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https://www.readbyqxmd.com/read/28432655/direct-analysis-of-organic-compounds-in-liquid-using-a-miniature-photoionization-ion-trap-mass-spectrometer-with-pulsed-carrier-gas-capillary-inlet
#1
Xinqiong Lu, Quan Yu, Qian Zhang, Kai Ni, Xiang Qian, Fei Tang, Xiaohao Wang
A miniature ion trap mass spectrometer with capillary direct sampling and vacuum ultraviolet photoionization source was developed to conduct trace analysis of organic compounds in liquids. Self-aspiration sampling is available where the samples are drawn into the vacuum chamber through a capillary with an extremely low flow rate (less than 1 μL/min), which minimizes sample consumption in each analysis to tens of micrograms. A pulsed gas-assisted inlet was designed and optimized to promote sample transmission in the tube and facilitate the cooling of ions, thereby improving instrument sensitivity...
April 21, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28431455/uhplc-q-tof-ms-ms-based-screening-and-characterization-of-metabolites-of-cnidilin-in-human-liver-microsomes
#2
Lin Yuan, Yuqian Zhang, Man Liao, Yanyan Liu, Changchen Wan, Lantong Zhang
Cnidilin is an active natural furocoumarin ingredient originating from well-known traditional Chinese medicine Radix Angelicae dahuricae. In the present study, an efficient approach was developed for the screening and identification of cnidilin metabolites using ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry. In this approach, an on-line data acquisition method multiple mass defect filter (MMDF) combined with dynamic background subtraction was developed to trace all probable metabolites...
April 21, 2017: Biomedical Chromatography: BMC
https://www.readbyqxmd.com/read/28429451/a-strong-cis-effect-in-an-imidazole-imidazolium-substituted-alkene
#3
Dayne C Georgiou, Mohammad A Haghighatbin, Conor F Hogan, Michael S Scholz, James N Bull, Evan J Bieske, David J D Wilson, Jason L Dutton
We report the first example of an alkene with two carbon-bound substituents (imidazole and imidazolium rings) where the Z-isomer has a greater thermodynamic stability than the E-isomer which persists in both the gas phase and in solution. Theoretical calculations, solution fluorescence spectroscopy and gas-phase ion mobility mass spectrometry studies confirm the preference for the Z-isomer, the stability of which is traced to a non-covalent interaction between the imidazole lone pair and the imidazolium ring...
April 21, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28423470/quantification-of-near-attomole-gibberellins-in-floral-organs-dissected-from-single-arabidopsis-thaliana-flower
#4
Dongmei Li, Zhenpeng Guo, Cuimei Liu, Jincheng Li, Wenzhong Xu, Yi Chen
There remains a methodological bottleneck in the quantification of ultra-trace plant hormones in very tiny plant organs at a fresh weights below milligram. The challenge becomes even more serious in the determination of endogenous gibberellins (GAs), which are a class of compounds that are difficult to separate and detect. Herein, a quantitation method by ultra-high-performance liquid chromatography-tandem mass spectrometry was developed, combined with a derivatization technique in which GAs react with N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide in ethanol...
April 19, 2017: Plant Journal: for Cell and Molecular Biology
https://www.readbyqxmd.com/read/28423005/an-archosauromorph-dominated-ichnoassemblage-in-fluvial-settings-from-the-late-early-triassic-of-the-catalan-pyrenees-ne-iberian-peninsula
#5
Eudald Mujal, Josep Fortuny, Arnau Bolet, Oriol Oms, José Ángel López
The vertebrate recovery after the end-Permian mass extinction can be approached through the ichnological record, which is much more abundant than body fossils. The late Olenekian (Early Triassic) tetrapod ichnoassemblage of the Catalan Pyrenean Basin is the most complete and diverse of this age from Western Tethys. This extensional basin, composed of several depocenters, was formed in the latest phases of the Variscan orogeny (Pangea breakup) and was infilled by braided and meandering fluvial systems of the red-beds Buntsandstein facies...
