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https://www.readbyqxmd.com/read/28741297/maldi-ft-icr-ms-for-archaeological-lipid-residue-analysis
#1
Ester Oras, Signe Vahur, Sven Isaksson, Ivari Kaljurand, Ivo Leito
Soft-ionization methods are currently at the forefront of developing novel methods for analysing degraded archaeological organic residues. Here we present little-used soft ionisation method of matrix assisted laser desorption/ionization - Fourier transform - ion cyclotron resonance - mass spectrometry (MALDI-FT-ICR-MS) for the identification of archaeological lipid residues. It is a high-resolution and sensitive method with low limits of detection capable of identifying lipid compounds in small concentrations, thus providing a highly potential new technique for the analysis of degraded lipid components...
July 24, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28738250/optimization-of-beam-dump-shielding-for-k-130-cyclotron-at-vecc
#2
S Chatterjee, K Banerjee, Deepak Pandit, Pratap Roy, T Bandyopadhyay, R Ravishankar, C Bhattacharya, S Bhattacharya, D Datta, S R Banerjee
A compact and efficient beam dump shield has been designed using Monte Carlo simulation code FLUKA to facilitate low background measurement of neutron and gamma rays using K130 cyclotron at Variable Energy Cyclotron Centre, Kolkata (VECC). Iron, lead and high density Polyethylene (HDPE) were considered in the design of the beam dump shield. Representative FLUKA simulation results have been validated using in-beam experiment performed on the same beam dump constituents. Experimental neutron and gamma-rays energy spectra have been found to be in fair agreement with the simulation results...
July 14, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28735113/characterisation-of-the-secondary-neutron-field-generated-by-a-compact-pet-cyclotron-with-mcnp6-and-experimental-measurements
#3
D Alloni, M Prata
The production of the most common used PET radioisotope Fluorine-18 with commercial cyclotrons is obtained from the (18)O(p,n)(18)F nuclear reaction when (18)O-enriched water is bombarded with a proton beam. We present the characterization of the secondary neutron field spectra produced by this reaction in different locations around the cyclotron, through a comparison between MCNP6 Monte Carlo simulation results and experimental data obtained with Neutron Activation Analysis (NAA) of thin target foils of different materials...
July 17, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28734194/high-yield-one-pot-production-of-18-f-fch-via-a-modified-tracerlab-fxfn-module
#4
Ya-Yao Huang, Chia-Ling Tsai, Hsiang-Ping Wen, Kai-Yuan Tzen, Ruoh-Fen Yen, Chyng-Yann Shiue
INTRODUCTION: [(18)F]Fluoromethylcholine ([(18)F]FCH) is a potent tumors imaging agent. In order to fulfill the demand of pre-clinical and clinical studies, we have developed an automated high yield one-pot synthesis of this potent tumors imaging agent. METHODS: [(18)F]FCH was synthesized using a modified TRACERlab FxFN module. Briefly, dibromomethane (10% in CH3CN) was fluorinated with K[(18)F]/K 2.2.2 in a glassy carbon reaction vessel at 120°C for about 5min to generate [(18)F]fluorobromomethane ([(18)F]FBM)...
July 15, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28733966/quantitative-collision-cross-sections-from-fticr-linewidth-measurements-improvements-in-theory-and-experiment
#5
Anupriya, Elaura Gustafson, Daniel N Mortensen, David V Dearden
Two corrections to the equation used in the cross-sectional areas by Fourier transform ion cyclotron resonance ("CRAFTI") technique are identified. In CRAFTI, ion collision cross-sections are obtained from the pressure-dependent ion linewidths in Fourier transform mass spectra. The effects of these corrections on the accuracy of the cross-sections obtained using the CRAFTI technique are evaluated experimentally using the 20 biogenic amino acids and several crown ether complexes with protonated alkyl monoamines...
July 21, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28733661/helical-phase-structure-of-radiation-from-an-electron-in-circular-motion
#6
M Katoh, M Fujimoto, N S Mirian, T Konomi, Y Taira, T Kaneyasu, M Hosaka, N Yamamoto, A Mochihashi, Y Takashima, K Kuroda, A Miyamoto, K Miyamoto, S Sasaki
We theoretically show that a single free electron in circular motion radiates an electromagnetic wave possessing helical phase structure, which is closely related to orbital angular momentum carried by it. We experimentally demonstrate it by interference and double-slit diffraction experiments on radiation from relativistic electrons in spiral motion. Our results indicate that photons carrying orbital angular momentum should be created naturally by cyclotron/synchrotron radiations or Compton scatterings in various situations in cosmic space...
