keyword
MENU ▼
Read by QxMD icon Read
search

Mass spectra

keyword
https://www.readbyqxmd.com/read/28088690/electrochemical-studies-of-dna-interaction-and-antimicrobial-activities-of-mn-ii-fe-iii-co-ii-and-ni-ii-schiff-base-tetraazamacrocyclic-complexes
#1
Anuj Kumar, Vinod Kumar Vashistha, Prashant Tevatia, Randhir Singh
Tetraazamacrocyclic complexes of Mn(II), Fe(III), Co(II) and Ni(II) have been synthesized by template method. These tetraazamacrocycles have been analyzed with various techniques like molar conductance, IR, UV-vis, mass spectral and cyclic voltammetric studies. On the basis of all these studies, octahedral geometry has been assigned to these tetraazamacrocyclic complexes. The DNA binding properties of these macrocyclic complexes have been investigated by electronic absorption spectra, fluorescence spectra, cyclic voltammetric and differential pulse voltammetric studies...
January 6, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28087976/the-role-of-diode-array-ultraviolet-detection-for-the-identification-of-synthetic-cathinones
#2
Walter F Rowe, Ioan Marginean, Stephanie Carnes, Ira S Lurie
The utility of diode array UV detection for aiding in the identification of synthetic cathinones, including different sub classes and positional isomers is presented. For 35 synthetic cathinones' unique UV spectra are obtained for seven sub classes including mostly beta ketones, where position and type of substitution on benzene rings give rise to differences in UV maxima and relative intensity of the spectral bands. This aspect is key to distinguishing positional isomers which contain differences in R substitution (mono and di) around the benzene ring, which provides complementary information to electron ionization mass spectrometry, where the latter technique cannot distinguish between these types of positional isomers...
January 14, 2017: Drug Testing and Analysis
https://www.readbyqxmd.com/read/28086860/nicotiana-attenuata-data-hub-nadh-an-integrative-platform-for-exploring-genomic-transcriptomic-and-metabolomic-data-in-wild-tobacco
#3
Thomas Brockmöller, Zhihao Ling, Dapeng Li, Emmanuel Gaquerel, Ian T Baldwin, Shuqing Xu
BACKGROUND: Nicotiana attenuata (coyote tobacco) is an ecological model for studying plant-environment interactions and plant gene function under real-world conditions. During the last decade, large amounts of genomic, transcriptomic and metabolomic data have been generated with this plant which has provided new insights into how native plants interact with herbivores, pollinators and microbes. However, an integrative and open access platform that allows for the efficient mining of these -omics data remained unavailable until now...
January 13, 2017: BMC Genomics
https://www.readbyqxmd.com/read/28086263/observation-of-the-ring-puckering-vibrational-mode-in-thietane-cation
#4
Yu Ran Lee, Chung Bin Park, Jiye Hwang, Bongjune Sung, Hong Lae Kim, Chan Ho Kwon
We have measured the high-resolution vibrational spectra of a thietane (trimethylene sulfide) cation in the gas phase by employing the vacuum ultraviolet mass-analyzed threshold ionization (VUV-MATI) spectroscopic technique. Peaks in the low frequency region of the observed MATI spectrum of thietane originate from a progression of the ring puckering vibrational mode (typical in small heterocyclic molecules), which is successfully reproduced by quantum chemical calculations with one-dimensional (1D) symmetric double-well potentials along the ring puckering coordinates on both the S0 and D0 states, the ground electronic states of neutral and cation of thietane, respectively...
January 13, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28079220/facile-pentagon-formation-in-the-dissociation-of-polyaromatics
#5
Arjen J de Haas, Jos Oomens, Jordy Bouwman
Energetic processing of gaseous polycyclic aromatic hydrocarbons (PAHs) plays a pivotal role in the chemistries of inter- and circumstellar environments, certain planetary atmospheres, and also in the chemistry of combustion and soot formation. Although the precursor PAH species have been extensively characterized, the products from these gaseous breakdown reactions have received far less attention. It has been particularly challenging to accurately determine their molecular structure in gas-phase experiments, where comparisons against theoretical modeling are best made...
