Synthesis of 3‐(Pyridin‐4‐Ylmethyl)‐4‐Substituted‐1,2,4‐Triazoline‐5‐Thione

The reaction of the hydrazide of pyridine‐4‐acetic acid with isothiocyanate gave thiosemicarbazide derivatives respectively. Further cyclization with 2% NaOH led to the formation of 4‐substituted 3‐(pyridin‐4‐ylmethyl)‐1,2,4‐triazoline‐5‐thione and 3‐(pyridin‐4‐ylmethyl)‐1,2,4‐triazoline‐5‐thione. The structures of all new products were confirmed by analytical and spectroscopic methods.     

Characterization of genetic variants of human serum transferrin by isoelectric focusing: comparison between conventional and immobilized pH gradients, and application to a protocol for paternity testing

The polymorphism of transferrin (Tf) is currently being studied by isoelectric focusing in carrier ampholyte-generated pH gradients, carrier ampholyte-separator pH gradients or in immobilized pH gradients. Details for obtaining reproducible results with each of the three procedures are outlined. The effectiveness of pretreatment of serum samples with ferrous/ferric salts is discussed, and incubation times optimized after spectrophotometric measurement of the monoferric Tf conversion. Most of the presently available commercial batches of carrier ampholytes do not reliably discriminate the six common TfC subtypes. Resolution of C1, C3 and C2 was achieved by adding 20 to 90 mM HEPES slab gels prepared with various carrier ampholytes. Isoelectric focusing in carrier ampholyte-separator pH gradients cannot be recommended as a standard typing procedure because the results strongly depend on the batch of carrier ampholytes. Tf subtype resolution was only achieved by using isoelectric focusing in immobilized pH gradients with pH slopes reliably reproducible from one experiment to another. Two major shortcomings of immobilized pH gradients are a marked tendency to protein precipitation at the application site and an interaction of proteins with the charged matrix. A protocol for Tf subtyping in immobilized pH gradients is described, based on prior desialylation of samples instead of pretreatment with iron. Sample entry into the matrix was optimized by addition of 5 mM Tris to the gels, and initially running them at low voltage. Recommendations are provided for the application of Tf typing for paternity testing.     

Focusing of Fe3O4 nanoparticles using a rotating magnetic field in various environments

The paper shows the application of a new method – Magnetic Nanoparticles Focusing 3D, MNF-3D – for focusing of magnetic nanoparticles at any point in a three-dimensional space between the rotating magnet system. The results of focusing process of nanoparticles in water, human blood, human serum and polyurethane sponge are presented. Additionally, blood flow was also considered. The effectiveness of nanoparticle focusing was monitored optically and quantitatively by electron spin resonance method. The method enabled focusing of magnetic nanoparticles within a few minutes in different environments. A good efficiency of focusing process was observed for all the samples.     

Free Radicals, Salicylic Acid and Mycotoxins in Asparagus After Inoculation with Fusarium proliferatum and F. oxysporum

Electron paramagnetic resonance was used to monitor free radicals and paramagnetic species like Fe, Mn, Cu generation, stability and status in Asparagus officinalis infected by common pathogens Fusarium proliferatum and F. oxysporum. Occurrence of F. proliferatum and F. oxysporum, level of free radicals and other paramagnetic species, as well as salicylic acid and mycotoxins content in roots and stems of seedlings were estimated on the second and fourth week after inoculation. In the first term free and total salicylic acid contents were related to free radicals level in stem (P?=?0.010 and P?=?0.033, respectively). Concentration of Fe(3+) ions in porphyrin complexes (g?=?2.3, g?=?2.9) was related to the species of pathogen. There was no significant difference between Mn(2+) concentrations in stem samples; however, the level of free radicals in samples inoculated with F. proliferatum was significantly higher when compared to F. oxysporum.     

