Resonant ultrasound spectroscopy

DOEpatents

Migliori, Albert

1991-01-01

A resonant ultrasound spectroscopy method provides a unique characterization of an object for use in distinguishing similar objects having physical differences greater than a predetermined tolerance. A resonant response spectrum is obtained for a reference object by placing excitation and detection transducers at any accessible location on the object. The spectrum is analyzed to determine the number of resonant response peaks in a predetermined frequency interval. The distribution of the resonance frequencies is then characterized in a manner effective to form a unique signature of the object. In one characterization, a small frequency interval is defined and stepped though the spectrum frequency range. Subsequent objects are similarly characterized where the characterizations serve as signatures effective to distinguish objects that differ from the reference object by more than the predetermined tolerance.

DC superconducting quantum interference device usable in nuclear quadrupole resonance and zero field nuclear magnetic spectrometers

DOEpatents

Fan, N.Q.; Clarke, J.

1993-10-19

A spectrometer for measuring the nuclear quadrupole resonance spectra or the zero-field nuclear magnetic resonance spectra generated by a sample is disclosed. The spectrometer uses an amplifier having a dc SQUID operating in a flux-locked loop for generating an amplified output as a function of the intensity of the signal generated by the sample. The flux-locked loop circuit includes an integrator. The amplifier also includes means for preventing the integrator from being driven into saturation. As a result, the time for the flux-locked loop to recover from the excitation pulses generated by the spectrometer is reduced. 7 figures.

DC superconducting quantum interference device usable in nuclear quadrupole resonance and zero field nuclear magnetic spectrometers

DOEpatents

Fan, Non Q.; Clarke, John

1993-01-01

A spectrometer for measuring the nuclear quadrupole resonance spectra or the zero-field nuclear magnetic resonance spectra generated by a sample is disclosed. The spectrometer uses an amplifier having a dc SQUID operating in a flux-locked loop for generating an amplified output as a function of the intensity of the signal generated by the sample. The flux-locked loop circuit includes an integrator. The amplifier also includes means for preventing the integrator from being driven into saturation. As a result, the time for the flux-locked loop to recover from the excitation pulses generated by the spectrometer is reduced.

Torque-mixing magnetic resonance spectroscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Losby, Joseph; Fani Sani, Fatemeh; Grandmont, Dylan T.; Diao, Zhu; Belov, Miro; Burgess, Jacob A.; Compton, Shawn R.; Hiebert, Wayne K.; Vick, Doug; Mohammad, Kaveh; Salimi, Elham; Bridges, Gregory E.; Thomson, Douglas J.; Freeman, Mark R.

2016-10-01

An optomechanical platform for magnetic resonance spectroscopy will be presented. The method relies on frequency mixing of orthogonal RF fields to yield a torque amplitude (arising from the transverse component of a precessing dipole moment, in analogy to magnetic resonance detection by electromagnetic induction) on a miniaturized resonant mechanical torsion sensor. In contrast to induction, the method is fully broadband and allows for simultaneous observation of the equilibrium net magnetic moment alongside the associated magnetization dynamics. To illustrate the method, comprehensive electron spin resonance spectra of a mesoscopic, single-crystal YIG disk at room temperature will be presented, along with situations where torque spectroscopy can offer complimentary information to existing magnetic resonance detection techniques. The authors are very grateful for support from NSERC, CRC, AITF, and NINT. Reference: Science 350, 798 (2015).

79/81Br nuclear quadrupole resonance spectroscopic characterization of halogen bonds in supramolecular assemblies.

PubMed

Cerreia Vioglio, P; Szell, P M J; Chierotti, M R; Gobetto, R; Bryce, D L

2018-05-28

Despite the applicability of solid-state NMR to study the halogen bond, the direct NMR detection of 79/81 Br covalently bonded to carbon remains impractical due to extremely large spectral widths, even at ultra-high magnetic fields. In contrast, nuclear quadrupole resonance (NQR) offers comparatively sharp resonances. Here, we demonstrate the abilities of 79/81 Br NQR to characterize the electronic changes in the C-Br···N halogen bonding motifs found in supramolecular assemblies constructed from 1,4-dibromotetrafluorobenzene and nitrogen-containing heterocycles. An increase in the bromine quadrupolar coupling constant is observed, which correlates linearly with the halogen bond distance ( d Br···N ). Notably, 79/81 Br NQR is able to distinguish between two symmetry-independent halogen bonds in the same crystal structure. This approach offers a rapid and reliable indication for the occurrence of a halogen bond, with experimental times limited only by the observation of 79/81 Br NQR resonances.

Plasmon-Induced Magnetic Resonance Enhanced Raman Spectroscopy.

PubMed

Chen, Shu; Zhang, Yuejiao; Shih, Tien-Mo; Yang, Weimin; Hu, Shu; Hu, Xiaoyan; Li, Jianfeng; Ren, Bin; Mao, Bingwei; Yang, Zhilin; Tian, Zhongqun

2018-04-11

Plasmon-induced magnetic resonance has shown great potentials in optical metamaterials, chemical (bio)-sensing, and surface-enhanced spectroscopies. Here, we have theoretically and experimentally revealed (1) a correspondence of the strongest near-field response to the far-field scattering valley and (2) a significant improvement in Raman signals of probing molecules by the plasmon-induced magnetic resonance. These revelations are accomplished by designing a simple and practical metallic nanoparticle-film plasmonic system that generates magnetic resonances at visible-near-infrared frequencies. Our work may provide new insights for understanding the enhancement mechanism of various plasmon-enhanced spectroscopies and also helps further explore light-matter interactions at the nanoscale.

Enhancing nuclear quadrupole resonance (NQR) signature detection leveraging interference suppression algorithms

NASA Astrophysics Data System (ADS)

DeBardelaben, James A.; Miller, Jeremy K.; Myrick, Wilbur L.; Miller, Joel B.; Gilbreath, G. Charmaine; Bajramaj, Blerta

2012-06-01

Nuclear quadrupole resonance (NQR) is a radio frequency (RF) magnetic spectroscopic technique that has been shown to detect and identify a wide range of explosive materials containing quadrupolar nuclei. The NQR response signal provides a unique signature of the material of interest. The signal is, however, very weak and can be masked by non-stationary RF interference (RFI) and thermal noise, limiting detection distance. In this paper, we investigate the bounds on the NQR detection range for ammonium nitrate. We leverage a low-cost RFI data acquisition system composed of inexpensive B-field sensing and commercial-off-the-shelf (COTS) software-defined radios (SDR). Using collected data as RFI reference signals, we apply adaptive filtering algorithms to mitigate RFI and enable NQR detection techniques to approach theoretical range bounds in tactical environments.

Ring resonant cavities for spectroscopy

DOEpatents

Zare, R.N.; Martin, J.; Paldus, B.A.; Xie, J.

1999-06-15

Ring-shaped resonant cavities for spectroscopy allow a reduction in optical feedback to the light source, and provide information on the interaction of both s- and p-polarized light with samples. A laser light source is locked to a single cavity mode. An intracavity acousto-optic modulator may be used to couple light into the cavity. The cavity geometry is particularly useful for Cavity Ring-Down Spectroscopy (CRDS). 6 figs.

Ring resonant cavities for spectroscopy

DOEpatents

Zare, Richard N.; Martin, Juergen; Paldus, Barbara A.; Xie, Jinchun

1999-01-01

Ring-shaped resonant cavities for spectroscopy allow a reduction in optical feedback to the light source, and provide information on the interaction of both s- and p-polarized light with samples. A laser light source is locked to a single cavity mode. An intracavity acousto-optic modulator may be used to couple light into the cavity. The cavity geometry is particularly useful for Cavity Ring-Down Spectroscopy (CRDS).

A versatile computer-controlled pulsed nuclear quadrupole resonance spectrometer

NASA Astrophysics Data System (ADS)

Fisher, Gregory; MacNamara, Ernesto; Santini, Robert E.; Raftery, Daniel

1999-12-01

A new, pulsed nuclear quadrupole resonance (NQR) spectrometer capable of performing a variety of pulsed and swept experiments is described. The spectrometer features phase locked, superheterodyne detection using a commercial spectrum analyzer and a fully automatic, computer-controlled tuning and matching network. The tuning and matching network employs stepper motors which turn high power air gap capacitors in a "moving grid" optimization strategy to minimize the reflected power from a directional coupler. In the duplexer circuit, digitally controlled relays are used to switch different lengths of coax cable appropriate for the different radio frequencies. A home-built pulse programmer card controls the timing of radio frequency pulses sent to the probe, while data acquisition and control software is written in Microsoft Quick Basic. Spin-echo acquisition experiments are typically used to acquire the data, although a variety of pulse sequences can be employed. Scan times range from one to several hours depending upon the step resolution and the spectral range required for each experiment. Pure NQR spectra of NaNO2 and 3-aminopyridine are discussed.

Observation of Excited Quadrupole-Bound States in Cold Anions

NASA Astrophysics Data System (ADS)

Zhu, Guo-Zhu; Liu, Yuan; Wang, Lai-Sheng

2017-07-01

We report the first observation of an excited quadrupole-bound state (QBS) in an anion. High-resolution photoelectron imaging of cryogenically cooled 4-cyanophenoxide (4 CP- ) anions yields an electron detachment threshold of 24 927 cm-1 . The photodetachment spectrum reveals a resonant transition 20 cm-1 below the detachment threshold, which is attributed to an excited QBS of 4 CP- because neutral 4CP has a large quadrupole moment with a negligible dipole moment. The QBS is confirmed by observation of seventeen above-threshold resonances due to autodetachment from vibrational levels of the QBS.

Perspective: Two-dimensional resonance Raman spectroscopy

NASA Astrophysics Data System (ADS)

Molesky, Brian P.; Guo, Zhenkun; Cheshire, Thomas P.; Moran, Andrew M.

2016-11-01

Two-dimensional resonance Raman (2DRR) spectroscopy has been developed for studies of photochemical reaction mechanisms and structural heterogeneity in complex systems. The 2DRR method can leverage electronic resonance enhancement to selectively probe chromophores embedded in complex environments (e.g., a cofactor in a protein). In addition, correlations between the two dimensions of the 2DRR spectrum reveal information that is not available in traditional Raman techniques. For example, distributions of reactant and product geometries can be correlated in systems that undergo chemical reactions on the femtosecond time scale. Structural heterogeneity in an ensemble may also be reflected in the 2D spectroscopic line shapes of both reactive and non-reactive systems. In this perspective article, these capabilities of 2DRR spectroscopy are discussed in the context of recent applications to the photodissociation reactions of triiodide and myoglobin. We also address key differences between the signal generation mechanisms for 2DRR and off-resonant 2D Raman spectroscopies. Most notably, it has been shown that these two techniques are subject to a tradeoff between sensitivity to anharmonicity and susceptibility to artifacts. Overall, recent experimental developments and applications of the 2DRR method suggest great potential for the future of the technique.

Extended nuclear quadrupole resonance study of the heavy-fermion superconductor PuCoGa5

NASA Astrophysics Data System (ADS)

Koutroulakis, G.; Yasuoka, H.; Tobash, P. H.; Mitchell, J. N.; Bauer, E. D.; Thompson, J. D.

2016-10-01

PuCoGa5 has emerged as a prototypical heavy-fermion superconductor, with its transition temperature (Tc≃18.5 K) being the highest amongst such materials. Nonetheless, a clear description as to what drives the superconducting pairing is still lacking, rendered complicated by the notoriously intricate nature of plutonium's 5 f valence electrons. Here, we present a detailed Ga,7169 nuclear quadrupole resonance (NQR) study of PuCoGa5, concentrating on the system's normal state properties near to Tc and aiming to detect distinct signatures of possible pairing mechanisms. In particular, the quadrupole frequency and spin-lattice relaxation rate were measured for the two crystallographically inequivalent Ga sites and for both Ga isotopes, in the temperature range 1.6-300 K. No evidence of significant charge fluctuations is found from the NQR observables. On the contrary, the low-energy dynamics is dominated by anisotropic spin fluctuations with strong, nearly critical, in-plane character, which are effectively identical to the case of the sister compound PuCoIn5. These findings are discussed within the context of different theoretical proposals for the unconventional pairing mechanism in heavy-fermion superconductors.

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

NASA Astrophysics Data System (ADS)

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

2012-07-01

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

Frequency selective detection of nuclear quadrupole resonance (NQR) spin echoes

NASA Astrophysics Data System (ADS)

Somasundaram, Samuel D.; Jakobsson, Andreas; Smith, John A. S.; Althoefer, Kaspar A.

2006-05-01

Nuclear Quadrupole Resonance (NQR) is a radio frequency (RF) technique that can be used to detect the presence of quadrupolar nuclei, such as the 14N nucleus prevalent in many explosives and narcotics. The technique has been hampered by low signal-to-noise ratios and is further aggravated by the presence of RF interference (RFI). To ensure accurate detection, proposed detectors should exploit the rich form of the NQR signal. Furthermore, the detectors should also be robust to any remaining residual interference, left after suitable RFI mitigation has been employed. In this paper, we propose a new NQR data model, particularly for the realistic case where multiple pulse sequences are used to generate trains of spin echoes. Furthermore, we refine two recently proposed approximative maximum likelihood (AML) detectors, enabling the algorithm to optimally exploit the data model of the entire echo train and also incorporate knowledge of the temperature dependent spin-echo decay time. The AML-based detectors ensure accurate detection and robustness against residual RFI, even when the temperature of the sample is not precisely known, by exploiting the dependencies of the NQR resonant lines on temperature. Further robustness against residual interference is gained as the proposed detector is frequency selective; exploiting only those regions of the spectrum where the NQR signal is expected. Extensive numerical evaluations based on both simulated and measured NQR data indicate that the proposed Frequency selective Echo Train AML (FETAML) detector offers a significant improvement as compared to other existing detectors.

Extended nuclear quadrupole resonance study of the heavy-fermion superconductor PuCoGa 5

DOE PAGES

Koutroulakis, Georgios; Yasuoka, Hiroshi; Tobash, Paul H.; ...

2016-10-10

PuCoGa 5 has emerged as a prototypical heavy-fermion superconductor, with its transition temperature (T c ≃ 18.5 K) being the highest amongst such materials. Nonetheless, a clear description as to what drives the superconducting pairing is still lacking, rendered complicated by the notoriously intricate nature of plutonium's 5f valence electrons. Here, we present a detailed 69,71Ga nuclear quadrupole resonance (NQR) study of PuCoGa 5, concentrating on the system's normal state properties near to T c and aiming to detect distinct signatures of possible pairing mechanisms. In particular, the quadrupole frequency and spin-lattice relaxation rate were measured for the two crystallographicallymore » inequivalent Ga sites and for both Ga isotopes, in the temperature range 1.6–300 K. No evidence of significant charge fluctuations is found from the NQR observables. On the contrary, the low-energy dynamics is dominated by anisotropic spin fluctuations with strong, nearly critical, in-plane character, which are effectively identical to the case of the sister compound PuCoIn 5. Lastly, these findings are discussed within the context of different theoretical proposals for the unconventional pairing mechanism in heavy-fermion superconductors.« less

Authentication Sensing System Using Resonance Evaluation Spectroscopy (ASSURES)

NASA Astrophysics Data System (ADS)

Trolinger, James D.; Dioumaev, Andrei K.; Lal, Amit K.; Dimas, Dave

2017-08-01

This paper describes an ongoing instrument development project to distinguish genuine manufactured components from counterfeit components; we call the instrument ASSURES (Authentication Sensing System Using Resonance Evaluation Spectroscopy). The system combines Laser Doppler Vibrometry with acoustical resonance spectroscopy, augmented with finite element analysis. Vibrational properties of components, such as resonant modes, damping, and spectral frequency response to various forcing functions depend strongly upon the mechanical properties of the material, including its size, shape, internal hardness, tensile strength, alloy/composite compositions, flaws, defects, and other internal material properties. Although acoustic resonant spectroscopy has seen limited application, the information rich signals in the vibrational spectra of objects provide a pathway to many new applications. Components with the same shape but made of different materials, different fatigue histories, damage, tampering, or heat treatment, will respond differently to high frequency stimulation. Laser Doppler Vibrometry offers high sensitivity and frequency bandwidth to measure the component's frequency spectrum, and overcomes many issues that limit conventional acoustical resonance spectroscopy, since the sensor laser beam can be aimed anywhere along the part as well as to multiple locations on a part in a non-contact way. ASSURES is especially promising for use in additive manufacturing technology by providing signatures as digital codes that are unique to specific objects and even to specific locations on objects. We believe that such signatures can be employed to address many important issues in the manufacturing industry. These include insuring the part meets the often very rigid specifications of the customer and being able to detect non-visible internal manufacturing defects or non-visible damage that has occurred after manufacturing.

Hybrid quadrupole mass filter/quadrupole ion trap/time-of-flight-mass spectrometer for infrared multiple photon dissociation spectroscopy of mass-selected ions

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

Gulyuz, Kerim; Stedwell, Corey N.; Wang Da

2011-05-15

We present a laboratory-constructed mass spectrometer optimized for recording infrared multiple photon dissociation (IRMPD) spectra of mass-selected ions using a benchtop tunable infrared optical parametric oscillator/amplifier (OPO/A). The instrument is equipped with two ionization sources, an electrospray ionization source, as well as an electron ionization source for troubleshooting. This hybrid mass spectrometer is composed of a quadrupole mass filter for mass selection, a reduced pressure ({approx}10{sup -5} Torr) quadrupole ion trap (QIT) for OPO irradiation, and a reflectron time-of-flight drift tube for detecting the remaining precursor and photofragment ions. A helium gas pulse is introduced into the QIT to temporarilymore » increase the pressure and hence enhance the trapping efficiency of axially injected ions. After a brief pump-down delay, the compact ion cloud is subjected to the focused output from the continuous wave OPO. In a recent study, we implemented this setup in the study of protonated tryptophan, TrpH{sup +}, as well as collision-induced dissociation products of this protonated amino acid [W. K. Mino, Jr., K. Gulyuz, D. Wang, C. N. Stedwell, and N. C. Polfer, J. Phys. Chem. Lett. 2, 299 (2011)]. Here, we give a more detailed account on the figures of merit of such IRMPD experiments. The appreciable photodissociation yields in these measurements demonstrate that IRMPD spectroscopy of covalently bound ions can be routinely carried out using benchtop OPO setups.« less

Scanning micro-resonator direct-comb absolute spectroscopy

PubMed Central

Gambetta, Alessio; Cassinerio, Marco; Gatti, Davide; Laporta, Paolo; Galzerano, Gianluca

2016-01-01

Direct optical Frequency Comb Spectroscopy (DFCS) is proving to be a fundamental tool in many areas of science and technology thanks to its unique performance in terms of ultra-broadband, high-speed detection and frequency accuracy, allowing for high-fidelity mapping of atomic and molecular energy structure. Here we present a novel DFCS approach based on a scanning Fabry-Pérot micro-cavity resonator (SMART) providing a simple, compact and accurate method to resolve the mode structure of an optical frequency comb. The SMART approach, while drastically reducing system complexity, allows for a straightforward absolute calibration of the optical-frequency axis with an ultimate resolution limited by the micro-resonator resonance linewidth and can be used in any spectral region from UV to THz. We present an application to high-precision spectroscopy of acetylene at 1.54 μm, demonstrating performances comparable or even better than current state-of-the-art DFCS systems in terms of sensitivity, optical bandwidth and frequency-resolution. PMID:27752132

A study of the semiconductor compound СuAlO2 by the method of nuclear quadrupole resonance of Cu

NASA Astrophysics Data System (ADS)

Matukhin, V. L.; Khabibulin, I. Kh.; Shul'gin, D. A.; Smidt, S. V.

2012-07-01

The method of nuclear quadrupole resonance of Cu (NQR Cu) is used to study the samples of a semiconductor compound CuAlO2. The crystal structure of CuAlO2 belongs to the family of delafossite - the mineral of a basic CuFeO2 structure. Transparent semiconductor oxides, such as CuAlO2, have attracted recent attention as promising thermoelectric materials.

A microwave resonator for limiting depth sensitivity for electron paramagnetic resonance spectroscopy of surfaces.

PubMed

Sidabras, Jason W; Varanasi, Shiv K; Mett, Richard R; Swarts, Steven G; Swartz, Harold M; Hyde, James S

2014-10-01

A microwave Surface Resonator Array (SRA) structure is described for use in Electron Paramagnetic Resonance (EPR) spectroscopy. The SRA has a series of anti-parallel transmission line modes that provides a region of sensitivity equal to the cross-sectional area times its depth sensitivity, which is approximately half the distance between the transmission line centers. It is shown that the quarter-wave twin-lead transmission line can be a useful element for design of microwave resonators at frequencies as high as 10 GHz. The SRA geometry is presented as a novel resonator for use in surface spectroscopy where the region of interest is either surrounded by lossy material, or the spectroscopist wishes to minimize signal from surrounding materials. One such application is in vivo spectroscopy of human finger-nails at X-band (9.5 GHz) to measure ionizing radiation dosages. In order to reduce losses associated with tissues beneath the nail that yield no EPR signal, the SRA structure is designed to limit depth sensitivity to the thickness of the fingernail. Another application, due to the resonator geometry and limited depth penetration, is surface spectroscopy in coating or material science. To test this application, a spectrum of 1.44 μM of Mg(2+) doped polystyrene 1.1 mm thick on an aluminum surface is obtained. Modeling, design, and simulations were performed using Wolfram Mathematica (Champaign, IL; v. 9.0) and Ansys High Frequency Structure Simulator (HFSS; Canonsburg, PA; v. 15.0). A micro-strip coupling circuit is designed to suppress unwanted modes and provide a balanced impedance transformation to a 50 Ω coaxial input. Agreement between simulated and experimental results is shown.

A microwave resonator for limiting depth sensitivity for electron paramagnetic resonance spectroscopy of surfaces

PubMed Central

Sidabras, Jason W.; Varanasi, Shiv K.; Mett, Richard R.; Swarts, Steven G.; Swartz, Harold M.; Hyde, James S.

2014-01-01

A microwave Surface Resonator Array (SRA) structure is described for use in Electron Paramagnetic Resonance (EPR) spectroscopy. The SRA has a series of anti-parallel transmission line modes that provides a region of sensitivity equal to the cross-sectional area times its depth sensitivity, which is approximately half the distance between the transmission line centers. It is shown that the quarter-wave twin-lead transmission line can be a useful element for design of microwave resonators at frequencies as high as 10 GHz. The SRA geometry is presented as a novel resonator for use in surface spectroscopy where the region of interest is either surrounded by lossy material, or the spectroscopist wishes to minimize signal from surrounding materials. One such application is in vivo spectroscopy of human finger-nails at X-band (9.5 GHz) to measure ionizing radiation dosages. In order to reduce losses associated with tissues beneath the nail that yield no EPR signal, the SRA structure is designed to limit depth sensitivity to the thickness of the fingernail. Another application, due to the resonator geometry and limited depth penetration, is surface spectroscopy in coating or material science. To test this application, a spectrum of 1.44 μM of Mg2+ doped polystyrene 1.1 mm thick on an aluminum surface is obtained. Modeling, design, and simulations were performed using Wolfram Mathematica (Champaign, IL; v. 9.0) and Ansys High Frequency Structure Simulator (HFSS; Canonsburg, PA; v. 15.0). A micro-strip coupling circuit is designed to suppress unwanted modes and provide a balanced impedance transformation to a 50 Ω coaxial input. Agreement between simulated and experimental results is shown. PMID:25362434

A microwave resonator for limiting depth sensitivity for electron paramagnetic resonance spectroscopy of surfaces

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

Sidabras, Jason W.; Varanasi, Shiv K.; Hyde, James S.

2014-10-15

A microwave Surface Resonator Array (SRA) structure is described for use in Electron Paramagnetic Resonance (EPR) spectroscopy. The SRA has a series of anti-parallel transmission line modes that provides a region of sensitivity equal to the cross-sectional area times its depth sensitivity, which is approximately half the distance between the transmission line centers. It is shown that the quarter-wave twin-lead transmission line can be a useful element for design of microwave resonators at frequencies as high as 10 GHz. The SRA geometry is presented as a novel resonator for use in surface spectroscopy where the region of interest is eithermore » surrounded by lossy material, or the spectroscopist wishes to minimize signal from surrounding materials. One such application is in vivo spectroscopy of human finger-nails at X-band (9.5 GHz) to measure ionizing radiation dosages. In order to reduce losses associated with tissues beneath the nail that yield no EPR signal, the SRA structure is designed to limit depth sensitivity to the thickness of the fingernail. Another application, due to the resonator geometry and limited depth penetration, is surface spectroscopy in coating or material science. To test this application, a spectrum of 1.44 μM of Mg{sup 2+} doped polystyrene 1.1 mm thick on an aluminum surface is obtained. Modeling, design, and simulations were performed using Wolfram Mathematica (Champaign, IL; v. 9.0) and Ansys High Frequency Structure Simulator (HFSS; Canonsburg, PA; v. 15.0). A micro-strip coupling circuit is designed to suppress unwanted modes and provide a balanced impedance transformation to a 50 Ω coaxial input. Agreement between simulated and experimental results is shown.« less

Dependence of nuclear quadrupole resonance transitions on the electric field gradient asymmetry parameter for nuclides with half-integer spins

DOE PAGES

Cho, Herman

2016-02-28

Allowed transition energies and eigenstate expansions have been calculated and tabulated in numerical form as functions of the electric field gradient asymmetry parameter for the zero field Hamiltonian of quadrupolar nuclides with I = 3/2,5/2,7/2, and 9/2. These results are essential to interpret nuclear quadrupole resonance (NQR) spectra and extract accurate values of the electric field gradient tensors. Furthermore, applications of NQR methods to studies of electronic structure in heavy element systems are proposed.

Interpretive Experiments: An Interpretive Experiment in Ion Cyclotron Resonance Spectroscopy.

ERIC Educational Resources Information Center

Burnier, R. C.; Freiser, B. S.

1979-01-01

Provides a discussion which is intended for chemistry college students on the ion cyclotron resonance (ICR) spectroscopy, the physical basis for ion cyclotron resonance, and the experimental methodology employed by ICR spectroscopists. (HM)

Near-Field Spectroscopy and Imaging of Subwavelength Plasmonic Terahertz Resonators

DOE PAGES

Mitrofanov, Oleg; Khromova, Irina; Siday, Thomas; ...

2016-04-22

We describe the temporal evolution of the terahertz (THz) field leading to the excitation of plasmonic resonances in carbon microfibers. The field evolution is mapped in space and time for the 3/2 wavelength resonance using a subwavelength aperture THz near-field probe with an embedded THz photoconductive detector. The excitation of surface waves at the fiber tips leads to the formation of a standing wave along the fiber. Local THz time-domain spectroscopy at one of the standing wave crests shows a clear third-order resonance peak at 1.65 THz, well described by the Lorentz model. Lastly, this application of the subwavelength aperturemore » THz near-field microscopy for mode mapping and local spectroscopy demonstrates the potential of near-field methods for studies of subwavelength plasmonic THz resonators.« less

Laser resonance ionization spectroscopy of antimony

NASA Astrophysics Data System (ADS)

Li, R.; Lassen, J.; Ruczkowski, J.; Teigelhöfer, A.; Bricault, P.

2017-02-01

The resonant ionization laser ion source is an element selective, efficient and versatile ion source to generate radioactive ion beams at on-line mass separator facilities. For some elements with complex atomic structures and incomplete spectroscopic data, laser spectroscopic investigations are required for ionization scheme development. Laser resonance ionization spectroscopy using Ti:Sa lasers has been performed on antimony (Sb) at TRIUMF's off-line laser ion source test stand. Laser light of 230.217 nm (vacuum wavelength) as the first excitation step and light from a frequency-doubled Nd:YVO4 laser (532 nm) as the nonresonant ionization step allowed to search for suitable second excitation steps by continuous wavelength scans from 720 nm to 920 nm across the wavelength tuning range of a grating-tuned Ti:Sa laser. Upon the identification of efficient SES, the third excitation steps for resonance ionization were investigated by laser scans across Rydberg states, the ionization potential and autoionizing states. One Rydberg state and six AI states were found to be well suitable for efficient resonance ionization.

Surface plasmon resonance near-infrared spectroscopy.

PubMed

Ikehata, Akifumi; Itoh, Tamitake; Ozaki, Yukihiro

2004-11-01

Near-infrared (NIR) spectroscopy is ill-suited to microanalysis because of its low absorptivity. We have developed a highly sensitive detection method for NIR spectroscopy based on absorption-sensitive surface plasmon resonance (SPR). The newly named SPR-NIR spectroscopy, which may open the way for NIR spectroscopy in microanalysis and surface science, is realized by an attachment of the Kretschmann configuration equipped with a mechanism for fine angular adjustment of incident light. The angular sweep of incident light enables us to make a tuning of a SPR peak for an absorption band of sample medium. From the dependences of wavelength, incident angle, and thickness of a gold film on the intensity of the SPR peak, it has been found that the absorbance can be enhanced by approximately 100 times compared with the absorbance obtained without the gold film under optimum conditions. This article reports the details of the experimental setup and the characteristics of absorption-sensitive SPR in the NIR region, together with some experimental results obtained by using it.

Periodontitis diagnostics using resonance Raman spectroscopy on saliva

NASA Astrophysics Data System (ADS)

Gonchukov, S.; Sukhinina, A.; Bakhmutov, D.; Biryukova, T.; Tsvetkov, M.; Bagratashvily, V.

2013-07-01

In view of its wealth of molecular information, Raman spectroscopy has been the subject of active biomedical research. The aim of this work is Raman spectroscopy (RS) application for the determination of molecular biomarkers in saliva with the objective of early periodontitis detection. As was shown in our previous study, carotenoids contained in saliva can be molecular fingerprint information for the periodontitis level. It is shown here that the carotenoid RS lines at wavenumbers of 1156 and 1524 cm-1 can be easily detected and serve as reliable biomarkers of periodontitis using resonance Raman spectroscopy of dry saliva.

[Phosphorus magnetic resonance spectroscopy: Brain pathologies applications].

PubMed

Menuel, C; Guillevin, R; Costalat, R; Perrin, M; Sahli-Amor, M; Martin-Duverneuil, N; Chiras, J

2010-05-01

Until recent years, brain applications of (31)P magnetic resonance spectroscopy were poor. Arising of clinical high field strength magnets (three Tesla) as well as dedicated brain coils (eg: bird cage), using specific and useful sequences providing appropriate spatial localisation and signal to noise ratio brought highlights on multinuclear spectroscopy. Better understanding of brain metabolism emphasizes the role of phosphoenergetic compounds and its potential issues in tumoral, metabolic and degenerative diseases. In the present paper, we report 1 year of experience and preliminary results for 40 patients as well as review of the literature. By successive in vivo determination and quantitation of numerous metabolites it allows, multinuclear spectroscopy may provide additional information to biomathematical models of brain metabolism. Copyright 2009. Published by Elsevier Masson SAS.

Frequency shifts in gravitational resonance spectroscopy

DOE PAGES

Baeßler, S.; Nesvizhevsky, V. V.; Pignol, G.; ...

2015-02-25

Quantum states of ultracold neutrons in a gravitational field are characterized through gravitational resonance spectroscopy. This paper discusses systematic effects that appear in the spectroscopic measurements. The discussed frequency shifts-which we call the Stern-Gerlach shift, interference shift, and spectator-state shift-appear in conceivable measurement schemes and have general importance. Lastly, these shifts have to be taken into account in precision experiments.

Axially uniform resonant cavity modes for potential use in electron paramagnetic resonance spectroscopy

NASA Astrophysics Data System (ADS)

Mett, Richard R.; Froncisz, Wojciech; Hyde, James S.

2001-11-01

This article is concerned with cylindrical transverse electric TE011 and rectangular TE102 microwave cavity resonators commonly used in electron paramagnetic resonance (EPR) spectroscopy. In the cylindrical mode geometry considered here, the sample is along the z axis of the cylinder, dielectric disks of 1/4 wavelength thickness are placed at each end wall, and the diameter of the cylinder is set at the cutoff condition for propagation of microwave energy in a cylindrical waveguide at the desired microwave frequency. The microwave magnetic field is exactly uniform along the sample in the region between the dielectric disks and the resonant frequency is independent of the length of the cylinder without limit. The rectangular TE102 geometry is analogous, but here the microwave magnetic field is exactly uniform in a plane. A uniform microwave field along a line sample is highly advantageous in EPR spectroscopy compared with the usual sinusoidal variation, and these geometries are called "uniform field" modes. Extensive theoretical analysis as well as finite element calculation of field patterns are presented. The perturbation of field patterns caused by sample insertion as functions of the overall length of the resonator and diameter of the sample is analyzed. The article is intended to provide a basis for design of practical structures in the range of 10 to 100 GHz.

The129I hyperfine interaction in fatty acids studied by Mössbauer spectroscopy

NASA Astrophysics Data System (ADS)

Burda, K.; Strzałka, K.; Stanek, J.

1993-12-01

Oleic acid substituted by iodine and saponified by Ca2+ cations has been studied by129I Mössbauer spectroscopy. The quadrupole coupling constants and isomer shifts, determined from the γ-resonance spectra recorded at 4.2 K, have been described by 5p and 5s orbital populations of iodine. It was also found that saponification of the fatty acid has no significant influence on the measured iodine bonds. However, the increased order of fatty acids in soap form is reflected by narrowing of the resonant linewidth due to the reduction of the electric field gradient distribution.

Imaging Intelligence with Proton Magnetic Resonance Spectroscopy

ERIC Educational Resources Information Center

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

2009-01-01

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

Laser-spectroscopy studies of the nuclear structure of neutron-rich radium

NASA Astrophysics Data System (ADS)

Lynch, K. M.; Wilkins, S. G.; Billowes, J.; Binnersley, C. L.; Bissell, M. L.; Chrysalidis, K.; Cocolios, T. E.; Goodacre, T. Day; de Groote, R. P.; Farooq-Smith, G. J.; Fedorov, D. V.; Fedosseev, V. N.; Flanagan, K. T.; Franchoo, S.; Garcia Ruiz, R. F.; Gins, W.; Heinke, R.; Koszorús, Á.; Marsh, B. A.; Molkanov, P. L.; Naubereit, P.; Neyens, G.; Ricketts, C. M.; Rothe, S.; Seiffert, C.; Seliverstov, M. D.; Stroke, H. H.; Studer, D.; Vernon, A. R.; Wendt, K. D. A.; Yang, X. F.

2018-02-01

The neutron-rich radium isotopes, Ra-233222, were measured with Collinear Resonance Ionization Spectroscopy (CRIS) at the ISOLDE facility, CERN. The hyperfine structure of the 7 s2S10→7 s 7 p P31 transition was probed, allowing measurement of the magnetic moments, quadrupole moments, and changes in mean-square charge radii. These results are compared to existing literature values, and the new moments and change in mean-square charge radii of 231Ra are presented. Low-resolution laser spectroscopy of the very neutron-rich 233Ra has allowed the isotope shift and relative charge radius to be determined for the first time.

Magnetic resonance spectroscopy of the human brain

NASA Astrophysics Data System (ADS)

Strózik-Kotlorz, D.

2014-01-01

I give a brief description of the magnetic resonance spectroscopy (MRS) in the human brain examinations. MRS allows a noninvasive chemical analysis of the brain using a standard high field MR system. Nowadays, the dominant form of MR brain spectroscopy is proton spectroscopy. Two main techniques of MRS, which utilize the chemical shift of metabolites in the external magnetic field, are SVS (single voxel) and CSI (single slice). The major peaks in the spectrum of a normal brain include NAA, Cr, Cho and m-Ins, which are neuronal, energetic, membrane turnover and glial markers, respectively. In disease, two pathological metabolites can be found in the brain spectra: Lac, which is end product of anaerobic glycolysis and Lip, which is a marker of membrane breakdown, occurring in necrosis. The common way to analyze clinical spectra is to determine metabolite ratios, e.g. NAA/Cr, Cho/Cr, Cho/NAA. This analysis permits a safe and noninvasive examination of the brain tissue as each disease state has its own characteristic spectroscopic image. MRS is a valuable diagnostic tool in such clinical applications as detecting brain tumors and differentiating tumors from inflammatory and infectious processes. Proton MRS is also very helpful in diagnostic of ischemic lesions, Alzheimer's disease and hepatic encephalopathy. The MRS brain spectra should always be correlated with the Magnetic Resonance Imaging (MRI) results and alone cannot make neurological diagnosis.

Stand-off detection of vapor phase explosives by resonance enhanced Raman spectroscopy

NASA Astrophysics Data System (ADS)

Ehlerding, Anneli; Johansson, Ida; Wallin, Sara; Östmark, Henric

2010-10-01

Stand-off measurements on nitromethane (NM), 2,4-DNT and 2,4,6-TNT in vapor phase using resonance Raman spectroscopy have been performed. The Raman cross sections for NM, DNT and TNT in vapor phase have been measured in the wavelength range 210-300 nm under laboratory conditions, in order to estimate how large resonance enhancement factors can be achieved for these explosives. The measurements show that the signal is greatly enhanced, up to 250.000 times for 2,4-DNT and 60.000 times for 2,4,6-TNT compared to the non-resonant signal at 532 nm. For NM the resonance enhancement enabled realistic outdoor measurements in vapor phase at 13 m distance. This all indicate a potential for resonance Raman spectroscopy as a stand-off technique for detection of vapor phase explosives.

Electric field gradient in FeTiO3 by nuclear magnetic resonance and ab initio calculations.

PubMed

Procházka, V; Stěpánková, H; Chlan, V; Tuček, J; Cuda, J; Kouřil, K; Filip, J; Zbořil, R

2011-05-25

Temperature dependence of nuclear magnetic resonance (NMR) spectra of (47)Ti and (49)Ti in polycrystalline ilmenite FeTiO(3) was measured in the range from 5 to 300 K under an external magnetic field of 9.401 T. NMR spectra collected between 300 and 77 K exhibit a resolved quadrupole splitting. The electric field gradient (EFG) tensor was evaluated for Ti nuclei and the ratio of (47)Ti and (49)Ti nuclear quadrupole moments was refined during the fitting procedure. Below 77 K, the fine structure of quadrupole splitting disappears due to the enormous increase of anisotropy. As a counterpart, ab initio calculations were performed using full potential augmented plane waves + local orbitals. The calculated EFG tensors for Ti and Fe were compared to the experimental ones evaluated from NMR and the Mössbauer spectroscopy experiments.

Quantitative structure parameters from the NMR spectroscopy of quadrupolar nuclei

DOE PAGES

Perras, Frederic A.

2015-12-15

Here, nuclear magnetic resonance (NMR) spectroscopy is one of the most important characterization tools in chemistry, however, 3/4 of the NMR active nuclei are underutilized due to their quadrupolar nature. This short review centers on the development of methods that use solid-state NMR of quadrupolar nuclei for obtaining quantitative structural information. Namely, techniques using dipolar recoupling as well as the resolution afforded by double-rotation are presented for the measurement of spin–spin coupling between quadrupoles, enabling the measurement of internuclear distances and connectivities.

Proton magnetic resonance spectroscopy of tubercular breast abscess: report of a case.

PubMed

Das, Chandan Jyoti; Medhi, Kunjahari

2008-01-01

In vivo proton magnetic resonance spectroscopy (H-MRS) is a functional imaging modality. When magnetic resonance imaging is coupled with H-MRS, it results in accurate metabolic characterization of various lesions. Proton magnetic resonance spectroscopy has an established role in evaluating malignant breast lesions, and the increasing number of published literature supports the role of H-MRS in patients with breast cancer. However, H-MRS can be of help in evaluating benign breast disease. We present a case of tubercular breast abscess, initial diagnosis of which was suggested based on characteristic lipid pick on H-MRS and was subsequently confirmed by fine needle aspiration biopsy of the breast lesion.

Detection of Nitric Oxide by Electron Paramagnetic Resonance Spectroscopy

PubMed Central

Hogg, Neil

2010-01-01

Electron paramagnetic resonance (EPR) spectroscopy has been used in a number of ways to study nitric oxide chemistry and biology. As an intrinsically stable and relatively unreactive diatomic free radical, the challenges for detecting this species by EPR are somewhat different than those for transient radical species. This review gives a basic introduction to EPR spectroscopy and discusses its uses to assess and quantify nitric oxide formation in biological systems. PMID:20304044

Characterization of a Continuous Wave Laser for Resonance Ionization Mass Spectroscopy Analysis in Nuclear Forensics

DTIC Science & Technology

2015-06-01

OF A CONTINUOUS WAVE LASER FOR RESONANCE IONIZATION MASS SPECTROSCOPY ANALYSIS IN NUCLEAR FORENSICS by Sunny G. Lau June 2015 Thesis...IONIZATION MASS SPECTROSCOPY ANALYSIS IN NUCLEAR FORENSICS 5. FUNDING NUMBERS 6. AUTHOR(S) Sunny G. Lau 7. PERFORMING ORGANIZATION NAME(S) AND...200 words) The application of resonance ionization mass spectroscopy (RIMS) to nuclear forensics involves the use of lasers to selectively ionize

Dependence of nuclear quadrupole resonance transitions on the electric field gradient asymmetry parameter for nuclides with half-integer spins

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

Cho, Herman

2016-09-01

Allowed transition energies and eigenstate expansions have been calculated and tabulated in numerical form as functions of the electric field gradient asymmetry parameter for the zero field Hamiltonian of quadrupolar nuclides with I = 3/2, 5/2, 7/2, and 9/2. These results may be used to interpret nuclear quadrupole resonance (NQR) spectra and extract accurate values of the electric field gradient tensors. Applications of NQR methods to studies of electronic structure in heavy element systems are proposed. This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences, Heavy Element Chemistrymore » program.« less

Ultrasonic Resonance Spectroscopy of Composite Rings for Flywheel Rotors

NASA Technical Reports Server (NTRS)

Harmon, Laura M.; Baaklini, George Y.

2001-01-01

Flywheel energy storage devices comprising multilayered composite rotor systems are being studied extensively for utilization in the International Space Station. These composite material systems were investigated with a recently developed ultrasonic resonance spectroscopy technique. The system employs a swept frequency approach and performs a fast Fourier transform on the frequency spectrum of the response signal. In addition. the system allows for equalization of the frequency spectrum, providing all frequencies with equal amounts of energy to excite higher order resonant harmonics. Interpretation of the second fast Fourier transform, along with equalization of the frequency spectrum, offers greater assurance in acquiring and analyzing the fundamental frequency, or spectrum resonance spacing. The range of frequencies swept in a pitch-catch mode was varied up to 8 MHz, depending on the material and geometry of the component. Single and multilayered material samples, with and without known defects, were evaluated to determine how the constituents of a composite material system affect the resonant frequency. Amplitude and frequency changes in the spectrum and spectrum resonance spacing domains were examined from ultrasonic responses of a flat composite coupon, thin composite rings, and thick composite rings. Also, the ultrasonic spectroscopy responses from areas with an intentional delamination and a foreign material insert, similar to defects that may occur during manufacturing malfunctions, were compared with those from defect-free areas in thin composite rings. A thick composite ring with varying thickness was tested to investigate the full-thickness resonant frequency and any possible bulk interfacial bond issues. Finally, the effect on the frequency response of naturally occurring single and clustered voids in a composite ring was established.

SNS Resonance Control Cooling Systems and Quadrupole Magnet Cooling Systems DIW Chemistry

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

Magda, Karoly

This report focuses on control of the water chemistry for the Spallation Neutron Source (SNS) Resonance Control Cooling System (RCCS)/Quadrupole Magnet Cooling System (QMCS) deionized water (DIW) cooling loops. Data collected from spring 2013 through spring 2016 are discussed, and an operations regime is recommended.It was found that the RCCS operates with an average pH of 7.24 for all lines (from 7.0 to 7.5, slightly alkaline), the average low dissolved oxygen is in the area of < 36 ppb, and the main loop average resistivity of is > 14 MΩ-cm. The QMCS was found to be operating in a similarmore » regime, with a slightly alkaline pH of 7.5 , low dissolved oxygen in the area of < 45 ppb, and main loop resistivity of 10 to 15 MΩ-cm. During data reading, operational corrections were done on the polishing loops to improve the water chemistry regime. Therefore some trends changed over time.It is recommended that the cooling loops operate in a regime in which the water has a resistivity that is as high as achievable, a dissolved oxygen concentration that is as low as achievable, and a neutral or slightly alkaline pH.« less

Optimization of 31P magnetic resonance spectroscopy in vivo

NASA Astrophysics Data System (ADS)

Manzhurtsev, A. V.; Akhadov, T. A.; Semenova, N. A.

2018-01-01

The main problem of magnetic resonance spectroscopy on phosphorus nuclei (31P MRS) is low signal-to-noise ratio (SNR) of spectra acquired on clinical (3T) scanners. This makes quantitative processing of spectra difficult. The optimization of method on a single-voxel model reported in current work implicates an impact of the spin-lattice (T1) relaxation on SNR, and also evaluates the effectiveness of Image Selected InVivo Spectroscopy (ISIS) pulse sequence modification for the increase of SNR.

Elucidation of chemical reactions by two-dimensional resonance Raman spectroscopy

NASA Astrophysics Data System (ADS)

Molesky, Brian Paul

It has been shown for many systems, including photosynthetic complexes, molecule-semiconductor interfaces, and bulk heterojunctions, that interaction between electronic and nuclear dynamics may heavily influence chemical mechanisms. Four-wave-mixing spectroscopies (i.e. transient absorption, two-dimensional spectroscopy) provide some insight into such non-equilibrium processes but are limited by the single "population time" available in these types of experiments. In this dissertation, two-dimensional resonance Raman spectroscopy (2DRR) is developed to obtain new information regarding chemical reactions that possess time coincident electronic and nuclear evolution. These new insights can only be acquired through higher-order techniques possessing two "population times". Specifically, the coherent reaction mechanism in triiodide photodissociation and structural heterogeneity in myoglobin are investigated. All multidimensional spectroscopies have roots in the off-resonant multidimensional Raman techniques developed from the late 1980's to the early 2000's. Throughout their development these experiments were plagued with technical challenges that eventually halted further use. In this dissertation it is shown through rigorous experimental tests that the technical challenges of the past are obviated for 2DRR, which is done under electronically resonant conditions. The key is that under electronic resonance the harmonic character of vibrational modes contributes to the signal. Under off-resonant conditions signal generation depends on much weaker effects. Upon absorption of light ranging from 250 to 500 nm triiodide photodissociates into diiodide and radical iodine on the same time scale as the period of triiodide's symmetric stretch, impulsively initiating coherence in the stretching coordinate of diiodide. In this dissertation, the sensitivity of 2DRR to coherent reaction mechanisms is shown by directly measuring, for the first time, how the nonequilibrium geometry of

Solution nuclear magnetic resonance spectroscopy on a nanostructured diamond chip.

PubMed

Kehayias, P; Jarmola, A; Mosavian, N; Fescenko, I; Benito, F M; Laraoui, A; Smits, J; Bougas, L; Budker, D; Neumann, A; Brueck, S R J; Acosta, V M

2017-08-04

Sensors using nitrogen-vacancy centers in diamond are a promising tool for small-volume nuclear magnetic resonance (NMR) spectroscopy, but the limited sensitivity remains a challenge. Here we show nearly two orders of magnitude improvement in concentration sensitivity over previous nitrogen-vacancy and picoliter NMR studies. We demonstrate NMR spectroscopy of picoliter-volume solutions using a nanostructured diamond chip with dense, high-aspect-ratio nanogratings, enhancing the surface area by 15 times. The nanograting sidewalls are doped with nitrogen-vacancies located a few nanometers from the diamond surface to detect the NMR spectrum of roughly 1 pl of fluid lying within adjacent nanograting grooves. We perform 1 H and 19 F nuclear magnetic resonance spectroscopy at room temperature in magnetic fields below 50 mT. Using a solution of CsF in glycerol, we determine that 4 ± 2 × 10 12 19 F spins in a 1 pl volume can be detected with a signal-to-noise ratio of 3 in 1 s of integration.Nitrogen vacancy (NV) centres in diamond can be used for NMR spectroscopy, but increased sensitivity is needed to avoid long measurement times. Kehayias et al. present a nanostructured diamond grating with a high density of NV centres, enabling NMR spectroscopy of picoliter-volume solutions.

Weak quadrupole moments

NASA Astrophysics Data System (ADS)

Lackenby, B. G. C.; Flambaum, V. V.

2018-07-01

We introduce the weak quadrupole moment (WQM) of nuclei, related to the quadrupole distribution of the weak charge in the nucleus. The WQM produces a tensor weak interaction between the nucleus and electrons and can be observed in atomic and molecular experiments measuring parity nonconservation. The dominating contribution to the weak quadrupole is given by the quadrupole moment of the neutron distribution, therefore, corresponding experiments should allow one to measure the neutron quadrupoles. Using the deformed oscillator model and the Schmidt model we calculate the quadrupole distributions of neutrons, Q n , the WQMs, {Q}W(2), and the Lorentz invariance violating energy shifts in 9Be, 21Ne, 27Al, 131Xe, 133Cs, 151Eu, 153Eu, 163Dy, 167Er, 173Yb, 177Hf, 179Hf, 181Ta, 201Hg and 229Th.

Mesoscopic Magnetic Resonance Spectroscopy with a Remote Spin Sensor

NASA Astrophysics Data System (ADS)

Xie, Tianyu; Shi, Fazhan; Chen, Sanyou; Guo, Maosen; Chen, Yisheng; Zhang, Yixing; Yang, Yu; Gao, Xingyu; Kong, Xi; Wang, Pengfei; Tateishi, Kenichiro; Uesaka, Tomohiro; Wang, Ya; Zhang, Bo; Du, Jiangfeng

2018-06-01

Quantum sensing based on nitrogen-vacancy (N -V ) centers in diamond has been developed as a powerful tool for microscopic magnetic resonance. However, the reported sensor-to-sample distance is limited within tens of nanometers resulting from the cubic decrease of the signal of spin fluctuation with the increasing distance. Here we extend the sensing distance to tens of micrometers by detecting spin polarization rather than spin fluctuation. We detect the mesoscopic magnetic resonance spectra of polarized electrons of a pentacene-doped crystal, measure its two typical decay times, and observe the optically enhanced spin polarization. This work paves the way for the N -V -based mesoscopic magnetic resonance spectroscopy and imaging at ambient conditions.

Spin noise spectroscopy of rubidium atomic gas under resonant and non-resonant conditions

NASA Astrophysics Data System (ADS)

Ma, Jian; Shi, Ping; Qian, Xuan; Li, Wei; Ji, Yang

2016-11-01

The spin fluctuation in rubidium atom gas is studied via all-optical spin noise spectroscopy (SNS). Experimental results show that the integrated SNS signal and its full width at half maximum (FWHM) strongly depend on the frequency detuning of the probe light under resonant and non-resonant conditions. The total integrated SNS signal can be well fitted with a single squared Faraday rotation spectrum and the FWHM dependence may be related to the absorption profile of the sample. Project supported by the National Natural Science Foundation of China (Grant Nos. 91321310 and 11404325) and the National Basic Research Program of China (Grant No. 2013CB922304).

Multiple-step relayed correlation spectroscopy: sequential resonance assignments in oligosaccharides.

PubMed Central

Homans, S W; Dwek, R A; Fernandes, D L; Rademacher, T W

1984-01-01

A general property of the high-resolution proton NMR spectra of oligosaccharides is the appearance of low-field well-resolved resonances corresponding to the anomeric (H1) and H2 protons. The remaining skeletal protons resonate in the region 3-4 ppm, giving rise to an envelope of poorly resolved resonances. Assignments can be made from the H1 and H2 protons to their J-coupled neighbors (H2 and H3) within this main envelope by using 1H-1H correlated spectroscopy. However, the tight coupling (J congruent to delta) between further protons results in poor spectral dispersion with consequent assignment ambiguities. We describe here three-step two-dimensional relayed correlation spectroscopy and show how it can be used to correlate the resolved anomeric (H1) and H2 protons with remote (H4, H5) protons directly through a linear network of couplings using sequential magnetization transfer around the oligosaccharide rings. Resonance assignments are then obtained by inspection of cross-peaks that appear in well-resolved regions of the two-dimensional spectrum. This offers a general solution to the assignment problem in oligosaccharides and, importantly, these assignments will subsequently allow for the three-dimensional solution conformation to be determined by using one-dimensional and two-dimensional nuclear Overhauser experiments. PMID:6593701

Microscopic evidence for magnetic ordering in NdCu3Ru4O12 : 63,65Cu nuclear quadrupole resonance study

NASA Astrophysics Data System (ADS)

Yogi, M.; Niki, H.; Hedo, M.; Komesu, S.; Nakama, T.

2018-05-01

We have conducted 63,65Cu nuclear quadrupole resonance (NQR) measurements on A-site ordered perovskite compounds LaCu3Ru4O12 and NdCu3Ru4O12 to investigate their ground state and spin fluctuations. While there is only one Cu site in the crystal structure, multiple NQR resonance lines were observed. This is presumed to be due to the presence of slight distortion and lattice defects in the samples. The nuclear spin-lattice relaxation rate divided by temperature, 1 /T1 T , for LaCu3Ru4O12 showed almost constant value indicating the Fermi-liquid state. A remarkable increase in 1 /T1 T due to spin fluctuations was observed in NdCu3Ru4O12 . Furthermore, an evident magnetic phase transition at TM = 0.6 K was revealed from the distinct peak of 1 /T1 T and the broadening of the NQR spectrum.

Ultraviolet resonance Raman spectroscopy for the detection of cocaine in oral fluid

NASA Astrophysics Data System (ADS)

D'Elia, Valentina; Montalvo, Gemma; Ruiz, Carmen García; Ermolenkov, Vladimir V.; Ahmed, Yasmine; Lednev, Igor K.

2018-01-01

Detecting and quantifying cocaine in oral fluid is of significant importance for practical forensics. Up to date, mainly destructive methods or biochemical tests have been used, while spectroscopic methods were only applied to pretreated samples. In this work, the possibility of using resonance Raman spectroscopy to detect cocaine in oral fluid without pretreating samples was tested. It was found that ultraviolet resonance Raman spectroscopy with 239-nm excitation allows for the detection of cocaine in oral fluid at 10 μg/mL level. Further method development will be needed for reaching the practically useful levels of cocaine detection.

Molecular near-field antenna effect in resonance hyper-Raman scattering: Intermolecular vibronic intensity borrowing of solvent from solute through dipole-dipole and dipole-quadrupole interactions

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

Shimada, Rintaro; Hamaguchi, Hiro-o, E-mail: hhama@nctu.edu.tw

2014-05-28

We quantitatively interpret the recently discovered intriguing phenomenon related to resonance Hyper-Raman (HR) scattering. In resonance HR spectra of all-trans-β-carotene (β-carotene) in solution, vibrations of proximate solvent molecules are observed concomitantly with the solute β-carotene HR bands. It has been shown that these solvent bands are subject to marked intensity enhancements by more than 5 orders of magnitude under the presence of β-carotene. We have called this phenomenon the molecular-near field effect. Resonance HR spectra of β-carotene in benzene, deuterated benzene, cyclohexane, and deuterated cyclohexane have been measured precisely for a quantitative analysis of this effect. The assignments of themore » observed peaks are made by referring to the infrared, Raman, and HR spectra of neat solvents. It has been revealed that infrared active and some Raman active vibrations are active in the HR molecular near-field effect. The observed spectra in the form of difference spectra (between benzene/deuterated benzene and cyclohexane/deuterated cyclohexane) are quantitatively analyzed on the basis of the extended vibronic theory of resonance HR scattering. The theory incorporates the coupling of excited electronic states of β-carotene with the vibrations of a proximate solvent molecule through solute–solvent dipole–dipole and dipole–quadrupole interactions. It is shown that the infrared active modes arise from the dipole–dipole interaction, whereas Raman active modes from the dipole–quadrupole interaction. It is also shown that vibrations that give strongly polarized Raman bands are weak in the HR molecular near-field effect. The observed solvent HR spectra are simulated with the help of quantum chemical calculations for various orientations and distances of a solvent molecule with respect to the solute. The observed spectra are best simulated with random orientations of the solvent molecule at an intermolecular distance of 10 Å.« less

Optimal Control-Enabled Imaging and Spectroscopy using a Nanowire Magnetic Resonance Force Microscope

NASA Astrophysics Data System (ADS)

Rose, William; Haas, Holger; Chen, Angela; Cory, David; Budakian, Raffi

Magnetic resonance imaging (MRI) is a powerful non-invasive technique that has transformed our ability to study the structure and function of biological systems. Key to its success has been the unique ability to combine imaging with magnetic resonance spectroscopy. Although it remains a significant challenge, there is considerable interest in extending MRI spectroscopy to the nanometer scale because it would provide a fundamentally new route for determining the structure and function of complex biomolecules. We present data taken with a nanowire magnetic resonance force microscopy (MRFM) setup. We show how the capabilities of this very sensitive spin-detection system can be extended to include spectroscopy and nanometer-scale imaging by combining optimal control theory (OCT) techniques with magic echo sequences. We apply OCT-based dynamical-decoupling pulses to nanoscale ensembles of proton spins in polystyrene, and demonstrate a 500-fold line-narrowing of the proton spin resonance, from 30 kHz to 60 Hz. We further demonstrate 1-D imaging over a 35-nm region with an average voxel size of 2.2 nm. Funding provided by the U.S. Army Research Office, Grant No. W911NF-12-1-0341.

The nuclear electric quadrupole moment of antimony from the molecular method.

PubMed

Haiduke, Roberto L A; da Silva, Albérico B F; Visscher, Lucas

2006-08-14

Relativistic Dirac-Coulomb (DC) Hartree-Fock calculations are employed to obtain the analytic electric field gradient (EFG) on the antimony nucleus in the SbN, SbP, SbF, and SbCl molecules. The electronic correlation contribution to the EFGs is included with the DC-CCSD(T) and DC-CCSD-T approaches, also in the four-component framework, using a finite-difference method. The total EFG results, along with the experimental nuclear quadrupole coupling constants from microwave spectroscopy, allow to derive the nuclear quadrupole moments of (121)Sb and (123)Sb, respectively, as -543(11) and -692(14) mb.

Resonance Raman spectroscopy in malaria research.

PubMed

Wood, Bayden R; McNaughton, Don

2006-10-01

In recent years, the field of Raman spectroscopy has witnessed a surge in technological development, with the incorporation of ultrasensitive, charge-coupled devices, improved laser sources and precision Rayleigh-filter systems. This has led to the development of sensitive confocal micro-Raman spectrometers and imaging spectrometers that are capable of obtaining high spatial-resolution spectra and images of subcellular components within single living cells. This review reports on the application of resonance micro-Raman spectroscopy to the study of malaria pigment (hemozoin), a by-product of hemoglobin catabolization by the malaria parasite, which is an important target site for antimalarial drugs. The review aims to briefly describe recent studies on the application of this technology, elucidate molecular and electronic properties of the malaria pigment and its synthetic analog beta-hematin, provide insight into the mechanism of hemozoin formation within the food vacuole of the parasite, and comment on developing strategies for using this technology in drug-screening protocols.

Brain lymphoma: usefulness of the magnetic resonance spectroscopy.

PubMed

Taillibert, Sophie; Guillevin, Rémy; Menuel, Carole; Sanson, Marc; Hoang-Xuan, Khê; Chiras, Jacques; Duffau, Hugues

2008-01-01

The diagnosis of primary central nervous system lymphoma (PCNSL) should always be considered as an emergency because of the therapeutic consequences it implies. In immunocompetent patients, it relies on stereotactic biopsy. Unfortunately, clinical and radiological features may be misleading and delay the diagnostic procedure. The case we report here illustrates the contribution of magnetic resonance spectroscopy in the diagnostic approach of a very atypical PCNSL.

Shifts due to quantum-mechanical interference from distant neighboring resonances for saturated fluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Marsman, Alain; Horbatsch, Marko; Hessels, Eric A.

2014-05-01

Quantum-mechanical interference with distant neighboring resonances is found to cause shifts for precision saturated fluorescence spectroscopy of the atomic helium 23 S -to- 23 P transitions. The shifts are significant (larger than the experimental uncertainties for measurements of the intervals) despite the fact that the neighboring resonances are separated from the measured resonances by 1400 and 20 000 natural widths. The shifts depend strongly on experimental parameters such as the angular position of the fluorescence detector and the intensity and size of laser beams. These shifts must be considered for the ongoing program of determining the fine-structure constant from the helium 23 P fine structure. The work represents the first study of such interference shifts for saturated fluorescence spectroscopy and follows up on our previous study of similar shifts for laser spectroscopy. This work is supported by NSERC, CRC, ORF, CFI, NIST and SHARCNET.

Eight piece quadrupole magnet, method for aligning quadrupole magent pole tips

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

Jaski, Mark S.; Liu, Jie; Donnelly, Aric T.

The invention provides an alternative to the standard 2-piece or 4-piece quadrupole. For example, an 8-piece and a 10-piece quadrupole are provided whereby the tips of each pole may be adjustable. Also provided is a method for producing a quadrupole using standard machining techniques but which results in a final tolerance accuracy of the resulting construct which is better than that obtained using standard machining techniques.

