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Journal articles on the topic 'Short te spectroscopy'

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Published: 3 September 2022

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1

Ko, Eun Hye, Gwang Woo Jeong, Jeong Jin Seo, Heoung Keun Kang, Shin Jung, Sam Suk Kang, and Min Cheol Lee. "Usefulness of Short TE Proton MR Spectroscopy in Grading Brain Glial Tumors." Journal of the Korean Radiological Society 42, no. 3 (2000): 403. http://dx.doi.org/10.3348/jkrs.2000.42.3.403.

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2

Cordery, R. J., D. MacManus, A. Godbolt, M. N. Rossor, and A. D. Waldman. "Short TE Quantitative Proton Magnetic Resonance Spectroscopy in Variant Creutzfeldt-Jakob Disease." European Radiology 16, no. 8 (January 12, 2006): 1692–98. http://dx.doi.org/10.1007/s00330-005-0090-4.

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3

Paschoal, André Monteiro, Fernando Fernandes Paiva, and Renata Ferranti Leoni. "Dual-Echo Arterial Spin Labeling for Brain Perfusion Quantification and Functional Analysis." Concepts in Magnetic Resonance Part A 2019 (August 1, 2019): 1–7. http://dx.doi.org/10.1155/2019/5040465.

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Arterial Spin Labeling (ASL) is a noninvasive MRI-based method to measure cerebral blood flow (CBF). Recently, the study of ASL as a functional tool has emerged once CBF fluctuation comes from capillaries in brain tissue, giving a more spatially specific response when compared to the standard functional MRI method, based on the blood oxygenation level-dependent (BOLD) contrast. Although the BOLD effect could be desirable to study brain function, if one aims to quantify CBF, such effect is considered contamination that can be more attenuated if short TE value is used in the image acquisition. An approach that provides both CBF and function information in a simultaneous acquisition is the use of a dual-echo ASL (DE-ASL) readout. Our purpose was to evaluate the information provided by DE-ASL regarding CBF quantification and functional connectivity with a motor task. Pseudocontinuous ASL of twenty healthy subjects (age: 32.4 ± 10.2 years, 13 male) was acquired at a 3T scanner. We analyzed the influence of TE on CBF values and brain connectivity provided by CBF and concurrent BOLD (cc-BOLD) time series. Brain networks were obtained by the general linear model and independent component analysis. Connectivity matrices were generated using a bivariate correlation (Fisher Z values). No effect of the sequence readout, but significant effect of the TE value, was observed on gray matter CBF values. Motor networks with reduced extension and more connections with important regions for brain integration were observed for CBF data acquired with short TE, proving its higher spatial specificity. Therefore, it was possible to use a dual-echo readout provided by a standard commercial ASL pulse sequence to obtain reliable quantitative CBF values and functional information simultaneously.
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4

Yang, Pinchen, Ming-Ting Wu, Shih-Shan Dung, and Cheng-Wen Ko. "Short-TE proton magnetic resonance spectroscopy investigation in adolescents with attention-deficit hyperactivity disorder." Psychiatry Research: Neuroimaging 181, no. 3 (March 2010): 199–203. http://dx.doi.org/10.1016/j.pscychresns.2009.10.001.

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Walecki, Jerzy, Maria Sokól, Piotr Pieniążek, Bogusław Maciejewski, Rafał Tarnawski, Teresa Krupska, Jerzy Wydmański, Jacek Brzeziński, and Paweł Grieb. "Role of short TE 1H-MR spectroscopy in monitoring of post-operation irradiated patients." European Journal of Radiology 30, no. 2 (May 1999): 154–61. http://dx.doi.org/10.1016/s0720-048x(99)00053-4.

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6

Wenger, Katharina J., Elke Hattingen, Kea Franz, Joachim Steinbach, Oliver Bähr, and Ulrich Pilatus. "In vivo Metabolic Profiles as Determined by 31P and short TE 1H MR-Spectroscopy." Clinical Neuroradiology 29, no. 1 (October 5, 2017): 27–36. http://dx.doi.org/10.1007/s00062-017-0630-8.

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7

Brostow, Witold, IKang Chen, and Haley E. Hagg Lobland. "Polymeric Coatings for Skutterudite-Based Thermoelectric Materials." Lubricants 10, no. 4 (April 18, 2022): 72. http://dx.doi.org/10.3390/lubricants10040072.

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Thermoelectric (TE) devices have short service lives. These materials undergo thermal degradation at elevated temperatures by processes such as oxidation or sublimation. Our substrates were skutterudite-based TE materials. We covered their surfaces with a liquid high-temperature polymer (HTP)—crosslinked after the deposition, what converted those surfaces into solid coatings. Sintering was performed at 250 °C for times of up to 48 h on both uncoated (control) and HTP-coated samples. The changes caused by thermal degradation were evaluated by thermogravimetric analysis, electrical resistivity, and energy-dispersive X-ray spectroscopy, and observed by scanning electron microscopy. Significant mitigation of oxidation and sublimation of our TE materials was achieved.
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8

Jiao, Fei, Chong-an Di, Yimeng Sun, Peng Sheng, Wei Xu, and Daoben Zhu. "Inkjet-printed flexible organic thin-film thermoelectric devices based on p- and n-type poly(metal 1,1,2,2-ethenetetrathiolate)s/polymer composites through ball-milling." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 372, no. 2013 (April 13, 2014): 20130008. http://dx.doi.org/10.1098/rsta.2013.0008.

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In this article, we put forward a simple method for the synthesis of thermoelectric (TE) composite materials. Both n- and p-type composites were obtained by ball-milling the insoluble and infusible metal coordination polymers with other polymer solutions. The particle size, film morphology and composition were characterized by dynamic light scattering, scanning electron microscopy, transmission electron microscopy and energy-dispersive X-ray spectroscopy. The TE properties of the drop-cast composite film were measured at different temperatures. An inkjet-printed flexible device was fabricated and the output voltage and short-circuit current at various hot-side temperatures ( T hot ) and temperature gradients (Δ T ) were tested. The composite material not only highly maintained the TE properties of the pristine material but also greatly improved its processability. This method can be extended to other insoluble and infusible TE materials for solution-processed flexible TE devices.
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9

Aghakhanyan, Gayane, Giancarlo Lupi, Francesca Frijia, Hlavata Hana, Francesco Lombardo, Sara De Cori, Raffaello Canapicchi, Riccardo Vannozzi, and Domenico Montanaro. "Delayed Post-Traumatic Fronto-Ethmoidal Sinus Mucocele Evaluated with Short and Long TE MR Spectroscopy." Neuroradiology Journal 26, no. 6 (December 2013): 693–98. http://dx.doi.org/10.1177/197140091302600613.

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10

Boer, Vincent O., Jeroen C. W. Siero, Hans Hoogduin, Jetse S. van Gorp, Peter R. Luijten, and Dennis W. J. Klomp. "High-field MRS of the human brain at short TE and TR." NMR in Biomedicine 24, no. 9 (February 10, 2011): 1081–88. http://dx.doi.org/10.1002/nbm.1660.

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11

Kaur, Rajinder, Atul Khanna, Hirdesh, Ann-Christin Dippel, Olof Gutowski, Fernando González, and Marina González-Barriuso. "Structure of strontium tellurite glass, anti-glass and crystalline phases by high-energy X-ray diffraction, reverse Monte Carlo and Rietveld analysis." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 76, no. 1 (January 28, 2020): 108–21. http://dx.doi.org/10.1107/s2052520620000025.

