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https://www.readbyqxmd.com/read/28651045/photoinduced-charge-transfer-versus-fragmentation-pathways-in-lanthanum-cyclopentadienyl-complexes
#1
Yulun Han, Qingguo Meng, Bakhtiyor Rasulev, P Stanley May, Mary T Berry, Dmitri S Kilin
This study compares two competing pathways of photoexcitations in gas-phase metal-organic complexes: first, a sequence of phonon-assisted electronic transitions leading to dissipation of the energy of photoexcitations and second, a sequence of light-driven electronic transitions leading to photolysis. Phonon-assisted charge carrier dynamics is investigated by combination of the density matrix formalism and on-the-fly nonadiabatic couplings. Light-driven fragmentation is modeled by a time-dependent excited-state molecular dynamics (TDESMD) algorithm based on Rabi theory and principles similar to the trajectory surface hopping approximation...
June 26, 2017: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/28651041/interaction-of-vivo-acac-2-with-human-serum-transferrin-and-albumin
#2
João Costa Pessoa, Isabel Correia, Ielyzaveta Chorna, Isabel Cavaco, Somnath Roy, Maxim L Kuznetsov, Nádia Ribeiro, Gonçalo Justino, Fernanda Marques, Teresa Santos Silva, Marino Santos, Hugo M Santos, José L Capelo, James Doutch
[VO(acac)2] is a remarkable vanadium compound and has potential as a therapeutic drug. It is important to clarify how it is transported in blood, but the reports addressing its binding to serum proteins have been contradictory. We use several spectroscopic and mass spectrometric techniques (ESI and MALDI-TOF), small-angle X-ray scattering and size exclusion chromatography (SEC) to characterize solutions containing [VO(acac)2] and either human serum apotransferrin (apoHTF) or albumin (HSA). DFT and modeling protein calculations are carried out to disclose the type of binding to apoHTF...
June 26, 2017: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/28649586/data-from-salivary-gland-proteome-analysis-of-female-aedes-aegypti-linn
#3
Rakhi Dhawan, Ajeet Kumar Mohanty, Manish Kumar, Gourav Dey, Jayshree Advani, T S Keshava Prasad, Ashwani Kumar
Salivary gland proteins from female Aedes aegypti mosquito were extracted and analyzed on high-resolution mass spectrometry. Proteomic data was analysed using two search algorithms SEQUEST and Mascot, which results in acquisition of 83,836 spectra which were assigned to 5417 peptides belonging to 1208 proteins.These proteins were then assigned molecular functions and further analysis revealed biological processes they are involved in using Gene Ontology annotations. Several immunity related pathways were found to be enriched in salivary gland...
August 2017: Data in Brief
https://www.readbyqxmd.com/read/28648259/semisynthesis-and-spectral-characterization-of-5-methylpyranopelargonidin-and-4-methylfuropelargonidin-and-their-separation-and-detection-in-strawberry-fruit-wine
#4
Ondřej Kurka, Lukáš Kučera, Helena Pelantová, Marek Kuzma, Vladimír Havlíček, Petr Bednář
Condensation of anthocyanins and their aglycons with small organic molecules yields more stable natural dyes, e.g. pyranoanthocyanins arising spontaneously in various food products. Reaction of pelargonidin with acetone produces two isomeric anthocyanidin dyes - 5-methylpyranopelargonidin and 4-methylfuropelargonidin. A robust semipreparative liquid chromatographic method was developed to isolate both derivatives from a simple aged solution of pelargonidin in methanol: acetone: 37% aqueous hydrochloric acid (1:1:0...
June 17, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28648061/development-of-a-comprehensive-flavonoid-analysis-computational-tool-for-ultra-high-performance-liquid-chromatography-diode-array-detection-high-resolution-accurate-mass-mass-spectrometry-data
#5
Mengliang Zhang, Jianghao Sun, Pei Chen
Liquid Chromatography and mass spectrometry methods, especially ultra-high performance liquid chromatography coupled with diode array detection and high resolution accurate-mass multi-stage mass spectrometry (UHPLC-DAD-HRAM/MSn), have become the tool-of-the-trade for profiling flavonoids in foods. However, manually processing acquired UHPLC-DAD-HRAM/MSn data for flavonoid analysis is very challenging and highly expertise-dependent due to the complexities of the chemical structures of the flavonoids and the food matrices...
