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"Mass spectrometry"

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https://www.readbyqxmd.com/read/28732399/analysis-of-emerging-organic-contaminants-in-water-fish-and-suspended-particulate-matter-spm-in-the-joint-danube-survey-using-solid-phase-extraction-followed-by-uhplc-ms-ms-and-gc-ms-analysis
#1
Robert Loos, Simona Tavazzi, Giulio Mariani, Gert Suurkuusk, Bruno Paracchini, Gunther Umlauf
In the third Joint Danube Survey (JDS3), emerging organic contaminants were analysed in the dissolved water phase of samples from the Danube River and its major tributaries. Analyses were performed using solid-phase extraction (SPE) followed by ultra-high-pressure liquid chromatography triple-quadrupole mass spectrometry (UHPLC-MS-MS) and gas chromatography-mass spectrometry (GC-MS). The polar organic compounds analysed by UHPLC-MS-MS were 1H-benzotriazole, methylbenzotriazoles, carbamazepine, 10,11-dihydro-10,11-dihydroxy-carbamazepine, diclofenac, sulfamethox-azole, 2,4-D (2,4-dichlorophenoxyacetic acid), MCPA (2-methyl-4-chlorophenoxyacetic acid), metolachlor, cybutryne (irgarol), terbutryn, DEET (N,N-diethyl-m-toluamide), and several perfluoroalkyl acids (C6-C9; C8=perfluorooctanoic acid (PFOA)) and perfluorooctansulfonic acid (PFOS)...
July 17, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28732306/photostability-testing-using-online-reactor-hplc-hyphenation-and-mass-spectrometric-compound-identification-illustrated-by-ketoprofen-as-model-compound
#2
Jaber Assaf, Diego Zulkiewicz Gomes, Bernhard Wuest, Maria Kristina Parr
Investigations on the photochemical stability of pharmaceutical substances are mandatory in drug development and licensing as photo-induced degradation of an active pharmaceutical ingredient (API) may not only lead to decreased API concentrations but also to toxic or reactive products. Thus, the US Food and Drug Administration (FDA) and the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) issued Guidance for Industry Q1B "Photostability Testing of New Drug Substances and Products" for testing of pure but also packed drugs...
July 8, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28732136/an-approach-to-estimate-the-activation-energies-of-fragmentation-occurring-in-quadrupole-collision-cell-of-the-mass-spectrometer
#3
Ákos Kuki, Lajos Nagy, Miklós Zsuga, Sándor Kéki
The classical semi-quantitative Rice-Ramsperger-Kassel (RRK) theory was used for the calculation of the internal energy dependent reaction rate coefficient of the collision-induced dissociation (CID) reaction in tandem mass spectrometry (MS/MS). The survival yield (SY) was determined by the reaction rate equation for the unimolecular dissociation of the precursor ion. The parameters of the rate equation and the RRK model were approximated based on the instrumental conditions. We used the RRK equation for the description of the basic behavior of the fragmentation reactions and for the estimation of the internal energy of the precursor ion...
July 21, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28732132/entrapment-of-amino-acids-in-gas-phase-surfactant-assemblies-the-case-of-tryptophan-confined-in-positively-charged-1r-2s-dodecyl-2-hydroxy-1-methyl-2-phenylethyl-dimethylammonium-bromide-aggregates
#4
David Bongiorno, Valentina Calabrese, Leopoldo Ceraulo, Serena Indelicato, Vincenzo Turco Liveri
The ability of positively charged aggregates of the surfactant (1R,2S)-Dodecyl(2-hydroxy-1-methyl-2-phenylethyl)dimethylammonium bromide (DMEB) to incorporate D- or L-tryptophan in the gas-phase has been investigated by electrospray ion mobility mass spectrometry (ESI-IM-MS). Strongly impacted by the pH of the electrosprayed solutions, both protonated (T(+) ) and deprotonated (T(-) ) tryptophan are effectively included into the aggregates whereas, tryptophan in zwitterionic (T(0) ) form is practically absent in singly charged DMEB aggregates but can be found in multiply charged ones...
July 21, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28732111/characterization-of-metabolic-pathways-and-absorption-of-sea-cucumber-saponins-holothurin-a-and-echinoside-a-in-vitro-and-in-vivo
#5
Shanshan Song, Lingyu Zhang, Jian Cao, Gao Xiang, Peixu Cong, Ping Dong, Zhaojie Li, Changhu Xue, Yong Xue, Yuming Wang
Sea cucumber saponins (SCSs) exhibit a wide spectrum of bioactivities, but their metabolic characteristics are not well elucidated. In this study, the metabolism of holothurin A (HA) and echinoside A (EA), 2 major saponins in sea cucumber, by gut microflora were investigated. First, we conducted an in vitro study, where in the SCSs were incubated with intestinal microflora and the metabolites were detected by high pressure liquid chromatography-high resolution mass spectrometry. We also conducted an in vivo study on rats, where in the intestinal contents, serum, urine, and feces were collected and evaluated after oral administration of SCSs...
