of both these spectra are singularities and steps in the lineshape, since these are the main tools in fitting the calculated spectrum to experimental data. A useful tool in this investigation is a plot of the frequency as a function of orientation over the surface of the unit sphere. These plots have maxima, minima and saddle points, and these correspond to the features of the spectrum. We used these plots to define both the positions and derive new formulae for the heights of the features and we now extend this to the magic-angle spinning case. For the first time, we identify the orientations corresponding to the features of the MAS spectra and derive formulae for the heights. We then compare the static and MAS cases and show the relationships between the features in the two spectra. Copyright © 2014 Elsevier Inc. All rights reserved.

Studying Dynamics by Magic-Angle Spinning Solid-State NMR Spectroscopy: Principles and Applications to Biomolecules

PubMed Central

Schanda, Paul; Ernst, Matthias

2016-01-01

Magic-angle spinning solid-state NMR spectroscopy is an important technique to study molecular structure, dynamics and interactions, and is rapidly gaining importance in biomolecular sciences. Here we provide an overview of experimental approaches to study molecular dynamics by MAS solid-state NMR, with an emphasis on the underlying theoretical concepts and differences of MAS solid-state NMR compared to solution-state NMR. The theoretical foundations of nuclear spin relaxation are revisited, focusing on the particularities of spin relaxation in solid samples under magic-angle spinning. We discuss the range of validity of Redfield theory, as well as the inherent multi-exponential behavior of relaxation in solids. Experimental challenges for measuring relaxation parameters in MAS solid-state NMR and a few recently proposed relaxation approaches are discussed, which provide information about time scales and amplitudes of motions ranging from picoseconds to milliseconds. We also discuss the theoretical basis and experimental measurements of anisotropic interactions (chemical-shift anisotropies, dipolar and quadrupolar couplings), which give direct information about the amplitude of motions. The potential of combining relaxation data with such measurements of dynamically-averaged anisotropic interactions is discussed. Although the focus of this review is on the theoretical foundations of dynamics studies rather than their application, we close by discussing a small number of recent dynamics studies, where the dynamic properties of proteins in crystals are compared to those in solution. PMID:27110043

Screening molecular associations with lipid membranes using natural abundance 13C cross-polarization magic-angle spinning NMR and principal component analysis.

PubMed

Middleton, David A; Hughes, Eleri; Madine, Jillian

2004-08-11

We describe an NMR approach for detecting the interactions between phospholipid membranes and proteins, peptides, or small molecules. First, 1H-13C dipolar coupling profiles are obtained from hydrated lipid samples at natural isotope abundance using cross-polarization magic-angle spinning NMR methods. Principal component analysis of dipolar coupling profiles for synthetic lipid membranes in the presence of a range of biologically active additives reveals clusters that relate to different modes of interaction of the additives with the lipid bilayer. Finally, by representing profiles from multiple samples in the form of contour plots, it is possible to reveal statistically significant changes in dipolar couplings, which reflect perturbations in the lipid molecules at the membrane surface or within the hydrophobic interior.

A novel dipolar dephasing method for the slow magic angle turning experiment.

PubMed

Hu, J Z; Taylor, C M; Pugmire, R J; Grant, D M

2001-09-01

Complete suppression of the resonances from protonated carbons in a slow magic angle spinning experiment can be achieved using five dipolar dephasing (Five-DD) periods distributed in one rotor period. This produces a spectrum containing only the spinning sidebands (SSB) from the nonprotonated carbons. It is shown that the SSB patterns corresponding to the nonprotonated carbons are not distorted over a wide range of dipolar dephasing times. Hence, this method can be used to obtain reliable principal values of the chemical shift tensors for each nonprotonated carbon. The Five-DD method can be readily incorporated into isotropic-anisotropic 2D experiments such as FIREMAT and 2D-PASS to facilitate the measurement of the (13)C chemical shift tensors in complex systems. Copyright 2001 Academic Press.

An NMR thermometer for cryogenic magic-angle spinning NMR: The spin-lattice relaxation of 127I in cesium iodide

NASA Astrophysics Data System (ADS)

Sarkar, Riddhiman; Concistrè, Maria; Johannessen, Ole G.; Beckett, Peter; Denning, Mark; Carravetta, Marina; al-Mosawi, Maitham; Beduz, Carlo; Yang, Yifeng; Levitt, Malcolm H.

2011-10-01

The accurate temperature measurement of solid samples under magic-angle spinning (MAS) is difficult in the cryogenic regime. It has been demonstrated by Thurber et al. (J. Magn. Reson., 196 (2009) 84-87) [10] that the temperature dependent spin-lattice relaxation time constant of 79Br in KBr powder can be useful for measuring sample temperature under MAS over a wide temperature range (20-296 K). However the value of T1 exceeds 3 min at temperatures below 20 K, which is inconveniently long. In this communication, we show that the spin-lattice relaxation time constant of 127I in CsI powder can be used to accurately measure sample temperature under MAS within a reasonable experimental time down to 10 K.

Non-Fermi-liquid magic angle effects in high magnetic fields

NASA Astrophysics Data System (ADS)

Lebed, A. G.

2016-07-01

We investigate a theoretical problem of electron-electron interactions in an inclined magnetic field in a quasi-one-dimensional (Q1D) conductor. We show that they result in strong non-Fermi-liquid corrections to a specific heat, provided that the direction of the magnetic field is far from the so-called Lebed's magic angles (LMAs). If magnetic field is directed close to one of the LMAs, the specific heat corrections become small and the Fermi-liquid picture restores. As a result, we predict Fermi-liquid-non-Fermi-liquid angular crossovers in the vicinities of the LMA directions of the field. We suggest to perform the corresponding experiment in the Q1D conductor (Per) 2Au (mnt) 2 under pressure in magnetic fields of the order of H ≃25 T .

Puzzles Pastimes Problems.

ERIC Educational Resources Information Center

Eperson, D. B.

1991-01-01

This section includes eight problems to which the journal invites readers to respond. Problem topics include angles in alternate segments, pentominoes, a new triangle of numbers, cricket scores, symmetrical pentagons, inequalities, a pythagorean dissection, and magic squares. (MDH)

Measurement of 13C chemical shift tensor principal values with a magic-angle turning experiment.

PubMed

Hu, J Z; Orendt, A M; Alderman, D W; Pugmire, R J; Ye, C; Grant, D M

1994-08-01

The magic-angle turning (MAT) experiment introduced by Gan is developed into a powerful and routine method for measuring the principal values of 13C chemical shift tensors in powdered solids. A large-volume MAT probe with stable rotation frequencies down to 22 Hz is described. A triple-echo MAT pulse sequence is introduced to improve the quality of the two-dimensional baseplane. It is shown that measurements of the principal values of chemical shift tensors in complex compounds can be enhanced by using either short contact times or dipolar dephasing pulse sequences to isolate the powder patterns from protonated or non-protonated carbons, respectively. A model compound, 1,2,3-trimethoxybenzene, is used to demonstrate these techniques, and the 13C principal values in 2,3-dimethylnaphthalene and Pocahontas coal are reported as typical examples.

Permanent magnet assembly producing a strong tilted homogeneous magnetic field: towards magic angle field spinning NMR and MRI.

PubMed

Sakellariou, Dimitris; Hugon, Cédric; Guiga, Angelo; Aubert, Guy; Cazaux, Sandrine; Hardy, Philippe

2010-12-01

We introduce a cylindrical permanent magnet design that generates a homogeneous and strong magnetic field having an arbitrary inclination with respect to the axis of the cylinder. The analytical theory of 3 D magnetostatics has been applied to this problem, and a hybrid magnet structure has been designed. This structure contains two magnets producing a longitudinal and transverse component for the magnetic field, whose amplitudes and homogeneities can be fully controlled by design. A simple prototype has been constructed using inexpensive small cube magnets, and its magnetic field has been mapped using Hall and NMR probe sensors. This magnet can, in principle, be used for magic angle field spinning NMR and MRI experiments allowing for metabolic chemical shift profiling in small living animals. Copyright © 2010 John Wiley & Sons, Ltd.

Novel NMR tools to study structure and dynamics of biomembranes.

PubMed

Gawrisch, Klaus; Eldho, Nadukkudy V; Polozov, Ivan V

2002-06-01

Nuclear magnetic resonance (NMR) studies on biomembranes have benefited greatly from introduction of magic angle spinning (MAS) NMR techniques. Improvements in MAS probe technology, combined with the higher magnetic field strength of modern instruments, enables almost liquid-like resolution of lipid resonances. The cross-relaxation rates measured by nuclear Overhauser enhancement spectroscopy (NOESY) provide new insights into conformation and dynamics of lipids with atomic-scale resolution. The data reflect the tremendous motional disorder in the lipid matrix. Transfer of magnetization by spin diffusion along the proton network of lipids is of secondary relevance, even at a long NOESY mixing time of 300 ms. MAS experiments with re-coupling of anisotropic interactions, like the 13C-(1)H dipolar couplings, benefit from the excellent resolution of 13C shifts that enables assignment of the couplings to specific carbon atoms. The traditional 2H NMR experiments on deuterated lipids have higher sensitivity when conducted on oriented samples at higher magnetic field strength. A very large number of NMR parameters from lipid bilayers is now accessible, providing information about conformation and dynamics for every lipid segment. The NMR methods have the sensitivity and resolution to study lipid-protein interaction, lateral lipid organization, and the location of solvents and drugs in the lipid matrix.

Two-dimensional nuclear magnetic resonance of quadrupolar systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Shuanhu

1997-09-01

This dissertation describes two-dimensional nuclear magnetic resonance theory and experiments which have been developed to study quadruples in the solid state. The technique of multiple-quantum magic-angle spinning (MQMAS) is extensively reviewed and expanded upon in this thesis. Specifically, MQMAS is first compared with another technique, dynamic-angle spinning (DAS). The similarity between the two techniques allows us to extend much of the DAS work to the MQMAS case. Application of MQMAS to a series of aluminum containing materials is then presented. The superior resolution enhancement through MQMAS is exploited to detect the five- and six-coordinated aluminum in many aluminosilicate glasses. Combiningmore » the MQMAS method with other experiments, such as HETCOR, greatly expands the possibility of the use of MQMAS to study a large range of problems and is demonstrated in Chapter 5. Finally, the technique switching-angle spinning (SAS) is applied to quadrupolar nuclei to fully characterize a quadrupolar spin system in which all of the 8 NMR parameters are accurately determined. This dissertation is meant to demonstrate that with the combination of two-dimensional NMR concepts and new advanced spinning technologies, a series of multiple-dimensional NMR techniques can be designed to allow a detailed study of quadrupolar nuclei in the solid state.« less

Measurements of relative chemical shift tensor orientations in solid-state NMR: new slow magic angle spinning dipolar recoupling experiments.

PubMed

Jurd, Andrew P S; Titman, Jeremy J

2009-08-28

Solid-state NMR experiments can be used to determine conformational parameters, such as interatomic distances and torsion angles. The latter can be obtained from measurements of the relative orientation of two chemical shift tensors, if the orientation of these with respect to the surrounding bonds is known. In this paper, a new rotor-synchronized magic angle spinning (MAS) dipolar correlation experiment is described which can be used in this way. Because the experiment requires slow MAS rates, a novel recoupling sequence, designed using symmetry principles, is incorporated into the mixing period. This recoupling sequence is based in turn on a new composite cyclic pulse referred to as COAST (for combined offset and anisotropy stabilization). The new COAST-C7(2)(1) sequence is shown to give good theoretical and experimental recoupling efficiency, even when the CSA far exceeds the MAS rate. In this regime, previous recoupling sequences, such as POST-C7(2)(1), exhibit poor recoupling performance. The effectiveness of the new method has been explored by a study of the dipeptide L-phenylalanyl-L-phenylalanine.

Natural abundance high-resolution solid state 2 H NMR spectroscopy

NASA Astrophysics Data System (ADS)

Aliev, Abil E.; Harris, Kenneth D. M.; Apperley, David C.

1994-08-01

We report for the first time an approach for natural abundance solid state 2 H NMR spectroscopy involving magic angle sample spinning (MAS), high-power 1 H decoupling (HPPD) and 1 H- 2 H cross polarization (CP). Taking tetrakis(trimethylsilyl)silane (TTMSS), adamantane, 1-chloroadamantane, hexamethylbenzene (HMB), 2,2-dimethyl-1,3-propanediol (DMPD) and 2-hydroxymethyl-2-methyl-1,3-propanediol (HMPD) as examples, it has been shown that the combination of HPPD and MAS can be applied readily to study rotator phase solids, allowing isotropic peaks arising from chemically inequivalent 2 H nuclei to be resolved. For natural abundance samples of TTMSS and chloroadamantane, it has been shown that 2 H CP/HPPD/MAS NMR experiments, involving polarization transfer from 1 H to 2 H, may provide considerable sensitivity enhancement in comparison with single pulse experiments.

Natural abundance high-resolution solid state 2 H NMR spectroscopy

NASA Astrophysics Data System (ADS)

Aliev, Abil E.; Harris, Kenneth D. M.; Apperley, David C.

1994-08-01

We report for the first time an approach for natural abundance solid state 2H NMR spectroscopy involving magic angle sample spinning (MAS), high-power 1H decoupling (HPPD) and 1H- 2H cross polarization (CP). Taking tetrakis(trimethylsilyl)silane (TTMSS), adamantane, 1-chloroadamantane, hexamethylbenzene (HMB), 2,2-dimethyl-1,3-propanediol (DMPD) and 2-hydroxymethyl-2-methyl-1,3-propanediol (HMPD) as examples, it has been shown that the combination of HPPD and MAS can be applied readily to study rotator phase solids, allowing isotropic peaks arising from chemically inequivalent 2H nuclei to be resolved. For natural abundance samples of TTMSS and chloroadamantane, it has been shown that 2H CP/HPPD/MAS NMR experiments, involving polarization transfer from 1H to 2H, may provide considerable sensitivity enhancement in comparison with single pulse experiments.

Analysis of periprosthetic capsular tissue from women with silicone breast implants by magic-angle spinning NMR.

PubMed

Garrido, L; Young, V L

1999-09-01

The amount of silicone (polydimethylsiloxane [PDMS]) in capsular tissue surgically removed from women with breast implants was measured by using (29)Si and (1)H magic-angle spinning solid-state NMR spectroscopy. Twelve women having smooth surface silicone gel-filled implants, including a subject with "low-bleed" double-lumen implants, had detectable levels of PDMS ranging from 0. 05 to 9.8% silicon in wet tissue (w/w). No silicon-containing compounds other than PDMS were detected. No correlation was found between the amount of PDMS measured in the capsular tissue and the length of implantation time (Pearson correlation coefficient, r = 0. 22). The results showed no relationship between higher amounts of PDMS and capsular contracture (p = 0.74) or other symptoms (p = 0. 53). Magn Reson Med 42:436-441, 1999. Copyright 1999 Wiley-Liss, Inc.

On the use of ultracentrifugal devices for routine sample preparation in biomolecular magic-angle-spinning NMR

PubMed Central

Mandal, Abhishek; Boatz, Jennifer C.; Wheeler, Travis; van der Wel, Patrick C. A.

2017-01-01

A number of recent advances in the field of magic-angle-spinning (MAS) solid-state NMR have enabled its application to a range of biological systems of ever increasing complexity. To retain biological relevance, these samples are increasingly studied in a hydrated state. At the same time, experimental feasibility requires the sample preparation process to attain a high sample concentration within the final MAS rotor. We discuss these considerations, and how they have led to a number of different approaches to MAS NMR sample preparation. We describe our experience of how custom-made (or commercially available) ultracentrifugal devices can facilitate a simple, fast and reliable sample preparation process. A number of groups have since adopted such tools, in some cases to prepare samples for sedimentation-style MAS NMR experiments. Here we argue for a more widespread adoption of their use for routine MAS NMR sample preparation. PMID:28229262

Instrumentation for cryogenic magic angle spinning dynamic nuclear polarization using 90 L of liquid nitrogen per day

NASA Astrophysics Data System (ADS)

Albert, Brice J.; Pahng, Seong Ho; Alaniva, Nicholas; Sesti, Erika L.; Rand, Peter W.; Saliba, Edward P.; Scott, Faith J.; Choi, Eric J.; Barnes, Alexander B.

2017-10-01

Cryogenic sample temperatures can enhance NMR sensitivity by extending spin relaxation times to improve dynamic nuclear polarization (DNP) and by increasing Boltzmann spin polarization. We have developed an efficient heat exchanger with a liquid nitrogen consumption rate of only 90 L per day to perform magic-angle spinning (MAS) DNP experiments below 85 K. In this heat exchanger implementation, cold exhaust gas from the NMR probe is returned to the outer portion of a counterflow coil within an intermediate cooling stage to improve cooling efficiency of the spinning and variable temperature gases. The heat exchange within the counterflow coil is calculated with computational fluid dynamics to optimize the heat transfer. Experimental results using the novel counterflow heat exchanger demonstrate MAS DNP signal enhancements of 328 ± 3 at 81 ± 2 K, and 276 ± 4 at 105 ± 2 K.

Dynamic Nuclear Polarization NMR in Human Cells Using Fluorescent Polarizing Agents.

PubMed

Albert, Brice J; Gao, Chukun; Sesti, Erika L; Saliba, Edward P; Alaniva, Nicholas; Scott, Faith J; Sigurdsson, Snorri Th; Barnes, Alexander B

2018-06-20

Solid-state nuclear magnetic resonance (NMR) enables atomic resolution characterization of molecular structure and dynamics within complex heterogeneous samples, but it is typically insensitive. Dynamic nuclear polarization (DNP) increases NMR signal intensity by orders of magnitude and can be performed in combination with magic angle spinning (MAS) for sensitive, high-resolution spectroscopy. Here we report MAS DNP experiments, for the first time, within intact human cells with >40-fold DNP enhancement and a sample temperature below 6 K. In addition to cryogenic MAS results below 6 K, we also show in-cell DNP enhancements of 57-fold at 90 K. In-cell DNP is demonstrated using biradicals and sterically-shielded monoradicals as polarizing agents. A novel trimodal polarizing agent is introduced for DNP, which contains a nitroxide biradical, a targeting peptide for cell penetration, and a fluorophore for subcellular localization with confocal microscopy. The fluorescent polarizing agent provides in-cell DNP enhancements of 63-fold at a concentration of 2.7 mM. These experiments pave the way for structural characterization of biomolecules in an endogenous cellular context.

Scattering on a rectangular potential barrier in nodal-line Weyl semimetals

NASA Astrophysics Data System (ADS)

Khokhlov, D. A.; Rakhmanov, A. L.; Rozhkov, A. V.

2018-06-01

We investigate single-particle ballistic scattering on a rectangular barrier in the nodal-line Weyl semimetals. Since the system under study has a crystallographic anisotropy, the scattering properties are dependent on mutual orientation of the crystalline axis and the barrier. To account for the anisotropy, we examine two different barrier orientations. It is demonstrated that, for certain angles of incidence, the incoming particle passes through the barrier with probability of unity. This is a manifestation of the Klein tunneling, a familiar phenomenon in the context of graphene and semimetals with Weyl points. However, the Klein tunneling in the Weyl-ring systems is observed when the angle of incidence differs from 90∘, unlike the cases of graphene and Weyl-point semimetals. The reflectionless transmission also occurs for the so-called "magic angles." The values of the magic angles are determined by geometrical resonances between the barrier width and the de Broglie length of the scattered particle. In addition, we show that under certain conditions the wave function of the transmitted and reflected particles may be a superposition of two plane waves with unequal momenta. Such a feature is a consequence of the nontrivial structure of the isoenergy surfaces of the nodal-line semimetals. Conductance of the barrier is briefly discussed.

Performance of the MAGIC telescopes under moonlight

NASA Astrophysics Data System (ADS)

Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.; Arcaro, C.; Babić, A.; Banerjee, B.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Berti, A.; Bhattacharyya, W.; Biasuzzi, B.; Biland, A.; Blanch, O.; Bonnefoy, S.; Bonnoli, G.; Carosi, R.; Carosi, A.; Chatterjee, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Cumani, P.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Lotto, B.; de Oña Wilhelmi, E.; Di Pierro, F.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher Glawion, D.; Elsaesser, D.; Engelkemeier, M.; Fallah Ramazani, V.; Fernández-Barral, A.; Fidalgo, D.; Fonseca, M. V.; Font, L.; Fruck, C.; Galindo, D.; García López, R. J.; Garczarczyk, M.; Gaug, M.; Giammaria, P.; Godinović, N.; Gora, D.; Griffiths, S.; Guberman, D.; Hadasch, D.; Hahn, A.; Hassan, T.; Hayashida, M.; Herrera, J.; Hose, J.; Hrupec, D.; Hughes, G.; Ishio, K.; Konno, Y.; Kubo, H.; Kushida, J.; Kuveždić, D.; Lelas, D.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; Maggio, C.; Majumdar, P.; Makariev, M.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Menzel, U.; Minev, M.; Mirzoyan, R.; Moralejo, A.; Moreno, V.; Moretti, E.; Neustroev, V.; Niedzwiecki, A.; Nievas Rosillo, M.; Nilsson, K.; Ninci, D.; Nishijima, K.; Noda, K.; Nogués, L.; Paiano, S.; Palacio, J.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Paredes-Fortuny, X.; Pedaletti, G.; Peresano, M.; Perri, L.; Persic, M.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Garcia, J. R.; Reichardt, I.; Rhode, W.; Ribó, M.; Rico, J.; Rugliancich, A.; Saito, T.; Satalecka, K.; Schroeder, S.; Schweizer, T.; Sillanpää, A.; Sitarek, J.; Šnidarić, I.; Sobczynska, D.; Stamerra, A.; Strzys, M.; Surić, T.; Takalo, L.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Torres, D. F.; Torres-Albà, N.; Treves, A.; Vanzo, G.; Vazquez Acosta, M.; Vovk, I.; Ward, J. E.; Will, M.; Zarić, D.

2017-09-01

MAGIC, a system of two imaging atmospheric Cherenkov telescopes, achieves its best performance under dark conditions, i.e. in absence of moonlight or twilight. Since operating the telescopes only during dark time would severely limit the duty cycle, observations are also performed when the Moon is present in the sky. Here we develop a dedicated Moon-adapted analysis to characterize the performance of MAGIC under moonlight. We evaluate energy threshold, angular resolution and sensitivity of MAGIC under different background light levels, based on Crab Nebula observations and tuned Monte Carlo simulations. This study includes observations taken under non-standard hardware configurations, such as reducing the camera photomultiplier tubes gain by a factor ∼1.7 (reduced HV settings) with respect to standard settings (nominal HV) or using UV-pass filters to strongly reduce the amount of moonlight reaching the cameras of the telescopes. The Crab Nebula spectrum is correctly reconstructed in all the studied illumination levels, that reach up to 30 times brighter than under dark conditions. The main effect of moonlight is an increase in the analysis energy threshold and in the systematic uncertainties on the flux normalization. The sensitivity degradation is constrained to be below 10%, within 15-30% and between 60 and 80% for nominal HV, reduced HV and UV-pass filter observations, respectively. No worsening of the angular resolution was found. Thanks to observations during moonlight, the maximal duty cycle of MAGIC can be increased from ∼18%, under dark nights only, to up to ∼40% in total with only moderate performance degradation.

MAGIC gamma-ray telescopes hunting for neutrinos and their sources

NASA Astrophysics Data System (ADS)

Góra, D.; Bernardini, E.; Satalecka, K.; Noda, K.; Manganaro, M.; López, M.; MAGIC Collaboration

2017-09-01

The discovery of an astrophysical flux of high-energy neutrinos by the IceCube Collaboration marks a major breakthrough in the ongoing search for the origin of cosmic rays. Presumably, the neutrinos, together with gamma rays, result from pion decay, following hadronic interactions of protons accelerated in astrophysical objects to ultra-relativistic energies. So far, the neutrino sky map shows no significant indication of astrophysical sources. Here, we report first results from follow-up observations, of sky regions where IceCube has detected muon tracks from energetic neutrinos, using the MAGIC telescopes which are sensitive to gamma rays at TeV energies. Furthermore, we show that MAGIC has the potential to distinguish air showers induced by tau neutrinos from the background of hadronic showers in the PeV-EeV energy range, employing a novel analysis method to the data obtained with high-zenith angle observations.

The metabolic profile of lemon juice by proton HR-MAS NMR: the case of the PGI Interdonato Lemon of Messina.

PubMed

Cicero, Nicola; Corsaro, Carmelo; Salvo, Andrea; Vasi, Sebastiano; Giofré, Salvatore V; Ferrantelli, Vincenzo; Di Stefano, Vita; Mallamace, Domenico; Dugo, Giacomo

2015-01-01

We have studied by means of High Resolution Magic Angle Spinning Nuclear Magnetic Resonance (HR-MAS NMR) the metabolic profile of the famous Sicilian lemon known as 'Interdonato Lemon of Messina PGI'. The PGI Interdonato Lemon of Messina possesses high organoleptic and healthy properties and is recognised as one of the most nutrient fruits. In particular, some of its constituents are actively studied for their chemo-preventive and therapeutic properties. In this paper, we have determined by means of HR-MAS NMR spectroscopy the molar concentration of the main metabolites constituent the juice of PGI Interdonato Lemon of Messina in comparison with that of the not-PGI Interdonato Lemon of Turkey. Our aim is to develop an analytical technique, in order to determine a metabolic fingerprint able to reveal commercial frauds in national and international markets.

Supramolecular Amino Acid Based Hydrogels: Probing the Contribution of Additive Molecules using NMR Spectroscopy

PubMed Central

Ramalhete, Susana M.; Nartowski, Karol P.; Sarathchandra, Nichola; Foster, Jamie S.; Round, Andrew N.; Angulo, Jesús

2017-01-01

Abstract Supramolecular hydrogels are composed of self‐assembled solid networks that restrict the flow of water. l‐Phenylalanine is the smallest molecule reported to date to form gel networks in water, and it is of particular interest due to its crystalline gel state. Single and multi‐component hydrogels of l‐phenylalanine are used herein as model materials to develop an NMR‐based analytical approach to gain insight into the mechanisms of supramolecular gelation. Structure and composition of the gel fibres were probed using PXRD, solid‐state NMR experiments and microscopic techniques. Solution‐state NMR studies probed the properties of free gelator molecules in an equilibrium with bound molecules. The dynamics of exchange at the gel/solution interfaces was investigated further using high‐resolution magic angle spinning (HR‐MAS) and saturation transfer difference (STD) NMR experiments. This approach allowed the identification of which additive molecules contributed in modifying the material properties. PMID:28401991

Characterization of Free Surface-Bound and Entrapped Water Environments in Poly(N-Isopropyl Acrylamide) Hydrogels via 1H HRMAS PFG NMR Spectroscopy

DOE PAGES

Alam, Todd Michael; Childress, Kimberly Kay; Pastoor, Kevin; ...

2014-09-19

We found that different water environments in poly(N-isopropyl acrylamide) (PNIPAAm) hydrogels are identified and characterized using 1H high resolution magic angle spinning (HRMAS) nuclear magnetic resonance (NMR). Local water environments corresponding to a “free” highly mobile species, along with waters showing restricted dynamics are resolved in these swollen hydro-gels. For photo-initiated polymerized PNIPAAm gels, an additional entrapped water species is observed. Spin–spin R 2 relaxation experiments support the argument of reduced mobility in the restricted and entrapped water species. Furthermore, by combining pulse field gradient techniques with HRMAS NMR it is possible to directly measure the self-diffusion rate for thesemore » different water environments. The behavior of the heterogeneous water environments through the lower critical solution temperature transition is described.« less

Mechanisms of Dynamic Nuclear Polarization in Insulating Solids

PubMed Central

Can, T.V.; Ni, Q.Z.; Griffin, R.G.

2015-01-01

Dynamic nuclear polarization (DNP) is a technique used to enhance signal intensities in NMR experiments by transferring the high polarization of electrons to their surrounding nuclei. The past decade has witnessed a renaissance in the development of DNP, especially at high magnetic fields, and its application in several areas including biophysics, chemistry, structural biology and materials science. Recent technical and theoretical advances have expanded our understanding of established experiments: for example, the cross effect DNP in samples spinning at the magic angle. Furthermore, new experiments suggest that our understanding of the Overhauser effect and its applicability to insulating solids needs to be re-examined. In this article, we summarize important results of the past few years and provide quantum mechanical explanations underlying these results. We also discuss future directions of DNP and current limitations, including the problem of resolution in protein spectra recorded at 80–100 K. PMID:25797002

NMR Based Cerebrum Metabonomic Analysis Reveals Simultaneous Interconnected Changes during Chick Embryo Incubation.

PubMed

Feng, Yue; Zhu, Hang; Zhang, Xu; Wang, Xuxia; Xu, Fuqiang; Tang, Huiru; Ye, Chaohui; Liu, Maili

2015-01-01

To find out if content changes of the major functional cerebrum metabolites are interconnected and formed a network during the brain development, we obtained high-resolution magic-angle-spinning (HR-MAS) 1H NMR spectra of cerebrum tissues of chick embryo aged from incubation day 10 to 20, and postnatal day 1, and analyzed the data with principal component analysis (PCA). Within the examined time window, 26 biological important molecules were identified and 12 of them changed their relative concentration significantly in a time-dependent manner. These metabolites are generally belonged to three categories, neurotransmitters, nutrition sources, and neuronal or glial markers. The relative concentration changes of the metabolites were interconnected among/between the categories, and, more interestingly, associated with the number and size of Nissl-positive neurons. These results provided valuable biochemical and neurochemical information to understand the development of the embryonic brain.

NMR Based Cerebrum Metabonomic Analysis Reveals Simultaneous Interconnected Changes during Chick Embryo Incubation

PubMed Central

Feng, Yue; Zhu, Hang; Zhang, Xu; Wang, Xuxia; Xu, Fuqiang; Tang, Huiru; Ye, Chaohui; Liu, Maili

2015-01-01

To find out if content changes of the major functional cerebrum metabolites are interconnected and formed a network during the brain development, we obtained high-resolution magic-angle-spinning (HR-MAS) 1H NMR spectra of cerebrum tissues of chick embryo aged from incubation day 10 to 20, and postnatal day 1, and analyzed the data with principal component analysis (PCA). Within the examined time window, 26 biological important molecules were identified and 12 of them changed their relative concentration significantly in a time-dependent manner. These metabolites are generally belonged to three categories, neurotransmitters, nutrition sources, and neuronal or glial markers. The relative concentration changes of the metabolites were interconnected among/between the categories, and, more interestingly, associated with the number and size of Nissl-positive neurons. These results provided valuable biochemical and neurochemical information to understand the development of the embryonic brain. PMID:26485040

Principal component analysis for the comparison of metabolic profiles from human rectal cancer biopsies and colorectal xenografts using high-resolution magic angle spinning 1H magnetic resonance spectroscopy

PubMed Central

Seierstad, Therese; Røe, Kathrine; Sitter, Beathe; Halgunset, Jostein; Flatmark, Kjersti; Ree, Anne H; Olsen, Dag Rune; Gribbestad, Ingrid S; Bathen, Tone F

2008-01-01

Background This study was conducted in order to elucidate metabolic differences between human rectal cancer biopsies and colorectal HT29, HCT116 and SW620 xenografts by using high-resolution magnetic angle spinning (MAS) magnetic resonance spectroscopy (MRS) and for determination of the most appropriate human rectal xenograft model for preclinical MR spectroscopy studies. A further aim was to investigate metabolic changes following irradiation of HT29 xenografts. Methods HR MAS MRS of tissue samples from xenografts and rectal biopsies were obtained with a Bruker Avance DRX600 spectrometer and analyzed using principal component analysis (PCA) and partial least square (PLS) regression analysis. Results and conclusion HR MAS MRS enabled assignment of 27 metabolites. Score plots from PCA of spin-echo and single-pulse spectra revealed separate clusters of the different xenografts and rectal biopsies, reflecting underlying differences in metabolite composition. The loading profile indicated that clustering was mainly based on differences in relative amounts of lipids, lactate and choline-containing compounds, with HT29 exhibiting the metabolic profile most similar to human rectal cancers tissue. Due to high necrotic fractions in the HT29 xenografts, radiation-induced changes were not detected when comparing spectra from untreated and irradiated HT29 xenografts. However, PLS calibration relating spectral data to the necrotic fraction revealed a significant correlation, indicating that necrotic fraction can be assessed from the MR spectra. PMID:18439252

Pulsed field gradient magic angle spinning NMR self-diffusion measurements in liquids

NASA Astrophysics Data System (ADS)

Viel, Stéphane; Ziarelli, Fabio; Pagès, Guilhem; Carrara, Caroline; Caldarelli, Stefano

2008-01-01

Several investigations have recently reported the combined use of pulsed field gradient (PFG) with magic angle spinning (MAS) for the analysis of molecular mobility in heterogeneous materials. In contrast, little attention has been devoted so far to delimiting the role of the extra force field induced by sample rotation on the significance and reliability of self-diffusivity measurements. The main purpose of this work is to examine this phenomenon by focusing on pure liquids for which its impact is expected to be largest. Specifically, we show that self-diffusion coefficients can be accurately determined by PFG MAS NMR diffusion measurements in liquids, provided that specific experimental conditions are met. First, the methodology to estimate the gradient uniformity and to properly calibrate its absolute strength is briefly reviewed and applied on a MAS probe equipped with a gradient coil aligned along the rotor spinning axis, the so-called 'magic angle gradient' coil. Second, the influence of MAS on the outcome of PFG MAS diffusion measurements in liquids is investigated for two distinct typical rotors of different active volumes, 12 and 50 μL. While the latter rotor led to totally unreliable results, especially for low viscosity compounds, the former allowed for the determination of accurate self-diffusion coefficients both for fast and slowly diffusing species. Potential implications of this work are the possibility to measure accurate self-diffusion coefficients of sample-limited mixtures or to avoid radiation damping interferences in NMR diffusion measurements. Overall, the outlined methodology should be of interest to anyone who strives to improve the reliability of MAS diffusion studies, both in homogeneous and heterogeneous media.

Towards high resolution ^1H NMR spectra of tannin colloidal aggregates

NASA Astrophysics Data System (ADS)

Mirabel, M.; Glories, Y.; Pianet, I.; Dufourc, E. J.

1999-10-01

The time dependent colloidal formation of tannins in hydro-alcoholic medium has been studied by 1H-NMR. Line broadening observed with time can be cancelled by making use of magic angle sample spinning (MASS) thus yielding sharp lines that allow structural studies. We used as an example catechin, a constitutive monomer of Bordeaux young red wine tannins. Chemical shift variations of polyphenol protons allow monitoring the time course of aggregation. La formation de tanins colloïdaux au cours du temps, en milieu hydroalcoolique, a été suivie par RMN-^1H. Un élargissement marqué des résonances est observé et peut être supprimé par la rotation de l'échantillon à l'angle magique ce qui ouvre tout un champ d'études structurales sur ces composés colloïdaux. L'exemple proposé est celui de la catéchine, monomère constitutif de tannins présents en grande quantité dans les vins rouges jeunes de Bordeaux. Des variations du déplacement chimique de certains protons polyphénoliques permettent de suivre l'évolution temporelle de l'agrégation.

Spatial reorientation experiments for NMR of solids and partially oriented liquids.

PubMed

Martin, Rachel W; Kelly, John E; Collier, Kelsey A

2015-11-01

Motional reorientation experiments are extensions of Magic Angle Spinning (MAS) where the rotor axis is changed in order to average out, reintroduce, or scale anisotropic interactions (e.g. dipolar couplings, quadrupolar interactions or chemical shift anisotropies). This review focuses on Variable Angle Spinning (VAS), Switched Angle Spinning (SAS), and Dynamic Angle Spinning (DAS), all of which involve spinning at two or more different angles sequentially, either in successive experiments or during a multidimensional experiment. In all of these experiments, anisotropic terms in the Hamiltonian are scaled by changing the orientation of the spinning sample relative to the static magnetic field. These experiments vary in experimental complexity and instrumentation requirements. In VAS, many one-dimensional spectra are collected as a function of spinning angle. In SAS, dipolar couplings and/or chemical shift anisotropies are reintroduced by switching the sample between two different angles, often 0° or 90° and the magic angle, yielding a two-dimensional isotropic-anisotropic correlation spectrum. Dynamic Angle Spinning (DAS) is a related experiment that is used to simultaneously average out the first- and second-order quadrupolar interactions, which cannot be accomplished by spinning at any unique rotor angle in physical space. Although motional reorientation experiments generally require specialized instrumentation and data analysis schemes, some are accessible with only minor modification of standard MAS probes. In this review, the mechanics of each type of experiment are described, with representative examples. Current and historical probe and coil designs are discussed from the standpoint of how each one accomplishes the particular objectives of the experiment(s) it was designed to perform. Finally, applications to inorganic materials and liquid crystals, which present very different experimental challenges, are discussed. The review concludes with perspectives on how motional reorientation experiments can be applied to current problems in chemistry, molecular biology, and materials science, given the many advances in high-field NMR magnets, fast spinning, and sample preparation realized in recent years. Copyright © 2015 Elsevier B.V. All rights reserved.

MagicPlate-512: A 2D silicon detector array for quality assurance of stereotactic motion adaptive radiotherapy.

PubMed

Petasecca, M; Newall, M K; Booth, J T; Duncan, M; Aldosari, A H; Fuduli, I; Espinoza, A A; Porumb, C S; Guatelli, S; Metcalfe, P; Colvill, E; Cammarano, D; Carolan, M; Oborn, B; Lerch, M L F; Perevertaylo, V; Keall, P J; Rosenfeld, A B

2015-06-01

Spatial and temporal resolutions are two of the most important features for quality assurance instrumentation of motion adaptive radiotherapy modalities. The goal of this work is to characterize the performance of the 2D high spatial resolution monolithic silicon diode array named "MagicPlate-512" for quality assurance of stereotactic body radiation therapy (SBRT) and stereotactic radiosurgery (SRS) combined with a dynamic multileaf collimator (MLC) tracking technique for motion compensation. MagicPlate-512 is used in combination with the movable platform HexaMotion and a research version of radiofrequency tracking system Calypso driving MLC tracking software. The authors reconstruct 2D dose distributions of small field square beams in three modalities: in static conditions, mimicking the temporal movement pattern of a lung tumor and tracking the moving target while the MLC compensates almost instantaneously for the tumor displacement. Use of Calypso in combination with MagicPlate-512 requires a proper radiofrequency interference shielding. Impact of the shielding on dosimetry has been simulated by (GEANT)4 and verified experimentally. Temporal and spatial resolutions of the dosimetry system allow also for accurate verification of segments of complex stereotactic radiotherapy plans with identification of the instant and location where a certain dose is delivered. This feature allows for retrospective temporal reconstruction of the delivery process and easy identification of error in the tracking or the multileaf collimator driving systems. A sliding MLC wedge combined with the lung motion pattern has been measured. The ability of the MagicPlate-512 (MP512) in 2D dose mapping in all three modes of operation was benchmarked by EBT3 film. Full width at half maximum and penumbra of the moving and stationary dose profiles measured by EBT3 film and MagicPlate-512 confirm that motion has a significant impact on the dose distribution. Motion, no motion, and motion with MLC tracking profiles agreed within 1 and 0.4 mm, respectively, for all field sizes tested. Use of electromagnetic tracking system generates a fluctuation of the detector baseline up to 10% of the full scale signal requiring a proper shielding strategy. MagicPlate-512 is also able to reconstruct the dose variation pulse-by-pulse in each pixel of the detector. An analysis of the dose transients with motion and motion with tracking shows that the tracking feedback algorithm used for this experiment can compensate effectively only the effect of the slower transient components. The fast changing components of the organ motion can contribute only to discrepancy of the order of 15% in penumbral region while the slower components can change the dose profile up to 75% of the expected dose. MagicPlate-512 is shown to be, potentially, a valid alternative to film or 2D ionizing chambers for quality assurance dosimetry in SRS or SBRT. Its high spatial and temporal resolutions allow for accurate reconstruction of the profile in any conditions with motion and with tracking of the motion. It shows excellent performance to reconstruct the dose deposition in real time or retrospectively as a function of time for detailed analysis of the effect of motion in a specific pixel or area of interest.

Insight into hydrogen bonding of uranyl hydroxide layers and capsules by use of 1H magic-angle spinning NMR spectroscopy [Insight into the hydrogen bonding for uranyl hydroxides using 1H MAS NMR spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alam, Todd M.; Liao, Zuolei; Nyman, May

Solid-state 1H magic-angle spinning (MAS) NMR was used to investigate local proton environments in anhydrous [UO 2(OH) 2] (α-UOH) and hydrated uranyl hydroxide [(UO 2) 4O(OH) 6·5H 2O (metaschoepite). For the metaschoepite material, proton resonances of the μ 2-OH hydroxyl and interlayer waters were resolved, with two-dimensional (2D) double-quantum (DQ) 1H– 1H NMR correlation experiments revealing strong dipolar interactions between these different proton species. The experimental NMR results were combined with first-principles CASTEP GIPAW (gauge including projector-augmented wave) chemical shift calculations to develop correlations between hydrogen-bond strength and observed 1H NMR chemical shifts. Furthermore, these NMR correlations allowed characterization ofmore » local hydrogen-bond environments in uranyl U 24 capsules and of changes in hydrogen bonding that occurred during thermal dehydration of metaschoepite.« less

Biomolecular solid state NMR with magic-angle spinning at 25K.

PubMed

Thurber, Kent R; Tycko, Robert

2008-12-01

A magic-angle spinning (MAS) probe has been constructed which allows the sample to be cooled with helium, while the MAS bearing and drive gases are nitrogen. The sample can be cooled to 25K using roughly 3 L/h of liquid helium, while the 4-mm diameter rotor spins at 6.7 kHz with good stability (+/-5 Hz) for many hours. Proton decoupling fields up to at least 130 kHz can be applied. This helium-cooled MAS probe enables a variety of one-dimensional and two-dimensional NMR experiments on biomolecular solids and other materials at low temperatures, with signal-to-noise proportional to 1/T. We show examples of low-temperature (13)C NMR data for two biomolecular samples, namely the peptide Abeta(14-23) in the form of amyloid fibrils and the protein HP35 in frozen glycerol/water solution. Issues related to temperature calibration, spin-lattice relaxation at low temperatures, paramagnetic doping of frozen solutions, and (13)C MAS NMR linewidths are discussed.

Insight into hydrogen bonding of uranyl hydroxide layers and capsules by use of 1H magic-angle spinning NMR spectroscopy [Insight into the hydrogen bonding for uranyl hydroxides using 1H MAS NMR spectroscopy

DOE PAGES

Alam, Todd M.; Liao, Zuolei; Nyman, May; ...

2016-04-27

Solid-state 1H magic-angle spinning (MAS) NMR was used to investigate local proton environments in anhydrous [UO 2(OH) 2] (α-UOH) and hydrated uranyl hydroxide [(UO 2) 4O(OH) 6·5H 2O (metaschoepite). For the metaschoepite material, proton resonances of the μ 2-OH hydroxyl and interlayer waters were resolved, with two-dimensional (2D) double-quantum (DQ) 1H– 1H NMR correlation experiments revealing strong dipolar interactions between these different proton species. The experimental NMR results were combined with first-principles CASTEP GIPAW (gauge including projector-augmented wave) chemical shift calculations to develop correlations between hydrogen-bond strength and observed 1H NMR chemical shifts. Furthermore, these NMR correlations allowed characterization ofmore » local hydrogen-bond environments in uranyl U 24 capsules and of changes in hydrogen bonding that occurred during thermal dehydration of metaschoepite.« less

MAGIC: A Tool for Combining, Interpolating, and Processing Magnetograms

NASA Technical Reports Server (NTRS)

Allred, Joel

2012-01-01

Transients in the solar coronal magnetic field are ultimately the source of space weather. Models which seek to track the evolution of the coronal field require magnetogram images to be used as boundary conditions. These magnetograms are obtained by numerous instruments with different cadences and resolutions. A tool is required which allows modelers to fmd all available data and use them to craft accurate and physically consistent boundary conditions for their models. We have developed a software tool, MAGIC (MAGnetogram Interpolation and Composition), to perform exactly this function. MAGIC can manage the acquisition of magneto gram data, cast it into a source-independent format, and then perform the necessary spatial and temporal interpolation to provide magnetic field values as requested onto model-defined grids. MAGIC has the ability to patch magneto grams from different sources together providing a more complete picture of the Sun's field than is possible from single magneto grams. In doing this, care must be taken so as not to introduce nonphysical current densities along the seam between magnetograms. We have designed a method which minimizes these spurious current densities. MAGIC also includes a number of post-processing tools which can provide additional information to models. For example, MAGIC includes an interface to the DA VE4VM tool which derives surface flow velocities from the time evolution of surface magnetic field. MAGIC has been developed as an application of the KAMELEON data formatting toolkit which has been developed by the CCMC.

A comparison of various algorithms to extract Magic Formula tyre model coefficients for vehicle dynamics simulations

NASA Astrophysics Data System (ADS)

Vijay Alagappan, A.; Narasimha Rao, K. V.; Krishna Kumar, R.

2015-02-01

Tyre models are a prerequisite for any vehicle dynamics simulation. Tyre models range from the simplest mathematical models that consider only the cornering stiffness to a complex set of formulae. Among all the steady-state tyre models that are in use today, the Magic Formula tyre model is unique and most popular. Though the Magic Formula tyre model is widely used, obtaining the model coefficients from either the experimental or the simulation data is not straightforward due to its nonlinear nature and the presence of a large number of coefficients. A common procedure used for this extraction is the least-squares minimisation that requires considerable experience for initial guesses. Various researchers have tried different algorithms, namely, gradient and Newton-based methods, differential evolution, artificial neural networks, etc. The issues involved in all these algorithms are setting bounds or constraints, sensitivity of the parameters, the features of the input data such as the number of points, noisy data, experimental procedure used such as slip angle sweep or tyre measurement (TIME) procedure, etc. The extracted Magic Formula coefficients are affected by these variants. This paper highlights the issues that are commonly encountered in obtaining these coefficients with different algorithms, namely, least-squares minimisation using trust region algorithms, Nelder-Mead simplex, pattern search, differential evolution, particle swarm optimisation, cuckoo search, etc. A key observation is that not all the algorithms give the same Magic Formula coefficients for a given data. The nature of the input data and the type of the algorithm decide the set of the Magic Formula tyre model coefficients.

Unsaturation level decreased in bone marrow fat of postmenopausal women with low bone density using high resolution magic angle spinning (HRMAS) 1H NMR spectroscopy.

PubMed

Li, Xiaojuan; Shet, Keerthi; Xu, Kaipin; Rodríguez, Juan Pablo; Pino, Ana María; Kurhanewicz, John; Schwartz, Ann; Rosen, Clifford J

2017-12-01

There are increasing evidences suggesting bone marrow adiposity tissue (MAT) plays a critical role in affecting both bone quantity and quality. However, very limited studies that have investigated the association between the composition of MAT and bone mineral density (BMD). The goal of this study was to quantify MAT unsaturation profile of marrow samples from post-menopausal women using ex vivo high-resolution magic angle spinning (HRMAS) proton nuclear magnetic resonance ( 1 H NMR) spectroscopy, and to investigate the relationship between MAT composition and BMD. Bone marrow samples were obtained by iliac crest aspiration during surgical procedures from 24 postmenopausal women (65-89years) who had hip surgery due to bone fracture or arthroplasty. Marrow fat composition parameters, in particular, unsaturation level (UL), mono-unsaturation level (MUL) and saturation level (SL), were quantified using HRMAS 1 H NMR spectroscopy. The patients were classified into three groups based on the DXA BMD T-scores: controls, osteopenia and osteoporosis. Marrow fat composition was compared between these three groups as well as between subjects with and without factures using ANOCOVA, adjusted for age. Subjects with lower BMD (n=17) had significantly lower MUL (P=0.003) and UL (P=0.039), and significantly higher SL (P=0.039) compared to controls (n=7). When separating lower BMD into osteopenia (n=9) and osteoporosis (n=8) groups, subjects with osteopenia had significantly lower MUL (P=0.002) and UL (P=0.010), and significantly higher SL (P=0.010) compared to healthy controls. No significant difference was observed between subjects with osteopenia and osteoporosis. Using HRMAS 1 H NMR, significantly lower unsaturation and significantly higher saturation levels were observed in the marrow fat of subjects with lower BMD. HRMAS 1 H NMR was shown to be a powerful tool for identifying novel MR markers of marrow fat composition that are associated with bone quality and potentially fracture, and other bone pathologies and changes after treatment. A better understanding of the relationship between bone marrow composition and bone quality in humans may identify novel treatment targets, and provide guidance on novel interventions and therapeutic strategies for bone preservation. Copyright © 2017 Elsevier Inc. All rights reserved.

Surface Interactions and Confinement of Methane: A High Pressure Magic Angle Spinning NMR and Computational Chemistry Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ok, Salim; Hoyt, David W.; Andersen, Amity

Characterization and modeling of the molecular-level behavior of simple hydrocarbon gases, such as methane, in the presence of both nonporous and nanoporous mineral matrices allows for predictive understanding of important processes in engineered and natural systems. In this study, we observed changes in local electromagnetic environments of the carbon atoms in methane under conditions of high pressure (up to 130 bar) and moderate temperature (up to 346 K) with 13C magic-angle spinning (MAS) NMR spectroscopy while the methane gas was mixed with two model solid substrates: a fumed nonporous, 12 nm particle size silica and a mesoporous silica with 200more » nm particle size and 4 nm average pore diameter. Examination of the interactions between methane and the silica systems over temperatures and pressures that include the supercritical regime was allowed by a novel high pressure MAS sample containment system, which provided high resolution spectra collected under in situ conditions. There was no significant thermal effects were found for the observed 13C chemical shifts at all pressures studied here (28.2, 32.6, 56.4, 65.1, 112.7, and 130.3 bar) for pure methane. However, the 13C chemical shifts of resonances arising from confined methane changed slightly with changes in temperature in mixtures with mesoporous silica. The chemical shift values of 13C nuclides in methane change measurably as a function of pressure both in the pure state and in mixtures with both silica matrices, with a more pronounced shift when meso-porous silica is present. Molecular-level simulations utilizing GCMC, MD, and DFT confirm qualitatively that the experimentally measured changes are attributed to interactions of methane with the hydroxylated silica surfaces as well as densification of methane within nanopores and on pore surfaces.« less

Surface Interactions and Confinement of Methane: A High Pressure Magic Angle Spinning NMR and Computational Chemistry Study

DOE PAGES

Ok, Salim; Hoyt, David W.; Andersen, Amity; ...

2017-01-18

Characterization and modeling of the molecular-level behavior of simple hydrocarbon gases, such as methane, in the presence of both nonporous and nanoporous mineral matrices allows for predictive understanding of important processes in engineered and natural systems. In this study, we observed changes in local electromagnetic environments of the carbon atoms in methane under conditions of high pressure (up to 130 bar) and moderate temperature (up to 346 K) with 13C magic-angle spinning (MAS) NMR spectroscopy while the methane gas was mixed with two model solid substrates: a fumed nonporous, 12 nm particle size silica and a mesoporous silica with 200more » nm particle size and 4 nm average pore diameter. Examination of the interactions between methane and the silica systems over temperatures and pressures that include the supercritical regime was allowed by a novel high pressure MAS sample containment system, which provided high resolution spectra collected under in situ conditions. There was no significant thermal effects were found for the observed 13C chemical shifts at all pressures studied here (28.2, 32.6, 56.4, 65.1, 112.7, and 130.3 bar) for pure methane. However, the 13C chemical shifts of resonances arising from confined methane changed slightly with changes in temperature in mixtures with mesoporous silica. The chemical shift values of 13C nuclides in methane change measurably as a function of pressure both in the pure state and in mixtures with both silica matrices, with a more pronounced shift when meso-porous silica is present. Molecular-level simulations utilizing GCMC, MD, and DFT confirm qualitatively that the experimentally measured changes are attributed to interactions of methane with the hydroxylated silica surfaces as well as densification of methane within nanopores and on pore surfaces.« less

Surface Interactions and Confinement of Methane: A High Pressure Magic Angle Spinning NMR and Computational Chemistry Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ok, Salim; Hoyt, David W.; Andersen, Amity

Characterization and modeling of the molecular-level behavior of simple hydrocarbon gases, such as methane, in the presence of both nonporous and nano-porous mineral matrices allows for predictive understanding of important processes in engineered and natural systems. In this study, changes in local electromagnetic environments of the carbon atoms in methane under conditions of high pressure (up to 130 bar) and moderate temperature (up to 346 K) were observed with 13C magic-angle spinning (MAS) NMR spectroscopy while the methane gas was mixed with two model solid substrates: a fumed non-porous, 12 nm particle size silica and a mesoporous silica with 200more » nm particle size and 4 nm average pore diameter. Examination of the interactions between methane and the silica systems over temperatures and pressures that include the supercritical regime was allowed by a novel high pressure MAS sample containment system, which provided high resolution spectra collected under in situ conditions. For pure methane, no significant thermal effects were found for the observed 13C chemical shifts at all pressures studied here (28.2 bar, 32.6 bar, 56.4 bar, 65.1 bar, 112.7 bar, and 130.3 bar). However, the 13C chemical shifts of resonances arising from confined methane changed slightly with changes in temperature in mixtures with mesoporous silica. The chemical shift values of 13C nuclides in methane change measurably as a function of pressure both in the pure state and in mixtures with both silica matrices, with a more pronounced shift when meso-porous silica is present. Molecular-level simulations utilizing GCMC, MD and DFT confirm qualitatively that the experimentally measured changes are attributed to interactions of methane with the hydroxylated silica surfaces as well as densification of methane within nanopores and on pore surfaces.« less

Hall Plateaus at magic angles in ultraquantum Bismuth

NASA Astrophysics Data System (ADS)

Benoît, Fauqué.

2009-03-01

The behaviour of a three-dimensional electron gas in the presence of a magnetic field strong enough to put all carriers in the first Landau level (i.e. beyond the quantum limit) is a longstanding question of theoretical condensed matter physics [1]. This issue has been recently explored by two high-field experiments on elemental semi-metal Bismuth. In a first study of transport coefficients (which are dominated by hole-like carriers), the Nernst coefficient presented three unexpected maxima that are concomitant with quasi-plateaux in the Hall coefficient [2]. In a second series of experiments, torque magnetometry (which mainly probes the three Dirac valley electron pockets) detected a field-induced phase transition [3]. The full understanding of the electron and hole behaviours above the quantum limit of pure Bi is therefore still under debate. In this talk, we will present our measurement of the Hall resistivity and torque magnetometry with magnetic field up to 31 T and rotating in the trigonal-bisectrix plane [4]. The Hall response is dominated by the hole pockets according to its sign as well as the period and the angular dependence of its quantum oscillations. In the vicinity of the quantum limit, it presents additional anomalies which are the fingerprints of the electron pockets. We found that for particular orientations of the magnetic field (namely ``magic angles''), the Hall response becomes field-independent within the experimental resolution around 20T. This drastic dependence of the plateaux on the field orientation provides strong constraints for theoretical scenarios. [4pt] [1] Bertrand I. Halperin, Japanese Journal of Applied Physics, 26, Supplement 26-3 (1987).[0pt] [2] Kamran Behnia, Luis Balicas, Yakov Kopelevich, Science, 317, 1729 (2008).[0pt] [3] Lu Li, J. G. Checkelsky, Y. S. Hor, C. Uher, A. F. Hebard, R. J. Cava, and N. P. Ong , Science, 321, 5888 (2008).[0pt] [4] Benoît Fauqu'e, Luis Balicas, Ilya Sheikin, Jean Paul Issi and Kamran Behnia, to be published

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petasecca, M., E-mail: marcop@uow.edu.au; Newall, M. K.; Aldosari, A. H.

Purpose: Spatial and temporal resolutions are two of the most important features for quality assurance instrumentation of motion adaptive radiotherapy modalities. The goal of this work is to characterize the performance of the 2D high spatial resolution monolithic silicon diode array named “MagicPlate-512” for quality assurance of stereotactic body radiation therapy (SBRT) and stereotactic radiosurgery (SRS) combined with a dynamic multileaf collimator (MLC) tracking technique for motion compensation. Methods: MagicPlate-512 is used in combination with the movable platform HexaMotion and a research version of radiofrequency tracking system Calypso driving MLC tracking software. The authors reconstruct 2D dose distributions of smallmore » field square beams in three modalities: in static conditions, mimicking the temporal movement pattern of a lung tumor and tracking the moving target while the MLC compensates almost instantaneously for the tumor displacement. Use of Calypso in combination with MagicPlate-512 requires a proper radiofrequency interference shielding. Impact of the shielding on dosimetry has been simulated by GEANT4 and verified experimentally. Temporal and spatial resolutions of the dosimetry system allow also for accurate verification of segments of complex stereotactic radiotherapy plans with identification of the instant and location where a certain dose is delivered. This feature allows for retrospective temporal reconstruction of the delivery process and easy identification of error in the tracking or the multileaf collimator driving systems. A sliding MLC wedge combined with the lung motion pattern has been measured. The ability of the MagicPlate-512 (MP512) in 2D dose mapping in all three modes of operation was benchmarked by EBT3 film. Results: Full width at half maximum and penumbra of the moving and stationary dose profiles measured by EBT3 film and MagicPlate-512 confirm that motion has a significant impact on the dose distribution. Motion, no motion, and motion with MLC tracking profiles agreed within 1 and 0.4 mm, respectively, for all field sizes tested. Use of electromagnetic tracking system generates a fluctuation of the detector baseline up to 10% of the full scale signal requiring a proper shielding strategy. MagicPlate-512 is also able to reconstruct the dose variation pulse-by-pulse in each pixel of the detector. An analysis of the dose transients with motion and motion with tracking shows that the tracking feedback algorithm used for this experiment can compensate effectively only the effect of the slower transient components. The fast changing components of the organ motion can contribute only to discrepancy of the order of 15% in penumbral region while the slower components can change the dose profile up to 75% of the expected dose. Conclusions: MagicPlate-512 is shown to be, potentially, a valid alternative to film or 2D ionizing chambers for quality assurance dosimetry in SRS or SBRT. Its high spatial and temporal resolutions allow for accurate reconstruction of the profile in any conditions with motion and with tracking of the motion. It shows excellent performance to reconstruct the dose deposition in real time or retrospectively as a function of time for detailed analysis of the effect of motion in a specific pixel or area of interest.« less

Resolution enhancement using a new multiple-pulse decoupling sequence for quadrupolar nuclei.

