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Liguang Li, Zhenli L He, Malak M Tfaily, Patrick Inglett, Peter J Stoffella
Leaching of dissolved organic nitrogen (DON) has been reported as a pathway of N loss from agriculture, but the molecular composition of DON in agricultural water is poorly understood. Runoff water samples were collected from citrus grove furrows (CGF), ditches (CGD) and pasture ditches (PD) in four seasons. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) was used to investigate molecular composition of DON. Chemodiversity index of DON had spatiotemporal variations, while the molecular composition of total DON showed minimal variations, except for PD in November...
March 16, 2018: Water Research
Bo Yang, Nathan Heath Patterson, Tina Tsui, Richard M Caprioli, Jeremy L Norris
It has been widely recognized that individual cells that exist within a large population of cells, even if they are genetically identical, can have divergent molecular makeups resulting from a variety of factors, including local environmental factors and stochastic processes within each cell. Presently, numerous approaches have been described that permit the resolution of these single-cell expression differences for RNA and protein; however, relatively few techniques exist for the study of lipids and metabolites in this manner...
March 13, 2018: Journal of the American Society for Mass Spectrometry
Agata Tobola-Galus, Jan Swakon, Pawel Olko
The aim of these studies was to investigate depth dose distribution of a 60 MeV proton beam formed by a set of dedicated mesh-formed collimators. The set of mini-beams formed by the mesh is scattered in the tissue and lead to uniform energy deposition in the target volume. The rationale is to protect the eyelid skin from complications after hypofractionated radiation therapy. The experimental verification of the depth dose distribution for collimators of 1-3 mm mesh size was performed in solid state and water phantoms on 60 MeV proton beam from the AIC-144 cyclotron...
February 24, 2018: Radiation Protection Dosimetry
Matthew J O'Hara, Nathaniel J Murray, Jennifer C Carter, Samuel S Morrison
Zirconium-89 (89 Zr), produced by the (p, n) reaction from naturally monoisotopic yttrium (nat Y), is a promising positron emitting isotope for immunoPET imaging. Its long half-life of 78.4 h is sufficient for evaluating slow physiological processes. A prototype automated fluidic system, coupled to on-line and in-line detectors, has been constructed to facilitate development of new89 Zr purification methodologies. The highly reproducible reagent delivery platform and near-real time monitoring of column effluents allows for efficient method optimization...
February 24, 2018: Journal of Chromatography. A
Zhineng Hao, Yongguang Yin, Juan Wang, Dong Cao, Jingfu Liu
There are increasing concerns about the adverse effects of released engineered nanoparticles and photochemically formed organohalogen compounds (OHCs) on human health and the environment. Herein, we report that titanium dioxide nanoparticles (TiO2 NPs) can photocatalytically halogenate dissolved organic matter (DOM) to form a large number of organobromine compounds (OBCs) and organoiodine compounds (OICs), as characterized by negative ion electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry...
March 7, 2018: Science of the Total Environment
Quang Viet Ly, Jin Hur
This study assessed the relative contributions of different constitutes in dissolved organic matter (DOM) with two different sources (i.e., urban river and effluent) to membrane fouling on three types of ultrafiltration (UF) membranes via excitation emission matrix - parallel factor analysis (EEM-PARAFAC), size exclusion chromatography (SEC), and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Two polyethersulfone membranes with different pore sizes and one regenerated cellulose membrane were used as representative hydrophobic (HPO) and hydrophilic (HPI) UF membranes, respectively...
March 1, 2018: Chemosphere
Ségolène De Vaugelade, Edith Nicol, Svetlana Vujovic, Sophie Bourcier, Stéphane Pirnay, Stéphane Bouchonnet
RATIONALE: The present work is devoted to the structural elucidation of by-products issued from the direct UV-visible irradiation of dehydroacetic acid (DHA) in solution and in cosmetic emulsion. METHODS: Analyses were carried out using a gas chromatography coupled with an ion trap mass spectrometer and by a high performance liquid chromatography coupled with ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (LC-UHRMS). The potential toxicities of by-products were estimated by in silico calculations based on a QSAR (Quantitative Structure-Activity Relationship) approach and by in vitro bioassays conducted on Vibrio fischeri bacteria...