July 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28722690/terahertz-magnetoplasmon-polaritons-with-nonlocal-corrections-for-lossy-two-dimensional-electron-gas-in-gan-based-heterostructures
#7
Lei Cao, Qiang Fu, Bang Wu, Yongqian Xiong
The high electron concentration in GaN-based heterostructures necessitate the consideration of nonlocal corrections in the magnetoconductivity for the study of magnetoplasmon-polaritons (MPPs) in the lossy two dimensional electron gas (2DEG) system with grating couplers. With the complete set of Maxwell equations, the complex dispersion frequency and absorption spectrum are calculated numerically at different magnetic field (B<sub>max</sub> = 10 T) and plasmon wavevectors (k<sub>max</sub> = 5×10<sup>7</sup> m<sup>-1</sup>)...
July 19, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28721671/front-end-electron-transfer-dissociation-coupled-to-a-21-tesla-ft-icr-mass-spectrometer-for-intact-protein-sequence-analysis
#8
Chad R Weisbrod, Nathan K Kaiser, John E P Syka, Lee Early, Christopher Mullen, Jean-Jacques Dunyach, A Michelle English, Lissa C Anderson, Greg T Blakney, Jeffrey Shabanowitz, Christopher L Hendrickson, Alan G Marshall, Donald F Hunt
High resolution mass spectrometry is a key technology for in-depth protein characterization. High-field Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) enables high-level interrogation of intact proteins in the most detail to date. However, an appropriate complement of fragmentation technologies must be paired with FTMS to provide comprehensive sequence coverage, as well as characterization of sequence variants, and post-translational modifications. Here we describe the integration of front-end electron transfer dissociation (FETD) with a custom-built 21 tesla FT-ICR mass spectrometer, which yields unprecedented sequence coverage for proteins ranging from 2...
July 18, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28721647/rubidium-82-pet-imaging-is-feasible-in-a-rat-myocardial-infarction-model
#9
Adam Ali Ghotbi, Andreas Clemmensen, Kasper Kyhl, Bjarke Follin, Philip Hasbak, Thomas Engstrøm, Rasmus Sejersten Ripa, Andreas Kjaer
BACKGROUND: Small-animal myocardial infarct models are frequently used in the assessment of new cardioprotective strategies. A validated quantification of perfusion using a non-cyclotron-dependent PET tracer would be of importance in monitoring response to therapy. We tested whether myocardial PET perfusion imaging is feasible with Rubidium-82 ((82)Rb) in a small-animal scanner using a rat myocardial infarct model. METHODS: 18 Sprague-Dawley rats underwent permanent coronary artery ligation (infarct group), and 11 rats underwent ischemia-reperfusion (reperfusion group) procedure...
July 18, 2017: Journal of Nuclear Cardiology: Official Publication of the American Society of Nuclear Cardiology
https://www.readbyqxmd.com/read/28719191/relationships-between-dissolved-organic-matter-composition-and-photochemistry-in-lakes-of-diverse-trophic-status
#10
Andrew Chapin Maizel, Jing Li, Christina K Remucal
The North Temperate Lakes-Long Term Ecological Research site includes seven lakes in northern Wisconsin that vary in hydrology, trophic status, and landscape position. We examine the molecular composition of dissolved organic matter (DOM) within these lakes using Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) and quantify DOM photochemical activity using probe compounds. Correlations between the relative intensity of individual molecular formulas and reactive species production demonstrate the influence of DOM composition on photochemistry...
July 18, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28707924/suppression-of-alfv%C3%A3-n-modes-on-the-national-spherical-torus-experiment-upgrade-with-outboard-beam-injection
#11
E D Fredrickson, E V Belova, D J Battaglia, R E Bell, N A Crocker, D S Darrow, A Diallo, S P Gerhardt, N N Gorelenkov, B P LeBlanc, M Podestà, Nstx-U Team
In this Letter we present data from experiments on the National Spherical Torus Experiment Upgrade, where it is shown for the first time that small amounts of high pitch-angle beam ions can strongly suppress the counterpropagating global Alfvén eigenmodes (GAE). GAE have been implicated in the redistribution of fast ions and modification of the electron power balance in previous experiments on NSTX. The ability to predict the stability of Alfvén modes, and developing methods to control them, is important for fusion reactors like the International Tokamak Experimental Reactor, which are heated by a large population of nonthermal, super-Alfvénic ions consisting of fusion generated α's and beam ions injected for current profile control...