July 21, 2017: Journal of Food Science
https://www.readbyqxmd.com/read/28731711/identification-of-proteomic-features-to-distinguish-benign-pulmonary-nodules-from-lung-adenocarcinoma
#6
Simona G Codreanu, Megan D Hoeksema, Robbert J C Slebos, Lisa J Zimmerman, S M Jamshedur Rahman, Ming Li, Sheau-Chiann Chen, Heidi Chen, Rosana Eisenberg, Daniel C Liebler, Pierre P Massion
We hypothesized that distinct protein expression features of benign and malignant pulmonary nodules may reveal novel candidate biomarkers for the early detection of lung cancer. We performed proteome profiling by liquid chromatography-tandem mass spectrometry to characterize 34 resected benign lung nodules, 24 early stage untreated lung adenocarcinomas (ADCs) and biopsies of bronchial epithelium. Group comparisons identified 65 proteins that differentiate nodules from ADCs and normal bronchial epithelium, and 66 proteins that differentiate ADCs from nodules and normal bronchial epithelium...
July 21, 2017: Journal of Proteome Research
https://www.readbyqxmd.com/read/28731694/the-foliar-desiccators-glyphosate-carfentrazone-and-paraquat-affect-the-technological-and-chemical-properties-of-cowpea-grains
#7
Igor da Silva Lindemann, Gustavo Heinrich Lang, Jessica Fernanda Hoffmann, Cesar Valmor Rombaldi, Mauricio de Oliveira, Moacir Cardoso Elias, Nathan Levien Vanier
The effects of the use of glyphosate (GLY), glyphosate plus carfentrazone (GLY/CAR), and paraquat (PAR) as plant desiccators on the technological and chemical properties of cowpea grains were investigated. All studied desiccants provided lower cooking time to freshly harvested cowpea. However, the coat color of PAR- and GLY/CAR-treated cowpea was reddish than control treatment. Principal component analysis (PCA) from liquid chromatography-mass spectrometry (LC-MS) data sets showed a clear distinction among cowpea from the different treatments...
July 21, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28731689/dinuclear-coordination-compounds-based-on-a-5-nitropicolinic-carboxylate-ligand-with-single-molecule-magnet-behavior
#8
Álvaro Raya-Barón, Itziar Oyarzabal, Francisco M Arrabal-Campos, José Manuel Seco, Antonio Rodríguez-Diéguez, Ignacio Fernández
Isostructural dinuclear dysprosium and yttrium coordination compounds based on the 5-nitropicolinic carboxylate ligand were synthesized and characterized. The formation of these air-stable complexes is achieved via solvothermal routes employing water as the reaction solvent. The dysprosium-based complex exhibits single-molecule magnet behavior with frequency dependence of the out-of-phase susceptibility at zero direct-current field. High-resolution mass spectrometry (electrospray ionization) experiments and advanced NMR methods including diffusion NMR techniques were applied on the diamagnetic yttrium analogue and established that these species retained their solid-state structure in solution with hydrodynamic radii of 6...
July 21, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28731687/intramolecular-c-h-and-c-f-bond-oxygenation-by-site-differentiated-tetranuclear-manganese-models-of-the-oec
#9
Kurtis M Carsch, Graham de Ruiter, Theodor Agapie
The dangler manganese center in the oxygen-evolving complex (OEC) of photosystem II plays an important role in the oxidation of water to dioxygen. Inspired by the structure of the OEC, we synthesized a series of site-differentiated tetra-manganese clusters [LMn3(PhPz)3OMn][OTf]x (2: x = 2; 3: x = 1) that features an apical manganese ion-distinct from the others-that is appended to a trinuclear manganese core through an μ4-oxygen atom bridge. This cluster design was targeted to facilitate studies of high-valent Mn-oxo formation, which is a proposed step in the mechanism for water oxidation by the OEC...
July 21, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28731680/nitrilotriacetic-amine-functionalized-polymeric-core-shell-nanoparticles-as-enzyme-immobilization-supports
#10
Dominic Keller, Ana Beloqui, Monica Martínez-Martínez, Manuel Ferrer, Guillaume Delaittre
Nitrilotriacetic amine (NTA) functionalized nanoparticles obtained by aqueous polymerization-induced self-assembly (PISA) are introduced as immobilization supports for polyhistidine-functionalized (His-tagged) enzymes. A novel initiator for nitroxide-mediated polymerization based on the nitroxide SG1 and carrying a protected NTA moiety was first synthesized. Size-exclusion chromatography (SEC) and electrospray ionization mass spectrometry (ESI-MS) proved the ability of this initiator to produce well-defined end-functional vinyl polymers...