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The structures of xSrO–(100 − x)TeO2 (x = 5, 7.5, 8.5 and 10 mol.%) glass, anti-glass and crystalline samples were studied by high-energy X-ray diffraction (HEXRD), reverse Monte Carlo (RMC) simulations, atomic pair distribution function analysis and Fullprof Rietveld refinement. The atomic pair distributions show the first peak at 1.90 Å due to the Te—O equatorial bonds and the Te—O peak is asymmetrical due to the range of Te—O bond lengths in glass, anti-glass and crystalline samples. The short-range structural properties of glasses such as Te—O bond lengths, Te–O speciation, Te–Te distances and O—Te—O bond angle distributions were determined by RMC simulations. The average Te–O coordination number (N Te–O) for 5SrO–95TeO2 glass is 3.93 which decreases to 3.59 on increasing the SrO concentration to 10 mol.%. The changes in N Te–O revealed that the glass network predominantly contains TeO4 units with a small amount of TeO3 units and there is a structural transformation TeO4 → TeO3 with an increase in SrO concentration. The O—Te—O bond angle distributions have a peak at 79° and reveal that the Oequatorial—Te—Oequatorial bonds are the most abundant linkages in the tellurite network. Two glass samples containing 7.5 and 8.5 mol.% of SrO were annealed at 350°C for 1 h to produce anti-glass phases; they were further annealed at 450°C for 4 h to transform them into crystalline phases. The anti-glass samples are disordered cubic SrTe5O11 and the disordered monoclinic SrTeO3 phases, whereas the crystalline samples contain monoclinic SrTeO3 and the orthorhombic TeO2 phases. The unit-cell parameters of the anti-glass and crystalline structures were determined by Fullprof Rietveld refinement. Thermal studies found that the glass transition temperature increases with an increase in SrO mol.% and the results on the short-range structure of glasses from Raman spectroscopy are in agreement with the RMC findings.
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12

Chung, Jin Il, Dong Ik Kim, Byung In Lee, Seung Ik Lee, and Pyeong Ho Yoon. "Hippocampal and Neocortical Metabolite Ratio in Patients with Complex Partial Seizure: Short TE and Long TE Techniques Using Single Voxel Proton MR Spectroscopy." Journal of the Korean Radiological Society 43, no. 2 (2000): 125. http://dx.doi.org/10.3348/jkrs.2000.43.2.125.

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13

Basharat, Meer, Maysam Jafar, Nandita M. deSouza, and Geoffrey S. Payne. "Evaluation of short‐TE 1 H MRSI for quantification of metabolites in the prostate." NMR in Biomedicine 27, no. 4 (February 12, 2014): 459–67. http://dx.doi.org/10.1002/nbm.3082.

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14

Maghsudi, Helen, Birte Schmitz, Andrew A. Maudsley, Sulaiman Sheriff, Paul Bronzlik, Martin Schütze, Heinrich Lanfermann, and Xiaoqi Ding. "Regional Metabolite Concentrations in Aging Human Brain: Comparison of Short-TE Whole Brain MR Spectroscopic Imaging and Single Voxel Spectroscopy at 3T." Clinical Neuroradiology 30, no. 2 (January 18, 2019): 251–61. http://dx.doi.org/10.1007/s00062-018-00757-x.

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15

Server, Andres, Roger Josefsen, Bettina Kulle, Jan Mæhlen, Till Schellhorn, Øystein Gadmar, Theresa Kumar, Monika Haakonsen, Carl W. Langberg, and Per H. Nakstad. "Proton magnetic resonance spectroscopy in the distinction of high-grade cerebral gliomas from single metastatic brain tumors." Acta Radiologica 51, no. 3 (April 2010): 316–25. http://dx.doi.org/10.3109/02841850903482901.

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Background: Brain metastases and primary high-grade gliomas, including glioblastomas multiforme (GBM) and anaplastic astrocytomas (AA), may be indistinguishable by conventional magnetic resonance (MR) imaging. Identification of these tumors may have therapeutic consequences. Purpose: To assess the value of MR spectroscopy (MRS) using short and intermediate echo time (TE) in differentiating solitary brain metastases and high-grade gliomas on the basis of differences in metabolite ratios in the intratumoral and peritumoral region. Material and Methods: We performed MR imaging and MRS in 73 patients with histologically verified intraaxial brain tumors: 53 patients with high-grade gliomas (34 GBM and 19 AA) and 20 patients with metastatic brain tumors. The metabolite ratios of Cho/Cr, Cho/NAA, and NAA/Cr at intermediate TE and the presence of lipids at short TE were assessed from spectral maps in the tumoral core, peritumoral edema, and contralateral normal-appearing white matter. The differences in the metabolite ratios between high-grade gliomas/GBM/AA and metastases were analyzed statistically. Cutoff values of Cho/Cr, Cho/NAA, and NAA/Cr ratios in the peritumoral edema, as well as Cho/Cr and NAA/Cr ratios in the tumoral core for distinguishing high-grade gliomas/GBM/AA from metastases were determined by receiver operating characteristic (ROC) curve analysis. Results: Significant differences were noted in the peritumoral Cho/Cr, Cho/NAA, and NAA/ Cr ratios between high-grade gliomas/GBM/AA and metastases. ROC analysis demonstrated a cutoff value of 1.24 for peritumoral Cho/Cr ratio to provide sensitivity, specificity, positive (PPV), and negative predictive values (NPV) of 100%, 88.9%, 80.0%, and 100%, respectively, for discrimination between high-grade gliomas and metastases. By using a cutoff value of 1.11 for peritumoral Cho/NAA ratio, the sensitivity was 100%, the specificity was 91.1%, the PPV was 83.3%, and the NPV was 100%. Conclusion: The results of this study demonstrate that MRS can differentiate high-grade gliomas from metastases, especially with peritumoral measurements, supporting the hypothesis that MRS can detect infiltration of tumor cells in the peritumoral edema.
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16

Rohani Rankouhi, Seyedmorteza, Donghyun Hong, Hadrien Dyvorne, Priti Balchandani, and David G. Norris. "MASE-sLASER, a short-TE, matched chemical shift displacement error sequence for single-voxel spectroscopy at ultrahigh field." NMR in Biomedicine 31, no. 7 (June 1, 2018): e3940. http://dx.doi.org/10.1002/nbm.3940.

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17

Hirdesh, Atul Khanna, Margit Fábián, Ann-Christin Dippel, and Olof Gotowski. "Structure of lithium tellurite and vanadium lithium tellurite glasses by high-energy X-ray and neutron diffraction." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 77, no. 2 (March 24, 2021): 275–86. http://dx.doi.org/10.1107/s2052520621002274.

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xLi2O–(100 − x)TeO2 (x = 20 and 25 mol%) and xV2O5–(25 − x)Li2O–75TeO2 (x = 1, 2, 3, 4 and 5 mol%) glasses were prepared by melt-quenching and their thermal and structural properties were characterized by differential scanning calorimetry, Raman spectroscopy, high-energy X-ray diffraction and neutron diffraction and reverse Monte Carlo (RMC) simulations. The glass transition temperature increases steadily with an increase in V2O5 mol% in lithium tellurite glasses due to an increase in the average single bond energy of the glass network. The X-ray and neutron diffraction structure factors were modelled by RMC technique and the Te–O distributions show the first peak in the range 1.85–1.90 Å, with V–O = 1.75–1.95 Å, Li–O = 1.85–2.15 Å and O–O = 2.70–2.80 Å. The average Te–O coordination number decreases with an increase in Li2O mol% in lithium tellurite glasses, and the V—O coordination decreases from 5.12 to 3.81 with an increase in V2O5 concentration in vanadium lithium tellurite glasses. The O–Te–O, O–V–O, O–Li–O and O–O–O linkages have maxima in the ranges 86°–89°, 82°–87°, 80°–85° and at 59o, respectively. The structural analysis of tellurite glasses reveal significant short-range and medium-range disorder due to the existence of a wide range of Te–O and Te–Te distances in the first coordination shell.
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18

Sesselmann, Andreas, Ralf Hassdorf, Sebastian Zastrow, and Eckhard Müller. "High-Temperature Transport Properties of Indium Added Cobalt-Antimonide Based Skutterudites Processed by Current Assisted Short-Term Sintering." Advances in Science and Technology 74 (October 2010): 54–59. http://dx.doi.org/10.4028/www.scientific.net/ast.74.54.

