Biaryl polyamides as a new class of DNA quadruplex-binding ligands

We report a novel class of biaryl polyamides highly selective for G-quadruplex DNA, and with significant cytotoxicity in several cancer cell lines; they form planar U-shaped structures that match the surface area dimensions of a terminal G-quartet in quadruplex structures rather than the grooves of duplex DNA.

Structure-based design of selective high-affinity telomeric quadruplex-binding ligands.

A library of triazole-based telomeric quadruplex-selective ligands has been developed that mimic an established family of tri-substituted acridine-based ligands, using crystal structure data as a starting-point for computer-based design. Binding affinities, estimated by electrospray mass spectrometry, are in accord with the design concept.

Tetra-end-linked oligonucleotides forming DNA G-quadruplexes: a new class of aptamers showing anti-HIV activity.

The biophysical and biological properties of unprecedented anti-HIV aptamers are presented. The most active aptamer (1L) shows a significant affinity to the HIV protein gp120.

Overcoming hydrolytic sensitivity and low solubility of phosphitylation reagents by combining ionic liquids with mechanochemistry

Ionic liquids have been used in combination with ball milling on a range of chlorophosphoramidite reagents to phosphitylate nucleosides and 2-deoxynucleosides. The enhanced stability offered by the ionic liquid mediated processes combined with efficient mass transfer induced by ball milling has enabled excellent yields to be obtained even when using small dialkyl amino groups as well as the more commonly used diisopropylamino protection.

A Frequency Domain Algorithm for Wave Separation

We propose a frequency domain adaptive algorithm for
wave separation in wind instruments. Forward and backward travelling waves are obtained from the signals acquired by two microphones placed along the tube, while the
separation ?lter is adapted from the information given by a
third microphone. Working in the frequency domain has a
series of advantages, among which are the ease of design of
the propagation ?lter and its differentiation with respect to
its parameters.
Although the adaptive algorithm was developed as a ?rst
step for the estimation of playing parameters in wind instruments it can also be used, without any modi?cations, for
other applications such as in-air direction of arrival (DOA)
estimation. Preliminary results on these applications will
also be presented.

Protein surface recognition using geometrically pure Ru(II) tris(bipyridine) derivatives

This manuscript illustrates that the geometric arrangement of protein-binding groups around a ruthenium(II) core leads to dramatic differences in cytochrome c (cyt c) binding highlighting that it is possible to define synthetic receptors with shape complementarity to protein surfaces.

Detection of DNA base variation and cytosine methylation at a single nucleotide site using a highly sensitive fluorescent probe

A fluorescent DNA probe containing an anthracene group attached via an anucleosidic linker can identify all four DNA bases at a single site as well as the epigenetic modification C/5-MeC via a hybridisation sensing assay.

Origin of Low CO2 Selectivity on Platinum in the Direct Ethanol Fuel Cell

Calculated answer: First-principles calculations have been applied to calculate the energy barrier for the key step in CO formation on a Pt surface (see picture; Pt blue, Pt atoms on step edge yellow) to understand the low CO2 selectivity in the direct ethanol fuel cell. The presence of surface oxidant species such as O (brown bar) and OH (red bar) led to an increase of the energy barrier and thus an inhibition of the key step. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Catalytic hydrogenation of tertiary amides at low temperatures and pressures using bimetallic Pt/Re-based catalysts

Hydrogenation of tertiary amides, in particular, N-methylpyrrolidin-2-one, can be efficiently facilitated by a TiO(2)-supported bimetallic Pt/Re catalyst at low temperatures and pressures. Characterisation of the catalysts and kinetic tests have shown that the close interaction between the Re and Pt is crucial to the high activity observed. DFT calculations were used to examine a range of metal combinations and show that the role of the uncoordinated Re is to activate the C=O and that of the Pt is as a hydrogenation catalyst, removing intermediates from the catalyst surface. The rate enhancement observed on the TiO(2) support is thought to be due to the presence of oxygen vacancies allowing adsorption and weakening of the C=O bond. (C) 2011 Elsevier Inc. All rights reserved.

