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.     

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.     

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.     

Determination of 7-Ketocholesterol and 7-Hydroxycholesterol in Meat Samples by TLC with Densitometric Detection

JPC – Journal of Planar Chromatography – Modern TLC - Concentrations of two oxycholesterols: 7-ketocholesterol and 7- hydroxycholesterol in meat samples (raw and cooked) were determined...     

Mononuclear to Polynuclear UIV Structural Units: Effects of Reaction Conditions on U-Furoate Phase Formation

Uranium(IV) complexation by 2-furoic acid (2-FA) was examined to better understand the effects of ligand identity and reaction conditions on species formation and stability. Five compounds were isolated: [UCl₂(2-FA)₂(H₂O)₂]_n ( 1 ), [U₄Cl₁₀O₂(THF)₆(2-FA)₂] ⋅ 2 THF ( 2 ), [U₆O₄(OH)₄(H₂O)₃(2-FA)₁₂] ⋅ 7 THF ⋅ H₂O ( 3 ), [U₆O₄(OH)₄(H₂O)₂(2-FA)₁₂] ⋅ 8.76 H₂O ( 4 ), and [U₃₈Cl₄₂O₅₄(OH)₂(H₂O)₂₀] ⋅ m H₂O ⋅ n THF ( 5 ). The structures were determined by single-crystal X-ray diffraction and further characterized by Raman, IR, and optical absorption spectroscopy. The thermal stability and magnetic behavior of the compounds were also examined. Variations in the synthetic conditions led to notable differences in the structural units observed in the solid state. At low H₂O/THF ratios, a tetranuclear oxo-bridged [U₄O₂] core was isolated. Aging of this solution resulted in the formation a U₃₈ oxo cluster capped by chloro and water ligands. However, at increasing water concentrations only hexanuclear units were observed. In all cases, at temperatures of 100–120 °C, UO₂ nanoparticles formed.     

The impact of structural biology on alkaloid biosynthesis research

Covering: 1997 to 2012In the recent past, macromolecular crystallography has gone through substantial methodological and technological development. The purpose of this review is to provide a general overview of structural biology and its impact on enzyme structure/function analysis and illustrate how it is modifying the focus of research relevant to alkaloid biosynthesis.     

Cascade Cyclizations of Terpenoid Polyalkenes Triggered by Photoelectron Transfer – Biomimetics with Photons

Light-induced cyclizations of suitably functionalized polyalkene terpenoids, such as geranyl, all-trans-farnesyl, and all-trans-geranylgeranyl derivatives, via formation of radical cations are proven to be a powerful method for the single-step synthesis of mono- and mostly all-trans-fused polycyclic compounds from readily available precursors. Whereas some of these highly stereo- and chemoselective transformations required the use of micel ar media, they can now be conveniently performed in homogeneous solutions upon suitable choice of the electron acceptors and of the functionality pattern of the polyalkene substrates. Moreover, the mode of cyclization, i.e., 6- vs. 5-membered ring formation and termination of the cyclization cascades, are steered efficiently by the substituents of the polyalkenes (polyalkenyl acetate vs. α,β-unsaturated ethyl polyalkenoate and polyalkene-1,1-dicarbonitrile). At the same time, the protic solvents used add highly stereoselectively to the ω-alkene sites of the polyalkens in anti-Markovnikov sense which strongly suggests that radical cations are intercepted. Interestingly, the transformations achieved here upon photoelectron transfer parallel the biosynthetic paths of non-oxidative terpene cyclizations which are thought to occur purely by protonation of the isoprenoid polyalkenes.     

Separation and analysis of nitroarenes from airborne particulate organic matter by HPLC and capillary GC-MS methods

Normal-phase HPLC has been applied to the separation of nitroarenes from dichloromethane extracts from airborne particulate matter samples collected in urban regions of Upper Silesia. GC-MS and capillary gas chromatography with NP detector analysis of the nitroarene fraction made it possible to identify and determine quantitatively those compounds which dominate in the organic matter emitted to the atmosphere in highly industrialized regions (2-nitrofluorene, isomeric nitroarenes of MW = 247, i.e. nitropyrene/nitrofluoranthene/nitroacephenanthrylene).