keyword
MENU ▼
Read by QxMD icon Read
search

Secondary ion mass spectrometry

keyword
https://www.readbyqxmd.com/read/28642031/clustering-of-ms-2-spectra-using-unsupervised-methods-to-aid-the-identification-of-secondary-metabolites-from-pseudomonas-aeruginosa
#1
Tobias Depke, Raimo Franke, Mark Brönstrup
Pseudomonas aeruginosa is an important opportunistic pathogen that produces a large arsenal of small molecule virulence factors and quorum sensing signal molecules. The annotation of these secondary metabolites in untargeted, mass spectrometry-based metabolomics is difficult, as many of them cannot be found in common metabolite databases, and as manual annotation is tedious. We therefore developed an algorithm named CluMSID that uses cosine similarities of product ion spectra and neutral loss patterns in combination with unsupervised clustering methods such as multidimensional scaling, density based clustering and hierarchical clustering to group structurally similar compounds and hence facilitate their annotation...
June 4, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/28633407/exploring-fungus-plant-n-transfer-in-a-tripartite-ant-plant-fungus-mutualism
#2
Céline Leroy, Alain Jauneau, Yves Martinez, Armelle Cabin-Flaman, David Gibouin, Jérôme Orivel, Nathalie Séjalon-Delmas
Background and Aims: The plant Hirtella physophora , the ant Allomerus decemarticulatus and a fungus, Trimmatostroma sp., form a tripartite association. The ants manipulate both the plant trichomes and the fungus to build galleries under the stems of their host plant used to capture prey. In addition to its structural role, the fungus also improves nutrient uptake by the host plant. But it still remains unclear whether the fungus plays an indirect or a direct role in transferring nutrients to the plant...
June 13, 2017: Annals of Botany
https://www.readbyqxmd.com/read/28630783/highly-sensitive-colorimetric-assay-for-determining-fe-3-based-on-gold-nanoparticles-conjugated-with-glycol-chitosan
#3
Kyungmin Kim, Yun-Sik Nam, Yeonhee Lee, Kang-Bong Lee
A highly sensitive and simple colorimetric assay for the detection of Fe(3+) ions was developed using gold nanoparticles (AuNPs) conjugated with glycol chitosan (GC). The Fe(3+) ion coordinates with the oxygen atoms of GC in a hexadentate manner (O-Fe(3+)-O), decreasing the interparticle distance and inducing aggregation. Time-of-flight secondary ion mass spectrometry showed that the bound Fe(3+) was coordinated to the oxygen atoms of the ethylene glycol in GC, which resulted in a significant color change from light red to dark midnight blue due to aggregation...
2017: Journal of Analytical Methods in Chemistry
https://www.readbyqxmd.com/read/28626281/measurement-of-uranium-236-in-particles-by-secondary-ion-mass-spectrometry
#4
David S Simons, John D Fassett
The determination of the relative isotopic abundance by secondary ion mass spectrometry of (236)U in uranium-containing material is complicated by the presence of (235)U(1)H(+) ions at the same nominal mass as the uranium isotopic peak. The net intensity of the (236)U signal is usually determined by a peak-stripping procedure, whereby the (235)U(1)H(+) contribution is obtained by applying the (238)U(1)H(+)/(238)U(+) ratio to the (235)U(+) signal. The subtraction of one signal from another has consequences for the uncertainty of the final (236)U abundance determination that may be especially significant when the amount of sample is limited, as is the case with small uranium particles that are of great interest for nuclear safeguards...
February 2017: Journal of Analytical Atomic Spectrometry
https://www.readbyqxmd.com/read/28623701/transition-temperature-of-poly-methyl-methacrylate-determined-by-time-of-flight-secondary-ion-mass-spectrometry-and-contact-angle-measurements
#5
Yi Fu, Yiu-Ting R Lau, Lu-Tao Weng, Kai-Mo Ng, Chi-Ming Chan
The surface chain conformations of poly(methyl methacrylate) (PMMA) at different temperatures were extensively studied by time-of-flight secondary ion mass spectrometry (ToF-SIMS). Similar to our previous experimental studies on polystyrene (PS) and poly(2, 3, 4, 5, 6-pentafluorostyrene) (5FPS), a transition temperature (TT) could be identified through the principal component analysis (PCA) of the ToF-SIMS spectra obtained from the PMMA samples annealed at different temperatures. Interestingly, our results show that the TT depended on molecular weight and was about 50-60˚C below the bulk glass transition temperature (Tg) and therefore could possibly be related to the surface glass transition temperature (Tg(S))...
