EarlyView Articles

CARS diagnostics of fluid phase behavior in small mesopores at near‐critical temperatures

Published: Apr 9, 2013

Author(s): V. G. Arakcheev, V. B. Morozov

Journal: Journal of Raman Spectroscopy

Coherent anti‐Stokes Raman scattering (CARS) spectroscopy is applied to investigate the fluid phase behavior in small mesopores at bulk sub‐ and supercritical temperatures. CARS spectra of the Q‐branch (1388 cm−1) of carbon dioxide were measured at isothermal compression in pores of two nanoporous glass samples with pore radii of 2 and 3.5 nm. The spectral transformations with pressure of the fluid indicate the formation of a condensed phase in the...

Rapid multi‐echo measurement of brain metabolite T ₂ values at 7 T using a single‐shot spectroscopic Carr–Purcell–Meiboom–Gill sequence and prior information

Published: Apr 7, 2013

Author(s): Itamar Ronen, Ece Ercan, Andrew Webb

Journal: NMR in Biomedicine

We present a method for the robust and accurate estimation of brain metabolite transverse relaxation times (T2) from multiple spin‐echo data acquired with a single‐shot Carr–Purcell–Meiboom–Gill (CPMG) spectroscopic sequence. Each acquired echo consists of a small number of complex time‐domain data points. The amplitudes of the spectral components in each echo are calculated by solving a set of linear equations in which previously estimated...

Assessment of gadoxetate DCE‐MRI as a biomarker of hepatobiliary transporter inhibition

Published: Apr 7, 2013

Author(s): Jose L. Ulloa, Simone Stahl, James Yates, Neil Woodhouse, J. Gerry Kenna, Huw B. Jones, John C. Waterton, Paul D. Hockings

Journal: NMR in Biomedicine

Drug‐induced liver injury (DILI) is a clinically important adverse drug reaction, which prevents the development of many otherwise safe and effective new drugs. Currently, there is a lack of sensitive and specific biomarkers that can be used to predict, assess and manage this toxicity. The aim of this work was to evaluate gadoxetate‐enhanced MRI as a potential novel biomarker of hepatobiliary transporter inhibition in the rat. Initially,...

Vibrational characterization and surface‐enhanced Raman scattering detection of probenecid doping drug

Published: Apr 5, 2013

Author(s): Irene Izquierdo‐Lorenzo, José Vicente García‐Ramos, Santiago Sanchez‐Cortes

Journal: Journal of Raman Spectroscopy

Probenecid (PB), a drug employed to reduce the excretion of other drugs in urine and also employed as masking agent in sport doping, is characterized for the first time in this work by vibrational spectroscopy. Previously, FTIR and FT‐Raman spectra were assigned on the basis of density functional theory calculations. Afterwards, a detection protocol of PB was developed on the basis of surface‐enhanced Raman scattering (SERS) spectroscopy....

Fiber type characterization in skeletal muscle by diffusion tensor imaging

Published: Apr 4, 2013

Author(s): Michael Scheel, Philipp Roth, Tobias Winkler, Adamantios Arampatzis, Torben Prokscha, Bernd Hamm, Gerd Diederichs

Journal: NMR in Biomedicine

Fiber type distribution within a skeletal muscle, i.e. the quantification of the relative amount of type 1 (slow‐twitching) and type 2 (fast‐twitching) muscle fibers, is of great interest for the monitoring of the effects of training or the treatment of muscle diseases. The purpose of this study was to determine the feasibility of diffusion tensor imaging (DTI) as a tool for noninvasive fiber type quantification in human skeletal muscle....

Amide proton transfer imaging of the human breast at 7T: development and reproducibility

Published: Apr 4, 2013

Author(s): Dennis W. J. Klomp, Adrienne N. Dula, Lori R. Arlinghaus, Michel Italiaander, Richard D. Dortch, Zhongliang Zu, Jason M. Williams, Daniel F. Gochberg, Peter R. Luijten, John C. Gore, Thomas E. Yankeelov, Seth A. Smith

Journal: NMR in Biomedicine

Chemical exchange saturation transfer (CEST) can offer information about protons associated with mobile proteins through the amide proton transfer (APT) effect, which has been shown to discriminate tumor from healthy tissue and, more recently, has been suggested as a prognosticator of response to therapy. Despite this promise, APT effects are small (only a few percent of the total signal), and APT imaging is often prone to artifacts...

Mapping glutamate in subcortical brain structures using high‐resolution GluCEST MRI

Published: Apr 3, 2013

Author(s): Kejia Cai, Anup Singh, David R. Roalf, Ravi Prakash Reddy Nanga, Mohammad Haris, Hari Hariharan, Ruben Gur, Ravinder Reddy

Journal: NMR in Biomedicine

In vivo measurement of glutamate (Glu) in brain subcortex can elucidate the role these structures play in cognition and neuropsychiatric disorders. However, accurate quantification of Glu in subcortical regions is challenging. Recently, a novel MRI method based on the Glu chemical exchange saturation transfer (GluCEST) effect has been developed for detecting brain Glu in millimolar concentrations. Here, we use GluCEST to map Glu...