2017: PloS One
https://www.readbyqxmd.com/read/28422204/interface-modulation-of-bacteriogenic-ag-agcl-nanoparticles-by-boosting-the-catalytic-activity-for-reduction-reactions-using-co-2-ions
#6
Hao Zhou, Lin Che, Xuyun Guo, Xue Wang, Jingjing Zhan, Minghuo Wu, Yufeng Hu, Xianliang Yi, Xuwang Zhang, Lifen Liu
Boosting the low catalytic activity of bacteriogenic Ag/AgCl nanoparticles (NPs) by adding Co(2+) in a model reaction, i.e. p-nitrophenol (PNP) reduction, was observed. Under optimal conditions, Co-Ag/AgCl NPs show an apparent rate constant (kapp) of 0.0837 s(-1) upon PNP reduction. Considering the trace amount of Co-Ag/AgCl NPs used in catalysis (about 1.2 μg), the activity parameter κ (which is the ratio of kapp and catalyst mass) can reach more than 6.97 × 10(4) s(-1) g(-1), which is 214-fold higher than that of pristine Ag/AgCl NPs...
April 19, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28420590/volume-and-dimensions-of-angiographically-normal-coronary-arteries-assessed-by-multidetector-computed-tomography
#7
Samuel Kiil Sørensen, Jørgen Tobias Kühl, Andreas Fuchs, Jakob Boesgaard Norsk, Lars Valeur Køber, Børge Grønne Nordestgaard, Klaus Fuglsang Kofoed
BACKGROUND: The objective of this study was to determine normal values for coronary artery volume (CAV) and individual vasculature and segment dimensions. METHODS: We examined 200 healthy volunteers with an Agatston score of 0 and a normal, high quality coronary CTA. Using 320 slice multidetector row CT and designated vessel tracing software with border detection algorithm, the main coronary arteries and branches were delineated and total and segmental dimensions calculated...
April 4, 2017: Journal of Cardiovascular Computed Tomography
https://www.readbyqxmd.com/read/28417198/biases-in-the-production-and-reception-of-collective-knowledge-the-case-of-hindsight-bias-in-wikipedia
#8
Aileen Oeberst, Ina von der Beck, Mitja D Back, Ulrike Cress, Steffen Nestler
The Web 2.0 enabled collaboration at an unprecedented level. In one of the flagships of mass collaboration-Wikipedia-a large number of authors socially negotiate the world's largest compendium of knowledge. Several guidelines in Wikipedia restrict contributions to verifiable information from reliable sources to ensure recognized knowledge. Much psychological research demonstrates, however, that individual information processing is biased. This poses the question whether individual biases translate to Wikipedia articles or whether they are prevented by its guidelines...
April 17, 2017: Psychological Research
https://www.readbyqxmd.com/read/28416223/study-on-emission-of-hazardous-trace-elements-in-a-350%C3%A2-mw-coal-fired-power-plant-part-2-arsenic-chromium-barium-manganese-lead
#9
Shilin Zhao, Yufeng Duan, Lei Chen, Yaning Li, Ting Yao, Shuai Liu, Meng Liu, Jianhong Lu
Hazardous Trace elements (HTEs) emitted from coal combustion has raised widespread concern. Studies on the emission characteristics of five HTEs, namely arsenic (As), chromium (Cr), barium (Ba), manganese (Mn), lead (Pb) at three different loads (100%, 83%, 71% output) and different coal types were performed on a 350 MW coal-fired power plant equipped with SCR, ESP + FF, and WFGD. HTEs in the flue gas at the inlet/outlet of each air pollution control device (APCD) were sampled simultaneously based on US EPA Method 29...
April 14, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28415902/metabolism-studies-on-hydroxygenkwanin-and-genkwanin-in-human-liver-microsomes-by-uhplc-q-tof-ms
#10
Lin Yuan, Caijuan Liang, Xinpeng Diao, Xiaoye Cheng, Man Liao, Lantong Zhang
Hydroxygenkwanin (HYGN) and genkwanin (GN) are major constituents of Genkwa Flos for the treatment of edema, ascites, cough, asthma, and cancer. This is a report about the investigation of the metabolic fate of HYGN and GN in human liver microsomes and the recombinant UGT enzymes by using ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS). An on-line data acquisition method multiple mass defect filter (MMDF) combined with dynamic background subtraction (DBS) was developed to trace all probable metabolites...