Introduction to Spin Label Electron Paramagnetic Resonance Spectroscopy of Proteins

ERIC Educational Resources Information Center

Melanson, Michelle; Sood, Abha; Torok, Fanni; Torok, Marianna

2013-01-01

An undergraduate laboratory exercise is described to demonstrate the biochemical applications of electron paramagnetic resonance (EPR) spectroscopy. The beta93 cysteine residue of hemoglobin is labeled by the covalent binding of 3-maleimido-proxyl (5-MSL) and 2,2,5,5-tetramethyl-1-oxyl-3-methyl methanethiosulfonate (MTSL), respectively. The excess…

Using Nuclear Magnetic Resonance Spectroscopy for Measuring Ternary Phase Diagrams

ERIC Educational Resources Information Center

Woodworth, Jennifer K.; Terrance, Jacob C.; Hoffmann, Markus M.

2006-01-01

A laboratory experiment is presented for the upper-level undergraduate physical chemistry curriculum in which the ternary phase diagram of water, 1-propanol and n-heptane is measured using proton nuclear magnetic resonance (NMR) spectroscopy. The experiment builds upon basic concepts of NMR spectral analysis, typically taught in the undergraduate…

Resonant acoustic spectroscopy of soft tissues using embedded magnetomotive nanotransducers and optical coherence tomography

PubMed Central

Oldenburg, Amy L

2010-01-01

We present a new method for performing dynamic elastography of soft tissue samples. By sensing nanoscale displacements with optical coherence tomography, a chirped, modulated force is applied to acquire the mechanical spectrum of a tissue sample within a few seconds. This modulated force is applied via magnetic nanoparticles, named ‘nanotransducers’, which are diffused into the tissue, and which contribute negligible inertia to the soft tissue mechanical system. Using this novel system, we observed that excised tissues exhibit mechanical resonance modes which are well described by a linear damped harmonic oscillator. Results are validated by using cylindrical tissue phantoms of agarose in which resonant frequencies (30–400 Hz) are consistent with longitudinal modes and the sample boundary conditions. We furthermore show that the Young’s modulus can be computed from their measured resonance frequencies, analogous to resonant ultrasound spectroscopy for stiff material analysis. Using this new technique, named magnetomotive resonant acoustic spectroscopy (MRAS), we monitored the relative stiffening of an excised rat liver during a chemical fixation process. PMID:20124653

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

PubMed Central

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

2014-01-01

Previous studies have found that methylmercury can damage hippocampal neurons and accordingly cause cognitive dysfunction. However, a non-invasive, safe and accurate detection method for detecting hippocampal injury has yet to be developed. This study aimed to detect methylmercury-induced damage on hippocampal tissue using proton magnetic resonance spectroscopy. Rats were given a subcutaneous injection of 4 and 2 mg/kg methylmercury into the neck for 50 consecutive days. Water maze and pathology tests confirmed that cognitive function had been impaired and that the ultrastructure of hippocampal tissue was altered after injection. The results of proton magnetic resonance spectroscopy revealed that the nitrogen-acetyl aspartate/creatine, choline complex/creatine and myoinositol/creatine ratio in rat hippocampal tissue were unchanged. Therefore, proton magnetic resonance spectroscopy can not be used to determine structural damage in the adult rat hippocampus caused by methylmercury chloride. PMID:25368649

Nuclear magnetic resonance detection and spectroscopy of single proteins using quantum logic

NASA Astrophysics Data System (ADS)

Lovchinsky, I.; Sushkov, A. O.; Urbach, E.; de Leon, N. P.; Choi, S.; De Greve, K.; Evans, R.; Gertner, R.; Bersin, E.; Müller, C.; McGuinness, L.; Jelezko, F.; Walsworth, R. L.; Park, H.; Lukin, M. D.

2016-02-01

Nuclear magnetic resonance spectroscopy is a powerful tool for the structural analysis of organic compounds and biomolecules but typically requires macroscopic sample quantities. We use a sensor, which consists of two quantum bits corresponding to an electronic spin and an ancillary nuclear spin, to demonstrate room temperature magnetic resonance detection and spectroscopy of multiple nuclear species within individual ubiquitin proteins attached to the diamond surface. Using quantum logic to improve readout fidelity and a surface-treatment technique to extend the spin coherence time of shallow nitrogen-vacancy centers, we demonstrate magnetic field sensitivity sufficient to detect individual proton spins within 1 second of integration. This gain in sensitivity enables high-confidence detection of individual proteins and allows us to observe spectral features that reveal information about their chemical composition.

Clocking Femtosecond Collisional Dynamics via Resonant X-Ray Spectroscopy

NASA Astrophysics Data System (ADS)

van den Berg, Q. Y.; Fernandez-Tello, E. V.; Burian, T.; Chalupský, J.; Chung, H.-K.; Ciricosta, O.; Dakovski, G. L.; Hájková, V.; Hollebon, P.; Juha, L.; Krzywinski, J.; Lee, R. W.; Minitti, M. P.; Preston, T. R.; de la Varga, A. G.; Vozda, V.; Zastrau, U.; Wark, J. S.; Velarde, P.; Vinko, S. M.

2018-02-01

Electron-ion collisional dynamics is of fundamental importance in determining plasma transport properties, nonequilibrium plasma evolution, and electron damage in diffraction imaging applications using bright x-ray free-electron lasers (FELs). Here we describe the first experimental measurements of ultrafast electron impact collisional ionization dynamics using resonant core-hole spectroscopy in a solid-density magnesium plasma, created and diagnosed with the Linac Coherent Light Source x-ray FEL. By resonantly pumping the 1 s →2 p transition in highly charged ions within an optically thin plasma, we have measured how off-resonance charge states are populated via collisional processes on femtosecond time scales. We present a collisional cross section model that matches our results and demonstrates how the cross sections are enhanced by dense-plasma effects including continuum lowering. Nonlocal thermodynamic equilibrium collisional radiative simulations show excellent agreement with the experimental results and provide new insight on collisional ionization and three-body-recombination processes in the dense-plasma regime.

Non-Destructive Evaluation of Kissing Bonds using Local Defect Resonance (LDR) Spectroscopy: A Simulation Study

NASA Astrophysics Data System (ADS)

Delrue, S.; Tabatabaeipour, M.; Hettler, J.; Van Den Abeele, K.

With the growing demand from industry to optimize and further develop existing Non-Destructive Testing & Evaluation (NDT&E) techniques or new methods to detect and characterize incipient damage with high sensitivity and increased quality, ample efforts have been devoted to better understand the typical behavior of kissing bonds, such as delaminations and cracks. Recently, it has been shown experimentally that the nonlinear ultrasonic response of kissing bonds could be enhanced by using Local Defect Resonance (LDR) spectroscopy. LDR spectroscopy is an efficient NDT technique that takes advantage of the characteristic fre- quencies of the defect (defect resonances) in order to provide maximum acoustic wave-defect interaction. In fact, for nonlinear methodologies, the ultrasonic excitation of the sample should occur at either multiples or integer ratios of the characteristic defect resonance frequencies, in order to obtain the highest signal-to-noise response in the nonlinear LDR spectroscopy. In this paper, the potential of using LDR spectroscopy for the detection, localization and characterization of kissing bonds is illustrated using a 3D simulation code for elastic wave propagation in materials containing closed but dynamically active cracks or delaminations. Using the model, we are able to define an appropriate method, based on the Scaling Subtraction Method (SSM), to determine the local defect resonance frequencies of a delamination in a composite plate and to illustrate an increase in defect nonlinearity due to LDR. The simulation results will help us to obtain a better understanding of the concept of LDR and to assist in the further design and testing of LDR spectroscopy for the detection, localization and characterization of kissing bonds.

Kinetic modeling of active plasma resonance spectroscopy

NASA Astrophysics Data System (ADS)

Oberrath, Jens

2016-09-01

The term ``active plasma resonance spectroscopy'' (APRS) refers to a plasma diagnostic method which employs the natural ability of plasmas to resonate close to the plasma frequency. Essential for this method is an appropriate model to determine the relation between the resonance parameters and demanded plasma parameters. Measurements with these probes in plasmas of a few Pa typically show a broadening of the spectrum that cannot be predicted by a fluid model. Thus, a kinetic model is necessary. A general kinetic model of APRS probes, which can be described in electorstatic approximation, valid for all pressures has been presented. This model is used to analyze the dynamic behavior of such probes by means of functional analytic methods. One of the main results is, that the system response function Y (ω) is given in terms of the matrix elements of the resolvent of the dynamic operator evaluated for values on the imaginary axis. The spectrum of this operator is continuous which implies a new phenomenon related to anomalous or non-collisional dissipation. Based on the scalar product, which is motivated by the kinetic free energy, the non-collisional damping can be interpreted: In a periodic state, the probe constantly emits plasma waves which propagate to ``infinity''. The free energy simply leaves the ``observation range'' of the probe which is recorded as damping. The kinetic damping, which depends on the mean kinetic energy of the electrons, is responsible for the broadening of a resonance peak in the measured spectrum of APRS probes. The ultimate goal is to determine explicit formulas for the relation between the broadening of the resonance peak and the ``equivalent electron temperature'', especially in the case of the spherical Impedance Probe and the Multipole Resonance Probe. Gratitude is expressed to the internal funding of Leuphana University, the BMBF via PluTO+, the DFG via Collaborative Research Center TR 87, and the Ruhr University Research School.

Molecular aspects of magnetic resonance imaging and spectroscopy.

PubMed

Boesch, C

1999-01-01

Magnetic resonance imaging (MRI) is a well known diagnostic tool in radiology that produces unsurpassed images of the human body, in particular of soft tissue. However, the medical community is often not aware that MRI is an important yet limited segment of magnetic resonance (MR) or nuclear magnetic resonance (NMR) as this method is called in basic science. The tremendous morphological information of MR images sometimes conceal the fact that MR signals in general contain much more information, especially on processes on the molecular level. NMR is successfully used in physics, chemistry, and biology to explore and characterize chemical reactions, molecular conformations, biochemical pathways, solid state material, and many other applications that elucidate invisible characteristics of matter and tissue. In medical applications, knowledge of the molecular background of MRI and in particular MR spectroscopy (MRS) is an inevitable basis to understand molecular phenomenon leading to macroscopic effects visible in diagnostic images or spectra. This review shall provide the necessary background to comprehend molecular aspects of magnetic resonance applications in medicine. An introduction into the physical basics aims at an understanding of some of the molecular mechanisms without extended mathematical treatment. The MR typical terminology is explained such that reading of original MR publications could be facilitated for non-MR experts. Applications in MRI and MRS are intended to illustrate the consequences of molecular effects on images and spectra.

Structures and Nuclear Quadrupole Coupling Tensors of a Series of Chlorine-Containing Hydrocarbons

NASA Astrophysics Data System (ADS)

Dikkumbura, Asela S.; Webster, Erica R.; Dorris, Rachel E.; Peebles, Rebecca A.; Peebles, Sean A.; Seifert, Nathan A.; Pate, Brooks

2016-06-01

Rotational spectra for gauche-1,2-dichloroethane (12DCE), gauche-1-chloro-2-fluoroethane (1C2FE) and both anti- and gauche-2,3-dichloropropene (23DCP) have been observed using chirped-pulse Fourier-transform microwave (FTMW) spectroscopy in the 6-18 GHz region. Although the anti conformers for all three species are predicted to be more stable than the gauche forms, they are nonpolar (12DCE) or nearly nonpolar (predicted dipole components for anti-1C2FE: μ_a = 0.11 D, μ_b = 0.02 D and for anti-23DCP: μ_a = 0.25 D, μ_b = 0.02 D); nevertheless, it was also possible to observe and assign the spectrum of anti-23DCP. Assignments of parent spectra and 37Cl and 13C substituted isotopologues utilized predictions at the MP2/6-311++G(2d,2p) level and Pickett's SPCAT/SPFIT programs. For the weak anti-23DCP spectra, additional measurements also utilized a resonant-cavity FTMW spectrometer. Full chlorine nuclear quadrupole coupling tensors for gauche-12DCE and both anti- and gauche-23DCP have been diagonalized to allow comparison of coupling constants. Kraitchman's equations were used to determine r_s coordinates of isotopically substituted atoms and r_0 structures were also deduced for gauche conformers of 12DCE and 1C2FE. Structural details and chlorine nuclear quadrupole coupling constants of all three molecules will be compared, and effects of differing halogen substitution and carbon chain length on molecular properties will be evaluated.

Magnetic resonance imaging and spectroscopy of the murine cardiovascular system.

PubMed

Akki, Ashwin; Gupta, Ashish; Weiss, Robert G

2013-03-01

Magnetic resonance imaging (MRI) has emerged as a powerful and reliable tool to noninvasively study the cardiovascular system in clinical practice. Because transgenic mouse models have assumed a critical role in cardiovascular research, technological advances in MRI have been extended to mice over the last decade. These have provided critical insights into cardiac and vascular morphology, function, and physiology/pathophysiology in many murine models of heart disease. Furthermore, magnetic resonance spectroscopy (MRS) has allowed the nondestructive study of myocardial metabolism in both isolated hearts and in intact mice. This article reviews the current techniques and important pathophysiological insights from the application of MRI/MRS technology to murine models of cardiovascular disease.

High-Yield Spin Labeling of Long RNAs for Electron Paramagnetic Resonance Spectroscopy.

PubMed

Kerzhner, Mark; Matsuoka, Hideto; Wuebben, Christine; Famulok, Michael; Schiemann, Olav

2018-05-10

Site-directed spin labeling is a powerful tool for investigating the conformation and dynamics of biomacromolecules such as RNA. Here we introduce a spin labeling strategy based on click chemistry in solution that, in combination with enzymatic ligation, allows highly efficient labeling of complex and long RNAs with short reaction times and suppressed RNA degradation. With this approach, a 34-nucleotide aptamer domain of the preQ1 riboswitch and an 81-nucleotide TPP riboswitch aptamer could be labeled with two labels in several positions. We then show that conformations of the preQ1 aptamer and its dynamics can be monitored in the absence and presence of Mg 2+ and a preQ1 ligand by continuous wave electron paramagnetic resonance spectroscopy at room temperature and pulsed electron-electron double resonance spectroscopy (PELDOR or DEER) in the frozen state.

Nuclear magnetic resonance detection and spectroscopy of single proteins using quantum logic.

PubMed

Lovchinsky, I; Sushkov, A O; Urbach, E; de Leon, N P; Choi, S; De Greve, K; Evans, R; Gertner, R; Bersin, E; Müller, C; McGuinness, L; Jelezko, F; Walsworth, R L; Park, H; Lukin, M D

2016-02-19

Nuclear magnetic resonance spectroscopy is a powerful tool for the structural analysis of organic compounds and biomolecules but typically requires macroscopic sample quantities. We use a sensor, which consists of two quantum bits corresponding to an electronic spin and an ancillary nuclear spin, to demonstrate room temperature magnetic resonance detection and spectroscopy of multiple nuclear species within individual ubiquitin proteins attached to the diamond surface. Using quantum logic to improve readout fidelity and a surface-treatment technique to extend the spin coherence time of shallow nitrogen-vacancy centers, we demonstrate magnetic field sensitivity sufficient to detect individual proton spins within 1 second of integration. This gain in sensitivity enables high-confidence detection of individual proteins and allows us to observe spectral features that reveal information about their chemical composition. Copyright © 2016, American Association for the Advancement of Science.

Electronic resonances in broadband stimulated Raman spectroscopy

NASA Astrophysics Data System (ADS)

Batignani, G.; Pontecorvo, E.; Giovannetti, G.; Ferrante, C.; Fumero, G.; Scopigno, T.

2016-01-01

Spontaneous Raman spectroscopy is a formidable tool to probe molecular vibrations. Under electronic resonance conditions, the cross section can be selectively enhanced enabling structural sensitivity to specific chromophores and reaction centers. The addition of an ultrashort, broadband femtosecond pulse to the excitation field allows for coherent stimulation of diverse molecular vibrations. Within such a scheme, vibrational spectra are engraved onto a highly directional field, and can be heterodyne detected overwhelming fluorescence and other incoherent signals. At variance with spontaneous resonance Raman, however, interpreting the spectral information is not straightforward, due to the manifold of field interactions concurring to the third order nonlinear response. Taking as an example vibrational spectra of heme proteins excited in the Soret band, we introduce a general approach to extract the stimulated Raman excitation profiles from complex spectral lineshapes. Specifically, by a quantum treatment of the matter through density matrix description of the third order nonlinear polarization, we identify the contributions which generate the Raman bands, by taking into account for the cross section of each process.

Low-energy d-d excitations in MnO studied by resonant x-ray fluorescence spectroscopy

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

Butorin, S.M.; Guo, J.; Magnuson, M.

1997-04-01

Resonant soft X-ray emission spectroscopy has been demonstrated to possess interesting abilities for studies of electronic structure in various systems, such as symmetry probing, alignment and polarization dependence, sensitivity to channel interference, etc. In the present abstract the authors focus on the feasibility of resonant soft X-ray emission to probe low energy excitations by means of resonant electronic X-ray Raman scattering. Resonant X-ray emission can be regarded as an inelastic scattering process where a system in the ground state is transferred to a low excited state via a virtual core excitation. The energy closeness to a core excitation of themore » exciting radiation enhances the (generally) low probability for inelastic scattering at these wavelengths. Therefore soft X-ray emission spectroscopy (in resonant electronic Raman mode) can be used to study low energy d-d excitations in transition metal systems. The involvement of the intermediate core state allows one to use the selection rules of X-ray emission, and the appearance of the elastically scattered line in the spectra provides the reference to the ground state.« less

NQRS Data for C24H20BRb (Subst. No. 1578)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for C24H20BRb (Subst. No. 1578)

NQRS Data for H4INO3 (Subst. No. 2276)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for H4INO3 (Subst. No. 2276)

NQRS Data for D4INO4 (Subst. No. 2163)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for D4INO4 (Subst. No. 2163)

NQRS Data for H4INO4 (Subst. No. 2277)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for H4INO4 (Subst. No. 2277)

Nqrs Data for C2H5NO2 (Subst. No. 0554)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C2H5NO2 (Subst. No. 0554)

NQRS Data for Ga3LaPd2 (Subst. No. 2229)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for Ga3LaPd2 (Subst. No. 2229)

NQRS Data for CoLa4LiO8(Subst. No. 1970)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for CoLa4LiO8 (Subst. No. 1970)

NQRS Data for AlDO28Si13 (Subst. No. 0033)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for AlDO28Si13 (Subst. No. 0033)

NQRS Data for AlDO70Si34 (Subst. No. 0035)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for AlDO70Si34 (Subst. No. 0035)

NQRS Data for AlDO28Si13 (Subst. No. 0034)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for AlDO28Si13 (Subst. No. 0034)

NQRS Data for AlDO2 [Al(OD)O] (Subst. No. 0032)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for AlDO2 [Al(OD)O] (Subst. No. 0032)

Accelerating two-dimensional nuclear magnetic resonance correlation spectroscopy via selective coherence transfer

NASA Astrophysics Data System (ADS)

Ye, Qimiao; Chen, Lin; Qiu, Wenqi; Lin, Liangjie; Sun, Huijun; Cai, Shuhui; Wei, Zhiliang; Chen, Zhong

2017-01-01

Nuclear magnetic resonance (NMR) spectroscopy serves as an important tool for both qualitative and quantitative analyses of various systems in chemistry, biology, and medicine. However, applications of one-dimensional 1H NMR are often restrained by the presence of severe overlap among different resonances. The advent of two-dimensional (2D) 1H NMR constitutes a promising alternative by extending the crowded resonances into a plane and thereby alleviating the spectral congestions. However, the enhanced ability in discriminating resonances is achieved at the cost of extended experimental duration due to necessity of various scans with progressive delays to construct the indirect dimension. Therefore, in this study, we propose a selective coherence transfer (SECOT) method to accelerate acquisitions of 2D correlation spectroscopy by converting chemical shifts into spatial positions within the effective sample length and then performing an echo planar spectroscopic imaging module to record the spatial and spectral information, which generates 2D correlation spectrum after 2D Fourier transformation. The feasibility and effectiveness of SECOT have been verified by a set of experiments under both homogeneous and inhomogeneous magnetic fields. Moreover, evaluations of SECOT for quantitative analyses are carried out on samples with a series of different concentrations. Based on these experimental results, the SECOT may open important perspectives for fast, accurate, and stable investigations of various chemical systems both qualitatively and quantitatively.

Wavelet signatures of K-splitting of the Isoscalar Giant Quadrupole Resonance in deformed nuclei from high-resolution (p,p‧) scattering off 146, 148, 150Nd

NASA Astrophysics Data System (ADS)

Kureba, C. O.; Buthelezi, Z.; Carter, J.; Cooper, G. R. J.; Fearick, R. W.; Förtsch, S. V.; Jingo, M.; Kleinig, W.; Krugmann, A.; Krumbolz, A. M.; Kvasil, J.; Mabiala, J.; Mira, J. P.; Nesterenko, V. O.; von Neumann-Cosel, P.; Neveling, R.; Papka, P.; Reinhard, P.-G.; Richter, A.; Sideras-Haddad, E.; Smit, F. D.; Steyn, G. F.; Swartz, J. A.; Tamii, A.; Usman, I. T.

2018-04-01

The phenomenon of fine structure of the Isoscalar Giant Quadrupole Resonance (ISGQR) has been studied with high energy-resolution proton inelastic scattering at iThemba LABS in the chain of stable even-mass Nd isotopes covering the transition from spherical to deformed ground states. A wavelet analysis of the background-subtracted spectra in the deformed 146, 148, 150Nd isotopes reveals characteristic scales in correspondence with scales obtained from a Skyrme RPA calculation using the SVmas10 parameterization. A semblance analysis shows that these scales arise from the energy shift between the main fragments of the K = 0 , 1 and K = 2 components.

Probing local bias-induced transitions using photothermal excitation contact resonance atomic force microscopy and voltage spectroscopy

DOE PAGES

Li, Qian; Jesse, Stephen; Tselev, Alexander; ...

2015-01-05

In this paper, nanomechanical properties are closely related to the states of matter, including chemical composition, crystal structure, mesoscopic domain configuration, etc. Investigation of these properties at the nanoscale requires not only static imaging methods, e.g., contact resonance atomic force microscopy (CR-AFM), but also spectroscopic methods capable of revealing their dependence on various external stimuli. Here we demonstrate the voltage spectroscopy of CR-AFM, which was realized by combining photothermal excitation (as opposed to the conventional piezoacoustic excitation method) with the band excitation technique. We applied this spectroscopy to explore local bias-induced phenomena ranging from purely physical to surface electromechanical andmore » electrochemical processes. Our measurements show that the changes in the surface properties associated with these bias-induced transitions can be accurately assessed in a fast and dynamic manner, using resonance frequency as a signature. Finally, with many of the advantages offered by photothermal excitation, contact resonance voltage spectroscopy not only is expected to find applications in a broader field of nanoscience but also will provide a basis for future development of other nanoscale elastic spectroscopies.« less

Magnetic Resonance Spectroscopy: An Objective Technique for the Quantification of Prostate Cancer Pathologies

DTIC Science & Technology

2007-02-01

5d. PROJECT NUMBER Leo L. Cheng, Ph.D. 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S...Scott RM, Anthony DC, Gonzalez RG, Black PM. Biochemical characterization of pediatric brain tumors by using in vivo and ex vivo magnetic resonance...Biochemical characterization of pediatric brain tumors by using in vivo and ex vivo magnetic resonance spectroscopy. J Neurosurg 2002;96: 1023–1031. 7

Childhood temporal lobe epilepsy: correlation between electroencephalography and magnetic resonance spectroscopy: a case-control study.

PubMed

Azab, Seham Fa; Sherief, Laila M; Saleh, Safaa H; Elshafeiy, Mona M; Siam, Ahmed G; Elsaeed, Wafaa F; Arafa, Mohamed A; Bendary, Eman A; Sherbiny, Hanan S; Elbehedy, Rabab M; Aziz, Khalid A

2015-04-18

The diagnosis of epilepsy should be made as early as possible to give a child the best chance for treatment success and also to decrease complications such as learning difficulties and social and behavioral problems. In this study, we aimed to assess the ability of magnetic resonance spectroscopy (MRS) in detecting the lateralization side in patients with Temporal lobe epilepsy (TLE) in correlation with EEG and MRI findings. This was a case-control study including 40 patients diagnosed (clinically and by EEG) as having temporal lobe epilepsy aged 8 to 14 years (mean, 10.4 years) and 20 healthy children with comparable age and gender as the control group. All patients were subjected to clinical examination, interictal electroencephalography and magnetic resonance imaging (MRI). Proton magnetic resonance spectroscopic examination (MRS) was performed to the patients and the controls. According to the findings of electroencephalography, our patients were classified to three groups: Group 1 included 20 patients with unitemporal (lateralized) epileptic focus, group 2 included 12 patients with bitemporal (non-lateralized) epileptic focus and group 3 included 8 patients with normal electroencephalography. Magnetic resonance spectroscopy could lateralize the epileptic focus in 19 patients in group 1, nine patients in group2 and five patients in group 3 with overall lateralization of (82.5%), while electroencephalography was able to lateralize the focus in (50%) of patients and magnetic resonance imaging detected lateralization of mesial temporal sclerosis in (57.5%) of patients. Magnetic resonance spectroscopy is a promising tool in evaluating patients with epilepsy and offers increased sensitivity to detect temporal pathology that is not obvious on structural MRI imaging.

Measuring molecular parity nonconservation using nuclear-magnetic-resonance spectroscopy

DOE PAGES

Eills, J.; Blanchard, J. W.; Bougas, L.; ...

2017-10-30

Here, the weak interaction does not conserve parity and therefore induces energy shifts in chiral enantiomers that should in principle be detectable in molecular spectra. Unfortunately, the magnitude of the expected shifts are small and in spectra of a mixture of enantiomers, the energy shifts are not resolvable. We propose a nuclear-magnetic-resonance (NMR) experiment in which we titrate the chirality (enantiomeric excess) of a solvent and measure the diasteriomeric splitting in the spectra of a chiral solute in order to search for an anomalous offset due to parity nonconservation (PNC). We present a proof-of-principle experiment in which we search formore » PNC in the 13C resonances of small molecules, and use the 1H resonances, which are insensitive to PNC, as an internal reference. We set a constraint on molecular PNC in 13C chemical shifts at a level of 10 –5 ppm, and provide a discussion of important considerations in the search for molecular PNC using NMR spectroscopy.« less

Measuring molecular parity nonconservation using nuclear-magnetic-resonance spectroscopy

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

Eills, J.; Blanchard, J. W.; Bougas, L.

Here, the weak interaction does not conserve parity and therefore induces energy shifts in chiral enantiomers that should in principle be detectable in molecular spectra. Unfortunately, the magnitude of the expected shifts are small and in spectra of a mixture of enantiomers, the energy shifts are not resolvable. We propose a nuclear-magnetic-resonance (NMR) experiment in which we titrate the chirality (enantiomeric excess) of a solvent and measure the diasteriomeric splitting in the spectra of a chiral solute in order to search for an anomalous offset due to parity nonconservation (PNC). We present a proof-of-principle experiment in which we search formore » PNC in the 13C resonances of small molecules, and use the 1H resonances, which are insensitive to PNC, as an internal reference. We set a constraint on molecular PNC in 13C chemical shifts at a level of 10 –5 ppm, and provide a discussion of important considerations in the search for molecular PNC using NMR spectroscopy.« less

Clocking Femtosecond Collisional Dynamics via Resonant X-Ray Spectroscopy

DOE PAGES

van den Berg, Q. Y.; Fernandez-Tello, E. V.; Burian, T.; ...

2018-02-01

Electron-ion collisional dynamics is of fundamental importance in determining plasma transport properties, nonequilibrium plasma evolution, and electron damage in diffraction imaging applications using bright x-ray free-electron lasers (FELs). Here in this paper, we describe the first experimental measurements of ultrafast electron impact collisional ionization dynamics using resonant core-hole spectroscopy in a solid-density magnesium plasma, created and diagnosed with the Linac Coherent Light Source x-ray FEL. By resonantly pumping the 1s → 2p transition in highly charged ions within an optically thin plasma, we have measured how off-resonance charge states are populated via collisional processes on femtosecond time scales. We presentmore » a collisional cross section model that matches our results and demonstrates how the cross sections are enhanced by dense-plasma effects including continuum lowering. Nonlocal thermodynamic equilibrium collisional radiative simulations show excellent agreement with the experimental results and provide new insight on collisional ionization and three-body-recombination processes in the dense-plasma regime.« less

Magnetic resonance imaging and spectroscopy of the murine cardiovascular system

PubMed Central

Akki, Ashwin; Gupta, Ashish

2013-01-01

Magnetic resonance imaging (MRI) has emerged as a powerful and reliable tool to noninvasively study the cardiovascular system in clinical practice. Because transgenic mouse models have assumed a critical role in cardiovascular research, technological advances in MRI have been extended to mice over the last decade. These have provided critical insights into cardiac and vascular morphology, function, and physiology/pathophysiology in many murine models of heart disease. Furthermore, magnetic resonance spectroscopy (MRS) has allowed the nondestructive study of myocardial metabolism in both isolated hearts and in intact mice. This article reviews the current techniques and important pathophysiological insights from the application of MRI/MRS technology to murine models of cardiovascular disease. PMID:23292717

Far off-resonance laser frequency stabilization using multipass cells in Faraday rotation spectroscopy.

PubMed

Quan, Wei; Li, Yang; Li, Rujie; Shang, Huining; Fang, Zishan; Qin, Jie; Wan, Shuangai

2016-04-01

We propose a far off-resonance laser frequency stabilization method by using multipass cells in Rb Faraday rotation spectroscopy. Based on the detuning equation, if multipass cells with several meters optical path length are used in the conventional Faraday spectroscopy, the detuning of the lock point can be extended much further from the alkali metal resonance. A plate beam splitter was used to generate two different Faraday signals at the same time. The transmitted optical path length was L=50  mm and the reflected optical path length was 2L=100  mm. When the optical path length doubled, the detuning of the lock points moved further away from the atomic resonance. The temperature dependence of the detuning of the lock point was also analyzed. A temperature-insensitive lock point was found near resonance when the cell temperature was between 110°C and 130°C. We achieved an rms fluctuation of 0.9 MHz/23 h at a detuning of 0.5 GHz. A frequency drift of 16 MHz/h at a detuning of -5.6  GHz and 4 MHz/h at a detuning of -5.2  GHz were also obtained for the transmitted and reflected light Faraday signal.

Magnetic resonance spectroscopy of normal appearing white matter in early relapsing-remitting multiple sclerosis: correlations between disability and spectroscopy

PubMed Central

Ruiz-Peña, Juan Luis; Piñero, Pilar; Sellers, Guillermo; Argente, Joaquín; Casado, Alfredo; Foronda, Jesus; Uclés, Antonio; Izquierdo, Guillermo

2004-01-01

Background What currently appears to be irreversible axonal loss in normal appearing white matter, measured by proton magnetic resonance spectroscopy is of great interest in the study of Multiple Sclerosis. Our aim is to determine the axonal damage in normal appearing white matter measured by magnetic resonance spectroscopy and to correlate this with the functional disability measured by Multiple Sclerosis Functional Composite scale, Neurological Rating Scale, Ambulation Index scale, and Expanded Disability Scale Score. Methods Thirty one patients (9 male and 22 female) with relapsing remitting Multiple Sclerosis and a Kurtzke Expanded Disability Scale Score of 0–5.5 were recruited from four hospitals in Andalusia, Spain and included in the study. Magnetic resonance spectroscopy scans and neurological disability assessments were performed the same day. Results A statistically significant correlation was found (r = -0.38 p < 0.05) between disability (measured by Expanded Disability Scale Score) and N-Acetyl Aspartate (NAA/Cr ratio) levels in normal appearing white matter in these patients. No correlation was found between the NAA/Cr ratio and disability measured by any of the other disability assessment scales. Conclusions There is correlation between disability (measured by Expanded Disability Scale Score) and the NAA/Cr ratio in normal appearing white matter. The lack of correlation between the NAA/Cr ratio and the Multiple Sclerosis Functional Composite score indicates that the Multiple Sclerosis Functional Composite is not able to measure irreversible disability and would be more useful as a marker in stages where axonal damage is not a predominant factor. PMID:15191618

Oral glutamine challenge and magnetic resonance spectroscopy in three patients with congenital portosystemic shunts.

PubMed

Ortiz, María; Córdoba, Juan; Alonso, Juli; Rovira, Alex; Quiroga, Sergi; Jacas, Carlos; Esteban, Rafael; Guardia, Jaume

2004-03-01

Congenital portosystemic shunts are rare abnormalities of liver vasculature that can cause neurological symptoms, probably secondarily to the effects of the metabolism of ammonia in the brain. Our aim was to investigate the relationship between capillary blood ammonia after oral glutamine challenge and magnetic resonance spectroscopy in three patients with congenital portosystemic shunts. Neuropsychological tests, oral glutamine challenge and magnetic resonance spectroscopy were performed at baseline and after 6 months of follow-up in three patients with congenital portosystemic shunts. The results were compared to those obtained in a group of six cirrhotic patients with prior episodes of hepatic encephalopathy and healthy controls. Patients with congenital portosystemic shunts exhibited abnormalities of neuropsychological tests, magnetic resonance spectroscopy and a response to the oral glutamine challenge similar to those observed in patients with cirrhosis. The intensity of the rise of brain glutamine was correlated to the area under the curve of ammonia after the oral glutamine challenge (R=0.72). Neurological manifestations of patients with congenital portosystemic shunts are mediated through similar mechanisms that are involved in the pathogenesis of hepatic encephalopathy. The area under the curve appears to be the better parameter that defines the response to the oral glutamine challenge.

Monitoring Cartilage Tissue Engineering Using Magnetic Resonance Spectroscopy, Imaging, and Elastography

PubMed Central

Klatt, Dieter; Magin, Richard L.

2013-01-01

A key technical challenge in cartilage tissue engineering is the development of a noninvasive method for monitoring the composition, structure, and function of the tissue at different growth stages. Due to its noninvasive, three-dimensional imaging capabilities and the breadth of available contrast mechanisms, magnetic resonance imaging (MRI) techniques can be expected to play a leading role in assessing engineered cartilage. In this review, we describe the new MR-based tools (spectroscopy, imaging, and elastography) that can provide quantitative biomarkers for cartilage tissue development both in vitro and in vivo. Magnetic resonance spectroscopy can identify the changing molecular structure and alternations in the conformation of major macromolecules (collagen and proteoglycans) using parameters such as chemical shift, relaxation rates, and magnetic spin couplings. MRI provides high-resolution images whose contrast reflects developing tissue microstructure and porosity through changes in local relaxation times and the apparent diffusion coefficient. Magnetic resonance elastography uses low-frequency mechanical vibrations in conjunction with MRI to measure soft tissue mechanical properties (shear modulus and viscosity). When combined, these three techniques provide a noninvasive, multiscale window for characterizing cartilage tissue growth at all stages of tissue development, from the initial cell seeding of scaffolds to the development of the extracellular matrix during construct incubation, and finally, to the postimplantation assessment of tissue integration in animals and patients. PMID:23574498

OXSA: An open-source magnetic resonance spectroscopy analysis toolbox in MATLAB.

PubMed

Purvis, Lucian A B; Clarke, William T; Biasiolli, Luca; Valkovič, Ladislav; Robson, Matthew D; Rodgers, Christopher T

2017-01-01

In vivo magnetic resonance spectroscopy provides insight into metabolism in the human body. New acquisition protocols are often proposed to improve the quality or efficiency of data collection. Processing pipelines must also be developed to use these data optimally. Current fitting software is either targeted at general spectroscopy fitting, or for specific protocols. We therefore introduce the MATLAB-based OXford Spectroscopy Analysis (OXSA) toolbox to allow researchers to rapidly develop their own customised processing pipelines. The toolbox aims to simplify development by: being easy to install and use; seamlessly importing Siemens Digital Imaging and Communications in Medicine (DICOM) standard data; allowing visualisation of spectroscopy data; offering a robust fitting routine; flexibly specifying prior knowledge when fitting; and allowing batch processing of spectra. This article demonstrates how each of these criteria have been fulfilled, and gives technical details about the implementation in MATLAB. The code is freely available to download from https://github.com/oxsatoolbox/oxsa.

Nqrs Data for C6H7F4N2OSb (Subst. No. 0879)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C6H7F4N2OSb (Subst. No. 0879)

NQRS Data for C7H8Cl3Osb (Subst. No. 1005)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C7H8Cl3OSb (Subst. No. 1005)

Nqrs Data for C6H7F7N2OSb2 (Subst. No. 0880)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C6H7F7N2OSb2 (Subst. No. 0880)

Nqrs Data for C24H36Cu2N6 (Subst. No. 1586)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for C24H36Cu2N6 (Subst. No. 1586)

NQRS Data for CaCu2La2O6(Subst. No. 1756)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for CaCu2La2O6 (Subst. No. 1756)

Nqrs Data for C26H34N2O3V (Subst. No. 1601)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for C26H34N2O3V (Subst. No. 1601)

Nqrs Data for C26H35Br2CuP2 (Subst. No. 1603)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for C26H35Br2CuP2 (Subst. No. 1603)

NQRS Data for CoLa0.5O3Sr0.5(Subst. No. 1964)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for CoLa0.5O3Sr0.5 (Subst. No. 1964)

NQRS Data for CoLa0.75O3Sr0.25(Subst. No. 1967)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for CoLa0.75O3Sr0.25 (Subst. No. 1967)

NQRS Data for CoLa0.8O3Sr0.2(Subst. No. 1968)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for CoLa0.8O3Sr0.2 (Subst. No. 1968)

NQRS Data for CoLa0.7O3Sr0.3(Subst. No. 1966)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for CoLa0.7O3Sr0.3 (Subst. No. 1966)

NQRS Data for CoLa0.6O3Sr0.4(Subst. No. 1965)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for CoLa0.6O3Sr0.4 (Subst. No. 1965)

Nqrs Data for C24H42Li2N4 (Subst. No. 1587)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for C24H42Li2N4 (Subst. No. 1587)

Nqrs Data for C26H38N2O3 (Subst. No. 1607)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for C26H38N2O3 (Subst. No. 1607)

Nqrs Data for Ca9Cu24O41Sr5(Subst. No. 1776)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for Ca9Cu24O41Sr5 (Subst. No. 1776)

Nqrs Data for C24H24Cu2N6 (Subst. No. 1584)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for C24H24Cu2N6 (Subst. No. 1584)

Application of 57Fe Mössbauer spectroscopy as a tool for mining exploration of bornite (Cu5FeS4) copper ore

NASA Astrophysics Data System (ADS)

Gainov, R. R.; Vagizov, F. G.; Golovanevskiy, V. A.; Ksenofontov, V. A.; Klingelhöfer, G.; Klekovkina, V. V.; Shumilova, T. G.; Pen'kov, I. N.

2014-04-01

Nuclear resonance methods, including Mössbauer spectroscopy,are considered as unique techniques suitable for remote on-line mineralogical analysis. The employment of these methods provides potentially significant commercial benefits for mining industry. As applied to copper sulfide ores, Mössbauer spectroscopy method is suitable for the analysis noted. Bornite (formally Cu5FeS4) is a significant part of copper ore and identification of its properties is important for economic exploitation of commercial copper ore deposits. A series of natural bornite samples was studied by 57Fe Mössbauer spectroscopy. Two aspects were considered: reexamination of 57Fe Mössbauer properties of natural bornite samples and their stability irrespective of origin and potential use of miniaturized Mössbauer spectrometers MIMOS II for in-situ bornite identification. The results obtained show a number of potential benefits of introducing the available portative Mössbauer equipment into the mining industry for express mineralogical analysis. In addition, results of some preliminary 63,65Cu nuclear quadrupole resonance (NQR) studies of bornite are reported and their merits with Mössbauer techniques for bornite detection discussed.

Magnetic resonance spectroscopy and imaging for the study of fossils.

PubMed

Giovannetti, Giulio; Guerrini, Andrea; Salvadori, Piero A

2016-07-01

Computed tomography (CT) has long been used for investigating palaeontological specimens, as it is a nondestructive technique which avoids the need to dissolve or ionize the fossil sample. However, magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) have recently gained ground as analytical tools for examination of palaeontological samples, by nondestructively providing information about the structure and composition of fossils. While MRI techniques are able to reveal the three-dimensional geometry of the trace fossil, MRS can provide information on the chemical composition of the samples. The multidimensional nature of MR (magnetic resonance) signals has potential to provide rich three-dimensional data on the palaeontological specimens and also to help in elucidating paleopathological and paleoecological questions. In this work the verified applications and the emerging uses of MRI and MRS in paleontology are reviewed, with particular attention to fossil spores, fossil plants, ambers, fossil invertebrates, and fossil vertebrate studies. Copyright © 2016 Elsevier Inc. All rights reserved.

Acoustic resonance spectroscopy (ARS): ARS300 operations manual, software version 2.01

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

NONE

Acoustic Resonance Spectroscopy (ARS) is a nondestructive evaluation technology developed at the Los Alamos National Laboratory. The ARS technique is a fast, safe, and nonintrusive technique that is particularly useful when a large number of objects need to be tested. Any physical object, whether solid, hollow, or fluid filled, has many modes of vibration. These modes of vibration, commonly referred to as the natural resonant modes or resonant frequencies, are determined by the object`s shape, size, and physical properties, such as elastic moduli, speed of sound, and density. If the object is mechanically excited at frequencies corresponding to its characteristicmore » natural vibrational modes, a resonance effect can be observed when small excitation energies produce large amplitude vibrations in the object. At other excitation frequencies, i.e., vibrational response of the object is minimal.« less

Quantitative Analysis of Nail Polish Remover Using Nuclear Magnetic Resonance Spectroscopy Revisited

ERIC Educational Resources Information Center

Hoffmann, Markus M.; Caccamis, Joshua T.; Heitz, Mark P.; Schlecht, Kenneth D.

2008-01-01

Substantial modifications are presented for a previously described experiment using nuclear magnetic resonance (NMR) spectroscopy to quantitatively determine analytes in commercial nail polish remover. The revised experiment is intended for a second- or third-year laboratory course in analytical chemistry and can be conducted for larger laboratory…

Proton Magnetic Resonance Spectroscopy in Social Anxiety Disorder.

PubMed

Tükel, Raşit; Aydın, Kubilay; Yüksel, Çağrı; Ertekin, Erhan; Koyuncu, Ahmet

2016-01-01

In the present study, 24 nonmedicated patients with social anxiety disorder (SAD) were compared with 24 healthy control subjects to assess metabolite levels in the anterior cingulate, insula, caudate, and putamen using proton magnetic resonance spectroscopy. The ratio of N-acetylaspartate (NAA)/creatine (Cr) was significantly higher in patients with SAD than in healthy control subjects in the anterior cingulate and insula. NAA/Cr ratios in the insula correlated positively with the Liebowitz Social Anxiety Scale total scores in patients with SAD. Our results support the significance and biochemical involvement of the anterior cingulate and insula in the pathophysiology of SAD.

Locating Materials with Nuclear Quadrupole Moments within Surface Coil Array Area

DTIC Science & Technology

2015-08-11

location and dimension of the material can determined based on the nuclear quadrupole resonance ( NQR ) signal strength from the surface coil in the array...28.1MHz NQR frequency from potassium chlorate (PC) sample at room temperature. The PC sample will be in different locations parallel to the surface...using the experimental results from the dual surface coil array. 15. SUBJECT TERMS NQR , potassium chlorate, surface coil, surface probe, decoupling

Phosphorous31 magnetic resonance spectroscopy after total sleep deprivation in healthy adult men.

PubMed

Dorsey, Cynthia M; Lukas, Scott E; Moore, Constance M; Tartarini, Wendy L; Parow, Aimee M; Villafuerte, Rosemond A; Renshaw, Perry F

2003-08-01

To investigate chemical changes in the brains of healthy adults after sleep deprivation and recovery sleep, using phosphorous magnetic resonance spectroscopy. Three consecutive nights (baseline, sleep deprivation, recovery) were spent in the laboratory. Objective sleep measures were assessed on the baseline and recovery nights using polysomnography. Phosphorous magnetic resonance spectroscopy scans took place beginning at 7 am to 8 am on the morning after each of the 3 nights. Sleep laboratory in a private psychiatric teaching hospital. Eleven healthy young men. Following a baseline night of sleep, subjects underwent a night of total sleep deprivation, which involved supervision to ensure the absence of sleep but was not polysomnographically monitored. No significant changes in any measure of brain chemistry were observed the morning after a night of total sleep deprivation. However, after the recovery night, significant increases in total and beta-nucleoside triphosphate and decreases in phospholipid catabolism, measured by an increase in the concentration of glycerylphosphorylcholine, were observed. Chemical changes paralleled some changes in objective sleep measures. Significant chemical changes in the brain were observed following recovery sleep after 1 night of total sleep deprivation. The specific process underlying these changes is unclear due to the large brain region sampled in this exploratory study, but changes may reflect sleep inertia or some aspect of the homeostatic sleep mechanism that underlies the depletion and restoration of sleep. Phosphorous magnetic resonance spectroscopy is a technique that may be of value in further exploration of such sleep-wake functions.

Quanty for core level spectroscopy - excitons, resonances and band excitations in time and frequency domain

NASA Astrophysics Data System (ADS)

Haverkort, Maurits W.

2016-05-01

Depending on the material and edge under consideration, core level spectra manifest themselves as local excitons with multiplets, edge singularities, resonances, or the local projected density of states. Both extremes, i.e., local excitons and non-interacting delocalized excitations are theoretically well under control. Describing the intermediate regime, where local many body interactions and band-formation are equally important is a challenge. Here we discuss how Quanty, a versatile quantum many body script language, can be used to calculate a variety of different core level spectroscopy types on solids and molecules, both in the frequency as well as the time domain. The flexible nature of Quanty allows one to choose different approximations for different edges and materials. For example, using a newly developed method merging ideas from density renormalization group and quantum chemistry [1-3], Quanty can calculate excitons, resonances and band-excitations in x-ray absorption, photoemission, x-ray emission, fluorescence yield, non-resonant inelastic x-ray scattering, resonant inelastic x-ray scattering and many more spectroscopy types. Quanty can be obtained from: http://www.quanty.org.

Comparing localized and nonlocalized dynamic 31P magnetic resonance spectroscopy in exercising muscle at 7T

PubMed Central

Meyerspeer, Martin; Robinson, Simon; Nabuurs, Christine I; Scheenen, Tom; Schoisengeier, Adrian; Unger, Ewald; Kemp, Graham J; Moser, Ewald

2012-01-01

By improving spatial and anatomical specificity, localized spectroscopy can enhance the power and accuracy of the quantitative analysis of cellular metabolism and bioenergetics. Localized and nonlocalized dynamic 31P magnetic resonance spectroscopy using a surface coil was compared during aerobic exercise and recovery of human calf muscle. For localization, a short echo time single-voxel magnetic resonance spectroscopy sequence with adiabatic refocusing (semi-LASER) was applied, enabling the quantification of phosphocreatine, inorganic phosphate, and pH value in a single muscle (medial gastrocnemius) in single shots (TR = 6 s). All measurements were performed in a 7 T whole body scanner with a nonmagnetic ergometer. From a series of equal exercise bouts we conclude that: (a) with localization, measured phosphocreatine declines in exercise to a lower value (79 ± 7% cf. 53 ± 10%, P = 0.002), (b) phosphocreatine recovery shows shorter half time (t1/2 = 34 ± 7 s cf. t1/2 = 42 ± 7 s, nonsignificant) and initial postexercise phosphocreatine resynthesis rate is significantly higher (32 ± 5 mM/min cf. 17 ± 4 mM/min, P = 0.001) and (c) in contrast to nonlocalized 31P magnetic resonance spectroscopy, no splitting of the inorganic phosphate peak is observed during exercise or recovery, just an increase in line width during exercise. This confirms the absence of contaminating signals originating from weaker-exercising muscle, while an observed inorganic phosphate line broadening most probably reflects variations across fibers in a single muscle. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc. PMID:22334374

Broadband near-field mid-infrared spectroscopy and application to phonon resonances in quartz.

PubMed

Ishikawa, Michio; Katsura, Makoto; Nakashima, Satoru; Ikemoto, Yuka; Okamura, Hidekazu

2012-05-07

Infrared (IR) spectroscopy is a versatile analytical method and nano-scale spatial resolution could be achieved by scattering type near-field optical microscopy (s-SNOM). The spectral bandwidth was, however, limited to approximately 300 cm(-1) with a laser light source. In the present study, the development of a broadband mid-IR near-field spectroscopy with a ceramic light source is demonstrated. A much wider bandwidth (at least 3000 to 1000 cm(-1)) is achieved with a ceramic light source. The experimental data on quartz Si-O phonon resonance bands are well reproduced by theoretical simulations indicating the validity of the present broadband near-field IR spectroscopy.

Doubly resonant three-wave-mixing spectroscopy of a chiral coupled-chromophore system in solution: coherent two-dimensional optical activity spectroscopy.

PubMed

Cheon, Sangheon; Lee, Hochan; Choi, Jun-Ho; Cho, Minhaeng

2007-02-07

Theoretical descriptions of doubly resonant two-dimensional (2D) sum-frequency-generation (SFG) and difference-frequency-generation (DFG) spectroscopies of coupled-chromophore systems are presented. Despite that each electronic or vibrational chromophore is achiral, the interaction-induced chirality of a coupled multichromophore system in solution can be measured by using the doubly resonant 2D three-wave-mixing (3WM) spectroscopic method. An electronically coupled dimer, where each monomer is modeled as a simple two-level system, can have nonvanishing SFG (or DFG) properties, e.g., susceptibility in frequency domain or nonlinear response function in time domain, if the induced dipole vector of the dimer is not orthogonal to the vector product of the two monomer electronic transition dipole vectors. In order to demonstrate that these 2D 3WM spectroscopic methods can be used to determine the solution structure of a polypeptide, the authors carried out quantum chemistry calculations for an alanine dipeptide and obtained first- and second-order dipole derivatives associated with the amide I vibrational transitions of the dipeptide. It is shown that the numerically simulated 2D IR-IR SFG spectrum is highly sensitive to the dipeptide secondary structure and provides rich information on the one- and two-exciton states. It is believed that the theoretically proposed doubly resonant 2D 3WM spectroscopy, which can be considered to be an optical activity spectroscopy, will be of use in studying both structural and dynamical aspects of coupled multichromophore systems, such as proteins, nucleic acids, nanoparticle aggregates etc.

Quadrupole splittings in the near-infrared spectrum of 14NH 3

DOE PAGES

Twagirayezu, Sylvestre; Hall, Gregory E.; Sears, Trevor J.

2016-10-13

Sub-Doppler, saturation dip, spectra of lines in the v 1 + v 3, v 1 + 2v 4 and v 3 + 2v 4 bands of 14NH 3 have been measured by frequency comb-referenced diode laser absorption spectroscopy. The observed spectral line widths are dominated by transit time broadening, and show resolved or partially-resolved hyperfine splittings that are primarily determined by the 14N quadrupole coupling. Modeling of the observed line shapes based on the known hyperfine level structure of the ground state of the molecule shows that, in nearly all cases, the excited state level has hyperfine splittings similar tomore » the same rotational level in the ground state. The data provide accurate frequencies for the line positions and easily separate lines overlapped in Doppler-limited spectra. The observed hyperfine splittings can be used to make and confirm rotational assignments and ground state combination differences obtained from the measured frequencies are comparable in accuracy to those obtained from conventional microwave spectroscopy. Furthermore, several of the measured transitions do not show the quadrupole hyperfine splittings expected based on their existing rotational assignments. Either the assignments are incorrect or the upper levels involved are perturbed in a way that affects the nuclear hyperfine structure.« less

Magnetic resonance imaging and magnetic resonance spectroscopy for detection of early Alzheimer's disease.

PubMed

Westman, Eric; Wahlund, Lars-Olof; Foy, Catherine; Poppe, Michaela; Cooper, Allison; Murphy, Declan; Spenger, Christian; Lovestone, Simon; Simmons, Andrew

2011-01-01

Alzheimer's disease is the most common form of neurodegenerative disorder and early detection is of great importance if new therapies are to be effectively administered. We have investigated whether the discrimination between early Alzheimer's disease (AD) and elderly healthy control subjects can be improved by adding magnetic resonance spectroscopy (MRS) measures to magnetic resonance imaging (MRI) measures. In this study 30 AD patients and 36 control subjects were included. High resolution T1-weighted axial magnetic resonance images were obtained from each subject. Automated regional volume segmentation and cortical thickness measures were determined for the images. 1H MRS was acquired from the hippocampus and LCModel was used for metabolic quantification. Altogether, this yielded 58 different volumetric, cortical thickness and metabolite ratio variables which were used for multivariate analysis to distinguish between subjects with AD and Healthy controls. Combining MRI and MRS measures resulted in a sensitivity of 97% and a specificity of 94% compared to using MRI or MRS measures alone (sensitivity: 87%, 76%, specificity: 86%, 83% respectively). Adding the MRS measures to the MRI measures more than doubled the positive likelihood ratio from 6 to 17. Adding MRS measures to a multivariate analysis of MRI measures resulted in significantly better classification than using MRI measures alone. The method shows strong potential for discriminating between Alzheimer's disease and controls.

Resonance Raman Spectroscopy of Beta-Carotene and Lycopene: A Physical Chemistry Experiment.

ERIC Educational Resources Information Center

Hoskins, L. C.

1984-01-01

Discusses the theory of resonance Raman (RR) spectroscopy as it applies to beta-carotene and lycopene pigments (found in tomatoes and carrots, respectively). Also discusses an experiment which demonstrates the theoretical principles involved. The experiment has been tested over a three-year period and has received excellent acceptance by physical…

Brain aging: Evaluation of pH using phosphorus magnetic resonance spectroscopy.

PubMed

Cichocka, Monika; Kozub, Justyna; Urbanik, Andrzej

2018-02-02

Very important aspects of aging include age-related changes occurring in the brain. The aim of the present study was to identify the standard pH value in the entire brain volume using phosphorus magnetic resonance spectroscopy in healthy individuals of both sexes in different age groups, and then to determine whether there are differences in these values. A total of 65 individuals aged 20-32 years (mean age 24.5 ± 2.1 years, 31 women and 34 men) and 31 individuals aged 60-81 years (mean age 64.9 ± 5.5 years, 17 women and 14 men) were studied. The phosphorus magnetic resonance spectroscopy examination was carried out using a 1.5-T magnetic resonance system. The signal was acquired from the volume of interest that covered the whole brain. A vast majority of the examined individuals had slightly alkaline brain pH regardless of age. In the ≥20 years group, pH was 7.09 ± 0.11, and in the ≥60 years group, the average pH was 7.03 ± 0.05. This comparison of the pH identified in all the tested individuals shows a negative correlation of pH with age. The present findings might provide a valuable basis for further research into "healthy aging" as well as pathology in older adults. Geriatr Gerontol Int 2018; ••: ••-••. © 2018 Japan Geriatrics Society.

Nqrs Data for C24H76BLiN12O4P4 (Subst. No. 1593)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for C24H76BLiN12O4P4 (Subst. No. 1593)

Nuclear Magnetic Resonance Spectroscopy-Based Identification of Yeast.

PubMed

Himmelreich, Uwe; Sorrell, Tania C; Daniel, Heide-Marie

2017-01-01

Rapid and robust high-throughput identification of environmental, industrial, or clinical yeast isolates is important whenever relatively large numbers of samples need to be processed in a cost-efficient way. Nuclear magnetic resonance (NMR) spectroscopy generates complex data based on metabolite profiles, chemical composition and possibly on medium consumption, which can not only be used for the assessment of metabolic pathways but also for accurate identification of yeast down to the subspecies level. Initial results on NMR based yeast identification where comparable with conventional and DNA-based identification. Potential advantages of NMR spectroscopy in mycological laboratories include not only accurate identification but also the potential of automated sample delivery, automated analysis using computer-based methods, rapid turnaround time, high throughput, and low running costs.We describe here the sample preparation, data acquisition and analysis for NMR-based yeast identification. In addition, a roadmap for the development of classification strategies is given that will result in the acquisition of a database and analysis algorithms for yeast identification in different environments.

Time-resolved resonance fluorescence spectroscopy for study of chemical reactions in laser-induced plasmas.

PubMed

Liu, Lei; Deng, Leimin; Fan, Lisha; Huang, Xi; Lu, Yao; Shen, Xiaokang; Jiang, Lan; Silvain, Jean-François; Lu, Yongfeng

2017-10-30

Identification of chemical intermediates and study of chemical reaction pathways and mechanisms in laser-induced plasmas are important for laser-ablated applications. Laser-induced breakdown spectroscopy (LIBS), as a promising spectroscopic technique, is efficient for elemental analyses but can only provide limited information about chemical products in laser-induced plasmas. In this work, time-resolved resonance fluorescence spectroscopy was studied as a promising tool for the study of chemical reactions in laser-induced plasmas. Resonance fluorescence excitation of diatomic aluminum monoxide (AlO) and triatomic dialuminum monoxide (Al 2 O) was used to identify these chemical intermediates. Time-resolved fluorescence spectra of AlO and Al 2 O were used to observe the temporal evolution in laser-induced Al plasmas and to study their formation in the Al-O 2 chemistry in air.

Profiling planktonic biomass using element-specific, multicomponent nuclear magnetic resonance spectroscopy.

PubMed

Komatsu, Takanori; Kobayashi, Toshiya; Hatanaka, Minoru; Kikuchi, Jun

2015-06-02

Planktonic metabolism plays crucial roles in Earth's elemental cycles. Chemical speciation as well as elemental stoichiometry is important for advancing our understanding of planktonic roles in biogeochemical cycles. In this study, a multicomponent solid-state nuclear magnetic resonance (NMR) approach is proposed for chemical speciation of cellular components, using several advanced NMR techniques. Measurements by ssNMR were performed on (13)C and (15)N-labeled Euglena gracilis, a flagellated protist. 3D dipolar-assisted rotational resonance, double-cross-polarization (1)H-(13)C correlation spectroscopy, and (1)H-(13)C solid-state heteronuclear single quantum correlation spectroscopy successively allowed characterization of cellular components. These techniques were then applied to E. gracilis cultured in high and low ammonium media to demonstrate the power of this method for profiling and comparing cellular components. Cellular NMR spectra indicated that ammonium induced both paramylon degradation and amination. Arginine was stored as a nitrogen reserve and ammonium replaced by arginine catabolism via the arginine dihydrolase pathway. (15)N and (31)P cellular ssNMR indicated arginine and polyphosphate accumulation in E. gracilis, respectively. This chemical speciation technique will contribute to environmental research by providing detailed information on environmental chemical properties.

Surface Plasmon Resonance Sensors on Raman and Fluorescence Spectroscopy

PubMed Central

Wang, Jiangcai; Lin, Weihua; Cao, En; Xu, Xuefeng; Liang, Wenjie; Zhang, Xiaofang

2017-01-01

The performance of chemical reactions has been enhanced immensely with surface plasmon resonance (SPR)-based sensors. In this review, the principle and application of SPR sensors are introduced and summarized thoroughly. We introduce the mechanism of the SPR sensors and present a thorough summary about the optical design, including the substrate and excitation modes of the surface plasmons. Additionally, the applications based on SPR sensors are described by the Raman and fluorescence spectroscopy in plasmon-driven surface catalytic reactions and the measurement of refractive index sensing, especially. PMID:29212139

Resonant nonlinear ultrasound spectroscopy

DOEpatents

Johnson, Paul A.; TenCate, James A.; Guyer, Robert A.; Van Den Abeele, Koen E. A.

2001-01-01

Components with defects are identified from the response to strains applied at acoustic and ultrasound frequencies. The relative resonance frequency shift .vertline..DELTA..function./.function..sub.0.vertline., is determined as a function of applied strain amplitude for an acceptable component, where .function..sub.0 is the frequency of the resonance peak at the lowest amplitude of applied strain and .DELTA..function. is the frequency shift of the resonance peak of a selected mode to determine a reference relationship. Then, the relative resonance frequency shift .vertline..DELTA..function./.function..sub.0 is determined as a function of applied strain for a component under test, where fo .function..sub.0 the frequency of the resonance peak at the lowest amplitude of applied strain and .DELTA..function. is the frequency shift of the resonance peak to determine a quality test relationship. The reference relationship is compared with the quality test relationship to determine the presence of defects in the component under test.

Coherent Two-Dimensional Terahertz Magnetic Resonance Spectroscopy of Collective Spin Waves.

PubMed

Lu, Jian; Li, Xian; Hwang, Harold Y; Ofori-Okai, Benjamin K; Kurihara, Takayuki; Suemoto, Tohru; Nelson, Keith A

2017-05-19

We report a demonstration of two-dimensional (2D) terahertz (THz) magnetic resonance spectroscopy using the magnetic fields of two time-delayed THz pulses. We apply the methodology to directly reveal the nonlinear responses of collective spin waves (magnons) in a canted antiferromagnetic crystal. The 2D THz spectra show all of the third-order nonlinear magnon signals including magnon spin echoes, and 2-quantum signals that reveal pairwise correlations between magnons at the Brillouin zone center. We also observe second-order nonlinear magnon signals showing resonance-enhanced second-harmonic and difference-frequency generation. Numerical simulations of the spin dynamics reproduce all of the spectral features in excellent agreement with the experimental 2D THz spectra.

Magnetic resonance spectroscopy of the human brain.

