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

DOE R&D Accomplishments Database

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

1989-09-01

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

Production of a beam of highly vibrationally excited CO using perturbations.

PubMed

Bartels, Nils; Schäfer, Tim; Hühnert, Jens; Field, Robert W; Wodtke, Alec M

2012-06-07

An intense molecular beam of CO (X(1)Σ(+)) in high vibrational states (v = 17, 18) was produced by a new approach that we call PUMP - PUMP - PERTURB and DUMP. The basic idea is to access high vibrational states of CO e(3)Σ(-) via a two-photon doubly resonant transition that is perturbed by the A(1)Π state. DUMP -ing from this mixed (predominantly triplet) state allows access to high vibrational levels of CO (X(1)Σ(+)). The success of the approach, which avoids the use of vacuum UV radiation in any of the excitation steps, is proven by laser induced fluorescence and resonance enhanced multi-photon ionization spectroscopy.

Production of a beam of highly vibrationally excited CO using perturbations

NASA Astrophysics Data System (ADS)

Bartels, Nils; Schäfer, Tim; Hühnert, Jens; Field, Robert W.; Wodtke, Alec M.

2012-06-01

An intense molecular beam of CO (X1Σ+) in high vibrational states (v = 17, 18) was produced by a new approach that we call PUMP - PUMP - PERTURB and DUMP. The basic idea is to access high vibrational states of CO e3Σ- via a two-photon doubly resonant transition that is perturbed by the A1Π state. DUMP -ing from this mixed (predominantly triplet) state allows access to high vibrational levels of CO (X1Σ+). The success of the approach, which avoids the use of vacuum UV radiation in any of the excitation steps, is proven by laser induced fluorescence and resonance enhanced multi-photon ionization spectroscopy.

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

Fourier Deconvolution Methods for Resolution Enhancement in Continuous-Wave EPR Spectroscopy.

PubMed

Reed, George H; Poyner, Russell R

2015-01-01

An overview of resolution enhancement of conventional, field-swept, continuous-wave electron paramagnetic resonance spectra using Fourier transform-based deconvolution methods is presented. Basic steps that are involved in resolution enhancement of calculated spectra using an implementation based on complex discrete Fourier transform algorithms are illustrated. Advantages and limitations of the method are discussed. An application to an experimentally obtained spectrum is provided to illustrate the power of the method for resolving overlapped transitions. © 2015 Elsevier Inc. All rights reserved.

Nonlinear dynamics of trions under strong optical excitation in monolayer MoSe2.

PubMed

Ye, Jialiang; Yan, Tengfei; Niu, Binghui; Li, Ying; Zhang, Xinhui

2018-02-05

By employing ultrafast transient reflection measurements based on two-color pump-probe spectroscopy, the population and valley polarization dynamics of trions in monolayer MoSe 2 were investigated at relatively high excitation densities under near-resonant excitation. Both the nonlinear dynamic photobleaching of the trion resonance and the redshift of the exciton resonance were found to be responsible for the excitation-energy- and density-dependent transient reflection change as a result of many-body interactions. Furthermore, from the polarization-resolved measurements, it was revealed that the initial fast population and polarization decay process upon strong photoexcitation observed for trions was determined by trion formation, transient phase-space filling and the short valley lifetime of excitons. The results provide a basic understanding of the nonlinear dynamics of population and valley depolarization of trions, as well as exciton-trion correlation in atomically thin MoSe 2 and other transition metal dichalcogenide materials.

Basic Principles of Spectroscopy

NASA Astrophysics Data System (ADS)

Penner, Michael H.

Spectroscopy deals with the production, measurement, and interpretation of spectra arising from the interaction of electromagnetic radiation with matter. There are many different spectroscopic methods available for solving a wide range of analytical problems. The methods differ with respect to the species to be analyzed (such as molecular or atomic spectroscopy), the type of radiation-matter interaction to be monitored (such as absorption, emission, or diffraction), and the region of the electromagnetic spectrum used in the analysis. Spectroscopic methods are very informative and widely used for both quantitative and qualitative analyses. Spectroscopic methods based on the absorption or emission of radiation in the ultraviolet (UV), visible (Vis), infrared (IR), and radio (nuclear magnetic resonance, NMR) frequency ranges are most commonly encountered in traditional food analysis laboratories. Each of these methods is distinct in that it monitors different types of molecular or atomic transitions. The basis of these transitions is explained in the following sections.

Radionuclides in nephrology

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

Lausanne, A.B.D.

In 47 expert contributions, this volume provides a summary of the latest research on radionuclides in nephro-urology together with current and new clinical applications especially in renovascular hypertension, kidney transplantation, and metabolic and urological diseases. In addition, attention is given to aspects of basic renal physiology and function and possible applications of nuclear magnetic resonance and spectroscopy in nephro-urology. New testing procedures which promise to improve diagnosis, and new radiopharmaceuticals are described. The reports are divided into eight sections, the first of which features studies on the renin-angiotensin system, cisplatin, atrial natriuretic factor and determining plasma oxalate. Four papers describemore » a number of new radiopharmaceuticals which have the potential to replace hippuran. In the third section, radionuclide methods for the measurement of renal function parameters are discussed. The book then focuses on the potential role of captopril in the improved diagnosis of renovascular hypertension. Applications of nuclear magnetic resonance and spectroscopy are demonstrated in the diagnosis of acute pyelonephritis, kidney assessment after lithotripsy, kidney evaluation prior to transplantation, and in monitoring renal ischemia during hypotension.« less

Technical and experimental features of Magnetic Resonance Spectroscopy of brain glycogen metabolism.

PubMed

Soares, Ana Francisca; Gruetter, Rolf; Lei, Hongxia

2017-07-15

In the brain, glycogen is a source of glucose not only in emergency situations but also during normal brain activity. Altered brain glycogen metabolism is associated with energetic dysregulation in pathological conditions, such as diabetes or epilepsy. Both in humans and animals, brain glycogen levels have been assessed non-invasively by Carbon-13 Magnetic Resonance Spectroscopy ( 13 C-MRS) in vivo. With this approach, glycogen synthesis and degradation may be followed in real time, thereby providing valuable insights into brain glycogen dynamics. However, compared to the liver and muscle, where glycogen is abundant, the sensitivity for detection of brain glycogen by 13 C-MRS is inherently low. In this review we focus on strategies used to optimize the sensitivity for 13 C-MRS detection of glycogen. Namely, we explore several technical perspectives, such as magnetic field strength, field homogeneity, coil design, decoupling, and localization methods. Furthermore, we also address basic principles underlying the use of 13 C-labeled precursors to enhance the detectable glycogen signal, emphasizing specific experimental aspects relevant for obtaining kinetic information on brain glycogen. Copyright © 2016 Elsevier Inc. All rights reserved.

A Study of Ziegler–Natta Propylene Polymerization Catalysts by Spectroscopic Methods

PubMed Central

Tkachenko, Olga P.; Kucherov, Alexey V.; Kustov, Leonid M.; Virkkunen, Ville; Leinonen, Timo; Denifl, Peter

2017-01-01

Ziegler–Natta polymerization catalysts were characterized by a complex of surface- and bulk-sensitive methods (DRIFTS, XPS, ESR, and XAS = XANES + EXAFS). A diffuse-reflectance Fourier-transform IR spectroscopy (DRIFTS) study showed the presence of strong Lewis acid sites in different concentrations and absence of strong basic sites in the polymerization catalysts. X-ray photoelectron spectroscopy (XPS), electron-spin resonance (ESR), and (X-ray absorption near-edge structure (XANES) analysis revealed the presence of Ti4+, Ti3+, Ti2+, and Ti1+ species in the surface layers and in the bulk of catalysts. The samples under study differ drastically in terms of the number of ESR-visible paramagnetic sites. The EXAFS study shows the presence of a Cl atom as a nearest neighbor of the absorbing Ti atom. PMID:28772850

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

Fluorescence properties of Yb3+-Er3+ co-doped phosphate glasses containing silver nanoparticles

NASA Astrophysics Data System (ADS)

Martínez Gámez, Ma A.; Vallejo H, Miguel A.; Kiryanov, A. V.; Licea-Jiménez, L.; Lucio M, J. L.; Pérez-García, S. A.

2018-04-01

Er3+-Yb3+ co-doped phosphate glasses containing silver nitrate (SN), were fabricated. Transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy (XPS) analyses were used to evidence the nucleation and presence of silver nanoparticles (SNP). The basic parameters of the glasses were inspected by means of absorption and fluorescence spectra, and fluorescence lifetimes under excitation at 916 nm (in-band of Yb3+), and at 406 nm (in-band of surface plasmon resonance given by the presence of SNP). The spectra as well as estimates for the basic parameters defining the lasing/amplifying potential of the glasses were studied as a function of SN concentration. The experimental results indicate that by increasing the SN content an enhancement of Er3+/Yb3+ fluorescence takes place.

Low pressure characteristics of the multipole resonance probe

NASA Astrophysics Data System (ADS)

Brinkmann, Ralf Peter; Oberrath, Jens

2014-10-01

The term ``Active plasma resonance spectroscopy'' (APRS) denotes a class of related techniques which utilize, for diagnostic purposes, the natural ability of plasmas to resonate on or near the electron plasma frequency ωpe. The basic idea dates back to the early days of discharge physics but has recently found renewed interest as an approach to industry-compatible plasma diagnostics: A radio frequent signal (in the GHz range) is coupled into the plasma via an antenna or probe, the spectral response is recorded (with the same or another antenna or probe), and a mathematical model is used to determine plasma parameters like the electron density or the electron temperature. When the method is applied to low pressure plasmas (of a few Pa and lower), kinetic effects must be accounted for in the mathematical model. This contribution studies a particular realization of the APRS scheme, the geometrically and electrically symmetric Multipole Resonance Probe (MRP). It is shown that the resonances of the MRP exhibit a residual damping in the limit p --> 0 which cannot be explained by Ohmic dissipation but only by kinetic effects. Supported by the German Federal Ministry of Education and Research (BMBF) in the framework of the PluTO project.

Quantitative MRI and spectroscopy of bone marrow

PubMed Central

Ruschke, Stefan; Dieckmeyer, Michael; Diefenbach, Maximilian; Franz, Daniela; Gersing, Alexandra S.; Krug, Roland; Baum, Thomas

2017-01-01

Bone marrow is one of the largest organs in the human body, enclosing adipocytes, hematopoietic stem cells, which are responsible for blood cell production, and mesenchymal stem cells, which are responsible for the production of adipocytes and bone cells. Magnetic resonance imaging (MRI) is the ideal imaging modality to monitor bone marrow changes in healthy and pathological states, thanks to its inherent rich soft‐tissue contrast. Quantitative bone marrow MRI and magnetic resonance spectroscopy (MRS) techniques have been also developed in order to quantify changes in bone marrow water–fat composition, cellularity and perfusion in different pathologies, and to assist in understanding the role of bone marrow in the pathophysiology of systemic diseases (e.g. osteoporosis). The present review summarizes a large selection of studies published until March 2017 in proton‐based quantitative MRI and MRS of bone marrow. Some basic knowledge about bone marrow anatomy and physiology is first reviewed. The most important technical aspects of quantitative MR methods measuring bone marrow water–fat composition, fatty acid composition, perfusion, and diffusion are then described. Finally, previous MR studies are reviewed on the application of quantitative MR techniques in both healthy aging and diseased bone marrow affected by osteoporosis, fractures, metabolic diseases, multiple myeloma, and bone metastases. Level of Evidence: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:332–353. PMID:28570033

Resonant Polarization Spectroscopy for Hot X-ray Plasmas

DOE PAGES

Chen, Guo -Xin

2016-04-28

X-ray line polarization spectroscopy is a method of choice for probing hot plasma conditions. The precise roles of resonant structures in this method have not been realized and fully understood. With a sophisticated relativistic close coupling Dirac R-matrix calculation of polarized radiation of the quadrupole magnetic M2 line at 2.717 Å in Ba 46+, we revealed the nature of resonant structures in x-ray line polarization spectroscopy. We found that signatures with a heavy resonance forest imprinting on polarization may be used for a sensitive new spectroscopic method. The resonant polarization spectrum was used to determine or constrain the directional beammore » electron distribution of the laboratory Ba plasma. Lastly, our results provide a start of resonant polarization spectroscopy as a method for diagnostics of laboratory, fusion and astrophysical plasma source conditions.« less

NMR Spectroscopy in Glass Science: A Review of the Elements

PubMed Central

2018-01-01

The study of inorganic glass structure is critically important for basic glass science and especially the commercial development of glasses for a variety of technological uses. One of the best means by which to achieve this understanding is through application of solid-state nuclear magnetic resonance (NMR) spectroscopy, which has a long and interesting history. This technique is element specific, but highly complex, and thus, one of the many inquiries made by non-NMR specialists working in glass science is what type of information and which elements can be studied by this method. This review presents a summary of the different elements that are amenable to the study of glasses by NMR spectroscopy and provides examples of the type of atomic level structural information that can be achieved. It serves to inform the non-specialist working in glass science and technology about some of the benefits and challenges involved in the study of inorganic glass structure using modern, readily-available NMR methods. PMID:29565328

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)

Spectroscopic and optical properties of the VO2+ ion doped TeO2-TiO2-ZnO-Nb2O5 glass system

NASA Astrophysics Data System (ADS)

Swapna; Upender, G.; Sreenivasulu, V.; Prasad, M.

2016-04-01

Studies such as optical absorption, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Electron paramagnetic resonance (EPR) spectroscopy and Differential scanning calorimetry (DSC) were carried out on VO2+ ion doped TeO2-TiO2-ZnO-Nb2O5 glass system. Raman and FTIR spectra of the glasses revealed the presence of [TeO3], [TeO4] and [NbO6] structural units in the glass network. The Urbach energy (Δ E), cut-off wavelength (λ c ), optical band gap ( E opt ), optical basicity (Λ) and electron polarizability ( α) of the glasses were determined from optical absorption studies. The density ( ρ), molar volume ( V m ), oxygen molar volume ( V o ) and refractive index ( n) were also measured. Spin-Hamiltonian parameters were calculated from the EPR studies. When Nb2O5 was increased at the expense of ZnO, the density, optical band gap and Urbach energy of the glasses increased, and the electronic polarizability and optical basicity decreased. The EPR spectra clearly showed that vanadium was in the glass as VO2+ and occupied octahedral sites with tetrahedral compression. Spin-Hamiltonian parameters g‖ and g⊥ decreased as Nb2O5 content increased in the glass. The glass transition temperature ( T g ) also increased with increasing Nb2O5 content in the glass.

BBD Optimization of K-ZnO Catalyst Modification Process for Heterogeneous Transesterification of Rice Bran Oil to Biodiesel

NASA Astrophysics Data System (ADS)

Kabo, K. S.; Yacob, A. R.; Bakar, W. A. W. A.; Buang, N. A.; Bello, A. M.; Ruskam, A.

2016-07-01

Environmentally benign zinc oxide (ZnO) was modified with 0-15% (wt.) potassium through wet impregnation and used in transesterification of rice bran oil (RBO) to form biodiesel. The catalyst was characterized by X-Ray powder Diffraction (XRD), its basic sites determined by back titration and Response Surface Methodology (RSM) Box-Behnken Design (BBD) was used to optimize the modification process variables on the basic sites of the catalyst. The transesterification product, biodiesel was analyzed by Nuclear Magnetic Resonance (NMR) spectroscopy. The result reveals K-modified ZnO with highly increased basic sites. Quadratic model with high regression R2 = 0.9995 was obtained from the ANOVA of modification process, optimization at maximum basic sites criterion gave optimum modification conditions of K-loading = 8.5% (wt.), calcination temperature = 480 oC and time = 4 hours with response and basic sites = 8.14 mmol/g which is in close agreement with the experimental value of 7.64 mmol/g. The catalyst was used and a value of 95.53% biodiesel conversion was obtained and effect of potassium leaching was not significant in the process

Methods for the analysis of HIV-1 nucleocapsid protein interactions with oligonucleotides.

PubMed

Stephen, Andrew G; Fisher, Robert J

2009-01-01

HIV-1 Nucleocapsid protein (NC) is a small basic protein that contains two retroviral zinc fingers. It is a highly effective nucleic acid chaperone that plays a critical role in viral replication acting as a cofactor in reverse transcription as well as other aspects of the viral lifecycle. We have used a variety of biophysical techniques to characterize the high affinity binding of NC to a short deoxyoligonucleotide (d(TG)(4)). Here we outline in detail the use of fluorescence anisotropy and surface plasmon resonance spectroscopy to study the binding of NC to d(TG)(4).

Electrical detection of nuclear spins in organic light-emitting diodes

NASA Astrophysics Data System (ADS)

Malissa, H.; Kavand, M.; Waters, D. P.; Lupton, J. M.; Vardeny, Z. V.; Saam, B.; Boehme, C.

2014-03-01

We present pulsed combined electrically detected electron paramagnetic and nuclear magnetic resonance experiments on MEH-PPV OLEDs. Spin dynamics in these structures are governed by hyperfine interactions between charge carriers and the surrounding hydrogen nuclei, which are abundant in these materials. Hyperfine coupling has been observed by monitoring the device current during coherent spin excitation. Electron spin echoes (ESEs) are detected by applying one additional readout pulse at the time of echo formation. This allows for the application of high-resolution spectroscopy based on ESE detection, such as electron spin echo envelope modulation (ESEEM) and electron nuclear double resonance (ENDOR) available for electrical detection schemes. We conduct electrically detected ESEEM and ENDOR experiments and show how hyperfine interactions in MEH-PPV with and without deuterated polymer side groups can be observed by device current measurements. We acknowledge support by the Department of Energy, Office of Basic Energy Sciences under Award #DE-SC0000909.

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).

Label-Free Molecular Imaging of Biological Cells and Tissues by Linear and Nonlinear Raman Spectroscopic Approaches.

PubMed

Krafft, Christoph; Schmitt, Michael; Schie, Iwan W; Cialla-May, Dana; Matthäus, Christian; Bocklitz, Thomas; Popp, Jürgen

2017-04-10

Raman spectroscopy is an emerging technique in bioanalysis and imaging of biomaterials owing to its unique capability of generating spectroscopic fingerprints. Imaging cells and tissues by Raman microspectroscopy represents a nondestructive and label-free approach. All components of cells or tissues contribute to the Raman signals, giving rise to complex spectral signatures. Resonance Raman scattering and surface-enhanced Raman scattering can be used to enhance the signals and reduce the spectral complexity. Raman-active labels can be introduced to increase specificity and multimodality. In addition, nonlinear coherent Raman scattering methods offer higher sensitivities, which enable the rapid imaging of larger sampling areas. Finally, fiber-based imaging techniques pave the way towards in vivo applications of Raman spectroscopy. This Review summarizes the basic principles behind medical Raman imaging and its progress since 2012. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structural characterization and stability of dimethylaminoethanol and dimethylaminoethanol bitartrate for possible use in cosmetic firming.

PubMed

Clares, B; Ruíz, M A; Morales, M E; Tamayo, J A; Lara, V Gallardo

2010-01-01

2-Dimethylaminoethanol (DMAE) (also known as deanol) has been used as an ingredient in skin care, and in cognitive function- and mood-enhancing products. It is marketed as a free base or salt, and in theory, the two forms should be equally effective and able to substitute for each other in pharmaceutical formulations. Detecting possible alterations in the active principle is a basic part of preformulation studies. Accordingly, this study compared DMAE and DMAE bitartrate to identify potential alterations or differences between the free base and the salt that might compromise the long-term stability of cosmetic preparations at different temperatures, and also compared the behavior of the base substance and derivative alone and in solution. Samples were analyzed with different physicochemical methods such as differential scanning calorimetry, ultraviolet and infrared spectroscopy, and nuclear magnetic resonance spectroscopy.

Resonance tunneling electron-vibrational spectroscopy of polyoxometalates.

PubMed

Dalidchik, F I; Kovalevskii, S A; Balashov, E M

2017-05-21

The tunneling spectra of the ordered monolayer films of decamolybdodicobaltate (DMDC) compounds deposited from aqueous solutions on HOPG were measured by scanning tunnel microscopy in air. The DMDC spectra, as well as the tunneling spectra of other polyoxometalates (POMs), exhibit well-defined negative differential resistances (NDRs). The mechanism of formation of these spectral features was established from the collection of revealed NDR dependences on the external varying parameters and found to be common to all systems exhibiting Wannier-Stark localization. A model of biresonance tunneling was developed to provide an explanation for the totality of experimental data, both the literature and original, on the tunneling POM probing. A variant of the tunneling electron-vibrational POM spectroscopy was proposed allowing the determination of the three basic energy parameters-energy gaps between the occupied and unoccupied states, frequencies of the vibrational transitions accompanying biresonance electron-tunneling processes, and electron-vibrational interaction constants on the monomolecular level.

Resonance tunneling electron-vibrational spectroscopy of polyoxometalates

PubMed Central

Dalidchik, F. I.; Kovalevskii, S. A.

2017-01-01

The tunneling spectra of the ordered monolayer films of decamolybdodicobaltate (DMDC) compounds deposited from aqueous solutions on HOPG were measured by scanning tunnel microscopy in air. The DMDC spectra, as well as the tunneling spectra of other polyoxometalates (POMs), exhibit well-defined negative differential resistances (NDRs). The mechanism of formation of these spectral features was established from the collection of revealed NDR dependences on the external varying parameters and found to be common to all systems exhibiting Wannier–Stark localization. A model of biresonance tunneling was developed to provide an explanation for the totality of experimental data, both the literature and original, on the tunneling POM probing. A variant of the tunneling electron-vibrational POM spectroscopy was proposed allowing the determination of the three basic energy parameters—energy gaps between the occupied and unoccupied states, frequencies of the vibrational transitions accompanying biresonance electron-tunneling processes, and electron-vibrational interaction constants on the monomolecular level. PMID:28527451

Computational time-resolved and resonant x-ray scattering of strongly correlated materials

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

Bansil, Arun

Basic-Energy Sciences of the Department of Energy (BES/DOE) has made large investments in x-ray sources in the U.S. (NSLS-II, LCLS, NGLS, ALS, APS) as powerful enabling tools for opening up unprecedented new opportunities for exploring properties of matter at various length and time scales. The coming online of the pulsed photon source, literally allows us to see and follow the dynamics of processes in materials at their natural timescales. There is an urgent need therefore to develop theoretical methodologies and computational models for understanding how x-rays interact with matter and the related spectroscopies of materials. The present project addressed aspectsmore » of this grand challenge of x-ray science. In particular, our Collaborative Research Team (CRT) focused on developing viable computational schemes for modeling x-ray scattering and photoemission spectra of strongly correlated materials in the time-domain. The vast arsenal of formal/numerical techniques and approaches encompassed by the members of our CRT were brought to bear through appropriate generalizations and extensions to model the pumped state and the dynamics of this non-equilibrium state, and how it can be probed via x-ray absorption (XAS), emission (XES), resonant and non-resonant x-ray scattering, and photoemission processes. We explored the conceptual connections between the time-domain problems and other second-order spectroscopies, such as resonant inelastic x-ray scattering (RIXS) because RIXS may be effectively thought of as a pump-probe experiment in which the incoming photon acts as the pump, and the fluorescent decay is the probe. Alternatively, when the core-valence interactions are strong, one can view K-edge RIXS for example, as the dynamic response of the material to the transient presence of a strong core-hole potential. Unlike an actual pump-probe experiment, here there is no mechanism for adjusting the time-delay between the pump and the probe. However, the core hole predominantly decays via Auger processes, thereby providing an internal time-scale, which limits intermediate-state processes to timescales of a few femtoseconds. Accordingly, a number of activities directed at modeling K-, L- and M-edge RIXS in correlated materials were also pursused by our CRT. Our research effort supported by this CMCSN grant substantially advanced the understanding of x-ray scattering processes in the time-domain as well as in the more conventional scattering channels, including time-resolved photoemission, and how such processes can be modeled realistically in complex correlated materials more generally. The modeling of relaxation processes involved in time-domain spectroscopies is important also for understanding photoinduced effects such as energy conversion in photosynthesis and solar cell applications, and thus impacts the basic science for energy needs.« less

pH-sensitive nanocargo based on smart polymer functionalized graphene oxide for site-specific drug delivery.

PubMed

Kavitha, Thangavelu; Abdi, Syed Izhar Haider; Park, Soo-Young

2013-04-14

Graphene oxide (GO) was functionalized covalently with pH-sensitive poly(2-(diethylamino) ethyl methacrylate) (PDEA) by surface-initiated in situ atom transfer radical polymerization. The structure of the PDEA-grafted GO (GO-PDEA) were examined by Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis and atomic force microscopy. The grafted PDEA endowed the GO sheets with good solubility and stability in physiological solutions. Simple physisorption by π-π stacking and hydrophobic interactions on GO-PDEA can be used to load camptothecin (CPT), a widely used water-insoluble cancer drug. The loaded CPT was released only at the lower (acidic) pH normally found in a tumor environment but not in basic and neutral pH. GO-PDEA did not show practical toxicity to N2a cancer cells but the GO-PDEA-CPT complex exhibited high potency in killing N2a cancer cells in vitro. These results suggest that the GO-PDEA nanocargo carrier might be a promising material for site-specific anticancer drug delivery and controlled release.

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.

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.

A tunable single-monochromator Raman system based on the supercontinuum laser and tunable filters for resonant Raman profile measurements.

PubMed

Liu, X-L; Liu, H-N; Tan, P-H

2017-08-01

Resonant Raman spectroscopy requires that the wavelength of the laser used is close to that of an electronic transition. A tunable laser source and a triple spectrometer are usually necessary for resonant Raman profile measurements. However, such a system is complex with low signal throughput, which limits its wide application by scientific community. Here, a tunable micro-Raman spectroscopy system based on the supercontinuum laser, transmission grating, tunable filters, and single-stage spectrometer is introduced to measure the resonant Raman profile. The supercontinuum laser in combination with transmission grating makes a tunable excitation source with a bandwidth of sub-nanometer. Such a system exhibits continuous excitation tunability and high signal throughput. Its good performance and flexible tunability are verified by resonant Raman profile measurement of twisted bilayer graphene, which demonstrates its potential application prospect for resonant Raman spectroscopy.

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.

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

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.

Resonance Raman investigation of the photoreduction of methylviologen with Ru(bpy) 2+3 and proflavine as sensitizers

NASA Astrophysics Data System (ADS)

Forster, Martin; Hester, Ronald E.

1982-01-01

Reduced methylviologen (MV +) is detected by conventional resonance Raman spectroscopy in photoreactions of Ru(bpy) 2+3 or proflavine (PFH +) with MV 2+ Using apparatus for modulated excitation resonance Raman (MERR) spectroscopy, the irreversible MV + production with PFH + as sensitizer is traced back to triplet-triplet annihilation with simultaneous destruction of PFH +.

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…

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

Electronic structure of the organic semiconductor Alq3 (aluminum tris-8-hydroxyquinoline) from soft x-ray spectroscopies and density functional theory calculations.

PubMed

DeMasi, A; Piper, L F J; Zhang, Y; Reid, I; Wang, S; Smith, K E; Downes, J E; Peltekis, N; McGuinness, C; Matsuura, A

2008-12-14

The element-specific electronic structure of the organic semiconductor aluminum tris-8-hydroxyquinoline (Alq(3)) has been studied using a combination of resonant x-ray emission spectroscopy, x-ray photoelectron spectroscopy, x-ray absorption spectroscopy, and density functional theory (DFT) calculations. Resonant and nonresonant x-ray emission spectroscopy were used to measure directly the carbon, nitrogen and oxygen 2p partial densities of states in Alq(3), and good agreement was found with the results of DFT calculations. Furthermore, resonant x-ray emission at the carbon K-edge is shown to be able to measure the partial density of states associated with individual C sites. Finally, comparison of previous x-ray emission studies and the present data reveal the presence of clear photon-induced damage in the former.

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.

Two-Dimensional Resonance Raman Signatures of Vibronic Coherence Transfer in Chemical Reactions.

PubMed

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

2017-11-02

Two-dimensional resonance Raman (2DRR) spectroscopy has been developed for studies of photochemical reaction mechanisms and structural heterogeneity in condensed phase systems. 2DRR spectroscopy is motivated by knowledge of non-equilibrium effects that cannot be detected with traditional resonance Raman spectroscopy. For example, 2DRR spectra may reveal correlated distributions of reactant and product geometries 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 chapter, these capabilities of 2DRR spectroscopy are discussed in the context of recent applications to the photodissociation reactions of triiodide. We show that signatures of "vibronic coherence transfer" in the photodissociation process can be targeted with particular 2DRR pulse sequences. Key differences between the signal generation mechanisms for 2DRR and off-resonant 2D Raman spectroscopy techniques are also addressed. Overall, recent experimental developments and applications of the 2DRR method suggest that it will be a valuable tool for elucidating ultrafast chemical reaction mechanisms.

Dielectric micro-resonator-based opto-mechanical systems for sensing applications

NASA Astrophysics Data System (ADS)

Ali, Amir Roushdy

In recent years, whispering gallery mode (WGM), or morphology dependent optical resonances (MDR) of dielectric micro-resonators have attracted interest with proposed applications in a wide range of areas due to the high optical quality factors, Q, they can exhibit (reaching ~ 10. 9 for silica spheres). Micro-resonator WGMs have been used in applications that include those in spectroscopy, micro-cavity laser technology, optical communications (switching, filtering and multiplexing), sensors technologies and even chemical and biological sensing. The WGM of these dielectric micro-resonators are highly sensitive to morphological changes (such as the size, shape, or refractive index) of the resonance cavity and hence, can be tuned by causing a minute change in the physical condition of the surrounding. In this dissertation, we have been creating opto-mechanical systems, which at their most basic, are extraordinarily sensitive sensors. One of the ultimate goals of this dissertation is to develop sensors capable of detecting the extremely small electric field changes. To improve the performance of the sensors, we couple a polymer cantilever beam to a dielectric micro-resonator. The eventual use of such ultra sensitive electric filed sensors could include neural-machine interfaces for advanced prosthetics devices. The work presented here includes a basic analysis and experimental investigations of the electric field sensitivity and range of micro-resonators of several different materials and geometries followed by the electric field sensor design, testing, and characterization. Also, the effects of angular velocity on the WGM shifts of spherical micro-resonators are also investigated. The elastic deformation that is induced on a spinning resonator due to the centrifugal force may lead to a sufficient shift in the optical resonances and therefore interfering with its desirable operational sensor design. Furthermore, this principle could be used for the development of angular speed detection photonic sensors. In previous applications, the WGM shifts induced by the external effects were monitored by identifying and tracking individual resonance dip in the optical transmission spectrum. The success of the WGM sensors is strongly dependent on the precise and speeds tracking of the shifts of the resonant wavelengths. In this dissertation, we demonstrate the application of WGM micro-resonators for high-speed transient sensing (wide-bandwidth). To facilitate the use of the sensors for high-speed transient applications, we tune the interrogation laser using a harmonic rather than a ramp waveform and calibrate the laser response at various input frequencies and amplitudes using a Fabry-Perot interferometer. WGM shifts are tracked using a fast cross-correlation algorithm on the transmission spectra. We demonstrate dynamic force measurements up to 10 kHz using this approach. We also present a simple lumped-heat capacity thermal model to predict the laser's tuning response.

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.

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).

An Overview of Microbiology Research in Japan, with Notes on Medical History, Education and Health Care.

DTIC Science & Technology

1981-07-01

Kyogoku: infrared spectroscopy , Raman spectroscop , and nuclear magnetic resonance spectroscopy of protein and protein models; resonance Raman spectra...Research projects - tritium labeling techniques; heavy metal accumulations in deciduous teeth; chemistry of the mycotoxin fusarenon; EM of phage P22 DNA...fluorescence correlation spectroscopy . - Biological Activities of Biopolymers - Dr. M. Kageyama, Director: Analysis of Pseudomonas aeruginosa bacteriocins

Electronic Structure of the Organic Semiconductor Alq3 (aluminum tris-8-hydroxyquinoline) from Soft X-ray Spectroscopies and Density Functional Theory Calculations

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

DeMasi, A.; Piper, L; Zhang, Y

2008-01-01

The element-specific electronic structure of the organic semiconductor aluminum tris-8-hydroxyquinoline (Alq3) has been studied using a combination of resonant x-ray emission spectroscopy, x-ray photoelectron spectroscopy, x-ray absorption spectroscopy, and density functional theory (DFT) calculations. Resonant and nonresonant x-ray emission spectroscopy were used to measure directly the carbon, nitrogen and oxygen 2p partial densities of states in Alq3, and good agreement was found with the results of DFT calculations. Furthermore, resonant x-ray emission at the carbon K-edge is shown to be able to measure the partial density of states associated with individual C sites. Finally, comparison of previous x-ray emission studiesmore » and the present data reveal the presence of clear photon-induced damage in the former.« less

CHARACTERIZATION OF METABOLITES IN SMALL FISH BIOFLUIDS AND TISSUES BY NMR SPECTROSCOPY

EPA Science Inventory

Nuclear magnetic resonance (NMR) spectroscopy has been utilized for assessing ecotoxicity in small fish models by means of metabolomics. Two fundamental challenges of NMR-based metabolomics are the detection limit and characterization of metabolites (or NMR resonance assignments...

A Surface Plasmon Resonance-Based Method for Detection and Determination of Cannabinoids Using Silver Nanoparticles

NASA Astrophysics Data System (ADS)

Amjadi, M.; Sodouri, T.

2014-05-01

In this work, a simple colorimetric method based on the formation of silver nanoparticles (Ag NPs) was developed for the determination of cannabinoids including Δ9-tetrahydrocannabinol (Δ9-THC), cannabidiol (CBD) and cannabinol (CBN). These compounds in a basic solution at 80°C reduce [Ag(NH3)2]+ to form Ag NPs. The produced NPs were characterized by transmission electron microscopy and UV-Vis absorption spectroscopy. The brown-yellow color of the solution that results from the localized surface plasmon resonance of Ag NPs can be observed by the bare eye. The calibration graph obtained by plotting the absorbance at 410 nm versus the concentration of each analyte was linear in the range of 0.1-5.0 μg/ml for all tested cannabinoids. The limits of detection were 0.065, 0.077, and 0.052 μg/ml for Δ9-THC, CBN and CBD, respectively. The developed method was applied to the determination of total cannabinoids in hashish.

Peptide-membrane Interactions by Spin-labeling EPR

PubMed Central

Smirnova, Tatyana I.; Smirnov, Alex I.

2016-01-01

Site-directed spin labeling (SDSL) in combination with Electron Paramagnetic Resonance (EPR) spectroscopy is a well-established method that has recently grown in popularity as an experimental technique, with multiple applications in protein and peptide science. The growth is driven by development of labeling strategies, as well as by considerable technical advances in the field, that are paralleled by an increased availability of EPR instrumentation. While the method requires an introduction of a paramagnetic probe at a well-defined position in a peptide sequence, it has been shown to be minimally destructive to the peptide structure and energetics of the peptide-membrane interactions. In this chapter, we describe basic approaches for using SDSL EPR spectroscopy to study interactions between small peptides and biological membranes or membrane mimetic systems. We focus on experimental approaches to quantify peptide-membrane binding, topology of bound peptides, and characterize peptide aggregation. Sample preparation protocols including spin-labeling methods and preparation of membrane mimetic systems are also described. PMID:26477253

From quantum transitions to electronic motions

NASA Astrophysics Data System (ADS)

Krausz, Ferenc

2017-01-01

Laser spectroscopy and chromoscopy permit precision measurement of quantum transitions and captures atomic-scale dynamics, respectively. Frequency- and time-domain metrology ranks among the supreme laser disciplines in fundamental science. For decades, these fields evolved independently, without interaction and synergy between them. This has changed profoundly with controlling the position of the equidistant frequency spikes of a mode-locked laser oscillator. By the self-referencing technique invented by Theodor Hänsch, the comb can be coherently linked to microwaves and used for precision measurements of energy differences between quantum states. The resultant optical frequency synthesis has revolutionized precision spectroscopy. Locking the comb lines to the resonator round-trip frequency by the same approach has given rise to laser pulses with controlled field oscillations. This article reviews, from a personal perspective, how the bridge between frequency- and time-resolved metrology emerged on the turn of the millennium and how synthesized several-cycle laser fields have been instrumental in establishing the basic tools and techniques for attosecond science.

A new approach to the analysis of radiopharmaceuticals. Final technical report, January 15, 1987--June 30, 1991

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

Jones, A.G.; Davison, A.; Costello, C.E.

The objective of this research was to investigate analytical techniques that could be used in the study of both the basic chemistry and the radiopharmaceutical chemistry of {sup 99m}Tc. First funded in 1981, the work focused initially upon the use of high performance liquid chromatography (HPLC) and various forms of mass spectrometry for the identification of technetium species. This funding allowed the authors to combine HPLC and mass spectrometry to identify radiopharmaceuticals which, although in clinical use, had not previously been characterized. Other techniques that have been examined include resonance Raman spectroscopy and, more significantly, {sup 99}Tc nuclear magnetic resonancemore » spectroscopy (NMR), with the latter not only being used in purely chemical experiments but also in biologic studies. In 1985 a grant to the Department of Chemistry at MIT from DOE allowed the purchase of an X-ray diffractometer and access to this instrument has enabled them to broaden the analytical base with routine structural determinations.« less

Jamming Behavior of Domain Walls in an Antiferromagnetic Film

NASA Astrophysics Data System (ADS)

Sinha, Sunil

2014-03-01

Over the last few years, attempts have been made to unify many aspects of the freezing behavior of glasses, granular materials, gels, supercooled liquids, etc. into a general conceptual framework of what is called jamming behavior. This occurs when particles reach packing densities high enough that their motions become highly restricted. A general phase diagram has been proposed onto which various materials systems, e.g glasses or granular materials, can be mapped. We will discuss some recent applications of resonant and non-resonant soft X-ray Grazing Incidence Scattering to mesoscopic science, for example the study of magnetic domain wall fluctuations in thin films. For these studies, we use resonant magnetic x-ray scattering with a coherent photon beam and the technique of X-ray Photon Correlation Spectroscopy. find that at the ordering temperature the domains of an antiferromagnetic system, namely Dysprosium metal, behave very much also like a jammed system and their associated fluctuations exhibit behavior which exhibit some of the universal characteristics of jammed systems, such as non-exponential relaxation and Vogel-Fulcher type freezing. Work supported by Basic Energy Sciences, U.S. Dept. of Energy under Grant Number: DE-SC0003678.

