Semi-wet growth and characterization of multi-functional nano-engineered mixed metal oxides for industrial application

This review paper covers the low temperature wet growth of nano-engineered particles of ZnO-based mixed metal oxides, their growth mechanism, and characterization using X-ray diffraction, SEM, TEM and IR, UV–visible, and XPS spectral techniques. Main focus of this article is centered on low temperature semi-wet methods of synthesis that are suitable for large scale production of zinc oxide-based systems mixed with iron oxide, copper oxide, nickel oxide and cobalt oxide. These mixed metal oxides have broad industrial applications as catalyst, semiconductors, adsorbents, superconductors, electro-ceramics, and antifungal agents in addition to extensive applications in medicines. This paper discusses the low-cost and environment friendly synthesis of these mixed metal oxides, measurement of properties and applicability of these materials systems.     

Electrochemical determination of reduction potentials in glass-forming melts

Square-wave voltammetry (SWV) has been used to determine the reduction potentials of several multivalent elements in situ in an alkali borosilicate melt. Such reduction potentials measured at melt temperature were found to be proportional to the relative reduction potentials obtained from analyses of the quenched glasses. Accordingly, the redox state of the glass typically reflects the redox state of the melt. Although SWV is a sensitive tool for monitoring the total concentration of specific multivalent elements in the melt, the method does not directly monitor the redox state of the melt.     

Spherically symmetric inhomogeneous dust collapse in higher dimensional space-time and cosmic censorship hypothesis

We consider a collapsing spherically symmetric inhomogeneous dust cloud in higher dimensional space-time. We show that the central singularity of collapse can be a strong curvature or a weak curvature naked singularity depending on the initial density distribution.     

Synaptic depression and short-term habituation are located in the sensory part of the mammalian startle pathway

Background  

Short-term habituation of the startle response represents an elementary form of learning in mammals. The underlying mechanism is located within the primary startle pathway, presumably at sensory synapses on giant neurons in the caudal pontine reticular nucleus (PnC). Short trains of action potentials in sensory afferent fibers induce depression of synaptic responses in PnC giant neurons, a phenomenon that has been proposed to be the cellular correlate for short-term habituation. We address here the question whether both this synaptic depression and the short-term habituation of the startle response are localized at the presynaptic terminals of sensory afferents. If this is confirmed, it would imply that these processes take place prior to multimodal signal integration, rather than occurring at postsynaptic sites on PnC giant neurons that directly drive motor neurons.     

Synthesis of Pt(dpk)Cl(4) and the reversible hydration to Pt(dpk-O-OH)Cl(3).H-phenCl: X-ray, spectroscopic, and electrochemical characterization

We report on the synthesis of a platinum(IV) compound containing a di-2-pyridyl ketone (dpk) ligand that is stable both in its anhydrous form [Pt(dpk)Cl(4)] (1) and in its hydrated form [Pt(dpk-O-OH)Cl(3)].H-phenCl (2). The crystal structure of the hydrated form shows that one of the hydroxide groups from the resulting gem-diol has undergone a cyclometalation/condensation reaction resulting in an oxygen atom directly coordinated to the Pt(IV) center and the formation of H-phenCl. We correlate our physical data with predictions made by molecular modeling, and we propose an explanation for the unusual activity found for this dpk ketone. Spectroscopic and solubility studies are presented here, as well. Electrochemical studies of 1 indicate that it undergoes a highly irreversible reduction at a potential of about -0.45 V vs Ag(+)/Ag in CH(3)CN and that the irreversibility is likely due to an EC mechanism, the nature of which is currently under further investigation. Another distinct redox pair, apparently reversible, appears at a potential of about -1.1 V vs Ag(+)/Ag.     

Estimation of trace elements in some medicinal plants used in anti‐cancer drugs by PIXE

A trace elemental analysis was carried out in various parts of 12 anticancer medicinal plants, using the PIXE (particle‐induced X‐ray emission) technique. A 3‐MeV proton beam was used to excite the samples, and spectra were recorded using a Si (Li) detector. Data analysis was done using the GUPIX software. The elements Cl, K, Ca, Ti, V, Mn, Fe, Ni, Cu, Zn, Br and Sr were identified, and their concentrations estimated. The results of the present study provide justification for the usage of these medicinal plants in the development of anticancer drugs. Copyright © 2012 John Wiley & Sons, Ltd.