Mössbauer spectra of equilibrated ordinary chondrites consist of two doublets due to paramagnetic iron present in olivines and pyroxenes and two sextets due to magnetically ordered iron present in metallic phases and troilite. The spectral areas of the different mineralogical phases found by Mössbauer spectroscopy in meteorites are proportional to the number of iron atoms in this mineralogical phase. This property of Mössbauer spectra can be the basis for constructing a method for the classification of ordinary chondrites. This idea was first explored at the Mössbauer Laboratory in Kanpur. This group suggested a qualitative method based on 2‐dimensional plots of Mössbauer spectral areas and thus classified properly some meteorites. We constructed a quantitative method using Mössbauer spectral areas, multidimensional discriminant analysis, and Mahalanobis distance (4M method) to determine the probability of a meteorite to be of type H, L, or LL. Based on 59 Mössbauer spectra, we calculated by the 4M method, Scluster, the level of similarity of the Goronyo meteorite to the clusters. On the plot of ferrosilite versus fayalite, the point representing Goronyo is located on the border between H and L areas. Calculated by the 4M method, the meteorite Goronyo is 32% similar to type H, 75% to type L, and 11% to type LL. Additional mineralogical analyses suggested that the Goronyo meteorite would be classified as type L, although it was originally reported as type H in the Meteoritical Bulletin Database.

In current studies we use the oligonucleotides based on c-myc sequence: CCC CAC CCT CCC CAC CCT CCC C (cmyc22) and CCC CAC CCT CCC CAC CCT CCC CA (cmyc22A) functionalized by pyrene moieties at both termini. Results of the circular dichroism (CD), UV absorption melting experiments, and steady-state fluorescence measurements of pyrene-modified i-motifs as well as their unlabeled precursors are presented and discussed here. The pyrene labels have a remarkable influence on i-motif stability which was deduced from CD spectra and confirmed by UV melting experiments. Both probes emit fluorescence band of pyrene monomer with intensity decreasing upon pH lowering.Electronic supplementary materialThe online version of this article (doi:10.1007/s10895-013-1184-z) contains supplementary material, which is available to authorized users.

The aim of our studies was to check the usefulness of Mössbauer spectroscopy for preliminary classification of ordinary chondrites. Mössbauer spectra of 50 samples of ordinary chondrites (type LL, L and H) obtained at room temperature were analyzed. 35 Mössbauer spectra were obtained in our laboratory, the other spectra were taken from the literature. The conclusion of our study was, that the most useful way for the preliminary classification of the ordinary chondrites is the application of two types of plots based on the data obtained by Mössbauer spectroscopy. One type of these plots is a linear plot which was used for the identification of the samples which are unrepresentative. The second type of these plots is a plot of "spectral area of the olivine" vs "spectral area of the metallic phase". This last one was used for the identification of two unknown meteorites.

Cytosine-rich nucleic acids undergo pH-stimulated structural transitions leading to formation of an i-motif architecture at an acidic pH. Thus, i-motifs are good foundation for designing simple pH-sensitive fluorescent probes. We report here steady-state and time-resolved fluorescence studies of pyrene-labeled probes based on RET sequence: C4GC4GC4GC4TA (RET21), AC4GC4GC4GC4TA (RET21A) and C4GC4GC4GC4T (RET20). Comparative studies with single-and double-labeled i-motif probes were carried out. For each probe, we have measured fluorescence spectra and decays for emission wavelength of 390 nm over a wide range of pH (from 4.0 to 8.0). Effect of the oligonucleotide sequence and the number of pyrene labels on the spectral characteristics of probes were discussed.

Strength of laser welded joints of polypropylene composites V Votrubec, P Hisem, L Vinšová et al. -Hardness variation of welded boron steel using continuous wave (CW) and pulse wave (PW) mode of fiber laser K I Yaakob, M Ishak, S R A Idris et al. Abstract. The author considers the gas-dynamic action of the shielding gas jet during consumable electrode welding on the processes in the welding area and properties of the weld joints produced from alloyed high-strength steel 30HGSA. The results of the research on the gas-dynamic action of the jet on the process of consumable electrode welding are provided. It was established that the method of consumable electrode welding with double-jet gas shielding ensures regulated gas dynamics in the welding area and allows controlling the electrode metal transfer, the chemical composition of the weld metal, stabilizing the process of welding and ensures stable high mechanic properties of the weld joints. Introduction.At the present time welding is applied for producing permanent joints of the widest range of metallic, nonmetallic and composite constructional materials under the conditions of earth atmosphere, World's ocean and aerospace. In spite of continuously growing application of light metal alloys, polymer and composite materials in construction, steel remains the basic constructional material. Consumable electrode welding in the atmosphere of shielding gases stays one of the main production methods in the process of developing the material basis of modern civilization.The history of the thermal processes determines the productivity of the basic metal and welding filler fusion, trend and completeness of the metallurgic processes in the weld pool, conditions of weld and heat-affected zone metal structure formation, performance characteristics of the weld joints [1][2][3][4][5].The shielding gas is normally used to protect the welding area from the harmful action of the air but, under certain conditions, it can become the instrument for controlling the processes in the weld zone and the properties of weld joints. A number of studies [6-13 and other] investigating the influence of the shielding gas flow upon the process of consumable electrode welding notice that increase in the gas flow rate is associated with improvement of the quality of the weld zone protection, weld formation, welding process stabilization, improvement of the weld metal properties. Increase of the shielding gas flow ensures increased hardness of the gas jet which is especially important when completing the welding works in an exposed position [2,6,10].