Resonant Soft X-ray Scattering as a Powerful Probe of Buried Polymer Interfaces

NASA Astrophysics Data System (ADS)

Chen, Wei; Jiang, Zhang; Tirrell, Matthew

Elucidation of polymer interfacial structures provides insights into interfacial molecular mechanisms for coating protection, adhesion, lubrication, friction, wettability, biocompatibility, and even charge transport properties. Resonant Soft X-ray Scattering (RSoXS) offers a unique element, site and valence specific probe to study spatial modulations of molecular orbital degrees of freedom on the nanoscopic length scale. This unique sensitivity is achieved by merging small angle x-ray scattering and x-ray absorption spectroscopy into a single experiment, where the scattering provides information about spatial modulations and the spectroscopy provides sensitivity to the molecular anisotropy. Here we applied RSoXS to polystyrene (PS) films at solid-solid interfaces and poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) brushes at solid-liquid interfaces. It is found that the interfacial width of PS thin film is about one order of magnitude large than those observed by traditional scattering techniques. In addition, although the ion-induced changes of PMPC thickness are not apparent in aqueous solutions, their chain conformations like polyzwitterion distribution and correlation varied, dependent on salt types, ionic strengths and ion valences. Consequently, it is evident that RSoXS is a powerful probe of buried polymer interlaces with both spatial and chemical sensitivities. This work was supported by the U.S. Department of Energy, Office of Science, Program in Basic Energy Sciences, Division of Materials Science and Engineering.

Changes in conformational dynamics of basic side chains upon protein–DNA association

PubMed Central

Esadze, Alexandre; Chen, Chuanying; Zandarashvili, Levani; Roy, Sourav; Pettitt, B. Montgometry; Iwahara, Junji

2016-01-01

Basic side chains play major roles in recognition of nucleic acids by proteins. However, dynamic properties of these positively charged side chains are not well understood. In this work, we studied changes in conformational dynamics of basic side chains upon protein–DNA association for the zinc-finger protein Egr-1. By nuclear magnetic resonance (NMR) spectroscopy, we characterized the dynamics of all side-chain cationic groups in the free protein and in the complex with target DNA. Our NMR order parameters indicate that the arginine guanidino groups interacting with DNA bases are strongly immobilized, forming rigid interfaces. Despite the strong short-range electrostatic interactions, the majority of the basic side chains interacting with the DNA phosphates exhibited high mobility, forming dynamic interfaces. In particular, the lysine side-chain amino groups exhibited only small changes in the order parameters upon DNA-binding. We found a similar trend in the molecular dynamics (MD) simulations for the free Egr-1 and the Egr-1–DNA complex. Using the MD trajectories, we also analyzed side-chain conformational entropy. The interfacial arginine side chains exhibited substantial entropic loss upon binding to DNA, whereas the interfacial lysine side chains showed relatively small changes in conformational entropy. These data illustrate different dynamic characteristics of the interfacial arginine and lysine side chains. PMID:27288446

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.

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

Mechanism of intermediate filament recognition by plakin repeat domains revealed by envoplakin targeting of vimentin

NASA Astrophysics Data System (ADS)

Fogl, Claudia; Mohammed, Fiyaz; Al-Jassar, Caezar; Jeeves, Mark; Knowles, Timothy J.; Rodriguez-Zamora, Penelope; White, Scott A.; Odintsova, Elena; Overduin, Michael; Chidgey, Martyn

2016-03-01

Plakin proteins form critical connections between cell junctions and the cytoskeleton; their disruption within epithelial and cardiac muscle cells cause skin-blistering diseases and cardiomyopathies. Envoplakin has a single plakin repeat domain (PRD) which recognizes intermediate filaments through an unresolved mechanism. Herein we report the crystal structure of envoplakin's complete PRD fold, revealing binding determinants within its electropositive binding groove. Four of its five internal repeats recognize negatively charged patches within vimentin via five basic determinants that are identified by nuclear magnetic resonance spectroscopy. Mutations of the Lys1901 or Arg1914 binding determinants delocalize heterodimeric envoplakin from intracellular vimentin and keratin filaments in cultured cells. Recognition of vimentin is abolished when its residues Asp112 or Asp119 are mutated. The latter slot intermediate filament rods into basic PRD domain grooves through electrosteric complementarity in a widely applicable mechanism. Together this reveals how plakin family members form dynamic linkages with cytoskeletal frameworks.

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.

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

Broadband Acoustic Resonance Dissolution Spectroscopy (BARDS): A rapid test for enteric coating thickness and integrity of controlled release pellet formulations.

PubMed

Alfarsi, Anas; Dillon, Amy; McSweeney, Seán; Krüse, Jacob; Griffin, Brendan; Devine, Ken; Sherry, Patricia; Henken, Stephan; Fitzpatrick, Stephen; Fitzpatrick, Dara

2018-06-10

There are no rapid dissolution based tests for determining coating thickness, integrity and drug concentration in controlled release pellets either during production or post-production. The manufacture of pellets requires several coating steps depending on the formulation. The sub-coating and enteric coating steps typically take up to six hours each followed by additional drying steps. Post production regulatory dissolution testing also takes up to six hours to determine if the batch can be released for commercial sale. The thickness of the enteric coating is a key factor that determines the release rate of the drug in the gastro-intestinal tract. Also, the amount of drug per unit mass decreases with increasing thickness of the enteric coating. In this study, the coating process is tracked from start to finish on an hourly basis by taking samples of pellets during production and testing those using BARDS (Broadband Acoustic Resonance Dissolution Spectroscopy). BARDS offers a rapid approach to characterising enteric coatings with measurements based on reproducible changes in the compressibility of a solvent due to the evolution of air during dissolution. This is monitored acoustically via associated changes in the frequency of induced acoustic resonances. A steady state acoustic lag time is associated with the disintegration of the enteric coatings in basic solution. This lag time is pH dependent and is indicative of the rate at which the coating layer dissolves. BARDS represents a possible future surrogate test for conventional USP dissolution testing as its data correlates directly with the thickness of the enteric coating, its integrity and also with the drug loading as validated by HPLC. Copyright © 2018 Elsevier B.V. All rights reserved.

Conformation of the Phosphate D-alanine Zwitterion in Bacterial Teichoic Acid from Nuclear Magnetic Resonance Spectroscopy

PubMed Central

Garimella, Ravindranath; Halye, Jeffrey L.; Harrison, William; Klebba, Phillip E.; Rice, Charles V.

2009-01-01

The conformation of D-alanine (D-Ala) groups of bacterial teichoic acid is a central, yet untested, paradigm of microbiology. The D-Ala binds via the C-terminus, thereby allowing the amine to exist as a free cationic NH3+ group with the ability to form a contact-ion-pair with the nearby anionic phosphate group. This conformation hinders metal chelation by the phosphate because the zwitterion pair is charge neutral. To the contrary, the repulsion of cationic antimicrobial peptides (CAMPs) is attributed to the presence of the D-Ala cation; thus the ion-pair does not form in this model. Solid-state nuclear magnetic resonance (NMR) spectroscopy has been used to measure the distance between amine and phosphate groups within cell wall fragments of Bacillus subtilis. The bacteria were grown on media containing 15N D-Ala and β-chloroalanine racemase inhibitor. The rotational-echo double-resonance (REDOR) pulse sequence was used to measure the internuclear dipolar coupling and the results demonstrate: 1) the metal-free amine-to-phosphate distance is 4.4 Å and 2) the amine-to-phosphate distance increases to 5.4 Å in the presence of Mg2+ ions. As a result, the zwitterion exists in a nitrogen-oxygen ion-pair configuration providing teichoic acid with a positive charge to repel CAMPs. Additionally, the amine of D-Ala does not prevent magnesium chelation in contradiction to the prevailing view of teichoic acids in metal binding. Thus, the NMR-based description of teichoic acid structure resolves the contradictory models, advances the basic understanding of cell wall biochemistry, and provides possible insight into the creation of new antibiotic therapies. PMID:19746945

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…

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.

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

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

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.

Structure, crystallization and dielectric resonances in 2-13 GHz of waste-derived glass-ceramic

NASA Astrophysics Data System (ADS)

Yao, Rui; Liao, SongYi; Chen, XiaoYu; Wang, GuangRong; Zheng, Feng

2016-12-01

Structure, kinetics of crystallization, and dielectric resonances of waste-derived glass-ceramic prepared via quench-heating route were studied as a function of dosage of iron ore tailing (IOT) within 20-40 wt% using X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and vector network analyzer (VNA) measurements. The glass-ceramic mainly consisted of ferrite crystals embedded in borosilicate glass matrix. Crystallization kinetics and morphologies of ferrite crystals as well as coordination transformation of boron between [BO4] and [BO3] in glass network were adjustable by changing the amount of IOT. Dielectric resonances in 6-13 GHz were found to be dominated by oscillations of Ca2+ cations in glass network with [SiO4] units on their neighboring sites. Ni2+ ions made a small contribution to those resonances. Diopside formed when IOT exceeded 35 wt%, which led to weakening of the resonances.

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

Frequency-Comb Based Double-Quantum Two-Dimensional Spectrum Identifies Collective Hyperfine Resonances in Atomic Vapor Induced by Dipole-Dipole Interactions

NASA Astrophysics Data System (ADS)

Lomsadze, Bachana; Cundiff, Steven T.

2018-06-01

Frequency-comb based multidimensional coherent spectroscopy is a novel optical method that enables high-resolution measurement in a short acquisition time. The method's resolution makes multidimensional coherent spectroscopy relevant for atomic systems that have narrow resonances. We use double-quantum multidimensional coherent spectroscopy to reveal collective hyperfine resonances in rubidium vapor at 100 °C induced by dipole-dipole interactions. We observe tilted and elongated line shapes in the double-quantum 2D spectra, which have never been reported for Doppler-broadened systems. The elongated line shapes suggest that the signal is predominately from the interacting atoms that have a near zero relative velocity.

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.

Garry Rumbles | NREL

Science.gov Websites

, colloidal quantum dots, and single-walled carbon nanotubes. Laser-based experiments (time-resolved fluorescence spectroscopy; time-resolved resonance Raman spectroscopy; laser-induced fluorescence spectroscopy ; time-resolved evanescent wave-induced fluorescence spectroscopy; picosecond coherent anti-Stokes Raman

Microwave Spectroscopy of a Single Permalloy Chiral Metamolecule on a Coplanar Waveguide

NASA Astrophysics Data System (ADS)

Kodama, Toshiyuki; Kusanagi, Yusaku; Okamoto, Satoshi; Kikuchi, Nobuaki; Kitakami, Osamu; Tomita, Satoshi; Hosoito, Nobuyoshi; Yanagi, Hisao

2018-05-01

We investigate the microwave spectroscopies of a micrometer-sized single permalloy (Py) chiral structure on coplanar waveguides (CPWs). Under an external dc magnetic field applied in a direction perpendicular to the microwave propagation, the Py chiral structure loaded on the center of the CPW signal line shows Kittel-mode ferromagnetic resonance. Contrastingly, the structure on the signal-line edge highlights two additional resonances: spin-wave resonance at a higher frequency, and unique resonance at a lower frequency of approximately 7.8 GHz. The resonance signal at 7.8 GHz originates from magnetically induced, geometry-driven resonance, although the resonance frequency does not depend on the external magnetic field. Moreover, the displacement of the Py structures on the signal line results in nonreciprocal microwave transmission, which is traced back to the edge-guide mode.

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…

A Short History of Three Chemical Shifts

ERIC Educational Resources Information Center

Nagaoka, Shin-ichi

2007-01-01

A short history of chemical shifts in nuclear magnetic resonance (NMR), electron spectroscopy for chemical analysis (ESCA) and Mossbauer spectroscopy, which are useful for chemical studies, is described. The term chemical shift is shown to have originated in the mistaken assumption that nuclei of a given element would all undergo resonance at the…

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…

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…

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…

Raman scattering excitation spectroscopy of monolayer WS2.

PubMed

Molas, Maciej R; Nogajewski, Karol; Potemski, Marek; Babiński, Adam

2017-07-11

Resonant Raman scattering is investigated in monolayer WS 2 at low temperature with the aid of an unconventional technique, i.e., Raman scattering excitation (RSE) spectroscopy. The RSE spectrum is made up by sweeping the excitation energy, when the detection energy is fixed in resonance with excitonic transitions related to either neutral or charged excitons. We demonstrate that the shape of the RSE spectrum strongly depends on the selected detection energy. The resonance of outgoing light with the neutral exciton leads to an extremely rich RSE spectrum, which displays several Raman scattering features not reported so far, while no clear effect on the associated background photoluminescence is observed. Instead, when the outgoing photons resonate with the negatively charged exciton, a strong enhancement of the related emission occurs. Presented results show that the RSE spectroscopy can be a useful technique to study electron-phonon interactions in thin layers of transition metal dichalcogenides.

Plasmonic Circuit Theory for Multiresonant Light Funneling to a Single Spatial Hot Spot.

PubMed

Hughes, Tyler W; Fan, Shanhui

2016-09-14

We present a theoretical framework, based on plasmonic circuit models, for generating a multiresonant field intensity enhancement spectrum at a single "hot spot" in a plasmonic device. We introduce a circuit model, consisting of an array of coupled LC resonators, that directs current asymmetrically in the array, and we show that this circuit can funnel energy efficiently from each resonance to a single element. We implement the circuit model in a plasmonic nanostructure consisting of a series of metal bars of differing length, with nearest neighbor metal bars strongly coupled electromagnetically through air gaps. The resulting nanostructure resonantly traps different wavelengths of incident light in separate gap regions, yet it funnels the energy of different resonances to a common location, which is consistent with our circuit model. Our work is important for a number of applications of plasmonic nanoantennas in spectroscopy, such as in single-molecule fluorescence spectroscopy or Raman spectroscopy.

Computer Code for Interpreting 13C NMR Relaxation Measurements with Specific Models of Molecular Motion: The Rigid Isotropic and Symmetric Top Rotor Models and the Flexible Symmetric Top Rotor Model

DTIC Science & Technology

2017-01-01

unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT: Carbon-13 nuclear magnetic resonance (13C NMR) spectroscopy is a powerful technique for...FLEXIBLE SYMMETRIC TOP ROTOR MODEL 1. INTRODUCTION Nuclear magnetic resonance (NMR) spectroscopy is a tremendously powerful technique for...application of NMR spectroscopy concerns the property of molecular motion, which is related to many physical, and even biological, functions of molecules in

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.

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.

pH tunability and influence of alkali metal basicity on the plasmonic resonance of silver nanoparticles

NASA Astrophysics Data System (ADS)

Yadav, Vijay D.; Akhil Krishnan, R.; Borade, Lalit; Shirolikar, Seema; Jain, Ratnesh; Dandekar, Prajakta

2017-07-01

Localized surface plasmon resonance has been a unique and intriguing feature of silver nanoparticles (AgNPs) that has attracted immense attention. This has led to an array of applications for AgNPs in optics, sensors, plasmonic imaging etc. Although numerous applications have been reported consistently, the importance of buffer and reaction parameters during the synthesis of AgNPs, is still unclear. In the present study, we have demonstrated the influence of parameters like pH, temperature and buffer conditions (0.1 M citrate buffer) on the plasmonic resonance of AgNPs. We found that neutral and basic pH (from alkali metal) provide optimum interaction conditions for nucleation of plasmon resonant AgNPs. Interestingly, this was not observed in the non-alkali metal base (ammonia). Also, when the nanoparticles synthesized from alkali metal base were incorporated in different buffers, it was observed that the nanoparticles dissolved in the acidic buffer and had reduced plasmonic resonance intensity. This, however, was resolved in the basic buffer, increasing the plasmonic resonance intensity and confirming that nucleation of nanoparticles required basic conditions. The above inference has been supported by characterization of AgNPs using UV-Vis spectrophotometer, Fluorimetry analysis, Infrared spectrometer and TEM analysis. The study concluded that the plasmonic resonance of AgNPs occurs due to the interaction of alkali (Na) and transition metal (Ag) salt in basic/neutral conditions, at a specific temperature range, in presence of a capping agent (citric acid), providing a pH tune to the overall system.

Formalization, equivalence and generalization of basic resonance electrical circuits

NASA Astrophysics Data System (ADS)

Penev, Dimitar; Arnaudov, Dimitar; Hinov, Nikolay

2017-12-01

In the work are presented basic resonance circuits, which are used in resonance energy converters. The following resonant circuits are considered: serial, serial with parallel load parallel capacitor, parallel and parallel with serial loaded inductance. For the circuits under consideration, expressions are generated for the frequencies of own oscillations and for the equivalence of the active power emitted in the load. Mathematical expressions are graphically constructed and verified using computer simulations. The results obtained are used in the model based design of resonant energy converters with DC or AC output. This guaranteed the output indicators of power electronic devices.

Forster Resonance Energy Transfer and Conformational Stability of Proteins: An Advanced Biophysical Module for Physical Chemistry Students

ERIC Educational Resources Information Center

Sanchez, Katheryn M.; Schlamadinger, Diana E.; Gable, Jonathan E.; Kim, Judy E.

2008-01-01

Protein folding is an exploding area of research in biophysics and physical chemistry. Here, we describe the integration of several techniques, including absorption spectroscopy, fluorescence spectroscopy, and Forster resonance energy transfer (FRET) measurements, to probe important topics in protein folding. Cytochrome c is used as a model…

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...

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.

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.

MEMS-Based Force-Detected Nuclear Magnetic Resonance (FDNMR) Spectrometer

NASA Technical Reports Server (NTRS)

Lee, Choonsup; Butler, Mark C.; Elgammal, Ramez A.; George, Thomas; Hunt, Brian; Weitekamp, Daniel P.

2006-01-01

Nuclear Magnetic Resonance (NMR) spectroscopy allows assignment of molecular structure by acquiring the energy spectrum of nuclear spins in a molecule, and by interpreting the symmetry and positions of resonance lines in the spectrum. As such, NMR has become one of the most versatile and ubiquitous spectroscopic methods. Despite these tremendous successes, NMR experiments suffer from inherent low sensitivity due to the relatively low energy of photons in the radio frequency (rt) region of the electromagnetic spectrum. Here, we describe a high-resolution spectroscopy in samples with diameters in the micron range and below. We have reported design and fabrication of force-detected nuclear magnetic resonance (FDNMR).

What Can Be Learned from Nuclear Resonance Vibrational Spectroscopy: Vibrational Dynamics and Hemes

PubMed Central

2017-01-01

Nuclear resonance vibrational spectroscopy (NRVS; also known as nuclear inelastic scattering, NIS) is a synchrotron-based method that reveals the full spectrum of vibrational dynamics for Mössbauer nuclei. Another major advantage, in addition to its completeness (no arbitrary optical selection rules), is the unique selectivity of NRVS. The basics of this recently developed technique are first introduced with descriptions of the experimental requirements and data analysis including the details of mode assignments. We discuss the use of NRVS to probe 57Fe at the center of heme and heme protein derivatives yielding the vibrational density of states for the iron. The application to derivatives with diatomic ligands (O2, NO, CO, CN–) shows the strong capabilities of identifying mode character. The availability of the complete vibrational spectrum of iron allows the identification of modes not available by other techniques. This permits the correlation of frequency with other physical properties. A significant example is the correlation we find between the Fe–Im stretch in six-coordinate Fe(XO) hemes and the trans Fe–N(Im) bond distance, not possible previously. NRVS also provides uniquely quantitative insight into the dynamics of the iron. For example, it provides a model-independent means of characterizing the strength of iron coordination. Prediction of the temperature-dependent mean-squared displacement from NRVS measurements yields a vibrational “baseline” for Fe dynamics that can be compared with results from techniques that probe longer time scales to yield quantitative insights into additional dynamical processes. PMID:28921972

Ultrafast-based projection-reconstruction three-dimensional nuclear magnetic resonance spectroscopy.

PubMed

Mishkovsky, Mor; Kupce, Eriks; Frydman, Lucio

2007-07-21

Recent years have witnessed increased efforts toward the accelerated acquisition of multidimensional nuclear magnetic resonance (nD NMR) spectra. Among the methods proposed to speed up these NMR experiments is "projection reconstruction," a scheme based on the acquisition of a reduced number of two-dimensional (2D) NMR data sets constituting cross sections of the nD time domain being sought. Another proposition involves "ultrafast" spectroscopy, capable of completing nD NMR acquisitions within a single scan. Potential limitations of these approaches include the need for a relatively slow 2D-type serial data collection procedure in the former case, and a need for at least n high-performance, linearly independent gradients and a sufficiently high sensitivity in the latter. The present study introduces a new scheme that comes to address these limitations, by combining the basic features of the projection reconstruction and the ultrafast approaches into a single, unified nD NMR experiment. In the resulting method each member within the series of 2D cross sections required by projection reconstruction to deliver the nD NMR spectrum being sought, is acquired within a single scan with the aid of the 2D ultrafast protocol. Full nD NMR spectra can thus become available by backprojecting a small number of 2D sets, collected using a minimum number of scans. Principles, opportunities, and limitations of the resulting approach, together with demonstrations of its practical advantages, are here discussed and illustrated with a series of three-dimensional homo- and heteronuclear NMR correlation experiments.

Changes in conformational dynamics of basic side chains upon protein-DNA association.

PubMed

Esadze, Alexandre; Chen, Chuanying; Zandarashvili, Levani; Roy, Sourav; Pettitt, B Montgometry; Iwahara, Junji

2016-08-19

Basic side chains play major roles in recognition of nucleic acids by proteins. However, dynamic properties of these positively charged side chains are not well understood. In this work, we studied changes in conformational dynamics of basic side chains upon protein-DNA association for the zinc-finger protein Egr-1. By nuclear magnetic resonance (NMR) spectroscopy, we characterized the dynamics of all side-chain cationic groups in the free protein and in the complex with target DNA. Our NMR order parameters indicate that the arginine guanidino groups interacting with DNA bases are strongly immobilized, forming rigid interfaces. Despite the strong short-range electrostatic interactions, the majority of the basic side chains interacting with the DNA phosphates exhibited high mobility, forming dynamic interfaces. In particular, the lysine side-chain amino groups exhibited only small changes in the order parameters upon DNA-binding. We found a similar trend in the molecular dynamics (MD) simulations for the free Egr-1 and the Egr-1-DNA complex. Using the MD trajectories, we also analyzed side-chain conformational entropy. The interfacial arginine side chains exhibited substantial entropic loss upon binding to DNA, whereas the interfacial lysine side chains showed relatively small changes in conformational entropy. These data illustrate different dynamic characteristics of the interfacial arginine and lysine side chains. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Correlating structural dynamics and catalytic activity of AgAu nanoparticles with ultrafast spectroscopy and all-atom molecular dynamics simulations.

PubMed

Ferbonink, G F; Rodrigues, T S; Dos Santos, D P; Camargo, P H C; Albuquerque, R Q; Nome, R A

2018-05-29

In this study, we investigated hollow AgAu nanoparticles with the goal of improving our understanding of the composition-dependent catalytic activity of these nanoparticles. AgAu nanoparticles were synthesized via the galvanic replacement method with controlled size and nanoparticle compositions. We studied extinction spectra with UV-Vis spectroscopy and simulations based on Mie theory and the boundary element method, and ultrafast spectroscopy measurements to characterize decay constants and the overall energy transfer dynamics as a function of AgAu composition. Electron-phonon coupling times for each composition were obtained from pump-power dependent pump-probe transients. These spectroscopic studies showed how nanoscale surface segregation, hollow interiors and porosity affect the surface plasmon resonance wavelength and fundamental electron-phonon coupling times. Analysis of the spectroscopic data was used to correlate electron-phonon coupling times to AgAu composition, and thus to surface segregation and catalytic activity. We have performed all-atom molecular dynamics simulations of model hollow AgAu core-shell nanoparticles to characterize nanoparticle stability and equilibrium structures, besides providing atomic level views of nanoparticle surface segregation. Overall, the basic atomistic and electron-lattice dynamics of core-shell AgAu nanoparticles characterized here thus aid the mechanistic understanding and performance optimization of AgAu nanoparticle catalysts.

Silicon photon-counting avalanche diodes for single-molecule fluorescence spectroscopy

PubMed Central

Michalet, Xavier; Ingargiola, Antonino; Colyer, Ryan A.; Scalia, Giuseppe; Weiss, Shimon; Maccagnani, Piera; Gulinatti, Angelo; Rech, Ivan; Ghioni, Massimo

2014-01-01

Solution-based single-molecule fluorescence spectroscopy is a powerful experimental tool with applications in cell biology, biochemistry and biophysics. The basic feature of this technique is to excite and collect light from a very small volume and work in a low concentration regime resulting in rare burst-like events corresponding to the transit of a single molecule. Detecting photon bursts is a challenging task: the small number of emitted photons in each burst calls for high detector sensitivity. Bursts are very brief, requiring detectors with fast response time and capable of sustaining high count rates. Finally, many bursts need to be accumulated to achieve proper statistical accuracy, resulting in long measurement time unless parallelization strategies are implemented to speed up data acquisition. In this paper we will show that silicon single-photon avalanche diodes (SPADs) best meet the needs of single-molecule detection. We will review the key SPAD parameters and highlight the issues to be addressed in their design, fabrication and operation. After surveying the state-of-the-art SPAD technologies, we will describe our recent progress towards increasing the throughput of single-molecule fluorescence spectroscopy in solution using parallel arrays of SPADs. The potential of this approach is illustrated with single-molecule Förster resonance energy transfer measurements. PMID:25309114

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

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.

Structures and functions of proteins and nucleic acids in protein biosynthesis

NASA Astrophysics Data System (ADS)

Miyazawa, Tatsuo; Yokoyama, Shigeyuki

Infrared and Raman spectroscopy is useful for studying helical conformations of polypeptides, which are determined by molecular structure parameters. Nuclear magnetic resonance spectroscopy, as well as X-ray analysis, is now established to be important for conformation studies of proteins and nucleic acids in solution. This article is mainly concerned with the conformational aspect and function regulation in protein biosynthesis. The strict recognition of transfer ribonucleic acid (tRNA) by aminoacyl-tRNA synthetase (ARS) is achieved by multi-step mutual adaptation. The conformations of ARS-bound amino acids have been elucidated by transferred nuclear Overhauser effect analysis. Aminoacyl-tRNA takes the 3‧-isomeric form in the polypeptide chain elongation cycle. The regulation of codon recognition by post-transcriptional modification is achieved by conversion of the conformational characteristic of the anticodon of tRNA. The cytidine → lysidine modification of the anticodon of minor isoleucine tRNA concurrently converts the amino acid specificity and the codon specificity. As novel protein engineering, a basic strategy has been established for in vivo biosynthesis of proteins that are substituted with unnatural amino acids (alloproteins).

Miniature thermo-electric cooled cryogenic pump

DOEpatents

Keville, R.F.

1997-11-18

A miniature thermo-electric cooled cryogenic pump is described for removing residual water molecules from an inlet sample prior to sample analysis in a mass spectroscopy system, such as ion cyclotron resonance (ICR) mass spectroscopy. The cryogenic pump is a battery operated, low power (<1.6 watts) pump with a {Delta}T=100 C characteristic. The pump operates under vacuum pressures of 5{times}10{sup {minus}4} Torr to ultra high vacuum (UHV) conditions in the range of 1{times}10{sup {minus}7} to 3{times}10{sup {minus}9} Torr and will typically remove partial pressure, 2{times}10{sup {minus}7} Torr, residual water vapor. The cryogenic pump basically consists of an inlet flange piece, a copper heat sink with a square internal bore, four two tier Peltier (TEC) chips, a copper low temperature square cross sectional tubulation, an electronic receptacle, and an exit flange piece, with the low temperature tubulation being retained in the heat sink at a bias angle of 5{degree}, and with the TECs being positioned in parallel to each other with a positive potential being applied to the top tier thereof. 2 figs.

Miniature thermo-electric cooled cryogenic pump

DOEpatents

Keville, Robert F.

1997-01-01

A miniature thermo-electric cooled cryogenic pump for removing residual water molecules from an inlet sample prior to sample analysis in a mass spectroscopy system, such as ion cyclotron resonance (ICR) mass spectroscopy. The cryogenic pump is a battery operated, low power (<1.6 watts) pump with a .DELTA.T=100.degree. C. characteristic. The pump operates under vacuum pressures of 5.times.10.sup.-4 Torr to ultra high vacuum (UHV) conditions in the range of 1.times.10.sup.-7 to 3.times.10.sup.-9 Torr and will typically remove partial pressure, 2.times.10.sup.-7 Torr, residual water vapor. The cryogenic pump basically consists of an inlet flange piece, a copper heat sink with a square internal bore, four two tier Peltier (TEC) chips, a copper low temperature square cross sectional tubulation, an electronic receptacle, and an exit flange piece, with the low temperature tubulation being retained in the heat sink at a bias angle of 5.degree., and with the TECs being positioned in parallel to each other with a positive potential being applied to the top tier thereof.

Active sites of two orthologous cytochromes P450 2E1: Differences revealed by spectroscopic methods

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

Anzenbacherova, Eva; Hudecek, Jiri; Murgida, Daniel

2005-12-09

Cytochromes P450 2E1 of human and minipig origin were examined by absorption spectroscopy under high hydrostatic pressure and by resonance Raman spectroscopy. Human enzyme tends to denature to the P420 form more easily than the minipig form; moreover, the apparent compressibility of the heme active site (as judged from a redshift of the absorption maximum with pressure) is greater than that of the minipig counterpart. Relative compactness of the minipig enzyme is also seen in the Raman spectra, where the presence of planar heme conformation was inferred from band positions characteristic of the low-spin heme with high degree of symmetry.more » In this respect, the CYP2E1 seems to be another example of P450 conformational heterogeneity as shown, e.g., by Davydov et al. for CYP3A4 [Biochem. Biophys. Res. Commun. 312 (2003) 121-130]. The results indicate that the flexibility of the CYP active site is likely one of its basic structural characteristics.« less

Brain MR Spectroscopy Biomarkers in a Clinical Trial of PTS Patients With Comorbid AUD

DTIC Science & Technology

2016-05-01

levels in the neocortex of 40 alcohol dependent veterans with posttraumatic stress disorder (PTSD). We propose to perform longitudinal proton magnetic...longitudinal, magnetic resonance spectroscopy, alcohol dependence, posttraumatic stress disorder (PTSD), topiramate, γ-aminobutyric acid (GABA), glutamate, US...the neocortex of alcohol dependent veterans with posttraumatic stress disorder (PTSD). We propose to perform longitudinal proton magnetic resonance

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.

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…

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.

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.

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.

PITCH-ANGLE SCATTERING: RESONANCE VERSUS NONRESONANCE, A BASIC TEST OF THE QUASILINEAR DIFFUSIVE RESULT

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

Ragot, B. R.

2012-01-01

Due to the very broad range of the scales available for the development of turbulence in space and astrophysical plasmas, the energy at the resonant scales of wave-particle interaction often constitutes only a tiny fraction of the total magnetic turbulent energy. Despite the high efficiency of resonant wave-particle interaction, one may therefore question whether resonant interaction really is the determining interaction process between particles and turbulent fields. By evaluating and comparing resonant and nonresonant effects in the frame of a quasilinear calculation, the dominance of resonance is here put to the test. By doing so, a basic test of themore » classical resonant quasilinear diffusive result for the pitch-angle scattering of charged energetic particles is also performed.« less

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

PubMed

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

2017-04-01

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

Simultaneous quantification of glutamate and glutamine by J-modulated spectroscopy at 3 Tesla.

PubMed

Zhang, Yan; Shen, Jun

2016-09-01

The echo time (TE) averaged spectrum is the one-dimensional (1D) cross-section of the J-resolved spectrum at J = 0. In multiecho TE-averaged spectroscopy, glutamate (Glu) is differentiated from glutamine (Gln) at 3 Tesla (T). This method, however, almost entirely suppresses Gln resonance lines around 2.35 ppm, leaving Gln undetermined. This study presents a novel method for quantifying both Glu and Gln using multi-echo spectral data. A 1D cross-section of J-resolved spectroscopy at J = 7.5 Hz-referred to as J-modulated spectroscopy-was developed to simultaneously quantify Glu and Gln levels in the human brain. The transverse relaxation times (T2 s) of metabolites were first determined using conventional TE-averaged spectroscopy with different starting echo time and then incorporated into the spectral model for fitting J-modulated data. Simulation and in vivo data showed that the resonance signals of Glu and Gln were clearly separated around 2.35 ppm in J-modulated spectroscopy. In the anterior cingulate cortex, both Glu and Gln levels were found to be significantly higher in gray matter than in white matter in healthy subjects (P < 10(-10) and < 10(-5) , respectively). Gln resonances can be clearly separated from Glu and N-acetyl-aspartate around 2.35 ppm using J-modulated spectroscopy. This method can be used to quantitatively measure Glu and Gln simultaneously at 3T. Magn Reson Med 76:725-732, 2016. Published 2015. This article is a U.S. Government work and is in the public domain in the USA. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

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

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.

Evidence for a "metabolically inactive" inorganic phosphate pool in adenosine triphosphate synthase reaction using localized 31P saturation transfer magnetic resonance spectroscopy in the rat brain at 11.7 T.

PubMed

Tiret, Brice; Brouillet, Emmanuel; Valette, Julien

2016-09-01

With the increased spectral resolution made possible at high fields, a second, smaller inorganic phosphate resonance can be resolved on (31)P magnetic resonance spectra in the rat brain. Saturation transfer was used to estimate de novo adenosine triphosphate synthesis reaction rate. While the main inorganic phosphate pool is used by adenosine triphosphate synthase, the second pool is inactive for this reaction. Accounting for this new pool may not only help us understand (31)P magnetic resonance spectroscopy metabolic profiles better but also better quantify adenosine triphosphate synthesis. © The Author(s) 2016.

Sputtered SiO2 as low acoustic impedance material for Bragg mirror fabrication in BAW resonators.

PubMed

Olivares, Jimena; Wegmann, Enrique; Capilla, José; Iborra, Enrique; Clement, Marta; Vergara, Lucía; Aigner, Robert

2010-01-01

In this paper we describe the procedure to sputter low acoustic impedance SiO(2) films to be used as a low acoustic impedance layer in Bragg mirrors for BAW resonators. The composition and structure of the material are assessed through infrared absorption spectroscopy. The acoustic properties of the films (mass density and sound velocity) are assessed through X-ray reflectometry and picosecond acoustic spectroscopy. A second measurement of the sound velocity is achieved through the analysis of the longitudinal lambda/2 resonance that appears in these silicon oxide films when used as uppermost layer of an acoustic reflector placed under an AlN-based resonator.

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.

Simple Fabrication of Gd(III)-DTPA-Nanodiamond Particles by Chemical Modification for Use as Magnetic Resonance Imaging (MRI) Contrast Agent

NASA Astrophysics Data System (ADS)

Nakamura, Takako; Ohana, Tsuguyori; Yabuno, Hajime; Kasai, Rumiko; Suzuki, Tetsuya; Hasebe, Terumitsu

2013-01-01

We have developed a simple and useful process for fabricating nanodiamond (ND) particles modified with an organogadolinium moiety by chemical modification for their use as a magnetic resonance imaging (MRI) contrast agent. The introduction of the organogadolinium moiety on the surface of the ND particles was performed by the condensation of ND and diethylenetriaminepentaacetic acid (DTPA) followed by treatment with GdCl3. The modified surfaces were evaluated by X-ray photoelectron spectroscopy, diffuse reflectance Fourier transform infrared spectroscopy, mass spectroscopy, and inductively coupled plasma atomic emission spectroscopy analyses. MRI experiments on the Gd-DTPA-ND particles indicated their high signal intensity on T1-weighted images.

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.

Resonant antenna probes for tip-enhanced infrared near-field microscopy.

PubMed

Huth, Florian; Chuvilin, Andrey; Schnell, Martin; Amenabar, Iban; Krutokhvostov, Roman; Lopatin, Sergei; Hillenbrand, Rainer

2013-03-13

We report the development of infrared-resonant antenna probes for tip-enhanced optical microscopy. We employ focused-ion-beam machining to fabricate high-aspect ratio gold cones, which replace the standard tip of a commercial Si-based atomic force microscopy cantilever. Calculations show large field enhancements at the tip apex due to geometrical antenna resonances in the cones, which can be precisely tuned throughout a broad spectral range from visible to terahertz frequencies by adjusting the cone length. Spectroscopic analysis of these probes by electron energy loss spectroscopy, Fourier transform infrared spectroscopy, and Fourier transform infrared near-field spectroscopy corroborates their functionality as resonant antennas and verifies the broad tunability. By employing the novel probes in a scattering-type near-field microscope and imaging a single tobacco mosaic virus (TMV), we experimentally demonstrate high-performance mid-infrared nanoimaging of molecular absorption. Our probes offer excellent perspectives for optical nanoimaging and nanospectroscopy, pushing the detection and resolution limits in many applications, including nanoscale infrared mapping of organic, molecular, and biological materials, nanocomposites, or nanodevices.

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

Physicochemical properties and solubility of alkyl-(2-hydroxyethyl)-dimethylammonium bromide.

PubMed

Domańska, Urszula; Bogel-Łukasik, Rafał

2005-06-23

Quaternary ammonium salts, which are precursors of ionic liquids, have been prepared from N,N-dimethylethanolamine as a substrate. The paper includes specific basic characterization of synthesized compounds via the following procedures: nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectra, water content, mass spectroscopy (MS) spectra, temperatures of decompositions, basic thermodynamic properties of pure ionic liquids (the melting point, enthalpy of fusion, enthalpy of solid-solid phase transition, glass transition), and the difference in the solute heat capacity between the liquid and solid at the melting temperature determined by differential scanning calorimetry (DSC). The (solid + liquid) phase equilibria of binary mixtures containing (quaternary ammonium salt + water, or + 1-octanol) has been measured by a dynamic method over wide range of temperatures, from 230 K to 560 K. These data were correlated by means of the UNIQUAC ASM and modified nonrandom two-liquid NRTL1 equations utilizing parameters derived from the (solid + liquid) equilibrium. The partition coefficient of ionic liquid in the 1-octanol/water binary system has been calculated from the solubility results. Experimental partition coefficients (log P) were negative at three temperatures.