PubMed

Delevoye, L; Trébosc, J; Gan, Z; Montagne, L; Amoureux, J-P

2007-05-01

A new decoupling composite pulse sequence is proposed to remove the broadening on spin S=1/2 magic-angle spinning (MAS) spectra arising from the scalar coupling with a quadrupolar nucleus I. It is illustrated on the (31)P spectrum of an aluminophosphate, AlPO(4)-14, which is broadened by the presence of (27)Al/(31)P scalar couplings. The multiple-pulse (MP) sequence has the advantage over the continuous wave (CW) irradiation to efficiently annul the scalar dephasing without reintroducing the dipolar interaction. The MP decoupling sequence is first described in a rotor-synchronised version (RS-MP) where one parameter only needs to be adjusted. It clearly avoids the dipolar recoupling in order to achieve a better resolution than using the CW sequence. In a second improved version, the MP sequence is experimentally studied in the vicinity of the perfect rotor-synchronised conditions. The linewidth at half maximum (FWHM) of 65 Hz using (27)Al CW decoupling decreases to 48 Hz with RS-MP decoupling and to 30 Hz with rotor-asynchronised MP (RA-MP) decoupling. The main phenomena are explained using both experimental results and numerical simulations.

Irrigation, fertilization and initial substrate quality effects on decomposing Loblolly pine litter chemistry

Treesearch

Felipe G. Sanchez

2004-01-01

Changes in carbon chemistry (i.e., carbon compound classes such as aromatics, phenolics, etc.) of loblolly pine (Pinus taeda L.) litter were examined during three years of decomposition under factorial combinations of irrigation and fertilization treatments. Cross polarization magic angle spinning 13C nuclear magnetic resonance...

Correlated insulator behaviour at half-filling in magic-angle graphene superlattices

NASA Astrophysics Data System (ADS)

Cao, Yuan; Fatemi, Valla; Demir, Ahmet; Fang, Shiang; Tomarken, Spencer L.; Luo, Jason Y.; Sanchez-Yamagishi, Javier D.; Watanabe, Kenji; Taniguchi, Takashi; Kaxiras, Efthimios; Ashoori, Ray C.; Jarillo-Herrero, Pablo

2018-04-01

A van der Waals heterostructure is a type of metamaterial that consists of vertically stacked two-dimensional building blocks held together by the van der Waals forces between the layers. This design means that the properties of van der Waals heterostructures can be engineered precisely, even more so than those of two-dimensional materials. One such property is the ‘twist’ angle between different layers in the heterostructure. This angle has a crucial role in the electronic properties of van der Waals heterostructures, but does not have a direct analogue in other types of heterostructure, such as semiconductors grown using molecular beam epitaxy. For small twist angles, the moiré pattern that is produced by the lattice misorientation between the two-dimensional layers creates long-range modulation of the stacking order. So far, studies of the effects of the twist angle in van der Waals heterostructures have concentrated mostly on heterostructures consisting of monolayer graphene on top of hexagonal boron nitride, which exhibit relatively weak interlayer interaction owing to the large bandgap in hexagonal boron nitride. Here we study a heterostructure consisting of bilayer graphene, in which the two graphene layers are twisted relative to each other by a certain angle. We show experimentally that, as predicted theoretically, when this angle is close to the ‘magic’ angle the electronic band structure near zero Fermi energy becomes flat, owing to strong interlayer coupling. These flat bands exhibit insulating states at half-filling, which are not expected in the absence of correlations between electrons. We show that these correlated states at half-filling are consistent with Mott-like insulator states, which can arise from electrons being localized in the superlattice that is induced by the moiré pattern. These properties of magic-angle-twisted bilayer graphene heterostructures suggest that these materials could be used to study other exotic many-body quantum phases in two dimensions in the absence of a magnetic field. The accessibility of the flat bands through electrical tunability and the bandwidth tunability through the twist angle could pave the way towards more exotic correlated systems, such as unconventional superconductors and quantum spin liquids.

Biopolymer nanocomposite films reinforced with nanocellulose whiskers

Treesearch

Amit Saxena; Marcus Foston; Mohamad Kassaee; Thomas J. Elder; Arthur J. Ragauskas

2011-01-01

A xylan nanocomposite film with improved strength and barrier properties was prepared by a solution casting using nanocellulose whiskers as a reinforcing agent. The 13C cross-polarization magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR) analysis of the spectral data obtained for the NCW/xylan nanocomposite films indicated the signal intensity originating...

Magic-angle spinning NMR of a class I filamentous bacteriophage virus.

PubMed

Abramov, Gili; Morag, Omry; Goldbourt, Amir

2011-08-11

The fd bacteriophage is a filamentous virus that is widely used for bio- and nanotechnology applications ranging from phage display to battery materials. The possibility of obtaining a detailed description of its structural properties regardless of its state is therefore essential not only for understanding its physical arrangement and its bacterial infection process but also for many other applications. Here we present a study of the fd phage by magic-angle spinning solid-state NMR. While current structures rely on a Y21M mutant, experiments performed on a strain bearing a wild-type capsid report on high symmetry of the phage and lack of explicit subunit polymorphism. Chemical shift analysis confirmed that the coat protein mostly consists of a rigid right-handed curved α-helix (residues 6-47 of 50), preceded by a flexible loop-structured N-terminus. We were able to qualitatively assign the resonances belonging to the DNA, including the deoxyribose sugars and the thymine bases. These chemical shifts are consistent with base stacking and a C2'-endo/C3'-exo sugar pucker. © 2011 American Chemical Society

A unified heteronuclear decoupling strategy for magic-angle-spinning solid-state NMR spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Equbal, Asif; Bjerring, Morten; Nielsen, Niels Chr., E-mail: madhu@tifr.res.in, E-mail: ncn@inano.au.dk

2015-05-14

A unified strategy of two-pulse based heteronuclear decoupling for solid-state magic-angle spinning nuclear magnetic resonance is presented. The analysis presented here shows that different decoupling sequences like two-pulse phase-modulation (TPPM), X-inverse-X (XiX), and finite pulse refocused continuous wave (rCW{sup A}) are basically specific solutions of a more generalized decoupling scheme which incorporates the concept of time-modulation along with phase-modulation. A plethora of other good decoupling conditions apart from the standard, TPPM, XiX, and rCW{sup A} decoupling conditions are available from the unified decoupling approach. The importance of combined time- and phase-modulation in order to achieve the best decoupling conditions ismore » delineated. The consequences of different indirect dipolar interactions arising from cross terms comprising of heteronuclear and homonuclear dipolar coupling terms and also those between heteronuclear dipolar coupling and chemical-shift anisotropy terms are presented in order to unfold the effects of anisotropic interactions under different decoupling conditions. Extensive numerical simulation results are corroborated with experiments on standard amino acids.« less

Solid state nuclear magnetic resonance with magic-angle spinning and dynamic nuclear polarization below 25 K

PubMed Central

Thurber, Kent R.; Potapov, Alexey; Yau, Wai-Ming; Tycko, Robert

2012-01-01

We describe an apparatus for solid state nuclear magnetic resonance (NMR) with dynamic nuclear polarization (DNP) and magic-angle spinning (MAS) at 20–25 K and 9.4 Tesla. The MAS NMR probe uses helium to cool the sample space and nitrogen gas for MAS drive and bearings, as described earlier (Thurber et al., J. Magn. Reson. 2008) [1], but also includes a corrugated waveguide for transmission of microwaves from below the probe to the sample. With a 30 mW circularly polarized microwave source at 264 GHz, MAS at 6.8 kHz, and 21 K sample temperature, greater than 25-fold enhancements of cross-polarized 13C NMR signals are observed in spectra of frozen glycerol/water solutions containing the triradical dopant DOTOPA-TEMPO when microwaves are applied. As demonstrations, we present DNP-enhanced one-dimensional and two-dimensional 13C MAS NMR spectra of frozen solutions of uniformly 13C-labeled L-alanine and melittin, a 26-residue helical peptide that we have synthesized with four uniformly 13C-labeled amino acids. PMID:23238592

Systematic evaluation of heteronuclear spin decoupling in solid-state NMR at the rotary-resonance conditions in the regime of fast magic-angle spinning

NASA Astrophysics Data System (ADS)

Sharma, Kshama; Madhu, P. K.; Agarwal, Vipin

2016-09-01

The performance of heteronuclear spin decoupling sequences in solid-state NMR severely degrades when the proton radiofrequency (RF) nutation frequencies (ν1) are close to or at multiples of magic-angle spinning (MAS) frequency (νr) that are referred to as rotary-resonance recoupling conditions (ν1 = n · νr). Recently, two schemes, namely, PISSARRO and rCWApA, have been shown to be less affected by the problem of MAS and RF interference, specifically at the n = 2 rotary-resonance recoupling condition, especially in the fast MAS regime. Here, we systematically evaluate the loss in intensity of several heteronuclear spin decoupling sequences at the n = 1, 2 conditions compared to high-power decoupling in the fast-MAS regime. We propose that in the fast-MAS regime (above 40 kHz) the entire discussion about RF and MAS interference can be avoided by using appropriate low-power decoupling sequences which give comparable performance to decoupling sequences with high-power 1H irradiation of ca.195 kHz.

Measurement of sample temperatures under magic-angle spinning from the chemical shift and spin-lattice relaxation rate of 79Br in KBr powder

PubMed Central

Thurber, Kent R.; Tycko, Robert

2009-01-01

Accurate determination of sample temperatures in solid state nuclear magnetic resonance (NMR) with magic-angle spinning (MAS) can be problematic, particularly because frictional heating and heating by radio-frequency irradiation can make the internal sample temperature significantly different from the temperature outside the MAS rotor. This paper demonstrates the use of 79Br chemical shifts and spin-lattice relaxation rates in KBr powder as temperature-dependent parameters for the determination of internal sample temperatures. Advantages of this method include high signal-to-noise, proximity of the 79Br NMR frequency to that of 13C, applicability from 20 K to 320 K or higher, and simultaneity with adjustment of the MAS axis direction. We show that spin-lattice relaxation in KBr is driven by a quadrupolar mechanism. We demonstrate a simple approach to including KBr powder in hydrated samples, such as biological membrane samples, hydrated amyloid fibrils, and hydrated microcrystalline proteins, that allows direct assessment of the effects of frictional and radio-frequency heating under experimentally relevant conditions. PMID:18930418

Measurement of sample temperatures under magic-angle spinning from the chemical shift and spin-lattice relaxation rate of 79Br in KBr powder.

PubMed

Thurber, Kent R; Tycko, Robert

2009-01-01

Accurate determination of sample temperatures in solid state nuclear magnetic resonance (NMR) with magic-angle spinning (MAS) can be problematic, particularly because frictional heating and heating by radio-frequency irradiation can make the internal sample temperature significantly different from the temperature outside the MAS rotor. This paper demonstrates the use of (79)Br chemical shifts and spin-lattice relaxation rates in KBr powder as temperature-dependent parameters for the determination of internal sample temperatures. Advantages of this method include high signal-to-noise, proximity of the (79)Br NMR frequency to that of (13)C, applicability from 20 K to 320 K or higher, and simultaneity with adjustment of the MAS axis direction. We show that spin-lattice relaxation in KBr is driven by a quadrupolar mechanism. We demonstrate a simple approach to including KBr powder in hydrated samples, such as biological membrane samples, hydrated amyloid fibrils, and hydrated microcrystalline proteins, that allows direct assessment of the effects of frictional and radio-frequency heating under experimentally relevant conditions.

Solid state nuclear magnetic resonance with magic-angle spinning and dynamic nuclear polarization below 25 K.

PubMed

Thurber, Kent R; Potapov, Alexey; Yau, Wai-Ming; Tycko, Robert

2013-01-01

We describe an apparatus for solid state nuclear magnetic resonance (NMR) with dynamic nuclear polarization (DNP) and magic-angle spinning (MAS) at 20-25 K and 9.4 Tesla. The MAS NMR probe uses helium to cool the sample space and nitrogen gas for MAS drive and bearings, as described earlier, but also includes a corrugated waveguide for transmission of microwaves from below the probe to the sample. With a 30 mW circularly polarized microwave source at 264 GHz, MAS at 6.8 kHz, and 21 K sample temperature, greater than 25-fold enhancements of cross-polarized (13)C NMR signals are observed in spectra of frozen glycerol/water solutions containing the triradical dopant DOTOPA-TEMPO when microwaves are applied. As demonstrations, we present DNP-enhanced one-dimensional and two-dimensional (13)C MAS NMR spectra of frozen solutions of uniformly (13)C-labeled l-alanine and melittin, a 26-residue helical peptide that we have synthesized with four uniformly (13)C-labeled amino acids. Published by Elsevier Inc.

Strong-coupling induced damping of spin-echo modulations in magic-angle-spinning NMR: Implications for J coupling measurements in disordered solids

NASA Astrophysics Data System (ADS)

Guerry, Paul; Brown, Steven P.; Smith, Mark E.

2017-10-01

In the context of improving J coupling measurements in disordered solids, strong coupling effects have been investigated in the spin-echo and refocused INADEQUATE spin-echo (REINE) modulations of three- and four-spin systems under magic-angle-spinning (MAS), using density matrix simulations and solid-state NMR experiments on a cadmium phosphate glass. Analytical models are developed for the different modulation regimes, which are shown to be distinguishable in practice using Akaike's information criterion. REINE modulations are shown to be free of the damping that occurs for spin-echo modulations when the observed spin has the same isotropic chemical shift as its neighbour. Damping also occurs when the observed spin is bonded to a strongly-coupled pair. For mid-chain units, the presence of both direct and relayed damping makes both REINE and spin-echo modulations impossible to interpret quantitatively. We nonetheless outline how a qualitative comparison of the modulation curves can provide valuable information on disordered networks, possibly also pertaining to dynamic effects therein.

A High-Resolution 3D Separated-Local-Field Experiment by Means of Magic-Angle Turning

PubMed

Hu; Alderman; Pugmire; Grant

1997-05-01

A 3D separated-local-field (SLF) experiment based on the 2D PHORMAT technique is described. In the 3D experiment, the conventional 2D SLF powder pattern for each chemically inequivalent carbon is separated according to their different isotropic chemical shifts. The dipolar coupling constant of a C-H pair, hence the bond distance, and the relative orientation of the chemical-shift tensor to the C-H vector can all be determined for the protonated carbons with a single measurement. As the sample turns at only about 30 Hz in a MAT experiment, the SLF patterns obtained approach those of a stationary sample, and an accuracy in the measurement similar to that obtained on a stationary sample is expected. The technique is demonstrated on 2,6-dimethoxynaphthalene, where the 13 C-1 H separated-local-field powder patterns for the six chemically inequivalent carbons are clearly identified and measured. The observed dipolar coupling for the methoxy carbon is effectively reduced by the fast rotation of the group about its C3 symmetry axis. The average angle between the C-H bond direction and the C3 rotation axis in the OCH3 group is found to be about 66°.

UTE bi-component analysis of T2* relaxation in articular cartilage

PubMed Central

Shao, H.; Chang, E.Y.; Pauli, C.; Zanganeh, S.; Bae, W.; Chung, C.B.; Tang, G.; Du, J.

2015-01-01

SUMMARY Objectives To determine T2* relaxation in articular cartilage using ultrashort echo time (UTE) imaging and bi-component analysis, with an emphasis on the deep radial and calcified cartilage. Methods Ten patellar samples were imaged using two-dimensional (2D) UTE and Car-Purcell-Meiboom-Gill (CPMG) sequences. UTE images were fitted with a bi-component model to calculate T2* and relative fractions. CPMG images were fitted with a single-component model to calculate T2. The high signal line above the subchondral bone was regarded as the deep radial and calcified cartilage. Depth and orientation dependence of T2*, fraction and T2 were analyzed with histopathology and polarized light microscopy (PLM), confirming normal regions of articular cartilage. An interleaved multi-echo UTE acquisition scheme was proposed for in vivo applications (n = 5). Results The short T2* values remained relatively constant across the cartilage depth while the long T2* values and long T2* fractions tended to increase from subchondral bone to the superficial cartilage. Long T2*s and T2s showed significant magic angle effect for all layers of cartilage from the medial to lateral facets, while the short T2* values and T2* fractions are insensitive to the magic angle effect. The deep radial and calcified cartilage showed a mean short T2* of 0.80 ± 0.05 ms and short T2* fraction of 39.93 ± 3.05% in vitro, and a mean short T2* of 0.93 ± 0.58 ms and short T2* fraction of 35.03 ± 4.09% in vivo. Conclusion UTE bi-component analysis can characterize the short and long T2* values and fractions across the cartilage depth, including the deep radial and calcified cartilage. The short T2* values and T2* fractions are magic angle insensitive. PMID:26382110

Atomic structure and hierarchical assembly of a cross-β amyloid fibril

PubMed Central

Fitzpatrick, Anthony W. P.; Debelouchina, Galia T.; Bayro, Marvin J.; Clare, Daniel K.; Caporini, Marc A.; Bajaj, Vikram S.; Jaroniec, Christopher P.; Wang, Luchun; Ladizhansky, Vladimir; Müller, Shirley A.; MacPhee, Cait E.; Waudby, Christopher A.; Mott, Helen R.; De Simone, Alfonso; Knowles, Tuomas P. J.; Saibil, Helen R.; Vendruscolo, Michele; Orlova, Elena V.; Griffin, Robert G.; Dobson, Christopher M.

2013-01-01

The cross-β amyloid form of peptides and proteins represents an archetypal and widely accessible structure consisting of ordered arrays of β-sheet filaments. These complex aggregates have remarkable chemical and physical properties, and the conversion of normally soluble functional forms of proteins into amyloid structures is linked to many debilitating human diseases, including several common forms of age-related dementia. Despite their importance, however, cross-β amyloid fibrils have proved to be recalcitrant to detailed structural analysis. By combining structural constraints from a series of experimental techniques spanning five orders of magnitude in length scale—including magic angle spinning nuclear magnetic resonance spectroscopy, X-ray fiber diffraction, cryoelectron microscopy, scanning transmission electron microscopy, and atomic force microscopy—we report the atomic-resolution (0.5 Å) structures of three amyloid polymorphs formed by an 11-residue peptide. These structures reveal the details of the packing interactions by which the constituent β-strands are assembled hierarchically into protofilaments, filaments, and mature fibrils. PMID:23513222

Dynamic Nuclear Polarization and other magnetic ideas at EPFL.

PubMed

Bornet, Aurélien; Milani, Jonas; Wang, Shutao; Mammoli, Daniele; Buratto, Roberto; Salvi, Nicola; Segaw, Takuya F; Vitzthum, Veronika; Miéville, Pascal; Chinthalapalli, Srinivas; Perez-Linde, Angel J; Carnevale, Diego; Jannin, Sami; Caporinia, Marc; Ulzega, Simone; Rey, Martial; Bodenhausen, Geoffrey

2012-01-01

Although nuclear magnetic resonance (NMR) can provide a wealth of information, it often suffers from a lack of sensitivity. Dynamic Nuclear Polarization (DNP) provides a way to increase the polarization and hence the signal intensities in NMR spectra by transferring the favourable electron spin polarization of paramagnetic centres to the surrounding nuclear spins through appropriate microwave irradiation. In our group at EPFL, two complementary DNP techniques are under investigation: the combination of DNP with magic angle spinning at temperatures near 100 K ('MAS-DNP'), and the combination of DNP at 1.2 K with rapid heating followed by the transfer of the sample to a high-resolution magnet ('dissolution DNP'). Recent applications of MAS-DNP to surfaces, as well as new developments of magnetization transfer of (1)H to (13)C at 1.2 K prior to dissolution will illustrate the work performed in our group. A second part of the paper will give an overview of some 'non-enhanced' activities of our laboratory in liquid- and solid-state NMR.

PGI chicory (Cichorium intybus L.) traceability by means of HRMAS-NMR spectroscopy: a preliminary study.

PubMed

Ritota, Mena; Casciani, Lorena; Valentini, Massimiliano

2013-05-01

Analytical traceability of PGI and PDO foods (Protected Geographical Indication and Protected Denomination Origin respectively) is one of the most challenging tasks of current applied research. Here we proposed a metabolomic approach based on the combination of (1)H high-resolution magic angle spinning-nuclear magnetic resonance (HRMAS-NMR) spectroscopy with multivariate analysis, i.e. PLS-DA, as a reliable tool for the traceability of Italian PGI chicories (Cichorium intybus L.), i.e. Radicchio Rosso di Treviso and Radicchio Variegato di Castelfranco, also known as red and red-spotted, respectively. The metabolic profile was gained by means of HRMAS-NMR, and multivariate data analysis allowed us to build statistical models capable of providing clear discrimination among the two varieties and classification according to the geographical origin. Based on Variable Importance in Projection values, the molecular markers for classifying the different types of red chicories analysed were found accounting for both the cultivar and the place of origin. © 2012 Society of Chemical Industry.

Moderate MAS enhances local (1)H spin exchange and spin diffusion.

PubMed

Roos, Matthias; Micke, Peter; Saalwächter, Kay; Hempel, Günter

2015-11-01

Proton NMR spin-diffusion experiments are often combined with magic-angle spinning (MAS) to achieve higher spectral resolution of solid samples. Here we show that local proton spin diffusion can indeed become faster at low (<10 kHz) spinning rates as compared to static conditions. Spin diffusion under static conditions can thus be slower than the often referred value of 0.8 nm(2)/ms, which was determined using slow MAS (Clauss et al., 1993). The enhancement of spin diffusion by slow MAS relies on the modulation of the orientation-dependent dipolar couplings during sample rotation and goes along with transient level crossings in combination with dipolar truncation. The experimental finding and its explanation is supported by density matrix simulations, and also emphasizes the sensitivity of spin diffusion to the local coupling topology. The amplification of spin diffusion by slow MAS cannot be explained by any model based on independent spin pairs; at least three spins have to be considered. Copyright © 2015 Elsevier Inc. All rights reserved.

Synthesis of nanometer-sized sodalite without adding organic additives.

PubMed

Fan, Wei; Morozumi, Kazumasa; Kimura, Riichiro; Yokoi, Toshiyuki; Okubo, Tatsuya

2008-06-01

Aggregates (80 nm) of sodalite nanocrystals with crystallite sizes ranging from 20 to 40 nm have been synthesized from a sodium aluminosilicate solution at low temperature, without adding any organic additives, while paying attention to the key factors for the synthesis of nanosized zeolite crystals. The physical properties of nanosized sodalite crystals were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, 29Si solid-state magic-angle spinning (MAS) NMR, and N2 adsorption. As expected, the external surface area of nanosized sodalite crystals is significantly increased compared with that of microsized sodalite crystals. The size of synthesized sodalite crystals can be controlled from 20 nm to 10 microm. It is found that the preparation of a homogeneous aluminosilicate solution followed by the formation of an aluminosilicate hard gel by adjusting the initial composition, for example, SiO2/Al2O3 and Na2O/H2O ratios, is critical for synthesis.

Proton-Based Ultrafast Magic Angle Spinning Solid-State NMR Spectroscopy.

PubMed

Zhang, Rongchun; Mroue, Kamal H; Ramamoorthy, Ayyalusamy

2017-04-18

Protons are vastly abundant in a wide range of exciting macromolecules and thus can be a powerful probe to investigate the structure and dynamics at atomic resolution using solid-state NMR (ssNMR) spectroscopy. Unfortunately, the high signal sensitivity, afforded by the high natural-abundance and high gyromagnetic ratio of protons, is greatly compromised by severe line broadening due to the very strong 1 H- 1 H dipolar couplings. As a result, protons are rarely used, in spite of the desperate need for enhancing the sensitivity of ssNMR to study a variety of systems that are not amenable for high resolution investigation using other techniques including X-ray crystallography, cryo-electron microscopy, and solution NMR spectroscopy. Thanks to the remarkable improvement in proton spectral resolution afforded by the significant advances in magic-angle-spinning (MAS) probe technology, 1 H ssNMR spectroscopy has recently attracted considerable attention in the structural and dynamics studies of various molecular systems. However, it still remains a challenge to obtain narrow 1 H spectral lines, especially from proteins, without resorting to deuteration. In this Account, we review recent proton-based ssNMR strategies that have been developed in our laboratory to further improve proton spectral resolution without resorting to chemical deuteration for the purposes of gaining atomistic-level insights into molecular structures of various crystalline solid systems, using small molecules and peptides as illustrative examples. The proton spectral resolution enhancement afforded by the ultrafast MAS frequencies up to 120 kHz is initially discussed, followed by a description of an ensemble of multidimensional NMR pulse sequences, all based on proton detection, that have been developed to obtain in-depth information from dipolar couplings and chemical shift anisotropy (CSA). Simple single channel multidimensional proton NMR experiments could be performed to probe the proximity of protons for structure determination using 1 H- 1 H dipolar couplings and to evaluate the changes in chemical environments as well as the relative orientation to the external magnetic field using proton CSA. Due to the boost in signal sensitivity enabled by proton detection under ultrafast MAS, by virtue of high proton natural abundance and gyromagnetic ratio, proton-detected multidimensional experiments involving low-γ nuclei can now be accomplished within a reasonable time, while the higher dimension also offers additional resolution enhancement. In addition, the application of proton-based ssNMR spectroscopy under ultrafast MAS in various challenging and crystalline systems is also presented. Finally, we briefly discuss the limitations and challenges pertaining to proton-based ssNMR spectroscopy under ultrafast MAS conditions, such as the presence of high-order dipolar couplings, friction-induced sample heating, and limited sample volume. Although there are still a number of challenges that must be circumvented by further developments in radio frequency pulse sequences, MAS probe technology and approaches to prepare NMR-friendly samples, proton-based ssNMR has already gained much popularity in various research domains, especially in proteins where uniform or site-selective deuteration can be relatively easily achieved. In addition, implementation of the recently developed fast data acquisition approaches would also enable further developments in the design and applications of proton-based ultrafast MAS multidimensional ssNMR techniques.

Model analysis for the MAGIC telescope

NASA Astrophysics Data System (ADS)

Mazin, D.; Bigongiari, C.; Goebel, F.; Moralejo, A.; Wittek, W.

The MAGIC Collaboration operates the 17m imaging Cherenkov telescope on the Canary island La Palma. The main goal of the experiment is an energy threshold below 100 GeV for primary gamma rays. The new analysis technique (model analysis) takes advantage of the high resolution (both in space and time) camera by fitting the averaged expected templates of the shower development to the measured shower images in the camera. This approach allows to recognize and reconstruct images just above the level of the night sky background light fluctuations. Progress and preliminary results of the model analysis technique will be presented.

Measurement and interpretation of electron angle at MABE beam stop

NASA Astrophysics Data System (ADS)

Sanford, T. W. L.; Coleman, P. D.; Poukey, J. W.

1985-02-01

The mean angle of incidence at the beam stop of a 60 kA, 7 MV annular electron beam, in the 20 kG guide field of the MABE accelerator, was determined. Radiation dose measured in TLD arrays mounted downstream of the stop is compared with the radiation dose expected using a CYLTRAN Monte Carlo simulation of the electron/photon transport in the stop as a function of incident angles and energies. All radiation profiles measured are well fit, if the electrons are assumed to be incident with a polar angle theta of 15(0) + or - 2(0). A comparison of theta with that expected from the Adler-Miller model, and a MAGIC code simulation of beam behavior at the stop enables the mean transverse beam velocity to be estimated.

Measurement of electron angle at MABE beam stop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanford, T.W.L.; Coleman, P.D.; Poukey, J.W.

1984-01-01

The mean angle of incidence at the beam stop of a 60 KA, 7 MV annular electron beam, in the 20 kg guide field of the MABE accelerator, is determined. Radiation measured in TLD arrays mounted downstream of the stop is compared with the radiation expected using a CYLTRAN Monte Carlo simulation of the electron/photon transport in the stop as a function of incident angles and energies. All radiation profiles measured are well fit, if the electrons are assumed to be incident with a polar angle theta of 15/sup 0/ +- 2/sup 0/. Comparing theta with that expected from themore » Adler-Miller model, and a MAGIC code simulation of beam behavior at the stop enables the mean transverse beam velocity to be estimated.« less

Quantum phases of quadrupolar Fermi gases in coupled one-dimensional systems

NASA Astrophysics Data System (ADS)

Huang, Wen-Min; Lahrz, M.; Mathey, L.

2014-01-01

Following the recent proposal to create quadrupolar gases [Bhongale et al., Phys. Rev. Lett. 110, 155301 (2013), 10.1103/PhysRevLett.110.155301], we investigate what quantum phases can be created in these systems in one dimension. We consider a geometry of two coupled one-dimensional (1D) systems, and derive the quantum phase diagram of ultracold fermionic atoms interacting via quadrupole-quadrupole interactions within a Tomonaga-Luttinger-liquid framework. We map out the phase diagram as a function of the distance between the two tubes and the angle between the direction of the tubes and the quadrupolar moments. The latter can be controlled by an external field. We show that there are two magic angles θB,1c and θB,2c between 0 and π /2, where the intratube quadrupolar interactions vanish and change signs. Adopting a pseudospin language with regard to the two 1D systems, the system undergoes a spin-gap transition and displays a zigzag density pattern, above θB,2c and below θB,1c. Between the two magic angles, we show that polarized triplet superfluidity and a planar spin-density-wave order compete with each other. The latter corresponds to a bond-order solid in higher dimensions. We demonstrate that this order can be further stabilized by applying a commensurate periodic potential along the tubes.

Metabolomics of Breast Cancer Using High-Resolution Magic Angle Spinning Magnetic Resonance Spectroscopy: Correlations with 18F-FDG Positron Emission Tomography-Computed Tomography, Dynamic Contrast-Enhanced and Diffusion-Weighted Imaging MRI.

PubMed

Yoon, Haesung; Yoon, Dahye; Yun, Mijin; Choi, Ji Soo; Park, Vivian Youngjean; Kim, Eun-Kyung; Jeong, Joon; Koo, Ja Seung; Yoon, Jung Hyun; Moon, Hee Jung; Kim, Suhkmann; Kim, Min Jung

2016-01-01

Our goal in this study was to find correlations between breast cancer metabolites and conventional quantitative imaging parameters using high-resolution magic angle spinning (HR-MAS) magnetic resonance spectroscopy (MRS) and to find breast cancer subgroups that show high correlations between metabolites and imaging parameters. Between August 2010 and December 2013, we included 53 female patients (mean age 49.6 years; age range 32-75 years) with a total of 53 breast lesions assessed by the Breast Imaging Reporting and Data System. They were enrolled under the following criteria: breast lesions larger than 1 cm in diameter which 1) were suspicious for malignancy on mammography or ultrasound (US), 2) were pathologically confirmed to be breast cancer with US-guided core-needle biopsy (CNB) 3) underwent 3 Tesla MRI with dynamic contrast-enhanced (DCE) and diffusion-weighted imaging (DWI) and positron emission tomography-computed tomography (PET-CT), and 4) had an attainable immunohistochemistry profile from CNB. We acquired spectral data by HR-MAS MRS with CNB specimens and expressed the data as relative metabolite concentrations. We compared the metabolites with the signal enhancement ratio (SER), maximum standardized FDG uptake value (SUV max), apparent diffusion coefficient (ADC), and histopathologic prognostic factors for correlation. We calculated Spearman correlations and performed a partial least squares-discriminant analysis (PLS-DA) to further classify patient groups into subgroups to find correlation differences between HR-MAS spectroscopic values and conventional imaging parameters. In a multivariate analysis, the PLS-DA models built with HR-MAS MRS metabolic profiles showed visible discrimination between high and low SER, SUV, and ADC. In luminal subtype breast cancer, compared to all cases, high SER, ADV, and SUV were more closely clustered by visual assessment. Multiple metabolites were correlated with SER and SUV in all cases. Multiple metabolites showed correlations with SER and SUV in the ER positive, HER2 negative, and Ki-67 negative groups. High levels of PC, choline, and glycine acquired from HR-MAS MRS using CNB specimens were noted in the high SER group via DCE MRI and the high SUV group via PET-CT, with significant correlations between choline and SER and between PC and SUV. Further studies should investigate whether HR-MAS MRS using CNB specimens can provide similar or more prognostic information than conventional quantitative imaging parameters.

Liquid- and solid-state high-resolution NMR methods for the investigation of aging processes of silicone breast implants.

PubMed

Birkefeld, Anja Britta; Bertermann, Rüdiger; Eckert, Hellmut; Pfleiderer, Bettina

2003-01-01

To investigate aging processes of silicone gel breast implants, which may include migration of free unreacted material from the gel and rubber to local (e.g. connective tissue capsule) or distant sites in the body, chemical alteration of the polymer and infiltration of body compounds, various approaches of multinuclear nuclear magnetic resonance (NMR) experiments (29Si, 13C, 1H) were evaluated. While 29Si, 13C, and 1H solid-state magic angle spinning (MAS) NMR techniques performed on virgin and explanted envelopes of silicone prostheses provided only limited information, high-resolution liquid-state NMR techniques of CDCl(3) extracts were highly sensitive analytical tools for the detection of aging related changes in the materials. Using 2D 1H, 1H correlation spectroscopy (COSY) and 29Si, 1H heteronuclear multiple bond coherence (HMBC) experiments with gradient selection, it was possible to detect lipids (mainly phospholipids) as well as silicone oligomer species in explanted envelopes and gels. Silicone oligomers were also found in connective tissue capsules, indicating that cyclic polysiloxanes can migrate from intact implants to adjacent and distant sites. Furthermore, lipids can permeate the implant and modify its chemical composition. Copyright 2002 Elsevier Science Ltd.

1H-detected MAS solid-state NMR experiments enable the simultaneous mapping of rigid and dynamic domains of membrane proteins

NASA Astrophysics Data System (ADS)

Gopinath, T.; Nelson, Sarah E. D.; Veglia, Gianluigi

2017-12-01

Magic angle spinning (MAS) solid-state NMR (ssNMR) spectroscopy is emerging as a unique method for the atomic resolution structure determination of native membrane proteins in lipid bilayers. Although 13C-detected ssNMR experiments continue to play a major role, recent technological developments have made it possible to carry out 1H-detected experiments, boosting both sensitivity and resolution. Here, we describe a new set of 1H-detected hybrid pulse sequences that combine through-bond and through-space correlation elements into single experiments, enabling the simultaneous detection of rigid and dynamic domains of membrane proteins. As proof-of-principle, we applied these new pulse sequences to the membrane protein phospholamban (PLN) reconstituted in lipid bilayers under moderate MAS conditions. The cross-polarization (CP) based elements enabled the detection of the relatively immobile residues of PLN in the transmembrane domain using through-space correlations; whereas the most dynamic region, which is in equilibrium between folded and unfolded states, was mapped by through-bond INEPT-based elements. These new 1H-detected experiments will enable one to detect not only the most populated (ground) states of biomacromolecules, but also sparsely populated high-energy (excited) states for a complete characterization of protein free energy landscapes.

NMR of thin layers using a meanderline surface coil

DOEpatents

Cowgill, Donald F.

2001-01-01

A miniature meanderline sensor coil which extends the capabilities of nuclear magnetic resonance (NMR) to provide analysis of thin planar samples and surface layer geometries. The sensor coil allows standard NMR techniques to be used to examine thin planar (or curved) layers, extending NMRs utility to many problems of modern interest. This technique can be used to examine contact layers, non-destructively depth profile into films, or image multiple layers in a 3-dimensional sense. It lends itself to high resolution NMR techniques of magic angle spinning and thus can be used to examine the bonding and electronic structure in layered materials or to observe the chemistry associated with aging coatings. Coupling this sensor coil technology with an arrangement of small magnets will produce a penetrator probe for remote in-situ chemical analysis of groundwater or contaminant sediments. Alternatively, the sensor coil can be further miniaturized to provide sub-micron depth resolution within thin films or to orthoscopically examine living tissue. This thin-layer NMR technique using a stationary meanderline coil in a series-resonant circuit has been demonstrated and it has been determined that the flat meanderline geometry has about he same detection sensitivity as a solenoidal coil, but is specifically tailored to examine planar material layers, while avoiding signals from the bulk.

Discerning the Location and Nature of Coke Deposition from Surface to Bulk of Spent Zeolite Catalysts

NASA Astrophysics Data System (ADS)

Devaraj, Arun; Vijayakumar, Murugesan; Bao, Jie; Guo, Mond F.; Derewinski, Miroslaw A.; Xu, Zhijie; Gray, Michel J.; Prodinger, Sebastian; Ramasamy, Karthikeyan K.

2016-11-01

The formation of carbonaceous deposits (coke) in zeolite pores during catalysis leads to temporary deactivation of catalyst, necessitating regeneration steps, affecting throughput, and resulting in partial permanent loss of catalytic efficiency. Yet, even to date, the coke molecule distribution is quite challenging to study with high spatial resolution from surface to bulk of the catalyst particles at a single particle level. To address this challenge we investigated the coke molecules in HZSM-5 catalyst after ethanol conversion treatment by a combination of C K-edge X-ray absorption spectroscopy (XAS), 13C Cross polarization-magic angle spinning nuclear magnetic resonance (CP-MAS NMR) spectroscopy, and atom probe tomography (APT). XAS and NMR highlighted the aromatic character of coke molecules. APT permitted the imaging of the spatial distribution of hydrocarbon molecules located within the pores of spent HZSM-5 catalyst from surface to bulk at a single particle level. 27Al NMR results and APT results indicated association of coke molecules with Al enriched regions within the spent HZSM-5 catalyst particles. The experimental results were additionally validated by a level-set-based APT field evaporation model. These results provide a new approach to investigate catalytic deactivation due to hydrocarbon coking or poisoning of zeolites at an unprecedented spatial resolution.

Discerning the Location and Nature of Coke Deposition from Surface to Bulk of Spent Zeolite Catalysts

PubMed Central

Devaraj, Arun; Vijayakumar, Murugesan; Bao, Jie; Guo, Mond F.; Derewinski, Miroslaw A.; Xu, Zhijie; Gray, Michel J.; Prodinger, Sebastian; Ramasamy, Karthikeyan K.

2016-01-01

The formation of carbonaceous deposits (coke) in zeolite pores during catalysis leads to temporary deactivation of catalyst, necessitating regeneration steps, affecting throughput, and resulting in partial permanent loss of catalytic efficiency. Yet, even to date, the coke molecule distribution is quite challenging to study with high spatial resolution from surface to bulk of the catalyst particles at a single particle level. To address this challenge we investigated the coke molecules in HZSM-5 catalyst after ethanol conversion treatment by a combination of C K-edge X-ray absorption spectroscopy (XAS), 13C Cross polarization-magic angle spinning nuclear magnetic resonance (CP-MAS NMR) spectroscopy, and atom probe tomography (APT). XAS and NMR highlighted the aromatic character of coke molecules. APT permitted the imaging of the spatial distribution of hydrocarbon molecules located within the pores of spent HZSM-5 catalyst from surface to bulk at a single particle level. 27Al NMR results and APT results indicated association of coke molecules with Al enriched regions within the spent HZSM-5 catalyst particles. The experimental results were additionally validated by a level-set–based APT field evaporation model. These results provide a new approach to investigate catalytic deactivation due to hydrocarbon coking or poisoning of zeolites at an unprecedented spatial resolution. PMID:27876869

Radiological properties of MAGIC normoxic polymer gel dosimetry

NASA Astrophysics Data System (ADS)

Aljamal, M.; Zakaria, A.; Shamsuddin, S.

2013-04-01

For a polymer gel dosimeter to be of use in radiation dosimetry, it should display water-equivalent radiological properties. In this study, the radiological properties of the MAGIC (Methacrylic and Ascorbic acid in Gelatin Initiated by Copper) normoxic polymer gels were investigated. The mass density (ρ) was determined based on Archimedes' principle. The weight fraction of elemental composition and the effective atomic number (Zeff) were calculated. The electron density was also measured with 90° scattering angle at room temperature. The linear attenuation coefficient (μ) of unirradiated gel, irradiated gel, and water were determined using Am-241 based on narrow beam geometry. Monte Carlo simulation was used to calculate the depth doses response of MAGIC gel and water for 6MV photon beam. The weight fractions of elements composition of MAGIC gel were close to that for water. The mass density was found to be 1027 ± 2 kg m-3, which is also very close to mass density of muscle tissue (1030 kg m-3) and 2.7% higher than that of water. The electron density (ρe) and atomic number (Zeff) were found to be 3.43 × 1029 e m-3 and 7.105, respectively. The electron density measured was 2.6% greater than that for water. The atomic number was very close to that for water. The prepared MAGIC gel was found to be water equivalent based on the study of element composition, mass density, electron density and atomic number. The linear attenuation coefficient of unirradiated gel was very close to that of water. The μ of irradiated gel was found to be linear with dose 2-40 Gy. The depth dose response for MAGIC gel from a 6 MV photon beam had a percentage dose difference to water of less than 1%. Therefore it satisfies the criteria to be a good polymer gel dosimeter for radiotherapy.

Spin dynamics in the modulation frame: application to homonuclear recoupling in magic angle spinning solid-state NMR.

PubMed

De Paëpe, Gaël; Lewandowski, Józef R; Griffin, Robert G

2008-03-28

We introduce a family of solid-state NMR pulse sequences that generalizes the concept of second averaging in the modulation frame and therefore provides a new approach to perform magic angle spinning dipolar recoupling experiments. Here, we focus on two particular recoupling mechanisms-cosine modulated rotary resonance (CMpRR) and cosine modulated recoupling with isotropic chemical shift reintroduction (COMICS). The first technique, CMpRR, is based on a cosine modulation of the rf phase and yields broadband double-quantum (DQ) (13)C recoupling using >70 kHz omega(1,C)/2pi rf field for the spinning frequency omega(r)/2=10-30 kHz and (1)H Larmor frequency omega(0,H)/2pi up to 900 MHz. Importantly, for p>or=5, CMpRR recouples efficiently in the absence of (1)H decoupling. Extension to lower p values (3.5

Characterization of lithium coordination sites with magic-angle spinning NMR

NASA Astrophysics Data System (ADS)

Haimovich, A.; Goldbourt, A.

2015-05-01

Lithium, in the form of lithium carbonate, is one of the most common drugs for bipolar disorder. Lithium is also considered to have an effect on many other cellular processes hence it possesses additional therapeutic as well as side effects. In order to quantitatively characterize the binding mode of lithium, it is required to identify the interacting species and measure their distances from the metal center. Here we use magic-angle spinning (MAS) solid-state NMR to study the binding site of lithium in complex with glycine and water (LiGlyW). Such a compound is a good enzyme mimetic since lithium is four-coordinated to one water molecule and three carboxylic groups. Distance measurements to carbons are performed using a 2D transferred echo double resonance (TEDOR) MAS solid-state NMR experiment, and water binding is probed by heteronuclear high-resolution proton-lithium and proton-carbon correlation (wPMLG-HETCOR) experiments. Both HETCOR experiments separate the main complex from impurities and non-specifically bound lithium species, demonstrating the sensitivity of the method to probe the species in the binding site. Optimizations of the TEDOR pulse scheme in the case of a quadrupolar nucleus with a small quadrupole coupling constant show that it is most efficient when pulses are positioned on the spin-1/2 (carbon-13) nucleus. Since the intensity of the TEDOR signal is not normalized, careful data analysis that considers both intensity and dipolar oscillations has to be performed. Nevertheless we show that accurate distances can be extracted for both carbons of the bound glycine and that these distances are consistent with the X-ray data and with lithium in a tetrahedral environment. The lithium environment in the complex is very similar to the binding site in inositol monophosphatase, an enzyme associated with bipolar disorder and the putative target for lithium therapy. A 2D TEDOR experiment applied to the bacterial SuhB gene product of this enzyme was designed to probe direct correlations between lithium, the enzyme inhibitor, and the closest carboxyl carbons of the binding site. At this point, the chemical shift of the bound carboxyl groups in this 29 kDa enzyme could be determined.

Investigation of metabolite changes in the transition from pre-invasive to invasive cervical cancer measured using (1)H and (31)P magic angle spinning MRS of intact tissue.

PubMed

De Silva, Sonali S; Payne, Geoffrey S; Thomas, Valerie; Carter, Paul G; Ind, Thomas E J; deSouza, Nandita M

2009-02-01

The aim of this study was to determine the metabolic changes in the transition from pre-invasive to invasive cervical cancer using high-resolution magic angle spinning (HR-MAS) MRS. Biopsy specimens were obtained from women with histologically normal cervix (n = 5), cervical intraepithelial neoplasia (CIN; mild, n = 5; moderate/severe, n = 40), and invasive cancer (n = 23). (1)H HR-MAS MRS data were acquired using a Bruker Avance 11.74 T spectrometer (Carr-Purcell-Meiboom-Gill sequence; TR = 4.8 s; TE = 135 ms; 512 scans; 41 min acquisition). (31)P HR-MAS spectra were obtained from the normal subjects and cancer patients only (as acetic acid applied before tissue sampling in patients with CIN impaired spectral quality) using a (1)H-decoupled pulse-acquire sequence (TR = 2.82 s; 2048 scans; 96 min acquisition). Peak assignments were based on values reported in the literature. Peak areas were measured using the AMARES algorithm. Estimated metabolite concentrations were compared between patient diagnostic categories and tissue histology using independent samples t tests. Comparisons based on patient category at diagnosis showed significantly higher estimated concentrations of choline (P = 0.0001) and phosphocholine (P = 0.002) in tissue from patients with cancer than from patients with high-grade dyskaryosis, but no differences between non-cancer groups. Division by histology of the sample also showed increases in choline (P = 0.002) and phosphocholine (P = 0.002) in cancer compared with high-grade CIN tissue. Phosphoethanolamine was increased in cancer compared with normal tissue (P = 0.0001). Estimated concentrations of alanine (P = 0.01) and creatine (P = 0.008) were significantly reduced in normal tissue from cancer patients compared with normal tissue from non-cancer patients. The estimated concentration of choline was significantly increased in CIN tissue from cancer patients compared with CIN tissue from non-cancer patients (P = 0.0001). Estimated concentrations of choline-containing metabolites increased from pre-invasive to invasive cervical cancer. Concurrent metabolite depletion occurs in normal tissue adjacent to cancer tissue. Copyright (c) 2008 John Wiley & Sons, Ltd.

Structural characterisation of the Li argyrodites Li7PS6 and Li7PSe6 and their solid solutions: quantification of site preferences by MAS-NMR spectroscopy.

PubMed

Kong, Shiao Tong; Gün, Ozgül; Koch, Barbara; Deiseroth, Hans Jörg; Eckert, Hellmut; Reiner, Christof

2010-05-03

Li(7)PS(6) and Li(7)PSe(6) belong to a class of new solids that exhibit high Li(+) mobility. A series of quaternary solid solutions Li(7)PS(6-x)Se(x) (0 < or = x < or = 6) were characterised by X-ray crystallography and magic-angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy. The high-temperature (HT) modifications were studied by single-crystal investigations (both F43m, Z=4, Li(7)PS(6): a=9.993(1) A, Li(7)PSe(6): a=10.475(1) A) and show the typical argyrodite structures with strongly disordered Li atoms. HT-Li(7)PS(6) and HT-Li(7)PSe(6) transform reversibly into low-temperature (LT) modifications with ordered Li atoms. X-ray powder diagrams show the structures of LT-Li(7)PS(6) and LT-Li(7)PSe(6) to be closely related to orthorhombic LT-alpha-Cu(7)PSe(6). Single crystals of the LT modifications are not available due to multiple twinning and formation of antiphase domains. The gradual substitution of S by Se shows characteristic site preferences closely connected to the functionalities of the different types of chalcogen atoms (S, Se). High-resolution solid-state (31)P NMR is a powerful method to differentiate quantitatively between the distinct (PS(4-n)Se(n))(3-) local environments. Their population distribution differs significantly from a statistical scenario, revealing a pronounced preference for P-S over P-Se bonding. This preference, shown for the series of LT samples, can be quantified in terms of an equilibrium constant specifying the melt reaction Se(P)+S(2-) <==>S(P)+Se(2-), prior to crystallisation. The (77)Se MAS-NMR spectra reveal that the chalcogen distributions in the second and third coordination sphere of the P atoms are essentially statistical. The number of crystallographically independent Li atoms in both LT modifications was analysed by means of (6)Li{(7)Li} cross polarisation magic angle spinning (CPMAS).

Site-resolved multiple-quantum filtered correlations and distance measurements by magic-angle spinning NMR: Theory and applications to spins with weak to vanishing quadrupolar couplings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eliav, U., E-mail: amirgo@tau.ac.il, E-mail: eliav@tau.ac.il; Haimovich, A.; Goldbourt, A., E-mail: amirgo@tau.ac.il, E-mail: eliav@tau.ac.il

2016-01-14

We discuss and analyze four magic-angle spinning solid-state NMR methods that can be used to measure internuclear distances and to obtain correlation spectra between a spin I = 1/2 and a half-integer spin S > 1/2 having a small quadrupolar coupling constant. Three of the methods are based on the heteronuclear multiple-quantum and single-quantum correlation experiments, that is, high rank tensors that involve the half spin and the quadrupolar spin are generated. Here, both zero and single-quantum coherence of the half spins are allowed and various coherence orders of the quadrupolar spin are generated, and filtered, via active recoupling ofmore » the dipolar interaction. As a result of generating coherence orders larger than one, the spectral resolution for the quadrupolar nucleus increases linearly with the coherence order. Since the formation of high rank tensors is independent of the existence of a finite quadrupolar interaction, these experiments are also suitable to materials in which there is high symmetry around the quadrupolar spin. A fourth experiment is based on the initial quadrupolar-driven excitation of symmetric high order coherences (up to p = 2S, where S is the spin number) and subsequently generating by the heteronuclear dipolar interaction higher rank (l + 1 or higher) tensors that involve also the half spins. Due to the nature of this technique, it also provides information on the relative orientations of the quadrupolar and dipolar interaction tensors. For the ideal case in which the pulses are sufficiently strong with respect to other interactions, we derive analytical expressions for all experiments as well as for the transferred echo double resonance experiment involving a quadrupolar spin. We show by comparison of the fitting of simulations and the analytical expressions to experimental data that the analytical expressions are sufficiently accurate to provide experimental {sup 7}Li–{sup 13}C distances in a complex of lithium, glycine, and water. Discussion of the regime for which such an approach is valid is given.« less

Q(n) species distribution in K2O.2SiO2 glass by 29Si magic angle flipping NMR.

PubMed

Davis, Michael C; Kaseman, Derrick C; Parvani, Sahar M; Sanders, Kevin J; Grandinetti, Philip J; Massiot, Dominique; Florian, Pierre

2010-05-06

Two-dimensional magic angle flipping (MAF) was employed to measure the Q((n)) distribution in a (29)Si-enriched potassium disilicate glass (K(2)O.2SiO(2)). Relative concentrations of [Q((4))] = 7.2 +/- 0.3%, [Q((3))] = 82.9 +/- 0.1%, and [Q((2))] = 9.8 +/- 0.6% were obtained. Using the thermodynamic model for Q((n)) species disproportionation, these relative concentrations yield an equilibrium constant k(3) = 0.0103 +/- 0.0008, indicating, as expected, that the Q((n)) species distribution is close to binary in the potassium disilicate glass. A Gaussian distribution of isotropic chemical shifts was observed for each Q((n)) species with mean values of -82.74 +/- 0.03, -91.32 +/- 0.01, and -101.67 +/- 0.02 ppm and standard deviations of 3.27 +/- 0.03, 4.19 +/- 0.01, and 5.09 +/- 0.03 ppm for Q((2)), Q((3)), and Q((4)), respectively. Additionally, nuclear shielding anisotropy values of zeta =-85.0 +/- 1.3 ppm, eta = 0.48 +/- 0.02 for Q((2)) and zeta = -74.9 +/- 0.2 ppm, eta = 0.03 +/- 0.01 for Q((3)) were observed in the potassium disilicate glass.

Recoupling of Heteronuclear Dipolar Interactions with Rotational-Echo Double-Resonance at High Magic-Angle Spinning Frequencies

NASA Astrophysics Data System (ADS)

Jaroniec, Christopher P.; Tounge, Brett A.; Rienstra, Chad M.; Herzfeld, Judith; Griffin, Robert G.

2000-09-01

Heteronuclear dipolar recoupling with rotational-echo double-resonance (REDOR) is investigated in the rapid magic-angle spinning regime, where radiofrequency irradiation occupies a significant fraction of the rotor period (10-60%). We demonstrate, in two model 13C-15N spin systems, [1-13C, 15N] and [2-13C, 15N]glycine, that REDOR ΔS/S0 curves acquired at high MAS rates and relatively low recoupling fields are nearly identical to the ΔS/S0 curve expected for REDOR with ideal δ-function pulses. The only noticeable effect of the finite π pulse length on the recoupling is a minor scaling of the dipolar oscillation frequency. Experimental results are explained using both numerical calculations and average Hamiltonian theory, which is used to derive analytical expressions for evolution under REDOR recoupling sequences with different π pulse phasing schemes. For xy-4 and extensions thereof, finite pulses scale only the dipolar oscillation frequency by a well-defined factor. For other phasing schemes (e.g., xx-4 and xx¯-4) both the frequency and amplitude of the oscillation are expected to change.

Mechanism studies of the conversion of 13C-labeled n-butane on zeolite H-ZSM-5 by using 13C magic angle spinning NMR spectroscopy and GC-MS analysis.

PubMed

Luzgin, Mikhail V; Stepanov, Alexander G; Arzumanov, Sergei S; Rogov, Vladimir A; Parmon, Valentin N; Wang, Wei; Hunger, Michael; Freude, Dieter

2005-12-23

By using 13C MAS NMR spectroscopy (MAS = magic angle spinning), the conversion of selectively 13C-labeled n-butane on zeolite H-ZSM-5 at 430-470 K has been demonstrated to proceed through two pathways: 1) scrambling of the selective 13C-label in the n-butane molecule, and 2) oligomerization-cracking and conjunct polymerization. The latter processes (2) produce isobutane and propane simultaneously with alkyl-substituted cyclopentenyl cations and condensed aromatic compounds. In situ 13C MAS NMR and complementary ex situ GC-MS data provided evidence for a monomolecular mechanism of the 13C-label scrambling, whereas both isobutane and propane are formed through intermolecular pathways. According to 13C MAS NMR kinetic measurements, both pathways proceed with nearly the same activation energies (E(a) = 75 kJ mol(-1) for the scrambling and 71 kJ mol(-1) for isobutane and propane formation). This can be rationalized by considering the intermolecular hydride transfer between a primarily initiated carbenium ion and n-butane as being the rate-determining stage of the n-butane conversion on zeolite H-ZSM-5.

A permanent MRI magnet for magic angle imaging having its field parallel to the poles.

PubMed

McGinley, John V M; Ristic, Mihailo; Young, Ian R

2016-10-01

A novel design of open permanent magnet is presented, in which the magnetic field is oriented parallel to the planes of its poles. The paper describes the methods whereby such a magnet can be designed with a field homogeneity suitable for Magnetic Resonance Imaging (MRI). Its primary purpose is to take advantage of the Magic Angle effect in MRI of human extremities, particularly the knee joint, by being capable of rotating the direction of the main magnetic field B0 about two orthogonal axes around a stationary subject and achieve all possible angulations. The magnet comprises a parallel pair of identical profiled arrays of permanent magnets backed by a flat steel yoke such that access in lateral directions is practical. The paper describes the detailed optimization procedure from a target 150mm DSV to the achievement of a measured uniform field over a 130mm DSV. Actual performance data of the manufactured magnet, including shimming and a sample image, is presented. The overall magnet system mounting mechanism is presented, including two orthogonal axes of rotation of the magnet about its isocentre. Copyright © 2016 Elsevier Inc. All rights reserved.

Sensitivity enhancement by multiple-contact cross-polarization under magic-angle spinning.

PubMed

Raya, J; Hirschinger, J

2017-08-01

Multiple-contact cross-polarization (MC-CP) is applied to powder samples of ferrocene and l-alanine under magic-angle spinning (MAS) conditions. The method is described analytically through the density matrix formalism. The combination of a two-step memory function approach and the Anderson-Weiss approximation is found to be particularly useful to derive approximate analytical solutions for single-contact Hartmann-Hahn CP (HHCP) and MC-CP dynamics under MAS. We show that the MC-CP sequence requiring no pulse-shape optimization yields higher polarizations at short contact times than optimized adiabatic passage through the HH condition CP (APHH-CP) when the MAS frequency is comparable to the heteronuclear dipolar coupling, i.e., when APHH-CP through a single sideband matching condition is impossible or difficult to perform. It is also shown that the MC-CP sideband HH conditions are generally much broader than for single-contact HHCP and that efficient polarization transfer at the centerband HH condition can be reintroduced by rotor-asynchronous multiple equilibrations-re-equilibrations with the proton spin bath. Boundary conditions for the successful use of the MC-CP experiment when relying on spin-lattice relaxation for repolarization are also examined. Copyright © 2017 Elsevier Inc. All rights reserved.

The NMR-Rosetta capsid model of M13 bacteriophage reveals a quadrupled hydrophobic packing epitope.

PubMed

Morag, Omry; Sgourakis, Nikolaos G; Baker, David; Goldbourt, Amir

2015-01-27

Filamentous phage are elongated semiflexible ssDNA viruses that infect bacteria. The M13 phage, belonging to the family inoviridae, has a length of ∼1 μm and a diameter of ∼7 nm. Here we present a structural model for the capsid of intact M13 bacteriophage using Rosetta model building guided by structure restraints obtained from magic-angle spinning solid-state NMR experimental data. The C5 subunit symmetry observed in fiber diffraction studies was enforced during model building. The structure consists of stacked pentamers with largely alpha helical subunits containing an N-terminal type II β-turn; there is a rise of 16.6-16.7 Å and a tilt of 36.1-36.6° between consecutive pentamers. The packing of the subunits is stabilized by a repeating hydrophobic stacking pocket; each subunit participates in four pockets by contributing different hydrophobic residues, which are spread along the subunit sequence. Our study provides, to our knowledge, the first magic-angle spinning NMR structure of an intact filamentous virus capsid and further demonstrates the strength of this technique as a method of choice to study noncrystalline, high-molecular-weight molecular assemblies.