PubMed

Ross, B; Bluml, S

2001-04-01

Magnetic resonance (MR; synonymous with NMR = nuclear magnetic resonance) is a universal physical technique best known for non-invasive detection and anatomical mapping of water protons (H). MR-spectroscopy (MRS) records protons from tissue chemicals other than water, intrinsic phosphorus containing metabolites, sodium, potassium, carbon, nitrogen, and fluorine. MRS is therefore an imaging technique with the potential to record human and animal biochemistry in vivo. As a result of wide availability of MRI equipment in research laboratories and hospitals, MRS is a serious competitor with PET to define normal body composition and its perturbation by pharmacological and pathological events. This article describes practical aspects of in vivo MRS with particular emphasis on the brain, where novel metabolites have been described. A survey of these new aspects of neurochemistry emphasize their practical utility as neuronal and axonal markers, measures of energy status, membrane constituents, and osmolytes, as well as some xenobiotics, such as alcohol. The concept of multinuclear in vivo MRS is illustrated by diagnosis and therapeutic monitoring of several human brain disorders. Although these methods are currently most frequently encountered in human studies, as well as with transgenic and knockout mouse models, MRS adds a new dimension to anatomic and histopathologic descriptions. Copyright 2001 Wiley-Liss, Inc.

Microwave spectroscopy of high-L, n=9 Rydberg levels of nickel: Polarizabilities and moments of the Ni+ ion

NASA Astrophysics Data System (ADS)

Woods, Shannon; Smith, Chris; Keele, Julie; Lundeen, S. R.

2013-02-01

The complete pattern of Rydberg binding energies of the 18 n=9 levels of nickel with L=6, 7, and 8 was measured using microwave plus resonant-excitation Stark-ionization spectroscopy. The measured pattern is consistent with the form predicted with the effective potential model, showing significant structure proportional to scalar products of tensor operators of order 0-4. The variation of the structure with L separates the various contributing terms and provides determinations of several properties of the Ni+ core ion. These include the quadrupole moment, Q = -0.469 78(9) a.u., the hexadecapole moment, Π = 0.36(5) a.u., the scalar and tensor dipole polarizabilities, αD,0= 7.949(2) a.u., αD,2=0.905(12) a.u., the scalar quadrupole polarizability, αQ,0=55(8) a.u., the g value, gJ=1.257(14), and the vector hyperpolarizability, βD,1=0.454(24) a.u.

Quadrupolar asymmetry in shifted-stem vane-shaped-rod radio frequency quadrupole accelerator

NASA Astrophysics Data System (ADS)

Mehrotra, Nitin

2018-04-01

Quadrupolar Asymmetry (QA), which has been a rampant problem for rod-type Radio Frequency Quadrupole (RFQ) Linacs, arises due to the geometry of resonant structure. A systematic parametric simulation study has been performed to unravel their effect on Figure of Merit (FoM) quantities namely Quality Factor (Q), Shunt Impedance (Rsh) and Quadrupolar Asymmetry (QA). A novel stem and cavity shape is proposed, which caters to the profile of electromagnetic fields of the resonant structure. A design methodology is formulated, which demonstrates that Quadrupolar Asymmetry can be annihilated, and a symmetric electric field can be produced in all four quadrants of rod-type RFQ accelerator.

Determination of molecular spectroscopic parameters and energy-transfer rates by double-resonance spectroscopy

NASA Technical Reports Server (NTRS)

Steinfeld, J. I.; Foy, B.; Hetzler, J.; Flannery, C.; Klaassen, J.; Mizugai, Y.; Coy, S.

1990-01-01

The spectroscopy of small to medium-size polyatomic molecules can be extremely complex, especially in higher-lying overtone and combination vibrational levels. The high density of levels also complicates the understanding of inelastic collision processes, which is required to model energy transfer and collision broadening of spectral lines. Both of these problems can be addressed by double-resonance spectroscopy, i.e., time-resolved pump-probe measurements using microwave, infrared, near-infrared, and visible-wavelength sources. Information on excited-state spectroscopy, transition moments, inelastic energy transfer rates and propensity rules, and pressure-broadening parameters may be obtained from such experiments. Examples are given for several species of importance in planetary atmospheres, including ozone, silane, ethane, and ammonia.

Computer simulation of magnetic resonance spectra employing homotopy.

PubMed

Gates, K E; Griffin, M; Hanson, G R; Burrage, K

1998-11-01

Multidimensional homotopy provides an efficient method for accurately tracing energy levels and hence transitions in the presence of energy level anticrossings and looping transitions. Herein we describe the application and implementation of homotopy to the analysis of continuous wave electron paramagnetic resonance spectra. The method can also be applied to electron nuclear double resonance, electron spin echo envelope modulation, solid-state nuclear magnetic resonance, and nuclear quadrupole resonance spectra. Copyright 1998 Academic Press.

Preliminary identification of unicellular algal genus by using combined confocal resonance Raman spectroscopy with PCA and DPLS analysis

NASA Astrophysics Data System (ADS)

He, Shixuan; Xie, Wanyi; Zhang, Ping; Fang, Shaoxi; Li, Zhe; Tang, Peng; Gao, Xia; Guo, Jinsong; Tlili, Chaker; Wang, Deqiang

2018-02-01

The analysis of algae and dominant alga plays important roles in ecological and environmental fields since it can be used to forecast water bloom and control its potential deleterious effects. Herein, we combine in vivo confocal resonance Raman spectroscopy with multivariate analysis methods to preliminary identify the three algal genera in water blooms at unicellular scale. Statistical analysis of characteristic Raman peaks demonstrates that certain shifts and different normalized intensities, resulting from composition of different carotenoids, exist in Raman spectra of three algal cells. Principal component analysis (PCA) scores and corresponding loading weights show some differences from Raman spectral characteristics which are caused by vibrations of carotenoids in unicellular algae. Then, discriminant partial least squares (DPLS) classification method is used to verify the effectiveness of algal identification with confocal resonance Raman spectroscopy. Our results show that confocal resonance Raman spectroscopy combined with PCA and DPLS could handle the preliminary identification of dominant alga for forecasting and controlling of water blooms.

One- and two-dimensional pulse electron paramagnetic resonance spectroscopy: concepts and applications.

PubMed

Van Doorslaer, S; Schweiger, A

2000-06-01

During the last two decades, the possibilities of pulse electron paramagnetic resonance (EPR) and pulse electron nuclear double resonance (ENDOR) spectroscopy have increased tremendously. While at the beginning of the 1980s pulse-EPR and ENDOR applications were still a rarity, the techniques are now very frequently applied in chemistry, physics, materials science, biology and mineralogy. This is mainly due to the considerable efforts invested in the last few years on instrument development and pulse-sequence design. Pulse-EPR spectrometers are now commercially available, which enables many research groups to use these techniques. In this work, an overview of state-of-the-art pulse EPR and ENDOR spectroscopy is given. The rapid expansion of the field, however, does not allow us to give an exhaustive record of all the pulse methods introduced so far. After a brief and very qualitative description of the basic principles of pulse EPR, we discuss some of the experiments in more detail and illustrate the potential of the methods with a number of selected applications.

Quantitative x-ray photoelectron spectroscopy: Quadrupole effects, shake-up, Shirley background, and relative sensitivity factors from a database of true x-ray photoelectron spectra

NASA Astrophysics Data System (ADS)

Seah, M. P.; Gilmore, I. S.

2006-05-01

An analysis is provided of the x-ray photoelectron spectroscopy (XPS) intensities measured in the National Physical Laboratory (NPL) XPS database for 46 solid elements. This present analysis does not change our previous conclusions concerning the excellent correlation between experimental intensities, following deconvolving the spectra with angle-averaged reflection electron energy loss data, and the theoretical intensities involving the dipole approximation using Scofield’s cross sections. Here, more recent calculations for cross sections by Trzhaskovskaya involving quadrupole terms are evaluated and it is shown that their cross sections diverge from the experimental database results by up to a factor of 5. The quadrupole angular terms lead to small corrections that are close to our measurement limit but do appear to be supported in the present analysis. Measurements of the extent of shake-up for the 46 elements broadly agree with the calculations of Yarzhemsky but not in detail. The predicted constancy in the shake-up contribution by Yarzhemsky implies that the use of the Shirley background will lead to a peak area that is a constant fraction of the true peak area including the shake-up intensities. However, the measured variability of the shake-up contribution makes the Shirley background invalid for quantification except for situations where the sensitivity factors are from reference samples similar to those being analyzed.

Deflecting light into resonant cavities for spectroscopy

DOEpatents

Zare, R.N.; Martin, J.; Paldus, B.A.

1998-09-29

Light is coupled into a cavity ring down spectroscopy (CRDS) resonant cavity using an acousto-optic modulator. The AOM allows in-coupling efficiencies in excess of 40%, which is two to three orders of magnitude higher than in conventional systems using a cavity mirror for in-coupling. The AOM shutoff time is shorter than the roundtrip time of the cavity. The higher light intensities lead to a reduction in shot noise, and allow the use of relatively insensitive but fast-responding detectors such as photovoltaic detectors. Other deflection devices such as electro-optic modulators or elements used in conventional Q-switching may be used instead of the AOM. The method is particularly useful in the mid-infrared, far-infrared, and ultraviolet wavelength ranges, for which moderately reflecting input mirrors are not widely available. 5 figs.

Deflecting light into resonant cavities for spectroscopy

DOEpatents

Zare, Richard N.; Martin, Juergen; Paldus, Barbara A.

1998-01-01

Light is coupled into a cavity ring down spectroscopy (CRDS) resonant cavity using an acousto-optic modulator. The AOM allows in-coupling efficiencies in excess of 40%, which is two to three orders of magnitude higher than in conventional systems using a cavity mirror for in-coupling. The AOM shutoff time is shorter than the roundtrip time of the cavity. The higher light intensities lead to a reduction in shot noise, and allow the use of relatively insensitive but fast-responding detectors such as photovoltaic detectors. Other deflection devices such as electro-optic modulators or elements used in conventional Q-switching may be used instead of the AOM. The method is particularly useful in the mid-infrared, far-infrared, and ultraviolet wavelength ranges, for which moderately reflecting input mirrors are not widely available.

Acupuncture therapy in treating migraine: results of a magnetic resonance spectroscopy imaging study.

PubMed

Gu, Tao; Lin, Lei; Jiang, Yun; Chen, Juan; D'Arcy, Ryan Cn; Chen, Min; Song, Xiaowei

2018-01-01

Acupuncture has been proven to be effective as an alternative therapy in treating migraine, but the pathophysiological mechanisms of the treatment remain unclear. This study investigated possible neurochemical responses to acupuncture treatment. Proton magnetic resonance spectroscopy imaging was used to investigate biochemical levels pre- and post-acupuncture treatment. Participants (N=45) included subjects diagnosed with: 1) migraine without aura; 2) cervicogenic headache; and 3) healthy controls. Participants in the two patient groups received verum acupuncture using acupoints that target migraine without aura but not cervicogenic headache, while the healthy controls received a sham treatment. All participants had magnetic resonance spectroscopy scans before and after the acupuncture therapy. Levels of brain metabolites were examined in relation to clinical headache assessment scores. A significant increase in N -acetylaspartate/creatine was observed in bilateral thalamus in migraine without aura after the acupuncture treatment, which was significantly correlated with the headache intensity score. The data demonstrate brain biochemical changes underlying the effect of acupuncture treatment of migraine.

Nqrs Data for H4I3Li2NO9 [H4INO3·2(ILiO3)] (Subst. No. 2278)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for H4I3Li2NO9 [H4INO3·2(ILiO3)] (Subst. No. 2278)

Nqrs Data for H6I3InO12 [I3InO9·3(H2O)] (Subst. No. 2289)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for H6I3InO12 [I3InO9·3(H2O)] (Subst. No. 2289)

A Vibrating Wire System For Quadrupole Fiducialization

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

Wolf, Zachary

2010-12-13

A vibrating wire system is being developed to fiducialize the quadrupoles between undulator segments in the LCLS. This note provides a detailed analysis of the system. The LCLS will have quadrupoles between the undulator segments to keep the electron beam focused. If the quadrupoles are not centered on the beam axis, the beam will receive transverse kicks, causing it to deviate from the undulator axis. Beam based alignment will be used to move the quadrupoles onto a straight line, but an initial, conventional alignment must place the quadrupole centers on a straight line to 100 {micro}m. In the fiducialization stepmore » of the initial alignment, the position of the center of the quadrupole is measured relative to tooling balls on the outside of the quadrupole. The alignment crews then use the tooling balls to place the magnet in the tunnel. The required error on the location of the quadrupole center relative to the tooling balls must be less than 25 {micro}m. In this note, we analyze a system under construction for the quadrupole fiducialization. The system uses the vibrating wire technique to position a wire onto the quadrupole magnetic axis. The wire position is then related to tooling balls using wire position detectors. The tooling balls on the wire position detectors are finally related to tooling balls on the quadrupole to perform the fiducialization. The total 25 {micro}m fiducialization error must be divided between these three steps. The wire must be positioned onto the quadrupole magnetic axis to within 10 {micro}m, the wire position must be measured relative to tooling balls on the wire position detectors to within 15 {micro}m, and tooling balls on the wire position detectors must be related to tooling balls on the quadrupole to within 10 {micro}m. The techniques used in these three steps will be discussed. The note begins by discussing various quadrupole fiducialization techniques used in the past and discusses why the vibrating wire technique is our

1H magnetic resonance spectroscopy in monocarboxylate transporter 8 gene deficiency.

PubMed

Sijens, Paul E; Rödiger, Lars A; Meiners, Linda C; Lunsing, Roelineke J

2008-05-01

In monocarboxylate transporter 8 (MCT8) gene deficiency, a syndrome combining thyroid and neurological abnormalities, the central nervous system has not yet been characterized by magnetic resonance (MR) spectroscopy. We studied whether the degree of dysmyelinization in MCT8 gene deficiency according to MR imaging (MRI) is coupled with abnormalities in brain metabolism. MRI and MR spectroscopy of the brain were performed twice in two MCT8 gene deficiency patients, for the first time at age 8-10 months and for the second time at age 17-28 months. The results were compared with those obtained in controls of a similar age. Compared with controls, young children with MCT8 show choline and myoinositol level increases and N-acetyl aspartate decreases in supraventricular gray and white matter, phenomena associated with the degree of dysmyelinization according to MRI. MCT8 gene deficiency results in deviant myelinization and general atrophy, which is substantiated by the MR spectroscopy findings of increased choline and myoinositol levels and decreased N-acetyl aspartate. The observations suggest that different mutations in the MCT8 gene lead to differences in the severity of the clinical spectrum, dysmyelinization, and MR spectroscopy-detectable changes in brain metabolism.

17O nuclear quadrupole coupling constants of water bound to a metal ion: A gadolinium(III) case study

NASA Astrophysics Data System (ADS)

Yazyev, Oleg V.; Helm, Lothar

2006-08-01

Rotational correlation times of metal ion aqua complexes can be determined from O17 NMR relaxation rates if the quadrupole coupling constant of the bound water oxygen-17 nucleus is known. The rotational correlation time is an important parameter for the efficiency of Gd3+ complexes as magnetic resonance imaging contrast agents. Using a combination of density functional theory with classical and Car-Parrinello molecular dynamics simulations we performed a computational study of the O17 quadrupole coupling constants in model aqua ions and the [Gd(DOTA)(H2O)]- complex used in clinical diagnostics. For the inner sphere water molecule in the [Gd(DOTA)(H2O)]- complex the determined quadrupole coupling parameter χ√1+η2/3 of 8.7MHz is very similar to that of the liquid water (9.0MHz ). Very close values were also predicted for the the homoleptic aqua ions of Gd3+ and Ca2+. We conclude that the O17 quadrupole coupling parameters of water molecules coordinated to closed shell and lanthanide metal ions are similar to water molecules in the liquid state.

Design of an rf quadrupole for Landau damping

NASA Astrophysics Data System (ADS)

Papke, K.; Grudiev, A.

2017-08-01

The recently proposed superconducting quadrupole resonator for Landau damping in accelerators is subjected to a detailed design study. The optimization process of two different cavity types is presented following the requirements of the High Luminosity Large Hadron Collider (HL-LHC) with the main focus on quadrupolar strength, surface peak fields, and impedance. The lower order and higher order mode (LOM and HOM) spectrum of the optimized cavities is investigated and different approaches for their damping are proposed. On the basis of an example the first two higher order multipole errors are calculated. Likewise on this example the required rf power and optimal external quality factor for the input coupler is derived.

1H magnetic resonance spectroscopy of invasive cervical cancer: an in vivo study with ex vivo corroboration.

PubMed

Mahon, Marrita M; Williams, Andreanna D; Soutter, W Patrick; Cox, I Jane; McIndoe, G Angus; Coutts, Glyn A; Dina, Roberto; deSouza, Nandita M

2004-02-01

The objective of this study was to establish in vivo (1)H-magnetic resonance (MR) spectroscopic appearances of cervical cancer using an endovaginal receiver coil and corroborate findings with magic angle spinning (MAS) MR spectroscopy of tissue samples. Fifty-three women (14 controls and 39 with cervical cancer) underwent endovaginal coil MR imaging at 1.5 T with T(1)- and T(2)-weighted scans sagittal and transverse to the cervix. Localized (1)H MR spectra (PRESS technique, TR 1600 ms, TE 135 ms) were accumulated in all controls and 29 cancer patients whose tumour filled > 50% of a single 3.4 cm(3) voxel. Peaks from triglyceride-CH(2) and -CH(3) were defined as present and in-phase (with the choline resonance), present but out-of-phase, or not present. Peak areas of choline-containing compounds were standardized to the area of unsuppressed tissue water resonance. Comparisons in observed resonances between groups were made using Fisher's exact test (qualitative data) and a t-test (quantitative data). Biopsies from these women analysed using MAS-MR spectroscopy and normalized to the intensity of an external standard of silicone rubber were similarly compared. Adequate water suppression permitted spectral analysis in 11 controls and 27 cancer patients. In-phase triglyceride-CH(2) resonances (1.3 ppm) were observed in 74% of tumours but in no control women (p < 0.001). No differences were observed in the presence of a 2 ppm resonance, choline-containing compounds or creatine in cancer compared with control women. However, ex vivo analysis showed significant differences not only in -CH(2), but also in -CH(3), a 2 ppm resonance, choline-containing compounds and creatine between tissues from control women and cancer tissue (p < 0.001, = 0.001, = 0.036, < 0.001 and = 0.004 respectively). On in vivo (1)H-MR spectroscopy, the presence of positive triglyceride-CH(2) resonances can be used to detect and confirm the presence of cervical cancer. However, technical improvements

A Tunable Reentrant Resonator with Transverse Orientation of Electric Field for in Vivo EPR Spectroscopy

NASA Astrophysics Data System (ADS)

Chzhan, Michael; Kuppusamy, Periannan; Samouilov, Alexandre; He, Guanglong; Zweier, Jay L.

1999-04-01

There has been a need for development of microwave resonator designs optimized to provide high sensitivity and high stability for EPR spectroscopy and imaging measurements ofin vivosystems. The design and construction of a novel reentrant resonator with transversely oriented electric field (TERR) and rectangular sample opening cross section for EPR spectroscopy and imaging ofin vivobiological samples, such as the whole body of mice and rats, is described. This design with its transversely oriented capacitive element enables wide and simple setting of the center frequency by trimming the dimensions of the capacitive plate over the range 100-900 MHz with unloadedQvalues of approximately 1100 at 750 MHz, while the mechanical adjustment mechanism allows smooth continuous frequency tuning in the range ±50 MHz. This orientation of the capacitive element limits the electric field based loss of resonatorQobserved with large lossy samples, and it facilitates the use of capacitive coupling. Both microwave performance data and EPR measurements of aqueous samples demonstrate high sensitivity and stability of the design, which make it well suited forin vivoapplications.

Research Applications of Magnetic Resonance Spectroscopy (MRS) to Investigate Psychiatric Disorders

PubMed Central

Dager, SR; Oskin, NM; Richards, TL; Posse, S

2009-01-01

Advances in magnetic resonance spectroscopy (MRS) methodology and related analytic strategies allow sophisticated testing of neurobiological models of disease pathology in psychiatric disorders. An overview of principles underlying MRS, methodological considerations and investigative approaches is presented. A review of recent research is presented that highlights innovative approaches applying MRS, in particular 1H MRS, to systematically investigate specific psychiatric disorders, including autism spectrum disorders, schizophrenia, panic disorder, major depression and bipolar disorder. PMID:19363431

Nqrs Data for C3H2Cl10N2PSb[C3HCl4N2P·Cl6HSb](Subst. No. 0601)

NASA Astrophysics Data System (ADS)

Chihara, H.; Nakamura, N.

This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C3H2Cl10N2PSb [C3HCl4N2P·Cl6HSb] (Subst. No. 0601)

Proton magnetic resonance spectroscopy for assessment of human body composition.

PubMed

Kamba, M; Kimura, K; Koda, M; Ogawa, T

2001-02-01

The usefulness of magnetic resonance spectroscopy (MRS)-based techniques for assessment of human body composition has not been established. We compared a proton MRS-based technique with the total body water (TBW) method to determine the usefulness of the former technique for assessment of human body composition. Proton magnetic resonance spectra of the chest to abdomen, abdomen to pelvis, and pelvis to thigh regions were obtained from 16 volunteers by using single, free induction decay measurement with a clinical magnetic resonance system operating at 1.5 T. The MRS-derived metabolite ratio was determined as the ratio of fat methyl and methylene proton resonance to water proton resonance. The peak areas for the chest to abdomen and the pelvis to thigh regions were normalized to an external reference (approximately 2200 g benzene) and a weighted average of the MRS-derived metabolite ratios for the 2 positions was calculated. TBW for each subject was determined by the deuterium oxide dilution technique. The MRS-derived metabolite ratios were significantly correlated with the ratio of body fat to lean body mass estimated by TBW. The MRS-derived metabolite ratio for the abdomen to pelvis region correlated best with the ratio of body fat to lean body mass on simple regression analyses (r = 0.918). The MRS-derived metabolite ratio for the abdomen to pelvis region and that for the pelvis to thigh region were selected for a multivariate regression model (R = 0.947, adjusted R(2) = 0.881). This MRS-based technique is sufficiently accurate for assessment of human body composition.

Klystron having electrostatic quadrupole focusing arrangement

DOEpatents

Maschke, Alfred W.

1983-08-30

A klystron includes a source for emitting at least one electron beam, and an accelerator for accelarating the beam in a given direction through a number of drift tube sections successively aligned relative to one another in the direction of the beam. A number of electrostatic quadrupole arrays are successively aligned relative to one another along at least one of the drift tube sections in the beam direction for focusing the electron beam. Each of the electrostatic quadrupole arrays forms a different quadrupole for each electron beam. Two or more electron beams can be maintained in parallel relationship by the quadrupole arrays, thereby enabling space charge limitations encountered with conventional single beam klystrons to be overcome.

Klystron having electrostatic quadrupole focusing arrangement

DOEpatents

Maschke, A.W.

1983-08-30

A klystron includes a source for emitting at least one electron beam, and an accelerator for accelerating the beam in a given direction through a number of drift tube sections successively aligned relative to one another in the direction of the beam. A number of electrostatic quadrupole arrays are successively aligned relative to one another along at least one of the drift tube sections in the beam direction for focusing the electron beam. Each of the electrostatic quadrupole arrays forms a different quadrupole for each electron beam. Two or more electron beams can be maintained in parallel relationship by the quadrupole arrays, thereby enabling space charge limitations encountered with conventional single beam klystrons to be overcome. 4 figs.

Temperature Measurements in Dynamically-loaded Systems Using Neutron Resonance Spectroscopy (NRS) at LANSCE

NASA Astrophysics Data System (ADS)

Yuan, V. W.

2002-12-01

In previous attempts to determine the internal temperature in systems subjected to dynamic loading, experimenters have usually relied on surface-based optical techniques that are often hampered by insufficient information regarding the emissivity of the surfaces under study. Neutron Resonance Spectroscopy (NRS) is a technique that uses Doppler-broadened neutron resonances to measure internal temperatures in dynamically-loaded samples. NRS has developed its own target-moderator assembly to provide single pulses with an order of magnitude higher brightness than the Lujan production target. The resonance line shapes from which temperature information is extracted are also influenced by non-temperature-dependent broadening from the moderator and detector phosphorescence. Dynamic NRS experiments have been performed to measure the temperature in a silver sheet jet and behind the passage of a shock wave in molybdenum.

Peptide backbone orientation and dynamics in spider dragline silk and two-photon excitation in nuclear magnetic and quadrupole resonance

NASA Astrophysics Data System (ADS)

Eles, Philip Thomas

2005-07-01

In the first part of the dissertation, spider dragline silk is studied by solid state NMR techniques. The dependence of NMR frequency on molecular orientation is exploited using the DECODER experiment to determine the orientation of the protein backbone within the silk fibre. Practical experimental considerations require that the silk fibres be wound about a cylindrical axis perpendicular to the external magnetic field, complicating the reconstruction of the underlying orientation distribution and necess-itating the development of numerical techniques for this purpose. A two-component model of silk incorporating static b-sheets and polyglycine II helices adequately fits the NMR data and suggests that the b-sheets are well aligned along the silk axis (20 FWHM) while the helices are poorly aligned (68 FWHM). The effects of fibre strain, draw rate and hydration on orientation are measured. Measurements of the time-scale for peptide backbone motion indicate that when wet, a strain-dependent frac-tion of the poorly aligned component becomes mobile. This suggests a mechanism for the supercontraction of silk involving latent entropic springs that undergo a local strain-dependent phase transition, driving supercontraction. In the second part of this dissertation a novel method is developed for exciting NMR and nuclear quadrupole resonance (NQR) by rf irradiation at multiple frequencies that sum to (or differ by) the resonance frequency. This is fundamentally different than traditional NMR experiments where irradiation is applied on-resonance. With excitation outside the detection bandwidth, two-photon excitation allows for detection of free induction signals during excitation, completely eliminating receiver dead-time. A theoretical approach to describing two-photon excitation is developed based on average Hamiltonian theory. An intuition for two-photon excitation is gained by analogy to the coherent absorption of multiple photons requiring conservation of total energy and

Discrete decoding based ultrafast multidimensional nuclear magnetic resonance spectroscopy

NASA Astrophysics Data System (ADS)

Wei, Zhiliang; Lin, Liangjie; Ye, Qimiao; Li, Jing; Cai, Shuhui; Chen, Zhong

2015-07-01

The three-dimensional (3D) nuclear magnetic resonance (NMR) spectroscopy constitutes an important and powerful tool in analyzing chemical and biological systems. However, the abundant 3D information arrives at the expense of long acquisition times lasting hours or even days. Therefore, there has been a continuous interest in developing techniques to accelerate recordings of 3D NMR spectra, among which the ultrafast spatiotemporal encoding technique supplies impressive acquisition speed by compressing a multidimensional spectrum in a single scan. However, it tends to suffer from tradeoffs among spectral widths in different dimensions, which deteriorates in cases of NMR spectroscopy with more dimensions. In this study, the discrete decoding is proposed to liberate the ultrafast technique from tradeoffs among spectral widths in different dimensions by focusing decoding on signal-bearing sites. For verifying its feasibility and effectiveness, we utilized the method to generate two different types of 3D spectra. The proposed method is also applicable to cases with more than three dimensions, which, based on the experimental results, may widen applications of the ultrafast technique.

Tailoring dielectric resonator geometries for directional scattering and Huygens’ metasurfaces

DOE PAGES

Campione, Salvatore; Basilio, Lorena I.; Warne, Larry K.; ...

2015-01-28

In this paper we describe a methodology for tailoring the design of metamaterial dielectric resonators, which represent a promising path toward low-loss metamaterials at optical frequencies. We first describe a procedure to decompose the far field scattered by subwavelength resonators in terms of multipolar field components, providing explicit expressions for the multipolar far fields. We apply this formulation to confirm that an isolated high-permittivity dielectric cube resonator possesses frequency separated electric and magnetic dipole resonances, as well as a magnetic quadrupole resonance in close proximity to the electric dipole resonance. We then introduce multiple dielectric gaps to the resonator geometrymore » in a manner suggested by perturbation theory, and demonstrate the ability to overlap the electric and magnetic dipole resonances, thereby enabling directional scattering by satisfying the first Kerker condition. We further demonstrate the ability to push the quadrupole resonance away from the degenerate dipole resonances to achieve local behavior. These properties are confirmed through the multipolar expansion and show that the use of geometries suggested by perturbation theory is a viable route to achieve purely dipole resonances for metamaterial applications such as wave-front manipulation with Huygens’ metasurfaces. Our results are fully scalable across any frequency bands where high-permittivity dielectric materials are available, including microwave, THz, and infrared frequencies.« less

Brain proton magnetic resonance spectroscopy for hepatic encephalopathy

NASA Astrophysics Data System (ADS)

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

1993-08-01

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

Key metabolites in tissue extracts of Elliptio complanata identified using 1H nuclear magnetic resonance spectroscopy

PubMed Central

Hurley-Sanders, Jennifer L.; Levine, Jay F.; Nelson, Stacy A. C.; Law, J. M.; Showers, William J.; Stoskopf, Michael K.

2015-01-01

We used 1H nuclear magnetic resonance spectroscopy to describe key metabolites of the polar metabolome of the freshwater mussel, Elliptio complanata. Principal components analysis documented variability across tissue types and river of origin in mussels collected from two rivers in North Carolina (USA). Muscle, digestive gland, mantle and gill tissues yielded identifiable but overlapping metabolic profiles. Variation in digestive gland metabolic profiles between the two mussel collection sites was characterized by differences in mono- and disaccharides. Variation in mantle tissue metabolomes appeared to be associated with sex. Nuclear magnetic resonance spectroscopy is a sensitive means to detect metabolites in the tissues of E. complanata and holds promise as a tool for the investigation of freshwater mussel health and physiology. PMID:27293708

Measurement of electron paramagnetic resonance using terahertz time-domain spectroscopy.

PubMed

Kozuki, Kohei; Nagashima, Takeshi; Hangyo, Masanori

2011-12-05

We present a frequency-domain electron spin resonance (ESR) measurement system using terahertz time-domain spectroscopy. A crossed polarizer technique is utilized to increase the sensitivity in detecting weak ESR signals of paramagnets caused by magnetic dipole transitions between magnetic sublevels. We demonstrate the measurements of ESR signal of paramagnetic copper(II) sulfate pentahydrate with uniaxial anisotropy of the g-factor under magnetic fields up to 10 T. The lineshape of the obtained ESR signals agrees well with the theoretical predictions for a powder sample with the uniaxial anisotropy.

A versatile pulse programmer for pulsed nuclear magnetic resonance spectroscopy.

NASA Technical Reports Server (NTRS)

Tarr, C. E.; Nickerson, M. A.

1972-01-01

A digital pulse programmer producing the standard pulse sequences required for pulsed nuclear magnetic resonance spectroscopy is described. In addition, a 'saturation burst' sequence, useful in the measurement of long relaxation times in solids, is provided. Both positive and negative 4 V trigger pulses are produced that are fully synchronous with a crystal-controlled time base, and the pulse programmer may be phase-locked with a maximum pulse jitter of 3 ns to the oscillator of a coherent pulse spectrometer. Medium speed TTL integrated circuits are used throughout.

Advanced Theory of Driven Birdcage Resonator with Losses for Biomedical Magnetic Resonance Imaging and Spectroscopy

PubMed Central

Novikov, Alexander

2010-01-01

A complete time-dependent physics theory of symmetric unperturbed driven Hybrid Birdcage resonator was developed for general application. In particular, the theory can be applied for RF coil engineering, computer simulations of coil-sample interaction, etc. Explicit time dependence is evaluated for different forms of driving voltage. The major steps of the solution development are shown and appropriate explanations are given. Green’s functions and spectral density formula were developed for any form of periodic driving voltage. The concept of distributed power losses based on transmission line theory is developed for evaluation of local losses of a coil. Three major types of power losses are estimated as equivalent series resistances in the circuit of the Birdcage resonator. Values of generated resistances in Legs and End-Rings are estimated. An application of the theory is shown for many practical cases. Experimental curve of B1 field polarization dependence is measured for eight-sections Birdcage coil. It was shown, that the steady-state driven resonance frequencies do not depend on damping factor unlike the free oscillation (transient) frequencies. An equivalent active resistance is generated due to interaction of RF electromagnetic field with a sample. Resistance of the conductor (enhanced by skin effect), Eddy currents and dielectric losses are the major types of losses which contribute to the values of generated resistances. A biomedical sample for magnetic resonance imaging and spectroscopy is the source of the both Eddy current and dielectric losses of a coil. As demonstrated by the theory, Eddy currents losses is the major effect of coil shielding. PMID:20869184

Acupuncture therapy in treating migraine: results of a magnetic resonance spectroscopy imaging study

PubMed Central

Gu, Tao; Lin, Lei; Jiang, Yun; Chen, Juan; D’Arcy, Ryan CN; Chen, Min; Song, Xiaowei

2018-01-01

Background Acupuncture has been proven to be effective as an alternative therapy in treating migraine, but the pathophysiological mechanisms of the treatment remain unclear. This study investigated possible neurochemical responses to acupuncture treatment. Patients and methods Proton magnetic resonance spectroscopy imaging was used to investigate biochemical levels pre- and post-acupuncture treatment. Participants (N=45) included subjects diagnosed with: 1) migraine without aura; 2) cervicogenic headache; and 3) healthy controls. Participants in the two patient groups received verum acupuncture using acupoints that target migraine without aura but not cervicogenic headache, while the healthy controls received a sham treatment. All participants had magnetic resonance spectroscopy scans before and after the acupuncture therapy. Levels of brain metabolites were examined in relation to clinical headache assessment scores. Results A significant increase in N-acetylaspartate/creatine was observed in bilateral thalamus in migraine without aura after the acupuncture treatment, which was significantly correlated with the headache intensity score. Conclusion The data demonstrate brain biochemical changes underlying the effect of acupuncture treatment of migraine. PMID:29740217

Angle-dependent spin-wave resonance spectroscopy of (Ga,Mn)As films

NASA Astrophysics Data System (ADS)

Dreher, L.; Bihler, C.; Peiner, E.; Waag, A.; Schoch, W.; Limmer, W.; Goennenwein, S. T. B.; Brandt, M. S.

2013-06-01

A modeling approach for standing spin-wave resonances based on a finite-difference formulation of the Landau-Lifshitz-Gilbert equation is presented. In contrast to a previous study [C. Bihler , Phys. Rev. BPRBMDO1098-012110.1103/PhysRevB.79.045205 79, 045205 (2009)], this formalism accounts for elliptical magnetization precession and magnetic properties arbitrarily varying across the layer thickness, including the magnetic anisotropy parameters, the exchange stiffness, the Gilbert damping, and the saturation magnetization. To demonstrate the usefulness of our modeling approach, we experimentally study a set of (Ga,Mn)As samples grown by low-temperature molecular-beam epitaxy by means of angle-dependent standing spin-wave resonance spectroscopy and electrochemical capacitance-voltage measurements. By applying our modeling approach, the angle dependence of the spin-wave resonance data can be reproduced in a simulation with one set of simulation parameters for all external field orientations. We find that the approximately linear gradient in the out-of-plane magnetic anisotropy is related to a linear gradient in the hole concentrations of the samples.

Gas hydrate property measurements in porous sediments with resonant ultrasound spectroscopy

NASA Astrophysics Data System (ADS)

McGrail, B. P.; Ahmed, S.; Schaef, H. T.; Owen, A. T.; Martin, P. F.; Zhu, T.

2007-05-01

Resonant ultrasound spectroscopy was used to characterize a natural geological core sample obtained from the Mallik 5L-38 gas hydrate research well at high pressure and subambient temperatures. Using deuterated methane gas to form gas hydrate in the core sample, it was discovered that resonance amplitudes are correlated with the fraction of the pore space occupied by the gas hydrate crystals. A pore water freezing model was developed that utilizes the known pore size distribution and pore water chemistry to predict gas hydrate saturation as a function of pressure and temperature. The model showed good agreement with the experimental measurements and demonstrated that pore water chemistry is the most important factor controlling equilibrium gas hydrate saturations in these sediments when gas hydrates are formed artificially in laboratory pressure vessels. With further development, the resonant ultrasound technique can provide a rapid, nondestructive, field portable means of measuring the equilibrium P-T properties and dissociation kinetics of gas hydrates in porous media, determining gas hydrate saturations, and may provide new insights into the nature of gas hydrate formation mechanisms in geologic materials.

Barium Tagging from nEXO Using Resonance Ionization Spectroscopy

NASA Astrophysics Data System (ADS)

Twelker, K.; Kravitz, S.

nEXO is a 5-ton liquid enriched-xenon time projection chamber (TPC) to search for neutrinoless double-beta decay, designed to have the sensitivity to completely probe the inverted mass hierarchy of Majorana neutrinos. The detector will accommodate-as a background reduction technique-a system to recover and identify the barium decay product. This upgrade will allow a background-free measurement of neutrinoless double-beta decay and increase the half-life sensitivity of the experiment by at least one order of magnitude. Ongoing research and development includes a system to test barium extraction from liquid xenon using surface adsorption and Resonance Ionization Spectroscopy (RIS).

Gravity resonance spectroscopy constrains dark energy and dark matter scenarios.

PubMed

Jenke, T; Cronenberg, G; Burgdörfer, J; Chizhova, L A; Geltenbort, P; Ivanov, A N; Lauer, T; Lins, T; Rotter, S; Saul, H; Schmidt, U; Abele, H

2014-04-18

We report on precision resonance spectroscopy measurements of quantum states of ultracold neutrons confined above the surface of a horizontal mirror by the gravity potential of Earth. Resonant transitions between several of the lowest quantum states are observed for the first time. These measurements demonstrate that Newton's inverse square law of gravity is understood at micron distances on an energy scale of 10-14  eV. At this level of precision, we are able to provide constraints on any possible gravitylike interaction. In particular, a dark energy chameleon field is excluded for values of the coupling constant β>5.8×108 at 95% confidence level (C.L.), and an attractive (repulsive) dark matter axionlike spin-mass coupling is excluded for the coupling strength gsgp>3.7×10-16 (5.3×10-16) at a Yukawa length of λ=20  μm (95% C.L.).

Reduced posterior cingulate glutamate measured by magnetic resonance spectroscopy in hyperthyroidism.

PubMed

Liu, Xinxin; Bai, Zhilan; Liu, Feng; Li, Min; Zhang, Qiujuan; Song, Guangyi; Xu, Jing

2012-01-01

Patients with hyperthyroidism frequently have neuropsychiatric complaints such as lack of concentration, poor performance in memory, depression, anxiety and mania. These symptoms suggest the dysfunction of brain. However, the underlying process of this dysfunction is not well understood. At the same time, glutamatergic system has been considered important in neuropsychiatric process by recent studies. Thus, this study is to investigate the change of glutamate concentration in patients with hyperthyroidism using proton magnetic resonance spectroscopy. Fifteen untreated patients with hyperthyroidism and fifteen age- and gender- matched controls participated in the study. The region of the posterior cingulate cortex was examined by magnetic resonance spectroscopy with a technique referred as TE-averaged PRESS at 3T field strength. The concentrations of N-Acetylaspartate, creatine, choline and glutamate were assessed using jMRUI v4.0 software. Hyperthyroid patients, compared with controls, showed a decrease of glutamate concentration (P<0.047) and glutamate/creatine ratios (P<0.009) in the posterior cingulate cortex. The decrease of choline concentration (P<0.004) and choline/creatine ratios (P<0.012) were also discovered. No significant difference was found in the concentrations of N-Acetylaspartate or creatine between patients and controls. Concentration of glutamate decreased in the region of posterior cingulate cortex in patients with hyperthyroidism. This reduction indicated a possible involvement of glutamate in the brain dysfunction in hyperthyroidism.

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

ERIC Educational Resources Information Center

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

2012-01-01

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

An electronically tuned wideband probehead for NQR spectroscopy in the VHF range

NASA Astrophysics Data System (ADS)

Scharfetter, Hermann

2016-10-01

Nuclear quadrupole resonance spectroscopy is an analytical method which allows to characterize materials which contain quadrupolar nuclei, i.e. nuclei with spin ⩾1. The measurement technology is similar to that of NMR except that no static magnetic field is necessary. In contrast to NMR, however, it is frequently necessary to scan spectra with a very large bandwidth with a span of several tens of % of the central frequency so as to localize unknown peaks. Standard NMR probeheads which are typically constructed as resonators must be tuned and matched to comparatively narrow bands and must thus be re-tuned and re-matched very frequently when scanning over a whole NQR spectrum. At low frequencies up to few MHz dedicated circuits without the need for tuning and matching have been developed, but many quadrupole nuclei have transitions in the VHF range between several tens of MHz up to several hundreds of MHz. Currently available commercial NQR probeheads employ stepper motors for setting mechanically tuneable capacitors in standard NMR resonators. These yield high quality factors (Q) and thus high SNR but are relatively large and clumsy and do not allow for fast frequency sweeps. This article presents a new concept for a NQR probehead which combines a previously published no-tune no-match wideband concept for the transmit (TX) pulse with an electronically tuneable receive (RX) part employing varactor diodes. The prototype coil provides a TX frequency range of 57 MHz with a center frequency of 97.5 MHz with a return loss of ⩽-15 dB. During RX the resonator is tuned and matched automatically to the right frequency via control voltages which are read out from a previously generated lookup table, thus providing high SNR. The control voltages which bias the varactors settle very fast and allow for hopping to the next frequency point in the spectrum within less than 100 μs. Experiments with a test sample of ZnBr2 proved the feasibility of the method.

Using resonance light scattering and UV/vis absorption spectroscopy to study the interaction between gliclazide and bovine serum albumin.

PubMed

Zhang, Qiu-Ju; Liu, Bao-Sheng; Li, Gai-Xia; Han, Rong

2016-08-01

At different temperatures (298, 310 and 318 K), the interaction between gliclazide and bovine serum albumin (BSA) was investigated using fluorescence quenching spectroscopy, resonance light scattering spectroscopy and UV/vis absorption spectroscopy. The first method studied changes in the fluorescence of BSA on addition of gliclazide, and the latter two methods studied the spectral change in gliclazide while BSA was being added. The results indicated that the quenching mechanism between BSA and gliclazide was static. The binding constant (Ka ), number of binding sites (n), thermodynamic parameters, binding forces and Hill's coefficient were calculated at three temperatures. Values for the binding constant obtained using resonance light scattering and UV/vis absorption spectroscopy were much greater than those obtained from fluorescence quenching spectroscopy, indicating that methods monitoring gliclazide were more accurate and reasonable. In addition, the results suggest that other residues are involved in the reaction and the mode 'point to surface' existed in the interaction between BSA and gliclazide. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Amplitude quantification in contact-resonance-based voltage-modulated force spectroscopy

NASA Astrophysics Data System (ADS)

Bradler, Stephan; Schirmeisen, André; Roling, Bernhard

2017-08-01

Voltage-modulated force spectroscopy techniques, such as electrochemical strain microscopy and piezoresponse force microscopy, are powerful tools for characterizing electromechanical properties on the nanoscale. In order to correctly interpret the results, it is important to quantify the sample motion and to distinguish it from the electrostatic excitation of the cantilever resonance. Here, we use a detailed model to describe the cantilever dynamics in contact resonance measurements, and we compare the results with experimental values. We show how to estimate model parameters from experimental values and explain how they influence the sensitivity of the cantilever with respect to the excitation. We explain the origin of different crosstalk effects and how to identify them. We further show that different contributions to the measured signal can be distinguished by analyzing the correlation between the resonance frequency and the measured amplitude. We demonstrate this technique on two representative test samples: (i) ferroelectric periodically poled lithium niobate, and (ii) the Na+-ion conducting soda-lime float glass. We extend our analysis to higher cantilever bending modes and show that non-local electrostatic excitation is strongly reduced in higher bending modes due to the nodes in the lever shape. Based on our analyses, we present practical guidelines for quantitative imaging.

The fast Padé transform in magnetic resonance spectroscopy for potential improvements in early cancer diagnostics

NASA Astrophysics Data System (ADS)

Belkic, Dzevad; Belkic, Karen

2005-09-01

The convergence rates of the fast Padé transform (FPT) and the fast Fourier transform (FFT) are compared. These two estimators are used to process a time-signal encoded at 4 T by means of one-dimensional magnetic resonance spectroscopy (MRS) for healthy human brain. It is found systematically that at any level of truncation of the full signal length, the clinically relevant resonances that determine concentrations of metabolites in the investigated tissue are significantly better resolved in the FPT than in the FFT. In particular, the FPT has a better resolution than the FFT for the same signal length. Moreover, the FPT can achieve the same resolution as the FFT by using twice shorter signals. Implications of these findings for two-dimensional magnetic resonance spectroscopy as well as for two- and three-dimensional magnetic resonance spectroscopic imaging are highlighted. Self-contained cross-validation of all the results from the FPT is secured by using two conceptually different, equivalent algorithms (inside and outside the unit-circle), that are both valid in the entire complex frequency plane. The difference between the results from these two variants of the FPT is indistinguishable from the background noise. This constitutes robust error analysis of proven validity. The FPT shows promise in applications of MRS for early cancer detection.

Characterizing millisecond intermediates in hemoproteins using rapid-freeze-quench resonance Raman spectroscopy.

PubMed

Matsumura, Hirotoshi; Moënne-Loccoz, Pierre

2014-01-01

The combination of rapid freeze quenching (RFQ) with resonance Raman (RR) spectroscopy represents a unique tool with which to investigate the nature of short-lived intermediates formed during the enzymatic reactions of metalloproteins. Commercially available equipment allows trapping of intermediates within a millisecond to second time scale for low-temperature RR analysis resulting in the direct detection of metal-ligand vibrations and porphyrin skeletal vibrations in hemoproteins. This chapter briefly discusses RFQ-RR studies carried out previously in our laboratory and presents, as a practical example, protocols for the preparation of RFQ samples of the reaction of metmyoglobin with nitric oxide (NO) under anaerobic conditions. Also described are important controls and practical procedures for the analysis of these samples by low-temperature RR spectroscopy.

Magnetic Resonance Spectroscopy (MRS) of Prostatic Fluids for Early Detection of Prostate Cancer

DTIC Science & Technology

2006-10-01

nuclear magnetic resonance spectroscopy (1H-NMRS). The metabolites quantified included citrate, spermine, myo- inositol , lactate, alanine...adjusting for age. The LR models indicated that the absolute concentrations of citrate, myo- inositol , and spermine were highly predictive of PCa and...inversely related to the risk of PCa. The areas under the receiver operating characteristic curves (AUROC) for citrate, myo- inositol and spermine were

Metabolic assessment of the action of targeted cancer therapeutics using magnetic resonance spectroscopy

PubMed Central

Beloueche-Babari, M; Chung, Y-L; Al-Saffar, N M S; Falck-Miniotis, M; Leach, M O

2009-01-01

Developing rational targeted cancer drugs requires the implementation of pharmacodynamic (PD), preferably non-invasive, biomarkers to aid response assessment and patient follow-up. Magnetic resonance spectroscopy (MRS) allows the non-invasive study of tumour metabolism. We describe the MRS-detectable PD biomarkers resulting from the action of targeted therapeutics, and discuss their biological significance and future translation into clinical use. PMID:19935796

Fast Electron Spectroscopy of Enhanced Plasmonic N anoantenna Resonances

NASA Astrophysics Data System (ADS)

Day, Jared K.

Surface plasmons are elementary excitations of the collective and coherent oscillations of conductive band electrons coupled with photons at the surface of metals. Surface plasmons of metallic nanostructures can efficiently couple to light making them a new class of optical antennas that can confine and control light at nanometer scale dimensions. Nanoscale optical antennas can be used to enhance the energy transfer between nanoscale systems and freely-propagating radiation. Plasmonic nanoantennas have already been used to enhance single molecule detection, diagnosis and treat cancer, harvest solar energy, to create metamaterials with new optical properties and to enhance photo-chemical reactions. The applications for plasmonic nanoantennas are only limited by the fundamental understanding of their unique optical properties and the rational design of new coupled antenna systems. It is therefore necessary to interrogate and image the local electromagnetic response of nanoantenna systems to establish intuition between near-field coupling dynamics and far-field optical properties. This thesis focuses on the characterization and enhancement of the longitudinal multipolar plasmonic resonances of Au nanorod nanoantennas. To better understand these resonances fast electron spectroscopy is used to both visualize and probe the near- and far-field properties of multipolar resonances of individual nanorods and more complex nanorod systems through cathodoluminescence (CL). CL intensity maps show that coupled nanorod systems enhance and alter nanorod resonances away from ideal resonant behavior creating hybridized longitudinal modes that expand and relax at controllable locations along the nanorod. These measurements show that complex geometries can strengthen and alter the local density of optical states for nanoantenna designs with more functionality and better control of localized electromagnetic fields. Finally, the electron excitations are compared to plane wave optical

Neuronavigation using three-dimensional proton magnetic resonance spectroscopy data.

PubMed

Kanberoglu, Berkay; Moore, Nina Z; Frakes, David; Karam, Lina J; Debbins, Josef P; Preul, Mark C

2014-01-01

Applications in clinical medicine can benefit from fusion of spectroscopy data with anatomical imagery. For example, new 3-dimensional (3D) spectroscopy techniques allow for improved correlation of metabolite profiles with specific regions of interest in anatomical tumor images, which can be useful in characterizing and treating heterogeneous tumors that appear structurally homogeneous. We sought to develop a clinical workflow and uniquely capable custom software tool to integrate advanced 3-tesla 3D proton magnetic resonance spectroscopic imaging ((1)H-MRSI) into industry standard image-guided neuronavigation systems, especially for use in brain tumor surgery. (1)H-MRSI spectra from preoperative scanning on 15 patients with recurrent or newly diagnosed meningiomas were processed and analyzed, and specific voxels were selected based on their chemical contents. 3D neuronavigation overlays were then generated and applied to anatomical image data in the operating room. The proposed 3D methods fully account for scanner calibration and comprise tools that we have now made publicly available. The new methods were quantitatively validated through a phantom study and applied successfully to mitigate biopsy uncertainty in a clinical study of meningiomas. The proposed methods improve upon the current state of the art in neuronavigation through the use of detailed 3D (1)H-MRSI data. Specifically, 3D MRSI-based overlays provide comprehensive, quantitative visual cues and location information during neurosurgery, enabling a progressive new form of online spectroscopy-guided neuronavigation. © 2014 S. Karger AG, Basel.

Characterization of CuHal-intercalated carbon nanotubes with x-ray absorption spectroscopy combined with x-ray photoelectron and resonant photoemission spectroscopies

NASA Astrophysics Data System (ADS)

Brzhezinskaya, M.; Generalov, A.; Vinogdradov, A.; Eliseev, A.

2013-04-01

Encapsulated single-walled carbon nanotubes (SWCNTs) with inner channels filled by different compounds present the new class of composite materials. Such CNTs give opportunity to form 1D nanocrystals as well as quantum nanowires with new physical and chemical properties inside the tubes. The present study is aimed to characterize the possible chemical interaction between CuHal (Hal=I, Cl, Br) and SWCNTs in CuHal@SWCNTs and electronic structure of the latter using high-resolution near edge X-ray absorption fine structure (NEXAFS) spectroscopy combined with high-resolution X-ray photoelectron spectroscopy and resonant photoemission spectroscopy. The present study has shown that there is a chemical interaction between the filler and π-electron subsystem of CNTs which is accompanied by changes of the atomic and electronic structure of the filler during the encapsulating it inside CNTs.

Localized one-dimensional single voxel magnetic resonance spectroscopy without J coupling modulations.

PubMed

Lin, Yanqin; Lin, Liangjie; Wei, Zhiliang; Zhong, Jianhui; Chen, Zhong

2016-12-01

To acquire single voxel localized one-dimensional 1 H magnetic resonance spectroscopy (MRS) without J coupling modulations, free from amplitude and phase distortions. A pulse sequence, named PRESSIR, is developed for volume localized MRS without J modulations at arbitrary echo time (TE). The J coupling evolution is suppressed by the J-refocused module that uses a 90° pulse at the midpoint of a double spin echo. The localization performance of the PRESSIR sequence was tested with a two-compartment phantom. The proposed sequence shows similar voxel localization accuracy as PRESS. Both PRESSIR and PRESS sequences were performed on MRS brain phantom and pig brain tissue. PRESS spectra suffer from amplitude and phase distortions due to J modulations, especially under moderate and long TEs, while PRESSIR spectra are almost free from distortions. The PRESSIR sequence proposed herein enables the acquisition of single voxel in-phase MRS within a single scan. It allows an enhanced signal intensity of J coupling metabolites and reducing undesired broad resonances with short T2s while suppressing J modulations. Moreover, it provides an approach for direct measurement of nonoverlapping J coupling peaks and of transverse relaxation times T2s. Magn Reson Med 76:1661-1667, 2016. © 2015 International Society for Magnetic Resonance in Medicine. © 2015 International Society for Magnetic Resonance in Medicine.

Laser spectroscopy of the 5P3/2 → 6Pj (j = 1/2 and 3/2) electric dipole forbidden transitions in atomic rubidium

NASA Astrophysics Data System (ADS)

Ponciano-Ojeda, F.; Hernández-Gómez, S.; Mojica-Casique, C.; Hoyos, L. M.; Flores-Mijangos, J.; Ramírez-Martínez, F.; Sahagún, D.; Jáuregui, R.; Jiménez-Mier, J.

2018-04-01

Doppler-free optical double-resonance spectroscopy is used to study the 5S1/2 → 5P3/2 → 6Pj (j = 3/2,1/2) excitation sequence in room-temperature rubidium atoms. This involves a 5S1/2 → 5P3/2 electric dipole preparation step followed by the 5P3/2 → 6Pj electric quadrupole excitation. The electric dipole forbidden transitions occur at 911.0 nm (j = 3/2) and 917.5 nm (j = 1/2). Production of atoms in the 6Pj states is detected by observing their direct decay to the ground state through emission of blue photons (λ ≈ 420 nm). A detailed experimental and theoretical study of the dependence on the relative linear polarizations of excitation beams is made. It is shown that specific electric quadrupole selection rules over magnetic quantum numbers are directly related to the relative orientation of the linear polarization of the excitation beams.

Spectroscopy of baryon resonances

NASA Astrophysics Data System (ADS)

Beck, Reinhard; Thoma, Ulrike

2017-01-01

Within project A.1 of the SFB/TR16 "Subnuclear Structure of Matter", a large amount of data on photoproduction reactions has been accumulated at the Bonn Electron Stretcher Accelerator ELSA with the CBELSA/TAPS detector and was analysed in detail. In particular, data have been taken with unpolarized or with linearly or circularly polarized photons and with unpolarized or with longitudinally or transversely polarized protons. Photoproduction off neutrons was studied to determine the helicity amplitudes for the excitation of resonances off neutrons. In a partial wave analysis of the data, new resonances have been found and the properties of new and of known resonances have been determined, including the measurement of partial widths of so far unmeasured decay modes.

Cavity-enhanced resonant photoacoustic spectroscopy with optical feedback cw diode lasers: A novel technique for ultratrace gas analysis and high-resolution spectroscopy.

PubMed

Hippler, Michael; Mohr, Christian; Keen, Katherine A; McNaghten, Edward D

2010-07-28

Cavity-enhanced resonant photoacoustic spectroscopy with optical feedback cw diode lasers (OF-CERPAS) is introduced as a novel technique for ultratrace gas analysis and high-resolution spectroscopy. In the scheme, a single-mode cw diode laser (3 mW, 635 nm) is coupled into a high-finesse linear cavity and stabilized to the cavity by optical feedback. Inside the cavity, a build-up of laser power to at least 2.5 W occurs. Absorbing gas phase species inside the cavity are detected with high sensitivity by the photoacoustic effect using a microphone embedded in the cavity. To increase sensitivity further, coupling into the cavity is modulated at a frequency corresponding to a longitudinal resonance of an organ pipe acoustic resonator (f=1.35 kHz and Q approximately 10). The technique has been characterized by measuring very weak water overtone transitions near 635 nm. Normalized noise-equivalent absorption coefficients are determined as alpha approximately 4.4x10(-9) cm(-1) s(1/2) (1 s integration time) and 2.6x10(-11) cm(-1) s(1/2) W (1 s integration time and 1 W laser power). These sensitivities compare favorably with existing state-of-the-art techniques. As an advantage, OF-CERPAS is a "zero-background" method which increases selectivity and sensitivity, and its sensitivity scales with laser power.

Magnetic Resonance Spectroscopy (MRS) of Prostatic Fluids for Early Detection of Prostate Cancer

DTIC Science & Technology

2007-04-01

quantitative proton nuclear magnetic resonance spectroscopy (1H-NMRS). The metabolites quantified included citrate, spermine, myo- inositol , lactate, alanine...concentrations while adjusting for age. The LR models indicated that the absolute concentrations of citrate, myo- inositol , and spermine were highly predictive...of PCa and inversely related to the risk of PCa. The areas under the receiver operating characteristic curves (AUROC) for citrate, myo- inositol and

Permanent magnet edge-field quadrupole

DOEpatents

Tatchyn, Roman O.

1997-01-01

Planar permanent magnet edge-field quadrupoles for use in particle accelerating machines and in insertion devices designed to generate spontaneous or coherent radiation from moving charged particles are disclosed. The invention comprises four magnetized rectangular pieces of permanent magnet material with substantially similar dimensions arranged into two planar arrays situated to generate a field with a substantially dominant quadrupole component in regions close to the device axis.

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

PubMed Central

Sörös, Peter; Michael, Nikolaus; Tollkötter, Melanie; Pfleiderer, Bettina

2006-01-01

Background A combination of magnetoencephalography and proton magnetic resonance spectroscopy was used to correlate the electrophysiology of rapid auditory processing and the neurochemistry of the auditory cortex in 15 healthy adults. To assess rapid auditory processing in the left auditory cortex, the amplitude and decrement of the N1m peak, the major component of the late auditory evoked response, were measured during rapidly successive presentation of acoustic stimuli. We tested the hypothesis that: (i) the amplitude of the N1m response and (ii) its decrement during rapid stimulation are associated with the cortical neurochemistry as determined by proton magnetic resonance spectroscopy. Results Our results demonstrated a significant association between the concentrations of N-acetylaspartate, a marker of neuronal integrity, and the amplitudes of individual N1m responses. In addition, the concentrations of choline-containing compounds, representing the functional integrity of membranes, were significantly associated with N1m amplitudes. No significant association was found between the concentrations of the glutamate/glutamine pool and the amplitudes of the first N1m. No significant associations were seen between the decrement of the N1m (the relative amplitude of the second N1m peak) and the concentrations of N-acetylaspartate, choline-containing compounds, or the glutamate/glutamine pool. However, there was a trend for higher glutamate/glutamine concentrations in individuals with higher relative N1m amplitude. Conclusion These results suggest that neuronal and membrane functions are important for rapid auditory processing. This investigation provides a first link between the electrophysiology, as recorded by magnetoencephalography, and the neurochemistry, as assessed by proton magnetic resonance spectroscopy, of the auditory cortex. PMID:16884545

High-Frequency Electron Paramagnetic Resonance Spectroscopy of Nitroxide-Functionalized Nanodiamonds in Aqueous Solution.

PubMed

Akiel, R D; Stepanov, V; Takahashi, S

2017-06-01

Nanodiamond (ND) is an attractive class of nanomaterial for fluorescent labeling, magnetic sensing of biological molecules, and targeted drug delivery. Many of those applications require tethering of target biological molecules on the ND surface. Even though many approaches have been developed to attach macromolecules to the ND surface, it remains challenging to characterize dynamics of tethered molecule. Here, we show high-frequency electron paramagnetic resonance (HF EPR) spectroscopy of nitroxide-functionalized NDs. Nitroxide radical is a commonly used spin label to investigate dynamics of biological molecules. In the investigation, we developed a sample holder to overcome water absorption of HF microwave. Then, we demonstrated HF EPR spectroscopy of nitroxide-functionalized NDs in aqueous solution and showed clear spectral distinction of ND and nitroxide EPR signals. Moreover, through EPR spectral analysis, we investigate dynamics of nitroxide radicals on the ND surface. The demonstration sheds light on the use of HF EPR spectroscopy to investigate biological molecule-functionalized nanoparticles.

Rectangle Surface Coil Array in a Grid Arrangement for Resonance Imaging

DTIC Science & Technology

2016-02-13

switchable array, RF magnetic field, NQR , MRI, NMR, tuning, decoupling I. INTRODUCTION ESONANCE imaging can be accomplished using Nuclear Magnetic...Resonance (NMR) or Nuclear Quadrupole Resonance ( NQR ) techniques. REF [1] and [6] explain the differences between NMR and NQR . What NMR and NQR ...of resonance NQR frequency of 28.1MHz. The matching and tuning is explain in detail in the next section of this paper. Rectangle Surface Coil

Monitoring long-term effects of mild traumatic brain injury with magnetic resonance spectroscopy: a pilot study.

PubMed

Dean, Philip J A; Otaduy, Maria C G; Harris, Lisa M; McNamara, Adam; Seiss, Ellen; Sterr, Annette

2013-08-21

This pilot study explores the metabolic changes associated with persistent postconcussion syndrome (PCS) after mild traumatic brain injury (mTBI; >12 months after injury) using magnetic resonance spectroscopy. We hypothesized that those mTBI participants with PCS will have larger metabolic differences than those without. Data were collected from mTBI participants with PCS, mTBI participants without PCS and non-head-injured participants (all groups: n=8). Magnetic resonance spectroscopy metabolite profiles within the dorsolateral prefrontal cortex showed a reduced creatine/choline ratio in mTBI patients compared with control participants. This data provides initial evidence for residual metabolic changes in chronic mTBI patients, but there was no conclusive relationship between these metabolic changes and PCS symptom report. Creatine is involved in maintaining energy levels in cells with high or fluctuating energy demand, suggesting that there may be some residual energy impairment in chronic mTBI.