June 30, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28706067/high-temperature-quantum-oscillations-caused-by-recurring-bloch-states-in-graphene-superlattices
#12
R Krishna Kumar, X Chen, G H Auton, A Mishchenko, D A Bandurin, S V Morozov, Y Cao, E Khestanova, M Ben Shalom, A V Kretinin, K S Novoselov, L Eaves, I V Grigorieva, L A Ponomarenko, V I Fal'ko, A K Geim
Cyclotron motion of charge carriers in metals and semiconductors leads to Landau quantization and magneto-oscillatory behavior in their properties. Cryogenic temperatures are usually required to observe these oscillations. We show that graphene superlattices support a different type of quantum oscillation that does not rely on Landau quantization. The oscillations are extremely robust and persist well above room temperature in magnetic fields of only a few tesla. We attribute this phenomenon to repetitive changes in the electronic structure of superlattices such that charge carriers experience effectively no magnetic field at simple fractions of the flux quantum per superlattice unit cell...
July 14, 2017: Science
https://www.readbyqxmd.com/read/28702664/fast-and-cost-effective-cyclotron-production-of-61-cu-using-a-nat-zn-liquid-target-an-opportunity-for-radiopharmaceutical-production-and-r-d
#13
S J C do Carmo, V H P Alves, F Alves, A J Abrunhosa
Following our previous work on the production of radiometals, such as (64)Cu and (68)Ga, through the irradiation of liquid targets using a medical cyclotron, we describe in this paper a technique to produce (61)Cu through the irradiation of natural zinc using a liquid target. The proposed method is very cost-effective, as it avoids the use of expensive enriched material, and is fast, as a purified solution of (61)CuCl2 is obtained in less than 30 min after the end of beam. Considering its moderate half-life of 3...
July 13, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28699753/identification-of-anthocyanins-from-four-kinds-of-berries-and-their-inhibition-activity-to-%C3%AE-glycosidase-and-protein-tyrosine-phosphatase-1b-by-hplc-ft-icr-ms-ms
#14
Ting Xiao, Zhenghong Guo, Baoshan Sun, Yuqing Zhao
The polyphenolic profiles of four berries (blueberry, bilberry, mulberry, and cranberry) in China were investigated using Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS). Thirty-nine polyphenols including 26 anthocyanins, 9 flavonoids, and 4 phenolic acids were identified accurately. Cyanidin aglycones are common in four berries, and malvidin aglycones are the main compounds found in bilberry and cranberry. The anthocyanin level in blueberry are the highest with 739.6 ± 17.14 mg/g DW and presented the strongest antioxidant capacity in DPPH, ABTS, FRAP, and ORAC assay...
July 12, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28698592/monitoring-changes-of-docosahexaenoic-acid-containing-lipids-during-the-recovery-process-of-traumatic-brain-injury-in-rat-using-mass-spectrometry-imaging
#15
Shuai Guo, Dan Zhou, Mo Zhang, Tiejun Li, Yujie Liu, Yupin Xu, Tianjing Chen, Zhili Li
Brain lipid homoeostasis is critical during recovery process after traumatic brain injury (TBI). In this study, we integrated liquid extraction and electrosonic spray ionization technology to develop an ionization device coupled with a Fourier transform ion cyclotron resonance mass spectrometer for imaging of docosahexaenoic acid (DHA)-containing lipids on rat brain tissues. The ion images of the brain tissue sections from the normal rats and the rats after TBI at acute phase (0 and 1 day) and chronic phase (3, 5, and 7 days) were obtained...