July 21, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28731678/stable-and-efficient-cuo-based-photocathode-through-oxygen-rich-composition-and-au-pd-nanostructure-incorporation-for-solar-hydrogen-production
#11
Saeid Masudy-Panah, Roozbeh Siavash Moakhar, Chin Sheng Chua, Ajay Kumar Kushwaha, Goutam Kumar Dalapati
Enhancing stability against photo-corrosion and improving photocurrent response are the main challenges toward the development of cupric oxide (CuO) based photocathodes for solar-driven hydrogen production. In this paper, stable and efficient CuO-photocathodes have been developed using in-situ materials engineering and through gold-palladium (Au-Pd) nanoparticles deposition on the CuO surface. The CuO photocathode exhibits a photocurrent generation of ~3 mA/cm2 at 0V v/s RHE. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis and X-ray spectroscopy (XPS) confirm the formation of oxygen-rich (O-rich) CuO film which demonstrate highly stable photocathode with retained photocurrent of ~90% for 20 minutes...
July 21, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28731593/synthesis-characterization-and-efficient-catalytic-activities-of-a-nickel-ii-porphyrin-remarkable-solvent-and-substrate-effects-on-participation-of-multiple-active-oxidants
#12
Cheal Kim, Hye Ahn, Jeong Bae, Min Kim, Kwon Bok, Ha Jeong, Suk Lee
A new nickel(II) porphyrin complex, [NiII(porp)] (1) has been synthesized and characterized by 1H NMR, 13C NMR and mass spectrometry analysis. This NiII porphyrin complex 1 catalyzed quantitatively the epoxidation reaction of a wide range of olefins with meta-chloroperoxybenzoic acid (MCPBA) under mild conditions. Reactivity and Hammett studies, H218O-exchange experiments, and the use of PPAA (peroxyphenylacetic acid) as a mechanistic probe suggested that participation of multiple active oxidants NiII-OOC(O)R 2, NiIV-Oxo 3, and NiIII-Oxo 4 in olefin epoxidation reactions by nickel porphyrin complex is markedly affected by solvent polarity and concentration and type of substrate...
July 21, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28731579/residual-dynamic-and-risk-assessment-of-dimethomorph-in-swiss-chard-grown-in-two-different-sites
#13
Md Humayun Kabir, A M Abd El-Aty, Md Musfiqur Rahman, Hyung Suk Chung, Han Sol Lee, Mi-Ra Kim, Byung-Joon Chang, Jing Wang, Ho-Chul Shin, Jae-Han Shim
Residue analysis of dimethomorph in Swiss chard cultivated at two different locations under greenhouse conditions was conducted using high-performance liquid chromatography-ultraviolet detector (HPLC-UVD) and confirmed by tandem mass spectrometry (LC-MS/MS). The randomly collected samples (over 14 days) were extracted with acetonitrile and purified using a Florisil solid-phase extraction (SPE) cartridge. Linearity over a concentration range of 0.05-50.0 mg/L had an excellent coefficient of determination (R(2) ) = 0...
July 21, 2017: Biomedical Chromatography: BMC
https://www.readbyqxmd.com/read/28731451/novel-blood-based-biomarkers-of-cognition-stress-and-physical-or-cognitive-training-in-older-adults-at-risk-of-dementia-preliminary-evidence-for-a-role-of-bdnf-irisin-and-the-kynurenine-pathway
#14
Olivia C Küster, Daria Laptinskaya, Patrick Fissler, Cathrin Schnack, Martina Zügel, Verena Nold, Franka Thurm, Sina Pleiner, Alexander Karabatsiakis, Björn von Einem, Patrick Weydt, Andre Liesener, Andreas Borta, Alexander Woll, Bastian Hengerer, Iris-Tatjana Kolassa, Christine A F von Arnim
 Psychosocial stress and physical, cognitive, and social activity predict the risk of cognitive decline and dementia. The aim of this study was to elucidate brain-derived neurotrophic factor (BDNF), irisin, and the kynurenine pathway (KP) as potential underlying biological correlates. We evaluated associations of irisin and the KP with BDNF in serum and with cognition, stress, and activities. Furthermore, changes in serum concentrations of BDNF, irisin, and KP metabolites were investigated after physical or cognitive training...
