Synthesis and Biological Evaluation of New N-Acyl-α-amino Ketones and 1,3-Oxazoles Derivatives

In order to develop novel bioactive substances with potent activities, some new valine-derived compounds incorporating a 4-(phenylsulfonyl)phenyl fragment, namely, acyclic precursors from N-acyl-α-amino acids and N-acyl-α-amino ketones classes, and heterocycles from the large family of 1,3-oxazole-based compounds, were synthesized. The structures of the new compounds were established using elemental analysis and spectral (UV-Vis, FT-IR, MS, NMR) data, and their purity was checked by reversed-phase HPLC. The newly synthesized compounds were evaluated for their antimicrobial and antibiofilm activities, for toxicity on D. magna, and by in silico studies regarding their potential mechanism of action and toxicity. The 2-aza-3-isopropyl-1-[4-(phenylsulfonyl)phenyl]-1,4-butanedione 4b bearing a p-tolyl group in 4-position exhibited the best antibacterial activity against the planktonic growth of both Gram-positive and Gram-negative strains, while the N-acyl-α-amino acid 2 and 1,3-oxazol-5(4H)-one 3 inhibited the Enterococcus faecium biofilms. Despite not all newly synthesized compounds showing significant biological activity, the general scaffold allows several future optimizations for obtaining better novel antimicrobial agents by the introduction of various substituents on the phenyl moiety at position 5 of the 1,3-oxazole nucleus.     

Monitoring the synthesis of new polymer nanocomposites based on different polyhedral oligomeric silsesquioxanes using Raman spectroscopy

The kinetic behavior of the urethane dimethacrylate (UDMA) copolymerized and reinforced by different concentrations of polyhedral oligomeric silsesquioxane (POSS) with methacrylic groups was studied through Raman spectroscopy. UDMA‐POSS networks have been synthesized with three different types of POSS, two monofunctional POSS (1‐propylmethacrylate)‐heptaisobutyl substituted (HISO‐POSS) and heptacyclopentyl‐octasiloxan‐1‐yloxy) dimethylsilyl] propyl methacrylate (CPENTYL‐POSS) and one octafunctional POSS‐methacryl substituted (MA‐POSS). In order to show the influence of POSS on the final conversion, the hybrid systems were cured using three types of initiators which decompose at different temperatures: azobisisobutyronitrile (AIBN) (65 °C), benzoyl peroxide (BP) (80 °C) and di‐tert‐butyl peroxide (DTBP) (120 °C). The structure of the hybrid's surface was investigated by X‐ray photoelectron spectroscopy (XPS) and the T_g values were calculated from dynamic mechanical analysis (DMA) tests. Copyright © 2009 John Wiley & Sons, Ltd.     

Thermal decomposition of some biologically active complexes of ruthenium (III) with quinolone derivatives

A series of new complexes with mixed ligands of the type RuL₂(DMSO) _m Cl₃·nH₂O ((1) L: norfloxacin (nf), m = 1, n = 1; (2) L: ciprofloxacin (cp), m = 2, n = 2; (3) L: ofloxacin (of), m = 1, n = 1; (4) L: enrofloxacin (enro), m = 0.5, n = 4; DMSO: dimethylsulfoxide) were synthesised and characterised by chemical analysis and IR data. In all complexes both fluoroquinolone derivative and DMSO act as unidentate. The thermal behaviour steps were investigated in synthetic air flow. The thermal transformations are complex processes according to TG and DTG curves including dehydration, quinolone derivative and DMSO degradation respectively. The final product of decomposition is ruthenium (IV) oxide.     

Nanostructure dependence of field-effect mobility in regioregular poly(3-hexylthiophene) thin film field effect transistors

Low polydispersity regioregular polythiophenes with number average molecular weights ranging from 2 to 13 kDa were cast under the same conditions from solution to form a series of field effect transistors (FETs). Tapping mode AFM and grazing incidence small-angle X-ray scattering revealed that in all cases the polymers formed regular nanofibrillar morphologies with the width of nanofibrils proportional to the weight average contour length of polymer chains, indicating that conjugated backbones were oriented perpendicular to the nanofibril axes. FET charge carrier mobilities exhibited exponential dependence on nanofibril width, pointing to the decisive role of extended conjugated pathways in charge transport.     

Polysilanes. A New Route Toward High Performance EL Devices

The discovery of a remarkable class of plastics that can conduct electricity has opened a new era of plastics science and technology that has just been recognized by the award of the 2000 Nobel prize for chemistry. They can be used to make a wide range of electronic devices such as transistors, light-emitting diodes, solar cells and even lasers, through much simpler manufacture than conventional inorganic materials, increasing flexibility, reducing cost, and opening up new markets. Polysilanes are subject of an intensive research work aiming to various optoelectronic applications. Through this work the chemical structure of polydiphenylsilane was modified to obtain both solubility in common solvents and to induce new properties by attaching of various organic segments.     

Blood oxygenation monitoring using hyperspectral imaging after flap surgery

In this paper, we present a new method for the assessment of skin flap perfusion based on the non-invasive monitoring of skin blood oxygenation using hyperspectral imaging. This method consists of generation of oxyhemoglobin and deoxyhemoglobin maps in skin flap from hyperspectral image using an analytic model based on Beer–Lambert law. The results obtained on a fasciocutaneous sural flap have revealed that the oxyhemoglobin and deoxyhemoglobin maps facilitate the visualization of some differences between different areas of the flap, an aspect that clinical examination fails to do. In conclusion, the proposed method could provide a new option for a more accurate assessment of flap survival.     

Almost Global Existence for the Prandtl Boundary Layer Equations

We consider the Prandtl boundary layer equations on the half plane, with initial datum that lies in a weighted H¹ space with respect to the normal variable, and is real-analytic with respect to the tangential variable. The boundary trace of the horizontal Euler flow is taken to be a constant. We prove that if the Prandtl datum lies within \({\varepsilon}\) of a stable profile, then the unique solution of the Cauchy problem can be extended at least up to time \({T_{\varepsilon} \geqq {\rm exp}(\varepsilon^{-1} / {\rm log}(\varepsilon^{-1}))}\).     

Spectroscopic evaluation of painted layer structural changes induced by gamma radiation in experimental models

The degradation of cultural heritage objects by insects and microorganisms is an important issue for conservators, art specialists and humankind in general. Gamma irradiation is an efficient method of polychrome wooden artifacts disinfestation. Color changes and other modifications in the physical chemical properties of materials induced by gamma irradiation are feared by cultural heritage responsible committees and they have to be evaluated objectively and precisely. In this paper FTIR and FT-Raman spectroscopy methods were used to investigate the structural changes in some experimental models of tempera paint layers on wood following 11 kGy gamma irradiation at two dose rates. Radiation chemistry depends on the particular pigment, matrix formed by protein, resin (in case of varnished samples) and water presence. For the majority of painted layer in experimental models very small spectral variations were observed. Small changes in the FTIR spectra were observed for the raw sienna experimental model: for the higher dose rate the egg yolk protein oxidation peaks and the CH stretching bands due to lipids degradation products increased.