- 标题
- 摘要
- 关键词
- 实验方案
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Mitochondria-Targeting Identification of a Fluorescent Apoptosis-Triggering Molecule by Mass Spectrometry Unravels Drug Tracking
摘要： The real-time tracking of localization and dynamics of small molecules in organelles helps to understand their function and lock their potential targets at the subcellular resolution. To identify the mitochondria-targeting effect of small molecules (NA-17 and NA-2a) in cancer cells, we used mass spectrometry to study the distribution and enrichment of small molecules in mitochondria and the residual cytoplasm, which enables to trace action process of therapeutic molecules. Colocalization analysis with an image-guided way suggests that both NA-17 and NA-2a have mitochondria-targeting effect. However, Mass Spectrometry (MS) analysis reveals that only NA-2a has mitochondria-targeting and enrichment effect, whereas NA-17 only distributes in the residual cytoplasm. A combination of mitochondria imaging, immunoblotting, and MS analysis in mitochondria indicate that NA-17 neither have the ability to enter mitochondria directly nor possess mitochondria-targeting effect. Further studies reveal that NA-17 could not enter mitochondria even though mitochondrial permeability has changed after NA-17 treatment in cells, evident by the ROS generation and cytochrome C release. In the process of cellular metabolism, NA-17 itself is firmly locked in the cytoplasm during the metabolic process, and its metabolites containing fluorophores could enrich in mitochondria for cell-imaging. Our present studies furnish new insights into drug metabolism process.
关键词： small molecule,mitochondria-targeting,mass spectrometry,drug tracking
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - New Silicon Crystals for a Redefined Kilogram and Mole: Isotopic Composition of the First Two Crystals
摘要： The isotopic compositions (molar mass, M) of the first and new silicon crystals highly enriched in 28Si (> 99.99 %) used for the determination of the Avogadro constant were measured using a high resolution multicollector ICP mass spectrometer and applying a modified isotope dilution mass spectrometry technique. Relative uncertainties urel(M) < 1 × 10-9 were obtained: a reduction by almost three orders of magnitude in ten years. This study compares the homogeneities in M(Si) of the first “AVO28” crystal and the first crystal (Si28-23Pr11) of the “Kilogram-2” project.
关键词： isotopic composition,enriched silicon,Avogadro constant,mass spectrometry,“Kilogram-2” project,homogeneity
更新于2025-09-10 09:29:36
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?Lab on a Chip“; Lab on a Chip;
摘要： Background. Miniaturization has not only driven microelectronics and generated new unforeseen options but has also dramatically changed sensors and analytics. Developments. The Lab on a Chip (LOC) technology enables laboratory processes to run fully automated in canals in the micrometre range. The biggest challenge for LOC is to keep production costs low despite miniaturization and application-specific design. If this is achieved medical laboratory analyses can usually be carried out faster and with less hands on time. This explains why LOCs are already integrated into many laboratory instruments and why point-of-care testing (POCT) can no longer be imagined without it. New markers, such as in liquid biopsies and measurement techniques, such as Raman spectroscopy and mass spectroscopy, create further potentials that will enable faster and more specific laboratory analyses to be made using LOC technology. Conclusion. The LOC technology has the potential of changing the medical practice especially in cases when the central laboratory is not available or is unable to provide results fast enough.
关键词： Laboratory diagnostics,Mass spectrometry,Point-of-care testing,Spectrum analysis, Raman,Microfluidics
更新于2025-09-10 09:29:36
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Simulation Study of the Beam Trajectory Effect on the Magnetic Field Distribution of a Duoplasmatron
摘要： Recently, a gas interface system was developed for accelerator mass spectrometry with a cesium sputtering ion source. A gaseous ion source was proposed and designed to eliminate the solidification and graphitization process in radiocarbon dating. A simulation study of the ion source for a gas sample analysis system was conducted to investigate the characteristics of the ion source when different anode shapes were used, and the results are reported in this paper. The use of different anode shapes revealed the influence of magnetic field penetration on the plasma within the expansion cup. An axial magnetic field constrains the discharge, producing greater ionization density. The ion beam trajectories from the ion source were calculated using the SIMION program to examine the dependence of the changes in the magnetic field distribution on the shape of the ion source’s anode.
关键词： Accelerator mass spectrometry,Ion source,Beam trajectory
更新于2025-09-10 09:29:36
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Discriminating Normal Regions within Cancerous Hen Ovarian Tissue Using Multivariate Hyperspectral Image Analysis
摘要： Identification of subregions under different pathological conditions on cancerous tissue is of great significance for understanding cancer progression and metastasis. Infrared matrix-assisted laser desorption electrospray ionization mass spectrometry (IR-MALDESI-MS) can be potentially used for the diagnostic purpose since it can monitor spatial distribution and abundance of metabolites and lipids in biological tissues. However, the large size and high dimensionality of hyperspectral data make analysis and interpretation challenging. To overcome these barriers, multivariate methods were applied to IR-MALDESI data for the first time, aiming at efficiently resolving mass spectral images, from which these results were then used to identify normal regions within cancerous tissue.