Current neurology

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

Appel, S.H.

1988-01-01

The topics covered in this book include: Duchenne muscular dystrophy: DNA diagnosis in practice; Central nervous system magnetic resonance imaging; and Magnetic resonance spectroscopy of neurologic diseases.

Future prospects in dermatologic applications of lasers, nanotechnology, and other new technologies.

PubMed

Boixeda, P; Feltes, F; Santiago, J L; Paoli, J

2015-04-01

We review novel technologies with diagnostic and therapeutic applications in dermatology. Among the diagnostic techniques that promise to become part of dermatologic practice in the future are optical coherence tomography, multiphoton laser scanning microscopy, Raman spectroscopy, thermography, and 7-T magnetic resonance imaging. Advances in therapy include novel light-based treatments, such as those applying lasers to new targets and in new wavelengths. Devices for home therapy are also appearing. We comment on the therapeutic uses of plasma, ultrasound, radiofrequency energy, total reflection amplification of spontaneous emission of radiation, light stimulation, and transepidermal drug delivery. Finally, we mention some basic developments in nanotechnology with prospects for future application in dermatology. Copyright © 2014 Elsevier España, S.L.U. and AEDV. All rights reserved.

Unraveling the chemical identity of meat pigments.

PubMed

Pegg, R B; Shahidi, F

1997-10-01

This review examines the chemistry of nitrite curing of meat and meat products as it relates to the development of cured meat color and provides a detailed account of how nitrite-free processed meats could be prepared using the preformed cooked cured-meat pigment (CCMP). Thus, a chemical description of meat color, both raw and cooked, and characterization of nitrosylheme pigments follows. Based on electron paramagnetic resonance (EPR), visible and infrared spectroscopic studies, evidence has been provided to support the hypothesis that the chemical structure of the preformed CCMP is identical to that of the pigment prepared in situ after thermal processing of nitrite-cured meat and is in fact a mononitrosylheme complex. An appendix, which describes the basic principles of EPR spectroscopy used in the context of this review, is attached.

Single-molecule spectroscopic methods.

PubMed

Haustein, Elke; Schwille, Petra

2004-10-01

Being praised for the mere fact of enabling the detection of individual fluorophores a dozen years ago, single-molecule techniques nowadays represent standard methods for the elucidation of the structural rearrangements of biologically relevant macromolecules. Single-molecule-sensitive techniques, such as fluorescence correlation spectroscopy, allow real-time access to a multitude of molecular parameters (e.g. diffusion coefficients, concentration and molecular interactions). As a result of various recent advances, this technique shows promise even for intracellular applications. Fluorescence imaging can reveal the spatial localization of fluorophores on nanometer length scales, whereas fluorescence resonance energy transfer supports a wide range of different applications, including real-time monitoring of conformational rearrangements (as in protein folding). Still in their infancy, single-molecule spectroscopic methods thus provide unprecedented insights into basic molecular mechanisms. Copyright 2004 Elsevier Ltd.

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.

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

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.

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.

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.

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

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.

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.

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

EIT Noise Resonance Power Broadening: a probe for coherence dynamics

NASA Astrophysics Data System (ADS)

Crescimanno, Michael; O'Leary, Shannon; Snider, Charles

2012-06-01

EIT noise correlation spectroscopy holds promise as a simple, robust method for performing high resolution spectroscopy used in devices as diverse as magnetometers and clocks. One useful feature of these noise correlation resonances is that they do not power broaden with the EIT window. We report on measurements of the eventual power broadening (at higher optical powers) of these resonances and a simple, quantitative theoretical model that relates the observed power broadening slope with processes such as two-photon detuning gradients and coherence diffusion. These processes reduce the ground state coherence relative to that of a homogeneous system, and thus the power broadening slope of the EIT noise correlation resonance may be a simple, useful probe for coherence dynamics.

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…

Nonlinear X-Ray and Auger Spectroscopy at X-Ray Free-Electron Laser Sources

NASA Astrophysics Data System (ADS)

Rohringer, Nina

2015-05-01

X-ray free-electron lasers (XFELs) open the pathway to transfer non-linear spectroscopic techniques to the x-ray domain. A promising all x-ray pump probe technique is based on coherent stimulated electronic x-ray Raman scattering, which was recently demonstrated in atomic neon. By tuning the XFEL pulse to core-excited resonances, a few seed photons in the spectral tail of the XFEL pulse drive an avalanche of resonant inelastic x-ray scattering events, resulting in exponential amplification of the scattering signal by of 6-7 orders of magnitude. Analysis of the line profile of the emitted radiation permits to demonstrate the cross over from amplified spontaneous emission to coherent stimulated resonance scattering. In combination with statistical covariance mapping, a high-resolution spectrum of the resonant inelastic scattering process can be obtained, opening the path to coherent stimulated x-ray Raman spectroscopy. An extension of these ideas to molecules and a realistic feasibility study of stimulated electronic x-ray Raman scattering in CO will be presented. Challenges to realizing stimulated electronic x-ray Raman scattering at present-day XFEL sources will be discussed, corroborated by results of a recent experiment at the LCLS XFEL. Due to the small gain cross section in molecular targets, other nonlinear spectroscopic techniques such as nonlinear Auger spectroscopy could become a powerful alternative. Theory predictions of a novel pump probe technique based on resonant nonlinear Auger spectroscopic will be discussed and the method will be compared to stimulated x-ray Raman 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

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

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

ERIC Educational Resources Information Center

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

2007-01-01

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

The Use and Evaluation of Scaffolding, Student Centered-Learning, Behaviorism, and Constructivism to Teach Nuclear Magnetic Resonance and IR Spectroscopy in a Two-Semester Organic Chemistry Course

ERIC Educational Resources Information Center

Livengood, Kimberly; Lewallen, Denver W.; Leatherman, Jennifer; Maxwell, Janet L.

2012-01-01

Since 2002, infrared spectroscopy (IR) and nuclear magnetic resonance (NMR) spectrometry have been introduced at the beginning of the first-semester organic chemistry lab course at this university. Starting in 2008, each individual student was given 20 unique homework problems that consisted of multiple-choice [superscript 1]H NMR and IR problems…

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]).…

Saturation spectroscopy of calcium atomic vapor in hot quartz cells with cold windows

NASA Astrophysics Data System (ADS)

Vilshanskaya, E. V.; Saakyan, S. A.; Sautenkov, V. A.; Murashkin, D. A.; Zelener, B. B.; Zelener, B. V.

2018-01-01

Saturation spectroscopy of calcium atomic vapor was performed in hot quartz cells with cold windows. The Doppler-free absorption resonances with spectral width near 50 MHz were observed. For these experiments and future applications long-lived quartz cells with buffer gas were designed and made. A cooling laser for calcium magneto-optical trap will be frequency locked to the saturation resonances in the long-lived cells.

[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.

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.

A General Quantum Mechanical Method to Predict Positron Spectroscopy

DTIC Science & Technology

2007-06-01

7 2.1 Positron Annihilation Spectroscopy . . . . . . . . . . . . . 7 2.1.1 Positron Transport and Annihilation in Condensed Matter...8 2.1.2 Traditional Positron Annihilation Spectroscopy . . 10 2.1.3 Vibrational Feshbach Resonances of Positrons with... positron annihilation lifetime spectroscopy system . . . 63 11. Tungsten positron lifetime spectrum . . . . . . . . . . . . . . . . . . 66 12. K2B12H12

Secular resonances. [of asteroidal dynamics

NASA Technical Reports Server (NTRS)

Scholl, H.; Froeschle, CH.; Kinoshita, H.; Yoshikawa, M.; Williams, J. G.

1989-01-01

Theories and numerical experiments regarding secular resonances are reviewed. The basic dynamics and the positions of secular resonances are discussed, and secular perturbation theories for the nu16 resonance case, the nu6 resonance, and the nu5 resonance are addressed. What numerical experiments have revealed about asteroids located in secular resonances, the stability of secular resonances, variations of eccentricities and inclinations, and chaotic orbits is considered. Resonant transport of meteorites is discussed.

Multi-photon ionization of atoms in intense short-wavelength radiation fields

NASA Astrophysics Data System (ADS)

Meyer, Michael

2015-05-01

The unprecedented characteristics of XUV and X-ray Free Electron Lasers (FELs) have stimulated numerous investigations focusing on the detailed understanding of fundamental photon-matter interactions in atoms and molecules. In particular, the high intensities (up to 106 W/cm2) giving rise to non-linear phenomena in the short wavelength regime. The basic phenomenology involves the production of highly charged ions via electron emission to which both sequential and direct multi-photon absorption processes contribute. The detailed investigation of the role and relative weight of these processes under different conditions (wavelength, pulse duration, intensity) is the key element for a comprehensive understanding of the ionization dynamics. Here the results of recent investigations are presented, performed at the FELs in Hamburg (FLASH) and Trieste (FERMI) on atomic systems with electronic structures of increasing complexity (Ar, Ne and Xe). Mainly, electron spectroscopy is used to obtain quantitative information about the relevance of various multi-photon ionization processes. For the case of Ar, a variety of processes including above threshold ionization (ATI) from 3p and 3s valence shells, direct 2p two-photon ionization and resonant 2p-4p two-photon excitations were observed and their role was quantitatively determined comparing the experimental ionization yields to ab-initio calculations of the cross sections for the multi-photon processes. Using Ar as a benchmark to prove the reliability of the combined experimental and theoretical approach, the more complex and intriguing case of Xe was studied. Especially, the analysis of the two-photon ATI from the Xe 4d shell reveals new insight into the character of the 4d giant resonance, which was unresolved in the linear one-photon regime. Finally, the influence of intense XUV radiation to the relaxation dynamics of the Ne 2s-3p resonance was investigated by angle-resolved electron spectroscopy, especially be observing the intensity dependent variation of the angular distribution patterns for the sequential ionization process.

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 are required before routine clinical use. Copyright 2004 John Wiley & Sons, Ltd.

Using Essential Oils to Teach Advanced-Level Organic Chemistry Separation Techniques and Spectroscopy

ERIC Educational Resources Information Center

Bott, Tina M.; Wan, Hayley

2013-01-01

Students sometimes have difficulty grasping the importance of when and how basic distillation techniques, column chromatography, TLC, and basic spectroscopy (IR and NMR) can be used to identify unknown compounds within a mixture. This two-part experiment uses mixtures of pleasant-smelling, readily available terpenoid compounds as unknowns to…

Surface plasmon resonance spectroscopy for characterisation of membrane protein-ligand interactions and its potential for drug discovery.

PubMed

Patching, Simon G

2014-01-01

Surface plasmon resonance (SPR) spectroscopy is a rapidly developing technique for the study of ligand binding interactions with membrane proteins, which are the major molecular targets for validated drugs and for current and foreseeable drug discovery. SPR is label-free and capable of measuring real-time quantitative binding affinities and kinetics for membrane proteins interacting with ligand molecules using relatively small quantities of materials and has potential to be medium-throughput. The conventional SPR technique requires one binding component to be immobilised on a sensor chip whilst the other binding component in solution is flowed over the sensor surface; a binding interaction is detected using an optical method that measures small changes in refractive index at the sensor surface. This review first describes the basic SPR experiment and the challenges that have to be considered for performing SPR experiments that measure membrane protein-ligand binding interactions, most importantly having the membrane protein in a lipid or detergent environment that retains its native structure and activity. It then describes a wide-range of membrane protein systems for which ligand binding interactions have been characterised using SPR, including the major drug targets G protein-coupled receptors, and how challenges have been overcome for achieving this. Finally it describes some recent advances in SPR-based technology and future potential of the technique to screen ligand binding in the discovery of drugs. This article is part of a Special Issue entitled: Structural and biophysical characterisation of membrane protein-ligand binding. Copyright © 2013 Elsevier B.V. All rights reserved.

Plasmon response evaluation based on image-derived arbitrary nanostructures.

PubMed

Trautmann, S; Richard-Lacroix, M; Dathe, A; Schneidewind, H; Dellith, J; Fritzsche, W; Deckert, V

2018-05-31

The optical response of realistic 3D plasmonic substrates composed of randomly shaped particles of different size and interparticle distance distributions in addition to nanometer scale surface roughness is intrinsically challenging to simulate due to computational limitations. Here, we present a Finite Element Method (FEM)-based methodology that bridges in-depth theoretical investigations and experimental optical response of plasmonic substrates composed of such silver nanoparticles. Parametrized scanning electron microscopy (SEM) images of surface enhanced Raman spectroscopy (SERS) active substrate and tip-enhanced Raman spectroscopy (TERS) probes are used to simulate the far-and near-field optical response. Far-field calculations are consistent with experimental dark field spectra and charge distribution images reveal for the first time in arbitrary structures the contributions of interparticle hybridized modes such as sub-radiant and super-radiant modes that also locally organize as basic units for Fano resonances. Near-field simulations expose the spatial position-dependent impact of hybridization on field enhancement. Simulations of representative sections of TERS tips are shown to exhibit the same unexpected coupling modes. Near-field simulations suggest that these modes can contribute up to 50% of the amplitude of the plasmon resonance at the tip apex but, interestingly, have a small effect on its frequency in the visible range. The band position is shown to be extremely sensitive to particle nanoscale roughness, highlighting the necessity to preserve detailed information at both the largest and the smallest scales. To the best of our knowledge, no currently available method enables reaching such a detailed description of large scale realistic 3D plasmonic systems.

The binding of manganese(II) and zinc(II) to the synthetic oligonucleotide d(C-G-C-G-A-A-T-T-C-G-C-G)2. A 1H NMR study.

PubMed

Frøystein, N A; Sletten, E

1991-03-01

The interaction of the synthetic oligonucleotide d(C-G-C-G-A-A-T-T-C-G-C-G)2 with two different transition-metal ions has been investigated in aqueous solution by means of 1H NMR spectroscopy. The effects on the DNA due to the presence of manganese(II) or zinc(II) have been monitored by observing the paramagnetic broadening and diamagnetic shifts of the non-exchangeable proton resonance lines, respectively. The 1H NMR spectra acquired during the course of the manganese(II) titration show very distinct broadening effects on certain DNA resonance lines. Primarily, the H8 resonance of G4 is affected, but also the H5 and H6 resonances of C3 are clearly affected by the metal. The results imply that the binding of manganese(II) to DNA is sequence specific. The 1H spectra obtained during the zinc(II) titration reveal diamagnetic shift effects which largely conform with the paramagnetic broadening effects due to the presence of manganese(II), although this picture is somewhat more complex. The H8 resonance of G4 displays a clearly visible high-field shift, while for the other guanosine H8 protons this effect is absent. The H1' and H2' protons of C3 show an effect of similar strength, although in the opposite direction, while H5 and H6 of C3 are only slightly affected. Local differences in the structure of the DNA and the basicities of potential binding sites on different base steps in the sequence might account for the observed sequence selectivity.

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.

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.

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.

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.

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.

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.

Ground-state IVR of jet-cooled p-alkylphenols and p-alkylanilines studied by stimulated emission ion dip and stimulated Raman-UV optical double-resonance spectroscopies

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

Ebata, T.; Ito, M.

1992-04-16

This paper reports the intramolecular vibrational redistribution (IVR) of the jet-cooled p-alkylphenols and p-alkylanilines in S{sub 0} state by using stimulated emission ion dip and stimulated raman-UV optical double-resonance spectroscopy. The IVR rate constants of several vibrational levels localized in the benzene ring are estimated. 31 refs., 12 figs., 4 tabs.

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.

Combined electron energy-loss and cathodoluminescence spectroscopy on individual and composite plasmonic nanostructures

NASA Astrophysics Data System (ADS)

Coenen, Toon; Schoen, David T.; Brenny, Benjamin J. M.; Polman, Albert; Brongersma, Mark L.

2016-05-01

We systematically investigate the plasmonic "dolmen" geometry and its constituent elements using electron energy-loss spectroscopy and cathodoluminescence spectroscopy. In particular, we study the effects of the particle size and spacing on the resonant behavior and interparticle coupling. Because we apply both techniques on the same structures we can directly compare the results and investigate the radiative versus nonradiative character of the different modes. We find that the cathodoluminescence response is significantly lower than the electron energy-loss response for higher-energy modes because strong absorption reduces the scattering efficiency in this regime. Furthermore, we show that the overall resonant response roughly scales with size as expected for plasmonic structures but that the transverse resonant modes do become more dominant in larger structures due to a relative reduction in Ohmic dissipation. Using EELS and CL we can rigorously study coupling between the elements and show that the coupling diminishes for larger spacings.

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.

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.

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.

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.

Magnetic Field Gradient Calibration as an Experiment to Illustrate Magnetic Resonance Imaging

ERIC Educational Resources Information Center

Seedhouse, Steven J.; Hoffmann, Markus M.

2008-01-01

A nuclear magnetic resonance (NMR) spectroscopy experiment for the undergraduate physical chemistry laboratory is described that encompasses both qualitative and quantitative pedagogical goals. Qualitatively, the experiment illustrates how images are obtained in magnetic resonance imaging (MRI). Quantitatively, students experience the…

The interaction of 2-mercaptobenzimidazole with human serum albumin as determined by spectroscopy, atomic force microscopy and molecular modeling.

PubMed

Li, Yuqin; Jia, Baoxiu; Wang, Hao; Li, Nana; Chen, Gaopan; Lin, Yuejuan; Gao, Wenhua

2013-04-01

The interaction of 2-mercaptobenzimidazole (MBI) with human serum albumin (HSA) was studied in vitro by equilibrium dialysis under normal physiological conditions. This study used fluorescence, ultraviolet-visible spectroscopy (UV-vis), Fourier transform infrared (FT-IR), circular dichroism (CD) and Raman spectroscopy, atomic force microscopy (AFM) and molecular modeling techniques. Association constants, the number of binding sites and basic thermodynamic parameters were used to investigate the quenching mechanism. Based on the fluorescence resonance energy transfer, the distance between the HSA and MBI was 2.495 nm. The ΔG(0), ΔH(0), and ΔS(0) values across temperature indicated that the hydrophobic interaction was the predominant binding Force. The UV, FT-IR, CD and Raman spectra confirmed that the HSA secondary structure was altered in the presence of MBI. In addition, the molecular modeling showed that the MBI-HSA complex was stabilized by hydrophobic forces, which resulted from amino acid residues. The AFM results revealed that the individual HSA molecule dimensions were larger after interaction with MBI. Overall, this study suggested a method for characterizing the weak intermolecular interaction. In addition, this method is potentially useful for elucidating the toxigenicity of MBI when it is combined with the biomolecular function effect, transmembrane transport, toxicological testing and other experiments. Copyright © 2012 Elsevier B.V. All rights reserved.

In vivo study on the biocompatibility of chitosan-hydroxyapatite film depending on degree of deacetylation.

PubMed

Jeong, Ki-Jae; Song, Younseong; Shin, Hye-Ri; Kim, Ji Eun; Kim, Jeonghyo; Sun, Fangfang; Hwang, Dae-Youn; Lee, Jaebeom

2017-06-01

Chitosan, produced from chitin, is one of the polymers with promising applications in various fields. However, despite diverse research studies conducted on its biocompatibility, its uses are still limited. The main reason is the degree of deacetylation (DOD), which represents the proportion of deacetylated units in the polymer and is directly correlated with its biocompatibility property. In this article, the in vivo biocompatibility of three chitosan-hydroxyapatite composite films composed of chitosan with different DOD values was investigated by traditional biological protocols and novel optical spectroscopic analyses. The DOD of the chitosan obtained from three different manufacturers was estimated and calculated by Raman spectroscopy, Fourier transform infrared spectroscopy, and proton nuclear magnetic resonance spectroscopy. The chitosan with the higher DOD induced a higher incidence of inflammation in skin cells. The amino group density, biodegradability, and crystallinity of chitosan are the three possible factors that need to be considered when determining the biocompatibility of the films for in vivo application, as they led to complicated biological results, resulting in either better or worse inflammation even when using chitosan products with the same DOD. This basic study on the relationship between the DOD and inflammation is valuable for the development of further chitosan-based researches. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1637-1645, 2017. © 2017 Wiley Periodicals, Inc.

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.

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.

Solid-State NMR Spectroscopy for the Physical Chemistry Laboratory

ERIC Educational Resources Information Center

Kinnun, Jacob J.; Leftin, Avigdor; Brown, Michael F.

2013-01-01

Solid-state nuclear magnetic resonance (NMR) spectroscopy finds growing application to inorganic and organic materials, biological samples, polymers, proteins, and cellular membranes. However, this technique is often neither included in laboratory curricula nor typically covered in undergraduate courses. On the other hand, spectroscopy and…

On the interpretation of continuous wave electron spin resonance spectra of tempo-palmitate in 5-cyanobiphenyl.

PubMed

Zerbetto, Mirco; Polimeno, Antonino; Cimino, Paola; Barone, Vincenzo

2008-01-14

Electron spin resonance (ESR) measurements are highly informative on the dynamic behavior of molecules, which is of fundamental importance to understand their stability, biological functions and activities, and catalytic action. The wealth of dynamic information which can be extracted from a continuous wave electron spin resonance (cw-ESR) spectrum can be inferred by a basic theoretical approach defined within the stochastic Liouville equation formalism, i.e., the direct inclusion of motional dynamics in the form of stochastic (Fokker-Planck/diffusive) operators in the super Hamiltonian H governing the time evolution of the system. Modeling requires the characterization of magnetic parameters (e.g., hyperfine and Zeeman tensors) and the calculation of ESR observables in terms of spectral densities. The magnetic observables can be pursued by the employment of density functional theory which is apt, provided that hybrid functionals are employed, for the accurate computation of structural properties of molecular systems. Recently, an ab initio integrated computational approach to the in silico interpretation of cw-ESR spectra of multilabeled systems in isotropic fluids has been discussed. In this work we present the extension to the case of nematic liquid crystalline environments by performing simulations of the ESR spectra of the prototypical nitroxide probe 4-(hexadecanoyloxy)-2,2,6,6-tetramethylpiperidine-1-oxy in isotropic and nematic phases of 5-cyanobiphenyl. We first discuss the basic ingredients of the integrated approach, i.e., (1) determination of geometric and local magnetic parameters by quantum-mechanical calculations, taking into account the solvent and, when needed, the vibrational averaging contributions; (2) numerical solution of a stochastic Liouville equation in the presence of diffusive rotational dynamics, based on (3) parameterization of diffusion rotational tensor provided by a hydrodynamic model. Next we present simulated spectra with minimal resorting to fitting procedures, proving that the combination of sensitive ESR spectroscopy and sophisticated modeling can be highly helpful in providing three-dimensional structural and dynamic information on molecular systems in anisotropic environments.

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.

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)

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

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.

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.

Resistive spectroscopy coupled with non-contacting oscillator for detecting discontinuous-continuous transition of metallic films

NASA Astrophysics Data System (ADS)

Nakamura, N.; Ogi, H.

2017-09-01

In spectroscopic measurements, one measures responses of specimens to oscillating fields (including electric, magnetic, and stress fields) at different frequencies for characterizing the samples. In contrast, we develop spectroscopy where the response (loss) is measured by changing the electric resistance, named the resistive spectroscopy. In the resistive spectroscopy, an energy-loss peak appears when the resistance is changed. We here apply it for studying the morphological change of thin films. When a metallic material is deposited on a substrate, the morphological transition from discontinuous islands to the continuous film occurs. It accompanies a drastic change in the resistance of the deposited material because of the transition from an insulator to a conductor. We find that the energy-loss peak appears at the transition moment during deposition of Ag. The resistive spectroscopy we develop uses no electrodes; it adopts the electric field generated by a piezoelectric material vibrating at its resonant frequency beneath the substrate. It is observed that the full width at half maximum (FWHM) of the resonance shows the peak during the deposition for high resistance substrates. The FWHM peak fails to be found for low resistance substrates, but it appears when the resonance frequency is increased. We propose an electrical-circuit model for explaining these observations.

In vivo two-dimensional NMR correlation spectroscopy

NASA Astrophysics Data System (ADS)

Kraft, Robert A.

1999-10-01

The poor resolution of in-vivo one- dimensional nuclear magnetic resonance spectroscopy (NMR) has limited its clinical potential. Currently, only the large singlet methyl resonances arising from N-acetyl aspartate (NAA), choline, and creatine are quantitated in a clinical setting. Other metabolites such as myo- inositol, glutamine, glutamate, lactate, and γ- amino butyric acid (GABA) are of clinical interest but quantitation is difficult due to the overlapping resonances and limited spectral resolution. To improve the spectral resolution and distinguish between overlapping resonances, a series of two- dimensional chemical shift correlation spectroscopy experiments were developed for a 1.5 Tesla clinical imaging magnet. Two-dimensional methods are attractive for in vivo spectroscopy due to their ability to unravel overlapping resonances with the second dimension, simplifying the interpretation and quantitation of low field NMR spectra. Two-dimensional experiments acquired with mix-mode line shape negate the advantages of the second dimension. For this reason, a new experiment, REVOLT, was developed to achieve absorptive mode line shape in both dimensions. Absorptive mode experiments were compared to mixed mode experiments with respect to sensitivity, resolution, and water suppression. Detailed theoretical and experimental calculations of the optimum spin lock and radio frequency power deposition were performed. Two-dimensional spectra were acquired from human bone marrow and human brain tissue. The human brain tissue spectra clearly reveal correlations among the coupled spins of NAA, glutamine, glutamate, lactate, GABA, aspartate and myo-inositol obtained from a single experiment of 23 minutes from a volume of 59 mL. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

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

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.

Preparation and Evaluation of the Chelating Nanocomposite Fabricated with Marine Algae Schizochytrium sp. Protein Hydrolysate and Calcium.

PubMed

Lin, Jiaping; Cai, Xixi; Tang, Mengru; Wang, Shaoyun

2015-11-11

Marine algae have been becoming a popular research topic because of their biological implication. The algae peptide-based metal-chelating complex was investigated in this study. Schizochytrium sp. protein hydrolysate (SPH) possessing high Ca-binding capacity was prepared through stepwise enzymatic hydrolysis to a degree of hydrolysis of 22.46%. The nanocomposites of SPH chelated with calcium ions were fabricated in aqueous solution at pH 6 and 30 °C for 20 min, with the ratio of SPH to calcium 3:1 (w/w). The size distribution showed that the nanocomposite had compact structure with a radius of 68.16 ± 0.50 nm. SPH was rich in acidic amino acids, accounting for 33.55%, which are liable to bind with calcium ions. The molecular mass distribution demonstrated that the molecular mass of SPH was principally concentrated at 180-2000 Da. UV scanning spectroscopy and Fourier transform infrared spectroscopy suggested that the primary sites of calcium-binding corresponded to the carboxyl groups, carbonyl groups, and amino groups of SPH. The results of fluorescent spectroscopy, size distribution, atomic force microscope, and (1)H nuclear magnetic resonance spectroscopy suggested that calcium ions chelated with SPH would cause intramolecular and intermolecular folding and aggregating. The SPH-calcium chelate exerted remarkable stability and absorbability under either acidic or basic conditions, which was in favor of calcium absorption in the gastrointestinal tracts of humans. The investigation suggests that SPH-calcium chelate has the potential prospect to be utilized as a nutraceutical supplement to improve bone health in the human body.

Interactions between glutamate, dopamine, and the neuronal signature of response inhibition in the human striatum.

PubMed

Lorenz, Robert C; Gleich, Tobias; Buchert, Ralph; Schlagenhauf, Florian; Kühn, Simone; Gallinat, Jürgen

2015-10-01

Response inhibition is a basic mechanism in cognitive control and dysfunctional in major psychiatric disorders. The neuronal mechanisms are in part driven by dopamine in the striatum. Animal data suggest a regulatory role of glutamate on the level of the striatum. We used a trimodal imaging procedure of the human striatum including F18-DOPA positron emission tomography, proton magnetic resonance spectroscopy, and functional magnetic resonance imaging of a stop signal task. We investigated dopamine synthesis capacity and glutamate concentration in vivo and their relation to functional properties of response inhibition. A mediation analysis revealed a significant positive association between dopamine synthesis capacity and inhibition-related neural activity in the caudate nucleus. This relationship was significantly mediated by striatal glutamate concentration. Furthermore, stop signal reaction time was inversely related to striatal activity during inhibition. The data show, for the first time in humans, an interaction between dopamine, glutamate, and the neural signature of response inhibition in the striatum. This finding stresses the importance of the dopamine-glutamate interaction for behavior and may facilitate the understanding of psychiatric disorders characterized by impaired response inhibition. © 2015 Wiley Periodicals, Inc.

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

Infrared/Terahertz Double Resonance for Chemical Remote Sensing: Signatures and Performance Predictions

DTIC Science & Technology

2011-01-01

remote sensing , such as Fourier-transform infrared spectroscopy, has limited recognition specificity because of atmospheric pressure broadening. Active interrogation techniques promise much greater chemical recognition that can overcome the limits imposed by atmospheric pressure broadening. Here we introduce infrared - terahertz (IR/THz) double resonance spectroscopy as an active means of chemical remote sensing that retains recognition specificity through rare, molecule-unique coincidences between IR molecular absorption and a line-tunable CO2

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.

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.

Microbial interactions with chromium: basic biological processes and applications in environmental biotechnology.

PubMed

Gutiérrez-Corona, J F; Romo-Rodríguez, P; Santos-Escobar, F; Espino-Saldaña, A E; Hernández-Escoto, H

2016-12-01

Chromium (Cr) is a highly toxic metal for microorganisms as well as plants and animal cells. Due to its widespread industrial use, Cr has become a serious pollutant in diverse environmental settings. The hexavalent form of the metal, Cr(VI), is considered a more toxic species than the relatively innocuous and less mobile Cr(III) form. The study of the interactions between microorganisms and Cr has been helpful to unravel the mechanisms allowing organisms to survive in the presence of high concentrations of Cr(VI) and to detoxify and remove the oxyanion. Various mechanisms of interactions with Cr have been identified in diverse species of bacteria and fungi, including biosorption, bioaccumulation, reduction of Cr(VI) to Cr(III), and chromate efflux. Some of these systems have been proposed as potential biotechnological tools for the bioremediation of Cr pollution using bioreactors or by in situ treatments. In this review, the interactions of microorganisms with Cr are summarised, emphasising the importance of new research avenues using advanced methodologies, including proteomic, transcriptomic, and metabolomic analyses, as well as the use of techniques based on X-ray absorption spectroscopy and electron paramagnetic resonance spectroscopy.

21 CFR 892.1000 - Magnetic resonance diagnostic device.

Code of Federal Regulations, 2010 CFR

2010-04-01

... parameters derived from the images and/or spectra may also be produced. The device includes hydrogen-1 (proton) imaging, sodium-23 imaging, hydrogen-1 spectroscopy, phosphorus-31 spectroscopy, and chemical...

21 CFR 892.1000 - Magnetic resonance diagnostic device.

Code of Federal Regulations, 2012 CFR

2012-04-01

... parameters derived from the images and/or spectra may also be produced. The device includes hydrogen-1 (proton) imaging, sodium-23 imaging, hydrogen-1 spectroscopy, phosphorus-31 spectroscopy, and chemical...

21 CFR 892.1000 - Magnetic resonance diagnostic device.

Code of Federal Regulations, 2011 CFR

2011-04-01

... parameters derived from the images and/or spectra may also be produced. The device includes hydrogen-1 (proton) imaging, sodium-23 imaging, hydrogen-1 spectroscopy, phosphorus-31 spectroscopy, and chemical...

21 CFR 892.1000 - Magnetic resonance diagnostic device.

Code of Federal Regulations, 2013 CFR

2013-04-01

... parameters derived from the images and/or spectra may also be produced. The device includes hydrogen-1 (proton) imaging, sodium-23 imaging, hydrogen-1 spectroscopy, phosphorus-31 spectroscopy, and chemical...

21 CFR 892.1000 - Magnetic resonance diagnostic device.

Code of Federal Regulations, 2014 CFR

2014-04-01

... parameters derived from the images and/or spectra may also be produced. The device includes hydrogen-1 (proton) imaging, sodium-23 imaging, hydrogen-1 spectroscopy, phosphorus-31 spectroscopy, and chemical...

NMR Spectroscopy and Its Value: A Primer

ERIC Educational Resources Information Center

Veeraraghavan, Sudha

2008-01-01

Nuclear magnetic resonance (NMR) spectroscopy is widely used by chemists. Furthermore, the use of NMR spectroscopy to solve structures of macromolecules or to examine protein-ligand interactions is popular. Yet, few students entering graduate education in biological sciences have been introduced to this method or its utility. Over the last six…

Topics in Chemical Instrumentation. The Fourier Transform in Chemistry-NMR: Part 4. Two-Dimensional Methods.

ERIC Educational Resources Information Center

Williams, Kathryn R.; King, Roy W.

1990-01-01

Examined are some of the types of two-dimensional spectra. Their application to nuclear magnetic resonance for the elucidation of molecular structure is discussed. Included are J spectroscopy, H-H correlation spectroscopy, heteronuclear correlation spectroscopy, carbon-carbon correlation, nuclear Overhauser effect correlation, experimental…

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.

Properties of the ion-ion hybrid resonator in fusion plasmas

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

Morales, George J.

2015-10-06

The project developed theoretical and numerical descriptions of the properties of ion-ion hybrid Alfvén resonators that are expected to arise in the operation of a fusion reactor. The methodology and theoretical concepts were successfully compared to observations made in basic experiments in the LAPD device at UCLA. An assessment was made of the excitation of resonator modes by energetic alpha particles for burning plasma conditions expected in the ITER device. The broader impacts included the generation of basic insight useful to magnetic fusion and space science researchers, defining new avenues for exploration in basic laboratory experiments, establishing broader contacts betweenmore » experimentalists and theoreticians, completion of a Ph.D. dissertation, and promotion of interest in science through community outreach events and classroom instruction.« less

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 paramagnetic species with a density of approximately 5 × 10{sup 11} spins/cm{sup 2}, which is comparable to the limit obtained for the presently available UHV-EPR spectrometer operating at 10 GHz (X-band). Investigation of electron trapped centers in MgO(001) films shows that the increased resolution offered by the experiments at W-band allows to identify new paramagnetic species, that cannot be differentiated with the currently available methodology.« less

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 antipsychotic medication. The Glx elevations agree with prior magnetic resonance spectroscopy literature, but GABA elevations were unexpected and suggest possible involvement of classes of interneurons not found to show impairments in postmortem studies.

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.

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.

Rubber.

ERIC Educational Resources Information Center

Krishen, Anoop

1989-01-01

This review covers methods for identification, characterization, and determination of rubber and materials in rubber. Topics include: general information, nuclear magnetic resonance spectroscopy, infrared spectroscopy, thermal methods, gel permeation chromatography, size exclusion chromatography, analysis related to safety and health, and…

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 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.

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

NMR clinical imaging and spectroscopy: Its impact on nuclear medicine

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

Not Available

1990-02-02

This is a collection of four papers describing aspects of past and future use of nuclear magnetic resonance as a clinical diagnostic tool. The four papers are entitled (1) What Does NMR Offer that Nuclear Medicine Does Not by Jerry W. Froelich, (2) Oncological Imaging: Now, Future and Impact Jerry W. Froelich, (3) Magnetic Resonance Spectroscopy/Spectroscopic Imaging and Nuclear Medicine: Past, Present and Future by H. Cecil Charles, and (4) MR Cardiology: Now, Future and Impact by Robert J. Herfkens.

NMR clinical imaging and spectroscopy: Its impact on nuclear medicine

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

Not Available

1990-02-02

This is a collection of four papers describing aspects of past and future use of nuclear magnetic resonance as a clinical diagnostic tool. The four papers are entitled (1) What Does NMR Offer that Nuclear Medicine Does Not? by Jerry W. Froelich, (2) Oncological Imaging: Now, Future and Impact Jerry W. Froelich, (3) Magnetic Resonance Spectroscopy/Spectroscopic Imaging and Nuclear Medicine: Past, Present and Future by H. Cecil Charles, and (4) MR Cardiology: Now, Future and Impact by Robert J. Herfkens.

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.

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

The Multiple Resonance Probe: A Novel Device for Industry Compatible Plasma Diagnostics

NASA Astrophysics Data System (ADS)

Brinkmann, Ralf Peter; Storch, Robert; Lapke, Martin; Oberrath, Jens; Schulz, Christian; Styrnoll, Tim; Zietz, Christian; Awakowicz, Peter; Musch, Thomas; Mussenbrock, Thomas; Rolfes, Ilona

2012-10-01

To be useful for the supervision or control of technical plasmas, a diagnostic method must be i) robust and stable, ii) insensitive to perturbation by the process, iii) itself not perturbing the process, iv) clearly and easily interpretable without the need for calibration, v) compliant with the requirements of process integration, and, last but not least, vi) economical in terms of investment, footprint, and maintenance. Plasma resonance spectroscopy, exploiting the natural ability of plasmas to resonate on or near the electron plasma frequency, provides a good basis for such an ``industry compatible'' plasma diagnostics. The contribution will describe the general idea of active plasma resonance spectroscopy and introduce a mathematical formalism for its analysis. It will then focus on the novel multipole resonance probe (MRP), where the excited resonances can be classified explicitly and the connection between the probe response and the desired electron density can be cast as a simple formula. The current state of the MRP project will be described, including the experimental characterization of a prototype in comparison with Langmuir probes, and the development of a specialized measurement circuit.

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

Laskin, Julia

In this work, resonant ejection coupled with surface-induced dissociation (SID) in a Fourier transform ion cyclotron resonance mass spectrometer is used to examine fragmentation kinetics of two singly protonated hexapeptides, RYGGFL and KYGGFL, containing the basic arginine residue and less basic lysine residue at the N-terminus. The kinetics of individual reaction channels at different collision energies are probed by applying a short ejection pulse (1 ms) in resonance with the cyclotron frequency of a selected fragment ion and varying the delay time between ion-surface collision and resonant ejection while keeping total reaction delay time constant. Rice-Ramsperger-Kassel-Marcus (RRKM) modeling of themore » experimental data provides accurate threshold energies and activation entropies of individual reaction channels. Substitution of arginine with less basic lysine has a pronounced effect on the observed fragmentation kinetics of several pathways, including the b2 ion formation, but has little or no effect on formation of the b5+H2O fragment ion. The combination of resonant ejection SID, time- and collision energy-resolved SID, and RRKM modeling of both types of experimental data provides a detailed mechanistic understanding of the primary dissociation pathways of complex gaseous ions.« less

Organosilicon compounds meet subatomic physics: Muon spin resonance.