Nanoplasmonic Biosensor Using Localized Surface Plasmon Resonance Spectroscopy for Biochemical Detection.

PubMed

Zhang, Diming; Zhang, Qian; Lu, Yanli; Yao, Yao; Li, Shuang; Liu, Qingjun

2017-01-01

Localized surface plasmon resonance (LSPR) associated with metal nanostructures has developed into a highly useful sensor technique. Optical LSPR spectroscopy of nanostructures often shows sharp absorption and scattering peaks, which can be used to probe several bio-molecular interactions. Here, we report nanoplasmonic biosensors using LSPR on nanocup arrays (nanoCA) to recognize bio-molecular binding for biochemical detection. These sensors can be modified to quantify binding of small molecules to proteins for odorant and explosive detections. Electrochemical LSPR biosensors can also be designed by coupling electrochemistry and LSPR spectroscopy measurements. Multiple sensing information can be obtained and electrochemical LSPR property can be investigated for biosensors. In some applications, the electrochemical LSPR biosensor can be used to quantify immunoreactions and enzymatic activity. The biosensors exhibit better performance than those of conventional optical LSPR measurements. With multi-transducers, the nanoplasmonic biosensor can provide a promising approach for bio-detection in environmental monitoring, healthcare diagnostics, and food quality control.

Preparation of a Cobalt(II) Cage: An Undergraduate Laboratory Experiment That Produces a ParaSHIFT Agent for Magnetic Resonance Spectroscopy

ERIC Educational Resources Information Center

Burns, Patrick J.; Tsitovich, Pavel B.; Morrow, Janet R.

2016-01-01

Laboratory experiments that demonstrate the effect of paramagnetic complexes on chemical shifts and relaxation times of protons are a useful way to introduce magnetic resonance spectroscopy (MRS) probes or magnetic resonance imaging (MRI) contrast agents. In this undergraduate inorganic chemistry experiment, a paramagnetic Co(II) cage complex is…

Permanent magnet edge-field quadrupole

DOEpatents

Tatchyn, R.O.

1997-01-21

Planar permanent magnet edge-field quadrupoles for use in particle accelerating machines and in insertion devices designed to generate spontaneous or coherent radiation from moving charged particles are disclosed. The invention comprises four magnetized rectangular pieces of permanent magnet material with substantially similar dimensions arranged into two planar arrays situated to generate a field with a substantially dominant quadrupole component in regions close to the device axis. 10 figs.

Supersonic Quadrupole Noise Theory for High-Speed Helicopter Rotors

NASA Technical Reports Server (NTRS)

Farassat, F.; Brentner, Kenneth S.

1997-01-01

High-speed helicopter rotor impulsive noise prediction is an important problem of aeroacoustics. The deterministic quadrupoles have been shown to contribute significantly to high-speed impulsive (HSI) noise of rotors, particularly when the phenomenon of delocalization occurs. At high rotor-tip speeds, some of the quadrupole sources lie outside the sonic circle and move at supersonic speed. Brentner has given a formulation suitable for efficient prediction of quadrupole noise inside the sonic circle. In this paper, we give a simple formulation based on the acoustic analogy that is valid for both subsonic and supersonic quadrupole noise prediction. Like the formulation of Brentner, the model is exact for an observer in the far field and in the rotor plane and is approximate elsewhere. We give the full analytic derivation of this formulation in the paper. We present the method of implementation on a computer for supersonic quadrupoles using marching cubes for constructing the influence surface (Sigma surface) of an observer space- time variable (x; t). We then present several examples of noise prediction for both subsonic and supersonic quadrupoles. It is shown that in the case of transonic flow over rotor blades, the inclusion of the supersonic quadrupoles improves the prediction of the acoustic pressure signature. We show the equivalence of the new formulation to that of Brentner for subsonic quadrupoles. It is shown that the regions of high quadrupole source strength are primarily produced by the shock surface and the flow over the leading edge of the rotor. The primary role of the supersonic quadrupoles is to increase the width of a strong acoustic signal.

Nuclear Quadrupole Moments and Nuclear Shell Structure

DOE R&D Accomplishments Database

Townes, C. H.; Foley, H. M.; Low, W.

1950-06-23

Describes a simple model, based on nuclear shell considerations, which leads to the proper behavior of known nuclear quadrupole moments, although predictions of the magnitudes of some quadrupole moments are seriously in error.

Highly Dynamic Anion-Quadrupole Networks in Proteins.

PubMed

Kapoor, Karan; Duff, Michael R; Upadhyay, Amit; Bucci, Joel C; Saxton, Arnold M; Hinde, Robert J; Howell, Elizabeth E; Baudry, Jerome

2016-11-01

The dynamics of anion-quadrupole (or anion-π) interactions formed between negatively charged (Asp/Glu) and aromatic (Phe) side chains are for the first time computationally characterized in RmlC (Protein Data Bank entry 1EP0 ), a homodimeric epimerase. Empirical force field-based molecular dynamics simulations predict anion-quadrupole pairs and triplets (anion-anion-π and anion-π-π) are formed by the protein during the simulated trajectory, which suggests that the anion-quadrupole interactions may provide a significant contribution to the overall stability of the protein, with an average of -1.6 kcal/mol per pair. Some anion-π interactions are predicted to form during the trajectory, extending the number of anion-quadrupole interactions beyond those predicted from crystal structure analysis. At the same time, some anion-π pairs observed in the crystal structure exhibit marginal stability. Overall, most anion-π interactions alternate between an "on" state, with significantly stabilizing energies, and an "off" state, with marginal or null stabilizing energies. The way proteins possibly compensate for transient loss of anion-quadrupole interactions is characterized in the RmlC aspartate 84-phenylalanine 112 anion-quadrupole pair observed in the crystal structure. A double-mutant cycle analysis of the thermal stability suggests a possible loss of anion-π interactions compensated by variations of hydration of the residues and formation of compensating electrostatic interactions. These results suggest that near-planar anion-quadrupole pairs can exist, sometimes transiently, which may play a role in maintaining the structural stability and function of the protein, in an otherwise very dynamic interplay of a nonbonded interaction network as well as solvent effects.

Stand-off explosive detection utilizing low power stimulated emission nuclear quadrupole resonance detection and subwavelength focusing wideband super lens

NASA Astrophysics Data System (ADS)

Apostolos, John; Mouyos, William; Feng, Judy; Chase, Walter

2015-05-01

The need for advanced techniques to detect improvised explosive devices (IED) at stand-off distances greater than ten (10) meters has driven AMI Research and Development (AMI) to develop a solution to detect and identify the threat utilizing a forward looking Synthetic Aperture Radar (SAR) combined with our CW radar technology Nuclear Quadrupole Resonance (NQR) detection system. The novel features include a near-field sub-wavelength focusing antenna, a wide band 300 KHz to 300 MHz rapidly scanning CW radar facilitated by a high Q antenna/tuner, and an advanced processor utilizing Rabi transitions where the nucleus oscillates between states under the time dependent incident electromagnetic field and alternately absorbs energy from the incident field while emitting coherent energy via stimulated emission. AMI's Sub-wavelength Focusing Wide Band Super Lens uses a Near-Field SAR, making detection possible at distances greater than ten (10) meters. This super lens is capable of operating on the near-field and focusing electromagnetic waves to resolutions beyond the diffraction limit. When applied to the case of a vehicle approaching an explosive hazard the methodologies of synthetic aperture radar is fused with the array based super resolution and the NQR data processing detecting the explosive hazard.

Sensitivity Analysis and Requirements for Temporally and Spatially Resolved Thermometry Using Neutron Resonance Spectroscopy

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

Fernandez, Juan Carlos; Barnes, Cris William; Mocko, Michael Jeffrey

This report is intended to examine the use of neutron resonance spectroscopy (NRS) to make time- dependent and spatially-resolved temperature measurements of materials in extreme conditions. Specifically, the sensitivities of the temperature estimate on neutron-beam and diagnostic parameters is examined. Based on that examination, requirements are set on a pulsed neutron-source and diagnostics to make a meaningful measurement.

Ultra-High-Field Magnetic Resonance Spectroscopy in Psychiatry.

PubMed

Godlewska, Beata R; Clare, Stuart; Cowen, Philip J; Emir, Uzay E

2017-01-01

The advantages of ultra-high-field (UHF ≥ 7T) MR have been demonstrated in a variety of MR acquisition modalities. Magnetic resonance spectroscopy (MRS) can particularly benefit from substantial gains in signal-to-noise ratio (SNR) and spectral resolution at UHF, enabling the quantification of numerous metabolites, including glutamate, glutamine, glutathione, and γ-aminobutyric acid that are relevant to psychiatric disorders. The aim of this review is to give an overview about the advantages and advances of UHF MRS and its application to psychiatric disorders. In order to provide a practical guide for potential applications of MRS at UHF, a literature review is given, surveying advantages and disadvantages of MRS at UHF. Key concepts, emerging technologies, practical considerations, and applications of UHF MRS are provided. Second, the strength of UHF MRS is demonstrated using some examples of its application in psychiatric disorders.

Ultra-High-Field Magnetic Resonance Spectroscopy in Psychiatry

PubMed Central

Godlewska, Beata R.; Clare, Stuart; Cowen, Philip J.; Emir, Uzay E.

2017-01-01

The advantages of ultra-high-field (UHF ≥ 7T) MR have been demonstrated in a variety of MR acquisition modalities. Magnetic resonance spectroscopy (MRS) can particularly benefit from substantial gains in signal-to-noise ratio (SNR) and spectral resolution at UHF, enabling the quantification of numerous metabolites, including glutamate, glutamine, glutathione, and γ-aminobutyric acid that are relevant to psychiatric disorders. The aim of this review is to give an overview about the advantages and advances of UHF MRS and its application to psychiatric disorders. In order to provide a practical guide for potential applications of MRS at UHF, a literature review is given, surveying advantages and disadvantages of MRS at UHF. Key concepts, emerging technologies, practical considerations, and applications of UHF MRS are provided. Second, the strength of UHF MRS is demonstrated using some examples of its application in psychiatric disorders. PMID:28744229

Ultrasonic Resonance Spectroscopy of Composite Rims for Flywheel Rotors

NASA Technical Reports Server (NTRS)

Harmon, Laura M.; Baaklini, George Y.

2002-01-01

Flywheel energy storage devices comprising multilayered composite rotor systems are being studied extensively for utilization in the International Space Station. These composite material systems were investigated with a recently developed ultrasonic resonance spectroscopy technique. The ultrasonic system employs a continuous swept-sine waveform and performs a fast Fourier transform (FFT) on the frequency response spectrum. In addition, the system is capable of equalizing the amount of energy at each frequency. Equalization of the frequency spectrum, along with interpretation of the second FFT, aids in the evaluation of the fundamental frequency. The frequency responses from multilayered material samples, with and without known defects, were analyzed to assess the capabilities and limitations of this nondestructive evaluation technique for material characterization and defect detection. Amplitude and frequency changes were studied from ultrasonic responses of thick composite rings and a multiring composite rim. A composite ring varying in thickness was evaluated to investigate the full thickness resonance. The frequency response characteristics from naturally occurring voids in a composite ring were investigated. Ultrasonic responses were compared from regions with and without machined voids in a composite ring and a multiring composite rim. Finally, ultrasonic responses from the multiring composite rim were compared before and after proof spin testing to 63,000 rpm.

Matter-wave solitons supported by quadrupole-quadrupole interactions and anisotropic discrete lattices

NASA Astrophysics Data System (ADS)

Zhong, Rong-Xuan; Huang, Nan; Li, Huang-Wu; He, He-Xiang; Lü, Jian-Tao; Huang, Chun-Qing; Chen, Zhao-Pin

2018-04-01

We numerically and analytically investigate the formations and features of two-dimensional discrete Bose-Einstein condensate solitons, which are constructed by quadrupole-quadrupole interactional particles trapped in the tunable anisotropic discrete optical lattices. The square optical lattices in the model can be formed by two pairs of interfering plane waves with different intensities. Two hopping rates of the particles in the orthogonal directions are different, which gives rise to a linear anisotropic system. We find that if all of the pairs of dipole and anti-dipole are perpendicular to the lattice panel and the line connecting the dipole and anti-dipole which compose the quadrupole is parallel to horizontal direction, both the linear anisotropy and the nonlocal nonlinear one can strongly influence the formations of the solitons. There exist three patterns of stable solitons, namely horizontal elongation quasi-one-dimensional discrete solitons, disk-shape isotropic pattern solitons and vertical elongation quasi-continuous solitons. We systematically demonstrate the relationships of chemical potential, size and shape of the soliton with its total norm and vertical hopping rate and analytically reveal the linear dispersion relation for quasi-one-dimensional discrete solitons.

Cerebral metabolic abnormalities in congestive heart failure detected by proton magnetic resonance spectroscopy.

PubMed

Lee, C W; Lee, J H; Kim, J J; Park, S W; Hong, M K; Kim, S T; Lim, T H; Park, S J

1999-04-01

Using proton magnetic resonance spectroscopy, we investigated cerebral metabolism and its determinants in congestive heart failure (CHF), and the effects of cardiac transplantation on these measurements. Few data are available about cerebral metabolism in CHF. Fifty patients with CHF (ejection fraction < or = 35%) and 20 healthy volunteers were included for this study. Of the patients, 10 patients underwent heart transplantation. All subjects performed symptom-limited bicycle exercise test. Proton magnetic resonance spectroscopy (1H MRS) was obtained from localized regions (8 to 10 ml) of occipital gray matter (OGM) and parietal white matter (PWM). Absolute levels of the metabolites (N-acetylaspartate, creatine, choline, myo-inositol) were calculated. In PWM only creatine level was significantly lower in CHF than in control subjects, but in OGM all four metabolite levels were decreased in CHF. The creatine level was independently correlated with half-recovery time and duration of heart failure symptoms in PWM (r = -0.56, p < 0.05), and with peak oxygen consumption and serum sodium concentration in OGM (r = 0.58, p < 0.05). Cerebral metabolic abnormalities were improved after successful cardiac transplantation. This study shows that cerebral metabolism is abnormally deranged in advanced CHF and it may serve as a potential marker of the disease severity.

Sphericity determination using resonant ultrasound spectroscopy

DOEpatents

Dixon, Raymond D.; Migliori, Albert; Visscher, William M.

1994-01-01

A method is provided for grading production quantities of spherical objects, such as roller balls for bearings. A resonant ultrasound spectrum (RUS) is generated for each spherical object and a set of degenerate sphere-resonance frequencies is identified. From the degenerate sphere-resonance frequencies and known relationships between degenerate sphere-resonance frequencies and Poisson's ratio, a Poisson's ratio can be determined, along with a "best" spherical diameter, to form spherical parameters for the sphere. From the RUS, fine-structure resonant frequency spectra are identified for each degenerate sphere-resonance frequency previously selected. From each fine-structure spectrum and associated sphere parameter values an asphericity value is determined. The asphericity value can then be compared with predetermined values to provide a measure for accepting or rejecting the sphere.

Borman effect in resonant diffraction of X-rays

NASA Astrophysics Data System (ADS)

Oreshko, A. P.

2013-08-01

A dynamic theory of resonant diffraction (occurring when the energy of incident radiation is close to the energy of the absorption edge of an element in the composition of a given substance) of synchronous X-rays is developed in the two-wave approximation in the coplanar Laue geometry for large grazing angles in perfect crystals. A sharp decrease in the absorption coefficient in the substance with simultaneously satisfied diffraction conditions (Borman effect) is demonstrated, and the theoretical and first experimental results are compared. The calculations reveal the possibility of applying this approach in analyzing the quadrupole-quadrupole contribution to the absorption coefficient.

Noise reduction in negative-ion quadrupole mass spectrometry

DOEpatents

Chastagner, P.

1993-04-20

A quadrupole mass spectrometer (QMS) system is described having an ion source, quadrupole mass filter, and ion collector/recorder system. A weak, transverse magnetic field and an electron collector are disposed between the quadrupole and ion collector. When operated in negative ion mode, the ion source produces a beam of primarily negatively-charged particles from a sample, including electrons as well as ions. The beam passes through the quadrupole and enters the magnetic field, where the electrons are deflected away from the beam path to the electron collector. The negative ions pass undeflected to the ion collector where they are detected and recorded as a mass spectrum.

Noise reduction in negative-ion quadrupole mass spectrometry

DOEpatents

Chastagner, Philippe

1993-01-01

A quadrupole mass spectrometer (QMS) system having an ion source, quadrupole mass filter, and ion collector/recorder system. A weak, transverse magnetic field and an electron collector are disposed between the quadrupole and ion collector. When operated in negative ion mode, the ion source produces a beam of primarily negatively-charged particles from a sample, including electrons as well as ions. The beam passes through the quadrupole and enters the magnetic field, where the electrons are deflected away from the beam path to the electron collector. The negative ions pass undeflected to the ion collector where they are detected and recorded as a mass spectrum.

Sphericity determination using resonant ultrasound spectroscopy

DOEpatents

Dixon, R.D.; Migliori, A.; Visscher, W.M.

1994-10-18

A method is provided for grading production quantities of spherical objects, such as roller balls for bearings. A resonant ultrasound spectrum (RUS) is generated for each spherical object and a set of degenerate sphere-resonance frequencies is identified. From the degenerate sphere-resonance frequencies and known relationships between degenerate sphere-resonance frequencies and Poisson's ratio, a Poisson's ratio can be determined, along with a 'best' spherical diameter, to form spherical parameters for the sphere. From the RUS, fine-structure resonant frequency spectra are identified for each degenerate sphere-resonance frequency previously selected. From each fine-structure spectrum and associated sphere parameter values an asphericity value is determined. The asphericity value can then be compared with predetermined values to provide a measure for accepting or rejecting the sphere. 14 figs.

Nonuniform radiation damage in permanent magnet quadrupoles.

PubMed

Danly, C R; Merrill, F E; Barlow, D; Mariam, F G

2014-08-01

We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL's pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components.

Ab initio correlated calculations of rare-gas dimer quadrupoles

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

Donchev, Alexander G.

2007-10-15

This paper reports ab initio calculations of rare gas (RG=Kr, Ar, Ne, and He) dimer quadrupoles at the second order of Moeller-Plesset perturbation theory (MP2). The study reveals the crucial role of the dispersion contribution to the RG{sub 2} quadrupole in the neighborhood of the equilibrium dimer separation. The magnitude of the dispersion quadrupole is found to be much larger than that predicted by the approximate model of Hunt. As a result, the total MP2 quadrupole moment is significantly smaller than was assumed in virtually all previous related studies. An analytical model for the distance dependence of the RG{sub 2}more » quadrupole is proposed. The model is based on the effective-electron approach of Jansen, but replaces the original Gaussian approximation to the electron density in an RG atom by an exponential one. The role of the nonadditive contribution in RG{sub 3} quadrupoles is discussed.« less

Induced CMB quadrupole from pointing offsets

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

Moss, Adam; Scott, Douglas; Sigurdson, Kris, E-mail: adammoss@phas.ubc.ca, E-mail: dscott@phas.ubc.ca, E-mail: krs@phas.ubc.ca

2011-01-01

Recent claims in the literature have suggested that the WMAP quadrupole is not primordial in origin, and arises from an aliasing of the much larger dipole field because of incorrect satellite pointing. We attempt to reproduce this result and delineate the key physics leading to the effect. We find that, even if real, the induced quadrupole would be smaller than the WMAP value. We discuss reasons why the WMAP data are unlikely to suffer from this particular systematic effect, including the implications for observations of point sources. Given this evidence against the reality of the effect, the similarity between themore » pointing-offset-induced signal and the actual quadrupole then appears to be quite puzzling. However, we find that the effect arises from a convolution between the gradient of the dipole field and anisotropic coverage of the scan direction at each pixel. There is something of a directional conspiracy here — the dipole signal lies close to the Ecliptic Plane, and its direction, together with the WMAP scan strategy, results in a strong coupling to the Y{sub 2,−1} component in Ecliptic co-ordinates. The dominant strength of this component in the measured quadrupole suggests that one should exercise increased caution in interpreting its estimated amplitude. The Planck satellite has a different scan strategy which does not so directly couple the dipole and quadrupole in this way and will soon provide an independent measurement.« less

Laser-ultrasound spectroscopy apparatus and method with detection of shear resonances for measuring anisotropy, thickness, and other properties

DOEpatents

Levesque, Daniel; Moreau, Andre; Dubois, Marc; Monchalin, Jean-Pierre; Bussiere, Jean; Lord, Martin; Padioleau, Christian

2000-01-01

Apparatus and method for detecting shear resonances includes structure and steps for applying a radiation pulse from a pulsed source of radiation to an object to generate elastic waves therein, optically detecting the elastic waves generated in the object, and analyzing the elastic waves optically detected in the object. These shear resonances, alone or in combination with other information, may be used in the present invention to improve thickness measurement accuracy and to determine geometrical, microstructural, and physical properties of the object. At least one shear resonance in the object is detected with the elastic waves optically detected in the object. Preferably, laser-ultrasound spectroscopy is utilized to detect the shear resonances.

Correlating brain blood oxygenation level dependent (BOLD) fractal dimension mapping with magnetic resonance spectroscopy (MRS) in Alzheimer's disease.

PubMed

Warsi, Mohammed A; Molloy, William; Noseworthy, Michael D

2012-10-01

To correlate temporal fractal structure of resting state blood oxygen level dependent (rsBOLD) functional magnetic resonance imaging (fMRI) with in vivo proton magnetic resonance spectroscopy ((1)H-MRS), in Alzheimer's disease (AD) and healthy age-matched normal controls (NC). High temporal resolution (4 Hz) rsBOLD signal and single voxel (left putamen) magnetic resonance spectroscopy data was acquired in 33 AD patients and 13 NC. The rsBOLD data was analyzed using two types of fractal dimension (FD) analysis based on relative dispersion and frequency power spectrum. Comparisons in FD were performed between AD and NC, and FD measures were correlated with (1)H-MRS findings. Temporal fractal analysis of rsBOLD, was able to differentiate AD from NC subjects (P = 0.03). Low FD correlated with markers of AD severity including decreased concentrations of N-acetyl aspartate (R = 0.44, P = 0.015) and increased myoinositol (mI) (R = -0.45, P = 0.012). Based on these results we suggest fractal analysis of rsBOLD could provide an early marker of AD.

Investigation of Fat Metabolism during Antiobesity Interventions by Magnetic Resonance Imaging and Spectroscopy.

PubMed

Pola, Arunima; Sadananthan, Suresh Anand; Gopalan, Venkatesh; Tan, Min-Li Sandra; Keong, Terry Yew; Zhou, Zhihong; Ishino, Seigo; Nakano, Yoshihide; Watanabe, Masanori; Horiguchi, Takashi; Nishimoto, Tomoyuki; Zhu, Bin; Velan, S Sendhil

2014-01-01

The focus of current treatments for obesity is to reduce the body weight or visceral fat, which requires longer duration to show effect. In this study, we investigated the short-term changes in fat metabolism in liver, abdomen, and skeletal muscle during antiobesity interventions including Sibutra mine treatment and diet restriction in obese rats using magnetic resonance imaging, magnetic resonance spectroscopy, and blood chemistry. Sibutramine is an antiobesity drug that results in weight loss by increasing satiety and energy expenditure. The Sibutramine-treated rats showed reduction of liver fat and intramyocellular lipids on day 3. The triglycerides (TG) decreased on day 1 and 3 compared to baseline (day 0). The early response/nonresponse in different fat depots will permit optimization of treatment for better clinical outcome rather than staying with a drug for longer periods.

Phosphorous magnetic resonance spectroscopy-based skeletal muscle bioenergetic studies in subclinical hypothyroidism.

PubMed

Rana, P; Sripathy, G; Varshney, A; Kumar, P; Devi, M Memita; Marwaha, R K; Tripathi, R P; Khushu, S

2012-02-01

Subclinical hypothyroidism (sHT) is considered to be a milder form of thyroid dysfunction. Few earlier studies have reported neuromuscular symptoms as well as impaired muscle metabolism in sHT patients. In this study we report our findings on muscle bioenergetics in sHT patients using phosphorous magnetic resonance spectroscopy (31P MRS) and look upon the possibility to use 31P MRS technique as a clinical marker for monitoring muscle function in subclinical thyroid dysfunction. Seventeen normal subjects, 15 patients with sHT, and 9 patients with hypothyroidism performed plantar flexion exercise while lying supine in 1.5 T magnetic resonance scanner using custom built exercise device. MR Spectroscopy measurements of inorganic phosphate (Pi), phosphocreatine (PCr), and ATP of the calf muscle were taken during rest, at the end of exercise and in the recovery phase. PCr recovery rate constant (kPCr) and oxidative capacity were calculated by monoexponential fit of PCr vs time (t) at the beginning of recovery. We observed that changes in some of the phosphometabolites (increased phosphodiester levels and Pi concentration) in sHT patients which were similar to those detected in patients with hypothyroidism. However, our results do not demonstrate impaired muscle oxidative metabolism in sHT patients based upon PCr dynamics as observed in hypothyroid patients. 31P MRS-based PCr recovery rate could be used as a marker for monitoring muscle oxidative metabolism in sub clinical thyroid dysfunction.

Resonant Absorption in GaAs-Based Nanowires by Means of Photo-Acoustic Spectroscopy

NASA Astrophysics Data System (ADS)

Petronijevic, E.; Leahu, G.; Belardini, A.; Centini, M.; Li Voti, R.; Hakkarainen, T.; Koivusalo, E.; Guina, M.; Sibilia, C.

2018-03-01

Semiconductor nanowires made of high refractive index materials can couple the incoming light to specific waveguide modes that offer resonant absorption enhancement under the bandgap wavelength, essential for light harvesting, lasing and detection applications. Moreover, the non-trivial ellipticity of such modes can offer near field interactions with chiral molecules, governed by near chiral field. These modes are therefore very important to detect. Here, we present the photo-acoustic spectroscopy as a low-cost, reliable, sensitive and scattering-free tool to measure the spectral position and absorption efficiency of these modes. The investigated samples are hexagonal nanowires with GaAs core; the fabrication by means of lithography-free molecular beam epitaxy provides controllable and uniform dimensions that allow for the excitation of the fundamental resonant mode around 800 nm. We show that the modulation frequency increase leads to the discrimination of the resonant mode absorption from the overall absorption of the substrate. As the experimental data are in great agreement with numerical simulations, the design can be optimized and followed by photo-acoustic characterization for a specific application.

Metal Ion Interactions with Immunoglobulin G (IgG). 1. Preliminary Studies with Electron Paramagnetic Resonance (EPR) Spectroscopy and Ultrafiltration

DTIC Science & Technology

1978-12-12

EPR and ultrafiltration studies are recommceided to conduct luture metal ion- IgG binding research. Using Scatchard plots, bind.ng levels can be...of the binding sites can be best pursued by EPR and ultrafiltration using the fragments of IgG . This report noted some difference in the binding...immunoelectrophoresis, ultrafiltration, UV spectroscopy, atomic absorption spectroscopy, and electron paramagnetic resonance (EPR). IgG used ,- ,is non

Theory of electronic structures and nuclear quadrupole interactions in molecular solids and semiconductor surfaces

NASA Astrophysics Data System (ADS)

Pati, Ranjit

We have investigated, using the Hartree-Fock Roothaan variational procedure, the electronic structures and associated nuclear quadrupole interactions (NQI) for the molecular solids, RDX (C3H6N6O6),/ /beta- HMX(C4H8N8O8), Cocaine (C17H21NO4), Cocaine Hydrochloride (C17H21NO4HCl) and Heroin (C21H23NO5) and for the (111) surface of silicon with adsorbed radioactive 111In atom and negative cadmium ion containing the excited nucleus 111Cd/* resulting from electron capture by lllIn. Our investigations indicate that for the ring 14N NQI parameters in RDX and β-HMX there is very good agreement between theory and experiment. For the peripheral 14N nuclei in NO2 groups, while the calculated electronic structures do explain the much weaker quadrupole coupling constants for these nuclei relative to the ring 14N nuclei, there are significant differences between theory and experiment. The influence of intermolecular interactions between adjacent molecules in the solid is invoked as a possible source for these differences. For the controlled substances, Cocaine and Heroin, again very good agreement is obtained between theory and experiment. For Cocaine Hydrochloride theory is able to explain the much smaller observed 14N nuclear quadrupole resonance frequency as compared to pure Cocaine. However there are significant differences between theory and experiment for the 14N and 35Cl quadrupole resonance frequencies. The influence of intermolecular interactions is one of the factors suggested to explain the difference. For the silicon (111) surface, the observed 111Cd/* NQI parameters, with the cadmium nucleus assumed to be located at the same site as the 111In nucleus from which it is generated, can be successfully explained by theory with the indium atom located at the two distinct sites available with the DAS model for the 7 x 7 reconstructed (111) surface. Some quantitative differences still remain, one of the main factor suggested for their explanation being a need for a

Application of acoustic micro-resonators in quartz-enhanced photoacoustic spectroscopy for trace gas analysis

NASA Astrophysics Data System (ADS)

Zheng, Huadan; Dong, Lei; Wu, Hongpeng; Yin, Xukun; Xiao, Liantuan; Jia, Suotang; Curl, Robert F.; Tittel, Frank K.

2018-01-01

During the past 15 years since the first report of quartz enhanced photoacoustic spectroscopy (QEPAS), QEPAS has become one of the leading optical techniques for trace chemical gas sensing. This paper is a review of the current state-of-the art of QEPAS. QEPAS based spectrophones with different acoustic micro-resonators (AmR) configurations employing both standard quartz tuning forks (QTFs) and custom-made QTFs are summarized and discussed in detail.

A study of spin isovector giant resonances with the208Pb(n, p)208Tl reaction

NASA Astrophysics Data System (ADS)

Moinester, M. A.; Trudel, A.; Raywood, K.; Yen, S.; Spicer, B. M.; Abegg, R.; Alford, W. P.; Auerbach, N.; Celler, A.; Frekers, D.; Häusser, O.; Helmer, R. L.; Henderson, R.; Hicks, K. H.; Jackson, K. P.; Jeppesen, R. G.; King, N. S. P.; Long, S.; Miller, C. A.; Vetterli, M.; Watson, J.; Yavin, A. I.

1989-10-01

The208Pb(n, p)208Tl reaction was studied at 198 and 458 MeV in a search for isovector spin giant resonances. Peaks at 5.1 MeV and 13.6 MeV excitation in208Tl are observed and discussed as candidates for the T> spin giant dipole resonance (SGDR), the spin isovector monopole resonance (SIVM), and the spin isovector quadrupole resonance (SIVQ).

79/81Br nuclear quadrupole resonance spectroscopic characterization of halogen bonds in supramolecular assemblies† †Electronic supplementary information (ESI) available: 13C SSNMR spectra, powder X-ray diffractograms. See DOI: 10.1039/c8sc01094c

PubMed Central

Cerreia Vioglio, P.; Szell, P. M. J.; Chierotti, M. R.; Gobetto, R.

2018-01-01

Despite the applicability of solid-state NMR to study the halogen bond, the direct NMR detection of 79/81Br covalently bonded to carbon remains impractical due to extremely large spectral widths, even at ultra-high magnetic fields. In contrast, nuclear quadrupole resonance (NQR) offers comparatively sharp resonances. Here, we demonstrate the abilities of 79/81Br NQR to characterize the electronic changes in the C–Br···N halogen bonding motifs found in supramolecular assemblies constructed from 1,4-dibromotetrafluorobenzene and nitrogen-containing heterocycles. An increase in the bromine quadrupolar coupling constant is observed, which correlates linearly with the halogen bond distance (dBr···N). Notably, 79/81Br NQR is able to distinguish between two symmetry-independent halogen bonds in the same crystal structure. This approach offers a rapid and reliable indication for the occurrence of a halogen bond, with experimental times limited only by the observation of 79/81Br NQR resonances. PMID:29899948

Carbon-deuterium rotational-echo double-resonance NMR spectroscopy of lyophilized aspartame formulations.

PubMed

Luthra, Suman A; Utz, Marcel; Gorman, Eric M; Pikal, Michael J; Munson, Eric J; Lubach, Joseph W

2012-01-01

In this study, changes in the local conformation of aspartame were observed in annealed lyophilized glasses by monitoring changes in the distance between two labeled sites using C-(2)H rotational-echo double-resonance (REDOR) nuclear magnetic resonance (NMR) spectroscopy. Confirmation that the REDOR experiments were producing accurate distance measurement was ensured by measuring the (13)C-(15)N distance in glycine. The experiment was further verified by measuring the REDOR dephasing curve on (13)C-(2)H methionine. (13)C-(2)H REDOR dephasing curves were then measured on lyophilized aspartame-disaccharide formulations. In aspartame-sucrose formulation, the internuclear distances increased upon annealing, which correlated with decreased chemical reactivity. By contrast, annealing had only a minimal effect on the dephasing curve in aspartame-trehalose formulation. The results show that stability is a function of both mobility and local structure (conformation), even in a small molecule system such as lyophilized aspartame-sucrose. Copyright © 2011 Wiley-Liss, Inc.

Resonant Ultrasound Spectroscopy studies of Berea sandstone at high temperature

DOE PAGES

Davis, Eric S.; Sturtevant, Blake T.; Sinha, Dipen N.; ...

2016-09-04

Resonant Ultrasound Spectroscopy was used in this paper to determine the elastic moduli of Berea sandstone from room temperature to 478 K. Sandstone is a common component of oil reservoirs, and the temperature range was chosen to be representative of typical downhole conditions, down to about 8 km. In agreement with previous works, Berea sandstone was found to be relatively soft with a bulk modulus of approximately 6 GPa as compared to 37.5 GPa for α-quartz at room temperature and pressure. Finally, it was found that Berea sandstone undergoes a ~17% softening in bulk modulus between room temperature and 385more » K, followed by an abnormal behavior of similar stiffening between 385 K and 478 K.« less

Resonant Ultrasound Spectroscopy studies of Berea sandstone at high temperature

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

Davis, Eric S.; Sturtevant, Blake T.; Sinha, Dipen N.

Resonant Ultrasound Spectroscopy was used in this paper to determine the elastic moduli of Berea sandstone from room temperature to 478 K. Sandstone is a common component of oil reservoirs, and the temperature range was chosen to be representative of typical downhole conditions, down to about 8 km. In agreement with previous works, Berea sandstone was found to be relatively soft with a bulk modulus of approximately 6 GPa as compared to 37.5 GPa for α-quartz at room temperature and pressure. Finally, it was found that Berea sandstone undergoes a ~17% softening in bulk modulus between room temperature and 385more » K, followed by an abnormal behavior of similar stiffening between 385 K and 478 K.« less

Sensing a heart infarction marker with surface plasmon resonance spectroscopy

NASA Astrophysics Data System (ADS)

Kunz, Ulrich; Katerkamp, Andreas; Renneberg, Reinhard; Spener, Friedrich; Cammann, Karl

1995-02-01

In this study a direct immunosensor for heart-type fatty acid binding protein (FABP) based on surface plasmon resonance spectroscopy (SPRS) is presented. FABP can be used as a heart infarction marker in clinical diagnostics. The development of a simple and cheap direct optical sensor device is reported in this paper as well as immobilization procedures and optimization of the measuring conditions. The correct working of the SPRS device is controlled by comparing the signals with theoretical calculated values. Two different immunoassay techniques were optimized for a sensitive FABP-analysis. The competitive immunoassay was superior to the sandwich configuration as it had a lower detection limit (100 ng/ml), needed less antibodies and could be carried out in one step.

Quantum interference in laser spectroscopy of highly charged lithiumlike ions

NASA Astrophysics Data System (ADS)

Amaro, Pedro; Loureiro, Ulisses; Safari, Laleh; Fratini, Filippo; Indelicato, Paul; Stöhlker, Thomas; Santos, José Paulo

2018-02-01

We investigate the quantum interference induced shifts between energetically close states in highly charged ions, with the energy structure being observed by laser spectroscopy. In this work, we focus on hyperfine states of lithiumlike heavy-Z isotopes and quantify how much quantum interference changes the observed transition frequencies. The process of photon excitation and subsequent photon decay for the transition 2 s →2 p →2 s is implemented with fully relativistic and full-multipole frameworks, which are relevant for such relativistic atomic systems. We consider the isotopes 79+207Pb and 80+209Bi due to experimental interest, as well as other examples of isotopes with lower Z , namely 56+141Pr and 64+165Ho. We conclude that quantum interference can induce shifts up to 11% of the linewidth in the measurable resonances of the considered isotopes, if interference between resonances is neglected. The inclusion of relativity decreases the cross section by 35%, mainly due to the complete retardation form of the electric dipole multipole. However, the contribution of the next higher multipoles (e.g., magnetic quadrupole) to the cross section is negligible. This makes the contribution of relativity and higher-order multipoles to the quantum interference induced shifts a minor effect, even for heavy-Z elements.

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

PubMed

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

2012-01-01

This report describes our efforts on quantification of tissue metabolite concentrations in mM by nuclear Overhauser enhanced and proton decoupled (13) C magnetic resonance spectroscopy and the Electric Reference To access In vivo Concentrations (ERETIC) method. Previous work showed that a calibrated synthetic magnetic resonance spectroscopy-like signal transmitted through an optical fiber and inductively coupled into a transmit/receive coil represents a reliable reference standard for in vivo (1) H magnetic resonance spectroscopy quantification on a clinical platform. In this work, we introduce a related implementation that enables simultaneous proton decoupling and ERETIC-based metabolite quantification and hence extends the applicability of the ERETIC method to nuclear Overhauser enhanced and proton decoupled in vivo (13) C magnetic resonance spectroscopy. In addition, ERETIC signal stability under the influence of simultaneous proton decoupling is investigated. The proposed quantification method was cross-validated against internal and external reference standards on human skeletal muscle. The ERETIC signal intensity stability was 100.65 ± 4.18% over 3 months including measurements with and without proton decoupling. Glycogen and unsaturated fatty acid concentrations measured with the ERETIC method were in excellent agreement with internal creatine and external phantom reference methods, showing a difference of 1.85 ± 1.21% for glycogen and 1.84 ± 1.00% for unsaturated fatty acid between ERETIC and creatine-based quantification, whereas the deviations between external reference and creatine-based quantification are 6.95 ± 9.52% and 3.19 ± 2.60%, respectively. Copyright © 2011 Wiley Periodicals, Inc.

Momentum-resolved radio-frequency spectroscopy of a spin-orbit-coupled atomic Fermi gas near a Feshbach resonance in harmonic traps

NASA Astrophysics Data System (ADS)

Peng, Shi-Guo; Liu, Xia-Ji; Hu, Hui; Jiang, Kaijun

2012-12-01

We theoretically investigate the momentum-resolved radio-frequency spectroscopy of a harmonically trapped atomic Fermi gas near a Feshbach resonance in the presence of equal Rashba and Dresselhaus spin-orbit coupling. The system is qualitatively modeled as an ideal gas mixture of atoms and molecules, in which the properties of molecules, such as the wave function, binding energy, and effective mass, are determined from the two-particle solution of two interacting atoms. We calculate separately the radio-frequency response from atoms and molecules at finite temperatures by using the standard Fermi golden rule and take into account the effect of harmonic traps within local density approximation. The total radio-frequency spectroscopy is discussed as functions of temperature and spin-orbit coupling strength. Our results give a qualitative picture of radio-frequency spectroscopy of a resonantly interacting spin-orbit-coupled Fermi gas and can be directly tested in atomic Fermi gases of 40K atoms at Shanxi University and 6Li atoms at the Massachusetts Institute of Technology.

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

PubMed

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

2013-04-01

When fermenting milk, lactic bacteria convert part of α- and β-lactoses into d- and l- lactic acids, causing a pH decrease responsible for casein coagulation. Lactic acid monitoring during fermentation is essential for the control of dairy gel textural and organoleptic properties, and is a way to evaluate strain efficiency. Currently, titrations are used to follow the quantity of acids formed during jellification of milk but they are not specific to lactic acid. An analytical method without the use of any reagent was investigated to quantify lactic acid during milk fermentation: in situ quantitative proton nuclear magnetic resonance spectroscopy. Two methods using in situ quantitative proton nuclear magnetic resonance spectroscopy were compared: (1) d- and l-lactic acids content determination, using the resonance of their methyl protons, showing an increase from 2.06 ± 0.02 to 8.16 ± 0.74 g/L during 240 min of fermentation; and (2) the determination of the α- and β-lactoses content, decreasing from 42.68 ± 0.02 to 30.76 ± 1.75 g/L for the same fermentation duration. The ratio between the molar concentrations of produced lactic acids and consumed lactoses enabled cross-validation, as the value (2.02 ± 0.18) is consistent with lactic acid bacteria metabolism. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Optimally designed narrowband guided-mode resonance reflectance filters for mid-infrared spectroscopy

PubMed Central

Liu, Jui-Nung; Schulmerich, Matthew V.; Bhargava, Rohit; Cunningham, Brian T.

2011-01-01

An alternative to the well-established Fourier transform infrared (FT-IR) spectrometry, termed discrete frequency infrared (DFIR) spectrometry, has recently been proposed. This approach uses narrowband mid-infrared reflectance filters based on guided-mode resonance (GMR) in waveguide gratings, but filters designed and fabricated have not attained the spectral selectivity (≤ 32 cm−1) commonly employed for measurements of condensed matter using FT-IR spectroscopy. With the incorporation of dispersion and optical absorption of materials, we present here optimal design of double-layer surface-relief silicon nitride-based GMR filters in the mid-IR for various narrow bandwidths below 32 cm−1. Both shift of the filter resonance wavelengths arising from the dispersion effect and reduction of peak reflection efficiency and electric field enhancement due to the absorption effect show that the optical characteristics of materials must be taken into consideration rigorously for accurate design of narrowband GMR filters. By incorporating considerations for background reflections, the optimally designed GMR filters can have bandwidth narrower than the designed filter by the antireflection equivalence method based on the same index modulation magnitude, without sacrificing low sideband reflections near resonance. The reported work will enable use of GMR filters-based instrumentation for common measurements of condensed matter, including tissues and polymer samples. PMID:22109445

A Magnetic Resonance Spectroscopy Study of the Anterior Cingulate Cortex In Youth with Emotional Dysregulation

PubMed Central

Wozniak, Janet; Gönenç, Atilla; Biederman, Joseph; Moore, Constance; Joshi, Gagan; Georgiopoulos, Anna; Hammerness, Paul; McKillop, Hannah; Lukas, Scot E.; Henin, Aude

2017-01-01

Background The main aim of this study was to use proton Magnetic Resonance Spectroscopy (MRS) to identify brain biomarkers for emotional dysregulation in youth as measured by subscales of the Child Behavior Checklist (CBCL). Methods We measured glutamate (Glu) concentrations in the anterior cingulated cortex (ACC) of 37 pediatric subjects (aged 6-17 years) using high field (4.0 Tesla) proton Magnetic Resonance Spectroscopy (MRS). Subjects were grouped based on combined T scores on three subscales (Anxiety/Depression, Aggression and Attention) of the CBCL previously associated with deficits in the regulation of emotion. Subjects were stratified into those with high (>180) (N=10) and low (<180) (N=27) scores. Limitations Limitations include small sample size, wide age range studied, focus on Anterior Cingulate Cortex (ACC) only, and that some subjects received psychopharmacological treatments. Results We found a statistically significant correlation between Glu levels in the ACC and CBCL dysregulation profile scores among subjects with high dysregulation profile scores. Conclusions These results suggest that glutamatergic dysregulation in the ACC may represent a useful biomarker of emotional dysregulation in youth. Further investigation into the causality, time line and utility as a predictive metric is warranted. PMID:22652930

Rapid detection of metastatic melanoma in lymph nodes using proton magnetic resonance spectroscopy of fine needle aspiration biopsy specimens.

PubMed

Lean, Cynthia L; Bourne, Roger; Thompson, John F; Scolyer, Richard A; Stretch, Jonathan; Li, Ling-Xi Lawrence; Russell, Peter; Mountford, Carolyn

2003-06-01

Accurate staging of patients with primary cutaneous melanoma includes assessment of regional lymph nodes for the presence of micrometastatic disease. Sentinel lymph node biopsy is highly accurate but is an invasive surgical procedure with a 5-10% complication rate, and requires labour-intensive and expensive histological examination to identify disease. A rapid, accurate and cost-effective non-surgical technique able to detect micrometastatic deposits of melanoma in regional lymph nodes would be of great benefit. Fine needle aspiration biopsies and tissue specimens were obtained from lymph nodes from 18 patients undergoing node resection for metastatic melanoma and five patients undergoing radical retropubic prostatectomy. One-dimensional proton magnetic resonance spectroscopy was undertaken at 360 MHz (8.5 T). Lymph nodes were cut into 3 mm thick slices and embedded. Four sequential 5 microm tissue sections were cut from each block and stained, with haematoxylin and eosin, for S100 protein, for HMB45, and again with haematoxylin and eosin, respectively. Proton magnetic resonance spectroscopy distinguished between benign and malignant lymph node tissue (P < 0.001, separate t-test) and benign and malignant lymph node fine needle aspiration biopsy (P < 0.012) based on the ratio of the integrals of resonances from lipid/other metabolites (1.8-2.5 p.p.m. region) and 'choline' (3.1-3.3 p.p.m. region). In conclusion, one-dimensional proton magnetic resonance spectroscopy on a simple fine needle aspiration biopsy can distinguish lymph nodes containing metastatic melanoma from uninvolved nodes, providing a rapid, accurate and cost-effective non-surgical technique to assess regional lymph nodes in patients with melanoma.

Multipolar second-harmonic generation by Mie-resonant dielectric nanoparticles

NASA Astrophysics Data System (ADS)

Smirnova, Daria; Smirnov, Alexander I.; Kivshar, Yuri S.

2018-01-01

By combining analytical and numerical approaches, we study resonantly enhanced second-harmonic generation by individual high-index dielectric nanoparticles made of centrosymmetric materials. Considering both bulk and surface nonlinearities, we describe second-harmonic nonlinear scattering from a silicon nanoparticle optically excited in the vicinity of the magnetic and electric dipolar resonances. We discuss the contributions of different nonlinear sources and the effect of the low-order optical Mie modes on the characteristics of the generated far field. We demonstrate that the multipolar expansion of the radiated field is dominated by dipolar and quadrupolar modes (two axially symmetric electric quadrupoles, an electric dipole, and a magnetic quadrupole) and the interference of these modes can ensure directivity of the nonlinear scattering. The developed multipolar analysis can be instructive for interpreting the far-field measurements of the nonlinear scattering and it provides prospective insights into a design of complementary metal-oxide-semiconductor compatible nonlinear nanoantennas fully integrated with silicon-based photonic circuits, as well as methods of nonlinear diagnostics.

High-resolution molecular-beam spectroscopy of NaCN and Na 13CN

NASA Astrophysics Data System (ADS)

van Vaals, J. J.; Meerts, W. Leo; Dymanus, A.

The sodium cyanide molecule was studied by molecular-beam electric-resonance spectroscopy in the microwave region. We used the seeded-beam technique to produce a supersonic beam with strong translational, rotational and vibrational cooling. In the frequency range 9.5-40 GHz we observed and identified for NaCN 186 and for Na 13CN 107 hyperfine transitions in 20 and 16 rotational transitions, respectively, all in the ground vibrational state. The rotational, the five quartic and three sextic centrifugal distortion constants of NaCN are: A″ = 57921.954(7) MHz; B″ = 8369.312(2) MHz, C″ = 7272.712(2) MHz. All quadrupole and several spin-rotation coupling constants for the hyperfine interaction were evaluated. The quadrupole coupling constants (in MHz) for NaCN are: eQq12(Na) = -5.344(5), eQq12 = 2.397(7). eQq12(N) = 2.148(4), eQq12(N) = -4.142(5). From these constants and those of Na 13CN we have determined the principal components of the quadrupole coupling tensor for potassium and nitrogen. The structure of sodium cyanide evaluated from the rotational constants of NaCN and Na 13CN was found to be T shaped, similar to the structure of KCN but completely different from the linear isocyanide configuration of LiNC. The effective structural parameters for sodium cyanide in the ground vibrational state are: rCN = 1.170(4) Å, rNaC = 2.379(15) Å, rN12N = 2.233(15) Å, in gratifying agreement with ab initio calculations. Both the geometrical structure and the hyperfine coupling justify the conclusion that the CN group in gaseous sodium cyanide approximately can be considered as a free CN - ion.

Through tissue imaging of a live breast cancer tumour model using handheld surface enhanced spatially offset resonance Raman spectroscopy (SESORRS).

PubMed

Nicolson, Fay; Jamieson, Lauren E; Mabbott, Samuel; Plakas, Konstantinos; Shand, Neil C; Detty, Michael R; Graham, Duncan; Faulds, Karen

2018-04-21

In order to improve patient survival and reduce the amount of unnecessary and traumatic biopsies, non-invasive detection of cancerous tumours is of imperative and urgent need. Multicellular tumour spheroids (MTS) can be used as an ex vivo cancer tumour model, to model in vivo nanoparticle (NP) uptake by the enhanced permeability and retention (EPR) effect. Surface enhanced spatially offset Raman spectroscopy (SESORS) combines both surface enhanced Raman spectroscopy (SERS) and spatially offset Raman spectroscopy (SORS) to yield enhanced Raman signals at much greater sub-surface levels. By utilizing a reporter that has an electronic transition in resonance with the laser frequency, surface enhanced resonance Raman scattering (SERRS) yields even greater enhancement in Raman signal. Using a handheld SORS spectrometer with back scattering optics, we demonstrate the detection of live breast cancer 3D MTS containing SERRS active NPs through 15 mm of porcine tissue. False color 2D heat intensity maps were used to determine tumour model location. In addition, we demonstrate the tracking of SERRS-active NPs through porcine tissue to depths of up to 25 mm. This unprecedented performance is due to the use of red-shifted chalcogenpyrylium-based Raman reporters to demonstrate the novel technique of surface enhanced spatially offset resonance Raman spectroscopy (SESORRS) for the first time. Our results demonstrate a significant step forward in the ability to detect vibrational fingerprints from a tumour model at depth through tissue. Such an approach offers significant promise for the translation of NPs into clinical applications for non-invasive disease diagnostics based on this new chemical principle of measurement.

Quantification of vascular damage in acute kidney injury with fluorine magnetic resonance imaging and spectroscopy.

PubMed

Moore, Jeremy K; Chen, Junjie; Pan, Hua; Gaut, Joseph P; Jain, Sanjay; Wickline, Samuel A

2018-06-01

To design a fluorine MRI/MR spectroscopy approach to quantify renal vascular damage after ischemia-reperfusion injury, and the therapeutic response to antithrombin nanoparticles (NPs) to protect kidney function. A total of 53 rats underwent 45 min of bilateral renal artery occlusion and were treated at reperfusion with either plain perfluorocarbon NPs or NPs functionalized with a direct thrombin inhibitor (PPACK:phenyalanine-proline-arginine-chloromethylketone). Three hours after reperfusion, kidneys underwent ex vivo fluorine MRI/MR spectroscopy at 4.7 T to quantify the extent and volume of trapped NPs, as an index of vascular damage and ischemia-reperfusion injury. Microscopic evaluation of structural damage and NP trapping in non-reperfused renal segments was performed. Serum creatinine was quantified serially over 7 days. The damaged renal cortico-medullary junction trapped a significant volume of NPs (P = 0.04), which correlated linearly (r = 0.64) with the severity of kidney injury 3 h after reperfusion. Despite global large vessel reperfusion, non-reperfusion in medullary peritubular capillaries was confirmed by MRI and microscopy, indicative of continuing hypoxia due to vascular compromise. Treatment of animals with PPACK NPs after acute kidney injury did not accelerate kidney functional recovery. Quantification of ischemia-reperfusion injury after acute kidney injury with fluorine MRI/MR spectroscopy of perfluorocarbon NPs objectively depicts the extent and severity of vascular injury and its linear relationship to renal dysfunction. The lack of kidney function improvement after early posttreatment thrombin inhibition confirms the rapid onset of ischemia-reperfusion injury as a consequence of vascular damage and non-reperfusion. The prolongation of medullary ischemia renders cortico-medullary tubular structures susceptible to continued necrosis despite restoration of large vessel flow, which suggests limitations to acute interventions after

Resonant ultrasound spectroscopy for materials with high damping and samples of arbitrary geometry

DOE PAGES

Remillieux, Marcel C.; Ulrich, T. J.; Payan, Cédric; ...

2015-07-23

This paper describes resonant ultrasound spectroscopy (RUS) as a powerful and established technique for measuring elastic constants of a material with general anisotropy. The first step of this technique consists of extracting resonance frequencies and damping from the vibrational frequency spectrum measured on a sample with free boundary conditions. An inversion technique is then used to retrieve the elastic tensor from the measured resonance frequencies. As originally developed, RUS has been mostly applicable to (i) materials with small damping such that the resonances of the sample are well separated and (ii) samples with simple geometries for which analytical solutions exist.more » In this paper, these limitations are addressed with a new RUS approach adapted to materials with high damping and samples of arbitrary geometry. Resonances are extracted by fitting a sum of exponentially damped sinusoids to the measured frequency spectrum. The inversion of the elastic tensor is achieved with a genetic algorithm, which allows searching for a global minimum within a discrete and relatively wide solution space. First, the accuracy of the proposed approach is evaluated against numerical data simulated for samples with isotropic symmetry and transversely isotropic symmetry. Subsequently, the applicability of the approach is demonstrated using experimental data collected on a composite structure consisting of a cylindrical sample of Berea sandstone glued to a large piezoelectric disk. In the proposed experiments, RUS is further enhanced by the use of a 3-D laser vibrometer allowing the visualization of most of the modes in the frequency band studied.« less

Variable Permanent Magnet Quadrupole

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

Mihara, T.; Iwashita, Y.; /Kyoto U.

A permanent magnet quadrupole (PMQ) is one of the candidates for the final focus lens in a linear collider. An over 120 T/m strong variable permanent magnet quadrupole is achieved by the introduction of saturated iron and a 'double ring structure'. A fabricated PMQ achieved 24 T integrated gradient with 20 mm bore diameter, 100 mm magnet diameter and 20 cm pole length. The strength of the PMQ is adjustable in 1.4 T steps, due to its 'double ring structure': the PMQ is split into two nested rings; the outer ring is sliced along the beam line into four partsmore » and is rotated to change the strength. This paper describes the variable PMQ from fabrication to recent adjustments.« less

Proton magnetic resonance spectroscopy in ecstasy (MDMA) users.

PubMed

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

2004-05-20

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

Fingerprinting redox and ligand states in haemprotein crystal structures using resonance Raman spectroscopy.

PubMed

Kekilli, Demet; Dworkowski, Florian S N; Pompidor, Guillaume; Fuchs, Martin R; Andrew, Colin R; Antonyuk, Svetlana; Strange, Richard W; Eady, Robert R; Hasnain, S Samar; Hough, Michael A

2014-05-01

It is crucial to assign the correct redox and ligand states to crystal structures of proteins with an active redox centre to gain valid functional information and prevent the misinterpretation of structures. Single-crystal spectroscopies, particularly when applied in situ at macromolecular crystallography beamlines, allow spectroscopic investigations of redox and ligand states and the identification of reaction intermediates in protein crystals during the collection of structural data. Single-crystal resonance Raman spectroscopy was carried out in combination with macromolecular crystallography on Swiss Light Source beamline X10SA using cytochrome c' from Alcaligenes xylosoxidans. This allowed the fingerprinting and validation of different redox and ligand states, identification of vibrational modes and identification of intermediates together with monitoring of radiation-induced changes. This combined approach provides a powerful tool to obtain complementary data and correctly assign the true oxidation and ligand state(s) in redox-protein crystals.

Real-time process monitoring in a semi-continuous fluid-bed dryer - microwave resonance technology versus near-infrared spectroscopy.

PubMed

Peters, Johanna; Teske, Andreas; Taute, Wolfgang; Döscher, Claas; Höft, Michael; Knöchel, Reinhard; Breitkreutz, Jörg

2018-02-15

The trend towards continuous manufacturing in the pharmaceutical industry is associated with an increasing demand for advanced control strategies. It is a mandatory requirement to obtain reliable real-time information on critical quality attributes (CQA) during every process step as the decision on diversion of material needs to be performed fast and automatically. Where possible, production equipment should provide redundant systems for in-process control (IPC) measurements to ensure continuous process monitoring even if one of the systems is not available. In this paper, two methods for real-time monitoring of granule moisture in a semi-continuous fluid-bed drying unit are compared. While near-infrared (NIR) spectroscopy has already proven to be a suitable process analytical technology (PAT) tool for moisture measurements in fluid-bed applications, microwave resonance technology (MRT) showed difficulties to monitor moistures above 8% until recently. The results indicate, that the newly developed MRT sensor operating at four resonances is capable to compete with NIR spectroscopy. While NIR spectra were preprocessed by mean centering and first derivative before application of partial least squares (PLS) regression to build predictive models (RMSEP = 0.20%), microwave moisture values of two resonances sufficed to build a statistically close multiple linear regression (MLR) model (RMSEP = 0.07%) for moisture prediction. Thereby, it could be verified that moisture monitoring by MRT sensor systems could be a valuable alternative to NIR spectroscopy or could be used as a redundant system providing great ease of application. Copyright © 2017 Elsevier B.V. All rights reserved.

Measurement of Antioxidant Capacity by Electron Spin Resonance Spectroscopy Based on Copper(II) Reduction.

PubMed

Li, Dan; Jiang, Jia; Han, Dandan; Yu, Xinyu; Wang, Kun; Zang, Shuang; Lu, Dayong; Yu, Aimin; Zhang, Ziwei

2016-04-05

A new method is proposed for measuring the antioxidant capacity by electron spin resonance spectroscopy based on the loss of electron spin resonance signal after Cu(2+) is reduced to Cu(+) with antioxidant. Cu(+) was removed by precipitation in the presence of SCN(-). The remaining Cu(2+) was coordinated with diethyldithiocarbamate, extracted into n-butanol and determined by electron spin resonance spectrometry. Eight standards widely used in antioxidant capacity determination, including Trolox, ascorbic acid, ferulic acid, rutin, caffeic acid, quercetin, chlorogenic acid, and gallic acid were investigated. The standard curves for determining the eight standards were plotted, and results showed that the linear regression correlation coefficients were all high enough (r > 0.99). Trolox equivalent antioxidant capacity values for the antioxidant standards were calculated, and a good correlation (r > 0.94) between the values obtained by the present method and cupric reducing antioxidant capacity method was observed. The present method was applied to the analysis of real fruit samples and the evaluation of the antioxidant capacity of these fruits.

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

NASA Astrophysics Data System (ADS)

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

2012-07-01

A half-century quest for improving resolution in Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI) has enabled the study of molecular structures, biological interactions, and fine details of anatomy. This progress largely relied on the advent of sophisticated superconducting magnets that can provide stable and homogeneous fields with temporal and spatial variations below ΔB0/B0<0.01ppm. In many cases however, inherent properties of the objects under investigation, pulsating arteries, breathing lungs, tissue-air interfaces, surgical implants, etc., lead to fluctuations and losses of local homogeneity. A new method dubbed “long-lived-coherence correlation spectroscopy” (LLC-COSY) opens the way to overcome both inhomogeneous and homogeneous broadening, which arise from local variations in static fields and fluctuating dipole-dipole interactions, respectively. LLC-COSY makes it possible to obtain ultrahigh resolution two-dimensional spectra, with linewidths on the order of Δν=0.1 to 1 Hz, even in very inhomogeneous fields (ΔB0/B0>10ppm or 5000 Hz at 9.7 T), and can improve resolution by a factor up to 9 when the homogeneous linewidths are determined by dipole-dipole interactions. The resulting LLC-COSY spectra display chemical shift differences and scalar couplings in two orthogonal dimensions, like in “J spectroscopy.” LLC-COSY does not require any sophisticated gradient switching or frequency-modulated pulses. Applications to in-cell NMR and to magnetic resonance spectroscopy (MRS) of selected volume elements in MRI appear promising, particularly when susceptibility variations tend to preclude high resolution.

Resonance Raman Spectroscopy of human brain metastasis of lung cancer analyzed by blind source separation

NASA Astrophysics Data System (ADS)

Zhou, Yan; Liu, Cheng-Hui; Pu, Yang; Cheng, Gangge; Yu, Xinguang; Zhou, Lixin; Lin, Dongmei; Zhu, Ke; Alfano, Robert R.

2017-02-01

Resonance Raman (RR) spectroscopy offers a novel Optical Biopsy method in cancer discrimination by a means of enhancement in Raman scattering. It is widely acknowledged that the RR spectrum of tissue is a superposition of spectra of various key building block molecules. In this study, the Resonance Raman (RR) spectra of human metastasis of lung cancerous and normal brain tissues excited by a visible selected wavelength at 532 nm are used to explore spectral changes caused by the tumor evolution. The potential application of RR spectra human brain metastasis of lung cancer was investigated by Blind Source Separation such as Principal Component Analysis (PCA). PCA is a statistical procedure that uses an orthogonal transformation to convert a set of observations of possibly correlated variables into a set of values of linearly uncorrelated variables called principal components (PCs). The results show significant RR spectra difference between human metastasis of lung cancerous and normal brain tissues analyzed by PCA. To evaluate the efficacy of for cancer detection, a linear discriminant analysis (LDA) classifier is utilized to calculate the sensitivity, and specificity and the receiver operating characteristic (ROC) curves are used to evaluate the performance of this criterion. Excellent sensitivity of 0.97, specificity (close to 1.00) and the Area Under ROC Curve (AUC) of 0.99 values are achieved under best optimal circumstance. This research demonstrates that RR spectroscopy is effective for detecting changes of tissues due to the development of brain metastasis of lung cancer. RR spectroscopy analyzed by blind source separation may have potential to be a new armamentarium.