Selective oxidation of a pyrimidine thioether using supported tantalum catalysts

Ta2O5-SiO2 catalysts were prepared by a sol-gel method using tetraethyl orthosilicate (TEOS) and tantalum (V) ethoxide as the sources of silicon and tantalum, and two families of quaternary ammonium salts, [CnH(2n+1)(CH3)(3)N]Br (n = 14, 16, 18) and [(CnH(2n+1))(4)N]Br (n = 10, 12, 16, 18) as surfactants. The catalysts were compared for the selective suffoxidation of 4,6-dimethyl-2-thiomethylpyrimidine using peroxide as an oxidising agent in a range of ionic liquids and organic solvents. The sol-gel catalysts were also compared with tantalum on MCM-41 prepared by grafting. The catalysts were characterized from adsorption-desorption isotherms of N-2, XRD patterns, small-angle X-ray scattering, IR spectra from adsorbed pyridine and CDCl3, XPS spectra, and Si-29 magic angle spinning (MAS) NNIR experiments. The effect of recycling on the catalyst leaching and selectivity/activity was also studied. High activities and selectivities were found in [NTf2](-) based ionic liquids and organic solvents with good recyclability of the catalyst. Tantalum was found in the solution after reaction; however, this was determined to be due to entrapment of catalyst particulates, as opposed to leaching of the active metal. (c) 2005 Elsevier Inc. All rights reserved.

Correction for a possible reversible adsorption over an "inert" material

All TAP micro-reactor configurations contain inert particles which are used so that the catalyst zone can be maintained under isothermal conditions. Even on

The use of short time-on-stream in situ spectroscopic transient kinetic isotope techniques to investigate the mechanism of hydrocarbon selective catalytic reduction (HC-SCR) of NOx at low temperatures

The problem of differentiating between active and spectator species that have similar infrared spectra has been addressed by developing short time-on-stream in situ spectroscopic transient isotope experimental techniques (STOS-SSITKA). The techniques have been used to investigate the reaction mechanism for the reduction of nitrogen oxides (NOx) by hydrocarbons under lean-burn (excess oxygen) conditions on a silver catalyst. Although a nitrate-type species tracks the formation of isotopically labeled dinitrogen, the results show that this is misleading because a nitrate-type species has the same response to an isotopic switch even under conditions where no dinitrogen is produced. In the case of cyanide and isocyanate species, the results show that it is possible to differentiate between slowly reacting spectator isocyanate species, probably adsorbed on the oxide support, and reactive isocyanate species, possibly on or close to the active silver phase. The reactive isocyanate species responds to an isotope switch at a rate that matches that of the rate of formation of the main product, dinitrogen. It is concluded that these reactive isocyanates could potentially be involved in the reduction of NOx whereas there is no evidence to support the involvement of nitrate-type species that are observable by infrared spectroscopy.

Evaluation of Pt and Re oxidation state in a pressurized reactor: difference in reduction between gas and liquid phase

Determination of metal oxidation state under relevant working conditions is crucial to understand catalytic behaviour. The reduction behaviour of Pt and Re was evaluated simultaneously as a function of support and solvent in a pressurized reactor (autoclave). The bimetallic catalysts are used in selective hydrogenation of carboxylic acids and amides. Gas phase reduction reduced the metals more efficiently, in particular Pt.

In situ study of ozone and hybrid plasma Ag-Al catalysts for the oxidation of toluene: Evidence of the nature of the active sites

Silver colloids have been prepared by reducing AgNO3 in aqueous solution and embeded in alumina following a sol-gel procedure in the presence of Pluronic 84 ((EO)(19)(PO)(39)(EO)(19)), as surfactant. Plasma-catalytic experiments aimed at the mineralization of toluene showed that the selectivity to CO2 was significantly increased in the presence of Ag catalysts compared with results obtained using the plasma alone. In-situ studies of the ozone interaction with catalysts provide an insight into the nature of the active sites of supported silver colloids for mineralization reactions. It is noticeable that when ozone is chemisorbed on embedded Ag colloidal catalysts no change in the silver oxidation state or size is found. The population of the chemisorbed species is higher at lower temperatures, where the non-selective decomposition of ozone is smaller. The catalysts exhibit high stability, preserving the structural and textural properties after the catalytic tests, that is indeed very important in the presence of ozone. (C) 2011 Elsevier B.V. All rights reserved.