keyword
MENU ▼
Read by QxMD icon Read
search

Mass spectra

keyword
https://www.readbyqxmd.com/read/29148081/synthesis-antitumor-activity-evaluation-and-dna-binding-study-of-coumarin-based-agents
#1
Kamilia M Amin, Aly M Taha, Riham F George, Nada M Mohamed, Fardous F Elsenduny
A novel series of coumarin-thiadiazole heterocycle derivatives was synthesized by the nucleophilic substitution reaction. The synthesized compounds were structurally verified by IR, (1) H NMR, (13) C NMR, mass spectra, and elemental analyses. The antitumor activity of the synthesized compounds was evaluated through DNA binding assays and the 60-cell line panel according to the US NCI-DTP protocol or a selection of human tumor cell lines: breast cancer (MCF-7), liver cancer (HepG-2), and colorectal cancer (HCT-116)...
November 17, 2017: Archiv der Pharmazie
https://www.readbyqxmd.com/read/29145436/scrambled-eggs-proteomic-portraits-and-novel-biomarkers-of-egg-quality-in-zebrafish-danio-rerio
#2
Ozlem Yilmaz, Amélie Patinote, Thao Vi Nguyen, Emmanuelle Com, Regis Lavigne, Charles Pineau, Craig V Sullivan, Julien Bobe
Egg quality is a complex biological trait and a major determinant of reproductive fitness in all animals. This study delivered the first proteomic portraits of egg quality in zebrafish, a leading biomedical model for early development. Egg batches of good and poor quality, evidenced by embryo survival for 24 h, were sampled immediately after spawning and used to create pooled or replicated sample sets whose protein extracts were subjected to different levels of fractionation before liquid chromatography and tandem mass spectrometry...
2017: PloS One
https://www.readbyqxmd.com/read/29145135/forced-and-long-term-degradation-assays-of-tenoxicam-piroxicam-and-meloxicam-in-river-water-degradation-products-and-adsorption-to-sediment
#3
Juan J Jiménez, Beatriz E Muñoz, María I Sánchez, Rafael Pardo
The fate of the pharmaceutical drugs tenoxicam, piroxicam and meloxicam in river water is evaluated here for first time. So, biological, photochemical and thermal degradation assays have been conducted to estimate their degradation rates and know their degradation products. Results indicated that the direct sunlight irradiation, without any protection, promoted a fast degradation of the oxicams while the chemical reactions in solution were less important. The biological degradation in water was negligible except for tenoxicam in whose case its influence was scarce...
October 25, 2017: Chemosphere
https://www.readbyqxmd.com/read/29144587/characterization-of-complex-heterogeneous-lipid-a-samples-using-hplc-ms-ms-technique-iii-positive-ion-mode-tandem-mass-spectrometry-to-reveal-phosphorylation-and-acylation-patterns-of-lipid-a
#4
Viktor Sándor, Anikó Kilár, Ferenc Kilár, Béla Kocsis, Ágnes Dörnyei
In this study, we report the detailed analysis of the fragmentation patterns of positively charged lipid A species based on their tandem mass spectra obtained under low-energy collision-induced dissociation conditions of an electrospray quadrupole time-of-flight mass spectrometers. The tandem mass spectrometry experiments were performed after the separation of the compounds with a reversed-phase high performance liquid chromatography method. We found that both, phosphorylated and nonphosphorylated lipid A molecules can be readily ionized in the positive-ion mode by adduct formation with triethylamine added to the eluent...
November 16, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/29144418/nmr-based-identification-of-metabolites-in-polar-and-non-polar-extracts-of-avian-liver
#5
Fariba Fathi, Antonio Brun, Katherine H Rott, Paulo Falco Cobra, Marco Tonelli, Hamid R Eghbalnia, Enrique Caviedes-Vidal, William H Karasov, John L Markley
Metabolites present in liver provide important clues regarding the physiological state of an organism. The aim of this work was to evaluate a protocol for high-throughput NMR-based analysis of polar and non-polar metabolites from a small quantity of liver tissue. We extracted the tissue with a methanol/chloroform/water mixture and isolated the polar metabolites from the methanol/water layer and the non-polar metabolites from the chloroform layer. Following drying, we re-solubilized the fractions for analysis with a 600 MHz NMR spectrometer equipped with a 1...