关键词： Mass Spectrometry Imaging,Multivariate curve resolution-Alternating Least Squares,IR-MALDESI,Ovarian Cancer,Principle Component Analysis
更新于2025-09-10 09:29:36
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Reference Module in Chemistry, Molecular Sciences and Chemical Engineering || Photoionization
摘要： The ionization of analyte molecules is of vital importance to mass spectrometric analysis because mass spectrometry takes only ions as the object for analysis. The most commonly used ionization source in mass spectrometry is electron-impact (EI) ionization source with electrons impacting to analyte with an energy of 70 eV. The kinetic energy of 70 eV is much higher than the ionization energy of organic molecules, and the ionization process approaches the maximal ionization efficiency. Thus, a large number of fragment peaks are usually observed in an EI mass spectrum. These fragments act as fingerprints of molecules, which can be used for identification of unknown molecules by searching EI-MS library, for example NIST Mass Spectral Library. This statistically based identification is particularly convenient and effective when analyzing a single component, for example a preseparated analyte by GC. However, there are many cases that analytes cannot be preseparated, for example very active components in a reaction, or fast on-line observation of evolving analytes. Consequently, the extensive fragmentation by EI-MS turns to a severe disadvantage: if each compound of a mixture produces a certain amount of fragment peaks, serious interference can be made, which will bring muscular obstacles to peak assignment. The best strategy is to use a “soft” ionization source with high selectivity. Here, “soft” means fragment-free or fragment-controllable.
关键词： SPI,Photoionization,APPI,REMPI,VUV Lamps,Synchrotron Radiation,Lasers,Mass Spectrometry
更新于2025-09-10 09:29:36
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A Fluorescent Silver(I) Carbene Complex with Anticancer Properties: Synthesis, Characterization and Biological Studies
摘要： The silver(I) NHC (N-heterocyclic carbene) complex bis(1-(anthracen-9-ylmethyl)-3-ethylimidazol-2-ylidene) chloride, ([Ag(EIA)2]Cl) hereafter, bearing two anthracenyl fluorescent probes has been synthesized and characterised. [Ag(EIA)2]Cl is stable in organic solvents and under physiological-like conditions, and shows in vitro potent cytotoxic effects toward human SH-SY5Y neuroblastoma cells. The interactions of [Ag(EIA)2]Cl with a few model biological targets have been studied here as well as its ability to be internalized in cells. The in vitro anticancer activity is apparently related to the level of drug internalisation. Notably, [Ag(EIA)2]Cl does not react with a few model proteins, but is capable to bind the C-terminal dodecapeptide of thioredoxin reductase hTrxR(488-499). Binding occurs through an unconventional process leading to covalent binding of one or two carbene ligands to the C-terminal dodecapeptide with concomitant release of the silver cation. This mode of interaction, to the best of our knowledge, is reported here for the first time for Ag(NHC)2 complexes; consequently, a potent enzyme inhibition is measured.
关键词： thioredoxin reductase,fluorescence,mass spectrometry,anticancer drugs,silver carbene complexes
更新于2025-09-10 09:29:36
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Correlated Materials Characterization via Multimodal Chemical and Functional Imaging
摘要： Multimodal chemical imaging simultaneously offers high resolution chemical and physical information with nanoscale, and in select cases atomic resolution. By coupling modalities that collect physical and chemical information, we can address scientific problems in biological systems, battery and fuel cell research, catalysis, pharmaceuticals, photovoltaics, medicine and many others. The combined systems enable local correlation of material properties with chemical makeup, making fundamental questions in how chemistry and structure drive functionality approachable. In this review we present recent progress and offer a perspective for chemical imaging used to characterize a variety of samples by a number of platforms. Specifically, we present cases in infrared and Raman spectroscopies combined with scanning probe microscopy; optical microscopy and mass spectrometry; nonlinear optical microscopy; and finally, ion, electron and probe microscopies with mass spectrometry. We also discuss the challenges associated with the use of data originated by the combinatorial hardware, analysis, and machine learning as well as processing tools necessary for interpretation of multidimensional data acquired from multimodal studies.
关键词： raman spectroscopy,ion microscopy,nonlinear optical microscopy,mass spectrometry,electron microscopy,infrared spectroscopy,chemical imaging,scanning probe microscopy,data analytics,optical microscopy
更新于2025-09-10 09:29:36
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Coulomb explosion imaging of CH <sub/>3</sub> I and CH <sub/>2</sub> ClI photodissociation dynamics
摘要： The photodissociation dynamics of CH3I and CH2ClI at 272 nm were investigated by time-resolved Coulomb explosion imaging, with an intense non-resonant 815 nm probe pulse. Fragment ion momenta over a wide m/z range were recorded simultaneously by coupling a velocity map imaging spectrometer with a pixel imaging mass spectrometry camera. For both molecules, delay-dependent pump-probe features were assigned to ultraviolet-induced carbon-iodine bond cleavage followed by Coulomb explosion. Multi-mass imaging also allowed the sequential cleavage of both carbon-halogen bonds in CH2ClI to be investigated. Furthermore, delay-dependent relative fragment momenta of a pair of ions were directly determined using recoil-frame covariance analysis. These results are complementary to conventional velocity map imaging experiments and demonstrate the application of time-resolved Coulomb explosion imaging to photoinduced real-time molecular motion.
关键词： pixel imaging mass spectrometry,time-resolved,CH3I,velocity map imaging,photodissociation dynamics,Coulomb explosion imaging,CH2ClI
更新于2025-09-10 09:29:36
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Pre-Processing MALDI/TOF Mass Spectra by Using Geena 2
摘要： Geena 2 is a tool for filtering, averaging, and aligning MALDI/TOF mass spectra, designed to assist scientists in the analysis of high volumes of data and support them for comparative studies. Three web interfaces are available with different levels of complexity. In this manuscript, we explain how to use Geena 2 with these three interfaces to perform analyses of one’s own data. Two support protocols showing how to check the example input file and how to create an input file with own data are also presented.
关键词： spectra alignment,mass spectrometry,pre-processing,MALDI/TOF
更新于2025-09-09 09:28:46