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For more than a decade, skutterudites such as cobalt antimonides have been widely studied as a promising thermoelectric (TE) material for high-temperature applications. High thermoelectric figure of merit (ZT) in this material system can be achieved by suitable doping or by filling the interstitial voids with guest atoms. One of the best improvements in ZT is reported when indium (In) is used as additive to cobalt-antimonide skutterudites, as has been done in this study. Compaction of the grinded powders was carried out by a current-assisted short-term sintering device, which significantly reduces the process time in comparison to conventional hot pressing. Phase homogeneity of the bulk material has been probed by X-ray powder diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX). TE properties (i.e. electrical conductivity, Seebeck coefficient and thermal conductivity) have been analyzed in the temperature range from 300 K to 700 K. The functional homogeneity of the samples was screened by the Potential & Seebeck Microprobe (PSM). Adapted from these results the effect of indium addition to short-term sintered cobalt-antimonide based skutterudites with absence of impurity phases will be discussed.
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19

Tachrount, Mohamed, Guillaume Duhamel, Jérôme Laurin, Tanguy Marqueste, André Maues de Paula, Patrick Decherchi, Patrick J. Cozzone, and Virginie Callot. "In vivo short TE localized1H MR spectroscopy of mouse cervical spinal cord at very high magnetic field (11.75 T)." Magnetic Resonance in Medicine 69, no. 5 (June 12, 2012): 1226–32. http://dx.doi.org/10.1002/mrm.24360.

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20

Raininko, Raili, and Peter Mattsson. "Metabolite concentrations in supraventricular white matter from teenage to early old age: A short echo time 1h magnetic resonance spectroscopy (MRS) study." Acta Radiologica 51, no. 3 (April 2010): 309–15. http://dx.doi.org/10.3109/02841850903476564.

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Background: Age- and sex-related changes of metabolites in healthy adult brains have been examined with different 1H magnetic resonance spectroscopy (MRS) methods in varying populations, and with differing results. A long repetition time and short echo time technique reduces quantification errors due to T1 and T2 relaxation effects and makes it possible to measure metabolites with short T2 relaxation times. Purpose: To examine the effect of age on the metabolite concentrations measured by 1H MRS in normal supraventricular white matter using a long repetition time (TR) and a short echo time (TE). Material and Methods: Supraventricular white matter of 57 healthy subjects (25 women, 32 men), aged 13 to 72 years, was examined with a single-voxel MRS at 1.5T using a TR of 6000 ms and a TE of 22 ms. Tissue water was used as a reference in quantification. Results: Myoinositol increased slightly and total N-acetyl aspartate (NAA) decreased slightly with increasing age. Glutamine/glutamate complex (Glx) showed U-shaped age dependence, with highest concentrations in the youngest and oldest subjects. No significant age dependence was found in total choline and total creatine. No gender differences were found. Macromolecule/ lipid (ML) fractions were reliably measurable only in 36/57 or even fewer subjects and showed very large deviations. Conclusion: The concentrations of several metabolites in cerebral supraventricular white matter are age dependent on 1H MRS, even in young and middle-aged people, and age dependency can be nonlinear. Each 1H MRS study of the brain should therefore take age into account, whereas sex does not appear to be so important. The use of macromolecule and lipid evaluations is compromised by less successful quantification and large variations in healthy people.
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21

Inshasi, Jihad Said, Pournamy Sarathchandran, Mona Chetan Thakre, Nouf Saeed Al Talai, Reem Al Suwaidi, and Abubaker Al Madani. "Oral Cladribine is Effective in the Treatment of Tumefactive Demyelination in Relapsing Remitting Multiple Sclerosis – A Case Report." Open Neurology Journal 14, no. 1 (December 31, 2020): 109–14. http://dx.doi.org/10.2174/1874205x02014010109.

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This case report describes a 32-year old Emirati patient with tumefactive multiple sclerosis (TMS) treated with a short course of cladribine tablets. The patient presented initially with acute onset of progressive gait unsteadiness, lower limb weakness, associated with numbness of four days duration. Neurological examination of right arms and both legs weakness with sensory level at T10. Contrast-enhanced magnetic resonance imaging (MRI) of the brain showed a large tumefactive demyelination with multiple demyelinating lesions in the brain, consistent with a diagnosis of multiple sclerosis. MRI of the spine cervical and dorsal revealed multiple enhancing lesions as well. Cerebrospinal fluid oligoclonal bands were positive, and IgG index was high. Magnetic resonance spectroscopy showed elevation of lactate on short echo time (TE) and elevation of choline on long TE. The patient was treated with pulse steroid followed by oral cladribine as immune reconstitution therapy in the acute phase. The patient showed significant improvement clinically and radiologically to the treatment. The patient was followed up for 2 years and showed excellent resolution of the tumefactive lesion with no new lesions. Immune reconstitution therapy can be an option for treatment of tumefactive demyelination in multiple sclerosis in the acute setting. To our knowledge, there are no reports of the use of immune reconstitution therapies for the treatment of tumefactive lesions in multiple sclerosis.
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22

Frahm, J., and F. Hanefeld. "Single Voxel Proton MR Spectroscopy Methods and Applications in Neuropediatrics." Rivista di Neuroradiologia 13, no. 1 (February 2000): 7–15. http://dx.doi.org/10.1177/197140090001300103.

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The purpose of this contribution is to introduce quantitative single voxel proton MR spectroscopy of the human brain as an easy-to-use method for a noninvasive assessment of cellular composition and metabolism and to demonstrate its clinical potential in the field of neuropediatrics. The chosen approach transforms fully relaxed (TR = 6000 ms) short echo time (TE = 20 ms) proton MR spectra (STEAM localization sequence) into absolute metabolite concentrations by automatically fitting the raw data with a library of model spectra comprising all metabolites at known concentration (LCModel). The procedure includes total N-acetylaspartyl compounds as a marker for viable neuroaxonal tissue and myo-inositol as a purely glial constituent as well as total creatine, choline-containing compounds, glutamate and glutamine, and lactate. Extensive studies of brain disorders in childhood suggest the use of proton MRS as a promising tool for an in vivo histopathologic characterization of brain tissue. Typical metabolite patterns are observed for pathologic processes such as lactic acidosis, loss of functioning neurons, astrocytosis, myelin breakdown, or loss of oligodendrocytes. Examples deal with the diagnostic workup of enzyme deficiencies, demyelinating white matter diseases, and focal brain lesions.
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23

Sobola, Dinara, Pavel Kaspar, Alois Nebojsa, Dušan Hemzal, Lubomír Grmela, and Steve Smith. "Characterization of the native oxide on CdTe surfaces." Materials Science-Poland 37, no. 2 (June 1, 2019): 206–11. http://dx.doi.org/10.2478/msp-2019-0030.

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AbstractThis study focuses on the description of oxidation of CdTe monocrystal surfaces after selective chemical etching. Measurements of surface morphology of the oxides occurring in short time are valuable for deeper understanding of the material degradation and fabrication of reliable devices with enhanced performance. The samples with (1 1 1) orientation were selectively etched and cleaned of oxide. Exposure of the oxide-free surfaces of CdTe to air at normal atmospheric conditions over 24 hours leads to an appearance of characteristic surface features. The oxidized surfaces were investigated by scanning electron microscopy, scanning probe microscopy, Raman spectroscopy and ellipsometry. The results indicate clear differences in the oxidation of Cd-terminated and Te-terminated surfaces.
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Folkerts, Hella, Kurt Dehnicke, and Jörg Magull. "Synthese und Kristallstruktur von [TeCl2(NPMe3)2]2/ Synthesis and Crystal Structure of [TeCl2(NPMe3)2]2." Zeitschrift für Naturforschung B 50, no. 4 (April 1, 1995): 573–76. http://dx.doi.org/10.1515/znb-1995-0417.