The NMR–Rosetta capsid model of M13 bacteriophage reveals a quadrupled hydrophobic packing epitope

PubMed Central

Morag, Omry; Sgourakis, Nikolaos G.; Baker, David; Goldbourt, Amir

2015-01-01

Filamentous phage are elongated semiflexible ssDNA viruses that infect bacteria. The M13 phage, belonging to the family inoviridae, has a length of ∼1 μm and a diameter of ∼7 nm. Here we present a structural model for the capsid of intact M13 bacteriophage using Rosetta model building guided by structure restraints obtained from magic-angle spinning solid-state NMR experimental data. The C5 subunit symmetry observed in fiber diffraction studies was enforced during model building. The structure consists of stacked pentamers with largely alpha helical subunits containing an N-terminal type II β-turn; there is a rise of 16.6–16.7 Å and a tilt of 36.1–36.6° between consecutive pentamers. The packing of the subunits is stabilized by a repeating hydrophobic stacking pocket; each subunit participates in four pockets by contributing different hydrophobic residues, which are spread along the subunit sequence. Our study provides, to our knowledge, the first magic-angle spinning NMR structure of an intact filamentous virus capsid and further demonstrates the strength of this technique as a method of choice to study noncrystalline, high-molecular-weight molecular assemblies. PMID:25587134

Low-temperature dynamic nuclear polarization with helium-cooled samples and nitrogen-driven magic-angle spinning.

PubMed

Thurber, Kent; Tycko, Robert

2016-03-01

We describe novel instrumentation for low-temperature solid state nuclear magnetic resonance (NMR) with dynamic nuclear polarization (DNP) and magic-angle spinning (MAS), focusing on aspects of this instrumentation that have not been described in detail in previous publications. We characterize the performance of an extended interaction oscillator (EIO) microwave source, operating near 264 GHz with 1.5 W output power, which we use in conjunction with a quasi-optical microwave polarizing system and a MAS NMR probe that employs liquid helium for sample cooling and nitrogen gas for sample spinning. Enhancement factors for cross-polarized (13)C NMR signals in the 100-200 range are demonstrated with DNP at 25K. The dependences of signal amplitudes on sample temperature, as well as microwave power, polarization, and frequency, are presented. We show that sample temperatures below 30K can be achieved with helium consumption rates below 1.3 l/h. To illustrate potential applications of this instrumentation in structural studies of biochemical systems, we compare results from low-temperature DNP experiments on a calmodulin-binding peptide in its free and bound states. Published by Elsevier Inc.

Simultaneous acquisition of 2D and 3D solid-state NMR experiments for sequential assignment of oriented membrane protein samples.

PubMed

Gopinath, T; Mote, Kaustubh R; Veglia, Gianluigi

2015-05-01

We present a new method called DAISY (Dual Acquisition orIented ssNMR spectroScopY) for the simultaneous acquisition of 2D and 3D oriented solid-state NMR experiments for membrane proteins reconstituted in mechanically or magnetically aligned lipid bilayers. DAISY utilizes dual acquisition of sine and cosine dipolar or chemical shift coherences and long living (15)N longitudinal polarization to obtain two multi-dimensional spectra, simultaneously. In these new experiments, the first acquisition gives the polarization inversion spin exchange at the magic angle (PISEMA) or heteronuclear correlation (HETCOR) spectra, the second acquisition gives PISEMA-mixing or HETCOR-mixing spectra, where the mixing element enables inter-residue correlations through (15)N-(15)N homonuclear polarization transfer. The analysis of the two 2D spectra (first and second acquisitions) enables one to distinguish (15)N-(15)N inter-residue correlations for sequential assignment of membrane proteins. DAISY can be implemented in 3D experiments that include the polarization inversion spin exchange at magic angle via I spin coherence (PISEMAI) sequence, as we show for the simultaneous acquisition of 3D PISEMAI-HETCOR and 3D PISEMAI-HETCOR-mixing experiments.

Nuclear relaxation and critical fluctuations in membranes containing cholesterol

NASA Astrophysics Data System (ADS)

McConnell, Harden

2009-04-01

Nuclear resonance frequencies in bilayer membranes depend on lipid composition. Our calculations describe the combined effects of composition fluctuations and diffusion on nuclear relaxation near a miscibility critical point. Both tracer and gradient diffusion are included. The calculations involve correlation functions and a correlation length ξ =ξ0T/(T -Tc), where T -Tc is temperature above the critical temperature and ξ0 is a parameter of molecular length. Several correlation functions are examined, each of which is related in some degree to the Ising model correlation function. These correlation functions are used in the calculation of transverse deuterium relaxation rates in magic angle spinning and quadrupole echo experiments. The calculations are compared with experiments that report maxima in deuterium and proton nuclear relaxation rates at the critical temperature [Veatch et al., Proc. Nat. Acad. Sci. U.S.A. 104, 17650 (2007)]. One Ising-model-related correlation function yields a maximum 1/T2 relaxation rate at the critical temperature for both magic angle spinning and quadrupole echo experiments. The calculated rates at the critical temperature are close to the experimental rates. The rate maxima involve relatively rapid tracer diffusion in a static composition gradient over distances of up to 10-100 nm.

Sensitivity enhancement by multiple-contact cross-polarization under magic-angle spinning

NASA Astrophysics Data System (ADS)

Raya, J.; Hirschinger, J.

2017-08-01

Multiple-contact cross-polarization (MC-CP) is applied to powder samples of ferrocene and L-alanine under magic-angle spinning (MAS) conditions. The method is described analytically through the density matrix formalism. The combination of a two-step memory function approach and the Anderson-Weiss approximation is found to be particularly useful to derive approximate analytical solutions for single-contact Hartmann-Hahn CP (HHCP) and MC-CP dynamics under MAS. We show that the MC-CP sequence requiring no pulse-shape optimization yields higher polarizations at short contact times than optimized adiabatic passage through the HH condition CP (APHH-CP) when the MAS frequency is comparable to the heteronuclear dipolar coupling, i.e., when APHH-CP through a single sideband matching condition is impossible or difficult to perform. It is also shown that the MC-CP sideband HH conditions are generally much broader than for single-contact HHCP and that efficient polarization transfer at the centerband HH condition can be reintroduced by rotor-asynchronous multiple equilibrations-re-equilibrations with the proton spin bath. Boundary conditions for the successful use of the MC-CP experiment when relying on spin-lattice relaxation for repolarization are also examined.

The chemical and dynamical influence of the anti-viral drug amantadine on the M2 proton channel transmembrane domain.

PubMed

Hu, Jun; Fu, Riqiang; Cross, Timothy A

2007-07-01

The M(2) proton channel plays a vital role in the life cycle of the influenza A virus. His(37), the key residue in the M(2) transmembrane domain (M(2)-TMD), plays a central role in the proton conductance mechanism. The anti-influenza drug, amantadine, inhibits the channel activity through binding to the pore of the M(2) channel. The nuclear spin relaxation data and polarization inversion spin exchange at the magic angle spectra show that both the polypeptide backbone and His(37) side chain are more constrained in the presence of amantadine. Using (15)N cross polarization magic-angle spinning NMR spectroscopy, the protonation of His(37) of M(2)-TMD in lipid bilayers was monitored in the absence and presence of amantadine as a function of pH. Binding amantadine lowers the His(37) pK(a) values by approximately three orders of magnitude compared with the first pK(a) of histidine in amantadine-free M(2)-TMD. Amantadine's influence on the His(37) chemical properties suggests a novel mechanism by which amantadine may inhibit proton conductance.

Measurement and interpretation of electron angle at MABE beam stop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanford, T.W.L.; Coleman, P.D.; Poukey, J.W.

1985-02-01

The mean angle of incidence at the beam stop of a 60 kA, 7 MV annular electron beam, in the 20 kG guide field of the MABE accelerator, is determined. Radiation dose measured in TLD arrays mounted downstream of the stop is compared with the radiation dose expected using a CYLTRAN Monte Carlo simulation of the electron/photon transport in the stop as a function of incident angles and energies. All radiation profiles measured are well fit, if the electrons are assumed to be incident with a polar angle theta of 15/sup 0/ +- 2/sup 0/. Comparing this theta with thatmore » expected from the Adler-Miller model, and a MAGIC code simulation of beam behavior at the stop enables the mean transverse beam velocity to be estimated.« less

Diamond-anvil cell for radial x-ray diffraction.

PubMed

Chesnut, G N; Schiferl, D; Streetman, B D; Anderson, W W

2006-06-28

We have designed a new diamond-anvil cell capable of radial x-ray diffraction to pressures of a few hundred GPa. The diffraction geometry allows access to multiple angles of Ψ, which is the angle between each reciprocal lattice vector g(hkl) and the compression axis of the cell. At the 'magic angle', Ψ≈54.7°, the effects of deviatoric stresses on the interplanar spacings, d(hkl), are significantly reduced. Because the systematic errors, which are different for each d(hkl), are significantly reduced, the crystal structures and the derived equations of state can be determined reliably. At other values of Ψ, the effects of deviatoric stresses on the diffraction pattern could eventually be used to determine elastic constants.

Unconventional superconductivity in magic-angle graphene superlattices.

PubMed

Cao, Yuan; Fatemi, Valla; Fang, Shiang; Watanabe, Kenji; Taniguchi, Takashi; Kaxiras, Efthimios; Jarillo-Herrero, Pablo

2018-04-05

The behaviour of strongly correlated materials, and in particular unconventional superconductors, has been studied extensively for decades, but is still not well understood. This lack of theoretical understanding has motivated the development of experimental techniques for studying such behaviour, such as using ultracold atom lattices to simulate quantum materials. Here we report the realization of intrinsic unconventional superconductivity-which cannot be explained by weak electron-phonon interactions-in a two-dimensional superlattice created by stacking two sheets of graphene that are twisted relative to each other by a small angle. For twist angles of about 1.1°-the first 'magic' angle-the electronic band structure of this 'twisted bilayer graphene' exhibits flat bands near zero Fermi energy, resulting in correlated insulating states at half-filling. Upon electrostatic doping of the material away from these correlated insulating states, we observe tunable zero-resistance states with a critical temperature of up to 1.7 kelvin. The temperature-carrier-density phase diagram of twisted bilayer graphene is similar to that of copper oxides (or cuprates), and includes dome-shaped regions that correspond to superconductivity. Moreover, quantum oscillations in the longitudinal resistance of the material indicate the presence of small Fermi surfaces near the correlated insulating states, in analogy with underdoped cuprates. The relatively high superconducting critical temperature of twisted bilayer graphene, given such a small Fermi surface (which corresponds to a carrier density of about 10 11 per square centimetre), puts it among the superconductors with the strongest pairing strength between electrons. Twisted bilayer graphene is a precisely tunable, purely carbon-based, two-dimensional superconductor. It is therefore an ideal material for investigations of strongly correlated phenomena, which could lead to insights into the physics of high-critical-temperature superconductors and quantum spin liquids.

Transforming White Light into Rainbows: Segmentation Strategies for Successful School Tax Elections

ERIC Educational Resources Information Center

Senden, J. Bradford; Lifto, Don E.

2009-01-01

In the late 1600s, British physicist Sir Isaac Newton first demonstrated refraction and dispersion in a triangular prism. He discovered that a prism could decompose white light into a spectrum. Hold a prism up to the light at the correct angle and white light magically splits into vivid colors of the rainbow! So what do prisms and rainbows have to…

Constraints on seismic anisotropy beneath the Appalachian Mountains from Love-to-Rayleigh wave scattering

NASA Astrophysics Data System (ADS)

Servali, A.; Long, M. D.; Benoit, M.

2017-12-01

The eastern margin of North America has been affected by a series of mountain building and rifting events that have likely shaped the deep structure of the lithosphere. Observations of seismic anisotropy can provide insight into lithospheric deformation associated with these past tectonic events, as well as into present-day patterns of mantle flow beneath the passive margin. Previous work on SKS splitting beneath eastern North America has revealed fast splitting directions parallel to the strike of the Appalachian orogen in the central and southern Appalachians. A major challenge to the interpretation of SKS splitting measurements, however, is the lack of vertical resolution; isolating anisotropic structures at different depths is therefore difficult. Complementary constraints on the depth distribution of anisotropy can be provided by surface waves. In this study, we analyze the scattering of Love wave energy to Rayleigh waves, which is generated via sharp lateral gradients in anisotropic structure along the ray path. The scattered phases, known as quasi-Love (QL) waves, exhibit amplitude behavior that depend on the strength of the anisotropic contrast as well as the angle between the propagation azimuth and the anisotropic symmetry axis. We analyze data collected by the dense MAGIC seismic array across the central Appalachians. We examine teleseismic earthquakes of magnitude 6.7 and greater over a range of backazimuths, and isolate surface waves at periods between 100 and 500 seconds. We compare the data to synthetic seismograms generated by the Princeton Global ShakeMovie initiative to identify anomalous QL arrivals. We find evidence significant QL arrivals at MAGIC stations, with amplitudes depending on propagation azimuth and station location. Preliminary results are consistent with a sharp lateral gradient in seismic anisotropy across the Appalachian Mountains in the depth range between 100-200 km.

HR-MAS NMR metabolomics of 'Swingle' citrumelo rootstock genetically modified to overproduce proline.

PubMed

de Oliveira, Caroline S; Carlos, Eduardo F; Vieira, Luiz G E; Lião, Luciano M; Alcantara, Glaucia B

2014-08-01

The accumulation of proline is a typical physiological response to abiotic stresses in higher plants. 'Swingle' citrumelo, an important rootstock for citrus production, has been modified with a mutated Δ(1)-pyrroline-5-carboxylate synthetase gene (VaP5CSF129A) linked to the cauliflower mosaic virus 35S promoter to induce the overproduction of free proline. This paper presents a comparative metabolomic study of nontransgenic versus transgenic 'Swingle' citrumelo plants with high endogenous proline. (1)H high-resolution magic angle spinning nuclear magnetic resonance spectroscopy and multivariate analysis showed significant differences in some metabolites between the nontransgenic and transgenic leaves and roots. The overproduction of proline has reduced the sucrose content in transgenic leaves, revealing a metabolic cost for these plants. In roots, the high level of free proline acts for the adjustment of cation-anion balance, causing the reduction of acetic acid content. The same sucrose level in roots indicates that they can be considered as sucrose sink. Similar behavior may be waited for fruits produced on transgenic rootstock. Copyright © 2014 John Wiley & Sons, Ltd.

A (1)H HR-MAS NMR-Based Metabolomic Study for Metabolic Characterization of Rice Grain from Various Oryza sativa L. Cultivars.

PubMed

Song, Eun-Hye; Kim, Hyun-Ju; Jeong, Jaesik; Chung, Hyun-Jung; Kim, Han-Yong; Bang, Eunjung; Hong, Young-Shick

2016-04-20

Rice grain metabolites are important for better understanding of the plant physiology of various rice cultivars and thus for developing rice cultivars aimed at providing diverse processed products. However, the variation of global metabolites in rice grains has rarely been explored. Here, we report the identification of intra- or intercellular metabolites in rice (Oryza sativa L.) grain powder using a (1)H high-resolution magic angle spinning (HR-MAS) NMR-based metabolomic approach. Compared with nonwaxy rice cultivars, marked accumulation of lipid metabolites such as fatty acids, phospholipids, and glycerophosphocholine in the grains of waxy rice cultivars demonstrated the distinct metabolic regulation and adaptation of each cultivar for effective growth during future germination, which may be reflected by high levels of glutamate, aspartate, asparagine, alanine, and sucrose. Therefore, this study provides important insights into the metabolic variations of diverse rice cultivars and their associations with environmental conditions and genetic backgrounds, with the aim of facilitating efficient development and the improvement of rice grain quality through inbreeding with genetic or chemical modification and mutation.

Structural and interaction parameters of thermosensitive native α-elastin biohybrid microgel

NASA Astrophysics Data System (ADS)

Balaceanu, Andreea; Singh, Smriti; Demco, Dan E.; Möller, Martin

2014-09-01

The structural and water interaction parameters for native, α-elastin biohybrid microgel crosslinked with hydrophilic and hydrophobic crosslinkers are obtained from the volume phase transition temperature behaviour, 1H high-resolution magic-angle sample spinning transverse magnetization relaxation NMR, and modified Flory-Rehner swelling theory. Firstly, considering a homogeneous morphology the number of subchains in the biohybrid microgel, the residual water in deswollen state as a function of crosslink density and the temperature dependence of the Flory biopolymer-water interaction parameters are reported for the biohybrid microgels prepared with hydrophilic (PEG-DGE) and hydrophobic (BS3) crosslinkers. The Flory-Rehner classical approach is subsequently modified taking into account the heterogeneities observed by NMR transverse relaxation measurements. Two differently mobile regions are determined, a hydrophobic domain and a crosslinking domain with relative reduced mobility. For the first time, the influence of chain mobility on the Flory interaction parameter is investigated through a modified Flory state equation. The contributions of amino-acids located in the hydrophobic and crosslinking domains in the polypeptide sequence are separated while analyzing the biopolymer-water interaction.

Metabolic Portraits of Breast Cancer by HR MAS MR Spectroscopy of Intact Tissue Samples.

PubMed

Haukaas, Tonje H; Euceda, Leslie R; Giskeødegård, Guro F; Bathen, Tone F

2017-05-16

Despite progress in early detection and therapeutic strategies, breast cancer remains the second leading cause of cancer-related death among women globally. Due to the heterogeneity and complexity of tumor biology, breast cancer patients with similar diagnosis might have different prognosis and response to treatment. Thus, deeper understanding of individual tumor properties is necessary. Cancer cells must be able to convert nutrients to biomass while maintaining energy production, which requires reprogramming of central metabolic processes in the cells. This phenomenon is increasingly recognized as a potential target for treatment, but also as a source for biomarkers that can be used for prognosis, risk stratification and therapy monitoring. Magnetic resonance (MR) metabolomics is a widely used approach in translational research, aiming to identify clinically relevant metabolic biomarkers or generate novel understanding of the molecular biology in tumors. Ex vivo proton high-resolution magic angle spinning (HR MAS) MR spectroscopy is widely used to study central metabolic processes in a non-destructive manner. Here we review the current status for HR MAS MR spectroscopy findings in breast cancer in relation to glucose, amino acid and choline metabolism.

Distinguishing polymorphs of the semiconducting pigment copper phthalocyanine by solid-state NMR and Raman spectroscopy.

PubMed

Shaibat, Medhat A; Casabianca, Leah B; Siberio-Pérez, Diana Y; Matzger, Adam J; Ishii, Yoshitaka

2010-04-08

Cu(II)(phthalocyanine) (CuPc) is broadly utilized as an archetypal molecular semiconductor and is the most widely used blue printing pigment. CuPc crystallizes in six different forms; the chemical and physical properties are substantially modulated by its molecular packing among these polymorphs. Despite the growing importance of this system, spectroscopic identification of different polymorphs for CuPc has posed difficulties. This study presents the first example of spectroscopic distinction of alpha- and beta-forms of CuPc, the most widely used polymorphs, by solid-state NMR (SSNMR) and Raman spectroscopy. (13)C high-resolution SSNMR spectra of alpha- and beta-CuPc using very-fast magic angle spinning (VFMAS) at 20 kHz show that hyperfine shifts sensitively reflect polymorphs of CuPc. The experimental results were confirmed by ab initio chemical shift calculations. (13)C and (1)H SSNMR relaxation times of alpha- and beta-CuPc under VFMAS also showed marked differences, presumably because of the difference in electronic spin correlation times in the two forms. Raman spectroscopy also provided another reliable method of differentiation between the two polymorphs.

Construction of a Quantum Matter Synthesizer

NASA Astrophysics Data System (ADS)

Trisnadi, Jonathan; McDonald, Mickey; Chin, Cheng

2017-04-01

We report progress on the construction of a new platform to manipulate ultracold atoms. The ``Quantum Matter Synthesizer (QMS)'' will have the capability of deterministically preparing large 2D arrays of atoms with single site addressability. Cesium atoms are first transferred into a science cell (specially textured to reduce reflectance to 0.1% across a wide range of wavelengths and incident angles) via a moving 1D lattice, where they are loaded into a magic-wavelength, far-detuned 2D optical lattice. Two NA=0.8 microscope objectives surround the science cell from above and below. The lower objective will be used to project an array of optical tweezers created via a digital micromirror device (DMD) onto the atom-trapping plane, which will be used to rearrange atoms into a desired configuration after first taking a site-resolved fluorescence image of the initial atomic distribution with the upper objective. We provide updates on our magnetic-optical trap and Raman-sideband cooling performance, characterization of the resolution of our microscope objectives, and stability tests for the objective mounting structure.

COLD MAGICS - Continuous Local Deformation Monitoring of an Arctic Geodetic Fundamental Station

NASA Technical Reports Server (NTRS)

Haas, Ruediger; Bergstrand, Sten

2010-01-01

We describe the experience gained in a project to continuously monitor the local tie at the Geodetic Observatory Ny-Alesund. A PC-controlled robotic total station was used to monitor survey prisms that were attached to survey pillars of the local network and the monuments used for geodetic VLBI and GNSS measurements. The monitoring lasted for seven days and had a temporal resolution of six minutes. The raw angle and distance measurements show clear sinusoidal signatures with a daily period, most strongly for a four-day period with 24 hours of sunshine. The derived topocentric coordinates of the survey prisms attached to the GNSS monument and the VLBI radio telescope act as approximation for the local tie. We detect clear signatures at the mm-level. With the current approach we cannot distinguish between real motion of the prisms and potential thermal influences on the instrument used for the observations. However, the project shows that continuous local tie monitoring is feasible today and in the future can and should be used for all geodetic co-location stations.

High-field 95 Mo and 183 W static and MAS NMR study of polyoxometalates.

PubMed

Haouas, Mohamed; Trébosc, Julien; Roch-Marchal, Catherine; Cadot, Emmanuel; Taulelle, Francis; Martineau-Corcos, Charlotte

2017-10-01

The potential of high-field NMR to measure solid-state 95 Mo and 183 W NMR in polyoxometalates (POMs) is explored using some archetypical structures like Lindqvist, Keggin and Dawson as model compounds that are well characterized in solution. NMR spectra in static and under magic angle spinning (MAS) were obtained, and their analysis allowed extraction of the NMR parameters, including chemical shift anisotropy and quadrupolar coupling parameters. Despite the inherent difficulties of measurement in solid state of these low-gamma NMR nuclei, due mainly to the low spectral resolution and poor signal-to-noise ratio, the observed global trends compare well with the solution-state NMR data. This would open an avenue for application of solid-state NMR to POMs, especially when liquid-state NMR is not possible, e.g., for poorly soluble or unstable compounds in solution, and for giant molecules with slow tumbling motion. This is the case of Keplerate where we provide here the first NMR characterization of this class of POMs in the solid state. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Solvent signal suppression for high-resolution MAS-DNP

NASA Astrophysics Data System (ADS)

Lee, Daniel; Chaudhari, Sachin R.; De Paëpe, Gaël

2017-05-01

Dynamic nuclear polarization (DNP) has become a powerful tool to substantially increase the sensitivity of high-field magic angle spinning (MAS) solid-state NMR experiments. The addition of dissolved hyperpolarizing agents usually results in the presence of solvent signals that can overlap and obscure those of interest from the analyte. Here, two methods are proposed to suppress DNP solvent signals: a Forced Echo Dephasing experiment (FEDex) and TRAnsfer of Populations in DOuble Resonance Echo Dephasing (TRAPDORED) NMR. These methods reintroduce a heteronuclear dipolar interaction that is specific to the solvent, thereby forcing a dephasing of recoupled solvent spins and leaving acquired NMR spectra free of associated resonance overlap with the analyte. The potency of these methods is demonstrated on sample types common to MAS-DNP experiments, namely a frozen solution (of L-proline) and a powdered solid (progesterone), both containing deuterated glycerol as a DNP solvent. The proposed methods are efficient, simple to implement, compatible with other NMR experiments, and extendable past spectral editing for just DNP solvents. The sensitivity gains from MAS-DNP in conjunction with FEDex or TRAPDORED then permits rapid and uninterrupted sample analysis.

Studies of minute quantities of natural abundance molecules using 2D heteronuclear correlation spectroscopy under 100kHz MAS

DOE PAGES

Nishiyama, Y.; Kobayashi, T.; Malon, M.; ...

2015-02-16

Two-dimensional 1H{ 13C} heteronuclear correlation solid-state NMR spectra of naturally abundant solid materials are presented, acquired using the 0.75-mm magic angle spinning (MAS) probe at spinning rates up to 100 kHz. In spite of the miniscule sample volume (290 nL), high-quality HSQC-type spectra of bulk samples as well as surface-bound molecules can be obtained within hours of experimental time. The experiments are compared with those carried out at 40 kHz MAS using a 1.6-mm probe, which offered higher overall sensitivity due to a larger rotor volume. The benefits of ultrafast MAS in such experiments include superior resolution in 1H dimensionmore » without resorting to 1H– 1H homonuclear RF decoupling, easy optimization, and applicability to mass-limited samples. As a result, the HMQC spectra of surface-bound species can be also acquired under 100 kHz MAS, although the dephasing of transverse magnetization has significant effect on the efficiency transfer under MAS alone.« less

Complete (1)H resonance assignment of beta-maltose from (1)H-(1)H DQ-SQ CRAMPS and (1)H (DQ-DUMBO)-(13)C SQ refocused INEPT 2D solid-state NMR spectra and first principles GIPAW calculations.

PubMed

Webber, Amy L; Elena, Bénédicte; Griffin, John M; Yates, Jonathan R; Pham, Tran N; Mauri, Francesco; Pickard, Chris J; Gil, Ana M; Stein, Robin; Lesage, Anne; Emsley, Lyndon; Brown, Steven P

2010-07-14

A disaccharide is a challenging case for high-resolution (1)H solid-state NMR because of the 24 distinct protons (14 aliphatic and 10 OH) having (1)H chemical shifts that all fall within a narrow range of approximately 3 to 7 ppm. High-resolution (1)H (500 MHz) double-quantum (DQ) combined rotation and multiple pulse sequence (CRAMPS) solid-state NMR spectra of beta-maltose monohydrate are presented. (1)H-(1)H DQ-SQ CRAMPS spectra are presented together with (1)H (DQ)-(13)C correlation spectra obtained with a new pulse sequence that correlates a high-resolution (1)H DQ dimension with a (13)C single quantum (SQ) dimension using the refocused INEPT pulse-sequence element to transfer magnetization via one-bond (13)C-(1)H J couplings. Compared to the observation of only a single broad peak in a (1)H DQ spectrum recorded at 30 kHz magic-angle spinning (MAS), the use of DUMBO (1)H homonuclear decoupling in the (1)H DQ CRAMPS experiment allows the resolution of distinct DQ correlation peaks which, in combination with first-principles chemical shift calculations based on the GIPAW (Gauge Including Projector Augmented Waves) plane-wave pseudopotential approach, enables the assignment of the (1)H resonances to the 24 distinct protons. We believe this to be the first experimental solid-state NMR determination of the hydroxyl OH (1)H chemical shifts for a simple sugar. Variable-temperature (1)H-(1)H DQ CRAMPS spectra reveal small increases in the (1)H chemical shifts of the OH resonances upon decreasing the temperature from 348 K to 248 K.

Study of the ferroelastic phase transition in the tetraethylammonium compound [N(C{sub 2}H{sub 5}){sub 4}]{sub 2}ZnBr{sub 4} by magic-angle spinning and static NMR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, Ae Ran, E-mail: aeranlim@hanmail.net, E-mail: arlim@jj.ac.kr

The ferroelastic phase transition of tetraethylammonium compound [N(C{sub 2}H{sub 5}){sub 4}]{sub 2}ZnBr{sub 4} at the phase transition temperature (T{sub C}) = 283 K was characterized by magic-angle spinning (MAS) and static nuclear magnetic resonance (NMR), and confirmed by optical polarizing spectroscopy. The structural geometry near T{sub C} was studied in terms of the chemical shifts and the spin-lattice relaxation times T{sub 1ρ} in the rotating frame for {sup 1}H MAS NMR and {sup 13}C cross-polarization (CP)/MAS NMR. The two inequivalent ethyl groups were distinguishable in the {sup 13}C NMR spectrum, and the T{sub 1ρ} results indicate that they undergo tumblingmore » motion above T{sub C} in a coupled manner. From the {sup 14}N NMR results, the two nitrogen nuclei in the N(C{sub 2}H{sub 5}){sub 4}{sup +} ions were distinguishable above T{sub C}, and the splitting in the spectra below T{sub C} was related to the ferroelastic domains with different orientations.« less

A LOW-E MAGIC ANGLE SPINNING PROBE FOR BIOLOGICAL SOLID STATE NMR AT 750 MHz

PubMed Central

McNeill, Seth A.; Gor’kov, Peter L.; Shetty, Kiran; Brey, William W.; Long, Joanna R.

2009-01-01

Crossed-coil NMR probes are a useful tool for reducing sample heating for biological solid state NMR. In a crossed-coil probe, the higher frequency 1H field, which is the primary source of sample heating in conventional probes, is produced by a separate low-inductance resonator. Because a smaller driving voltage is required, the electric field across the sample and the resultant heating is reduced. In this work we describe the development of a magic angle spinning (MAS) solid state NMR probe utilizing a dual resonator. This dual resonator approach, referred to as “Low-E,” was originally developed to reduce heating in samples of mechanically aligned membranes. The study of inherently dilute systems, such as proteins in lipid bilayers, via MAS techniques requires large sample volumes at high field to obtain spectra with adequate signal-to-noise ratio under physiologically relevant conditions. With the Low-E approach, we are able to obtain homogeneous and sufficiently strong radiofrequency fields for both 1H and 13C frequencies in a 4 mm probe with a 1H frequency of 750 MHz. The performance of the probe using windowless dipolar recoupling sequences is demonstrated on model compounds as well as membrane embedded peptides. PMID:19138870

Chemical and carbon-13 cross-polarization magic-angle spinning nuclear magnetic resonance characterization of logyard fines from British Columbia.

PubMed

Preston, C M; Forrester, P D

2004-01-01

Phasing out beehive burners and rising costs for landfilling have increased the need to widen options for utilization of the smaller size fractions of woody wastes generated during log handling and sawmilling in British Columbia. We characterized several size classes of logyard fines up to 16 mm sampled from coastal and interior operations. Total C, total N, ash, and condensed tannin concentrations were consistent with properties derived largely from wood, with varying proportions of bark and mixing with mineral soil. Especially for < 3-mm fractions, the latter resulted in high ash contents that would make them unsuitable for fuel. Solid-state 13C cross-polarization magic-angle spinning (CPMAS) nuclear magnetic resonance (NMR) spectra were consistent with the chemical data, with high O-alkyl intensity and similarity to naturally occurring woody forest floor; no samples were high in aromatic or phenolic C. Aqueous extracts of two < 16-mm fines, which accounted for only a small proportion of the total C, were enriched in alkyl C and had low or undetectable tannins. Application to forest sites might cause short-term immobilization of N, but also might include possible longer-term benefits from reduction of N loss after harvesting and restoration of soil organic matter in degraded sites.

Perturbation of nuclear spin polarizations in solid state NMR of nitroxide-doped samples by magic-angle spinning without microwaves.

PubMed

Thurber, Kent R; Tycko, Robert

2014-05-14

We report solid state (13)C and (1)H nuclear magnetic resonance (NMR) experiments with magic-angle spinning (MAS) on frozen solutions containing nitroxide-based paramagnetic dopants that indicate significant perturbations of nuclear spin polarizations without microwave irradiation. At temperatures near 25 K, (1)H and cross-polarized (13)C NMR signals from (15)N,(13)C-labeled L-alanine in trinitroxide-doped glycerol/water are reduced by factors as large as six compared to signals from samples without nitroxide doping. Without MAS or at temperatures near 100 K, differences between signals with and without nitroxide doping are much smaller. We attribute most of the reduction of NMR signals under MAS near 25 K to nuclear spin depolarization through the cross-effect dynamic nuclear polarization mechanism, in which three-spin flips drive nuclear polarizations toward equilibrium with spin polarization differences between electron pairs. When T1e is sufficiently long relative to the MAS rotation period, the distribution of electron spin polarization across the nitroxide electron paramagnetic resonance lineshape can be very different from the corresponding distribution in a static sample at thermal equilibrium, leading to the observed effects. We describe three-spin and 3000-spin calculations that qualitatively reproduce the experimental observations.

NMR longitudinal relaxation enhancement in metal halides by heteronuclear polarization exchange during magic-angle spinning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shmyreva, Anna A.; Safdari, Majid; Furó, István

2016-06-14

Orders of magnitude decrease of {sup 207}Pb and {sup 199}Hg NMR longitudinal relaxation times T{sub 1} upon magic-angle-spinning (MAS) are observed and systematically investigated in solid lead and mercury halides MeX{sub 2} (Me = Pb, Hg and X = Cl, Br, I). In lead(II) halides, the most dramatic decrease of T{sub 1} relative to that in a static sample is in PbI{sub 2}, while it is smaller but still significant in PbBr{sub 2}, and not detectable in PbCl{sub 2}. The effect is magnetic-field dependent but independent of the spinning speed in the range 200–15 000 Hz. The observed relaxation enhancementmore » is explained by laboratory-frame heteronuclear polarization exchange due to crossing between energy levels of spin-1/2 metal nuclei and adjacent quadrupolar-spin halogen nuclei. The enhancement effect is also present in lead-containing organometal halide perovskites. Our results demonstrate that in affected samples, it is the relaxation data recorded under non-spinning conditions that characterize the local properties at the metal sites. A practical advantage of fast relaxation at slow MAS is that spectral shapes with orientational chemical shift anisotropy information well retained can be acquired within a shorter experimental time.« less

Double cross polarization for the indirect detection of nitrogen-14 nuclei in magic angle spinning NMR spectroscopy

NASA Astrophysics Data System (ADS)

Carnevale, Diego; Ji, Xiao; Bodenhausen, Geoffrey

2017-11-01

Nitrogen-14 NMR spectra at fast magic-angle spinning rates can be acquired indirectly by means of two-dimensional techniques based on double cross polarization transfer 1H → 14N →1H. Experimental evidence is given for polycrystalline samples of glycine, l-histidine, and the dipeptide Ala-Gly. Either one-bond or long-range correlations can be favored by choosing the length of the cross polarization contact pulses. Longer contact pulses allow the detection of unprotonated nitrogen sites. In contrast to earlier methods that exploited second-order quadrupolar/dipolar cross-terms, cross polarization operates in the manner of the method of Hartmann and Hahn, even for 14N quadrupolar couplings up to 4 MHz. Simulations explain why amorphous samples tend to give rise to featureless spectra because the 14N quadrupolar interactions may vary dramatically with the lattice environment. The experiments are straightforward to set up and are shown to be effective for different nitrogen environments and robust with respect to the rf-field strengths and to the 14N carrier frequency during cross polarization. The efficiency of indirect detection of 14N nuclei by double cross polarization is shown to be similar to that of isotopically enriched 13C nuclei.

In vivo and ex vivo magnetic resonance spectroscopy of the infarct and the subventricular zone in experimental stroke

PubMed Central

Jiménez-Xarrié, Elena; Davila, Myriam; Gil-Perotín, Sara; Jurado-Rodríguez, Andrés; Candiota, Ana Paula; Delgado-Mederos, Raquel; Lope-Piedrafita, Silvia; García-Verdugo, José Manuel; Arús, Carles; Martí-Fàbregas, Joan

2015-01-01

Ex vivo high-resolution magic-angle spinning (HRMAS) provides metabolic information with higher sensitivity and spectral resolution than in vivo magnetic resonance spectroscopy (MRS). Therefore, we used both techniques to better characterize the metabolic pattern of the infarct and the neural progenitor cells (NPCs) in the ipsilateral subventricular zone (SVZi). Ischemic stroke rats were divided into three groups: G0 (non-stroke controls, n=6), G1 (day 1 after stroke, n=6), and G7 (days 6 to 8 after stroke, n=12). All the rats underwent MRS. Three rats per group were analyzed by HRMAS. The remaining rats were used for immunohistochemical studies. In the infarct, both techniques detected significant metabolic changes. The most relevant change was in mobile lipids (2.80 ppm) in the G7 group (a 5.53- and a 3.95-fold increase by MRS and HRMAS, respectively). In the SVZi, MRS did not detect any significant metabolic change. However, HRMAS detected a 2.70-fold increase in lactate and a 0.68-fold decrease in N-acetylaspartate in the G1 group. None of the metabolites correlated with the 1.37-fold increase in NPCs detected by immunohistochemistry in the G7 group. In conclusion, HRMAS improves the metabolic characterization of the brain in experimental ischemic stroke. However, none of the metabolites qualifies as a surrogate biomarker of NPCs. PMID:25605287

Imaging secondary structure of individual amyloid fibrils of a β2-microglobulin fragment using near-field infrared spectroscopy.

PubMed

Paulite, Melissa; Fakhraai, Zahra; Li, Isaac T S; Gunari, Nikhil; Tanur, Adrienne E; Walker, Gilbert C

2011-05-18

Amyloid fibril diseases are characterized by the abnormal production of aggregated proteins and are associated with many types of neuro- and physically degenerative diseases. X-ray diffraction techniques, solid-state magic-angle spinning NMR spectroscopy, circular dichroism (CD) spectroscopy, and transmission electron microscopy studies have been utilized to detect and examine the chemical, electronic, material, and structural properties of amyloid fibrils at up to angstrom spatial resolution. However, X-ray diffraction studies require crystals of the fibril to be analyzed, while other techniques can only probe the bulk solution or solid samples. In the work reported here, apertureless near-field scanning infrared microscopy (ANSIM) was used to probe the secondary structure of individual amyloid fibrils made from an in vitro solution. Simultaneous topographic and infrared images of individual amyloid fibrils synthesized from the #21-31 peptide fragment of β(2)-microglobulin were acquired. Using this technique, IR spectra of the amyloid fibrils were obtained with a spatial resolution of less than 30 nm. It is observed that the experimental scattered field spectrum correlates strongly with that calculated using the far-field absorption spectrum. The near-field images of the amyloid fibrils exhibit much lower scattering of the IR radiation at approximately 1630 cm(-1). In addition, the near-field images also indicate that composition and/or structural variations among individual amyloid fibrils were present. © 2011 American Chemical Society

[Polyhedron of Dürer's engraving Melancholia. I--a Nürnberg sketch representing the Archimedean body].

PubMed

Weitzel, Hans

2007-01-01

New mathematical hypotheses are postulated concerning the truncated rhombohedron in Dürer's engraving Melencolia.I as well as the relation of the rhombohedron to the magic square. The two free parameters of a truncated rhombohedron have to be chosen in a way that (i) its front orthogonal elevation is nearly quadratical and with the form of the magic square, and that (ii) it possesses approximately a circumscribed sphere. Both conditions result in a value of 79.2 degrees for the angle of the rhombohedron. Measuring two lengths of the rhombohedron of the engraving yields the same value. In the magic square, the numbers are positioned in a way that the connection lines between four numbers give the sum 34 for lines which are the projection lines of the edges of the rhombohedron. In the Nürnberg-Codex of Dürer's manuscripts, exists a page with some sketches of mostly archimedean solids. One sketch represents a pentagon with approximately the measures of the six lateral faces of the truncated rhombohedron. It has to be looked upon as a preliminary sketch for the solid of the engraving. In 1543 Augustin Hirschvogel from Nürnberg, as the next after Dürer, rediscovered a further archimedean solid; this rediscovering has been attributed to D. Barbaro until now.

Theoretical description of RESPIRATION-CP

NASA Astrophysics Data System (ADS)

Nielsen, Anders B.; Tan, Kong Ooi; Shankar, Ravi; Penzel, Susanne; Cadalbert, Riccardo; Samoson, Ago; Meier, Beat H.; Ernst, Matthias

2016-02-01

We present a quintuple-mode operator-based Floquet approach to describe arbitrary amplitude modulated cross polarization experiments under magic-angle spinning (MAS). The description is used to analyze variants of the RESPIRATION approach (RESPIRATIONCP) where recoupling conditions and the corresponding first-order effective Hamiltonians are calculated, validated numerically and compared to experimental results for 15N-13C coherence transfer in uniformly 13C,15N-labeled alanine and in uniformly 2H,13C,15N-labeled (deuterated and 100% back-exchanged) ubiquitin at spinning frequencies of 16.7 and 90.9 kHz. Similarities and differences between different implementations of the RESPIRATIONCP sequence using either CW irradiation or small flip-angle pulses are discussed.

CP/MAS /sup 13/C NMR spectroscopic study of chlorophyll a in the solid state

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, C.E.; Spencer, R.B.; Burger, V.T.

1983-09-01

Solid-state cross-polarization, magic-angle sample spinning carbon-13 nuclear magnetic resonance spectra have been recorded on chlorophyll a- water aggregates, methyl pyrochlorophyllide a and methyl pyropheophorbide a (derivatives that lack a phytyl chain). Spectra have also been collected under a decoupling regime in which resonances of certain hydrogen-bearing carbon atoms are suppressed. These observations are used to assign the solid state spectra.

RF waveguide phase-directed power combiners

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nantista, Christopher D.; Dolgashev, Valery A.; Tantawi, Sami G.

2017-05-02

High power RF phase-directed power combiners include magic H hybrid and/or superhybrid circuits oriented in orthogonal H-planes and connected using E-plane bends and/or twists to produce compact 3D waveguide circuits, including 8.times.8 and 16.times.16 combiners. Using phase control at the input ports, RF power can be directed to a single output port, enabling fast switching between output ports for applications such as multi-angle radiation therapy.

Angle-dependent quantum Otto heat engine based on coherent dipole-dipole coupling

NASA Astrophysics Data System (ADS)

Su, Shan-He; Luo, Xiao-Qing; Chen, Jin-Can; Sun, Chang-Pu

2016-08-01

Electromagnetic interactions between molecules or within a molecule have been widely observed in biological systems and exhibit broad application for molecular structural studies. Quantum delocalization of molecular dipole moments has inspired researchers to explore new avenues to utilize this physical effect for energy harvesting devices. Herein, we propose a simple model of the angle-dependent quantum Otto heat engine which seeks to facilitate the conversion of heat to work. Unlike previous studies, the adiabatic processes are accomplished by varying only the directions of the magnetic field. We show that the heat engine continues to generate power when the angle relative to the vector r joining the centres of coupled dipoles departs from the magic angle θm where the static coupling vanishes. A significant improvement in the device performance has to be attributed to the presence of the quantum delocalized levels associated with the coherent dipole-dipole coupling. These results obtained may provide a promising model for the biomimetic design and fabrication of quantum energy generators.

CAIPIRINHA accelerated SPACE enables 10-min isotropic 3D TSE MRI of the ankle for optimized visualization of curved and oblique ligaments and tendons.

PubMed

Kalia, Vivek; Fritz, Benjamin; Johnson, Rory; Gilson, Wesley D; Raithel, Esther; Fritz, Jan

2017-09-01

To test the hypothesis that a fourfold CAIPIRINHA accelerated, 10-min, high-resolution, isotropic 3D TSE MRI prototype protocol of the ankle derives equal or better quality than a 20-min 2D TSE standard protocol. Following internal review board approval and informed consent, 3-Tesla MRI of the ankle was obtained in 24 asymptomatic subjects including 10-min 3D CAIPIRINHA SPACE TSE prototype and 20-min 2D TSE standard protocols. Outcome variables included image quality and visibility of anatomical structures using 5-point Likert scales. Non-parametric statistical testing was used. P values ≤0.001 were considered significant. Edge sharpness, contrast resolution, uniformity, noise, fat suppression and magic angle effects were without statistical difference on 2D and 3D TSE images (p > 0.035). Fluid was mildly brighter on intermediate-weighted 2D images (p < 0.001), whereas 3D images had substantially less partial volume, chemical shift and no pulsatile-flow artifacts (p < 0.001). Oblique and curved planar 3D images resulted in mildly-to-substantially improved visualization of joints, spring, bifurcate, syndesmotic, collateral and sinus tarsi ligaments, and tendons (p < 0.001, respectively). 3D TSE MRI with CAIPIRINHA acceleration enables high-spatial resolution oblique and curved planar MRI of the ankle and visualization of ligaments, tendons and joints equally well or better than a more time-consuming anisotropic 2D TSE MRI. • High-resolution 3D TSE MRI improves visualization of ankle structures. • Limitations of current 3D TSE MRI include long scan times. • 3D CAIPIRINHA SPACE allows now a fourfold-accelerated data acquisition. • 3D CAIPIRINHA SPACE enables high-spatial-resolution ankle MRI within 10 min. • 10-min 3D CAIPIRINHA SPACE produces equal-or-better quality than 20-min 2D TSE.

The Magnetics Information Consortium (MagIC) Online Database: Uploading, Searching and Visualizing Paleomagnetic and Rock Magnetic Data

NASA Astrophysics Data System (ADS)

Koppers, A.; Tauxe, L.; Constable, C.; Pisarevsky, S.; Jackson, M.; Solheid, P.; Banerjee, S.; Johnson, C.; Genevey, A.; Delaney, R.; Baker, P.; Sbarbori, E.

2005-12-01

The Magnetics Information Consortium (MagIC) operates an online relational database including both rock and paleomagnetic data. The goal of MagIC is to store all measurements and their derived properties for studies of paleomagnetic directions (inclination, declination) and their intensities, and for rock magnetic experiments (hysteresis, remanence, susceptibility, anisotropy). MagIC is hosted under EarthRef.org at http://earthref.org/MAGIC/ and has two search nodes, one for paleomagnetism and one for rock magnetism. These nodes provide basic search capabilities based on location, reference, methods applied, material type and geological age, while allowing the user to drill down from sites all the way to the measurements. At each stage, the data can be saved and, if the available data supports it, the data can be visualized by plotting equal area plots, VGP location maps or typical Zijderveld, hysteresis, FORC, and various magnetization and remanence diagrams. All plots are made in SVG (scalable vector graphics) and thus can be saved and easily read into the user's favorite graphics programs without loss of resolution. User contributions to the MagIC database are critical to achieve a useful research tool. We have developed a standard data and metadata template (version 1.6) that can be used to format and upload all data at the time of publication in Earth Science journals. Software tools are provided to facilitate easy population of these templates within Microsoft Excel. These tools allow for the import/export of text files and they provide advanced functionality to manage/edit the data, and to perform various internal checks to high grade the data and to make them ready for uploading. The uploading is all done online by using the MagIC Contribution Wizard at http://earthref.org/MAGIC/upload.htm that takes only a few minutes to process a contribution of approximately 5,000 data records. After uploading these standardized MagIC template files will be stored in the digital archives of EarthRef.org from where they can be downloaded at all times. Finally, the contents of these template files will be automatically parsed into the online relational database, making the data available for online searches in the paleomagnetic and rock magnetic search nodes. The MagIC database contains all data transferred from the IAGA paleomagnetic poles database (GPMDB), the lava flow paleosecular variation database (PSVRL), lake sediment database (SECVR) and the PINT database. In addition to that a substantial number of data compiled under the Time Averaged Field Investigations project is now included plus a significant fraction of the data collected at SIO and the IRM. Ongoing additions of legacy data include ~40 papers from studies on the Hawaiian Islands, data compilations from archeomagnetic studies and updates to the lake sediment dataset.

Corrigendum to "Multiple-quantum spin counting in magic-angle-spinning NMR via low-power symmetry-based dipolar recoupling" [J. Magn. Reson. 236 (2013) 31-40

NASA Astrophysics Data System (ADS)

Teymoori, Gholamhasan; Pahari, Bholanath; Viswanathan, Elumalai; Edén, Mattias

2017-03-01

The authors regret that an inappropriate NMR data processing, not known to all authors at the time of publication, was used to produce the multiple-quantum coherence (MQC) spin counting data presented in our article: this lead to artificially enhanced results, particularly concerning those obtained at long MQC excitation intervals (τexc). Here we reproduce Figs. 4-7 with correctly processed data.

Hexagonal ice in pure water and biological NMR samples.

PubMed

Bauer, Thomas; Gath, Julia; Hunkeler, Andreas; Ernst, Matthias; Böckmann, Anja; Meier, Beat H

2017-01-01

Ice, in addition to "liquid" water and protein, is an important component of protein samples for NMR spectroscopy at subfreezing temperatures but it has rarely been observed spectroscopically in this context. We characterize its spectroscopic behavior in the temperature range from 100 to 273 K, and find that it behaves like pure water ice. The interference of magic-angle spinning (MAS) as well as rf multiple-pulse sequences with Bjerrum-defect motion greatly influences the ice spectra.

Observation of NMR noise from solid samples.

PubMed

Schlagnitweit, Judith; Dumez, Jean-Nicolas; Nausner, Martin; Jerschow, Alexej; Elena-Herrmann, Bénédicte; Müller, Norbert

2010-11-01

We demonstrate that proton NMR noise signals, i.e. NMR spectra without excitation by radio frequency, can be obtained from solid samples. Experimental results are shown for static and magic-angle spinning conditions. In addition, a tuning procedure based on the probes' NMR noise characteristics and similar to the one described previously for liquids probes can also be used to optimize signal-to-noise ratios in ¹H-MAS experiments. Copyright © 2010 Elsevier Inc. All rights reserved.

Quantification In Situ of Crystalline Cholesterol and Calcium Phosphate Hydroxyapatite in Human Atherosclerotic Plaques by Solid-State Magic Angle Spinning NMR

PubMed Central

Guo, Wen; Morrisett, Joel D.; DeBakey, Michael E.; Lawrie, Gerald M.; Hamilton, James A.

2010-01-01

Because of renewed interest in the progression, stabilization, and regression of atherosclerotic plaques, it has become important to develop methods for characterizing structural features of plaques in situ and noninvasively. We present a nondestructive method for ex vivo quantification of 2 solid-phase components of plaques: crystalline cholesterol and calcium phosphate salts. Magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectra of human carotid endarterectomy plaques revealed 13C resonances of crystalline cholesterol monohydrate and a 31P resonance of calcium phosphate hydroxyapatite (CPH). The spectra were obtained under conditions in which there was little or no interference from other chemical components and were suitable for quantification in situ of the crystalline cholesterol and CPH. Carotid atherosclerotic plaques showed a wide variation in their crystalline cholesterol content. The calculated molar ratio of liquid-crystalline cholesterol to phospholipid ranged from 1.1 to 1.7, demonstrating different capabilities of the phospholipids to reduce crystallization of cholesterol. The spectral properties of the phosphate groups in CPH in carotid plaques were identical to those of CPH in bone. 31P MAS NMR is a simple, rapid method for quantification of calcium phosphate salts in tissue without extraction and time-consuming chemical analysis. Crystalline phases in intact atherosclerotic plaques (ex vivo) can be quantified accurately by solid-state 13C and 31PMAS NMR spectroscopy. PMID:10845882

Multiple acquisitions via sequential transfer of orphan spin polarization (MAeSTOSO): How far can we push residual spin polarization in solid-state NMR?

NASA Astrophysics Data System (ADS)

Gopinath, T.; Veglia, Gianluigi

2016-06-01

Conventional multidimensional magic angle spinning (MAS) solid-state NMR (ssNMR) experiments detect the signal arising from the decay of a single coherence transfer pathway (FID), resulting in one spectrum per acquisition time. Recently, we introduced two new strategies, namely DUMAS (DUal acquisition Magic Angle Spinning) and MEIOSIS (Multiple ExperIments via Orphan SpIn operatorS), that enable the simultaneous acquisitions of multidimensional ssNMR experiments using multiple coherence transfer pathways. Here, we combined the main elements of DUMAS and MEIOSIS to harness both orphan spin operators and residual polarization and increase the number of simultaneous acquisitions. We show that it is possible to acquire up to eight two-dimensional experiments using four acquisition periods per each scan. This new suite of pulse sequences, called MAeSTOSO for Multiple Acquisitions via Sequential Transfer of Orphan Spin pOlarization, relies on residual polarization of both 13C and 15N pathways and combines low- and high-sensitivity experiments into a single pulse sequence using one receiver and commercial ssNMR probes. The acquisition of multiple experiments does not affect the sensitivity of the main experiment; rather it recovers the lost coherences that are discarded, resulting in a significant gain in experimental time. Both merits and limitations of this approach are discussed.

The use of a selective saturation pulse to suppress t1 noise in two-dimensional 1H fast magic angle spinning solid-state NMR spectroscopy

NASA Astrophysics Data System (ADS)

Robertson, Aiden J.; Pandey, Manoj Kumar; Marsh, Andrew; Nishiyama, Yusuke; Brown, Steven P.

2015-11-01

A selective saturation pulse at fast magic angle spinning (MAS) frequencies (60+ kHz) suppresses t1 noise in the indirect dimension of two-dimensional 1H MAS NMR spectra. The method is applied to a synthetic nucleoside with an intense methyl 1H signal due to triisopropylsilyl (TIPS) protecting groups. Enhanced performance in terms of suppressing the methyl signal while minimising the loss of signal intensity of nearby resonances of interest relies on reducing spin diffusion - this is quantified by comparing two-dimensional 1H NOESY-like spin diffusion spectra recorded at 30-70 kHz MAS. For a saturation pulse centred at the methyl resonance, the effect of changing the nutation frequency at different MAS frequencies as well as the effect of changing the pulse duration is investigated. By applying a pulse of duration 30 ms and nutation frequency 725 Hz at 70 kHz MAS, a good compromise of significant suppression of the methyl resonance combined with the signal intensity of resonances greater than 5 ppm away from the methyl resonance being largely unaffected is achieved. The effectiveness of using a selective saturation pulse is demonstrated for both homonuclear 1H-1H double quantum (DQ)/single quantum (SQ) MAS and 14N-1H heteronuclear multiple quantum coherence (HMQC) two-dimensional solid-state NMR experiments.

Self-diffusion of electrolyte species in model battery electrodes using Magic Angle Spinning and Pulsed Field Gradient Nuclear Magnetic Resonance

NASA Astrophysics Data System (ADS)

Tambio, Sacris Jeru; Deschamps, Michaël; Sarou-Kanian, Vincent; Etiemble, Aurélien; Douillard, Thierry; Maire, Eric; Lestriez, Bernard

2017-09-01

Lithium-ion batteries are electrochemical storage devices using the electrochemical activity of the lithium ion in relation to intercalation compounds owing to mass transport phenomena through diffusion. Diffusion of the lithium ion in the electrode pores has been poorly understood due to the lack of experimental techniques for measuring its self-diffusion coefficient in porous media. Magic-Angle Spinning, Pulsed Field Gradient, Stimulated-Echo Nuclear Magnetic Resonance (MAS-PFG-STE NMR) was used here for the first time to measure the self-diffusion coefficients of the electrolyte species in the LP30 battery electrolyte (i.e. a 1 M solution of LiPF6 dissolved in 1:1 Ethylene Carbonate - Dimethyl Carbonate) in model composites. These composite electrodes were made of alumina, carbon black and PVdF-HFP. Alumina's magnetic susceptibility is close to the measured magnetic susceptibility of the LP30 electrolyte thereby limiting undesirable internal field gradients. Interestingly, the self-diffusion coefficient of lithium ions decreases with increasing carbon content. FIB-SEM was used to describe the 3D geometry of the samples. The comparison between the reduction of self-diffusion coefficients as measured by PFG-NMR and as geometrically derived from FIB/SEM tortuosity values highlights the contribution of specific interactions at the material/electrolyte interface on the lithium transport properties.

Magic angle spinning NMR below 6 K with a computational fluid dynamics analysis of fluid flow and temperature gradients

NASA Astrophysics Data System (ADS)

Sesti, Erika L.; Alaniva, Nicholas; Rand, Peter W.; Choi, Eric J.; Albert, Brice J.; Saliba, Edward P.; Scott, Faith J.; Barnes, Alexander B.

2018-01-01

We report magic angle spinning (MAS) up to 8.5 kHz with a sample temperature below 6 K using liquid helium as a variable temperature fluid. Cross polarization 13C NMR spectra exhibit exquisite sensitivity with a single transient. Remarkably, 1H saturation recovery experiments show a 1H T1 of 21 s with MAS below 6 K in the presence of trityl radicals in a glassy matrix. Leveraging the thermal spin polarization available at 4.2 K versus 298 K should result in 71 times higher signal intensity. Taking the 1H longitudinal relaxation into account, signal averaging times are therefore predicted to be expedited by a factor of >500. Computer assisted design (CAD) and finite element analysis were employed in both the design and diagnostic stages of this cryogenic MAS technology development. Computational fluid dynamics (CFD) models describing temperature gradients and fluid flow are presented. The CFD models bearing and drive gas maintained at 100 K, while a colder helium variable temperature fluid stream cools the center of a zirconia rotor. Results from the CFD were used to optimize the helium exhaust path and determine the sample temperature. This novel cryogenic experimental platform will be integrated with pulsed dynamic nuclear polarization and electron decoupling to interrogate biomolecular structure within intact human cells.

Analysis of the Electronic Structure of the Special Pair of a Bacterial Photosynthetic Reaction Center by 13 C Photochemically Induced Dynamic Nuclear Polarization Magic-Angle Spinning NMR Using a Double-Quantum Axis.

PubMed

Najdanova, Marija; Gräsing, Daniel; Alia, A; Matysik, Jörg

2018-01-01

The origin of the functional symmetry break in bacterial photosynthesis challenges since several decades. Although structurally very similar, the two branches of cofactors in the reaction center (RC) protein complex act very differently. Upon photochemical excitation, an electron is transported along one branch, while the other remains inactive. Photochemically induced dynamic nuclear polarization (photo-CIDNP) magic-angle spinning (MAS) 13 C NMR revealed that the two bacteriochlorophyll cofactors forming the "Special Pair" donor dimer are already well distinguished in the electronic ground state. These previous studies are relying solely on 13 C- 13 C correlation experiments as radio-frequency-driven recoupling (RFDR) and dipolar-assisted rotational resonance (DARR). Obviously, the chemical-shift assignment is difficult in a dimer of tetrapyrrole macrocycles, having eight pyrrole rings of similar chemical shifts. To overcome this problem, an INADEQUATE type of experiment using a POST C7 symmetry-based approach is applied to selectively isotope-labeled bacterial RC of Rhodobacter (R.) sphaeroides wild type (WT). We, therefore, were able to distinguish unresolved sites of the macromolecular dimer. The obtained chemical-shift pattern is in-line with a concentric assembly of negative charge within the common center of the Special Pair supermolecule in the electronic ground state. © 2017 The American Society of Photobiology.

Interplay of spherical closed shells and N /Z asymmetry in quasifission dynamics

NASA Astrophysics Data System (ADS)

Mohanto, G.; Hinde, D. J.; Banerjee, K.; Dasgupta, M.; Jeung, D. Y.; Simenel, C.; Simpson, E. C.; Wakhle, A.; Williams, E.; Carter, I. P.; Cook, K. J.; Luong, D. H.; Palshetkar, C. S.; Rafferty, D. C.