June 1, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28617583/tof-sims-depth-profiling-of-ps-b-pmma-block-copolymers-using-arn-c60-and-cs-sputtering-ions
#6
T Terlier, G Zappalà, C Marie, D Leonard, J-P Barnes, A Licciardello
Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a high performance tool for molecular depth profiling of polymer films, in particular when they are structured in microphases. However, a major issue is the degradation of polymer materials under ion irradiation in reactions such as cross-linking, chain breaking, or reorganization processes of polymers which have been demonstrated for materials such as polystyrene (PS) and poly(methyl methacrylate) (PMMA). This work aims at comparing ToF-SIMS molecular depth profiling of structured polymers (polystyrene (PS)-b-polymethyl methacrylate (PMMA) block copolymers (BCP)) using either ultralow energy cesium or the more recently introduced C60(++) (under NO dosing and with sample cooling) and argon cluster ion beams (using Ar1500(+) ions at 5 keV)...
June 15, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28614950/grafting-of-architecture-controlled-poly-styrene-sodium-sulfonate-onto-titanium-surfaces-using-bio-adhesive-molecules-surface-characterization-and-biological-properties
#7
Hamza Chouirfa, Margaret D M Evans, David G Castner, Penny Bean, Dimitri Mercier, Anouk Galtayries, Céline Falentin-Daudré, Véronique Migonney
This contribution reports on grafting of bioactive polymers such as poly(sodium styrene sulfonate) (polyNaSS) onto titanium (Ti) surfaces. This grafting process uses a modified dopamine as an anchor molecule to link polyNaSS to the Ti surface. The grafting process combines reversible addition-fragmentation chain transfer polymerization, postpolymerization modification, and thiol-ene chemistry. The first step in the process is to synthetize architecture controlled polyNaSS with a thiol end group. The second step is the adhesion of the dopamine acrylamide (DA) anchor onto the Ti surfaces...
June 14, 2017: Biointerphases
https://www.readbyqxmd.com/read/28612342/effect-of-glycine-nitrogen-on-lettuce-growth-under-soilless-culture-a-metabolomics-approach-to-identify-the-main-changes-occurred-in-plant-primary-and-secondary-metabolism
#8
Xiao Yang, Lei Feng, Li Zhao, Xiaosong Liu, Danial Hassani, Danfeng Huang
BACKGROUND: Lettuce is a significant source of antioxidants and bioactive compounds. Nitrate is a cardinal fertilizer in horticulture and influences vegetable yield and quality; however, the negative effects of nitrate on the biosynthesis of flavonoids require further study. It is expected that using fertilizers containing organic N could promote the synthesis of health-promoting compounds. RESULTS: Lettuces were hydroponically cultured in media containing 9 mM nitrate or 9 mM glycine for 4 weeks...
June 14, 2017: Journal of the Science of Food and Agriculture
https://www.readbyqxmd.com/read/28608905/detection-of-sio2-nanoparticles-in-lung-tissue-by-tof-sims-imaging-and-fluorescence-microscopy
#9
Lothar Veith, Antje Vennemann, Daniel Breitenstein, Carsten Engelhard, Martin Wiemann, Birgit Hagenhoff
The direct detection of nanoparticles in tissues at high spatial resolution is a current goal in nanotoxicology. Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is widely used for the direct detection of inorganic and organic substances with high spatial resolution but its capability to detect nanoparticles in tissue sections is still insufficiently explored. To estimate the applicability of this technique for nanotoxicological questions, comparative studies with established techniques on the detection of nanoparticles can offer additional insights...
June 13, 2017: Analyst
https://www.readbyqxmd.com/read/28608848/furanoterpene-diversity-and-variability-in-the-marine-sponge-spongia-officinalis-from-untargeted-lc-ms-ms-metabolomic-profiling-to-furanolactam-derivatives
#10
Cléa Bauvais, Natacha Bonneau, Alain Blond, Thierry Pérez, Marie-Lise Bourguet-Kondracki, Séverine Zirah
The Mediterranean marine sponge Spongia officinalis has been reported as a rich source of secondary metabolites and also as a bioindicator of water quality given its capacity to concentrate trace metals. In this study, we evaluated the chemical diversity within 30 S. officinalis samples collected over three years at two sites differentially impacted by anthropogenic pollutants located near Marseille (South of France). Untargeted liquid chromatography-mass spectrometry (LC-MS) metabolomic profiling (C18 LC, ESI-Q-TOF MS) combined with XCMS Online data processing and multivariate statistical analysis revealed 297 peaks assigned to at least 86 compounds...