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[TeCl2(NPMe3)2]2 has been prepared by the reaction of TeCl4 with Me3SiNPMe3 in acetonitrile solution. Tlie compound forms white moisture sensitive crystals which have been characterized by IR spectroscopy and by a crystal structure determination. Space group P21/c, Z = 2, structure solution with 3510 independent reflections, R = 0.029. Lattice dimensions at - 70 °C; a = 1206.0(9); b = 1054.7(7); c = 1156.0(6) pm; β = 99.27(5)°. [TeCl2(NPMe3)2]2 forms centrosymmetric molecules via TeCl2Te bridges with bond lengths Te-Cl of 267.2 and 366.9 pm, the longer one being in trans-position to one of the terminally bounded (NPMe3-) groups. The TeN bond lengths of 190.1 and 192.6 pm are unusually short.
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Orlov, V. G., and G. S. Sergeev. "Electronic band structure and chemical bonding in trigonal Se and Te." AIP Advances 12, no. 5 (May 1, 2022): 055110. http://dx.doi.org/10.1063/5.0087880.

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Herein, the electronic band structure and charge density distribution are theoretically studied in trigonal Se and Te to clarify the uncertainty stemming from the different views on the types of chemical bonding in their crystals and to reconsider the role of valence s- and p-electrons in bonding. The lack of overlapping of the lower and upper bands of valence p-electrons in trigonal Se and the large band separation of valence s- and p-electrons present an opportunity to estimate the contributions of valence s- and p-electrons to the charge densities of two types of bond critical points (BCPs) in trigonal Se. Valence s-electrons and lower p-electrons significantly contribute to the charge density of BCPs of the first type, covalently connecting the nearest neighboring atoms within helical chains. In contrast, the lower and upper valence p-electrons are mainly responsible for the BCPs of the second type linking the neighboring chains in the Se and Te trigonal crystal structures. The nonlocal long-range van der Waals (vdW) correlation functional vdW-DF2, which is important for determining lattice constants, has a minimal effect on BCP parameters, which define the chemical bonding types. The exchange potential of Becke and Johnson modified by Tran and Blaha and the short-range electron–electron correlations considered in the local density approximation correctly reproduce not only the energy bandgap values but also various peculiarities in the electronic band structure of trigonal Se and Te, such as band crossings (Weyl nodes) of the valence p-electrons recently found in trigonal Te via angle-resolved photoemission spectroscopy experiments.
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26

Halley, Scott, John H. Dilles, and Richard M. Tosdal. "Footprints: Hydrothermal Alteration and Geochemical Dispersion Around Porphyry Copper Deposits." SEG Discovery, no. 100 (January 1, 2015): 1–17. http://dx.doi.org/10.5382/segnews.2015-100.fea.

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ABSTRACT Whole-rock lithogeochemical analyses combined with short-wave infrared (SWIR) spectroscopy provide a rapid and cost-effective method for prospecting for porphyry-type hydrothermal systems. Lithogeochemistry detects trace metals to average crustal abundance levels and allows vectoring via gradients of chalcophile and lithophile elements transported by magmatic-hydrothermal ore and external circulating fluids that are dispersed and trapped in altered rocks. Of particular use are alkalis in sericite and metals such as Mo, W, Se, Te, Bi, As, and Sb, which form stable oxides that remain in weathered rocks and soils. SWIR mapping of shifts in the 2,200-nm Al-OH absorption feature in sericite define paleofluid pH gradients useful for vectoring toward the center of the buoyant metal-bearing magmatic-hydrothermal plume.
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27

Leite, Claudia da Costa, Kette Dualibi Ramos Valente, Lia Arno Fiore, and Maria Concepción García Otaduy. "Proton spectroscopy of the thalamus in a homogeneous sample of patients with easy-to-control juvenile myoclonic epilepsy." Radiologia Brasileira 50, no. 5 (October 2017): 279–84. http://dx.doi.org/10.1590/0100-3984.2016.0086.

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Abstract Objective: Juvenile myoclonic epilepsy (JME) is a subtype of genetically determined generalized epilepsy that does not present abnormalities on conventional magnetic resonance imaging. The aim of this study was to identify metabolic alterations in the thalamus in a clinically homogeneous sample of patients with easy-to-control JME, using short-echo time proton magnetic resonance spectroscopy (MRS). Materials and Methods: We performed single-voxel (2 cm × 2 cm × 2 cm), short-echo time (TE = 35 ms) proton MRS of the thalamus in 21 patients with JME and in 14 healthy age-matched controls. We quantified N-acetylaspartate (NAA), total NAA, creatine (Cr), choline, and myo-inositol (MI), as well as the sum of glutamate and glutamine signals, all scaled to internal water content, and we calculated metabolite ratios using Cr as a reference. Values of p < 0.05 were considered significant. Results: The MI level and the MI/Cr ratio were significantly lower in the thalami of patients diagnosed with JME than in those of the controls. Other metabolites and their ratios did not differ significantly between the two groups. Conclusion: In our sample of 21 JME patients, we identified lower levels of MI in the thalamus. No significant abnormalities were observed in the concentrations or ratios of other metabolites.
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Yokoyama, Tetsuya, and Eizo Nakamura. "Precise analysis of the 228Ra/226Ra isotope ratio for short-lived U-series disequilibria in natural samples by total evaporation thermal ionization mass spectrometry (TE-TIMS)." Journal of Analytical Atomic Spectrometry 19, no. 6 (2004): 717. http://dx.doi.org/10.1039/b400829d.

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Wilson, Martin, Nigel P. Davies, Yu Sun, Kal Natarajan, Theodoros N. Arvanitis, Risto A. Kauppinen, and Andrew C. Peet. "A comparison between simulated and experimental basis sets for assessing short-TE in vivo 1 H MRS data at 1.5 T." NMR in Biomedicine 23, no. 10 (October 15, 2010): 1117–26. http://dx.doi.org/10.1002/nbm.1538.

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Boer, V. O., A. L. H. M. W. van Lier, J. M. Hoogduin, J. P. Wijnen, P. R. Luijten, and D. W. J. Klomp. "7-T 1 H MRS with adiabatic refocusing at short TE using radiofrequency focusing with a dual-channel volume transmit coil." NMR in Biomedicine 24, no. 9 (February 4, 2011): 1038–46. http://dx.doi.org/10.1002/nbm.1641.

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Near, Jamie, Jesper Andersson, Eduard Maron, Ralf Mekle, Rolf Gruetter, Philip Cowen, and Peter Jezzard. "Unedited in vivo detection and quantification of γ-aminobutyric acid in the occipital cortex using short-TE MRS at 3 T." NMR in Biomedicine 26, no. 11 (May 22, 2013): 1353–62. http://dx.doi.org/10.1002/nbm.2960.

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32

Cacace, Anthony T., Talin Tasciyan, and Joseph P. Cousins. "Principles of Functional Magnetic Resonance Imaging: Application to Auditory Neuroscience." Journal of the American Academy of Audiology 11, no. 05 (May 2000): 239–72. http://dx.doi.org/10.1055/s-0042-1748052.