January 12, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28078420/comprehensive-polyphenol-profiling-of-a-strawberry-extract-fragaria-%C3%A3-ananassa-by-ultra-high-performance-liquid-chromatography-coupled-with-high-resolution-mass-spectrometry
#6
Giorgia La Barbera, Anna Laura Capriotti, Chiara Cavaliere, Susy Piovesana, Roberto Samperi, Riccardo Zenezini Chiozzi, Aldo Laganà
The aim of metabolic untargeted profiling is to detect and identify unknown compounds in a biological matrix to achieve the most comprehensive metabolic coverage. In phytochemical mixtures, however, the complexity of the sample could present significant difficulties in compound identification. In this case, the optimization of both the chromatographic and the mass-spectrometric conditions is supposed to be crucial for the detection and identification of the largest number of compounds. In this work, a systematic investigation of different chromatographic and mass-spectrometric conditions is presented to achieve a comprehensive untargeted profiling of a strawberry extract (Fragaria × ananassa)...
January 11, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28077870/the-role-of-interfacial-lipids-in-stabilizing-membrane-protein-oligomers
#7
Kallol Gupta, Joseph A C Donlan, Jonathan T S Hopper, Povilas Uzdavinys, Michael Landreh, Weston B Struwe, David Drew, Andrew J Baldwin, Phillip J Stansfeld, Carol V Robinson
Oligomerization of membrane proteins in response to lipid binding has a critical role in many cell-signalling pathways but is often difficult to define or predict. Here we report the development of a mass spectrometry platform to determine simultaneously the presence of interfacial lipids and oligomeric stability and to uncover how lipids act as key regulators of membrane-protein association. Evaluation of oligomeric strength for a dataset of 125 α-helical oligomeric membrane proteins reveals an absence of interfacial lipids in the mass spectra of 12 membrane proteins with high oligomeric stability...
January 11, 2017: Nature
https://www.readbyqxmd.com/read/28074602/direct-maldi-ms-analysis-of-the-disulfide-bonds-in-peptide-using-thiosalicylic-acid-as-a-reactive-matrix
#8
Daiki Asakawa, Issey Osaka
The ability of a thiol-containing molecule, thiosalicylic acid (TSA), to function as a reactive matrix for matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis of peptides has been investigated. Although TSA has reducing characteristics, the use of TSA did not cause a reduction-induced MALDI in-source decay (MALDI-ISD), probably because of the weak interactions between the thiol group in TSA and the carboxyl oxygen in the peptide. In contrast, when peptides containing disulfide bonds were analyzed by MALDI with TSA as the matrix, the disulfide bond was partially cleaved owing to the reaction with TSA, producing TSA adducted peptides...
January 10, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28074361/partially-deuterated-samples-of-het-s-218-289-fibrils-assignment-and-deuterium-isotope-effect
#9
Albert A Smith, Francesco Ravotti, Emilie Testori, Riccardo Cadalbert, Matthias Ernst, Anja Böckmann, Beat H Meier
Fast magic-angle spinning and partial sample deuteration allows direct detection of (1)H in solid-state NMR, yielding significant gains in mass sensitivity. In order to further analyze the spectra, (1)H detection requires assignment of the (1)H resonances. In this work, resonance assignments of backbone H(N) and Hα are presented for HET-s(218-289) fibrils, based on the existing assignment of Cα, Cβ, C', and N resonances. The samples used are partially deuterated for higher spectral resolution, and the shifts in resonance frequencies of Cα and Cβ due to the deuterium isotope effect are investigated...
January 10, 2017: Journal of Biomolecular NMR
https://www.readbyqxmd.com/read/28071906/single-conformation-spectroscopy-of-suberoylanilide-hydroxamic-acid-saha-a-molecule-bites-its-tail
#10
Di Zhang, Karl N Blodgett, Xiao Zhu, Timothy S Zwier
Suberoylanilide hydroxamic acid (C6H5NHCO(CH2)6CONHOH, SAHA) is a histone deacetylase inhibitor that causes growth arrest and differentiation of many tumor types and is an approved drug for the treatment of cancer. With a hydrogen-bonding amide group adjacent to its phenyl ring "head", and a hydroxamic acid group at the "tail" end of a C6 alkyl chain linker, SAHA possesses an interesting potential energy landscape to be probed by single-conformation methods. The alkyl chain's preference for extended structures is in competition with tail-to-head (T-H) or head-to-tail (H-T) hydrogen bonds between the amide and hydroxamic acid groups...