Characterization and discrimination of human breast cancer and normal breast tissues using resonance Raman spectroscopy

NASA Astrophysics Data System (ADS)

Wu, Binlin; Smith, Jason; Zhang, Lin; Gao, Xin; Alfano, Robert R.

2018-02-01

Worldwide breast cancer incidence has increased by more than twenty percent in the past decade. It is also known that in that time, mortality due to the affliction has increased by fourteen percent. Using optical-based diagnostic techniques, such as Raman spectroscopy, has been explored in order to increase diagnostic accuracy in a more objective way along with significantly decreasing diagnostic wait-times. In this study, Raman spectroscopy with 532-nm excitation was used in order to incite resonance effects to enhance Stokes Raman scattering from unique biomolecular vibrational modes. Seventy-two Raman spectra (41 cancerous, 31 normal) were collected from nine breast tissue samples by performing a ten-spectra average using a 500-ms acquisition time at each acquisition location. The raw spectral data was subsequently prepared for analysis with background correction and normalization. The spectral data in the Raman Shift range of 750- 2000 cm-1 was used for analysis since the detector has highest sensitivity around in this range. The matrix decomposition technique nonnegative matrix factorization (NMF) was then performed on this processed data. The resulting leave-oneout cross-validation using two selective feature components resulted in sensitivity, specificity and accuracy of 92.6%, 100% and 96.0% respectively. The performance of NMF was also compared to that using principal component analysis (PCA), and NMF was shown be to be superior to PCA in this study. This study shows that coupling the resonance Raman spectroscopy technique with subsequent NMF decomposition method shows potential for high characterization accuracy in breast cancer detection.

Clinical perspectives of hybrid proton-fluorine magnetic resonance imaging and spectroscopy.

PubMed

Wolters, Martijn; Mohades, Seyede G; Hackeng, Tilman M; Post, Mark J; Kooi, Marianne E; Backes, Walter H

2013-05-01

The number of applications of fluorine 19 (19F) magnetic resonance (MR) imaging and spectroscopy in biomedical and clinical research is steadily growing. The 100% natural abundance of fluorine and its relatively high sensitivity for MR (83% to that of protons) make it an interesting nucleus for a wide range of MR applications. Fluorinated contrast media have a number of advantages over the conventionally used gadolinium-based or iron-based contrast agents. The absence of an endogenous fluorine background intensity in the human body facilitates reliable quantification of fluorinated contrast medium or drugs. Anatomy can be visualized separately with proton MR imaging, creating the application of hybrid hydrogen 1 (1H)/19F MR imaging. The availability of 2 channels (ie, the 1H and 19F channels) enables dual-targeted molecular imaging. Recently, novel developments have emerged on fluorine-based contrast media in preclinical studies and imaging techniques. The developments in fluorine MR seem promising for clinical applications, with contributions in therapy monitoring, assessment of lung function, angiography, and molecular imaging. This review outlines the translation from recent advances in preclinical MR imaging and spectroscopy to future perspectives of clinical hybrid 1H/19/F MR imaging applications.

Chiral NNLOsat descriptions of nuclear multipole resonances within the random-phase approximation

NASA Astrophysics Data System (ADS)

Wu, Q.; Hu, B. S.; Xu, F. R.; Ma, Y. Z.; Dai, S. J.; Sun, Z. H.; Jansen, G. R.

2018-05-01

We study nuclear multipole resonances in the framework of the random-phase approximation by using the chiral potential NNLOsat. This potential includes two- and three-body terms that have been simultaneously optimized to low-energy nucleon-nucleon scattering data and selected nuclear structure data. Our main focuses have been the isoscalar monopole, isovector dipole, and isoscalar quadrupole resonances of the closed-shell nuclei, 4He, O 16 ,22 ,24 , and Ca,4840. These resonance modes have been widely observed in experiment. In addition, we use a renormalized chiral potential Vlow-k, based on the N3LO two-body potential by Entem and Machleidt [Phys. Rev. C 68, 041001 (2011), 10.1103/PhysRevC.68.041001]. This introduces a dependency on the cutoff parameter used in the normalization procedure as reported in previous works by other groups. While NNLOsat can reasonably reproduce observed multipole resonances, it is not possible to find a single cutoff parameter for the Vlow-k potential that simultaneously describes the different types of resonance modes. The sensitivity to the cutoff parameter can be explained by missing induced three-body forces in the calculations. Our results for neutron-rich O,2422 show a mixing nature of isoscalar and isovector resonances in the dipole channel at low energies. We predict that 22O and 24O have low-energy isoscalar quadrupole resonances at energies lower than 5 MeV.

Surface-Enhanced Resonance Raman Scattering and Visible Extinction Spectroscopy of Copper Chlorophyllin: An Upper Level Chemistry Experiment

ERIC Educational Resources Information Center

Schnitzer, Cheryl S.; Reim, Candace Lawson; Sirois, John J.; House, Paul G.

2010-01-01

Advanced chemistry students are introduced to surface-enhanced resonance Raman scattering (SERRS) by studying how sodium copper chlorophyllin (CuChl) adsorbs onto silver colloids (CuChl/Ag) as a function of pH. Using both SERRS and visible extinction spectroscopy, the extent of CuChl adsorption and colloidal aggregation are monitored. Initially at…

Electron beam imaging and spectroscopy of plasmonic nanoantenna resonances

NASA Astrophysics Data System (ADS)

Vesseur, E. J. R.

2011-07-01

Nanoantennas are metal structures that provide strong optical coupling between a nanoscale volume and the far field. This coupling is mediated by surface plasmons, oscillations of the free electrons in the metal. Increasing the control over the resonant plasmonic field distribution opens up a wide range of applications of nanoantennas operating both in receiving and transmitting mode. This thesis presents how the dispersion and confinement of surface plasmons in nanoantennas are resolved and further engineered. Fabrication of nanostructures is done using focused ion beam milling (FIB) in metallic surfaces. We demonstrate that patterning in single-crystal substrates allows us to precisely control the geometry in which plasmons are confined. The nanoscale properties of the resonant plasmonic fields are resolved using a new technique developed in this thesis: angle- and polarization controlled cathodoluminescence (CL) imaging spectroscopy. The use of a tightly focused electron beam allows us to probe the optical antenna properties with deep subwavelength resolution. We show using this technique that nanoantennas consisting of 500-1200 nm long polycrystalline Au nanowires support standing plasmon waves. We directly observe the plasmon wavelengths which we use to derive the dispersion relation of guided nanowire plasmons. A 590-nm-long ridge-shaped nanoantenna was fabricated using FIB milling on a single-crystal Au substrate, demonstrating a level of control over the fabrication impossible with polycrystalline metals. CL experiments show that the ridge supports multiple-order resonances. The confinement of surface plasmons to the ridge is confirmed by boundary-element-method (BEM) calculations. The resonant modes in plasmonic whispering gallery cavities consisting of a FIB-fabricated circular groove are resolved. We find an excellent agreement between boundary element method calculations and the measured CL emission from the ring-shaped cavities. The calculations show

Stability of an aqueous quadrupole micro-trap

DOE PAGES

Park, Jae Hyun; Krstić, Predrag S.

2012-03-30

Recently demonstrated functionality of an aqueous quadrupole micro- or nano-trap opens a new avenue for applications of the Paul traps, like is confinement of a charged biomolecule which requires water environment for its chemical stability. Besides strong viscosity forces, motion of a charged particle in the aqueous trap is subject to dielectrophoretic and electrophoretic forces. In this study, we describe the general conditions for stability of a charged particle in an aqueous quadrupole trap. We find that for the typical micro-trap parameters, effects of both dielectrophoresis and electrophoresis significantly influence the trap stability. In particular, the aqueous quadrupole trap couldmore » play of a role of a synthetic virtual nanopore for the 3rd generation of DNA sequencing technology.« less

Integration of 3D 1H-magnetic resonance spectroscopy data into neuronavigation systems for tumor biopsies

NASA Astrophysics Data System (ADS)

Kanberoglu, Berkay; Moore, Nina Z.; Frakes, David; Karam, Lina J.; Debbins, Josef P.; Preul, Mark C.

2013-03-01

Many important applications in clinical medicine can benefit from the fusion of spectroscopy data with anatomical images. For example, the correlation of metabolite profiles with specific regions of interest in anatomical tumor images can be useful in characterizing and treating heterogeneous tumors that appear structurally homogeneous. Such applications can build on the correlation of data from in-vivo Proton Magnetic Resonance Spectroscopy Imaging (1HMRSI) with data from genetic and ex-vivo Nuclear Magnetic Resonance spectroscopy. To establish that correlation, tissue samples must be neurosurgically extracted from specifically identified locations with high accuracy. Toward that end, this paper presents new neuronavigation technology that enhances current clinical capabilities in the context of neurosurgical planning and execution. The proposed methods improve upon the current state-of-the-art in neuronavigation through the use of detailed three dimensional (3D) 1H-MRSI data. MRSI spectra are processed and analyzed, and specific voxels are selected based on their chemical contents. 3D neuronavigation overlays are then generated and applied to anatomical image data in the operating room. Without such technology, neurosurgeons must rely on memory and other qualitative resources alone for guidance in accessing specific MRSI-identified voxels. In contrast, MRSI-based overlays provide quantitative visual cues and location information during neurosurgery. The proposed methods enable a progressive new form of online MRSI-guided neuronavigation that we demonstrate in this study through phantom validation and clinical application.

Elevated prefrontal cortex γ-aminobutyric acid and glutamate-glutamine levels in schizophrenia measured in vivo with proton magnetic resonance spectroscopy.

PubMed

Kegeles, Lawrence S; Mao, Xiangling; Stanford, Arielle D; Girgis, Ragy; Ojeil, Najate; Xu, Xiaoyan; Gil, Roberto; Slifstein, Mark; Abi-Dargham, Anissa; Lisanby, Sarah H; Shungu, Dikoma C

2012-05-01

Postmortem studies have found evidence of γ-aminobutyric acid (GABA) deficits in fast-spiking, parvalbumin-positive interneurons in the prefrontal cortex in schizophrenia. Magnetic resonance spectroscopy studies in unmedicated patients have reported glutamine or glutamate-glutamine (Glx) elevations in this region. Abnormalities in these transmitters are thought to play a role in cognitive impairments in the illness. To measure GABA and Glx levels in vivo in 2 prefrontal brain regions in unmedicated and medicated patients with schizophrenia and healthy controls. Case-control study. Inpatient psychiatric research unit and associated outpatient clinic. Sixteen unmedicated patients with schizophrenia, 16 medicated patients, and 22 healthy controls matched for age, sex, ethnicity, parental socioeconomic status, and cigarette smoking. Proton magnetic resonance spectroscopy with a 3-T system and the J-edited spin-echo difference method. The GABA and Glx levels were measured in the dorsolateral and medial prefrontal cortex and normalized to the simultaneously acquired water signal. Working memory performance was assessed in all subjects. The GABA and Glx concentrations determined by proton magnetic resonance spectroscopy. In the medial prefrontal cortex region, 30% elevations were found in GABA (P = .02) and Glx (P = .03) levels in unmedicated patients compared with controls. There were no alterations in the medicated patients or in either group in the dorsolateral prefrontal cortex. Both regions showed correlations between GABA and Glx levels in patients and controls. No correlations with working memory performance were found. To our knowledge, this study presents the first GABA concentration measurements in unmedicated patients with schizophrenia, who showed elevations in both GABA and Glx levels in the medial prefrontal cortex but not the dorsolateral prefrontal cortex. Medicated patients did not show these elevations, suggesting possible normalization of levels with

Brain Biochemistry and Personality: A Magnetic Resonance Spectroscopy Study

PubMed Central

Ryman, Sephira G.; Gasparovic, Chuck; Bedrick, Edward J.; Flores, Ranee A.; Marshall, Alison N.; Jung, Rex E.

2011-01-01

To investigate the biochemical correlates of normal personality we utilized proton magnetic resonance spectroscopy (1H-MRS). Our sample consisted of 60 subjects ranging in age from 18 to 32 (27 females). Personality was assessed with the NEO Five-Factor Inventory (NEO-FFI). We measured brain biochemistry within the precuneus, the cingulate cortex, and underlying white matter. We hypothesized that brain biochemistry within these regions would predict individual differences across major domains of personality functioning. Biochemical models were fit for all personality domains including Neuroticism, Extraversion, Openness, Agreeableness, and Conscientiousness. Our findings involved differing concentrations of Choline (Cho), Creatine (Cre), and N-acetylaspartate (NAA) in regions both within (i.e., posterior cingulate cortex) and white matter underlying (i.e., precuneus) the Default Mode Network (DMN). These results add to an emerging literature regarding personality neuroscience, and implicate biochemical integrity within the default mode network as constraining major personality domains within normal human subjects. PMID:22073190

Multivoxel proton magnetic resonance spectroscopy in facioscapulohumeral muscular dystrophy.

PubMed

Leung, Doris G; Wang, Xin; Barker, Peter B; Carrino, John A; Wagner, Kathryn R

2018-06-01

Facioscapulohumeral muscular dystrophy (FSHD) is a hereditary disorder that causes progressive muscle wasting. This study evaluates the use of proton magnetic resonance spectroscopy ( 1 H MRS) as a biomarker of muscle strength and function in FSHD. Thirty-six individuals with FSHD and 15 healthy controls underwent multivoxel 1 H MRS of a cross-section of the mid-thigh. Concentrations of creatine, intramyocellular and extramyocellular lipids, and trimethylamine (TMA)-containing compounds in skeletal muscle were calculated. Metabolite concentrations for individuals with FSHD were compared with those of controls. The relationship between metabolite concentrations and muscle strength was also examined. The TMA/creatine (Cr) ratio in individuals with FSHD was reduced compared with controls. The TMA/Cr ratio in the hamstrings also showed a moderate linear correlation with muscle strength. 1 H MRS offers a potential method of detecting early muscle pathology in FSHD prior to the development of fat infiltration. Muscle Nerve 57: 958-963, 2018. © 2017 Wiley Periodicals, Inc.

Cytochrome c at charged interfaces studied by resonance Raman and surface-enhanced resonance Raman spectroscopy

NASA Astrophysics Data System (ADS)

Hildebrandt, Peter

1991-05-01

The effect of electrostatic fields on the structure of cytochrome c bound to charged interfaces was studied by resonance Raman and surface enhanced resonance Raman spectroscopy. Binding of this heme protein to the Ag electrode or heteropolytungstates which may be regarded as simple model systems for biological interfaces establishes an equilibrium between two conformational states (I II). In state I the structure and the redox potential are the same as for the uncomplexed cytochrome c. In state II however the heme pocket assumes an open structure and the axial iron Met80 bond is weakened leading to thennal coordination equilibrium between the fivecoordinated high spin and the sixcoordinated low spin configuration. These structural changes are accompanied by a decrease of the redox potential by 420 mV. The structural rearrangement of the heme pocket in state II is presumably initiated by the dissociation of the internal salt bridge of Lys13 due to electrostatic interactions with the negatively charged surfaces of the model systems. From detailed Raman spectroscopic studies characteristic spectral properties of the states I and II were identified. Based on these findings the interactions of cytochrome c with phospholipid vesicles as well as with its physiological reaction partner cytocbrome c oxidase were analysed. A systematic study of the cytochmme c/phospholipid system by varying the lipid composition and the temperature revealed mutual structural changes in both the lipid and the protein structure.

Direct Imaging of Transient Fano Resonances in N_{2} Using Time-, Energy-, and Angular-Resolved Photoelectron Spectroscopy.

PubMed

Eckstein, Martin; Yang, Chung-Hsin; Frassetto, Fabio; Poletto, Luca; Sansone, Giuseppe; Vrakking, Marc J J; Kornilov, Oleg

2016-04-22

Autoionizing Rydberg states of molecular N_{2} are studied using time-, energy-, and angular-resolved photoelectron spectroscopy. A femtosecond extreme ultraviolet pulse with a photon energy of 17.5 eV excites the resonance and a subsequent IR pulse ionizes the molecule before the autoionization takes place. The angular-resolved photoelectron spectra depend on pump-probe time delay and allow for the distinguishing of two electronic states contributing to the resonance. The lifetime of one of the contributions is determined to be 14±1  fs, while the lifetime of the other appears to be significantly shorter than the time resolution of the experiment. These observations suggest that the Rydberg states in this energy region are influenced by the effect of interference stabilization and merge into a complex resonance.

Dynamic quadrupole interactions in semiconductors

NASA Astrophysics Data System (ADS)

Dang, Thien Thanh; Schell, Juliana; Lupascu, Doru C.; Vianden, Reiner

2018-04-01

The time differential perturbed angular correlation, TDPAC, technique has been used for several decades to study electric quadrupole hyperfine interactions in semiconductors such as dynamic quadrupole interactions (DQI) resulting from after-effects of the nuclear decay as well as static quadrupole interactions originating from static defects around the probe nuclei such as interstitial ions, stresses in the crystalline structure, and impurities. Nowadays, the quality of the available semiconductor materials is much better, allowing us to study purely dynamic interactions. We present TDPAC measurements on pure Si, Ge, GaAs, and InP as a function of temperature between 12 K and 110 K. The probe 111In (111Cd) was used. Implantation damage was recovered by thermal annealing. Si experienced the strongest DQI with lifetime, τg, increasing with rising temperature, followed by Ge. In contrast, InP and GaAs, which have larger band gaps and less electron concentration than Si and Ge in the same temperature range, presented no DQI. The results obtained also allow us to conclude that indirect band gap semiconductors showed the dynamic interaction, whereas the direct band gap semiconductors, restricted to GaAs and InP, did not.

Beyond static measures: A review of functional magnetic resonance spectroscopy and its potential to investigate dynamic glutamatergic abnormalities in schizophrenia.

PubMed

Jelen, Luke A; King, Sinead; Mullins, Paul G; Stone, James M

2018-05-01

Abnormalities of the glutamate system are increasingly implicated in schizophrenia but their exact nature remains unknown. Proton magnetic resonance spectroscopy ( 1 H-MRS), while fundamental in revealing glutamatergic alterations in schizophrenia, has, until recently, been significantly limited and thought to only provide static measures. Functional magnetic resonance spectroscopy (fMRS), which uses sequential scans for dynamic measurement of a range of brain metabolites in activated brain areas, has lately been applied to a variety of task or stimulus conditions, producing interesting insights into neurometabolite responses to neural activation. Here, we summarise the existing 1 H-MRS studies of brain glutamate in schizophrenia. We then present a comprehensive review of research studies that have utilised fMRS, and lastly consider how fMRS methods might further the understanding of glutamatergic abnormalities in schizophrenia.

Microfluidic quadrupole and floating concentration gradient.

PubMed

Qasaimeh, Mohammad A; Gervais, Thomas; Juncker, David

2011-09-06

The concept of fluidic multipoles, in analogy to electrostatics, has long been known as a particular class of solutions of the Navier-Stokes equation in potential flows; however, experimental observations of fluidic multipoles and of their characteristics have not been reported yet. Here we present a two-dimensional microfluidic quadrupole and a theoretical analysis consistent with the experimental observations. The microfluidic quadrupole was formed by simultaneously injecting and aspirating fluids from two pairs of opposing apertures in a narrow gap formed between a microfluidic probe and a substrate. A stagnation point was formed at the centre of the microfluidic quadrupole, and its position could be rapidly adjusted hydrodynamically. Following the injection of a solute through one of the poles, a stationary, tunable, and movable-that is, 'floating'-concentration gradient was formed at the stagnation point. Our results lay the foundation for future combined experimental and theoretical exploration of microfluidic planar multipoles including convective-diffusive phenomena.

Reduced anterior cingulate glutamate in pediatric major depression: a magnetic resonance spectroscopy study.

PubMed

Rosenberg, David R; Macmaster, Frank P; Mirza, Yousha; Smith, Janet M; Easter, Phillip C; Banerjee, S Preeya; Bhandari, Rashmi; Boyd, Courtney; Lynch, Michelle; Rose, Michelle; Ivey, Jennifer; Villafuerte, Rosemond A; Moore, Gregory J; Renshaw, Perry

2005-11-01

Anterior cingulate cortex has been implicated in the pathogenesis of major depressive disorder (MDD). With single voxel proton magnetic resonance spectroscopy, we reported reductions in anterior cingulate glutamatergic concentrations (grouped value of glutamate and glutamine) in 14 pediatric MDD patients versus 14 case-matched healthy control subjects. These changes might reflect a change in glutamate, glutamine, or their combination. Fitting to individually quantify anterior cingulate glutamate and glutamine was performed in these subjects with a new basis set created from data acquired on a 1.5 Tesla General Electric Signa (GE Healthcare, Waukesha, Wisconsin) magnetic resonance imaging scanner with LCModel (Version 6.1-0; Max-Planck-Institute, Gottingen, Germany). Reduced anterior cingulate glutamate was observed in MDD patients versus control subjects (8.79 +/- 1.68 vs. 11.46 +/- 1.55, respectively, p = .0002; 23% decrease). Anterior cingulate glutamine did not differ significantly between patients with MDD and control subjects. These findings provide confirmatory evidence of anterior cingulate glutamate alterations in pediatric MDD.

Photodetachment spectroscopy and resonant photoelectron imaging of cryogenically-cooled deprotonated 2-hydroxypyrimidine anions

NASA Astrophysics Data System (ADS)

Huang, Dao-Ling; Zhu, Guo-Zhu; Liu, Yuan; Wang, Lai-Sheng

2017-02-01

We report a photodetachment and high-resolution photoelectron imaging study of cold deprotonated 2-hydroxypyrimidine anions, C4H3N2O-. Photodetachment spectroscopy reveals an excited dipole-bound state (DBS) of C4H3N2O- with a binding energy of 598 ± 5 cm-1 below the detachment threshold of 26,010 ± 5 cm-1. Twenty vibrational levels of the DBS are observed as resonances in the photodetachment spectrum, with three below the detachment threshold and seventeen above the threshold. By tuning the detachment laser to the above-threshold vibrational resonances, highly non-Franck-Condon photoelectron spectra are obtained. Nine fundamental vibrational frequencies are resolved, including six symmetry-forbidden modes. The 598 cm-1 binding energy for the DBS is quite high due to the large dipole moment of the C4H3N2Orad (>6 D). However, no evidence of a second DBS is observed below the detachment threshold.

Correcting reaction rates measured by saturation-transfer magnetic resonance spectroscopy

NASA Astrophysics Data System (ADS)

Gabr, Refaat E.; Weiss, Robert G.; Bottomley, Paul A.

2008-04-01

Off-resonance or spillover irradiation and incomplete saturation can introduce significant errors in the estimates of chemical rate constants measured by saturation-transfer magnetic resonance spectroscopy (MRS). Existing methods of correction are effective only over a limited parameter range. Here, a general approach of numerically solving the Bloch-McConnell equations to calculate exchange rates, relaxation times and concentrations for the saturation-transfer experiment is investigated, but found to require more measurements and higher signal-to-noise ratios than in vivo studies can practically afford. As an alternative, correction formulae for the reaction rate are provided which account for the expected parameter ranges and limited measurements available in vivo. The correction term is a quadratic function of experimental measurements. In computer simulations, the new formulae showed negligible bias and reduced the maximum error in the rate constants by about 3-fold compared to traditional formulae, and the error scatter by about 4-fold, over a wide range of parameters for conventional saturation transfer employing progressive saturation, and for the four-angle saturation-transfer method applied to the creatine kinase (CK) reaction in the human heart at 1.5 T. In normal in vivo spectra affected by spillover, the correction increases the mean calculated forward CK reaction rate by 6-16% over traditional and prior correction formulae.

Measuring the Magnetic Center Behavior of an ILC Superconducting Quadrupole Prototype

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

Spencer, Cherrill M.; Adolphsen, Chris; Berndt, Martin

2011-02-07

The main linacs of the proposed International Linear Collider (ILC) consist of superconducting cavities operated at 2K. The accelerating cavities are contained in a contiguous series of cryogenic modules that also house the main linac quadrupoles, thus the quadrupoles also need to be superconducting. In an early ILC design, these magnets are about 0.6 m long, have cos (2{theta}) coils, and operate at constant field gradients up to 60 T/m. In order to preserve the small beam emittances in the ILC linacs, the e+ and e- beams need to traverse the quadrupoles near their magnetic centers. A quadrupole shunting techniquemore » is used to measure the quadrupole alignment with the beams; this process requires the magnetic centers move by no more than about 5 micrometers when their strength is changed. To determine if such tight stability is achievable in a superconducting quadrupole, we at SLAC measured the magnetic center motions in a prototype ILC quadrupole built at CIEMAT in Spain. A rotating coil technique was used with a better than 0.1 micrometer precision in the relative field center position, and less than a 2 micrometer systematic error over 30 minutes. This paper describes the warm-bore cryomodule that houses the quadrupole in its Helium vessel, the magnetic center measurement system, the measured center data and strength and harmonics magnetic data.« less

1H NMR relaxometry and quadrupole relaxation enhancement as a sensitive probe of dynamical properties of solids—[C(NH2)3]3Bi2I9 as an example

NASA Astrophysics Data System (ADS)

Florek-Wojciechowska, M.; Wojciechowski, M.; Jakubas, R.; Brym, Sz.; Kruk, D.

2016-02-01

1H nuclear magnetic resonance relaxometry has been applied to reveal information on dynamics and structure of Gu3Bi2I9 ([Gu = C(NH2)3] denotes guanidinium cation). The data have been analyzed in terms of a theory of quadrupole relaxation enhancement, which has been extended here by including effects associated with quadrupole (14N) spin relaxation caused by a fast fluctuating component of the electric field gradient tensor. Two motional processes have been identified: a slow one occurring on a timescale of about 8 × 10-6 s which has turned out to be (almost) temperature independent, and a fast process in the range of 10-9 s. From the 1H-14N relaxation contribution (that shows "quadrupole peaks") the quadrupole parameters, which are a fingerprint of the arrangement of the anionic network, have been determined. It has been demonstrated that the magnitude of the quadrupole coupling considerably changes with temperature and the changes are not caused by phase transitions. At the same time, it has been shown that there is no evidence of abrupt changes in the cationic dynamics and the anionic substructure upon the phase transitions.

One Part Nuclear, One Part Solid State: Fifty Years of Mössbauer Spectroscopy

NASA Astrophysics Data System (ADS)

Westfall, Catherine

2004-05-01

Starting in 1955 Rudolf Mössbauer conducted experiments that would demonstrate in the next three years that an atomic nucleus in a crystal does not recoil when it emits a gamma ray and provides the entire emitted energy to the gamma ray. The resonance spectroscopy made possible by this discovery led to fifty years of scientific explorations in a wide variety of fields including nuclear and solid state physics, chemistry, and geology. At the current time, Mössbauer spectroscopy is a vital part of science programs, both in many laboratories and at world-class light sources, such as Argonnes Advanced Photon Source. This paper will focus on the history of multidisciplinary Mössbauer research at Argonne National Laboratory and particularly on the interaction between nuclear and condensed matter physicists. This was necessary because of the ultra-high energy resolution of the Mössbauer resonance with its ability to resolve hyperfine interactions between the nuclear moments (nuclear charge distribution, the nuclear magnetic moment, and nuclear quadrupole moment) and corresponding solid state properties (electron charge distribution at the nucleus, magnetic field at the nucleus, and electric field gradient at the nucleus.) Understanding and exploiting Mössbauer spectroscopy therefore required work at the intersection of nuclear and solid state physics and the skills and knowledge of both specialties. The paper will start with the discovery and confirmation of the Mössbauer effect. Then it will outline early important experiments, such as the use of Mössbauer spectroscopy to confirm Einsteins general theory of relativity, and give an overview of the rapid expansion of this research tool, first with the use of Fe57 and later with the use of other isotopes. In particular the paper will focus on Argonnes cutting-edge Mössbauer work on transuranics. This work built on the resources and expertise first developed at the laboratory during WWII and brought together not only

High Sensitivity Absorption Spectroscopy on Ti II VUV Resonance Lines of Astrophysical Interest

NASA Astrophysics Data System (ADS)

Wiese, Lm; Fedchak, Ja; Lawler, Je

2000-06-01

The neutral hydrogen regions of the Interstellar Medium (ISM) of our Galaxy and distant galaxies produce simple absorption spectra because most metals are singly ionized and in their ground fine structure level. Elemental abundance measurements and other studies of the ISM rely on accurate atomic oscillator strengths (f-values) for a few key lines in the second spectra of Ti and other metals. The Ti II VUV resonance lines at 1910.6 and 1910.9 Åare important in absorption line systems in which quasars provide the continuum and the ISM of intervening galaxies is observed. Some of these absorption line systems are redshifted to the visible and observed with ground based telescopes. We report the first laboratory measurement of these Ti II VUV resonance lines. Using High Sensitivity Absorption Spectroscopy, we determined f-values for the 1910 Ålines relative to well-known Ti II resonance lines at 3067 and 3384 ÅContinuum radiation from an Aladdin Storage Ring bending magnet at the Synchrotron Radiation Center (SRC) is passed through a discharge plasma containing Ti^+. The transmitted light is analyzed by our 3m vacuum echelle spectrometer equipped with VUV sensitive CCD array. The resolving power of our spectrometer/detector array is 300,000. F-values are determined to within 10%.

Discriminating the structure of exo-2-aminonorbornane using nuclear quadrupole coupling interactions.

PubMed

Écija, Patricia; Cocinero, Emilio J; Lesarri, Alberto; Millán, Judith; Basterretxea, Francisco; Fernández, José A; Castaño, Fernando

2011-04-28

The intrinsic conformational and structural properties of the bicycle exo-2-aminonorbornane have been probed in a supersonic jet expansion using Fourier-transform microwave (FT-MW) spectroscopy and quantum chemical calculations. The rotational spectrum revealed two different conformers arising from the internal rotation of the amino group, exhibiting small (MHz) hyperfine patterns originated by the (14)N nuclear quadrupole coupling interaction. Complementary ab initio (MP2) and DFT (B3LYP and M05-2X) calculations provided comparative predictions for the structural properties, rotational and centrifugal distortion data, hyperfine parameters, and isomerization barriers. Due to the similarity of the rotational constants, the structural assignment of the observed rotamers and the calculation of the torsion angles of the amino group were based on the conformational dependence of the (14)N nuclear quadrupole coupling hyperfine tensor. In the most stable conformation (ss), the two amino N-H bonds are staggered with respect to the adjacent C-H bond. In the second conformer (st), only one of the N-H bonds is staggered and the other is trans. A third predicted conformer (ts) was not detected, consistent with a predicted conformational relaxation to conformer ss through a low barrier of 5.2 kJ mol(-1).

Nature of isomerism of solid isothiourea salts, inhibitors of nitric oxide synthases, as studied by 1H-14N nuclear quadrupole double resonance, X-ray, and density functional theory/quantum theory of atoms in molecules.

PubMed

Latosińska, J N; Latosińska, M; Seliger, J; Žagar, V; Maurin, J K; Kazimierczuk, Z

2012-02-09

Isothioureas, inhibitors of nitric oxide synthases, have been studied experimentally in solid state by nuclear quadrupole double resonance (NQDR) and X-ray methods and theoretically by the quantum theory of atoms in molecules/density functional theory. Resonance frequencies on (14)N have been detected and assigned to particular nitrogen sites in each molecule. The crystal packings of (S)-3,4-dichlorobenzyl-N-methylisothiouronium chloride with the disordered chlorine positions in benzene ring and (S)-butyloisothiouronium bromide have been resolved in X-ray diffraction studies. (14)N NQDR spectra have been found good indicators of isomer type and strength of intra- or intermolecular N-H···X (X = Cl, Br) interactions. From among all salts studied, only for (S)-2,3,4,5,6-pentabromobenzylisothiouronium chloride are both nitrogen sites equivalent, which has been explained by the slow exchange. This unique structural feature can be a key factor in the high biological activity of (S)-2,3,4,5,6-pentabromobenzylisothiouronium salts.

Raman Spectroscopy.

ERIC Educational Resources Information Center

Gerrard, Donald L.

1984-01-01

Reviews literature on Raman spectroscopy from late 1981 to late 1983. Topic areas include: instrumentation and sampling; liquids and solutions; gases and matrix isolation; biological molecules; polymers; high-temperature and high-pressure studies; Raman microscopy; thin films and surfaces; resonance-enhanced and surface-enhanced spectroscopy; and…

Characterisation of β-tricalcium phosphate-based bone substitute materials by electron paramagnetic resonance spectroscopy

NASA Astrophysics Data System (ADS)

Matković, Ivo; Maltar-Strmečki, Nadica; Babić-Ivančić, Vesna; Dutour Sikirić, Maja; Noethig-Laslo, Vesna

2012-10-01

β-TCP based materials are frequently used as dental implants. Due to their resorption in the body and direct contact with tissues, in order to inactivate bacteria, fungal spores and viruses, they are usually sterilized by γ-irradiation. However, the current literature provides little information about effects of the γ-irradiation on the formation and stability of the free radicals in the bone graft materials during and after sterilization procedure. In this work five different bone graft substitution materials, composed of synthetic beta tricalcium phosphate (β-TCP) and hydroxyapatite (HAP) present in the market were characterized by electron paramagnetic resonance (EPR) spectroscopy, X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Paramagnetic species Mn2+, Fe3+, trapped H-atoms and CO2- radicals were detected in the biphasic material (60% HAP, 40% β-TCP), while in β-TCP materials only Mn2+ andor trapped hydrogen atoms were detected. EPR analysis revealed the details of the structure of these materials at the atomic level. The results have shown that EPR spectroscopy is a method which can be used to improve the quality control of bone graft materials after syntering, processing and sterilization procedure.

Photolytic interruptions of the bacteriorhodopsin photocycle examined by time-resolved resonance raman spectroscopy.

PubMed

Grieger, I; Atkinson, G H

1985-09-24

An investigation of the photolytic conditions used to initiate and spectroscopically monitor the bacteriorhodopsin (BR) photocycle utilizing time-resolved resonance Raman (TR3) spectroscopy has revealed and characterized two photoinduced reactions that interrupt the thermal pathway. One reaction involves the photolytic interconversion of M-412 and M', and the other involves the direct photolytic conversion of the BR-570/K-590 photostationary mixture either to M-412 and M' or to M-like intermediates within 10 ns. The photolytic threshold conditions describing both reactions have been quantitatively measured and are discussed in terms of experimental parameters.

The argon nuclear quadrupole moments

NASA Astrophysics Data System (ADS)

Sundholm, Dage; Pyykkö, Pekka

2018-07-01

New standard values -116(2) mb and 76(3) mb are suggested for the nuclear quadrupole moments (Q) of the 39Ar and 37Ar nuclei, respectively. The Q values were obtained by combining optical measurements of the quadrupole coupling constant (B or eqQ/h) of the 3s23p54s[3/2]2 (3Po) and 3s23p54p[5/2]3 (3De) states of argon with large scale numerical complete active space self-consistent field and restricted active space self-consistent field calculations of the electric field gradient at the nucleus (q) using the LUCAS code, which is a finite-element based multiconfiguration Hartree-Fock program for atomic structure calculations.

Two-dimensional vibrational spectroscopy of the amide I band of crystalline acetanilide: Fermi resonance, conformational substates, or vibrational self-trapping?

NASA Astrophysics Data System (ADS)

Edler, J.; Hamm, P.

2003-08-01

Two-dimensional infrared (2D-IR) spectroscopy is applied to investigate acetanilide, a molecular crystal consisting of quasi-one-dimensional hydrogen bonded peptide units. The amide-I band exhibits a double peak structure, which has been attributed to different mechanisms including vibrational self-trapping, a Fermi resonance, or the existence of two conformational substates. The 2D-IR spectrum of crystalline acetanilide is compared with that of two different molecular systems: (i) benzoylchloride, which exhibits a strong symmetric Fermi resonance and (ii) N-methylacetamide dissolved in methanol which occurs in two spectroscopically distinguishable conformations. Both 2D-IR spectra differ significantly from that of crystalline acetanilide, proving that these two alternative mechanisms cannot account for the anomalous spectroscopy of crystalline acetanilide. On the other hand, vibrational self-trapping of the amide-I band can naturally explain the 2D-IR response.

Zeeman perturbed nuclear quadrupole spin echo envelope modulations for spin 3/2 nuclei in polycrystalline specimens

NASA Astrophysics Data System (ADS)

Ramachandran, R.; Narasimhan, P. T.

The results of theoretical and experimental studies of Zeeman-perturbed nuclear quadrupole spin echo envelope modulations (ZSEEM) for spin 3/2 nuclei in polycrystalline specimens are presented. The response of the Zeeman-perturbed spin ensemble to resonant two pulse excitations has been calculated using the density matrix formalism. The theoretical calculation assumes a parallel orientation of the external r.f. and static Zeeman fields and an arbitrary orientation of these fields to the principal axes system of the electric field gradient. A numerical powder averaging procedure has been adopted to simulate the response of the polycrystalline specimens. Using a coherent pulsed nuclear quadrupole resonance spectrometer the ZSEEM patterns of the 35Cl nuclei have been recorded in polycrystalline specimens of potassium chlorate, barium chlorate, mercuric chloride (two sites) and antimony trichloride (two sites) using the π/2-τ-π/2 sequence. The theoretical and experimental ZSEEM patterns have been compared. In the case of mercuric chloride, the experimental 35Cl ZSEEM patterns are found to be nearly identical for the two sites and correspond to a near-zero value of the asymmetry parameter, η, of the electric field gradient tensor. The difference in the η values for the two 35Cl sites (η ˜0·06 and η˜0·16) in antimony trichloride is clearly reflected in the experimental and theoretical ZSEEM patterns. The present study indicates the feasibility of evaluating η for spin 3/2 nuclei in polycrystalline specimens from ZSEEM investigations.

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

NASA Astrophysics Data System (ADS)

Belkić, Dževad; Belkić, Karen

2018-01-01

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

Characterization of carotenoids in soil bacteria and investigation of their photodegradation by UVA radiation via resonance Raman spectroscopy.

PubMed

Kumar B N, Vinay; Kampe, Bernd; Rösch, Petra; Popp, Jürgen

2015-07-07

A soil habitat consists of an enormous number of pigmented bacteria with the pigments mainly composed of diverse carotenoids. Most of the pigmented bacteria in the top layer of the soil are photoprotected from exposure to huge amounts of UVA radiation on a daily basis by these carotenoids. The photostability of these carotenoids depends heavily on the presence of specific features like a carbonyl group or an ionone ring system on its overall structure. Resonance Raman spectroscopy is one of the most sensitive and powerful techniques to detect and characterize these carotenoids and also monitor processes associated with them in their native system at a single cell resolution. However, most of the resonance Raman profiles of carotenoids have very minute differences, thereby making it extremely difficult to confirm if these differences are attributed to the presence of different carotenoids or if it is a consequence of their interaction with other cellular components. In this study, we devised a method to overcome this problem by monitoring also the photodegradation of the carotenoids in question by UVA radiation wherein a differential photodegradation response will confirm the presence of different carotenoids irrespective of the proximities in their resonance Raman profiles. Using this method, the detection and characterization of carotenoids in pure cultures of five species of pigmented coccoid soil bacteria is achieved. We also shed light on the influence of the structure of the carotenoid on its photodegradation which can be exploited for use in the characterization of carotenoids via resonance Raman spectroscopy.

Stand-off detection of explosives vapors by resonance-enhanced Raman spectroscopy

NASA Astrophysics Data System (ADS)

Johansson, Ida; Ceco, Ema; Ehlerding, Anneli; Östmark, Henric

2013-06-01

This paper describes a system for stand-off vapor detection based on Resonant Raman spectroscopy, RRS. The system is a step towards a RRS LIDAR (Light Detection And Ranging) system, capable of detecting vapors from explosives and explosives precursors at long distances. The current system was used to detect the vapor of nitromethane and mononitrotoluene outdoors in the open air, at a stand-off distance of 11-13 meters. Also, the signal dependence upon irradiation wavelength and sample concentration was studied in controlled laboratory conditions. A tunable Optical Parametric Oscillator pumped by an Nd:YAG laser, with a pulse length of 6 ns, was operated in the UV range of interest, 210-400 nm, illuminating the sample vapor. The backscattered Raman signal was collected by a telescope and a roundto- slit optical fiber was used to transmit collected light to the spectrometer with minimum losses. A gated intensified charge-coupled device (ICCD) registered the spectra. The nitromethane cross section was resonance enhanced more than a factor 30 700, when measured at 220 nm, compared to the 532 nm value. The results show that a decrease in concentration can have a positive effect on the sensitivity of the system, due to a decrease in absorption and selfabsorption in the sample.

Application of Nonlinear Elastic Resonance Spectroscopy For Damage Detection In Concrete: An Interesting Story

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

Byers, Loren W.; Ten Cate, James A.; Johnson, Paul A.

2012-06-28

Nonlinear resonance ultrasound spectroscopy experiments conducted on concrete cores, one chemically and mechanically damaged by alkali-silica reactivity, and one undamaged, show that this material displays highly nonlinear wave behavior, similar to many other damaged materials. They find that the damaged sample responds more nonlinearly, manifested by a larger resonant peak and modulus shift as a function of strain amplitude. The nonlinear response indicates that there is a hysteretic influence in the stress-strain equation of state. Further, as in some other materials, slow dynamics are present. The nonlinear response they observe in concrete is an extremely sensitive indicator of damage. Ultimately,more » nonlinear wave methods applied to concrete may be used to guide mixing, curing, or other production techniques, in order to develop materials with particular desired qualities such as enhanced strength or chemical resistance, and to be used for damage inspection.« less

Multinuclear nanoliter one-dimensional and two-dimensional NMR spectroscopy with a single non-resonant microcoil

NASA Astrophysics Data System (ADS)

Fratila, Raluca M.; Gomez, M. Victoria; Sýkora, Stanislav; Velders, Aldrik H.

2014-01-01

Nuclear magnetic resonance (NMR) spectroscopy is a powerful analytical technique, but its low sensitivity and highly sophisticated, costly, equipment severely constrain more widespread applications. Here we show that a non-resonant planar transceiver microcoil integrated in a microfluidic chip (detection volume 25 nl) can detect different nuclides in the full broad-band range of Larmor frequencies (at 9.4 T from 61 to 400 MHz). Routine one-dimensional (1D) and two-dimensional (2D), homo- and heteronuclear experiments can be carried out using the broad-band coil set-up. Noteworthy, heteronuclear 2D experiments can be performed in a straightforward manner on virtually any combination of nuclides (from classical 1H-13C to more exotic combinations like 19F-31P) both in coupled and decoupled mode. Importantly, the concept of a non-resonant system provides magnetic field-independent NMR probes; moreover, the small-volume alleviates problems related to field inhomogeneity, making the broad-band coil an attractive option for, for example, portable and table-top NMR systems.

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

(31)P cardiac magnetic resonance spectroscopy during leg exercise at 3 Tesla.

PubMed

Hudsmith, Lucy E; Tyler, Damian J; Emmanuel, Yaso; Petersen, Steffen E; Francis, Jane M; Watkins, Hugh; Clarke, Kieran; Robson, Matthew D; Neubauer, Stefan

2009-12-01

Investigation of phosphorus ((31)P) magnetic resonance spectroscopy under stress conditions provides a non-invasive tool to examine alterations in cardiac high-energy phosphate metabolism that may not be evident at rest. Our aim was to establish cardiac (31)P MR spectroscopy during leg exercise at 3T. The increased field strength should provide a higher signal to noise ratio than at lower field strengths. Furthermore, relatively high temporal resolution at a sufficiently fine spatial resolution should be feasible. (31)P MR spectra were obtained with a 3D acquisition weighted chemical shift imaging sequence in 20 healthy volunteers at rest, during dynamic physiological leg exercise and after recovery at 3T. Haemodynamic measurements were made throughout and the rate pressure product calculated. With exercise, the mean heart rate increased by 73%, achieving a mean increase in rate pressure product of 115%. The corrected PCr/ATP ratio for subjects at rest was 2.02 +/- 0.43, exercise 2.14 +/- 0.67 (P = 0.54 vs. rest) and at recovery 2.03 +/- 0.52 (P = 0.91 vs. rest, P = 0.62 vs. exercise). A cardiac (31)P MR spectroscopy physiological exercise-recovery protocol is feasible at 3T. There was no significant change in high-energy cardiac phosphate metabolite concentrations in healthy volunteers at rest, during physiological leg exercise or during recovery. When applied to patients with heart disease, this protocol should provide insights into physiological and pathological cardiac metabolism.

Comparison among T1-weighted magnetic resonance imaging, modified dixon method, and magnetic resonance spectroscopy in measuring bone marrow fat.

PubMed

Shen, Wei; Gong, Xiuqun; Weiss, Jessica; Jin, Ye

2013-01-01

An increasing number of studies are utilizing different magnetic resonance (MR) methods to quantify bone marrow fat due to its potential role in osteoporosis. Our aim is to compare the measurements of bone marrow fat among T1-weighted magnetic resonance imaging (MRI), modified Dixon method (also called fat fraction MRI (FFMRI)), and magnetic resonance spectroscopy (MRS). Contiguous MRI scans were acquired in 27 Caucasian postmenopausal women with a modified Dixon method (i.e., FFMRI). Bone marrow adipose tissue (BMAT) of T1-weighted MRI and bone marrow fat fraction of the L3 vertebra and femoral necks were quantified using SliceOmatic and Matlab. MRS was also acquired at the L3 vertebra. Correlation among the three MR methods measured bone marrow fat fraction and BMAT ranges from 0.78 to 0.88 (P < 0.001) in the L3 vertebra. Correlation between BMAT measured by T1-weighted MRI and bone marrow fat fraction measured by modified FFMRI is 0.86 (P < 0.001) in femoral necks. There are good correlations among T1-weighted MRI, FFMRI, and MRS for bone marrow fat quantification. The inhomogeneous distribution of bone marrow fat, the threshold segmentation of the T1-weighted MRI, and the ambiguity of the FFMRI may partially explain the difference among the three methods.

Comparison among T1-Weighted Magnetic Resonance Imaging, Modified Dixon Method, and Magnetic Resonance Spectroscopy in Measuring Bone Marrow Fat

PubMed Central

Shen, Wei; Gong, Xiuqun; Weiss, Jessica; Jin, Ye

2013-01-01

Introduction. An increasing number of studies are utilizing different magnetic resonance (MR) methods to quantify bone marrow fat due to its potential role in osteoporosis. Our aim is to compare the measurements of bone marrow fat among T1-weighted magnetic resonance imaging (MRI), modified Dixon method (also called fat fraction MRI (FFMRI)), and magnetic resonance spectroscopy (MRS). Methods. Contiguous MRI scans were acquired in 27 Caucasian postmenopausal women with a modified Dixon method (i.e., FFMRI). Bone marrow adipose tissue (BMAT) of T1-weighted MRI and bone marrow fat fraction of the L3 vertebra and femoral necks were quantified using SliceOmatic and Matlab. MRS was also acquired at the L3 vertebra. Results. Correlation among the three MR methods measured bone marrow fat fraction and BMAT ranges from 0.78 to 0.88 (P < 0.001) in the L3 vertebra. Correlation between BMAT measured by T1-weighted MRI and bone marrow fat fraction measured by modified FFMRI is 0.86 (P < 0.001) in femoral necks. Conclusion. There are good correlations among T1-weighted MRI, FFMRI, and MRS for bone marrow fat quantification. The inhomogeneous distribution of bone marrow fat, the threshold segmentation of the T1-weighted MRI, and the ambiguity of the FFMRI may partially explain the difference among the three methods. PMID:23606951

57Fe Mössbauer spectroscopy and electron paramagnetic resonance studies of human liver ferritin, Ferrum Lek and Maltofer®

NASA Astrophysics Data System (ADS)

Alenkina, I. V.; Oshtrakh, M. I.; Klencsár, Z.; Kuzmann, E.; Chukin, A. V.; Semionkin, V. A.

2014-09-01

A human liver ferritin, commercial Ferrum Lek and Maltofer® samples were studied using Mössbauer spectroscopy and electron paramagnetic resonance. Two Mössbauer spectrometers have been used: (i) a high velocity resolution (4096 channels) at 90 and 295 K, (ii) and a low velocity resolution (250 channels) at 20 and 40 K. It is shown that the three studied materials have different superparamagnetic features at various temperatures. This may be caused by different magnetic anisotropy energy barriers, sizes (volume), structures and compositions of the iron cores. The electron paramagnetic resonance spectra of the ferritin, Ferrum Lek and Maltofer® were decomposed into multiple spectral components demonstrating the presence of minor ferro- or ferrimagnetic phases along with revealing marked differences among the studied substances. Mössbauer spectroscopy provides evidences on several components in the measured spectra which could be related to different regions, layers, nanocrystallites, etc. in the iron cores that coincides with heterogeneous and multiphase models for the ferritin iron cores.

In Vivo Assessment of Neurotransmitters and Modulators with Magnetic Resonance Spectroscopy: Application to Schizophrenia

PubMed Central

Wijtenburg, S. Andrea; Yang, Shaolin; Fischer, Bernard A.; Rowland, Laura M.

2015-01-01

In vivo measurement of neurotransmitters and modulators is now feasible with advanced proton magnetic resonance spectroscopy (1H-MRS) techniques. This review provides a basic tutorial of MRS, describes the methods available to measure brain glutamate, glutamine, γ-aminobutyric acid, glutathione, N-acetylaspartylglutamate, glycine, and serine at magnetic field strengths of 3Tesla or higher, and summarizes the neurochemical findings in schizophrenia. Overall, 1H-MRS holds great promise for producing biomarkers that can serve as treatment targets, prediction of disease onset, or illness exacerbation in schizophrenia and other brain diseases. PMID:25614132

Information flow and protein dynamics: the interplay between nuclear magnetic resonance spectroscopy and molecular dynamics simulations

PubMed Central

Pastor, Nina; Amero, Carlos

2015-01-01

Proteins participate in information pathways in cells, both as links in the chain of signals, and as the ultimate effectors. Upon ligand binding, proteins undergo conformation and motion changes, which can be sensed by the following link in the chain of information. Nuclear magnetic resonance (NMR) spectroscopy and molecular dynamics (MD) simulations represent powerful tools for examining the time-dependent function of biological molecules. The recent advances in NMR and the availability of faster computers have opened the door to more detailed analyses of structure, dynamics, and interactions. Here we briefly describe the recent applications that allow NMR spectroscopy and MD simulations to offer unique insight into the basic motions that underlie information transfer within and between cells. PMID:25999971

Analytical Chemistry of 2,4,6-Trinitrotoluene

DTIC Science & Technology

1980-10-01

resonance absorption spectroscopy techniques involving NMR, electron spin resonance, and nuclear quadrupole resonance ( NQR ), were investigated for the...ref 135). The NQR was used for the determination of the chemical structure, crystalline states, and morphology of TNT (ref 136). The NMR was used...pp 898-902, (1970). ’ 136. R.A. Marino, D. Wade, and S.M. Klainer, "An NQR Study of the TNT Characteristics," US NTIS AD-A046729, p 68, (1977). 22

Optical Absorption Spectra of Hydrogenated Microcrystalline Silicon Films by Resonant Photothermal Bending Spectroscopy

NASA Astrophysics Data System (ADS)

Kunii, Toshie; Yoshida, Norimitsu; Hori, Yasuro; Nonomura, Shuichi

2006-05-01

A resonant photothermal bending spectroscopy (PBS) is demonstrated for the measurement of absorption coefficient spectra in hydrogenated microcrystalline silicon (μc-Si:H) and hydrogenated microcrystalline cubic silicon carbide (μc-3C-SiC:H) films. The resonant vibration technique utilized in PBS establishes the sensitivity as α d˜ 5× 10-5 in a vacuum measurement. Appling resonant PBS to μc-Si:H films, a new extra absorption coefficient αex spectrum is observed from 0.6 to 1.2 eV. The αex spectrum has a peak at ˜1.0 eV, and the localized states inducing the αex are located ˜0.35 eV below the conduction band edge of μc-Si:H. A possible explanation for the observed localized state is that an oxidation produces weak bonds at the grain boundaries and/or amorphous silicon tissues. In μc-3C-SiC:H film, an optical band-gap energy of ˜2.2 eV was demonstrated assuming an indirect optical transition. The temperature coefficient of the optical band-gap energy was ˜2.3× 10-4 eV K-1. The αex spectrum of μc-3C-SiC:H film is plateau-shaped and its magnitude is in accord with an increase in grain size.

Lifetime Measurements in Neutron-Rich Xe Isotopes — Evolution of Quadrupole Collectivity Beyond 132Sn

NASA Astrophysics Data System (ADS)

Ilieva, S.; Bönig, S.; Hartig, A.-L.; Henrich, C.; Ignatov, A.; Kröll, Th.; Thürauf, M.; Jolie, J.; Régis, J.-M.; Saed-Samii, N.; Blanc, A.; de France, G.; Jentschel, M.; Köster, U.; Mutti, P.; Simpson, G. S.; Soldner, T.; Urban, W.; Mǎrginean, N.; Ur, C. A.; Mach, H.; Fraile, L. M.; Paziy, V.; Regan, P. H.; Bruce, A. M.; Lalkovski, S.; Korten, W.

Picosecond lifetimes of excited states in neutron-rich Xe isotopes were measured at the Institut Laue-Langevin via γ-ray spectroscopy of fission fragments from neutron-induced fission of 235U and 241Pu targets. The data collected with the recently installed fast timing array FATIMA in combination with the EXOGAM Ge array were analysed using the new generalized centroid difference method. Our aim is to study the quadrupole and octupole collectivity, arising in the mass region beyond the doubly magic 132Sn, by means of transition probabilities. These can be calculated from the directly measured lifetimes.

Measurements of vitamin B12 in human blood serum using resonance Raman spectroscopy

NASA Astrophysics Data System (ADS)

Tsiminis, G.; Schartner, E. P.; Brooks, J. L.; Hutchinson, M. R.

2016-12-01

Vitamin B12 (cobalamin and its derivatives) deficiency has been identified as a potential modifiable risk factor for dementia and Alzheimer's disease. Chronic deficiency of vitamin B12 has been significantly associated with an increased risk of cognitive decline. An effective and efficient method for measuring vitamin B12 concentration in human blood would enable ongoing tracking and assessment of this potential modifiable risk factor. In this work we present an optical sensor based on resonance Raman spectroscopy for rapid measurements of vitamin B12 in human blood serum. The measurement takes less than a minute and requires minimum preparation (centrifuging) of the collected blood samples.

Magnetic resonance spectroscopy-guided transperineal prostate biopsy and brachytherapy for recurrent prostate cancer.

PubMed

Barnes, Agnieszka Szot; Haker, Steven J; Mulkern, Robert V; So, Minna; D'Amico, Anthony V; Tempany, Clare M

2005-12-01

Brachytherapy targeted to the peripheral zone with magnetic resonance imaging (MRI) guidance is a prostate cancer treatment option with potentially fewer complications than other treatments. Follow-up MRI when failure is suspected is, however, difficult because of radiation-induced changes. Furthermore, MR spectroscopy (MRS) is compromised by susceptibility artifacts from radioactive seeds in the peripheral zone. We report a case in which combined MRI/MRS was useful for the detection of prostate cancer in the transitional zone in patients previously treated with MR-guided brachytherapy. We propose that MRI/MRS can help detect recurrent prostate cancer, guide prostate biopsy, and help manage salvage treatment decisions.

Differentially pumped dual linear quadrupole ion trap mass spectrometer

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

Owen, Benjamin C.; Kenttamaa, Hilkka I.

The present disclosure provides a new tandem mass spectrometer and methods of using the same for analyzing charged particles. The differentially pumped dual linear quadrupole ion trap mass spectrometer of the present disclose includes a combination of two linear quadrupole (LQIT) mass spectrometers with differentially pumped vacuum chambers.

Ellipsoidal all-dielectric Fano resonant core-shell metamaterials

NASA Astrophysics Data System (ADS)

Reena, Reena; Kalra, Yogita; Kumar, Ajeet

2018-06-01

In this paper, ellipsoidal core (Si) and shell (SiO2) metamaterial has been proposed for highly directional properties. At the wavelength of magnetic resonance, Fano dip occurs in the backward scattering cross section and forward scattering enhancement takes place at the same wavelength so that there is an increment in the directivity. Effect on the directivity by changing the length of ellipsoidal nanoparticle along semi-axes has been analyzed. Two Fano resonances have been observed by decreasing the length of the nanoparticle along the semi-axis having electric polarization, where first and second Fano resonances are attributed to the dipole and quadrupole moments, respectively. These Fano resonant wavelengths in ellipsoidal nanoparticle exhibit higher directivity than the Kerker's type scattering or forward scattering shown by symmetrical structures like sphere. So, this core-shell metamaterial can act as an efficient directional nanoantenna.

Excitation of ultrasharp trapped-mode resonances in mirror-symmetric metamaterials

NASA Astrophysics Data System (ADS)

Yang, Shengyan; Liu, Zhe; Xia, Xiaoxiang; E, Yiwen; Tang, Chengchun; Wang, Yujin; Li, Junjie; Wang, Li; Gu, Changzhi

2016-06-01

We experimentally demonstrate a metamaterial structure composed of two mirror-symmetric joint split ring resonators (JSRRs) that support extremely sharp trapped-mode resonance with a large modulation depth in the terahertz region. Contrary to the regular mirror-arranged SRR arrays in which both the subradiant inductive-capacitive (LC) resonance and quadrupole-mode resonance can be excited, our designed structure features a metallic microstrip bridging the adjacent SRRs, which leads to the emergence of an otherwise inaccessible ultrahigh-quality-factor resonance. The ultrasharp resonance occurs near the Wood-Rayleigh anomaly frequency, and the underlying mechanism can be attributed to the strong coupling between the in-plane propagating collective lattice surface mode originating from the array periodicity and localized surface plasmon resonance in mirror-symmetric coupled JSRRs, which dramatically reduces radiative damping. The ultrasharp resonance shows great potential for multifunctional applications such as plasmonic switching, low-power nonlinear processing, and chemical and biological sensing.

Miniature micromachined quadrupole mass spectrometer array and method of making the same

NASA Technical Reports Server (NTRS)

Chutjian, Ara (Inventor); Brennen, Reid A. (Inventor); Hecht, Michael (Inventor); Wiberg, Dean (Inventor); Orient, Otto (Inventor)

2001-01-01

The present invention provides a quadrupole mass spectrometer and an ion filter for use in the quadrupole mass spectrometer. The ion filter includes a thin patterned layer including a two-dimensional array of poles forming one or more quadrupoles. The patterned layer design permits the use of very short poles and with a very dense spacing of the poles, so that the ion filter may be made very small. Also provided is a method for making the ion filter and the quadrupole mass spectrometer. The method involves forming the patterned layer of the ion filter in such a way that as the poles of the patterned layer are formed, they have the relative positioning and alignment for use in a final quadrupole mass spectrometer device.

Miniature micromachined quadrupole mass spectrometer array and method of making the same

NASA Technical Reports Server (NTRS)

Hecht, Michael (Inventor); Wiberg, Dean (Inventor); Orient, Otto (Inventor); Brennen, Reid A. (Inventor); Chutjian, Ara (Inventor)

2001-01-01

The present invention provides a quadrupole mass spectrometer and an ion filter for use in the quadrupole mass spectrometer. The ion filter includes a thin patterned layer including a two-dimensional array of poles forming one or more quadrupoles. The patterned layer design permits the use of very short poles and with a very dense spacing of the poles, so that the ion filter may be made very small. Also provided is a method for making the ion filter and the quadrupole mass spectrometer. The method involves forming the patterned layer of the ion filter in such a way that as the poles of the patterned layer are formed, they have the relative positioning and aligrnent for use in a final quadrupole mass spectrometer device.

Miniature micromachined quadrupole mass spectrometer array and method of making the same

NASA Technical Reports Server (NTRS)

Orient, Otto (Inventor); Wiberg, Dean (Inventor); Brennen, Reid A. (Inventor); Hecht, Michael (Inventor); Chutjian, Ara (Inventor)

2000-01-01

The present invention provides a quadrupole mass spectrometer and an ion filter for use in the quadrupole mass spectrometer. The ion filter includes a thin patterned layer including a two-dimensional array of poles forming one or more quadrupoles. The patterned layer design permits the use of very short poles and with a very dense spacing of the poles, so that the ion filter may be made very small. Also provided is a method for making the ion filter and the quadrupole mass spectrometer. The method involves forming the patterned layer of the ion filter in such a way that as the poles of the patterned layer are formed, they have the relative positioning and alignment for use in a final quadrupole mass spectrometer device.

The quadrupole ionosphere

NASA Technical Reports Server (NTRS)

Rishbeth, H.

1986-01-01

The principal features that might exist in the terrestrial paleoionosphere, if the geomagnetic field were to assume a quadrupole form during a polarity reversal are discussed. Complicated phenomena would be expected to occur at magnetic equators and magnetospherically-driven plasma convection might occur at latitudes where the magnetic field is steeply inclined. The influence of magnetic field strength on ionospheric structure is considered in general terms.

Multi-Pass Quadrupole Mass Analyzer

NASA Technical Reports Server (NTRS)

Prestage, John D.