The pit transition potential in the repassivation of aluminium alloys

Published: Apr 3, 2013

Author(s): Ilaria M. Comotti, Monica Trueba, Stefano P. Trasatti

Journal: Surface and Interface Analysis

This paper reports a systematic investigation of corrosion in 0.6 mol/l NaCl of freshly polished 1050‐H24, 6082‐T6, 2024‐T3 and 7075‐T6 Al alloys by single‐cycle anodic polarization using different anodic current limits for scan reversal (irev). For all alloys but Al 1050‐H24, an inflection point was repeatedly identified in the reverse curve in most experimental conditions. This feature was correlated with constricted localized attack other than...

A concise review of HPLC, LC‐MS and LC‐MS/MS methods for determination of azithromycin in various biological matrices

Published: Apr 3, 2013

Author(s): Kuldeep Sharma, Ramesh Mullangi

Journal: Biomedical Chromatography

ABSTRACT Azithromycin is one of the best selling antibiotics in the world. It belongs to the new macrolide family of azalides. It is derived from erythromycin and it differs from erythromycin in having a 15‐membered ring and a methyl substituted nitrogen inserted at the 9a position in the aglycone ring. This structural modification confers favourable microbiological and pharmacokinetic characteristics on azithromycin and greater...

Adiabatic multi‐echo ³¹ P spectroscopic imaging (AMESING) at 7 T for the measurement of transverse relaxation times and regaining of sensitivity in tissues with short T ₂ * values

Published: Apr 2, 2013

Author(s): W. J. M. Kemp, V. O. Boer, P. R. Luijten, B. L. Stehouwer, W. B. Veldhuis, D. W. J. Klomp

Journal: NMR in Biomedicine

An adiabatic multi‐echo spectroscopic imaging (AMESING) sequence, used for 31P MRSI, with spherical k‐space sampling and compensated phase‐encoding gradients, was implemented on a whole‐body 7‐T MR system. One free induction decay (FID) and up to five symmetric echoes can be acquired with this sequence. In tissues with low T2* and high T2, this can theoretically lead to a potential maximum signal‐to‐noise ratio (SNR) increase of almost a factor of three,...

A calibration‐based approach to real‐time in vivo monitoring of pyruvate C ₁ and C ₂ polarization using the J_CC spectral asymmetry

Published: Apr 2, 2013

Author(s): Justin Y. C. Lau, Albert P. Chen, Yi‐Ping Gu, Charles H. Cunningham

Journal: NMR in Biomedicine

A calibration‐based technique for real‐time measurement of pyruvate polarization by partial integral analysis of the doublet from the neighbouring J‐coupled carbon is presented. In vitro calibration data relating the C2 and C1 asymmetries to the instantaneous C1 and C2 polarizations, respectively, were acquired in blood. The feasibility of using the in vitro calibration data to determine the instantaneous in vivo C1 and C2 polarizations was demonstrated in the...

Preparation and analytical characterization of 1‐(1‐phenylcyclohexyl)piperidine (PCP) and 1‐(1‐phenylcyclohexyl)pyrrolidine (PCPy) analogues

Published: Apr 2, 2013

Author(s): Jason Wallach, Giorgia De Paoli, Adeboye Adejare, Simon D. Brandt

Journal: Drug Testing and Analysis

Classic examples of psychoactive arylcycloalkylamines include ketamine and 1‐(1‐phenylcyclohexyl)piperidine (PCP) and many others serve as important structural templates for neuropharmacological research. The recent emergence of PCP analogues that can be obtained from internet retailers requires the implementation of appropriate monitoring strategies for harm reduction purposes. Access to analytical data plays a key part when encountering...

Spectroscopic characterization of graphene films grown on Pt(111) surface by chemical vapor deposition of ethylene

Published: Apr 2, 2013

Author(s): Enzo Cazzanelli, T. Caruso, M. Castriota, A. R. Marino, A. Politano, G. Chiarello, M. Giarola, G. Mariotto

Journal: Journal of Raman Spectroscopy

This work reports the peculiar properties of a graphene film prepared by the chemical vapor deposition of ethylene in high vacuum on a well oriented and carefully cleaned Pt(111) crystal surface maintained at high temperature. In‐situ and ex‐situ characterization techniques (low‐energy electron diffraction, high‐resolution electron energy loss spectroscopy, scanning electron microscopy and Raman micro‐spectroscopy) used here indicate the prevalence...