July 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28697482/a-new-approach-for-evaluating-transformations-of-dissolved-organic-matter-dom-via-high-resolution-mass-spectrometry-and-relating-it-to-bacterial-activity
#16
Norbert Kamjunke, Wolf von Tümpling, Norbert Hertkorn, Mourad Harir, Philippe Schmitt-Kopplin, Helge Norf, Markus Weitere, Peter Herzsprung
Streams are important sites of transformation of dissolved organic matter (DOM). The molecular characterization of DOM-quality changes requires sophisticated analytical evaluation techniques. The goal of our study was to link molecular DOM transformation with bacterial activity. We measured the degradation of leaf leachate over a gradient of bacterial production obtained by different rates of percolation of sediments in seven experimental flumes on five sampling dates. We developed a new strategy for evaluating molecular formula data sets obtained by ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS), in which the time-dependent change of component abundance was fitted by a linear regression model after normalization of mass peak intensities...
July 5, 2017: Water Research
https://www.readbyqxmd.com/read/28695407/nuclear-cardiology-in-china-2017
#17
Gongshun Tang
This paper provides the current state of nuclear cardiology in China and contrasts it with the state of nuclear cardiology in the United States (US). The West China Hospital and New York-Presbyterian Hospital (NYPH) were used as representative hospitals to contrast nuclear cardiology in China and the US, respectively. In 2015, there were 101 medical cyclotrons, 774 SPECT or SPECT/CT, 240 PET/CT, and 6 PET/MR cameras in China. Most (~90%) of the nuclear cardiology studies are gated SPECT myocardial perfusion imaging (MPI), and ~10% are other types of studies including MUGA, PET/CT MPI, and viability studies...
July 10, 2017: Journal of Nuclear Cardiology: Official Publication of the American Society of Nuclear Cardiology
https://www.readbyqxmd.com/read/28686409/structural-characterization-of-bio-functionalized-gold-nanoparticles-by-ultrahigh-resolution-mass-spectrometry
#18
Simone Nicolardi, Yuri E M van der Burgt, Jeroen D C Codée, Manfred Wuhrer, Cornelis H Hokke, Fabrizio Chiodo
Bio-functionalized gold nanoparticles (AuNPs) enable innovative translational research and development in biomedicine. Biomolecules such as peptides, proteins, lipids and carbohydrates can be assembled onto AuNPs to yield nanomaterials with unique properties for applications in imaging, photothermal therapy, vaccination strategies and drug delivery. The characterization of functionalized AuNPs still remains an analytical challenge that normally requires the combination of multiple techniques. Laser desorption/ionization (LDI) and matrix-assisted LDI (MALDI) has been applied successfully in combination with time-of-flight (TOF) mass spectrometry (MS) for the analysis of surface chemistry of AuNPs functionalized with synthetic ligands, however only for ligands with a molecular mass limited to 1000 Da...
July 7, 2017: ACS Nano
https://www.readbyqxmd.com/read/28680691/some-aspects-of-an-induced-electric-dipole-moment-in-rotating-and-non-rotating-frames
#19
Abinael B Oliveira, Knut Bakke
Quantum effects on a neutral particle (atom or molecule) with an induced electric dipole moment are investigated when it is subject to the Kratzer potential and a scalar potential proportional to the radial distance. In addition, this neutral is placed in a region with electric and magnetic fields. This system is analysed in both non-rotating and rotating reference frames. Then, it is shown that bound state solutions to the Schrödinger equation can be achieved and, in the search for polynomial solutions to the radial wave function, a restriction on the values of the cyclotron frequency is analysed in both reference frames...
June 2017: Royal Society Open Science
https://www.readbyqxmd.com/read/28667954/radioactive-ion-beams-of-111-in-using-ecr-plasma-sputtering-method
#20
Vaishali Naik, Mahuwa Bhattacharjee, D Lavanya Kumar, Prasanta Karmakar, S K Das, Debashis Banerjee, Sankha Chattopadhyay, Luna Barua, Sujata Saha Das, Asit Kumar Pal, Arup Bandyopadhyay, Alok Chakrabarti
Radioactive ion beams of (111)In (indium-111, half-life 2.8 days) have been produced using the plasma sputtering method in an electron cyclotron resonance (ECR) ion source at the Variable Energy Cyclotron Centre RIB facility. Indium isotopes were first produced by bombarding a natural silver target with a 32 MeV, 40 μA alpha particle beam from the K-130 cyclotron. After radio-chemical separation, about 25 mCi In-chloride was deposited on an aluminum electrode and inserted in the plasma chamber of the ECR. Indium ions produced by ion induced sputtering in the plasma were extracted from the ion source, isotopically separated, and a pure (111)In beam was measured at the focal plane of the separator...
June 2017: Review of Scientific Instruments
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