June 25, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28645066/hydrothermal-co-carbonization-of-sewage-sludge-and-pinewood-sawdust-for-nutrient-rich-hydrochar-production-synergistic-effects-and-products-characterization
#6
Xiaojuan Zhang, Lei Zhang, Aimin Li
The aim of this study is to explore the synergistic effects of hydrothermal co-carbonization of sewage sludge and pinewood sawdust on hydrochar production. Firstly, the effects of mixing ratios on hydrothermal carbonization were investigated, and then, the hydrochar was characterized by diverse analytical techniques. The mass balance results indicated that a significant synergistic enhancement occurred in terms of the increased hydrochar yield, organic and carbon retentions. By combining sewage sludge and pinewood sawdust at the mass ratio of 1:1, 58...
June 20, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28644981/chemical-profiling-and-antioxidant-evaluation-of-yangxinshi-tablet-by-hplc-esi-q-tof-ms-ms-combined-with-dpph-assay
#7
Junfeng Zhu, Xiaojiao Yi, Jinghui Zhang, Shuqing Chen, Yongjiang Wu
Yangxinshi Tablet (YXST) is a Chinese patent medicine commonly used to treat cardiovascular diseases. However, its detailed chemical basis and mechanisms of action have not been clarified. In this study, high performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (HPLC-ESI-Q-TOF-MS) was applied for comprehensive analysis of the chemical constituents in YXST. A total of 127 compounds, including 19 phenolic acids, 12 alkaloids, 51 flavanoids, 32 triterpenoids, 2 lignans, 2 phenylethanoid glycosides, 2 anthraquinones, 1 coumarin, and 6 other compounds, were identified or tentatively deduced by comparing their retention times and MS spectra with those of authentic standards or literature data...
June 15, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/28644913/supplement-2-for-the-2004-update-of-the-aapm-task-group-no-43-report-joint-recommendations-by-the-aapm-and-gec-estro
#8
Mark J Rivard, Facundo Ballester, Wayne M Butler, Larry A DeWerd, Geoffrey S Ibbott, Ali S Meigooni, Christopher S Melhus, Michael G Mitch, Ravinder Nath, Panagiotis Papagiannis
Since publication of the 2004 update to the American Association of Physicists in Medicine (AAPM) Task Group No. 43 Report (TG-43U1) and its 2007 supplement (TG-43U1S1), several new low-energy photon-emitting brachytherapy sources have become available. Many of these sources have satisfied the AAPM prerequisites for routine clinical purposes and are posted on the Brachytherapy Seed Registry managed jointly by the AAPM and the Imaging and Radiation Oncology Core Houston Quality Assurance Center (IROC Houston)...
June 23, 2017: Medical Physics
https://www.readbyqxmd.com/read/28643516/untargeted-comprehensive-two-dimensional-liquid-chromatography-coupled-with-high-resolution-mass-spectrometry-analysis-of-rice-metabolome-using-multivariate-curve-resolution
#9
Meritxell Navarro-Reig, Joaquim Jaumot, Anna Baglai, Gabriel Vivó-Truyols, Peter J Schoenmakers, Romà Tauler
In this work, a new strategy for the chemometric analysis of LC×LC-HRMS data is proposed. This approach consists of a preliminary compression step along the MS spectral dimension based on the selection of the Regions of Interest (ROI), followed by a further data compression along the chromatographic dimension by wavelet transforms. In a secondary step, the Multivariate Curve Resolution Alternating Least Squares (MCR-ALS) method is applied to previously compressed data sets obtained in the simultaneous analysis of multiple LC×LC-HRMS chromatographic runs from multiple samples...
June 23, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28643153/a-3e8-scfv-cys-ir800-conjugate-targeting-tag-72-in-an-orthotopic-colorectal-cancer-model
#10
Li Gong, Haiming Ding, Nicholas E Long, Brandon J Sullivan, Edward W Martin, Thomas J Magliery, Michael F Tweedle
PURPOSE: Optical surgical navigation (OSN) will be a potent tool to help surgeons more accurately and efficiently remove tumors. The purpose of this study was to evaluate a novel humanized 3E8 antibody (3E8 MAb) fragment site-specifically conjugated with IR800, 3E8.scFv.Cys-IR800, as a potential OSN agent to target colorectal adenocarcinoma. PROCEDURES: An engineered single-chain variable fragment of 3E8 MAb (targeted to TAG-72), appending a C-terminal cysteine residue (3E8...
