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A poly(tert-butyl acrylate)-block-poly(2-cinnamoylethyl methacrylate), PtBA-b-PCEMA, sample was synthesized and characterized. After annealing at 105 ( 2 °C, the PtBA block formed densely packed cylinders inside the PCEMA matrix. Thin films of the diblock were obtained by microtomy. After PCEMA photo-cross-linking, the tert-butyl groups of PtBA were hydrolyzed, leaving poly(acrylic acid) chains in the loosely packed nanometer-sized cylinders. The permeability of water across such films varied by several orders of magnitude, depending on the pH of the aqueous medium or the types of cations in it. The possibility of using such nanochannels as templates for making further nanostructures was tested by filling the nanochannels with CdS or Fe 2 O 3 nanoparticles.

The solvatochromic comparison method has been used to probe the interactions of solutes with binary solvent mixtures of methanol-water and acetonitrile-water. The solute spectra recorded in these mixtures are composed of the additive spectral contributions of the different solvated species of the solute, i.e., the water-solvated species, the cosolvent-solvated species, and the species solvated by water-solvent complexes. Multivariate curve resolution-alternating least squares has been used to model the solvation of the solutes as a function of the composition of the binary solvent mixture. Spectra and concentration profiles of the dye surrounded by the different solvation environments have been isolated. For the first time, solute spectra solvated exclusively by methanol-water and acetonitrile-water complexes have been obtained, and the solvatochromic parameters of dipolarity/polarizability and hydrogen-bonding acidity have been estimated for these complex species.

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The solvatochromic method has been used to probe the solid/solution interface of bare silica and two modified silica surfacessphenyl bonded and C 18 bondedsin mobilephase mixtures of methanol-water and acetonitrilewater. Spectral measurements of solvatochromic dye solutions in different mobile-phase compositions and of slurries wetted by these same solutions have been recorded and used to characterize the different solid/ solution interfaces. Multivariate curve resolution has been employed to resolve the spectra collected into the contributions due to the different solvated species of the dye, i.e., those related to the dye associated with the stationary phase and those related to the dye solvated by the different species present in the mobile phase. Spectral profiles of the dyes solvated by a methanol-water complex in the presence of stationary phase have been resolved for the first time. Chromatographic capacity factors (k′) have been measured, and they have complementary information about how the retention of the dye changes with the mobile-phase composition on the different silica surfaces. The validity of the spectral studies performed to characterize real chromatographic environments, which are usually under much higher pressures, has been investigated. In a wide range going from atmospheric pressure to values higher than 100 bar, no significant variations of the capacity factors were observed for the dyes used, and therefore, the information about retention mechanisms and solid/solution interface properties obtained from the spectral studies can be safely extrapolated to the real chromatographic systems. The results obtained indicate that the phenyl bonded silica shows a dipolarity/ polarizability very similar to that of bare silica. For these two silica surfaces, the interactions of the dye and the stationary phase are independent of the mobile-phase composition. The C 18 bonded silica has a significantly lower polar character and evidences two retention mechanisms depending upon the mobile-phase composition.

Background: Spindle cell carcinoma (SpCC) is a rare microscopic type of cancer of the mouth and oropharynx. Although SpCC is thought to arise from squamous cell carcinoma (SCC), it carries a worse prognosis. Aim: To find out the difference in immunohistochemical expression of cytokeratin, vimentin and smoothmuscle actin, and mutational alterations in the K-ras oncogene between the two tumours, in an attempt to characterise SpCC. Methods: Immunohistochemical analysis was performed by standard avidin-biotin complex method in 35 cases each of SpCCs and SCCs. DNA extracted from paraffin wax-embedded tumours was used for PCR followed by single-strand conformation polymorphism for mutational analysis of K-ras exon 1 and exon 2. Results: In the SpCC group, cytokeratin positivity was significantly higher in epithelial areas (52.2%) than in spindle cell areas (16.1%), whereas vimentin was more positive in spindle cell areas (18.7%) than epithelial areas (2.7%). Cells intermediate between epithelial and spindle cell areas were consistently positive for both cytokeratin and vimentin. Cytokeratin was found to be significantly more positive in SCC (72.6%) than the squamous component and spindle cell component of SpCC. In this study, no mutation was detected in the Kras gene of either the SpCC or SCC group. Conclusions: The spindle cell component of SpCC is intermixed with cells that are morphologically mesenchymal but express dual antigen-positivity characteristic of epithelial (cytokeratin) and mesenchymal (vimentin) cells. These, possibly, are cells in transition suggesting that SpCC may be a sarcomatous metaplasia of SCC.

Ectomesenchymal chondromyxoid tumor (ECMT) is a rare tumor. Only 26 cases of ECMT have been reported, all occurred in the anterior tongue. We present a case of a 30-year-old male with a nodule in the hard palate, which was reported as ECMT on histopathology. The differential diagnosis considered included are extraskeletal myxoid chondroma, ECMT, pleomorphic adenoma, oral focal mucinosis, chondroid choristoma, and ossifying fibromyxoid tumor. After serial sections no other component was observed and a diagnosis of ECMT was made by exclusion. The patient is asymptomatic on follow up. A review of existing literature is also presented here.

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