November 16, 2017: Metabolites
https://www.readbyqxmd.com/read/29144133/inducing-secondary-metabolite-production-by-combined-culture-of-talaromyces-aculeatus-and-penicillium-variabile
#6
Zhenzhen Zhang, Xueqian He, Guojian Zhang, Qian Che, Tianjiao Zhu, Qianqun Gu, Dehai Li
Four new polyketides, penitalarins A-C (1-3) and nafuredin B (4), together with the known biogenetically related nafuredin A (5) were isolated from a mixed culture of a deep-sea-derived fungus Talaromyces aculeatus and a mangrove-derived fungus Penicillium variabile. Liquid chromatography/mass spectrometry analysis showed that none of compounds 1-5 was produced by either of the two fungi when cultured alone under the same condition. The structures of 1-4, including absolute configurations, were deduced based on the interpretation of MS, NMR data, and time-dependent density functional theory calculations of specific electronic circular dichroism spectra...
November 16, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/29143968/correlating-the-vibrational-spectra-of-structurally-related-molecules-a-spectroscopic-measure-of-similarity
#7
Yunwen Tao, Wenli Zou, Dieter Cremer, Elfi Kraka
Using catastrophe theory and the concept of a mutation path, an algorithm is developed that leads to the direct correlation of the normal vibrational modes of two structurally related molecules. The mutation path is defined by weighted incremental changes in mass and geometry of the molecules in question, which are successively applied to mutate a molecule into a structurally related molecule and thus continuously converting their normal vibrational spectra from one into the other. Correlation diagrams are generated that accurately relate the normal vibrational modes to each other by utilizing mode-mode overlap criteria and resolving allowed and avoided crossings of vibrational eigenstates...
November 16, 2017: Journal of Computational Chemistry
https://www.readbyqxmd.com/read/29143271/collision-induced-dissociation-of-deprotonated-peptides-relative-abundance-of-side-chain-neutral-losses-residue-specific-product-ions-and-comparison-with-protonated-peptides
#8
Yuxue Liang, Pedatsur Neta, Xiaoyu Yang, Stephen E Stein
High-accuracy MS/MS spectra of deprotonated ions of 390 dipeptides and 137 peptides with three to six residues are studied. Many amino acid residues undergo neutral losses from their side chains. The most abundant is the loss of acetaldehyde from threonine. The abundance of losses from the side chains of other amino acids is estimated relative to that of threonine. While some amino acids lose the whole side chain, others lose only part of it, and some exhibit two or more different losses. Side-chain neutral losses are less abundant in the spectra of protonated peptides, being significant mainly for methionine and arginine...
November 15, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/29143270/an-efficient-computer-aided-structural-elucidation-strategy-for-mixtures-using-an-iterative-dynamic-programming-algorithm
#9
Bo-Han Su, Meng-Yu Shen, Yeu-Chern Harn, San-Yuan Wang, Alioune Schurz, Chieh Lin, Olivia A Lin, Yufeng J Tseng
The identification of chemical structures in natural product mixtures is an important task in drug discovery but is still a challenging problem, as structural elucidation is a time-consuming process and is limited by the available mass spectra of known natural products. Computer-aided structure elucidation (CASE) strategies seek to automatically propose a list of possible chemical structures in mixtures by utilizing chromatographic and spectroscopic methods. However, current CASE tools still cannot automatically solve structures for experienced natural product chemists...
November 15, 2017: Journal of Cheminformatics
https://www.readbyqxmd.com/read/29142996/selective-phosphatidylcholine-double-bond-fragmentation-and-localisation-using-patern%C3%A3-b%C3%A3-chi-reactions-and-ultraviolet-photodissociation
#10
Fabian Wäldchen, Simon Becher, Patrick Esch, Mario Kompauer, Sven Heiles
The effect of double bond functionalisation for selective double bond localisation by ultraviolet photodissociation of phosphatidylcholines is investigated. Paternò-Büchi reactions in nanoESI emitter tips enable attachment of acetophenone to double bonds of unsaturated phosphatidylcholines after 100 s of 254 nm light irradiation with about 50-80% reaction yield. Functionalized phosphatidylcholines dissociate upon 266 nm irradiation yielding double bond selective fragment ions in contrast to results for ultraviolet photodissociation of unmodified lipids...