PubMed

West, Robert; Percival, Paul W

2010-10-21

Silylenes, germylenes and silenes react with muonium atoms, produced from muons generated at a particle accelerator. The resulting radicals can be studied by muon spin resonance spectroscopy, providing unique information about their structure and reactivity.

Polarization spectroscopy of positive and negative trions in an InAs quantum dot

NASA Astrophysics Data System (ADS)

Ware, Morgan E.; Bracker, Allan S.; Stinaff, Eric; Gammon, Daniel; Gershoni, David; Korenev, Vladimir L.

2005-02-01

Using polarization-sensitive photoluminescence and photoluminescence excitation spectroscopy, we study single InAs/GaAs self-assembled quantum dots. The dots were embedded in an n-type, Schottky diode structure allowing for control of the charge state. We present here the exciton, singly charged exciton (positive and negative trions), and the twice negatively charged exciton. For non-resonant excitation below the wetting layer, we observed a large degree of polarization memory from the radiative recombination of both the positive and negative trions. In excitation spectra, through the p-shell, we have found several sharp resonances in the emission from the s-shell recombination of the dot in all charged states. Some of these excitation resonances exhibit strong coulomb shifts upon addition of charges into the quantum dot. One particular resonance of the negatively charged trion was found to exhibit a fine structure doublet under circular polarization. This observation is explained in terms of resonant absorption into the triplet states of the negative trion.

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.

Optical properties of single infrared resonant circular microcavities for surface phonon polaritons.

PubMed

Wang, Tao; Li, Peining; Hauer, Benedikt; Chigrin, Dmitry N; Taubner, Thomas

2013-11-13

Plasmonic antennas are crucial components for nano-optics and have been extensively used to enhance sensing, spectroscopy, light emission, photodetection, and others. Recently, there is a trend to search for new plasmonic materials with low intrinsic loss at new plasmon frequencies. As an alternative to metals, polar crystals have a negative real part of permittivity in the Reststrahlen band and support surface phonon polaritons (SPhPs) with weak damping. Here, we experimentally demonstrate the resonance of single circular microcavities in a thin gold film deposited on a silicon carbide (SiC) substrate in the mid-infrared range. Specifically, the negative permittivity of SiC leads to a well-defined, size-tunable SPhP resonance with a Q factor of around 60 which is much higher than those in surface plasmon polariton (SPP) resonators with similar structures. These infrared resonant microcavities provide new possibilities for widespread applications such as enhanced spectroscopy, sensing, coherent thermal emission, and infrared photodetectors among others throughout the infrared frequency range.

Lights, Camera, Spectroscope! The Basics of Spectroscopy Disclosed Using a Computer Screen

ERIC Educational Resources Information Center

Garrido-Gonza´lez, Jose´ J.; Trillo-Alcala´, María; Sa´nchez-Arroyo, Antonio J.

2018-01-01

The generation of secondary colors in digital devices by means of the additive red, green, and blue color model (RGB) can be a valuable way to introduce students to the basics of spectroscopy. This work has been focused on the spectral separation of secondary colors of light emitted by a computer screen into red, green, and blue bands, and how the…

1 H MR spectroscopy in cervical carcinoma using external phase array body coil at 3.0 Tesla: Prediction of poor prognostic human papillomavirus genotypes.

PubMed

Lin, Gigin; Lai, Chyong-Huey; Tsai, Shang-Yueh; Lin, Yu-Chun; Huang, Yu-Ting; Wu, Ren-Chin; Yang, Lan-Yan; Lu, Hsin-Ying; Chao, Angel; Wang, Chiun-Chieh; Ng, Koon-Kwan; Ng, Shu-Hang; Chou, Hung-Hsueh; Yen, Tzu-Chen; Hung, Ji-Hong

2017-03-01

To assess the clinical value of proton ( 1 H) MR spectroscopy in cervical carcinomas, in the prediction of poor prognostic human papillomavirus (HPV) genotypes as well as persistent disease following concurrent chemoradiotherapy (CCRT). 1 H MR spectroscopy using external phase array coil was performed in 52 consecutive cervical cancer patients at 3 Tesla (T). Poor prognostic HPV genotypes (alpha-7 species or absence of HPV infection) and persistent cervical carcinoma after CCRT were recorded. Statistical significance was calculated with the Mann-Whitney two-sided nonparametric test and areas under the receiver operating characteristics curve (AUC) analysis. A 4.3-fold (P = 0.032) increased level of methyl resonance at 0.9 ppm was found in the poor prognostic HPV genotypes, mainly attributed to the presence of HPV18, with a sensitivity of 75%, a specificity of 81%, and an AUC of 0.76. Poor prognostic HPV genotypes were more frequently observed in patients with adeno-/adenosquamous carcinoma (Chi-square, P < 0.0001). In prediction of the four patients with persistent disease after CCRT, elevated methyl resonance demonstrated a sensitivity of 100%, a specificity of 74%, and an AUC of 0.82. 1 H MR spectroscopy at 3T can be used to depict the elevated lipid resonance levels in cervical carcinomas, as well as help to predict the poor prognostic HPV genotypes and persistent disease following CCRT. Further large studies with longer follow up times are warranted to validate our initial findings. 1 J. Magn. Reson. Imaging 2017;45:899-907. © 2016 International Society for Magnetic Resonance in Medicine.

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.

Application of Computer-Assisted Learning Methods in the Teaching of Chemical Spectroscopy.

ERIC Educational Resources Information Center

Ayscough, P. B.; And Others

1979-01-01

Discusses the application of computer-assisted learning methods to the interpretation of infrared, nuclear magnetic resonance, and mass spectra; and outlines extensions into the area of integrated spectroscopy. (Author/CMV)

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.

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.

Growing up Radical: Investigation of Benzyl-Like Radicals with Increasing Chain Lengths

NASA Astrophysics Data System (ADS)

Korn, Joseph A.; Jawad, Khadija M.; Hewett, Daniel M.; Zwier, Timothy S.

2015-06-01

Combustion processes involve complex chemistry including pathways leading to polyaromatic hydrocarbons (PAHs) from small molecule precursors. Resonance stabilized radicals (RSRs) likely play an important role in the pathways to PAHs due to their unusual stability. Benzyl radical is a prototypical RSR that is stabilized by conjugation with the phenyl ring. Earlier work on α-methyl benzyl radical showed perturbations to the spectroscopy due to a hindered methyl rotor. If the alkyl chain is lengthened then multiple conformations become possible. This talk will discuss the jet-cooled spectroscopy of α-ethyl benzyl radical and α-propyl benzyl radical produced from the discharge of 1-phenyl propanol and 1-phenyl butanol respectively. Electronic spectra were obtained via resonant two-photon ionization, and IR spectra were obtained by resonant ion-dip infrared spectroscopy. Kidwell, N. M.; Reilly, N. J.; Nebgen, B.; Mehta-Hurt, D. N.; Hoehn, R. D.; Kokkin, D. L.; McCarthy, M. C.; Slipchenko, L. V.; Zwier, T. S. The Journal of Physical Chemistry A 2013, 117, 13465.

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.

Spectral methods for study of the G-protein-coupled receptor rhodopsin: I. Vibrational and electronic spectroscopy

NASA Astrophysics Data System (ADS)

Struts, A. V.; Barmasov, A. V.; Brown, M. F.

2015-05-01

Here we review the application of modern spectral methods for the study of G-protein-coupled receptors (GPCRs) using rhodopsin as a prototype. Because X-ray analysis gives us immobile snapshots of protein conformations, it is imperative to apply spectroscopic methods for elucidating their function: vibrational (Raman, FTIR), electronic (UV-visible absorption, fluorescence) spectroscopies, and magnetic resonance (electron paramagnetic resonance, EPR), and nuclear magnetic resonance (NMR). In the first of the two companion articles, we discuss the application of optical spectroscopy for studying rhodopsin in a membrane environment. Information is obtained regarding the time-ordered sequence of events in rhodopsin activation. Isomerization of the chromophore and deprotonation of the retinal Schiff base leads to a structural change of the protein involving the motion of helices H5 and H6 in a pH-dependent process. Information is obtained that is unavailable from X-ray crystallography, which can be combined with spectroscopic studies to achieve a more complete understanding of GPCR function.

Thermal infrared near-field spectroscopy.

PubMed

Jones, Andrew C; Raschke, Markus B

2012-03-14

Despite the seminal contributions of Kirchhoff and Planck describing far-field thermal emission, fundamentally distinct spectral characteristics of the electromagnetic thermal near-field have been predicted. However, due to their evanescent nature their direct experimental characterization has remained elusive. Combining scattering scanning near-field optical microscopy with Fourier-transform spectroscopy using a heated atomic force microscope tip as both a local thermal source and scattering probe, we spectroscopically characterize the thermal near-field in the mid-infrared. We observe the spectrally distinct and orders of magnitude enhanced resonant spectral near-field energy density associated with vibrational, phonon, and phonon-polariton modes. We describe this behavior and the associated distinct on- and off-resonance nanoscale field localization with model calculations of the near-field electromagnetic local density of states. Our results provide a basis for intrinsic and extrinsic resonant manipulation of optical forces, control of nanoscale radiative heat transfer with optical antennas, and use of this new technique of thermal infrared near-field spectroscopy for broadband chemical nanospectroscopy. © 2012 American Chemical Society

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.

Kinetic Description of the Impedance Probe

NASA Astrophysics Data System (ADS)

Oberrath, Jens; Lapke, Martin; Mussenbrock, Thomas; Brinkmann, Ralf

2011-10-01

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 which is the impedance probe (IP). The application of such a probe in plasmas with pressures of 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 spectroscopy was presented by R.P. Brinkmann and can be used to describe the multipole resonance probe (MRP). In principle the IP is interpretable as a special case of the MRP in lower order. Thus, we are able to describe the IP by the kinetic model of the MRP. Based on this model we derive a solution to investigate the influence of kinetic effects to the resonance behavior of the IP. 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 which is the impedance probe (IP). The application of such a probe in plasmas with pressures of 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 spectroscopy was presented by R.P. Brinkmann and can be used to describe the multipole resonance probe (MRP). In principle the IP is interpretable as a special case of the MRP in lower order. Thus, we are able to describe the IP by the kinetic model of the MRP. Based on this model we derive a solution to investigate the influence of kinetic effects to the resonance behavior of the IP. The authors acknowledge the support by the Deutsche Forschungsgemeinschaft (DFG) via the Ruhr University Research School and the Federal Ministry of Education and Research in frame of the PluTO project.

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.

Some features associated with organosilane groups grafted by the sol-gel process onto synthetic talc-like phyllosilicate.

PubMed

Sales, José A A; Petrucelli, Giovanni C; Oliveira, Fernando J V E; Airoldi, Claudio

2006-05-01

Two new lamellar inorganic-organic magnesium silicates have been successfully synthesized by using sol-gel based processes under mild temperature conditions. The talc-organosilicates derived using two silylating agents as the silicon source, (i) 3-chloropropyltrimethoxysilane, and (ii) from the attachment of 5-amino-1,3,4-thiadiazole-2-thiol molecule to this precursor agent, yielded PhMg-Cl and PhMg-Tz phyllosilicates. These organoclays were characterized through elemental analyses, infrared spectroscopy, X-ray diffractometry, surface area, thermogravimetry, and carbon and silicon solid state nuclear magnetic resonance spectroscopy. The results confirmed the presence of organic moieties covalently bonded to the inorganic silicon sheet network of the 2:1 class of phyllosilicates, with a density of organic molecules of 6.6+/-0.1 and 2.7+/-0.2 mmol g(-1) anchored on the inorganic layer and with interlayer distances of 1158 and 1628 pm, respectively. The nuclear magnetic resonances results in the solid state are in agreement with the sequence of carbons distributed in the pendant chains of the original silylating agents and the silicon bonded to oxygen atoms or carbon atoms of the inorganic sheets, as expected for the organically functionalized phyllosilicates. The enhanced potential of the new compound PhMg-Tz as a multi property material was explored in adsorbing cations from aqueous solution. The basic sulfur and nitrogen centers attached to the pendant chains inside the lamellar cavity can coordinate mercury, by presenting an isotherm saturated at 0.19 mmol g(-1) of this heavy metal. The functionality of this organoclay-like material expresses its potential for heavy cation removal from an ecosystem.

Exploring the structure of fucosylated chondroitin sulfate through bottom-up nuclear magnetic resonance and electrospray ionization-high-resolution mass spectrometry approaches.

PubMed

Santos, Gustavo Rc; Porto, Ana Co; Soares, Paulo Ag; Vilanova, Eduardo; Mourão, Paulo As

2017-07-01

Fucosylated chondroitin sulfate (FCS) from sea cucumbers is composed of a chondroitin sulfate (CS) central core and branches of sulfated fucose. The structure of this complex glycosaminoglycan is usually investigated via nuclear magnetic resonance (NMR) analyses of the intact molecule, ergo through a top-down approach, which often yield spectra with intricate sets of signals. Here we employed a bottom-up approach to analyze the FCSs from the sea cucumbers Isostichopus badionotus and Ludwigothurea grisea from their basic constituents, viz. CS cores and sulfated fucose branches, obtained via systematic fragmentation through mild acid hydrolysis. Oligosaccharides derived from the central CS core were analyzed via NMR spectroscopy and the disaccharides produced using chondroitin sulfate lyase via SAX-HPLC. The CS cores from the two species were similar, showing only slight differences in the proportions of 4- or 6-monosulfated and 4,6-disulfated β-d-GalNAc. Sulfated fucose units released from the FCSs were analyzed via NMR and ESI-HRMS spectroscopies. The fucose units from each species presented extensive qualitative differences, but quantitative assessments of these units were hindered, mostly because of their extensive desulfation during the hydrolysis. The bottom-up analysis performed here has proved useful to explore the structure of FCS through a sum-of-the-parts approach in a qualitative manner. We further demonstrate that under specific acidification conditions particular fucose branches can be removed preferentially from FCS. Preparation of derivatives enriched with particular fucose branches could be useful for studies on "structure vs. biological function" of FCS. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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.

Astronomy and Cancer Research: X-Rays and Nanotechnology from Black Holes to Cancer Therapy

NASA Astrophysics Data System (ADS)

Pradhan, Anil K.; Nahar, Sultana N.

It seems highly unlikely that any connection is to be found between astronomy and medicine. But then it also appears to be obvious: X-rays. However, that is quite superficial because the nature of X-rays in the two disciplines is quite different. Nevertheless, we describe recent research on exactly that kind of link. Furthermore, the linkage lies in atomic physics, and via spectroscopy which is a vital tool in astronomy and may also be equally valuable in biomedical research. This review begins with the physics of black hole environments as viewed through X-ray spectroscopy. It is then shown that similar physics can be applied to spectroscopic imaging and therapeutics using heavy-element (high-Z) moieties designed to target cancerous tumors. X-ray irradiation of high-Z nanomaterials as radiosensitizing agents should be extremely efficient for therapy and diagnostics (theranostics). However, broadband radiation from conventional X-ray sources (such as CT scanners) results in vast and unnecessary radiation exposure. Monochromatic X-ray sources are expected to be considerably more efficient. We have developed a new and comprehensive methodology—Resonant Nano-Plasma Theranostics (RNPT)—that encompasses the use of monochromatic X-ray sources and high-Z nanoparticles. Ongoing research entails theoretical computations, numerical simulations, and in vitro and in vivo biomedical experiments. Stemming from basic theoretical studies of Kα resonant photoabsorption and fluorescence in all elements of the Periodic Table, we have established a comprehensive multi-disciplinary program involving researchers from physics, chemistry, astronomy, pathology, radiation oncology and radiology. Large-scale calculations necessary for theory and modeling are done at a variety of computational platforms at the Ohio Supercomputer Center. The final goal is the implementation of RNPT for clinical applications.

UV-Vis spectroscopy of tyrosine side-groups in studies of protein structure. Part 1: basic principles and properties of tyrosine chromophore.

PubMed

Antosiewicz, Jan M; Shugar, David

Spectroscopic properties of tyrosine residues may be employed in structural studies of proteins. Here we discuss several different types of UV-Vis spectroscopy, like normal, difference and second-derivative UV absorption spectroscopy, fluorescence spectroscopy, linear and circular dichroism spectroscopy, and Raman spectroscopy, and corresponding optical properties of the tyrosine chromophore, phenol, which are used to study protein structure.

UV-Vis spectroscopy of tyrosine side-groups in studies of protein structure. Part 1: basic principles and properties of tyrosine chromophore.

PubMed

Antosiewicz, Jan M; Shugar, David

2016-06-01

Spectroscopic properties of tyrosine residues may be employed in structural studies of proteins. Here we discuss several different types of UV-Vis spectroscopy, like normal, difference and second-derivative UV absorption spectroscopy, fluorescence spectroscopy, linear and circular dichroism spectroscopy, and Raman spectroscopy, and corresponding optical properties of the tyrosine chromophore, phenol, which are used to study protein structure.

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.

Acoustic resonance frequency locked photoacoustic spectrometer

DOEpatents

Pilgrim, Jeffrey S.; Bomse, David S.; Silver, Joel A.

2003-09-09

A photoacoustic spectroscopy method and apparatus for maintaining an acoustic source frequency on a sample cell resonance frequency comprising: providing an acoustic source to the sample cell, the acoustic source having a source frequency; repeatedly and continuously sweeping the source frequency across the resonance frequency at a sweep rate; and employing an odd-harmonic of the source frequency sweep rate to maintain the source frequency sweep centered on the resonance frequency.

Spider Silk: From Protein-Rich Gland Fluids to Diverse Biopolymer Fibers

DTIC Science & Technology

2016-01-06

characterize the protein-rich fluid in the various spider silk producing glands. We have been using a battery of magnetic resonance methods including...solution and solid-state nuclear magnetic resonance (NMR) and micro imaging (MRI) in combination with wide angle and small angle X-ray diffraction...range of magnetic resonance methods. We successfully developed magnetic resonance imaging (MRI) techniques with localized spectroscopy to probe the silk

Advances in magnetic resonance neuroimaging techniques in the evaluation of neonatal encephalopathy.

PubMed

Panigrahy, Ashok; Blüml, Stefan

2007-02-01

Magnetic resonance (MR) imaging has become an essential tool in the evaluation of neonatal encephalopathy. Magnetic resonance-compatible neonatal incubators allow sick neonates to be transported to the MR scanner, and neonatal head coils can improve signal-to-noise ratio, critical for advanced MR imaging techniques. Refinement of conventional imaging techniques include the use of PROPELLER techniques for motion correction. Magnetic resonance spectroscopic imaging and diffusion tensor imaging provide quantitative assessment of both brain development and brain injury in the newborn with respect to metabolite abnormalities and hypoxic-ischemic injury. Knowledge of normal developmental changes in MR spectroscopy metabolite concentration and diffusion tensor metrics is essential to interpret pathological cases. Perfusion MR and functional MR can provide additional physiological information. Both MR spectroscopy and diffusion tensor imaging can provide additional information in the differential of neonatal encephalopathy, including perinatal white matter injury, hypoxic-ischemic brain injury, metabolic disease, infection, and birth injury.

Quartz-Enhanced Photoacoustic Spectroscopy with Right-Angle Prism.

PubMed

Liu, Yongning; Chang, Jun; Lian, Jie; Liu, Zhaojun; Wang, Qiang; Qin, Zengguang

2016-02-06

A right-angle prism was used to enhance the acoustic signal of a quartz-enhanced photoacoustic spectroscopy (QEPAS) system. The incident laser beam was parallelly inverted by the right-angle prism and passed through the gap between two tuning fork prongs again to produce another acoustic excitation. Correspondingly, two pairs of rigid metal tubes were used as acoustic resonators with resonance enhancement factors of 16 and 12, respectively. The QEPAS signal was enhanced by a factor of 22.4 compared with the original signal, which was acquired without resonators or a prism. In addition, the system noise was reduced a little with double resonators due to the Q factor decrease. The signal-to-noise ratio (SNR) was greatly improved. Additionally, a normalized noise equivalent absorption coefficient (NNEA) of 5.8 × 10(-8) W·cm(-1)·Hz(-1/2) was achieved for water vapor detection in the atmosphere.

Second harmonic generation spectroscopy in the Reststrahl band of SiC using an infrared free-electron laser

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

Paarmann, Alexander, E-mail: alexander.paarmann@fhi-berlin.mpg.de; Razdolski, Ilya; Melnikov, Alexey

2015-08-24

The Reststrahl spectral region of silicon carbide has recently attracted much attention owing to its potential for mid-infrared nanophotonic applications based on surface phonon polaritons (SPhPs). Studies of optical phonon resonances responsible for surface polariton formation, however, have so far been limited to linear optics. In this Letter, we report the first nonlinear optical investigation of the Reststrahl region of SiC, employing an infrared free-electron laser to perform second harmonic generation (SHG) spectroscopy. We observe two distinct resonance features in the SHG spectra, one attributed to resonant enhancement of the nonlinear susceptibility χ{sup (2)} and the other due to amore » resonance in the Fresnel transmission. Our work clearly demonstrates high sensitivity of mid-infrared SHG to phonon-driven phenomena and opens a route to studying nonlinear effects in nanophotonic structures based on SPhPs.« less

Study of clusters using negative ion photodetachment spectroscopy

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

Zhao, Yuexing

1995-12-01

The weak van der Waals interaction between an open-shell halogen atom and a closed-shell atom or molecule has been investigated using zero electron kinetic energy (ZEKE) spectroscopy. This technique is also applied to study the low-lying electronic states in GaAs and GaAs -. In addition, the spectroscopy and electron detachment dynamics of several small carbon cluster anions are studied using resonant multiphoton detachment spectroscopy.

Broadband near-field infrared spectroscopy with a high temperature plasma light source.

PubMed

Lahneman, D J; Huffman, T J; Xu, Peng; Wang, S L; Grogan, T; Qazilbash, M M

2017-08-21

Scattering-type scanning near-field optical microscopy (S-SNOM) has enormous potential as a spectroscopy tool in the infrared spectral range where it can probe phonon resonances and carrier dynamics at the nanometer lengths scales. However, its applicability is limited by the lack of practical and affordable table-top light sources emitting intense broadband infrared radiation in the 100 cm -1 to 2,500 cm -1 spectral range. This paper introduces a high temperature plasma light source that is both ultra-broadband and has much more radiant power in the infrared spectral range than conventional, table-top thermal light sources such as the globar. We implement this plasma lamp in our near-field optical spectroscopy set up and demonstrate its capability as a broadband infrared nano-spectroscopy light source by obtaining near-field infrared amplitude and phase spectra of the phonon resonances of SiO 2 and SrTiO 3 .

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.

Excitonic Transitions and Off-resonant Optical Limiting in CdS Quantum Dots Stabilized in a Synthetic Glue Matrix

PubMed Central

2007-01-01

Stable films containing CdS quantum dots of mean size 3.4 nm embedded in a solid host matrix are prepared using a room temperature chemical route of synthesis. CdS/synthetic glue nanocomposites are characterized using high resolution transmission electron microscopy, infrared spectroscopy, differential scanning calorimetry and thermogravimetric analysis. Significant blue shift from the bulk absorption edge is observed in optical absorption as well as photoacoustic spectra indicating strong quantum confinement. The exciton transitions are better resolved in photoacoustic spectroscopy compared to optical absorption spectroscopy. We assign the first four bands observed in photoacoustic spectroscopy to 1se–1sh, 1pe–1ph, 1de–1dhand 2pe–2phtransitions using a non interacting particle model. Nonlinear absorption studies are done using z-scan technique with nanosecond pulses in the off resonant regime. The origin of optical limiting is predominantly two photon absorption mechanism.

Tissue Characterization with Quantitative High-Resolution Magic Angle Spinning Chemical Exchange Saturation Transfer Z-Spectroscopy.

PubMed

Zhou, Iris Yuwen; Fuss, Taylor L; Igarashi, Takahiro; Jiang, Weiping; Zhou, Xin; Cheng, Leo L; Sun, Phillip Zhe

2016-11-01

Chemical exchange saturation transfer (CEST) provides sensitive magnetic resonance (MR) contrast for probing dilute compounds via exchangeable protons, serving as an emerging molecular imaging methodology. CEST Z-spectrum is often acquired by sweeping radiofrequency saturation around bulk water resonance, offset by offset, to detect CEST effects at characteristic chemical shift offsets, which requires prolonged acquisition time. Herein, combining high-resolution magic angle spinning (HRMAS) with concurrent application of gradient and rf saturation to achieve fast Z-spectral acquisition, we demonstrated the feasibility of fast quantitative HRMAS CEST Z-spectroscopy. The concept was validated with phantoms, which showed excellent agreement with results obtained from conventional HRMAS MR spectroscopy (MRS). We further utilized the HRMAS Z-spectroscopy for fast ex vivo quantification of ischemic injury with rodent brain tissues after ischemic stroke. This method allows rapid and quantitative CEST characterization of biological tissues and shows potential for a host of biomedical applications.

Study of the interaction of deoxynivalenol with human serum albumin by spectroscopic technique and molecular modelling.

PubMed

Li, Yuqin; Wang, Hao; Jia, Baoxiu; Liu, Caihong; Liu, Ke; Qi, Yongxiu; Hu, Zhide

2013-01-01

The mechanism of interaction between deoxynivalenol (DON) and human serum albumin (HSA) was studied using spectroscopic methods including fluorescence spectra, UV-VIS, Fourier transform infrared (FT-IR) and circular dichroism (CD). The quenching mechanism was investigated in terms of the association constants, number of binding sites and basic thermodynamic parameters. The distance between the HSA donor and the acceptor DON was 2.80 nm as derived from fluorescence resonance energy transfer. The secondary structure compositions of free HSA and its DON complexes were estimated by the FT-IR spectra. Alteration of the secondary protein structure in the presence of DON was confirmed by UV-VIS and CD spectroscopy. Molecular modelling revealed that a DON-protein complex was stabilised by hydrophobic forces and hydrogen bonding. It was potentially useful for elucidating the toxigenicity of DON when combined with biomolecular function effect, transmembrane transport, toxicological testing and the other experiments.

Measurement of molecular length of self-assembled monolayer probed by localized surface plasmon resonance

NASA Astrophysics Data System (ADS)

Ito, Juri; Kajikawa, Kotaro

2016-02-01

We propose a method to measure the variation of the molecular length of self-assembled monolayers (SAMs) when it is exposed to solutions at different pH conditions. The surface immobilized gold nanospheres (SIGNs) shows strong absorption peak at the wavelengths of 600-800 nm when p-polarized light is illuminated. The peak wavelength depends on the length of the gap distance between the SIGNs and the substrate. The gap is supported by the SAM molecules. According to the analytical calculation based on multiple expansion, the relation between the peak wavelength of the SIGN structures and the gap distance is calculated, to evaluate the molecular length of the SAM through the optical absorption spectroscopy for the SIGN structures. The molecular length of the SIGN structure was measured in air, water, acidic, and basic solutions. It was found that the molecular lengths are longer in acidic solutions.

Local Nitric Oxide Production in Viral and Autoimmune Diseases of the Central Nervous System

NASA Astrophysics Data System (ADS)

Hooper, D. Craig; Tsuyoshi Ohnishi, S.; Kean, Rhonda; Numagami, Yoshihiro; Dietzschold, Bernhard; Koprowski, Hilary

1995-06-01

Because of the short half-life of NO, previous studies implicating NO in central nervous system pathology during infection had to rely on the demonstration of elevated levels of NO synthase mRNA or enzyme expression or NO metabolites such as nitrate and nitrite in the infected brain. To more definitively investigate the potential causative role of NO in lesions of the central nervous system in animals infected with neurotropic viruses or suffering from experimental allergic encephalitis, we have determined directly the levels of NO present in the central nervous system of such animals. Using spin trapping of NO and electron paramagnetic resonance spectroscopy, we confirm here that copious amounts of NO (up to 30-fold more than control) are elaborated in the brains of rats infected with rabies virus or borna disease virus, as well as in the spinal cords of rats that had received myelin basic protein-specific T cells.

Physics and instrumentation for imaging in-vivo drug distribution.

PubMed

Singh, M; Waluch, V

2000-03-15

Several imaging methods are currently available to measure drugs noninvasively. Of these, two techniques are today central to such measurements: nuclear imaging and magnetic resonance imaging/spectroscopy (MRI and MRS). While other methods, such as optical techniques, are rapidly gaining in interest, they have not yet attained the degree of development that makes them effective in measuring drugs in living systems, except in a small number of examples. The following introduction provides some basic elements of the potential and the limitations of both nuclear imaging and MRI/MRS techniques, methods that will be used in the studies described in the articles in this issue. However, and for those desiring to gain a better understanding of both methods, the reader is advised to consult much more extensive reviews and books describing such methods. A suggested list of books and articles on Nuclear Imaging and MRI/MRS is given.

Recent advances in quartz enhanced photoacoustic sensing

NASA Astrophysics Data System (ADS)

Patimisco, Pietro; Sampaolo, Angelo; Dong, Lei; Tittel, Frank K.; Spagnolo, Vincenzo

2018-03-01

This review aims to discuss the latest advancements in quartz-enhanced photoacoustic spectroscopy (QEPAS) based trace-gas sensing. Starting from the QEPAS basic physical principles, the most used QEPAS configurations will be described. This is followed by a detailed theoretical analysis and experimental study regarding the influence of quartz tuning forks (QTFs) geometry on their optoacoustic transducer performance. Furthermore, an overview of the latest developments in QEPAS trace-gas sensor technology employing custom QTFs will be reported. Results obtained by exploiting novel micro-resonator configurations, capable of increasing the QEPAS signal-to-noise ratio by more than two orders of magnitude and the utilization of QTF overtone flexural modes for QEPAS based sensing will be presented. A comparison of the QEPAS performance of different spectrophone configurations is reported based upon signal-to-noise ratio. Finally, a novel QEPAS approach allowing simultaneous dual-gas detection will be described.

Teaching Stable Two-Mirror Resonators through the Fractional Fourier Transform

ERIC Educational Resources Information Center

Moreno, Ignacio; Garcia-Martinez, Pascuala; Ferreira, Carlos

2010-01-01

We analyse two-mirror resonators in terms of their fractional Fourier transform (FRFT) properties. We use the basic ABCD ray transfer matrix method to show how the resonator can be regarded as the cascade of two propagation-lens-propagation FRFT systems. Then, we present a connection between the geometric properties of the resonator (the g…

Functional Magnetic Resonance Imaging and Spectroscopic Imaging of the Brain: Application of fMRI and fMRS to Reading Disabilities and Education.

ERIC Educational Resources Information Center

Richards, Todd L.

2001-01-01

This tutorial/review covers functional brain-imaging methods and results used to study language and reading disabilities. Although the emphasis is on magnetic resonance imaging and functional magnetic resonance spectroscopy, other imaging techniques are also discussed including positron emission tomography, electroencephalography,…

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.

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.

Utility of magnetic resonance imaging and nuclear magnetic resonance-based metabolomics for quantification of inflammatory lung injury

PubMed Central

Serkova, Natalie J.; Van Rheen, Zachary; Tobias, Meghan; Pitzer, Joshua E.; Wilkinson, J. Erby; Stringer, Kathleen A.

2008-01-01

Magnetic resonance imaging (MRI) and metabolic nuclear magnetic resonance (NMR) spectroscopy are clinically available but have had little application in the quantification of experimental lung injury. There is a growing and unfulfilled need for predictive animal models that can improve our understanding of disease pathogenesis and therapeutic intervention. Integration of MRI and NMR could extend the application of experimental data into the clinical setting. This study investigated the ability of MRI and metabolic NMR to detect and quantify inflammation-mediated lung injury. Pulmonary inflammation was induced in male B6C3F1 mice by intratracheal administration of IL-1β and TNF-α under isoflurane anesthesia. Mice underwent MRI at 2, 4, 6, and 24 h after dosing. At 6 and 24 h lungs were harvested for metabolic NMR analysis. Data acquired from IL-1β+TNF-α-treated animals were compared with saline-treated control mice. The hyperintense-to-total lung volume (HTLV) ratio derived from MRI was higher in IL-1β+TNF-α-treated mice compared with control at 2, 4, and 6 h but returned to control levels by 24 h. The ability of MRI to detect pulmonary inflammation was confirmed by the association between HTLV ratio and histological and pathological end points. Principal component analysis of NMR-detectable metabolites also showed a temporal pattern for which energy metabolism-based biomarkers were identified. These data demonstrate that both MRI and metabolic NMR have utility in the detection and quantification of inflammation-mediated lung injury. Integration of these clinically available techniques into experimental models of lung injury could improve the translation of basic science knowledge and information to the clinic. PMID:18441091

Ultrafast Non-thermal Response of Plasmonic Resonance in Gold Nanoantennas

NASA Astrophysics Data System (ADS)

Soavi, Giancarlo; Valle, Giuseppe Della; Biagioni, Paolo; Cattoni, Andrea; Longhi, Stefano; Cerullo, Giulio; Brida, Daniele

Ultrafast thermalization of electrons in metal nanostructures is studied by means of pump-probe spectroscopy. We track in real-time the plasmon resonance evolution, providing a tool for understanding and controlling gold nanoantennas non-linear optical response.

Direct monitoring by carbon-13 nuclear magnetic resonance spectroscopy of the metabolism and metabolic rate of 13C-labeled compounds in vivo.

PubMed

Iida, K; Hidoh, O; Fukami, J; Kajiwara, M

1991-01-01

Carbon-13 nuclear magnetic resonance spectroscopy has been used to observe the transformations of [1-13C]-D-glucose to [1,1'-13C2]-D-trehalose, and [3-13C]-L-alanine to [2-13C]-L-glutamic acid in the living body of Gryllodes sigillatus. [3-13C]-D-Alanine was not metabolized. The metabolic rate of [1-13C]-D-glucose was found to be altered by prior injection of boric acid.

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.

Single Bacterium Detection Using Sers

NASA Astrophysics Data System (ADS)

Gonchukov, S. A.; Baikova, T. V.; Alushin, M. V.; Svistunova, T. S.; Minaeva, S. A.; Ionin, A. A.; Kudryashov, S. I.; Saraeva, I. N.; Zayarny, D. A.

2016-02-01

This work is devoted to the study of a single Staphylococcus aureus bacterium detection using surface-enhanced Raman spectroscopy (SERS) and resonant Raman spectroscopy (RS). It was shown that SERS allows increasing sensitivity of predominantly low frequency lines connected with the vibrations of Amide, Proteins and DNA. At the same time the lines of carotenoids inherent to this kind of bacterium are well-detected due to the resonance Raman scattering mechanism. The reproducibility and stability of Raman spectra strongly depend on the characteristics of nanostructured substrate, and molecular structure and size of the tested biological object.

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.

Optical and Magnetic Resonance Investigations of 3d Ions in Single Crystal Hosts: Candidates for Tunable Solid-State Lasers

DTIC Science & Technology

1994-04-25

Resonance Spectroscopy of Chromium-Doped Lanthanum Lutetium Gallium Garnet, M. H. Whitmore and D.J. Singel 8. 51V modulation of Mn5+ electron spin echoes in...Doped Lanthanum Lutetium Gallium Garnet Chapter 9 Characterization of Optical Centers in Mn.Ba3(VO4)2 178 by Spin-Echo EPR Spectroscopy I I ! I ii I i I I...previously unpublished EPR results on Cr:gehlenites (Chapter 6) and Cr:LLGG (lanthanum lutetium gallium garnet) (Chapter 8). The gehlenite spectra do

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.

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

Spectroscopic Sleuthing. An Introduction to Forensic Science.

ERIC Educational Resources Information Center

Zdravkovich, Vera; Cunniff, Patricia A.

1991-01-01

Described is a program in which students learn about spectroscopy and instrumentation to solve a chemical forensic mystery. Infrared and nuclear magnetic resonance (NMR) spectroscopy, refractometry, and chromatographic techniques were used. An example of a mystery case is included. (KR)

Tailoring bifunctional hybrid organic–inorganic nanoadsorbents by the choice of functional layer composition probed by adsorption of Cu2+ ions

PubMed Central

Tomina, Veronika V; Melnyk, Inna V; Zub, Yuriy L; Kareiva, Aivaras; Vaclavikova, Miroslava; Kessler, Vadim G

2017-01-01

Spherical silica particles with bifunctional (≡Si(CH2)3NH2/≡SiCH3, ≡Si(CH2)3NH2/≡Si(CH2)2(CF2)5CF3) surface layers were produced by a one-step approach using a modified Stöber method in three-component alkoxysilane systems, resulting in greatly increased contents of functional components. The content of functional groups and thermal stability of the surface layers were analyzed by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, and 13C and 29Si solid-state NMR spectroscopy revealing their composition and organization. The fine chemical structure of the surface in the produced hybrid adsorbent particles and the ligand distribution were further investigated by electron paramagnetic resonance (EPR) and electron spectroscopy of diffuse reflectance (ESDR) spectroscopy using Cu2+ ion coordination as a probe. The composition and structure of the emerging surface complexes were determined and used to provide an insight into the molecular structure of the surfaces. It was demonstrated that the introduction of short hydrophobic (methyl) groups improves the kinetic characteristics of the samples during the sorption of copper(II) ions and promotes fixation of aminopropyl groups on the surface of silica microspheres. The introduction of long hydrophobic (perfluoroctyl) groups changes the nature of the surface, where they are arranged in alternately hydrophobic/hydrophilic patches. This makes the aminopropyl groups huddled and less active in the sorption of metal cations. The size and aggregation/morphology of obtained particles was optimized controlling the synthesis conditions, such as concentrations of reactants, basicity of the medium, and the process temperature. PMID:28243572

Raman spectroscopy of graphene-based materials and its applications in related devices.