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AbstractFunctional imaging based on magnetic resonance methods is a new research frontier for exploring a wide range of central nervous system (CNS) functions, including information processing in sensory, motor, cognitive, and linguistic systems. Being able to localize and study human brain function in vivo, in relatively high resolution and in a noninvasive manner, makes this a technique of unparalleled importance. In order to appreciate and fully understand this area of investigation, a tutorial covering basic aspects of this methodology is presented. We introduce functional magnetic resonance imaging (fMRI) by providing an overview of the studies of different sensory systems in response to modality-specific stimuli, followed by an outline of other areas that have potential clinical relevance to the medical, cognitive, and communicative sciences. The discussion then focuses on the basic principles of magnetic resonance methods including magnetic resonance imaging, MR spectroscopy, fMRI, and the potential role that MR technology may play in understanding a wide range of auditory functions within the CNS, including tinnitus-related activity. Because the content of the material found herein might be unfamiliar to some, we provide a broad range of background and review articles to serve as a technical resource. Abbreviations: AL = anterior lateral, BOLD = blood oxygen level dependent, Cho = choline, CL = caudal lateral, CNS = central nervous system, CR = creatine, EEG = electroencephalography, EPI = echo planar imaging, ER = event related, ETS = echo-time shifting, fMRI = functional magnetic resonance imaging, FOV = field of view, G = Gauss, GET = gaze-evoked tinnitus, GRE = gradient-recalled echo, MEG = magnetoencephalography, ml = myo-inositol, ML = medial lateral, MRI = magnetic resonance imaging, MRS = magnetic resonance spectroscopy, NAA = N-acetylaspartate, NMR = nuclear magnetic resonance, PET = positron emission tomography, PRESTO = principles of echo shifting with a train of observations, RF = radio frequency, ROI = regions of interest, SE = spin echo, STEAM = short-TE stimulated echo acquisition mode, Τ = Tesla, TE = echo time, TR = repetition time
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Kleindienst, Andrea, Christos M. Tolias, Frank D. Corwin, Christian Müller, Anthony Marmarou, Panos Fatouros, and M. Ross Bullock. "Assessment of cerebral S100B levels by proton magnetic resonance spectroscopy after lateral fluid-percussion injury in the rat." Journal of Neurosurgery 102, no. 6 (June 2005): 1115–21. http://dx.doi.org/10.3171/jns.2005.102.6.1115.

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Object. After traumatic brain injury (TBI), S100B protein is released by astrocytes. Furthermore, cerebrospinal fluid (CSF) and serum S100B levels have been correlated to outcome. Given that no data exist about the temporal profile of cerebral S100B levels following TBI and their correlation to serum levels, the authors examined whether proton magnetic resonance (MR) spectroscopy is capable of measuring S100B. Methods. Results of in vitro proton MR spectroscopy experiments (2.35-tesla magnet, 25 G/cm, point-resolved spatially localized spectroscopy) revealed an S100B-specific peak at 4.5 ppm and confirmed a positive correlation between different S100B concentrations (10 nM–1 µM) and the area under the curve (AUC) for the S100B peak (r = 0.991, p < 0.001). Thereafter, proton MR spectroscopy was performed in male Sprague—Dawley rats (7 × 5 × 5—mm voxel in each hemisphere, TR 3000 msec, TE 30 msec, 256 acquisitions). Exogenously increased CSF S100B levels (∼ 200 ng/ml) through the intraventricular infusion of S100B increased the AUC of the S100B peak from 0.06 ± 0.02 to 0.44 ± 0.06 (p < 0.05), whereas serum S100B levels remained normal. Two hours after lateral fluid-percussion injury, serum S100B levels increased to 0.61 ± 0.09 ng/ml (p < 0.01) and rapidly returned to normal levels, whereas the AUC of the S100B peak increased to 0.19 ± 0.04 at 2 hours postinjury and 0.41 ± 0.07 (p < 0.05) on Day 5 postinjury. Conclusions. Proton MR spectroscopy proves a strong correlation between the AUC of the S100B peak and S100B concentrations. Following experimental TBI, serum S100B levels increased for only a very short period, whereas cerebral S100B levels were increased up to Day 5 postinjury. Given that experimental data indicate that S100B is actively released following TBI, proton MR spectroscopy may represent a new tool to identify increased cerebral S100B levels in patients after injury, thus allowing its biological function to be better understood.
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Koch, J. A., C. A. Back, C. Brown, K. Estabrook, B. A. Hammel, S. P. Hatchett, M. H. Key, et al. "Time-resolved X-ray spectroscopy of deeply buried tracer layers as a density and temperature diagnostic for the fast ignitor." Laser and Particle Beams 16, no. 1 (March 1998): 225–32. http://dx.doi.org/10.1017/s0263034600011873.

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The fast ignitor concept for inertial confinement fusion relies on the generation of hot electrons, produced by a short-pulse ultrahigh intensity laser, which propagate through high-density plasma to deposit their energy in the compressed fuel core and heat it to ignition. In preliminary experiments designed to investigate deep heating of high-density matter, we used a 20 joule, 0.5–30 ps laser to heat solid targets, and used emission spectroscopy to measure plasma temperatures and densities achieved at large depths (2–20 microns) away from the initial target surface. The targets consisted of an Al tracer layer buried within a massive CH slab; H-like and He-like line emission was then used to diagnose plasma conditions. We observe spectra from tracer layers buried up to 20 microns deep, measure emission durations of up to 200 ps, measure plasma temperatures up to Te=650 eV, and measure electron densities above 1023 cm−3. Analysis is in progress, but the data are in reasonable agreement with heating simulations when space-charge induced inhibition is included in hot-electron transport, and this supports the conclusion that the deep heating is initiated by hot electrons.
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Choi, Changho, Sandeep Ganji, Keith Hulsey, Akshay Madan, Zoltan Kovacs, Ivan Dimitrov, Song Zhang, et al. "A comparative study of short- and long-TE 1 H MRS at 3 T for in vivo detection of 2-hydroxyglutarate in brain tumors." NMR in Biomedicine 26, no. 10 (April 17, 2013): 1242–50. http://dx.doi.org/10.1002/nbm.2943.

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Xin, Lijing, Bernard Lanz, gxia Lei, and Rolf Gruetter. "Assessment of Metabolic Fluxes in the Mouse Brain in Vivo Using 1H-[13C] NMR Spectroscopy at 14.1 Tesla." Journal of Cerebral Blood Flow & Metabolism 35, no. 5 (January 21, 2015): 759–65. http://dx.doi.org/10.1038/jcbfm.2014.251.

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13C magnetic resonance spectroscopy (MRS) combined with the administration of 13C labeled substrates uniquely allows to measure metabolic fluxes in vivo in the brain of humans and rats. The extension to mouse models may provide exclusive prospect for the investigation of models of human diseases. In the present study, the short-echo-time (TE) full-sensitivity 1H-[13C] MRS sequence combined with high magnetic field (14.1 T) and infusion of [U-13C6] glucose was used to enhance the experimental sensitivity in vivo in the mouse brain and the 13C turnover curves of glutamate C4, glutamine C4, glutamate+glutamine C3, aspartate C2, lactate C3, alanine C3, γ-aminobutyric acid C2, C3 and C4 were obtained. A one-compartment model was used to fit 13C turnover curves and resulted in values of metabolic fluxes including the tricarboxylic acid (TCA) cycle flux VTCA (1.05 ± 0.04 μmol/g per minute), the exchange flux between 2-oxoglutarate and glutamate Vx (0.48 ± 0.02 μmol/g per minute), the glutamate-glutamine exchange rate Vgln (0.20 ± 0.02 μmol/g per minute), the pyruvate dilution factor Kdil (0.82 ± 0.01), and the ratio for the lactate conversion rate and the alanine conversion rate VLac/ VAla (10 ± 2). This study opens the prospect of studying transgenic mouse models of brain pathologies.
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Ara, Anjuman, Zhaojia Wu, Aizhang Xu, Khawaja Ashfaque Ahmed, Scot C. Leary, Md Fahmid Islam, Rajni Chibbar, Yue Wu, and Jim Xiang. "The Critical Role of AMPKα1 in Regulating Autophagy and Mitochondrial Respiration in IL-15-Stimulated mTORC1Weak Signal-Induced T Cell Memory: An Interplay between Yin (AMPKα1) and Yang (mTORC1) Energy Sensors in T Cell Differentiation." International Journal of Molecular Sciences 23, no. 17 (August 23, 2022): 9534. http://dx.doi.org/10.3390/ijms23179534.