November 16, 2017: Analyst
https://www.readbyqxmd.com/read/29142823/investigation-of-useful-carbon-tracers-for-13-c-metabolic-flux-analysis-of-escherichia-coli-by-considering-five-experimentally-determined-flux-distributions
#11
Kousuke Maeda, Nobuyuki Okahashi, Yoshihiro Toya, Fumio Matsuda, Hiroshi Shimizu
The (13)C-MFA experiments require an optimal design since the precision or confidence intervals of the estimated flux levels depends on factors such as the composition of (13)C-labeled carbon sources, as well as the metabolic flux distribution of interest. In this study, useful compositions of (13)C-labeled glucose for (13)C-metabolic flux analysis ((13)C-MFA) of Escherichia coli are investigated using a computer simulation of the stable isotope labeling experiment. Following the generation of artificial mass spectra datasets of amino acid fragments using five literature-reported flux distributions of E...
December 2016: Metabolic Engineering Communications
https://www.readbyqxmd.com/read/29139026/structural-elucidation-of-novel-biomarkers-of-known-metabolic-disorders-based-on-multistage-fragmentation-mass-spectra
#12
Jan Václavík, Karlien L M Coene, Ivo Vrobel, Lukáš Najdekr, David Friedecký, Radana Karlíková, Lucie Mádrová, Aleksanteri Petsalo, Udo F H Engelke, Annemiek van Wegberg, Leo A J Kluijtmans, Tomáš Adam, Ron A Wevers
Specific diagnostic markers are the key to effective diagnosis and treatment of inborn errors of metabolism (IEM). Untargeted metabolomics allows for the identification of potential novel diagnostic biomarkers. Current separation techniques coupled to high-resolution mass spectrometry provide a powerful tool for structural elucidation of unknown compounds in complex biological matrices. This is a proof-of-concept study testing this methodology to determine the molecular structure of as yet uncharacterized m/z signals that were significantly increased in plasma samples from patients with phenylketonuria and 3-hydroxy-3-methylglutaryl-CoA lyase deficiency...
November 14, 2017: Journal of Inherited Metabolic Disease
https://www.readbyqxmd.com/read/29138467/bacillus-classification-based-on-matrix-assisted-laser-desorption-ionization-time-of-flight-mass-spectrometry-effects-of-culture-conditions
#13
Lin-Jie Shu, Yu-Liang Yang
Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a reliable and rapid technique applied widely in the identification and classification of microbes. MALDI-TOF MS has been used to identify many endospore-forming Bacillus species; however, endospores affect the identification accuracy when using MALDI-TOF MS because they change the protein composition of samples. Since culture conditions directly influence endospore formation and Bacillus growth, in this study we clarified how culture conditions influence the classification of Bacillus species by using MALDI-TOF MS...
November 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29137126/carbon-nanotubes-effect-on-mitochondrial-oxygen-flux-dynamics-polarography-experimental-study-and-machine-learning-models-using-star-graph-trace-invariants-of-raman-spectra
#14
Michael González-Durruthy, Jose M Monserrat, Bakhtiyor Rasulev, Gerardo M Casañola-Martín, José María Barreiro Sorrivas, Sergio Paraíso-Medina, Víctor Maojo, Humberto González-Díaz, Alejandro Pazos, Cristian R Munteanu
This study presents the impact of carbon nanotubes (CNTs) on mitochondrial oxygen mass flux (Jm) under three experimental conditions. New experimental results and a new methodology are reported for the first time and they are based on CNT Raman spectra star graph transform (spectral moments) and perturbation theory. The experimental measures of Jm showed that no tested CNT family can inhibit the oxygen consumption profiles of mitochondria. The best model for the prediction of Jm for other CNTs was provided by random forest using eight features, obtaining test R-squared (R²) of 0...