January 10, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28071717/tryptophan-and-non-tryptophan-fluorescence-of-the-eye-lens-proteins-provides-diagnostics-of-cataract-at-the-molecular-level
#11
Anna Gakamsky, Rory R Duncan, Nicola M Howarth, Baljean Dhillon, Kim K Buttenschön, Daniel J Daly, Dmitry Gakamsky
The chemical nature of the non-tryptophan (non-Trp) fluorescence of porcine and human eye lens proteins was identified by Mass Spectrometry (MS) and Fluorescence Steady-State and Lifetime spectroscopy as post-translational modifications (PTM) of Trp and Arg amino acid residues. Fluorescence intensity profiles measured along the optical axis of human eye lenses with age-related nuclear cataract showed increasing concentration of fluorescent PTM towards the lens centre in accord with the increased optical density in the lens nucleolus...
January 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28068884/evaluation-of-protein-spectra-cluster-analysis-for-streptococcus-spp-identification-from-various-swine-clinical-samples
#12
Carlos E C Matajira, Luisa Z Moreno, Vasco T M Gomes, Ana Paula S Silva, Renan E Mesquita, Daniela S Doto, Franco F Calderaro, Fernando N de Souza, Ana Paula G Christ, Maria Inês Z Sato, Andrea M Moreno
Traditional microbiological methods enable genus-level identification of Streptococcus spp. isolates. However, as the species of this genus show broad phenotypic variation, species-level identification or even differentiation within the genus is difficult. Herein we report the evaluation of protein spectra cluster analysis for the identification of Streptococcus species associated with disease in swine by means of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). A total of 250 S...
January 1, 2017: Journal of Veterinary Diagnostic Investigation
https://www.readbyqxmd.com/read/28068569/quantification-of-ph-dependent-speciation-of-organic-compounds-with-spectroscopy-and-chemometrics
#13
Thomas Ritschel, Kai Uwe Totsche
Fluorescence and UV/Vis spectra of aqueous solutions with numerous organic compounds are a superposition of single spectra of the chemical species present. Thus, an isolation of individual spectra with chemometrics is required for their quantification. We investigated UV/Vis spectra and fluorescence excitation-emission matrices of vanillic acid, salicylic acid, phenoxyacetic acid and phthalic acid with positive matrix factorization (PMF) and non-negativity constrained parallel factor analysis (PARAFAC) in combination with the law of mass action...
December 30, 2016: Chemosphere
https://www.readbyqxmd.com/read/28067464/analysis-of-six-neuro-enhancing-phenidate-analogs
#14
Helge Klare, Jörg M Neudörfl, Simon D Brandt, Elisabeth Mischler, Sigrid Meier-Giebing, Kathrin Deluweit, Folker Westphal, Tim Laussmann
Six collected phenidates, i.e. 4-methylmethylphenidate, 3,4-dichloromethylphenidate, ethylphenidate, 3,4-dichloroethylphenidate, ethylnaphthidate and N-benzyl-ethylphenidate were fully characterized by means of X-ray, NMR, GC-MS, ESI-MS(2) , ATR-FT-IR and GC solid-state IR analysis. Crystallography revealed the exclusive presence of the threo-configuration. Steric crowding induced by N-benzyl substitution at the piperidine moiety prompted an adoption of an unexpected axial positioning of substituents on the piperidine moiety in the crystal state as opposed to the exclusive equatorial positioning encountered in N-unsubstituted phenidate analogs...
January 9, 2017: Drug Testing and Analysis
https://www.readbyqxmd.com/read/28066547/holographic-direct-pulsed-laser-writing-of-two-dimensional-nanostructures
#15
Bader AlQattan, Haider Butt, Aydin Sabouri, Ali K Yetisen, Rajib Ahmed, Nasim Mahmoodi
The development of accurate and rapid techniques to produce nanophotonic structures is essential in data storage, sensors, and spectroscopy. Existing bottom-up and top-down approaches to fabricate nanophotonic devices are high cost and time consuming, limiting their mass manufacturing and practical applications. Here, we demonstrate a strategy to rapidly create 25-40 nm thick 1/2D Au-Ti nanopatterns using holographic direct laser interference patterning (DLIP). Pulses of an Nd:YAG laser (1064 nm) in holographic Denisyuk reflection mode were used to create ablative interference fringes...