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Two common γ-chain family cytokines IL-2 and IL-15 stimulate the same mammalian target of rapamycin complex-1 (mTORC1) signaling yet induce effector T (TE) and memory T (TM) cell differentiation via a poorly understood mechanism(s). Here, we prepared in vitro IL-2-stimulated TE (IL-2/TE) and IL-15-stimulated TM (IL-15/TM) cells for characterization by flow cytometry, Western blotting, confocal microscopy and Seahorse-assay analyses. We demonstrate that IL-2 and IL-15 stimulate strong and weak mTORC1 signals, respectively, which lead to the formation of CD62 ligand (CD62L)− killer cell lectin-like receptor subfamily G member-1 (KLRG)+ IL-2/TE and CD62L+KLRG− IL-15/TM cells with short- and long-term survival following their adoptive transfer into mice. The IL-15/mTORC1Weak signal activates the forkhead box-O-1 (FOXO1), T cell factor-1 (TCF1) and Eomes transcriptional network and the metabolic adenosine monophosphate-activated protein kinase-α-1 (AMPKα1), Unc-51-like autophagy-activating kinase-1 (ULK1) and autophagy-related gene-7 (ATG7) axis, increasing the expression of mitochondrial regulators aquaporin-9 (AQP9), mitochondrial transcription factor-A (TFAM), peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α), carnitine palmitoyl transferase-1 (CPT1α), microtubule-associated protein light chain-3 II (LC3II), Complex I and ortic atrophy-1 (OPA1), leading to promoting mitochondrial biogenesis and fatty-acid oxidation (FAO). Interestingly, AMPKα1 deficiency abrogates these downstream responses to IL-15/mTORC1Weak signaling, leading to the upregulation of mTORC1 and hypoxia-inducible factor-1α (HIF-1α), a metabolic switch from FAO to glycolysis and reduced cell survival. Taken together, our data demonstrate that IL-15/mTORC1Weak signaling controls T-cell memory via activation of the transcriptional FOXO1-TCF1-Eomes and metabolic AMPKα1-ULK1-ATG7 pathways, a finding that may greatly impact the development of efficient vaccines and immunotherapies for the treatment of cancer and infectious diseases.
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Shyu, Claire, Sonja Elsaid, Peter Truong, Sofia Chavez, and Bernard Le Foll. "MR Spectroscopy of the Insula: Within- and between-Session Reproducibility of MEGA-PRESS Measurements of GABA+ and Other Metabolites." Brain Sciences 11, no. 11 (November 19, 2021): 1538. http://dx.doi.org/10.3390/brainsci11111538.

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The insula plays a critical role in many neuropsychological disorders. Research investigating its neurochemistry with magnetic resonance spectroscopy (MRS) has been limited compared with cortical regions. Here, we investigate the within-session and between-session reproducibility of metabolite measurements in the insula on a 3T scanner. We measure N-acetylaspartate + N-acetylaspartylglutamate (tNAA), creatine + phosphocreatine (tCr), glycerophosphocholine + phosphocholine (tCho), myo-inositol (Ins), glutamate + glutamine (Glx), and γ-aminobutyric acid (GABA) in one cohort using a j-edited MEGA-PRESS sequence. We measure tNAA, tCr, tCho, Ins, and Glx in another cohort with a standard short-TE PRESS sequence as a reference for the reproducibility metrics. All participants were scanned 4 times identically: 2 back-to-back scans each day, on 2 days. Preprocessing was done using LCModel and Gannet. Reproducibility was determined using Pearson’s r, intraclass-correlation coefficients (ICC), coefficients of variation (CV%), and Bland–Altman plots. A MEGA-PRESS protocol requiring averaged results over two 6:45-min scans yielded reproducible GABA measurements (CV% = 7.15%). This averaging also yielded reproducibility metrics comparable to those from PRESS for the other metabolites. Voxel placement inconsistencies did not affect reproducibility, and no sex differences were found. The data suggest that MEGA-PRESS can reliably measure standard metabolites and GABA in the insula.
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Gottschalk, Michael, Laurent Lamalle, and Christoph Segebarth. "Short-TE localised1H MRS of the human brain at 3 T: quantification of the metabolite signals using two approaches to account for macromolecular signal contributions." NMR in Biomedicine 21, no. 5 (2008): 507–17. http://dx.doi.org/10.1002/nbm.1219.

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40

Kaae, Anne Christine, Michael C. Kreissl, Marcus Krüger, Manfred Infanger, Daniela Grimm, and Markus Wehland. "Kinase-Inhibitors in Iodine-Refractory Differentiated Thyroid Cancer—Focus on Occurrence, Mechanisms, and Management of Treatment-Related Hypertension." International Journal of Molecular Sciences 22, no. 22 (November 12, 2021): 12217. http://dx.doi.org/10.3390/ijms222212217.

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Differentiated thyroid cancer (DTC) usually has a good prognosis when treated conventionally with thyroidectomy, radioactive iodine (RAI) and thyroid-stimulating hormone suppression, but some tumors develop a resistance to RAI therapy, requiring alternative treatments. Sorafenib, lenvatinib and cabozantinib are multikinase inhibitors (MKIs) approved for the treatment of RAI-refractory DTC. The drugs have been shown to improve progression-free survival (PFS) and overall survival (OS) via the inhibition of different receptor tyrosine kinases (RTKs) that are involved in tumorigenesis and angiogenesis. Both sorafenib and lenvatinib have been approved irrespective of the line of therapy for the treatment of RAI-refractory DTC, whereas cabozantinib has only been approved as a second-line treatment. Adverse effects (AEs) such as hypertension are often seen with MKI treatment, but are generally well manageable. In this review, current clinical studies will be discussed, and the toxicity and safety of sorafenib, lenvatinib and cabozantinib treatment will be evaluated, with a focus on AE hypertension and its treatment options. In short, treatment-emergent hypertension (TE-HTN) occurs with all three drugs, but is usually well manageable and leads only to a few dose modifications or even discontinuations. This is emphasized by the fact that lenvatinib is widely considered the first-line drug of choice, despite its higher rate of TE-HTN.
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Matsusue, Eiji, Chie Inoue, Sadaharu Tabuchi, Hiroki Yoshioka, Yuichiro Nagao, Kensuke Matsumoto, Kazuhiko Nakamura, and Shinya Fujii. "Utility of 3T single-voxel proton MR spectroscopy for differentiating intracranial meningiomas from intracranial enhanced mass lesions." Acta Radiologica Open 10, no. 4 (April 2021): 205846012110094. http://dx.doi.org/10.1177/20584601211009472.

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Background Proton magnetic resonance spectroscopy (MRS) provides structural and metabolic information that is useful for the diagnosis of meningiomas with atypical radiological appearance. However, the metabolite that should be prioritized for the diagnosis of meningiomas has not been established. Purpose To evaluate the differences between the metabolic peaks of meningiomas and other intracranial enhanced mass lesions (non-meningiomas) using MR spectroscopy in short echo time (TE) spectra and the most useful metabolic peak for discriminating between the groups. Material and Methods The study involved 9 meningiomas, 22 non-meningiomas, intracranial enhancing tumors and abscesses, and 15 normal controls. The ranking of the peak at 3.8 ppm, peak at 3.8 ppm/Creatine (Cr), β-γ Glutamine-Glutamate (bgGlx)/Cr, N-acetyl compounds (NACs)/Cr, choline (Cho)/Cr, lipid and/or lactate (Lip-Lac) at 1.3 ppm/Cr, and the presence of alanine (Ala) were derived. The metabolic peaks were compared using the Mann-Whitney U test. ROC analysis was used to determine the cut-off values for differentiating meningiomas from non-meningiomas using statistically significant metabolic peaks. Results The ranking of the peak at 3.8 ppm among all the peaks, peak at 3.8 ppm/Cr, bgGlx/Cr, Lip-Lac/Cr, and the presence of Ala discriminated meningiomas from non-meningiomas with moderate to high accuracy. The highest accuracy was 96.9% at a threshold value of 3 for the rank of the peak at 3.8 ppm. Conclusion A distinct elevated peak at 3.8 ppm, ranked among the top three highest peaks, allowed the detection of meningiomas.
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Ara, Anjuman, Aizhang Xu, Khawaja Ashfaque Ahmed, Scot C. Leary, Md Fahmid Islam, Zhaojia Wu, Rajni Chibbar, and Jim Xiang. "The Energy Sensor AMPKα1 Is Critical in Rapamycin-Inhibition of mTORC1-S6K-Induced T-cell Memory." International Journal of Molecular Sciences 23, no. 1 (December 21, 2021): 37. http://dx.doi.org/10.3390/ijms23010037.