PubMed

Wu, Jiang-Bin; Lin, Miao-Ling; Cong, Xin; Liu, He-Nan; Tan, Ping-Heng

2018-03-05

Graphene-based materials exhibit remarkable electronic, optical, and mechanical properties, which has resulted in both high scientific interest and huge potential for a variety of applications. Furthermore, the family of graphene-based materials is growing because of developments in preparation methods. Raman spectroscopy is a versatile tool to identify and characterize the chemical and physical properties of these materials, both at the laboratory and mass-production scale. This technique is so important that most of the papers published concerning these materials contain at least one Raman spectrum. Thus, here, we systematically review the developments in Raman spectroscopy of graphene-based materials from both fundamental research and practical (i.e., device applications) perspectives. We describe the essential Raman scattering processes of the entire first- and second-order modes in intrinsic graphene. Furthermore, the shear, layer-breathing, G and 2D modes of multilayer graphene with different stacking orders are discussed. Techniques to determine the number of graphene layers, to probe resonance Raman spectra of monolayer and multilayer graphenes and to obtain Raman images of graphene-based materials are also presented. The extensive capabilities of Raman spectroscopy for the investigation of the fundamental properties of graphene under external perturbations are described, which have also been extended to other graphene-based materials, such as graphene quantum dots, carbon dots, graphene oxide, nanoribbons, chemical vapor deposition-grown and SiC epitaxially grown graphene flakes, composites, and graphene-based van der Waals heterostructures. These fundamental properties have been used to probe the states, effects, and mechanisms of graphene materials present in the related heterostructures and devices. We hope that this review will be beneficial in all the aspects of graphene investigations, from basic research to material synthesis and device applications.

Computed tomography, magnetic resonance, and ultrasound imaging: basic principles, glossary of terms, and patient safety.

PubMed

Cogbill, Thomas H; Ziegelbein, Kurt J

2011-02-01

The basic principles underlying computed tomography, magnetic resonance, and ultrasound are reviewed to promote better understanding of the properties and appropriate applications of these 3 common imaging modalities. A glossary of frequently used terms for each technique is appended for convenience. Risks to patient safety including contrast-induced nephropathy, radiation-induced malignancy, and nephrogenic systemic fibrosis are discussed. Copyright © 2011 Elsevier Inc. All rights reserved.

Effects of size, shape, and frequency on the antiferromagnetic resonance linewidth of MnF

NASA Technical Reports Server (NTRS)

Obrien, K. C.

1973-01-01

The research concerning the properties and application of solid state materials at submillimeter frequencies is summarized. Work reported includes: far infrared Fourier spectroscopy; studies of the antiferromagnetic resonance line in MnF2 at millimeter wavelengths; numerical solution of the equations of motion of a general two-sublattice antiferromagnet; study of antiferromagnetic resonance line in NiO powder; and resonance investigations of several indium thisospinels at millimeter wavelengths.

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 triiodide at the moment of photodissociation determines the stretching frequency of diiodide. The functions of heme proteins involve ligand binding and dissociation events, which are facilitated by the fast exchange of energy between the heme and aqueous solvent. It is known that the heme's propionic acid side chains act as an effective "gateway" for this fast energy exchange. In this dissertation it is shown that the propionic chains within myoglobin posses significant structural heterogeneity, suggesting that this may be an important factor in facilitating the functions of heme proteins.

Chemical bonding in aqueous hexacyano cobaltate from photon- and electron-detection perspectives

PubMed Central

Lalithambika, Sreeju Sreekantan Nair; Atak, Kaan; Seidel, Robert; Neubauer, Antje; Brandenburg, Tim; Xiao, Jie; Winter, Bernd; Aziz, Emad F.

2017-01-01

The electronic structure of the [Co(CN)6]3− complex dissolved in water is studied using X-ray spectroscopy techniques. By combining electron and photon detection methods from the solutions ionized or excited by soft X-rays we experimentally identify chemical bonding between the metal center and the CN ligand. Non-resonant photoelectron spectroscopy provides solute electron binding energies, and nitrogen 1 s and cobalt 2p resonant core-level photoelectron spectroscopy identifies overlap between metal and ligand orbitals. By probing resonances we are able to qualitatively determine the ligand versus metal character of the respective occupied and non-occupied orbitals, purely by experiment. For the same excitations we also detect the emitted X-rays, yielding the complementary resonant inelastic X-ray scattering spectra. For a quantitative interpretation of the spectra, we perform theoretical electronic-structure calculations. The latter provide both orbital energies and orbital character which are found to be in good agreement with experimental energies and with experimentally inferred orbital mixing. We also report calculated X-ray absorption spectra, which in conjunction with our orbital-structure analysis, enables us to quantify various bonding interactions with a particular focus on the water-solvent – ligand interaction and the strength of π-backbonding between metal and ligand. PMID:28098216

Resonance-Raman spectro-electrochemistry of intermediates in molecular artificial photosynthesis of bimetallic complexes.

PubMed

Zedler, Linda; Guthmuller, Julien; Rabelo de Moraes, Inês; Kupfer, Stephan; Krieck, Sven; Schmitt, Michael; Popp, Jürgen; Rau, Sven; Dietzek, Benjamin

2014-05-25

The sequential order of photoinduced charge transfer processes and accompanying structure changes were analyzed by UV-vis and resonance-Raman spectroscopy of intermediates of a Ru(ii) based photocatalytic hydrogen evolving system obtained by electrochemical reduction.

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

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

Magnesium Nanoparticle Plasmonics.

PubMed

Biggins, John S; Yazdi, Sadegh; Ringe, Emilie

2018-06-13

Nanoparticles of some metals (Cu/Ag/Au) sustain oscillations of their electron cloud called localized surface plasmon resonances (LSPRs). These resonances can occur at optical frequencies and be driven by light, generating enhanced electric fields and spectacular photon scattering. However, current plasmonic metals are rare, expensive, and have a limited resonant frequency range. Recently, much attention has been focused on earth-abundant Al, but Al nanoparticles cannot resonate in the IR. The earth-abundant Mg nanoparticles reported here surmount this limitation. A colloidal synthesis forms hexagonal nanoplates, reflecting Mg's simple hexagonal lattice. The NPs form a thin self-limiting oxide layer that renders them stable suspended in 2-propanol solution for months and dry in air for at least two week. They sustain LSPRs observable in the far-field by optical scattering spectroscopy. Electron energy loss spectroscopy experiments and simulations reveal multiple size-dependent resonances with energies across the UV, visible, and IR. The symmetry of the modes and their interaction with the underlying substrate are studied using numerical methods. Colloidally synthesized Mg thus offers a route to inexpensive, stable nanoparticles with novel shapes and resonances spanning the entire UV-vis-NIR spectrum, making them a flexible addition to the nanoplasmonics toolbox.

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 studies, our results support the current histopathologically driven hypothesis that such T2-weighted hyperintensities may be related to intramyelinic edema. Copyright © 2015 Elsevier Inc. All rights reserved.

The DTIC Review: Volume 2, Number 4, Surviving Chemical and Biological Warfare

DTIC Science & Technology

1996-12-01

CHROMATOGRAPHIC ANALYSIS, NUCLEAR MAGNETIC RESONANCE, INFRARED SPECTROSCOPY , ARMY RESEARCH, DEGRADATION, VERIFICATION, MASS SPECTROSCOPY , LIQUID... mycotoxins . Such materials are not attractive as weapons of mass destruction however, as large amounts are required to produce lethal effects. In...VERIFICATION, ATOMIC ABSORPTION SPECTROSCOPY , ATOMIC ABSORPTION. AL The DTIC Review Defense Technical Information Center AD-A285 242 AD-A283 754 EDGEWOOO

Interactions between α-amylase and an acidic branched polysaccharide from green tea.

PubMed

Wu, Shuyun; Lai, Minghua; Luo, Jiahao; Pan, Jingwen; Zhang, Li-Ming; Yang, Liqun

2017-01-01

To understand the mechanism responsible for the α-amylase inhibitory activity of tea polysaccharides, the interaction between α-amylase and an acidic branched tea polysaccharide (TPSA) was investigated using fluorescence spectroscopy and resonance light scattering analysis. TPSA, exhibiting inhibitory activity towards α-amylase (the maximum inhibition percentage of 65%), was isolated from green tea (Camellia sinensis) and characterized by nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, and gas chromatography. Synchronous fluorescence spectroscopy revealed that the binding interaction between the tryptophan residues of α-amylase and TPSA was predominant. Based on the fluorescence quenching effect of tryptophan residues induced by TPSA, the binding constants between α-amylase and TPSA were determined to be 18.6×10 6 , 8.0×10 6 and 4.6×10 6 L·mol -1 at 20, 30 and 37°C, respectively. The calculated Gibbs free-energy changes were negative, indicating that the bonding interaction was a spontaneous process. The enthalpy and the entropy changes were -62.13 KJ·mol -1 and -0.0728 KJ·mol -1 ·K -1 , suggesting that hydrogen bonding interactions might play a major role in the binding process. The formation of an α-amylase/TPSA complex was evidenced by fluorescence quenching and resonance light scattering analysis, and this complex could be the main contributor to the α-amylase inhibitory activity of TPSA. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

Impact of the plasmonic near- and far-field resonance-energy shift on the enhancement of infrared vibrational signals.

PubMed

Vogt, Jochen; Huck, Christian; Neubrech, Frank; Toma, Andrea; Gerbert, David; Pucci, Annemarie

2015-09-07

We report on the impact of the differing spectral near- and far-field properties of resonantly excited gold nanoantennas on the vibrational signal enhancement in surface-enhanced infrared absorption (SEIRA). The knowledge on both spectral characteristics is of considerable importance for the optimization of plasmonic nanostructures for surface-enhanced spectroscopy techniques. From infrared micro-spectroscopic measurements, we simultaneously obtain spectral information on the plasmonic far-field response and, via SEIRA spectroscopy of a test molecule, on the near-field enhancement. The molecular test layer of 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP) was deposited on the surface of gold nanoantennas with different lengths and thus different far-field resonance energies. We carefully studied the Fano-type vibrational lines in a broad spectral window, in particular, how the various vibrational signals are enhanced in relation to the ratio of the far-field plasmonic resonance and the molecular vibrational frequencies. As a detailed experimental proof of former simulation studies, we show the clearly red-shifted maximum SEIRA enhancement compared to the far-field resonance.

Towards Single Biomolecule Imaging via Optical Nanoscale Magnetic Resonance Imaging.

PubMed

Boretti, Alberto; Rosa, Lorenzo; Castelletto, Stefania

2015-09-09

Nuclear magnetic resonance (NMR) spectroscopy is a physical marvel in which electromagnetic radiation is charged and discharged by nuclei in a magnetic field. In conventional NMR, the specific nuclei resonance frequency depends on the strength of the magnetic field and the magnetic properties of the isotope of the atoms. NMR is routinely utilized in clinical tests by converting nuclear spectroscopy in magnetic resonance imaging (MRI) and providing 3D, noninvasive biological imaging. While this technique has revolutionized biomedical science, measuring the magnetic resonance spectrum of single biomolecules is still an intangible aspiration, due to MRI resolution being limited to tens of micrometers. MRI and NMR have, however, recently greatly advanced, with many breakthroughs in nano-NMR and nano-MRI spurred by using spin sensors based on an atomic impurities in diamond. These techniques rely on magnetic dipole-dipole interactions rather than inductive detection. Here, novel nano-MRI methods based on nitrogen vacancy centers in diamond are highlighted, that provide a solution to the imaging of single biomolecules with nanoscale resolution in-vivo and in ambient conditions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

70th anniversary of the E K Zavoisky Kazan Physical-Technical Institute, Kazan Scientific Center of the Russian Academy of Sciences (Scientific session of the Physical Sciences Division of the Russian Academy of Sciences, 4 February 2016)

NASA Astrophysics Data System (ADS)

2016-06-01

A scientific session of the Physical Sciences Division of the Russian Academy of Sciences (RAS) was held on 4 February 2016 at the E K Zavoisky Kazan Physical-Technical Institute, Kazan Scientific Center (KSC), RAS, devoted to the 70th anniversary of the E K Zavoisky Kazan Physical-Technical Institute, KSC RAS. The agenda posted on the website of the Physical Sciences Division RAS http://www.gpad.ac.ru comprised the following reports: (1) Demishev S V (Prokhorov General Physics Institute, RAS, Moscow) "Quantum phase transitions in spiral magnets without an inversion center"; (2) Smirnov A I (Kapitza Institute for Physical Problems, RAS, Moscow) "Magnetic resonance of spinons in quantum magnets"; (3) Ryazanov V V (Institute of Solid State Physics, RAS, Chernogolovka, Moscow region) "Coherent and nonequilibrium phenomena in superconductor- and ferromagnet-based structures"; (4) Mel'nikov A S (Institute for Physics of Microstructures, RAS, Nizhny Novgorod) "Mechanisms of long-range proximity effects in superconducting spintronics"; (5) Fel'dman E B (Institute of Problems of Chemical Physics, RAS, Chernogolovka, Moscow region) "Magnus expansion paradoxes in the study of equilibrium magnetization and entanglement in multi-pulse spin locking"; (6) Fraerman A A (Institute for Physics of Microstructures, RAS, Nizhny Novgorod) "Features of the motion of spin-1/2 particles in a noncoplanar magnetic field"; (7) Salikhov K M (E K Zavoisky Kazan Physical-Technical Institute, KSC, RAS, Kazan) "Electron paramagnetic resonance applications: promising developments at the E K Zavoisky Kazan Physical-Technical Institute of the Russian Academy of Sciences"; (8) Vinogradov E A (Institute for Spectroscopy, RAS, Troitsk, Moscow) "Ultrathin film characterization using far-field surface polariton spectroscopy"; (9) Glyavin M Yu (Institute of Applied Physics, RAS, Nizhny Novgorod) "High-power terahertz sources for spectroscopy and material diagnostics"; (10) Soltamov V A (Ioffe Institute, RAS, Saint Petersburg) "Radio spectroscopy of the optically aligned spin states of color centers in silicon carbide"; (11) Kalachev A A (E K Zavoisky Kazan Physical-Technical Institute, KSC, RAS, Kazan) "Long-range quantum communication. Basic devices and prospects for development"; (12) Kuznetsov D (Bruker Corporation, Moscow) "Recent magnetic resonance hardware advances at the Bruker Corporation". Papers based on talks 1, 2, 4-7, 9, and 10 are presented below. • Quantum phase transitions in spiral magnets without an inversion center, S V Demishev, V V Glushkov, S V Grigoriev, M I Gilmanov, I I Lobanova, A N Samarin, A V Semeno, N E Sluchanko Physics-Uspekhi, 2016, Volume 59, Number 6, Pages 559-563 • Magnetic resonance of spinons in quantum magnets, A I Smirnov Physics-Uspekhi, 2016, Volume 59, Number 6, Pages 564-570 • Long-range ballistic transport mechanisms in superconducting spintronics, A V Samokhvalov, A S Mel'nikov, A I Buzdin Physics-Uspekhi, 2016, Volume 59, Number 6, Pages 571-576 • Magnus expansion paradoxes in the study of equilibrium magnetization and entanglement in multi-pulse spin locking, E I Kuznetsova, E B Fel'dman, D E Feldman Physics-Uspekhi, 2016, Volume 59, Number 6, Pages 577-582 • Features of the motion of spin-1/2 particles in a noncoplanar magnetic field, D A Tatarskiy, A V Petrenko, S N Vdovichev, O G Udalov, Yu V Nikitenko, A A Fraerman Physics-Uspekhi, 2016, Volume 59, Number 6, Pages 583-587 • Electron paramagnetic resonance applications: promising developments at the E K Zavoisky Kazan Physical-Technical Institute of the Russian Academy of Sciences, K M Salikhov Physics-Uspekhi, 2016, Volume 59, Number 6, Pages 588-594 • High power terahertz sources for spectroscopy and material diagnostics, M Yu Glyavin, G G Denisov, V E Zapevalov, M A Koshelev, M Yu Tretyakov, A I Tsvetkov Physics-Uspekhi, 2016, Volume 59, Number 6, Pages 595-604 • Radio spectroscopy of the optically aligned spin states of color centers in silicon carbide, V A Soltamov, P G Baranov Physics-Uspekhi, 2016, Volume 59, Number 6, Pages 605-610

The requirement of ammonium or other cations linked with p-cresol sulfate for cross-reactivity with a peptide of myelin basic protein.

PubMed

Jackson, Patricia L; Cao, Ligong; Blalock, J Edwin; Whitaker, John N

2003-10-15

Urinary myelin basic protein-like material (MBPLM), so designated because of its immunoreactivity with a polyclonal antibody directed against a cryptic epitope located in residues 83-89 of myelin basic protein (MBP), exists in humans normally but increases in concentration in patients with multiple sclerosis who have progressive disease. Given its possible role in reflecting events of neural tissue destruction occurring in multiple sclerosis, urinary MBPLM is a candidate surrogate marker for this phase of the disease. Previously, it has been demonstrated that p-cresol sulfate (PCS) is the dominant component of MBPLM; however, another component(s) was essential in enabling p-cresol sulfate to have molecular mimicry with MBP peptide 83-89 detected by immunoreactivity. In the present investigation, this remaining component(s) was characterized by a combination of high performance size exclusion chromatography followed by nuclear magnetic resonance spectroscopy and shown to be ammonium. The monovalent cation ammonium could be substituted in vitro by several different monovalent and divalent cations, most notably zinc, in restoring to deprotonated p-cresol sulfate its immunoreactivity as MBPLM. These findings indicate the basis for the unexpected molecular mimicry between an epitope of an encephalitogenic protein and a complex containing a small organic molecule, p-cresol sulfate. Furthermore, the reaction of either ammonium or other cations with p-cresol sulfate may represent an in vivo process directly related to damage of axonal membranes.

Spin-wave interference in microscopic permalloy tubes

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

Balhorn, Felix; Nagrodzki, Lukas; Mendach, Stefan

2013-06-03

We present permalloy coated needles which act as spin-wave resonators. The permalloy coated needles were investigated using microwave absorption spectroscopy. Thereby, we found up to three resonant modes which correspond to constructively interfering azimuthal spin waves. The resonant modes are well reproduced in calculations based on an analytical model for the spin-wave dispersion employing periodic boundary conditions. The dependence of the resonance frequencies on the needles' radii and the external magnetic field is demonstrated experimentally.

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.

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.

Laser heating of scanning probe tips for thermal near-field spectroscopy and imaging

NASA Astrophysics Data System (ADS)

O'Callahan, Brian T.; Raschke, Markus B.

2017-02-01

Spectroscopy and microscopy of the thermal near-field yield valuable insight into the mechanisms of resonant near-field heat transfer and Casimir and Casimir-Polder forces, as well as providing nanoscale spatial resolution for infrared vibrational spectroscopy. A heated scanning probe tip brought close to a sample surface can excite and probe the thermal near-field. Typically, tip temperature control is provided by resistive heating of the tip cantilever. However, this requires specialized tips with limited temperature range and temporal response. By focusing laser radiation onto AFM cantilevers, we achieve heating up to ˜1800 K, with millisecond thermal response time. We demonstrate application to thermal infrared near-field spectroscopy (TINS) by acquiring near-field spectra of the vibrational resonances of silicon carbide, hexagonal boron nitride, and polytetrafluoroethylene. We discuss the thermal response as a function of the incident excitation laser power and model the dominant cooling contributions. Our results provide a basis for laser heating as a viable approach for TINS, nanoscale thermal transport measurements, and thermal desorption nano-spectroscopy.

High-Throughput Screening by Nuclear Magnetic Resonance (HTS by NMR) for the Identification of PPIs Antagonists.

PubMed

Wu, Bainan; Barile, Elisa; De, Surya K; Wei, Jun; Purves, Angela; Pellecchia, Maurizio

2015-01-01

In recent years the ever so complex field of drug discovery has embraced novel design strategies based on biophysical fragment screening (fragment-based drug design; FBDD) using nuclear magnetic resonance spectroscopy (NMR) and/or structure-guided approaches, most often using X-ray crystallography and computer modeling. Experience from recent years unveiled that these methods are more effective and less prone to artifacts compared to biochemical high-throughput screening (HTS) of large collection of compounds in designing protein inhibitors. Hence these strategies are increasingly becoming the most utilized in the modern pharmaceutical industry. Nonetheless, there is still an impending need to develop innovative and effective strategies to tackle other more challenging targets such as those involving protein-protein interactions (PPIs). While HTS strategies notoriously fail to identify viable hits against such targets, few successful examples of PPIs antagonists derived by FBDD strategies exist. Recently, we reported on a new strategy that combines some of the basic principles of fragment-based screening with combinatorial chemistry and NMR-based screening. The approach, termed HTS by NMR, combines the advantages of combinatorial chemistry and NMR-based screening to rapidly and unambiguously identify bona fide inhibitors of PPIs. This review will reiterate the critical aspects of the approach with examples of possible applications.

High-throughput screening by Nuclear Magnetic Resonance (HTS by NMR) for the identification of PPIs antagonists

PubMed Central

Wu, Bainan; Barile, Elisa; De, Surya K.; Wei, Jun; Purves, Angela; Pellecchia, Maurizio

2015-01-01

In recent years the ever so complex field of drug discovery has embraced novel design strategies based on biophysical fragment screening (fragment-based drug design; FBDD) using nuclear magnetic resonance spectroscopy (NMR) and/or structure-guided approaches, most often using X-ray crystallography and computer modeling. Experience from recent years unveiled that these methods are more effective and less prone to artifacts compared to biochemical high-throughput screening (HTS) of large collection of compounds in designing protein inhibitors. Hence these strategies are increasingly becoming the most utilized in the modern pharmaceutical industry. Nonetheless, there is still an impending need to develop innovative and effective strategies to tackle other more challenging targets such as those involving protein-protein interactions (PPIs). While HTS strategies notoriously fail to identify viable hits against such targets, few successful examples of PPIs antagonists derived by FBDD strategies exist. Recently, we reported on a new strategy that combines some of the basic principles of fragment-based screening with combinatorial chemistry and NMR-based screening. The approach, termed HTS by NMR, combines the advantages of combinatorial chemistry and NMR-based screening to rapidly and unambiguously identify bona fide inhibitors of PPIs. This review will reiterate the critical aspects of the approach with examples of possible applications. PMID:25986689

Introduction of the Floquet-Magnus expansion in solid-state nuclear magnetic resonance spectroscopy.

PubMed

Mananga, Eugène S; Charpentier, Thibault

2011-07-28

In this article, we present an alternative expansion scheme called Floquet-Magnus expansion (FME) used to solve a time-dependent linear differential equation which is a central problem in quantum physics in general and solid-state nuclear magnetic resonance (NMR) in particular. The commonly used methods to treat theoretical problems in solid-state NMR are the average Hamiltonian theory (AHT) and the Floquet theory (FT), which have been successful for designing sophisticated pulse sequences and understanding of different experiments. To the best of our knowledge, this is the first report of the FME scheme in the context of solid state NMR and we compare this approach with other series expansions. We present a modified FME scheme highlighting the importance of the (time-periodic) boundary conditions. This modified scheme greatly simplifies the calculation of higher order terms and shown to be equivalent to the Floquet theory (single or multimode time-dependence) but allows one to derive the effective Hamiltonian in the Hilbert space. Basic applications of the FME scheme are described and compared to previous treatments based on AHT, FT, and static perturbation theory. We discuss also the convergence aspects of the three schemes (AHT, FT, and FME) and present the relevant references. © 2011 American Institute of Physics

Direct Observation of Electron-Phonon Coupling and Slow Vibrational Relaxation in Organic-Inorganic Hybrid Perovskites

NASA Astrophysics Data System (ADS)

Hurtado Parra, Sebastian; Straus, Daniel; Iotov, Natasha; Fichera, Bryan; Gebhardt, Julian; Rappe, Andrew; Subotnik, Joseph; Kikkawa, James; Kagan, Cherie

Quantum and dielectric confinement effects in Ruddlesden-Popper 2D hybrid perovskites create excitons with a binding energy exceeding 150 meV. We exploit the large exciton binding energy to study exciton and carrier dynamics as well as electron-phonon coupling (EPC) in hybrid perovskites using absorption and photoluminescence (PL) spectroscopies. At temperatures <75 K, we resolve splitting of the excitonic absorption and PL into multiple regularly spaced resonances every 40-46 meV, consistent with EPC to phonons located on the organic cation. We also resolve resonances with a 14 meV spacing, in accord with coupling to phonons with mixed organic and inorganic character. These assignments are supported by density-functional theory calculations. Hot exciton PL and time-resolved PL measurements show that vibrational relaxation occurs on a picosecond time scale competitive with that for PL. At temperatures >75 K, excitonic absorption and PL exhibit homogeneous broadening. While absorption remains homogeneous, PL becomes inhomogeneous at temperatures <75K, which we speculate is caused by the formation and subsequent dynamics of a polaronic exciton. This work is supported by the U.S. Department of Energy, Office of Basic Energy Sciences Grant DE-SC0002158 and the National Science Foundation Graduate Research Fellowship Grant DGE-1321851.

Metabolic and hemodynamic events following changes in neuronal activity: current hypotheses, theoretical predictions and in vivo NMR experimental findings

PubMed Central

Mangia, Silvia; Giove, Federico; Tkáč, Ivan; Logothetis, Nikos K.; Henry, Pierre-Gilles; Olman, Cheryl A.; Maraviglia, Bruno; Di Salle, Francesco; Uğurbil, Kâmil

2009-01-01

Unraveling the energy metabolism and the hemodynamic outcomes of excitatory and inhibitory neuronal activity is critical not only for our basic understanding of overall brain function, but also for the understanding of many brain disorders. Methodologies of magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) are powerful tools for the non-invasive investigation of brain metabolism and physiology. However, the temporal and spatial resolution of in vivo MRS and MRI is not suitable to provide direct evidence for hypotheses that involve metabolic compartmentalization between different cell types, or to untangle the complex neuronal micro-circuitry which results in changes of electrical activity. This review aims at describing how the current models of brain metabolism, mainly built on the basis of in vitro evidence, relate to experimental findings recently obtained in vivo by 1H MRS, 13C MRS and MRI. The hypotheses related to the role of different metabolic substrates, the metabolic neuron-glia interactions, along with the available theoretical predictions of the energy budget of neurotransmission, will be discussed. In addition, the cellular and network mechanisms that characterize different types of increased and suppressed neuronal activity will be considered within the sensitivity-constraints of MRS and MRI. PMID:19002199

Spectroscopic and Computational Studies of (µ-Oxo)(µ-1,2-peroxo)diiron(III) Complexes of Relevance to Nonheme Diiron Oxygenase Intermediates

PubMed Central

Fiedler, Adam T.; Shan, Xiaopeng; Mehn, Mark P.; Kaizer, József; Torelli, Stéphane; Frisch, Jonathan R.; Kodera, Masahito; Que, Lawrence

2009-01-01

With the goal of gaining insight into the structures of peroxo intermediates observed for oxygen activating nonheme diiron enzymes, a series of metastable synthetic diiron(III)-peroxo complexes with [FeIII2(µ-O)(µ-1,2-O2)] cores has been characterized by X-ray absorption and resonance Raman spectroscopy. EXAFS analysis shows that this basic core structure gives rise to an Fe-Fe distance of ~3.15 Å; the distance is decreased by 0.1 Å upon introduction of an additional carboxylate bridge. In corresponding resonance Raman studies, vibrations arising from both the Fe-O-Fe and the Fe-O-O-Fe units can be observed. A change in the Fe-Fe distance affects the ν(O-O) mode, as well as the νsym(Fe-O-Fe) and the νasym(Fe-O-Fe) modes. Indeed a linear correlation can be discerned between the ν(O-O) frequency of a complex and its Fe-Fe distance among the subset of complexes with [FeIII2(µ-OR)(µ-1,2-O2)] cores (R = H, alkyl, aryl, or no substituent). These experimental studies are complemented by a normal coordinate analysis and DFT calculations. PMID:18811130

Advanced magnetic resonance imaging in glioblastoma: a review.

PubMed

Shukla, Gaurav; Alexander, Gregory S; Bakas, Spyridon; Nikam, Rahul; Talekar, Kiran; Palmer, Joshua D; Shi, Wenyin

2017-08-01

Glioblastoma, the most common and most rapidly progressing primary malignant tumor of the central nervous system, continues to portend a dismal prognosis, despite improvements in diagnostic and therapeutic strategies over the last 20 years. The standard of care radiographic characterization of glioblastoma is magnetic resonance imaging (MRI), which is a widely utilized examination in the diagnosis and post-treatment management of patients with glioblastoma. Basic MRI modalities available from any clinical scanner, including native T1-weighted (T1w) and contrast-enhanced (T1CE), T2-weighted (T2w), and T2-fluid-attenuated inversion recovery (T2-FLAIR) sequences, provide critical clinical information about various processes in the tumor environment. In the last decade, advanced MRI modalities are increasingly utilized to further characterize glioblastomas more comprehensively. These include multi-parametric MRI sequences, such as dynamic susceptibility contrast (DSC), dynamic contrast enhancement (DCE), higher order diffusion techniques such as diffusion tensor imaging (DTI), and MR spectroscopy (MRS). Significant efforts are ongoing to implement these advanced imaging modalities into improved clinical workflows and personalized therapy approaches. Functional MRI (fMRI) and tractography are increasingly being used to identify eloquent cortices and important tracts to minimize postsurgical neuro-deficits. A contemporary review of the application of standard and advanced MRI in clinical neuro-oncologic practice is presented here.

Spectroscopy and imaging with a 4 tesla whole-body MR system.

PubMed

Bomsdorf, H; Helzel, T; Kunz, D; Röschmann, P; Tschendel, O; Wieland, J

1988-06-01

Magnetic resonance (MR) spectroscopy and imaging experiments on humans were performed with a whole-body MR system at a static field of 4 tesla. Spectroscopic studies focussed on 1H, 13C, and 31P. Imaging of humans turned out to be possible, although below the optimum at this field. This holds especially for body imaging, since RF penetration effects and dielectric resonances influence the RF field homogeneity. Excellent volume selective proton spectra of the human cerebrum and cerebellum were obtained using the stimulated echo method. Natural abundance carbon spectra of the human calf were acquired both undecoupled and with narrowband decoupling, resolving the various triglyceride resonances. Broadband decoupling, however, would have violated SAR guidelines. Liver glycogen was detected on natural abundance 13C spectra.

Spin polarized surface resonance bands in single layer Bi on Ge(1 1 1)

NASA Astrophysics Data System (ADS)

Bottegoni, F.; Calloni, A.; Bussetti, G.; Camera, A.; Zucchetti, C.; Finazzi, M.; Duò, L.; Ciccacci, F.

2016-05-01

The spin features of surface resonance bands in single layer Bi on Ge(1 1 1) are studied by means of spin- and angle-resolved photoemission spectroscopy and inverse photoemission spectroscopy. We characterize the occupied and empty surface states of Ge(1 1 1) and show that the deposition of one monolayer of Bi on Ge(1 1 1) leads to the appearance of spin-polarized surface resonance bands. In particular, the C 3v symmetry, which Bi adatoms adopt on Ge(1 1 1), allows for the presence of Rashba-like occupied and unoccupied electronic states around the \\overline{\\text{M}} point of the Bi surface Brillouin zone with a giant spin-orbit constant |{α\\text{R}}| =≤ft(1.4+/- 0.1\\right) eV · Å.

High-intensity xenon plasma discharge lamp for bulk-sensitive high-resolution photoemission spectroscopy.

PubMed

Souma, S; Sato, T; Takahashi, T; Baltzer, P

2007-12-01

We have developed a highly brilliant xenon (Xe) discharge lamp operated by microwave-induced electron cyclotron resonance (ECR) for ultrahigh-resolution bulk-sensitive photoemission spectroscopy (PES). We observed at least eight strong radiation lines from neutral or singly ionized Xe atoms in the energy region of 8.4-10.7 eV. The photon flux of the strongest Xe I resonance line at 8.437 eV is comparable to that of the He Ialpha line (21.218 eV) from the He-ECR discharge lamp. Stable operation for more than 300 h is achieved by efficient air-cooling of a ceramic tube in the resonance cavity. The high bulk sensitivity and high-energy resolution of PES using the Xe lines are demonstrated for some typical materials.

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.

Observation of Image Potential State in Oxygen Intercalated Graphene on Iridium by Two-Photon-Photoemission Spectroscopy

NASA Astrophysics Data System (ADS)

Lin, Yi; Li, Yunzhe; Sadowski, Jerzy; Dadap, Jerry; Jin, Wencan; Osgood, Richard

In this talk, we report our experimental results on the first direct observation of image potential state (IPS) in oxygen-intercalated graphene on iridium by two-photo-photoemission spectroscopy. We demonstrate how oxygen intercalation influences the IPS in Gr/Ir and decouples the interlayer interaction. We present measurements of the electronic dispersion and work function in pristine Gr/Ir, oxygen-intercalated Gr/O/Ir, and deintercalated Gr/Ir. LEED patterns are measured during the pristine, oxygen-intercalated, and deintercalated phases of the Gr/Ir sample. Based on these measurements, relative to the pristine case, the work function and the energy location of n =1 IPS relative to the Fermi level increases by 0.39 eV and 0.3 eV, respectively, due to oxygen intercalation, whereas the effective mass of n =1 IPS is hardly influenced by the intercalation process. Moreover, we achieve the quenching and restoration of the resonance from Ir Rashba states to n =1 IPS in Gr/Ir by oxygen intercalation and deintercalation. This work was supported by the DOE, Office of Basic Energy Sciences, Division of MSE under Contract No. DE-FG 02-04-ER-46157. This research used resources of the CFN, which is the U.S. DOE Office of Science User Facility, under Contract No. DE-SC0012704.

Neurochemistry in shiverer mouse depicted on MR spectroscopy.

PubMed

Takanashi, Jun-ichi; Nitta, Nobuhiro; Iwasaki, Nobuaki; Saito, Shigeyoshi; Tanaka, Ryuta; Barkovich, A James; Aoki, Ichio

2014-06-01

To evaluate the neurochemical changes associated with hypomyelination, especially to clarify whether increased total N-acetylaspartate (tNAA) with decreased choline (Cho) observed in the thalamus of msd mice with the plp1 mutation is a common finding for hypomyelinating disorders. We performed magnetic resonance imaging (MRI) and proton MR spectroscopy ((1) H-MRS) of the thalamus and cortex of postnatal 12-week shiverer mice devoid of myelin basic protein (mbp), heterozygous and wild-type mice with a 7.0T magnet. Luxol Fast Blue staining and immunohistochemical analysis with anti-Mbp, Gfap, Olig2, and NeuN antibodies were also performed. In the thalamus, decreased Cho and normal tNAA were observed in shiverer mice. In the cortex, tNAA, Cho, and glutamate were decreased in shiverer mice. Histological and immunohistochemical analysis of shiverer mice brains revealed hypomyelination in the thalamus, white matter, and cortex; astrogliosis and an increased number of total oligodendrocytes in the white matter; and a decreased number of neurons in the cortex. The reduction of Cho on (1) H-MRS might be a common marker for hypomyelinating disorders. A normal tNAA level in the thalamus of shiverer mice might be explained by the presence of mature oligodendrocytes, which enable neuron-to-oligodendrocyte NAA transport or NAA catabolism. Copyright © 2013 Wiley Periodicals, Inc.

Spectroscopy, Understanding the Atom Series.

ERIC Educational Resources Information Center

Hellman, Hal

This booklet is one of the "Understanding the Atom" Series. The science of spectroscopy is presented by a number of topics dealing with (1) the uses of spectroscopy, (2) its origin and background, (3) the basic optical systems of spectroscopes, spectrometers, and spectrophotometers, (4) the characteristics of wave motion, (5) the…

Biomolecular imaging of 13C-butyrate with dissolution-DNP: Polarization enhancement and formulation for in vivo studies

NASA Astrophysics Data System (ADS)

Flori, Alessandra; Giovannetti, Giulio; Santarelli, Maria Filomena; Aquaro, Giovanni Donato; De Marchi, Daniele; Burchielli, Silvia; Frijia, Francesca; Positano, Vincenzo; Landini, Luigi; Menichetti, Luca

2018-06-01

Magnetic Resonance Spectroscopy of hyperpolarized isotopically enriched molecules facilitates the non-invasive real-time investigation of in vivo tissue metabolism in the time-frame of a few minutes; this opens up a new avenue in the development of biomolecular probes. Dissolution Dynamic Nuclear Polarization is a hyperpolarization technique yielding a more than four orders of magnitude increase in the 13C polarization for in vivo Magnetic Resonance Spectroscopy studies. As reported in several studies, the dissolution Dynamic Nuclear Polarization polarization performance relies on the chemico-physical properties of the sample. In this study, we describe and quantify the effects of the different sample components on the dissolution Dynamic Nuclear Polarization performance of [1-13C]butyrate. In particular, we focus on the polarization enhancement provided by the incremental addition of the glassy agent dimethyl sulfoxide and gadolinium chelate to the formulation. Finally, preliminary results obtained after injection in healthy rats are also reported, showing the feasibility of an in vivo Magnetic Resonance Spectroscopy study with hyperpolarized [1-13C]butyrate using a 3T clinical set-up.

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

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.

Brain oxygen saturation assessment in neonates using T2-prepared blood imaging of oxygen saturation and near-infrared spectroscopy.

PubMed

Alderliesten, Thomas; De Vis, Jill B; Lemmers, Petra Ma; Hendrikse, Jeroen; Groenendaal, Floris; van Bel, Frank; Benders, Manon Jnl; Petersen, Esben T

2017-03-01

Although near-infrared spectroscopy is increasingly being used to monitor cerebral oxygenation in neonates, it has a limited penetration depth. The T 2 -prepared Blood Imaging of Oxygen Saturation (T 2 -BIOS) magnetic resonance sequence provides an oxygen saturation estimate on a voxel-by-voxel basis, without needing a respiratory calibration experiment. In 15 neonates, oxygen saturation measured by T 2 -prepared blood imaging of oxygen saturation and near-infrared spectroscopy were compared. In addition, these measures were compared to cerebral blood flow and venous oxygen saturation in the sagittal sinus. A strong linear relation was found between the oxygen saturation measured by magnetic resonance imaging and the oxygen saturation measured by near-infrared spectroscopy ( R 2  = 0.64, p < 0.001). Strong linear correlations were found between near-infrared spectroscopy oxygen saturation, and magnetic resonance imaging measures of frontal cerebral blood flow, whole brain cerebral blood flow and venous oxygen saturation in the sagittal sinus ( R 2  = 0.71, 0.50, 0.65; p < 0.01). The oxygen saturation obtained by T 2 -prepared blood imaging of oxygen saturation correlated with venous oxygen saturation in the sagittal sinus ( R 2  = 0.49, p = 0.023), but no significant correlations could be demonstrated with frontal and whole brain cerebral blood flow. These results suggest that measuring oxygen saturation by T 2 -prepared blood imaging of oxygen saturation is feasible, even in neonates. Strong correlations between the various methods work as a cross validation for near-infrared spectroscopy and T 2 -prepared blood imaging of oxygen saturation, confirming the validity of using of these techniques for determining cerebral oxygenation.