2018-05-01

Background: Quasifission (QF) has gained tremendous importance in heavy-ion nuclear physics research because of its strong influence on superheavy-element synthesis. Collisions involving closed-shell nuclei in the entrance channel are found to affect the QF reaction mechanism. Hence, it is important to improve the understanding of their effect on QF. Apart from that, some recent studies show that the difference in N /Z of reaction partners influences the reaction dynamics. Since heavier doubly magic nuclei have different N /Z than lighter doubly magic nuclei, it is important to understand the effect of N /Z mismatch as well as the effect of shell closures. Purpose: To investigate the effect of entrance-channel shell closures and N /Z asymmetry on QF. The reactions were chosen to decouple these effects from the contributions of other entrance-channel parameters. Method: Fission fragment mass-angle distributions were measured using the CUBE fission spectrometer, consisting of two large area position-sensitive multi-wire proportional counters (MWPCs), for five reactions, namely, 50Cr+208Pb , 52Cr+Pb,208206 , 54Cr+Pb,208204 . Result: Two components were observed in the measured fragment mass angle distribution, a fast mass-asymmetric quasifission and a slow mass-symmetric component having a less significant mass-angle correlation. The ratio of these components was found to depend on spherical closed shells in the entrance channel nuclei and the magnitude of the N /Z mismatch between the two reaction partners, as well as the beam energy. Conclusions: Entrance-channel spherical closed shells can enhance compound nucleus formation provided the N /Z asymmetry is small. Increase in the N /Z asymmetry is expected to destroy the effect of entrance-channel spherical closed shells, through nucleon transfer reactions.

Creating Magic Squares.

ERIC Educational Resources Information Center

Lyon, Betty Clayton

1990-01-01

One method of making magic squares using a prolongated square is illustrated. Discussed are third-order magic squares, fractional magic squares, fifth-order magic squares, decimal magic squares, and even magic squares. (CW)

[Modern magic and medicine].

PubMed

Prokop, O

1975-01-01

In a paper presented on the occasion of the 5th Congress of gynecology in the GDR the author discusses in details the phenomenon of modern occultism and quackery. Preferably he examines the so called parapsychology and declares that this is a field without any scientific value. Therefore the course of action of parapsychologists is not to be accepted without resolute reply.

Pf1 bacteriophage hydration by magic angle spinning solid-state NMR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sergeyev, Ivan V.; Bahri, Salima; McDermott, Ann E., E-mail: aem5@columbia.edu

2014-12-14

High resolution two- and three-dimensional heteronuclear correlation spectroscopy ({sup 1}H–{sup 13}C, {sup 1}H–{sup 15}N, and {sup 1}H–{sup 13}C–{sup 13}C HETCOR) has provided a detailed characterization of the internal and external hydration water of the Pf1 virion. This long and slender virion (2000 nm × 7 nm) contains highly stretched DNA within a capsid of small protein subunits, each only 46 amino acid residues. HETCOR cross-peaks have been unambiguously assigned to 25 amino acids, including most external residues 1–21 as well as residues 39–40 and 43–46 deep inside the virion. In addition, the deoxyribose rings of the DNA near the virionmore » axis are in contact with water. The sets of cross-peaks to the DNA and to all 25 amino acid residues were from the same hydration water {sup 1}H resonance; some of the assigned residues do not have exchangeable side-chain protons. A mapping of the contacts onto structural models indicates the presence of water “tunnels” through a highly hydrophobic region of the capsid. The present results significantly extend and modify results from a lower resolution study, and yield a comprehensive hydration surface map of Pf1. In addition, the internal water could be distinguished from external hydration water by means of paramagnetic relaxation enhancement. The internal water population may serve as a conveniently localized magnetization reservoir for structural studies.« less

Further conventions for NMR shielding and chemical shifts IUPAC recommendations 2008.

PubMed

Harris, Robin K; Becker, Edwin D; Cabral De Menezes, Sonia M; Granger, Pierre; Hoffman, Roy E; Zilm, Kurt W

2008-03-01

IUPAC has published a number of recommendations regarding the reporting of nuclear magnetic resonance (NMR) data, especially chemical shifts. The most recent publication [Pure Appl. Chem. 73, 1795 (2001)] recommended that tetramethylsilane (TMS) serve as a universal reference for reporting the shifts of all nuclides, but it deferred recommendations for several aspects of this subject. This document first examines the extent to which the (1)H shielding in TMS itself is subject to change by variation in temperature, concentration, and solvent. On the basis of recently published results, it has been established that the shielding of TMS in solution [along with that of sodium-3-(trimethylsilyl)propanesulfonate, DSS, often used as a reference for aqueous solutions] varies only slightly with temperature but is subject to solvent perturbations of a few tenths of a part per million (ppm). Recommendations are given for reporting chemical shifts under most routine experimental conditions and for quantifying effects of temperature and solvent variation, including the use of magnetic susceptibility corrections and of magic-angle spinning (MAS). This document provides the first IUPAC recommendations for referencing and reporting chemical shifts in solids, based on high-resolution MAS studies. Procedures are given for relating (13)C NMR chemical shifts in solids to the scales used for high-resolution studies in the liquid phase. The notation and terminology used for describing chemical shift and shielding tensors in solids are reviewed in some detail, and recommendations are given for best practice.

Further conventions for NMR shielding and chemical shifts (IUPAC Recommendations 2008).

PubMed

Harris, Robin K; Becker, Edwin D; De Menezes, Sonia M Cabral; Granger, Pierre; Hoffman, Roy E; Zilm, Kurt W

2008-06-01

IUPAC has published a number of recommendations regarding the reporting of nuclear magnetic resonance (NMR) data, especially chemical shifts. The most recent publication [Pure Appl. Chem. 73, 1795 (2001)] recommended that tetramethylsilane (TMS) serve as a universal reference for reporting the shifts of all nuclides, but it deferred recommendations for several aspects of this subject. This document first examines the extent to which the (1)H shielding in TMS itself is subject to change by variation in temperature, concentration, and solvent. On the basis of recently published results, it has been established that the shielding of TMS in solution [along with that of sodium-3-(trimethylsilyl)propanesulfonate, DSS, often used as a reference for aqueous solutions] varies only slightly with temperature but is subject to solvent perturbations of a few tenths of a part per million (ppm). Recommendations are given for reporting chemical shifts under most routine experimental conditions and for quantifying effects of temperature and solvent variation, including the use of magnetic susceptibility corrections and of magic-angle spinning (MAS). This document provides the first IUPAC recommendations for referencing and reporting chemical shifts in solids, based on high-resolution MAS studies. Procedures are given for relating (13)C NMR chemical shifts in solids to the scales used for high-resolution studies in the liquid phase. The notation and terminology used for describing chemical shift and shielding tensors in solids are reviewed in some detail, and recommendations are given for best practice. Copyright (c) 2008 John Wiley & Sons, Ltd

Nuclear magnetic resonance metabolomics of iron deficiency in soybean leaves.

PubMed

Lima, Marta R M; Diaz, Sílvia O; Lamego, Inês; Grusak, Michael A; Vasconcelos, Marta W; Gil, Ana M

2014-06-06

Iron (Fe) deficiency is an important agricultural concern that leads to lower yields and crop quality. A better understanding of the condition at the metabolome level could contribute to the design of strategies to ameliorate Fe-deficiency problems. Fe-sufficient and Fe-deficient soybean leaf extracts and whole leaves were analyzed by liquid (1)H nuclear magnetic resonance (NMR) and high-resolution magic-angle spinning NMR spectroscopy, respectively. Overall, 30 compounds were measurable and identifiable (comprising amino and organic acids, fatty acids, carbohydrates, alcohols, polyphenols, and others), along with 22 additional spin systems (still unassigned). Thus, metabolite differences between treatment conditions could be evaluated for different compound families simultaneously. Statistically relevant metabolite changes upon Fe deficiency included higher levels of alanine, asparagine/aspartate, threonine, valine, GABA, acetate, choline, ethanolamine, hypoxanthine, trigonelline, and polyphenols and lower levels of citrate, malate, ethanol, methanol, chlorogenate, and 3-methyl-2-oxovalerate. The data indicate that the main metabolic impacts of Fe deficiency in soybean include enhanced tricarboxylic acid cycle activity, enhanced activation of oxidative stress protection mechanisms and enhanced amino acid accumulation. Metabolites showing accumulation differences in Fe-starved but visually asymptomatic leaves could serve as biomarkers for early detection of Fe-deficiency stress.

An HR-MAS MR Metabolomics Study on Breast Tissues Obtained with Core Needle Biopsy

PubMed Central

Cho, Nariya; Chang, Jung Min; Koo, Hye Ryoung; Yi, Ann; Kim, Hyeonjin; Park, Sunghyouk; Moon, Woo Kyung

2011-01-01

Background Much research has been devoted to the development of new breast cancer diagnostic measures, including those involving high-resolution magic angle spinning (HR-MAS) magnetic resonance (MR) spectroscopic techniques. Previous HR-MAS MR results have been obtained from post-surgery samples, which limits their direct clinical applicability. Methodology/Principal Findings In the present study, we performed HR-MAS MR spectroscopic studies on 31 breast tissue samples (13 cancer and 18 non-cancer) obtained by percutaneous core needle biopsy. We showed that cancer and non-cancer samples can be discriminated very well with Orthogonal Projections to Latent Structure-Discriminant Analysis (OPLS-DA) multivariate model on the MR spectra. A subsequent blind test showed 69% sensitivity and 94% specificity in the prediction of the cancer status. A spectral analysis showed that in cancer cells, taurine- and choline-containing compounds are elevated. Our approach, additionally, could predict the progesterone receptor statuses of the cancer patients. Conclusions/Significance HR-MAS MR metabolomics on intact breast tissues obtained by core needle biopsy may have a potential to be used as a complement to the current diagnostic and prognostic measures for breast cancers. PMID:22028780

Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy.

PubMed

Loquet, Antoine; Tolchard, James; Berbon, Melanie; Martinez, Denis; Habenstein, Birgit

2017-09-17

Supramolecular protein assemblies play fundamental roles in biological processes ranging from host-pathogen interaction, viral infection to the propagation of neurodegenerative disorders. Such assemblies consist in multiple protein subunits organized in a non-covalent way to form large macromolecular objects that can execute a variety of cellular functions or cause detrimental consequences. Atomic insights into the assembly mechanisms and the functioning of those macromolecular assemblies remain often scarce since their inherent insolubility and non-crystallinity often drastically reduces the quality of the data obtained from most techniques used in structural biology, such as X-ray crystallography and solution Nuclear Magnetic Resonance (NMR). We here present magic-angle spinning solid-state NMR spectroscopy (SSNMR) as a powerful method to investigate structures of macromolecular assemblies at atomic resolution. SSNMR can reveal atomic details on the assembled complex without size and solubility limitations. The protocol presented here describes the essential steps from the production of 13 C/ 15 N isotope-labeled macromolecular protein assemblies to the acquisition of standard SSNMR spectra and their analysis and interpretation. As an example, we show the pipeline of a SSNMR structural analysis of a filamentous protein assembly.

Distinguishing Polymorphs of the Semiconducting Pigment Copper Phthalocyanine by Solid-state NMR and Raman Spectroscopy

PubMed Central

Shaibat, Medhat A.; Casabianca, Leah B.; Siberio-Pérez, Diana Y.; Matzger, Adam J; Ishii, Yoshitaka

2010-01-01

Cu(II)(phthalocyanine) (CuPc) is broadly utilized as an archetypal molecular semiconductor and is the most widely used blue printing pigment. CuPc crystallizes in six different forms; the chemical and physical properties are substantially modulated by its molecular packing among these polymorphs. Despite the growing importance of this system, spectroscopic identification of different polymorphs for CuPc has posed difficulties. This study presents the first example of spectroscopic distinction of α- and β-forms of CuPc, the most widely used polymorphs, by solid-state NMR (SSNMR) and Raman spectroscopy. 13C high-resolution SSNMR spectra of α- and β-CuPc using very-fast magic angle spinning (VFMAS) at 20 kHz show that hyperfine shifts sensitively reflect polymorphs of CuPc. The experimental results were confirmed by ab initio chemical shift calculations. 13C and 1H SSNMR relaxation times of α- and β-CuPc under VFMAS also showed marked differences, presumably because of the difference in electronic spin correlation times in the two forms. Raman spectroscopy also provided another reliable method of differentiation between the two polymorphs. PMID:20225842

Evidence for cross-linking in tomato cutin using HR-MAS NMR spectroscopy.

PubMed

Deshmukh, Ashish P; Simpson, André J; Hatcher, Patrick G

2003-11-01

Cutin is a polyester biopolymer component of plant leaf and fruit cuticles, most often associated with waxes and cuticular polysaccharides, and sometimes with another aliphatic biopolymer called cutan. Insolubility of these cuticular biopolymers has made it difficult to apply traditional analytical techniques for structure determination, because most techniques providing molecular level details require solubility. By using the relatively new technique of one and two-dimensional high-resolution magic angle spinning (HR-MAS) NMR spectroscopy, with added information from solid-state 13C NMR spectroscopy, detailed through-bond connectivities and assignments are made for cutin from Lycopersicon esculentum (tomato) fruit. Based on the data obtained, tomato cutin is found to be predominantly an aliphatic polyester with some olefinic and aromatic moieties, consistent with previous studies that employed various degradative approaches. Aside from esters, there are free primary and secondary alcohol groups, as well as free fatty acids. A significant finding is the presence of alpha-branched fatty acids/esters. Mid-chain hydroxyls appear to be generally unesterified, but esters of mid-chain hydroxyls have been identified. The alpha-branched fatty acids/esters and esters of mid-chain hydroxyls could point towards cross-linking.

Genetic algorithm optimized triply compensated pulses in NMR spectroscopy

NASA Astrophysics Data System (ADS)

Manu, V. S.; Veglia, Gianluigi

2015-11-01

Sensitivity and resolution in NMR experiments are affected by magnetic field inhomogeneities (of both external and RF), errors in pulse calibration, and offset effects due to finite length of RF pulses. To remedy these problems, built-in compensation mechanisms for these experimental imperfections are often necessary. Here, we propose a new family of phase-modulated constant-amplitude broadband pulses with high compensation for RF inhomogeneity and heteronuclear coupling evolution. These pulses were optimized using a genetic algorithm (GA), which consists in a global optimization method inspired by Nature's evolutionary processes. The newly designed π and π / 2 pulses belong to the 'type A' (or general rotors) symmetric composite pulses. These GA-optimized pulses are relatively short compared to other general rotors and can be used for excitation and inversion, as well as refocusing pulses in spin-echo experiments. The performance of the GA-optimized pulses was assessed in Magic Angle Spinning (MAS) solid-state NMR experiments using a crystalline U-13C, 15N NAVL peptide as well as U-13C, 15N microcrystalline ubiquitin. GA optimization of NMR pulse sequences opens a window for improving current experiments and designing new robust pulse sequences.

Further refinement of 17O TRAPDOR NMR methods for determining oxygen speciation in multi-component oxide glasses

NASA Astrophysics Data System (ADS)

LaComb, M.; Stebbins, J. F.

2017-12-01

Solid state nuclear magnetic resonance (NMR) spectroscopy has often been utilized to determine network speciation in oxide glasses, typically using NMR-active nuclides such as 11B, 27Al and 17O. High field strength magnets allow for visible separation between bridging (BO) and non-bridging oxygens (NBO) in 17O magic-angle spinning (MAS) NMR spectra, but many questions remain due to limited ability to directly observe NBO associated with silicon, boron or aluminum in ternary glass systems with MAS NMR techniques. Recent studies have utilized the combination of 17O{27Al} and 17O{11B} TRAnsfer of Population in DOuble-Resonance (TRAPDOR) NMR to attempt to separate out resonances for these different bridging and non-bridging oxygen species in multicomponent calcium aluminosilicate and aluminoborosilicate glasses and rare-earth aluminoborosilicates. With improved technology and better resolution of spectral components we were able to expand this study to a wider range of calcium aluminosilicate, aluminoborate and aluminoborosilicate glasses and further separate out resonances for both bridging and non-bridging oxygens coordinated with aluminum, boron and/or silicon cations in these glasses.

A ultra-small-angle self-mixing sensor system with high detection resolution and wide measurement range

NASA Astrophysics Data System (ADS)

Yang, Bo; Wang, Dehui; Zhou, Lin; Wu, Shuang; Xiang, Rong; Zhang, Wenhua; Gui, Huaqiao; Liu, Jianguo; Wang, Huanqing; Lu, Liang; Yu, Benli

2017-06-01

The self-mixing technique based on the traditional reflecting mirror has been demonstrated with great merit for angle sensing applications. Here we demonstrate a modified self-reflection-mixing angle measurement system by combine a right-angle prism to self-mixing angle measurement. In our system, the wavelength is crucial to the angle measurement resolution. For a microchip solid-state laser, the measurement resolution can reach 0.49 mrad, while the resolution for the He-Ne laser is 0.53 mrad. In addition, the ranges in the system with the microchip solid-state laser and He-Ne laser are up to 22 mrad and 24.9 mrad respectively. This modified angle measurement system effectively combines the advantage of self-mixing measurement system with a compact structure, providing interesting features such as of high requisition of resolution and precision.

Monte Carlo-based assessment of the trade-off between spatial resolution, field-of-view and scattered radiation in the variable resolution X-ray CT scanner.

PubMed

Arabi, Hossein; Kamali Asl, Ali Reza; Ay, Mohammad Reza; Zaidi, Habib

2015-07-01

The purpose of this work is to evaluate the impact of optimization of magnification on performance parameters of the variable resolution X-ray (VRX) CT scanner. A realistic model based on an actual VRX CT scanner was implemented in the GATE Monte Carlo simulation platform. To evaluate the influence of system magnification, spatial resolution, field-of-view (FOV) and scatter-to-primary ratio of the scanner were estimated for both fixed and optimum object magnification at each detector rotation angle. Comparison and inference between these performance parameters were performed angle by angle to determine appropriate object position at each opening half angle. Optimization of magnification resulted in a trade-off between spatial resolution and FOV of the scanner at opening half angles of 90°-12°, where the spatial resolution increased up to 50% and the scatter-to-primary ratio decreased from 4.8% to 3.8% at a detector angle of about 90° for the same FOV and X-ray energy spectrum. The disadvantage of magnification optimization at these angles is the significant reduction of the FOV (up to 50%). Moreover, magnification optimization was definitely beneficial for opening half angles below 12° improving the spatial resolution from 7.5 cy/mm to 20 cy/mm. Meanwhile, the FOV increased by more than 50% at these angles. It can be concluded that optimization of magnification is essential for opening half angles below 12°. For opening half angles between 90° and 12°, the VRX CT scanner magnification should be set according to the desired spatial resolution and FOV. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Ultrafast VHE Gamma-Ray Flares of IC 310

NASA Astrophysics Data System (ADS)

Barkov, Maxim V.; Aharonian, Felix; Khangulyan, Dmitriy V.

In 2012 November MAGIC detected a bright flare from IC 310. The flare consisted of two sharp peaks with a typical duration of ~ 5 min. The energy released during that event has been estimated to be at the level of 2 × 1044 erg s-1. In this work we derive an upper limit on the possible luminosity of flares generated in black hole (BH) magnetosphere, which depends very weakly on the mass of BH and is determined by disk magnetisation, viewing angle, and pair multiplicity. Since all these parameters are smaller than a unit, the luminosity 2 × 1043 erg s-1 can be taken as a strict upper limit for flare luminosity for several minutes variability time. This upper limit appears to be approximately an order of magnitude below the value measured with MAGIC. Thus, we conclude that it seems very unfeasible that the magnetospheric processes can be indeed behind the bright flaring activity recorded from IC 310.

MAGIC with formaldehyde applied to dosimetry of HDR brachytherapy source

NASA Astrophysics Data System (ADS)

Marques; T; Fernandes; J; Barbi; G; Nicolucci; P; Baffa; O

2009-05-01

The use of polymer gel dosimeters in brachytherapy can allow the determination of three-dimensional dose distributions in large volumes and with high spatial resolution if an adequate calibration process is performed. One of the major issues in these experiments is the polymer gel response dependence on dose rate when high dose rate sources are used and the doses in the vicinity of the sources are to be determinated. In this study, the response of a modified MAGIC polymer gel with formaldehyde around an Iridium-192 HDR brachytherapy source is presented. Experimental results obtained with this polymer gel were compared with ionization chamber measurements and with Monte Carlo simulation with PENELOPE. A maximum difference of 3.10% was found between gel dose measurements and Monte Carlo simulation at a radial distance of 18 mm from the source. The results obtained show that the gel's response is strongly influenced by dose rate and that a different calibration should be used for the vicinity of the source and for regions of lower dose rates. The results obtained in this study show that, provided the proper calibration is performed, MAGIC with formaldehyde can be successfully used to accurate determinate dose distributions form high dose rate brachytherapy sources.

Identification of tert-Butyl Cations in Zeolite H-ZSM-5: Evidence from NMR Spectroscopy and DFT Calculations.

PubMed

Dai, Weili; Wang, Chuanming; Yi, Xianfeng; Zheng, Anmin; Li, Landong; Wu, Guangjun; Guan, Naijia; Xie, Zaiku; Dyballa, Michael; Hunger, Michael

2015-07-20

Experimental evidence for the presence of tert-butyl cations, which are important intermediates in acid-catalyzed heterogeneous reactions, on solid acids has still not been provided to date. By combining density functional theory (DFT) calculations with (1)H/(13)C magic-angle-spinning NMR spectroscopy, the tert-butyl cation was successfully identified on zeolite H-ZSM-5 upon conversion of isobutene by capturing this intermediate with ammonia. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Yanyan

This thesis describes application and development of advanced solid-state nuclear magnetic resonance techniques for complex materials, in particular organic-inorganic nanocomposites and thermoelectric tellurides. The apatite-collagen interface, essential for understanding the biomineralization process in bone and engineering the interface for controlled bio-mimetic synthesis and optimized mechanical properties, is buried within the nanocomposite of bone. We used multinuclear solid-state NMR to study the composition and structure of the interface. Citrate has been identified as the main organic molecule strongly bound to the apatite surface with a density of 1/(2 nm) 2, covering 1/6 of the total surface area in bovine bone. Citratemore » provides more carboxylate groups, one of the key functional groups found to affect apatite nucleation and growth, than all the non-collagenous proteins all together in bone; thus we propose that citrate stabilizes apatite crystals at a very small thickness of ~3 nm (4 unit cells) to increase bone fracture tolerance. The hypothesis has been confirmed in vitro by adding citrate in the bio-mimetic synthesis of polymerhydroxyapatite nanocomposites. The results have shown that the size of hydroxyapatite nanocrystals decreases as increasing citrate concentration. With citrate concentrations comparable to that in body fluids, similar-sized nanocrystals as in bone have been produced. Besides the dimensions of the apatite crystals, the composition of bone also affects its biofunctional and macroscopic mechanical properties; therefore, our team also extended its effort to enhance the inorganic portion in our bio-mimetic synthesis from originally 15 wt% to current 50 wt% compared to 65 wt% in bovine bone, by using Lysine-Leucine hydroxyapatite nucleating diblock co-polypeptide, which forms a gel at very low concentration. In this thesis, various advanced solid state NMR techniques have been employed to characterize nanocomposites. Meanwhile, we have developed new methods to achieve broadband high resolution NMR and improve the accuracy of inter-nuclear distance measurements involving quadrupolar spins. Broadband high resolution NMR of spin-1/2 nuclei has been accomplished by the adaptation of the magic angle turning (MAT) method to fast magic angle spinning, termed fast MAT, by solving technical problems such as off resonance effects. Fast MAT separates chemical shift anisotropy and isotropic chemical shifts over a spectral range of ~1.8 γB 1 without significant distortions. Fast MAT 125Te NMR has been applied to study technologically important telluride materials with spectra spreading up to 190 kHz. The signal-to-noise ratio of the spectra is significantly improved by using echo-matched Gaussian filtering in offline data processing. The accuracy of the measured distances between spin-1/2 and quadrupolar nuclei with methods such as SPIDER and REAPDOR has been improved by compensating for the fast longitudinal quadrupolar relaxation on the sub-millisecond with a modified S 0 pulse sequence. Also, the T1Q effect on the spin coherence and its spinning speed dependency has been explored and documented with analytical and numerical simulations as well as experimental measurements.« less

Optimized multiple quantum MAS lineshape simulations in solid state NMR

NASA Astrophysics Data System (ADS)

Brouwer, William J.; Davis, Michael C.; Mueller, Karl T.

2009-10-01

The majority of nuclei available for study in solid state Nuclear Magnetic Resonance have half-integer spin I>1/2, with corresponding electric quadrupole moment. As such, they may couple with a surrounding electric field gradient. This effect introduces anisotropic line broadening to spectra, arising from distinct chemical species within polycrystalline solids. In Multiple Quantum Magic Angle Spinning (MQMAS) experiments, a second frequency dimension is created, devoid of quadrupolar anisotropy. As a result, the center of gravity of peaks in the high resolution dimension is a function of isotropic second order quadrupole and chemical shift alone. However, for complex materials, these parameters take on a stochastic nature due in turn to structural and chemical disorder. Lineshapes may still overlap in the isotropic dimension, complicating the task of assignment and interpretation. A distributed computational approach is presented here which permits simulation of the two-dimensional MQMAS spectrum, generated by random variates from model distributions of isotropic chemical and quadrupole shifts. Owing to the non-convex nature of the residual sum of squares (RSS) function between experimental and simulated spectra, simulated annealing is used to optimize the simulation parameters. In this manner, local chemical environments for disordered materials may be characterized, and via a re-sampling approach, error estimates for parameters produced. Program summaryProgram title: mqmasOPT Catalogue identifier: AEEC_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEEC_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 3650 No. of bytes in distributed program, including test data, etc.: 73 853 Distribution format: tar.gz Programming language: C, OCTAVE Computer: UNIX/Linux Operating system: UNIX/Linux Has the code been vectorised or parallelized?: Yes RAM: Example: (1597 powder angles) × (200 Samples) × (81 F2 frequency pts) × (31 F1 frequency points) = 3.5M, SMP AMD opteron Classification: 2.3 External routines: OCTAVE ( http://www.gnu.org/software/octave/), GNU Scientific Library ( http://www.gnu.org/software/gsl/), OPENMP ( http://openmp.org/wp/) Nature of problem: The optimal simulation and modeling of multiple quantum magic angle spinning NMR spectra, for general systems, especially those with mild to significant disorder. The approach outlined and implemented in C and OCTAVE also produces model parameter error estimates. Solution method: A model for each distinct chemical site is first proposed, for the individual contribution of crystallite orientations to the spectrum. This model is averaged over all powder angles [1], as well as the (stochastic) parameters; isotropic chemical shift and quadrupole coupling constant. The latter is accomplished via sampling from a bi-variate Gaussian distribution, using the Box-Muller algorithm to transform Sobol (quasi) random numbers [2]. A simulated annealing optimization is performed, and finally the non-linear jackknife [3] is applied in developing model parameter error estimates. Additional comments: The distribution contains a script, mqmasOpt.m, which runs in the OCTAVE language workspace. Running time: Example: (1597 powder angles) × (200 Samples) × (81 F2 frequency pts) × (31 F1 frequency points) = 58.35 seconds, SMP AMD opteron. References:S.K. Zaremba, Annali di Matematica Pura ed Applicata 73 (1966) 293. H. Niederreiter, Random Number Generation and Quasi-Monte Carlo Methods, SIAM, 1992. T. Fox, D. Hinkley, K. Larntz, Technometrics 22 (1980) 29.

Improving the resolution in proton-detected through-space heteronuclear multiple quantum correlation NMR spectroscopy.

PubMed

Shen, Ming; Trébosc, J; Lafon, O; Pourpoint, F; Hu, Bingwen; Chen, Qun; Amoureux, J-P

2014-08-01

Connectivities and proximities between protons and low-gamma nuclei can be probed in solid-state NMR spectroscopy using two-dimensional (2D) proton-detected heteronuclear correlation, through Heteronuclear Multiple Quantum Correlation (HMQC) pulse sequence. The indirect detection via protons dramatically enhances the sensitivity. However, the spectra are often broadened along the indirect F1 dimension by the decay of heteronuclear multiple-quantum coherences under the strong (1)H-(1)H dipolar couplings. This work presents a systematic comparison of the performances of various decoupling schemes during the indirect t1 evolution period of dipolar-mediated HMQC (D-HMQC) experiment. We demonstrate that (1)H-(1)H dipolar decoupling sequences during t1, such as symmetry-based schemes, phase-modulated Lee-Goldburg (PMLG) and Decoupling Using Mind-Boggling Optimization (DUMBO), provide better resolution than continuous wave (1)H irradiation. We also report that high resolution requires the preservation of (1)H isotropic chemical shifts during the decoupling sequences. When observing indirectly broad spectra presenting numerous spinning sidebands, the D-HMQC sequence must be fully rotor-synchronized owing to the rotor-synchronized indirect sampling and dipolar recoupling sequence employed. In this case, we propose a solution to reduce artefact sidebands caused by the modulation of window delays before and after the decoupling application during the t1 period. Moreover, we show that (1)H-(1)H dipolar decoupling sequence using Smooth Amplitude Modulation (SAM) minimizes the t1-noise. The performances of the various decoupling schemes are assessed via numerical simulations and compared to 2D (1)H-{(13)C} D-HMQC experiments on [U-(13)C]-L-histidine⋅HCl⋅H2O at various magnetic fields and Magic Angle spinning (MAS) frequencies. Great resolution and sensitivity enhancements resulting from decoupling during t1 period enable the detection of heteronuclear correlation between aliphatic protons and ammonium (14)N sites in L-histidine⋅HCl⋅H2O. Copyright © 2014 Elsevier Inc. All rights reserved.

Powder-XRD and (14) N magic angle-spinning solid-state NMR spectroscopy of some metal nitrides.

PubMed

Kempgens, Pierre; Britton, Jonathan

2016-05-01

Some metal nitrides (TiN, ZrN, InN, GaN, Ca3 N2 , Mg3 N2 , and Ge3 N4 ) have been studied by powder X-ray diffraction (XRD) and (14) N magic angle-spinning (MAS) solid-state NMR spectroscopy. For Ca3 N2 , Mg3 N2 , and Ge3 N4 , no (14) N NMR signal was observed. Low speed (νr  = 2 kHz for TiN, ZrN, and GaN; νr  = 1 kHz for InN) and 'high speed' (νr  = 15 kHz for TiN; νr  = 5 kHz for ZrN; νr  = 10 kHz for InN and GaN) MAS NMR experiments were performed. For TiN, ZrN, InN, and GaN, powder-XRD was used to identify the phases present in each sample. The number of peaks observed for each sample in their (14) N MAS solid-state NMR spectrum matches perfectly well with the number of nitrogen-containing phases identified by powder-XRD. The (14) N MAS solid-state NMR spectra are symmetric and dominated by the quadrupolar interaction. The envelopes of the spinning sidebands manifold are Lorentzian, and it is concluded that there is a distribution of the quadrupolar coupling constants Qcc 's arising from structural defects in the compounds studied. Copyright © 2015 John Wiley & Sons, Ltd.

Radiofrequency fields in MAS solid state NMR probes

NASA Astrophysics Data System (ADS)

Tošner, Zdeněk; Purea, Armin; Struppe, Jochem O.; Wegner, Sebastian; Engelke, Frank; Glaser, Steffen J.; Reif, Bernd

2017-11-01

We present a detailed analysis of the radiofrequency (RF) field over full volume of a rotor that is generated in a solenoid coil. On top of the usually considered static distribution of amplitudes along the coil axis we describe dynamic radial RF inhomogeneities induced by sample rotation. During magic angle spinning (MAS), the mechanical rotation of the sample about the magic angle, a spin packet travels through areas of different RF fields and experiences periodical modulations of both the RF amplitude and the phase. These modulations become particularly severe at the end regions of the coil where the relative RF amplitude varies up to ±25% and the RF phase changes within ±30°. Using extensive numerical simulations we demonstrate effects of RF inhomogeneity on pulse calibration and for the ramped CP experiment performed at a wide range of MAS rates. In addition, we review various methods to map RF fields using a B0 gradient along the sample (rotor axis) for imaging purposes. Under such a gradient, a nutation experiment provides directly the RF amplitude distribution, a cross polarization experiment images the correlation of the RF fields on the two channels according to the Hartmann-Hahn matching condition, while a spin-lock experiment allows to calibrate the RF amplitude employing the rotary resonance recoupling condition. Knowledge of the RF field distribution in a coil provides key to understand its effects on performance of a pulse sequence at the spectrometer and enables to set robustness requirements in the experimental design.

The use of a selective saturation pulse to suppress t1 noise in two-dimensional (1)H fast magic angle spinning solid-state NMR spectroscopy.

PubMed

Robertson, Aiden J; Pandey, Manoj Kumar; Marsh, Andrew; Nishiyama, Yusuke; Brown, Steven P

2015-11-01

A selective saturation pulse at fast magic angle spinning (MAS) frequencies (60+kHz) suppresses t1 noise in the indirect dimension of two-dimensional (1)H MAS NMR spectra. The method is applied to a synthetic nucleoside with an intense methyl (1)H signal due to triisopropylsilyl (TIPS) protecting groups. Enhanced performance in terms of suppressing the methyl signal while minimising the loss of signal intensity of nearby resonances of interest relies on reducing spin diffusion--this is quantified by comparing two-dimensional (1)H NOESY-like spin diffusion spectra recorded at 30-70 kHz MAS. For a saturation pulse centred at the methyl resonance, the effect of changing the nutation frequency at different MAS frequencies as well as the effect of changing the pulse duration is investigated. By applying a pulse of duration 30 ms and nutation frequency 725 Hz at 70 kHz MAS, a good compromise of significant suppression of the methyl resonance combined with the signal intensity of resonances greater than 5 ppm away from the methyl resonance being largely unaffected is achieved. The effectiveness of using a selective saturation pulse is demonstrated for both homonuclear (1)H-(1)H double quantum (DQ)/single quantum (SQ) MAS and (14)N-(1)H heteronuclear multiple quantum coherence (HMQC) two-dimensional solid-state NMR experiments. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Theory for cross effect dynamic nuclear polarization under magic-angle spinning in solid state nuclear magnetic resonance: the importance of level crossings.

PubMed

Thurber, Kent R; Tycko, Robert

2012-08-28

We present theoretical calculations of dynamic nuclear polarization (DNP) due to the cross effect in nuclear magnetic resonance under magic-angle spinning (MAS). Using a three-spin model (two electrons and one nucleus), cross effect DNP with MAS for electron spins with a large g-anisotropy can be seen as a series of spin transitions at avoided crossings of the energy levels, with varying degrees of adiabaticity. If the electron spin-lattice relaxation time T(1e) is large relative to the MAS rotation period, the cross effect can happen as two separate events: (i) partial saturation of one electron spin by the applied microwaves as one electron spin resonance (ESR) frequency crosses the microwave frequency and (ii) flip of all three spins, when the difference of the two ESR frequencies crosses the nuclear frequency, which transfers polarization to the nuclear spin if the two electron spins have different polarizations. In addition, adiabatic level crossings at which the two ESR frequencies become equal serve to maintain non-uniform saturation across the ESR line. We present analytical results based on the Landau-Zener theory of adiabatic transitions, as well as numerical quantum mechanical calculations for the evolution of the time-dependent three-spin system. These calculations provide insight into the dependence of cross effect DNP on various experimental parameters, including MAS frequency, microwave field strength, spin relaxation rates, hyperfine and electron-electron dipole coupling strengths, and the nature of the biradical dopants.

Glycerin-Induced Conformational Changes in Bombyx mori Silk Fibroin Film Monitored by (13)C CP/MAS NMR and ¹H DQMAS NMR.

PubMed

Asakura, Tetsuo; Endo, Masanori; Hirayama, Misaki; Arai, Hiroki; Aoki, Akihiro; Tasei, Yugo

2016-09-09

In order to improve the stiff and brittle characteristics of pure Bombyx mori (B. mori) silk fibroin (SF) film in the dry state, glycerin (Glyc) has been used as a plasticizer. However, there have been very limited studies on the structural characterization of the Glyc-blended SF film. In this study, (13)C Cross Polarization/Magic Angle Spinning nuclear magnetic resonance (CP/MAS NMR) was used to monitor the conformational changes in the films by changing the Glyc concentration. The presence of only 5 wt % Glyc in the film induced a significant conformational change in SF where Silk I* (repeated type II β-turn and no α-helix) newly appeared. Upon further increase in Glyc concentration, the percentage of Silk I* increased linearly up to 9 wt % Glyc and then tended to be almost constant (30%). This value (30%) was the same as the fraction of Ala residue within the Silk I* form out of all Ala residues of SF present in B. mori mature silkworm. The ¹H DQMAS NMR spectra of Glyc-blended SF films confirmed the appearance of Silk I* in the Glyc-blended SF film. A structural model of Glyc-SF complex including the Silk I* form was proposed with the guidance of the Molecular Dynamics (MD) simulation using ¹H-¹H distance constraints obtained from the ¹H Double-Quantum Magic Angle Spinning (DQMAS) NMR spectra.

Accurate determination of chemical shift tensor orientations of single-crystals by solid-state magic angle spinning NMR

NASA Astrophysics Data System (ADS)

Avadhut, Yamini S.; Weber, Johannes; Schmedt auf der Günne, Jörn

2017-09-01

An improved implementation of single-crystal magic-angle-spinning (MAS) NMR is presented which gives access to chemical shift tensors both in orientation (relative to the crystal axis system) and principal axis values. For mounting arbitrary crystals inside ordinary MAS rotors, a mounting tool is described which allows to relate the crystal orientation determined by diffraction techniques to the rotor coordinate system. The crystal is finally mounted into a MAS rotor equipped with a special insert which allows a defined reorientation of the single-crystal by 90°. The approach is based on the idea that the dispersive spectra, which are obtained when applying read-pulses at specific rotor-phases, not only yield the size of the eigenvalues but also encode the orientation of the different chemical shift (rank-2) tensors. For this purpose two 2D-data sets with orthogonal crystal orientation are fitted simultaneously. The presented analysis for chemical shift tensors is supported by an analytical formula which allows fast calculation of phase and amplitude of individual spinning side-bands and by a protocol which solves the problem of finding the correct reference phase of the spectrum. Different rotor-synchronized pulse-sequences are introduced for the same reason. Experiments are performed on L-alanine and O-phosphorylethanolamine and the observed errors are analyzed in detail. The experimental data are opposed to DFT-computed chemical shift tensors which have been obtained by the extended embedded ion method.

A robust heteronuclear dipolar recoupling method comparable to TEDOR for proteins in magic-angle spinning solid-state NMR

NASA Astrophysics Data System (ADS)

Zhang, Zhengfeng; Li, Jianping; Chen, Yanke; Xie, Huayong; Yang, Jun

2017-12-01

In this letter, we propose a robust heteronuclear dipolar recoupling method for proteins in magic-angle spinning (MAS) solid-state NMR. This method is as simple, robust and efficient as the well-known TEDOR in the aspect of magnetization transfer between 15N and 13C. Deriving from our recent band-selective dual back-to-back pulses (DBP) (Zhang et al., 2016), this method uses new phase-cycling schemes to realize broadband DBP (Bro-DBP). For broadband 15N-13C magnetization transfer (simultaneous 15N → 13C‧ and 15N → 13Cα), Bro-DBP has almost the same 15N → 13Cα efficiency while offers 30-40% enhancement on 15N → 13C‧ transfer, compared to TEDOR. Besides, Bro-DBP can also be used as a carbonyl (13C‧)-selected method, whose 15N → 13C‧ efficiency is up to 1.7 times that of TEDOR and is also higher than that of band-selective DBP. The performance of Bro-DBP is demonstrated on the N-formyl-[U-13C,15N]-Met-Leu-Phe-OH (fMLF) peptide and the U-13C, 15N labeled β1 immunoglobulin binding domain of protein G (GB1) microcrystalline protein. Since Bro-DBP is as robust, simple and efficient as TEDOR, we believe it is very useful for protein studies in MAS solid-state NMR.

High zenith angle observations of PKS 2155-304 with the MAGIC-I telescope

NASA Astrophysics Data System (ADS)

Aleksić, J.; Alvarez, E. A.; Antonelli, L. A.; Antoranz, P.; Asensio, M.; Backes, M.; Barres de Almeida, U.; Barrio, J. A.; Bastieri, D.; Becerra González, J.; Bednarek, W.; Berdyugin, A.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Boller, A.; Bonnoli, G.; Borla Tridon, D.; Braun, I.; Bretz, T.; Cañellas, A.; Carmona, E.; Carosi, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Cossio, L.; Covino, S.; Dazzi, F.; De Angelis, A.; De Caneva, G.; De Cea del Pozo, E.; De Lotto, B.; Delgado Mendez, C.; Diago Ortega, A.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Eisenacher, D.; Elsaesser, D.; Ferenc, D.; Fonseca, M. V.; Font, L.; Fruck, C.; García López, R. J.; Garczarczyk, M.; Garrido, D.; Giavitto, G.; Godinović, N.; Gozzini, S. R.; Hadasch, D.; Häfner, D.; Herrero, A.; Hildebrand, D.; Höhne-Mönch, D.; Hose, J.; Hrupec, D.; Jogler, T.; Kellermann, H.; Klepser, S.; Krähenbühl, T.; Krause, J.; Kushida, J.; La Barbera, A.; Lelas, D.; Leonardo, E.; Lewandowska, N.; Lindfors, E.; Lombardi, S.; López, M.; López, R.; López-Oramas, A.; Lorenz, E.; Makariev, M.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Marcote, B.; Mariotti, M.; Martínez, M.; Mazin, D.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Moldón, J.; Moralejo, A.; Munar-Adrover, P.; Niedzwiecki, A.; Nieto, D.; Nilsson, K.; Nowak, N.; Orito, R.; Paiano, S.; Paneque, D.; Paoletti, R.; Pardo, S.; Paredes, J. M.; Partini, S.; Perez-Torres, M. A.; Persic, M.; Peruzzo, L.; Pilia, M.; Pochon, J.; Prada, F.; Prada Moroni, P. G.; Prandini, E.; Puerto Gimenez, I.; Puljak, I.; Reichardt, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Rügamer, S.; Saggion, A.; Saito, K.; Saito, T. Y.; Salvati, M.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shayduk, M.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Spanier, F.; Spiro, S.; Stamatescu, V.; Stamerra, A.; Steinke, B.; Storz, J.; Strah, N.; Sun, S.; Surić, T.; Takalo, L.; Takami, H.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Tibolla, O.; Torres, D. F.; Treves, A.; Uellenbeck, M.; Vankov, H.; Vogler, P.; Wagner, R. M.; Weitzel, Q.; Zabalza, V.; Zandanel, F.; Zanin, R.

2012-08-01

Context. The high frequency peaked BL Lac PKS 2155-304 with a redshift of z = 0.116 was discovered in 1997 in the very high energy (VHE, E > 100 GeV) γ-ray range by the University of Durham Mark VI γ-ray Cherenkov telescope in Australia with a flux corresponding to 20% of the Crab Nebula flux. It was later observed and detected with high significance by the southern Cherenkov observatory H.E.S.S. establishing this source as the best studied southern TeV blazar. Detection from the northern hemisphere is difficult due to challenging observation conditions under large zenith angles. In July 2006, the H.E.S.S. collaboration reported an extraordinary outburst of VHE γ-emission. During the outburst, the VHE γ-ray emission was found to be variable on the time scales of minutes and with a mean flux of ~7 times the flux observed from the Crab Nebula. Follow-up observations with the MAGIC-I standalone Cherenkov telescope were triggered by this extraordinary outburst and PKS 2155-304 was observed between 28 July to 2 August 2006 for 15 h at large zenith angles. Aims: We studied the behavior of the source after its extraordinary flare. Furthermore, we developed an analysis method in order to analyze these data taken under large zenith angles. Methods: Here we present an enhanced analysis method for data taken at high zenith angles. We developed improved methods for event selection that led to a better background suppression. Results: The quality of the results presented here is superior to the results presented previously for this data set: detection of the source on a higher significance level and a lower analysis threshold. The averaged energy spectrum we derived has a spectral index of (-3.5 ± 0.2) above 400 GeV, which is in good agreement with the spectral shape measured by H.E.S.S. during the major flare on MJD 53 944. Furthermore, we present the spectral energy distribution modeling of PKS 2155-304. With our observations we increased the duty cycle of the source extending the light curve derived by H.E.S.S. after the outburst. Finally, we find night-by-night variability with a maximal amplitude of a factor three to four and an intranight variability in one of the nights (MJD 53 945) with a similar amplitude.

Muon tomography imaging improvement using optimized limited angle data

NASA Astrophysics Data System (ADS)

Bai, Chuanyong; Simon, Sean; Kindem, Joel; Luo, Weidong; Sossong, Michael J.; Steiger, Matthew

2014-05-01

Image resolution of muon tomography is limited by the range of zenith angles of cosmic ray muons and the flux rate at sea level. Low flux rate limits the use of advanced data rebinning and processing techniques to improve image quality. By optimizing the limited angle data, however, image resolution can be improved. To demonstrate the idea, physical data of tungsten blocks were acquired on a muon tomography system. The angular distribution and energy spectrum of muons measured on the system was also used to generate simulation data of tungsten blocks of different arrangement (geometry). The data were grouped into subsets using the zenith angle and volume images were reconstructed from the data subsets using two algorithms. One was a distributed PoCA (point of closest approach) algorithm and the other was an accelerated iterative maximal likelihood/expectation maximization (MLEM) algorithm. Image resolution was compared for different subsets. Results showed that image resolution was better in the vertical direction for subsets with greater zenith angles and better in the horizontal plane for subsets with smaller zenith angles. The overall image resolution appeared to be the compromise of that of different subsets. This work suggests that the acquired data can be grouped into different limited angle data subsets for optimized image resolution in desired directions. Use of multiple images with resolution optimized in different directions can improve overall imaging fidelity and the intended applications.

Magic Angle Spinning NMR Metabolomics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhi Hu, Jian

Nuclear Magnetic Resonance (NMR) spectroscopy is a non-destructive, quantitative, reproducible, untargeted and unbiased method that requires no or minimal sample preparation, and is one of the leading analytical tools for metabonomics research [1-3]. The easy quantification and the no need of prior knowledge about compounds present in a sample associated with NMR are advantageous over other techniques [1,4]. 1H NMR is especially attractive because protons are present in virtually all metabolites and its NMR sensitivity is high, enabling the simultaneous identification and monitoring of a wide range of low molecular weight metabolites.

Solid-state NMR and computational studies of 4-methyl-2-nitroacetanilide.

PubMed

Harris, Robin K; Ghi, Phuong Y; Hammond, Robert B; Ma, Cai Yun; Roberts, Kevin J; Yates, Jonathan R; Pickard, Chris J

2006-03-01

Studies on the solid-state structure of two polymorphs of 4-methyl-2-nitroacetanilide (MNA) were conducted using magic-angle spinning (13)C, (15)N and (1)H NMR spectroscopy, together with first-principles computations of NMR shielding (including use of a program that takes explicit account of the translational symmetry inherent in crystalline structures). The effects on (13)C chemical shifts of side-chain rotations have been explored. Information derived from these studies was then incorporated within a systematic space-search methodology for elucidation of trial crystallographic structures from powder XRD.

13C CP MAS NMR and GIAO-CHF calculations of coumarins.

PubMed

Zolek, Teresa; Paradowska, Katarzyna; Wawer, Iwona

2003-01-01

13C cross-polarization magic-angle spinning NMR spectra were recorded for a series of solid coumarins. Ab initio calculations of shielding constants were performed with the use of GIAO-CHF method. The combined CPMAS NMR and theoretical approach was successful in characterizing solid-state conformations of coumarins; a relationship sigma (ppm) = -1.032 xdelta + 205.28 (R(2) = 0.9845) can be used to obtain structural information for coumarins, for which solid-state NMR or crystal structure data are not available. Copyright 2002 Elsevier Science (USA)

On the origin of high ionic conductivity in Na-doped SrSiO 3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chien, Po-Hsiu; Jee, Youngseok; Huang, Chen

Understanding the local structure and ion dynamics is at the heart of ion conductor research. This paper reports on high-resolution solid-state 29Si, 23Na, and 17O NMR investigation of the structure, chemical composition, and ion dynamics of a newly discovered fast ion conductor, Na-doped SrSiO 3, which exhibited a much higher ionic conductivity than most of current oxide ion conductors. Quantitative analyses reveal that with a small dose (<10 mol%) of Na, the doped Na integrates into the SrSiO 3 structure to form Na xSr 1-xSiO 3-0.5x, and with >10 mol% Na doping, phase separation occurs, leading to the formation ofmore » an amorphous phase β-Na 2Si 2O 5 and a crystalline Sr-rich phase. Variable-temperature 23Na and 17O magic-angle-spinning NMR up to 618 °C have shown significant changes in Na ion dynamics at high temperatures but little oxide ion motion, suggesting that Na ions are responsible for the observed high ionic conductivity. In addition, β-Na 2Si 2O 5 starts to crystallize at temperatures higher than 480 °C with prolonged heating, resulting in reduction in Na+ motion, and thus degradation of ionic conductivity. This study has contributed critical evidence to the understanding of ionic conduction in Na-doped SrSiO 3 and demonstrated that multinuclear high-resolution and high-temperature solid-state NMR is a uniquely useful tool for investigating ion conductors at their operating conditions.« less

Applications of high-resolution 1H solid-state NMR.

PubMed

Brown, Steven P

2012-02-01

This article reviews the large increase in applications of high-resolution (1)H magic-angle spinning (MAS) solid-state NMR, in particular two-dimensional heteronuclear and homonuclear (double-quantum and spin-diffusion NOESY-like exchange) experiments, in the last five years. These applications benefit from faster MAS frequencies (up to 80 kHz), higher magnetic fields (up to 1 GHz) and pulse sequence developments (e.g., homonuclear decoupling sequences applicable under moderate and fast MAS). (1)H solid-state NMR techniques are shown to provide unique structural insight for a diverse range of systems including pharmaceuticals, self-assembled supramolecular structures and silica-based inorganic-organic materials, such as microporous and mesoporous materials and heterogeneous organometallic catalysts, for which single-crystal diffraction structures cannot be obtained. The power of NMR crystallography approaches that combine experiment with first-principles calculations of NMR parameters (notably using the GIPAW approach) are demonstrated, e.g., to yield quantitative insight into hydrogen-bonding and aromatic CH-π interactions, as well as to generate trial three-dimensional packing arrangements. It is shown how temperature-dependent changes in the (1)H chemical shift, linewidth and DQ-filtered signal intensity can be analysed to determine the thermodynamics and kinetics of molecular level processes, such as the making and breaking of hydrogen bonds, with particular application to proton-conducting materials. Other applications to polymers and biopolymers, inorganic compounds and bioinorganic systems, paramagnetic compounds and proteins are presented. The potential of new technological advances such as DNP methods and new microcoil designs is described. Copyright © 2011 Elsevier Inc. All rights reserved.

A Model Study to Unravel the Complexity of Bio-Oil from Organic Wastes.

PubMed

Croce, Annamaria; Battistel, Ezio; Chiaberge, Stefano; Spera, Silvia; De Angelis, Francesco; Reale, Samantha

2017-01-10

Binary and ternary mixtures of cellulose, bovine serum albumin (BSA) and tripalmitin, as biomass reference compounds for carbohydrates, proteins and triglycerides, respectively, were treated under hydrothermal liquefaction (HTL) conditions to describe the main reaction pathways involved in the process of bio-oil production from municipal organic wastes. Several analytical techniques (elemental analysis, GC-MS, atmospheric-pressure photo-ionisation high-resolution Fourier transform ion cyclotron resonance mass spectrometry, and 13 C cross-polarisation magic-angle spinning NMR spectroscopy) were used for the molecular-level characterisation of the resulting aqueous phase, solid residue and bio-oil, in particular. The main reaction pathways led to free fatty acids, fatty acid amides, 2,5-diketopiperazines and Maillard-type compounds as the main components of the bio-oil. The relationship of such compounds to the original components of the biomass was thus determined, which highlights the fate of the heteroatom-containing molecules in particular. Finally, the molecular composition of the bio-oils from our reference compounds was matched with that of the bio-oil from municipal organic waste biomass by comparing their high-resolution Fourier transform ion cyclotron resonance mass spectra, and we obtained a surprisingly high similarity. Hence, the ternary mixture acts as a reliable biomass model and is a powerful tool to clarify the degradation mechanisms that occur in the biomass under HTL treatment, with the ultimate goal to improve the HTL process itself by modulating the input of the organic starting matter and then the upgrading steps to bio-fuels. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

On the origin of high ionic conductivity in Na-doped SrSiO 3

DOE PAGES

Chien, Po-Hsiu; Jee, Youngseok; Huang, Chen; ...

2016-02-17

Understanding the local structure and ion dynamics is at the heart of ion conductor research. This paper reports on high-resolution solid-state 29Si, 23Na, and 17O NMR investigation of the structure, chemical composition, and ion dynamics of a newly discovered fast ion conductor, Na-doped SrSiO 3, which exhibited a much higher ionic conductivity than most of current oxide ion conductors. Quantitative analyses reveal that with a small dose (<10 mol%) of Na, the doped Na integrates into the SrSiO 3 structure to form Na xSr 1-xSiO 3-0.5x, and with >10 mol% Na doping, phase separation occurs, leading to the formation ofmore » an amorphous phase β-Na 2Si 2O 5 and a crystalline Sr-rich phase. Variable-temperature 23Na and 17O magic-angle-spinning NMR up to 618 °C have shown significant changes in Na ion dynamics at high temperatures but little oxide ion motion, suggesting that Na ions are responsible for the observed high ionic conductivity. In addition, β-Na 2Si 2O 5 starts to crystallize at temperatures higher than 480 °C with prolonged heating, resulting in reduction in Na+ motion, and thus degradation of ionic conductivity. This study has contributed critical evidence to the understanding of ionic conduction in Na-doped SrSiO 3 and demonstrated that multinuclear high-resolution and high-temperature solid-state NMR is a uniquely useful tool for investigating ion conductors at their operating conditions.« less

Combined Magnetic Resonance Imaging and Spectroscopic Imaging Approach to Molecular Imaging of Prostate Cancer

PubMed Central

Kurhanewicz, John; Swanson, Mark G.; Nelson, Sarah J.; Vigneron, Daniel B.

2005-01-01

Magnetic resonance spectroscopic imaging (MRSI) provides a noninvasive method of detecting small molecular markers (historically the metabolites choline and citrate) within the cytosol and extracellular spaces of the prostate, and is performed in conjunction with high-resolution anatomic imaging. Recent studies in pre-prostatectomy patients have indicated that the metabolic information provided by MRSI combined with the anatomical information provided by MRI can significantly improve the assessment of cancer location and extent within the prostate, extracapsular spread, and cancer aggressiveness. Additionally, pre- and post-therapy studies have demonstrated the potential of MRI/MRSI to provide a direct measure of the presence and spatial extent of prostate cancer after therapy, a measure of the time course of response, and information concerning the mechanism of therapeutic response. In addition to detecting metabolic biomarkers of disease behavior and therapeutic response, MRI/MRSI guidance can improve tissue selection for ex vivo analysis. High-resolution magic angle spinning (1H HR-MAS) spectroscopy provides a full chemical analysis of MRI/MRSI-targeted tissues prior to pathologic and immunohistochemical analyses of the same tissue. Preliminary 1H HR-MAS spectroscopy studies have already identified unique spectral patterns for healthy glandular and stromal tissues and prostate cancer, determined the composition of the composite in vivo choline peak, and identified the polyamine spermine as a new metabolic marker of prostate cancer. The addition of imaging sequences that provide other functional information within the same exam (dynamic contrast uptake imaging and diffusion-weighted imaging) have also demonstrated the potential to further increase the accuracy of prostate cancer detection and characterization. PMID:12353259

Abject Magic: Reasoning Madness in Justine Larbalestier's "Magic or Madness" Trilogy

ERIC Educational Resources Information Center

Potter, Troy

2013-01-01

This paper explores the representation of magic and madness in Justine Larbalestier's "Magic or Madness" trilogy (2005-2007). Throughout the series, magic is constructed as an abject and disabling force that threatens to disable magic-wielders, either through madness or death. Despite being represented as a ubiquitous force, the…

Origins of magic: review of genetic and epigenetic effects.

PubMed

Ramagopalan, Sreeram V; Knight, Marian; Ebers, George C; Knight, Julian C

2007-12-22

To assess the evidence for a genetic basis to magic. Literature review. Harry Potter novels of J K Rowling. Muggles, witches, wizards, and squibs. Limited. Family and twin studies, magical ability, and specific magical skills. Magic shows strong evidence of heritability, with familial aggregation and concordance in twins. Evidence suggests magical ability to be a quantitative trait. Specific magical skills, notably being able to speak to snakes, predict the future, and change hair colour, all seem heritable. A multilocus model with a dominant gene for magic might exist, controlled epistatically by one or more loci, possibly recessive in nature. Magical enhancers regulating gene expressionmay be involved, combined with mutations at specific genes implicated in speech and hair colour such as FOXP2 and MCR1.

The Magic of Balanced Groups: Educational Applications of Magic Squares

ERIC Educational Resources Information Center

Bosse, Michael J.; Nandakumar, N. R.; Ore, Melanie L.

2007-01-01

This paper provides students with many interesting observations regarding the nature of magic squares, magic rectangles, and quasi-magic squares and provides tools for teachers to group students into ability-balanced cooperative learning groups.

Estimating Elevation Angles From SAR Crosstalk

NASA Technical Reports Server (NTRS)

Freeman, Anthony

1994-01-01

Scheme for processing polarimetric synthetic-aperture-radar (SAR) image data yields estimates of elevation angles along radar beam to target resolution cells. By use of estimated elevation angles, measured distances along radar beam to targets (slant ranges), and measured altitude of aircraft carrying SAR equipment, one can estimate height of target terrain in each resolution cell. Monopulselike scheme yields low-resolution topographical data.

Effect of image resolution manipulation in rearfoot angle measurements obtained with photogrammetry

PubMed Central

Sacco, I.C.N.; Picon, A.P.; Ribeiro, A.P.; Sartor, C.D.; Camargo-Junior, F.; Macedo, D.O.; Mori, E.T.T.; Monte, F.; Yamate, G.Y.; Neves, J.G.; Kondo, V.E.; Aliberti, S.