April 18, 2017: Xenobiotica; the Fate of Foreign Compounds in Biological Systems
https://www.readbyqxmd.com/read/28411816/a-novel-metal-organic-framework-composite-mil-101-cr-go-as-an-efficient-sorbent-in-dispersive-micro-solid-phase-extraction-coupling-with-uhplc-ms-ms-for-the-determination-of-sulfonamides-in-milk-samples
#11
Xiuna Jia, Pan Zhao, Xiu Ye, Lianjun Zhang, Ting Wang, Qinyu Chen, Xiaohong Hou
As a novel material, metal-organic framework/graphite oxide (MIL-101(Cr)@GO) has great potential for the pretreatment of trace analytes. In the present study, MIL-101(Cr)@GO was synthesized using a solvothermal synthesis method at the nanoscale and was applied as sorbent in the dispersive micro-solid phase extraction (DMSPE) for the enrichment of the trace sulfonamides (SAs) from milk samples for the first time. Several experimental parameters including kinds of sorbents, the effect of pH, the amount of MIL-101(Cr)@GO, ionic strength, adsorption time, desorption solvent and desorption time were investigated...
July 1, 2017: Talanta
https://www.readbyqxmd.com/read/28411570/impacts-of-coal-fly-ash-on-plant-growth-and-accumulation-of-essential-nutrients-and-trace-elements-by-alfalfa-medicago-sativa-grown-in-a-loessial-soil
#12
Honghua He, Zhigang Dong, Qi Peng, Xia Wang, Chenbin Fan, Xingchang Zhang
Coal fly ash (CFA) is a problematic solid waste all over the world. One distinct beneficial reuse of CFA is its utilization in land application as a soil amendment. A pot experiment was carried out to assess the feasibility of using CFA to improve plant growth and increase the supply of plant-essential elements and selenium (Se) of a loessial soil for agricultural purpose. Plants of alfalfa (Medicago sativa) were grown in a loessial soil amended with different rates (5%, 10%, 20% and 40%) of CFA for two years and subjected to four successive cuttings...
April 12, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28411566/ambient-fine-particulate-matter-pm2-5-in-canadian-oil-sands-communities-levels-sources-and-potential-human-health-risk
#13
Md Aynul Bari, Warren B Kindzierski
An investigation of levels and potential sources affecting ambient fine particulate matter (PM2.5) and associated risk to public health was undertaken at two Canadian oil sands communities (Fort McKay and Fort McMurray) using a 4-year dataset (2010-2013). Geometric mean concentrations of PM2.5 at Fort McKay and Fort McMurray are not considered high and were 5.47μg/m(3) (interquartile range, IQR=3.02-8.55μg/m(3)) and 4.96μg/m(3) (IQR=3.20-7.04μg/m(3)), respectively. Carcinogenic risks of trace elements were below acceptable (1×10(-6)) and/or within tolerable risk (1×10(-4)), and non-carcinogenic risks were below a safe level of concern (hazard index=1)...
April 12, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28411464/development-validation-and-different-approaches-for-the-measurement-uncertainty-of-a-multi-class-veterinary-drugs-residues-lc-ms-method-for-feeds
#14
Andressa Camargo Valese, Luciano Molognoni, Naielly Coelho de Souza, Leandro Antunes de Sá Ploêncio, Ana Carolina Oliveira Costa, Fabiano Barreto, Heitor Daguer
A sensitive method for the simultaneous residues analysis of 62 veterinary drugs in feeds by liquid chromatography-tandem mass spectrometry has been developed and validated in accordance to Commission Decision 657/2002/EC. Additionally, limits of detection (LOD), limits of quantitation (LOQ), matrix effects and measurement uncertainty were also assessed. Extraction was performed for all analytes and respective internal standards in a single step and chromatographic separation was achieved in only 12min. LOQ were set to 0...
March 25, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/28409445/ion-mobility-spectrometry-high-resolution-ltq-orbitrap-mass-spectrometry-for-analysis-of-homemade-explosives
#15
Nathan Hagan, Ilana Goldberg, Adam Graichen, Amanda St Jean, Ching Wu, David Lawrence, Plamen Demirev
The detailed chemical characterization of homemade explosives (HMEs) and other chemicals that can mimic or mask the presence of explosives is important for understanding and improving the performance of commercial instrumentation used for explosive detection. To that end, an atmospheric-pressure drift tube ion mobility spectrometry (IMS) instrument has been successfully coupled to a commercial tandem mass spectrometry (MS) system. The tandem MS system is comprised of a linear ion trap and a high resolution Orbitrap analyzer...