2013-01-01

Analysis of the composition of planetary atmospheres is one of the most important and fundamental measurements in planetary robotic exploration. Quadrupole mass analyzers (QMAs) are the primary tool used to execute these investigations, but reductions in size of these instruments has sacrificed mass resolving power so that the best present-day QMA devices are still large, expensive, and do not deliver performance of laboratory instruments. An ultra-high-resolution QMA was developed to resolve N2 +/CO+ by trapping ions in a linear trap quadrupole filter. Because N2 and CO are resolved, gas chromatography columns used to separate species before analysis are eliminated, greatly simplifying gas analysis instrumentation. For highest performance, the ion trap mode is used. High-resolution (or narrow-band) mass selection is carried out in the central region, but near the DC electrodes at each end, RF/DC field settings are adjusted to allow broadband ion passage. This is to prevent ion loss during ion reflection at each end. Ions are created inside the trap so that low-energy particles are selected by low-voltage settings on the end electrodes. This is beneficial to good mass resolution since low-energy particles traverse many cycles of the RF filtering fields. Through Monte Carlo simulations, it is shown that ions are reflected at each end many tens of times, each time being sent back through the central section of the quadrupole where ultrahigh mass filtering is carried out. An analyzer was produced with electrical length orders of magnitude longer than its physical length. Since the selector fields are sized as in conventional devices, the loss of sensitivity inherent in miniaturizing quadrupole instruments is avoided. The no-loss, multi-pass QMA architecture will improve mass resolution of planetary QMA instruments while reducing demands on the RF electronics for high-voltage/high-frequency production since ion transit time is no longer limited to a single pass. The

A portable blood plasma clot micro-elastometry device based on resonant acoustic spectroscopy

NASA Astrophysics Data System (ADS)

Krebs, C. R.; Li, Ling; Wolberg, Alisa S.; Oldenburg, Amy L.

2015-07-01

Abnormal blood clot stiffness is an important indicator of coagulation disorders arising from a variety of cardiovascular diseases and drug treatments. Here, we present a portable instrument for elastometry of microliter volume blood samples based upon the principle of resonant acoustic spectroscopy, where a sample of well-defined dimensions exhibits a fundamental longitudinal resonance mode proportional to the square root of the Young's modulus. In contrast to commercial thromboelastography, the resonant acoustic method offers improved repeatability and accuracy due to the high signal-to-noise ratio of the resonant vibration. We review the measurement principles and the design of a magnetically actuated microbead force transducer applying between 23 pN and 6.7 nN, providing a wide dynamic range of elastic moduli (3 Pa-27 kPa) appropriate for measurement of clot elastic modulus (CEM). An automated and portable device, the CEMport, is introduced and implemented using a 2 nm resolution displacement sensor with demonstrated accuracy and precision of 3% and 2%, respectively, of CEM in biogels. Importantly, the small strains (<0.13%) and low strain rates (<1/s) employed by the CEMport maintain a linear stress-to-strain relationship which provides a perturbative measurement of the Young's modulus. Measurements of blood plasma CEM versus heparin concentration show that CEMport is sensitive to heparin levels below 0.050 U/ml, which suggests future applications in sensing heparin levels of post-surgical cardiopulmonary bypass patients. The portability, high accuracy, and high precision of this device enable new clinical and animal studies for associating CEM with blood coagulation disorders, potentially leading to improved diagnostics and therapeutic monitoring.

A portable blood plasma clot micro-elastometry device based on resonant acoustic spectroscopy

PubMed Central

Krebs, C. R.; Li, Ling; Wolberg, Alisa S.; Oldenburg, Amy L.

2015-01-01

Abnormal blood clot stiffness is an important indicator of coagulation disorders arising from a variety of cardiovascular diseases and drug treatments. Here, we present a portable instrument for elastometry of microliter volume blood samples based upon the principle of resonant acoustic spectroscopy, where a sample of well-defined dimensions exhibits a fundamental longitudinal resonance mode proportional to the square root of the Young’s modulus. In contrast to commercial thromboelastography, the resonant acoustic method offers improved repeatability and accuracy due to the high signal-to-noise ratio of the resonant vibration. We review the measurement principles and the design of a magnetically actuated microbead force transducer applying between 23 pN and 6.7 nN, providing a wide dynamic range of elastic moduli (3 Pa–27 kPa) appropriate for measurement of clot elastic modulus (CEM). An automated and portable device, the CEMport, is introduced and implemented using a 2 nm resolution displacement sensor with demonstrated accuracy and precision of 3% and 2%, respectively, of CEM in biogels. Importantly, the small strains (<0.13%) and low strain rates (<1/s) employed by the CEMport maintain a linear stress-to-strain relationship which provides a perturbative measurement of the Young’s modulus. Measurements of blood plasma CEM versus heparin concentration show that CEMport is sensitive to heparin levels below 0.050 U/ml, which suggests future applications in sensing heparin levels of post-surgical cardiopulmonary bypass patients. The portability, high accuracy, and high precision of this device enable new clinical and animal studies for associating CEM with blood coagulation disorders, potentially leading to improved diagnostics and therapeutic monitoring. PMID:26233406

A portable blood plasma clot micro-elastometry device based on resonant acoustic spectroscopy.

PubMed

Krebs, C R; Li, Ling; Wolberg, Alisa S; Oldenburg, Amy L

2015-07-01

Abnormal blood clot stiffness is an important indicator of coagulation disorders arising from a variety of cardiovascular diseases and drug treatments. Here, we present a portable instrument for elastometry of microliter volume blood samples based upon the principle of resonant acoustic spectroscopy, where a sample of well-defined dimensions exhibits a fundamental longitudinal resonance mode proportional to the square root of the Young's modulus. In contrast to commercial thromboelastography, the resonant acoustic method offers improved repeatability and accuracy due to the high signal-to-noise ratio of the resonant vibration. We review the measurement principles and the design of a magnetically actuated microbead force transducer applying between 23 pN and 6.7 nN, providing a wide dynamic range of elastic moduli (3 Pa-27 kPa) appropriate for measurement of clot elastic modulus (CEM). An automated and portable device, the CEMport, is introduced and implemented using a 2 nm resolution displacement sensor with demonstrated accuracy and precision of 3% and 2%, respectively, of CEM in biogels. Importantly, the small strains (<0.13%) and low strain rates (<1/s) employed by the CEMport maintain a linear stress-to-strain relationship which provides a perturbative measurement of the Young's modulus. Measurements of blood plasma CEM versus heparin concentration show that CEMport is sensitive to heparin levels below 0.050 U/ml, which suggests future applications in sensing heparin levels of post-surgical cardiopulmonary bypass patients. The portability, high accuracy, and high precision of this device enable new clinical and animal studies for associating CEM with blood coagulation disorders, potentially leading to improved diagnostics and therapeutic monitoring.

Resonance Raman Spectroscopy of Extreme Nanowires and Other 1D Systems

PubMed Central

Smith, David C.; Spencer, Joseph H.; Sloan, Jeremy; McDonnell, Liam P.; Trewhitt, Harrison; Kashtiban, Reza J.; Faulques, Eric

2016-01-01

This paper briefly describes how nanowires with diameters corresponding to 1 to 5 atoms can be produced by melting a range of inorganic solids in the presence of carbon nanotubes. These nanowires are extreme in the sense that they are the limit of miniaturization of nanowires and their behavior is not always a simple extrapolation of the behavior of larger nanowires as their diameter decreases. The paper then describes the methods required to obtain Raman spectra from extreme nanowires and the fact that due to the van Hove singularities that 1D systems exhibit in their optical density of states, that determining the correct choice of photon excitation energy is critical. It describes the techniques required to determine the photon energy dependence of the resonances observed in Raman spectroscopy of 1D systems and in particular how to obtain measurements of Raman cross-sections with better than 8% noise and measure the variation in the resonance as a function of sample temperature. The paper describes the importance of ensuring that the Raman scattering is linearly proportional to the intensity of the laser excitation intensity. It also describes how to use the polarization dependence of the Raman scattering to separate Raman scattering of the encapsulated 1D systems from those of other extraneous components in any sample. PMID:27168195

Temperature determination of resonantly excited plasmonic branched gold nanoparticles by X-ray absorption spectroscopy.

PubMed

Van de Broek, Bieke; Grandjean, Didier; Trekker, Jesse; Ye, Jian; Verstreken, Kris; Maes, Guido; Borghs, Gustaaf; Nikitenko, Sergey; Lagae, Liesbet; Bartic, Carmen; Temst, Kristiaan; Van Bael, Margriet J

2011-09-05

The fields of bioscience and nanomedicine demand precise thermometry for nanoparticle heat characterization down to the nanoscale regime. Since current methods often use indirect and less accurate techniques to determine the nanoparticle temperature, there is a pressing need for a direct and reliable element-specific method. In-situ extended X-ray absorption fine structure (EXAFS) spectroscopy is used to determine the thermo-optical properties of plasmonic branched gold nanoparticles upon resonant laser illumination. With EXAFS, the direct determination of the nanoparticle temperature increase upon laser illumination is possible via the thermal influence on the gold lattice parameters. More specifically, using the change of the Debye-Waller term representing the lattice disorder, the temperature increase is selectively measured within the plasmonic branched nanoparticles upon resonant laser illumination. In addition, the signal intensity shows that the nanoparticle concentration in the beam more than doubles during laser illumination, thereby demonstrating that photothermal heating is a dynamic process. A comparable temperature increase is measured in the nanoparticle suspension using a thermocouple. This good correspondence between the temperature at the level of the nanoparticle and at the level of the suspension points to an efficient heat transfer between the nanoparticle and the surrounding medium, thus confirming the potential of branched gold nanoparticles for hyperthermia applications. This work demonstrates that X-ray absorption spectroscopy-based nanothermometry could be a valuable tool in the fast-growing number of applications of plasmonic nanoparticles, particularly in life sciences and medicine. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Proton magnetic resonance spectroscopy in focal cortical dysplasia at 3T.

PubMed

Tschampa, Henriette J; Urbach, Horst; Träber, Frank; Sprinkart, Alois M; Greschus, Susanne; Malter, Michael P; Surges, Rainer; Gieseke, Jürgen; Block, Wolfgang

2015-11-01

Focal cortical dysplasia (FCD) type II is a frequent cause of medically intractable epilepsy. On conventional MRI diagnosis may be difficult. The purpose of our study was to assess the metabolic characteristics of MRI-typical or neuropathologically confirmed FCD II lesions at 3T. In a prospective study, 13 patients with drug-resistant epilepsy and MRI diagnosis of FCD II (seven neuropathologically confirmed) were investigated by single-volume proton magnetic resonance spectroscopy ((1)H MRS). We performed an intra-individual comparison placing spectroscopic volumes of interest in the lesion and in the apparently normal contralateral hemisphere. Spectroscopic results were correlated with clinical data. Matched pair analysis revealed a significant increase in absolute choline (Cho) concentration in the lesion volume (+32%, p=0.015) compared to the control volume. This increase was associated with a significant decrease in N-acetyl-aspartate (NAA) concentration (-13%; p=0.008). Mean myo-inositol (Ins) levels were distinctly (+36%) but not significantly (p=0.051) elevated. Lesional creatine (Cr) concentration correlated significantly with the frequency of seizures (Spearman-Rho r=0.898; p=0.002), while concentrations of NAA, Cho and Ins did not correlate with clinical or imaging parameters. MR spectroscopy revealed a characteristic metabolic pattern in FCD II lesions that helps to distinguish normal from epileptogenic tissue. Copyright © 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

A compensating point defect in carbon-doped GaN substrates studied with electron paramagnetic resonance spectroscopy

NASA Astrophysics Data System (ADS)

Willoughby, W. R.; Zvanut, M. E.; Paudel, Subash; Iwinska, M.; Sochacki, T.; Bockowski, M.

2018-04-01

Electron paramagnetic resonance (EPR) spectroscopy was used to investigate a type of point defect present in 1019 cm-3 carbon-doped GaN substrates grown by hydride vapor phase epitaxy. A broad, isotropic resonance at g ˜ 1.987 was observed at 3.5 K, and the EPR intensity increased with illumination at energies greater than 2.75 eV and decreased with photon energies greater than 0.95 eV. The latter is consistent with a deep level of 0.95 eV above the valence band maximum and implies that the associated defect likely participates in donor compensation. The ionization energy for this defect is close to the predicted value for the (-/0) transition level of CN and transition levels associated with Ga vacancies such as VGa and VGa-ON-2H.

Mass resolution of linear quadrupole ion traps with round rods.

PubMed

Douglas, D J; Konenkov, N V

2014-11-15

Auxiliary dipole excitation is widely used to eject ions from linear radio-frequency quadrupole ion traps for mass analysis. Linear quadrupoles are often constructed with round rod electrodes. The higher multipoles introduced to the electric potential by round rods might be expected to change the ion ejection process. We have therefore investigated the optimum ratio of rod radius, r, to field radius, r0, for excitation and ejection of ions. Trajectory calculations are used to determine the excitation contour, S(q), the fraction of ions ejected when trapped at q values close to the ejection (or excitation) q. Initial conditions are randomly selected from Gaussian distributions of the x and y coordinates and a thermal distribution of velocities. The N = 6 (12 pole) and N = 10 (20 pole) multipoles are added to the quadrupole potential. Peak shapes and resolution were calculated for ratios r/r0 from 1.09 to 1.20 with an excitation time of 1000 cycles of the trapping radio-frequency. Ratios r/r0 in the range 1.140 to 1.160 give the highest resolution and peaks with little tailing. Ratios outside this range give lower resolution and peaks with tails on either the low-mass side or the high-mass side of the peaks. This contrasts with the optimum ratio of 1.126-1.130 for a quadrupole mass filter operated conventionally at the tip of the first stability region. With the optimum geometry the resolution is 2.7 times greater than with an ideal quadrupole field. Adding only a 2.0% hexapole field to a quadrupole field increases the resolution by a factor of 1.6 compared with an ideal quadrupole field. Addition of a 2.0% octopole lowers resolution and degrades peak shape. With the optimum value of r/r0 , the resolution increases with the ejection time (measured in cycles of the trapping rf, n) approximately as R0.5 = 6.64n, in contrast to a pure quadrupole field where R0.5 = 1.94n. Adding weak nonlinear fields to a quadrupole field can improve the resolution with

High field electron paramagnetic resonance spectroscopy under ultrahigh vacuum conditions—A multipurpose machine to study paramagnetic species on well defined single crystal surfaces

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

Rocker, J.; Cornu, D.; Kieseritzky, E.

2014-08-01

A new ultrahigh vacuum (UHV) electron paramagnetic resonance (EPR) spectrometer operating at 94 GHz to investigate paramagnetic centers on single crystal surfaces is described. It is particularly designed to study paramagnetic centers on well-defined model catalysts using epitaxial thin oxide films grown on metal single crystals. The EPR setup is based on a commercial Bruker E600 spectrometer, which is adapted to ultrahigh vacuum conditions using a home made Fabry Perot resonator. The key idea of the resonator is to use the planar metal single crystal required to grow the single crystalline oxide films as one of the mirrors of themore » resonator. EPR spectroscopy is solely sensitive to paramagnetic species, which are typically minority species in such a system. Hence, additional experimental characterization tools are required to allow for a comprehensive investigation of the surface. The apparatus includes a preparation chamber hosting equipment, which is required to prepare supported model catalysts. In addition, surface characterization tools such as low energy electron diffraction (LEED)/Auger spectroscopy, temperature programmed desorption (TPD), and infrared reflection absorption spectroscopy (IRAS) are available to characterize the surfaces. A second chamber used to perform EPR spectroscopy at 94 GHz has a room temperature scanning tunneling microscope attached to it, which allows for real space structural characterization. The heart of the UHV adaptation of the EPR experiment is the sealing of the Fabry-Perot resonator against atmosphere. To this end it is possible to use a thin sapphire window glued to the backside of the coupling orifice of the Fabry Perot resonator. With the help of a variety of stabilization measures reducing vibrations as well as thermal drift it is possible to accumulate data for a time span, which is for low temperature measurements only limited by the amount of liquid helium. Test measurements show that the system can detect

Determination of elastic properties of polycrystalline U 3Si 2 using resonant ultrasound spectroscopy

DOE PAGES

Carvajal-Nunez, Ursula; Saleh, Tarik A.; White, Joshua Taylor; ...

2017-11-10

For this research, the elastic properties of U 3Si 2 at room temperature have been measured via resonant ultrasound spectroscopy. Results show that the average value of Young's and the bulk modulus for U 3Si 2 are 130.4±0.5 and 68.3±0.5 GPa, respectively. Further, a numerical model to assess thermal stress in an operating fuel is evaluated. Lastly, the thermal stress evolved in U 3Si 2 is compared to UO 2 to facilitate an estimation of the probability of crack formation in U 3Si 2 under representative light water reactor operating conditions.

Determination of elastic properties of polycrystalline U 3Si 2 using resonant ultrasound spectroscopy

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

Carvajal-Nunez, Ursula; Saleh, Tarik A.; White, Joshua Taylor

For this research, the elastic properties of U 3Si 2 at room temperature have been measured via resonant ultrasound spectroscopy. Results show that the average value of Young's and the bulk modulus for U 3Si 2 are 130.4±0.5 and 68.3±0.5 GPa, respectively. Further, a numerical model to assess thermal stress in an operating fuel is evaluated. Lastly, the thermal stress evolved in U 3Si 2 is compared to UO 2 to facilitate an estimation of the probability of crack formation in U 3Si 2 under representative light water reactor operating conditions.

Mid-infrared wavelength- and frequency-modulation spectroscopy with a pump-modulated singly-resonant optical parametric oscillator

NASA Astrophysics Data System (ADS)

Lindsay, I. D.; Groß, P.; Lee, C. J.; Adhimoolam, B.; Boller, K.-J.

2006-12-01

We describe the implementation of the wavelength- and frequency-modulation spectroscopy techniques using a singly-resonant optical parametric oscillator (OPO) pumped by a fiber-amplified diode laser. Frequency modulation of the diode laser was transferred to the OPO’s mid-infrared idler output, avoiding the need for external modulation devices. This approach thus provides a means of implementing these important techniques with powerful, widely tunable, mid-infrared sources while retaining the simple, flexible modulation properties of diode lasers.

Miniature micromachined quadrupole mass spectrometer array and method of making the same

NASA Technical Reports Server (NTRS)

Fuerstenau, Stephen D. (Inventor); Yee, Karl Y. (Inventor); Chutjian, Ara (Inventor); Orient, Otto J. (Inventor); Rice, John T. (Inventor)

2002-01-01

The present invention provides a quadrupole mass spectrometer and an ion filter, or pole array, for use in the quadrupole mass spectrometer. The ion filter includes a thin patterned layer including a two-dimensional array of poles forming one or more quadrupoles. The patterned layer design permits the use of very short poles and with a very dense spacing of the poles, so that the ion filter may be made very small. Also provided is a method for making the ion filter and the quadrupole mass spectrometer. The method involves forming the patterned layer of the ion filter in such a way that as the poles of the patterned layer are formed, they have the relative positioning and alignment for use in a final quadrupole mass spectrometer device.

Miniature micromachined quadrupole mass spectrometer array and method of making the same

NASA Technical Reports Server (NTRS)

Chutjian, Ara (Inventor); Rice, John T. (Inventor); Fuerstenau, Stephen D. (Inventor); Orient, Otto J. (Inventor); Yee, Karl Y. (Inventor)

2000-01-01

The present invention provides a quadrupole mass spectrometer and an ion filter, or pole array, for use in the quadrupole mass spectrometer. The ion filter includes a thin patterned layer including a two-dimensional array of poles forming one or more quadrupoles. The patterned layer design permits the use of very short poles and with a very dense spacing of the poles, so that the ion filter may be made very small. Also provided is a method for making the ion filter and the quadrupole mass spectrometer. The method involves forming the patterned layer of the ion filter in such a way that as the poles of the patterned layer are formed, they have the relative positioning and alignment for use in a final quadrupole mass spectrometer device.

Miniature micromachined quadrupole mass spectrometer array and method of making the same

NASA Technical Reports Server (NTRS)

Yee, Karl Y. (Inventor); Fuerstenau, Stephen D. (Inventor); Orient, Otto J. (Inventor); Rice, John T. (Inventor); Chutjian, Ara (Inventor)

2001-01-01

The present invention provides a quadrupole mass spectrometer and an ion filter, or pole array, for use in the quadrupole mass spectrometer. The ion filter includes a thin patterned layer including a two-dimensional array of poles forming one or more quadrupoles. The patterned layer design permits the use of very short poles and with a very dense spacing of the poles, so that the ion filter may be made very small. Also provided is a method for making the ion filter and the quadrupole mass spectrometer. The method involves forming the patterned layer of the ion filter in such a way that as the poles of the patterned layer are formed, they have the relative positioning and alignment for use in a final quadrupole mass spectrometer device.

Magnetic resonance spectroscopy of the canine brain at 3.0 T and 7.0 T.

PubMed

Martin-Vaquero, Paula; da Costa, Ronaldo C; Echandi, Rita L; Sammet, Christina L; Knopp, Michael V; Sammet, Steffen

2012-08-01

The purpose of this study was to evaluate the feasibility of proton magnetic resonance spectroscopy (1H MRS) to study the concentration of metabolites in the brain of dogs at 3.0 and 7.0 T. Four healthy male beagles were scanned using 3.0 T and 7.0 T human magnetic resonance imaging (MRI) units. The results obtained showed that all dogs had excellent quality spectra for a small (1 cm3) and large (8 cm3) voxel at 3.0 T, whereas only 2 dogs had high quality spectra at 7.0 T due to insufficient water suppression. 1H MRS at 3.0 T appears to be a reliable method to study metabolite concentrations in the canine brain. The development of more advanced water suppression techniques is necessary to improve the results at 7.0 T. Copyright © 2011 Elsevier Ltd. All rights reserved.

Resonant ultrasound spectroscopy and non-destructive testing

NASA Astrophysics Data System (ADS)

Migliori, A.; Darling, T. W.

The use of mechanical resonances to test properties of materials is perhaps older than the industrial revolution. Early documented cases of British railroad engineers tapping the wheels of a train and using the sound to detect cracks perhaps mark the first real use of resonances to test the integrity of high-performance alloys. Attempts were made in the following years to understand the resonances of solids mathematically, based on the shape and composition. But Nobel Laureate Lord Rayleigh best summarized the state of affairs in 1894, stating 'the problem has, for the most part, resisted attack'. More recently, modern computers and electronics have enabled Anderson and co-workers with their work on minerals, and our work at Los Alamos on new materials and manufactured components to advance the use of resonances to a precision non-destructive testing tool that makes anisotropic modulus measurements, defect detection and geometry error detection routine. The result is that resonances can achieve the highest absolute accuracy for any dynamic modulus measurement technique, can be used on the smallest samples, and can also enable detection of errors in certain classes of precision manufactured components faster and more accurately than any other technique.

Resonance Raman spectroscopy and the preterm infant carotenoid status.

PubMed

Chan, Gary M; Chan, Melissa M; Gellermann, Werner; Ermakov, Igor; Ermakova, Maia; Bhosale, Prakash; Bernstein, Paul; Rau, Carrie

2013-05-01

The aim of the study was to validate the noninvasive resonance Raman spectroscopy (RRS) method in infants in comparison with the high-performance liquid chromatography (HPLC) method, and to evaluate the carotenoid status in preterm infants fed with mother's milk or formula. In the first phase of the study, resonance Raman measurements were made on male term infants' skin and correlated with tissue harvested at the time of circumcision. Each baby's foreskin was weighed, enzymatically digested, and the total carotenoids were extracted and quantitated by the HPLC. Next, to evaluate the carotenoid status of preterm infants (BW <1500 g), the skin and serum carotenoids in infants fed with either human milk or preterm formula were studied from the start of feedings and every 2 weeks until hospital discharge. Skin carotenoids were measured by RRS and the serum total carotenoids by HPLC. Foreskin carotenoid levels measured by RRS correlated with HPLC measurements of total serum carotenoids (R = 0.52, P < 0.01, n = 16). Forty preterm infants were studied for their carotenoid status. Thirty-two infants were fed mother's milk, whereas 8 were fed a preterm infant formula that was not enriched with carotenoids. The gestation and birth weight of the 2 feeding groups were similar. The infants fed human milk had a higher serum total carotenoid concentration and skin Raman counts than formula-fed infants. The skin Raman counts and total serum carotenoid correlated (R = 0.44, P = 0.01). The human milk-fed infants' serum total carotenoid concentrations and Raman values did not change during the study period; however, the formula-fed group's total serum and skin carotenoid decreased significantly during the study. RRS of infant's skin reliably assesses total carotenoid status noninvasively. Human milk-fed preterm infants have higher serum and skin carotenoids than formula-fed infants suggesting that formula-fed infants may benefit from carotenoid supplementation.

Magnetic Resonance Spectroscopy for Evaluating the Effect of Pulsed Electromagnetic Fields on Marrow Adiposity in Postmenopausal Women With Osteopenia.

PubMed

Li, Shaojun; Jiang, Hongning; Wang, Bo; Gu, Mingjun; Bi, Xia; Yin, Ying; Wang, Yu

2018-06-12

Pulsed electromagnetic fields (PEMFs) could promote osteogenic differentiation and suppress adipogenic differentiation in bone mesenchymal stem cells ex vivo. However, data on the effect of PEMF on marrow adiposity in humans remain elusive. We aimed to determine the in vivo effect of PEMF on marrow adiposity in postmenopausal women using magnetic resonance spectroscopy. Sixty-one postmenopausal women with osteopenia, aged 53 to 85 years, were randomly assigned to receive either PEMF treatment or placebo. The session was performed 3 times per week for 6 months. All women received adequate dietary calcium and vitamin D. Bone mineral density (BMD) by dual-energy x-ray absorptiometry, vertebral marrow fat content by magnetic resonance spectroscopy, and serum biomarkers were evaluated before and after 6 months of treatment. A total of 27 (87.1%) and 25 (83.3%) women completed the treatment schedule in the PEMF and placebo groups, respectively. After the 6-month treatment, lumbar spine and hip BMD increased by 1.46% to 2.04%, serum bone-specific alkaline phosphatase increased by 3.23%, and C-terminal telopeptides of type 1 collagen decreased by 9.12% in the PEMF group (P < 0.05), whereas the mean percentage changes in BMD and serum biomarkers were not significant in the placebo group. Pulsed electromagnetic field treatment significantly reduced marrow fat fraction by 4.81%. The treatment difference between the 2 groups was -4.43% (95% confidence interval, -3.70% to -5.65%; P = 0.009). Pulsed electromagnetic field is an effective physiotherapy in postmenopausal women, and this effect may, at least in part, regulate the amount of fat within the bone marrow. Magnetic resonance spectroscopy may serve as a complementary imaging biomarker for monitoring response to therapy in osteoporosis.

(1)H-magnetic resonance spectroscopy in social anxiety disorder.

PubMed

Howells, Fleur M; Hattingh, Coenraad J; Syal, Supriya; Breet, Elsie; Stein, Dan J; Lochner, Christine

2015-04-03

Social anxiety disorder (SAD) is characterized by excessive anxiety about social interaction or performance situations, leading to avoidance and clinically significant distress. A growing literature on the neurobiology of SAD has suggested that the reward/avoidance basal ganglia circuitry in general and the glutamatergic system in particular may play a role. In the current study, we investigated (1)H-magnetic resonance spectroscopy ((1)H-MRS) concentrations in cortical, striatal, and thalamic circuitry, as well as their associations with measures of social anxiety and related symptoms, in patients with primary SAD. Eighteen adult individuals with SAD and 19 age- and sex- matched controls participated in this study. (1)H-MRS was used to determine relative metabolite concentrations in the anterior cingulate cortex (ACC) using single voxel spectroscopy (reporting relative N-acetyl-aspartate (NAA), N-acetyl-aspartate with N-acetyl-aspartyl-glutamate (NAA+NAAG), glycerophosphocholine with phosphocholine (GPC+PCh), myo-inositol, glutamate (Glu), and glutamate with its precursor glutamine (Glu+Gln)), and the caudate, putamen and thalami bilaterally using two dimensional chemical shift imaging (reporting relative NAA+NAAG and GPC+PCh). Relationships between metabolite concentrations and measures of social anxiety and related symptoms were also determined. Measures of social anxiety included symptom severity, blushing propensity, and gaze anxiety/avoidance. We found, first, decreased relative glutamate concentration in the ACC of SAD and changes in myo-inositol with measures of social anxiety. Second, NAA metabolite concentration was increased in thalamus of SAD, and choline metabolite concentrations were related to measures of social anxiety. Lastly, choline metabolite concentration in the caudate and putamen showed changes in relation to measures of social anxiety. These findings are consistent with evidence that the reward/avoidance basal ganglia circuitry, as well as

The nuclear electric quadrupole moment of copper.

PubMed

Santiago, Régis Tadeu; Teodoro, Tiago Quevedo; Haiduke, Roberto Luiz Andrade

2014-06-21

The nuclear electric quadrupole moment (NQM) of the (63)Cu nucleus was determined from an indirect approach by combining accurate experimental nuclear quadrupole coupling constants (NQCCs) with relativistic Dirac-Coulomb coupled cluster calculations of the electric field gradient (EFG). The data obtained at the highest level of calculation, DC-CCSD-T, from 14 linear molecules containing the copper atom give rise to an indicated NQM of -198(10) mbarn. Such result slightly deviates from the previously accepted standard value given by the muonic method, -220(15) mbarn, although the error bars are superimposed.

Improved Cardiac Proton Magnetic Resonance Spectroscopy at 3 T Using High Permittivity Pads.

PubMed

de Heer, Paul; Bizino, Maurice B; Versluis, Maarten J; Webb, Andrew G; Lamb, Hildo J

2016-02-01

The aim of this study was to determine whether high permittivity (HP) pads can be used to increase the signal-to-noise ratio (SNR) of cardiac proton magnetic resonance spectroscopy at 3 T, allowing faster data acquisition. The institutional review board approved the study protocol, and written informed consent was obtained from all participants. In 22 healthy volunteers, water-suppressed localized spectra were acquired in the interventricular septum without and with HP pads. The SNR and myocardial triglyceride content (MTGC) were measured without and with the HP pads, and the results were compared with a paired sample Student t test. Application of HP pads increased mean (SD) SNR from 27.9 (15.6) to 42.3 (24.4) (P < 0.0001), a mean gain of 60%. The acquisition time can thereby be reduced from just under 5 minutes to just under 2 minutes while maintaining the same SNR. The mean (SD) MTGC was 0.39% (0.17%) without pads and 0.38% (0.15%) with pads (P = 0.83) for the healthy volunteers, showing that no bias is introduced by using the pads. No difference in spectral linewidth was measured (P = 0.80), the values being 17.4 (4.9) Hz without and 17.1 (3.2) Hz with pads. Both transmit and receive maps showed increases in sensitivity due to the presence of the HP pads. High permittivity pads improve cardiac proton magnetic resonance spectroscopy at 3 T by increasing the SNR on average by 60%, which can be used to reduce data acquisition time significantly, allowing fast assessment of MTGC without compromising spectral quality. The SNR increase arises primarily from the increase in receive sensitivity of the phased array, which is more closely coupled to the body via the HP pads. In addition, the transmit efficiency is also increased, allowing shorter or lower power radiofrequency pulses.

Myo-inositol metabolism in appropriately grown and growth-restricted fetuses: a proton magnetic resonance spectroscopy study.

PubMed

Story, Lisa; Damodaram, Mellisa S; Supramaniam, Veena; Allsop, Joanna M; Mcguinness, Amy; Patel, Abhilasha; Wylezinska, Marzena; Kumar, Sailesh; Rutherford, Mary A

2013-09-01

Myo-inositol (Myo-ins) is a marker of neuroglial cells, being present in the astrocytes of brain tissue, but also functions as an osmolyte. Numbers of astrocytes are known to increase following injury to the brain. Growth-restricted fetuses are at increased risk of later neurodevelopmental impairments even in the absence of overt lesions and despite preserved/increased cerebral blood flow. This study aims to investigate brain Myo-ins metabolism in fetuses with intrauterine growth restriction (IUGR) and evidence of cerebral redistribution using magnetic resonance spectroscopy (MRS) at a short echo time. Biometry and Doppler assessment of blood flow was assessed using ultrasound in 28 fetuses with IUGR and 47 appropriately grown control subjects. MRI was used to exclude overt brain injury. Proton magnetic resonance spectroscopy of the fetal brain was then performed at an echo time of 42 ms to examine the Myo-ins:Choline (Cho), Myo-ins:Creatine (Cr) and Cho:Cr ratios. No alterations in brain Myo-ins:Cho, Myo-ins:Cr or Cho:Cr ratios were detected between appropriately grown and growth restricted fetuses. IUGR is not associated with a measureable difference in brain myo-inositol ratios. This may be due to the protective effects of preserved cerebral blood flow in growth restriction and comparable astrocyte numbers when compared to controls. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Detection of human immunodeficiency virus induced inflammation and oxidative stress in lenticular nuclei with magnetic resonance spectroscopy despite antiretroviral therapy.

PubMed

Roc, Anne C; Ances, Beau M; Chawla, Sanjeev; Korczykowski, Marc; Wolf, Ronald L; Kolson, Dennis L; Detre, John A; Poptani, Harish

2007-09-01

Single-voxel magnetic resonance spectroscopy measurements of N-acetyl aspartate, choline, and creatine (Cr) are affected in patients with human immunodeficiency virus (HIV) and neurocognitive impairment. However, these metabolic markers are often normalized in affected central nervous system regions, such as the lenticular nuclei, after initiation of highly active antiretroviral therapy (HAART). To examine whether lactate (Lac), a marker of inflammation and anaerobic glycolysis, and lipid, an indicator of cell membrane turnover resulting from oxidative stress, could serve as surrogate biomarkers within the lenticular nuclei of HIV-positive patients with different degrees of neurocognitive impairment. Three-tesla 2-dimensional-chemical shift imaging magnetic resonance spectroscopy at echo times of 30 milliseconds and 135 milliseconds was performed in voxels overlapping the lenticular nuclei of seronegative controls and a spectrum of HIV-positive patients (neurocognitively normal, mildly impaired, or moderately to severely impaired). University of Pennsylvania, Philadelphia. Ten seronegative controls and 45 HIV-positive patients with different degrees of neurocognitive impairment (15 neurocognitively normal patients, 12 mildly impaired patients, and 18 moderately to severely impaired patients). In vivo 2-dimensional-chemical shift imaging magnetic resonance spectroscopy analysis of N-acetyl aspartate:Cr, choline:Cr, Lac:Cr, and (lipid + Lac):Cr ratios among the various groups. In addition, the effect of the degree of HAART central nervous system penetration (high vs low) on these ratios was studied. No significant lenticular nuclei atrophy was detected with volumes similar across all of the groups. Both N-acetyl aspartate:Cr and choline:Cr ratios were similar across all of the groups at either echo time. In contrast, the Lac:Cr ratio was significantly greater in HIV-positive patients with moderate to severe impairment compared with seronegative controls. The (lipid

TOPICAL REVIEW: Spatial localization in nuclear magnetic resonance spectroscopy

NASA Astrophysics Data System (ADS)

Keevil, Stephen F.

2006-08-01

The ability to select a discrete region within the body for signal acquisition is a fundamental requirement of in vivo NMR spectroscopy. Ideally, it should be possible to tailor the selected volume to coincide exactly with the lesion or tissue of interest, without loss of signal from within this volume or contamination with extraneous signals. Many techniques have been developed over the past 25 years employing a combination of RF coil properties, static magnetic field gradients and pulse sequence design in an attempt to meet these goals. This review presents a comprehensive survey of these techniques, their various advantages and disadvantages, and implications for clinical applications. Particular emphasis is placed on the reliability of the techniques in terms of signal loss, contamination and the effect of nuclear relaxation and J-coupling. The survey includes techniques based on RF coil and pulse design alone, those using static magnetic field gradients, and magnetic resonance spectroscopic imaging. Although there is an emphasis on techniques currently in widespread use (PRESS, STEAM, ISIS and MRSI), the review also includes earlier techniques, in order to provide historical context, and techniques that are promising for future use in clinical and biomedical applications.

Masquerading Orbital Abscess Following Attempted Hydrogel Scleral Buckle Removal: Diagnostic Value of Orbital Magnetic Resonance Spectroscopy.

PubMed

Pakdel, Farzad; Hadizadeh, Homayoun; Pirmarzdashty, Niloofar; Kiavash, Victoria

2015-01-01

A 59-year-old patient developed acute proptosis, peri-orbital swelling and restriction of ocular movements 2 days after attempted scleral buckle removal. Initial clinical and orbital MRI findings were suggestive for orbital cellulitis and orbital abscess. Empiric intravenous antibiotics were not effective. Proton magnetic resonance spectroscopy (MRS) revealed a distinctive composition and helped rule out suppurative and neoplastic processes. The patient recovered soon after removing clear liquefied and tiny particles of the hydrogel buckle by an effective peristaltic technique.

Chemical Principles Revisited. Proton Magnetic Resonance Spectroscopy.

ERIC Educational Resources Information Center

McQuarrie, Donald A.

1988-01-01

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

Coherent resonance stop bands in alternating gradient beam transport

NASA Astrophysics Data System (ADS)

Ito, K.; Okamoto, H.; Tokashiki, Y.; Fukushima, K.

2017-06-01

An extensive experimental study is performed to confirm fundamental resonance bands of an intense hadron beam propagating through an alternating gradient linear transport channel. The present work focuses on the most common lattice geometry called "FODO" or "doublet" that consists of two quadrupoles of opposite polarities. The tabletop ion-trap system "S-POD" (Simulator of Particle Orbit Dynamics) developed at Hiroshima University is employed to clarify the parameter-dependence of coherent beam instability. S-POD can provide a non-neutral plasma physically equivalent to a charged-particle beam in a periodic focusing potential. In contrast with conventional experimental approaches relying on large-scale machines, it is straightforward in S-POD to control the doublet geometry characterized by the quadrupole filling factor and drift-space ratio. We verify that the resonance feature does not essentially change depending on these geometric factors. A few clear stop bands of low-order resonances always appear in the same pattern as previously found with the sinusoidal focusing model. All stop bands become widened and shift to the higher-tune side as the beam density is increased. In the space-charge-dominated regime, the most dangerous stop band is located at the bare betatron phase advance slightly above 90 degrees. Experimental data from S-POD suggest that this severe resonance is driven mainly by the linear self-field potential rather than by nonlinear external imperfections and, therefore, unavoidable at high beam density. The instability of the third-order coherent mode generates relatively weak but noticeable stop bands near the phase advances of 60 and 120 degrees. The latter sextupole stop band is considerably enhanced by lattice imperfections. In a strongly asymmetric focusing channel, extra attention may have to be paid to some coupling resonance lines induced by the Coulomb potential. Our interpretations of experimental data are supported by theoretical

Is magnetic resonance spectroscopy capable of detecting metabolic abnormalities in neurofibromatosis type 1 that are not revealed in brain parenchyma of normal appearance?

PubMed

Rodrigues, Antonio Carlos Pondé; Ferraz-Filho, José Roberto Lopes; Torres, Ulysses S; da Rocha, Antônio José; Muniz, Marcos Pontes; Souza, Antônio Soares; Goloni-Bertollo, Eny Maria; Pavarino, Érika Cristina

2015-03-01

Results of magnetic resonance spectroscopy studies in normal-appearing brain and in non-neoplastic brain lesions in individuals with neurofibromatosis type 1 (NF1) have been discrepant. We used magnetic resonance spectroscopy to analyze the metabolic patterns in the basal ganglia of patients with NF1 and examine their correlation with focal hyperintense lesions in T2-weighted images (T2-weighted hyperintensities). We used magnetic resonance spectroscopy data of 42 individuals with NF1 (18 with and 24 without T2- weighted hyperintensities) and 25 controls matched for gender and age. A single-voxel technique was employed by manually placing a region of interest with a uniform size over a predetermined anatomical region including the globus pallidum and putamen (capsulolenticular region). We further analyzed the ratios of choline/creatine, N-acetyl aspartate (NAA)/creatine, and myoinositol/creatine metabolites and the occurrence of T2-weighted hyperintensities in these regions in individuals with NF1. There was a significant difference between the NF1 and control groups with regard to the mean values of myoinositol/creatine and choline/creatine, with higher metabolite values observed in the NF1 group (P < 0.001). Only the myoinositol/creatine ratio was able to discriminate between NF1 subgroups with and without T2-weighted hyperintensities. For the NAA/creatine ratio, there was no significant difference between the NF1 and the control groups. Magnetic resonance spectroscopy allows the characterization of tissue abnormalities not demonstrable in the structural images of individuals with NF1 through choline and myoinositol metabolite analysis. Yet the preserved NAA values argue against demyelination and axonal degeneration occurring in the region, suggesting instead a functional neuronal stability. Taken in association with the findings of lack of clinical manifestations and the known transient nature of T2-weighted hyperintensities in NF1 as demonstrated by other

Optimization of metabolite detection by quantum mechanics simulations in magnetic resonance spectroscopy.

PubMed

Gambarota, Giulio

2017-07-15

Magnetic resonance spectroscopy (MRS) is a well established modality for investigating tissue metabolism in vivo. In recent years, many efforts by the scientific community have been directed towards the improvement of metabolite detection and quantitation. Quantum mechanics simulations allow for investigations of the MR signal behaviour of metabolites; thus, they provide an essential tool in the optimization of metabolite detection. In this review, we will examine quantum mechanics simulations based on the density matrix formalism. The density matrix was introduced by von Neumann in 1927 to take into account statistical effects within the theory of quantum mechanics. We will discuss the main steps of the density matrix simulation of an arbitrary spin system and show some examples for the strongly coupled two spin system. Copyright © 2016 Elsevier Inc. All rights reserved.

Real time studies of Elastic Moduli Pu Aging using Resonant Ultrasound Spectroscopy

NASA Astrophysics Data System (ADS)

Maiorov, Boris

Elastic moduli are fundamental thermodynamic susceptibilities that connect directly to thermodynamics, electronic structure and give important information about mechanical properties. To determine the time evolution of the elastic properties in 239Pu and it Ga alloys, is imperative to study its phase stability and self-irradiation damage process. The most-likely sources of these changes include a) ingrowth of radioactive decay products like He and U, b) the introduction of radiation damage, c) δ-phase instabilities towards α-Pu or to Pu3Ga. The measurement of mechanical resonance frequencies can be made with extreme precision and used to compute the elastic moduli without corrections giving important insight in this problem. Using Resonant Ultrasound Spectroscopy, we measured the time dependence of the mechanical resonance frequencies of fine-grained polycrystalline δ-phase 239Pu, from 300K up to 480K. At room temperature, the shear modulus shows an increase in time (stiffening), but the bulk modulus decreases (softening). These are the first real-time measurements of room temperature aging of the elastic moduli, and the changes are consistent with elastic moduli measurements performed on 44 year old δ-Pu. As the temperature is increased, the rate of change increases exponentially, with both moduli becoming stiffer with time. For T>420K an abrupt change in the time dependence is observed indicating that the bulk and shear moduli have opposite rates of change. Our measurements provide a basis for ruling out the decomposition of δ-Pu towards α-Pu or Pu3Ga, and indicate a complex defect-related scenario from which we are gathering important clues.

Form factors of the d*(2380 ) resonance

NASA Astrophysics Data System (ADS)

Dong, Yubing; Shen, Pengnian; Zhang, Zongye

2018-06-01

In order to explore the possible physical quantities for judging different structures of the newly observed resonance d*(2380 ), we study its electromagnetic form factors. In addition to the electric charge monopole C 0 , we calculate its electric quadrupole E 2 , magnetic dipole M 1 , and magnetic octupole M 3 form factors on the base of the realistic coupled Δ Δ +C8C8 channel d* wave function with both the S - and D -partial waves. The results show that the magnetic dipole moment and electric quadrupole deformation of d* are 7.602 and 2.53 ×10-2 fm2 , respectively. The calculated magnetic dipole moment in the naive constituent quark model is also compared with the result of D12π picture. By comparing with partial results where the d* state is considered with a single Δ Δ and with a D12π structures, we find that in addition to the charge distribution of d*, the magnetic dipole moment and magnetic radius can be used to discriminate different structures of d*. Moreover, a quite small electric quadrupole deformation indicates that d* is more inclined to a slightly oblate shape due to our compact hexaquark dominated structure of d*.

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

PubMed Central

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

2008-01-01

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

Electronic properties of atomic layer deposition films, anatase and rutile TiO2 studied by resonant photoemission spectroscopy

NASA Astrophysics Data System (ADS)

Das, C.; Richter, M.; Tallarida, M.; Schmeisser, D.

2016-07-01

The TiO2 films are prepared by atomic layer deposition (ALD) method using titanium isopropoxide precursors at 250 °C and analyzed using resonant photoemission spectroscopy (resPES). We report on the Ti2p and O1s core levels, on the valence band (VB) spectra and x-ray absorption spectroscopy (XAS) data, and on the resonant photoelectron spectroscopy (resPES) profiles at the O1s and the Ti3p absorption edges. We determine the elemental abundance, the position of the VB maxima, the partial density of states (PDOS) in the VB and in the conduction band (CB) and collect these data in a band scheme. In addition, we analyze the band-gap states as well as the intrinsic states due to polarons and charge-transfer excitations. These states are found to cause multiple Auger decay processes upon resonant excitation. We identify several of these processes and determine their relative contribution to the Auger signal quantitatively. As our resPES data allow a quantitative analysis of these defect states, we determine the relative abundance of the PDOS in the VB and in CB and also the charge neutrality level. The anatase and rutile polymorphs of TiO2 are analyzed in the same way as the TiO2 ALD layer. The electronic properties of the TiO2 ALD layer are compared with the anatase and rutile polymorphs of TiO2. In our comparative study, we find that ALD has its own characteristic electronic structure that is distinct from that of anatase and rutile. However, many details of the electronic structure are comparable and we benefit from our spectroscopic data and our careful analysis to find these differences. These can be attributed to a stronger hybridization of the O2p and Ti3d4s states for the ALD films when compared to the anatase and rutile polymorphs.

Investigation of Antioxidant Activity of Pomegranate Juices by Means of Electron Paramagnetic Resonance and UV-Vis Spectroscopy.

PubMed

Kozik, Violetta; Jarzembek, Krystyna; Jędrzejowska, Agnieszka; Bąk, Andrzej; Polak, Justyna; Bartoszek, Mariola; Pytlakowska, Katarzyna

2015-01-01

Pomegranate fruit (Punica granatum L.) is a source of numerous phenolic compounds, and it contains flavonoids such as anthocyanins, anthocyanidins, cyanidins, catechins and other complexes of flavonoids, ellagitannins, and hydrolyzed tannins. Pomegranate juice shows antioxidant, antiproliferative, and anti-atherosclerotic properties. The antioxidant capacity (TEAC) of the pomegranate juices was measured using electron paramagnetic resonance (EPR) spectroscopy and 1,1-diphenyl-2-picrylhydrazyl (DPPH•) as a source of free radicals, and the total phenolic (TP) content was measured using UV-Vis spectroscopy. All the examined pomegranate juices exhibited relatively high antioxidant properties. The TEAC values determined by means of EPR spectroscopy using Trolox (TE) as a free radical scavenger were in the range of 463.12 to 1911.91 μmol TE/100 mL juice. The TP content measured by the Folin-Ciocalteu method, using gallic acid (GA) as a free radical scavenger, widely varied in the investigated pomegranate juice samples and ranged from 1673.62 to 5263.87 mg GA/1 L juice. The strongest antioxidant properties were observed with the fresh pomegranate juices obtained from the fruits originating from Israel, Lebanon, and Azerbaijan. Correlation analysis of numerical data obtained by means of EPR spectroscopy (TEAC) and UV-Vis spectroscopy (TP) gave correlation coefficient (r)=0.90 and determination coefficient (r2)=0.81 (P<0.05).

Study of a micro chamber quadrupole mass spectrometer

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

Wang Jinchan; Zhang Xiaobing; Mao Fuming

The design of a micro chamber quadrupole mass spectrometer (MCQMS) having a small total volume of only 20 cm{sup 3}, including Faraday cup ion detector and ion source, is described. This MCQMS can resist a vacuum baking temperature of 400-500 deg. C. The quadrupole elements with a hyperbolic surface are made of a ceramic material and coated with a thin metal layer. The quadrupole mass filter has a field radius of 3 mm and a length of 100 mm. Prototypes of this new MCQMS can detect a minimum partial pressure of 10{sup -8} Pa, have a peak width of {delta}M=1more » at 10% peak height from mass number 1 to 60, and show an excellent long-term stability. The new MCQMS is intended to be used in residual gas analyses of electron devices during a mutual pumping and baking process.« less

Magnetic-field-controlled negative differential conductance in scanning tunneling spectroscopy of graphene npn junction resonators

NASA Astrophysics Data System (ADS)

Li, Si-Yu; Liu, Haiwen; Qiao, Jia-Bin; Jiang, Hua; He, Lin

2018-03-01

Negative differential conductance (NDC), characterized by the decreasing current with increasing voltage, has attracted continuous attention for its various novel applications. The NDC typically exists in a certain range of bias voltages for a selected system and controlling the regions of NDC in curves of current versus voltage (I -V ) is experimentally challenging. Here, we demonstrate a magnetic-field-controlled NDC in scanning tunneling spectroscopy of graphene npn junction resonators. The magnetic field not only can switch on and off the NDC, but also can continuously tune the regions of the NDC in the I -V curves. In the graphene npn junction resonators, magnetic fields generate sharp and pronounced Landau-level peaks with the help of the Klein tunneling of massless Dirac fermions. A tip of scanning tunneling microscope induces a relatively shift of the Landau levels in graphene beneath the tip. Tunneling between the misaligned Landau levels results in the magnetic-field-controlled NDC.

Microwave spectroscopy of biomolecular building blocks.

PubMed

Alonso, José L; López, Juan C

2015-01-01

Microwave spectroscopy, considered as the most definitive gas phase structural probe, is able to distinguish between different conformational structures of a molecule, because they have unique spectroscopic constants and give rise to distinct individual rotational spectra.Previously, application of this technique was limited to molecular specimens possessing appreciable vapor pressures, thus discarding the possibility of studying many other molecules of biological importance, in particular those with high melting points, which had a tendency to undergo thermal reactions, and ultimately degradation, upon heating.Nowadays, the combination of laser ablation with Fourier transform microwave spectroscopy techniques, in supersonic jets, has enabled the gas-phase study of such systems. In this chapter, these techniques, including broadband spectroscopy, as well as results of their application into the study of the conformational panorama and structure of biomolecular building blocks, such as amino acids, nucleic bases, and monosaccharides, are briefly discussed, and with them, the tools for conformational assignation - rotational constants, nuclear quadrupole coupling interaction, and dipole moment.

Comparison of conventional and novel quadrupole drift tube magnets inspired by Klaus Halbach

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

Feinberg, B.

1995-02-01

Quadrupole drift tube magnets for a heavy-ion linac provide a demanding application of magnet technology. A comparison is made of three different solutions to the problem of providing an adjustable high-field-strength quadrupole magnet in a small volume. A conventional tape-wound electromagnet quadrupole magnet (conventional) is compared with an adjustable permanent-magnet/iron quadrupole magnet (hybrid) and a laced permanent-magnet/iron/electromagnet (laced). Data is presented from magnets constructed for the SuperHILAC heavy-ion linear accelerator, and conclusions are drawn for various applications.

Magnetic resonance spectroscopy.

PubMed

Hope, P L; Moorcraft, J

1991-09-01

MRS is a noninvasive technique that does not use ionizing radiation and can be used to measure relative metabolite concentrations in human tissues and organs in vivo. Phosphorus MRS can be used to study energy metabolites and intracellular pH. The first neonatal applications were described in 1983 in a study of cerebral metabolism. Since then, the value of cerebral MRS as research tool and an investigative technique has been confirmed, and its prognostic power in asphyxiated infants has been established. Techniques of spatial localization and quantitation have been developed, but studies of other organs and the use of other nuclei remain at a very preliminary stage. Considering the huge potential of MRS and the proliferation of high field magnets primarily designed for imaging, there has been a disappointing lack of progress in the development of clinical and research applications of spectroscopy. The logistic differences of studying sick infants in strong magnetic fields make MRS a time-consuming and labor-intensive investigation, which will inevitably limit its widespread routine use. Research studies are hampered by the diversity of spectroscopic and signal processing techniques, which make comparisons of data from different groups impossible. Some techniques for the assessment of cerebral hemodynamics such as doppler ultrasound and near infrared spectroscopy have the advantage of being available at the cotside, but MRS is unique in providing quantitative information about a wide range of intracellular metabolites. The altricial development of MRS as a clinical investigative tool in neonatology can be ascribed partly to practical difficulties, but these should not detract from the exciting possibilities opened up by a technique that gives a noninvasive insight into intracellular chemistry. The metabolic information from MRS is an invaluable addition to the information provided by other techniques and will certainly play an important role in unraveling the

Dynamical quadrupole structure factor of frustrated ferromagnetic chain

NASA Astrophysics Data System (ADS)

Onishi, Hiroaki

2018-05-01

We investigate the dynamical quadrupole structure factor of a spin-1/2 J1-J2 Heisenberg chain with competing ferromagnetic J1 and antiferromagnetic J2 in a magnetic field by exploiting density-matrix renormalization group techniques. In a field-induced spin nematic regime, we observe gapless excitations at q = π according to quasi-long-range antiferro-quadrupole correlations. The gapless excitation mode has a quadratic form at the saturation, while it changes into a linear dispersion as the magnetization decreases.

Localized surface plasmon resonances in nanostructures to enhance nonlinear vibrational spectroscopies: towards an astonishing molecular sensitivity

PubMed Central

2014-01-01

Summary Vibrational transitions contain some of the richest fingerprints of molecules and materials, providing considerable physicochemical information. Vibrational transitions can be characterized by different spectroscopies, and alternatively by several imaging techniques enabling to reach sub-microscopic spatial resolution. In a quest to always push forward the detection limit and to lower the number of needed vibrational oscillators to get a reliable signal or imaging contrast, surface plasmon resonances (SPR) are extensively used to increase the local field close to the oscillators. Another approach is based on maximizing the collective response of the excited vibrational oscillators through molecular coherence. Both features are often naturally combined in vibrational nonlinear optical techniques. In this frame, this paper reviews the main achievements of the two most common vibrational nonlinear optical spectroscopies, namely surface-enhanced sum-frequency generation (SE-SFG) and surface-enhanced coherent anti-Stokes Raman scattering (SE-CARS). They can be considered as the nonlinear counterpart and/or combination of the linear surface-enhanced infrared absorption (SEIRA) and surface-enhanced Raman scattering (SERS) techniques, respectively, which are themselves a branching of the conventional IR and spontaneous Raman spectroscopies. Compared to their linear equivalent, those nonlinear vibrational spectroscopies have proved to reach higher sensitivity down to the single molecule level, opening the way to astonishing perspectives for molecular analysis. PMID:25551056

Energetic ion mass analysis using a radio-frequency quadrupole filter.

PubMed

Medley, S S

1978-06-01

In conventional applications of the radio-frequency quadrupole mass analyzer, the ion injection energy is usually limited to less than the order of 100 eV due to constraints on the dimensions and power supply of the device. However, requirements often arise, for example in fusion plasma ion diagnostics, for mass analysis of much more energetic ions. A technique easily adaptable to any conventional quadrupole analyzer which circumvents the limitation on injection energy is documented in this paper. Briefly, a retarding potential applied to the pole assembly is shown to facilitate mass analysis of multikiloelectron volt ions without altering the salient characteristics of either the quadrupole filter or the ion beam.

Collisional Processes Probed by using Resonant Four-Wave Mixing Spectroscopy

NASA Astrophysics Data System (ADS)

McCormack, E. F.; Stampanoni, A.; Hemmerling, B.

2000-06-01

Collisionally-induced decay processes in excited-state nitric oxide (NO) have been measured by using time-resolved two-color, resonant four-wave mixing (TC-RFWM) spectroscopy and polarization spectroscopy (PS). Markedly different time dependencies were observed in the data obtained by using TC-RFWM when compared to PS. Oscillations in the PS signal as a function of delay between the pump and probe laser pulses were observed and it was determined that their characteristics depend very sensitively on laser polarization. Analysis reveals that the oscillations in the decay curves are due to coherent excitation of unresolved hyperfine structure in the A state of NO. A comparison of beat frequencies obtained by taking Fourier transforms of the time data to the predicted hyperfine structure of the A state support this explanation. Further, based on a time-dependent model of PS as a FWM process, the signal’s dependence as a function of time on polarization configuration and excitation scheme can be predicted. By using the beat frequency values, fits of the model results to experimental decay curves for different pressures allows a study of the quenching rate in the A state due to collisional processes. A comparison of the PS data to laser-induced fluorescence decay measurements reveals different decay rates which suggests that the PS signal decay depends on the orientation and alignment of the excited molecules. The different behavior of the decay curves obtained by using TC-RFWM and PS can be understood in terms of the various contributions to the decay as described by the model and this has a direct bearing on which technique is preferable for a given set of experimental parameters.

Complete elastic constants of α-BaB2O4: Schaefer-Bergmann acousto-optic diffraction and resonant ultrasound spectroscopy.

PubMed

Pfeiffer, Jonathan B; Wagner, Kelvin H; Kaufman, Yaniv; Ledbetter, Hassel; Soos, Jolanta; Diestler, Mark

2016-10-01

Both Schaefer-Bergmann diffraction and resonant ultrasound spectroscopy were used to measure the six independent elastic-stiffness coefficients of the trigonal, non-piezoelectric crystal α-BaB 2 O 4 . The two measurement sets resulted in a root-mean-square variance of 1.2%. This paper provides a detailed analysis of the two different measurement techniques and discusses the similarities and differences.

Cerebellar Volume and Proton Magnetic Resonance Spectroscopy at Term, and Neurodevelopment at 2 Years of Age in Preterm Infants

ERIC Educational Resources Information Center

van Kooij, Britt J. M.; Benders, Manon J. N. L.; Anbeek, Petronella; van Haastert, Ingrid C.; de Vries, Linda S.; Groenendaal, Floris

2012-01-01

Aim: To assess the relation between cerebellar volume and spectroscopy at term equivalent age, and neurodevelopment at 24 months corrected age in preterm infants. Methods: Magnetic resonance imaging of the brain was performed around term equivalent age in 112 preterm infants (mean gestational age 28wks 3d [SD 1wk 5d]; birthweight 1129g [SD 324g]).…

Antiferromagnetic spin fluctuations and unconventional nodeless superconductivity in an iron-based new superconductor (Ca4Al2O(6-y))(Fe2As2): 75As nuclear quadrupole resonance study.

PubMed

Kinouchi, H; Mukuda, H; Yashima, M; Kitaoka, Y; Shirage, P M; Eisaki, H; Iyo, A

2011-07-22

We report 75As nuclear quadrupole resonance studies on (Ca4Al2O(6-y))(Fe2As2) with T(c) = 27  K. Measurement of nuclear-spin-relaxation rate 1/T1 has revealed a significant development of two-dimensional antiferromagnetic spin fluctuations down to T(c) in association with the smallest As-Fe-As bond angle. Below T(c), the temperature dependence of 1/T1 without any trace of the coherence peak is well accounted for by a nodeless s(±)-wave multiple-gaps model. From the fact that its T(c) is comparable to T(c) = 28  K in the optimally doped LaFeAsO(1-y) in which antiferromagnetic spin fluctuations are not dominant, we remark that antiferromagnetic spin fluctuations are not a unique factor for enhancing T(c) among Fe-based superconductors, but a condition for optimizing superconductivity should be addressed from the lattice structure point of view.

Comparison of magnetic resonance imaging-compatible optical detectors for in-magnet tissue spectroscopy: photodiodes versus silicon photomultipliers

PubMed Central

El-Ghussein, Fadi; Jiang, Shudong; Pogue, Brian W.; Paulsen, Keith D.

2014-01-01

Abstract. Tissue spectroscopy inside the magnetic resonance imaging (MRI) system adds a significant value by measuring fast vascular hemoglobin responses or completing spectroscopic identification of diagnostically relevant molecules. Advances in this type of spectroscopy instrumentation have largely focused on fiber coupling into and out of the MRI; however, nonmagnetic detectors can now be placed inside the scanner with signal amplification performed remotely to the high field environment for optimized light detection. In this study, the two possible detector options, such as silicon photodiodes (PD) and silicon photomultipliers (SiPM), were systematically examined for dynamic range and wavelength performance. Results show that PDs offer 108 (160 dB) dynamic range with sensitivity down to 1 pW, whereas SiPMs have 107 (140 dB) dynamic range and sensitivity down to 10 pW. A second major difference is the spectral sensitivity of the two detectors. Here, wavelengths in the 940 nm range are efficiently captured by PDs (but not SiPMs), likely making them the superior choice for broadband spectroscopy guided by MRI. PMID:25006986

Two-colour dip spectroscopy of jet-cooled molecules

NASA Astrophysics Data System (ADS)

Ito, Mitsuo

In optical-optical double resonance spectroscopy, the resonance transition from an intermediate state to a final state can be detected by a dip of the signal (fluorescence or ion) associated with the intermediate state. This method probing the signal of the intermediate state may be called `two-colour dip spectroscopy'. Various kinds of two-colour dip spectroscopy such as two-colour fluorescence/ion dip spectroscopy, two-colour ionization dip spectroscopy employing stimulated emission, population labelling spectroscopy and mass-selected ion dip spectroscopy with dissociation were briefly described, paying special attention to their characteristics in excitation, detection and application. They were extensively and successfully applied to jet-cooled large molecules and provided us with new useful information on the energy and dynamics of excited molecules.