June 22, 2017: Molecular Imaging and Biology: MIB: the Official Publication of the Academy of Molecular Imaging
https://www.readbyqxmd.com/read/28642031/clustering-of-ms-2-spectra-using-unsupervised-methods-to-aid-the-identification-of-secondary-metabolites-from-pseudomonas-aeruginosa
#11
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/28641411/development-of-an-lc-hrms-metabolomics-method-with-high-specificity-for-metabolite-identification-using-all-ion-fragmentation-aif-acquisition
#12
Shama Naz, Hector Gallart-Ayala, Stacey Reinke, Caroline Mathon, Richard Blankley, Romanas Chaleckis, Craig Edward Wheelock
High-resolution mass spectrometry (HRMS)-based metabolomics approaches have made significant advances. However, metabolite identification is still a major challenge and significant bottleneck in translating metabolomics data into biological context. In the current study, a liquid chromatography (LC)-HRMS metabolomics method was developed using an all ion fragmentation (AIF) acquisition approach. In order to increase the specificity in metabolite annotation, four criteria were considered: i) accurate mass (AM), ii) retention time (RT), iii) MS/MS spectrum, and iv) product/precursor ion intensity ratios...
June 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28637909/rapid-differentiation-of-haemophilus-influenzae-and-haemophilus-haemolyticus-using-maldi-tof-mass-spectrometry-with-clinprotools-mass-spectra-analysis
#13
Jonathan H K Chen, Vincent C C Cheng, Chun-Pong Wong, Sally C Y Wong, Wing-Cheong Yam, Kwok-Yung Yuen
Haemophilus influenzae is associated with severe invasive disease, while Haemophilus haemolyticus is considered part of the commensal flora in the human respiratory tract. Although the addition of a custom mass spectra library into the matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) system could improve identification of these two species, the establishment of such a custom database is technically complicated and requires a large amount of resources, which most clinical laboratories cannot afford...
June 21, 2017: Journal of Clinical Microbiology
https://www.readbyqxmd.com/read/28637907/online-identification-of-fungi-using-maldi-tof-mass-spectrometry-validation-of-a-new-web-application
#14
A C Normand, P Becker, F Gabriel, C Cassagne, I Accoceberry, M Gari-Toussaint, L Hasseine, D De Geyter, D Pierard, I Surmont, F Djenad, J L Donnadieu, M Piarroux, S Ranque, M Hendrickx, R Piarroux
MALDI-TOF mass spectrometry has emerged as a reliable technique to identify molds involved in human diseases, including dermatophytes, provided that exhaustive reference databases are available. This study assessed an online identification application based on original algorithms and an extensive in-house reference database comprising 11,851 spectra (938 fungal species and 246 fungal genera).Validation criteria were established using an initial panel of 422 molds, including dermatophytes, previously identified via DNA sequencing (126 species)...
June 21, 2017: Journal of Clinical Microbiology
https://www.readbyqxmd.com/read/28636386/msviz-a-graphical-software-tool-for-in-depth-manual-validation-and-quantitation-of-post-translational-modifications
#15
Trinidad Martin Campos, Roman Mylonas, Alexandre Masselot, Patrice Waridel, Tanja Petricevic, Ioannis Xenarios, Manfredo Quadroni
Mass spectrometry (MS) has become the tool of choice for the large scale identification and quantitation of proteins and their post-translational modifications (PTMs). This development has been enabled by powerful software packages for the automated analysis of MS data. While data on PTM's of thousands of proteins can nowadays be readily obtained, fully deciphering the complexity and combinatorics of modification patterns even on a single protein often remains challenging. Moreover, functional investigation of PTMs on a protein of interest requires validation of the localization and the accurate quantitation of its changes across several conditions, tasks that often still require human evaluation...