Investigation of the basic physics of high efficiency semiconductor hot carrier solar cell

NASA Technical Reports Server (NTRS)

Alfano, R. R.; Wang, W. B.; Mohaidat, J. M.; Cavicchia, M. A.; Raisky, O. Y.

1995-01-01

The main purpose of this research program is to investigate potential semiconductor materials and their multi-band-gap MQW (multiple quantum wells) structures for high efficiency solar cells for aerospace and commercial applications. The absorption and PL (photoluminescence) spectra, the carrier dynamics, and band structures have been investigated for semiconductors of InP, GaP, GaInP, and InGaAsP/InP MQW structures, and for semiconductors of GaAs and AlGaAs by previous measurements. The barrier potential design criteria for achieving maximum energy conversion efficiency, and the resonant tunneling time as a function of barrier width in high efficiency MQW solar cell structures have also been investigated in the first two years. Based on previous carrier dynamics measurements and the time-dependent short circuit current density calculations, an InAs/InGaAs - InGaAs/GaAs - GaAs/AlGaAs MQW solar cell structure with 15 bandgaps has been designed. The absorption and PL spectra in InGaAsP/InP bulk and MQW structures were measured at room temperature and 77 K with different pump wavelength and intensity, to search for resonant states that may affect the solar cell activities. Time-resolved IR absorption for InGaAsP/InP bulk and MQW structures has been measured by femtosecond visible-pump and IR-probe absorption spectroscopy. This, with the absorption and PL measurements, will be helpful to understand the basic physics and device performance in multi-bandgap InAs/InGaAs - InGaAs/InP - InP/InGaP MQW solar cells. In particular, the lifetime of the photoexcited hot electrons is an important parameter for the device operation of InGaAsP/InP MQW solar cells working in the resonant tunneling conditions. Lastly, time evolution of the hot electron relaxation in GaAs has been measured in the temperature range of 4 K through 288 K using femtosecond pump-IR-probe absorption technique. The temperature dependence of the hot electron relaxation time in the X valley has been measured.

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.

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.

In situ nuclear magnetic resonance microimaging of live biofilms in a microchannel

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

Renslow, R. S.; Marshall, M. J.; Tucker, A. E.

Nuclear magnetic resonance (NMR) microimaging and spectroscopy was used to interrogate fluids of biological importance (e.g., water, buffer, medium solution) and live biofilms in a microchannel compatible for analyses at ambient pressure and under vacuum. Studies using buffer, growth medium, and actively growing Shewanella oneidensis biofilms were used to demonstrate in situ NMR microimaging measurement capabilities including velocity mapping, diffusion coefficient mapping, relaxometry, localized spectroscopy, and 2D and 3D imaging within a microchannel suitable for different analytical platforms. This technique is promising for diverse applications of correlative imaging using a portable microfluidic platform.

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.

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.

Detection of elemental mercury by multimode diode laser correlation spectroscopy.

PubMed

Lou, Xiutao; Somesfalean, Gabriel; Svanberg, Sune; Zhang, Zhiguo; Wu, Shaohua

2012-02-27

We demonstrate a method for elemental mercury detection based on correlation spectroscopy employing UV laser radiation generated by sum-frequency mixing of two visible multimode diode lasers. Resonance matching of the multimode UV laser is achieved in a wide wavelength range and with good tolerance for various operating conditions. Large mode-hops provide an off-resonance baseline, eliminating interferences from other gas species with broadband absorption. A sensitivity of 1 μg/m3 is obtained for a 1-m path length and 30-s integration time. The performance of the system shows promise for mercury monitoring in industrial applications.

A 90-Day Oral Toxicity Study and a 5-Day Metabolism Study of Diisopropyl Methylphosphonate (DIMP) in Mink.

DTIC Science & Technology

1992-06-01

characterized with infrared and ultraviolet/visible spectroscopy , nuclear magnetic resonance analysis and gas and thin-layer chromatography. These...comparison gas chromatographic major peak profile of diisopropyl methylphosphonate. In brief, infrared and ultraviolet/visible spectroscopy and nuclear...An aliquot of this batch was analyzed by MRI, Kansas City, MO. The characterization consisted of determination of physical properties, spectroscopy

Inhibition of 53BP1: Potential for Restoring Homologous Recombination In Ovarian Cancer Cells

DTIC Science & Technology

2017-08-01

crystallography ; NMR spectroscopy; Calorimetry 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF RESPONSIBLE...ray crystallography ; NMR spectroscopy; Calorimetry 3. ACCOMPLISHMENTS: The PI is reminded that the recipient organization is required to obtain...originally planned. Each aim combines structural studies using X-ray crystallography or nuclear magnetic resonance (NMR) spectroscopy and functional

Nuclear Magnetic Resonance Technology for Medical Studies.

ERIC Educational Resources Information Center

Budinger, Thomas F.; Lauterbur, Paul C.

1984-01-01

Reports on the status of nuclear magnetic resonance (NMR) from theoretical and clinical perspectives, reviewing NMR theory and relaxation parameters relevant to NMR imaging. Also reviews literature related to modern imaging strategies, signal-to-noise ratio, contrast agents, in vivo spectroscopy, spectroscopic imaging, clinical applications, and…

COMPREHENSIVE PROGRESS REPORT FOR FOURIER TRANSFORM NMR (NUCLEAR MAGNETIC RESONANCE) OF METALS OF ENVIRONMENTAL SIGNIFICANCE

EPA Science Inventory

Interactions of the metals cadmium and selenium with various biologically important substrates were studied by nuclear magnetic resonance (NMR) spectroscopy. Cadmium-113 NMR was used for a critical examination of three metalloproteins: concanavalin A, bovine superoxide dismutase ...

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.

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

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.

Experimental Detection of the Intrinsic Difference in Raman Optical Activity of a Photoreceptor Protein under Preresonance and Resonance Conditions.

PubMed

Haraguchi, Shojiro; Hara, Miwa; Shingae, Takahito; Kumauchi, Masato; Hoff, Wouter D; Unno, Masashi

2015-09-21

Raman optical activity (ROA) is an advanced technique capable of detecting structural deformations of light-absorbing molecules embedded in chromophoric proteins. Resonance Raman (RR) spectroscopy is widely used to enhance the band intensities. However, theoretical work has predicted that under resonance conditions the ROA spectrum resembles the shape of the RR spectrum. Herein, we use photoactive yellow protein (PYP) to measure the first experimental data on the effect of changing the excitation wavelength on the ROA spectra of a protein. We observe a close similarity between the shape of the RR spectrum and the resonance ROA spectrum of PYP. Furthermore, we experimentally verify the theoretical prediction concerning the ratio of the amplitudes of the ROA and Raman spectra. Our data demonstrate that selecting an appropriate excitation wavelength is a key factor for extracting structural information on a protein active site using ROA spectroscopy. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

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

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

Clinical, pathological, and neuroimaging analyses of two cases of Leigh syndrome in a Chinese family.

PubMed

Jin, Taoran; Shen, Hongrui; Zhao, Zhe; Hu, Jing

2014-11-01

In this study, the authors examined the clinical manifestations, skeletal muscle pathological characteristics, and neuroimaging results of 2 cases of Leigh syndrome in a Chinese family. The 2 patients presented with general weakness, and 1 of them presented with an impairment of vision. Skeletal muscle biopsies showed a deficiency in cytochrome c oxidase levels. Brain magnetic resonance imaging showed increased T1 and T2 signal intensities in the centrum ovale and dentate nucleus. Diffusion-weighted imaging showed a high-intensity signal. Magnetic resonance spectroscopy showed elevated levels of lactic acid in lesions. The examination of 1 patient at disease onset and during disease remission showed that the lesions detected by magnetic resonance imaging and diffusion-weighted imaging, and the peak for lactic acid detected by magnetic resonance spectroscopy, decreased during remission. These data suggest that changes in the imaging results of patients with Leigh syndrome correlate with disease course and pathogenetic condition. © The Author(s) 2014.

Enantiodifferentiation through frequency-selective pure-shift (1)H nuclear magnetic resonance spectroscopy.

PubMed

Castañar, Laura; Pérez-Trujillo, Míriam; Nolis, Pau; Monteagudo, Eva; Virgili, Albert; Parella, Teodor

2014-04-04

A frequency-selective 1D (1) H nuclear magnetic resonance (NMR) experiment for the fast and sensitive determination of chemical-shift differences between overlapped resonances is proposed. The resulting fully homodecoupled (1) H NMR resonances appear as resolved 1D singlets without their typical J(HH) coupling constant multiplet structures. The high signal dispersion that is achieved is then exploited in enantiodiscrimination studies by using chiral solvating agents. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Measurement of Solution Viscosity via Diffusion-Ordered NMR Spectroscopy (DOSY)

ERIC Educational Resources Information Center

Li, Weibin; Kagan, Gerald; Hopson, Russell; Williard, Paul G.

2011-01-01

Increasingly, the undergraduate chemistry curriculum includes nuclear magnetic resonance (NMR) spectroscopy. Advanced NMR techniques are often taught including two-dimensional gradient-based experiments. An investigation of intermolecular forces including viscosity, by a variety of methods, is often integrated in the undergraduate physical and…

Optical Spectroscopy Of Charged Quantum Dot Molecules

NASA Astrophysics Data System (ADS)

Scheibner, M.; Bracker, A. S.; Stinaff, E. A.; Doty, M. F.; Gammon, D.; Ponomarev, I. V.; Reinecke, T. L.; Korenev, V. L.

2007-04-01

Coupling between two closely spaced quantum dots is observed by means of photoluminescence spectroscopy. Hole coupling is realized by rational crystal growth and heterostructure design. We identify molecular resonances of different excitonic charge states, including the important case of a doubly charged quantum dot molecule.

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

Wojciech, Blachucki

This work treats of the high energy resolution off-resonant X-ray spectroscopy (HEROS) method of determining the density of unoccupied electronic states in the vicinity of the absorption edge. HEROS is an alternative to the existing X-ray absorption spectroscopy (XAS) methods and opens the way for new studies not achievable before.

Mobile humic acids and recalcitrant calcium humate in eight US soils

USDA-ARS?s Scientific Manuscript database

Both excitation-emission matrix (EEM) fluorescence spectroscopy and solid state C-13 nuclear magnetic resonance (NMR) spectroscopy have been applied for studying soil organic matter (SOM), but rarely have both techniques been employed together. We analyzed the fluorescence features of water extracta...

Lunar sample analysis

NASA Technical Reports Server (NTRS)

Housley, R. M.

1978-01-01

Flameless atomic abosrption, X-ray photoemission spectroscopy, ferromagnetic resonance, scanning electron microscopy, and Moessbauer spectroscopy were used to investigate the evolution of the lunar regolith, the transport of volatile trace metals, and the surface composition of lunar samples. The development of a model for lunar volcanic eruptions is also discussed.

In vitro quantitative ((1))H and ((19))F nuclear magnetic resonance spectroscopy and imaging studies of fluvastatin™ in Lescol® XL tablets in a USP-IV dissolution cell.

PubMed

Zhang, Qilei; Gladden, Lynn; Avalle, Paolo; Mantle, Michael

2011-12-20

Swellable polymeric matrices are key systems in the controlled drug release area. Currently, the vast majority of research is still focused on polymer swelling dynamics. This study represents the first quantitative multi-nuclear (((1))H and ((19))F) fast magnetic resonance imaging study of the complete dissolution process of a commercial (Lescol® XL) tablet, whose formulation is based on the hydroxypropyl methylcellulose (HPMC) polymer under in vitro conditions in a standard USP-IV (United States Pharmacopeia apparatus IV) flow-through cell that is incorporated into high field superconducting magnetic resonance spectrometer. Quantitative RARE ((1))H magnetic resonance imaging (MRI) and ((19))F nuclear magnetic resonance (NMR) spectroscopy and imaging methods have been used to give information on: (i) dissolution media uptake and hydrodynamics; (ii) active pharmaceutical ingredient (API) mobilisation and dissolution; (iii) matrix swelling and dissolution and (iv) media activity within the swelling matrix. In order to better reflect the in vivo conditions, the bio-relevant media Simulated Gastric Fluid (SGF) and Fasted State Simulated Intestinal Fluid (FaSSIF) were used. A newly developed quantitative ultra-fast MRI technique was applied and the results clearly show the transport dynamics of media penetration and hydrodynamics along with the polymer swelling processes. The drug dissolution and mobility inside the gel matrix was characterised, in parallel to the ((1))H measurements, by ((19))F NMR spectroscopy and MRI, and the drug release profile in the bulk solution was recorded offline by UV spectrometer. We found that NMR spectroscopy and 1D-MRI can be uniquely used to monitor the drug dissolution/mobilisation process within the gel layer, and the results from ((19))F NMR spectra indicate that in the gel layer, the physical mobility of the drug changes from "dissolved immobilised drug" to "dissolved mobilised drug". Copyright © 2011 Elsevier B.V. All rights reserved.

Enhanced detection of thiophenol adsorbed on gold nanoparticles by SFG and DFG nonlinear optical spectroscopy.

PubMed

Pluchery, Olivier; Humbert, Christophe; Valamanesh, Mehrnoush; Lacaze, Emmanuelle; Busson, Bertrand

2009-09-21

Sum frequency generation (SFG) and difference frequency generation (DFG) are applied to study vibrational resonance of the thiophenol molecule adsorbed on two different gold samples. One sample is made of 17 nm gold nanoparticles (AuNPs) fixed on a silicon substrate that has been previously functionalized with a silane monolayer (aminopropyltriethoxysilane, APTES). This sample is fully characterized through visible reflection spectroscopy and AFM. The second sample is a gold monocrystal also covered with thiophenol molecules. From their comparison, an enhancement factor of 21 is deduced for the SFG signal on AuNPs with respect to the Au(111), related to the surface plasmon resonance (SPR). From a combined analysis of the SFG and DFG spectra, we demonstrate that SFG/DFG spectroscopy is able to identify the nature of the substrate where the molecules are adsorbed. This opens new perspectives for this nonlinear spectroscopy by adding to its well-known intrinsic surface specificity, the ability to selectively probe the chemical layer capping the AuNPs.

Two dimensional molecular electronics spectroscopy for molecular fingerprinting, DNA sequencing, and cancerous DNA recognition.

PubMed

Rajan, Arunkumar Chitteth; Rezapour, Mohammad Reza; Yun, Jeonghun; Cho, Yeonchoo; Cho, Woo Jong; Min, Seung Kyu; Lee, Geunsik; Kim, Kwang S

2014-02-25

Laser-driven molecular spectroscopy of low spatial resolution is widely used, while electronic current-driven molecular spectroscopy of atomic scale resolution has been limited because currents provide only minimal information. However, electron transmission of a graphene nanoribbon on which a molecule is adsorbed shows molecular fingerprints of Fano resonances, i.e., characteristic features of frontier orbitals and conformations of physisorbed molecules. Utilizing these resonance profiles, here we demonstrate two-dimensional molecular electronics spectroscopy (2D MES). The differential conductance with respect to bias and gate voltages not only distinguishes different types of nucleobases for DNA sequencing but also recognizes methylated nucleobases which could be related to cancerous cell growth. This 2D MES could open an exciting field to recognize single molecule signatures at atomic resolution. The advantages of the 2D MES over the one-dimensional (1D) current analysis can be comparable to those of 2D NMR over 1D NMR analysis.

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.

Probing interfacial characteristics of rubrene/pentacene and pentacene/rubrene bilayers with soft X-ray spectroscopy.

PubMed

Seo, J H; Pedersen, T M; Chang, G S; Moewes, A; Yoo, K-H; Cho, S J; Whang, C N

2007-08-16

The electronic structure of rubrene/pentacene and pentacene/rubrene bilayers has been investigated using soft X-ray absorption spectroscopy, resonant X-ray emission spectroscopy, and density-functional theory calculations. X-ray absorption and emission measurements reveal that it has been possible to alter the lowest unoccupied and the highest occupied molecular orbital states of rubrene in rubrene/pentacene bilayer. In the reverse case, one gets p* molecular orbital states originating from the pentacene layer. Resonant X-ray emission spectra suggest a reduction in the hole-transition probabilities for the pentacene/rubrene bilayer in comparison to reference pentacene layer. For the rubrenepentacene structure, the hole-transition probability shows an increase in comparison to the rubrene reference. We also determined the energy level alignment of the pentacene-rubrene interface by using X-ray and ultraviolet photoelectron spectroscopy. From these comparisons, it is found that the electronic structure of the pentacene-rubrene interface has a strong dependence on interface characteristics which depends on the order of the layers used.

1H NMR quantitative determination of photosynthetic pigments from green beans (Phaseolus vulgaris L.).

PubMed

Valverde, Juan; This, Hervé

2008-01-23

Using 1H nuclear magnetic resonance spectroscopy (1D and 2D), the two types of photosynthetic pigments (chlorophylls, their derivatives, and carotenoids) of "green beans" (immature pods of Phaseolus vulgaris L.) were analyzed. Compared to other analytical methods (light spectroscopy or chromatography), 1H NMR spectroscopy is a fast analytical way that provides more information on chlorophyll derivatives (allomers and epimers) than ultraviolet-visible spectroscopy. Moreover, it gives a large amount of data without prior chromatographic separation.

Perspectives of shaped pulses for EPR spectroscopy

NASA Astrophysics Data System (ADS)

Spindler, Philipp E.; Schöps, Philipp; Kallies, Wolfgang; Glaser, Steffen J.; Prisner, Thomas F.

2017-07-01

This article describes current uses of shaped pulses, generated by an arbitrary waveform generator, in the field of EPR spectroscopy. We show applications of sech/tanh and WURST pulses to dipolar spectroscopy, including new pulse schemes and procedures, and discuss the more general concept of optimum-control-based pulses for applications in EPR spectroscopy. The article also describes a procedure to correct for experimental imperfections, mostly introduced by the microwave resonator, and discusses further potential applications and limitations of such pulses.

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 Veterinary Radiology.

Gas-phase broadband spectroscopy using active sources: progress, status, and applications

PubMed Central

Cossel, Kevin C.; Waxman, Eleanor M.; Finneran, Ian A.; Blake, Geoffrey A.; Ye, Jun; Newbury, Nathan R.

2017-01-01

Broadband spectroscopy is an invaluable tool for measuring multiple gas-phase species simultaneously. In this work we review basic techniques, implementations, and current applications for broadband spectroscopy. We discuss components of broad-band spectroscopy including light sources, absorption cells, and detection methods and then discuss specific combinations of these components in commonly-used techniques. We finish this review by discussing potential future advances in techniques and applications of broad-band spectroscopy. PMID:28630530

Angular Random Walk Estimation of a Time-Domain Switching Micromachined Gyroscope

DTIC Science & Technology

2016-10-19

1 2. PARAMETRIC SYSTEM IDENTIFICATION BASED ON TIME-DOMAIN SWITCHING ........ 2 3. FINITE ELEMENT MODELING OF RESONATOR...8 3. FINITE ELEMENT MODELING OF RESONATOR This section details basic finite element modeling of the resonator used with the TDSMG. While it...Based on finite element simulations of the employed resonator, it is found that the effects of thermomechanical noise is on par with 10 ps of timing

BATSE spectroscopy analysis system

NASA Technical Reports Server (NTRS)

Schaefer, Bradley E.; Bansal, Sandhia; Basu, Anju; Brisco, Phil; Cline, Thomas L.; Friend, Elliott; Laubenthal, Nancy; Panduranga, E. S.; Parkar, Nuru; Rust, Brad

1992-01-01

The Burst and Transient Source Experiment (BATSE) Spectroscopy Analysis System (BSAS) is the software system which is the primary tool for the analysis of spectral data from BATSE. As such, Guest Investigators and the community as a whole need to know its basic properties and characteristics. Described here are the characteristics of the BATSE spectroscopy detectors and the BSAS.

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

Huang X. R.; Siddons D.; Macrander, A.T.

Realization of x-ray Fabry-Perot (FP) resonance in back-Bragg-reflection crystal cavities has been proposed and explored for many years, but to date no satisfactory performance has been achieved. Here we show that single-cavity crystal resonators intrinsically have limited finesse and efficiency. To break this limit, we demonstrate that monolithic multicavity resonators with equal-width cavities and specific plate thickness ratios can generate ultrahigh-resolution FP resonance with high efficiency, steep peak tails, and ultrahigh contrast simultaneously. The resonance mechanism is similar to that of sequentially cascaded single-cavity resonators. The ultranarrow-bandwidth FP resonance is anticipated to have various applications, including modern ultrahigh-resolution or precisionmore » x-ray monochromatization, spectroscopy, coherence purification, coherent diffraction, phase contrast imaging, etc.« less

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.

Ionization cross section, pressure shift and isotope shift measurements of osmium

NASA Astrophysics Data System (ADS)

Hirayama, Yoshikazu; Mukai, Momo; Watanabe, Yutaka; Oyaizu, Michihiro; Ahmed, Murad; Kakiguchi, Yutaka; Kimura, Sota; Miyatake, Hiroari; Schury, Peter; Wada, Michiharu; Jeong, Sun-Chan

2017-11-01

In-gas-cell laser resonance ionization spectroscopy of neutral osmium atoms was performed with the use of a two-color two-step laser resonance ionization technique. Saturation curves for the ionization scheme were measured, and the ionization cross section was experimentally determined by solving the rate equations for the ground, intermediate and ionization continuum populations. The pressure shift and pressure broadening in the resonance spectra of the excitation transition were measured. The electronic factor {F}247 for the transition {λ }1=247.7583 nm to the intermediate state was deduced from the measured isotope shifts of stable {}{188,189,{190,192}}Os isotopes. The efficient ionization scheme, pressure shift, nuclear isotope shift and {F}247 are expected to be useful for applications of laser ion sources to unstable nuclei and for nuclear spectroscopy based on laser ionization techniques.

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.

Self-contained high-pressure cell, apparatus, and procedure for the preparation of encapsulated proteins dissolved in low viscosity fluids for nuclear magnetic resonance spectroscopy

NASA Astrophysics Data System (ADS)

Peterson, Ronald W.; Wand, A. Joshua

2005-09-01

The design of a sample cell for high-performance nuclear magnetic resonance (NMR) at elevated pressure is described. The cell has been optimized for the study of encapsulated proteins dissolved in low viscosity fluids but is suitable for more general nuclear magnetic resonance (NMR) spectroscopy of biomolecules at elevated pressure. The NMR cell is comprised of an alumina-toughened zirconia tube mounted on a self-sealing nonmagnetic metallic valve. The cell has several advantages, including relatively low cost, excellent NMR performance, high-pressure tolerance, chemical inertness, and a relatively large active volume. Also described is a low volume sample preparation device that allows for the preparation of samples under high hydrostatic pressure and their subsequent transfer to the NMR cell.

Resonant tunneling through electronic trapping states in thin MgO magnetic junctions.

PubMed

Teixeira, J M; Ventura, J; Araujo, J P; Sousa, J B; Wisniowski, P; Cardoso, S; Freitas, P P

2011-05-13

We report an inelastic electron tunneling spectroscopy study on MgO magnetic junctions with thin barriers (0.85-1.35 nm). Inelastic electron tunneling spectroscopy reveals resonant electronic trapping within the barrier for voltages V>0.15  V. These trapping features are associated with defects in the barrier crystalline structure, as confirmed by high-resolution transmission electron microscopy. Such defects are responsible for resonant tunneling due to energy levels that are formed in the barrier. A model was applied to determine the average location and energy level of the traps, indicating that they are mostly located in the middle of the MgO barrier, in accordance with the high-resolution transmission electron microscopy data and trap-assisted tunneling conductance theory. Evidence of the influence of trapping on the voltage dependence of tunnel magnetoresistance is shown.

Male Fathead Minnow Urine-Based Metabolomics for Assessing Impacts of Chemical Stressors

EPA Science Inventory

We have developed the potential for profiling metabolites in urine from male fathead minnows (Pimephales promelas) to assess chemical exposures, using nuclear magnetic resonance (NMR) spectroscopy. Both one dimensional (1D) and two dimensional (2D) NMR spectroscopy was us...

Qualitative and quantitative analysis of mixtures of compounds containing both hydrogen and deuterium

NASA Technical Reports Server (NTRS)

Crespi, H. L.; Harkness, L.; Katz, J. J.; Norman, G.; Saur, W.

1969-01-01

Method allows qualitative and quantitative analysis of mixtures of partially deuterated compounds. Nuclear magnetic resonance spectroscopy determines location and amount of deuterium in organic compounds but not fully deuterated compounds. Mass spectroscopy can detect fully deuterated species but not the location.

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

Resonance properties of Ag-ZnO nanostructures at terahertz frequencies

PubMed Central

Sanchez, John E.; Díaz de León, Ramón; Mendoza-Santoyo, Fernando; González, Gabriel; José-Yacaman, Miguel; Ponce, Arturo; González, Francisco Javier

2015-01-01

Nanoantennas have been fabricated by scaling down traditional antenna designs using nanolithographic techniques and testing them at different optical wavelengths, these particular nanoantennas have shown responses in a broad range of frequencies going from visible wavelengths to the range of the terahertz. Some self-assembled nanostructures exist that exhibit similar shapes and properties to those of traditional antenna structures. In this work the emission and absorption properties of self-assembled nanostructures made of zinc oxide nanorods on silver nanowires, which resemble traditional dipole antennas, were measured and simulated in order to test their antenna performance. These structures show resonant properties in the 10-120 THz range, with the main resonance at 60 THz. The radiation pattern of these nanostructures was also obtained by numerical simulations, and it is shown that it can be tailored to increase or decrease its directivity as a function of the location of the energy source of excitation. Experimental measurements were performed by Raman spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR) in order to show existing vibrational frequencies at the resonant frequencies of the nanostructures, measurements were made from ~9 to 103 THz and the results were in agreement with the simulations. These characteristics make these metal-semiconductor Ag/ZnO nanostructures useful as self-assembled nanoantennas in applications such as terahertz spectroscopy and sensing at terahertz frequencies. PMID:26406710

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.

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.

Transport mirages in single-molecule devices

NASA Astrophysics Data System (ADS)

Gaudenzi, R.; Misiorny, M.; Burzurí, E.; Wegewijs, M. R.; van der Zant, H. S. J.

2017-03-01

Molecular systems can exhibit a complex, chemically tailorable inner structure which allows for targeting of specific mechanical, electronic, and optical properties. At the single-molecule level, two major complementary ways to explore these properties are molecular quantum-dot structures and scanning probes. This article outlines comprehensive principles of electron-transport spectroscopy relevant to both these approaches and presents a new, high-resolution experiment on a high-spin single-molecule junction exemplifying these principles. Such spectroscopy plays a key role in further advancing our understanding of molecular and atomic systems, in particular, the relaxation of their spin. In this joint experimental and theoretical analysis, particular focus is put on the crossover between the resonant regime [single-electron tunneling] and the off-resonant regime [inelastic electron (co)tunneling spectroscopy (IETS)]. We show that the interplay of these two processes leads to unexpected mirages of resonances not captured by either of the two pictures alone. Although this turns out to be important in a large fraction of the possible regimes of level positions and bias voltages, it has been given little attention in molecular transport studies. Combined with nonequilibrium IETS—four-electron pump-probe excitations—these mirages provide crucial information on the relaxation of spin excitations. Our encompassing physical picture is supported by a master-equation approach that goes beyond weak coupling. The present work encourages the development of a broader connection between the fields of molecular quantum-dot and scanning probe spectroscopy.

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.

Sub-Thz Vibrational Spectroscopy for Analysis of Ovarian Cancer Cells

NASA Astrophysics Data System (ADS)

Ferrance, Jerome P.; Sizov, Igor; Jazaeri, Amir; Moyer, Aaron; Gelmont, Boris; Globus, Tatiana

2016-06-01

Sub-THz vibrational spectroscopy utilizes wavelengths in the submillimeter-wave range ( 1.5-30 wn), beyond those traditionally used for chemical and biomolecular analysis. This low energy radiation excites low-frequency internal molecular motions (vibrations) involving hydrogen bonds and other weak connections within these molecules. The ability of sub-THz spectroscopy to identify and quantify biological molecules is based on detection of signature resonance absorbance at specific frequencies between 0.05 and 1 THz, for each molecule. The long wavelengths of this radiation, mean that it can even pass through entire cells, detecting the combinations of proteins and nucleic acids that exist within the cell. This research introduces a novel sub-THz resonance spectroscopy instrument with spectral resolution sufficient to identify individual resonance absorption peaks, for the analysis of ovarian cancer cells. In vitro cell cultures of SK-OV-3 and ES-2 cells, two human ovarian cancer subtypes, were characterized and compared with a normal non-transformed human fallopian tube epithelial cell line (FT131). A dramatic difference was observed between the THz absorption spectra of the cancer and normal cell sample materials with much higher absorption intensity and a very strong absorption peak at a frequency of 13 wn dominating the cancer sample spectra. Comparison of experimental spectra with molecular dynamic simulated spectroscopic signatures suggests that the high intensity spectral peak could originate from overexpressed mi-RNA molecules specific for ovarian cancer. Ovarian cancer cells are utilized as a proof of concept, but the sub-THz spectroscopy method is very general and could also be applied to other types of cancer.

Primary granulomatous angiitis of the central nervous system: findings of magnetic resonance spectroscopy and fractional anisotropy in diffusion tensor imaging prior to surgery. Case report.

PubMed

Beppu, Takaaki; Inoue, Takashi; Nishimoto, Hideaki; Nakamura, Shinichi; Nakazato, Yoichi; Ogasawara, Kuniaki; Ogawa, Akira

2007-10-01

Primary granulomatous angiitis of the central nervous system (CNS) is extremely rare. Its preoperative diagnosis is difficult as the condition displays nonspecific features on routine neuroimaging investigations. In this paper, the authors report findings of magnetic resonance (MR) spectroscopy and fractional anisotropy (FA) with diffusion tensor MR imaging in a case of granulomatous angiitis of the CNS. A 30-year-old man presented with morning headaches and grand mal seizures. An MR image revealed a mass resembling glioblastoma in the right temporal lobe. Magnetic resonance spectroscopy showed a high choline/creatine (Cho/Cr) ratio indicative of a malignant neoplasm, accompanied by a slight elevation of glutamate and glutamine. The FA value was very low, which is inconsistent with malignant glioma. The mass was totally removed surgically. Histologically, the peripheral lesion of the mass consisted of a rough accumulation of fat granule cells, infiltration of inflammatory cells, and distribution of capillary vessels. Some vessels within the lesion were replaced by granulomas. The histological diagnosis was granulomatous angiitis of the CNS. The MIB-1-positive rate of the granuloma was approximately 5%. Both MR spectroscopy and FA were unable to accurately diagnose granulomatous angiitis of the CNS prior to surgery; however, elevated Cho/Cr and glutamate and glutamine shown by MR spectroscopy may indicate the moderate proliferation potential of the granuloma and the inflammatory process, respectively, in this condition. Although the low FA value in the present case enabled the authors to rule out a diagnosis of glioblastoma, FA values in inflammatory lesions require careful interpretation.

Indium nanoparticles for ultraviolet surface-enhanced Raman spectroscopy

NASA Astrophysics Data System (ADS)

Das, Rupali; Soni, R. K.

2018-05-01

Ultraviolet Surface-enhanced Raman spectroscopy (UVSERS) has emerged as an efficient molecular spectroscopy technique for ultra-sensitive and ultra-low detection of analyte concentration. The generic SERS substrates based on gold and silver nanostructures have been extensively explored for high local electric field enhancement only in visible-NIR region of the electromagnetic spectrum. The template synthesis of controlled nanoscale size metallic nanostructures supporting localized surface plasmon resonance (LSPR) in the UV region have been recently explored due to their ease of synthesis and potential applications in optoelectronic, catalysis and magnetism. Indium (In0) nanoparticles exhibit active surface plasmon resonance (SPR) in ultraviolet (UV) and deep-ultaviolet (DUV) region with optimal absorption losses. This extended accessibility makes indium a promising material for UV plasmonic, chemical sensing and more recently in UV-SERS. In this work, spherical indium nanoparticles (In NPs) were synthesized by modified polyol reduction method using NaBH4 having local surface plasmon resonance near 280 nm. The as-synthesized spherical In0 nanoparticles were then coated with thin silica shells of thickness ˜ 5nm by a modified Stober method protecting the nanoparticles from agglomeration, direct contact with the probed molecules as well as prevent oxidation of the nanoparticles. Morphological evolution of In0 nanoparticles and SiO2 coating were characterized by transmission electron microscope (TEM). An enhanced near resonant shell-isolated SERS activity from thin film of tryptophan (Tryp) molecules deposited on indium coated substrates under 325nm UV excitation was observed. Finite difference time domain (FDTD) method is employed to comprehend the experimental results and simulate the electric field contours which showed amplified electromagnetic field localized around the nanostructures. The comprehensive analysis indicates that indium is a promising alternate exogenous contrast agent for efficient Raman spectroscopy from molecules.

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

Investigation of radiosterilization feasibility of sulfamethoxazole by ESR spectroscopy

NASA Astrophysics Data System (ADS)

Çolak, Şeyda

2017-12-01

In the present study, the spectroscopic features of the radiolytic intermediates that were produced in gamma-irradiated (5, 10, 25 and 50 kGy) sulfamethoxazole (SMX) have been investigated by electron spin resonance (ESR) spectroscopy and the radiation sterilization feasibility of SMX by ionizing radiation was examined. Gamma-irradiated SMX exhibited a complex ESR spectrum consisting of 13 resonance lines where spectral parameters for the central resonance line were found to be g = 2.0062 and ΔHpp = 0.6 mT. The radiation yield of SMX was calculated to be relatively low (G = 0.1) by ESR spectroscopy and no meaningful difference was observed in the comparison of unirradiated and 50 kGy gamma irradiated SMX by the Fourier transform infrared (FT-IR) technique, confirming that SMX is a radioresistive material. Although SMX could not be accepted to be a good dosimetric material, the identification of irradiated SMX from the unirradiated sample was possible even for the low absorbed radiation doses and for a relatively long time (three months) after the irradiation process. Decay activation energy of the radical species, which is mostly responsible for the central intense resonance line, is calculated to be 45.15 kJ/mol by using the signal intensity decay data derived from annealing studies. Four radical species with different spectroscopic properties were accepted to be responsible for the ESR spectra of gamma-irradiated SMX, by simulation calculations. It is concluded that SMX and SMX-containing drugs can be sterilized by gamma radiation and ESR spectroscopy is an appropriate technique for the characterization of these induced radical intermediates during the gamma irradiation process of SMX. Toxicology tests should also be done for its safe usage.

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.

Using solid 13C NMR coupled with solution 31P NMR spectroscopy to investigate molecular species and lability of organic carbon and phosphorus from aquatic plants in Tai Lake, China

USDA-ARS?s Scientific Manuscript database

Aquatic plants are involved in the storage and release capacity for organic matter and nutrients. In this study, solid 13C and solution 31P nuclear magnetic resonance (NMR) spectroscopy were used to characterize the biomass samples of six aquatic plants. Solid 13C NMR spectroscopy revealed the domin...

Trispyrazolylborate Complexes: An Advanced Synthesis Experiment Using Paramagnetic NMR, Variable-Temperature NMR, and EPR Spectroscopies

ERIC Educational Resources Information Center

Abell, Timothy N.; McCarrick, Robert M.; Bretz, Stacey Lowery; Tierney, David L.

2017-01-01

A structured inquiry experiment for inorganic synthesis has been developed to introduce undergraduate students to advanced spectroscopic techniques including paramagnetic nuclear magnetic resonance and electron paramagnetic resonance. Students synthesize multiple complexes with unknown first row transition metals and identify the unknown metals by…

Magnetically driven oscillator and resonance: a teaching tool

NASA Astrophysics Data System (ADS)

Erol, M.; Çolak, İ. Ö.

2018-05-01

This paper reports a simple magnetically driven oscillator, designed and resolved in order to achieve a better student understanding and to overcome certain instructional difficulties. The apparatus is mainly comprised of an ordinary spring pendulum with a neodymium magnet attached to the bottom, a coil placed in the same vertical direction, an ordinary function generator, an oscilloscope and a smartphone. Driven oscillation and resonance is basically managed by applying a sinusoidal voltage to the coil and tuning the driving frequency to the natural frequency of the pendulum. The resultant oscillation is recorded by a smartphone video application and analyzed via a video analysis programme. The designed apparatus can easily be employed in basic physics laboratories to achieve an enhanced and deeper understanding of driven oscillation and resonance.

Enhancing the low frequency THz resonances (< 1 THz) of organic molecules via electronegative atom substitution

NASA Astrophysics Data System (ADS)

Dash, Jyotirmayee; Ray, Shaumik; Pesala, Bala

2015-03-01

Terahertz (THz) technology is an active area of research with various applications in non-intrusive imaging and spectroscopy. Very few organic molecules have significant resonances below 1 THz. Understanding the origin of low frequency THz modes in these molecules and their absence in other molecules could be extremely important in design and engineering molecules with low frequency THz resonances. These engineered molecules can be used as THz tags for anti-counterfeiting applications. Studies show that low frequency THz resonances are commonly observed in molecules having higher molecular mass and weak intermolecular hydrogen bonds. In this paper, we have explored the possibility of enhancing the strength of THz resonances below 1 THz through electronegative atom substitution. Adding an electronegative atom helps in achieving higher hydrogen bond strength to enhance the resonances below 1 THz. Here acetanilide has been used as a model system. THz-Time Domain Spectroscopy (THz-TDS) results show that acetanilide has a small peak observed below 1 THz. Acetanilide can be converted to 2-fluoroacetanilide by adding an electronegative atom, fluorine, which doesn't have any prominent peak below 1 THz. However, by optimally choosing the position of the electronegative atom as in 4-fluoroacetanilide, a significant THz resonance at 0.86 THz is observed. The origin of low frequency resonances can be understood by carrying out Density Functional Theory (DFT) simulations of full crystal structure. These studies show that adding an electronegative atom to the organic molecules at an optimized position can result in significantly enhanced resonances below 1 THz.

