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https://www.readbyqxmd.com/read/28645021/development-a-validated-highly-sensitive-lc-ms-ms-method-for-simultaneous-quantification-of-ledipasvir-sofosbuvir-and-its-major-metabolite-gs-331007-in-human-plasma-application-to-a-human-pharmacokinetic-study
#1
Ola M Abdallah, Ahmed M Abdel-Megied, Amira S Gouda
A highly sensitive and rapid LC-MS/MS method was developed, fully optimized and validated for the simultaneous determination of Ledipasvir (LED) and Sofosbuvir (SOF) in the presence of its major metabolite GS-331007 in human plasma using Daclatasvir as internal standard (IS). The extraction of analytes and IS from plasma was performed using liquid-liquid extraction with ethyl acetate. The chromatographic separation of these prepared samples was achieved on Xterra MS C8 column (4.6×50mm,5μm) using gradient elution with a mobile phase of ammonium formate buffer (pH 3...
June 20, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28644981/chemical-profiling-and-antioxidant-evaluation-of-yangxinshi-tablet-by-hplc-esi-q-tof-ms-ms-combined-with-dpph-assay
#2
Junfeng Zhu, Xiaojiao Yi, Jinghui Zhang, Shuqing Chen, Yongjiang Wu
Yangxinshi Tablet (YXST) is a Chinese patent medicine commonly used to treat cardiovascular diseases. However, its detailed chemical basis and mechanisms of action have not been clarified. In this study, high performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (HPLC-ESI-Q-TOF-MS) was applied for comprehensive analysis of the chemical constituents in YXST. A total of 127 compounds, including 19 phenolic acids, 12 alkaloids, 51 flavanoids, 32 triterpenoids, 2 lignans, 2 phenylethanoid glycosides, 2 anthraquinones, 1 coumarin, and 6 other compounds, were identified or tentatively deduced by comparing their retention times and MS spectra with those of authentic standards or literature data...
June 15, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/28644644/highly-nuclear-spin-polarized-deuterium-atoms-from-the-uv-photodissociation-of-deuterium-iodide
#3
Dimitris Sofikitis, Pavle Glodic, Greta Koumarianou, Hongyan Jiang, Lykourgos Bougas, Peter C Samartzis, Alexander Andreev, T Peter Rakitzis
We report a novel highly spin-polarized deuterium (SPD) source, via the photodissociation of deuterium iodide at 270 nm. I(^{2}P_{3/2}) photofragments are ionized with m-state selectivity, and their velocity distribution measured via velocity-map slice imaging, from which the D polarization is determined. The process produces ∼100% electronically polarized D at the time of dissociation, which is then converted to ∼60% nuclear D polarization after ∼1.6  ns. These production times for SPD allow collision-limited densities of ∼10^{18}  cm^{-3} and at production rates of ∼10^{21}  s^{-1} which are 10^{6} and 10^{4} times higher than conventional (Stern-Gerlach separation) methods, respectively...
June 9, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28644635/fundamental-transitions-and-ionization-energies-of-the-hydrogen-molecular-ions-with-few-ppt-uncertainty
#4
Vladimir I Korobov, L Hilico, J-Ph Karr
We calculate ionization energies and fundamental vibrational transitions for H_{2}^{+}, D_{2}^{+}, and HD^{+} molecular ions. The nonrelativistic quantum electrodynamics expansion for the energy in terms of the fine structure constant α is used. Previous calculations of orders mα^{6} and mα^{7} are improved by including second-order contributions due to the vibrational motion of nuclei. Furthermore, we evaluate the largest corrections at the order mα^{8}. That allows us to reduce the fractional uncertainty to the level of 7...
June 9, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28644613/impact-of-thermal-decomposition-on-thermal-desorption-instruments-advantage-of-thermogram-analysis-for-quantifying-volatility-distributions-of-organic-species
#5
Harald Stark, Reddy L N Yatavelli, Samantha L Thompson, Hyungu Kang, Jordan Edward Krechmer, Joel R Kimmel, Brett B Palm, Weiwei Hu, Patrick L Hayes, Douglas A Day, Pedro Campuzano-Jost, Manjula R Canagaratna, John T Jayne, Douglas R Worsnop, Jose L Jimenez
We present results from a high-resolution chemical ionization time-of-flight mass spectrometer (HRToF-CIMS), operated with two different thermal desorption inlets, designed to characterize the gas and aerosol composition. Data from two field campaigns at forested sites are shown. Particle volatility distributions are estimated using three different methods: thermograms, elemental formulas, and measured partitioning. Thermogram-based results are consistent with those from an aerosol mass spectrometer (AMS) with a thermal denuder, implying that thermal desorption is reproducible across very different experimental setups...