2012-01-01

The aim of this study was to investigate the influence of image resolution manipulation on the photogrammetric measurement of the rearfoot static angle. The study design was that of a reliability study. We evaluated 19 healthy young adults (11 females and 8 males). The photographs were taken at 1536 pixels in the greatest dimension, resized into four different resolutions (1200, 768, 600, 384 pixels) and analyzed by three equally trained examiners on a 96-pixels per inch (ppi) screen. An experienced physiotherapist marked the anatomic landmarks of rearfoot static angles on two occasions within a 1-week interval. Three different examiners had marked angles on digital pictures. The systematic error and the smallest detectable difference were calculated from the angle values between the image resolutions and times of evaluation. Different resolutions were compared by analysis of variance. Inter- and intra-examiner reliability was calculated by intra-class correlation coefficients (ICC). The rearfoot static angles obtained by the examiners in each resolution were not different (P > 0.05); however, the higher the image resolution the better the inter-examiner reliability. The intra-examiner reliability (within a 1-week interval) was considered to be unacceptable for all image resolutions (ICC range: 0.08-0.52). The whole body image of an adult with a minimum size of 768 pixels analyzed on a 96-ppi screen can provide very good inter-examiner reliability for photogrammetric measurements of rearfoot static angles (ICC range: 0.85-0.92), although the intra-examiner reliability within each resolution was not acceptable. Therefore, this method is not a proper tool for follow-up evaluations of patients within a therapeutic protocol. PMID:22911379

Effect of image resolution manipulation in rearfoot angle measurements obtained with photogrammetry.

PubMed

Sacco, I C N; Picon, A P; Ribeiro, A P; Sartor, C D; Camargo-Junior, F; Macedo, D O; Mori, E T T; Monte, F; Yamate, G Y; Neves, J G; Kondo, V E; Aliberti, S

2012-09-01

The aim of this study was to investigate the influence of image resolution manipulation on the photogrammetric measurement of the rearfoot static angle. The study design was that of a reliability study. We evaluated 19 healthy young adults (11 females and 8 males). The photographs were taken at 1536 pixels in the greatest dimension, resized into four different resolutions (1200, 768, 600, 384 pixels) and analyzed by three equally trained examiners on a 96-pixels per inch (ppi) screen. An experienced physiotherapist marked the anatomic landmarks of rearfoot static angles on two occasions within a 1-week interval. Three different examiners had marked angles on digital pictures. The systematic error and the smallest detectable difference were calculated from the angle values between the image resolutions and times of evaluation. Different resolutions were compared by analysis of variance. Inter- and intra-examiner reliability was calculated by intra-class correlation coefficients (ICC). The rearfoot static angles obtained by the examiners in each resolution were not different (P > 0.05); however, the higher the image resolution the better the inter-examiner reliability. The intra-examiner reliability (within a 1-week interval) was considered to be unacceptable for all image resolutions (ICC range: 0.08-0.52). The whole body image of an adult with a minimum size of 768 pixels analyzed on a 96-ppi screen can provide very good inter-examiner reliability for photogrammetric measurements of rearfoot static angles (ICC range: 0.85-0.92), although the intra-examiner reliability within each resolution was not acceptable. Therefore, this method is not a proper tool for follow-up evaluations of patients within a therapeutic protocol.

1H-MRSI pattern perturbation in a mouse glioma: the effects of acute hyperglycemia and moderate hypothermia.

PubMed

Simões, R V; Delgado-Goñi, T; Lope-Piedrafita, S; Arús, C

2010-01-01

MR spectroscopic Imaging (MRSI), with PRESS localization, is used here to monitor the effects of acute hyperglycemia in the spectral pattern of 11 mice bearing GL261 gliomas at normothermia (36.5-37.5 degrees C) and at hypothermia (28.5-29.5 degrees C). These in vivo studies were complemented by ex vivo high resolution magic angle spinning (HR-MAS) analysis of GL261 tumor samples from 6 animals sacrificed by focused microwave irradiation, and blood glucose measurements in 12 control mice. Apparent glucose levels, monitored by in vivo MRSI in brain tumors during acute hyperglycemia, rose to an average of 1.6-fold during hypothermia (p < 0.05), while no significant changes were detected at normothermia, or in control experiments performed at euglycemia, or in normal/peritumoral brain regions. Ex vivo analysis of glioma-bearing mouse brains at hypothermia revealed higher glucose increases in distinct regions during the acute hyperglycemic challenge (up to 6.6-fold at the tumor center), in agreement with maximal in vivo blood glucose changes (5-fold). Phantom studies on taurine plus glucose containing solutions explained the differences between in vivo and ex vivo measurements. Our results also indicate brain tumor heterogeneity in the four animal tumors investigated in response to a defined metabolic challenge.

Metabolite profiling in retinoblastoma identifies novel clinicopathological subgroups

PubMed Central

Kohe, Sarah; Brundler, Marie-Anne; Jenkinson, Helen; Parulekar, Manoj; Wilson, Martin; Peet, Andrew C; McConville, Carmel M

2015-01-01

Background: Tumour classification, based on histopathology or molecular pathology, is of value to predict tumour behaviour and to select appropriate treatment. In retinoblastoma, pathology information is not available at diagnosis and only exists for enucleated tumours. Alternative methods of tumour classification, using noninvasive techniques such as magnetic resonance spectroscopy, are urgently required to guide treatment decisions at the time of diagnosis. Methods: High-resolution magic-angle spinning magnetic resonance spectroscopy (HR-MAS MRS) was undertaken on enucleated retinoblastomas. Principal component analysis and cluster analysis of the HR-MAS MRS data was used to identify tumour subgroups. Individual metabolite concentrations were determined and were correlated with histopathological risk factors for each group. Results: Multivariate analysis identified three metabolic subgroups of retinoblastoma, with the most discriminatory metabolites being taurine, hypotaurine, total-choline and creatine. Metabolite concentrations correlated with specific histopathological features: taurine was correlated with differentiation, total-choline and phosphocholine with retrolaminar optic nerve invasion, and total lipids with necrosis. Conclusions: We have demonstrated that a metabolite-based classification of retinoblastoma can be obtained using ex vivo magnetic resonance spectroscopy, and that the subgroups identified correlate with histopathological features. This result justifies future studies to validate the clinical relevance of these subgroups and highlights the potential of in vivo MRS as a noninvasive diagnostic tool for retinoblastoma patient stratification. PMID:26348444

Quantitative HRMAS proton total correlation spectroscopy applied to cultured melanoma cells treated by chloroethyl nitrosourea: demonstration of phospholipid metabolism alterations.

PubMed

Morvan, Daniel; Demidem, Aicha; Papon, Janine; Madelmont, Jean Claude

2003-02-01

Recent NMR spectroscopy developments, such as high-resolution magic angle spinning (HRMAS) probes and correlation-enhanced 2D sequences, now allow improved investigations of phospholipid (Plp) metabolism. Using these modalities we previously demonstrated that a mouse-bearing melanoma tumor responded to chloroethyl nitrosourea (CENU) treatment in vivo by altering its Plp metabolism. The aims of the present study were to investigate whether HRMAS proton total correlation spectroscopy (TOCSY) could be used as a quantitative technique to probe Plp metabolism, and to determine the Plp metabolism response of cultured B16 melanoma cells to CENU treatment in vitro. The exploited TOCSY signals of Plp derivatives arose from scalar coupling among the protons of neighbor methylene groups within base headgroups (choline and ethanolamine). For strongly expressed Plp derivatives, TOCSY signals were compared to saturation recovery signals and demonstrated a linear relationship. HRMAS proton TOCSY was thus used to provide concentrations of Plp derivatives during long-term follow-up of CENU-treated cell cultures. Strong Plp metabolism alteration was observed in treated cultured cells in vitro involving a down-regulation of phosphocholine, and a dramatic and irreversible increase of phosphoethanolamine. These findings are discussed in relation to previous in vivo data, and to Plp metabolism enzymatic involvement. Copyright 2003 Wiley-Liss, Inc.

Metabolic Profiling of IDH Mutation and Malignant Progression in Infiltrating Glioma

NASA Astrophysics Data System (ADS)

Jalbert, Llewellyn E.; Elkhaled, Adam; Phillips, Joanna J.; Neill, Evan; Williams, Aurelia; Crane, Jason C.; Olson, Marram P.; Molinaro, Annette M.; Berger, Mitchel S.; Kurhanewicz, John; Ronen, Sabrina M.; Chang, Susan M.; Nelson, Sarah J.

2017-03-01

Infiltrating low grade gliomas (LGGs) are heterogeneous in their behavior and the strategies used for clinical management are highly variable. A key factor in clinical decision-making is that patients with mutations in the isocitrate dehydrogenase 1 and 2 (IDH1/2) oncogenes are more likely to have a favorable outcome and be sensitive to treatment. Because of their relatively long overall median survival, more aggressive treatments are typically reserved for patients that have undergone malignant progression (MP) to an anaplastic glioma or secondary glioblastoma (GBM). In the current study, ex vivo metabolic profiles of image-guided tissue samples obtained from patients with newly diagnosed and recurrent LGG were investigated using proton high-resolution magic angle spinning spectroscopy (1H HR-MAS). Distinct spectral profiles were observed for lesions with IDH-mutated genotypes, between astrocytoma and oligodendroglioma histologies, as well as for tumors that had undergone MP. Levels of 2-hydroxyglutarate (2HG) were correlated with increased mitotic activity, axonal disruption, vascular neoplasia, and with several brain metabolites including the choline species, glutamate, glutathione, and GABA. The information obtained in this study may be used to develop strategies for in vivo characterization of infiltrative glioma, in order to improve disease stratification and to assist in monitoring response to therapy.

Hypothalamic metabolic compartmentation during appetite regulation as revealed by magnetic resonance imaging and spectroscopy methods

PubMed Central

Lizarbe, Blanca; Benitez, Ania; Peláez Brioso, Gerardo A.; Sánchez-Montañés, Manuel; López-Larrubia, Pilar; Ballesteros, Paloma; Cerdán, Sebastián

2013-01-01

We review the role of neuroglial compartmentation and transcellular neurotransmitter cycling during hypothalamic appetite regulation as detected by Magnetic Resonance Imaging (MRI) and Spectroscopy (MRS) methods. We address first the neurochemical basis of neuroendocrine regulation in the hypothalamus and the orexigenic and anorexigenic feed-back loops that control appetite. Then we examine the main MRI and MRS strategies that have been used to investigate appetite regulation. Manganese-enhanced magnetic resonance imaging (MEMRI), Blood oxygenation level-dependent contrast (BOLD), and Diffusion-weighted magnetic resonance imaging (DWI) have revealed Mn2+ accumulations, augmented oxygen consumptions, and astrocytic swelling in the hypothalamus under fasting conditions, respectively. High field 1H magnetic resonance in vivo, showed increased hypothalamic myo-inositol concentrations as compared to other cerebral structures. 1H and 13C high resolution magic angle spinning (HRMAS) revealed increased neuroglial oxidative and glycolytic metabolism, as well as increased hypothalamic glutamatergic and GABAergic neurotransmissions under orexigenic stimulation. We propose here an integrative interpretation of all these findings suggesting that the neuroendocrine regulation of appetite is supported by important ionic and metabolic transcellular fluxes which begin at the tripartite orexigenic clefts and become extended spatially in the hypothalamus through astrocytic networks becoming eventually MRI and MRS detectable. PMID:23781199

Combined transcriptome and metabolome analyses of metformin effects reveal novel links between metabolic networks in steroidogenic systems.

PubMed

Udhane, Sameer S; Legeza, Balazs; Marti, Nesa; Hertig, Damian; Diserens, Gaëlle; Nuoffer, Jean-Marc; Vermathen, Peter; Flück, Christa E

2017-08-17

Metformin is an antidiabetic drug, which inhibits mitochondrial respiratory-chain-complex I and thereby seems to affect the cellular metabolism in many ways. It is also used for the treatment of the polycystic ovary syndrome (PCOS), the most common endocrine disorder in women. In addition, metformin possesses antineoplastic properties. Although metformin promotes insulin-sensitivity and ameliorates reproductive abnormalities in PCOS, its exact mechanisms of action remain elusive. Therefore, we studied the transcriptome and the metabolome of metformin in human adrenal H295R cells. Microarray analysis revealed changes in 693 genes after metformin treatment. Using high resolution magic angle spinning nuclear magnetic resonance spectroscopy (HR-MAS-NMR), we determined 38 intracellular metabolites. With bioinformatic tools we created an integrated pathway analysis to understand different intracellular processes targeted by metformin. Combined metabolomics and transcriptomics data analysis showed that metformin affects a broad range of cellular processes centered on the mitochondrium. Data confirmed several known effects of metformin on glucose and androgen metabolism, which had been identified in clinical and basic studies previously. But more importantly, novel links between the energy metabolism, sex steroid biosynthesis, the cell cycle and the immune system were identified. These omics studies shed light on a complex interplay between metabolic pathways in steroidogenic systems.

Testicular lactate content is compromised in men with Klinefelter Syndrome.

PubMed

Alves, Marco G; Martins, Ana D; Jarak, Ivana; Barros, Alberto; Silva, Joaquina; Sousa, Mário; Oliveira, Pedro F

2016-03-01

Klinefelter syndrome (KS) is the most common genetic cause of human infertility, but the mechanism(s) responsible for its phenotype remain largely unknown. KS is associated with alterations in body composition and with a higher risk of developing metabolic diseases. We therefore hypothesized that KS men seeking fertility treatment possess an altered testicular metabolism profile that may hamper the nutritional support of spermatogenesis. Testicular biopsies from control (46, XY) (n = 6) and KS (47, XXY) (n = 6) individuals were collected and analyzed by proton high-resolution magic-angle spinning nuclear magnetic resonance spectroscopy. The mRNA and protein expression of crucial glycolysis-associated enzymes and transporters were evaluated in parallel by quantitative PCR and Western blot, respectively. Our data revealed altered regulation of glucose transporters (GLUT1 and GLUT3); phosphofructokinase 1, liver isoform (PFKL); and lactate dehydrogenase A (LDHA) expression in the testis of KS patients. Moreover, we detected a severe reduction in lactate and creatine accumulation within testicular tissue from KS men. The aberrant levels of the biomarkers detected in testicular biopsies of KS men may therefore be associated with the infertility phenotypes presented by these men. Mol. Reprod. Dev. 83: 208-216, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Expertise among professional magicians: an interview study.

PubMed

Rissanen, Olli; Pitkänen, Petteri; Juvonen, Antti; Kuhn, Gustav; Hakkarainen, Kai

2014-01-01

The purpose of the present investigation was to analyse interviews of highly regarded Finnish magicians. Social network analysis (N = 120) was used to identify Finland's most highly regarded magicians (N = 16). The selected participants' careers in professional magic and various aspects of their professional conduct were examined by relying on semi-structured interviews. The results revealed that cultivation of professional level competence in magic usually requires an extensive period of time compared with other domains of expertise. Magic is a unique performing art and it differs from other professions focusing on deceiving the audience. A distinctive feature of magical expertise is that the process takes place entirely through informal training supported by communities of magical practitioners. Three interrelated aspects of magical activity were distinguished: magic tricks, performance, and audience. Although magic tricks constitute a central aspect of magic activity, the participants did not talk about their tricks extensively; this is in accordance with the secretive nature of magic culture. The interviews revealed that a core aspect of the magicians' activity is performance in front of an audience that repeatedly validates competence cultivated through years of practice. The interviewees reported investing a great deal of effort in planning, orchestrating, and reflecting on their performances. Close interaction with the audience plays an important role in most interviewees' activity. Many participants put a great deal of effort in developing novel magic tricks. It is common to borrow magic effects from fellow magicians and develop novel methods of implementation. Because magic tricks or programs are not copyrighted, many interviewees considered "stealing" an unacceptable and unethical aspect of magical activity. The interviewees highlighted the importance of personality and charisma in the successful pursuit of magic activity.

Expertise among professional magicians: an interview study

PubMed Central

Rissanen, Olli; Pitkänen, Petteri; Juvonen, Antti; Kuhn, Gustav; Hakkarainen, Kai

2014-01-01

The purpose of the present investigation was to analyse interviews of highly regarded Finnish magicians. Social network analysis (N = 120) was used to identify Finland's most highly regarded magicians (N = 16). The selected participants' careers in professional magic and various aspects of their professional conduct were examined by relying on semi-structured interviews. The results revealed that cultivation of professional level competence in magic usually requires an extensive period of time compared with other domains of expertise. Magic is a unique performing art and it differs from other professions focusing on deceiving the audience. A distinctive feature of magical expertise is that the process takes place entirely through informal training supported by communities of magical practitioners. Three interrelated aspects of magical activity were distinguished: magic tricks, performance, and audience. Although magic tricks constitute a central aspect of magic activity, the participants did not talk about their tricks extensively; this is in accordance with the secretive nature of magic culture. The interviews revealed that a core aspect of the magicians' activity is performance in front of an audience that repeatedly validates competence cultivated through years of practice. The interviewees reported investing a great deal of effort in planning, orchestrating, and reflecting on their performances. Close interaction with the audience plays an important role in most interviewees' activity. Many participants put a great deal of effort in developing novel magic tricks. It is common to borrow magic effects from fellow magicians and develop novel methods of implementation. Because magic tricks or programs are not copyrighted, many interviewees considered “stealing” an unacceptable and unethical aspect of magical activity. The interviewees highlighted the importance of personality and charisma in the successful pursuit of magic activity. PMID:25566156

Probing membrane protein structure using water polarization transfer solid-state NMR.

PubMed

Williams, Jonathan K; Hong, Mei

2014-10-01

Water plays an essential role in the structure and function of proteins, lipid membranes and other biological macromolecules. Solid-state NMR heteronuclear-detected (1)H polarization transfer from water to biomolecules is a versatile approach for studying water-protein, water-membrane, and water-carbohydrate interactions in biology. We review radiofrequency pulse sequences for measuring water polarization transfer to biomolecules, the mechanisms of polarization transfer, and the application of this method to various biological systems. Three polarization transfer mechanisms, chemical exchange, spin diffusion and NOE, manifest themselves at different temperatures, magic-angle-spinning frequencies, and pulse irradiations. Chemical exchange is ubiquitous in all systems examined so far, and spin diffusion plays the key role in polarization transfer within the macromolecule. Tightly bound water molecules with long residence times are rare in proteins at ambient temperature. The water polarization-transfer technique has been used to study the hydration of microcrystalline proteins, lipid membranes, and plant cell wall polysaccharides, and to derive atomic-resolution details of the kinetics and mechanism of ion conduction in channels and pumps. Using this approach, we have measured the water polarization transfer to the transmembrane domain of the influenza M2 protein to obtain information on the structure of this tetrameric proton channel. At short mixing times, the polarization transfer rates are site-specific and depend on the pH, labile protons, sidechain conformation, as well as the radial position of the residues in this four-helix bundle. Despite the multiple dependences, the initial transfer rates reflect the periodic nature of the residue positions from the water-filled pore, thus this technique provides a way of gleaning secondary structure information, helix tilt angle, and the oligomeric structure of membrane proteins. Copyright © 2014 Elsevier Inc. All rights reserved.

Multiple-quantum spin counting in magic-angle-spinning NMR via low-power symmetry-based dipolar recoupling

NASA Astrophysics Data System (ADS)

Teymoori, Gholamhasan; Pahari, Bholanath; Viswanathan, Elumalai; Edén, Mattias

2013-11-01

By using a symmetry-based R281R28-1 double-quantum (2Q) dipolar recoupling sequence, we demonstrate high-order multiple-quantum coherence (MQC) excitation at fast magic-angle spinning (MAS) frequencies up to 34 kHz. This scheme combines several attractive features, such as a relatively high dipolar scaling factor, good compensation to rf-errors, isotropic and anisotropic chemical shifts, as well as an ultra-low radio-frequency (rf) power requirement. The latter translates into nutation frequencies below 30 kHz for MAS rates up to 60 kHz, thereby permitting rf application for very long excitation periods without risk of damaging the NMR probehead or sample, while the compensation to chemical shifts improves as the MAS rate increases. 31P MQC spin counting is demonstrated on powders of calcium hydroxyapatite (Ca5(PO4)3OH) and anhydrous sodium diphosphate (Na4P2O7), from which all even coherence orders up to 30 and 14 were detected, respectively, over the respective MAS ranges of 15-24 kHz and 20-34 kHz. The amplitude distributions among the 31P MQC orders depend on the precise nutation frequency during recoupling, despite that the highest detected order was relatively insensitive to this parameter. An observed gradual transition from a Gaussian to exponential functionality of the MQC amplitude-profile is discussed in relation to the prevailing approach to derive spin-cluster sizes by fitting the MQC amplitude-distribution to a Gaussian decay, where minor systematic deviations between the model and experimental data are frequently reported.

Radiofrequency fields in MAS solid state NMR probes.

PubMed

Tošner, Zdeněk; Purea, Armin; Struppe, Jochem O; Wegner, Sebastian; Engelke, Frank; Glaser, Steffen J; Reif, Bernd

2017-11-01

We present a detailed analysis of the radiofrequency (RF) field over full volume of a rotor that is generated in a solenoid coil. On top of the usually considered static distribution of amplitudes along the coil axis we describe dynamic radial RF inhomogeneities induced by sample rotation. During magic angle spinning (MAS), the mechanical rotation of the sample about the magic angle, a spin packet travels through areas of different RF fields and experiences periodical modulations of both the RF amplitude and the phase. These modulations become particularly severe at the end regions of the coil where the relative RF amplitude varies up to ±25% and the RF phase changes within ±30°. Using extensive numerical simulations we demonstrate effects of RF inhomogeneity on pulse calibration and for the ramped CP experiment performed at a wide range of MAS rates. In addition, we review various methods to map RF fields using a B 0 gradient along the sample (rotor axis) for imaging purposes. Under such a gradient, a nutation experiment provides directly the RF amplitude distribution, a cross polarization experiment images the correlation of the RF fields on the two channels according to the Hartmann-Hahn matching condition, while a spin-lock experiment allows to calibrate the RF amplitude employing the rotary resonance recoupling condition. Knowledge of the RF field distribution in a coil provides key to understand its effects on performance of a pulse sequence at the spectrometer and enables to set robustness requirements in the experimental design. Copyright © 2017 Elsevier Inc. All rights reserved.

Electron paramagnetic resonance, scanning electron microscopy with energy dispersion X-ray spectrometry, X-ray powder diffraction, and NMR characterization of iron-rich fired clays.

PubMed

Presciutti, Federica; Capitani, Donatella; Sgamellotti, Antonio; Brunetti, Brunetto Giovanni; Costantino, Ferdinando; Viel, Stéphane; Segre, Annalaura

2005-12-01

The aim of this study is to clarify the structure of an iron-rich clay and the structural changes involved in the firing process as a preliminary step to get information on ancient ceramic technology. To this purpose, illite-rich clay samples fired at different temperatures were characterized using a multitechnique approach, i.e., by electron paramagnetic resonance, scanning electron microscopy with electron dispersion X-ray spectrometry, X-ray powder diffraction, magic angle spinning and multiple quantum magic angle spinning NMR. During firing, four main reaction processes occur: dehydration, dehydroxylation, structural breakdown, and recrystallization. When the results are combined from all characterization methods, the following conclusions could be obtained. Interlayer H2O is located close to aluminum in octahedral sites and is driven off at temperatures lower than 600 degrees C. Between 600 and 700 degrees C dehydroxylation occurs whereas, between 800 and 900 degrees C, the aluminum in octahedral sites disappears, due to the breakdown of the illite structure, and all iron present is oxidized to Fe3+. In samples fired at 1000 and 1100 degrees C iron clustering was observed as well as large single crystals of iron with the occurrence of ferro- or ferrimagnetic effects. Below 900 degrees C the aluminum in octahedral sites presents a continuous distribution of chemical shift, suggesting the presence of slightly distorted sites. Finally, over the whole temperature range, the presence of at least two tetrahedral aluminum sites was revealed, characterized by different values of the quadrupolar coupling constant.

MAGIC database and interfaces: an integrated package for gene discovery and expression.

PubMed

Cordonnier-Pratt, Marie-Michèle; Liang, Chun; Wang, Haiming; Kolychev, Dmitri S; Sun, Feng; Freeman, Robert; Sullivan, Robert; Pratt, Lee H

2004-01-01

The rapidly increasing rate at which biological data is being produced requires a corresponding growth in relational databases and associated tools that can help laboratories contend with that data. With this need in mind, we describe here a Modular Approach to a Genomic, Integrated and Comprehensive (MAGIC) Database. This Oracle 9i database derives from an initial focus in our laboratory on gene discovery via production and analysis of expressed sequence tags (ESTs), and subsequently on gene expression as assessed by both EST clustering and microarrays. The MAGIC Gene Discovery portion of the database focuses on information derived from DNA sequences and on its biological relevance. In addition to MAGIC SEQ-LIMS, which is designed to support activities in the laboratory, it contains several additional subschemas. The latter include MAGIC Admin for database administration, MAGIC Sequence for sequence processing as well as sequence and clone attributes, MAGIC Cluster for the results of EST clustering, MAGIC Polymorphism in support of microsatellite and single-nucleotide-polymorphism discovery, and MAGIC Annotation for electronic annotation by BLAST and BLAT. The MAGIC Microarray portion is a MIAME-compliant database with two components at present. These are MAGIC Array-LIMS, which makes possible remote entry of all information into the database, and MAGIC Array Analysis, which provides data mining and visualization. Because all aspects of interaction with the MAGIC Database are via a web browser, it is ideally suited not only for individual research laboratories but also for core facilities that serve clients at any distance.

Development of a high resolution optical-fiber tilt sensor by F-P filter

NASA Astrophysics Data System (ADS)

Pan, Jianjun; Nan, Qiuming; Li, Shujie; Hao, Zhonghua

2017-04-01

A high-resolution tilt sensor is developed, which is composed of a pair of optical fiber collimators and a simple pendulum with an F-P filter. The tilt angle is measured by demodulating the shift of center wavelength of F-P filter, which is caused by incidence angle changing. The relationship between tilted angle and the center wavelength is deduced. Calibration experiment results also confirm the deduction, and show that it is easy to obtain a high resolution. Setting the initial angle to 6degree, the measurement range is ±3degree, its average sensitivity is 1104pm/degree, and its average resolution is as high as 0.0009degree.

Increased horizontal viewing zone angle of a hologram by resolution redistribution of a spatial light modulator.

PubMed

Takaki, Yasuhiro; Hayashi, Yuki

2008-07-01

The narrow viewing zone angle is one of the problems associated with electronic holography. We propose a technique that enables the ratio of horizontal and vertical resolutions of a spatial light modulator (SLM) to be altered. This technique increases the horizontal resolution of a SLM several times, so that the horizontal viewing zone angle is also increased several times. A SLM illuminated by a slanted point light source array is imaged by a 4f imaging system in which a horizontal slit is located on the Fourier plane. We show that the horizontal resolution was increased four times and that the horizontal viewing zone angle was increased approximately four times.

Application of a Resource Theory for Magic States to Fault-Tolerant Quantum Computing.

PubMed

Howard, Mark; Campbell, Earl

2017-03-03

Motivated by their necessity for most fault-tolerant quantum computation schemes, we formulate a resource theory for magic states. First, we show that robustness of magic is a well-behaved magic monotone that operationally quantifies the classical simulation overhead for a Gottesman-Knill-type scheme using ancillary magic states. Our framework subsequently finds immediate application in the task of synthesizing non-Clifford gates using magic states. When magic states are interspersed with Clifford gates, Pauli measurements, and stabilizer ancillas-the most general synthesis scenario-then the class of synthesizable unitaries is hard to characterize. Our techniques can place nontrivial lower bounds on the number of magic states required for implementing a given target unitary. Guided by these results, we have found new and optimal examples of such synthesis.

Magic star puzzle for educational mathematics

NASA Astrophysics Data System (ADS)

Gan, Yee Siang; Fong, Wan Heng; Sarmin, Nor Haniza

2013-04-01

One of the interesting fields in recreational mathematics is the magic number arrangement. There are different kinds of arrays in the arrangement for a group of numbers. In particular, one of the arrays in magic number arrangement is called magic star. In fact, magic star involves combinatorics that contributes to geometrical analysis and number theory. Hence, magic star is suitable to be introduced as educational mathematics to cultivate interest in different area of mathematics. To obtain the solutions of normal magic stars of order six, the possible sets of numbers for every line in a magic star have been considered. Previously, the calculation for obtaining the solutions has been done manually which is time-consuming. Therefore, a programming code to generate all the fundamental solutions for normal magic star of order six without including the properties of rotation and reflection has been done. In this puzzle, a magic star puzzle is created by using Matlab software, which enables a user to verify the entries for the cells of magic star of order six. Moreover, it is also user-friendly as it provides interactive commands on the inputs given by the user, which enables the user to detect the incorrect inputs. In addition, user can also choose to view all the fundamental solutions as generated by the programming code.

77 FR 58416 - Large Scale Networking (LSN); Middleware and Grid Interagency Coordination (MAGIC) Team

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-20

... Coordination (MAGIC) Team AGENCY: The Networking and Information Technology Research and Development (NITRD.... Dates/Location: The MAGIC Team meetings are held on the first Wednesday of each month, 2:00-4:00pm, at... participation is available for each meeting. Please reference the MAGIC Team Web site for updates. Magic Web...

78 FR 70076 - Large Scale Networking (LSN)-Middleware and Grid Interagency Coordination (MAGIC) Team

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-22

... Coordination (MAGIC) Team AGENCY: The Networking and Information Technology Research and Development (NITRD... MAGIC Team meetings are held on the first Wednesday of each month, 2:00-4:00 p.m., at the National... for each meeting. Please reference the MAGIC Team Web site for updates. Magic Web site: The agendas...

Emotional salience, emotional awareness, peculiar beliefs, and magical thinking.

PubMed

Berenbaum, Howard; Boden, M Tyler; Baker, John P

2009-04-01

Two studies with college student participants (Ns = 271 and 185) tested whether peculiar beliefs and magical thinking were associated with (a) the emotional salience of the stimuli about which individuals may have peculiar beliefs or magical thinking, (b) attention to emotion, and (c) clarity of emotion. Study 1 examined belief that a baseball team was cursed. Study 2 measured magical thinking using a procedure developed by P. Rozin and C. Nemeroff (2002). In both studies, peculiar beliefs and magical thinking were associated with Salience x Attention x Clarity interactions. Among individuals for whom the objects of the belief-magical thinking were highly emotionally salient and who had high levels of attention to emotion, higher levels of emotional clarity were associated with increased peculiar beliefs-magical thinking. In contrast, among individuals for whom the objects of the belief-magical thinking were not emotionally salient and who had high levels of attention to emotion, higher levels of emotional clarity were associated with diminished peculiar beliefs-magical thinking. (c) 2009 APA, all rights reserved.

Note: high precision angle generator using multiple ultrasonic motors and a self-calibratable encoder.

PubMed

Kim, Jong-Ahn; Kim, Jae Wan; Kang, Chu-Shik; Jin, Jonghan; Eom, Tae Bong

2011-11-01

We present an angle generator with high resolution and accuracy, which uses multiple ultrasonic motors and a self-calibratable encoder. A cylindrical air bearing guides a rotational motion, and the ultrasonic motors achieve high resolution over the full circle range with a simple configuration. The self-calibratable encoder can compensate the scale error of a divided circle (signal period: 20") effectively by applying the equal-division-averaged method. The angle generator configures a position feedback control loop using the readout of the encoder. By combining the ac and dc operation mode, the angle generator produced stepwise angular motion with 0.005" resolution. We also evaluated the performance of the angle generator using a precision angle encoder and an autocollimator. The expanded uncertainty (k = 2) in the angle generation was estimated less than 0.03", which included the calibrated scale error and the nonlinearity error. © 2011 American Institute of Physics

Fast REDOR with CPMG multiple-echo acquisition

NASA Astrophysics Data System (ADS)

Hung, Ivan; Gan, Zhehong

2014-01-01

Rotational-Echo Double Resonance (REDOR) is a widely used experiment for distance measurements in solids. The conventional REDOR experiment measures the signal dephasing from hetero-nuclear recoupling under magic-angle spinning (MAS) in a point by point manner. A modified Carr-Purcell Meiboom-Gill (CPMG) multiple-echo scheme is introduced for fast REDOR measurement. REDOR curves are measured from the CPMG echo amplitude modulation under dipolar recoupling. The real time CPMG-REDOR experiment can speed up the measurement by an order of magnitude. The effects from hetero-nuclear recoupling, the Bloch-Siegert shift and echo truncation to the signal acquisition are discussed and demonstrated.

MAS NMR of HIV-1 protein assemblies

NASA Astrophysics Data System (ADS)

Suiter, Christopher L.; Quinn, Caitlin M.; Lu, Manman; Hou, Guangjin; Zhang, Huilan; Polenova, Tatyana

2015-04-01

The negative global impact of the AIDS pandemic is well known. In this perspective article, the utility of magic angle spinning (MAS) NMR spectroscopy to answer pressing questions related to the structure and dynamics of HIV-1 protein assemblies is examined. In recent years, MAS NMR has undergone major technological developments enabling studies of large viral assemblies. We discuss some of these evolving methods and technologies and provide a perspective on the current state of MAS NMR as applied to the investigations into structure and dynamics of HIV-1 assemblies of CA capsid protein and of Gag maturation intermediates.

[Magical thinking in healthy people and in schizophrenia].

PubMed

Jarosz, M

1996-01-01

Different conditions of magical thinking have been analyzed. A formation of the proportion "realistic thinking - magical thinking" in paranoid schizophrenia has been discussed and the characteristic features of magical thinking in schizophrenia have been indicated.

Acceleration of natural-abundance solid-state MAS NMR measurements on bone by paramagnetic relaxation from gadolinium-DTPA

NASA Astrophysics Data System (ADS)

Mroue, Kamal H.; Zhang, Rongchun; Zhu, Peizhi; McNerny, Erin; Kohn, David H.; Morris, Michael D.; Ramamoorthy, Ayyalusamy

2014-07-01

Reducing the data collection time without affecting the signal intensity and spectral resolution is one of the major challenges for the widespread application of multidimensional nuclear magnetic resonance (NMR) spectroscopy, especially in experiments conducted on complex heterogeneous biological systems such as bone. In most of these experiments, the NMR data collection time is ultimately governed by the proton spin-lattice relaxation times (T1). For over two decades, gadolinium(III)-DTPA (Gd-DTPA, DTPA = Diethylene triamine pentaacetic acid) has been one of the most widely used contrast-enhancement agents in magnetic resonance imaging (MRI). In this study, we demonstrate that Gd-DTPA can also be effectively used to enhance the longitudinal relaxation rates of protons in solid-state NMR experiments conducted on bone without significant line-broadening and chemical-shift-perturbation side effects. Using bovine cortical bone samples incubated in different concentrations of Gd-DTPA complex, the 1H T1 values were calculated from data collected by 1H spin-inversion recovery method detected in natural-abundance 13C cross-polarization magic angle spinning (CPMAS) NMR experiments. Our results reveal that the 1H T1 values can be successfully reduced by a factor of 3.5 using as low as 10 mM Gd-DTPA without reducing the spectral resolution and thus enabling faster data acquisition of the 13C CPMAS spectra. These results obtained from 13C-detected CPMAS experiments were further confirmed using 1H-detected ultrafast MAS experiments on Gd-DTPA doped bone samples. This approach considerably improves the signal-to-noise ratio per unit time of NMR experiments applied to bone samples by reducing the experimental time required to acquire the same number of scans.

Acceleration of natural-abundance solid-state MAS NMR measurements on bone by paramagnetic relaxation from gadolinium-DTPA.

PubMed

Mroue, Kamal H; Zhang, Rongchun; Zhu, Peizhi; McNerny, Erin; Kohn, David H; Morris, Michael D; Ramamoorthy, Ayyalusamy

2014-07-01

Reducing the data collection time without affecting the signal intensity and spectral resolution is one of the major challenges for the widespread application of multidimensional nuclear magnetic resonance (NMR) spectroscopy, especially in experiments conducted on complex heterogeneous biological systems such as bone. In most of these experiments, the NMR data collection time is ultimately governed by the proton spin-lattice relaxation times (T1). For over two decades, gadolinium(III)-DTPA (Gd-DTPA, DTPA=Diethylene triamine pentaacetic acid) has been one of the most widely used contrast-enhancement agents in magnetic resonance imaging (MRI). In this study, we demonstrate that Gd-DTPA can also be effectively used to enhance the longitudinal relaxation rates of protons in solid-state NMR experiments conducted on bone without significant line-broadening and chemical-shift-perturbation side effects. Using bovine cortical bone samples incubated in different concentrations of Gd-DTPA complex, the (1)H T1 values were calculated from data collected by (1)H spin-inversion recovery method detected in natural-abundance (13)C cross-polarization magic angle spinning (CPMAS) NMR experiments. Our results reveal that the (1)H T1 values can be successfully reduced by a factor of 3.5 using as low as 10mM Gd-DTPA without reducing the spectral resolution and thus enabling faster data acquisition of the (13)C CPMAS spectra. These results obtained from (13)C-detected CPMAS experiments were further confirmed using (1)H-detected ultrafast MAS experiments on Gd-DTPA doped bone samples. This approach considerably improves the signal-to-noise ratio per unit time of NMR experiments applied to bone samples by reducing the experimental time required to acquire the same number of scans. Copyright © 2014 Elsevier Inc. All rights reserved.

Studies of Secondary Melanoma on C57BL/6J Mouse Liver Using 1H NMR Metabolomics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng, Ju; Isern, Nancy G.; Burton, Sarah D.

2013-10-31

NMR metabolomics, consisting of solid state high resolution (hr) magic angle spinning (MAS) 1H NMR (1H hr-MAS), liquid state high resolution 1H-NMR, and principal components analysis (PCA) has been used to study secondary metastatic B16-F10 melanoma in C57BL/6J mouse liver . The melanoma group can be differentiated from its control group by PCA analysis of the absolute concentrations or by the absolute peak intensities of metabolites from either 1H hr-MAS NMR data on intact liver tissues or liquid state 1H-NMR spectra on liver tissue extracts. In particular, we found that the absolute concentrations of alanine, glutamate, creatine, creatinine, fumarate andmore » cholesterol are elevated in the melanoma group as compared to controls, while the absolute concentrations of succinate, glycine, glucose, and the family of linear lipids including long chain fatty acids, total choline and acylglycerol are decreased. The ratio of glycerophosphocholine to phosphocholine is increased by about 1.5 fold in the melanoma group, while the absolute concentration of total choline is actually lower in melanoma mice. These results suggest the following picture in secondary melanoma metastasis: Linear lipid levels are decreased by beta oxidation in the melanoma group, which contributes to an increase in the synthesis of cholesterol, and also provides an energy source input for TCA cycle. These findings suggest a link between lipid oxidation, the TCA cycle and the hypoxia-inducible factors (HIF) signal pathway in tumor metastases. Thus this study indicates that the metabolic profile derived from NMR analysis can provide a valuable bio-signature of malignancy and cell hypoxia in metastatic melanoma.« less

Molecular insight into the electrostatic membrane surface potential by 14n/31p MAS NMR spectroscopy: nociceptin-lipid association.

PubMed

Lindström, Fredrick; Williamson, Philip T F; Gröbner, Gerhard

2005-05-11

Exploiting naturally abundant (14)N and (31)P nuclei by high-resolution MAS NMR (magic angle spinning nuclear magnetic resonance) provides a molecular view of the electrostatic potential present at the surface of biological model membranes, the electrostatic charge distribution across the membrane interface, and changes that occur upon peptide association. The spectral resolution in (31)P and (14)N MAS NMR spectra is sufficient to probe directly the negatively charged phosphate and positively charged choline segment of the electrostatic P(-)-O-CH(2)-CH(2)-N(+)(CH(3))(3) headgroup dipole of zwitterionic DMPC (dimyristoylphosphatidylcholine) in mixed-lipid systems. The isotropic shifts report on the size of the potential existing at the phosphate and ammonium group within the lipid headgroup while the chemical shielding anisotropy ((31)P) and anisotropic quadrupolar interaction ((14)N) characterize changes in headgroup orientation in response to surface potential. The (31)P/(14)N isotropic chemical shifts for DMPC show opposing systematic changes in response to changing membrane potential, reflecting the size of the electrostatic potential at opposing ends of the P(-)-N(+) dipole. The orientational response of the DMPC lipid headgroup to electrostatic surface variations is visible in the anisotropic features of (14)N and (31)P NMR spectra. These features are analyzed in terms of a modified "molecular voltmeter" model, with changes in dynamic averaging reflecting the tilt of the C(beta)-N(+)(CH)(3) choline and PO(4)(-) segment. These properties have been exploited to characterize the changes in surface potential upon the binding of nociceptin to negatively charged membranes, a process assumed to proceed its agonistic binding to its opoid G-protein coupled receptor.

Neurochemical Changes after Acute Binge Toluene Inhalation in Adolescent and Adult Rats: A High-Resolution Magnetic Resonance Spectroscopy Study

PubMed Central

O'Leary-Moore, Shonagh K.; Galloway, Matthew P.; McMechan, Andrew P.; Irtenkauf, Susan; Hannigan, John H.; Bowen, Scott E.

2009-01-01

Inhalant abuse in young people is a growing public health concern. We reported previously that acute toluene intoxication in young rats, using a pattern of exposures that approximate abuse patterns of inhalant use in humans, significantly altered neurochemical measures in select brain regions. In this study, adolescent and young adult rats were exposed similarly to an acute (2 × 15 min), high dose (8000 − 12000 ppm) of toluene and high-resolution magic angle spinning proton magnetic resonance spectroscopy (HR-MAS 1H-MRS) was used to assess neurochemical profiles of tissue samples from a number of brain regions collected immediately following solvent exposure. The current investigation focused on N-acetyl-aspartate (NAA), choline-containing compounds, creatine, glutamate, GABA, and glutamine. Contrary to our predictions, no significant alterations were found in levels of NAA, choline, creatine, glutamate, or glutamine in adolescent animals. In contrast to these minimal effects in adolescents, binge toluene exposure altered several neurochemical parameters in young adult rats, including decreased levels of choline and GABA in the frontal cortex and striatum and lowered glutamine and NAA levels in the frontal cortex. One of the more robust findings was a wide-ranging increase in lactate after toluene exposure in adult animals, an effect not observed in adolescents. These age-dependent effects of toluene are distinct from those reported previously in juvenile rats and suggest a developmental difference in vulnerability to the effects of inhalants. Specifically, the results suggest that the neurochemical response to toluene in adolescents is attenuated compared to adults, and imply an association between these neurochemical differences and age-influenced differences in solvent abuse in humans. PMID:19628036

Development of DNP-Enhanced High-Resolution Solid-State NMR System for the Characterization of the Surface Structure of Polymer Materials

NASA Astrophysics Data System (ADS)

Horii, Fumitaka; Idehara, Toshitaka; Fujii, Yutaka; Ogawa, Isamu; Horii, Akifumi; Entzminger, George; Doty, F. David

2012-07-01

A dynamic nuclear polarization (DNP)-enhanced cross-polarization/magic-angle spinning (DNP/CP/MAS) NMR system has been developed by combining a 200 MHz Chemagnetics CMX-200 spectrometer operating at 4.7 T with a high-power 131.5 GHz Gyrotron FU CW IV. The 30 W sub-THz wave generated in a long pulse TE _{{41}}^{{(1)}} mode with a frequency of 5 Hz was successfully transmitted to the modified Doty Scientific low-temperature CP/MAS probe through copper smooth-wall circular waveguides. Since serious RF noises on NMR signals by arcing in the electric circuit of the probe and undesired sample heating were induced by the continuous sub-THz wave pulse irradiation with higher powers, the on-off sub-THz wave pulse irradiation synchronized with the NMR detection was developed and the appropriate setting of the irradiation time and the cooling time corresponding to the non-irradiation time was found to be very effective for the suppression of the arcing and the sample heating. The attainable maximum DNP enhancement was more than 30 folds for C1 13 C-enriched D-glucose dissolved in the frozen medium containing mono-radical 4-amino-TEMPO. The first DNP/CP/MAS 13 C NMR spectra of poly(methyl methacrylate) (PMMA) sub-micron particles were obtained at the dispersed state in the same frozen medium, indicating that DNP-enhanced 1H spins effectively diffuse from the medium to the PMMA particles through their surface and are detected as high-resolution 13 C spectra in the surficial region to which the 1H spins reach. On the basis of these results, the possibility of the DNP/CP/MAS NMR characterization of the surface structure of nanomaterials including polymer materials was discussed.

Magic 2010 RASR Team

DTIC Science & Technology

2010-12-15

MAGIC 2010 – FINAL REPORT RASR TEAM - CONTRACT NO: FA2386-10-1-4021 December 15, 2010 Final Report for AOARD Grant FA23861014021 – MAGIC ... MAGIC 2010 Competition - Robotic Research Team (RASR) Abstract: The RASR team developed a system for the coordination of groups of unmanned...accomplish those missions. Our team goal was to develop a system that can provide long term value to the war-fighter, utilizing MAGIC 2010 as a stepping

Characterization of molecular disorder in vapor-deposited thin films of aluminum tris(quinoline-8-olate) by one-dimensional 27Al NMR under magic angle spinning.

PubMed

Utz, Marcel; Nandagopal, Magesh; Mathai, Mathew; Papadimitrakopoulos, Fotios

2006-01-21

Aluminum tris (quinoline-8-olate) (Alq3) is used as an electron-transport layer in organic light-emitting diodes. The material can be obtained in a wide range of different solid phases, both crystalline and amorphous, by deposition from the vapor phase or from solution under controlled conditions. While the structure of the crystalline polymorphs of Alq3 has been investigated thoroughly by x-ray diffraction as well as solid-state NMR, very little information is currently available on the amount of structural disorder in the amorphous forms of Alq3. In the present contribution, we report the use of 27Al NMR spectroscopy in the solid state under magic angle spinning to extract such information from amorphous vapor deposits of Alq3. The NMR spectra obtained from these samples exhibit different degrees of broadening, reflecting distributions of the electric-field gradient tensor at the site of the aluminum ion. These distributions can be obtained from the NMR spectra by solving the corresponding inverse problem. From these results, the magnitude of structural disorder in terms of molecular geometry has been estimated by density-functional theory calculations. It was found that the electric-field gradient anisotropy delta follows a bimodal distribution. Its majority component is centered around delta values comparable to the meridianal alpha crystal polymorph and has a width of about 10%, corresponding to distortions of the molecular geometry of a few degrees in the orientation of the ligands. Alq3 samples obtained at higher deposition rates exhibit higher degrees of disorder. The minor component, present at about 7%, has a much smaller anisotropy, suggesting that it may be due to the facial isomer of Alq3.

Fast Magic-Angle Spinning Three-Dimensional NMR Experiment for Simultaneously Probing H-H and N-H Proximities in Solids.

PubMed

Reddy, G N Manjunatha; Malon, Michal; Marsh, Andrew; Nishiyama, Yusuke; Brown, Steven P

2016-12-06

A fast magic-angle spinning (MAS, 70 kHz) solid-state NMR experiment is presented that combines 1 H Double-Quantum (DQ) and 14 N- 1 H HMQC (Heteronuclear Multiple-Quantum Coherence) pulse-sequence elements, so as to simultaneously probe H-H and N-H proximities in molecular solids. The proposed experiment can be employed in both two-dimensional (2D) and three-dimensional (3D) versions: first, a 2D 14 N HMQC-filtered 1 H-DQ experiment provides specific DQ-SQ correlation peaks for proton pairs that are in close proximities to the nitrogen sites, thereby achieving spectral filtration. Second, a proton-detected three-dimensional (3D) 1 H(DQ)- 14 N(SQ)- 1 H(SQ) experiment correlates 1 H(DQ)- 1 H(SQ) chemical shifts with 14 N shifts such that longer range N···H-H correlations are observed between protons and nitrogen atoms with internuclear NH distances exceeding 3 Å. Both 2D and 3D versions of the proposed experiment are demonstrated for an amino acid hydrochloride salt, l-histidine·HCl·H 2 O, and a DNA nucleoside, guanosine·2H 2 O. In the latter case, the achieved spectral filtration ensures that DQ cross peaks are only observed for guanine NH and CH8 1 H resonances and not ribose and water 1 H resonances, thus providing insight into the changes in the solid-state structure of this hydrate that occur over time; significant changes are observed in the NH and NH 2 1 H chemical shifts as compared to the freshly recrystallized sample previously studied by Reddy et al., Cryst. Growth Des. 2015, 15, 5945.

Solid effect in magic angle spinning dynamic nuclear polarization

NASA Astrophysics Data System (ADS)

Corzilius, Björn; Smith, Albert A.; Griffin, Robert G.

2012-08-01

For over five decades, the solid effect (SE) has been heavily utilized as a mechanism for performing dynamic nuclear polarization (DNP). Nevertheless, it has not found widespread application in contemporary, high magnetic field DNP experiments because SE enhancements display an ω _0 ^{ - 2} field dependence. In particular, for nominally forbidden zero and double quantum SE transitions to be partially allowed, it is necessary for mixing of adjacent nuclear spin states to occur, and this leads to the observed field dependence. However, recently we have improved our instrumentation and report here an enhancement of ɛ = 91 obtained with the organic radical trityl (OX063) in magic angle spinning experiments performed at 5 T and 80 K. This is a factor of 6-7 higher than previous values in the literature under similar conditions. Because the solid effect depends strongly on the microwave field strength, we attribute this large enhancement to larger microwave field strengths inside the sample volume, achieved with more efficient coupling of the gyrotron to the sample chamber. In addition, we develop a theoretical model to explain the dependence of the buildup rate of enhanced nuclear polarization and the steady-state enhancement on the microwave power. Buildup times and enhancements were measured as a function of 1H concentration for both trityl and Gd-DOTA. Comparison of the results indicates that for trityl the initial polarization step is the slower, rate-determining step. However, for Gd-DOTA the spread of nuclear polarization via homonuclear 1H spin diffusion is rate-limiting. Finally, we discuss the applicability of the solid effect at fields > 5 T and the requirements to address the unfavorable field dependence of the solid effect.

Study of lignification by noninvasive techniques in growing maize internodes. An investigation by Fourier transform infrared cross-polarization-magic angle spinning 13C-nuclear magnetic resonance spectroscopy and immunocytochemical transmission electron microscopy.

PubMed Central

Joseleau, J P; Ruel, K

1997-01-01

Noninvasive techniques were used for the study in situ of lignification in the maturing cell walls of the maize (Zea mays L.) stem. Within the longitudinal axis of a developing internode all of the stages of lignification can be found. The synthesis of the three types of lignins, p-hydroxyphenylpropane (H), guaiacyl (G), and syringyl (S), was investigated in situ by cross-polarization-magic angle spinning 13C-solid-state nuclear magnetic resonance, Fourier transform infrared spectroscopy, and immunocytochemical electron microscopy. The first lignin appearing in the parenchyma is of the G-type preceeding the incorporation of S nuclei in the later stages. However, in vascular bundles, typical absorption bands of S nuclei are visible in the Fourier transform infrared spectra at the earliest stage of lignification. Immunocytochemical determination of the three types of lignin in transmission electron microscopy was possible thanks to the use of antisera prepared against synthetic H, G, and the mixed GS dehydrogenative polymers (K. Ruel, O. Faix, J.P. Joseleau [1994] J Trace Microprobe Tech 12: 247-265). The specificity of the immunological probes demonstrated that there are differences in the relative temporal synthesis of the H, G, and GS lignins in the different tissues undergoing lignification. Considering the intermonomeric linkages predominating in the antigens used for the preparation of the immunological probes, the relative intensities of the labeling obtained provided, for the first time to our knowledge, information about the macromolecular nature of lignins (condensed versus noncondensed) in relation to their ultrastructural localization and development stage. PMID:9232887

Magic with Magic Squares.

ERIC Educational Resources Information Center

Wills, Herbert III

1989-01-01

Describes ways to make magic squares of 4 by 4 matrices. Presents two handouts: (1) Sets of 4 Numbers from 1 to 16 Whose Sum is 34; and (2) The Durer Square. Shows patterns which appeared in the magic squares, such as squares, chevrons, rhomboids, and trapezoids. (YP)

The Illusory Beliefs Inventory: a new measure of magical thinking and its relationship with obsessive compulsive disorder.

PubMed

Kingdon, Bianca L; Egan, Sarah J; Rees, Clare S

2012-01-01

Magical thinking has been proposed to have an aetiological role in obsessive compulsive disorder (OCD). To address the limitations of existing measures of magical thinking we developed and validated a new 24-item measure of magical thinking, the Illusory Beliefs Inventory (IBI). The validation sample comprised a total of 1194 individuals across two samples recruited via an Internet based survey. Factor analysis identified three subscales representing domains relevant to the construct of magical thinking: Magical Beliefs, Spirituality, and Internal State and Thought Action Fusion. The scale had excellent internal consistency and evidence of convergent and discriminant validity. Evidence of criterion-related concurrent validity confirmed that magical thinking is a cognitive domain associated with OCD and is largely relevant to neutralizing, obsessing and hoarding symptoms. It is important for future studies to extend the evidence of the psychometric properties of the IBI in new populations and to conduct longitudinal studies to examine the aetiological role of magical thinking.

Manufacturing Magic and Computational Creativity

PubMed Central

Williams, Howard; McOwan, Peter W.

2016-01-01

This paper describes techniques in computational creativity, blending mathematical modeling and psychological insight, to generate new magic tricks. The details of an explicit computational framework capable of creating new magic tricks are summarized, and evaluated against a range of contemporary theories about what constitutes a creative system. To allow further development of the proposed system we situate this approach to the generation of magic in the wider context of other areas of application in computational creativity in performance arts. We show how approaches in these domains could be incorporated to enhance future magic generation systems, and critically review possible future applications of such magic generating computers. PMID:27375533

Watching films with magical content facilitates creativity in children.

PubMed

Subbotsky, Eugene; Hysted, Claire; Jones, Nicola

2010-08-01

Two experiments examined the possible link between magical thinking and creativity in preschool children. In Exp. 1, 4- and 6-yr.-old children were shown a film with either a magical or nonmagical theme. Results indicated that the mean scores of children shown the magical film was significantly higher than that of children watching the nonmagical film on the majority of subsequent creativity tests for both age groups. This trend was also found for 6-yr.-olds' drawings of impossible items. In Exp. 2, Exp. 1 was replicated successfully with 6- and 8-yr.-old children. Exposing children to a film with a magical theme did not affect their beliefs about magic. The results were interpreted to accentuate the role of magical thinking in children's cognitive development. Classroom implications of the results were also discussed.

Polar and singular value decomposition of 3×3 magic squares

NASA Astrophysics Data System (ADS)

Trenkler, Götz; Schmidt, Karsten; Trenkler, Dietrich

2013-07-01

In this note, we find polar as well as singular value decompositions of a 3×3 magic square, i.e. a 3×3 matrix M with real elements where each row, column and diagonal adds up to the magic sum s of the magic square.

A method of incident angle estimation for high resolution spectral recovery in filter-array-based spectrometers

NASA Astrophysics Data System (ADS)

Kim, Cheolsun; Lee, Woong-Bi; Ju, Gun Wu; Cho, Jeonghoon; Kim, Seongmin; Oh, Jinkyung; Lim, Dongsung; Lee, Yong Tak; Lee, Heung-No

2017-02-01

In recent years, there has been an increasing interest in miniature spectrometers for research and development. Especially, filter-array-based spectrometers have advantages of low cost and portability, and can be applied in various fields such as biology, chemistry and food industry. Miniaturization in optical filters causes degradation of spectral resolution due to limitations on spectral responses and the number of filters. Nowadays, many studies have been reported that the filter-array-based spectrometers have achieved resolution improvements by using digital signal processing (DSP) techniques. The performance of the DSP-based spectral recovery highly depends on the prior information of transmission functions (TFs) of the filters. The TFs vary with respect to an incident angle of light onto the filter-array. Conventionally, it is assumed that the incident angle of light on the filters is fixed and the TFs are known to the DSP. However, the incident angle is inconstant according to various environments and applications, and thus TFs also vary, which leads to performance degradation of spectral recovery. In this paper, we propose a method of incident angle estimation (IAE) for high resolution spectral recovery in the filter-array-based spectrometers. By exploiting sparse signal reconstruction of the L1- norm minimization, IAE estimates an incident angle among all possible incident angles which minimizes the error of the reconstructed signal. Based on IAE, DSP effectively provides a high resolution spectral recovery in the filter-array-based spectrometers.