March 8, 2018: Rapid Communications in Mass Spectrometry: RCM
Chloé Roullier-Gall, Julie Signoret, Daniel Hemmler, Michael A Witting, Basem Kanawati, Bernhard Schäfer, Régis D Gougeon, Philippe Schmitt-Kopplin
Whisky can be described as a complex matrix integrating the chemical history from the fermented cereals, the wooden barrels, the specific distillery processes, aging, and environmental factors. In this study, using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), we analyzed 150 whisky samples from 49 different distilleries, 7 countries, and ranging from 1 day new make spirit to 43 years of maturation with different types of barrel...
2018: Frontiers in Chemistry
Ning Yang, Krishna D P Anapindi, Stanislav S Rubakhin, Pingli Wei, Qing Yu, Lingjun Li, Paul J Kenny, Jonathan V Sweedler
Conserved across vertebrates, the habenular nuclei are a pair of small symmetrical structures in the epithalamus. The nuclei functionally link the forebrain and midbrain by receiving input from and projecting to several brain regions. Each habenular nucleus comprises two major asymmetrical subnuclei, the medial and lateral habenula. These subnuclei are associated with different physiological processes and disorders, such as depression, nicotine addiction, and encoding aversive stimuli or omitting expected rewarding stimuli...
March 8, 2018: Journal of Proteome Research
Mateusz Adam Synowiecki, Lars Rutger Perk, J Frank W Nijsen
The global network of cyclotrons has expanded rapidly over the last decade. The bulk of its industrial potential is composed of small medical cyclotrons with a proton energy below 20 MeV for radionuclides production. This review focuses on the recent developments of novel medical radionuclides produced by cyclotrons in the energy range of 3 MeV to 20 MeV. The production of the following medical radionuclides will be described based on available literature sources: Tc-99 m, I-123, I-124, Zr-89, Cu-64, Ga-67, Ga-68, In-111, Y-86 and Sc-44...
2018: EJNMMI Radiopharm Chem
Gregory R Naumiec, Lisheng Cai, Shuiyu Lu, Victor W Pike
Positron emission tomography (PET) is an important molecular imaging technique for medical diagnosis, biomedical research and drug development. PET tracers for molecular imaging contain β+ -emitting radionuclides, such as carbon-11 ( t 1/2 = 20.4 min) or fluorine-18 ( t 1/2 = 109.8 min). The [18 F]2-fluoro-pyridyl moiety features in a few prominent PET radiotracers, not least because this moiety is usually resistant to unwanted radiodefluorination in vivo. Various methods have been developed for labeling these radiotracers from cyclotron-produced no-carrier-added [18 F]fluoride ion, mainly based on substitution of a leaving group, such as halide (Cl or Br), or preferably a better leaving group, such as nitro or trimethylammonium...
December 8, 2017: European Journal of Organic Chemistry
Anuj Ram Baitha, Ashwani Kumar, Sudeep Bhattacharjee
We report a table top experiment to investigate production and properties of a plasma confined by a dipole magnet. A water cooled, strong, cylindrical permanent magnet (NdFeB) magnetized along the axial direction and having a surface magnetic field of ∼0.5 T is employed to create a dipole magnetic field. The plasma is created by electron cyclotron resonance heating. Visual observations of the plasma indicate that radiation belts appear due to trapped particles, similar to the earth's magnetosphere. The electron temperature lies in the range 2-13 eV and is hotter near the magnets and in a downstream region...
February 2018: Review of Scientific Instruments
F Arnold, M Naumann, Th Lühmann, A P Mackenzie, E Hassinger
Torque magnetometry is a key method to measure the magnetic anisotropy and quantum oscillations in metals. In order to resolve quantum oscillations in sub-millimeter sized samples, piezo-electric micro-cantilevers were introduced. In the case of strongly correlated metals with large Fermi surfaces and high cyclotron masses, magnetic torque resolving powers in excess of 104 are required at temperatures well below 1 K and magnetic fields beyond 10 T. Here, we present a new broadband read-out scheme for piezo-electric micro-cantilevers via Wheatstone-type resistance measurements in magnetic fields up to 15 T and temperatures down to 200 mK...
February 2018: Review of Scientific Instruments
H Shirvani, S Jafari
The quantum regime of a plasma-whistler-wave-pumped free-electron laser (FEL) in the presence of an axial-guide magnetic field is presented. By quantizing both the plasma whistler field and axial magnetic field, an N-particle three-dimensional Hamiltonian of quantum-FEL (QFEL) has been derived. Employing Heisenberg evolution equations and introducing a new collective operator which controls the vertical motion of electrons, a quantum dispersion relation of the plasma whistler wiggler has been obtained analytically...