December 4, 2016: RSC Advances
https://www.readbyqxmd.com/read/28065892/rapid-detection-of-the-plasmid-mediated-quinolone-resistance-determinant-aac-6-ib-cr-in-enterobacteriaceae-by-maldi-tof-ms-analysis
#16
Marina Oviaño, Jose Manuel Rodríguez-Martínez, Álvaro Pascual, Germán Bou
OBJECTIVES: Rapid detection of the plasmid-mediated quinolone resistance determinant AAC(6')-Ib-cr in Enterobacteriaceae by measuring acetyltransferase activity against fluoroquinolones by MALDI-TOF MS analysis. METHODS: The presence of the AAC(6')-Ib-cr enzyme was determined by MS by measuring the acetyltransferase activity of a collection of 81 isogenic Escherichia coli control strains [10 carrying the AAC(6')-Ib-cr enzyme during exposure to ciprofloxacin, norfloxacin and levofloxacin] and further analysis of 36 clinical isolates [25 carrying the AAC(6')-Ib-cr enzyme in addition to different combinations of quinolone resistance mechanisms]...
January 8, 2017: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/28065752/covalent-immobilization-of-trypsin-onto-modified-magnetite-nanoparticles-and-its-application-for-casein-digestion
#17
Keziban Atacan, Bekir Çakıroğlu, Mahmut Özacar
The immobilization method consists of the production magnetite nanoparticles (Fe3O4) by solvothermal treatment of FeCl3 and sodium acetate (NaAc) in the presence of ethylene glycol. Subsequently, the surface of magnetite nanoparticles was modified with a well-known polyphenol tannic acid. Trypsin was covalently immobilized on the tannic acid modified magnetite nanoparticles after exposing the modified nanoparticles to pH 9.4. Then, tryptic digestion of casein by free and immobilized trypsin was carried out for 13h and 1h, respectively...
January 5, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28064392/chemical-composition-structural-properties-and-source-apportionment-of-organic-macromolecules-in-atmospheric-pm10-in-a-coastal-city-of-southeast-china
#18
Yanting Chen, Wenjiao Du, Jinsheng Chen, Youwei Hong, Jinping Zhao, Lingling Xu, Hang Xiao
Particulate matter (PM10) associated with the fractions of organic macromolecules, including humic acid (HA), kerogen + black carbon (KB), and black carbon (BC), was determined during summer and winter at urban and suburban sites in a coastal city of southeast China. The organic macromolecules were characterized by elemental analysis (EA), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR), and their sources were identified by using stable carbon/nitrogen isotope (δ(13)C/δ(15)N) and the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) Model...
January 7, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28063268/evaluation-of-the-quality-of-herbal-teas-by-dart-tof-ms
#19
Jana Prchalová, František Kovařík, Aleš Rajchl
The paper focuses on the optimization, settings and validation of direct analysis in real time (DART) coupled with time of flight detector (TOF) when used for the evaluation of the quality of selected herbal teas (fennel, chamomile, nettle, linden, peppermint, thyme, lemon balm, marigold, sage, rose hip, St. John's Wort). The ionization mode, the optimal ionization temperature and the type of solvent for sample extraction were optimized. The characteristic compounds of the analysed herbal teas (glycosides, flavonoids, phenolic and terpenic substances, such as chamazulene, anethole, menthol, thymol, salviol, hypericin etc...
January 7, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28061743/shotgun-proteomics-of-the-barley-seed-proteome
#20
Ramamurthy Mahalingam
BACKGROUND: Barley seed proteins are of prime importance to the brewing industry, human and animal nutrition and in plant breeding for cultivar identification. To obtain comprehensive proteomic data from seeds, total protein from a two-rowed (Conrad) and a six-rowed (Lacey) barley cultivar were precipitated in acetone, digested in-solution, and the resulting peptides were analyzed by nano-liquid chromatography coupled with tandem mass spectrometry. RESULTS: The raw mass spectra data searched against Uniprot's Barley database using in-house Mascot search engine identified 1168 unique proteins...
January 6, 2017: BMC Genomics
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"