Optical assessment of skin carotenoid status as a biomarker of vegetable and fruit intake

USDA-ARS?s Scientific Manuscript database

Resonance Raman spectroscopy (RRS) and reflection spectroscopy (RS) are optical methods applicable to the non-invasive detection of carotenoids in human skin. RRS is the older, more thoroughly validated method, whereas RS is newer and has several advantages. Since collective skin carotenoid levels...

NMR ANALYSIS OF MALE FATHEAD MINNOW URINARY METABOLITES: A POTENTIAL APPROACH FOR STUDYING IMPACTS OF CHEMICAL EXPOSURES

EPA Science Inventory

The potential for profiling endogenous metabolites in urine from male fathead minnows (Pimephales promelas) to assess chemical exposures was explored using nuclear magnetic resonance (NMR) spectroscopy. Both one dimensional (1D) and two dimensional (2D) NMR spectroscopy w...

Modern Spectroscopy

ERIC Educational Resources Information Center

Barrow, Gordon M.

1970-01-01

Presents the basic ideas of modern spectroscopy. Both the angular momenta and wave-nature approaches to the determination of energy level patterns for atomic and molecular systems are discussed. The interpretation of spectra, based on atomic and molecular models, is considered. (LC)

Phase Acrobatics: The Influence of Excitonic Resonance and Gold Nonresonant Background on Heterodyne-Detected Vibrational Sum Frequency Generation Emission.

PubMed

Rich, Christopher C; Lindberg, Kathryn A; Krummel, Amber T

2017-04-06

We show how heterodyne-detected vibrational sum frequency generation (HD-VSFG) spectroscopy can discriminate between the excitonic and monomeric properties of a helical, nanotube molecular aggregate by monitoring the phase of the VSFG emission associated with different polarization configurations. By keeping track of the "phase acrobatics" associated with the added phase of the nonresonant SFG emission of gold as well as that of the double-resonance conditions achieved when the SF frequency is resonant with an electronic exciton transition, we discover that for aggregates of tetra(sulfonatophenyl)porphyrin (TSPP) the PPP-polarized spectra exhibit double-resonance conditions while SSP-polarized spectra exhibit resonance only with the ground-state vibration. Along with observed shifts in the vibrational frequency, intensity differences, and sign flips in the imaginary second-order susceptibility, χ s,Im (2) , we conclude that PPP-polarized HD-VSFG spectra reflect the delocalized, excitonic nature of the molecular aggregate, while the SSP-polarized HD-VSFG spectra measure the localized, monomeric nature of the molecular subunits. It is implied from this study that HD-VSFG spectroscopy can be uniquely utilized to measure the excitonic and monomeric properties associated with molecular assemblies for a single sample.

Effective approach to spectroscopy and spectral analysis techniques using Matlab

NASA Astrophysics Data System (ADS)

Li, Xiang; Lv, Yong

2017-08-01

With the development of electronic information, computer and network, modern education technology has entered new era, which would give a great impact on teaching process. Spectroscopy and spectral analysis is an elective course for Optoelectronic Information Science and engineering. The teaching objective of this course is to master the basic concepts and principles of spectroscopy, spectral analysis and testing of basic technical means. Then, let the students learn the principle and technology of the spectrum to study the structure and state of the material and the developing process of the technology. MATLAB (matrix laboratory) is a multi-paradigm numerical computing environment and fourth-generation programming language. A proprietary programming language developed by MathWorks, MATLAB allows matrix manipulations, plotting of functions and data, Based on the teaching practice, this paper summarizes the new situation of applying Matlab to the teaching of spectroscopy. This would be suitable for most of the current school multimedia assisted teaching

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.

Vibrational frequencies of anti-diabetic drug studied by terahertz time-domain spectroscopy

NASA Astrophysics Data System (ADS)

Du, S. Q.; Li, H.; Xie, L.; Chen, L.; Peng, Y.; Zhu, Y. M.; Li, H.; Dong, P.; Wang, J. T.

2012-04-01

By using terahertz time-domain spectroscopy, the absorption spectra of seven anti-diabetic pills have been investigated. For gliquidone, glipizide, gliclazide, and glimepiride, an obvious resonance peak is found at 1.37 THz. Furthermore, to overcome the limit of density functional theory that can analyze the normal mode frequencies of the ground state of organic material, we also present a method that relies on pharmacophore recognition, from which we can obtain the resonance peak at 1.37 THz can be attributed to the vibration of sulfonylurea group. The results indicate that the veracity of density functional theory can be increased by combining pharmacophore recognition.

Terahertz time-domain magnetospectroscopy of a high-mobility two-dimensional electron gas.

PubMed

Wang, Xiangfeng; Hilton, David J; Ren, Lei; Mittleman, Daniel M; Kono, Junichiro; Reno, John L

2007-07-01

We have observed cyclotron resonance in a high-mobility GaAs/AlGaAs two-dimensional electron gas by using the techniques of terahertz time-domain spectroscopy combined with magnetic fields. From this, we calculate the real and imaginary parts of the diagonal elements of the magnetoconductivity tensor, which in turn allows us to extract the concentration, effective mass, and scattering time of the electrons in the sample. We demonstrate the utility of ultrafast terahertz spectroscopy, which can recover the true linewidth of cyclotron resonance in a high-mobility (>10(6) cm(2)V(-1)s(-1)) sample without being affected by the saturation effect.

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.

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.

Real-time investigation of cytochrome c release profiles in living neuronal cells undergoing amyloid beta oligomer-induced apoptosis

NASA Astrophysics Data System (ADS)

Lee, Jae Young; Park, Younggeun; Pun, San; Lee, Sung Sik; Lo, Joe F.; Lee, Luke P.

2015-06-01

Intracellular Cyt c release profiles in living human neuroblastoma undergoing amyloid β oligomer (AβO)-induced apoptosis, as a model Alzheimer's disease-associated pathogenic molecule, were analysed in a real-time manner using plasmon resonance energy transfer (PRET)-based spectroscopy.Intracellular Cyt c release profiles in living human neuroblastoma undergoing amyloid β oligomer (AβO)-induced apoptosis, as a model Alzheimer's disease-associated pathogenic molecule, were analysed in a real-time manner using plasmon resonance energy transfer (PRET)-based spectroscopy. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr02390d

Quantum Interference Effects in Resonant Raman Spectroscopy of Single- and Triple-Layer MoTe2 from First-Principles

NASA Astrophysics Data System (ADS)

Miranda, Henrique P. C.; Reichardt, Sven; Froehlicher, Guillaume; Molina-Sánchez, Alejandro; Berciaud, Stéphane; Wirtz, Ludger

2017-04-01

We present a combined experimental and theoretical study of resonant Raman spectroscopy in single- and triple-layer MoTe$_2$. Raman intensities are computed entirely from first principles by calculating finite differences of the dielectric susceptibility. In our analysis, we investigate the role of quantum interference effects and the electron-phonon coupling. With this method, we explain the experimentally observed intensity inversion of the $A^\\prime_1$ vibrational modes in triple-layer MoTe2 with increasing laser photon energy. Finally, we show that a quantitative comparison with experimental data requires the proper inclusion of excitonic effects.

Surface layering and melting in an ionic liquid studied by resonant soft X-ray reflectivity

PubMed Central

Mezger, Markus; Ocko, Benjamin M.; Reichert, Harald; Deutsch, Moshe

2013-01-01

The molecular-scale structure of the ionic liquid [C18mim]+[FAP]− near its free surface was studied by complementary methods. X-ray absorption spectroscopy and resonant soft X-ray reflectivity revealed a depth-decaying near-surface layering. Element-specific interfacial profiles were extracted with submolecular resolution from energy-dependent soft X-ray reflectivity data. Temperature-dependent hard X-ray reflectivity, small- and wide-angle X-ray scattering, and infrared spectroscopy uncovered an intriguing melting mechanism for the layered region, where alkyl chain melting drove a negative thermal expansion of the surface layer spacing. PMID:23431181

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.

X-ray photoelectron spectroscopy and paramagnetic resonance evidence for shock-induced intramolecular bond breaking in some energetic solids

NASA Astrophysics Data System (ADS)

Owens, F. J.; Sharma, J.

1980-03-01

Solid samples of 1,3,5, trinitro 1,3,5, triazacyclohexane (RDX), trinitrotoluene (TNT), and ammonium nitrate were subjected to shock pulses of strength and duration less than the threshold to cause detonation. The recovered shocked samples were studied by x-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR). The results of these measurements indicate that the shock pulse either broke or altered the internal bonds of the molecules of the solid. The results of the shock decomposition are compared with measurements of the uv and slow thermal decomposition of these materials using the same experimental techniques.

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.

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).

Spectroscopic characterization of (57)Fe-enriched cytochrome c.

PubMed

Leu, Bogdan M; Ching, Tom H; Tran, Cuong; Sage, J Timothy

2012-04-01

Investigation of the heme iron dynamics in cytochrome c with Mössbauer spectroscopy and especially nuclear resonance vibrational spectroscopy requires the replacement of the natural abundant heme iron with the (57)Fe isotope. For demetallization, we use a safer and milder ferrous sulfate-hydrochloric acid method in addition to the harsher commonly used hydrofluoric acid-based procedure. The structural integrity of the (57)Fe-reconstituted protein in both oxidation states is confirmed from absorption spectra and a detailed analysis of the rich resonance Raman spectra. These results reinforce the application of metal-substituted heme c proteins as reliable models for the native proteins. Published by Elsevier Inc.

Oxide films state analysis by IR spectroscopy based on the simple oscillator approximation

NASA Astrophysics Data System (ADS)

Volkov, N. V.; Yakutkina, T. V.; Karpova, V. V.

2017-05-01

Stabilization of structure-phase state in a wide temperature range is one of the most important problems of improving properties of oxide compounds. As such, the search of new effective methods for obtaining metal oxides with desired physic-chemical, electro-physical and thermal properties and their control is important and relevant. The aim of this work is identification features state of the oxide films of some metals Be, Al, Fe, Cu, Zr on the metal surface of the polycrystalline samples by infrared spectroscopy. To identify the resonance emission bands the algorithm of IR-spectra processing was developed and realized on the basis of table processor EXCEL-2010, which allow revealing characteristic resonance bands successfully and identification of inorganic chemical compounds. In the frame of simple oscillator model, resonance frequencies of normal vibrations of water and some inorganic compounds: metal oxides - Be, Al, Fe, Cu, Zr were calculated and characteristic frequencies for different states (aggregate, deformation, phase) were specified. By means of IR-spectroscopy fundamental possibility of revealing oxides films on metal substrate features state is shown, that allow development and optimization of the technology for production of the oxide films with desired properties.

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

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.

On the contribution of circumferential resonance modes in acoustic radiation force experienced by cylindrical shells

NASA Astrophysics Data System (ADS)

Rajabi, Majid; Behzad, Mehdi

2014-10-01

A body insonified by a constant (time-varying) intensity sound field is known to experience a steady (oscillatory) force that is called the steady-state (dynamic) acoustic radiation force. Using the classical resonance scattering theorem (RST) which suggests the scattered field as a superposition of a resonance field and a background (non-resonance) component, we show that the radiation force acting on a cylindrical shell may be synthesized as a composition of three components: background part, resonance part and their interaction. The background component reveals the pure geometrical reflection effects and illustrates a regular behavior with respect to frequency, while the others demonstrate a singular behavior near the resonance frequencies. The results illustrate that the resonance effects associated to partial waves can be isolated by the subtraction of the background component from the total (steady-state or dynamic) radiation force function (i.e., residue component). In the case of steady-state radiation force, the components are exerted on the body as static forces. For the case of oscillatory amplitude excitation, the components are exerted at the modulation frequency with frequency-dependant phase shifts. The results demonstrate the dominant contribution of the non-resonance component of dynamic radiation force at high frequencies with respect to the residue component, which offers the potential application of ultrasound stimulated vibro-acoustic spectroscopy technique in low frequency resonance spectroscopy purposes. Furthermore, the proposed formulation may be useful essentially due to its intrinsic value in physical acoustics. In addition, it may unveil the contribution of resonance modes in the dynamic radiation force experienced by the cylindrical objects and its underlying physics.

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 + Lac):Cr ratio was significantly elevated within each HIV-positive subgroup compared with seronegative controls. Within HIV-positive patients receiving HAART, the degree of central nervous system penetration (high vs low) did not affect metabolic ratios. As seen with 2-dimensional-chemical shift imaging magnetic resonance spectroscopy, HIV induces inflammation and oxidative stress in HIV-positive patients despite HAART. Lipid and Lac are more sensitive inflammatory biomarkers that may be used to differentiate HIV-positive subgroups. However, no significant difference in efficacy, as measured by metabolic ratios, exists for high- vs low-central nervous system-penetrating HAART.

Acoustic resonance phase locked photoacoustic spectrometer

DOEpatents

Pilgrim, Jeffrey S.; Bomse, David S.; Silver, Joel A.

2003-08-19

A photoacoustic spectroscopy method and apparatus for maintaining an acoustic source frequency on a sample cell resonance frequency comprising: providing an acoustic source to the sample cell to generate a photoacoustic signal, the acoustic source having a source frequency; continuously measuring detection phase of the photoacoustic signal with respect to source frequency or a harmonic thereof; and employing the measured detection phase to provide magnitude and direction for correcting the source frequency to the resonance frequency.

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

Resonant Optical Gradient Force Interaction for Nano-Imaging and-Spectroscopy

DTIC Science & Technology

2016-07-19

frequency dependence of the optically induced force is often explored in optical trapping ofmicro-/ nanoparticles [5, 26–32], and in the optically...reduced to an image sphere of radius r, as shown infigure 1(a). This coupled nanoparticle geometry has been used extensively andwith great success...methylemethacrylate) (PMMA)with characteristic carbonyl resonance (C=O) at 1729 cm−1. Finally, to study the case of plasmonic resonance, two silver spheres

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.

Separating hyperfine from spin-orbit interactions in organic semiconductors by multi-octave magnetic resonance using coplanar waveguide microresonators

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

Joshi, G.; Miller, R.; Ogden, L.

2016-09-05

Separating the influence of hyperfine from spin-orbit interactions in spin-dependent carrier recombination and dissociation processes necessitates magnetic resonance spectroscopy over a wide range of frequencies. We have designed compact and versatile coplanar waveguide resonators for continuous-wave electrically detected magnetic resonance and tested these on organic light-emitting diodes. By exploiting both the fundamental and higher-harmonic modes of the resonators, we cover almost five octaves in resonance frequency within a single setup. The measurements with a common π-conjugated polymer as the active material reveal small but non-negligible effects of spin-orbit interactions, which give rise to a broadening of the magnetic resonance spectrummore » with increasing frequency.« less

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.

Total angular momenta of high-lying odd levels of U I at ∼ 4 eV using resonance ionization laser polarization spectroscopy

NASA Astrophysics Data System (ADS)

Rath, Asawari D.; Kundu, S.; Ray, A. K.

2018-02-01

Laser induced photoionization of atoms shows significant dependence on the choice of polarizations of lasers. In multi-step, multi-photon excitation and subsequent ionization of atoms different polarization combinations of the exciting lasers lead to distinctly different ion yields. This fact is exploited in this work to determine total angular momenta of odd-parity energy levels of U I lying at ∼ 4 eV from its ground level using resonance ionization laser polarization spectroscopy in time of flight mass spectrometer. These levels are populated by two-step resonant excitation using two pulsed dye lasers with preset polarizations of choice followed by nonresonant ionization by third laser. The dependence of ionization yield on specific polarizations of the first two lasers is studied experimentally for each level under consideration. This dependence when compared to simulations makes possible unambiguous assignment of J angular momenta to these levels.

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.

Flexible and stackable terahertz metamaterials via silver-nanoparticle inkjet printing

NASA Astrophysics Data System (ADS)

Kashiwagi, K.; Xie, L.; Li, X.; Kageyama, T.; Miura, M.; Miyashita, H.; Kono, J.; Lee, S.-S.

2018-04-01

There is presently much interest in tunable, flexible, or reconfigurable metamaterial structures that work in the terahertz frequency range. They can be useful for a range of applications, including spectroscopy, sensing, imaging, and communications. Various methods based on microelectromechanical systems have been used for fabricating terahertz metamaterials, but they typically require high-cost facilities and involve a number of time-consuming and intricate processes. Here, we demonstrate a simple, robust, and cost-effective method for fabricating flexible and stackable multiresonant terahertz metamaterials, using silver nanoparticle inkjet printing. Using this method, we designed and fabricated two arrays of split-ring resonators (SRRs) having different resonant frequencies on separate sheets of paper and then combined the two arrays by stacking. Through terahertz time-domain spectroscopy, we observed resonances at the frequencies expected for the individual SRR arrays as well as at a new frequency due to coupling between the two SRR arrays.

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.).

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

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.

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.

Multi-wavelength Raman spectroscopy study of supported vanadia catalysts: Structure identification and quantification

DOE PAGES

Wu, Zili

2014-10-20

Revealing the structure of supported metal oxide catalysts is a prerequisite for establishing the structure - catalysis relationship. Among a variety of characterization techniques, multi-wavelength Raman spectroscopy, combining resonance Raman and non-resonance Raman with different excitation wavelengths, has recently emerged as a particularly powerful tool in not only identifying but also quantifying the structure of supported metal oxide clusters. In our review, we make use of two supported vanadia systems, VO x/SiO 2 and VO x/CeO 2, as examples to showcase how one can employ this technique to investigate the heterogeneous structure of active oxide clusters and to understand themore » complex interaction between the oxide clusters and the support. Moreover, the qualitative and quantitative structural information gained from the multi-wavelength Raman spectroscopy can be utilized to provide fundamental insights for designing more efficient supported metal oxide catalysts.« less

Rapid Catalyst Capture Enables Metal-Free para-Hydrogen-Based Hyperpolarized Contrast Agents.

PubMed

Barskiy, Danila A; Ke, Lucia A; Li, Xingyang; Stevenson, Vincent; Widarman, Nevin; Zhang, Hao; Truxal, Ashley; Pines, Alexander

2018-05-10

Hyperpolarization techniques based on the use of para-hydrogen provide orders of magnitude signal enhancement for magnetic resonance spectroscopy and imaging. The main drawback limiting widespread applicability of para-hydrogen-based techniques in biomedicine is the presence of organometallic compounds (the polarization transfer catalysts) in solution with hyperpolarized contrast agents. These catalysts are typically complexes of platinum-group metals, and their administration in vivo should be avoided. Herein, we show how extraction of a hyperpolarized compound from an organic phase to an aqueous phase combined with a rapid (less than 10 s) Ir-based catalyst capture by metal scavenging agents can produce pure para-hydrogen-based hyperpolarized contrast agents, as demonstrated by high-resolution nuclear magnetic resonance (NMR) spectroscopy and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The presented methodology enables fast and efficient means of producing pure hyperpolarized aqueous solutions for biomedical and other uses.

Photoionization and ion cyclotron resonance studies of the ion chemistry of ethylene oxide

NASA Technical Reports Server (NTRS)

Corderman, R. R.; Williamson, A. D.; Lebreton, P. R.; Buttrill, S. E., Jr.; Beauchamp, J. L.

1976-01-01

The formation of the ethylene oxide molecular ion and its subsequent ion-molecule reactions leading to the products C2H5O(+) and C3H5O(+) have been studied using time-resolved photoionization mass spectroscopy, ion cyclotron resonance spectroscopy, and photoelectron spectroscopy. An examination of the effects of internal energy on reactivity shows that the ratio of C3H5O(+) to C2H5O(+) increases by an order of magnitude with a single quantum of vibrational energy. The formation of (C2H4O/+/)-asterisk in a collision-induced isomerization is found which yields a ring-opened structure by C-C bond cleavage. The relaxed ring-opened C2H4O(+) ion reacts with neutral ethylene oxide by CH2(+) transfer to yield an intermediate product ion C3H6O(+) which gives C3H5O(+) by loss of H.

Fuji apple storage time rapid determination method using Vis/NIR spectroscopy.

PubMed

Liu, Fuqi; Tang, Xuxiang

2015-01-01

Fuji apple storage time rapid determination method using visible/near-infrared (Vis/NIR) spectroscopy was studied in this paper. Vis/NIR diffuse reflection spectroscopy responses to samples were measured for 6 days. Spectroscopy data were processed by stochastic resonance (SR). Principal component analysis (PCA) was utilized to analyze original spectroscopy data and SNR eigen value. Results demonstrated that PCA could not totally discriminate Fuji apples using original spectroscopy data. Signal-to-noise ratio (SNR) spectrum clearly classified all apple samples. PCA using SNR spectrum successfully discriminated apple samples. Therefore, Vis/NIR spectroscopy was effective for Fuji apple storage time rapid discrimination. The proposed method is also promising in condition safety control and management for food and environmental laboratories.

Fuji apple storage time rapid determination method using Vis/NIR spectroscopy

PubMed Central

Liu, Fuqi; Tang, Xuxiang

2015-01-01

Fuji apple storage time rapid determination method using visible/near-infrared (Vis/NIR) spectroscopy was studied in this paper. Vis/NIR diffuse reflection spectroscopy responses to samples were measured for 6 days. Spectroscopy data were processed by stochastic resonance (SR). Principal component analysis (PCA) was utilized to analyze original spectroscopy data and SNR eigen value. Results demonstrated that PCA could not totally discriminate Fuji apples using original spectroscopy data. Signal-to-noise ratio (SNR) spectrum clearly classified all apple samples. PCA using SNR spectrum successfully discriminated apple samples. Therefore, Vis/NIR spectroscopy was effective for Fuji apple storage time rapid discrimination. The proposed method is also promising in condition safety control and management for food and environmental laboratories. PMID:25874818

Recent progress in structural biology: lessons from our research history.

PubMed

Nitta, Ryo; Imasaki, Tsuyoshi; Nitta, Eriko

2018-05-16

The recent 'resolution revolution' in structural analyses of cryo-electron microscopy (cryo-EM) has drastically changed the research strategy for structural biology. In addition to X-ray crystallography and nuclear magnetic resonance spectroscopy, cryo-EM has achieved the structural analysis of biological molecules at near-atomic resolution, resulting in the Nobel Prize in Chemistry 2017. The effect of this revolution has spread within the biology and medical science fields affecting everything from basic research to pharmaceutical development by visualizing atomic structure. As we have used cryo-EM as well as X-ray crystallography since 2000 to elucidate the molecular mechanisms of the fundamental phenomena in the cell, here we review our research history and summarize our findings. In the first half of the review, we describe the structural mechanisms of microtubule-based motility of molecular motor kinesin by using a joint cryo-EM and X-ray crystallography method. In the latter half, we summarize our structural studies on transcriptional regulation by X-ray crystallography of in vitro reconstitution of a multi-protein complex.

Disorder induced spin coherence in polyfluorene thin film semiconductors

NASA Astrophysics Data System (ADS)

Miller, Richard G.; van Schooten, Kipp; Malissa, Hans; Waters, David P.; Lupton, John M.; Boehme, Christoph

2014-03-01

Charge carrier spins in polymeric organic semiconductors significantly influence magneto-optoelectronic properties of these materials. In particular, spin relaxation times influence magnetoresistance and electroluminescence. We have studied the role of structural and electronic disorder in polaron spin-relaxation times. As a model polymer, we used polyfluorene, which can exist in two distinct morphologies: an amorphous (glassy) and an ordered (beta) phase. The phases can be controlled in thin films by preparation parameters and verified by photoluminescence spectroscopy. We conducted pulsed electrically detected magnetic resonance (pEDMR) measurements to determine spin-dephasing times by transient current measurements under bipolar charge carrier injection conditions and a forward bias. The measurements showed that, contrary to intuition, spin-dephasing times increase with material disorder. We attribute this behavior to a reduction in hyperfine field strength for carriers in the glassy phase due to increased structural disorder in the hydrogenated side chains, leading to longer spin coherence times. We acknowledge support by the Department of Energy, Office of Basic Energy Sciences under Award #DE-SC0000909.

Tetrahelical structural family adopted by AGCGA-rich regulatory DNA regions

NASA Astrophysics Data System (ADS)

Kocman, Vojč; Plavec, Janez

2017-05-01

Here we describe AGCGA-quadruplexes, an unexpected addition to the well-known tetrahelical families, G-quadruplexes and i-motifs, that have been a focus of intense research due to their potential biological impact in G- and C-rich DNA regions, respectively. High-resolution structures determined by solution-state nuclear magnetic resonance (NMR) spectroscopy demonstrate that AGCGA-quadruplexes comprise four 5'-AGCGA-3' tracts and are stabilized by G-A and G-C base pairs forming GAGA- and GCGC-quartets, respectively. Residues in the core of the structure are connected with edge-type loops. Sequences of alternating 5'-AGCGA-3' and 5'-GGG-3' repeats could be expected to form G-quadruplexes, but are shown herein to form AGCGA-quadruplexes instead. Unique structural features of AGCGA-quadruplexes together with lower sensitivity to cation and pH variation imply their potential biological relevance in regulatory regions of genes responsible for basic cellular processes that are related to neurological disorders, cancer and abnormalities in bone and cartilage development.

Ubiquitin Utilizes an Acidic Surface Patch to Alter Chromatin Structure

PubMed Central

Debelouchina, Galia T.; Gerecht, Karola; Muir, Tom W.

2016-01-01

Ubiquitylation of histone H2B, associated with gene activation, leads to chromatin decompaction through an unknown mechanism. We used a hydrogen-deuterium exchange strategy coupled with nuclear magnetic resonance spectroscopy to map the ubiquitin surface responsible for its structural effects on chromatin. Our studies revealed that a previously uncharacterized acidic patch on ubiquitin comprising residues Glu16 and Glu18 is essential for decompaction. These residues mediate promiscuous electrostatic interactions with the basic histone proteins, potentially positioning the ubiquitin moiety as a dynamic “wedge” that prevents the intimate association of neighboring nucleosomes. Using two independent cross-linking strategies and an oligomerization assay, we also showed that ubiquitin-ubiquitin contacts occur in the chromatin environment and are important for the solubilization of the chromatin polymers. Our work highlights a novel, chromatin-related aspect of the “ubiquitin code”, and sheds light on how the information rich ubiquitin modification can orchestrate different biochemical outcomes using different surface features. PMID:27870837

Molecular mechanism of Mg2+-dependent gating in CorA

NASA Astrophysics Data System (ADS)

Dalmas, Olivier; Sompornpisut, Pornthep; Bezanilla, Francisco; Perozo, Eduardo

2014-04-01

CorA is the major transport system responsible for Mg2+ uptake in bacteria and can functionally substitute for its homologue Mrs2p in the yeast inner mitochondrial membrane. Although several CorA crystal structures are available, the molecular mechanism of Mg2+ uptake remains to be established. Here we use electron paramagnetic resonance spectroscopy, electrophysiology and molecular dynamic simulations to show that CorA is regulated by cytoplasmic Mg2+ acting as a ligand and elucidate the basic conformational rearrangements responsible for Mg2+-dependent gating. Mg2+ unbinding at the divalent cation sensor triggers a conformational change that leads to the inward motion of the stalk helix, which propagates to the pore-forming transmembrane helix TM1. Helical tilting and rotation in TM1 generates an iris-like motion that increases the diameter of the permeation pathway, triggering ion conduction. This work establishes the molecular basis of a Mg2+-driven negative feedback loop in CorA as the key physiological event controlling Mg2+ uptake and homeostasis in prokaryotes.

Baryon spectroscopy and the omega minus

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

Samios, N.P.

1994-12-31

In this report, I will mainly discuss baryon resonances with emphasis on the discovery of the {Omega}{sup {minus}}. However, for completeness, I will also present some data on the meson resonances which together with the baryons led to the uncovering of the SU(3) symmetry of particles and ultimately to the concept of quarks.

Thermal behavior of epoxidized cardanol diethyl phosphate as novel renewable plasticizer for poly(vinyl chloride)

USDA-ARS?s Scientific Manuscript database

A novel plasticizer, epoxidized cardanol diethyl phosphate (ECEP), based on cardanol was synthesized. Chemical structure of ECEP was characterized by fourier transform infrared (FTIR), 1H-nuclear magnetic resonance(1H NMR) and 13C-nuclear magnetic resonance(13C NMR) spectroscopy. Effects of ECEP sub...

Surface Plasmon Resonance: An Introduction to a Surface Spectroscopy Technique

ERIC Educational Resources Information Center

Tang, Yijun; Zeng, Xiangqun; Liang, Jennifer

2010-01-01

Surface plasmon resonance (SPR) has become an important optical biosensing technology in the areas of biochemistry, biology, and medical sciences because of its real-time, label-free, and noninvasive nature. The high cost of commercial devices and consumables has prevented SPR from being introduced in the undergraduate laboratory. Here, we present…

Analysis of cocondensation of melamine and urea through carbon 13 enriched formaldehyde with C-13 nuclear magnetic resonance spectroscopy

Treesearch

Bunichiro Tomita; Chung-Yun Hse

1995-01-01

The urea-formaldehyde (UF) resins, melamine-formaldehyde (MF) resins, and melamine-ureaformaldehyde (MUF) cocondensed resins were synthesized using the labeling method with 13C enriched formaldehyde under neutral conditions and their 13C-NMR (nuclear magnetic resonance) spectra were analyzed. The remarkable down-field...

Measurement of Rate Constants for Homodimer Subunit Exchange Using Double Electron-Electron Resonance and Paramagnetic Relaxation Enhancements

PubMed Central

Yang, Yunhuang; Ramelot, Theresa A.; Ni, Shuisong; McCarrick, Robert M.; Kennedy, Michael A.

2013-01-01

Here, we report novel methods to measure rate constants for homodimer subunit exchange using double electron-electron resonance (DEER) electron paramagnetic resonance spectroscopy measurements and nuclear magnetic resonance spectroscopy based paramagnetic relaxation enhancement (PRE) measurements. The techniques were demonstrated using the homodimeric protein Dsy0195 from the strictly anaerobic bacterium Desulfitobacterium hafniense Y51. At specific times following mixing site-specific MTSL-labeled Dsy0195 with uniformly 15N-labeled Dsy0195, the extent of exchange was determined either by monitoring the decrease of MTSL-labeled homodimer from the decay of the DEER modulation depth or by quantifying the increase of MTSL-labeled/15N-labeled heterodimer using PREs. Repeated measurements at several time points following mixing enabled determination of the homodimer subunit dissociation rate constant, k−1;, which was 0.037 ± 0.005 min−1 derived from DEER experiments with a corresponding half-life time of 18.7 minutes. These numbers agreed with independent measurements obtained from PRE experiments. These methods can be broadly applied to protein-protein and protein-DNA complex studies. PMID:23180051

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.

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.

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.

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.

The effect of structural disorder on guided resonances in photonic crystal slabs studied with terahertz time-domain spectroscopy.

PubMed

Prasad, Tushar; Colvin, Vicki L; Mittleman, Daniel M

2007-12-10

We measure the normal-incidence transmission coefficient of photonic crystal slabs with hexagonal arrays of air holes in silicon. The transmission spectra exhibit sharp resonant features with Fano line shapes. They are produced due to the coupling of the leaky photonic crystal modes, called guided resonances, to the continuum of free-space modes. We investigate the effects of several types of structural disorder on the spectra of these resonances. Our results indicate that guided resonances are very tolerant to disorder in the hole diameter and to interface roughness, but very sensitive to disorder in the lattice periodicity.

Nucleophilic Substitution Reactions Using Phosphine Nucleophiles: An Introduction to Phosphorus-31 NMR

ERIC Educational Resources Information Center

Sibbald, Paul A.

2015-01-01

Nuclear magnetic resonance (NMR) spectroscopy is commonly used in modern synthetic chemistry to monitor the conversion of reactants to products. Since instruction in the use of NMR spectroscopy typically does not occur until after the introduction of nucleophilic substitution reactions, organic chemistry students are not able to take advantage of…

Electromagnetically-induced-transparency intensity-correlation power broadening in a buffer gas

NASA Astrophysics Data System (ADS)

Zheng, Aojie; Green, Alaina; Crescimanno, Michael; O'Leary, Shannon

2016-04-01

Electromagnetically-induced-transparency (EIT) noise correlation spectroscopy holds promise as a simple, robust method for performing high-resolution spectroscopy used in optical magnetometry and clocks. Of relevance to these applications, we report on the role of buffer gas pressure and magnetic field gradients on power broadening of Zeeman-EIT noise correlation resonances.

Synthesis and characterization of a new Inonotus obliquus polysaccharide-iron(III) complex.

PubMed

Wang, Jia; Chen, Haixia; Wang, Yanwei; Xing, Lisha

2015-04-01

A new Inonotus obliquus polysaccharide-iron(III) complex (IOPS-iron) was synthesized and characterized. The preparation conditions of IOPS-iron(III) were optimized and the physicochemical properties were characterized by physicochemical methods, scanning electron microscopy (SEM), electron paramagnetic resonance (EPR) spectroscopy, fourier transform infrared (FTIR) spectroscopy, circular dichroism (CD) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy, respectively. The highest iron content of IOPS-iron(III) complex (19.40%) was obtained at the conditions: the ratio of IOPS and FeCl3 • 6H2O was 3:5 (w/w), the pH value of alkali solution was 10, the reaction temperature was 30 °C and the reaction time was 6h. The iron(III) was shown to be bound through the binding sites of the polysaccharide IOPS and it could form spatially separated iron centers on the polysaccharide backbone. IOPS-iron(III) complex was found to have good digestive availability and antioxidant activities in the in vitro assays, which suggested the IOPS-iron(III) complex might be used as a new iron supplement candidate. Copyright © 2015 Elsevier B.V. All rights reserved.

MR imaging, proton MR spectroscopy, ultrasonographic, histologic findings in patients with chronic lymphedema.

PubMed

Fumiere, E; Leduc, O; Fourcade, S; Becker, C; Garbar, C; Demeure, R; Wilputte, F; Leduc, A; Delcour, C

2007-12-01

Lymphedema is a progressive disease with multiple alterations occurring in the dermis. We undertook this study using high-frequency ultrasonography (US), magnetic resonance imaging, proton MR spectroscopy and histology to examine structural changes occurring in the subcutaneous tissue and precisely describe the nature of intralobular changes in chronic lymphedema. Four cutaneous and subcutaneous tissue biopsies from patients with chronic lymphedema during lymphonodal transplantation were studied. We performed US with a 13.5 MHz transducer, TSE T1 and TSE T2 magnetic resonance images with and without fat-suppression, MR Chemical Shift Imaging Spectroscopy and histological evaluation on these biopsies. We found that normal subcutaneous septa are seen as hyperechogenic lines in US and hyposignal lines in MRI and that hyperechogenic subcutis in US can be due to interlobular and intralobular water accumulation and/or to interlobular and intralobular fibrosis. Our study also confirms the usefulness of MR spectroscopy to assess water or fat content of soft tissue. Thus, multiple imaging modalities may be necessary to precisely delineate the nature of tissue alterations in chronic lymphedema.

Electronic structure of ferromagnetic heavy fermion, YbPdSi, YbPdGe, and YbPtGe studied by photoelectron spectroscopy, x-ray emission spectroscopy, and DFT + DMFT calculations

DOE PAGES

Yamaoka, Hitoshi; Thunstrom, Patrik; Tsujii, Naohito; ...

2017-11-02

Here, the electronic structures of ferromagnetic heavy fermion Yb compounds of YbPdSi, YbPdGe, and YbPtGe are studied by photoelectron spectroscopy around the Yb 4d–4f resonance, resonant x-ray emission spectroscopy at the Yb L 3 absorption edge, and density functional theory combined with dynamical mean field theory calculations. These compounds all have a temperature-independent intermediate Yb valence with largemore » $${\\rm Yb}^{3+}$$ and small $${\\rm Yb}^{2+}$$ components. The magnitude of the Yb valence is evaluated to be YbPtGe $<$ YbPdGe $$\\lesssim $$ YbPdSi, suggesting that YbPtGe is the closest to the quantum critical point among the three Yb compounds. Our results support the scenario of the coexistence of heavy fermion behavior and ferromagnetic ordering which is described by a magnetically-ordered Kondo lattice where the magnitude of the Kondo effect and the RKKY interaction are comparable.« less

1,1-dimethylhydrazine as a high purity nitrogen source for MOVPE-water reduction and quantification using nuclear magnetic resonance, gas chromatography-atomic emission detection spectroscopy and cryogenic-mass spectroscopy analytical techniques

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

Odedra, R.; Smith, L.M.; Rushworth, S.A.

2000-01-01

Hydrazine derivatives are attractive low temperature nitrogen sources for use in MOVPE due to their low thermal stability. However their purification and subsequent analysis has not previously been investigated in depth for this application. A detailed study on 1,1-dimethylhydrazine {l{underscore}brace}(CH{sub 3}){sub 2}N-NH{sub 2}{r{underscore}brace} purified by eight different methods and the subsequent quantitative measurements of water present in the samples obtained is reported here. A correlation between {sup 1}H nuclear magnetic resonance spectroscopy (NMR), gas chromatography-atomic emission detection (GC-AED) and cryogenic mass spectroscopy (Cryogenic-MS) has been performed. All three analysis techniques can be used to measure water in the samples andmore » with the best purification the water content can be lowered well below 100 ppm. The high purity of this material has been demonstrated by growth results and the state-of-the-art performance of laser diodes.« less

Coupled aging effects in nanofiber-reinforced siloxane foams

DOE PAGES

Labouriau, Andrea; Robison, Tom; Geller, Drew Adam; ...