Higher order parametric excitation modes for spaceborne quadrupole mass spectrometers

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

Gershman, D. J.; Block, B. P.; Rubin, M.

This paper describes a technique to significantly improve upon the mass peak shape and mass resolution of spaceborne quadrupole mass spectrometers (QMSs) through higher order auxiliary excitation of the quadrupole field. Using a novel multiresonant tank circuit, additional frequency components can be used to drive modulating voltages on the quadrupole rods in a practical manner, suitable for both improved commercial applications and spaceflight instruments. Auxiliary excitation at frequencies near twice that of the fundamental quadrupole RF frequency provides the advantages of previously studied parametric excitation techniques, but with the added benefit of increased sensed excitation amplitude dynamic range and themore » ability to operate voltage scan lines through the center of upper stability islands. Using a field programmable gate array, the amplitudes and frequencies of all QMS signals are digitally generated and managed, providing a robust and stable voltage control system. These techniques are experimentally verified through an interface with a commercial Pfeiffer QMG422 quadrupole rod system. When operating through the center of a stability island formed from higher order auxiliary excitation, approximately 50% and 400% improvements in 1% mass resolution and peak stability were measured, respectively, when compared with traditional QMS operation. Although tested with a circular rod system, the presented techniques have the potential to improve the performance of both circular and hyperbolic rod geometry QMS sensors.« less

The Rhic Azimuth Quadrupole:. "perfect Liquid" or Gluonic Radiation?

NASA Astrophysics Data System (ADS)

Trainor, Thomas A.

Large elliptic flow at RHIC seems to indicate that ideal hydrodynamics provides a good description of Au-Au collisions, at least at the maximum RHIC energy. The medium formed has been interpreted as a nearly perfect (low-viscosity) liquid, and connections have been made to gravitation through string theory. Recently, claimed observations of large flow fluctuations comparable to participant eccentricity fluctuations seem to confirm the ideal hydro scenario. However, determination of the azimuth quadrupole with 2D angular autocorrelations, which accurately distinguish "flow" (quadrupole) from "nonflow" (minijets), contradicts conventional interpretations. Centrality trends may depend only on the initial parton geometry, and methods used to isolate flow fluctuations are sensitive instead mainly to minijet correlations. The results presented in this paper suggest that the azimuth quadrupole may be a manifestation of gluonic multipole radiation.

Communication: On the isotope anomaly of nuclear quadrupole coupling in molecules

NASA Astrophysics Data System (ADS)

Filatov, Michael; Zou, Wenli; Cremer, Dieter

2012-10-01

The dependence of the nuclear quadrupole coupling constants (NQCC) on the interaction between electrons and a nucleus of finite size is theoretically analyzed. A deviation of the ratio of the NQCCs obtained from two different isotopomers of a molecule from the ratio of the corresponding bare nuclear electric quadrupole moments, known as quadrupole anomaly, is interpreted in terms of the logarithmic derivatives of the electric field gradient at the nuclear site with respect to the nuclear charge radius. Quantum chemical calculations based on a Dirac-exact relativistic methodology suggest that the effect of the changing size of the Au nucleus in different isotopomers can be observed for Au-containing molecules, for which the predicted quadrupole anomaly reaches values of the order of 0.1%. This is experimentally detectable and provides an insight into the charge distribution of non-spherical nuclei.

Pulsed EPR investigations of systems modeling molybdenum enzymes: hyperfine and quadrupole parameters of oxo-17O in [Mo 17O(SPh)4]-.

PubMed

Astashkin, Andrei V; Neese, Frank; Raitsimring, Arnold M; Cooney, J Jon A; Bultman, Eric; Enemark, John H

2005-11-30

Ka band ESEEM spectroscopy was used to determine the hyperfine (hfi) and nuclear quadrupole (nqi) interaction parameters for the oxo-17O ligand in [Mo 17O(SPh)4]-, a spectroscopic model of the oxo-Mo(V) centers of enzymes. The isotropic hfi constant of 6.5 MHz found for the oxo-17O is much smaller than the values of approximately 20-40 MHz typical for the 17O nucleus of an equatorial OH(2) ligand in molybdenum enzymes. The 17O nqi parameter (e2qQ/h = 1.45 MHz, eta approximately = 0) is the first to be obtained for an oxo group in a metal complex. The parameters of the oxo-17O ligand, as well as other magnetic resonance parameters of [Mo 17O(SPh)4]- predicted by quasi-relativistic DFT calculations, were in good agreement with those obtained in experiment. From the electronic structure of the complex revealed by DFT, it follows that the SOMO is almost entirely molybdenum d(xy) and sulfur p, while the spin density on the oxo-17O is negative, determined by spin polarization mechanisms. The results of this work will enable direct experimental identification of the oxo ligand in a variety of chemical and biological systems.

Computational modelling of the piglet brain to simulate near-infrared spectroscopy and magnetic resonance spectroscopy data collected during oxygen deprivation

PubMed Central

Moroz, Tracy; Banaji, Murad; Robertson, Nicola J.; Cooper, Chris E.; Tachtsidis, Ilias

2012-01-01

We describe a computational model to simulate measurements from near-infrared spectroscopy (NIRS) and magnetic resonance spectroscopy (MRS) in the piglet brain. Piglets are often subjected to anoxic, hypoxic and ischaemic insults, as experimental models for human neonates. The model aims to help interpret measurements and increase understanding of physiological processes occurring during such insults. It is an extension of a previous model of circulation and mitochondrial metabolism. This was developed to predict NIRS measurements in the brains of healthy adults i.e. concentration changes of oxyhaemoglobin and deoxyhaemoglobin and redox state changes of cytochrome c oxidase (CCO). We altered and enhanced the model to apply to the anaesthetized piglet brain. It now includes metabolites measured by 31P-MRS, namely phosphocreatine, inorganic phosphate and adenosine triphosphate (ATP). It also includes simple descriptions of glycolysis, lactate dynamics and the tricarboxylic acid (TCA) cycle. The model is described, and its simulations compared with existing measurements from piglets during anoxia. The NIRS and MRS measurements are predicted well, although this requires a reduction in blood pressure autoregulation. Predictions of the cerebral metabolic rate of oxygen consumption (CMRO2) and lactate concentration, which were not measured, are given. Finally, the model is used to investigate hypotheses regarding changes in CCO redox state during anoxia. PMID:22279158

Computational modelling of the piglet brain to simulate near-infrared spectroscopy and magnetic resonance spectroscopy data collected during oxygen deprivation.

PubMed

Moroz, Tracy; Banaji, Murad; Robertson, Nicola J; Cooper, Chris E; Tachtsidis, Ilias

2012-07-07

We describe a computational model to simulate measurements from near-infrared spectroscopy (NIRS) and magnetic resonance spectroscopy (MRS) in the piglet brain. Piglets are often subjected to anoxic, hypoxic and ischaemic insults, as experimental models for human neonates. The model aims to help interpret measurements and increase understanding of physiological processes occurring during such insults. It is an extension of a previous model of circulation and mitochondrial metabolism. This was developed to predict NIRS measurements in the brains of healthy adults i.e. concentration changes of oxyhaemoglobin and deoxyhaemoglobin and redox state changes of cytochrome c oxidase (CCO). We altered and enhanced the model to apply to the anaesthetized piglet brain. It now includes metabolites measured by (31)P-MRS, namely phosphocreatine, inorganic phosphate and adenosine triphosphate (ATP). It also includes simple descriptions of glycolysis, lactate dynamics and the tricarboxylic acid (TCA) cycle. The model is described, and its simulations compared with existing measurements from piglets during anoxia. The NIRS and MRS measurements are predicted well, although this requires a reduction in blood pressure autoregulation. Predictions of the cerebral metabolic rate of oxygen consumption (CMRO(2)) and lactate concentration, which were not measured, are given. Finally, the model is used to investigate hypotheses regarding changes in CCO redox state during anoxia.

Cyclotron resonance spectroscopy in a high mobility two dimensional electron gas using characteristic matrix methods.

PubMed

Hilton, David J

2012-12-31

We develop a new characteristic matrix-based method to analyze cyclotron resonance experiments in high mobility two-dimensional electron gas samples where direct interference between primary and satellite reflections has previously limited the frequency resolution. This model is used to simulate experimental data taken using terahertz time-domain spectroscopy that show multiple pulses from the substrate with a separation of 15 ps that directly interfere in the time-domain. We determine a cyclotron dephasing lifetime of 15.1 ± 0.5 ps at 1.5 K and 5.0 ± 0.5 ps at 75 K.

Characterization of lipid oxidation process of beef during repeated freeze-thaw by electron spin resonance technology and Raman spectroscopy.

PubMed

Chen, Qingmin; Xie, Yunfei; Xi, Jinzhong; Guo, Yahui; Qian, He; Cheng, Yuliang; Chen, Yi; Yao, Weirong

2018-03-15

In this study, electron spin resonance (ESR) and Raman spectroscopy were applied to characterize lipid oxidation of beef during repeated freeze-thaw (RFT). Besides the conventional indexes including peroxide values (PV), thiobarbituric acid-reactive substances (TBARS) and acid values (AV) were evaluated, the radical and molecular structure changes were also measured by ESR and Raman spectroscopy. The results showed that PV, TBARS and AV were increased (P<0.05) after RFT. This suggested that lipid oxidation was occurred during RFT. With the increase of radical signal intensity, lower oxidation stability was presented by ESR. Raman intensity of ν(CC) stretching region (1655cm -1 ) was decreased during RFT. Furthermore, lower Raman intensity ratio of I 1655 /I 1442 , I 1655 /I 1745 that determine total unsaturation was also observed. Significant correlations (p<0.01) were obtained among conventional methods, ESR and Raman spectroscopy. Our result has proved that ESR and Raman spectroscopy showed great potential in characterizing lipid oxidation process of beef during RFT. Copyright © 2017 Elsevier Ltd. All rights reserved.

Resonant-enhanced spectroscopy of molecular rotations with a scanning tunneling microscope.

PubMed

Natterer, Fabian Donat; Patthey, François; Brune, Harald

2014-07-22

We use rotational excitation spectroscopy with a scanning tunneling microscope to investigate the rotational properties of molecular hydrogen and its isotopes physisorbed on the surfaces of graphene and hexagonal boron nitride (h-BN), grown on Ni(111), Ru(0001), and Rh(111). The rotational excitation energies are in good agreement with ΔJ = 2 transitions of freely spinning p-H2 and o-D2 molecules. The variations of the spectral line shapes for H2 among the different surfaces can be traced back to a molecular resonance-mediated tunneling mechanism. Our data for H2/h-BN/Rh(111) suggest a local intrinsic gating on this surface due to lateral static dipoles. Spectra on a mixed monolayer of H2, HD, and D2 display all three J = 0 → 2 rotational transitions, irrespective of tip position, thus pointing to a multimolecule excitation, or molecular mobility in the physisorbed close-packed layer.

Broadband stripline ferromagnetic resonance spectroscopy of ferromagnetic films, multilayers and nanostructures

NASA Astrophysics Data System (ADS)

Maksymov, Ivan S.; Kostylev, Mikhail

2015-05-01

This paper presents a comprehensive critical overview of fundamental and practical aspects of the modern stripline broadband ferromagnetic resonance (BFMR) spectroscopy largely employed for the characterisation of magnetic low-dimensional systems, such as thin ferro- and ferromagnetic, multiferroic and half-metallic films, multi-layers and nanostructures. These planar materials form the platform of the nascent fields of magnonics and spintronics. Experimental and theoretical results of research on these materials are summarised, along with systematic description of various phenomena associated with the peculiarities of the stripline BFMR, such as the geometry of stripline transducers, the orientation of the static magnetic field, the presence of microwave eddy currents, and the impacts of non-magnetic layers, interfaces and surfaces in the samples. Results from 240 articles, textbooks and technical reports are presented and many practical examples are discussed in detail. This review will be of interest to both general physical audience and specialists conducting research on various aspects of magnetisation dynamics and nanomagnetism.

Characterization of the pigment xanthomonadin in the bacterial genus Xanthomonas using micro- and resonance Raman spectroscopy

NASA Astrophysics Data System (ADS)

Paret, Mathews L.; Sharma, Shiv K.; Misra, Anupam K.; Acosta, Tayro; deSilva, Asoka S.; Vowell, Tomie; Alvarez, Anne M.

2012-06-01

We used micro- and resonance Raman spectroscopy with 785 nm and 514.5 nm laser excitation, respectively, to characterize a plant pathogenic bacteria, Xanthomonas axonopodis pv. dieffenbachiae D150. The bacterial genus Xathomonas is closely related to bacterial genus Stenotrophomonas that causes an infection in humans. This study has identified for the first time the unique Raman spectra of the carotenoid-like pigment xanthomonadin of the Xanthomonas strain. Xanthomonadin is a brominated aryl-polyene pigment molecule similar to carotenoids. Further studies were conducted using resonance Raman spectroscopy with 514.5 nm laser excitation on several strains of the bacterial genus Xanthomonas isolated from numerous plants from various geographical locations. The current study revealed that the Raman bands representing the vibrations (v1, v2, v3) of the polyene chain of xanthomonadin are 1003-1005 (v3), 1135-1138 (v2), and 1530 (v1). Overtone bands representing xanthomonadin were identified as 2264-2275 (2v2), and combinational bands at 2653-2662 (v1+ v2). The findings from this study validate our previous finding that the Raman fingerprints of xanthomonadin are unique for the genus Xanthomonas. This facilitates rapid identification (~5 minutes) of Xanthomonas spp. from bacterial culture plates. The xanthomonadin marker is different from Raman markers of many other bacterial genus including Agrobacterium, Bacillus, Clavibacter, Enterobacter, Erwinia, Microbacterium, Paenibacillus, and Ralstonia. This study also identified Xanthomonas spp. from bacterial strains isolated from a diseased wheat sample on a culture plate.

Advanced slow-magic angle spinning probe for magnetic resonance imaging and spectroscopy

DOEpatents

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

2006-01-24

The present invention relates to a probe and processes useful for magnetic resonance imaging and spectroscopy instruments. More particularly, the invention relates to a MR probe and processes for obtaining resolution enhancements of fluid objects, including live specimens, using an ultra-slow (magic angle) spinning (MAS) of the specimen combined with a modified phase-corrected magic angle turning (PHORMAT) pulse sequence. Proton NMR spectra were measured of the torso and the top part of the belly of a female BALBc mouse in a 2T field, while spinning the animal at a speed of 1.5 Hz. Results show that even in this relatively low field with PHORMAT, an isotropic spectrum is obtained with line widths that are a factor 4.6 smaller than those obtained in a stationary mouse. Resolution of ¹H NMR metabolite spectra are thus significantly enhanced. Results indicate that PHORMAT has the potential to significantly increase the utility of ¹H NMR spectroscopy for in vivo biochemical, biomedical and/or medical applications involving large-sized biological objects such as mice, rats and even humans within a hospital setting. For small-sized objects, including biological objects, such as excised tissues, organs, live bacterial cells, and biofilms, use of PASS at a spinning rate of 30 Hz and above is preferred.

Accelerated 2D magnetic resonance spectroscopy of single spins using matrix completion

NASA Astrophysics Data System (ADS)

Scheuer, Jochen; Stark, Alexander; Kost, Matthias; Plenio, Martin B.; Naydenov, Boris; Jelezko, Fedor

2015-12-01

Two dimensional nuclear magnetic resonance (NMR) spectroscopy is one of the major tools for analysing the chemical structure of organic molecules and proteins. Despite its power, this technique requires long measurement times, which, particularly in the recently emerging diamond based single molecule NMR, limits its application to stable samples. Here we demonstrate a method which allows to obtain the spectrum by collecting only a small fraction of the experimental data. Our method is based on matrix completion which can recover the full spectral information from randomly sampled data points. We confirm experimentally the applicability of this technique by performing two dimensional electron spin echo envelope modulation (ESEEM) experiments on a two spin system consisting of a single nitrogen vacancy (NV) centre in diamond coupled to a single 13C nuclear spin. The signal to noise ratio of the recovered 2D spectrum is compared to the Fourier transform of randomly subsampled data, where we observe a strong suppression of the noise when the matrix completion algorithm is applied. We show that the peaks in the spectrum can be obtained with only 10% of the total number of the data points. We believe that our results reported here can find an application in all types of two dimensional spectroscopy, as long as the measured matrices have a low rank.

Fourier Transform Infrared (FTIR) Spectroscopy, Ultraviolet Resonance Raman (UVRR) Spectroscopy, and Atomic Force Microscopy (AFM) for Study of the Kinetics of Formation and Structural Characterization of Tau Fibrils.

PubMed

Ramachandran, Gayathri

2017-01-01

Kinetic studies of tau fibril formation in vitro most commonly employ spectroscopic probes such as thioflavinT fluorescence and laser light scattering or negative stain transmission electron microscopy. Here, I describe the use of Fourier transform infrared (FTIR) spectroscopy, ultraviolet resonance Raman (UVRR) spectroscopy, and atomic force microscopy (AFM) as complementary probes for studies of tau aggregation. The sensitivity of vibrational spectroscopic techniques (FTIR and UVRR) to secondary structure content allows for measurement of conformational changes that occur when the intrinsically disordered protein tau transforms into cross-β-core containing fibrils. AFM imaging serves as a gentle probe of structures populated over the time course of tau fibrillization. Together, these assays help further elucidate the structural and mechanistic complexity inherent in tau fibril formation.

Electrostatic quadrupole focused particle accelerating assembly with laminar flow beam

DOEpatents

Maschke, A.W.

1984-04-16

A charged particle accelerating assembly provided with a predetermined ratio of parametric structural characteristics and with related operating voltages applied to each of its linearly spaced focusing and accelerating quadrupoles, thereby to maintain a particle beam traversing the electrostatic fields of the quadrupoles in the assembly in an essentially laminar flow through the assembly.

Electrostatic quadrupole focused particle accelerating assembly with laminar flow beam

DOEpatents

Maschke, Alfred W.

1985-01-01

A charged particle accelerating assembly provided with a predetermined ratio of parametric structural characteristics and with related operating voltages applied to each of its linearly spaced focusing and accelerating quadrupoles, thereby to maintain a particle beam traversing the electrostatic fields of the quadrupoles in the assembly in an essentially laminar flow throughout the assembly.

Neutral Pion Electroproduction in the Δ Resonance Region

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

Villano, Anthony

2007-11-01

The electroproduction of baryon resonances at high Q 2 is examined. Analysis focuses on the Δ(1232) resonance via exclusive pseudoscalar meson production of π 0 particles. Differential cross sections are extracted for exclusive π 0 electroproduction. In the central invariant mass (W) region the cross sections are used to extract resonant multipole amplitudes. In particular, the ratio of the electric quadrupole to magnetic dipole amplitudes (E2/M1) will be discussed for the Δ(1232) resonance. The transition to pQCD is discussed in terms of E2/M1 and other multipoles. The helicity amplitude A 3/2 can be used as a baryon helicity conservation meter in this context and will be discussed. The fast shrinking of the resonant contribution in the Δ region is observed at this high momentum transfer. Apart from the observables related to pQCD scaling, the transition form factor Gmore » $$*\\atop{M}$$ is extracted along with the scalar to magnetic dipole ratio C2/M1.« less

Application of nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, UV-Visible spectroscopy and kinetic modeling for elucidation of adsorption chemistry in uptake of tetracycline by zeolite beta.

PubMed

Kang, Jin; Liu, Huijuan; Zheng, Yu-Ming; Qu, Jiuhui; Chen, J Paul

2011-02-01

Extensive usage of tetracycline has resulted in its contamination in surface water and groundwater. The adsorption of tetracycline on zeolite beta was systematically investigated for the decontamination of the antibiotic polluted water in this study. Ninety percent of uptake by the zeolite beta occured in 0.25h, and the adsorption equilibrium was obtained within 3h, which was well described by an intraparticle diffusion model. The adsorption generally increased when pH was increased from 4.0 to 5.0, and then decreased significantly as the pH was further increased, which was caused by the pH-dependent speciation of tetracycline and surface charge of zeolite beta. Both Freundlich and Langmuir equations well described the adsorption isotherm. A thermodynamic analysis showed that the sorption process was spontaneous and endothermic. Aluminum atoms in the zeolite played a crucial role in the uptake; the adsorption increased with the increasing aluminum content in zeolite. The UV-Visible spectroscopy study showed that the spectra of tetracycline changed upon the interaction with zeolite beta, which could be ascribed to the formation of complexes of tetracycline and aluminum atoms in the zeolite surface. Nuclear magnetic resonance spectroscopy study further confirmed the participation of Al in the tetracycline adsorption. Fourier transform infrared spectroscopy studies showed that the amino functional groups in tetracycline were involved in the complexation with the zeolite surface. Copyright © 2010 Elsevier Inc. All rights reserved.

Investigation of hydrogenation of toluene to methylcyclohexane in a trickle bed reactor by low-field nuclear magnetic resonance spectroscopy.

PubMed

Guthausen, Gisela; von Garnier, Agnes; Reimert, Rainer

2009-10-01

Low-field nuclear magnetic resonance (NMR) spectroscopy is applied to study the hydrogenation of toluene in a lab-scale reactor. A conventional benchtop NMR system was modified to achieve chemical shift resolution. After an off-line validity check of the approach, the reaction product is analyzed on-line during the process, applying chemometric data processing. The conversion of toluene to methylcyclohexane is compared with off-line gas chromatographic analysis. Both classic analytical and chemometric data processing was applied. As the results, which are obtained within a few tens of seconds, are equivalent within the experimental accuracy of both methods, low-field NMR spectroscopy was shown to provide an analytical tool for reaction characterization and immediate feedback.

{open_quotes}Quadrupoled{close_quotes} materials for second-order nonlinear optics

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

Hubbard, S.F.; Petschek, R.G.; Singer, K.D.

1997-10-01

We describe a new approach to second-order nonlinear optical materials, namely quadrupoling. This approach is valid in the regime of Kleinman (full permutation) symmetry breaking, and thus requires a two- or three dimensional microscopic nonlinearity at wavelengths away from material resonances. This {open_quotes}quadrupolar{close_quotes} nonlinearity arises from the second rank pseudotensor of the rotationally invariant representation of the second-order nonlinear optical tensor. We have experimentally investigated candidate molecules comprised of chiral camphorquinone derivatives by measuring the scalar invariant associated with the rank two pseudotensor using hyper-Rayleigh scattering. We have found sizable scalar figures of merit for several compounds using light formore » which the second harmonic wavelengths are greater than 100 nm longer than the absorption peak location. At these wavelengths, the quadrupolar scalar is as large as the polar (EFISH) scalar of p-nitroaniline. Prospects for applications are discussed.« less

Fluorinated Paramagnetic Complexes: Sensitive and Responsive Probes for Magnetic Resonance Spectroscopy and Imaging

NASA Astrophysics Data System (ADS)

Peterson, Katie L.; Srivastava, Kriti; Pierre, Valérie C.

2018-05-01

Fluorine magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) of chemical and physiological processes is becoming more widespread. The strength of this technique comes from the negligible background signal in in vivo 19F MRI and the large chemical shift window of 19F that enables it to image concomitantly more than one marker. These same advantages have also been successfully exploited in the design of responsive 19F probes. Part of the recent growth of this technique can be attributed to novel designs of 19F probes with improved imaging parameters due to the incorporation of paramagnetic metal ions. In this review, we provide a description of the theories and strategies that have been employed successfully to improve the sensitivity of 19F probes with paramagnetic metal ions. The Bloch-Wangsness-Redfield theory accurately predicts how molecular parameters such as distance, geometry, rotational correlation times, as well as the nature, oxidation state, and spin state of the metal ion affect the sensitivity of the fluorine-based probes. The principles governing the design of responsive 19F probes are subsequently described in a “how to” guide format. Examples of such probes and their advantages and disadvantages are highlighted through a synopsis of the literature.

Chiral discrimination in nuclear magnetic resonance spectroscopy

NASA Astrophysics Data System (ADS)

Lazzeretti, Paolo

2017-11-01

Chirality is a fundamental property of molecules whose spatial symmetry is characterized by the absence of improper rotations, making them not superimposable to their mirror image. Chiral molecules constitute the elementary building blocks of living species and one enantiomer is favoured in general (e.g. L-aminoacids and D-sugars pervade terrestrial homochiral biochemistry) because most chemical reactions producing natural substances are enantioselective. Since the effect of chiral chemicals and drugs on living beings can be markedly different between enantiomers, the quest for practical spectroscopical methods to scrutinize chirality is an issue of great importance and interest. Nuclear magnetic resonance (NMR) is a topmost analytical technique, but spectrometers currently used are ‘blind’ to chirality, i.e. unable to discriminate the two mirror-image forms of a chiral molecule, because, in the absence of a chiral solvent, the spectral parameters, chemical shifts and spin-spin coupling constants are identical for enantiomers. Therefore, the development of new procedures for routine chiral recognition would offer basic support to scientists. However, in the presence of magnetic fields, a distinction between true and false chirality is mandatory. The former epitomizes natural optical activity, which is rationalized by a time-even pseudoscalar, i.e. the trace of a second-rank tensor, the mixed electric dipole/magnetic dipole polarizability. The Faraday effect, magnetic circular dichroism and magnetic optical activity are instead related to a time-odd axial vector. The present review summarizes recent theoretical and experimental efforts to discriminate enantiomers via NMR spectroscopy, with the focus on the deep connection between chirality and symmetry properties under the combined set of fundamental discrete operations, namely charge conjugation, parity (space inversion) and time (motion) reversal.

Targeted Proteomic Quantification on Quadrupole-Orbitrap Mass Spectrometer*

PubMed Central

Gallien, Sebastien; Duriez, Elodie; Crone, Catharina; Kellmann, Markus; Moehring, Thomas; Domon, Bruno

2012-01-01

There is an immediate need for improved methods to systematically and precisely quantify large sets of peptides in complex biological samples. To date protein quantification in biological samples has been routinely performed on triple quadrupole instruments operated in selected reaction monitoring mode (SRM), and two major challenges remain. Firstly, the number of peptides to be included in one survey experiment needs to be increased to routinely reach several hundreds, and secondly, the degree of selectivity should be improved so as to reliably discriminate the targeted analytes from background interferences. High resolution and accurate mass (HR/AM) analysis on the recently developed Q-Exactive mass spectrometer can potentially address these issues. This instrument presents a unique configuration: it is constituted of an orbitrap mass analyzer equipped with a quadrupole mass filter as the front-end for precursor ion mass selection. This configuration enables new quantitative methods based on HR/AM measurements, including targeted analysis in MS mode (single ion monitoring) and in MS/MS mode (parallel reaction monitoring). The ability of the quadrupole to select a restricted m/z range allows one to overcome the dynamic range limitations associated with trapping devices, and the MS/MS mode provides an additional stage of selectivity. When applied to targeted protein quantification in urine samples and benchmarked with the reference SRM technique, the quadrupole-orbitrap instrument exhibits similar or better performance in terms of selectivity, dynamic range, and sensitivity. This high performance is further enhanced by leveraging the multiplexing capability of the instrument to design novel acquisition methods and apply them to large targeted proteomic studies for the first time, as demonstrated on 770 tryptic yeast peptides analyzed in one 60-min experiment. The increased quality of quadrupole-orbitrap data has the potential to improve existing protein

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

PubMed

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

2012-12-01

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

Feshbach resonances in the exit channel of the F + CH3OH → HF + CH3O reaction observed using transition-state spectroscopy

NASA Astrophysics Data System (ADS)

Weichman, Marissa L.; Devine, Jessalyn A.; Babin, Mark C.; Li, Jun; Guo, Lifen; Ma, Jianyi; Guo, Hua; Neumark, Daniel M.

2017-10-01

The transition state governs how chemical bonds form and cleave during a chemical reaction and its direct characterization is a long-standing challenge in physical chemistry. Transition state spectroscopy experiments based on negative-ion photodetachment provide a direct probe of the vibrational structure and metastable resonances that are characteristic of the reactive surface. Dynamical resonances are extremely sensitive to the topography of the reactive surface and provide an exceptional point of comparison with theory. Here we study the seven-atom F + CH3OH → HF + CH3O reaction using slow photoelectron velocity-map imaging spectroscopy of cryocooled CH3OHF- anions. These measurements reveal spectral features associated with a manifold of vibrational Feshbach resonances and bound states supported by the post-transition state potential well. Quantum dynamical calculations yield excellent agreement with the experimental results, allow the assignment of spectral structure and demonstrate that the key dynamics of complex bimolecular reactions can be captured with a relatively simple theoretical framework.

Feshbach resonances in the exit channel of the F + CH3OH → HF + CH3O reaction observed using transition-state spectroscopy.

PubMed

Weichman, Marissa L; DeVine, Jessalyn A; Babin, Mark C; Li, Jun; Guo, Lifen; Ma, Jianyi; Guo, Hua; Neumark, Daniel M

2017-10-01

The transition state governs how chemical bonds form and cleave during a chemical reaction and its direct characterization is a long-standing challenge in physical chemistry. Transition state spectroscopy experiments based on negative-ion photodetachment provide a direct probe of the vibrational structure and metastable resonances that are characteristic of the reactive surface. Dynamical resonances are extremely sensitive to the topography of the reactive surface and provide an exceptional point of comparison with theory. Here we study the seven-atom F + CH 3 OH → HF + CH 3 O reaction using slow photoelectron velocity-map imaging spectroscopy of cryocooled CH 3 OHF - anions. These measurements reveal spectral features associated with a manifold of vibrational Feshbach resonances and bound states supported by the post-transition state potential well. Quantum dynamical calculations yield excellent agreement with the experimental results, allow the assignment of spectral structure and demonstrate that the key dynamics of complex bimolecular reactions can be captured with a relatively simple theoretical framework.

Method and apparatus for magnetic resonance imaging and spectroscopy using microstrip transmission line coils

DOEpatents

Zhang, Xiaoliang; Ugurbil, Kamil; Chen, Wei

2006-04-04

Apparatus and method for MRI imaging using a coil constructed of microstrip transmission line (MTL coil) are disclosed. In one method, a target is positioned to be imaged within the field of a main magnetic field of a magnet resonance imaging (MRI) system, a MTL coil is positioned proximate the target, and a MRI image is obtained using the main magnet and the MTL coil. In another embodiment, the MRI coil is used for spectroscopy. MRI imaging and spectroscopy coils are formed using microstrip transmission line. These MTL coils have the advantageous property of good performance while occupying a relatively small space, thus allowing MTL coils to be used inside restricted areas more easily than some other prior art coils. In addition, the MTL coils are relatively simple to construct of inexpensive components and thus relatively inexpensive compared to other designs. Further, the MTL coils of the present invention can be readily formed in a wide variety of coil configurations, and used in a wide variety of ways. Further, while the MTL coils of the present invention work well at high field strengths and frequencies, they also work at low frequencies and in low field strengths as well.

Transient Resonance Raman Spectroscopy of a Light-Driven Sodium-Ion-Pump Rhodopsin from Indibacter alkaliphilus.

PubMed

Kajimoto, Kousuke; Kikukawa, Takashi; Nakashima, Hiroki; Yamaryo, Haruki; Saito, Yuta; Fujisawa, Tomotsumi; Demura, Makoto; Unno, Masashi

2017-05-04

Sodium-ion-pump rhodopsin (NaR) is a microbial rhodopsin that transports Na + during its photocycle. Here we explore the photocycle mechanism of NaR from Indibacter alkaliphilus with transient absorption and transient resonance Raman spectroscopy. The transient absorption data indicate that the photocycle of NaR is K (545 nm) → L (490 nm)/M (420 nm) → O 1 (590 nm) → O 2 (560 nm) → NaR, where the L and M are formed as equilibrium states. The presence of K, L, M, and O intermediates was confirmed by the resonance Raman spectra with 442 and 532 nm excitation. The main component of the transient resonance Raman spectra was due to L which contains a 13-cis retinal protonated Schiff base. The presence of an enhanced hydrogen out-of-plane band as well as its sensitivity to the H/D exchange indicate that the retinal chromophore is distorted near the Schiff base region in L. Moreover, the retinal Schiff base of the L state forms a hydrogen bond that is stronger than that of the dark state. These observations are consistent with a Na + pumping mechanism that involves a proton transfer from the retinal Schiff base to a key aspartate residue (Asp116 in Krokinobacter eikastus rhodopsin 2) in the L/M states.

Soft X-ray absorption spectroscopy and resonant inelastic X-ray scattering spectroscopy below 100 eV: probing first-row transition-metal M-edges in chemical complexes.

PubMed

Wang, Hongxin; Young, Anthony T; Guo, Jinghua; Cramer, Stephen P; Friedrich, Stephan; Braun, Artur; Gu, Weiwei

2013-07-01

X-ray absorption and scattering spectroscopies involving the 3d transition-metal K- and L-edges have a long history in studying inorganic and bioinorganic molecules. However, there have been very few studies using the M-edges, which are below 100 eV. Synchrotron-based X-ray sources can have higher energy resolution at M-edges. M-edge X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS) could therefore provide complementary information to K- and L-edge spectroscopies. In this study, M2,3-edge XAS on several Co, Ni and Cu complexes are measured and their spectral information, such as chemical shifts and covalency effects, are analyzed and discussed. In addition, M2,3-edge RIXS on NiO, NiF2 and two other covalent complexes have been performed and different d-d transition patterns have been observed. Although still preliminary, this work on 3d metal complexes demonstrates the potential to use M-edge XAS and RIXS on more complicated 3d metal complexes in the future. The potential for using high-sensitivity and high-resolution superconducting tunnel junction X-ray detectors below 100 eV is also illustrated and discussed.

{sup 1}H NMR relaxometry and quadrupole relaxation enhancement as a sensitive probe of dynamical properties of solids—[C(NH{sub 2}){sub 3}]{sub 3}Bi{sub 2}I{sub 9} as an example

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

Florek-Wojciechowska, M.; Wojciechowski, M.; Brym, Sz.

{sup 1}H nuclear magnetic resonance relaxometry has been applied to reveal information on dynamics and structure of Gu{sub 3}Bi{sub 2}I{sub 9} ([Gu = C(NH{sub 2}){sub 3}] denotes guanidinium cation). The data have been analyzed in terms of a theory of quadrupole relaxation enhancement, which has been extended here by including effects associated with quadrupole ({sup 14}N) spin relaxation caused by a fast fluctuating component of the electric field gradient tensor. Two motional processes have been identified: a slow one occurring on a timescale of about 8 × 10{sup −6} s which has turned out to be (almost) temperature independent, andmore » a fast process in the range of 10{sup −9} s. From the {sup 1}H-{sup 14}N relaxation contribution (that shows “quadrupole peaks”) the quadrupole parameters, which are a fingerprint of the arrangement of the anionic network, have been determined. It has been demonstrated that the magnitude of the quadrupole coupling considerably changes with temperature and the changes are not caused by phase transitions. At the same time, it has been shown that there is no evidence of abrupt changes in the cationic dynamics and the anionic substructure upon the phase transitions.« less

Magnetic resonance imaging and magnetic resonance spectroscopy in a young male patient with anti-N-methyl-D-aspartate receptor encephalitis and uncommon cerebellar involvement: A case report with review of the literature

PubMed Central

Felli, Valentina; Di Sibio, Alessandra; Gennarelli, Antonio; Patriarca, Lucia; Stratta, Paolo; Di Cesare, Ernesto; Rossi, Alessandro; Massimo, Gallucci

2015-01-01

We report a case of a 17-year-old man presenting with new onset psychiatric symptoms. Magnetic resonance imaging (MRI) and proton magnetic resonance (MR) spectroscopy revealed some lesions in the right cerebellar hemisphere and ipsilateral cerebellar tonsil suggestive of encephalitis. An extensive workup was negative for both infectious and neoplastic diseases and he was afterward diagnosed with anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis. This disorder is an autoimmune encephalitis, highly lethal but curable, predominantly found in young female with ovarian teratoma. He received methylprednisolone. His clinical findings gradually improve and he made a complete recovery. Accordingly, repeated brain MRI and proton MR spectroscopy showed a gradual reduction of the lesions; MRI taken six months after starting therapy showed complete resolution of the lesions. Our case shows that, although rare, anti-NMDAR encephalitis should be considered also in young men for whom a rapid onset of psychiatric neurological disorders cannot be explained by more frequent causes. Our report underlines also the usefulness of MRI and proton MR spectroscopic findings in the diagnosis and follow-up of this disease. PMID:26613928

A Study of 2-Iodobutane by Rotational Spectroscopy

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

Arsenault, Eric A.; Obenchain, Daniel A.; Choi, Yoon Jeong

2016-09-15

The rotational transitions belonging to 2-iodobutane (sec-butyl-iodide, CH3CHICH2CH3) have been measured over the frequency range 5.5-16.5 GHz via jet-pulsed Fourier transform microwave (FTMW) spectroscopy. The complete nuclear quadrupole coupling tensor of iodine, ¬, has been obtained for the gauche (g)-, anti (a)-, and gauche0 (g0)-conformers, as well as the four 13C isotopologues of the gauche species. Rotational constants, centrifugal distortion constants, quadrupole coupling constants, and nuclear spin-rotation constants were determined for each species. Changes in the ¬ of the iodine nucleus, resulting from conformational and isotopic dierences, will be discussed. Isotopic substitution of g-2-iodobutane allowed for a rs structure tomore » be determined for the carbon backbone. Additionally, isotopic substitution, in conjunction with an ab initio structure, allowed for a t of various r0 structural parameters belonging to g-2-iodobutane.« less

Measurement of Electron Density Using the Multipole Resonance Probe, Langmuir Probe and Optical Emission Spectroscopy in Low Pressure Plasmas with Different Electron Energy Distribution Functions

NASA Astrophysics Data System (ADS)

Oberberg, Moritz; Bibinov, Nikita; Ries, Stefan; Awakowicz, Peter; Institute of Electrical Engineering; Plasma Technology Team

2016-09-01

In recently publication, the young diagnostic tool Multipole Resonance Probe (MRP) for electron density measurements was introduced. It is based on active plasma resonance spectroscopy (APRS). The probe was simulated und evaluated for different devices. The geometrical and electrical symmetry simplifies the APRS model, so that the electron density can be easily calculated from the measured resonance. In this work, low pressure nitrogen mixture plasmas with different electron energy distribution functions (EEDF) are investigated. The results of the MRP measurement are compared with measurements of a Langmuir Probe (LP) and Optical Emission Spectroscopy (OES). Probes and OES measure in different regimes of kinetic electron energy. Both probes measure electrons with low kinetic energy (<10 eV), whereas the OES is influenced by electrons with high kinetic energy which are needed for transitions of molecule bands. By the determination of the absolute intensity of N2(C-B) and N2+(B-X)electron temperature and density can be calculated. In a non-maxwellian plasma, all plasma diagnostics need to be combined.

Chemical structures of swine-manure chars produced under different carbonization conditions investigated by advanced solid-state 13C nuclear magnetic resonance (NMR) spectroscopy

USDA-ARS?s Scientific Manuscript database

Two types of swine manure chars, hydrothermally-produced hydrochar and slow-pyrolysis pyrochar, and their raw swine manure solid were characterized using advanced 13C solid-state nuclear magnetic resonance (NMR) spectroscopy. Compared with the parent raw swine manure, both hydrochars and pyrochar di...

Intracellular Phosphate Dynamics in Muscle Measured by Magnetic Resonance Spectroscopy during Hemodialysis

PubMed Central

Fournier, Thomas; Kocevar, Gabriel; Belloi, Amélie; Normand, Gabrielle; Ibarrola, Danielle; Sappey-Marinier, Dominique; Juillard, Laurent

2016-01-01

Of the 600–700 mg inorganic phosphate (Pi) removed during a 4-hour hemodialysis session, a maximum of 10% may be extracted from the extracellular space. The origin of the other 90% of removed phosphate is unknown. This study tested the hypothesis that the main source of phosphate removed during hemodialysis is the intracellular compartment. Six binephrectomized pigs each underwent one 3-hour hemodialysis session, during which the extracorporeal circulation blood flow was maintained between 100 and 150 ml/min. To determine in vivo phosphate metabolism, we performed phosphorous (31P) magnetic resonance spectroscopy using a 1.5-Tesla system and a surface coil placed over the gluteal muscle region. 31P magnetic resonance spectra (repetition time =10 s; echo time =0.35 ms) were acquired every 160 seconds before, during, and after dialysis. During the dialysis sessions, plasma phosphate concentrations decreased rapidly (−30.4 %; P=0.003) and then, plateaued before increasing approximately 30 minutes before the end of the sessions; 16 mmol phosphate was removed in each session. When extracellular phosphate levels plateaued, intracellular Pi content increased significantly (11%; P<0.001). Moreover, βATP decreased significantly (P<0.001); however, calcium levels remained balanced. Results of this study show that intracellular Pi is the source of Pi removed during dialysis. The intracellular Pi increase may reflect cellular stress induced by hemodialysis and/or strong intracellular phosphate regulation. PMID:26561642

Rotational Spectroscopy of the Low Energy Conformer of 2-METHYLBUTYRONITRILE and Search for it Toward Sagittarius B2(N2)

NASA Astrophysics Data System (ADS)

Müller, Holger S. P.; Wehres, Nadine; Zingsheim, Oliver; Lewen, Frank; Schlemmer, Stephan; Grabow, Jens-Uwe; Garrod, Robin T.; Belloche, Arnaud; Menten, Karl M.

2017-06-01

Quite recently, some of us detected iso-propyl cyanide as the first branched alkyl molecule in space. The identification was made in an ALMA Cycle 0 and 1 molecular line survey of Sagittarius B2(N) at 3 mm. The branched isomer was only slightly less abundant than its straight-chain isomer with a ratio of about 2:5. While initial chemical models favored the branched isomer somewhat, more recent models are able to reproduce the observed ratio. Moreover, the models predicted that among the next longer butyl cyanides (BuCNs) 2-methylbutyronitrile (2-MBN) should be more abundant than both n-BuCN and 3-MBN by factors of around 2, with t-BuCN being almost negligible. With the rotational spectra of t- and n-BuCN studied, we investigated those of 2-MBN and 3-MBN betwen ˜40 and ˜400 GHz by conventional absorption spectroscopy and by chirped-pulse and resonator Fourier transform microwave (FTMW) spectroscopy. The analyses were guided by quantum-chemical calculations. A. Belloche, R. T. Garrod, H. S. P. Müller, and K. M. Menten, Science 345 1584. R. T. Garrod, A. Belloche, H. S. P. Müller, and K. M. Menten, Astron. Astrophys., in press; doi: 10.1051/0004-6361/201630254. With the rotational spectra of t- and n-BuCN studied, we investigated those of 2-MBN and 3-MBN betwen ˜40 and ˜400 GHz by conventional absorption spectroscopy and by chirped-pulse and resonator Fourier transform microwave (FTMW) spectroscopy. The analyses were guided by quantum-chemical calculations. Here we report the analysis of the low-energy conformer of 2-MBN and a search for it in our current ALMA data. Two additional conformers are higher by ˜250 and ˜280 cm^{-1}. The low-energy conformer displays a very rich rotational spectrum because of its great asymmetry (κ ≈ 0.14) and large a- and b-dipole moment components. Accurate ^{14}N quadrupole coupling parameters were obtained from the FTMW spectral recordings.

Magnetic Resonance with Squeezed Microwaves

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

Bienfait, A.; Campagne-Ibarcq, P.; Kiilerich, A. H.

2017-10-17

Vacuum fluctuations of the electromagnetic field set a fundamental limit to the sensitivity of a variety of measurements, including magnetic resonance spectroscopy. We report the use of squeezed microwave fields, which are engineered quantum states of light for which fluctuations in one field quadrature are reduced below the vacuum level, to enhance the detection sensitivity of an ensemble of electronic spins at millikelvin temperatures. By shining a squeezed vacuum state on the input port of a microwave resonator containing the spins, we obtain a 1.2-dB noise reduction at the spectrometer output compared to the case of a vacuum input. Thismore » result constitutes a proof of principle of the application of quantum metrology to magnetic resonance spectroscopy.« less

Anterior cingulate cortex and cerebellar hemisphere neurometabolite changes in depression treatment: A 1H magnetic resonance spectroscopy study.

PubMed

Chen, Li-Ping; Dai, Hai-Yang; Dai, Zhuo-Zhi; Xu, Chong-Tao; Wu, Ren-Hua

2014-05-01

We utilized single-voxel 1H magnetic resonance spectroscopy to determine biochemical abnormalities related to major depressive disorder (MDD) in the bilateral dorsolateral prefrontal cortex, anterior cingulate cortex (ACC), and cerebellar hemisphere before and after antidepressant treatment. Fifteen adult MDD patients and 15 age- and sex-matched healthy controls were involved. Magnetic resonance spectroscopy of the brain was conducted in all subjects at the beginning of the study and the depressed subjects were reassessed after 8 weeks of antidepressant treatment. At baseline, N-acetyl aspartate (NAA), total glutamine plus glutamate (Glx) and myo-inositol (MI) levels in the bilateral ACC were significantly lower in MDD patients than in controls (P < 0.05/3). MI in the bilateral cerebellar hemisphere were also decreased in patients compared with controls. After the treatment, the lower NAA, Glx and MI in ACC were normalized in MDD patients and the NAA and Glx increased compared to baseline values. The MI levels in the bilateral cerebellar hemisphere were also normalized in patients. MI and choline levels in the right cerebellar hemisphere were elevated compared to those at baseline. Our study suggests that metabolic abnormalities in the ACC and cerebellar hemisphere are implicated in MDD. Antidepressants may alter the local metabolic abnormalities in these areas. © 2014 The Authors. Psychiatry and Clinical Neurosciences © 2014 Japanese Society of Psychiatry and Neurology.

Conformational Structure of Tyrosine, Tyrosyl-Glycine, and Tyrosyl-Glycyl-Glycine by Double Resonance Spectroscopy

NASA Technical Reports Server (NTRS)

Abo-Riziq, Ali; Grace, Louis; Crews, Bridgit; Callahan, Michael P,; van Mourik, Tanja; de Vries, Mattanjah S,

2011-01-01

We investigated the variation in conformation for the amino acid tyrosine (Y), alone and in the small peptides tyrosine-glycine (YC) and tyrosine-glycine-glycine (YGG), in the gas phase by using UV-UV and IR-UV double resonance spectroscopy and density functional theory calculations. For tyrosine we found seven different conformations, for YG we found four different conformations, and for YGG we found three different conformations. As the peptides get larger, we observe fewer stable conformers, despite the increasing complexity and number of degrees of freedom. We find structural trends similar to those in phenylalanine-glycine glycine (FGG) and tryptophan-glycine-glycine (WGG)j however) the effect of dispersive forces in FGG for stabilizing a folded structure is replaced by that of hydrogen bonding in YGG.

31P-nuclear magnetic resonance spectroscopy in vivo of six human melanoma xenograft lines: tumour bioenergetic status and blood supply.

PubMed Central

Lyng, H.; Olsen, D. R.; Southon, T. E.; Rofstad, E. K.

1993-01-01

Six human melanoma xenograft lines grown s.c. in BALB/c-nu/nu mice were subjected to 31P-nuclear magnetic resonance (31P-NMR) spectroscopy in vivo. The following resonances were detected: phosphomonoesters (PME), inorganic phosphate (Pi), phosphodiesters (PDE), phosphocreatine (PCr) and nucleoside triphosphate gamma, alpha and beta (NTP gamma, alpha and beta). The main purpose of the work was to search for possible relationships between 31P-NMR resonance ratios and tumour pH on the one hand and blood supply per viable tumour cell on the other. The latter parameter was measured by using the 86Rb uptake method. Tumour bioenergetic status [the (PCr + NTP beta)/Pi resonance ratio], tumour pH and blood supply per viable tumour cell decreased with increasing tumour volume for five of the six xenograft lines. The decrease in tumour bioenergetic status was due to a decrease in the (PCr + NTP beta)/total resonance ratio as well as an increase in the Pi/total resonance ratio. The decrease in the (PCr + NTP beta)/total resonance ratio was mainly a consequence of a decrease in the PCr/total resonance ratio for two lines and mainly a consequence of a decrease in the NTP beta/total resonance ratio for three lines. The magnitude of the decrease in the (PCr + NTP beta)/total resonance ratio and the magnitude of the decrease in tumour pH were correlated to the magnitude of the decrease in blood supply per viable tumour cell. Tumour pH decreased with decreasing tumour bioenergetic status, and the magnitude of this decrease was larger for the tumour lines showing a high than for those showing a low blood supply per viable tumour cell. No correlations across the tumour lines were found between tumour pH and tumour bioenergetic status or any other resonance ratio on the one hand and blood supply per viable tumour cell on the other. The differences in the 31P-NMR spectrum between the tumour lines were probably caused by differences in the intrinsic biochemical properties of the tumour

Qualitative analysis of the stability of the oxazine ring of various benzoxazine and pyridooxazine derivatives with proton nuclear magnetic resonance spectroscopy.

PubMed

Moloney, G P; Craik, D J; Iskander, M N

1992-07-01

A series of 3,4-dihydro-1,3-benzoxazine and 3,4-dihydro-1,3-pyridooxazine derivatives was synthesized, and the hydrolysis of the derivatives was studied with proton nuclear magnetic resonance spectroscopy. The oxazine derivatives underwent various degrees of hydrolysis when H2O was added to dimethyl sulfoxide solutions of the compounds. The rates and extents of decomposition of the oxazine ring systems depended on the electronic effects of substituents within the molecules. Examination of the proton nuclear magnetic resonance spectra that were generated during decomposition of the oxazines and trends in stability of the oxazine derivatives suggest the formation of an intermediate in the hydrolysis mechanism.

UV-resonance Raman spectroscopy of amino acids

NASA Astrophysics Data System (ADS)

Höhl, Martin; Meinhardt-Wollweber, Merve; Schmitt, Heike; Lenarz, Thomas; Morgner, Uwe

2016-03-01

Resonant enhancement of Raman signals is a useful method to increase sensitivity in samples with low concentration such as biological tissue. The investigation of resonance profiles shows the optimal excitation wavelength and yields valuable information about the molecules themselves. However careful characterization and calibration of all experimental parameters affecting quantum yield is required in order to achieve comparability of the single spectra recorded. We present an experimental technique for measuring the resonance profiles of different amino acids. The absorption lines of these molecules are located in the ultraviolet (UV) wavelength range. One limitation for broadband measurement of resonance profiles is the limited availability of Raman filters in certain regions of the UV for blocking the Rayleigh scattered light. Here, a wavelength range from 244.8 nm to 266.0 nm was chosen. The profiles reveal the optimal wavelength for recording the Raman spectra of amino acids in aqueous solutions in this range. This study provides the basis for measurements on more complex molecules such as proteins in the human perilymph. The composition of this liquid in the inner ear is essential for hearing and cannot be analyzed non-invasively so far. The long term aim is to implement this technique as a fiber based endoscope for non-invasive measurements during surgeries (e. g. cochlear implants) making it available as a diagnostic tool for physicians. This project is embedded in the interdisciplinary cluster of excellence "Hearing for all" (H4A).

Resonance ionization for analytical spectroscopy

DOEpatents

Hurst, George S.; Payne, Marvin G.; Wagner, Edward B.

1976-01-01

This invention relates to a method for the sensitive and selective analysis of an atomic or molecular component of a gas. According to this method, the desired neutral component is ionized by one or more resonance photon absorptions, and the resultant ions are measured in a sensitive counter. Numerous energy pathways are described for accomplishing the ionization including the use of one or two tunable pulsed dye lasers.

Method of using a nuclear magnetic resonance spectroscopy standard

DOEpatents

Spicer, Leonard D.; Bennett, Dennis W.; Davis, Jon F.

1985-01-01

(CH.sub.3).sub.3 SiNSO is produced by the reaction of ((CH.sub.3).sub.3 Si).sub.2 NH with SO.sub.2. Also produced in the reaction are ((CH.sub.3).sub.3 Si).sub.2 O and a new solid compound [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ]. Both (CH.sub.3).sub.3 SiNSO and [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ] have fluorescent properties. The reaction of the subject invention is used in a method of measuring the concentration of SO.sub.2 pollutants in gases. By the method, a sample of gas is bubbled through a solution of ((CH.sub.3).sub.3 Si).sub.2 NH, whereby any SO.sub.2 present in the gas will react to produce the two fluorescent products. The measured fluorescence of these products can then be used to calculate the concentration of SO.sub.2 in the original gas sample. The solid product [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ] may be used as a standard in solid state NMR spectroscopy, wherein the resonance peaks of either .sup.1 H, .sup.13 C, .sup.15 N, or .sup.29 Si may be used as a reference.

Circulating blood volume determination using electronic spin resonance spectroscopy.

PubMed

Facorro, Graciela; Bianchin, Ana; Boccio, José; Hager, Alfredo

2006-09-01

There have been numerous methods proposed to measure the circulating blood volume (CBV). Nevertheless, none of them have been massively and routinely accepted in clinical diagnosis. This study describes a simple and rapid method, on a rabbit model, using the dilution of autologous red cells labeled with a nitroxide radical (Iodoacetamide-TEMPO), which can be detected by electronic spin resonance (ESR) spectroscopy. Blood samples were withdrawn and re-injected using the ears' marginal veins. The average CBV measured by the new method/body weight (CBV(IAT)/BW) was 59 +/- 7 mL/kg (n = 33). Simultaneously, blood volume determinations using the nitroxide radical and (51)Cr (CBV(Cr)) were performed. In the plot of the difference between the methods (CBV(IAT) - CBV(Cr)) against the average (CBV(IAT) + CBV(Cr))/2, the mean of the bias was -1.1 +/- 6.9 mL and the limits of agreement (mean difference +/-2 SD) were -14.9 and 12.7 mL. Lin's concordance correlation coefficient p(c) = 0.988. Thus, both methods are in close agreement. The development of a new method that allows a correct estimation of the CBV without using radioactivity, avoiding blood manipulation, and decreasing the possibility of blood contamination with similar accuracy and precision of that of the "gold standard method" is an innovative proposal.

Coherent pump pulses in Double Electron Electron Resonance Spectroscopy

PubMed Central

Tait, Claudia E.; Stoll, Stefan

2016-01-01

The recent introduction of shaped pulses to Double Electron Electron Resonance (DEER) spectroscopy has led to significant enhancements in sensitivity through increased excitation bandwidths and improved control over spin dynamics. The application of DEER has so far relied on the presence of an incoherent pump channel to average out most undesired coherent effects of the pump pulse(s) on the observer spins. However, in fully coherent EPR spectrometers that are increasingly used to generate shaped pulses, the presence of coherent pump pulses means that these effects need to be explicitly considered. In this paper, we examine the effects of coherent rectangular and sech/tanh pump pulses in DEER experiments with up to three pump pulses. We show that, even in the absence of significant overlap of the observer and pump pulse excitation bandwidths, coherence transfer pathways involving both types of pulses generate spin echoes of considerable intensity. These echoes introduce artefacts, which, if not identified and removed, can easily lead to misinterpretation. We demonstrate that the observed echoes can be quantitatively modelled using a simple spin quantum dynamics approach that includes instrumental transfer functions. Based on an analysis of the echo crossing artefacts, we propose efficient phase cycling schemes for their suppression. This enables the use of advanced DEER experiments, characterized by high sensitivity and increased accuracy for long-distance measurements, on novel fully coherent EPR spectrometers. PMID:27339858

Aharonov–Anandan quantum phases and Landau quantization associated with a magnetic quadrupole moment

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

Fonseca, I.C.; Bakke, K., E-mail: kbakke@fisica.ufpb.br

The arising of geometric quantum phases in the wave function of a moving particle possessing a magnetic quadrupole moment is investigated. It is shown that an Aharonov–Anandan quantum phase (Aharonov and Anandan, 1987) can be obtained in the quantum dynamics of a moving particle with a magnetic quadrupole moment. In particular, it is obtained as an analogue of the scalar Aharonov–Bohm effect for a neutral particle (Anandan, 1989). Besides, by confining the quantum particle to a hard-wall confining potential, the dependence of the energy levels on the geometric quantum phase is discussed and, as a consequence, persistent currents can arisemore » from this dependence. Finally, an analogue of the Landau quantization is discussed. -- Highlights: •Scalar Aharonov–Bohm effect for a particle possessing a magnetic quadrupole moment. •Aharonov–Anandan quantum phase for a particle with a magnetic quadrupole moment. •Dependence of the energy levels on the Aharonov–Anandan quantum phase. •Landau quantization associated with a particle possessing a magnetic quadrupole moment.« less

Development of a high-sensitivity and portable cell using Helmholtz resonance for noninvasive blood glucose-level measurement based on photoacoustic spectroscopy.

PubMed

Tachibana, K; Okada, K; Kobayashi, R; Ishihara, Y

2016-08-01

We describe the possibility of high-sensitivity noninvasive blood glucose measurement based on photoacoustic spectroscopy (PAS). The demand for noninvasive blood glucose-level measurement has increased due to the explosive increase in diabetic patients. We have developed a noninvasive blood glucose-level measurement based on PAS. The conventional method uses a straight-type resonant cell. However, the cell volume is large, which results in a low detection sensitivity and difficult portability. In this paper, a small-sized Helmholtz-type resonant cell is proposed to improve detection sensitivity and portability by reducing the cell dead volume. First, the acoustic property of the small-sized Helmholtz-type resonant cell was evaluated by performing an experiment using a silicone rubber. As a result, the detection sensitivity of the small-sized Helmholtz-type resonant cell was approximately two times larger than that of the conventional straight-type resonant cell. In addition, the inside volume was approximately 30 times smaller. Second, the detection limits of glucose concentration were estimated by performing an experiment using glucose solutions. The experimental results showed that a glucose concentration of approximately 1% was detected by the small-sized Helmholtz-type resonant cell. Although these results on the sensitivity of blood glucose-level measurement are currently insufficient, they suggest that miniaturization of a resonance cell is effective in the application of noninvasive blood glucose-level measurement.

A modified quadrupole mass spectrometer with custom RF link rods driver for remote operation

NASA Technical Reports Server (NTRS)

Tashbar, P. W.; Nisen, D. B.; Moore, W. W., Jr.

1973-01-01

A commercial quadrupole residual gas analyzer system has been upgraded for operation at extended cable lengths. Operation inside a vacuum chamber for the standard quadrupole nude head is limited to approximately 2 m from its externally located rf/dc generator because of the detuning of the rf oscillator circuits by the coaxial cable reactance. The advance of long distance remote operation inside a vacuum chamber for distances of 45 and 60 m was made possible without altering the quadrupole's rf/dc generator circuit by employing an rf link to drive the quadrupole rods. Applications of the system have been accomplished for in situ space simulation thermal/vacuum testing of sophisticated payloads.

Magnetic resonance spectroscopy for detection of choline kinase inhibition in the treatment of brain tumors

PubMed Central

Kumar, Manoj; Arlauckas, Sean P.; Saksena, Sona; Verma, Gaurav; Ittyerah, Ranjit; Pickup, Stephen; Popov, Anatoliy V.; Delikatny, Edward J.; Poptani, Harish

2015-01-01

Abnormal choline metabolism is a hallmark of cancer and is associated with oncogenesis and tumor progression. Increased choline is consistently observed in both pre-clinical tumor models and in human brain tumors by proton magnetic resonance spectroscopy (MRS). Thus, inhibition of choline metabolism using specific choline kinase inhibitors such as MN58b may be a promising new strategy for treatment of brain tumors. We demonstrate the efficacy of MN58b in suppressing phosphocholine production in three brain tumor cell lines. In vivo MRS studies of rats with intra-cranial F98-derived brain tumors showed a significant decrease in tumor total choline concentration after treatment with MN58b. High resolution MRS of tissue extracts confirmed that this decrease was due to a significant reduction in phosphocholine. Concomitantly, a significant increase in poly-unsaturated lipid resonances was also observed in treated tumors, indicating apoptotic cell death. Magnetic resonance imaging (MRI) based volume measurements demonstrated a significant growth arrest in the MN58b-treated tumors in comparison to saline-treated controls. Histologically, MN58b-treated tumors showed decreased cell density, as well as increased apoptotic cells. These results suggest that inhibition of choline kinase can be used as an adjuvant to chemotherapy in the treatment of brain tumors and that decreases in total choline observed by MRS can be used as an effective phamacodynamic biomarker of treatment response. PMID:25657334

LARP Long Quadrupole: A "Long" Step Toward an LHC

ScienceCinema

Giorgio Ambrosio

2017-12-09

The beginning of the development of Nb3Sn magnets for particle accelerators goes back to the 1960’s. But only very recently has this development begun to face the challenges of fabricating Nb3Sn magnets which can meet the requirements of modern particle accelerators. LARP (the LHC Accelerator Research Program) is leading this effort focusing on long models of the Interaction Region quadrupoles for a possible luminosity upgrade of the Large Hadron Collider. A major milestone in this development is to test, by the end of 2009, 4m-long quadrupole models, which will be the first Nb3Sn accelerator-type magnets approaching the length of real accelerator magnets. The Long Quadrupoles (LQ) are “Proof-of-Principle” magnets which are to demonstrate that Nb3Sn technology is sufficiently mature for use in high energy particle accelerators. Their design is based on the LARP Technological Quadrupole (TQ) models, under development at FNAL and LBNL, which have design gradients higher than 200 T/m and an aperture of 90 mm. Several challenges must be addressed for the successful fabrication of long Nb3Sn coils and magnets. These challenges and the solutions adopted will be presented together with the main features of the LQ magnets. Several R&D lines are participating to this effort and their contributions will be also presented.