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Energy sensors mTORC1 and AMPKα1 regulate T-cell metabolism and differentiation, while rapamycin (Rapa)-inhibition of mTORC1 (RIM) promotes T-cell memory. However, the underlying pathway and the role of AMPKα1 in Rapa-induced T-cell memory remain elusive. Using genetic and pharmaceutical tools, we demonstrate that Rapa promotes T-cell memory in mice in vivo post Listeria monocytogenesis rLmOVA infection and in vitro transition of effector T (TE) to memory T (TM) cells. IL-2- and IL-2+Rapa-stimulated T [IL-2/T and IL-2(Rapa+)/T] cells, when transferred into mice, differentiate into short-term IL-7R−CD62L−KLRG1+ TE and long-lived IL-7R+CD62L+KLRG1− TM cells, respectively. To assess the underlying pathways, we performed Western blotting, confocal microscopy and Seahorse-assay analyses using IL-2/T and IL-2(Rapa+)/T-cells. We determined that IL-2(Rapa+)/T-cells activate transcription FOXO1, TCF1 and Eomes and metabolic pAMPKα1(T172), pULK1(S555) and ATG7 molecules and promote mitochondrial biogenesis and fatty-acid oxidation (FAO). We found that rapamycin-treated AMPKα-deficient AMPKα1-KO IL-2(Rapa+)/TM cells up-regulate transcription factor HIF-1α and induce a metabolic switch from FAO to glycolysis. Interestingly, despite the rapamycin treatment, AMPKα-deficient TM cells lost their cell survival capacity. Taken together, our data indicate that rapamycin promotes T-cell memory via transcriptional FOXO1-TCF1-Eomes programs and AMPKα1-ULK1-ATG7 metabolic axis, and that AMPKα1 plays a critical role in RIM-induced T-cell memory.
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Knudsen, Marie Krøll, Jamie Near, Anne Bastholm Blicher, Poul Videbech, and Jakob Udby Blicher. "Magnetic resonance (MR) spectroscopic measurement of γ-aminobutyric acid (GABA) in major depression before and after electroconvulsive therapy." Acta Neuropsychiatrica 31, no. 1 (August 6, 2018): 17–26. http://dx.doi.org/10.1017/neu.2018.22.

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AbstractObjectivePrior studies suggest that a dysregulation of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) is involved in the pathophysiology of major depression. We aimed to elucidate changes in cortical GABA content in relation to depression and electroconvulsive therapy (ECT) using magnetic resonance spectroscopy (MRS).MethodsIn total, 11 patients with major depression or depressive episode of bipolar disorder (mean pre-ECT Ham-17 of 26) and 11 healthy subjects were recruited. GABA was quantified using short-TE MRS in prefrontal and occipital cortex. Other neurometabolites such as glutathione (GSH), N-acetylaspartate (NAA) and glutamate (Glu) were secondary outcome measures.ResultsNo significant differences in GABA/Cr levels were observed between patients at baseline and healthy subjects in prefrontal cortex, t(20)=0.089, p=0.93 or occipital cortex t(21)=0.37, p=0.72. All patients improved on Ham-17 (mean post-ECT Ham-17 of 9). No significant difference was found in GABA, Glu, glutamine, choline or GSH between pre- and post-ECT values. However, we observed a significant decrease in NAA levels following ECT t(22)=3.89, p=0.0038, and a significant correlation between the NAA decline and the number of ECT sessions p=0.035.ConclusionsOur study does not support prior studies arguing for GABA as a key factor in the treatment effect of ECT on major depression. The reduction in NAA levels following ECT could be due to neuronal loss or a transient dysfunction in prefrontal cortex. As no long-term follow-up scan was performed, it is unknown whether NAA levels will normalise over time.
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Carotti, Elisa, Federica Carducci, Adriana Canapa, Marco Barucca, Samuele Greco, Marco Gerdol, and Maria Assunta Biscotti. "Transposable Elements and Teleost Migratory Behaviour." International Journal of Molecular Sciences 22, no. 2 (January 9, 2021): 602. http://dx.doi.org/10.3390/ijms22020602.

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Transposable elements (TEs) represent a considerable fraction of eukaryotic genomes, thereby contributing to genome size, chromosomal rearrangements, and to the generation of new coding genes or regulatory elements. An increasing number of works have reported a link between the genomic abundance of TEs and the adaptation to specific environmental conditions. Diadromy represents a fascinating feature of fish, protagonists of migratory routes between marine and freshwater for reproduction. In this work, we investigated the genomes of 24 fish species, including 15 teleosts with a migratory behaviour. The expected higher relative abundance of DNA transposons in ray-finned fish compared with the other fish groups was not confirmed by the analysis of the dataset considered. The relative contribution of different TE types in migratory ray-finned species did not show clear differences between oceanodromous and potamodromous fish. On the contrary, a remarkable relationship between migratory behaviour and the quantitative difference reported for short interspersed nuclear (retro)elements (SINEs) emerged from the comparison between anadromous and catadromous species, independently from their phylogenetic position. This aspect is likely due to the substantial environmental changes faced by diadromous species during their migratory routes.
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Carotti, Elisa, Federica Carducci, Adriana Canapa, Marco Barucca, Samuele Greco, Marco Gerdol, and Maria Assunta Biscotti. "Transposable Elements and Teleost Migratory Behaviour." International Journal of Molecular Sciences 22, no. 2 (January 9, 2021): 602. http://dx.doi.org/10.3390/ijms22020602.

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Transposable elements (TEs) represent a considerable fraction of eukaryotic genomes, thereby contributing to genome size, chromosomal rearrangements, and to the generation of new coding genes or regulatory elements. An increasing number of works have reported a link between the genomic abundance of TEs and the adaptation to specific environmental conditions. Diadromy represents a fascinating feature of fish, protagonists of migratory routes between marine and freshwater for reproduction. In this work, we investigated the genomes of 24 fish species, including 15 teleosts with a migratory behaviour. The expected higher relative abundance of DNA transposons in ray-finned fish compared with the other fish groups was not confirmed by the analysis of the dataset considered. The relative contribution of different TE types in migratory ray-finned species did not show clear differences between oceanodromous and potamodromous fish. On the contrary, a remarkable relationship between migratory behaviour and the quantitative difference reported for short interspersed nuclear (retro)elements (SINEs) emerged from the comparison between anadromous and catadromous species, independently from their phylogenetic position. This aspect is likely due to the substantial environmental changes faced by diadromous species during their migratory routes.
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46

Bunker, Bruce A. "EXAFS Studies of Semiconductor Microstructure." MRS Bulletin 13, no. 2 (February 1988): 36–39. http://dx.doi.org/10.1557/s0883769400066343.