The Effect of Antitumor Glycosides on Glioma Cells and Tissues as Studied by Proton HR-MAS NMR Spectroscopy

PubMed Central

García-Álvarez, Isabel; Garrido, Leoncio; Romero-Ramírez, Lorenzo; Nieto-Sampedro, Manuel; Fernández-Mayoralas, Alfonso; Campos-Olivas, Ramón

2013-01-01

The effect of the treatment with glycolipid derivatives on the metabolic profile of intact glioma cells and tumor tissues, investigated using proton high resolution magic angle spinning (1H HR-MAS) nuclear magnetic resonance (NMR) spectroscopy, is reported here. Two compounds were used, a glycoside and its thioglycoside analogue, both showing anti-proliferative activity on glioma C6 cell cultures; however, only the thioglycoside exhibited antitumor activity in vivo. At the drug concentrations showing anti-proliferative activity in cell culture (20 and 40 µM), significant increases in choline containing metabolites were observed in the 1H NMR spectra of the same intact cells. In vivo experiments in nude mice bearing tumors derived from implanted C6 glioma cells, showed that reduction of tumor volume was associated with significant changes in the metabolic profile of the same intact tumor tissues; and were similar to those observed in cell culture. Specifically, the activity of the compounds is mainly associated with an increase in choline and phosphocholine, in both the cell cultures and tumoral tissues. Taurine, a metabolite that has been considered a biomarker of apoptosis, correlated with the reduction of tumor volume. Thus, the results indicate that the mode of action of the glycoside involves, at least in part, alteration of phospholipid metabolism, resulting in cell death. PMID:24194925

Fingolimod modulates multiple neuroinflammatory markers in a mouse model of Alzheimer’s disease

PubMed Central

Aytan, Nurgul; Choi, Ji-Kyung; Carreras, Isabel; Brinkmann, Volker; Kowall, Neil W.; Jenkins, Bruce G.; Dedeoglu, Alpaslan

2016-01-01

Sphingosine 1-phosphate (SP1) receptors may be attractive targets for modulation of inflammatory processes in neurodegenerative diseases. Recently fingolimod, a functional S1P1 receptor antagonist, was introduced for treatment of multiple sclerosis. We postulated that anti-inflammatory mechanisms of fingolimod might also be protective in Alzheimer’s disease (AD). Therefore, we treated a mouse model of AD, the 5xFAD model, with two doses of fingolimod (1 and 5 mg/kg/day) and measured the response of numerous markers of Aβ pathology as well as inflammatory markers and neurochemistry using biochemical, immunohistochemistry and high resolution magic angle spinning magnetic resonance spectroscopy (MRS). In mice at 3 months of age, we found that fingolimod decreased plaque density as well as soluble plus insoluble Aβ measured by ELISA. Fingolimod also decreased GFAP staining and the number of activated microglia. Taurine has been demonstrated to play a role as an endogenous anti-inflammatory molecule. Taurine levels, measured using MRS, showed a very strong inverse correlation with GFAP levels and ELISA measurements of Aβ, but not with plaque density or activated microglia levels. MRS also showed an effect of fingolimod on glutamate levels. Fingolimod at 1 mg/kg/day provided better neuroprotection than 5 mg/kg/day. Together, these data suggest a potential therapeutic role for fingolimod in AD. PMID:27117087

High-resolution NMR characterization of low abundance oligomers of amyloid-β without purification

NASA Astrophysics Data System (ADS)

Kotler, Samuel A.; Brender, Jeffrey R.; Vivekanandan, Subramanian; Suzuki, Yuta; Yamamoto, Kazutoshi; Monette, Martine; Krishnamoorthy, Janarthanan; Walsh, Patrick; Cauble, Meagan; Holl, Mark M. Banaszak; Marsh, E. Neil. G.; Ramamoorthy, Ayyalusamy

2015-07-01

Alzheimer’s disease is characterized by the misfolding and self-assembly of the amyloidogenic protein amyloid-β (Aβ). The aggregation of Aβ leads to diverse oligomeric states, each of which may be potential targets for intervention. Obtaining insight into Aβ oligomers at the atomic level has been a major challenge to most techniques. Here, we use magic angle spinning recoupling 1H-1H NMR experiments to overcome many of these limitations. Using 1H-1H dipolar couplings as a NMR spectral filter to remove both high and low molecular weight species, we provide atomic-level characterization of a non-fibrillar aggregation product of the Aβ1-40 peptide using non-frozen samples without isotopic labeling. Importantly, this spectral filter allows the detection of the specific oligomer signal without a separate purification procedure. In comparison to other solid-state NMR techniques, the experiment is extraordinarily selective and sensitive. A resolved 2D spectra could be acquired of a small population of oligomers (6 micrograms, 7% of the total) amongst a much larger population of monomers and fibers (93% of the total). By coupling real-time 1H-1H NMR experiments with other biophysical measurements, we show that a stable, primarily disordered Aβ1-40 oligomer 5-15 nm in diameter can form and coexist in parallel with the well-known cross-β-sheet fibrils.

FTIR and 1H MAS NMR investigations on the correlation between the frequency of stretching vibration and the chemical shift of surface OH groups of solids

NASA Astrophysics Data System (ADS)

Brunner, Eike; Karge, H. G.; Pfeifer, H.

1992-03-01

The study of surface hydroxyl groups of solids, especially of zeolites, belongs to the 'classical' topics of IR spectroscopy since physico-chemical information may be derived from the wavenumber (nu) OH of the stretching vibration of the different hydroxyls. On the other hand, the last decade has seen the development of high resolution solid-state NMR spectroscopy and through the use of the so-called magic-angle-spinning technique (MAS) the signals of different hydroxyl species can be resolved in the 1H NMR spectra of solids. The chemical shift (delta) H describing the position of these lines may be used as well as (nu) OH to characterize quantitatively the strength of acidity of surface OH groups of solids. In a first comparison of (nu) OH with (delta) H for several types of surface OH groups, a linear correlation between them could be found. The aim of this paper was to prove the validity of this correlation for a wide variety of hydroxyls. The IR measurements were carried out on a Perkin-Elmer FTIR spectrometer 1800 at the Fritz Haber Institute of the Max Planck Society, Berlin, and the 1H MAS NMR spectra were recorded on a Bruker MSL- 300 at the University of Leipzig.

Metabolic profiles of placenta in preeclampsia using HR-MAS MRS metabolomics.

PubMed

Austdal, Marie; Thomsen, Liv Cecilie Vestrheim; Tangerås, Line Haugstad; Skei, Bente; Mathew, Seema; Bjørge, Line; Austgulen, Rigmor; Bathen, Tone Frost; Iversen, Ann-Charlotte

2015-12-01

Preeclampsia is a heterogeneous gestational disease characterized by maternal hypertension and proteinuria, affecting 2-7% of pregnancies. The disorder is initiated by insufficient placental development, but studies characterizing the placental disease components are lacking. Our aim was to phenotype the preeclamptic placenta using high-resolution magic angle spinning nuclear magnetic resonance spectroscopy (HR-MAS MRS). Placental samples collected after delivery from women with preeclampsia (n = 19) and normotensive pregnancies (n = 15) were analyzed for metabolic biomarkers including amino acids, osmolytes, and components of the energy and phospholipid metabolism. The metabolic biomarkers were correlated to clinical characteristics and inflammatory biomarkers in the maternal sera. Principal component analysis showed inherent differences in placental metabolic profiles between preeclamptic and normotensive pregnancies. Significant differences in metabolic profiles were found between placentas from severe and non-severe preeclampsia, but not between preeclamptic pregnancies with fetal growth restricted versus normal weight neonates. The placental metabolites correlated with the placental stress marker sFlt-1 and triglycerides in maternal serum, suggesting variation in placental stress signaling between different placental phenotypes. HR-MAS MRS is a sensitive method for defining the placental disease component of preeclampsia, identifying several altered metabolic pathways. Placental HR-MAS MRS analysis may improve insight into processes affected in the preeclamptic placenta, and represents a novel long-required tool for a sensitive placental phenotyping of this heterogeneous disease. Copyright © 2015 Elsevier Ltd. All rights reserved.

Altered hepatic lipid metabolism in mice lacking both the melanocortin type 4 receptor and low density lipoprotein receptor.

PubMed

Lede, Vera; Meusel, Andrej; Garten, Antje; Popkova, Yulia; Penke, Melanie; Franke, Christin; Ricken, Albert; Schulz, Angela; Kiess, Wieland; Huster, Daniel; Schöneberg, Torsten; Schiller, Jürgen

2017-01-01

Obesity is often associated with dyslipidemia and hepatosteatosis. A number of animal models of non-alcoholic fatty liver disease (NAFLD) are established but they significantly differ in the molecular and biochemical changes depending on the genetic modification and diet used. Mice deficient for melanocortin type 4 receptor (Mc4rmut) develop hyperphagia, obesity, and subsequently NAFLD already under regular chow and resemble more closely the energy supply-driven obesity found in humans. This animal model was used to assess the molecular and biochemical consequences of hyperphagia-induced obesity on hepatic lipid metabolism. We analyzed transcriptome changes in Mc4rmut mice by RNA sequencing and used high resolution 1H magic angle spinning NMR spectroscopy and MALDI-TOF mass spectrometry to assess changes in the lipid composition. On the transcriptomic level we found significant changes in components of the triacylglycerol metabolism, unsaturated fatty acids biosynthesis, peroxisome proliferator-activated receptor signaling pathways, and lipid transport and storage compared to the wild-type. These findings were supported by increases in triacylglycerol, monounsaturated fatty acid, and arachidonic acid levels. The transcriptome signatures significantly differ from those of other NAFLD mouse models supporting the concept of hepatic subphenotypes depending on the genetic background and diet. Comparative analyses of our data with previous studies allowed for the identification of common changes and genotype-specific components and pathways involved in obesity-associated NAFLD.

Preparation of stationary phases for reversed-phase high-performance liquid chromatography using thermal treatments at high temperature.

PubMed

Vigna, Camila R M; Bottoli, Carla B G; Collins, Kenneth E; Collins, Carol H

2007-07-13

Batches of poly(methyloctylsiloxane) (PMOS)-loaded silica were prepared by deposition from a solution of PMOS into the pores of HPLC silica. Portions of PMOS-loaded silica were subjected to a thermal treatment at 100 degrees C for 24h (condition 1) in a tube furnace under a nitrogen atmosphere. After that, the material was heated for 4h at higher temperatures (150-400 degrees C) (condition 2). Heating at higher temperatures produces polymer bilayers. Non-immobilized and thermally treated stationary phases were characterized by percent carbon, (29)Si cross-polarization magic angle spinning nuclear magnetic resonance spectroscopy and reversed-phase chromatographic performance. The results show that thermal treatment between 150 and 300 degrees C accelerates the immobilization process, possibly due to some bond breaking of the polysiloxane, with formation of strong linkages to the surface of the support, resulting in more complete coverage of the silica. The chromatographic results show an improvement of efficiency with the increase of the temperature of condition 2 up to 300 degrees C and an increase in the resolution of the components, mainly for the phase heated at 300 degrees C. Such results demonstrate that a two-step thermal treatment (100 degrees C then 150-300 degrees C) produces stationary phases with good properties for use in reversed-phase high-performance liquid chromatography.

Fingolimod modulates multiple neuroinflammatory markers in a mouse model of Alzheimer's disease.

PubMed

Aytan, Nurgul; Choi, Ji-Kyung; Carreras, Isabel; Brinkmann, Volker; Kowall, Neil W; Jenkins, Bruce G; Dedeoglu, Alpaslan

2016-04-27

Sphingosine 1-phosphate (SP1) receptors may be attractive targets for modulation of inflammatory processes in neurodegenerative diseases. Recently fingolimod, a functional S1P1 receptor antagonist, was introduced for treatment of multiple sclerosis. We postulated that anti-inflammatory mechanisms of fingolimod might also be protective in Alzheimer's disease (AD). Therefore, we treated a mouse model of AD, the 5xFAD model, with two doses of fingolimod (1 and 5 mg/kg/day) and measured the response of numerous markers of Aβ pathology as well as inflammatory markers and neurochemistry using biochemical, immunohistochemistry and high resolution magic angle spinning magnetic resonance spectroscopy (MRS). In mice at 3 months of age, we found that fingolimod decreased plaque density as well as soluble plus insoluble Aβ measured by ELISA. Fingolimod also decreased GFAP staining and the number of activated microglia. Taurine has been demonstrated to play a role as an endogenous anti-inflammatory molecule. Taurine levels, measured using MRS, showed a very strong inverse correlation with GFAP levels and ELISA measurements of Aβ, but not with plaque density or activated microglia levels. MRS also showed an effect of fingolimod on glutamate levels. Fingolimod at 1 mg/kg/day provided better neuroprotection than 5 mg/kg/day. Together, these data suggest a potential therapeutic role for fingolimod in AD.

Transport Properties of Ibuprofen Encapsulated in Cyclodextrin Nanosponge Hydrogels: A Proton HR-MAS NMR Spectroscopy Study.

PubMed

Ferro, Monica; Castiglione, Franca; Punta, Carlo; Melone, Lucio; Panzeri, Walter; Rossi, Barbara; Trotta, Francesco; Mele, Andrea

2016-08-15

The chemical cross-linking of β-cyclodextrin (β-CD) with ethylenediaminetetraacetic dianhydride (EDTA) led to branched polymers referred to as cyclodextrin nanosponges (CDNSEDTA). Two different preparations are described with 1:4 and 1:8 CD-EDTA molar ratios. The corresponding cross-linked polymers were contacted with 0.27 M aqueous solution of ibuprofen sodium salt (IP) leading to homogeneous, colorless, drug loaded hydrogels. The systems were characterized by high resolution magic angle spinning (HR-MAS) NMR spectroscopy. Pulsed field gradient spin echo (PGSE) NMR spectroscopy was used to determine the mean square displacement (MSD) of IP inside the polymeric gel at different observation times td. The data were further processed in order to study the time dependence of MSD: MSD = f(td). The proposed methodology is useful to characterize the different diffusion regimes that, in principle, the solute may experience inside the hydrogel, namely normal or anomalous diffusion. The full protocols including the polymer preparation and purification, the obtainment of drug-loaded hydrogels, the NMR sample preparation, the measurement of MSD by HR-MAS NMR spectroscopy and the final data processing to achieve the time dependence of MSD are here reported and discussed. The presented experiments represent a paradigmatic case and the data are discussed in terms of innovative approach to the characterization of the transport properties of an encapsulated guest within a polymeric host of potential application for drug delivery.

High-resolution NMR characterization of low abundance oligomers of amyloid-β without purification

PubMed Central

Kotler, Samuel A.; Brender, Jeffrey R.; Vivekanandan, Subramanian; Suzuki, Yuta; Yamamoto, Kazutoshi; Monette, Martine; Krishnamoorthy, Janarthanan; Walsh, Patrick; Cauble, Meagan; Holl, Mark M. Banaszak; Marsh, E. Neil. G.; Ramamoorthy, Ayyalusamy

2015-01-01

Alzheimer’s disease is characterized by the misfolding and self-assembly of the amyloidogenic protein amyloid-β (Aβ). The aggregation of Aβ leads to diverse oligomeric states, each of which may be potential targets for intervention. Obtaining insight into Aβ oligomers at the atomic level has been a major challenge to most techniques. Here, we use magic angle spinning recoupling 1H-1H NMR experiments to overcome many of these limitations. Using 1H-1H dipolar couplings as a NMR spectral filter to remove both high and low molecular weight species, we provide atomic-level characterization of a non-fibrillar aggregation product of the Aβ1-40 peptide using non-frozen samples without isotopic labeling. Importantly, this spectral filter allows the detection of the specific oligomer signal without a separate purification procedure. In comparison to other solid-state NMR techniques, the experiment is extraordinarily selective and sensitive. A resolved 2D spectra could be acquired of a small population of oligomers (6 micrograms, 7% of the total) amongst a much larger population of monomers and fibers (93% of the total). By coupling real-time 1H-1H NMR experiments with other biophysical measurements, we show that a stable, primarily disordered Aβ1-40 oligomer 5–15 nm in diameter can form and coexist in parallel with the well-known cross-β-sheet fibrils. PMID:26138908

High-resolution NMR characterization of low abundance oligomers of amyloid-β without purification.

PubMed

Kotler, Samuel A; Brender, Jeffrey R; Vivekanandan, Subramanian; Suzuki, Yuta; Yamamoto, Kazutoshi; Monette, Martine; Krishnamoorthy, Janarthanan; Walsh, Patrick; Cauble, Meagan; Holl, Mark M Banaszak; Marsh, E Neil G; Ramamoorthy, Ayyalusamy

2015-07-03

Alzheimer's disease is characterized by the misfolding and self-assembly of the amyloidogenic protein amyloid-β (Aβ). The aggregation of Aβ leads to diverse oligomeric states, each of which may be potential targets for intervention. Obtaining insight into Aβ oligomers at the atomic level has been a major challenge to most techniques. Here, we use magic angle spinning recoupling (1)H-(1)H NMR experiments to overcome many of these limitations. Using (1)H-(1)H dipolar couplings as a NMR spectral filter to remove both high and low molecular weight species, we provide atomic-level characterization of a non-fibrillar aggregation product of the Aβ1-40 peptide using non-frozen samples without isotopic labeling. Importantly, this spectral filter allows the detection of the specific oligomer signal without a separate purification procedure. In comparison to other solid-state NMR techniques, the experiment is extraordinarily selective and sensitive. A resolved 2D spectra could be acquired of a small population of oligomers (6 micrograms, 7% of the total) amongst a much larger population of monomers and fibers (93% of the total). By coupling real-time (1)H-(1)H NMR experiments with other biophysical measurements, we show that a stable, primarily disordered Aβ1-40 oligomer 5-15 nm in diameter can form and coexist in parallel with the well-known cross-β-sheet fibrils.

New biosourced chiral molecularly imprinted polymer: Synthesis, characterization, and evaluation of the recognition capacity of methyltestosterone.

PubMed

Saadaoui, Asma; Sanglar, Corinne; Medimagh, Raouf; Bonhomme, Anne; Baudot, Robert; Chatti, Saber; Marque, Sylvain; Prim, Damien; Zina, Mongia Saïd; Casabianca, Herve

2017-04-01

New biosourced chiral cross-linkers were reported for the first time in the synthesis of methyltestosterone (MT) chiral molecularly imprinted polymers (cMIPs). Isosorbide and isomannide, known as 1,4:3,6-dianhydrohexitols, were selected as starting diols. The cMIPs were synthesized following a noncovalent approach via thermal radical polymerization and monitored by Raman spectroscopy. These cross-linkers were fully characterized by 1 H and 13 C nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry. The cross-polarization magic angle spinning 13 C NMR, Fourier transform infrared spectroscopy, scanning electron microscopy, and specific surface areas following the Brunauer-Emmett-Teller (BET) method were used to characterize the cMIPs. The effect of stereochemistry of cross-linkers on the reactivity of polymerization, morphology, and adsorption-recognition properties of the MIP was evaluated. The results showed that the cMIP exhibited an obvious improvement in terms of rebinding capacity for MT as compared with the nonimprinted polymer (NIP). The highest binding capacity was observed for cMIP-Is (27.298 mg g -1 ) for high concentrations (500 mg L -1 ). However, the isomannide homologue cMIP-Im showed higher recovery-up to 65% and capacity for low concentrations (15 mg L -1 ). The experimental data were properly fitted by the Freundlich adsorption isothermal model. Copyright © 2016 John Wiley & Sons, Ltd.

High-resolution solid-state 13C NMR spectroscopy of the paramagnetic metal-organic frameworks, STAM-1 and HKUST-1.

PubMed

Dawson, Daniel M; Jamieson, Lauren E; Mohideen, M Infas H; McKinlay, Alistair C; Smellie, Iain A; Cadou, Romain; Keddie, Neil S; Morris, Russell E; Ashbrook, Sharon E

2013-01-21

Solid-state (13)C magic-angle spinning (MAS) NMR spectroscopy is used to investigate the structure of the Cu(II)-based metal-organic frameworks (MOFs), HKUST-1 and STAM-1, and the structural changes occurring within these MOFs upon activation (dehydration). NMR spectroscopy is an attractive technique for the investigation of these materials, owing to its high sensitivity to local structure, without any requirement for longer-range order. However, interactions between nuclei and unpaired electrons in paramagnetic systems (e.g., Cu(II)-based MOFs) pose a considerable challenge, not only for spectral acquisition, but also in the assignment and interpretation of the spectral resonances. Here, we exploit the rapid T(1) relaxation of these materials to obtain (13)C NMR spectra using a spin-echo pulse sequence at natural abundance levels, and employ frequency-stepped acquisition to ensure uniform excitation of resonances over a wide frequency range. We then utilise selective (13)C isotopic labelling of the organic linker molecules to enable an unambiguous assignment of NMR spectra of both MOFs for the first time. We show that the monomethylated linker can be recovered from STAM-1 intact, demonstrating not only the interesting use of this MOF as a protecting group, but also the ability (for both STAM-1 and HKUST-1) to recover isotopically-enriched linkers, thereby reducing significantly the overall cost of the approach.

Optimization of metabolite basis sets prior to quantitation in magnetic resonance spectroscopy: an approach based on quantum mechanics

NASA Astrophysics Data System (ADS)

Lazariev, A.; Allouche, A.-R.; Aubert-Frécon, M.; Fauvelle, F.; Piotto, M.; Elbayed, K.; Namer, I.-J.; van Ormondt, D.; Graveron-Demilly, D.

2011-11-01

High-resolution magic angle spinning (HRMAS) nuclear magnetic resonance (NMR) is playing an increasingly important role for diagnosis. This technique enables setting up metabolite profiles of ex vivo pathological and healthy tissue. The need to monitor diseases and pharmaceutical follow-up requires an automatic quantitation of HRMAS 1H signals. However, for several metabolites, the values of chemical shifts of proton groups may slightly differ according to the micro-environment in the tissue or cells, in particular to its pH. This hampers the accurate estimation of the metabolite concentrations mainly when using quantitation algorithms based on a metabolite basis set: the metabolite fingerprints are not correct anymore. In this work, we propose an accurate method coupling quantum mechanical simulations and quantitation algorithms to handle basis-set changes. The proposed algorithm automatically corrects mismatches between the signals of the simulated basis set and the signal under analysis by maximizing the normalized cross-correlation between the mentioned signals. Optimized chemical shift values of the metabolites are obtained. This method, QM-QUEST, provides more robust fitting while limiting user involvement and respects the correct fingerprints of metabolites. Its efficiency is demonstrated by accurately quantitating 33 signals from tissue samples of human brains with oligodendroglioma, obtained at 11.7 tesla. The corresponding chemical shift changes of several metabolites within the series are also analyzed.

The MAGIC (Manually Assisted Gaming of Integrated Combat) Model,

DTIC Science & Technology

1982-05-01

IP -6 7 6 7 Zo - A O - ?G O 6 7 9 N L mhhhhh1h8I 1-I THE MAGIC (MANUALLY ASSISTED GAMING OF INTEGRATED COMBAT) MODEL Milton G. Weiner May 1982 L io...Corporation Santa Monica, California 90406 - - ~-. - - -i 77 THE MAGIC (MANUALLY ASSISTED GAMING OF INTEGRATED COMBAT) MODEL Milton G. Weiner May 1982 THE... MAGIC (MANUALLY ASSISTED GAMING OF INTEGRATED COMBAT) MODEL Milton G. Weiner The Rand Corporation, Santa Monica, California The MAGIC model isn’Vt

The Advanced Gamma-ray Imaging System (AGIS)-Simulation Studies

NASA Astrophysics Data System (ADS)

Maier, G.; Buckley, J.; Bugaev, V.; Fegan, S.; Funk, S.; Konopelko, A.; Vassiliev, V. V.

2008-12-01

The Advanced Gamma-ray Imaging System (AGIS) is a US-led concept for a next-generation instrument in ground-based very-high-energy gamma-ray astronomy. The most important design requirement for AGIS is a sensitivity of about 10 times greater than current observatories like Veritas, H.E.S.S or MAGIC. We present results of simulation studies of various possible designs for AGIS. The primary characteristics of the array performance, collecting area, angular resolution, background rejection, and sensitivity are discussed.

Magical ideation is related to questionnaire but not behavioural measures of handedness.

PubMed

Grimshaw, Gina M; Yelle, Serena K; Schoger, Jamie; Bright, Kathleen S

2008-01-01

Magical ideation has repeatedly been shown to be related to handedness, with mixed-handers exhibiting higher levels of magical thinking. However, most previous research has assessed hand preference with a questionnaire measure, leaving open the possibility that the correlation reflects some aspect of questionnaire-taking behaviour and not an underlying neuropsychological relationship. The present study addressed this issue by administering the Magical Ideation Scale (Eckblad & Chapman, 1983), the Waterloo Handedness Questionnaire-Revised (Elias, Bryden, & Bulman-Fleming, 1998), and a manual dot-filling task (Tapley & Bryden, 1985) as a behavioural measure of handedness to an undergraduate student sample. The expected relationship between magical ideation and handedness as assessed by the questionnaire was observed. However, magical ideation was not related to the behavioural measure of handedness. Results cast doubt on a neuropsychological interpretation of the relationship between handedness and magical ideation in sub-clinical populations.

On Super Edge-magic Total Labeling of Modified Watermill Graph

NASA Astrophysics Data System (ADS)

Nurdin; Ungko, T. S.; Gormantara, J.; Abdullah, A.; Aulyah, S.; Nikita

2018-03-01

An edge-magic total labeling on a graph G is one-to-one map from V(G) ∪ E(G) onto the set of integers 1,2, ...,ν + e, where ν = |V(G)| and e = |E(G)|, with the property that, given any edge uv, f(u) + f(u, ν}) + f(ν) = k for every u,v ∈ V(G), and k is called magic valuation. An edge-magic total labeling f is called super edge-magic total if f(v(G)) = {1,2 ...,|V(G)|} and f(E(G)) = {|V(G)| + 1, |V(G)| + 2,... |V(G) + E(G)|}. In this paper we investigate edge-magic total labeling of a new graph called modified Watermill graph. Furthermore, the magic valuation of the modified Watermill graph WM(n) is k=\\frac{1}{2}(21n+3), for n odd, n ≥ 3.

78 FR 7464 - Large Scale Networking (LSN)-Middleware And Grid Interagency Coordination (MAGIC) Team

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-01

... Coordination (MAGIC) Team AGENCY: The Networking and Information Technology Research and Development (NITRD... (703) 292-4873. Date/Location: The MAGIC Team meetings are held on the first Wednesday of each month, 2... basis. WebEx participation is available for each meeting. Please reference the MAGIC Team Web site for...

Z3 -vertex magic total labeling and Z3 -edge magic total labelingfor the extended duplicate graph of quadrilateral snake

NASA Astrophysics Data System (ADS)

Indira, P.; Selvam, B.; Thirusangu, K.

2018-04-01

Based on the works of Kotzig, Rosa and MacDougall et.al., we present algorithms and prove the existence of Z3-vertex magic total labeling and Z3-edge magic total labeling for the extended duplicate graph of quadrilateral snake.

Relationships between magical thinking, obsessive-compulsiveness and other forms of anxiety in a sample of non-clinical children.

PubMed

Simonds, Laura M; Demetre, James D; Read, Cristina

2009-06-01

Despite the obvious phenomenological similarities between magical thinking and obsessive-compulsiveness, the relationship between them has been the subject of few empirical investigations in samples of children. The present study aimed to examine the relationship between a general epistemic stance towards magical causation and tendencies towards obsessive-compulsiveness in a non-clinical sample of schoolchildren. One-hundred and two children, aged between 5 and 10 years (48 boys and 54 girls), completed questionnaire measures designed to assess magical thinking, obsessive-compulsiveness, and other forms of anxiety. School teachers completed a measure of strengths and difficulties for each child. General belief in magical causation was correlated with all types of anxiety, not just obsessive-compulsiveness, with significant correlations shown for boys in the sample, but not girls. General belief in magical causation contributed little to the prediction of obsessive-compulsiveness beyond general anxiety. In this study, a general epistemic stance towards magical causation did not differentiate obsessive-compulsiveness from other anxiety dimensions. The findings are considered in the context of developmental theories of magical and scientific causal reasoning.

57Fe Mössbauer study of the asbestiform silicates balangeroite and carlosturanite

NASA Astrophysics Data System (ADS)

Deriu, Antonio; Ferraris, Giovanni; Belluso, Elena

1994-08-01

57FeMössbauer spectra of the two silicate minerals balangeroite (BAL) and carlosturanite (CST) have been collected at 80 and 295 K under normal and magic angle geometry. For both minerals the spectra have been fitted with two ferrous and two ferric doublets; Fe2+ accounts for 80 and 62% of Fetot in Bal and CST, respectively. The number of doublets used to fit the spectra supports the hypotheses that: (i) in the serpentine-like structure of CST iron occupies only octahedra which lie between the tetrahedral silicate strips; (ii) the octahedral framework of BAL (actually monoclinic) is satisfactorily described with an orthorhombic sub-cell.

Combining Nuclear Magnetic Resonance Spectroscopy and Density Functional Theory Calculations to Characterize Carvedilol Polymorphs.

PubMed

Rezende, Carlos A; San Gil, Rosane A S; Borré, Leandro B; Pires, José Ricardo; Vaiss, Viviane S; Resende, Jackson A L C; Leitão, Alexandre A; De Alencastro, Ricardo B; Leal, Katia Z

2016-09-01

The experiments of carvedilol form II, form III, and hydrate by (13)C and (15)N cross-polarization magic-angle spinning (CP MAS) are reported. The GIPAW (gauge-including projector-augmented wave) method from DFT (density functional theory) calculations was used to simulate (13)C and (15)N chemical shifts. A very good agreement was found for the comparison between the global results of experimental and calculated nuclear magnetic resonance (NMR) chemical shifts for carvedilol polymorphs. This work aims a comprehensive understanding of carvedilol crystalline forms employing solution and solid-state NMR as well as DFT calculations. Copyright © 2016. Published by Elsevier Inc.

The investigation of the effect of thermal treatment on bentonites from Turkey with Fourier transform infrared and solid state nuclear magnetic resonance spectroscopic methods.

PubMed

Erdoğan Alver, Burcu; Alver, Ozgür

2012-08-01

There is a great deal of interest in the building industry in burned clays for production of building materials. Therefore, the effect of heat treatment on natural bentonite from Turkey was investigated by Fourier transform infrared (FT-IR) between the region of 4000-400cm(-1) and (29)Si, (27)Al magic angle spinning nuclear magnetic resonance (MAS NMR) measurement techniques at various temperatures between 200 and 700°C for 2h. The structural changes were also investigated upon heat treatment. Copyright © 2012 Elsevier B.V. All rights reserved.

Near-Infrared (NIR) Spectroscopy of Synthetic Hydroxyapatites and Human Dental Tissues.

PubMed

Kolmas, Joanna; Marek, Dariusz; Kolodziejski, Waclaw

2015-08-01

Near-infrared spectroscopy (NIR) was used to analyze synthetic hydroxyapatite calcined at various temperatures, synthetic carbonated hydroxyapatite, and human hard dental tissues (enamel and dentin). The NIR bands of those materials in the combination, first-overtone, and second-overtone spectral regions were assigned and evaluated for structural characterization. They were attributed to adsorbed and structural water, structural hydroxyl (OH) groups and surface P-OH groups. The NIR spectral features were quantitatively discussed in view of proton solid-state magic-angle spinning nuclear magnetic resonance ((1)H MAS NMR) results. We conclude that the NIR spectra of apatites are useful in the structural characterization of synthetic and biogenic apatites.

High resolution quantitative phase imaging of live cells with constrained optimization approach

NASA Astrophysics Data System (ADS)

Pandiyan, Vimal Prabhu; Khare, Kedar; John, Renu

2016-03-01

Quantitative phase imaging (QPI) aims at studying weakly scattering and absorbing biological specimens with subwavelength accuracy without any external staining mechanisms. Use of a reference beam at an angle is one of the necessary criteria for recording of high resolution holograms in most of the interferometric methods used for quantitative phase imaging. The spatial separation of the dc and twin images is decided by the reference beam angle and Fourier-filtered reconstructed image will have a very poor resolution if hologram is recorded below a minimum reference angle condition. However, it is always inconvenient to have a large reference beam angle while performing high resolution microscopy of live cells and biological specimens with nanometric features. In this paper, we treat reconstruction of digital holographic microscopy images as a constrained optimization problem with smoothness constraint in order to recover only complex object field in hologram plane even with overlapping dc and twin image terms. We solve this optimization problem by gradient descent approach iteratively and the smoothness constraint is implemented by spatial averaging with appropriate size. This approach will give excellent high resolution image recovery compared to Fourier filtering while keeping a very small reference angle. We demonstrate this approach on digital holographic microscopy of live cells by recovering the quantitative phase of live cells from a hologram recorded with nearly zero reference angle.

Analysis of axial spatial resolution in a variable resolution x-ray cone beam CT (VRX-CBCT) system

NASA Astrophysics Data System (ADS)

Dahi, Bahram; Keyes, Gary S.; Rendon, David A.; DiBianca, Frank A.

2008-03-01

The Variable Resolution X-ray (VRX) technique has been successfully used in a Cone-Beam CT (CBCT) system to increase the spatial resolution of CT images in the transverse plane. This was achieved by tilting the Flat Panel Detector (FPD) to smaller vrx y angles in a VRX Cone Beam CT (VRX-CBCT) system. In this paper, the effect on the axial spatial resolution of CT images created by the VRX-CBCT system is examined at different vrx x angles, where vrx x is the tilting angle of the FPD about its x-axis. An amorphous silicon FPD with a CsI scintillator is coupled with a micro-focus x-ray tube to form a CBCT. The FPD is installed on a rotating frame that allows rotation of up to 90° about x and y axes of the FPD. There is no rotation about the z-axis (i.e. normal to the imaging surface). Tilting the FPD about its x-axis (i.e. decreasing the vrx x angle) reduces both the width of the line-spread function and the sampling distance by a factor of sin vrx x, thereby increasing the theoretical detector pre-sampling spatial resolution proportionately. This results in thinner CT slices that in turn help increase the axial spatial resolution of the CT images. An in-house phantom is used to measure the MTF of the reconstructed CT images at different vrx x angles.

High-resolution scanning precession electron diffraction: Alignment and spatial resolution.

PubMed

Barnard, Jonathan S; Johnstone, Duncan N; Midgley, Paul A

2017-03-01

Methods are presented for aligning the pivot point of a precessing electron probe in the scanning transmission electron microscope (STEM) and for assessing the spatial resolution in scanning precession electron diffraction (SPED) experiments. The alignment procedure is performed entirely in diffraction mode, minimising probe wander within the bright-field (BF) convergent beam electron diffraction (CBED) disk and is used to obtain high spatial resolution SPED maps. Through analysis of the power spectra of virtual bright-field images extracted from the SPED data, the precession-induced blur was measured as a function of precession angle. At low precession angles, SPED spatial resolution was limited by electronic noise in the scan coils; whereas at high precession angles SPED spatial resolution was limited by tilt-induced two-fold astigmatism caused by the positive spherical aberration of the probe-forming lens. Copyright © 2016 Elsevier B.V. All rights reserved.

The Magic of Magic: The Effect of Magic Tricks on Subsequent Engagement with Lecture Material

ERIC Educational Resources Information Center

Moss, Simon A.; Irons, Melanie; Boland, Martin

2017-01-01

Background and aims: Lecturers often present entertaining videos, or organize a variety of amusing demonstrations, to foster student engagement or to encourage critical analysis. Magic tricks, in particular, have been shown to activate neural circuits that underpin motivation or problem-solving and, therefore, could be beneficial during lectures.…

Characterization of completely k-magic regular graphs

NASA Astrophysics Data System (ADS)

Eniego, A. A.; Garces, I. J. L.

2017-10-01

Let k ∈ ℕ and c ∈ ℤ k . A graph G is said to be c-sum k-magic if there is a labeling ℓ : E(G) → ℤ k {0} such that Σ u∈N(v) ℓ(uv) ≡ c (mod k) for every vertex v of G, where N(v) is the neighborhood of v in G. We say that G is completely k-magic whenever it is c-sum k-magic for every c ∈ ℤ k . In this paper, we characterize all completely k-magic regular graphs.

Experimental Investigation of the Electronic Properties of Twisted Bilayer Graphene by STM and STS

NASA Astrophysics Data System (ADS)

Yin, Longjing; Qiao, Jiabin; Wang, Wenxiao; Zuo, Weijie; He, Lin

The electronic properties of graphene multilayers depend sensitively on their stacking order. A twisted angle is treated as a unique degree of freedom to tune the electronic properties of graphene system. Here we study electronic structures of the twisted bilayers by scanning tunneling microscopy (STM) and spectroscopy (STS). We demonstrate that the interlayer coupling strength affects both the Van Hove singularities and the Fermi velocity of twisted bilayers dramatically. This removes the discrepancy about the Fermi velocity renormalization in the twisted bilayers and provides a consistent interpretation of all current data. Moreover, we report the experimental evidence for non-Abelian gauge potentials in twisted graphene bilayers by STM and STS. At a magic twisted angle, about 1.11°, a pronounced sharp peak is observed in the tunnelling spectra due to the action of the non-Abelian gauge fields. Because of the effective non-Abelian gauge fields, the rotation angle could transfer the charge carriers in the twisted bilayers from massless Dirac fermions into well localized electrons, or vice versa, efficiently. This provides a new route to tune the electronic properties of graphene systems, which will be essential in future graphene nanoelectronics.

Sleightly Persuasive: Using Magic To Teach Principles of Persuasion.

ERIC Educational Resources Information Center

Frasier, C. Jay

Magic can be used in the communication classroom as a means for introducing and/or illustrating the subject of persuasion. A magical effect which fools the class can lead to an early discussion of the need to be a critical consumer of persuasive messages. Magic can also be used to introduce the subject of ethics in persuasion. Each student can be…

Science meets magic: photonic metamaterials

NASA Astrophysics Data System (ADS)

Ozbay, Ekmel

2012-05-01

The word "magic" is usually associated with movies, fiction, children stories, etc. but seldom with the natural sciences. Recent advances in metamaterials have changed this notion, in which we can now speak of "almost magical" properties that scientists could only dream about only a decade ago. In this article, we review some of the recent "almost magical" progress in the field of meta-materials.

Science meets magic: photonic metamaterials

NASA Astrophysics Data System (ADS)

Ozbay, Ekmel

2012-03-01

The word "magic" is usually associated with movies, fiction, children stories, etc. but seldom with the natural sciences. Recent advances in metamaterials have changed this notion, in which we can now speak of "almost magical" properties that scientists could only dream about only a decade ago. In this article, we review some of the recent "almost magical" progress in the field of meta-materials.

Magical Ideation, Creativity, Handedness, and Cerebral Asymmetries: A Combined Behavioural and fMRI Study

ERIC Educational Resources Information Center

Badzakova-Trajkov, Gjurgjica; Haberling, Isabelle S.; Corballis, Michael C.

2011-01-01

Magical ideation has been shown to be related to measures of hand preference, in which those with mixed handedness exhibit higher levels of magical ideation than those with either consistent left- or right-handedness. It is unclear whether the relation between magical ideation and hand preference is the result of a bias in questionnaire-taking…

Compact Magic-T using microstrip-slotline transitions

NASA Technical Reports Server (NTRS)

U-Yen, Kongpop (Inventor); Wollack, Edward J. (Inventor); Doiron, Terence (Inventor); Moseley, Samuel H. (Inventor)

2010-01-01

The design of a compact low-loss Magic-T is described. The planar Magic-T incorporates a compact microstrip-slotline tee junction and small microstrip-slotline transition area to reduce slotline radiation. The Magic-T produces broadband in-phase and out-of-phase power combiner/divider responses, has low in-band insertion loss, and small in-band phase and amplitude imbalance.

Measurement method for roll angular displacement with a high resolution by using diffraction gratings and a heterodyne interferometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Shanzhi, E-mail: shanzhit@gmail.com; School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049; Wang, Zhao

The roll angle measurement is difficult to be achieved directly using a typical commercial interferometer due to its low sensitivity in axial direction, where the axial direction is orthogonal to the plane of the roll angular displacement. A roll angle measurement method combined diffraction gratings with a laser heterodyne interferometer is discussed in this paper. The diffraction grating placed in the plane of a roll angular displacement and the interferometer arranged in the plane's orthogonal direction, constitute the measurement pattern for the roll angle with high resolution. The roll angular displacement, considered as the linear, can be tested precisely whenmore » the corresponding angle is very small. Using the proposed method, the angle roll measurement obtains the high resolution of 0.002{sup ″}. Experiment has proved its feasibility and practicability.« less

Magical ideation associated social cognition in adolescents: signs of a negative facial affect recognition deficit.

PubMed

Canli, Derya; Ozdemir, Hatice; Kocak, Orhan Murat

2015-08-01

Studies provide evidence for impaired social cognition in schizotypy and its association with negative symptoms. Cognitive features related to magical ideation - a component of the positive dimension of schizotypy - have been less investigated. We aimed to assess social cognitive functioning among adolescents with high magical ideation scores, mainly focusing on face and emotion recognition. 22 subjects with magical ideation scale scores above the cut off level and 22 controls with lowest scores from among 250 students screened with this scale were included in the study. A face and emotion recognition n-back test, the empathy quotient, theory of mind tests and the Physical Anhedonia Scale were applied to both magical ideation and control groups. The magical ideation group performed significantly worse than controls on both face and emotion recognition tests. Emotion recognition performance was found to be affected by memory load, with sadness, among emotions, revealing a difference between the two groups. Empathy and theory of mind tests did not distinguish the magical ideation group from controls. Our findings provide evidence for a deficit in negative emotion recognition affected by memory load associated with magical ideation in adolescents. Copyright © 2015 Elsevier Inc. All rights reserved.

Magical ideation, creativity, handedness, and cerebral asymmetries: a combined behavioural and fMRI study.

PubMed

Badzakova-Trajkov, Gjurgjica; Häberling, Isabelle S; Corballis, Michael C

2011-08-01

Magical ideation has been shown to be related to measures of hand preference, in which those with mixed handedness exhibit higher levels of magical ideation than those with either consistent left- or right-handedness. It is unclear whether the relation between magical ideation and hand preference is the result of a bias in questionnaire-taking behaviour or of some neuropsychological concomitant of cerebral specialization. We sought to replicate this finding and further investigate how magical ideation is related to other measures of laterality, including handedness based on finger-tapping performance, and cerebral asymmetries for language, spatial judgment, and face processing as revealed by fMRI. Creative achievement was also assessed by questionnaire and correlated with magical ideation and the other measures. Magical ideation and creativity were positively correlated, and both were negatively correlated with absolute hand preference but not with hand performance or with any of the cerebral asymmetries being assessed. The results do not support the notion that the observed association between magical ideation, creativity and hand preference has a neuropsychological explanation based on reduced cerebral lateralization. Copyright © 2011 Elsevier Ltd. All rights reserved.

Old and New Magic Numbers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Talmi, Igal

2008-11-11

The discovery of magic numbers led to the shell model. They indicated closure of major shells and are robust: proton magic numbers are rather independent of the occupation of neutron orbits and vice versa. Recently the magic property became less stringent and we hear a lot about the discovery of new magic numbers. These, however, indicate sub-shell closures and strongly depend on occupation numbers and hence, may be called quasi-magic numbers. Some of these have been known for many years and the mechanism for their appearance as well as disappearance, was well understood within the simple shell model. The situationmore » will be illustrated by a few examples which demonstrate the simple features of the shell model. Will this simplicity emerge from the complex computations of nuclear many-body theory?.« less

Up Close and Personal

NASA Image and Video Library

2014-05-08

This image is one of the highest-resolution MDIS observations to date! Many craters of varying degradation states are visible, as well as gentle terrain undulations. Very short exposure times are needed to make these low-altitude observations while the spacecraft is moving quickly over the surface; thus the images are slightly noisier than typical MDIS images. This image was acquired as a high-resolution targeted observation. Targeted observations are images of a small area on Mercury's surface at resolutions much higher than the 200-meter/pixel morphology base map. It is not possible to cover all of Mercury's surface at this high resolution, but typically several areas of high scientific interest are imaged in this mode each week. Date acquired: March 15, 2014 Image Mission Elapsed Time (MET): 37173522 Image ID: 5936740 Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS) Center Latitude: 71.91° Center Longitude: 232.7° E Resolution: 5 meters/pixel Scale: The image is approximately 8.3 km (5.2 mi.) across. Incidence Angle: 79.4° Emission Angle: 4.0° Phase Angle: 83.4° http://photojournal.jpl.nasa.gov/catalog/PIA18370

The magic words: Using computers to uncover mental associations for use in magic trick design.

PubMed

Williams, Howard; McOwan, Peter W

2017-01-01

The use of computational systems to aid in the design of magic tricks has been previously explored. Here further steps are taken in this direction, introducing the use of computer technology as a natural language data sourcing and processing tool for magic trick design purposes. Crowd sourcing of psychological concepts is investigated; further, the role of human associative memory and its exploitation in magical effects is explored. A new trick is developed and evaluated: a physical card trick partially designed by a computational system configured to search for and explore conceptual spaces readily understood by spectators.

Auto-calibrated scanning-angle prism-type total internal reflection microscopy for nanometer-precision axial position determination and optional variable-illumination-depth pseudo total internal reflection microscopy

DOEpatents

Fang, Ning; Sun, Wei

2015-04-21

A method, apparatus, and system for improved VA-TIRFM microscopy. The method comprises automatically controlled calibration of one or more laser sources by precise control of presentation of each laser relative a sample for small incremental changes of incident angle over a range of critical TIR angles. The calibration then allows precise scanning of the sample for any of those calibrated angles for higher and more accurate resolution, and better reconstruction of the scans for super resolution reconstruction of the sample. Optionally the system can be controlled for incident angles of the excitation laser at sub-critical angles for pseudo TIRFM. Optionally both above-critical angle and sub critical angle measurements can be accomplished with the same system.

Mathematical Construction of Magic Squares Utilizing Base-N Arithmetic

ERIC Educational Resources Information Center

O'Brien, Thomas D.

2006-01-01

Magic squares have been of interest as a source of recreation for over 4,500 years. A magic square consists of a square array of n[squared] positive and distinct integers arranged so that the sum of any column, row, or main diagonal is the same. In particular, an array of consecutive integers from 1 to n[squared] forming an nxn magic square is…

Magical ideation -- defense mechanism or neuropathology? A study with multiple sclerosis patients.

PubMed

te Wildt, Bert Theodor; Schultz-Venrath, Ulrich

2004-01-01

The major psychological stress factor in multiple sclerosis (MS) is loss of control of life. In MS patients with impaired cognition, magical ideation might be a characteristic way of thinking. Proof for this may be the high frequency of alternative treatments used by individuals with MS. The study investigates whether the level of magical ideation in MS patients is higher compared to healthy control subjects and, in case of positive confirmation, with which somatic and psychological features it is associated. Moreover, it is aimed to discuss the modalities of magical ideation in general. A German version of the Magical Ideation Scale was validated with a group of 69 healthy subjects. Ninety-four MS patients were additionally assessed with the Dissociative Experience Scale, the Symptom-Check-List-90-Revised and 5 neuropsychological tests. The Magical Ideation Scale did not reveal a significant difference between MS patients and healthy controls (p = 0.968). Among the MS patients, magical ideation shows a correlation neither with age nor with disability, but a positive correlation (p = 0.007; r = 0.329) with the grade of neuropsychological deficiency. Among the psychological parameters, the highest positive correlation with magical ideation was found in dissociation (p = 0.000; r = 0.520). Magical ideation, sharing common features with dissociation, can be viewed as an early defense mechanism when perceiving a loss of control of life, particularly in early stages of MS. In late stages, when developing neuropsychological deficits, it may occur as a substitute for cognitive coping. The data may encourage clinicians to identify magical ideation. In young and previously diagnosed patients, it is important to acknowledge helplessness and support a rather rational way of coping. Training cognitive skills could be crucial to prevent older patients from losing touch with reality. More generally, the occurrence of a significant amount of magical ideation is discussed both as a psychological and a neurophysiologic regression of thinking. Copyright 2004 S. Karger AG, Basel

Children's and adults' reactions to magical and ordinary suggestion: are suggestibility and magical thinking psychologically close relatives?

PubMed

Subbotsky, Eugene

2007-11-01

In Experiment 1, 6- and 9-year-old children and adults were asked to imagine various types of objects. The experimenter then attempted to change the image of those objects in participants' minds by either suggesting that the objects may change against the participants' will, or by asking participants to change the objects as a favor to the experimenter. Two types of suggestive causation were employed: Magical-suggestion (a magic spell was cast with the aim of changing the imagined objects) and ordinary-suggestion (participants were told that the objects in their minds could alter against their will). Ordinary-suggestion was as effective as magical-suggestion in changing the participants' imagined objects. For adults, a direct request for compliance produced a stronger effect than did magical suggestion. This effect was not found in children. In Experiment 2, the two types of suggestion were tested on an alternative type of imagined objects. Adult participants were asked to imagine their futures. It was then proposed that (a) a magic spell could be cast on their futures with the aim of changing them either for the worse or for the better (magical-suggestion), or (b) changing a numerical pattern on a computer screen could change their futures (ordinary-suggestion). All participants denied that changing a numerical pattern on a computer screen could affect their lives, yet in their actions they demonstrated an element of belief in this possibility. As in Experiment 1, in Experiment 2 ordinary suggestion was as effective as magical suggestion. The hypothesis of an historic contiguity between magical causality and ordinary suggestion is discussed.

A Note on Magic Squares

ERIC Educational Resources Information Center

Williams, Horace E.

1974-01-01

A method for generating 3x3 magic squares is developed. A series of questions relating to these magic squares is posed. An invesitgation using matrix methods is suggested with some questions for consideration. (LS)

The Versatile Magic Square.

ERIC Educational Resources Information Center

Watson, Gale A.

2003-01-01

Demonstrates the transformations that are possible to construct a variety of magic squares, including modifications to challenge students from elementary grades through algebra. Presents an example of using magic squares with students who have special needs. (YDS)

Differential network analysis reveals the genome-wide landscape of estrogen receptor modulation in hormonal cancers

PubMed Central

Hsiao, Tzu-Hung; Chiu, Yu-Chiao; Hsu, Pei-Yin; Lu, Tzu-Pin; Lai, Liang-Chuan; Tsai, Mong-Hsun; Huang, Tim H.-M.; Chuang, Eric Y.; Chen, Yidong

2016-01-01

Several mutual information (MI)-based algorithms have been developed to identify dynamic gene-gene and function-function interactions governed by key modulators (genes, proteins, etc.). Due to intensive computation, however, these methods rely heavily on prior knowledge and are limited in genome-wide analysis. We present the modulated gene/gene set interaction (MAGIC) analysis to systematically identify genome-wide modulation of interaction networks. Based on a novel statistical test employing conjugate Fisher transformations of correlation coefficients, MAGIC features fast computation and adaption to variations of clinical cohorts. In simulated datasets MAGIC achieved greatly improved computation efficiency and overall superior performance than the MI-based method. We applied MAGIC to construct the estrogen receptor (ER) modulated gene and gene set (representing biological function) interaction networks in breast cancer. Several novel interaction hubs and functional interactions were discovered. ER+ dependent interaction between TGFβ and NFκB was further shown to be associated with patient survival. The findings were verified in independent datasets. Using MAGIC, we also assessed the essential roles of ER modulation in another hormonal cancer, ovarian cancer. Overall, MAGIC is a systematic framework for comprehensively identifying and constructing the modulated interaction networks in a whole-genome landscape. MATLAB implementation of MAGIC is available for academic uses at https://github.com/chiuyc/MAGIC. PMID:26972162

Is {sup 276}U a doubly magic nucleus?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liliani, N., E-mail: netta.liliani@gmail.com; Sulaksono, A.

2016-04-19

We investigate a possible new doubly magic heavy nucleus by using a relativistic mean-field (RMF) model with the addition of a cross interaction term of omega-rho mesons and an electromagnetic exchange term. We propose that {sup 276}U is a doubly magic nucleus. The evidence for {sup 276}U being a doubly magic nucleus is shown through the two-nucleon gaps, the single-particle energies, and the neutron skin thickness of the nucleus. We have also found that the prediction of {sup 276}U as a doubly magic nucleus by the RMF model is not affected by the inclusion of isoscalar-isovector and electromagnetic exchange couplings.

Bound states for magic state distillation in fault-tolerant quantum computation.

PubMed

Campbell, Earl T; Browne, Dan E

2010-01-22

Magic state distillation is an important primitive in fault-tolerant quantum computation. The magic states are pure nonstabilizer states which can be distilled from certain mixed nonstabilizer states via Clifford group operations alone. Because of the Gottesman-Knill theorem, mixtures of Pauli eigenstates are not expected to be magic state distillable, but it has been an open question whether all mixed states outside this set may be distilled. In this Letter we show that, when resources are finitely limited, nondistillable states exist outside the stabilizer octahedron. In analogy with the bound entangled states, which arise in entanglement theory, we call such states bound states for magic state distillation.

The magic words: Using computers to uncover mental associations for use in magic trick design

PubMed Central

2017-01-01

The use of computational systems to aid in the design of magic tricks has been previously explored. Here further steps are taken in this direction, introducing the use of computer technology as a natural language data sourcing and processing tool for magic trick design purposes. Crowd sourcing of psychological concepts is investigated; further, the role of human associative memory and its exploitation in magical effects is explored. A new trick is developed and evaluated: a physical card trick partially designed by a computational system configured to search for and explore conceptual spaces readily understood by spectators. PMID:28792941

Three-dimensional super-resolved live cell imaging through polarized multi-angle TIRF.

PubMed

Zheng, Cheng; Zhao, Guangyuan; Liu, Wenjie; Chen, Youhua; Zhang, Zhimin; Jin, Luhong; Xu, Yingke; Kuang, Cuifang; Liu, Xu

2018-04-01

Measuring three-dimensional nanoscale cellular structures is challenging, especially when the structure is dynamic. Owing to the informative total internal reflection fluorescence (TIRF) imaging under varied illumination angles, multi-angle (MA) TIRF has been examined to offer a nanoscale axial and a subsecond temporal resolution. However, conventional MA-TIRF still performs badly in lateral resolution and fails to characterize the depth image in densely distributed regions. Here, we emphasize the lateral super-resolution in the MA-TIRF, exampled by simply introducing polarization modulation into the illumination procedure. Equipped with a sparsity and accelerated proximal algorithm, we examine a more precise 3D sample structure compared with previous methods, enabling live cell imaging with a temporal resolution of 2 s and recovering high-resolution mitochondria fission and fusion processes. We also shared the recovery program, which is the first open-source recovery code for MA-TIRF, to the best of our knowledge.

Magic Physics?

ERIC Educational Resources Information Center

Featonby, David

2010-01-01

This article examines several readily available "magic tricks" which base their "trickery" on physics principles, and questions the use of the word "magic" in the 21st century, both in popular children's science and in everyday language. (Contains 18 figures.)

Contact angle distribution of particles at fluid interfaces.

PubMed

Snoeyink, Craig; Barman, Sourav; Christopher, Gordon F

2015-01-27

Recent measurements have implied a distribution of interfacially adsorbed particles' contact angles; however, it has been impossible to measure statistically significant numbers for these contact angles noninvasively in situ. Using a new microscopy method that allows nanometer-scale resolution of particle's 3D positions on an interface, we have measured the contact angles for thousands of latex particles at an oil/water interface. Furthermore, these measurements are dynamic, allowing the observation of the particle contact angle with high temporal resolution, resulting in hundreds of thousands of individual contact angle measurements. The contact angle has been found to fit a normal distribution with a standard deviation of 19.3°, which is much larger than previously recorded. Furthermore, the technique used allows the effect of measurement error, constrained interfacial diffusion, and particle property variation on the contact angle distribution to be individually evaluated. Because of the ability to measure the contact angle noninvasively, the results provide previously unobtainable, unique data on the dynamics and distribution of the adsorbed particles' contact angle.

Magical thinking and memory: distinctiveness effect for tv commercials with magical content.

PubMed

Subbotsky, Eugene; Mathews, Jayne

2011-10-01

The aim of this study was to examine whether memorizing advertised products of television advertisements with magical effects (i.e., talking animals, inanimate objects which turn into humans, objects that appear from thin air or instantly turn into other objects) is easier than memorizing products of advertisements without such effects, by testing immediate and delayed retention. Adolescents and adults viewed two films containing television advertisements and were asked to recall and recognize the films' characters, events, and advertised products. Film 1 included magical effects, but Film 2 did not. On a free-recall test, no differences in the number of items recalled were noted for the two films. On the immediate recognition test, adolescents, but not adults, showed significantly better recognition for the magical than the nonmagical film. When this test was repeated two weeks later, results were reversed: adults, but not adolescents, recognized a significantly larger number of items from the magical film than the nonmagical one. These results are interpreted to accentuate the role of magical thinking in cognitive processes.

The sandwich technique for repair of pectus carinatum and excavatum/carinatum complex.

PubMed

Park, Hyung Joo; Kim, Kyung Soo

2016-09-01

Simple external compression of pectus carinatum seems to have its limitations, particularly the repair of asymmetric pectus carinatum or excavatum/carinatum complex. We devised the sandwich technique (press-molding) to remodel the entire chest wall. The purpose of this study is to introduce the sandwich technique and appraise the early results. Between January 2007 and January 2016, 523 consecutive patients with pectus carinatum and its variants were analyzed retrospectively. No patients were excluded during the study period. The sandwich 1 and 2 techniques using the internal and external pectus bars were for pectus carinatum repair. Modified techniques using the external string and the internal bar were to treat the lower costal flare (the flare-buster) and focal protuberances (the magic string) in pectus excavatum repair. Statistical analyses were carried out using paired and unpaired t -test or Wilcoxon signed rank tests. The sandwich repair with the external and internal bars was applied to 58 pectus carinatum patients: seven symmetric (12.1%), 14 asymmetric (24.1%), and 37 carinatum-excavatum complex (63.8%). After pectus excavatum repair, 426 patients had the flare-buster and 39 patients received the magic string. The sandwich 1 technique achieved near-complete resolution of carinatum in 52 patients (86.2%). The sandwich 2 technique accomplished almost symmetric configuration with no residual carinatum in all six cases. The sandwich technique using the external and internal bars seems to be effective in treating asymmetric pectus carinatum and complex excavatum/carinatum deformities. The flare-buster and the magic string effectively relieve the costal flare and focal protuberances in pectus excavatum repair.

Aerosol Optical Depth Retrievals from High-Resolution Commercial Satellite Imagery Over Areas of High Surface Reflectance

DTIC Science & Technology

2006-06-01

angle Imaging SpectroRadiometer MODIS Moderate Resolution Imaging Spectroradiometer NGA National Geospatial Intelligence Agency POI Principles of...and µ , the cosine of the viewing zenith angle and the effect of the variation of each of these variables on total optical depth. Extraterrestrial ...Eq. (34). Additionally, solar zenith angle also plays a role in the third term on the RHS of Eq. (34) by modifying extraterrestrial spectral solar

MAGIC Computer Simulation. Volume 2: Analyst Manual, Part 1

DTIC Science & Technology

1971-05-01

A review of the subject Magic Computer Simulation User and Analyst Manuals has been conducted based upon a request received from the US Army...1971 4. TITLE AND SUBTITLE MAGIC Computer Simulation Analyst Manual Part 1 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...14. ABSTRACT The MAGIC computer simulation generates target description data consisting of item-by-item listings of the target’s components and air

NTRFACE for MAGIC

DTIC Science & Technology

1989-07-31

40. NO NO ACCESSION NO N7 ?I TITLE (inWijuod Security Claisification) NTRFACE FOR MAGIC 𔃼 PERSONAL AUTHOR(S) N.T. GLADD PE OF REPORT T b TIME...the MAGIC Particle-in-Cell Simulation Code. 19 ABSTRACT (Contianue on reverse if nceary and d ntiy by block number) The NTRFACE system was developed...made concret by applying it to a specific application- a mature, highly complex plasma physics particle in cell simulation code name MAGIC . This

Evaluation of magical thinking: validation of the Illusory Beliefs Inventory.