June 21, 2017: Journal of Proteome Research
https://www.readbyqxmd.com/read/28634761/unveiling-the-compositional-variety-of-cardiolipins-in-rhodobacter-sphaeroides-by-liquid-chromatography-with-electrospray-ionization-and-multistage-collision-induced-dissociation-mass-spectrometry
#16
Sara Granafei, Ilario Losito, Massimo Trotta, Angela Agostiano, Francesco Palmisano, Tommaso R I Cataldi
Cardiolipins (CL) contained in the lipid extracts of the photosynthetic bacterium Rhodobacter sphaeroides (strain R26) were systematically characterized by reversed-phase liquid chromatography coupled to electrospray ionization mass spectrometry, performed in single (MS), tandem (MS/MS) and sequential (MS(3)) modes using a linear ion trap mass spectrometer. The total number of carbon atoms and C=C bonds of each CL and, subsequently, those related to each of the constituting phosphatidic acid (PA) units, along with the location of the latter on the central glycerol backbone, were inferred from MS and MS/MS data, respectively...
June 20, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28632988/solid-sampling-with-a-diode-laser-for-portable-ambient-mass-spectrometry
#17
Yeni P Yung, Raveendra Wickramasinghe, Anu Vaikkinen, Tiina Johanna Kauppila, Igor V Veryovkin, Luke Hanley
A handheld diode laser is implemented for solid sampling in portable ambient mass spectrometry (MS). Specifically, a pseudo-continuous wave battery-powered surgical laser diode is employed for portable laser diode thermal desorption (LDTD) at 940 nm and compared with nanosecond pulsed laser ablation at 2940 nm. Postionization is achieved in both cases using atmospheric pressure photoionization (APPI). The laser ablation atmospheric pressure photoionization (LAAPPI) and LDTD-APPI mass spectra of sage leaves (Salvia officinalis) using a field-deployable quadrupole ion trap MS display many similar ion peaks, as do the mass spectra of membrane grown biofilms of Pseudomonas aeruginosa...
June 20, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28631783/ultrafast-charge-dynamics-in-glycine-induced-by-attosecond-pulses
#18
David Ayuso, Alicia Palacios, Piero Decleva, Fernando Martín
The combination of attosecond pump-probe techniques with mass spectrometry methods has recently led to the first experimental demonstration of ultrafast charge dynamics in a biomolecule, the amino acid phenylalanine [Calegari et al., Science, 2014, 346, 336]. Using an extension of the static-exchange density functional theory (DFT) method, the observed dynamics was explained as resulting from the coherent superposition of ionic states produced by the broadband attosecond pulse. Here, we have used the static-exchange DFT method to investigate charge migration induced by attosecond pulses in the glycine molecule...
June 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28631114/derivatization-of-dextran-for-multiply-charged-ion-formation-and-electrospray-ionization-time-of-flight-mass-spectrometric-analysis
#19
Jesus B Tapia, Hailey A J Hibbard, Melissa M Reynolds
We present the use of a simple, one-pot derivatization to allow the polysaccharide dextran to carry multiple positive charges, shifting its molecular weight distribution to a lower m/z range. We performed this derivatization because molecular weight measurements of polysaccharides by mass spectrometry are challenging because of their lack of readily ionizable groups. The absence of ionizable groups limits proton abstraction and suppresses proton adduction during the ionization process, producing mass spectra with predominantly singly charged metal adduct ions, thereby limiting the detection of large polysaccharides...
June 19, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28631113/fast-determination-of-ingredients-in-solid-pharmaceuticals-by-microwave-enhanced-in-source-decay-of-microwave-plasma-torch-mass-spectrometry
#20
Rui Su, Xinchen Wang, Changming Hou, Meiling Yang, Keke Huang, Huanwen Chen
Rapid qualitative and quantitative analysis of solid samples (e.g., pharmaceutical preparations) by using a small and low-resolution mass spectrometer without MS/MS function is still a challenge in ambient pressure ionization mass spectrometric analysis. Herein, a practically efficient method termed microwave-enhanced in-source decay (MEISD) using microwave plasma torch desorption ionization coupled with time-of-flight mass spectrometry (MPTDI-TOF MS) was developed for fast analysis of pharmaceutical tablets using a miniature TOF mass spectrometer without tandem mass function...
June 19, 2017: Journal of the American Society for Mass Spectrometry
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