March 1, 2018: Journal of Synchrotron Radiation
Miao Hu, Linzhou Zhang, Shan He, Chunming Xu, Quan Shi
RATIONALE: Collision cross section (CCS) is an important shape parameter which is often used in molecular structure investigation. In Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), CCS affects ion signal damping shape due to the effect of ion-neutral collision. It is potential to obtain ion CCS value from FT-ICR MS with the help of proper ion-collision model. METHODS: We have developed a rapid method to obtain the ion damping profile and CCS for mixtures by only one FT-ICR MS measurement...
February 27, 2018: Rapid Communications in Mass Spectrometry: RCM
Pouyan Jahangiri, D Mark Martinez, Cornelia Hoehr
Transient behavior of proton-beam bombarded liquid-targets are studied at various initial conditions at the TR13 cyclotron at TRIUMF. Depending on the initial condition, experiments show a range of different responses from steady-state to self-sustained oscillations. To address this, a system of equations based on the conservation of mass and energy is proposed. Coupling between the beam and fluid-density and chemical reactions driven by the beam (radiolysis) are identified as the main reasons to describe this behavior...
February 2, 2018: Applied Radiation and Isotopes
N H Siboni, J Schluck, K Pierz, H W Schumacher, D Kazazis, J Horbach, T Heinzel
Magnetotransport measurements in combination with molecular dynamics simulations on two-dimensional disordered Lorentz gases in the classical regime are reported. In quantitative agreement between experiment and simulation, the magnetoconductivity displays a pronounced peak as a function of the perpendicular magnetic field B which cannot be explained by existing kinetic theories. This peak is linked to the onset of a directed motion of the electrons along the contour of the disordered obstacle matrix when the cyclotron radius becomes smaller than the size of the obstacles...
February 2, 2018: Physical Review Letters
Alexander J Kim, Sankha Basu, Carolyn Glass, Edgar L Ross, Nathalie Agar, Qing He, David Calligaris
Opioids are often used for analgesia via continuous intrathecal delivery by implantable devices. Higher concentration and daily dose of opioid have been postulated as risk factors for intrathecal granuloma formation. We present a 42-year-old female patient with chronic abdominal pain from refractory pancreatitis, with an intrathecal drug delivery device implanted 21 years prior, delivering continuous intrathecal morphine. After many years without concerning physical signs or complaint, with gradual increases in daily morphine dose, she presented with rapidly progressive neurologic deficits, including lower extremity, bladder, and bowel symptoms...
February 26, 2018: Pain Practice: the Official Journal of World Institute of Pain
Alexey S Kononikhin, Victoria A Sergeeva, Anna E Bugrova, Maria I Indeykina, Natalia L Starodubtseva, Vitaliy V Chagovets, Igor A Popov, Vladimir E Frankevich, Patrick Pedrioli, Gennady T Sukhikh, Eugene N Nikolaev
Urine is a sample of choice for noninvasive biomarkers search because it is easily available in large amounts and its molecular composition provides information on processes in the organism. The high potential of urine peptidomics has been demonstrated for clinical purpose. Several mass spectrometry based approaches have been successfully applied for urine peptidome analysis and potential biomarkers search. Summarizing literature data and our own experience we developed a protocol for comprehensive urine peptidome analysis...
2018: Methods in Molecular Biology
Minkyung Jung, Kenji Yoshida, Kidong Park, Xiao-Xiao Zhang, Can Yesilyurt, Zhuo Bin Siu, Mansoor Bin Abdul Jalil, Jinwan Park, Jeunghee Park, Naoto Nagaosa, Jungpil Seo, Kazuhiko Hirakawa
We demonstrate quantum dot (QD) formation in three-dimensional Dirac semimetal Cd3 As2 nanowires using two electrostatically tuned p-n junctions with a gate and magnetic fields. The linear conductance measured as a function of gate voltage under high magnetic fields is strongly suppressed at the Dirac point close to zero conductance, showing strong conductance oscillations. Remarkably, in this regime, the Cd3 As2 nanowire device exhibits Coulomb diamond features, indicating that a clean single QD forms in the Dirac semimetal nanowire...
February 23, 2018: Nano Letters
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