Rapid crack growth in a thermoelastic solid under mixed-mode thermomechanical loading

A two-dimensional steady-sate analysis of semi-infinite brittlecrack growth at a constant subcritical rate in an unboundedfully-coupled thermoelastic solid under mixed-mode thermomechanicalloading is made. The loading consists of normal and shear tractionsand heat fluxes applied as point sources (line loads in theout-of-plane direction). A related problem is solved exactly in an integral transformspace, and robust asymptotic forms used to reduce the originalproblem to a set of integral equations. The equations are partiallycoupled and exhibit operators of both Cauchy and Abel types,yet can be solved analytically. The temperature change field at a distance from the moving crackedge is then constructed, and its dominant term is found tobe controlled by the imposed heat fluxes. The role of this termis, indeed, enhanced if the heat fluxes serve to render thecrack as a net heat source/sink for the solid, as opposed tobeing a transmitter of heat across its plane. More generally,the influence of the thermoelastic coupling on this field, aswell as other functions, is found to increase with crack speed.     

Copper(I) and silver(I) complexes of 2-amino-1,3,4-thiadiazole and 2-ethylamino-1,3,4-thiadiazole

The following copper(I) and silver(I) complexes of 2-amino-1,3,4-thiadiazole (atz) and 2-ethylamino-1,3,4-thiadiazole (eatz) have been prepared and studied by conductometric, IR and Raman methods: CuXL(X = Cl, Br, I; L = atz, eatz), CuXL₃(X = ClO₄, NO₃; L = atz, eatz), AgClO₄·1.5atz·1/3 EtOH, AgNO₃·2.5atz, AgClO₄·3eatz, AgNO₃·eatz. The ligands are bonded through the amine nitrogen atoms with ν(MN) bands in the 520–410 cm^?1 region. The CuXL complexes have a trigonal (N, 2X_b) coordination with a probable weaker axial interaction. The CuXL₃ and AgCIO₄·3eatz complexes probably have a trigonal pyramidal (3N,O) coordination. In the atz complexes of silver perchlorate and nitrate some ligand molecules are bridging. The AgNO₃·2.5atz complex is likely to have a dimeric structure with tetrahedral coordination of the silver ion.     

Resveratrol-derived stilbenoids and biological activity evaluation of seed extracts of Cenchrus echinatus L

A phytochemical study of the ethyl acetate fractions from the partition of seeds and roots methanol extracts of Cenchrus echinatus L. led to the isolation of three resveratrol-derived stilbenoids: pallidol (1), carasiphenol C (2) and nepalensinol B (3). The results of a topic anti-inflammatory evaluation, DPPH assay and antiproliferative activity against adenocarcinoma cells (Caco 2) are described.     

Functionalized gold nanoparticles for ultrasensitive DNA detection

A major challenge in the area of DNA detection is the development of rapid methods that do not require polymerase chain reaction (PCR) amplification of the genetic sample. The PCR amplification step increases the cost of the assay, the complexity of the detection, and the quantity of DNA required for the assay. In this context, methods that are able to perform DNA analyses with ultrasensitivity have recently been investigated with the aim of developing new PCR-free detection protocols. Functionalized gold nanoparticles have played a central role in the development of such methods. Here, possibilities offered by functionalized gold nanoparticle in the ultrasensitive detection of DNA are discussed. The different functionalization protocols available for gold nanoparticles and the principal DNA detection methods that are able to detect DNA at the femtomolar to attomolar level are presented.     

Synthetic magnetic opals

We present studies of novel nanocomposites of BiNi impregnated into the structure of opals as well as inverse opals. Atomic force microscopy and high resolution elemental analyses show a highly ordered structure and uniform distribution of the BiNi filler in the matrix. These BiNi-based nanocomposites are found to exhibit distinct ferromagnetic-like ordering with transition temperature of about 675 K. As far as we know there exists no report in literature on any BiNi compound which is magnetic.     

Chromium (III) trihalide complexes of 4-aminobenzophenone

Summary The following chromium(III) complexes of 4-aminobenzophenone have been prepared and investigated by infrared and electronic spectra and magnetic susceptibility measurements: CrCl₃L, CrCl₃L₂ (pink and brown), CrCl₃L₃, CrCl₃L₆, CrBr₃L₂, CrBr₃L₃, CrBr₃L₄, CrBr₃L₆, CrBr₃L₇ and CrBr₃L₈. The CrBr₃ complexes were each isolated in a yellow and a red form. In the red CrBr₃ and in the yellow CrBr₃L₂ the ligand is bonded through the amine nitrogen. The CrCl₃ complexes are probably molecular complexes.