Oxide templates for self-assembling arrays of metal nanoclusters

We demonstrate that ordered arrays of metal clusters of a few nanometers in size can be fabricated by self-assembly on a range of oxide nanotemplates. Two systems were chosen, FeO/Pt(1 1 1) and Fe₃O₄, having in common a reconstructed close-packed oxygen surface layer. Deposition of various metal films results in the formation of nanosized clusters arranged according to the surface long-range order. Employing ab-initio calculations we discuss the observed mechanism of site-selective nucleation of the metal nanoclusters. Finally, we discuss the existence of a wide family oxide templates that can be used for self-assembled growth of nanoclusters governed by the same rules.     

Approaches for introducing high molecular diversity in scaffolds: Fast parallel synthesis of highly substituted 1H-quinolin-4-one libraries

We have developed a two steps strategy for the parallel synthesis of highly diversified quinolin-ones. In the first step we have combined and improved different synthetic methods for generating quinolin-4-ones bearing four different substitutions at specific positions using round bottomed flasks. The synthesis was assessed for a large number of substituted quinolin-4-ones. In the second step, the improved method was adapted to a parallel array synthesis using a 12 positions carrousel as demonstrated for the synthesis of 42-variable quinolin-4-ones. The first combinatorial library set 14(a-x) was obtained with a chemical purity of more than 95% without purification, the second library set 15(a-r), which included two synthetic steps, needed combinatorial purification using an innovative parallel purifier. The proposed approach contributes to a more extensive diversification of molecular scaffolds in general and provides access to highly substituted quinolinones in particular.     

Carbohydrate-based combinatorial libraries

Carbohydrate-based combinatorial libraries are tremendously valuable for studying the role of sugars in biology and for expanding accessible molecular diversity needed in broad-based drug screening programs. This review discusses the issues that are relevant to the successful implementation of comprehensive carbohydrate-based combinatorial library programs. In addition, details of oligosaccharide and glycoconjugate libraries constructed using both solid phase and solution phase strategies are presented. This revised version was published online in August 2006 with corrections to the Cover Date.     

Fano interference between the E2 (17 cm−1) optical mode and one-phonon continuum scattering from β-AgI

Resonant interference between the E₂ (17 cm^?1) optical mode and the continuum of one-phonon partial density of states has been observed in β-AgI, and has been shown to follow Fano formalism. The temperature dependence of the coupling parameter q shows a substantial variation as T approaches T_c. A qualitative explanation of such behaviour is made in terms of phonon assisted activation of Frenkel defects, which increases more rapidly as the superionic transition temperature is approached.     

Portuguese Propolis Antitumoral Activity in Melanoma Involves ROS Production and Induction of Apoptosis

Melanoma is the most aggressive and life-threatening skin cancer type. The melanoma genome is the most frequently mutated, with the BRAF mutation present in 40–60% of melanoma cases. BRAF-mutated melanomas are characterized by a higher aggressiveness and progression. Adjuvant targeted treatments, such as BRAF and MEK inhibitors, are added to surgical excision in BRAF-mutated metastatic melanomas to maximize treatment effectiveness. However, resistance remains the major therapeutic problem. Interest in natural products, like propolis, for therapeutic applications, has increased in the last years. Propolis healing proprieties offer great potential for the development of novel cancer drugs. As the activity of Portuguese propolis has never been studied in melanoma, we evaluated the antitumoral activity of propolis from Gerês (G18.EE) and its fractions (n-hexane, ethyl acetate (EtOAc), and n-butanol) in A375 and WM9 melanoma cell lines. Results from DPPH•/ABTS• radical scavenging assays indicated that the samples had relevant antioxidant activity, however, this was not confirmed in the cell models. G18.EE and its fractions decreased cell viability (SRB assay) and promoted ROS production (DHE/Mitotracker probes by flow cytometry), leading to activation of apoptotic signaling (expression of apoptosis markers). Our results suggest that the n-BuOH fraction has the potential to be explored in the pharmacological therapy of melanoma.     

Discovery of a Chiral DNA-Targeted Platinum–Acridine Agent with Potent Enantioselective Anticancer Activity

A structure–activity relationship study was performed for a set of rigidified platinum–acridine anticancer agents containing linkers derived from chiral pyrrolidine and piperidine scaffolds. Screening a library of microscale reactions and selected resynthesized compounds in non-small-cell lung cancer (NSCLC) cells showed that cytotoxicities varied by more than three orders of magnitude. A potent hit compound was discovered containing a (R)-N-(piperidin-3-yl) linker ( P2-6R ), which killed NCI-H460 and A549 lung cancer cells 100 times more effectively than the S enantiomer ( P2-6S ). P2-6R accumulated in A549 cells significantly faster and produced 50-fold higher DNA adduct levels than P2-6S . Ligand similarity analysis suggests that only module 6R may be compatible with strainless monofunctional intercalative binding. NCI-60 screening and COMPARE analysis highlights the spectrum of activity and potential utility of P2-6R for treating NSCLC and other solid tumors.     

Unraveling the Effect of the Hydration Level on the Molecular Mobility of Nanolayered Polymeric Systems

This work investigates the influence of the hydration level on the molecular mobility and glass transition dynamics of freestanding chitosan/alginate (CHT/ALG) nanolayered systems. Nonconventional dynamic mechanical analysis identifies two relaxation processes assigned to the α‐relaxation of the two biopolymers, respectively, CHT and ALG, when immersed in water/ethanol mixtures. This phenomenon explains the shape memory properties of the multilayered systems induced by hydration, thus constituting promising smart materials that would be of paramount importance in a plethora of research fields, including in the biomedical and biotechnological fields.     

Raman spectroscopy for identification and quantification analysis of essential oil varieties: a multivariate approach applied to lavender and lavandin essential oils

Lavender (Lavandula angustifolia) is used for cosmetics, perfumes and medicine (antimicrobial activity and relaxant properties) while lavandin (sterile hybrid of L. angustifolia P. Mill. × Lavandula latifolia (L.f.) Medikus) is used for air fresheners, deodorants and soaps. These plants are widely cultivated for essential oil production. In this study, 104 samples were analyzed including 62 lavandin and 42 lavender oil samples from several varieties. The Raman spectra are similar but can be differentiated by chemometrics treatment. Data structure may be studied by PCA. A PLS regression model was used for quantitative analysis of the main compounds such as linalyl acetate, linalool and eucalyptol. The reference data were obtained by gas chromatography. The performance of the method was also tested to discriminate between the two species and the seven varieties (Abrial, Fine, Grosso, Maillette, Matherone, Sumian and Super) by PLS‐DA regression. The examination of PLS and PLS‐DA regression coefficients allowed for the identification of species and of the varieties' metabolomic markers. Copyright © 2015 John Wiley & Sons, Ltd.