PubMed

Shihata, Sarah; Egan, Sarah J; Rees, Clare S

2014-01-01

Magical thinking has been related to obsessive-compulsive disorder; yet, little research has examined this construct in other anxiety disorders. The Illusory Beliefs Inventory (IBI) is a recently developed measure of magical thinking. The aim of this study was to investigate the psychometric properties of this new measure and to determine if magical thinking accounts for pathological worry beyond the well-researched constructs of intolerance of uncertainty (IU) and perfectionism. A sample of 502 participants completed an online survey. Confirmatory factor analysis identified a three-factor solution for the IBI, and the measure had good internal consistency (α = .92), test-retest reliability (r = .94) and discriminant validity. Magical thinking, IU, and perfectionism all predicted pathological worry; however, magical thinking accounted for less than 1% of unique variance in worry, suggesting that it is not strongly related to worry. Further investigation regarding the validity and clinical utility of the IBI is required.

Physical aging in graphite/epoxy composites

NASA Technical Reports Server (NTRS)

Kong, E. S. W.

1983-01-01

Sub-Tg annealing has been found to affect the properties of graphite/epoxy composites. The network epoxy studied was based on the chemistry of tetraglycidyl 4,4'-diamino-diphenyl methane (TGDDM) crosslinked by 4,4'-diamino-diphenyl sulfone (DDS). Differential scanning calorimetry, thermal mechanical analysis, and solid-state cross-polarized magic-angle-spinning nuclear magnetic resonance spectroscopy have been utilized in order to characterize this process of recovery towards thermodynamic equilibrium. The volume and enthalpy recovery as well as the 'thermoreversibility' aspects of the physical aging are discussed. This nonequilibrium and time-dependent behavior of network epoxies are considered in view of the increasingly wide applications of TGDDM-DDS epoxies as matrix materials of structural composites in the aerospace industry.

The Influence of Chemical Modification on Linker Rotational Dynamics in Metal-Organic Frameworks.

PubMed

Damron, Joshua T; Ma, Jialiu; Kurz, Ricardo; Saalwächter, Kay; Matzger, Adam J; Ramamoorthy, Ayyalusamy

2018-05-21

The robust synthetic flexibility of metal-organic frameworks (MOFs) offers a promising class of tailorable materials, for which the ability to tune specific physicochemical properties is highly desired. This is achievable only through a thorough description of the consequences for chemical manipulations both in structure and dynamics. Magic angle spinning solid-state NMR spectroscopy offers many modalities in this pursuit, particularly for dynamic studies. Herein, we employ a separated-local-field NMR approach to show how specific intraframework chemical modifications to MOF UiO-66 heavily modulate the dynamic evolution of the organic ring moiety over several orders of magnitude. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hierarchical SAPO‐34 Architectures with Tailored Acid Sites using Sustainable Sugar Templates

PubMed Central

Miletto, Ivana; Ivaldi, Chiara; Paul, Geo; Chapman, Stephanie; Marchese, Leonardo; Raja, Robert

2018-01-01

Abstract In a distinct, bottom‐up synthetic methodology, monosaccharides (fructose and glucose) and disaccharides (sucrose) have been used as mesoporogens to template hierarchical SAPO‐34 catalysts. Detailed materials characterization, which includes solid‐state magic angle spinning NMR and probe‐based FTIR, reveals that, although the mesopore dimensions are modified by the identity of the sugar template, the desirable acid characteristics of the microporous framework are retained. When the activity of the hierarchical SAPO‐34 catalysts was evaluated in the industrially relevant Beckmann rearrangement, under liquid‐phase conditions, the enhanced mass‐transport properties of sucrose‐templated hierarchical SAPO‐34 were found to deliver a superior yield of ϵ‐caprolactam. PMID:29686961

Broadband MAS NMR spectroscopy in the low-power limit

NASA Astrophysics Data System (ADS)

Sanders, Kevin J.; Pell, Andrew J.; Wegner, Sebastian; Grey, Clare P.; Pintacuda, Guido

2018-04-01

We investigate the performance of broadband adiabatic inversion pulses in the high-power (short high-powered adiabatic pulse, SHAP) and low-power (single-sideband-selective adiabatic pulse, S3AP) RF regimes on a spin system subjected to large anisotropic interactions. We show by combined experimental results and spin dynamics simulations that when the magic-angle spinning rate exceeds 100 kHz S3APs begin outperforming SHAPs. This is especially true for low-gamma nuclei, such as 6 Li in paramagnetic Li-ion battery materials. Finally, we show how S3APs can be improved by combining multiple waveforms sweeping over multiple sidebands simultaneously, in order to produce inverted sideband profiles free from intensity biasing.

Solid-state NMR studies of theophylline co-crystals with dicarboxylic acids.

PubMed

Pindelska, Edyta; Sokal, Agnieszka; Szeleszczuk, Lukasz; Pisklak, Dariusz Maciej; Kolodziejski, Waclaw

2014-11-01

In this work, three polycrystalline materials containing co-crystals of theophylline with malonic, maleic, and glutaric acids were studied using (13)C, (15)N and (1)H solid-state NMR and FT-IR spectroscopy. The NMR assignments were supported by gauge including projector augmented waves (GIPAW) calculations of chemical shielding, performed using X-ray determined geometry. The experimental (13)C cross polarization/magic angle spinning (CP/MAS) NMR results and the calculated isotropic chemical shifts were in excellent agreement. A rapid and convenient method for theophylline co-crystals crystal structure analysis has been proposed for co-crystals, which are potentially new APIs. Copyright © 2014 Elsevier B.V. All rights reserved.

Quadrupolar magic angle spinning NMR spectra fitted using the Pearson IV function.

PubMed

Mironenko, Roman M; Belskaya, Olga B; Talsi, Valentin P; Likholobov, Vladimir A

2014-01-01

The Pearson IV function was used to fit the asymmetric solid-state (27)Al NMR spectra of alumina based catalysts. A high convergence (correlation coefficient is no less than 0.997) between experimental and simulated spectra was achieved. The decomposition of the (27)Al NMR spectra of zinc/aluminum mixed oxides with different Zn/Al molar ratio revealed an increased fraction (6-9%) of pentacoordinated aluminum atoms in these oxides as compared to γ-Al2O3. As the Zn/Al ratio is raised, the fraction of [AlO6] octahedral units decreases, while the fraction of [AlO4] tetrahedra increases. Copyright © 2014 Elsevier Inc. All rights reserved.

Solid-state NMR studies of form I of atorvastatin calcium.

PubMed

Wang, Wei David; Gao, Xudong; Strohmeier, Mark; Wang, Wei; Bai, Shi; Dybowski, Cecil

2012-03-22

Solid-state (13)C, (19)F, and (15)N magic angle spinning NMR studies of Form I of atorvastatin calcium are reported, including chemical shift tensors of all resolvable carbon sites and fluorine sites. The complete (13)C and (19)F chemical shift assignments are given based on an extensive analysis of (13)C-(1)H HETCOR and (13)C-(19)F HETCOR results. The solid-state NMR data indicate that the asymmetric unit of this material contains two atorvastatin molecules. A possible structure of Form I of atorvastatin calcium (ATC-I), derived from solid-state NMR data and density functional theory calculations of various structures, is proposed for this important active pharmaceutical ingredient (API).

NMR of samples containing metal foils.

PubMed

Xiong, J; Lock, H; Tao, T; Keeler, C; Maciel, G E

1999-07-01

By using spool configurations of a sample containing aluminum foil, in which the axis of the spool is collinear with the RF coil axis, one can obtain high-quality 13C NMR spectra of static samples of organic material attached to the aluminum foil. By combining such a spool configuration (or, alternatively, analogous samples containing equivalent amounts of fine aluminum powder) with the magic-angle hopping (MAH) technique, one can achieve a high degree of isotropic averaging of the 13C spectrum. This opens to NMR techniques the study of a variety of samples containing macroscopic pieces of metal foils, e.g., thin films deposited on metal foils and electrochemical systems with species adsorbed on metal-foil electrodes.

Met-Activating Genetically Improved Chimeric Factor-1 Promotes Angiogenesis and Hypertrophy in Adult Myogenesis.

PubMed

Ronzoni, Flavio; Ceccarelli, Gabriele; Perini, Ilaria; Benedetti, Laura; Galli, Daniela; Mulas, Francesca; Balli, Martina; Magenes, Giovanni; Bellazzi, Riccardo; De Angelis, Gabriella C; Sampaolesi, Maurilio

2017-01-01

Myogenic progenitor cells (activated satellite cells) are able to express both HGF and its receptor cMet. After muscle injury, HGF-Met stimulation promotes activation and primary division of satellite cells. MAGIC-F1 (Met-Activating Genetically Improved Chimeric Factor-1) is an engineered protein that contains two human Met-binding domains that promotes muscle hypertrophy. MAGIC-F1 protects myogenic precursors against apoptosis and increases their fusion ability enhancing muscle differentiation. Hemizygous and homozygous Magic-F1 transgenic mice displayed constitutive muscle hypertrophy. Here we describe microarray analysis on Magic-F1 myogenic progenitor cells showing an altered gene signatures on muscular hypertrophy and angiogenesis compared to wild-type cells. In addition, we performed a functional analysis on Magic-F1+/+ transgenic mice versus controls using treadmill test. We demonstrated that Magic-F1+/+ mice display an increase in muscle mass and cross-sectional area leading to an improvement in running performance. Moreover, the presence of MAGIC-F1 affected positively the vascular network, increasing the vessel number in fast twitch fibers. Finally, the gene expression profile analysis of Magic-F1+/+ satellite cells evidenced transcriptomic changes in genes involved in the control of muscle growth, development and vascularisation. We showed that MAGIC-F1-induced muscle hypertrophy affects positively vascular network, increasing vessel number in fast twitch fibers. This was due to unique features of mammalian skeletal muscle and its remarkable ability to adapt promptly to different physiological demands by modulating the gene expression profile in myogenic progenitors. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Finding All Solutions to the Magic Hexagram

ERIC Educational Resources Information Center

Holland, Jason; Karabegov, Alexander

2008-01-01

In this article, a systematic approach is given for solving a magic star puzzle that usually is accomplished by trial and error or "brute force." A connection is made to the symmetries of a cube, thus the name Magic Hexahedron.

MAGIC Computer Simulation. Volume 1: User Manual

DTIC Science & Technology

1970-07-01

vulnerability and MAGIC programs. A three-digit code is assigned to each component of the target, such as armor, gun tube; and a two-digit code is assigned to...A review of the subject Magic Computer Simulation User and Analyst Manuals has been conducted based upon a request received from the US Army...1970 4. TITLE AND SUBTITLE MAGIC Computer Simulation 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT

An Overview of the MAGIC Project

DTIC Science & Technology

1993-12-01

unlimnitedj_ _______ 13. ABSTRACT (Mxmwn WO0 words) This note provides an overview of the MAGIC project1 which is developing a high-speed, wide-area...298Rv.9 16. PRICE COASSDE 3.1 17. SEURITY18. SEURITY19. SEURITY2930.2BIA NO An Overview of the M 93B0000173 MAGIC Project December 1993 Barbara B...Intelligence Division ii ABSTRACT This note provides an overview of the MAGIC project, which is developing a high-speed, wide- area networking testbed

Secrets of the Chinese magic mirror replica

NASA Astrophysics Data System (ADS)

Mak, Se-yuen; Yip, Din-yan

2001-03-01

We examine the structure of five Chinese magic mirror replicas using a special imaging technique developed by the authors. All mirrors are found to have a two-layered structure. The reflecting surface that gives rise to a projected magic pattern on the screen is hidden under a polished half-reflecting top layer. An alternative method of making the magic mirror using ancient technology has been proposed. Finally, we suggest a simple method of reconstructing a mirror replica in the laboratory.

An fMRI investigation of expectation violation in magic tricks.

PubMed

Danek, Amory H; Öllinger, Michael; Fraps, Thomas; Grothe, Benedikt; Flanagin, Virginia L

2015-01-01

Magic tricks violate the expected causal relationships that form an implicit belief system about what is possible in the world around us. Observing a magic effect seemingly invalidates our implicit assumptions about what action causes which outcome. We aimed at identifying the neural correlates of such expectation violations by contrasting 24 video clips of magic tricks with 24 control clips in which the expected action-outcome relationship is upheld. Using fMRI, we measured the brain activity of 25 normal volunteers while they watched the clips in the scanner. Additionally, we measured the professional magician who had performed the magic tricks under the assumption that, in contrast to naïve observers, the magician himself would not perceive his own magic tricks as an expectation violation. As the main effect of magic - control clips in the normal sample, we found higher activity for magic in the head of the caudate nucleus (CN) bilaterally, the left inferior frontal gyrus and the left anterior insula. As expected, the magician's brain activity substantially differed from these results, with mainly parietal areas (supramarginal gyrus bilaterally) activated, supporting our hypothesis that he did not experience any expectation violation. These findings are in accordance with previous research that has implicated the head of the CN in processing changes in the contingency between action and outcome, even in the absence of reward or feedback.

Magic in the machine: a computational magician's assistant.

PubMed

Williams, Howard; McOwan, Peter W

2014-01-01

A human magician blends science, psychology, and performance to create a magical effect. In this paper we explore what can be achieved when that human intelligence is replaced or assisted by machine intelligence. Magical effects are all in some form based on hidden mathematical, scientific, or psychological principles; often the parameters controlling these underpinning techniques are hard for a magician to blend to maximize the magical effect required. The complexity is often caused by interacting and often conflicting physical and psychological constraints that need to be optimally balanced. Normally this tuning is done by trial and error, combined with human intuitions. Here we focus on applying Artificial Intelligence methods to the creation and optimization of magic tricks exploiting mathematical principles. We use experimentally derived data about particular perceptual and cognitive features, combined with a model of the underlying mathematical process to provide a psychologically valid metric to allow optimization of magical impact. In the paper we introduce our optimization methodology and describe how it can be flexibly applied to a range of different types of mathematics based tricks. We also provide two case studies as exemplars of the methodology at work: a magical jigsaw, and a mind reading card trick effect. We evaluate each trick created through testing in laboratory and public performances, and further demonstrate the real world efficacy of our approach for professional performers through sales of the tricks in a reputable magic shop in London.

Migration to Current Open Source Technologies by MagIC Enables a More Responsive Website, Quicker Development Times, and Increased Community Engagement

NASA Astrophysics Data System (ADS)

Jarboe, N.; Minnett, R.; Koppers, A.; Constable, C.; Tauxe, L.; Jonestrask, L.

2017-12-01

The Magnetics Information Consortium (MagIC) supports an online database for the paleo, geo, and rock magnetic communities ( https://earthref.org/MagIC ). Researchers can upload data into the archive and download data as selected with a sophisticated search system. MagIC has completed the transition from an Oracle backed, Perl based, server oriented website to an ElasticSearch backed, Meteor based thick client website technology stack. Using JavaScript on both the sever and the client enables increased code reuse and allows easy offloading many computational operations to the client for faster response. On-the-fly data validation, column header suggestion, and spreadsheet online editing are some new features available with the new system. The 3.0 data model, method codes, and vocabulary lists can be browsed via the MagIC website and more easily updated. Source code for MagIC is publicly available on GitHub ( https://github.com/earthref/MagIC ). The MagIC file format is natively compatible with the PmagPy ( https://github.com/PmagPy/PmagPy) paleomagnetic analysis software. MagIC files can now be downloaded from the database and viewed and interpreted in the PmagPy GUI based tool, pmag_gui. Changes or interpretations of the data can then be saved by pmag_gui in the MagIC 3.0 data format and easily uploaded to the MagIC database. The rate of new contributions to the database has been increasing with many labs contributing measurement level data for the first time in the last year. Over a dozen file format conversion scripts are available for translating non-MagIC measurement data files into the MagIC format for easy uploading. We will continue to work with more labs until the whole community has a manageable workflow for contributing their measurement level data. MagIC will continue to provide a global repository for archiving and retrieving paleomagnetic and rock magnetic data and, with the new system in place, be able to more quickly respond to the community's requests for changes and improvements.

A Simple Parameterization of 3 x 3 Magic Squares

ERIC Educational Resources Information Center

Trenkler, Gotz; Schmidt, Karsten; Trenkler, Dietrich

2012-01-01

In this article a new parameterization of magic squares of order three is presented. This parameterization permits an easy computation of their inverses, eigenvalues, eigenvectors and adjoints. Some attention is paid to the Luoshu, one of the oldest magic squares.

MISR Level 2 TOA/Cloud Classifier parameters (MIL2TCCL_V2)

NASA Technical Reports Server (NTRS)

Diner, David J. (Principal Investigator)

The TOA/Cloud Classifiers contain the Angular Signature Cloud Mask (ASCM), a scene classifier calculated using support vector machine technology (SVM) both of which are on a 1.1 km grid, and cloud fractions at 17.6 km resolution that are available in different height bins (low, middle, high) and are also calculated on an angle-by-angle basis. [Location=GLOBAL] [Temporal_Coverage: Start_Date=2000-02-24; Stop_Date=] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Latitude_Resolution=17.6 km; Longitude_Resolution=17.6 km; Horizontal_Resolution_Range=10 km - < 50 km or approximately .09 degree - < .5 degree; Temporal_Resolution=about 15 orbits/day; Temporal_Resolution_Range=Daily - < Weekly, Daily - < Weekly].

Effect of science magic applied in interactive lecture demonstrations on conceptual understanding

NASA Astrophysics Data System (ADS)

Taufiq, Muhammad; Suhandi, Andi; Liliawati, Winny

2017-08-01

Research about the application of science magic-assisting Interactive Lecture Demonstrations (ILD) has been conducted. This research is aimed at providing description about the comparison of the improvement of the conceptual understanding of lesson on pressure between students who receive physics lesson through science magic-assisting ILD and students who receive physics lesson through ILD without science magic. This research used a quasi-experiment methods with Control Group Pretest-Posttest Design. The subject of the research is all students of class VIII in one of MTs (Islamic junior high school) in Pekalongan. Research samples were selected using random sampling technique. Data about students' conceptual understanding was collected using test instrument of conceptual understanding in the form of multiple choices. N-gain average calculation was performed in order to determine the improvement of students' conceptual understanding. The result of the research shows that conceptual understanding of students on lesson about pressure who received lesson with ILD using science magic <0.44> is higher than students who received lesson with ILD without science magic <0.25>. Therefore, the conclusion is that the application of science magic ILD is more effective to improve the conceptual understanding of lesson on pressure.

The role of magical thinking in hallucinations. Comparisons of clinical and non-clinical groups.

PubMed

García-Montes, José M; Pérez-Álvarez, Marino; Odriozola-González, Paula; Vallina-Fernández, Oscar; Perona-Garcelán, Salvador

2014-11-01

Magical thinking consists of accepting the possibility that events that, according to the causal concepts of a culture, cannot have any causal relationship, but might somehow nevertheless have one. Magical thinking has been related to both obsessive-compulsive disorder and schizophrenia. The purpose of this study was to investigate the role of magical thinking in hallucinations of patients diagnosed with schizophrenia. Four groups were recruited for this purpose from a clinical population (hallucinating schizophrenic patients, patients diagnosed with psychoses who had never hallucinated, obsessive-compulsive disorder patients and a clinical control group) and a non-clinical control group, who were given the Magical Ideation Scale. The results show that magical ideation differentiates the group of schizophrenic patients with auditory hallucinations from the rest of the groups that participated in the design. Items related to "mind reading", to the presence of auditory illusions in response to sound stimuli, and to the sense of sometimes being accompanied by an evil presence are the most closely related to the presence of auditory hallucinations. Magical thinking, understood as beliefs in non-consensual modes of causation, is closely linked to auditory hallucinations in patients diagnosed with schizophrenia.

Solid state NMR: The essential technology for helical membrane protein structural characterization

PubMed Central

Cross, Timothy A.; Ekanayake, Vindana; Paulino, Joana; Wright, Anna

2014-01-01

NMR spectroscopy of helical membrane proteins has been very challenging on multiple fronts. The expression and purification of these proteins while maintaining functionality has consumed countless graduate student hours. Sample preparations have depended on whether solution or solid-state NMR spectroscopy was to be performed – neither have been easy. In recent years it has become increasingly apparent that membrane mimic environments influence the structural result. Indeed, in these recent years we have rediscovered that Nobel laureate, Christian Anfinsen, did not say that protein structure was exclusively dictated by the amino acid sequence, but rather by the sequence in a given environment (Anfinsen, 1973) [106]. The environment matters, molecular interactions with the membrane environment are significant and many examples of distorted, non-native membrane protein structures have recently been documented in the literature. However, solid-state NMR structures of helical membrane proteins in proteoliposomes and bilayers are proving to be native structures that permit a high resolution characterization of their functional states. Indeed, solid-state NMR is uniquely able to characterize helical membrane protein structures in lipid environments without detergents. Recent progress in expression, purification, reconstitution, sample preparation and in the solid-state NMR spectroscopy of both oriented samples and magic angle spinning samples has demonstrated that helical membrane protein structures can be achieved in a timely fashion. Indeed, this is a spectacular opportunity for the NMR community to have a major impact on biomedical research through the solid-state NMR spectroscopy of these proteins. PMID:24412099

Solid state NMR: The essential technology for helical membrane protein structural characterization

NASA Astrophysics Data System (ADS)

Cross, Timothy A.; Ekanayake, Vindana; Paulino, Joana; Wright, Anna

2014-02-01

NMR spectroscopy of helical membrane proteins has been very challenging on multiple fronts. The expression and purification of these proteins while maintaining functionality has consumed countless graduate student hours. Sample preparations have depended on whether solution or solid-state NMR spectroscopy was to be performed - neither have been easy. In recent years it has become increasingly apparent that membrane mimic environments influence the structural result. Indeed, in these recent years we have rediscovered that Nobel laureate, Christian Anfinsen, did not say that protein structure was exclusively dictated by the amino acid sequence, but rather by the sequence in a given environment (Anfinsen, 1973) [106]. The environment matters, molecular interactions with the membrane environment are significant and many examples of distorted, non-native membrane protein structures have recently been documented in the literature. However, solid-state NMR structures of helical membrane proteins in proteoliposomes and bilayers are proving to be native structures that permit a high resolution characterization of their functional states. Indeed, solid-state NMR is uniquely able to characterize helical membrane protein structures in lipid environments without detergents. Recent progress in expression, purification, reconstitution, sample preparation and in the solid-state NMR spectroscopy of both oriented samples and magic angle spinning samples has demonstrated that helical membrane protein structures can be achieved in a timely fashion. Indeed, this is a spectacular opportunity for the NMR community to have a major impact on biomedical research through the solid-state NMR spectroscopy of these proteins.

Nuclear magnetic resonance spectroscopy reveals metabolic changes in living cardiomyocytes after low doses of ionizing radiation.

PubMed

Gramatyka, Michalina; Skorupa, Agnieszka; Sokół, Maria

2018-01-01

Several lines of evidence indicate that exposure of heart to ionizing radiation increases the risk of cardiotoxicity manifested by heart dysfunction and cardiovascular diseases. It was initially believed that the heart is an organ relatively resistant to radiation. Currently, however, it is suspected that even low doses of radiation (< 2 Gy) may have a negative impact on the cardiovascular system. Cardiotoxicity of ionizing radiation is associated with metabolic changes observed in cardiac cells injured by radiation. In this study, we used human cardiomyocytes as a model system, and studied their metabolic response to radiation using high-resolution magic angle spinning nuclear magnetic resonance techniques (HR-MAS NMR). Human cardiomyocytes cultured in vitro were exposed to ionizing radiation and their survival was assessed by clonogenic assay. Changes in apoptosis intensity and cell cycle distribution after the irradiation were measured as well. NMR spectra of cardiomyocytes were acquired using Bruker Avance 400 MHz spectrometer at a spinning rate of 3200 Hz. Survival of cardiomyocytes after NMR experiments was assessed by the Trypan blue exclusion assay. Exposure of cardiomyocytes to small doses of ionizing radiation had no effect on cell proliferation potential and intensity of cell death. However, analysis of metabolic profiles revealed changes in lipids, threonine, glycine, glycerophosphocholine, choline, valine, isoleucine, glutamate, reduced glutathione and taurine metabolism. The results of this study showed that ionizing radiation affects metabolic profiles of cardiomyocytes even at low doses, which potentially have no effect on cell viability.

MRS study of meningeal hemangiopericytoma and edema: a comparison with meningothelial meningioma.

PubMed

Righi, Valeria; Tugnoli, Vitaliano; Mucci, Adele; Bacci, Antonella; Bonora, Sergio; Schenetti, Luisa

2012-10-01

Intracranial hemangiopericytomas (HPCs) are rare tumors and their radiological appearance resembles that of meningiomas, especially meningothelial meningiomas. To increase the knowledge on the biochemical composition of this type of tumor for better diagnosis and prognosis, we performed a molecular study using ex vivo high resolution magic angle spinning (HR-MAS) magnetic resonance spectroscopy (MRS) perfomed on HPC and peritumoral edematous tissues. Moreover, to help in the discrimination between HPC and meningothelial meningioma we compared the ex vivo HR-MAS spectra of samples from one patient with HPC and 5 patients affected by meningothelial meningioma. Magnetic resonance imaging (MRI), in vivo localized single voxel 1H-MRS was also performed on the same patients prior to surgery and the in vivo and ex vivo MRS spectra were compared. We observed the presence of OH-butyrate, together with glucose in HPC and a low amount of N-acetylaspartate in the edema, that may reflect neuronal alteration responsible for associated epilepsy. Many differences between HPC and meningothelial meningioma were identified. The relative ratios of myo-inositol, glucose and gluthatione with respect to glutamate are higher in HPC compared to meningioma; whereas the relative ratios of creatine, glutamine, alanine, glycine and choline-containing compounds with respect to glutamate are lower in HPC compared to meningioma. These data will be useful to improve the interpretation of in vivo MRS spectra resulting in a more accurate diagnosis of these rare tumors.

Rhodopsin-lipid interactions studied by NMR.

PubMed

Soubias, Olivier; Gawrisch, Klaus

2013-01-01

The biophysical properties of the lipid matrix are known to influence function of integral membrane proteins. We report on a sample preparation method for reconstitution of membrane proteins which uses porous anodic aluminum oxide (AAO) filters with 200-nm-wide pores of high density. The substrate permits formation of tubular, single membranes that line the inner surface of pores. One square centimeter of filter with a thickness of 60μm yields on the order of 500cm(2) of solid-supported single bilayer surface, sufficient for NMR studies. The tubular bilayers are free of detergent, fully hydrated, and accessible for ligands from one side of the membrane. The use of AAO filters greatly improves reproducibility of the reconstitution process such that the influence of protein on lipid order parameters can be studied with high resolution. As an example, results for the G protein-coupled receptor of class A, bovine rhodopsin, are shown. By (2)H NMR order parameter measurements, it is detected that rhodopsin insertion elastically deforms membranes near the protein. Furthermore, by (1)H saturation-transfer NMR under conditions of magic angle spinning, we demonstrate detection of preferences in interactions of rhodopsin with particular lipid species. It is assumed that function of integral membrane proteins depends on both protein-induced elastic deformations of the lipid matrix and preferences for interaction of the protein with particular lipid species in the first layer of lipids surrounding the protein. Copyright © 2013 Elsevier Inc. All rights reserved.

Neuroglial metabolic compartmentation underlying leptin deficiency in the obese ob/ob mice as detected by magnetic resonance imaging and spectroscopy methods

PubMed Central

Delgado, Teresa C; Violante, Inês R; Nieto-Charques, Laura; Cerdán, Sebastián

2011-01-01

Manganese-Enhanced Magnetic Resonance Imaging (MEMRI), 1H and 13C High-Resolution-Magic Angle Spinning (HR-MAS) Spectroscopy, and genomic approaches were used to compare cerebral activation and neuronal and glial oxidative metabolism in ad libitum fed C57BL6/J leptin-deficient, genetically obese ob/ob mice. T1-weighted Magnetic Resonance Images across the hypothalamic Arcuate and the Ventromedial nuclei were acquired kinetically after manganese infusion. Neuroglial compartmentation was investigated in hypothalamic biopsies after intraperitoneal injections of [1-13C]glucose or [2-13C]acetate. Total RNA was extracted to determine the effects of leptin deficiency in the expression of representative genes coding for regulatory enzymes of hypothalamic energy pathways and glutamatergic neurotransmission. Manganese-Enhanced Magnetic Resonance Imaging revealed enhanced cerebral activation in the hypothalamic Arcuate and Ventromedial nuclei of the ob/ob mice. 13C HR-MAS analysis showed increased 13C accumulation in the hypothalamic glutamate and glutamine carbons of ob/ob mice after the administration of [1-13C]glucose, a primarily neuronal substrate. Hypothalamic expression of the genes coding for glucokinase, phosphofructokinase, pyruvate dehydrogenase, and glutamine synthase was not significantly altered while pyruvate kinase expression was slightly upregulated. In conclusion, leptin deficiency associated with obesity led to increased cerebral activation in the hypothalamic Arcuate and Ventromedial nuclei, concomitant with significant increases in neuronal oxidative metabolism and glutamatergic neurotransmission. PMID:21971349

Metabolic profiles of triple-negative and luminal A breast cancer subtypes in African-American identify key metabolic differences.

PubMed

Tayyari, Fariba; Gowda, G A Nagana; Olopade, Olufunmilayo F; Berg, Richard; Yang, Howard H; Lee, Maxwell P; Ngwa, Wilfred F; Mittal, Suresh K; Raftery, Daniel; Mohammed, Sulma I

2018-02-20

Breast cancer, a heterogeneous disease with variable pathophysiology and biology, is classified into four major subtypes. While hormonal- and antibody-targeted therapies are effective in the patients with luminal and HER-2 subtypes, the patients with triple-negative breast cancer (TNBC) subtype do not benefit from these therapies. The incidence rates of TNBC subtype are higher in African-American women, and the evidence indicates that these women have worse prognosis compared to women of European descent. The reasons for this disparity remain unclear but are often attributed to TNBC biology. In this study, we performed metabolic analysis of breast tissues to identify how TNBC differs from luminal A breast cancer (LABC) subtypes within the African-American and Caucasian breast cancer patients, respectively. We used High-Resolution Magic Angle Spinning (HR-MAS) 1H Nuclear magnetic resonance (NMR) to perform the metabolomic analysis of breast cancer and adjacent normal tissues (total n=82 samples). TNBC and LABC subtypes in African American women exhibited different metabolic profiles. Metabolic profiles of these subtypes were also distinct from those revealed in Caucasian women. TNBC in African-American women expressed higher levels of glutathione, choline, and glutamine as well as profound metabolic alterations characterized by decreased mitochondrial respiration and increased glycolysis concomitant with decreased levels of ATP. TNBC in Caucasian women was associated with increased pyrimidine synthesis. These metabolic alterations could potentially be exploited as novel treatment targets for TNBC.

Metabolic profiles of triple-negative and luminal A breast cancer subtypes in African-American identify key metabolic differences

PubMed Central

Tayyari, Fariba; Gowda, G.A. Nagana; Olopade, Olufunmilayo F.; Berg, Richard; Yang, Howard H.; Lee, Maxwell P.; Ngwa, Wilfred F.; Mittal, Suresh K.; Raftery, Daniel; Mohammed, Sulma I.

2018-01-01

Breast cancer, a heterogeneous disease with variable pathophysiology and biology, is classified into four major subtypes. While hormonal- and antibody-targeted therapies are effective in the patients with luminal and HER-2 subtypes, the patients with triple-negative breast cancer (TNBC) subtype do not benefit from these therapies. The incidence rates of TNBC subtype are higher in African-American women, and the evidence indicates that these women have worse prognosis compared to women of European descent. The reasons for this disparity remain unclear but are often attributed to TNBC biology. In this study, we performed metabolic analysis of breast tissues to identify how TNBC differs from luminal A breast cancer (LABC) subtypes within the African-American and Caucasian breast cancer patients, respectively. We used High-Resolution Magic Angle Spinning (HR-MAS) 1H Nuclear magnetic resonance (NMR) to perform the metabolomic analysis of breast cancer and adjacent normal tissues (total n=82 samples). TNBC and LABC subtypes in African American women exhibited different metabolic profiles. Metabolic profiles of these subtypes were also distinct from those revealed in Caucasian women. TNBC in African-American women expressed higher levels of glutathione, choline, and glutamine as well as profound metabolic alterations characterized by decreased mitochondrial respiration and increased glycolysis concomitant with decreased levels of ATP. TNBC in Caucasian women was associated with increased pyrimidine synthesis. These metabolic alterations could potentially be exploited as novel treatment targets for TNBC. PMID:29545929

Alterations of choline phospholipid metabolism in endometrial cancer are caused by choline kinase alpha overexpression and a hyperactivated deacylation pathway.

PubMed

Trousil, Sebastian; Lee, Patrizia; Pinato, David J; Ellis, James K; Dina, Roberto; Aboagye, Eric O; Keun, Hector C; Sharma, Rohini

2014-12-01

Metabolic rearrangements subsequent to malignant transformation are not well characterized in endometrial cancer. Identification of altered metabolites could facilitate imaging-guided diagnosis, treatment surveillance, and help to identify new therapeutic options. Here, we used high-resolution magic angle spinning magnetic resonance mass spectroscopy on endometrial cancer surgical specimens and normal endometrial tissue to investigate the key modulators that might explain metabolic changes, incorporating additional investigations using qRT-PCR, Western blotting, tissue microarrays (TMA), and uptake assays of [(3)H]-labeled choline. Lipid metabolism was severely dysregulated in endometrial cancer with various amino acids, inositols, nucleobases, and glutathione also altered. Among the most important lipid-related alterations were increased phosphocholine levels (increased 70% in endometrial cancer). Mechanistic investigations revealed that changes were not due to altered choline transporter expression, but rather due to increased expression of choline kinase α (CHKA) and an activated deacylation pathway, as indicated by upregulated expression of the catabolic enzymes LYPLA1, LYPLA2, and GPCPD1. We confirmed the significance of CHKA overexpression on a TMA, including a large series of endometrial hyperplasia, atypical hyperplasia, and adenocarcinoma tissues, supporting a role for CHKA in malignant transformation. Finally, we documented several-fold increases in the uptake of [(3)H]choline in endometrial cancer cell lines compared with normal endometrial stromal cells. Our results validate deregulated choline biochemistry as an important source of noninvasive imaging biomarkers for endometrial cancer. ©2014 American Association for Cancer Research.

NMR crystallography of campho[2,3-c]pyrazole (Z' = 6): combining high-resolution 1H-13C solid-state MAS NMR spectroscopy and GIPAW chemical-shift calculations.

PubMed

Webber, Amy L; Emsley, Lyndon; Claramunt, Rosa M; Brown, Steven P

2010-09-30

(1)H-(13)C two-dimensional magic-angle spinning (MAS) solid-state NMR correlation spectra, recorded with the MAS-J-HMQC experiment, are presented for campho[2,3-c]pyrazole. For each (13)C moiety, there are six resonances associated with the six distinct molecules in the asymmetric unit cell (Z' = 6). The one-bond C-H correlations observed in the 2D (1)H-(13)C MAS-J-HMQC spectra allow the experimental determination of the (1)H and (13)C chemical shifts associated with the separate CH, CH(2), and CH(3) groups. (1)H and (13)C chemical shifts calculated by using the GIPAW (Gauge Including Projector Augmented Waves) plane-wave pseudopotential approach are presented. Calculations for the whole unit cell (12 × 29 = 348 atoms, with geometry optimization of all atoms) allow the assignment of the experimental (1)H and (13)C chemical shifts to the six distinct molecules. The calculated chemical shifts for the full crystal structure are compared with those for isolated molecules as extracted from the geometry-optimized crystal structure. In this way, the effect of intermolecular interactions on the observed chemical shifts is quantified. In particular, the calculations are sufficiently precise to differentiate the small (<1 ppm) differences between the (1)H chemical shifts of the six resonances associated with each distinct CH or CH(2) moiety.

Ex vivo metabolic fingerprinting identifies biomarkers predictive of prostate cancer recurrence following radical prostatectomy.

PubMed

Braadland, Peder R; Giskeødegård, Guro; Sandsmark, Elise; Bertilsson, Helena; Euceda, Leslie R; Hansen, Ailin F; Guldvik, Ingrid J; Selnæs, Kirsten M; Grytli, Helene H; Katz, Betina; Svindland, Aud; Bathen, Tone F; Eri, Lars M; Nygård, Ståle; Berge, Viktor; Taskén, Kristin A; Tessem, May-Britt

2017-11-21

Robust biomarkers that identify prostate cancer patients with high risk of recurrence will improve personalised cancer care. In this study, we investigated whether tissue metabolites detectable by high-resolution magic angle spinning magnetic resonance spectroscopy (HR-MAS MRS) were associated with recurrence following radical prostatectomy. We performed a retrospective ex vivo study using HR-MAS MRS on tissue samples from 110 radical prostatectomy specimens obtained from three different Norwegian cohorts collected between 2002 and 2010. At the time of analysis, 50 patients had experienced prostate cancer recurrence. Associations between metabolites, clinicopathological variables, and recurrence-free survival were evaluated using Cox proportional hazards regression modelling, Kaplan-Meier survival analyses and concordance index (C-index). High intratumoural spermine and citrate concentrations were associated with longer recurrence-free survival, whereas high (total-choline+creatine)/spermine (tChoCre/Spm) and higher (total-choline+creatine)/citrate (tChoCre/Cit) ratios were associated with shorter time to recurrence. Spermine concentration and tChoCre/Spm were independently associated with recurrence in multivariate Cox proportional hazards modelling after adjusting for clinically relevant risk factors (C-index: 0.769; HR: 0.72; P=0.016 and C-index: 0.765; HR: 1.43; P=0.014, respectively). Spermine concentration and tChoCre/Spm ratio in prostatectomy specimens were independent prognostic markers of recurrence. These metabolites can be noninvasively measured in vivo and may thus offer predictive value to establish preoperative risk assessment nomograms.

IDH1 R132H mutation generates a distinct phospholipid metabolite profile in glioma.

PubMed

Esmaeili, Morteza; Hamans, Bob C; Navis, Anna C; van Horssen, Remco; Bathen, Tone F; Gribbestad, Ingrid S; Leenders, William P; Heerschap, Arend

2014-09-01

Many patients with glioma harbor specific mutations in the isocitrate dehydrogenase gene IDH1 that associate with a relatively better prognosis. IDH1-mutated tumors produce the oncometabolite 2-hydroxyglutarate. Because IDH1 also regulates several pathways leading to lipid synthesis, we hypothesized that IDH1-mutant tumors have an altered phospholipid metabolite profile that would impinge on tumor pathobiology. To investigate this hypothesis, we performed (31)P-MRS imaging in mouse xenograft models of four human gliomas, one of which harbored the IDH1-R132H mutation. (31)P-MR spectra from the IDH1-mutant tumor displayed a pattern distinct from that of the three IDH1 wild-type tumors, characterized by decreased levels of phosphoethanolamine and increased levels of glycerophosphocholine. This spectral profile was confirmed by ex vivo analysis of tumor extracts, and it was also observed in human surgical biopsies of IDH1-mutated tumors by (31)P high-resolution magic angle spinning spectroscopy. The specificity of this profile for the IDH1-R132H mutation was established by in vitro (31)P-NMR of extracts of cells overexpressing IDH1 or IDH1-R132H. Overall, our results provide evidence that the IDH1-R132H mutation alters phospholipid metabolism in gliomas involving phosphoethanolamine and glycerophosphocholine. These new noninvasive biomarkers can assist in the identification of the mutation and in research toward novel treatments that target aberrant metabolism in IDH1-mutant glioma. ©2014 American Association for Cancer Research.

Early Childhood Corner: Take the Magic Out of Your Classroom!

ERIC Educational Resources Information Center

Andrews, Angela Giglio

1995-01-01

Students are often as mystified by mathematical procedures as they are by magic tricks. This article suggests ways of making the estimation of how many jelly beans in a jar and the 20-questions game less magical and more understandable. (MKR)

Magical thinking by inpatient staff members.

PubMed

Pilette, W L

1983-01-01

Magical thinking is a primitive form of mental activity which, nevertheless, the author contends, is common among mental health professionals. Four examples of magical thinking by inpatient staff members are presented and briefly explored, in order to shed light on our work and ourselves.

[Further Distinctions between Magic, Reality, Religion, and Fiction. Commentaries.

ERIC Educational Resources Information Center

Boyer, Pascal; Taylor, Marjorie; Harris, Paul L.; Chandler, Michael; Johnson, Carl N.

1997-01-01

Contains the following commentaries: "Further Distinctions between Magic, Reality, Religion, and Fiction"; "The Role of Creative Control and Culture in Children's Fantasy/Reality Judgments"; "The Last of the Magicians? Children, Scientists, and the Invocation of Hidden Causal Powers"; "Rescuing Magical Thinking…

The Magic Background of Pearl Harbor. Volume 1 (February 14, 1941 - May 12, 1941)

DTIC Science & Technology

1977-01-01

1977 2. REPORT TYPE 3. DATES COVERED 00-00-1977 to 00-00-1977 4. TITLE AND SUBTITLE The ’ Magic ’ Background of Pearl Harbor. Volume 1: February...34 MAGIC " BACKGROUND OF PEARL HARBOR VOLUME I (February 14, 1941-May 12,1941) /- / DEPARTMENT OF DEFENSE UNITED STATES OF AMERICA For sale by the...The Department of Defense is releasing for public use and research this multi-volume study giving the " MAGIC " or communications intelligence background

Further Studies of the NRL Collective Particle Accelerator VIA Numerical Modeling with the MAGIC Code.

DTIC Science & Technology

1984-08-01

COLLFCTIVF PAPTTCLE ACCELERATOR VIA NUMERICAL MODFLINC WITH THF MAGIC CODE Robert 1. Darker Auqust 19F4 Final Report for Period I April. qI84 - 30...NUMERICAL MODELING WITH THE MAGIC CODE Robert 3. Barker August 1984 Final Report for Period 1 April 1984 - 30 September 1984 Prepared for: Scientific...Collective Final Report Particle Accelerator VIA Numerical Modeling with April 1 - September-30, 1984 MAGIC Code. 6. PERFORMING ORG. REPORT NUMBER MRC/WDC-R

[Magical thinking and self development].

PubMed

Resch, F

1994-01-01

Based on a historical survey of the term "magic thinking" structural aspects of primary process and prelogical thinking will be elucidated. Developmental necessities for the emergence of magic interpretations in children of pre-school age are proposed. The thesis will be formulated, that magic interpretations may help the developing self in the management of life-circumstances during a period of cognitive egocentrism: feelings of non-competence may be compensated, and the locus of control may be held in the face of experiences of inferiority.

MISR Level 2 TOA/Cloud Classifier parameters (MIL2TCCL_V3)

NASA Technical Reports Server (NTRS)

Diner, David J. (Principal Investigator)

The TOA/Cloud Classifiers contain the Angular Signature Cloud Mask (ASCM), a scene classifier calculated using support vector machine technology (SVM) both of which are on a 1.1 km grid, and cloud fractions at 17.6 km resolution that are available in different height bins (low, middle, high) and are also calculated on an angle-by-angle basis. [Temporal_Coverage: Start_Date=2000-02-24; Stop_Date=] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Latitude_Resolution=1.1 km; Longitude_Resolution=1.1 km; Temporal_Resolution=about 15 orbits/day].

[The magic universe of cures: the role of magic practices and witchcraft in the universe of 17th century Mato Grosso].

PubMed

Sá, Mario

2009-01-01

The article analyzes the role of healing agents played by practitioners of magic and witchcraft in Mato Grosso society during the 17th century. It observes that magic and witchcraft were developed as competitors, alternatives or associated with other forms of healing (official and lay). It points out how such roles contributed to the process of subjugating its practitioners, especially Africans, Indians and their descendents, and were appropriated as an opportunity for survival in the colonial slave society. The pastoral visit made by Bruno Pinna in 1785 to Cuiabá and nearby areas served as the principal source of knowledge regarding the practices and practitioners of magic and witchcraft.

When "Holiday Magic" Hurts.

ERIC Educational Resources Information Center

Goldstein, Karen

2001-01-01

Claims that religious messages in public school are not acceptable and are hurtful to kids who do not subscribe to the beliefs expressed in those messages. Describes the author's personal experience in helping a teacher transform the script for "Christmas Magic" into the more inclusive "Holiday Magic." (RS)

[Investigation into the formation of proportions of "realistic thinking vs magical thinking" in paranoid schizophrenia].

PubMed

Jarosz, M; Pankiewicz, Z; Buczek, I; Poprawska, I; Rojek, J; Zaborowski, A

1993-01-01

Both magical thinking among healthy persons and magical and symbolic thinking in schizophrenia were discussed. The investigation covered 100 paranoid schizophrenics. They also underwent an examination in connection with the formation of the remaining 3 proportions. Both "realistic thinking and magical thinking" scales were used. An ability to think realistically was preserved, to a varying degree, in all patients, with 50% of those examined having shown an explicit or very explicit ability to follow realistic thinking. The above findings deviate from a simplified cognitive model within the discussed range. It was further confirmed that realistic thinking may coexist with magical thinking, and, in some cases, it concerns the same events. That type of disorders of the content of thinking are referred to as magical-realistic interpenetration. The results, and particularly high coefficient of negative correlation within the scales of the examined proportions, confirm the correctness of the assumption that the investigated modes of thinking form an antithetic bipolarity of proportions, aggregating antithetic values, therefore being also complementary.

Magical attachment: Children in magical relations with hospital clowns

PubMed Central

2012-01-01

The aim of the present study was to achieve a theoretical understanding of several different-age children's experiences of magic relations with hospital clowns in the context of medical care, and to do so using psychological theory and a child perspective. The method used was qualitative and focused on nine children. The results showed that age was important to consider in better understanding how the children experienced the relation with the hospital clowns, how they described the magical aspects of the encounter and how they viewed the importance of clown encounters to their own well-being. The present theoretical interpretation characterized the encounter with hospital clowns as a magical safe area, an intermediate area between fantasy and reality. The discussion presented a line of reasoning concerning a magical attachment between the child and the hospital clowns, stating that this attachment: a) comprised a temporary relation; b) gave anonymity; c) entailed reversed roles; and d) created an emotional experience of boundary-transcending opportunities. PMID:22371813

The presence of magical thinking in obsessive compulsive disorder.

PubMed

Einstein, Danielle A; Menzies, Ross G

2004-05-01

Two research groups have raised the possibility that magical ideation may be a fundamental feature of obsessive-compulsive disorder. It has been proposed to underlie thought action fusion and superstitious beliefs. In this study, the Magical Ideation scale, the Lucky Behaviours and Lucky Beliefs scales, the Thought Action Fusion-Revised scale, the Padua Inventory, and the Obsessive Compulsive Inventory-Short Version were completed by 60 obsessive compulsive patients at a hospital clinic. Of all the measures, the Magical Ideation (MI) scale was found to be the most strongly related to obsessive compulsive symptoms. Large and significant relationships between MI scores and the measures of OCD were obtained even when alternative constructs (Lucky Behaviours, Lucky Beliefs, Thought Action Fusion-Revised scales) were held constant. No other variable remained significantly related to the Obsessive Compulsive Inventory-Short Version when magical ideation scores were held constant. The findings suggest that a general magical thinking tendency may underpin previous observed links between superstitiousness, thought action fusion and OCD severity.

71Ga-77Se connectivities and proximities in gallium selenide crystal and glass probed by solid-state NMR

NASA Astrophysics Data System (ADS)

Nagashima, Hiroki; Trébosc, Julien; Calvez, Laurent; Pourpoint, Frédérique; Mear, François; Lafon, Olivier; Amoureux, Jean-Paul

2017-09-01

We introduce two-dimensional (2D) 71Ga-77Se through-bond and through-space correlation experiments. Such correlations are achieved using (i) the J-mediated Refocused Insensitive Nuclei Enhanced by Polarization Transfer (J-RINEPT) method with 71Ga excitation and 77Se Carr-Purcell-Meiboon-Gill (CPMG) detection, as well as (ii) the J- or dipolar-mediated Hetero-nuclear Multiple-Quantum Correlation (J- or D-HMQC) schemes with 71Ga excitation and quadrupolar CPMG (QCPMG) detection. These methods are applied to the crystalline β-Ga2Se3 and the 0.2Ga2Se3-0.8GeSe2 glass. Such glass leads to a homogeneous and reproducible glass-ceramic, which is a good alternative to single-crystalline Ge and polycrystalline ZnSe materials for making lenses transparent in the IR range for thermal imaging applications. We show that 2D 71Ga-77Se correlation experiments allow resolving the 77Se signals of molecular units, which are not resolved in the 1D 77Se CPMG spectrum. Additionally, the build-up curves of the J-RINEPT and the J-HMQC experiments allow the estimate of the 71Ga-77Se J-couplings via one and three-bonds in the three-dimensional network of β-Ga2Se3. Furthermore, these build-up curves show that the one-bond 1J71Ga-77Se couplings in the 0.2Ga2Se3-0.8GeSe2 glass are similar to those measured for β-Ga2Se3. We also report 2D 71Ga Satellite Transition Magic-Angle Spinning (STMAS) spectrum of β-Ga2Se3 using QCPMG detection at high magnetic field and high Magic-Angle Spinning frequency using large radio frequency field. Such spectrum allows separating the signal of β-Ga2Se3 and that of an impurity.

Insight into small molecule binding to the neonatal Fc receptor by X-ray crystallography and 100 kHz magic-angle-spinning NMR

PubMed Central

Macpherson, Alex; Smith-Penzel, Susanne; Basse, Nicolas; Lecomte, Fabien; Deboves, Hervé; Taylor, Richard D.; Norman, Tim; Porter, John; Waters, Lorna C.; Westwood, Marta; Cossins, Ben; Cain, Katharine; White, James; Griffin, Robert; Prosser, Christine; Kelm, Sebastian; Sullivan, Amy H.; Fox, David; Carr, Mark D.; Henry, Alistair; Taylor, Richard; Meier, Beat H.; Oschkinat, Hartmut; Lawson, Alastair D.

2018-01-01

Aiming at the design of an allosteric modulator of the neonatal Fc receptor (FcRn)–Immunoglobulin G (IgG) interaction, we developed a new methodology including NMR fragment screening, X-ray crystallography, and magic-angle-spinning (MAS) NMR at 100 kHz after sedimentation, exploiting very fast spinning of the nondeuterated soluble 42 kDa receptor construct to obtain resolved proton-detected 2D and 3D NMR spectra. FcRn plays a crucial role in regulation of IgG and serum albumin catabolism. It is a clinically validated drug target for the treatment of autoimmune diseases caused by pathogenic antibodies via the inhibition of its interaction with IgG. We herein present the discovery of a small molecule that binds into a conserved cavity of the heterodimeric, extracellular domain composed of an α-chain and β2-microglobulin (β2m) (FcRnECD, 373 residues). X-ray crystallography was used alongside NMR at 100 kHz MAS with sedimented soluble protein to explore possibilities for refining the compound as an allosteric modulator. Proton-detected MAS NMR experiments on fully protonated [13C,15N]-labeled FcRnECD yielded ligand-induced chemical-shift perturbations (CSPs) for residues in the binding pocket and allosteric changes close to the interface of the two receptor heterodimers present in the asymmetric unit as well as potentially in the albumin interaction site. X-ray structures with and without ligand suggest the need for an optimized ligand to displace the α-chain with respect to β2m, both of which participate in the FcRnECD–IgG interaction site. Our investigation establishes a method to characterize structurally small molecule binding to nondeuterated large proteins by NMR, even in their glycosylated form, which may prove highly valuable for structure-based drug discovery campaigns. PMID:29782488

Insight into small molecule binding to the neonatal Fc receptor by X-ray crystallography and 100 kHz magic-angle-spinning NMR.

PubMed

Stöppler, Daniel; Macpherson, Alex; Smith-Penzel, Susanne; Basse, Nicolas; Lecomte, Fabien; Deboves, Hervé; Taylor, Richard D; Norman, Tim; Porter, John; Waters, Lorna C; Westwood, Marta; Cossins, Ben; Cain, Katharine; White, James; Griffin, Robert; Prosser, Christine; Kelm, Sebastian; Sullivan, Amy H; Fox, David; Carr, Mark D; Henry, Alistair; Taylor, Richard; Meier, Beat H; Oschkinat, Hartmut; Lawson, Alastair D

2018-05-01

Aiming at the design of an allosteric modulator of the neonatal Fc receptor (FcRn)-Immunoglobulin G (IgG) interaction, we developed a new methodology including NMR fragment screening, X-ray crystallography, and magic-angle-spinning (MAS) NMR at 100 kHz after sedimentation, exploiting very fast spinning of the nondeuterated soluble 42 kDa receptor construct to obtain resolved proton-detected 2D and 3D NMR spectra. FcRn plays a crucial role in regulation of IgG and serum albumin catabolism. It is a clinically validated drug target for the treatment of autoimmune diseases caused by pathogenic antibodies via the inhibition of its interaction with IgG. We herein present the discovery of a small molecule that binds into a conserved cavity of the heterodimeric, extracellular domain composed of an α-chain and β2-microglobulin (β2m) (FcRnECD, 373 residues). X-ray crystallography was used alongside NMR at 100 kHz MAS with sedimented soluble protein to explore possibilities for refining the compound as an allosteric modulator. Proton-detected MAS NMR experiments on fully protonated [13C,15N]-labeled FcRnECD yielded ligand-induced chemical-shift perturbations (CSPs) for residues in the binding pocket and allosteric changes close to the interface of the two receptor heterodimers present in the asymmetric unit as well as potentially in the albumin interaction site. X-ray structures with and without ligand suggest the need for an optimized ligand to displace the α-chain with respect to β2m, both of which participate in the FcRnECD-IgG interaction site. Our investigation establishes a method to characterize structurally small molecule binding to nondeuterated large proteins by NMR, even in their glycosylated form, which may prove highly valuable for structure-based drug discovery campaigns.

Two-Dimensional Micro-/Nanoradian Angle Generator with High Resolution and Repeatability Based on Piezo-Driven Double-Axis Flexure Hinge and Three Capacitive Sensors.

PubMed

Tan, Xinran; Zhu, Fan; Wang, Chao; Yu, Yang; Shi, Jian; Qi, Xue; Yuan, Feng; Tan, Jiubin

2017-11-19

This study presents a two-dimensional micro-/nanoradian angle generator (2D-MNAG) that achieves high angular displacement resolution and repeatability using a piezo-driven flexure hinge for two-dimensional deflections and three capacitive sensors for output angle monitoring and feedback control. The principal error of the capacitive sensor for precision microangle measurement is analyzed and compensated for; so as to achieve a high angle output resolution of 10 nrad (0.002 arcsec) and positioning repeatability of 120 nrad (0.024 arcsec) over a large angular range of ±4363 μrad (±900 arcsec) for the 2D-MNAG. The impact of each error component, together with the synthetic error of the 2D-MNAG after principal error compensation are determined using Monte Carlo simulation for further improvement of the 2D-MNAG.

Two-Dimensional Micro-/Nanoradian Angle Generator with High Resolution and Repeatability Based on Piezo-Driven Double-Axis Flexure Hinge and Three Capacitive Sensors

PubMed Central

Tan, Xinran; Zhu, Fan; Wang, Chao; Yu, Yang; Shi, Jian; Qi, Xue; Yuan, Feng; Tan, Jiubin

2017-01-01

This study presents a two-dimensional micro-/nanoradian angle generator (2D-MNAG) that achieves high angular displacement resolution and repeatability using a piezo-driven flexure hinge for two-dimensional deflections and three capacitive sensors for output angle monitoring and feedback control. The principal error of the capacitive sensor for precision microangle measurement is analyzed and compensated for; so as to achieve a high angle output resolution of 10 nrad (0.002 arcsec) and positioning repeatability of 120 nrad (0.024 arcsec) over a large angular range of ±4363 μrad (±900 arcsec) for the 2D-MNAG. The impact of each error component, together with the synthetic error of the 2D-MNAG after principal error compensation are determined using Monte Carlo simulation for further improvement of the 2D-MNAG. PMID:29156595

Magic in the machine: a computational magician's assistant

PubMed Central

Williams, Howard; McOwan, Peter W.

2014-01-01

A human magician blends science, psychology, and performance to create a magical effect. In this paper we explore what can be achieved when that human intelligence is replaced or assisted by machine intelligence. Magical effects are all in some form based on hidden mathematical, scientific, or psychological principles; often the parameters controlling these underpinning techniques are hard for a magician to blend to maximize the magical effect required. The complexity is often caused by interacting and often conflicting physical and psychological constraints that need to be optimally balanced. Normally this tuning is done by trial and error, combined with human intuitions. Here we focus on applying Artificial Intelligence methods to the creation and optimization of magic tricks exploiting mathematical principles. We use experimentally derived data about particular perceptual and cognitive features, combined with a model of the underlying mathematical process to provide a psychologically valid metric to allow optimization of magical impact. In the paper we introduce our optimization methodology and describe how it can be flexibly applied to a range of different types of mathematics based tricks. We also provide two case studies as exemplars of the methodology at work: a magical jigsaw, and a mind reading card trick effect. We evaluate each trick created through testing in laboratory and public performances, and further demonstrate the real world efficacy of our approach for professional performers through sales of the tricks in a reputable magic shop in London. PMID:25452736

A high-sensitivity search for extraterrestrial intelligence at lambda 18 cm

NASA Technical Reports Server (NTRS)

Tarter, J.; Cuzzi, J.; Black, D.; Clark, T.

1980-01-01

A targeted high-sensitivity search for narrow-band signals near a wavelength of 18 cm has been conducted using the 91-m radiotelescope of the National Radio Astronomy Observatory. The search included 201 nearby solar-type stars and achieved a frequency resolution of 5.5 Hz over a 1.4-MHz bandwidth. This high spectral resolution was obtained through a non-real-time reduction procedure using a Mark I VLBI recording terminal in conjunction with the CDC 7600 computational facility at the NASA-Ames Research Center. This is the first high-resolution search for narrow-band signals in this wavelength regime. To date it is the most sensitive search per unit observing time of any search strategy which does not postulate a unique magic frequency. Data show no evidence for narrow-band signals due to extraterrestrial intelligence at a 12-standard-deviation upper limit on signal strength of 1.1 x 10 to the -23rd W/sq m.

Ultranarrowband searches for extraterrestrial intelligence with dedicated signal-processing hardware.