November 11, 2017: Nanomaterials
https://www.readbyqxmd.com/read/29136904/a-light-up-fluorescent-probe-for-citrate-detection-based-on-bispyridinum-amides-with-aggregation-induced-emission-feature
#15
Chenchen Liu, Yandi Hang, Tao Jiang, Ji Yang, Xiao Zhang, Jianli Hua
Citrate is an important intermediate in the citric acid cycle, a vital metabolic pathway for animals, plants and bacteria. It is of great significance to detect its levels in human beings because several diseases may cause the abnormal of citrate. In this paper, a new turn-on fluorescent sensor (TPE-Py) using the classic tetraphenylethylene (TPE) as the aggregation-induced emission (AIE) fluorophore and bipyridinium-based amides as the recognition receptor has been synthesized for the detection of citrate. The probe exhibits good selectivity and sensitivity to citrate with a relatively low detection limit (1...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136881/monitoring-of-tablet-coating-processes-with-colored-coatings
#16
Shirin Barimani, Peter Kleinebudde
Endpoints of coating processes for colored tablets were determined using in-line Raman spectroscopy. Coatings were performed with six commercially available formulations of pink, yellow, red, beige, green and blue color. The coatings were comprising pigments and/or dyes, some causing fluorescence and interfering the Raman signal. Using non-contact optics, a Raman probe was used as process analytical technology (PAT) tool, and acquired spectra were correlated to the sprayed mass of aqueous coating suspension...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136874/a-rapid-detection-method-for-policy-sensitive-amines-real-time-supervision
#17
Haixu Zhang, Jinian Shu, Bo Yang, Peng Zhang, Pengkun Ma
Many organic amines that comprise a benzene ring are policy-sensitive because of their toxicity and links to social harm. However, to date, detection of such compounds mainly relies on offline methods. This study proposes an online pptv (parts per trillion by volume) level of detection method for amines, using the recently-built vacuum ultraviolet photoionization mass spectrometer (VUV-PIMS) combined with a new doping technique. Thus, the dichloromethane doping-assisted photoionization mass spectra of aniline, benzylamine, phenethylamine, amphetamine, and their structural isomers were recorded...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136280/transitqa-a-new-method-for-transit-dosimetry-of-tomotherapy-patients
#18
Olivier Pisaturo, Frédéric Miéville, Pierre-Alain Tercier, Abdelkarim Said Allal
PURPOSE: TransitQA is an innovative method for Tomotherapy transit dosimetry using the on-board detector (OBD). Our previously published model for Tomotherapy treatment plan verification (AirQA) has been enhanced to take into account patient and couch transmission. AirQA estimates the OBD signal during irradiation with nothing in the beam path from the leaf control sinogram, allowing us to check whether the planned treatment is correctly delivered by the machine. TransitQA allows us to check the treatment delivery with the patient on the couch, potentially showing the effects of changes in the patient anatomy and delivery errors...
November 14, 2017: Medical Physics
https://www.readbyqxmd.com/read/29135232/confocal-raman-microscopy-for-the-determination-of-protein-and-quaternary-ammonium-ion-loadings-in-biocatalytic-membranes-for-electrochemical-energy-conversion-and-storage
#19
Rong Cai, Sofiene Abdellaoui, Jay P Kitt, Cullen Irvine, Joel Harris, Shelley D Minteer, Carol Korzeniewski
The need to immobilize active enzyme, while ensuring high rates of substrate turnover and electronic charge transfer with an electrode, is a centrally important challenge in the field of bioelectrocatalysis. In this work, we demonstrate the use of confocal Raman microscopy as a tool for quantitation and molecular-scale structural characterization of ionomers and proteins within biocatalytic membranes to aid in the development of energy efficient biofuel cells. A set of recently available short side chain Aquivion ionomers spanning a range of equivalent weight (EW) suitable for enzyme immobilization was investigated...
November 14, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29134766/comparative-analyses-of-data-independent-acquisition-mass-spectrometric-approaches-dia-wisim-dia-and-untargeted-dia
#20
Frank Koopmans, Jenny T C Ho, August B Smit, Ka Wan Li
Data independent acquisition (DIA) is an emerging technology for quantitative proteomics. Current DIA focusses on the identification and quantitation of fragment ions that are generated from multiple peptides contained in the same selection-window of several to tens of m/z. An alternative approach is WiSIM-DIA, which combines conventional DIA with wide-SIM (wide-selected ion monitoring) windows to partition the precursor m/z space to produce high quality precursor ion chromatograms. However WiSIM-DIA has been under-explored; it remains unclear if it is a viable alternative to DIA...
November 14, 2017: Proteomics
keyword
keyword
86994
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"