June 13, 2017: Metabolites
https://www.readbyqxmd.com/read/28606410/effects-of-silane-and-mdp-based-primers-application-orders-on-zirconia-resin-adhesion-a-tof-sims-study
#11
Shu-Fen Chuang, Li-Li Kang, Yi-Chuan Liu, Jui-Che Lin, Ching-Cheng Wang, Hui-Min Chen, Cheng-Kun Tai
OBJECTIVE: To evaluate the 3-methacryloyloxypropyltrimethoxysilane (MPS)- and 10-methacryloyloxydecyl-dihydrogen-phosphate (MDP)-base primers, in their single or sequential applications, with regard to modifying zirconia surfaces and improving resin-zirconia adhesion. METHODS: Zirconia disks received different treatments: without primer (Zr), MPS-base primer (S), MDP-base primer (M), MPS/MDP mixture (SMmix), MPS followed by MDP (SM), and MDP followed by MPS (MS)...
June 9, 2017: Dental Materials: Official Publication of the Academy of Dental Materials
https://www.readbyqxmd.com/read/28597894/deciphering-the-aqueous-chemistry-of-glyoxal-oxidation-with-hydrogen-peroxide-using-molecular-imaging
#12
Xiao Sui, Yufan Zhou, Fei Zhang, Jianmin Chen, Zihua Zhu, Xiao-Ying Yu
Aqueous surfaces after photochemical and dark reactions of glyoxal and hydrogen peroxide (H2O2) have been studied using a microfluidic reactor coupled with an in situ liquid time-of-flight secondary ion mass spectrometry (ToF-SIMS) for the first time. Spectral principal component analysis was used to determine similarities and differences among various photochemical aging and dark reaction samples and controls. Compared with previous results using bulk solutions, our unique liquid surface molecular imaging approach provided observations of glyoxal hydration (i...
June 9, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28591660/the-effect-of-advanced-secondary-municipal-wastewater-treatment-on-the-molecular-composition-of-dissolved-organic-matter
#13
Andrew C Maizel, Christina K Remucal
There is a growing interest in water reuse and in recovery of nutrients from wastewater. Because many advanced treatment processes are designed to remove organic matter, a better understanding of the composition of dissolved organic matter (DOM) in wastewater is needed. To that end, we assessed DOM in the Nine Springs Wastewater Treatment Plant in Madison, Wisconsin by UV-visible spectroscopy and Fourier transform-ion cyclotron resonance mass spectrometry. Samples were collected from the influent and effluent of two different secondary treatment processes and their respective secondary clarifiers, the UV disinfection unit, and an Ostara treatment system, which produces struvite via chemical precipitation...
May 26, 2017: Water Research
https://www.readbyqxmd.com/read/28589950/mycelium-mediated-transfer-of-water-and-nutrients-stimulates-bacterial-activity-in-dry-and-oligotrophic-environments
#14
Anja Worrich, Hryhoriy Stryhanyuk, Niculina Musat, Sara König, Thomas Banitz, Florian Centler, Karin Frank, Martin Thullner, Hauke Harms, Hans-Hermann Richnow, Anja Miltner, Matthias Kästner, Lukas Y Wick
Fungal-bacterial interactions are highly diverse and contribute to many ecosystem processes. Their emergence under common environmental stress scenarios however, remains elusive. Here we use a synthetic microbial ecosystem based on the germination of Bacillus subtilis spores to examine whether fungal and fungal-like (oomycete) mycelia reduce bacterial water and nutrient stress in an otherwise dry and nutrient-poor microhabitat. We find that the presence of mycelia enables the germination and subsequent growth of bacterial spores near the hyphae...
June 7, 2017: Nature Communications
https://www.readbyqxmd.com/read/28587700/the-composition-of-poly-ethylene-terephthalate-pet-surface-precipitates-determined-at-high-resolving-power-by-tandem-mass-spectrometry-imaging
#15
Gregory L Fisher, John S Hammond, Scott R Bryan, Paul E Larson, Ron M A Heeren
We present the first demonstration of a general method for the chemical characterization of small surface features at high magnification via simultaneous collection of mass spectrometry (MS) imaging and tandem MS imaging data. High lateral resolution tandem secondary ion MS imaging is employed to determine the composition of surface features on poly(ethylene terephthalate) (PET) that precipitate during heat treatment. The surface features, probed at a lateral resolving power of<200 nm using a surface-sensitive ion beam, are found to be comprised of ethylene terephthalate trimer at a greater abundance than is observed in the surrounding polymer matrix...