2018-01-11

Here, this study investigates the combined effects of ionizing radiation and thermal treatments on the aging of siloxane foams containing small amounts of carbon nanofibers. Our siloxane foams were exposed to accelerated aging conditions for more than two years, resulting in very low dose rates. In addition, foams were aged under compressive load to evaluate the strength of the porous microstructure. Samples were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), Mössbauer, mass spectroscopy, electron paramagnetic resonance spectroscopy (EPR), solvent swelling, imaging techniques, uniaxial compressive load testing and tearmore » testing. No significant changes in thermal stability or chemistry of the accelerated aged foam were observed, although gas evolution was detected. Changes in crystallization levels at low temperatures, microstructure, and mechanical properties were observed for foams with and without carbon nanofibers. In particular, foams aged under compressive load showed irreversible deformation of the porous microstructure. This study demonstrates that aging effects were enhanced when thermal and radiolysis were coupled together and that the addition of carbon nanofibers did not improve aging effects.« less

Electronic structure of ferromagnetic heavy fermion, YbPdSi, YbPdGe, and YbPtGe studied by photoelectron spectroscopy, x-ray emission spectroscopy, and DFT + DMFT calculations

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

Yamaoka, Hitoshi; Thunstrom, Patrik; Tsujii, Naohito

Here, the electronic structures of ferromagnetic heavy fermion Yb compounds of YbPdSi, YbPdGe, and YbPtGe are studied by photoelectron spectroscopy around the Yb 4d–4f resonance, resonant x-ray emission spectroscopy at the Yb L 3 absorption edge, and density functional theory combined with dynamical mean field theory calculations. These compounds all have a temperature-independent intermediate Yb valence with largemore » $${\\rm Yb}^{3+}$$ and small $${\\rm Yb}^{2+}$$ components. The magnitude of the Yb valence is evaluated to be YbPtGe $<$ YbPdGe $$\\lesssim $$ YbPdSi, suggesting that YbPtGe is the closest to the quantum critical point among the three Yb compounds. Our results support the scenario of the coexistence of heavy fermion behavior and ferromagnetic ordering which is described by a magnetically-ordered Kondo lattice where the magnitude of the Kondo effect and the RKKY interaction are comparable.« less

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

Methyl 3-[3',4'-(methylenedioxy)phenyl]-2-methyl glycidate: an ecstasy precursor seized in Sydney, Australia.

PubMed

Collins, Michael; Heagney, Aaron; Cordaro, Frank; Odgers, David; Tarrant, Gregory; Stewart, Samantha

2007-07-01

Five 44 gallon drums labeled as glycidyl methacrylate were seized by the Australian Customs Service and the Australian Federal Police at Port Botany, Sydney, Australia, in December 2004. Each drum contained a white, semisolid substance that was initially suspected to be 3,4-methylenedioxymethylamphetamine (MDMA). Gas chromatography-mass spectroscopy (GC/MS) analysis demonstrated that the material was neither glycidyl methacrylate nor MDMA. Because intelligence sources employed by federal agents indicated that this material was in some way connected to MDMA production, suspicion fell on the various MDMA precursor chemicals. Using a number of techniques including proton nuclear magnetic resonance spectroscopy ((1)H NMR), carbon nuclear magnetic resonance spectroscopy ((13)C NMR), GC/MS, infrared spectroscopy, and total synthesis, the unknown substance was eventually identified as methyl 3-[3',4'(methylenedioxy)phenyl]-2-methyl glycidate. The substance was also subjected to a published hydrolysis and decarboxylation procedure and gave a high yield of the MDMA precursor chemical, 3,4-methylenedioxyphenyl-2-propanone, thereby establishing this material as a "precursor to a precursor."

Coupled aging effects in nanofiber-reinforced siloxane foams

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

Labouriau, Andrea; Robison, Tom; Geller, Drew Adam

Here, this study investigates the combined effects of ionizing radiation and thermal treatments on the aging of siloxane foams containing small amounts of carbon nanofibers. Our siloxane foams were exposed to accelerated aging conditions for more than two years, resulting in very low dose rates. In addition, foams were aged under compressive load to evaluate the strength of the porous microstructure. Samples were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), Mössbauer, mass spectroscopy, electron paramagnetic resonance spectroscopy (EPR), solvent swelling, imaging techniques, uniaxial compressive load testing and tearmore » testing. No significant changes in thermal stability or chemistry of the accelerated aged foam were observed, although gas evolution was detected. Changes in crystallization levels at low temperatures, microstructure, and mechanical properties were observed for foams with and without carbon nanofibers. In particular, foams aged under compressive load showed irreversible deformation of the porous microstructure. This study demonstrates that aging effects were enhanced when thermal and radiolysis were coupled together and that the addition of carbon nanofibers did not improve aging effects.« less

Iron- and 4-hydroxy-2-alkylquinoline-containing periplasmic inclusion bodies of Pseudomonas aeruginosa: A chemical analysis

USGS Publications Warehouse

Royt, P.W.; Honeychuck, R.V.; Pant, R.R.; Rogers, M.L.; Asher, L.V.; Lloyd, J.R.; Carlos, W.E.; Belkin, H.E.; Patwardhan, S.

2007-01-01

Dark aggregated particles were seen on pellets of iron-rich, mid-logarithmic phase Pseudomonas aeruginosa. Transmission electron microscopy of these cells showed inclusion bodies in periplasmic vacuoles. Aggregated particles isolated from the spent medium of these cells contained iron as indicated by atomic absorption spectroscopy and by electron paramagnetic resonance spectroscopy that revealed Fe3+. Scanning electron microscopy/energy dispersive X-ray analysis of whole cells revealed the presence of iron-containing particles beneath the surface of the cell, indicating that the isolated aggregates were the intracellular inclusion bodies. Collectively, mass spectroscopy and nuclear magnetic resonance spectroscopy of the isolated inclusion bodies revealed the presence of 3,4-dihydroxy-2-heptylquinoline which is the Pseudomonas quinolone signaling compound (PQS) and an iron chelator; 4-hydroxy-2-heptylquinoline (pseudan VII), which is an iron chelator, antibacterial compound and precursor of PQS; 4-hydroxy-2-nonylquinoline (pseudan IX) which is an iron chelator and antibacterial compound; 4-hydroxy-2-methylquinoline (pseudan I), and 4-hydroxy-2-nonylquinoline N-oxide. ?? 2006 Elsevier Inc. All rights reserved.

Characterization of Colloidal Quantum Dot Ligand Exchange by X-ray Photoelectron Spectroscopy

NASA Astrophysics Data System (ADS)

Atewologun, Ayomide; Ge, Wangyao; Stiff-Roberts, Adrienne D.

2013-05-01

Colloidal quantum dots (CQDs) are chemically synthesized semiconductor nanoparticles with size-dependent wavelength tunability. Chemical synthesis of CQDs involves the attachment of long organic surface ligands to prevent aggregation; however, these ligands also impede charge transport. Therefore, it is beneficial to exchange longer surface ligands for shorter ones for optoelectronic devices. Typical characterization techniques used to analyze surface ligand exchange include Fourier-transform infrared spectroscopy, x-ray diffraction, transmission electron microscopy, and nuclear magnetic resonance spectroscopy, yet these techniques do not provide a simultaneously direct, quantitative, and sensitive method for evaluating surface ligands on CQDs. In contrast, x-ray photoelectron spectroscopy (XPS) can provide nanoscale sensitivity for quantitative analysis of CQD surface ligand exchange. A unique aspect of this work is that a fingerprint is identified for shorter surface ligands by resolving the regional XPS spectrum corresponding to different types of carbon bonds. In addition, a deposition technique known as resonant infrared matrix-assisted pulsed laser evaporation is used to improve the CQD film uniformity such that stronger XPS signals are obtained, enabling more accurate analysis of the ligand exchange process.

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.

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.

Modeling of Plutonium Ionization Probabilities for Use in Nuclear Forensic Analysis by Resonance Ionization Mass Spectrometry

DTIC Science & Technology

2016-12-01

masses collide, they form a supercritical mass . Criticality refers to the neutron population within the system. A critical system is one that can...Spectrometry, no. 242, pp. 161–168, 2005. [9] S. Raeder, “Trace analysis of actinides in the environment by means of resonance ionization mass ...first ionization potential of actinide elements by resonance ionization mass spectrometry.” Spectrochimica Acta part B: Atomic Spectroscopy. vol. 52

Laser generation in microdisc resonators with InAs/GaAs quantum dots transferred on a silicon substrate

NASA Astrophysics Data System (ADS)

Nadtochiy, A. M.; Kryzhanovskaya, N. V.; Maximov, M. V.; Zhukov, A. E.; Moiseev, E. I.; Kulagina, M. M.; Vashanova, K. A.; Zadiranov, Yu. M.; Mukhin, I. S.; Arakcheeva, E. M.; Livshits, D.; Lipovskii, A. A.

2013-09-01

Microdisc resonators based on InAs/GaAs quantum dots separated from a GaAs substrate by selective etching and fixed to a silicon substrate by epoxy glue are studied using luminescence spectroscopy. A disc resonator 6 μm in diameter exhibits quasi-single-mode laser generation at a temperature of 78 K with a threshold power of 320 μW and λ/Δλ ˜ 27000.

High-resolution study of the prominent near-threshold resonances in the Ar 3s-electron photoionization

NASA Astrophysics Data System (ADS)

Lauer, S.; Liebel, H.; Vollweiler, F.; Schmoranzer, H.; Reichardt, G.; Wilhelmi, O.; Mentzel, G.; Schartner, K.-H.; Sukhorukov, V. L.; Lagutin, B. M.; Petrov, I. D.; Demekhin, Ph. V.

1998-10-01

The absolute Ar 3s-electron photoionization cross section was measured in the exciting-photon energy range from 30.65 to 31.75 eV by photon-induced fluorescence spectroscopy (PIFS). The bandwidth of the exciting synchrotron radiation was 4.8 meV. The profiles of the resonances observed in the Ar 3s-electron photoionization were compared with the profiles of the resonances in the total photoabsorption.

Probing plasmon resonances of individual aluminum nanoparticles

NASA Astrophysics Data System (ADS)

Wei, Zhongxia; Mao, Peng; Cao, Lu; Song, Fengqi

2018-01-01

The plasmon resonances of individual aluminum nanoparticles are investigated by electron energy-loss spectroscopy (EELS) in scanning transmission electron microscope (STEM). Surface plasmon mode and bulk plasmon mode of Al nanoparticles are clearly characterized in the EEL spectra. Discrete dipole approximation (DDA) calculations show that as the particle diameter increases from 20 nm to 100 nm, the plasmon resonance shifts to lower energy and higher mode of surface plasmon arises when the diameter reaches 60 nm and larger.

Laser Spectroscopy Investigations of Materials for Solid State Laser Systems.

DTIC Science & Technology

1988-02-01

34 ing tools such as electron paramagnetic resonance and ". oc Be11 uniaxial stress. 19 However, the lattice structure of chryso- .,Pt AI3 PAIR 4 beryl... paramagnetic of these new emission bands is not known at the present time. resonance spectrum. 15The other features of the optical spectra cannot be...solution is peak absorption c-iefficient, and E, is the saturation field. The detuning parameter which accounts for the width of the resonant electronic

Characterization of Strong Light-Matter Coupling in Semiconductor Quantum-Dot Microcavities via Photon-Statistics Spectroscopy

NASA Astrophysics Data System (ADS)

Schneebeli, L.; Kira, M.; Koch, S. W.

2008-08-01

It is shown that spectrally resolved photon-statistics measurements of the resonance fluorescence from realistic semiconductor quantum-dot systems allow for high contrast identification of the two-photon strong-coupling states. Using a microscopic theory, the second-rung resonance of Jaynes-Cummings ladder is analyzed and optimum excitation conditions are determined. The computed photon-statistics spectrum displays gigantic, experimentally robust resonances at the energetic positions of the second-rung emission.

Identification of B. anthracis N(5)-carboxyaminoimidazole ribonucleotide mutase (PurE) active site binding compounds via fragment library screening.

PubMed

Lei, Hao; Jones, Christopher; Zhu, Tian; Patel, Kavankumar; Wolf, Nina M; Fung, Leslie W-M; Lee, Hyun; Johnson, Michael E

2016-02-15

The de novo purine biosynthesis pathway is an attractive target for antibacterial drug design, and PurE from this pathway has been identified to be crucial for Bacillus anthracis survival in serum. In this study we adopted a fragment-based hit discovery approach, using three screening methods-saturation transfer difference nucleus magnetic resonance (STD-NMR), water-ligand observed via gradient spectroscopy (WaterLOGSY) NMR, and surface plasmon resonance (SPR), against B. anthracis PurE (BaPurE) to identify active site binding fragments by initially testing 352 compounds in a Zenobia fragment library. Competition STD NMR with the BaPurE product effectively eliminated non-active site binding hits from the primary hits, selecting active site binders only. Binding affinities (dissociation constant, KD) of these compounds varied between 234 and 301μM. Based on test results from the Zenobia compounds, we subsequently developed and applied a streamlined fragment screening strategy to screen a much larger library consisting of 3000 computationally pre-selected fragments. Thirteen final fragment hits were confirmed to exhibit binding affinities varying from 14μM to 700μM, which were categorized into five different basic scaffolds. All thirteen fragment hits have ligand efficiencies higher than 0.30. We demonstrated that at least two fragments from two different scaffolds exhibit inhibitory activity against the BaPurE enzyme. Published by Elsevier Ltd.

Advances in basic science methodologies for clinical diagnosis in female stress urinary incontinence.

PubMed

Abdulaziz, Marwa; Deegan, Emily G; Kavanagh, Alex; Stothers, Lynn; Pugash, Denise; Macnab, Andrew

2017-06-01

We provide an overview of advanced imaging techniques currently being explored to gain greater understanding of the complexity of stress urinary incontinence (SUI) through better definition of structural anatomic data. Two methods of imaging and analysis are detailed for SUI with or without prolapse: 1) open magnetic resonance imaging (MRI) with or without the use of reference lines; and 2) 3D reconstruction of the pelvis using MRI. An additional innovative method of assessment includes the use of near infrared spectroscopy (NIRS), which uses non-invasive photonics in a vaginal speculum to objectively evaluate pelvic floor muscle (PFM) function as it relates to SUI pathology. Advantages and disadvantages of these techniques are described. The recent innovation of open-configuration magnetic resonance imaging (MRO) allows images to be captured in sitting and standing positions, which better simulates states that correlate with urinary leakage and can be further enhanced with 3D reconstruction. By detecting direct changes in oxygenated muscle tissue, the NIRS vaginal speculum is able to provide insight into how the oxidative capacity of the PFM influences SUI. The small number of units able to provide patient evaluation using these techniques and their cost and relative complexity are major considerations, but if such imaging can optimize diagnosis, treatment allocation, and selection for surgery enhanced imaging techniques may prove to be a worthwhile and cost-effective strategy for assessing and treating SUI.

Synthesis of oxocarbon-encapsulated gold nanoparticles with blue-shifted localized surface plasmon resonance by pulsed laser ablation in water with CO2 absorbers

NASA Astrophysics Data System (ADS)

Del Rosso, T.; Rey, N. A.; Rosado, T.; Landi, S.; Larrude, D. G.; Romani, E. C.; Freire Junior, F. L.; Quinteiro, S. M.; Cremona, M.; Aucelio, R. Q.; Margheri, G.; Pandoli, O.

2016-06-01

Colloidal suspensions of oxocarbon-encapsulated gold nanoparticles have been synthesized in a one-step procedure by pulsed-laser ablation (PLA) at 532 nm of a solid gold target placed in aqueous solution containing CO2 absorbers, but without any stabilizing agent. Multi-wavelength surface enhanced Raman spectroscopy allows the identification of adsorbed amorphous carbon and graphite, Au-carbonyl, Au coordinated CO2-derived bicarbonates/carbonates and hydroxyl groups around the AuNPs core. Scanning electron microscopy, energy dispersive x-ray analysis and high resolution transmission electron microscopy highlight the organic shell structure around the crystalline metal core. The stability of the colloidal solution of nanocomposites (NCs) seems to be driven by solvation forces and is achieved only in neutral or basic pH using monovalent hydroxide counter-ions (NaOH, KOH). The NCs are characterized by a blue shift of the localized surface plasmon resonance (LSPR) band typical of metal-ligand stabilization by terminal π-back bonding, attributed to a core charging effect caused by Au-carbonyls. Total organic carbon measurements detect the final content of organic carbon in the colloidal solution of NCs that is about six times higher than the value of the water solution used to perform PLA. The colloidal dispersions of NCs are stable for months and are applied as analytical probes in amino glycoside antibiotic LSPR based sensing.

Synthesis of oxocarbon-encapsulated gold nanoparticles with blue-shifted localized surface plasmon resonance by pulsed laser ablation in water with CO2 absorbers.

PubMed

Del Rosso, T; Rey, N A; Rosado, T; Landi, S; Larrude, D G; Romani, E C; Junior, F L Freire; Quinteiro, S M; Cremona, M; Aucelio, R Q; Margheri, G; Pandoli, O

2016-06-24

Colloidal suspensions of oxocarbon-encapsulated gold nanoparticles have been synthesized in a one-step procedure by pulsed-laser ablation (PLA) at 532 nm of a solid gold target placed in aqueous solution containing CO2 absorbers, but without any stabilizing agent. Multi-wavelength surface enhanced Raman spectroscopy allows the identification of adsorbed amorphous carbon and graphite, Au-carbonyl, Au coordinated CO2-derived bicarbonates/carbonates and hydroxyl groups around the AuNPs core. Scanning electron microscopy, energy dispersive x-ray analysis and high resolution transmission electron microscopy highlight the organic shell structure around the crystalline metal core. The stability of the colloidal solution of nanocomposites (NCs) seems to be driven by solvation forces and is achieved only in neutral or basic pH using monovalent hydroxide counter-ions (NaOH, KOH). The NCs are characterized by a blue shift of the localized surface plasmon resonance (LSPR) band typical of metal-ligand stabilization by terminal π-back bonding, attributed to a core charging effect caused by Au-carbonyls. Total organic carbon measurements detect the final content of organic carbon in the colloidal solution of NCs that is about six times higher than the value of the water solution used to perform PLA. The colloidal dispersions of NCs are stable for months and are applied as analytical probes in amino glycoside antibiotic LSPR based sensing.

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.

Continuous-wave deep ultraviolet sources for resonance Raman explosive sensing

NASA Astrophysics Data System (ADS)

Yellampalle, Balakishore; Martin, Robert; Sluch, Mikhail; McCormick, William; Ice, Robert; Lemoff, Brian

2015-05-01

A promising approach to stand-off detection of explosive traces is using resonance Raman spectroscopy with Deepultraviolet (DUV) light. The DUV region offers two main advantages: strong explosive signatures due to resonant and λ- 4 enhancement of Raman cross-section, and lack of fluorescence and solar background. For DUV Raman spectroscopy, continuous-wave (CW) or quasi-CW lasers are preferable to high peak powered pulsed lasers because Raman saturation phenomena and sample damage can be avoided. In this work we present a very compact DUV source that produces greater than 1 mw of CW optical power. The source has high optical-to-optical conversion efficiency, greater than 5 %, as it is based on second harmonic generation (SHG) of a blue/green laser source using a nonlinear crystal placed in an external resonant enhancement cavity. The laser system is extremely compact, lightweight, and can be battery powered. Using two such sources, one each at 236.5 nm and 257.5 nm, we are building a second generation explosive detection system called Dual-Excitation-Wavelength Resonance-Raman Detector (DEWRRED-II). The DEWRRED-II system also includes a compact dual-band high throughput DUV spectrometer, and a highly-sensitive detection algorithm. The DEWRRED technique exploits the DUV excitation wavelength dependence of Raman signal strength, arising from complex interplay of resonant enhancement, self-absorption and laser penetration depth. We show sensor measurements from explosives/precursor materials at different standoff distances.

Conformational Specific Infrared and Ultraviolet Spectroscopy of Cold YA(D-Pro)AA\\cdotH+ Ions: a Sterochemical "twist" on the Proline Effect

NASA Astrophysics Data System (ADS)

Harrilal, Christopher P.; DeBlase, Andrew F.; Burke, Nicole L.; McLuckey, Scott A.; Zwier, Timothy S.

2016-06-01

The "proline effect" is a well-known fragmentation phenomenon in mass spectrometry, in which y-fragments are produced preferentially over b-fragments during the collision induced dissociation of protonated L-proline containing peptide ions. This specific fragmentation channel is favored because of the high basicity of the secondary amine intermediate and the ring instability in alternative bn+ products [ASMS 2014, 25, 1705]. In contrast, peptides containing the D-Pro stereoisomer have been shown to largely favor the production of b4+ ions over y3+ ions. This strongly suggests that differences in the conformational preferences between the D-Pro and L-Pro diastereomers are likely to be responsible but structural evidence has been lacking to date. Using tandem mass spectrometry and IR-UV double resonant action spectroscopy we are able to compare the 3D structures of cold [YA(D-Pro)AA+H]+ to [YA(L-Pro)AA+H]+ ions. The UV action spectra reveals two major conformers in [YA(D-Pro)AA+H]+ and one major conformer in [YA(L-Pro)AA+H]+. Clear differences in the hydrogen bonding patterns are apparent between the two conformers observed in the D-Pro specie which are both distinct from the L-Pro diastereomer. Furthermore, conformer and diastereomer specific photofragmentation patterns are observed. It is also noted that a ten-fold photofragment enhancement unique to one of the D-Pro conformers is observed upon absorption of a resonant IR photon after UV excitation. Differences in the excited state photophysics between the two D-Pro conformers suggest that vibrational excitation of S1 turns on coupling to the dissociative -Tyr channel in one conformer, while this coupling is already present in the vibronic ground state of the other. Calculated harmonic spectra (M052X/6-31+G*) of conformers obtained from Monte Carlo searches to the experimental spectra.

Leukoencephalopathy with thalamus and brainstem involvement and high lactate 'LTBL' caused by EARS2 mutations.

PubMed

Steenweg, Marjan E; Ghezzi, Daniele; Haack, Tobias; Abbink, Truus E M; Martinelli, Diego; van Berkel, Carola G M; Bley, Annette; Diogo, Luisa; Grillo, Eugenio; Te Water Naudé, Johann; Strom, Tim M; Bertini, Enrico; Prokisch, Holger; van der Knaap, Marjo S; Zeviani, Massimo

2012-05-01

In the large group of genetically undetermined infantile-onset mitochondrial encephalopathies, multiple defects of mitochondrial DNA-related respiratory-chain complexes constitute a frequent biochemical signature. In order to identify responsible genes, we used exome-next-generation sequencing in a selected cohort of patients with this biochemical signature. In an isolated patient, we found two mutant alleles for EARS2, the gene encoding mitochondrial glutamyl-tRNA synthetase. The brain magnetic resonance imaging of this patient was hallmarked by extensive symmetrical cerebral white matter abnormalities sparing the periventricular rim and symmetrical signal abnormalities of the thalami, midbrain, pons, medulla oblongata and cerebellar white matter. Proton magnetic resonance spectroscopy showed increased lactate. We matched this magnetic resonance imaging pattern with that of a cohort of 11 previously selected unrelated cases. We found mutations in the EARS2 gene in all. Subsequent detailed clinical and magnetic resonance imaging based phenotyping revealed two distinct groups: mild and severe. All 12 patients shared an infantile onset and rapidly progressive disease with severe magnetic resonance imaging abnormalities and increased lactate in body fluids and proton magnetic resonance spectroscopy. Patients in the 'mild' group partially recovered and regained milestones in the following years with striking magnetic resonance imaging improvement and declining lactate levels, whereas those of the 'severe' group were characterized by clinical stagnation, brain atrophy on magnetic resonance imaging and persistent lactate increases. This new neurological disease, early-onset leukoencephalopathy with thalamus and brainstem involvement and high lactate, is hallmarked by unique magnetic resonance imaging features, defined by a peculiar biphasic clinical course and caused by mutations in a single gene, EARS2, expanding the list of medically relevant defects of mitochondrial DNA translation.

Recent Progress in Silicon Mems Oscillators

DTIC Science & Technology

2008-12-01

MEMS oscillator. As shown, a MEMS resonator is connected to an IC. The reference oscillator, which is basically a transimpedance amplifier ...small size), and (3) DC bias voltage required to operate the resonators. As a result, instead of Colpitts or Pierce architecture, a transimpedence ... amplifier is typically used for sustain the oscillation. The frequency of the resonators is determined by both material properties and geometry of

Structural Characterization of the Putative Cholinergic Binding Region alpha(179-201) of the Nicotinic Acetylcholine Receptor. Part 1. Review and Experimental Design.

DTIC Science & Technology

1993-04-01

SUBJCT TERMS .. 15. NUMBER OF PAGES Nicotinic acetylcholine receptor FTIR 21 Vibrational spectroscopy Cholinergic 16. PRICE COOE Resonance raman 17...Wilson et al 1955). FMR spectroscopy measures the absorbance of infra-red rad iation, where as Raman spectroscopy measures inelastic scattering of...frequency is domrunated by that chromophore, then Raman scattering involving vibrations localized in that chromophore will be sharply enhanced(Cantor and

Vascular Functional Imaging and Physiological Environment of Hyperplasia, Non-Metastatic and Metastatic Breast Cancer

DTIC Science & Technology

1997-10-01

Specific Aim 1). The overall goal of this research proposal is to use noninvasive Magnetic Resonance (MR) Imaging (I) and Spectroscopy (S) to answer the... spectroscopy in establishing the role of nm23 genes in tumor metabolism and metastatic dissemination. INTRODUCTION Despite continuing advances in the...cellular mechanisms by which the nm23 protein suppresses metastatic phenotypic expression is as yet unknown. Here we have used 3 1P NMR spectroscopy to

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).

Nuclear magnetic resonance studies of quadrupolar nuclei and dipolar field effects

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

Urban, Jeffry Todd

Experimental and theoretical research conducted in two areas in the field of nuclear magnetic resonance (NMR) spectroscopy is presented: (1) studies of the coherent quantum-mechanical control of the angular momentum dynamics of quadrupolar (spin I > 1/2) nuclei and its application to the determination of molecular structure; and (2) applications of the long-range nuclear dipolar field to novel NMR detection methodologies.The dissertation is organized into six chapters. The first two chapters and associated appendices are intended to be pedagogical and include an introduction to the quantum mechanical theory of pulsed NMR spectroscopy and the time dependent theory of quantum mechanics.more » The third chapter describes investigations of the solid-state multiple-quantum magic angle spinning (MQMAS) NMR experiment applied to I = 5/2 quadrupolar nuclei. This work reports the use of rotary resonance-matched radiofrequency irradiation for sensitivity enhancement of the I = 5/2 MQMAS experiment. These experiments exhibited certain selective line narrowing effects which were investigated theoretically.The fourth chapter extends the discussion of multiple quantum spectroscopy of quadrupolar nuclei to a mostly theoretical study of the feasibility of enhancing the resolution of nitrogen-14 NMR of large biomolecules in solution via double-quantum spectroscopy. The fifth chapter continues to extend the principles of multiple quantum NMR spectroscopy of quadrupolar nuclei to make analogies between experiments in NMR/nuclear quadrupolar resonance (NQR) and experiments in atomic/molecular optics (AMO). These analogies are made through the Hamiltonian and density operator formalism of angular momentum dynamics in the presence of electric and magnetic fields.The sixth chapter investigates the use of the macroscopic nuclear dipolar field to encode the NMR spectrum of an analyte nucleus indirectly in the magnetization of a sensor nucleus. This technique could potentially serve as an encoding module for the recently developed NMR remote detection experiment. The feasibility of using hyperpolarized xenon-129 gas as a sensor is discussed. This work also reports the use of an optical atomic magnetometer to detect the nuclear magnetization of Xe-129 gas, which has potential applicability as a detection module for NMR remote detection experiments.« less

Undergraduate Electron-Spin-Resonance Experiment.

ERIC Educational Resources Information Center

Willis, James S.

1980-01-01

Describes the basic procedures for use of an electron-spin resonance spectrometer and potassium azide (KN3) in an experiment which extends from the phase of sample preparation (crystal growth, sample mounting, and orientation) through data taking to the stages of calculation and theoretical explanation. (Author/DS)

Mechanical Resonance of a Plastic Strip.

ERIC Educational Resources Information Center

Ayers, R. Dean

1981-01-01

Presents an experiment to illustrate mechanical resonance designed for use in lower division laboratories. The apparatus and procedure have been kept simple. The basic experiment yields measurements of amplitude versus driving frequency, but a fairly simple elaboration allows for measurements of phase lag as well. (Author/SK)

Magnetic resonance microscopy of prostate tissue: How basic science can inform clinical imaging development

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

Bourne, Roger

2013-03-15

This commentary outlines how magnetic resonance imaging (MRI) microscopy studies of prostate tissue samples and whole organs have shed light on a number of clinical imaging mysteries and may enable more effective development of new clinical imaging methods.

Physics of MRI: a primer.

PubMed

Plewes, Donald B; Kucharczyk, Walter

2012-05-01

This article is based on an introductory lecture given for the past many years during the "MR Physics and Techniques for Clinicians" course at the Annual Meeting of the ISMRM. This introduction is not intended to be a comprehensive overview of the field, as the subject of magnetic resonance imaging (MRI) physics is large and complex. Rather, it is intended to lay a conceptual foundation by which magnetic resonance image formation can be understood from an intuitive perspective. The presentation is nonmathematical, relying on simple models that take the reader progressively from the basic spin physics of nuclei, through descriptions of how the magnetic resonance signal is generated and detected in an MRI scanner, the foundations of nuclear magnetic resonance (NMR) relaxation, and a discussion of the Fourier transform and its relation to MR image formation. The article continues with a discussion of how magnetic field gradients are used to facilitate spatial encoding and concludes with a development of basic pulse sequences and the factors defining image contrast. Copyright © 2012 Wiley Periodicals, Inc.

Biological effects of exposure to magnetic resonance imaging: an overview

PubMed Central

Formica, Domenico; Silvestri, Sergio

2004-01-01

The literature on biological effects of magnetic and electromagnetic fields commonly utilized in magnetic resonance imaging systems is surveyed here. After an introduction on the basic principles of magnetic resonance imaging and the electric and magnetic properties of biological tissues, the basic phenomena to understand the bio-effects are described in classical terms. Values of field strengths and frequencies commonly utilized in these diagnostic systems are reported in order to allow the integration of the specific literature on the bio-effects produced by magnetic resonance systems with the vast literature concerning the bio-effects produced by electromagnetic fields. This work gives an overview of the findings about the safety concerns of exposure to static magnetic fields, radio-frequency fields, and time varying magnetic field gradients, focusing primarily on the physics of the interactions between these electromagnetic fields and biological matter. The scientific literature is summarized, integrated, and critically analyzed with the help of authoritative reviews by recognized experts, international safety guidelines are also cited. PMID:15104797

Spinning angle optical calibration apparatus

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

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

1991-02-26

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

High-acoustic-impedance tantalum oxide layers for insulating acoustic reflectors.

PubMed

Capilla, Jose; Olivares, Jimena; Clement, Marta; Sangrador, Jesús; Iborra, Enrique; Devos, Arnaud

2012-03-01

This work describes the assessment of the acoustic properties of sputtered tantalum oxide films intended for use as high-impedance films of acoustic reflectors for solidly mounted resonators operating in the gigahertz frequency range. The films are grown by sputtering a metallic tantalum target under different oxygen and argon gas mixtures, total pressures, pulsed dc powers, and substrate biases. The structural properties of the films are assessed through infrared absorption spectroscopy and X-ray diffraction measurements. Their acoustic impedance is assessed by deriving the mass density from X-ray reflectometry measurements and the acoustic velocity from picosecond acoustic spectroscopy and the analysis of the frequency response of the test resonators.

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

High Field Small Animal Magnetic Resonance Oncology Studies

PubMed Central

Bokacheva, Louisa; Ackerstaff, Ellen; LeKaye, H. Carl; Zakian, Kristen; Koutcher, Jason A.

2014-01-01

This review focuses on the applications of high magnetic field magnetic resonance imaging (MRI) and spectroscopy (MRS) to cancer studies in small animals. High field MRI can provide information about tumor physiology, the microenvironment, metabolism, vascularity and cellularity. Such studies are invaluable for understanding tumor growth and proliferation, response to treatment and drug development. The MR techniques reviewed here include 1H, 31P, Chemical Exchange Saturation Transfer (CEST) imaging, and hyperpolarized 13C MR spectroscopy as well as diffusion-weighted, Blood Oxygen Level Dependent (BOLD) contrast imaging, and dynamic contrast-enhanced MR imaging. These methods have been proven effective in animal studies and are highly relevant to human clinical studies. PMID:24374985

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.

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

DNP-enhanced ultrawideline 207Pb solid-state NMR spectroscopy: an application to cultural heritage science

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

Kobayashi, Takeshi; Perras, Frederic A.; Murphy, Anna

Dynamic nuclear polarization (DNP) is used to enhance the (ultra)wideline 207Pb solid-state NMR spectra of lead compounds of relevance in the preservation of cultural heritage objects. The DNP SSNMR experiments enabled, for the first time, the detection of the basic lead carbonate phase of the lead white pigment by 207Pb SSNMR spectroscopy. Variable-temperature experiments revealed that the short T'2 relaxation time of the basic lead carbonate phase hinders the acquisition of the NMR signal at room temperature. We additionally observe that the DNP enhancement is twice as large for lead palmitate (a lead soap, which is a degradation product implicatedmore » in the visible deterioration of lead-based oil paintings), than it is for the basic lead carbonate. As a result, this enhancement has allowed us to detect the formation of a lead soap in an aged paint film by 207Pb SSNMR spectroscopy; which may aid in the detection of deterioration products in smaller samples removed from works of art.« less

DNP-enhanced ultrawideline 207Pb solid-state NMR spectroscopy: an application to cultural heritage science

DOE PAGES

Kobayashi, Takeshi; Perras, Frederic A.; Murphy, Anna; ...

2017-02-17

Dynamic nuclear polarization (DNP) is used to enhance the (ultra)wideline 207Pb solid-state NMR spectra of lead compounds of relevance in the preservation of cultural heritage objects. The DNP SSNMR experiments enabled, for the first time, the detection of the basic lead carbonate phase of the lead white pigment by 207Pb SSNMR spectroscopy. Variable-temperature experiments revealed that the short T'2 relaxation time of the basic lead carbonate phase hinders the acquisition of the NMR signal at room temperature. We additionally observe that the DNP enhancement is twice as large for lead palmitate (a lead soap, which is a degradation product implicatedmore » in the visible deterioration of lead-based oil paintings), than it is for the basic lead carbonate. As a result, this enhancement has allowed us to detect the formation of a lead soap in an aged paint film by 207Pb SSNMR spectroscopy; which may aid in the detection of deterioration products in smaller samples removed from works of art.« less

Examination of gamma-irradiated fruits and vegetables by electron spin resonance spectroscopy

NASA Astrophysics Data System (ADS)

Desrosiers, Marc F.; McLaughlin, William L.

The ESR spectra of the seeds, pits, shells, and skins of a variety of irradiated fruits and vegetables were measured. All spectra, control and irradiated, contained a single resonance with a g-factor of 2.00. Additional resonances due to Mn 2+ were observed for the drupelets of blackberries and red raspberries. An unusual radiation-induced radical was observed for irradiated mango seed; however, the signal decayed completely within a few days. It was concluded that only in a few specialized cases could the ESR resonances observed be suitable for postirradiation monitoring or dosimetry.

Free-standing epitaxial graphene.

PubMed

Shivaraman, Shriram; Barton, Robert A; Yu, Xun; Alden, Jonathan; Herman, Lihong; Chandrashekhar, Mvs; Park, Jiwoong; McEuen, Paul L; Parpia, Jeevak M; Craighead, Harold G; Spencer, Michael G

2009-09-01

We report on a method to produce free-standing graphene sheets from epitaxial graphene on silicon carbide (SiC) substrate. Doubly clamped nanomechanical resonators with lengths up to 20 microm were patterned using this technique and their resonant motion was actuated and detected optically. Resonance frequencies of the order of tens of megahertz were measured for most devices, indicating that the resonators are much stiffer than expected for beams under no tension. Raman spectroscopy suggests that the graphene is not chemically modified during the release of the devices, demonstrating that the technique is a robust means of fabricating large-area suspended graphene structures.

Valence-band structure of the ferromagnetic semiconductor GaMnAs studied by spin-dependent resonant tunneling spectroscopy.

PubMed

Ohya, Shinobu; Muneta, Iriya; Hai, Pham Nam; Tanaka, Masaaki

2010-04-23

The valence-band structure and the Fermi level (E(F)) position of ferromagnetic-semiconductor GaMnAs are quantitatively investigated by electrically detecting the resonant tunneling levels of a GaMnAs quantum well (QW) in double-barrier heterostructures. The resonant level from the heavy-hole first state is clearly observed in the metallic GaMnAs QW, indicating that holes have a high coherency and that E(F) exists in the band gap. Clear enhancement of tunnel magnetoresistance induced by resonant tunneling is demonstrated in these double-barrier heterostructures.

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

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.

Laser engines operating by resonance absorption. [thermodynamic feasibility study

NASA Technical Reports Server (NTRS)

Garbuny, M.; Pechersky, M. J.

1976-01-01

Basic tutorial article on the thermodynamic feasibility of laser engines at the present state of the art. Three main options are considered: (1) laser power applied externally to a heat reservoir (boiler approach); (2) internal heating of working fluid by resonance absorption; and (3) direct conversion of selective excitation into work. Only (2) is considered practically feasible at present. Basic concepts and variants, efficiency relations, upper temperature limits of laser engines, selection of absorbing gases, engine walls, bleaching, thermodynamic cycles of optimized laser engines, laser-powered turbines, laser heat pumps are discussed. Photon engines and laser dissociation engines are also considered.

Avoided-Level-Crossing Spectroscopy with Dressed Matter Waves

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

Eckardt, Andre; Holthaus, Martin

2008-12-12

We devise a method for probing resonances of macroscopic matter waves in shaken optical lattices by monitoring their response to slow parameter changes, and show that such resonances can be disabled by particular choices of the driving amplitude. The theoretical analysis of this scheme reveals far-reaching analogies between dressed atoms and time periodically forced matter waves.

Avoided-Level-Crossing Spectroscopy with Dressed Matter Waves

NASA Astrophysics Data System (ADS)

Eckardt, André; Holthaus, Martin

2008-12-01

We devise a method for probing resonances of macroscopic matter waves in shaken optical lattices by monitoring their response to slow parameter changes, and show that such resonances can be disabled by particular choices of the driving amplitude. The theoretical analysis of this scheme reveals far-reaching analogies between dressed atoms and time periodically forced matter waves.

Resonant and Nonresonant Nonlinear Optical Spectroscopy of CDSE Quantum Dots for Nonlinear Photonic Applications

DTIC Science & Technology

2006-11-01

Temple D., Yoo K. P., Kim S. Y., Mott A., Namkung M., and Jung S. S., 2003: Large and pure refractive nonlinearity of nanostructure silica ... aerogel , Appl. Phys. Lett., 82(25), 4444-4446. [18] Sun W., Patton T., Stultz L., andClaude J. P., 2003: Resonant third-order nonlinearities of tetrakis