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Extended X-Ray Absorption Fine Structure (EXAFS) is a technique capable of probing local structure in condensed- matter systems, determining distances, coordination numbers, and species of atoms near an x-ray excited atom. Further, this information is obtained separately for each constituent atomic species. EXAFS can be applied equally well to crystals, alloys, or even systems having no long-range order such as liquids, gases, and amorphous materials.Here we review EXAFS spectroscopy and its use in studying semiconductors. First, we show EXAFS in the study of impurities to determine the local environment of Fe implanted in Si. Second, we show how EXAFS can be used to determine local structural distortion in diluted magnetic semiconductors. We next demonstrate that EXAFS can determine the nature of the phase transition in ferroelectric Pb1-x Gex Te, where the transition is revealed to have an order-disorder character in contrast to GeTe where the transition is purely displacive. The theme of these examples is that EXAFS can determine the relative positions of atoms in condensed matter and that the short-range order as determinedn by EXAFS often differs from the long-range order or theoretical expectations.In the EXAFS technique, one measures the x-ray absorption coefficient as a function of x-ray energy. The absorption spectrum shows a number of x-ray edges corresponding to the threshold of excitation of core electrons from the sample's various atomic species. At energies above each of these edges, oscillations in the absorption coefficient are due to backscattering of the photoelectron from the neighboring atoms.
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Walker, Paul, Peggy Provent, Xavier Tizon, Gilles Créhange, Olivier Duchamp, François Brunotte, and Philippe Genne. "In-vivo metabolic characterization of healthy prostate and orthotopic prostate cancer in rats using proton magnetic resonance spectroscopy at 4.7 T." Acta Radiologica 54, no. 1 (February 2013): 121–26. http://dx.doi.org/10.1258/ar.2012.120232.

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Background To assist the development of new anti-cancer drugs, it is important to identify biomarkers of treatment efficacy in the preclinical phases of drug development. In order to improve the predictivity of preclinical experiments, more realistic animal models are needed, for example, tumors xenografted directly on the prostate gland of rodents. Purpose To characterize the in-vivo metabolism of healthy rat prostate and of an orthotopic human prostate cancer model using proton magnetic resonance spectroscopy (MRS). Material and Methods The highly metastatic and hormone-independent PC3-MM2 human prostate cancer model was implanted into the ventral prostate lobe of three Nude rats. Healthy Nude (n = 6) and Sprague-Dawley (n = 6) rats were also studied for interspecies comparison of normal prostate metabolism. Magnetic resonance imaging and short echo-time (TE 11.2 ms) single voxel PRESS spectroscopy were performed on dorsal (DP) and ventral (VP) prostate as well as tumor at 4.7 T. The metabolic content and volume of dorsal and ventral lobes were characterized as a function of species and age. Results Slightly lower total creatine (tCr)/water (11.3±2.6 vs. 15.3±3.0, NS), but significantly higher Inositol (Ins)/water (18.9±1.9 vs. 6.6±3.3, P < 0.003) and total choline (tCho)/water (15.0±2.1 vs. 5.6±1.1, P< 0.00007) were observed within healthy DP lobes with respect to VP lobes. No significant variation in metabolic content was seen in healthy DP and VP lobes of Nude rats as a function of age, and no species dependence was observed in their metabolic content. For the orthotopic PC3-MM2 tumor, implanted in VP, the tCr/water ratio was significantly lower (3.1±0.9) than neighboring DP (12.8±1.8, P < 0.00003) and healthy VP (15.3±3.0, P < 0.00006). For Ins, the metabolite ratio in PC3-MM2 was close to that of healthy VP (4.3±2.8 vs. 6.6±3.3, p = NS), but much lower than in neighboring DP (19.1±1.3, P < 0.00005). A similar trend was also observed for tCho, where metabolite ratios in PC3-MM2, healthy VP and neighboring DP were 3.5±0.9, 5.6±1.1, and 15.9±0.8, respectively. Conclusion The in-vivo MRS study of healthy prostate and orthotopic prostate cancer is feasible in rats. Such baseline data could be important when following the modifications in metabolism, including during anti-cancer drug development protocols or following radiotherapy.
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Kousi, E., I. Tsougos, E. Tsolaki, K. N. Fountas, K. Theodorou, I. Fezoulidis, E. Kapsalaki, and C. Kappas. "Spectroscopic Evaluation of Glioma Grading at 3T: The Combined Role of Short and Long TE." Scientific World Journal 2012 (2012): 1–11. http://dx.doi.org/10.1100/2012/546171.

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Purpose. To evaluate the diagnostic value of 3T1H-MRS in grading cerebral gliomas using short and long echo times.Methods. 1H-MRS was performed on 71 patients with untreated cerebral gliomas. Metabolite ratios of NAA/Cr, Cho/Cr, Cho/NAA, and mI/Cr were calculated for short and long TE and compared between low and high grade gliomas. Lipids were qualitatively evaluated. ROC analysis was performed to obtain the cut-off values for the metabolic ratios presenting statistical difference between the two glioma grades.Results. Intratumoral Cho/Cr at both TEs and long TE Cho/NAA were significantly different between low and high grade gliomas. Peritumoral NAA/Cr of both TEs, as well as long TE Cho/Cr and Cho/NAA ratios, significantly differentiated the two tumor grades. Diagnostic sensitivity of peritumoral short TE NAA/Cr proved to be superior over the other metabolic ratios, whereas intratumoral short TE Cho/Cr reached the highest levels of specificity and accuracy. Overall, short TE 1H-MRS reached higher total sensitivity in predicting glioma grade, over long TE.Conclusion. An advantage was found in using short TE over long TE 1H-MRS in the discrimination of low versus high grade gliomas. Moreover, the results suggested that the peritumoral area of gliomas may be more valuable in predicting glioma grade than using only the intratumoral area.
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49

Price, Emma, Olympia Gianfrancesco, Patrick T. Harrison, Bernhard Frank, Vivien J. Bubb, and John P. Quinn. "CRISPR Deletion of a SVA Retrotransposon Demonstrates Function as a cis-Regulatory Element at the TRPV1/TRPV3 Intergenic Region." International Journal of Molecular Sciences 22, no. 4 (February 15, 2021): 1911. http://dx.doi.org/10.3390/ijms22041911.

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SINE-VNTR-Alu (SVA) retrotransposons are a subclass of transposable elements (TEs) that exist only in primate genomes. TE insertions can be co-opted as cis-regulatory elements (CREs); however, the regulatory potential of SVAs has predominantly been demonstrated using bioinformatic approaches and reporter gene assays. The objective of this study was to demonstrate SVA cis-regulatory activity by CRISPR (clustered regularly interspaced short palindromic repeats) deletion and subsequent measurement of direct effects on local gene expression. We identified a region on chromosome 17 that was enriched with human-specific SVAs. Comparative gene expression analysis at this region revealed co-expression of TRPV1 and TRPV3 in multiple human tissues, which was not observed in mouse, highlighting key regulatory differences between the two species. Furthermore, the intergenic region between TRPV1 and TRPV3 coding sequences contained a human specific SVA insertion located upstream of the TRPV3 promoter and downstream of the 3′ end of TRPV1, highlighting this SVA as a candidate to study its potential cis-regulatory activity on both genes. Firstly, we generated SVA reporter gene constructs and demonstrated their transcriptional regulatory activity in HEK293 cells. We then devised a dual-targeting CRISPR strategy to facilitate the deletion of this entire SVA sequence and generated edited HEK293 clonal cell lines containing homozygous and heterozygous SVA deletions. In edited homozygous ∆SVA clones, we observed a significant decrease in both TRPV1 and TRPV3 mRNA expression, compared to unedited HEK293. In addition, we also observed an increase in the variability of mRNA expression levels in heterozygous ∆SVA clones. Overall, in edited HEK293 with SVA deletions, we observed a disruption to the co-expression of TRPV1 and TRPV3. Here we provide an example of a human specific SVA with cis-regulatory activity in situ, supporting the role of SVA retrotransposons as contributors to species-specific gene expression.
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50

Jackson, Edward F., Timothy J. Doyle, Jerry S. Wolinsky, and Ponnada A. Narayana. "Short TE hydrogen-1 spectroscopic MR imaging of normal human brain: Reproducibility studies." Journal of Magnetic Resonance Imaging 4, no. 4 (July 1994): 545–51. http://dx.doi.org/10.1002/jmri.1880040406.

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