June 23, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28644563/gas-phase-dissociation-study-of-erythrinian-alkaloids-by-electrospray-ionization-mass-spectrometry-and-computational-methods
#6
T Guaratini, L G P Feitosa, D B Silva, N P Lopes, J L C Lopes, R Vessecchi
Alkaloids from plants of the genus Erythrina display important biological activities, including anxiolytic action. Characterization of these alkaloids by mass spectrometry (MS) has contributed to the construction of a spectral library, has improved understanding of their structures, and has supported the proposal of fragmentation mechanisms in light of density functional calculations (DFT). In this study, we have used low- and high-resolution MS(n) analyses to investigate the fragmentation patterns of erythrinian alkaloids; we have employed the B3LYP/6-31+G(d,p) model to obtain their reactive sites...
June 23, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28644468/observation-of-electron-transfer-mediated-decay-in-aqueous-solution
#7
Isaak Unger, Robert Seidel, Stephan Thürmer, Marvin N Pohl, Emad F Aziz, Lorenz S Cederbaum, Eva Muchová, Petr Slavíček, Bernd Winter, Nikolai V Kryzhevoi
Photoionization is at the heart of X-ray photoelectron spectroscopy (XPS), which gives access to important information on a sample's local chemical environment. Local and non-local electronic decay after photoionization-in which the refilling of core holes results in electron emission from either the initially ionized species or a neighbour, respectively-have been well studied. However, electron-transfer-mediated decay (ETMD), which involves the refilling of a core hole by an electron from a neighbouring species, has not yet been observed in condensed phase...
July 2017: Nature Chemistry
https://www.readbyqxmd.com/read/28644375/gaden-a-3d-gas-dispersion-simulator-for-mobile-robot-olfaction-in-realistic-environments
#8
Javier Monroy, Victor Hernandez-Bennets, Han Fan, Achim Lilienthal, Javier Gonzalez-Jimenez
This work presents a simulation framework developed under the widely used Robot Operating System (ROS) to enable the validation of robotics systems and gas sensing algorithms under realistic environments. The framework is rooted in the principles of computational fluid dynamics and filament dispersion theory, modeling wind flow and gas dispersion in 3D real-world scenarios (i.e., accounting for walls, furniture, etc.). Moreover, it integrates the simulation of different environmental sensors, such as metal oxide gas sensors, photo ionization detectors, or anemometers...
June 23, 2017: Sensors
https://www.readbyqxmd.com/read/28643835/interaction-of-molecular-nitrogen-with-free-electron-laser-radiation
#9
H I B Banks, D A Little, J Tennyson, A Emmanouilidou
We compute molecular continuum orbitals in the single center expansion scheme. We then employ these orbitals to obtain molecular Auger rates and single-photon ionization cross sections to study the interaction of N2 with Free-Electron-Laser (FEL) pulses. The nuclei are kept fixed. We formulate rate equations for the energetically allowed molecular and atomic transitions and we account for dissociation through additional terms in the rate equations. Solving these equations for different parameters of the FEL pulse, allows us to identify the most efficient parameters of the FEL pulse for obtaining the highest contribution of double core hole states (DCH) in the final atomic ion fragments...
June 23, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28643771/dynamics-of-valence-shell-electrons-and-nuclei-probed-by-strong-field-holography-and-rescattering
#10
Samuel G Walt, Niraghatam Bhargava Ram, Marcos Atala, Nikolay I Shvetsov-Shilovski, Aaron von Conta, Denitsa Baykusheva, Manfred Lein, Hans Jakob Wörner
Strong-field photoelectron holography and laser-induced electron diffraction (LIED) are two powerful emerging methods for probing the ultrafast dynamics of molecules. However, both of them have remained restricted to static systems and to nuclear dynamics induced by strong-field ionization. Here we extend these promising methods to image purely electronic valence-shell dynamics in molecules using photoelectron holography. In the same experiment, we use LIED and photoelectron holography simultaneously, to observe coupled electronic-rotational dynamics taking place on similar timescales...