July 18, 2017: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/28731365/chemical-composition-and-antimigraine-activity-of-essential-oil-of-angelicae-dahuricae-radix
#15
Jingbo Sun, He Li, Jinghui Sun, Huimin Liu, Jianguang Chen, Chunmei Wang
The aim of this study was to explore the chemical composition and the effect of essential oil of Angelicae dahuricae radix on a nitroglycerin (NTG)-induced rat model of migraine. The CO2 supercritical fluid extraction method was optimized for the extraction of essential oil of A. dahuricae radix (EOAD) and its chemical composition was determined. The migraine model was established by subcutaneous injection of NTG (10 mg/kg) 1 h after the last administration of EOAD. The therapeutic effect of EOAD and its underlying mechanism were assessed by monitoring behavioral changes, levels of nitric oxide (NO) in serum and brain tissues, plasma levels of calcitonin gene-related peptide (CGRP) and endothelin (ET), and ET/NO ratio...
July 21, 2017: Journal of Medicinal Food
https://www.readbyqxmd.com/read/28731323/analyzing-liposomal-drug-delivery-systems-in-three-dimensional-cell-culture-models-using-maldi-imaging-mass-spectrometry
#16
Jessica K Lukowski, Eric M Weaver, Amanda B Hummon
Cancer chemotherapeutics often fail to reach all diseased cells. To help solve this problem, researchers are investigating novel drug delivery systems. Liposomes are an attractive option due to their low toxicity, high biocompatibility, and potential to carry a large amount of a drug to the tumor site, all while avoiding being eliminated from the body. This study evaluates the penetration of doxorubicin-encased liposomes into three-dimensional cell cultures, or spheroids. Liposomes composed of lipids containing head groups of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and cholesterol were created by extrusion...
July 21, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28731299/human-biomonitoring-of-lead-exposure
#17
Katrin Klotz, Thomas Göen
After a chronic exposure, lead accumulates in the human body, especially in bones and teeth. Critical effects of lead affect the nervous system, reproduction, fertility as well as genotoxicity and carcinogenicity [1]. Analyses of lead concentrations in human biological material are performed using inductively coupled plasma mass spectrometry and atomic absorption spectrometry, but also electrochemical methods and X-ray fluorescence spectroscopy. The predominant sample matrices include blood and bone, as well as urine, hair, nail, and saliva...
April 10, 2017: Metal Ions in Life Sciences
https://www.readbyqxmd.com/read/28731206/comparative-plasma-and-interstitial-fluid-pharmacokinetics-of-flunixin-meglumine-and-ceftiofur-hydrochloride-following-individual-and-co-administration-in-dairy-cows
#18
P J Gorden, M D Kleinhenz, L W Wulf, S J Rajewski, C Wang, R Gehring, J F Coetzee
Ceftiofur (CEF) and flunixin meglumine (FLU) are two drugs approved for use in beef and dairy cattle that are frequently used in combination for many diseases. These two drugs are the most commonly used drugs in dairy cattle in their respective drug classes. Two research groups have recently published manuscripts demonstrating altered pharmacokinetics of FLU and CEF in cows affected with naturally occurring mastitis. The objective of this study was to determine whether pharmacokinetics of flunixin meglumine administered intravenously or intramuscularly administered ceftiofur hydrochloride would be altered when co-administered versus individual administration to healthy dairy cattle...
July 21, 2017: Journal of Veterinary Pharmacology and Therapeutics
https://www.readbyqxmd.com/read/28731105/a-comparative-vuv-absorption-mass-spectroscopy-study-on-protonated-peptides-of-different-size
#19
D Egorov, R Hoekstra, T Schlathölter
The ionization of gas-phase protonated peptides and proteins can induce molecular responses ranging from purely non-dissociative ionization to extensive multifragmentation of the system. In the case of soft X-ray photoionization, a monotonic transition between both regimes occurs in the mass range between 0.5 and 10 kDa. Despite the localized nature of the photoabsorption, excitation energy equilibrates before fragmentation sets in and the transition reflects the increase of the heat capacity with protein size...
July 21, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28730955/itraq-based-proteomic-analysis-of-appsw-ind-mice-provides-insights-into-the-early-changes-in-alzheimer-s-disease
#20
Nan Li, Pinghong Hu, Tiantian Xu, Huan Chen, Xiaoying Chen, Jianwen Hu, Xifei Yang, Lei Shi, Jian-Hong Luo, Junyu Xu
BACKGROUND: Several proteins have been identified as potential diagnostic biomarkers in imaging, genetic, or proteomic studies in Alzheimer disease (AD) patients and mouse models. However, biomarkers for presymptom diagnosis of AD are still under investigation, as are the presymptom molecular changes in AD pathogenesis. OBJECTIVE: In this study, we aim to analyzed the early proteomic changes in APPSw,Ind mice and to conduct further functional studies on interesting proteins...
July 19, 2017: Current Alzheimer Research
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