A straightforward synthesis of indazolo[3,2-a]isoquinolin-6-amines

4-Substituted 1-bromoisoquinolin-3-amines were subjected to Suzuki coupling with o-nitrophenylboronic acid to yield 1-(2-nitrophenyl) isoquinolinamines, which participated in Cadogan cyclization with triethyl phosphite under microwave irradiation in a sealed vial to yield fluorescent indazolo[3,2-a]isoquinolin-6-amines. The new compounds were also functionalized by transformation of the amino group.     

Development of split–splitless PTV large-volume injection for analytes covering a wide boiling point range

A programmed-temperature vaporiser (PTV)–large-volume injection (LVI) method with a two-stage evaporation process was developed capable of effectively introducing analytes covering a wide boiling-point range (from that of n-nonane to that of n-tetracontane). The method uses speed-controlled sample introduction (50 µL) and a simple PTV setup with Peltier Cooling. Besides, an important cause of discrimination of high-boiling compounds in LVI was identified. The method was successfully applied to simplify the sample preparation in the extractable petroleum hydrocarbon analysis of water and soil samples. The method proved to be resistant to matrix contamination. Linearity was tested between 0.01 and 20 µg mL^?1. The correlation coefficients ranged from 0.996 to 0.999. The relative standard deviation calculated from five parallel runs was 2.73%. The major advantage of the method is its simplicity making it an attainable choice for smaller environmental laboratories.     

Using the 186-keV peak for 226Ra activity concentration determination in Hungarian coal-slag samples by gamma-ray spectroscopy

The uranium isotopic abundance and the ²³⁸U–²²⁶Ra secular equilibrium were determined in nine Hungarian coal slag samples. The ²²⁶Ra activity concentration was measured based on the radon decay products and also the ²²⁶Ra peak at 186 keV. Secular equilibrium existed in eight samples, whereas one sample showed a slight disequilibrium. The direct and fast measurement using only the 186 keV peak was validated which can be used after measuring the uranium isotopic ratio and verifying the ²³⁸U–²²⁶Ra secular equilibrium. This method can be used to measure the ²²⁶Ra content of high number of samples from the same geochemical background.     

Glycan Side Reaction May Compromise ETD-Based Glycopeptide Identification

Tris(hydroxymethyl)aminomethane (Tris) is one of the most frequently used buffer ingredients. Among other things, it is recommended and is usually used for lectin-based affinity enrichment of glycopeptides. Here we report that sialic acid, a common ‘capping’ unit in both N- and O-linked glycans may react with this chemical, and this side reaction may compromise glycopeptide identification when ETD spectra are the only MS/MS data used in the database search. We show that the modification may alter N- as well as O-linked glycans, the Tris-derivative is still prone to fragmentation both in ‘beam-type’ CID (HCD) and ETD experiments, at the same time—since the acidic carboxyl group was ‘neutralized’—it will display a different retention time than its unmodified counterpart. We also suggest solutions that—when incorporated into existing search engines—may significantly improve the reliability of glycopeptide assignments.

Ellipsometric characterization of nanocrystals in porous silicon

Porous silicon layers (PSLs) were prepared by electrochemical etching of p-type single-crystalline silicon (c-Si) wafers having different dopant concentrations to obtain systematically changing sizes of nanocrystals (walls). The microstructure of the porous material was characterized using spectroscopic ellipsometry with multi-layer effective medium approximation (EMA) models. The dielectric function of PSL is conventionally calculated using EMA mixtures of c-Si and voids. The porosity is described by the concentration of voids. Some PSL structures can be described only by adding fine-grained polycrystalline silicon (nc-Si) reference material to the EMA model. Modified model dielectric functions (MDF) of c-Si have been shown to fit composite materials containing nanocrystalline regions, either by fitting only the broadening parameter or also other parameters of the parametric oscillator in MDF. The broadening parameter correlates with the long-range order in the crystalline material, and, as a consequence, with the size of nanocrystals. EMA and MDF models were used to describe systematically changing nanostructure of PSLs. Volume fraction of nc-Si in EMA and broadening parameter in MDF provide information on the nanocrystal size. The longer-term goal of this work is to provide a method for the quantitative characterization of nanocrystal size using quick, sensitive and non-destructive optical techniques.     

Thermal stability of rat uterus during development

Summary The age dependence of thermal denaturation was monitored in rats anaesthetized after they're born at 7^th, 14^th, 21^st, 28^th, 35^thand 42^nddays. The samples were stored in rigor or physiological saline solution. The DSC scans in the early age groups show a low temperature exotherm (connective tissues: from gel to liquid crystal transition) and one endotherm (it is very probably the myosin). During further development the endotherms became more and more complex (due to the development of contractile system). At 42 days the scans seem to be similar to the adult ones. In the two buffers the endotherms markedly differ showing that the ATPase activity is present. In adult uterus, treated with nucleotides or estrogen, this activity significantly differs from the skeletal muscle. On the basis of our results we suppose, that the age dependent changes are decisive processes in the development of rat uterus.     

A new cyclization to fused pyrazoles tunable for pericyclic or pseudopericyclic route: an experimental and theoretical study

2-Pyrazinyl (2) and 3-pyridazinylketone arylhydrazones (6) and their benzologues undergo a ring closure reaction to yield pyrazolo[3,4- b]pyrazines (4) and pyrazolo[4,3- c]pyridazines (7), respectively, in acceptable to good yields. The reaction was found to be accelerated by using acidic or basic conditions. Quantum chemical calculations suggest the key step of the mechanism to be a direct cyclization; analysis of aromaticity based on computed magnetic properties revealed its medium-dependent pericyclic or pseudopericyclic character. The cyclization reaction has also been extended for the synthesis of related ring systems ( 9, 12, 14).     

Lattice location and dopant behavior of group II and VI elements implanted in silicon

Outdiffusion, lattice location and electrical behavior of Zn, Cd, Hg and Se, Te implanted into silicon at 50 keV were investigated by backscattering and channeling effect of 1 MeV He⁺ ions and by Hall effect and sheet resistivity measurements. All the species exhibited outdiffusion with thermal processing. A significant fraction of Zn, Cd and Hg, when implanted into a substrate of 350°C, occupied regular interstitial lattice sites, while 50–60 per cent of the Se and Te atoms were on substitutional lattice sites. Selenium implanted at room temperature and mercury implanted into a substrate of 350°C exhibited depth dependent lattice location. The implanted layers showed n-type behavior: the maximum value of number of carriers/cm² was less than the number of implanted ions/cm² in all cases. The highest electrical activity was observed for Se corresponding to 25 per cent of the substitutional component.     

Ion-beam mixing of Co-Si and Co-SiO2: A comparison between Monte Carlo simulations and experiments

Abstract

The reaction of thin Co films with Si and SiO₂ during ion-beam mixing with As and Ge was studied. Fluences and energies used were varied between 2-10¹⁴ and 5-10¹⁵ cm^?2, and 15 and 200 keV, respectively. Concentration profiles of As, Ge, and Co were measured by SIMS; cross-sectional TEM-analysis was applied in order to investigate the metal-silicon interface. By comparing theoretical and experimental profiles, it was possible to separate ballistic effects from thermal processes in the Co-Si system. All theoretical profiles were calculated using the dynamic Monte-Carlo simulation program T-DYN. In case of Co-SiO₂ interaction, it could be shown that the Co distribution in the oxide was only caused by recoil implantation and not by diffusion processes or reactions.