PubMed

Horowitz, P; Matthews, B S; Forster, J; Linscott, I; Teague, C C; Chen, K; Backus, P

1986-01-01

Multichannel spectroscopy with millihertz resolution constitutes an attractive strategy for a microwave search for extraterrestrial intelligence (SETI), assuming the transmission of a narrow-band radiofrequency beacon. Such resolution matches the properties of the interstellar medium, and the necessary receiver Doppler corrections provide a high degree of interference rejection. We have constructed a frequency-agile swept receiver with an 8,388,608-channel spectrum analyzer, on-line signal recognition, and multithreshold archiving. A search of 250 Sun-like stars at 1.4 and 2.8 GHz has been carried out with the Arecibo 305-m antenna, and a meridian transit search of the northern sky is in progress at the Harvard-Smithsonian 26-m antenna. Successive spectra of 400 kHz at 0.05 Hz resolution are searched for features characteristic of an intentional narrowband beacon transmission. These spectra are centered on guessable ("magic") frequencies (such as the 21-cm hydrogen hyperfine line), referenced successively to the local standard of rest, the galactic barycenter, and the cosmic blackbody rest frame.

Structural changes in C–S–H gel during dissolution: Small-angle neutron scattering and Si-NMR characterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trapote-Barreira, Ana, E-mail: anatrapotebarreira@gmail.com; Porcar, Lionel; Large Scale Structure Group, Institut Laue Langevin, Grenoble

2015-06-15

Flow-through experiments were conducted to study the calcium–silicate–hydrate (C–S–H) gel dissolution kinetics. During C–S–H gel dissolution the initial aqueous Ca/Si ratio decreases to reach the stoichiometric value of the Ca/Si ratio of a tobermorite-like phase (Ca/Si = 0.83). As the Ca/Si ratio decreases, the solid C–S–H dissolution rate increases from (4.5 × 10{sup −} {sup 14} to 6.7 × 10{sup −} {sup 12}) mol m{sup −} {sup 2} s{sup −} {sup 1}. The changes in the microstructure of the dissolving C–S–H gel were characterized by small-angle neutron scattering (SANS) and {sup 29}Si magic-angle-spinning nuclear magnetic resonance ({sup 29}Si-MAS NMR). Themore » SANS data were fitted using a fractal model. The SANS specific surface area tends to increase with time and the obtained fit parameters reflect the changes in the nanostructure of the dissolving solid C–S–H within the gel. The {sup 29}Si MAS NMR analyses show that with dissolution the solid C–S–H structure tends to a more ordered tobermorite structure, in agreement with the Ca/Si ratio evolution.« less

Chinese "Magic" Mirrors.

ERIC Educational Resources Information Center

Swinson, Derek B.

1992-01-01

Chinese "magic" mirrors are made from bronze with the front side a mirror and the reverse side a molded image. When light is reflected from the mirror,the image on the reverse side appears. Discusses reflections of conventional mirrors, possible explanations for the magic mirror phenomenon, and applications of the phenomenon to…

U.S. EPA, Pesticide Product Label, FLEAGO THE MAGIC CRYSTAL, 07/09/1997

EPA Pesticide Factsheets

2011-04-21

... Fleago The Magic Crystal '~~~:ul~~i~;~i~~!;~i~~fat~~I~~n~w~~~~: W~?~:~iA~~~~~r~Y '~~;: ... lhe Magic Crystal ...

High-resolution inverse synthetic aperture radar imaging for large rotation angle targets based on segmented processing algorithm

NASA Astrophysics Data System (ADS)

Chen, Hao; Zhang, Xinggan; Bai, Yechao; Tang, Lan

2017-01-01

In inverse synthetic aperture radar (ISAR) imaging, the migration through resolution cells (MTRCs) will occur when the rotation angle of the moving target is large, thereby degrading image resolution. To solve this problem, an ISAR imaging method based on segmented preprocessing is proposed. In this method, the echoes of large rotating target are divided into several small segments, and every segment can generate a low-resolution image without MTRCs. Then, each low-resolution image is rotated back to the original position. After image registration and phase compensation, a high-resolution image can be obtained. Simulation and real experiments show that the proposed algorithm can deal with the radar system with different range and cross-range resolutions and significantly compensate the MTRCs.

"You Will": Technology, Magic, and the Cultural Contexts of Technical Communication.

ERIC Educational Resources Information Center

Kitalong, Karla Saari

2000-01-01

Provides some background on the use of magical language in technical contexts, gives examples of magical discourse in technology advertisements and newsmagazine articles, and proposes a technical communication pedagogy of media analysis. Notes that the proposed pedagogy involves students conducting diagnostic critiques of media texts and affords…

Magical Landscapes: Two Love Stories.

ERIC Educational Resources Information Center

Moore, John Noell

2002-01-01

Introduces two books about magic, one a collection of essays "Ex Libris: Confessions of a Common Reader," which describes the author's inherited lifelong passion for books and reading; and the other a novel, "Mangos, Bananas and Coconuts: A Cuban Love Story," which tells a story of love and magic that seems both real and…

Magical Mysteries. Texas Reading Club, 1984. A Librarian's Planning Handbook.

ERIC Educational Resources Information Center

Oliver, Jim

Designed to encourage library use by Texas youth, the Texas Reading Club programs usually include a structured reading program and a variety of entertaining literature-related storyhours, puppet shows, films, and other attractive happenings. This handbook for the 1984 theme--"magical mysteries"--focuses on mysteries, magic, and adventure…

Redefining the magic square on numerical characters

NASA Astrophysics Data System (ADS)

Nasution, M. K. M.; Sawaluddin

2018-02-01

As a number system, the magic square is different from the others. Characteristic depends not only on size but also depends on numerical character in computation. This paper has redefined the term of magic square formally, by exposing the inductive general characteristics of cases to numerical ordering of numbers.

Magic User’s Manual 2006

DTIC Science & Technology

2006-12-01

K (M) M issioin Research MRC/WDC-R-556 MAGIC USER’S MANUAL 2006 Author(s): Larry Ludeking ATK Mission Research Contract No.: F49620-03-C-0030 L¾[iJiD... Magic Tool Suite for Windows. It uses the standard Windows Help so it is pretty self-explanatory. You can use the panel to the left to scan through... MAGIC Go to Part 2. MCL Commands Go to Part 3. Tirnc and Space Go to Part 4. Spatial Extensions Go to Part 5. Properties Go to Part 6. Algorithms Go

A Compact Low-loss Magic-T using Microstrip-Slotline Transitions

NASA Technical Reports Server (NTRS)

U-yen, Kongpop; Wollack, Edward J.; Moseley, Samuel H.; Papapolymerou, John; Laskar, Joy

2007-01-01

The design of a compact low-loss magic-T is proposed. The planar magic-T incorporates the compact microstrip-slotline tee junction and small microstrip-slotline transition area to reduce slotline radiation. The experimental results show that the magic-T produces broadband in-phase and out-of-phase power combiner/divider responses, has an average in-band insertion loss of 0.3 dB and small in-band phase and amplitude imbalance of less than plus or minus 1.6 deg. and plus or minus 0.3 dB, respectively.

Lenz's Law Magic Trick

NASA Astrophysics Data System (ADS)

Ruiz, Michael J.

2006-02-01

The demonstration of Lenz's law by dropping a powerful magnet down a nonmagnetic metal pipe has become a classic lecture-hall demonstration.1,2 An inexpensive version is packaged as a professional magic trick3 called "Newton's Nightmare." Combining sleight-of-hand with a demonstration of Lenz's law is a surefire way to heighten student interest. The subsequent student discussion motivated by a desire to understand the magic trick can lead to a memorable physics lesson. This paper will discuss Lenz's law magic and review literature that reveals the subtlety of the physics.

The use of magical plants by curanderos in the Ecuador highlands

PubMed Central

Cavender, Anthony P; Albán, Manuel

2009-01-01

Although the use of plants for treating supernaturally caused illnesses (e.g., soul loss, evil wind, witchcraft) has been documented in the Ecuador highlands, so-called magical plants have received much less focused attention than plants used for treating naturalistic disorders. Drawing on interviews done in 2002 and 2003 with 116 curanderos residing in the Ecuador highlands, this paper examines the characteristics of plants identified as magical, how they are used, and how the study of magical plants provides insights into the mindscape of residents of the highlands. PMID:19161618

Modernizing the MagIC Paleomagnetic and Rock Magnetic Database Technology Stack to Encourage Code Reuse and Reproducible Science

NASA Astrophysics Data System (ADS)

Minnett, R.; Koppers, A. A. P.; Jarboe, N.; Jonestrask, L.; Tauxe, L.; Constable, C.

2016-12-01

The Magnetics Information Consortium (https://earthref.org/MagIC/) develops and maintains a database and web application for supporting the paleo-, geo-, and rock magnetic scientific community. Historically, this objective has been met with an Oracle database and a Perl web application at the San Diego Supercomputer Center (SDSC). The Oracle Enterprise Cluster at SDSC, however, was decommissioned in July of 2016 and the cost for MagIC to continue using Oracle became prohibitive. This provided MagIC with a unique opportunity to reexamine the entire technology stack and data model. MagIC has developed an open-source web application using the Meteor (http://meteor.com) framework and a MongoDB database. The simplicity of the open-source full-stack framework that Meteor provides has improved MagIC's development pace and the increased flexibility of the data schema in MongoDB encouraged the reorganization of the MagIC Data Model. As a result of incorporating actively developed open-source projects into the technology stack, MagIC has benefited from their vibrant software development communities. This has translated into a more modern web application that has significantly improved the user experience for the paleo-, geo-, and rock magnetic scientific community.

Do cultural factors affect causal beliefs? Rational and magical thinking in Britain and Mexico.

PubMed

Subbotsky, Eugene; Quinteros, Graciela

2002-11-01

In two experiments, unusual phenomena (spontaneous destruction of objects in an empty wooden box) were demonstrated to adult participants living in rural communities in Mexico. These were accompanied by actions which had no physical link to the destroyed object but could suggest either scientifically based (the effect of an unknown physical device) or non-scientifically based (the effect of a 'magic spell') causal explanations of the event. The results were compared to the results of the matching two experiments from the earlier study made in Britain. The expectation that scientifically based explanations would prevail in British participants' judgments and behaviours, whereas Mexican participants would be more tolerant toward magical explanations, received only partial support. The prevalence of scientific explanations over magical explanations was evident in British participants' verbal judgments but not in Mexican participants' judgments. In their behavioural responses under the low-risk condition, British participants rejected magical explanations more frequently than did Mexican participants. However, when the risk of disregarding the possible causal effect of magic was increased, participants in both samples showed an equal degree of credulity in the possible effect of magic. The data are interpreted in terms of the relationships between scientific and 'folk' representations of causality and object permanence.

Managing Rock and Paleomagnetic Data Flow with the MagIC Database: from Measurement and Analysis to Comprehensive Archive and Visualization

NASA Astrophysics Data System (ADS)

Koppers, A. A.; Minnett, R. C.; Tauxe, L.; Constable, C.; Donadini, F.

2008-12-01

The Magnetics Information Consortium (MagIC) is commissioned to implement and maintain an online portal to a relational database populated by rock and paleomagnetic data. The goal of MagIC is to archive all measurements and derived properties for studies of paleomagnetic directions (inclination, declination) and intensities, and for rock magnetic experiments (hysteresis, remanence, susceptibility, anisotropy). Organizing data for presentation in peer-reviewed publications or for ingestion into databases is a time-consuming task, and to facilitate these activities, three tightly integrated tools have been developed: MagIC-PY, the MagIC Console Software, and the MagIC Online Database. A suite of Python scripts is available to help users port their data into the MagIC data format. They allow the user to add important metadata, perform basic interpretations, and average results at the specimen, sample and site levels. These scripts have been validated for use as Open Source software under the UNIX, Linux, PC and Macintosh© operating systems. We have also developed the MagIC Console Software program to assist in collating rock and paleomagnetic data for upload to the MagIC database. The program runs in Microsoft Excel© on both Macintosh© computers and PCs. It performs routine consistency checks on data entries, and assists users in preparing data for uploading into the online MagIC database. The MagIC website is hosted under EarthRef.org at http://earthref.org/MAGIC/ and has two search nodes, one for paleomagnetism and one for rock magnetism. Both nodes provide query building based on location, reference, methods applied, material type and geological age, as well as a visual FlashMap interface to browse and select locations. Users can also browse the database by data type (inclination, intensity, VGP, hysteresis, susceptibility) or by data compilation to view all contributions associated with previous databases, such as PINT, GMPDB or TAFI or other user-defined compilations. Query results are displayed in a digestible tabular format allowing the user to descend from locations to sites, samples, specimens and measurements. At each stage, the result set can be saved and, when supported by the data, can be visualized by plotting global location maps, equal area, XY, age, and depth plots, or typical Zijderveld, hysteresis, magnetization and remanence diagrams.

Rates and Mechanisms of Oil Shale Pyrolysis: A Chemical Structure Approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fletcher, Thomas; Pugmire, Ronald

2015-01-01

Three pristine Utah Green River oil shale samples were obtained and used for analysis by the combined research groups at the University of Utah and Brigham Young University. Oil shale samples were first demineralized and the separated kerogen and extracted bitumen samples were then studied by a host of techniques including high resolution liquid-state carbon-13 NMR, solid-state magic angle sample spinning 13C NMR, GC/MS, FTIR, and pyrolysis. Bitumen was extracted from the shale using methanol/dichloromethane and analyzed using high resolution 13C NMR liquid state spectroscopy, showing carbon aromaticities of 7 to 11%. The three parent shales and the demineralized kerogensmore » were each analyzed with solid-state 13C NMR spectroscopy. Carbon aromaticity of the kerogen was 23-24%, with 10-12 aromatic carbons per cluster. Crushed samples of Green River oil shale and its kerogen extract were pyrolyzed at heating rates from 1 to 10 K/min at pressures of 1 and 40 bar and temperatures up to 1000°C. The transient pyrolysis data were fit with a first-order model and a Distributed Activation Energy Model (DAEM). The demineralized kerogen was pyrolyzed at 10 K/min in nitrogen at atmospheric pressure at temperatures up to 525°C, and the pyrolysis products (light gas, tar, and char) were analyzed using 13C NMR, GC/MS, and FTIR. Details of the kerogen pyrolysis have been modeled by a modified version of the chemical percolation devolatilization (CPD) model that has been widely used to model coal combustion/pyrolysis. This refined CPD model has been successful in predicting the char, tar, and gas yields of the three shale samples during pyrolysis. This set of experiments and associated modeling represents the most sophisticated and complete analysis available for a given set of oil shale samples.« less

Water Deficit and Salinity Stress Reveal Many Specific QTL for Plant Growth and Fruit Quality Traits in Tomato

PubMed Central

Diouf, Isidore A.; Derivot, Laurent; Bitton, Frédérique; Pascual, Laura; Causse, Mathilde

2018-01-01

Quality is a key trait in plant breeding, especially for fruit and vegetables. Quality involves several polygenic components, often influenced by environmental conditions with variable levels of genotype × environment interaction that must be considered in breeding strategies aiming to improve quality. In order to assess the impact of water deficit and salinity on tomato fruit quality, we evaluated a multi-parent advanced generation intercross (MAGIC) tomato population in contrasted environmental conditions over 2 years, one year in control vs. drought condition and the other in control vs. salt condition. Overall 250 individual lines from the MAGIC population—derived from eight parental lines covering a large diversity in cultivated tomato—were used to identify QTL in both experiments for fruit quality and yield component traits (fruit weight, number of fruit, Soluble Solid Content, firmness), phenology traits (time to flower and ripe) and a vegetative trait, leaf length. All the traits showed a large genotype variation (33–86% of total phenotypic variation) in both experiments and high heritability whatever the year or treatment. Significant genotype × treatment interactions were detected for five of the seven traits over the 2 years of experiments. QTL were mapped using 1,345 SNP markers. A total of 54 QTL were found among which 15 revealed genotype × environment interactions and 65% (35 QTL) were treatment specific. Confidence intervals of the QTL were projected on the genome physical map and allowed identifying regions carrying QTL co-localizations, suggesting pleiotropic regulation. We then applied a strategy for candidate gene detection based on the high resolution mapping offered by the MAGIC population, the allelic effect of each parental line at the QTL and the sequence information of the eight parental lines. PMID:29559986

The sandwich technique for repair of pectus carinatum and excavatum/carinatum complex

PubMed Central

Kim, Kyung Soo

2016-01-01

Background Simple external compression of pectus carinatum seems to have its limitations, particularly the repair of asymmetric pectus carinatum or excavatum/carinatum complex. We devised the sandwich technique (press-molding) to remodel the entire chest wall. The purpose of this study is to introduce the sandwich technique and appraise the early results. Methods Between January 2007 and January 2016, 523 consecutive patients with pectus carinatum and its variants were analyzed retrospectively. No patients were excluded during the study period. The sandwich 1 and 2 techniques using the internal and external pectus bars were for pectus carinatum repair. Modified techniques using the external string and the internal bar were to treat the lower costal flare (the flare-buster) and focal protuberances (the magic string) in pectus excavatum repair. Statistical analyses were carried out using paired and unpaired t-test or Wilcoxon signed rank tests. Results The sandwich repair with the external and internal bars was applied to 58 pectus carinatum patients: seven symmetric (12.1%), 14 asymmetric (24.1%), and 37 carinatum-excavatum complex (63.8%). After pectus excavatum repair, 426 patients had the flare-buster and 39 patients received the magic string. The sandwich 1 technique achieved near-complete resolution of carinatum in 52 patients (86.2%). The sandwich 2 technique accomplished almost symmetric configuration with no residual carinatum in all six cases. Conclusions The sandwich technique using the external and internal bars seems to be effective in treating asymmetric pectus carinatum and complex excavatum/carinatum deformities. The flare-buster and the magic string effectively relieve the costal flare and focal protuberances in pectus excavatum repair. PMID:27747176

Simultaneous piston position and tilt angle sensing for large vertical displacement micromirrors by frequency detection inductive sensing

NASA Astrophysics Data System (ADS)

Tseng, V. F.-G.; Xie, H.

2015-11-01

This paper presents a frequency detection based inductive eddy current sensing mechanism to simultaneously sense the piston position and tilt angle of the mirror plate of large vertical displacement micromirrors that exhibit piston scan ranges above 100 μm. This is accomplished by sensing the inductance change, and thus resonant frequency shift, of two microfabricated sensing coils packaged underneath the mirror plate. For demonstration purpose, the coils were paired with discrete circuit components to oscillate at 11.9 MHz and 12.5 MHz, respectively. The piston position and tilt angle of the mirror plate could be simultaneously monitored over a 500 μm piston scan range, achieving a maximum piston sensitivity of 4.15 kHz/μm with a piston sensing resolution of 96 nm and a maximum tilt angle sensitivity of 60.5 kHz/° with a tilt angle sensing resolution of 0.0013°. Analytical modeling of the coil inductance change via image theory was also conducted, showing that the sensor sensitivity and resolution could be improved by increasing the coil oscillation frequency and decreasing the coil size.

Sensitivity enhancements in MQ-MAS NMR of spin-5/2 nuclei using modulated rf mixing pulses

NASA Astrophysics Data System (ADS)

Vosegaard, Thomas; Massiot, Dominique; Grandinetti, Philip J.

2000-08-01

An X- overlineX pulse train with stepped modulation frequency was employed to enhance the multiple-quantum to single-quantum coherence transfer in the mixing period of the multiple-quantum magic-angle spinning (MQ-MAS) experiment for spin I=5/2 nuclei. Two MQ-MAS pulse sequences employing this mixing scheme for the triple-to-single and quintuple-to-single quantum coherence transfers have been designed and their performance is demonstrated for 27Al on samples of NaSi 3AlO 8 and 9Al 2O 3·2B 2O 3 . Compared to the standard single-pulse mixing sequences, the sensitivity is approximately doubled in the present experiments.

Structural Changes Associated with Transthyretin Misfolding and Amyloid Formation Revealed by Solution and Solid-State NMR

DOE PAGES

Lim, Kwang Hun; Dasari, Anvesh K. R.; Hung, Ivan; ...

2016-03-21

Elucidation of structural changes involved in protein misfolding and amyloid formation is crucial for unraveling the molecular basis of amyloid formation. We report structural analyses of the amyloidogenic intermediate and amyloid aggregates of transthyretin using solution and solid-state nuclear magnetic resonance (NMR) spectroscopy. These NMR solution results show that one of the two main β-sheet structures (CBEF β-sheet) is maintained in the aggregation-competent intermediate, while the other DAGH β-sheet is more flexible on millisecond time scales. Magic-angle-spinning solid-state NMR revealed that AB loop regions interacting with strand A in the DAGH β-sheet undergo conformational changes, leading to the destabilized DAGHmore » β-sheet.« less

Monitoring Cocrystal Formation via In Situ Solid-State NMR.

PubMed

Mandala, Venkata S; Loewus, Sarel J; Mehta, Manish A

2014-10-02

A detailed understanding of the mechanism of organic cocrystal formation remains elusive. Techniques that interrogate a reacting system in situ are preferred, though experimentally challenging. We report here the results of a solid-state in situ NMR study of the spontaneous formation of a cocrystal between a pharmaceutical mimic (caffeine) and a coformer (malonic acid). Using (13)C magic angle spinning NMR, we show that the formation of the cocrystal may be tracked in real time. We find no direct evidence for a short-lived, chemical shift-resolved amorphous solid intermediate. However, changes in the line width and line center of the malonic acid methylene resonance, in the course of the reaction, provide subtle clues to the mode of mass transfer that underlies cocrystal formation.

Observation of shape isomers states in fission fragments

NASA Astrophysics Data System (ADS)

Kamanin, D. V.; Pyatkov, Yu V.; Alexandrov, A. A.; Alexandrova, I. A.; Mkaza, N.; Malaza, V.; Kuznetsova, E. A.; Strekalovsky, A. O.; Strekalovsky, O. V.; Zhuchko, V. E.

2017-06-01

We discuss the manifestations of a new original effect appeared at crossing of the metal foils by fission fragments. We have observed significant mass deficit in the total mass Ms of the fission fragments detected in coincidence with ions knocked out from the foil. It was shown that at the large angles of scattering of the knocked-out ions from the foil predominantly conventional elastic Rutherford scattering takes place. As the result Ms corresponds to the mean mass of the mother system after emission of fission neutrons (no missing mass). In contrast, in near frontal impacts fission fragment misses essential part of its mass. Residual nuclei at least for the fragments from the heavy mass peak show magic nucleon composition.

Algebra Magic Tricks: Algecadabra! Volume 1.

ERIC Educational Resources Information Center

Edwards, Ronald

This resource book contains 20 magic tricks based on the properties of whole numbers that are intended to spark the interest and imagination of students. Following each activity, students are asked to write about their discoveries and to create their own magic tricks. A matrix of skills for all the activities and lists of the materials required…

Algebra Magic Tricks: Algecadabra! Volume 2.

ERIC Educational Resources Information Center

Edwards, Ronald

This resource book contains 15 magic tricks based on the properties of whole numbers that are intended to spark the interest and imagination of students. Following each activity, students are asked to write about their discoveries and to create their own magic tricks. A matrix of skills for all the activities and lists of the materials required…

A COAXIAL MAGIC-T

DTIC Science & Technology

Three different designs of coaxial hybrid junctions having perf ormance analogous to a wave-guide magic -T are discussed. The experimental results...loads, decoupling greater than 70 db can be obtained. An application of the magic -T in phase measurement is described which is independent of the signal amplitude and is similar to the homodyne system of phase measurement.

A CMOS VLSI IC for Real-Time Opto-Electronic Two-Dimensional Histogram Generation

DTIC Science & Technology

1993-12-01

large scale integration) design; MAGIC ; CMOS; optics; image processing; 93 16. PRICE CODE 17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATiON 19...1. Sun SPARCstation ............. .............. 6 2. Magic .................. ................... 6 a. Peg ................. .................. 7 b...38 v APPENDIX B. MAGIC CELL LAYOUTS .... ............ .. 39 APPENDIX C: SIMULATION DATA ....... ............. .. 56 A. FINITE STATE MACHINE

Magical Realist Pathways into and under the Psychotherapeutic Imaginary

ERIC Educational Resources Information Center

Speedy, Jane

2011-01-01

My experience of people's life stories from my work as a narrative therapist consistently destabilised distinctions between imagined/magical and real experiences. I came to realise that the day-to-day magical realist juxtapositions I came upon were encounters with people's daily lives, as lived, that have remained unacknowledged within the…

Glamour and Spelling: Reclaiming Magical Thinking in the Composition Classroom.

ERIC Educational Resources Information Center

Wagner, Julia

It is a good thing to demolish "magical thinking" if it refers to the view of language for which words have fixed, inevitable meanings. Words are often deprived of their meanings and reduced to verbal noises, producing involuntary responses like knee-reflexes. Various critics have discussed and written about the magical aspects of…

Garden Gnomes: Magical or Tacky?

ERIC Educational Resources Information Center

Flynt, Deborah

2012-01-01

Garden gnomes: magical or tacky? Well, art is in the eye of the beholder, and for the author's advanced seventh-grade art class, garden gnomes are magical. Gnomes have a very long history, dating back to medieval times. A fairytale describes them as brownie-like creatures that are nocturnal helpers. In this article, the author describes how her…

A framework for using magic to study the mind.

PubMed

Rensink, Ronald A; Kuhn, Gustav

2014-01-01

Over the centuries, magicians have developed extensive knowledge about the manipulation of the human mind-knowledge that has been largely ignored by psychology. It has recently been argued that this knowledge could help improve our understanding of human cognition and consciousness. But how might this be done? And how much could it ultimately contribute to the exploration of the human mind? We propose here a framework outlining how knowledge about magic can be used to help us understand the human mind. Various approaches-both old and new-are surveyed, in terms of four different levels. The first focuses on the methods in magic, using these to suggest new approaches to existing issues in psychology. The second focuses on the effects that magic can produce, such as the sense of wonder induced by seeing an apparently impossible event. Third is the consideration of magic tricks-methods and effects together-as phenomena of scientific interest in their own right. Finally, there is the organization of knowledge about magic into an informative whole, including the possibility of a science centered around the experience of wonder.

A framework for using magic to study the mind

PubMed Central

Rensink, Ronald A.; Kuhn, Gustav

2015-01-01

Over the centuries, magicians have developed extensive knowledge about the manipulation of the human mind—knowledge that has been largely ignored by psychology. It has recently been argued that this knowledge could help improve our understanding of human cognition and consciousness. But how might this be done? And how much could it ultimately contribute to the exploration of the human mind? We propose here a framework outlining how knowledge about magic can be used to help us understand the human mind. Various approaches—both old and new—are surveyed, in terms of four different levels. The first focuses on the methods in magic, using these to suggest new approaches to existing issues in psychology. The second focuses on the effects that magic can produce, such as the sense of wonder induced by seeing an apparently impossible event. Third is the consideration of magic tricks—methods and effects together—as phenomena of scientific interest in their own right. Finally, there is the organization of knowledge about magic into an informative whole, including the possibility of a science centered around the experience of wonder. PMID:25698983

Observations of VHE γ-Ray Sources with the MAGIC Telescope

NASA Astrophysics Data System (ADS)

Bartko, H.

2008-10-01

The MAGIC telescope with its 17m diameter mirror is today the largest operating single-dish Imaging Air Cherenkov Telescope (IACT). It is located on the Canary Island La Palma, at an altitude of 2200m above sea level, as part of the Roque de los Muchachos European Northern Observatory. The MAGIC telescope detects celestial very high energy γ-radiation in the energy band between about 50 GeV and 10 TeV. Since Autumn of 2004 MAGIC has been taking data routinely, observing various objects like supernova remnants (SNRs), γ-ray binaries, Pulsars, Active Galactic Nuclei (AGN) and Gamma-ray Bursts (GRB). We briefly describe the observational strategy, the procedure implemented for the data analysis, and discuss the results for individual sources. An outlook to the construction of the second MAGIC telescope is given.

[Magical and religious healing in Byzantium].

PubMed

Józsa, László

2010-01-01

Religious and magical ways of healing have been known and practiced since the very beginning of human history. In the present article, the Byzantine philosophical, cultural, historical and "methodological" aspects of this way of healing are discussed. The article outlines the development of magic healing in Byzantium from the 4th to the 15th century. During this period magical therapy included the cult of patron saints--listed by the author--and pleading for divine intervention as well. The activity of "anargyroi" and the use of magical objects and amulets is also discussed in detail. Exorcism was also a part of religious therapy both against psychical and somatical diseases. In early Christianity, and especially in Byzantium the devil or other demons were also supposed to cause various somatical or psychical illnesses by "intrusion" or "internalisation," i.e. by possession or obsession of their victims.

Maximum nonlocality and minimum uncertainty using magic states

NASA Astrophysics Data System (ADS)

Howard, Mark

2015-04-01

We prove that magic states from the Clifford hierarchy give optimal solutions for tasks involving nonlocality and entropic uncertainty with respect to Pauli measurements. For both the nonlocality and uncertainty tasks, stabilizer states are the worst possible pure states, so our solutions have an operational interpretation as being highly nonstabilizer. The optimal strategy for a qudit version of the Clauser-Horne-Shimony-Holt game in prime dimensions is achieved by measuring maximally entangled states that are isomorphic to single-qudit magic states. These magic states have an appealingly simple form, and our proof shows that they are "balanced" with respect to all but one of the mutually unbiased stabilizer bases. Of all equatorial qudit states, magic states minimize the average entropic uncertainties for collision entropy and also, for small prime dimensions, min-entropy, a fact that may have implications for cryptography.

On an algebraic structure of dimensionally reduced magical supergravity theories

NASA Astrophysics Data System (ADS)

Fukuchi, Shin; Mizoguchi, Shun'ya

2018-06-01

We study an algebraic structure of magical supergravities in three dimensions. We show that if the commutation relations among the generators of the quasi-conformal group in the super-Ehlers decomposition are in a particular form, then one can always find a parameterization of the group element in terms of various 3d bosonic fields that reproduces the 3d reduced Lagrangian of the corresponding magical supergravity. This provides a unified treatment of all the magical supergravity theories in finding explicit relations between the 3d dimensionally reduced Lagrangians and particular coset nonlinear sigma models. We also verify that the commutation relations of E 6 (+ 2), the quasi-conformal group for A = C, indeed satisfy this property, allowing the algebraic interpretation of the structure constants and scalar field functions as was done in the F 4 (+ 4) magical supergravity.

Logistical Support of AirLand Operations: Myth or Magic?

DTIC Science & Technology

1992-05-04

I4 May 1992 Master’s Thesis, 4 Aug 91-5 Jun 92 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS .Support of AirLand Operations: Myth or Magic 6. AUTHOR(S) HA•J...SUPPORT OF AIRLAND OPERATIONS: MYTH OR MAGIC A thesis nresented to the Faculty of the U.S. Army Command and General Staff College in oartial fulfillment of...inerati,,,: Myth or Magic . Aprroved by: .Theq is Comni tt-t- fTh~airrnan; J ),I i .5 .a rria A.n . T.T! 3:•, J!. Pnwe r. M’. P. A . " ,ý) VoD" Member

Comparison of HELIX TWT Simulation Using 2-D PIC (Magic), 2-D Modal (Gator), and 1-D Modal (Christine) Methods

DTIC Science & Technology

1998-05-01

Mission Research Corporation MRC/WDC-R-424 COMPARISON OF HELIX TWT SIMULATION USING 2-D PIC ( MAGIC ), 2-D MODAL (GATOR), AND 1-D MODAL (CHRISTINE...BRILLOUIN RUN 9 3.4 OUTLIER ELECTRON EFFECT IN GATOR 12 3.5 EMISSION CONDITION AND NONLAMINAR FLOW IN MAGIC 12 3.6 RADIAL SHEAR 13 SECTION 4. PPM B...Simulation using 2-D PIC ( MAGIC ), 2-D Modal (GATOR) and 1-D Modal (CHRISTINE) methods * D.N. Smithe(a), H. Freund(b), T. M. Antonsen Jr.,(b)’(c), E

Optically guided atom interferometer tuned to magic wavelength

NASA Astrophysics Data System (ADS)

Akatsuka, Tomoya; Takahashi, Tadahiro; Katori, Hidetoshi

2017-11-01

We demonstrate an atom interferometer operating on the 1S0-3P0 clock transition of 87Sr atoms in a “magic” optical guide, where the light shift perturbations of the guiding potential are canceled. As a proof-of-principle demonstration, a Mach-Zehnder interferometer is set horizontally to map the acceleration introduced by the focused optical guide. This magic guide interferometer on the clock transition is applicable to atomic elements where magic wavelengths can be found. Possible applications of the magic guide interferometer, including a hollow-core fiber interferometer and gradiometer, are discussed.

Review of fundamental physics results with the MAGIC telescopes

NASA Astrophysics Data System (ADS)

Rico, Javier

2017-01-01

The MAGIC Cherenkov telescopes are powerful tools for the exploration of the Physics frontiers, addressing topics such as the nature of dark matter and its distribution in the Universe, or the search for quantum gravitational effects in photon propagation. Since the beginning of operations in 2004, MAGIC has studied these questions thanks to hundreds of hours of observations of different targets, and has produced several high-impact results. Those include, significantly, the most constraining limits to the WIMP annihilation cross-section for particle masses above few hundred GeV, from observations of dwarf spheroidal (dSph) satellite galaxies. More recently, we have completed a combined analysis of MAGIC and Fermi-LAT observations of dSphs, obtaining limits for dark matter particle masses between 10 GeV and 100 TeV - the widest mass range ever explored by a single gamma-ray analysis - and improving the previously published Fermi-LAT and MAGIC results by up to a factor of two at certain masses. In this talk, I present an overview of the status and results of MAGIC Fundamental Physics projects, including our latest results concerning searches for Lorentz Invariance violation (LIV), and dark matter searches. I will propose the use of the framework developed for the MAGIC/Fermi-LAT joint analysis for the combination of results from the current generation of gamma-ray and neutrino detectors.

The "Magic" String

ERIC Educational Resources Information Center

Hoover, Todd F.

2010-01-01

The "Magic" String is a discrepant event that includes a canister with what appears to be the end of two strings protruding from opposite sides of it. Due to the way the strings are attached inside the canister, it appears as if the strings can magically switch the way they are connected. When one string end is pulled, the observer's expectation…

Pulling Words Out of a Hat: Magic in ESL Lessons.

ERIC Educational Resources Information Center

Friedenberg, Randi D.

Magic motivates students to talk, and stimulates the affective domain. While watching magic, many people imagine how the effect is accomplished or how they might perform the trick if they were performing. This can be extended into an English lesson by using phrases such as, "If I were a magician, I could..." Total physical response…

The Cultural Work of Magical Realism in Three Young Adult Novels

ERIC Educational Resources Information Center

Latham, Don

2007-01-01

Magical realism as a literary mode is often subversive and transgressive, questioning the values and assumptions of the dominant society that it depicts. Young adult literature, by contrast, is typically thought to serve a socializing function, helping to integrate young readers into adult society. What then is the cultural work of magical realism…

Molecules, magic and forgetful fruit flies: the supernatural science of medical gas research.

PubMed

Mychaskiw, George

2011-09-06

Medical gas research often involves the study of molecules under extraphysiologic conditions, that is, conditions that do not exist in nature. This "supernatural" nature of medical gas research sometimes produces results that appear to be almost "magic" to those schooled in traditional physiology"Any sufficiently advanced technology is indistinguishable from magic".-Arthur C. Clarke.

Development of next-generation mapping populations: Multi-parent Advanced Generation Inter-Cross (MAGIC) and Marker-Assisted Recurrent Selection (MARS) populations in peanut

USDA-ARS?s Scientific Manuscript database

Generation Inter-Cross (MAGIC) and Marker-Assisted Recurrent Selection (MARS) have been proposed and used in many crops to dissect complex traits or QTL. MAGIC allows for dissecting genomic structure, and for improving breeding populations by integrating multiple alleles from different parents. MAR...

Elementary School Teachers' Perceptions toward ICT: The Case of Using Magic Board for Teaching Mathematics

ERIC Educational Resources Information Center

Yuan, Yuan; Lee, Chun-Yi

2012-01-01

This study aims at investigating elementary school teachers' perceptions toward to the use of ICT. Magic Board, an interactive web-based environment which provides a set of virtual manipulatives for elementary mathematics, is used as the case of ICT. After participating in Magic Board workshops, 250 elementary school teachers in Taiwan responded…

77 FR 70432 - Magic Valley Pipeline, L.P.; Notice of Filing

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-26

... Pipeline, L.P.; Notice of Filing Take notice that on November 15, 2012, Magic Valley Pipeline, L.P. (Magic...: 5:00 p.m. Eastern Time on Tuesday, November 27, 2012. Dated: November 19, 2012. Kimberly D. Bose, Secretary. [FR Doc. 2012-28544 Filed 11-23-12; 8:45 am] BILLING CODE 6717-01-P ...

The Magnetics Information Consortium (MagIC)

NASA Astrophysics Data System (ADS)

Johnson, C.; Constable, C.; Tauxe, L.; Koppers, A.; Banerjee, S.; Jackson, M.; Solheid, P.

2003-12-01

The Magnetics Information Consortium (MagIC) is a multi-user facility to establish and maintain a state-of-the-art relational database and digital archive for rock and paleomagnetic data. The goal of MagIC is to make such data generally available and to provide an information technology infrastructure for these and other research-oriented databases run by the international community. As its name implies, MagIC will not be restricted to paleomagnetic or rock magnetic data only, although MagIC will focus on these kinds of information during its setup phase. MagIC will be hosted under EarthRef.org at http://earthref.org/MAGIC/ where two "integrated" web portals will be developed, one for paleomagnetism (currently functional as a prototype that can be explored via the http://earthref.org/databases/PMAG/ link) and one for rock magnetism. The MagIC database will store all measurements and their derived properties for studies of paleomagnetic directions (inclination, declination) and their intensities, and for rock magnetic experiments (hysteresis, remanence, susceptibility, anisotropy). Ultimately, this database will allow researchers to study "on the internet" and to download important data sets that display paleo-secular variations in the intensity of the Earth's magnetic field over geological time, or that display magnetic data in typical Zijderveld, hysteresis/FORC and various magnetization/remanence diagrams. The MagIC database is completely integrated in the EarthRef.org relational database structure and thus benefits significantly from already-existing common database components, such as the EarthRef Reference Database (ERR) and Address Book (ERAB). The ERR allows researchers to find complete sets of literature resources as used in GERM (Geochemical Earth Reference Model), REM (Reference Earth Model) and MagIC. The ERAB contains addresses for all contributors to the EarthRef.org databases, and also for those who participated in data collection, archiving and analysis in the magnetic studies. Integration with these existing components will guarantee direct traceability to the original sources of the MagIC data and metadata. The MagIC database design focuses around the general workflow that results in the determination of typical paleomagnetic and rock magnetic analyses. This ensures that individual data points can be traced between the actual measurements and their associated specimen, sample, site, rock formation and locality. This permits a distinction between original and derived data, where the actual measurements are performed at the specimen level, and data at the sample level and higher are then derived products in the database. These relations will also allow recalculation of derived properties, such as site means, when new data becomes available for a specific locality. Data contribution to the MagIC database is critical in achieving a useful research tool. We have developed a standard data and metadata template that can be used to provide all data at the same time as publication. Software tools are provided to facilitate easy population of these templates. The tools allow for the import/export of data files in a delimited text format, and they provide some advanced functionality to validate data and to check internal coherence of the data in the template. During and after publication these standardized MagIC templates will be stored in the ERR database of EarthRef.org from where they can be downloaded at all times. Finally, the contents of these template files will be automatically parsed into the online relational database.

[Research on improving spectrum resolution of optimized Wollaston prism array].

PubMed

Zhang, Peng; Wang, Jian-Rong; Zhang, Guo-Chen; Hou, Wen

2011-11-01

In order to not affect the image quality of interference fringes on the basis of the structure by increasing the structure angle of Wollaston prism to improve spectrum resolution, the authors optimized the structure of Wollaston prism. Calculating the function of the splitting angle and the structure angle, analysis indicated that taking the isosceles triangle prism with the same nature of the second wedge-shaped prism after the Wollaston prism, which makes the o and e light parallel to the optical axis, and alpha=0 degrees, the imaging interference fringes are no longer affected by changes in the splitting angle. Several optimized Wollaston prisms were made as an array to improve the spectral resolution. Experiments used traditional and optimized Wollaston prism array to detect the spectrum of the 980 nm laser. Experimental data showed that using optimized Wollaston prism array gets a clearer contrast of interference fringes, and the spectral data with Fourier transform are more accurate with DSP.

Introducing a New Interface for the Online MagIC Database by Integrating Data Uploading, Searching, and Visualization

NASA Astrophysics Data System (ADS)

Jarboe, N.; Minnett, R.; Constable, C.; Koppers, A. A.; Tauxe, L.

2013-12-01

The Magnetics Information Consortium (MagIC) is dedicated to supporting the paleomagnetic, geomagnetic, and rock magnetic communities through the development and maintenance of an online database (http://earthref.org/MAGIC/), data upload and quality control, searches, data downloads, and visualization tools. While MagIC has completed importing some of the IAGA paleomagnetic databases (TRANS, PINT, PSVRL, GPMDB) and continues to import others (ARCHEO, MAGST and SECVR), further individual data uploading from the community contributes a wealth of easily-accessible rich datasets. Previously uploading of data to the MagIC database required the use of an Excel spreadsheet using either a Mac or PC. The new method of uploading data utilizes an HTML 5 web interface where the only computer requirement is a modern browser. This web interface will highlight all errors discovered in the dataset at once instead of the iterative error checking process found in the previous Excel spreadsheet data checker. As a web service, the community will always have easy access to the most up-to-date and bug free version of the data upload software. The filtering search mechanism of the MagIC database has been changed to a more intuitive system where the data from each contribution is displayed in tables similar to how the data is uploaded (http://earthref.org/MAGIC/search/). Searches themselves can be saved as a permanent URL, if desired. The saved search URL could then be used as a citation in a publication. When appropriate, plots (equal area, Zijderveld, ARAI, demagnetization, etc.) are associated with the data to give the user a quicker understanding of the underlying dataset. The MagIC database will continue to evolve to meet the needs of the paleomagnetic, geomagnetic, and rock magnetic communities.

Magical thinking and decision-making strategies among late adolescent regular gamblers: A mediation model.

PubMed

Passanisi, Alessia; Craparo, Giuseppe; Pace, Ugo

2017-08-01

In the present study, the relation between the tendency to seek supernatural connections between external events and one's own thoughts, words, and actions and gambling among late adolescents has been studied. Psychologists have called this tendency magical thinking. The principal aim of the present study was to test the fit of an explanatory model of risk that starts from magical thinking and passes through maladaptive decision-making strategies, culminating with pathological gambling. Two hundred twenty-two Italian late adolescents, regularly attending bingo halls, aged between 19 and 21 years, completed measures on magical thinking, decision-making strategies, and gambling. Results highlight that young adults adopting dysfunctional modes of thought (i.e. magical thinking) tend to engage with maladaptive styles of decision-making that predispose them to gamble. Copyright © 2017 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

High Frequency Dynamic Nuclear Polarization

PubMed Central

Ni, Qing Zhe; Daviso, Eugenio; Can, Thach V.; Markhasin, Evgeny; Jawla, Sudheer K.; Swager, Timothy M.; Temkin, Richard J.; Herzfeld, Judith; Griffin, Robert G.

2013-01-01

Conspectus During the three decades 1980–2010, magic angle spinning (MAS) NMR developed into the method of choice to examine many chemical, physical and biological problems. In particular, a variety of dipolar recoupling methods to measure distances and torsion angles can now constrain molecular structures to high resolution. However, applications are often limited by the low sensitivity of the experiments, due in large part to the necessity of observing spectra of low-γ nuclei such as the I = ½ species 13C or 15N. The difficulty is still greater when quadrupolar nuclei, like 17O or 27Al, are involved. This problem has stimulated efforts to increase the sensitivity of MAS experiments. A particularly powerful approach is dynamic nuclear polarization (DNP) which takes advantage of the higher equilibrium polarization of electrons (which conventionally manifests in the great sensitivity advantage of EPR over NMR). In DNP, the sample is doped with a stable paramagnetic polarizing agent and irradiated with microwaves to transfer the high polarization in the electron spin reservoir to the nuclei of interest. The idea was first explored by Overhauser and Slichter in 1953. However, these experiments were carried out on static samples, at magnetic fields that are low by current standards. To be implemented in contemporary MAS NMR experiments, DNP requires microwave sources operating in the subterahertz regime — roughly 150–660 GHz — and cryogenic MAS probes. In addition, improvements were required in the polarizing agents, because the high concentrations of conventional radicals that are required to produce significant enhancements compromise spectral resolution. In the last two decades scientific and technical advances have addressed these problems and brought DNP to the point where it is achieving wide applicability. These advances include the development of high frequency gyrotron microwave sources operating in the subterahertz frequency range. In addition, low temperature MAS probes were developed that permit in-situ microwave irradiation of the samples. And, finally, biradical polarizing agents were developed that increased the efficiency of DNP experiments by factors of ~4 at considerably lower paramagnet concentrations. Collectively these developments have made it possible to apply DNP on a routine basis to a number of different scientific endeavors, most prominently in the biological and material sciences. This Account reviews these developments, including the primary mechanisms used to transfer polarization in high frequency DNP, and the current choice of microwave sources and biradical polarizing agents. In addition, we illustrate the utility of the technique with a description of applications to membrane and amyloid proteins that emphasizes the unique structural information that is available in these two cases. PMID:23597038

Molecules, magic and forgetful fruit flies: the supernatural science of medical gas research

PubMed Central

2011-01-01

Medical gas research often involves the study of molecules under extraphysiologic conditions, that is, conditions that do not exist in nature. This "supernatural" nature of medical gas research sometimes produces results that appear to be almost "magic" to those schooled in traditional physiology "Any sufficiently advanced technology is indistinguishable from magic". -Arthur C. Clarke PMID:22146602

The Magical Classroom: Exploring Science, Language, and Perception with Children.

ERIC Educational Resources Information Center

Strauss, Michael J.

The science of magic is the subject of this book which also examines how to help children experience and describe the world, how to experiment and ask questions about it, and how to make decisions about what is true and what is not. Background information about the relationship between magic and science and the nature of effects and illusions are…

Overview of MAGIC results

NASA Astrophysics Data System (ADS)

Rico, Javier; MAGIC Collaboration

2016-04-01

MAGIC is a system of two 17-m diameter Cherenkov telescopes, located at the Observatorio del Roque de los Muchachos, in the Canary island La Palma (Spain). MAGIC performs astronomical observations of gamma-ray sources in the energy range between 50 GeV and 10 TeV. The first MAGIC telescope has been operating since 2004, and in 2009 the system was completed with the second one. During 2011 and 2012 the electronics for the readout system were fully upgraded, and the camera of the first telescope replaced. After that, no major hardware interventions are foreseen in the next years, and the experiment has undertaken a final period of steady astronomical observations. MAGIC studies particle acceleration in the most violent cosmic environments, such as active galactic nuclei, gamma-ray bursts, pulsars, supernova remnants or binary systems. In addition, it addresses some fundamental questions of Physics, such as the origin of Galactic cosmic rays and the nature of dark matter. Moreover, by observing the gamma-ray emission from sources at cosmological distances, we measure the intensity and evolution of the extragalactic background radiation, and perform tests of Lorentz Invariance. In this paper I present the status and some of the latest results of the MAGIC gamma-ray telescopes.

Real time dynamics of Si magic clusters mediating phase transformation: Si(111)-(1 × 1) to (7 × 7) reconstruction revisited

NASA Astrophysics Data System (ADS)

Ong, Wei Jie; Tok, Eng Soon

2012-07-01

Using Scanning Tunneling Microscope (STM), we show that the surface undergoes phase transformation from disordered "1 × 1" to (7 × 7) reconstruction which is mediated by the formation of Si magic clusters. Mono-disperse Si magic clusters of size ~ 13.5 ± 0.5 Å can be formed by heating the Si(111) surface to 1200 °C and quenching it to room temperature at cooling rates of at least 100 °C/min. The structure consists of 3 tetra-clusters of size ~ 4.5 Ǻ similar to the Si magic clusters that were formed from Si adatoms deposited by Si solid source on Si(111)-(7 × 7) [1]. Using real time STM scanning to probe the surface at ~ 400 °C, we show that Si magic clusters pop up from the (1 × 1) surface and form spontaneously during the phase transformation. This is attributed to the difference in atomic density between "disordered 1 × 1" and (7 × 7) surface structures which lead to the release of excess Si atoms onto the surface as magic clusters.

The relationship between magical thinking, inferential confusion and obsessive-compulsive symptoms.

PubMed

Goods, N A R; Rees, C S; Egan, S J; Kane, R T

2014-01-01

Inferential confusion is an under-researched faulty reasoning process in obsessive-compulsive disorder (OCD). Based on an overreliance on imagined possibilities, it shares similarities with the extensively researched construct of thought-action fusion (TAF). While TAF has been proposed as a specific subset of the broader construct of magical thinking, the relationship between inferential confusion and magical thinking is unexplored. The present study investigated this relationship, and hypothesised that magical thinking would partially mediate the relationship between inferential confusion and obsessive-compulsive symptoms. A non-clinical sample of 201 participants (M = 34.94, SD = 15.88) were recruited via convenience sampling. Regression analyses found the hypothesised mediating relationship was supported, as magical thinking did partially mediate the relationship between inferential confusion and OC symptoms. Interestingly, inferential confusion had the stronger relationship with OC symptoms in comparison to the other predictor variables. Results suggest that inferential confusion can both directly and indirectly (via magical thinking) impact on OC symptoms. Future studies with clinical samples should further investigate these constructs to determine whether similar patterns emerge, as this may eventually inform which cognitive errors to target in treatment of OCD.

Does magical thinking produce neutralising behaviour? An experimental investigation.

PubMed

Bocci, Laura; Gordon, P Kenneth

2007-08-01

Magical thinking is of relevance to obsessive compulsive disorder (OCD), and has been most widely investigated in relation to the cognitive bias known as thought-action fusion (TAF). This is seen as playing a role in the formation of fears about responsibility for harm. We suggest that magical thinking may also characterise some types of neutralising behaviour, which arise in response to those fears, and are a hallmark of the disorder. In an experimental study of 51 undergraduate students, we assessed whether the use of neutralising behaviours in response to an induction of fears of increasing likelihood for harm is related to a propensity for magical thinking. The 75.5% of participants demonstrated at least one form of neutralising behaviour in response to a TAF-induction task. Neutralising was associated with stronger and more persistent responses to the task, and with questionnaire measures of magical ideation. Those who neutralised did not report higher levels of OCD symptoms. It appears that neutralising is a common response in circumstances that provoke a sense of responsibility for harm. Its occurrence may be linked to magical thinking, however, the results from this experimental investigation suggested that this process may not be specific to OCD.

Characterization of a novel two dimensional diode array the "magic plate" as a radiation detector for radiation therapy treatment.

PubMed

Wong, J H D; Fuduli, I; Carolan, M; Petasecca, M; Lerch, M L F; Perevertaylo, V L; Metcalfe, P; Rosenfeld, A B

2012-05-01

Intensity modulated radiation therapy (IMRT) utilizes the technology of multileaf collimators to deliver highly modulated and complex radiation treatment. Dosimetric verification of the IMRT treatment requires the verification of the delivered dose distribution. Two dimensional ion chamber or diode arrays are gaining popularity as a dosimeter of choice due to their real time feedback compared to film dosimetry. This paper describes the characterization of a novel 2D diode array, which has been named the "magic plate" (MP). It was designed to function as a 2D transmission detector as well as a planar detector for dose distribution measurements in a solid water phantom for the dosimetric verification of IMRT treatment delivery. The prototype MP is an 11 × 11 detector array based on thin (50 μm) epitaxial diode technology mounted on a 0.6 mm thick Kapton substrate using a proprietary "drop-in" technology developed by the Centre for Medical Radiation Physics, University of Wollongong. A full characterization of the detector was performed, including radiation damage study, dose per pulse effect, percent depth dose comparison with CC13 ion chamber and build up characteristics with a parallel plane ion chamber measurements, dose linearity, energy response and angular response. Postirradiated magic plate diodes showed a reproducibility of 2.1%. The MP dose per pulse response decreased at higher dose rates while at lower dose rates the MP appears to be dose rate independent. The depth dose measurement of the MP agrees with ion chamber depth dose measurements to within 0.7% while dose linearity was excellent. MP showed angular response dependency due to the anisotropy of the silicon diode with the maximum variation in angular response of 10.8% at gantry angle 180°. Angular dependence was within 3.5% for the gantry angles ± 75°. The field size dependence of the MP at isocenter agrees with ion chamber measurement to within 1.1%. In the beam perturbation study, the surface dose increased by 12.1% for a 30 × 30 cm(2) field size at the source to detector distance (SDD) of 80 cm whilst the transmission for the MP was 99%. The radiation response of the magic plate was successfully characterized. The array of epitaxial silicon based detectors with "drop-in" packaging showed properties suitable to be used as a simplified multipurpose and nonperturbing 2D radiation detector for radiation therapy dosimetric verification.

Working wonders? investigating insight with magic tricks.

PubMed

Danek, Amory H; Fraps, Thomas; von Müller, Albrecht; Grothe, Benedikt; Ollinger, Michael

2014-02-01

We propose a new approach to differentiate between insight and noninsight problem solving, by introducing magic tricks as problem solving domain. We argue that magic tricks are ideally suited to investigate representational change, the key mechanism that yields sudden insight into the solution of a problem, because in order to gain insight into the magicians' secret method, observers must overcome implicit constraints and thus change their problem representation. In Experiment 1, 50 participants were exposed to 34 different magic tricks, asking them to find out how the trick was accomplished. Upon solving a trick, participants indicated if they had reached the solution either with or without insight. Insight was reported in 41.1% of solutions. The new task domain revealed differences in solution accuracy, time course and solution confidence with insight solutions being more likely to be true, reached earlier, and obtaining higher confidence ratings. In Experiment 2, we explored which role self-imposed constraints actually play in magic tricks. 62 participants were presented with 12 magic tricks. One group received verbal cues, providing solution relevant information without giving the solution away. The control group received no informative cue. Experiment 2 showed that participants' constraints were suggestible to verbal cues, resulting in higher solution rates. Thus, magic tricks provide more detailed information about the differences between insightful and noninsightful problem solving, and the underlying mechanisms that are necessary to have an insight. Copyright © 2013 Elsevier B.V. All rights reserved.

Uploading, Searching and Visualizing of Paleomagnetic and Rock Magnetic Data in the Online MagIC Database

NASA Astrophysics Data System (ADS)

Minnett, R.; Koppers, A.; Tauxe, L.; Constable, C.; Donadini, F.

2007-12-01

The Magnetics Information Consortium (MagIC) is commissioned to implement and maintain an online portal to a relational database populated by both rock and paleomagnetic data. The goal of MagIC is to archive all available measurements and derived properties from paleomagnetic studies of directions and intensities, and for rock magnetic experiments (hysteresis, remanence, susceptibility, anisotropy). MagIC is hosted under EarthRef.org at http://earthref.org/MAGIC/ and will soon implement two search nodes, one for paleomagnetism and one for rock magnetism. Currently the PMAG node is operational. Both nodes provide query building based on location, reference, methods applied, material type and geological age, as well as a visual map interface to browse and select locations. Users can also browse the database by data type or by data compilation to view all contributions associated with well known earlier collections like PINT, GMPDB or PSVRL. The query result set is displayed in a digestible tabular format allowing the user to descend from locations to sites, samples, specimens and measurements. At each stage, the result set can be saved and, where appropriate, can be visualized by plotting global location maps, equal area, XY, age, and depth plots, or typical Zijderveld, hysteresis, magnetization and remanence diagrams. User contributions to the MagIC database are critical to achieving a useful research tool. We have developed a standard data and metadata template (version 2.3) that can be used to format and upload all data at the time of publication in Earth Science journals. Software tools are provided to facilitate population of these templates within Microsoft Excel. These tools allow for the import/export of text files and provide advanced functionality to manage and edit the data, and to perform various internal checks to maintain data integrity and prepare for uploading. The MagIC Contribution Wizard at http://earthref.org/MAGIC/upload.htm executes the upload and takes only a few minutes to process tens of thousands of data records. The standardized MagIC template files are stored in the digital archives of EarthRef.org where they remain available for download by the public (in both text and Excel format). Finally, the contents of these template files are automatically parsed into the online relational database, making the data available for online searches in the paleomagnetic and rock magnetic search nodes. During the upload process the owner has the option of keeping the contribution private so it can be viewed in the context of other data sets and visualized using the suite of MagIC plotting tools. Alternatively, the new data can be password protected and shared with a group of users at the contributor's discretion. Once they are published and the owner is comfortable making the upload publicly accessible, the MagIC Editing Committee reviews the contribution for adherence to the MagIC data model and conventions to ensure a high level of data integrity.

Performance analysis of a CsI-based flat panel detector in a cone beam variable resolution x-ray system

NASA Astrophysics Data System (ADS)

Dahi, Bahram; Keyes, Gary S.; Rendon, David A.; DiBianca, Frank A.

2007-03-01

A new Cone-Beam CT (CBCT) system is introduced that uses the concept of Variable Resolution X-ray (VRX) detection, which has previously been demonstrated to significantly increase spatial resolution for small objects. An amorphous silicon Flat Panel Detector (FPD) with a CsI scintillator (PaxScan 2020, Varian, Salt Lake City, UT) is coupled with a micro-focus x-ray tube (35 - 80 kVp, 10 - 250 μA) to form a CBCT. The FPD is installed on a rotating arm that can be adjusted to any angle θ, called the VRX angle, between 90° and 0° with respect to the x-ray direction. A VRX angle of 90° for the detector corresponds to a conventional CBCT whereas a VRX angle of 30° means that the detector is tilted 90° - 30° = 60° from its perpendicular position. Tilting the FPD in this manner reduces both the line-spread function width and the sampling distance by a factor of sin(θ), thereby increasing detector spatial resolution proportionately. An in-house phantom is used to measure the MTF of the reconstructed CT images using different VRX angles. An increase by a factor of 1.67 +/- 0.007 is observed in the MTF cutoff frequency at 30° compared to 90° in images acquired at 75 kVp. Expected theoretical value for this case is 2.0. The new Cone-Beam Variable Resolution X-ray (CB-VRX) CT system is expected to significantly improve the images acquired from small objects - such as small animals - while exploiting the opportunities offered by a conventional CBCT.