June 15, 2017: Nature Communications
https://www.readbyqxmd.com/read/28643752/dosimetric-characterization-of-optically-stimulated-luminescence-dosimeter-with-therapeutic-photon-beams-for-use-in-clinical-radiotherapy-measurements
#11
Retna Ponmalar, Ravikumar Manickam, K M Ganesh, Sathiyan Saminathan, Arun Raman, Henry Finlay Godson
AIM: The modern radiotherapy techniques impose new challenges for dosimetry systems with high precision and accuracy in in vivo and in phantom dosimetric measurements. The knowledge of the basic characterization of a dosimetric system before patient dose verification is crucial. This incites the investigation of the potential use of nanoDot optically stimulated luminescence dosimeter (OSLD) for application in radiotherapy with therapeutic photon beams. MATERIALS AND METHODS: Measurements were carried out with nanoDot OSLDs to evaluate the dosimetric characteristics such as dose linearity, dependency on field size, dose rate, energy and source-to-surface distance (SSD), reproducibility, fading effect, reader stability, and signal depletion per read out with cobalt-60 (60 Co) beam, 6 and 18 MV therapeutic photon beams...
April 2017: Journal of Cancer Research and Therapeutics
https://www.readbyqxmd.com/read/28643493/identification-of-viridans-streptococci-with-matrix-assisted-laser-desorption-ionization-time-of-flight-mass-spectrometry-by-an-in-house-method-and-a-commercially-available-system
#12
Catalina Suzana Stingu, Klaus Eschrich, Juliane Thiel, Toralf Borgmann, Reiner Schaumann, Arne C Rodloff
Two matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS)-based methods were compared for their ability to identify viridans streptococci. One approach employed a reference database and software developed in-house. All inhouse measurements were performed using an Autoflex II Instrument (Bruker Daltonics GmbH, Germany). The other system, a VITEK-MS (BioMérieux, France) was operated on the commercially available V2.0 Knowledge Base for Clinical Use database. Clinical isolates of viridans streptococci (n=184) were examined...
September 2017: Annals of Laboratory Medicine
https://www.readbyqxmd.com/read/28643452/emerging-nanotechnology-and-advanced-materials-for-cancer-radiation-therapy
#13
REVIEW
Guosheng Song, Liang Cheng, Yu Chao, Kai Yang, Zhuang Liu
Radiation therapy (RT) including external beam radiotherapy (EBRT) and internal radioisotope therapy (RIT) has been widely used for clinical cancer treatment. However, owing to the low radiation absorption of tumors, high doses of ionizing radiations are often needed during RT, leading to severe damages to normal tissues adjacent to tumors. Meanwhile, the RT efficacies are limited by different mechanisms, among which the tumor hypoxia-associated radiation resistance is a well-known one, as there exists hypoxia inside most solid tumors while oxygen is essential to enhance radiation-induced DNA damages...
June 23, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28643230/crosstalk-between-m2-macrophages-and-glioma-stem-cells
#14
Leora M Nusblat, Molly J Carroll, Charles M Roth
PURPOSE: Given its extremely poor prognosis, there is a pressing need for an improved understanding of the biology of glioblastoma multiforme (GBM), including the roles of tumor subpopulations that may contribute to their growth rate and therapy resistance. The most malignant phenotypes of GBM have been ascribed to the presence of subpopulations of cancer stem cells (CSCs), which are resistant to chemotherapeutic drugs and ionizing radiation and which promote invasiveness and metastasis...
June 22, 2017: Cellular Oncology (Dordrecht)
https://www.readbyqxmd.com/read/28642964/metastasis-of-breast-cancer-cells-to-the-bone-lung-and-lymph-nodes-promotes-resistance-to-ionizing-radiation
#15
Takamitsu Hara, Manabu Iwadate, Kazunoshin Tachibana, Satoshi Waguri, Seiichi Takenoshita, Nobuyuki Hamada
BACKGROUND: Metastasis represents the leading cause of breast cancer deaths, necessitating strategies for its treatment. Although radiotherapy is employed for both primary and metastatic breast cancers, the difference in their ionizing radiation response remains incompletely understood. This study is the first to compare the radioresponse of a breast cancer cell line with its metastatic variants and report that such metastatic variants are more radioresistant. MATERIALS AND METHODS: A luciferase expressing cell line was established from human basal-like breast adenocarcinoma MDA-MB-231 and underwent in vivo selections, whereby a cycle of inoculations into the left cardiac ventricle or the mammary fat pad of athymic nude mice, isolation of metastases to the bone, lung and lymph nodes visualized with bioluminescence imaging, and expansion of obtained cells was repeated twice or three times...