Measuring mitochondrial metabolism in rat brain in vivo using MR Spectroscopy of hyperpolarized [2‐ ¹³ C]pyruvate

Published: Apr 1, 2013

Author(s): Jae Mo Park, Sonal Josan, Thomas Grafendorfer, Yi‐Fen Yen, Ralph E. Hurd, Daniel M. Spielman, Dirk Mayer

Journal: NMR in Biomedicine

Hyperpolarized [1‐13C]pyruvate ([1‐13C]Pyr) has been used to assess metabolism in healthy and diseased states, focusing on the downstream labeling of lactate (Lac), bicarbonate and alanine. Although hyperpolarized [2‐13C]Pyr, which retains the labeled carbon when Pyr is converted to acetyl‐coenzyme A, has been used successfully to assess mitochondrial metabolism in the heart, the application of [2‐13C]Pyr in the study of brain metabolism has been...

The use of X‐ray interaction data to differentiate malignant from normal breast tissue at surgical margins and biopsy analysis

Published: Apr 1, 2013

Author(s): M. J. Farquharson, A. Al‐Ebraheem, S. Cornacchi, G. Gohla, P. Lovrics

Journal: X-Ray Spectrometry

X‐ray interaction data, including measuring bio‐metal levels and scattering characteristics, are being shown to be a possible discriminating variable in the classification of human tissues. However, a major concern when using X‐ray interaction data in breast cancer material is that the samples are rarely 100% tumour because of the invasive nature of the disease. The work reported here includes a methodology to help overcome this...

Determination of phosphorus and other elements in atmospheric aerosols using synchrotron total‐reflection X‐ray fluorescence

Published: Apr 1, 2013

Author(s): Ursula E. A. Fittschen, Christina Streli, Florian Meirer, Matthias Alfeld

Journal: X-Ray Spectrometry

In this study, P and other low Z elements were determined in aerosol particulates from ambient air using synchrotron radiation‐induced total‐reflection X‐ray fluorescence analysis. Atmospheric transport of nutrients such as P or Si to the oceans is a key factor to marine plankton growth. Concentration of these elements in marine air masses is generally low (P < 10 ng/m3). Therefore, analytical procedures enabling...

Case report of accidental poisoning with the tranquilizer xylazine and the anesthetic ketamine confirmed by qualitative and quantitative toxicological analysis using GC‐MS and LC‐MS ⁿ

Published: Apr 1, 2013

Author(s): Golo M.J. Meyer, Markus R. Meyer, Bernhard Mischo, Otto Schofer, Hans H. Maurer

Journal: Drug Testing and Analysis

Connection between the vibrational dynamics and the cross‐linking properties in cyclodextrins‐based polymers

Published: Mar 31, 2013

Author(s): Vincenza Crupi, Aldo Fontana, Marco Giarola, Domenico Majolino, Gino Mariotto, Andrea Mele, Lucio Melone, Carlo Punta, Barbara Rossi, Francesco Trotta, Valentina Venuti

Journal: Journal of Raman Spectroscopy

The vibrational dynamics of a new class of cross‐linked polymers obtained from both native and modified cyclodextrin, referred to as cyclodextrin nanosponges, is here investigated. The main purpose is to spot the structure of these materials at molecular level unlikely to be characterized by diffraction methods due to the low or null degree of crystallinity. The analysis of the spectral features of the vibrational bands observed between...

Polarized micro‐Raman spectroscopy and ab initio phonon modes calculations of LuPO ₄

Published: Mar 31, 2013

Author(s): A. Sanson, M. Giarola, M. Bettinelli, A. Speghini, G. Mariotto

Journal: Journal of Raman Spectroscopy

The vibrational dynamics of lutetium orthophosphate (LuPO4) single crystals was carefully investigated by means of polarized micro‐Raman spectroscopy and ab initio calculations. Eleven of the twelve independent components of the polarizability tensor, expected on the basis of the group theory for LuPO4, were selected in turn and assigned in symmetry. The only B1g(2) Raman mode was not observed, likewise due to either its very small intensity or its nearness in...

Investigation of field and diffusion time dependence of the diffusion‐weighted signal at ultrahigh magnetic fields

Published: Mar 27, 2013

Author(s): Nicolas Kunz, Stéphane V. Sizonenko, Petra S. Hüppi, Rolf Gruetter, Yohan Looij

Journal: NMR in Biomedicine

Over the last decade, there has been a significant increase in the number of high‐magnetic‐field MRI magnets. However, the exact effect of a high magnetic field strength (B0) on diffusion‐weighted MR signals is not yet fully understood. The goal of this study was to investigate the influence of different high magnetic field strengths (9.4 T and 14.1 T) and diffusion times (9, 11, 13, 15, 17 and 24 ms) on the diffusion‐weighted signal in...