Effect of Some Macrocyclic Ligands on the Rate of Reduction of Perchlorate Ion by Titanium(III)

Complexation with cyclam increases the rate of reduction of perchlorate ion by TiIII (in acidic, aqueous, 4 mol dm-3 LiCl Solutions at 25 °C) relative to the rate of the corresponding reduction of Ti3+. A modified cyclam with pendant amine and p-aminobenzyl functional groups is more effective in this regard than is cyclam itself. Both redox reactions are acid catalyzed. The data is consistent with involvement of an intermediate containing two TiIII centers

Simulation of GEMASOLAR-based solar tower plants for the Chinese energy market: Influence of plant downsizing and location change.

In many countries that are experiencing a steep increase of energy demand, there is a growing challenge of responding to this demand by investing in renewable technologies for new power plants. Solar energy seems to be one of the best solutions to reduce the fossil fuels consumption for energy production purposes. In terms of high-power solar plants, concentrating towers are characterized by high efficiencies, but the investment costs are high as well. For this reason, a fundamental issue consists in simulating the solar tower behavior in different locations, in order to provide a precise estimation of both annual energy production and return of the investment. Among these types of solar plants, GEMASOLAR has been recently (2011) put in operation in Andalusia, Spain, and the data that have been obtained by this plant allow one to study its potential for application in different locations. The present work is aimed at simulating the GEMASOLAR plant behavior in some Chinese areas suitable for such a technology. All the simulations proposed here have been obtained through a Solar Advisor Model (SAM). Some of the simulations of the original plant have been modified forcing the plant to run without fossil fuel hybridization or changing its nominal power. After model validation, results have shown encouraging perspectives for the exploitation of this technology in China, with annual overall efficiencies of 14% for the 20 MW power plant (GEMASOLAR nominal power). In addition, the down-scaled plants have been optimized through native SAM software algorithm focusing on geometrical parameters. This procedure has been proved to be able of maintaining a high efficiency (14.97%) even for a 10 MW power plant. The focus has been on pilot plants, since they could represent the first step towards a deep exploitation of concentrating solar thermal power in China, with a relatively low capital risk

Folding propensity and biological activity of peptides: New insights from conformational properties of a novel peptide derived from Vitreoscilla haemoglobin

The synthetic peptide Vitr-p-13(YPIVGQELLGAIK-NH2), derived from the bacterial dimeric Vitreoscilla haemoglobin (VHb) in the position 95-107, is characterized by a preeminent "statistical coil" conformation in water as demonstrated by CD experiments and long time-scale MD simulations. In particular, Vitr-p-13 does not spontaneously adopt an alpha-helix folding in Water, but it is rather preferentially found in beta-hairpin-like conformations. Long time-scale MD simulations have also shown that Vitrp-13 displays a "topological-trigger" which initiates alpha-helix folding within residues 7-10, exactly like seen in the temporins, a group of linear, membrane-active antimicrobial peptides of similar length. At variance with temporins, in Vitr-p-13 such a process is energetically very demanding (+ 10 kJ/mol) in water at 300 K, and the peptide was found to be unable to bind model membranes in vitro and was devoid of antimicrobial activity. The present results,, compared with previous studies on similar systems, strengthen the hypothesis of the requirement Of a partial folding when still in aqueous environment to allow a peptide to interact with cell-membranes and eventually exert membrane perturbation-related antibiotic effects on target microbial cells

Folding propensity and biological activity of peptides: New insights from conformational properties of a novel peptide derived from Vitreoscilla haemoglobin.

The synthetic peptide Vitr-p-13 (YPIVGQELLGAIK-NH2), derived from the bacterial dimeric Vitreoscilla haemoglobin (VHb) in the position 95–107, is characterized by a preeminent ‘‘statistical coil’’ conformation in water as demonstrated by CD experiments and long time-scaleMD simulations. In particular, Vitr-p-13 does not spontaneously adopt an alpha-helix folding in water, but it is rather preferentially found in beta-hairpin-like conformations. Long time-scale MD simulations have also shown that Vitrp- 13 displays a ‘‘topological-trigger’’ which initiates alphahelix folding within residues 7–10, exactly like seen in the temporins, a group of linear, membrane-active antimicrobial peptides of similar length. At variance with temporins, in Vitr-p-13 such a process is energetically very demanding (110 kJ/mol) in water at 300 K, and the peptide was found to be unable to bind model membranes in vitro and was devoid of antimicrobial activity. The present results, compared with previous studies on similar systems, strengthen the hypothesis of the requirement of a partial folding when still in aqueous environment to allow a peptide to interact with cell-membranes and eventually exert membrane perturbation-related antibiotic effects on target microbial cells

Discovery of Novel Integrin Ligands from Combinatorial Libraries Using a Multiplex “Beads on a Bead” Approach

The development of screening approaches to identify novel affinity ligands has paved the way for a new generation of molecular targeted nanomedicines. Conventional methods typically bias the display of the target protein to ligands during the screening process. We have developed an unbiased multiplex “beads on a bead” strategy to isolate, characterize, and validate high affinity ligands from OBOC libraries. Novel non-RGD peptides that target α_vβ₃ integrin were discovered that do not affect cancer or endothelial cell biology. The peptides identified here represent novel integrin-targeted agents that can be used to develop targeted nanomedicines without the risk of increased tumor invasion and metastasis