Mossbauer analysis of deformation dissolution of the products of cellular decomposition in high-nitrogen chromium manganese austenite steel

Methods of Mossbauer spectroscopy and electron microscopy analysis of high-nitrogen chromium manganese steel FeMn₂₂Cr₁₈N_0.8 have been used to investigate the processes of dissolution of the products of cellular decomposition in austenite matrix upon severe deformation under the conditions of dry sliding friction and shear under pressure in Bridgman anvils. Deformation-induced redistribution of nitrogen from the chromium nitrides to interstitial positions of the quenched and preliminary aged steel has been determined. According to the data of Mossbauer analysis the depth of dissolution of chromium nitrides and the increase of content of nitrogen in steel matrix upon friction is 10?μn and more. Aging decreases the amount of nitrogen which transfers to the solid solution under deformation. This is a factor of the enhanced adhesive wear in the aged samples.     

Synthesis and crystal structure of some phosphite,thiophosphite, and amidophosphite copper(I) halide complexes

Some Cu(I) halides complexes based on P(III) acid esters,{[(RE)₃PCuBr] (where E = O, N, S); R = n‐Pr, i‐Pr, Et₂N} were obtained and characterized using IR, ³¹P NMR spectroscopy, and single crystal X‐ray diffraction. The comparative structural characteristics of complexes with various donor atoms (E = O, N, S) are analyzed. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:483–489, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20459     

5-Amino-Substituted Derivatives of 4-Nitrofurazane: Synthesis,Structure, and Biological Activity

New amination reactions of 5-chloro-4-nitrobenzofurazane with different amines were studied. The reactions of 5-chloro-4-nitrobenzofurazane with 2,4,6-trichloro-, para-acetyl-, and para-carboxyethylanilines gave the products of aromatic nucleophilic substitution of the chlorine substituent in the nitrogenous heterocycle, the composition and structure of which was established by chemical, physical, and physicochemical methods and X-ray diffraction analysis. The thermal stability was studied by synchronous thermogravimetry and differential scanning calorimetry (TG?DSC). The synthesized compounds showed a high antibacterial and antimycotic activity against human and animal pathogenic microflora.     

Synthesis of Stable Diarylpalladium(II) Complexes: Detailed Study of the Aryl–Aryl Bond‐Forming Reductive Elimination

The synthesis of diarylpalladium(II) complexes by twofold aryl C?H bond activation was developed. These intermediates of oxidative cyclization reactions are stabilized by chelation with acetyl groups while still maintaining sufficient reactivity to study their reductive elimination. Four distinct triggers were found for the reductive elimination of these complexes to dibenzofurans and carbazoles. Thermal elimination occurs at very high temperatures, whereas ligand‐promoted and oxidatively induced reductive eliminations proceed readily at room temperature. Under these conditions, no isomerization occurs. In contrast, weak Brønsted acids, such as acetic acid, lead to a sequence of proto‐demetalation, isomerization to a κ³‐diarylpalladium(II) complex, and reductive elimination to non‐symmetrical cyclization products.     

3-nitro- and 3-bromo-3-nitroacrylates in reactions with phenyl azide

1,3-Dipolar cycloaddition of alkyl 3-nitro-and 3-bromo-3-nitroacrylates to phenyl azide gives regioisomeric alkyl 5(4)-nitro-1-phenyl-4,5-dihydro-1H-1,2,3-triazole-4(5)-carboxylates, the corresponding triazoles both with and without nitro group, and alkyl 3-nitro-1-phenylaziridine-2-carboxylates. Nitrotriazolecarboxylates were found to lose the ester moiety during chromatographic separation of the products on aluminum oxide. The structure of the products was determined on the basis of IR, ¹H NMR, and X-ray diffraction data.     

Chiral derivatives of titanium with terpene alcohols

A series of substituted alkoxy compounds of titanium were prepared by reactions of titanium isopropylate with 1-menthol, 1-borneol, (±)-isoborneol, and (-)-trans-3-hydroxymyrtanol. The specific rotation of the alcoholates was shown to be an additive function of the number of the terpene ligands. For titanium bornylates, the optical activity is a linear function of the degree of substitution. For trans-3-hydroxymyrtanol derivatives, an inversion of the optical rotation angle is observed along with an additive dependence of the optical activity on the degree of substitution.     

Gas-solid elution chromatography in a column with surface-layer biporous packing

The theory of gas-solid elution chromatography on surface-layer biporous packing was examined. The explicit analytical expressions for the dependences of HETP and retention time on the thickness of the surface porous layer were obtained. The use of the surface-layer packing makes it possible to increase the separation efficiency as compared to the conventional sorbents. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 340–342, February, 1999.     

Diagnostic Value of Short and Long Echo Time in <Superscript>1</Superscript>H-MRS for Patients with Multiple Sclerosis

The quality of the signal received from metabolites in ¹H-magnetic resonance spectroscopy (MRS) directly depends on physical parameters of the impulse sequence used, namely on Time of Echo (TE). We compare MRS (Achieva 3T PRESS ¹H-MRS (TE = 53 and 144 ms, TR = 2000 ms) data acquired in supraventricular white matter and medial cortex at two various TE (53 and 144 ms) for patients with the multiple sclerosis (25 patients with the confirmed diagnosis of relapsing-remitting multiple sclerosis and 20 patients with the diagnosis of secondary progressive multiple sclerosis) and control group (21 healthy volunteers, comparable on age), to evaluate advantages and disadvantages of these two Echo Time in clinical practice.