WO3 nano-spheres into W18O49 one-dimensional nano-structures through thermal annealing.

We elaborate the size controlled synthesis of nano-spheres and nano-crystals of WO3 by ultrasonic spray pyrolysis. The as-deposited particles are predominantly spherical in shape and tend to exhibit less agglomeration and a decrease in diameter as the process temperature is increased. Characterization was carried out using transmission (TEM) and scanning (SEM) electron microscopy, energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). One-dimensional nano-structures with the highest yield of WOx nano-wires were observed in a sample synthesized at 500 degrees C but only after thermal annealing of this sample at 500 degrees C for 17 hour in flowing argon. XRD revealed a high deficiency in oxygen in all samples suggesting that the nano-structures are transformed to sub-oxides of tungsten. Micro-diffraction patterns of a typical nano-wire reveal the monoclinic phase of W18O49.

Self Assembly and Properties of C:WO(3) Nano-Platelets and C:VO(2)/V(2)O(5) Triangular Capsules Produced by Laser Solution Photolysis.

Laser photolysis of WCl(6) in ethanol and a specific mixture of V(2)O(5) and VCl(3) in ethanol lead to carbon modified vanadium and tungsten oxides with interesting properties. The presence of graphene's aromatic rings (from the vibrational frequency of 1,600 cm(-1)) together with C-C bonding of carbon (from the Raman shift of 1,124 cm(-1)) present unique optical, vibrational, electronic and structural properties of the intended tungsten trioxide and vanadium dioxide materials. The morphology of these samples shows nano-platelets in WO(x) samples and, in VO(x) samples, encapsulated spherical quantum dots in conjunction with fullerenes of VO(x). Conductivity studies revealed that the VO(2)/V(2)O(5) nanostructures are more sensitive to Cl than to the presence of ethanol, whereas the C:WO(3) nano-platelets are more sensitive to ethanol than atomic C.

High-energy-resolution inelastic electron and proton scattering and the multiphonon nature of mixed-symmetry 2+ states in 94Mo.

High-energy-resolution inelastic electron scattering (at the S-DALINAC) and proton scattering (at iThemba LABS) experiments permit a thorough test of the nature of proposed one- and two-phonon symmetric and mixed-symmetric 2+ states of the nucleus 94Mo. The combined analysis reveals the one-phonon content of the mixed-symmetry state and its isovector character suggested by microscopic nuclear model calculations. The purity of two-phonon 2+ states is extracted.

Fine structure in the energy region of the isoscalar giant quadrupole resonance: characteristic scales from a wavelet analysis.

Fine structure in the energy region of the isoscalar giant quadrupole resonance in nuclei is observed in high-resolution proton scattering experiments at iThemba LABS over a wide mass range. A novel method based on wavelet transforms is introduced for the extraction of scales characterizing the fine structure. A comparison with microscopic model calculations including two-particle two-hole (2p2h) degrees of freedom identifies the coupling to surface vibrations as the main source of the observed scales. A generic pattern is also found for the stochastic coupling to the background of the more complex states.

Quantitative imaging microscopy for the sensitive detection of administered metal containing drugs in single cells and tissue slices--a demonstration using platinum based chemotherapeutic agent.

We described the use of Nuclear microscopy (microbeam PIXE) for the quantitative micron scale analysis of platinum based chemotherapeutic agents in individual cell and tissue slices. We demonstrate that microbeam PIXE has the sensitivity and accuracy to quantitatively measure the uptake of the chemotherapeutic agent cis-diamminedichloroplatinum (II) (cisplatin) and monitor other endogenous metal contents in single cells in a time- and dose-dependent fashion. Additionally, the technique can quantitatively image therapeutic levels of cisplatin and cisplatin analogs including cis-diammine[1,1-cyclobutanedicarboxylato] platinum (II) (carboplatin) in tissues from an animal model. This quantitative imaging microscopy has general application for the sensitive measurement of metal containing drugs/compounds at the cellular level and allows the study of cellular distribution and mechanism of action related to toxic response and cell function.

Formation of the epidermal calcium gradient coincides with key milestones of barrier ontogenesis in the rodent.

The epidermal permeability barrier forms late in gestation, coincident with decreased lipid synthesis, increased lipid processing, and development of a mature, multi-layered stratum corneum. Prior studies have shown that changes in the epidermal Ca++ gradient in vivo regulate lamellar body secretion and lipid synthesis, and modulations in extracellular Ca++ in vitro also regulate keratinocyte differentiation. We asked here whether a Ca++ gradient forms in fetal epidermis in utero, and whether its emergence correlates with key developmental milestones of barrier formation and stratum corneum development. Using either ion precipitation or proton induced X-ray emission analysis of fetal mouse and rat skin, we showed that a Ca++ gradient is not present at gestational days 16-18, prior to barrier formation, and that a gradient forms coincident with the emergence of barrier competence (day 19, mouse; day 20, rat) prior to birth. These results are consistent with a role for Ca++ in the regulation of key metabolic events leading to barrier formation. Whether the calcium gradient is formed actively or passively remains to be determined.