Pr0.5Ca0.5Mn1−xCrxO3 (x= 0.015-0.05) undergoes an insulator-metal (I-M) transition below a temperature Tp driven by percolation of ferromagnetic metallic clusters in a charge ordered insulating matrix. Surprisingly, the I-M transition in these compounds is unstable against thermal cycling : Tp decreases and the resistivity at Tp increases upon temperature cycling between a starting temperature ...

kinetics of radical polymerizations of waterborne alkyd/acrylic hybrid resin via batch mini-emulsion technique was studied using redox initiators (tbhp/fe2+/edta/asac  and  tbhp/fe2+/edta/sfs) at relatively low temperatures and thermal initiators (bpo, kps and aibn) at higher temperatures to seek the most suitable initiator system. at the end of all reactions the unreacted monomer content was r...

The polymerization domain of phi29 DNA polymerase acquires a toroidal shape by means of an arch-like structure formed by the specific insertion TPR2 (Terminal Protein Region 2) and the thumb subdomain. TPR2 is connected to the fingers and palm subdomains through flexible regions, suggesting that it can undergo conformational changes. To examine whether such changes take place, we have construct...

exfoliated poly (chloromethyl styrene-co-styrene)-g-polyacrylonitryle/organo- modified montmorillonite [p(cmst-co-st)-g-pan/o-mmt] nanocomposite was synthesized through solution intercalation method by using atom transfer and nitroxide mediated radical polymerization. at first, poly (chloromethyl styrene-costyrene) copolymer was synthesized by nitroxide - mediated “living” free radical polyme...

The microcalorimetric studies on the polymerization of acrylonitrile with and without the thermal influence of polyacrylonitrile decomposition provide vital information on its thermal sensitivity and intrinsic safety. The present studies indicate that the exothermicity of polymerization and decomposition of polyacrylonitrile are kept under check by the self-regulatory role of the aqueous medium...

The first cationic main group tetrahydroborate complexes are reported. [Ca(BH(4))(THF)(5)][BPh(4)] and the charge neutral (Tp((t)Bu,Me))Ca(BH(4))(THF) are initiators for the living ring opening polymerization of rac-lactide, the latter producing PLA with high levels of heterotactic enrichment. These represent a new class of ROP initiators for main group metals.

In the present work, we have reported the in situ oxidation of manganese (II) acetate to MnO2 nanoparticles through the thermal plasma carbonized natural hydroxyapatite (MnO2/TP-NHAp) as a neoteric sustainable method. Interestingly, the thermal plasma-processed surface of the NHAp shows a great ability for oxidation of the manganese (II) without need of any external oxidizing agents. The cataly...

For the emergence of early life, the formation of biopolymers such as RNA is essential. However, the addition of nucleotide monomers to existing oligonucleotides requires millimolar concentrations. Even in such optimistic settings, no polymerization of RNA longer than about 20 bases could be demonstrated. How then could self-replicating ribozymes appear, for which recent experiments suggest a m...

a series of polystyrene hybrid nanocomposites have been fabricated with varying amounts of tio2 viz., 0, 0.5 and 1 % w/w along with 3% ts by in-situ polymerization method. the influence of surface modified tio2 nanoparticles on the thermal properties of ps matrix was examined using thermogravimetry and differential scanning calorimetry. thermal characteristics of the polystyrene/ts/tio2 hybrid ...