Ion detector of time-of-flight mass spectrometer with registration of leading and trailing edges.

The accuracy of the ion flight time measurement in the time-of-flight mass spectrometer is critical to achieving high resolution. The pulse amplitude variation of the detector pulses leads to the registration time spread at a given pulse detection threshold. This time spread can be eliminated by determining the position of the pulse apex.

Laser-Induced Ion Formation and Electron Emission from a Nanostructured Gold Surface at Laser Fluence below the Threshold for Plasma Formation.

The laser formation of positive and negative ions on a nanostructured metal surface is observed at laser fluence below the plasma formation threshold. The laser radiation energy dependences of the yield of positive and negative Au ions and charged clusters as well as electrons from the laser-induced nanostructures on the surface of gold are obtained at laser fluence below the plasma formation threshold using a pulsed laser with a wavelength of 355 nm and a pulse duration of 0.37 ns.

NMR assignments and secondary structure distribution of emfourin, a novel proteinaceous protease inhibitor.

Emfourin (M4in) from Serratia proteamaculans is a new proteinaceous inhibitor of protealysin-like proteases (PLPs), a subgroup of the well-known and widely represented metallopeptidase M4 family. Although the biological role of PLPs is debatable, data published indicate their involvement in pathogenesis, including bacterial invasion into eukaryotic cells, suppression of immune defense of some animals, and destruction of plant cell walls. Gene colocalization into a bicistronic operon observed for some PLPs and their inhibitors (as in the case of M4in) implies a mutually consistent functioning of both entities.

Synthesis and characterization of heteroleptic rare earth double-decker complexes involving tetradiazepinoporphyrazine and phthalocyanine macrocycles.

Reaction of (2,3,9,10,16,17,23,24-octabutylphthalocyaninato)lanthanide(iii) acetylacetonates (BuPcLn(acac), 1a-c, Ln = Lu (a), Eu (b), La (c)) with a tetrakis(5,7-bis(4-tert-butylphenyl)-6H-1,4-diazepino)[2,3-b,g,l,q]porphyrazine ligand (tBuPhDzPzH2, 2) produced sandwich compounds (tBuPhDzPz)Ln(BuPc) (3a-c), which represent the first heteroleptic double-deckers incorporating both Pc and DzPz decks. A combination of high-resolution mass spectrometry, UV-Vis/NIR, MCD, and 1H NMR spectroscopy, and square-wave voltammetry provided unambiguous characterization of target complexes 3 indicating that their spectral and electrochemical properties are generally intermediate with respect to their homoleptic relatives. Based on the data of solution-state 1H-1H NMR (COSY, NOESY) correlation spectroscopy supported by DFT calculations, a dimerization tendency of compounds 3 proportional to the Ln(iii) ion size was found.

Ionization of organic molecules with metal ions formed in the laser plasma.

A laser plasma ion source was used to ionize volatile organic compounds in a gas sample. The plasma was generated on a metal target in the intermediate vacuum region of ~0.3 Torr using a pulsed Nd:YAG laser with a wavelength of 1 μm.