Sensitivity enhancement by chromatographic peak concentration with ultra-high performance liquid chromatography-nuclear magnetic resonance spectroscopy for minor impurity analysis.

PubMed

Tokunaga, Takashi; Akagi, Ken-Ichi; Okamoto, Masahiko

2017-07-28

High performance liquid chromatography can be coupled with nuclear magnetic resonance (NMR) spectroscopy to give a powerful analytical method known as liquid chromatography-nuclear magnetic resonance (LC-NMR) spectroscopy, which can be used to determine the chemical structures of the components of complex mixtures. However, intrinsic limitations in the sensitivity of NMR spectroscopy have restricted the scope of this procedure, and resolving these limitations remains a critical problem for analysis. In this study, we coupled ultra-high performance liquid chromatography (UHPLC) with NMR to give a simple and versatile analytical method with higher sensitivity than conventional LC-NMR. UHPLC separation enabled the concentration of individual peaks to give a volume similar to that of the NMR flow cell, thereby maximizing the sensitivity to the theoretical upper limit. The UHPLC concentration of compound peaks present at typical impurity levels (5.0-13.1 nmol) in a mixture led to at most three-fold increase in the signal-to-noise ratio compared with LC-NMR. Furthermore, we demonstrated the use of UHPLC-NMR for obtaining structural information of a minor impurity in a reaction mixture in actual laboratory-scale development of a synthetic process. Using UHPLC-NMR, the experimental run times for chromatography and NMR were greatly reduced compared with LC-NMR. UHPLC-NMR successfully overcomes the difficulties associated with analyses of minor components in a complex mixture by LC-NMR, which are problematic even when an ultra-high field magnet and cryogenic probe are used. Copyright © 2017 Elsevier B.V. All rights reserved.

Ellipsoidal universe can solve the cosmic microwave background quadrupole problem.

PubMed

Campanelli, L; Cea, P; Tedesco, L

2006-09-29

The recent 3 yr Wilkinson Microwave Anisotropy Probe data have confirmed the anomaly concerning the low quadrupole amplitude compared to the best-fit Lambda-cold dark matter prediction. We show that by allowing the large-scale spatial geometry of our universe to be plane symmetric with eccentricity at decoupling or order 10(-2), the quadrupole amplitude can be drastically reduced without affecting higher multipoles of the angular power spectrum of the temperature anisotropy.

Influence of resonant collisions on the self-broadening of acetylene

NASA Astrophysics Data System (ADS)

Lehmann, Kevin K.

2017-03-01

Iwakuni et al. [Phys. Rev. Lett. 117, 143902 (2016)] have reported an ortho-para alternation of ˜10% in the self pressure broadening coefficients for ro-vibrational lines of the C2H2 transitions in the ν1+ν3 C-H (local mode) overtone band near 197 THz (1.52 μm). These authors attributed this effect to the contribution of resonant collisions, where the rotational energy change of one molecule is exactly compensated by the rotational energy change of its collision partner. Resonant collisions are known to be important in the case of self pressure broadening of highly polar molecules, such as HCN, but have not previously been invoked in the case of nonpolar molecules, such as acetylene, where the long range potential is dominated by the quadrupole-quadrupole electrostatic interaction. In the present work, the simple semiclassical Anderson-theory approach is used to estimate the rates of C2H2-C2H2 rotationally inelastic collisions and these used to predict pressure broadening rates, ignoring other contributions to the broadening, which should not have resonant enhancements. It is found that exactly resonant collisions do not make a major contribution to the broadening and these calculations predict an ortho-para alternation of the pressure broadening coefficients far below what was inferred by Iwakuni et al. The present results are consistent with a large body of published work that reported self-broadening coefficients of C2H2 ro-vibrational transitions that found negligible dependence on the vibrational transition and no even-odd alternation, even for Q and S branch transitions where any such effect is predicted to be much larger than for the P and R branch transitions studied by Iwakuni et al.

Role of pyruvate dehydrogenase inhibition in the development of hypertrophy in the hyperthyroid rat heart: a combined magnetic resonance imaging and hyperpolarized magnetic resonance spectroscopy study.

PubMed

Atherton, Helen J; Dodd, Michael S; Heather, Lisa C; Schroeder, Marie A; Griffin, Julian L; Radda, George K; Clarke, Kieran; Tyler, Damian J

2011-06-07

Hyperthyroidism increases heart rate, contractility, cardiac output, and metabolic rate. It is also accompanied by alterations in the regulation of cardiac substrate use. Specifically, hyperthyroidism increases the ex vivo activity of pyruvate dehydrogenase kinase, thereby inhibiting glucose oxidation via pyruvate dehydrogenase. Cardiac hypertrophy is another effect of hyperthyroidism, with an increase in the abundance of mitochondria. Although the hypertrophy is initially beneficial, it can eventually lead to heart failure. The aim of this study was to use hyperpolarized magnetic resonance spectroscopy to investigate the rate and regulation of in vivo pyruvate dehydrogenase flux in the hyperthyroid heart and to establish whether modulation of flux through pyruvate dehydrogenase would alter cardiac hypertrophy. Hyperthyroidism was induced in 18 male Wistar rats with 7 daily intraperitoneal injections of freshly prepared triiodothyronine (0.2 mg x kg(-1) x d(-1)). In vivo pyruvate dehydrogenase flux, assessed with hyperpolarized magnetic resonance spectroscopy, was reduced by 59% in hyperthyroid animals (0.0022 ± 0.0002 versus 0.0055 ± 0.0005 second(-1); P=0.0003), and this reduction was completely reversed by both short- and long-term delivery of dichloroacetic acid, a pyruvate dehydrogenase kinase inhibitor. Hyperpolarized [2-(13)C]pyruvate was also used to evaluate Krebs cycle metabolism and demonstrated a unique marker of anaplerosis, the level of which was significantly increased in the hyperthyroid heart. Cine magnetic resonance imaging showed that long-term dichloroacetic acid treatment significantly reduced the hypertrophy observed in hyperthyroid animals (100 ± 20 versus 200 ± 30 mg; P=0.04) despite no change in the increase observed in cardiac output. This work has demonstrated that inhibition of glucose oxidation in the hyperthyroid heart in vivo is mediated by pyruvate dehydrogenase kinase. Relieving this inhibition can increase the metabolic

Time differentiated nuclear resonance spectroscopy coupled with pulsed laser heating in diamond anvil cells

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

Kupenko, I., E-mail: kupenko@esrf.fr; Strohm, C.; ESRF-The European Synchrotron, CS 40220, 38043 Grenoble Cedex 9

2015-11-15

Developments in pulsed laser heating applied to nuclear resonance techniques are presented together with their applications to studies of geophysically relevant materials. Continuous laser heating in diamond anvil cells is a widely used method to generate extreme temperatures at static high pressure conditions in order to study the structure and properties of materials found in deep planetary interiors. The pulsed laser heating technique has advantages over continuous heating, including prevention of the spreading of heated sample and/or the pressure medium and, thus, a better stability of the heating process. Time differentiated data acquisition coupled with pulsed laser heating in diamondmore » anvil cells was successfully tested at the Nuclear Resonance beamline (ID18) of the European Synchrotron Radiation Facility. We show examples applying the method to investigation of an assemblage containing ε-Fe, FeO, and Fe{sub 3}C using synchrotron Mössbauer source spectroscopy, FeCO{sub 3} using nuclear inelastic scattering, and Fe{sub 2}O{sub 3} using nuclear forward scattering. These examples demonstrate the applicability of pulsed laser heating in diamond anvil cells to spectroscopic techniques with long data acquisition times, because it enables stable pulsed heating with data collection at specific time intervals that are synchronized with laser pulses.« less

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

NASA Astrophysics Data System (ADS)

Elywa, M.

2015-07-01

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

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

PubMed Central

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

2015-01-01

A dual-nuclei radiofrequency coil array was constructed for phosphorus and proton magnetic resonance imaging and spectroscopy of the human brain at 7 Tesla. An eight-channel transceive degenerate birdcage phosphorus module was implemented to provide whole-brain coverage and significant sensitivity improvement over a standard dual-tuned loop coil. A nested eight-channel proton module provided adequate sensitivity for anatomical localization without substantially sacrificing performance on the phosphorus module. The developed array enabled phosphorus spectroscopy, a saturation transfer technique to calculate the global creatine kinase forward reaction rate, and single-metabolite whole-brain imaging with 1.4 cm nominal isotropic resolution in 15 min (2.3 cm actual resolution), while additionally enabling 1 mm isotropic proton imaging. This study demonstrates that a multi-channel array can be utilized for phosphorus and proton applications with improved coverage and/or sensitivity over traditional single-channel coils. The efficient multi-channel coil array, time-efficient pulse sequences, and the enhanced signal strength available at ultra-high fields can be combined to allow volumetric assessment of the brain and could provide new insights into the underlying energy metabolism impairment in several neurodegenerative conditions, such as Alzheimer’s and Parkinson’s diseases, as well as mental disorders such as schizophrenia. PMID:26375209

Detection of organic free radicals in irradiated Foeniculi fructus by electron spin resonance spectroscopy.

PubMed

Yamaoki, Rumi; Tsujino, Toshiaki; Kimura, Shojiro; Mino, Yoshiki; Ohta, Masatoshi

2009-01-01

Foeniculi fructus were irradiated with an electron beam and organic free radicals were detected by electron spin resonance (ESR) spectroscopy for the purpose of identifying radio-disinfected and sterilized herbal drugs. An ESR single-line spectrum near g = 2.005 was observed in the sample before irradiation. After irradiation, the intensity of the signal near g = 2.005 increased. In addition, two subsignals derived from cellulose radicals were observed approximately 3 mT to either side of the main signal, at g = 2.023 and g = 1.987. The intensity of the subsignal at g = 2.023 was proportional to the absorbed dose of radiation. The decrease in intensity of the signals was considerable 2 weeks after irradiation, and continued to decrease steadily thereafter. Among the signals, the fading of the subsignal at g = 2.023 was relatively small. The intensity of the subsignal at g = 2.023 was detectable for over 1 year in the sample that had been irradiated to the level of disinfection and sterilization. Therefore, organic free radicals in irradiated Foeniculi fructus can be measured rapidly and with high sensitivity by ESR spectroscopy. The stable signal at g = 2.023 is a promising indicator of the detection of irradiated herbal drugs.

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

PubMed

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

2016-01-01

A dual-nuclei radiofrequency coil array was constructed for phosphorus and proton magnetic resonance imaging and spectroscopy of the human brain at 7T. An eight-channel transceive degenerate birdcage phosphorus module was implemented to provide whole-brain coverage and significant sensitivity improvement over a standard dual-tuned loop coil. A nested eight-channel proton module provided adequate sensitivity for anatomical localization without substantially sacrificing performance on the phosphorus module. The developed array enabled phosphorus spectroscopy, a saturation transfer technique to calculate the global creatine kinase forward reaction rate, and single-metabolite whole-brain imaging with 1.4cm nominal isotropic resolution in 15min (2.3cm actual resolution), while additionally enabling 1mm isotropic proton imaging. This study demonstrates that a multi-channel array can be utilized for phosphorus and proton applications with improved coverage and/or sensitivity over traditional single-channel coils. The efficient multi-channel coil array, time-efficient pulse sequences, and the enhanced signal strength available at ultra-high fields can be combined to allow volumetric assessment of the brain and could provide new insights into the underlying energy metabolism impairment in several neurodegenerative conditions, such as Alzheimer's and Parkinson's diseases, as well as mental disorders such as schizophrenia. Copyright © 2015 Elsevier Inc. All rights reserved.

Shifts due to quantum-mechanical interference from distant neighboring resonances for saturated fluorescence spectroscopy of the 23S to 23P intervals of helium

NASA Astrophysics Data System (ADS)

Marsman, A.; Hessels, E. A.; Horbatsch, M.

2014-04-01

Quantum-mechanical interference with distant neighboring resonances is found to cause shifts for precision saturated fluorescence spectroscopy of the atomic helium 23S-to-23P transitions. The shifts are significant (larger than the experimental uncertainties for measurements of the intervals) despite the fact that the neighboring resonances are separated from the measured resonances by 1400 and 20000 natural widths. The shifts depend strongly on experimental parameters such as the angular position of the fluorescence detector, the intensity and size of laser beams, and the properties of the atomic beam. These shifts must be considered for the ongoing program of determining the fine-structure constant from the helium 23P fine structure.

MRI and (31)P magnetic resonance spectroscopy hardware for axillary lymph node investigation at 7T.

PubMed

Rivera, Debra S; Wijnen, Jannie P; van der Kemp, Wybe J M; Raaijmakers, Alexander J; Luijten, Peter R; Klomp, Dennis W J

2015-05-01

Neoadjuvant treatment response in lymph nodes predicts patient outcome, but existing methods do not track response during therapy accurately. In this study, specialized hardware was used to adapt high-field (7T) (31) P magnetic resonance spectroscopy (MRS), which has been shown to track treatment response in small breast tumors, to monitor axillary lymph nodes. A dual-tuned quadrature coil that is a (31) P (120 MHz) transceiver and a (1) H (300 MHz) receiver was designed using a novel detune circuit. The transceiver/receiver coil in the axilla is used with a fractionated dipole antenna on the back of the subject and the conventional breast coil for transmit. The novel circuit detuned the (1) H resonance without disturbing the (31) P resonance. In vivo demonstrations included: >80% homogeneous B1 (+) for (1) H over the axilla, identification of a small (3-mm diameter) lymph node, and (31) P MR spectra from a single healthy lymph node. The setup can detect <2 millimolar concentrations of metabolites from a 2-mL voxel. The first (31) P MR spectrum from an in vivo lymph node indicates that the presented design may be sufficiently sensitive to detect metabolic response to neoadjuvant therapy. Multinuclei MRS of the lymph nodes at 7T is possible through combining lightweight antenna elements with dual-tuned transceiver/receive-only coils. © 2014 Wiley Periodicals, Inc.

Quadrupole and octupole shapes in nuclei

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

Cline, D.

1993-12-31

The heavy-ion multiple Coulomb excitation technique, which has benefited from many important contributions by Dick Diamond, has developed to the stage where rather complete sets of E1, E2 and E3 matrix elements are being measured. These provide a sensitive measures of quadrupole and octupole deformation in nuclei. The completeness of the E2 data is sufficient to determine directly the centroids and fluctuation widths of the E2 properties in the principal axis frame for low-lying states. The results and model implications of recent Coulomb excitation measurements of the quadrupole shapes in odd and even A nuclei will be presented. Recent measurementsmore » of E1, E2 and E3 matrix elements for collective bands in N=88 and Z=88 nuclei show that octupole correlations play an important role. These results and the implications regarding octupole deformation and reflection asymmetry will be discussed.« less

Single-order, subwavelength resonant nanograting as a uniformly hot substrate for surface-enhanced Raman spectroscopy.

PubMed

Deng, Xuegong; Braun, Gary B; Liu, Sheng; Sciortino, Paul F; Koefer, Bob; Tombler, Thomas; Moskovits, Martin

2010-05-12

The surface-enhanced Raman spectroscopy (SERS) activity and the optical reflectance of a subwavelength gold nanograting fabricated entirely using top down technologies on silicon wafers are presented. The grating consists of 120 nm gold cladding on top of parallel silica nanowires constituting the grating's lines, with gaps between nanowires <10 nm wide at their narrowest point. The grating produces inordinately intense SERS and shows very strong polarization dependence. Reflectance measurements for the optimized grating indicate that (when p-polarization is used and at least one of the incident electric field components lies across the grating lines) the reflectance drops to <1% at resonance, indicating that essentially all of the radiant energy falling on the surface is coupled into the grating. The SERS intensity and the reflectance at resonance anticorrelate predicatively, suggesting that reflectance measurements can provide a nondestructive, wafer-level test of SERS efficacy. The SERS performance of the gratings is very uniform and reproducible. Extensive measurements on samples cut from both the same wafer and from different wafers, produce a SERS intensity distribution function that is similar to that obtained for ordinary Raman measurements carried out at multiple locations on a polished (100) silicon wafer.

Electron cyclotron resonance ion source plasma characterization by X-ray spectroscopy and X-ray imaging

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

Mascali, David, E-mail: davidmascali@lns.infn.it; Castro, Giuseppe; Celona, Luigi

2016-02-15

An experimental campaign aiming to investigate electron cyclotron resonance (ECR) plasma X-ray emission has been recently carried out at the ECRISs—Electron Cyclotron Resonance Ion Sources laboratory of Atomki based on a collaboration between the Debrecen and Catania ECR teams. In a first series, the X-ray spectroscopy was performed through silicon drift detectors and high purity germanium detectors, characterizing the volumetric plasma emission. The on-purpose developed collimation system was suitable for direct plasma density evaluation, performed “on-line” during beam extraction and charge state distribution characterization. A campaign for correlating the plasma density and temperature with the output charge states and themore » beam intensity for different pumping wave frequencies, different magnetic field profiles, and single-gas/gas-mixing configurations was carried out. The results reveal a surprisingly very good agreement between warm-electron density fluctuations, output beam currents, and the calculated electromagnetic modal density of the plasma chamber. A charge-coupled device camera coupled to a small pin-hole allowing X-ray imaging was installed and numerous X-ray photos were taken in order to study the peculiarities of the ECRIS plasma structure.« less

Application of diffusion ordered-1H-nuclear magnetic resonance spectroscopy to quantify sucrose in beverages.

PubMed

Cao, Ruge; Nonaka, Airi; Komura, Fusae; Matsui, Toshiro

2015-03-15

This work focuses on a quantitative analysis of sucrose using diffusion ordered-quantitative (1)H-nuclear magnetic resonance spectroscopy (DOSY-qNMR), where an analyte can be isolated from interference based on its characteristic diffusion coefficient (D) in gradient magnetic fields. The D value of sucrose in deuterium oxide at 30°C was 4.9 × 10(-10)m(2)/s at field gradient pulse from 5.0 × 10(-2) to 3.0 × 10(-1)T/m, separated from other carbohydrates (glucose and fructose). Good linearity (r(2)=0.9999) was obtained between sucrose (0.5-20.0 g/L) and the resonance area of target glucopyranosyl-α-C1 proton normalised to that of cellobiose C1 proton (100.0 g/L, as an internal standard) in 1D sliced DOSY spectrum. The DOSY-qNMR method was successfully applied to quantify sucrose in orange juice (36.1 ± 0.5 g/L), pineapple juice (53.5 ± 1.1g/L) and a sports drink (24.7 ± 0.6g/L), in good agreement with the results obtained by an F-kit method. Copyright © 2014 Elsevier Ltd. All rights reserved.

In vivo human brain biochemistry after aerobic exercise: preliminary report on functional magnetic resonance spectroscopy.

PubMed

Cağlar, Ertunga; Sabuncuoğlu, Hakan; Keskin, Tülay; Isikli, Sedat; Keskil, Semih; Korkusuz, Feza

2005-01-01

Our aim was to disclose whether the positive psychological changes observed after a single bout of aerobic exercise have a biochemical correlate that can be visualized by proton magnetic resonance spectroscopy (MRS) of the human brain. Right-handed male volunteers underwent psychological testing and MRS of the frontal lobe of the left hemisphere, both before and after 20 minutes of jogging at about 70% of their maximal aerobic capacity. Although there was a significant decrease on the postexercise anxiety test scores (z = -2.201, P < .05), there was no significant difference between the preexercise and postexercise scores of positive and negative affect. Considering both "amplitude" and "area under the curve" values calculated for the peaks of metabolites N-acetylaspartate (NAA), creatine, and choline, none were found to be significantly changed (P > .05) after the exercise. This is, to our knowledge, the first study to report on a functional application of MRS to mood states. Because it offers the ability to directly measure metabolic changes in the brain during neuronal activation, "functional MRS" may be a potential new tool that may be used as an adjunct to functional magnetic resonance imaging.

Single-voxel and multi-voxel spectroscopy yield comparable results in the normal juvenile canine brain when using 3 Tesla magnetic resonance imaging.

PubMed

Lee, Alison M; Beasley, Michaela J; Barrett, Emerald D; James, Judy R; Gambino, Jennifer M

2018-06-10

Conventional magnetic resonance imaging (MRI) characteristics of canine brain diseases are often nonspecific. Single- and multi-voxel spectroscopy techniques allow quantification of chemical biomarkers for tissues of interest and may help to improve diagnostic specificity. However, published information is currently lacking for the in vivo performance of these two techniques in dogs. The aim of this prospective, methods comparison study was to compare the performance of single- and multi-voxel spectroscopy in the brains of eight healthy, juvenile dogs using 3 Tesla MRI. Ipsilateral regions of single- and multi-voxel spectroscopy were performed in symmetric regions of interest of each brain in the parietal (n = 3), thalamic (n = 2), and piriform lobes (n = 3). In vivo single-voxel spectroscopy and multi-voxel spectroscopy metabolite ratios from the same size and multi-voxel spectroscopy ratios from different sized regions of interest were compared. No significant difference was seen between single-voxel spectroscopy and multi-voxel spectroscopy metabolite ratios for any lobe when regions of interest were similar in size and shape. Significant lobar single-voxel spectroscopy and multi-voxel spectroscopy differences were seen between the parietal lobe and thalamus (P = 0.047) for the choline to N-acetyl aspartase ratios when large multi-voxel spectroscopy regions of interest were compared to very small multi-voxel spectroscopy regions of interest within the same lobe; and for the N-acetyl aspartase to creatine ratios in all lobes when single-voxel spectroscopy was compared to combined (pooled) multi-voxel spectroscopy datasets. Findings from this preliminary study indicated that single- and multi-voxel spectroscopy techniques using 3T MRI yield comparable results for similar sized regions of interest in the normal canine brain. Findings also supported using the contralateral side as an internal control for dogs with brain lesions. © 2018 American College of

Phase-encoded single-voxel magnetic resonance spectroscopy for suppressing outer volume signals at 7 Tesla.

PubMed

Li, Ningzhi; An, Li; Johnson, Christopher; Shen, Jun

2017-01-01

Due to imperfect slice profiles, unwanted signals from outside the selected voxel may significantly contaminate metabolite signals acquired using in vivo magnetic resonance spectroscopy (MRS). The use of outer volume suppression may exceed the SAR threshold, especially at high field. We propose using phase-encoding gradients after radiofrequency (RF) excitation to spatially encode unwanted signals originating from outside of the selected single voxel. Phase-encoding gradients were added to a standard single voxel point-resolved spectroscopy (PRESS) sequence which selects a 2 × 2 × 2 cm 3 voxel. Subsequent spatial Fourier transform was used to encode outer volume signals. Phantom and in vivo experiments were performed using both phase-encoded PRESS and standard PRESS at 7 Tesla. Quantification was performed using fitting software developed in-house. Both phantom and in vivo studies showed that spectra from the phase-encoded PRESS sequence were relatively immune from contamination by oil signals and have more accurate quantification results than spectra from standard PRESS spectra of the same voxel. The proposed phase-encoded single-voxel PRESS method can significantly suppress outer volume signals that may appear in the spectra of standard PRESS without increasing RF power deposition.

Rapid Identification of Candida Species by Using Nuclear Magnetic Resonance Spectroscopy and a Statistical Classification Strategy

PubMed Central

Himmelreich, Uwe; Somorjai, Ray L.; Dolenko, Brion; Lee, Ok Cha; Daniel, Heide-Marie; Murray, Ronan; Mountford, Carolyn E.; Sorrell, Tania C.

2003-01-01

Nuclear magnetic resonance (NMR) spectra were acquired from suspensions of clinically important yeast species of the genus Candida to characterize the relationship between metabolite profiles and species identification. Major metabolites were identified by using two-dimensional correlation NMR spectroscopy. One-dimensional proton NMR spectra were analyzed by using a staged statistical classification strategy. Analysis of NMR spectra from 442 isolates of Candida albicans, C. glabrata, C. krusei, C. parapsilosis, and C. tropicalis resulted in rapid, accurate identification when compared with conventional and DNA-based identification. Spectral regions used for the classification of the five yeast species revealed species-specific differences in relative amounts of lipids, trehalose, polyols, and other metabolites. Isolates of C. parapsilosis and C. glabrata with unusual PCR fingerprinting patterns also generated atypical NMR spectra, suggesting the possibility of intraspecies discontinuity. We conclude that NMR spectroscopy combined with a statistical classification strategy is a rapid, nondestructive, and potentially valuable method for identification and chemotaxonomic characterization that may be broadly applicable to fungi and other microorganisms. PMID:12902244

Magnetic resonance spectroscopy of current hand amputees reveals evidence for neuronal-level changes in former sensorimotor cortex

PubMed Central

Choi, In-Young; Lee, Phil; Peng, Huiling; Kaufman, Christina L.; Frey, Scott H.

2017-01-01

Deafferentation is accompanied by large-scale functional reorganization of maps in the primary sensory and motor areas of the hemisphere contralateral to injury. Animal models of deafferentation suggest a variety of cellular-level changes including depression of neuronal metabolism and even neuronal death. Whether similar neuronal changes contribute to patterns of reorganization within the contralateral sensorimotor cortex of chronic human amputees is uncertain. We used functional MRI-guided proton magnetic resonance spectroscopy to test the hypothesis that unilateral deafferentation is associated with lower levels of N-acetylaspartate (NAA, a putative marker of neuronal integrity) in the sensorimotor hand territory located contralateral to the missing hand in chronic amputees (n = 19) compared with the analogous hand territory of age- and sex-matched healthy controls (n = 28). We also tested whether former amputees [i.e., recipients of replanted (n = 3) or transplanted (n = 2) hands] exhibit NAA levels that are indistinguishable from controls, possible evidence for reversal of the effects of deafferentation. As predicted, relative to controls, current amputees exhibited lower levels of NAA that were negatively and significantly correlated with the time after amputation. Contrary to our prediction, NAA levels in both replanted and transplanted patients fell within the range of the current amputees. We suggest that lower levels of NAA in current amputees reflects altered neuronal integrity consequent to chronic deafferentation. Thus local changes in NAA levels may provide a means of assessing neuroplastic changes in deafferented cortex. Results from former amputees suggest that these changes may not be readily reversible through reafferentation. NEW & NOTEWORTHY This study is the first to use functional magnetic resonance-guided magnetic resonance spectroscopy to examine neurochemical mechanisms underlying functional reorganization in the primary somatosensory and

Resonance ionization spectroscopy of sodium Rydberg levels using difference frequency generation of high-repetition-rate pulsed Ti:sapphire lasers

NASA Astrophysics Data System (ADS)

Naubereit, P.; Marín-Sáez, J.; Schneider, F.; Hakimi, A.; Franzmann, M.; Kron, T.; Richter, S.; Wendt, K.

2016-05-01

The generation of tunable laser light in the green to orange spectral range has generally been a deficiency of solid-state lasers. Hence, the formalisms of difference frequency generation (DFG) and optical parametric processes are well known, but the DFG of pulsed solid-state lasers was rarely efficient enough for its use in resonance ionization spectroscopy. Difference frequency generation of high-repetition-rate Ti:sapphire lasers was demonstrated for resonance ionization of sodium by efficiently exciting the well-known D1 and D2 lines in the orange spectral range (both ≈589 nm). In order to prove the applicability of the laser system for its use at resonance ionization laser ion sources of radioactive ion beam facilities, the first ionization potential of Na was remeasured by three-step resonance ionization into Rydberg levels and investigating Rydberg convergences. A result of EIP=41449.455 (6) stat(7) syscm-1 was obtained, which is in perfect agreement with the literature value of EIPlit =41449.451(2)cm-1 . A total of 41 level positions for the odd-parity Rydberg series n f 2F5/2,7/2o for principal quantum numbers of 10 ≤n ≤60 were determined experimentally.

Internal transitions of neutral (X) and negatively charged (X(-)) magneto-excitons investigated by optically detected resonance (ODR) spectroscopy

NASA Astrophysics Data System (ADS)

Nickel, Hans Andreas

Optically detected resonance (ODR) spectroscopy, an experimental technique combining spectroscopy in the far-infrared and visible regimes of the spectrum, has been applied to non-intentionally- and modulation-doped, quasi-2D GaAs/AlGaAs heterostructures at low temperatures and high magnetic fields to study internal transitions of neutral (X) and negatively charged (X--) magneto-excitons. In quasi-2D GaAs/AlGaAs heterostructures with a low density of free carriers, such as undoped multiple-quantum-wells, the ground state of optical excitations is the neutral exciton. This hydrogenic system was studied by far-infrared ODR spectroscopy, and internal excitonic transitions (IETs) 1s → np+/- from the ground state (1s) to excited states (np+/-) were found. Three samples of different well widths were studied systematically, and the behavior of the observed transitions as a function of the sample well-width was as expected. A predicted consequence of an inherent symmetry to the system was verified experimentally for the first time by the simultaneous observation of IETs and electron and hole cyclotron resonance in one sample in one experiment. In addition, it was also found, that the observability of IETs is destroyed as soon as there is a sign of X---recombination in the photoluminescence spectrum. In quantum wells with a small number of excess electrons the ground state of the system under optical excitation is the negatively charged exciton, X--. This mobile system of a hole binding two electrons differs significantly in certain aspects from its immobile impurity analogue, the negatively charged donor ion D-- . The mobility of the charged complex is tied to a hidden symmetry of magnetic translations, which leads to a new selection rule, that forbids X-- bound-to-bound transitions, in contrast to the D -- system, in which these transitions are dominant. In this dissertation, several samples that show X-- recombination in photoluminescence measurements were studied with

Electronic structure of Mo1-x Re x alloys studied through resonant photoemission spectroscopy

NASA Astrophysics Data System (ADS)

Sundar, Shyam; Banik, Soma; Sharath Chandra, L. S.; Chattopadhyay, M. K.; Ganguli, Tapas; Lodha, G. S.; Pandey, Sudhir K.; Phase, D. M.; Roy, S. B.

2016-08-01

We studied the electronic structure of Mo-rich Mo1-x Re x alloys (0≤slant x≤slant 0.4 ) using valence band photoemission spectroscopy in the photon energy range 23-70 eV and density of states calculations. Comparison of the photoemission spectra with the density of states calculations suggests that, with respect to the Fermi level E F, the d states lie mostly in the binding energy range 0 to  -6 eV, whereas s states lie in the binding energy range  -4 to  -10 eV. We observed two resonances in the photoemission spectra of each sample, one at about 35 eV photon energy and the other at about 45 eV photon energy. Our analysis suggests that the resonance at 35 eV photon energy is related to the Mo 4p-5s transition and the resonance at 45 eV photon energy is related to the contribution from both the Mo 4p-4d transition (threshold: 42 eV) and the Re 5p-5d transition (threshold: 46 eV). In the constant initial state plot, the resonance at 35 eV incident photon energy for binding energy features in the range E F (BE  =  0) to  -5 eV becomes progressively less prominent with increasing Re concentration x and vanishes for x  >  0.2. The difference plots obtained by subtracting the valence band photoemission spectrum of Mo from that of Mo1-x Re x alloys, measured at 47 eV photon energy, reveal that the Re d-like states appear near E F when Re is alloyed with Mo. These results indicate that interband s-d interaction, which is weak in Mo, increases with increasing x and influences the nature of the superconductivity in alloys with higher x.

Triple Quadrupole Versus High Resolution Quadrupole-Time-of-Flight Mass Spectrometry for Quantitative LC-MS/MS Analysis of 25-Hydroxyvitamin D in Human Serum

NASA Astrophysics Data System (ADS)

Geib, Timon; Sleno, Lekha; Hall, Rabea A.; Stokes, Caroline S.; Volmer, Dietrich A.

2016-08-01

We describe a systematic comparison of high and low resolution LC-MS/MS assays for quantification of 25-hydroxyvitamin D3 in human serum. Identical sample preparation, chromatography separations, electrospray ionization sources, precursor ion selection, and ion activation were used; the two assays differed only in the implemented final mass analyzer stage; viz. high resolution quadrupole-quadrupole-time-of-flight (QqTOF) versus low resolution triple quadrupole instruments. The results were assessed against measured concentration levels from a routine clinical chemiluminescence immunoassay. Isobaric interferences prevented the simple use of TOF-MS spectra for extraction of accurate masses and necessitated the application of collision-induced dissociation on the QqTOF platform. The two mass spectrometry assays provided very similar analytical figures of merit, reflecting the lack of relevant isobaric interferences in the MS/MS domain, and were successfully applied to determine the levels of 25-hydroxyvitamin D for patients with chronic liver disease.

A resonant ultrasound spectroscopy study of the phase transitions in Na0.75CoO2

NASA Astrophysics Data System (ADS)

Keppens, Veerle; Sergienko, Ivan; Jin, Rongying

2005-03-01

The layered transition metal oxides NaxCoO2 have attracted much interest in the past few years. Crystals with the x˜0.75 composition undergo an order-disorder transition near 340 K, a spin-density-wave transition near 22 K and other subtle transitions at intermediate temperatures. These phase transitions, likely related to a rearrangement of the Na atoms among the available sites, have been mapped out using resonant ultrasound spectroscopy. The results are modeled within the Landau theory for second order phase transitions. [Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the U.S. Dept. of Energy under contract DE-AC05-00OR22725

Proton magnetic resonance spectroscopy of late-life major depressive disorder.

PubMed

Chen, Cheng-Sheng; Chiang, I-Chan; Li, Chun-Wei; Lin, Wei-Chen; Lu, Chia-Ying; Hsieh, Tsyh-Jyi; Liu, Gin-Chung; Lin, Hsiu-Fen; Kuo, Yu-Ting

2009-06-30

The primary goal of this study was to examine the biochemical abnormalities of late-life major depression by using 3-tesla (3-T) proton magnetic resonance spectroscopy ((1)H-MRS). The antidepressant effects on the biochemical abnormalities were investigated as well. Study participants were 27 elderly patients with major depressive disorders (among which 9 were on antidepressant medication) and 19 comparison elderly subjects. (1)H-MRS spectra were acquired from voxels that were placed in the left frontal white matter, left periventricular white matter, and left basal ganglia. Ratios of N-acetylaspartate (NAA), choline (Cho) and myo-inositol to creatine were calculated. Patients with late-life major depressive disorder had a significantly lower NAA/creatine ratio in the left frontal white matter, and higher Cho/creatine and myo-inositol/creatine ratios in the left basal ganglia when compared with the control subjects. The myo-inositol correlated with global cognitive function among the patients. The biochemical abnormalities in late-life major depressive disorder were found on the left side of the frontal white matter and the basal ganglia. Neuron degeneration in the frontal white matter and second messenger system dysfunction or glial dysfunction in the basal ganglia are suggested to be associated with late-life depression.

Proton magnetic resonance spectroscopy in adult cancer patients with delirium

PubMed Central

Yager, Jeffrey R.; Magnotta, Vincent A.; Mills, James A.; Vik, Stacie M.; Weckmann, Michelle T.; Capizzano, Aristides A.; Gingrich, Roger; Beglinger, Leigh J.

2010-01-01

Background Delirium is associated with a host of negative outcomes, including increased risk of mortality, longer hospital stay, and poor long-term cognitive function. The pathophysiology of delirium is not well understood. Cancer patients undergoing a bone marrow transplant (BMT) are at high risk for developing delirium and Proton Magnetic Resonance Spectroscopy (1H-MRS) could lead to better understanding of the delirium process. Methods Fourteen BMT patients and 10 controls completed 1H-MRS, positioned above the corpus callosum, shortly after delirium onset or at study end if no delirium occurred. Results In the BMT-delirium group, statistically significantly elevated tCho/tCr was found in contrast to the BMT-no delirium group (p<0.05). The BMT–delirium group also showed statistically significantly lesser NAA/tCho compared to both controls (p=0.01) and the BMT–no delirium group (p=0.04). Conclusions Elevated choline and reduced NAA indicate inflammatory processes and white matter damage as well as neuronal metabolic impairment. Further research is needed to separate the choline peaks, as well as more detailed collection of medication regimens to determine whether a higher choline concentration is a function of the delirium process or cancer treatment effects. PMID:21227658

P-31 Magnetic Resonance Spectroscopy (MRS) of limb muscles during bedrest with exercise countermeasures

NASA Technical Reports Server (NTRS)

Berry, P.; Berry, I.; Arnaud, S.; Moseley, M.

1987-01-01

Nineteen volunteers in bed with head down tilt (-6 deg) for 1 month and doing or not exercise training while in bed (lido or ergometer) had their limb muscle studied by magnetic resonance spectroscopy. A protocol of repetitive exercise in the magnet was set and a wooden probe designed to support the limb and to allow exercise. Spectra were recorded continuously during the protocol. In each spectrum, inorganic phosphate, phosphocreatin, adenosin triphosphate, and pH were measured. All the subjects were studied before, after bedrest, and 6 weeks later. After 1 month, the lido group show no changes in the spectra of their leg muscles while the group doing no exercise or ergometer do. For the arms, a loss of muscle function is only seen in the group doing no exercise.

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

PubMed

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

2015-10-01

The aim of this study was to evaluate the transverse relaxation time of methylene resonance as compared to other lipid resonances. The examinations were performed using a 3.0 T scanner with a point-resolved spectroscopy (PRESS) sequence. Lipid relaxation time in a lipid phantom filled with canola oil was estimated with a repetition time (TR) of 6000ms and echo time (TE) of 40-550ms. For in vivo proton magnetic resonance spectroscopy ((1)H-MRS), eight male Sprague-Dawley rats were given free access to a normal-chow (NC) and another eight male Sprague-Dawley rats were given free access to a high-fat (HF) diet. Both groups drank water ad libitum. T2 measurements in the rats' livers were conducted at a fixed TR of 6000ms and TE of 40-220ms. Exponential curve fitting quality was calculated through the coefficients of determination (R(2)). Chemical analyses of the phantom and livers were not performed, but T2 decay curves were acquired. The T2 relaxation time of methylene resonance was estimated as follows: NC rats, 37.1±4.3ms; HF rats, 31.4±1.8ms (p<0.05). The extrapolated M0 values were higher in HF rats than in NC rats (p<0.005). This study of (1)H MRS led to sufficient spectral resolution and signal-to-noise ratio differences to characterize the T2 relaxation times of methylene resonance. (1)H MRS relaxation times may be useful for quantitative characterization of various liver diseases, including fatty liver disease. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Low-frequency quadrupole impedance of undulators and wigglers

DOE PAGES

Blednykh, A.; Bassi, G.; Hidaka, Y.; ...

2016-10-25

An analytical expression of the low-frequency quadrupole impedance for undulators and wigglers is derived and benchmarked against beam-based impedance measurements done at the 3 GeV NSLS-II storage ring. The adopted theoretical model, valid for an arbitrary number of electromagnetic layers with parallel geometry, allows to calculate the quadrupole impedance for arbitrary values of the magnetic permeability μ r. Here, in the comparison of the analytical results with the measurements for variable magnet gaps, two limit cases of the permeability have been studied: the case of perfect magnets (μ r → ∞), and the case in which the magnets are fullymore » saturated (μ r = 1).« less

Photoacoustic resonance spectroscopy for biological tissue characterization

NASA Astrophysics Data System (ADS)

Gao, Fei; Feng, Xiaohua; Zheng, Yuanjin; Ohl, Claus-Dieter

2014-06-01

By "listening to photons," photoacoustics allows the probing of chromosomes in depth beyond the optical diffusion limit. Here we report the photoacoustic resonance effect induced by multiburst modulated laser illumination, which is theoretically modeled as a damped mass-string oscillator and a resistor-inductor-capacitor (RLC) circuit. Through sweeping the frequency of multiburst modulated laser, the photoacoustic resonance effect is observed experimentally on phantoms and porcine tissues. Experimental results demonstrate different spectra for each phantom and tissue sample to show significant potential for spectroscopic analysis, fusing optical absorption and mechanical vibration properties. Unique RLC circuit parameters are extracted to quantitatively characterize phantom and biological tissues.

Oligonucleotide gas-phase hydrogen/deuterium exchange with D2S in the collision cell of a quadrupole-Fourier transform ion cyclotron resonance mass spectrometer.

PubMed

Mo, Jingjie; Håkansson, Kristina

2007-10-15

We have implemented gas-phase hydrogen/deuterium exchange (HDX) experiments in the external collision cell of a hybrid quadrupole-Fourier transform ion cyclotron resonance mass spectrometer. In this configuration, multiply charged oligonucleotide anions undergo significant exchange with D(2)S at reaction intervals ranging from 0.11 to 60.1 s. For DNA homohexamers, relative exchange rates were dC(6) approximately dA(6) > dG(6) > dT(6), correlating with the gas-phase acidities of nucleobases (C > A > T > G), except for guanine. Our results are consistent with a relay mechanism in which D(2)S interacts with both a backbone phosphate group and a neutral nucleobase through hydrogen bonding. We propose that the faster exchange of polyguanosine compared to polythymidine is due to the larger size of guanine and the orientation of its labile hydrogens, which may result in gas-phase conformations more favorable for forming complexes with D(2)S. Similar trends were observed for RNA homohexamers, although their HDX rates were faster than for DNA, suggesting they can also exchange via another relay process involving the 2'-hydroxyl group. HDX of DNA duplexes further supports the involvement of nucleobase hydrogens because duplexes exchanged slower than their corresponding single strands, presumably due to the intermolecular hydrogen bonds between nucleobases. This work constitutes the first investigation of the mechanisms of oligonucleotide gas-phase HDX. Our results on duplexes show promise for application of this strategy to the characterization of structured nucleic acids.

Accumulation of methylsulfonylmethane in the human brain: identification by multinuclear magnetic resonance spectroscopy.

PubMed

Lin, A; Nguy, C H; Shic, F; Ross, B D

2001-09-15

Methylsulfonylmethane (MSM) is a widely available 'alternative' medicine. In vivo magnetic resonance spectroscopy (MRS) was used to detect and quantify MSM in the brains of four patients with memory loss and in three normal volunteers all of who had ingested MSM at the recommended doses of 1-3 g daily. MSM was detected in all subjects at concentrations of 0.42-3.40 mmole/kg brain and was equally distributed between gray and white matter. MSM was undetectable in drug-naïve normal subjects (N=25), patients screened for 'toxic exposure' (N=50) or patients examined with 1H MRS for the diagnosis of probable Alzheimer Disease (N=520) between 1991 and 2001. No adverse clinical or neurochemical effects were observed. Appearance of MSM in significant concentrations in the human brain indicates ready transfer across the intact blood-brain barrier, of a compound with no known medical benefits.

Terahertz absorber based on Fano-like resonance of inverted quadrangular frustum pyramid metal grooves and sensor application

NASA Astrophysics Data System (ADS)

Yu, Yingying; Sun, Bo

2018-07-01

We investigate the multi-resonance coupling of inverted quadrangular frustum pyramid (IQFP) groove metal arrays at terahertz frequencies. The surface plasmon resonance (SPR) and groove resonance are induced, resulting in resonance coupling. The dipole of the groove resonance drives the quadrupole of the SPR and creates a sharp Fano-like resonance. The effects of geometry parameters including the width (at the bottom) and height are analyzed in detail. The results show that with the decrease in the sidewall slope of the groove, the confinement of the groove region on the electromagnetic field decreases, thereby increasing the resonance coupling. The Fano-like resonance is enhanced. The sensitivity and quality factor are discussed. The results show that the Fano-like resonance has high sensitivity and quality factor. With the increase in the sidewall slope of the groove, the sensitivity increases, and the quality factor decreases. The results show that the Fano-like resonance of IQFP groove metal arrays has a significant potential for biological monitoring and sensing.

Long-term normal-appearing brain tissue monitoring after irradiation using proton magnetic resonance spectroscopy in vivo: Statistical analysis of a large group of patients

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

Matulewicz, Lukasz; Sokol, Maria; Michnik, Anna

2006-11-01

Purpose: The aim of this study was to detect the non-neoplastic white-matter changes vs. time after irradiation using {sup 1}H nuclear magnetic resonance (NMR) spectroscopy in vivo. Methods and Materials: A total of 394 {sup 1}H MR spectra were acquired from 100 patients (age 19-74 years; mean and median age, 43 years) before and during 2 years after radiation therapy (the mean absorbed doses calculated for the averaged spectroscopy voxels are similar and close to 20 Gy). Results: Ocilations were observed in choline-containing compounds (Cho)/creatine and phosphocreatine (Cr), Cho/N-acetylaspartate (NAA), and center of gravity (CG) of the lipid band inmore » the range of 0.7-1.5 ppm changes over time reveal oscillations. The parameters have the same 8-month cycle period; however the CG changes precede the other by 2 months. Conclusions: The results indicate the oscillative nature of the brain response to irradiation, which may be caused by the blood-brain barrier disruption and repair processes. These oscillations may influence the NMR results, depending on the cycle phase in which the NMR measurements are performed in. The earliest manifestation of radiation injury detected by magnetic resonance spectroscopy is the CG shift.« less

Quadrupole Magnetic Sorting of Porcine Islets of Langerhans

PubMed Central

Shenkman, Rustin M.; Chalmers, Jeffrey J.; Hering, Bernhard J.; Kirchhof, Nicole

2009-01-01

Islet transplantation is emerging as a treatment option for selected patients with type 1 diabetes. Inconsistent isolation, purification, and recovery of large numbers of high-quality islets remain substantial impediments to progress in the field. Removing islets as soon as they are liberated from the pancreas during digestion and circumventing the need for density gradient purification is likely to result in substantially increased viable islet yields by minimizing exposure to proteolytic enzymes, reactive oxygen intermediates, and mechanical stress associated with centrifugation. This study capitalized on the hypervascularity of islets compared with acinar tissue to explore their preferential enrichment with magnetic beads to enable immediate separation in a magnetic field utilizing a quadrupole magnetic sorting. The results demonstrate that (1) preferential enrichment of porcine islets is achievable, but homogeneous bead distribution within the pancreas is difficult to achieve with current protocols; (2) greater than 70% of islets in the dissociated pancreatic tissue were recovered by quadrupole magnetic sorting, but their purity was low; and (3) infused islets purified by density gradients and subsequently passed through quadrupole magnetic sorting had similar potency as uninfused islets. These results demonstrate proof of concept and define the steps for implementation of this technology in pig and human islet isolation. PMID:19505179

Mass selectivity of dipolar resonant excitation in a linear quadrupole ion trap.

PubMed

Douglas, D J; Konenkov, N V

2014-03-15

For mass analysis, linear quadrupole ion traps operate with dipolar excitation of ions for either axial or radial ejection. There have been comparatively few computer simulations of this process. We introduce a new concept, the excitation contour, S(q), the fraction of the excited ions that reach the trap electrodes when trapped at q values near that corresponding to the excitation frequency. Ion trajectory calculations are used to calculate S(q). Ions are given Gaussian distributions of initial positions in x and y, and thermal initial velocity distributions. To model gas damping, a drag force is added to the equations of motion. The effects of the initial conditions, ejection Mathieu parameter q, scan speed, excitation voltage and collisional damping, are modeled. We find that, with no buffer gas, the mass resolution is mostly determined by the excitation time and is given by R~dβ/dq qn, where β(q) determines the oscillation frequency, and n is the number of cycles of the trapping radio frequency during the excitation or ejection time. The highest resolution at a given scan speed is reached with the lowest excitation amplitude that gives ejection. The addition of a buffer gas can increase the mass resolution. The simulation results are in broad agreement with experiments. The excitation contour, S(q), introduced here, is a useful tool for studying the ejection process. The excitation strength, excitation time and buffer gas pressure interact in a complex way but, when set properly, a mass resolution R0.5 of at least 10,000 can be obtained at a mass-to-charge ratio of 609. Copyright © 2014 John Wiley & Sons, Ltd.

Magnetic resonance spectroscopy findings in photosensitive idiopathic generalized epilepsy.

PubMed

Aydin-Ozemir, Zeynep; Terzibasioglu, Ege; Altindag, Ebru; Sencer, Serra; Baykan, Betul

2010-01-01

Studies investigating the pathophysiology of epileptic photosensitivity indicate variable involvement of particular brain regions. Our aim was to identify metabolic differences between photosensitive idiopathic generalized epilepsy (IGE) patients and nonphotosensitive IGE patients and normal healthy subjects by using Magnetic Resonance Spectroscopy (MRS). Fourteen patients diagnosed with photosensitive IGE were investigated. The control groups consisted of 14 age- and sex-matched healthy volunteers and 14 IGE patients without photosensitivity. MRS measurements of N-acetylaspartate (NAA), choline-containing compounds (Cho), creatine (Cr) were performed in the frontal and occipital cortex and the thalamus bilaterally using a stimulated echo acquisition mode (STEAM) technique with a voxel size of 20 x 20 x 20 mm. The values of the patients with IGE were compared with those of the normal controls and within subgroups according to the clinical variables by appropriate statistical tests. Photosensitive IGE patients showed significantly decreased concentrations of NAA in the right frontal lobe and left thalamus, decreased NAA/Cr ratio in left thalamus and significantly increased concentrations of Cho/Cr ratio in the right frontal lobe and NAA/Cr in the left occipital lobe when compared to normal controls. Furthermore, left occipital NAA concentration increased and left thalamus NAA/Cr ratios were decreased from the IGE patients without photosensitivity but without reaching statistical significance. Our results support previous MR studies suggesting an asymmetrical neuronal dysfunction in favor of the dominant occipital cortex and thalamus in photosensitive IGE patients.

Strong dipole and higher multi-pole Mie resonance modes with all-dielectric nanoring metasurfaces structure

NASA Astrophysics Data System (ADS)

Zhu, Huihui; Jing, Xufeng; Zhou, Pengwei

2018-01-01

Strong electric and magnetic dipole in infrared region and higher order multi-pole resonance at visible wavelengths are observed in all-dielectric nanoring metasurfaces. We discuss some of the parameters that influence the optical response of the dielectric nanoring. Adjustment of nanoring radius (inner radius and outer radius) and height can change the absorption intensity and the resonance peaks. Dipole, quadrupole, six-pole and ten-pole resonance modes can be found in the silicon nanoring at resonance wavelength. The transmission spectrum of nanoring with high Q-factor and contrast is achieved with appropriate parameters. Further the nanoring is used to application of sensing in which the sensitivity reaches 228 nm/RIU. This research is an important step to understand resonance in silicon nanoring and paves way for designing some optic devices such as sensor, nanoantennas, and photovoltaics.

IR/THz Double Resonance Spectroscopy Approach for Remote Chemical Detection at Atmospheric Pressure

NASA Astrophysics Data System (ADS)

Tanner, Elizabeth A.; Phillips, Dane J.; De Lucia, Frank C.; Everitt, Henry O.

2013-06-01

A remote sensing methodology based on infrared/terahertz (IR/THz) double resonance (DR) spectroscopy is shown to overcome limitations traditionally associated with either IR or THz spectroscopic approaches for detecting trace gases in an atmosphere. The applicability of IR/THz DR spectroscopy is explored by estimating the IR and THz power requirements for detecting a 100 part-per-million-meter cloud of methyl fluoride, methyl chloride, or methyl bromide at ranges up to 1km in three atmospheric windows below 0.3 THz. These prototypical molecules are used to ascertain the dependence of the DR signal-to-noise ratio on IR and THz beam power. A line-tunable CO_2 laser with 100 ps pulse duration generates a DR signature in four rotational transitions on a time scale commensurate with collisional relaxations caused by atmospheric N_2 and O_2. A continuous wave THz beam is frequency tuned to probe one of these rotational transitions so that laser-induced absorption variations in the analyte cloud are detected as temporal power fluctuations synchronized with the laser pulses. A combination of molecule-specific physics and scenario-dependent atmospheric conditions are used to predict the signal-to-noise ratio (SNR) for detecting an analyte as a function of cloud column density. A methodology is presented by which the optimal IR/THz pump/probe frequencies are identified. These estimates show the potential for low concentration chemical detection in a challenging atmospheric scenario with currently available or near term hardware components.

Soft X-ray absorption spectroscopy and resonant inelastic X-ray scattering spectroscopy below 100 eV: probing first-row transition-metal M-edges in chemical complexes

PubMed Central

Wang, Hongxin; Young, Anthony T.; Guo, Jinghua; Cramer, Stephen P.; Friedrich, Stephan; Braun, Artur; Gu, Weiwei

2013-01-01

X-ray absorption and scattering spectroscopies involving the 3d transition-metal K- and L-edges have a long history in studying inorganic and bioinorganic molecules. However, there have been very few studies using the M-edges, which are below 100 eV. Synchrotron-based X-ray sources can have higher energy resolution at M-edges. M-edge X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS) could therefore provide complementary information to K- and L-edge spectroscopies. In this study, M 2,3-edge XAS on several Co, Ni and Cu complexes are measured and their spectral information, such as chemical shifts and covalency effects, are analyzed and discussed. In addition, M 2,3-edge RIXS on NiO, NiF2 and two other covalent complexes have been performed and different d–d transition patterns have been observed. Although still preliminary, this work on 3d metal complexes demonstrates the potential to use M-edge XAS and RIXS on more complicated 3d metal complexes in the future. The potential for using high-sensitivity and high-resolution superconducting tunnel junction X-ray detectors below 100 eV is also illustrated and discussed. PMID:23765304

The exact calculation of quadrupole sources for some incompressible flows

NASA Technical Reports Server (NTRS)

Brentner, Kenneth S.

1988-01-01

This paper is concerned with the application of the acoustic analogy of Lighthill to the acoustic and aerodynamic problems associated with moving bodies. The Ffowcs Williams-Hawkings equation, which is an interpretation of the acoustic analogy for sound generation by moving bodies, manipulates the source terms into surface and volume sources. Quite often in practice the volume sources, or quadrupoles, are neglected for various reasons. Recently, Farassat, Long and others have attempted to use the FW-H equation with the quadrupole source and neglected to solve for the surface pressure on the body. The purpose of this paper is to examine the contribution of the quadrupole source to the acoustic pressure and body surface pressure for some problems for which the exact solution is known. The inviscid, incompressible, 2-D flow, calculated using the velocity potential, is used to calculate the individual contributions of the various surface and volume source terms in the FW-H equation. The relative importance of each of the sources is then assessed.

Assessment of diabetic neuropathy with emission tomography and magnetic resonance spectroscopy.

PubMed

Rao, Harshvardhan; Gaur, Neeraj; Tipre, Dnyanesh

2017-04-01

Diabetic neuropathies (DNs) are nerve-damaging disorders associated with diabetes. They are commonly attributed to peripheral nerves and primarily affect the limbs of the patient. They cause altered sensitivity to external stimuli along with loss in balance and reflexes of the affected patient. DNs are associated with a variety of clinical manifestations including autonomic failure and are caused by poor management of blood sugar levels. Imaging modalities provide vital information about early physiological changes in DNs. This review summarizes contributions by various teams of scientists in developing imaging methods to assess physiological changes in DNs and ongoing clinical trials where imaging modalities are applied to evaluate therapeutic intervention in DNs. Development of PET, single photon emission computed tomography, and magnetic resonance spectroscopy methods over the past 20 years are reviewed in the diagnostic assessment of DNs. Abnormal radiotracer pharmacokinetics and neurometabolite spectra in affected organs confirm physiological abnormalities in DN. With the use of the Siemens Biograph mMR and GE Signa - 60 cm (PET/MRI scanner), simultaneous acquisition of physiological and anatomical information could enhance understanding of DNs and accelerate drug development.

New perspectives in laser analytics: Resonance-enhanced multiphoton ionization in a Paul ion trap combined with a time-of-flight mass spectrometer

NASA Astrophysics Data System (ADS)

Bisling, Peter; Heger, Hans Jörg; Michaelis, Walfried; Weitkamp, Claus; Zobel, Harald

1995-04-01

A new laser analytical device has been developed that is based on resonance-enhanced multiphoton ionization in the very center of a radio-frequency quadrupole ion trap. Applications in speciation anlaysis of biological and enviromental samples and in materials science will all benefit from laser-optical selectivity in the resonance excitation process, combined with mass-spectropic sensivity which is further enhanced by the ion accumulation and storage capability.

Role of proton magnetic resonance spectroscopy in the diagnosis of gliomatosis cerebri: a unique pattern of normal choline but elevated Myo-inositol metabolite levels.

PubMed

Mohana-Borges, Aurea V R; Imbesi, Steven G; Dietrich, Rosalind; Alksne, John; Amjadi, Darius K

2004-01-01

A patient with histologically proven gliomatosis cerebri presented with a normal choline level but a markedly abnormal elevated myo-inositol level on magnetic resonance (MR) spectroscopy. We describe the case presentation, imaging findings (in particular, the unique MR spectroscopic pattern), and their significance regarding the diagnosis of this relatively rare neoplasm.

Proton Resonance Spectroscopy in CALCIUM-40.

NASA Astrophysics Data System (ADS)

Warthen, Barry Joseph

1987-09-01

The differential cross sections for the ^{39}K(p,p_{ rm o})^{39}K and ^{39}K(p,alpha_ {rm o})^{36}Ar reactions have been measured for E_{ rm p} = 1.90 to 4.02 MeV at laboratory angles theta = 90^ circ, 108^circ, 150^circ and 165^ circ. Data were taken with the Triangle Universities Nuclear Laboratory (TUNL) KN Van de Graaff accelerator and the associated high resolution system. The targets consisted of 1-2 mug/cm^2 of potassium carbonate (K_2CO _3), enriched to 99.97% ^{39}K, evaporated onto gold coated carbon backings. Excitation functions were measured in proton energy steps varying from 100 to 400 eV. The energy region studied corresponds to an excitation energy range in the ^{40}Ca nucleus of E_{rm x} = 10.2 to 12.3 MeV. A multi-level multi-channel R-matrix based computer code was used to fit the experimental excitation functions. Resonance parameters obtained include resonance energy, spin, parity, partial widths, and channel spin and orbital angular momentum mixing ratios. Of the 248 resonances observed in the proton channel, 148 were also observed in the alpha channel. A fit to the observed level density yielded a nuclear temperature of 1.5 MeV. The data were compared with predictions of statistical theories of energy levels for both level spacing and reduced width distributions. The alpha reduced widths agree with the Porter-Thomas distribution and suggest that only 5-10% of the states with alpha widths were not observed. The summed strength in each of the alpha channels represents a significant fraction of the Wigner limit for these channels. The proton channels, on the other hand, generally have much smaller fractions. The two proton s-wave strength functions are equal and thus show no evidence for spin-exchange forces in the nucleon-nucleus interaction.

Magnetic resonance spectroscopy in congenital heart disease.

PubMed Central

Miall-Allen, V. M.; Kemp, G. J.; Rajagopalan, B.; Taylor, D. J.; Radda, G. K.; Haworth, S. G.

1996-01-01

OBJECTIVE: To determine the feasibility of studying myocardial and skeletal muscle bioenergetics using 31P magnetic resonance spectroscopy (MRS) in babies and young children with congenital heart disease. SUBJECTS: 16 control subjects aged 5 months to 24 years and 18 patients with CHD, aged 7 months to 23 years, of whom 11 had cyanotic CHD, five had cardiac failure, and two had had a Senning procedure. DESIGN: 31P MRS was carried out using a 1.9 Tesla horizontal 65 cm bore whole body magnet to study the myocardium in 10 patients and skeletal muscle (gastrocnemius) in 14 patients, eight of whom were exercised, together with appropriate controls. RESULTS: In hypoxaemic patients, in skeletal muscle at rest intracellular pH (pHi) was abnormally high [7.06 (SEM 0.04) v 7.04 (0.05), P < 0.01] and showed a positive correlation with haemoglobin (P < 0.03). On exercise, hypoxaemic patients fatigued more quickly but end-exercise pHi and phosphocreatine recovery were normal, implying that an equivalent but smaller amount of work had been performed. End-exercise ADP concentration was lower. On recovery, the initial rate of phosphocreatine resynthesis was low. Skeletal muscle bioenergetics were within normal limits in those in heart failure. In the myocardium, the phosphocreatine/ATP ratio was similar in controls and hypoxaemic subjects, but low in those in heart failure. CONCLUSIONS: In heart failure, the myocardial phosphocreatine/ATP ratio was reduced, as in adults, while resting skeletal muscle studies were normal. By contrast, hypoxaemic children had normal myocardial bioenergetics, but showed skeletal muscle alkalinity, and energy reserves were more readily depleted on exercise. On recovery, the initially slow phosphocreatine resynthesis rate reflects a low rate of mitochondrial ATP synthesis, probably due to an inadequate oxygen supply. 31P MRS offers a safe, non-invasive method of studying myocardial and skeletal muscle bioenergetics in children as young as 5 months

Influence of kinetic effects on the resonance behavior of the Multipole Resonance Probe

NASA Astrophysics Data System (ADS)

Oberrath, Jens; Mussenbrock, Thomas; Brinkmann, Ralf Peter

2012-10-01

Active plasma resonance spectroscopy is a well known diagnostic method. Many concepts of this method are theoretically investigated and realized as a diagnostic tool. One of these tools is the multipole resonance probe (MRP) [1]. The application of such a probe in plasmas with pressures of only a few Pa raises the question whether kinetic effects have to be taken into account or not. To address this question a kinetic model is necessary. A general kinetic model for an electrostatic concept of active plasma resonance spectroscopy has already been presented by the authors [2]. This model can be used to describe the dynamical behavior of the MRP, which is interpretable as a special case of the general model. Neglecting electron-neutral collisions, this model can be solved analytically. Based on this solution we derive an approximated expression for the admittance of the system to investigate the influence of kinetic effects on the resonance behavior of the MRP. [4pt] [1] M. Lapke et al., Plasma Sources Sci. Technol. 20, 2011, 042001[0pt] [2] J. Oberrath et al., Proceedings of the 30th International Conference on Phenomena in Ionized Gases, 28th August - 2nd September, 2011