April 13, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28407972/determination-of-aflatoxin-m1-in-milk-samples-by-means-of-an-inductively-coupled-plasma-mass-spectrometry-based-immunoassay
#16
Emma Pérez, Pascual Martínez-Peinado, Francisco Marco, Luis Gras, José Miguel Sempere, Juan Mora, Guillermo Grindlay
An inductively coupled plasma mass spectrometry (ICP-MS)-based immunoassay has been developed to quantify aflatoxin M1 (AFM1) at ultra-trace levels in milk samples. AFM1 detection is carried out by means of a competitive immunoassay using secondary biotinylated antibodies and streptavidin-conjugated Au nanoparticles. After acid addition, nanoparticles are decomposed and Au signal is registered by means of ICP-MS. Results demonstrate that, under optimum conditions, the limit of detection of the immunoassay (0...
September 1, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28406389/the-informational-turn-in-food-politics-the-us-fda-s-nutrition-label-as-information-infrastructure
#17
Xaq Frohlich
This article traces the history of the US FDA regulation of nutrition labeling, identifying an 'informational turn' in the evolving politics of food, diet and health in America. Before nutrition labeling was introduced, regulators actively sought to segregate food markets from drug markets by largely prohibiting health information on food labels, believing such information would 'confuse' the ordinary food consumer. Nutrition labeling's emergence, first in the 1970s as consumer empowerment and then later in the 1990s as a solution to information overload, reflected the belief that it was better to manage markets indirectly through consumer information than directly through command-and-control regulatory architecture...
April 2017: Social Studies of Science
https://www.readbyqxmd.com/read/28405368/concurrence-in-the-ability-for-lipid-synthesis-between-life-stages-in-insects
#18
Bertanne Visser, Denis S Willett, Jeffrey A Harvey, Hans T Alborn
The ability to synthesize lipids is critical for an organism's fitness; hence, metabolic pathways, underlying lipid synthesis, tend to be highly conserved. Surprisingly, the majority of parasitoids deviate from this general metabolic model by lacking the ability to convert sugars and other carbohydrates into lipids. These insects spend the first part of their life feeding and developing in or on an arthropod host, during which they can carry over a substantial amount of lipid reserves. While many parasitoid species have been tested for lipogenic ability at the adult life stage, it has remained unclear whether parasitoid larvae can synthesize lipids...
March 2017: Royal Society Open Science
https://www.readbyqxmd.com/read/28402653/host-cell-protein-profiling-by-targeted-and-untargeted-analysis-of-data-independent-acquisition-mass-spectrometry-data-with-parallel-reaction-monitoring-verification
#19
Simion Kreimer, Yuanwei Gao, Somak Ray, Mi Jin, Zhijun Tan, Nesredin A Mussa, Li Tao, Zhengjian Li, Alexander R Ivanov, Barry L Karger
Host cell proteins (HCPs) are process-related impurities of biopharmaceuticals that remain at trace levels despite multiple stages of downstream purification. Currently, there is interest in implementing LC-MS in biopharmaceutical HCP profiling alongside conventional ELISA, because individual species can be identified and quantitated. Conventional data-dependent LC-MS is hampered by the low concentration of HCP-derived peptides, which are 5-6 orders of magnitude less abundant than the biopharmaceutical-derived peptides...
April 12, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28401661/chemical-discrimination-of-lubricant-marketing-types-using-dart-tofms
#20
Mark Maric, Lauren Harvey, Maren Tomcsak, Angelique Solano, Candice Bridge
RATIONALE: In comparison to other violent crimes, sexual assaults suffer from very low prosecution and conviction rates especially in the absence of DNA evidence. As a result, the forensic community needs to utilize other forms of trace contact evidence, like lubricant evidence, in order to provide a link between the victim and the assailant. METHODS: In this study, 90 personal bottled and condom lubricants from the three main marketing types, silicone-based, water-based and condoms, were characterized by direct analysis in real time-time of flight mass spectrometry (DART-TOFMS)...
April 12, 2017: Rapid Communications in Mass Spectrometry: RCM
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