June 7, 2017: Microscopy and Microanalysis
https://www.readbyqxmd.com/read/28586192/selenium-functionalized-graphene-oxide-that-can-modulate-the-balance-of-reactive-oxygen-species
#16
Jiahao Xia, Feng Li, Shaobo Ji, Huaping Xu
Graphene oxide (GO) is an important two-dimensional material since it is water soluble and can be functionalized to adapt to different applications. However, the current covalent functionalization methods usually require hash conditions, long duration and sometimes even multi-steps, while noncovalent functionalization is inevitably unstable, especially under physiological environment where competing species exist. Diselenide bond is a dynamic covalent bond and can respond to both redox condition and visible light irradiation in a sensitive manner...
June 6, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28584389/low-temperature-plasma-for-the-preparation-of-crater-walls-for-compositional-depth-profiling-of-thin-inorganic-multilayers
#17
Shin Muramoto, Joe Bennett
An indirect, compositional depth profiling of an inorganic multilayer system using a helium low temperature plasma (LTP) containing 0.2% (v/v) SF6 was evaluated. A model multilayer system consisting of four 10 nm layers of silicon separated by four 50 nm layers of tungsten was plasma-etched for (10, 20, and 30) s at substrate temperatures of (50, 75, and 100) °C to obtain crater walls with exposed silicon layers that were then visualized using time-of-flight secondary ion mass spectrometry (ToF-SIMS) to determine plasma-etching conditions that produced optimum depth resolutions...
June 2017: Surface and Interface Analysis: SIA
https://www.readbyqxmd.com/read/28581710/biotransformation-of-silver-released-from-nanoparticle-coated-titanium-implants-revealed-in-regenerating-bone
#18
Hua Geng, Gowsihan Poologasundarampillai, Naomi Todd, Aine Devlin-Mullin, Katie L Moore, Zahra Golrokhi, James B Gilchrist, Eric Jones, Richard J Potter, Chris Sutcliffe, Marie O'Brien, David W L Hukins, Sarah Cartmell, Christopher A Mitchell, Peter D Lee
Antimicrobial silver nanoparticle coatings have attracted interest for reducing prosthetic joint infection. However, few studies report in vivo investigations of the biotransformation of silver nanoparticles within the regenerating tissue and its impact on bone formation. We present a longitudinal investigation of the osseointegration of silver nanoparticle-coated additive manufactured titanium implants in rat tibial defects. Correlative imaging at different time points using nanoscale secondary ion mass spectrometry, transmission electron microscopy (TEM), histomorphometry, and 3D X-ray microcomputed tomography provided quantitative insight from the nano- to macroscales...
June 16, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28575833/source-apportionment-and-health-risk-assessment-among-specific-age-groups-during-haze-and-non-haze-episodes-in-kuala-lumpur-malaysia
#19
Nor Azura Sulong, Mohd Talib Latif, Md Firoz Khan, Norhaniza Amil, Matthew J Ashfold, Muhammad Ikram Abdul Wahab, Kok Meng Chan, Mazrura Sahani
This study aims to determine PM2.5 concentrations and their composition during haze and non-haze episodes in Kuala Lumpur. In order to investigate the origin of the measured air masses, the Numerical Atmospheric-dispersion Modelling Environment (NAME) and Global Fire Assimilation System (GFAS) were applied. Source apportionment of PM2.5 was determined using Positive Matrix Factorization (PMF). The carcinogenic and non-carcinogenic health risks were estimated using the United State Environmental Protection Agency (USEPA) method...
May 30, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28574563/reactive-oxygen-species-formed-in-aqueous-mixtures-of-secondary-organic-aerosols-and-mineral-dust-influencing-cloud-chemistry-and-public-health-in-the-anthropocene
#20
Haijie Tong, Pascale S J Lakey, Andrea M Arangio, Joanna Socorro, Christopher J Kampf, Thomas Berkemeier, William H Brune, Ulrich Pöschl, Manabu Shiraiwa
Mineral dust and secondary organic aerosols (SOA) account for a major fraction of atmospheric particulate matter, affecting climate, air quality and public health. How mineral dust interacts with SOA to influence cloud chemistry and public health, however, is not well understood. Here, we investigated the formation of reactive oxygen species (ROS), which are key species of atmospheric and physiological chemistry, in aqueous mixtures of SOA and mineral dust by applying electron paramagnetic resonance (EPR) spectrometry in combination with a spin-trapping technique, liquid chromatography-tandem mass spectrometry (LC-MS/MS), and a kinetic model...
June 2, 2017: Faraday Discussions
keyword
keyword
45836
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"