Helianthus annuus (sunflower) displays non-glandular trichomes (NGT), capitate glandular trichomes (CGT), and linear glandular trichomes (LGT), which reveal different chemical compositions and locations in different plant tissues. With matrix-assisted laser desorption/ionization (MALDI) and laser desorption/ionization (LDI) mass spectrometry imaging (MSI) techniques, efficient methods were deve...

The low density hydrogen and helium in the IGM probed by QSO absorption lines is sensitive to the amplitude and spectral shape of the metagalactic UV background. We use realistic H I and He II Lyα forest spectra, constructed from state-of-the-art hydrodynamical simulations of a ΛCDM Universe, to confirm the reliability of using line profile fitting techniques to infer the ratio of the metagalac...

Efficient strategies are required to implement comprehensive suspect screening methods using high-resolution mass spectrometry within environmental monitoring campaigns. In this study, both liquid and gas chromatography time-of-flight mass spectrometry (LC-QTOF-MS and GC-QTOF-MS) were used to screen for >5000 target and suspect compounds in the Sacramento-San Joaquin River Delta in Northern Cal...

keto-enol tautomerism was investigated for ionized pyruvic acid using the dft(b3lyp) method and the larger basis sets [6-31++g(d,p), 6-311++g(3df, 3pd) and aug-cc-pvdz]. change of the tautomeric preference was observed when going from the neutral to ionized tautomeric mixture. ionization favors the enolization process (ketoenol) of pyruvic acid, whereas the ketonization (ketoenol) is preferred ...

background: the heterogeneous composition of the human body presents numerous tissue types and cavities with widely differing radiologic properties. the aim of the present work was to develop a low cost homogeneous and heterogeneous phantom and the absorbed dose were measured by ionization chamber for different radiotherapy treatment techniques and compared with treatment planning system absorb...

a time-of-flight mass spectrometer (tof-ms) developed in our laboratory at isfahan university of technology is described here. the tof-ms instrument uses laser as the ionization source which provides an opportunity to investigate the ions formed in laser ablation or desorption. the tof-ms has an ionization chamber containing an accelerator and an ion lens to focus the ions into a one meter line...

The recalculation of 1 fraction from a patient treatment plan on a phantom and subsequent measurements have become the norms for measurement-based verification, which combines the quality assurance recommendations that deal with the treatment planning system and the beam delivery system. This type of evaluation has prompted attention to measurement equipment and techniques. Ionization chambers ...

Online monitoring of the appearance of the intermediates and products during chemical reactions is helpful to understand reaction mechanisms. Various analytical tools including nuclear magnetic resonance spectroscopy, Raman spectroscopy and mass spectrometry (MS) have been employed for the study. MS is one of the most promising means among analytical tools that can provide information of mass-t...

Recent developments in mass spectrometry (MS) analyses have seen a concerted effort to reduce the complexity of analytical workflows through simplification (or removal) sample preparation and shortening run-to-run analysis times. Ambient ionization (AIMS) is an exemplar MS-based technology that has swiftly developed into popular powerful tool science. This increase interest demonstrable applica...