Probing hot and dense laser-induced plasmas with ultrafast XUV pulses

In this Letter, we demonstrate the instantaneous creation of a hot solid-density plasma generated by focusing an intense femtosecond, high temporal contrast laser on an ultrathin foil (100 nm) in the 10(18) W/cm2 intensity range. The use of high-order harmonics generated in a gas jet, providing a probe beam of sufficiently short wavelengths to penetrate such a medium, enables the study of the dynamics of this plasma on the 100 fs time scale. The comparison of the transmission of two successive harmonics permits us to determine the electronic density and the temperature with accuracies better than 15%, never achieved up to this date in the regime of laser pulses at relativistic intensity.     

High order harmonic generation by non-linear reflection of a pedestal-free intense laser pulse on a plasma

We demonstrate the influence of the prepulses and ASE of ultrashort pulses interacting with a solid target by addressing the direct comparison of the harmonic spectra generated by reflection onto a solid target with and without the introduction of a plasma mirror system. Harmonics up to the 20th of the fundamental of the Ti-Sa laser are clearly visible in a situation free from any plasma expansion. PACS 42.65. Ky; 52.38.-r; 52.38.Ph; 52.50.Jm     

DFT studies on tautomeric preferences of 1-(pyridin-2-yl)-4-(quinolin-2-yl)butane-2,3-dione in the gas phase and in solution

Density functional theory (DFT) calculations show that in vacuum such α-diketone as 1-(pyridin-2-yl)-4-(quinolin-2-yl)butane-2,3-dione is much less stable than its enolimine–enaminone ((1Z,3Z)-3-hydroxy-4-(pyridin-2-yl)-1-(quinolin-2(1H)-ylidene)but-3-en-2-one) and dienaminone tautomers ((1Z,3Z)-1-(pyridin-2-yl)-4-(quinolin-2-yl)buta-1,3-diene-2,3-diol). Other its tautomers (multiple basic and acidic centers in their molecules enable multiple proton transfer to take place) are even more labile. Strength of the intramolecular hydrogen bonds and aromatic character of the (quasi)rings [proved by the Harmonic Oscillator Model of Aromaticity (HOMA) index] in their molecules were found to be responsible for the observed tautomeric preferences. Polar and basic solvent disfavors and favors the enolimine and enaminone tautomers, respectively.     

DFT studies on tautomeric preferences. Part 3: Proton transfer in 2-(8-acylquinolin-2-yl)-1,3-diones

8-Acetyl- and 8-benzoyl-2-(quinolin-2-yl) derivatives of 1,3-diketones were studied from point of view of their tautomeric preferences. Effective electron delocalization and strong hydrogen bonds were found to be responsible for high stability of the enaminone form (the most stable tautomer). Density functional theory (DFT) calculations prove that enolimine and ketimine species are less favored. Contribution of the zwitterionic resonance structures to the enaminone form is most significant in 2-(quinolin-2(1H)-ylidene)-2H-indene-1,3-dione derivatives. Formation of the bifurcated hydrogen bonds was found to take place only in 8-acetyl derivatives. One of these bonds is of the RAHB (Resonance Assisted Hydrogen Bond) type. There is a steric interaction of the pyridine β-hydrogen and carbonyl oxygen atoms in the enaminone tautomers.     

Influence of laser diode wavelength tunability on the range, resolution and repeatability of interferometric distance measurement

The coherence length of a single mode laser diode (LD) can reach more than 10 m. It allows the application of this source of light to interferometric distance measurement, with a measurement range of several meters. However, the LD's wavelength tunability, which is a result of the dependence of the lasing wavelength on the injection current, prevents the realization of the theoretically possible metrological parameters of the interferometer. In this study, we analyze the influence of a low-frequency signal disturbance, e.g., noise or disturbing modulation inherent to the injection current of the LD, on the repeatability and measurement range of an LD interferometer used for displacement measurements. Both the measurement range and the resolution of the interferometer are found to be highly limited by this factor.