June 22, 2017: Strahlentherapie und Onkologie: Organ der Deutschen Röntgengesellschaft ... [et Al]
https://www.readbyqxmd.com/read/28642840/cytolethal-distending-toxin-enhances-radiosensitivity-in-prostate-cancer-cells-by-regulating-autophagy
#16
Hwai-Jeng Lin, Hsin-Ho Liu, Chia-Der Lin, Min-Chuan Kao, Yu-An Chen, Chuan Chiang-Ni, Zhi-Pei Jiang, Mei-Zi Huang, Chun-Jung Lin, U-Ging Lo, Li-Chiung Lin, Cheng-Kuo Lai, Ho Lin, Jer-Tsong Hsieh, Cheng-Hsun Chiu, Chih-Ho Lai
Cytolethal distending toxin (CDT) produced by Campylobacter jejuni contains three subunits: CdtA, CdtB, and CdtC. Among these three toxin subunits, CdtB is the toxic moiety of CDT with DNase I activity, resulting in DNA double-strand breaks (DSB) and, consequently, cell cycle arrest at the G2/M stage and apoptosis. Radiation therapy is an effective modality for the treatment of localized prostate cancer (PCa). However, patients often develop radioresistance. Owing to its particular biochemical properties, we previously employed CdtB as a therapeutic agent for sensitizing radioresistant PCa cells to ionizing radiation (IR)...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28642474/comparing-dna-enrichment-of-proliferating-cells-following-administration-of-different-stable-isotopes-of-heavy-water
#17
Don E Farthing, Nataliya P Buxbaum, Philip J Lucas, Natella Maglakelidze, Brittany Oliver, Jiun Wang, Kevin Hu, Ehydel Castro, Catherine V Bare, Ronald E Gress
Deuterated water ((2)H2O) is a label commonly used for safe quantitative measurement of deuterium enrichment into DNA of proliferating cells. More recently, it has been used for labeling proteins and other biomolecules. Our in vitro - in vivo research reports important stable isotopic labeling enrichment differences into the DNA nucleosides and their isotopologues (e.g. deoxyadenosine (dA) M + 1, dA M + 2, dA M + 3), as well as tumor cell proliferation effects for various forms of commercially available stable heavy water ((2)H2O, H2(18)O, and (2)H2(18)O)...
June 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28641544/post-mortem-redistribution-of-drugs-current-state-of-knowledge
#18
Caroline Sastre, Christophe Bartoli, Valerie Baillif-Couniou, Georges Leonetti, Anne-Laure Pelissier-Alicot
BACKGROUND: Drug concentrations obtained from post mortem samples do not necessarily reflect the concentrations at the time of death, and variations of concentration may be observed between different sites and/or different sampling times. These phenomena, collectively termed post mortem redistribution, concern numerous molecules (medications, drugs of abuse, gases, etc.) and can complicate the interpretation of toxicological analyses. METHODS: Literature review...
June 22, 2017: Current Pharmaceutical Design
https://www.readbyqxmd.com/read/28641523/radiosensitizing-effect-of-electrochemotherapy-a-systematic-review-of-protocols-and-efficiency
#19
Zohre Rezaee, Ali Yadollahpour, Samaneh Rashidi, Pramod S Kunwar
OBJECTIVE: Electrochemotherapy (ECT) is a combination of electroporation (EP) and chemotherapy and has been reported as a potential radiosensitizing agent for radiation therapy. The main objective of this study was to systematically review of the literature to evaluate the effectiveness of ECT in sensitization of tumors to ionization radiation. In addition, the clinical considerations and mechanisms of action of radiosensitizing effect are discussed. METHODS: The databases of Medline (PubMed), Embase, Scopus, Cochrane library, Web of Science, Biomed central, Science Direct, and Google scholar up to March 30th 2017 were explored...
June 21, 2017: Current Drug Targets
https://www.readbyqxmd.com/read/28641506/regulatory-forum-opinion-piece-imaging-applications-in-toxicologic-pathology-recommendations-for-use-in-regulated-nonclinical-toxicity-studies
#20
Robert R Maronpot, Abraham Nyska, Sean P Troth, Kathleen Gabrielson, Polina Sysa-Shah, Vyacheslav Kalchenko, Yuri Kuznetsov, Alon Harmelin, Yael S Schiffenbauer, David Bonnel, Jonathan Stauber, Yuval Ramot
Available imaging systems for use in preclinical toxicology studies increasingly show utility as important tools in the toxicologic pathologist's armamentarium, permit longitudinal evaluation of functional and morphological changes in tissues, and provide important information such as organ and lesion volume not obtained by conventional toxicology study parameters. Representative examples of practical imaging applications in toxicology research and preclinical studies are presented for ultrasound, positron emission tomography/single-photon emission computed tomography, optical, magnetic resonance imaging, and matrix-assisted laser desorption ionization-imaging mass spectrometry imaging...
June 2017: Toxicologic Pathology
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