Chiral organocatalysts based on lipopeptide micelles for aldol reactions in water

A comprehensive study of the self-assembly in water of a lipopeptide consisting of a sequence of l-proline, l-arginine and l-tryptophan with a hydrocarbon chain has been performed. Fluorescence assays were used to determine the critical aggregation concentration. In situ small-angle X-ray scattering (SAXS) and molecular dynamics simulations showed the presence of spherical micelles with diameters around 6 nm. In agreement with these results, cryo-TEM images showed globular aggregates with diameters ranging from ≈4 nm up to ≈9 nm. Furthermore, the lipopeptide catalytic activity has been tested for the direct aldol reaction between cyclohexanone and p-nitrobenzaldehyde, and we have observed that the self-association of the organocatalyst played a critical role in the enhanced activity. Water affects the selectivity, and poor results are obtained under neat reaction conditions. The location of the catalytic groups at the lipopetide/water solvent interface also endowed unusual selectivity in the catalyzed aldol reactions. Under optimized reaction conditions, high yields (up to >99%), good enantioselectivity (ee up to 85%) and high diastereoselectivity (ds up to 92 : 8) were obtained.

Multifunctional biosensors based on peptide–polyelectrolyte conjugates

The crystal structure of self-assembled peptide nanostructures dictates the conductivity. We show that the orthorhombic phase can be doped with PAH, improving hole and electron injection, opening opportunities for self-assembled peptide composites.

Polycaprolactone fibers with self-assembled peptide micro/nanotubes: a practical route towards enhanced mechanical strength and drug delivery applications

The conjugation between micro/nanotubes of l,l-diphenylalanine and polycaprolactone has led to ductile composite fibers suitable for designing polymer membranes potentially usable as degradable skin patches in drug delivery.

Relaxation dynamics of deeply supercooled confined water in l,l-diphenylalanine micro/nanotubes

The temperature dependence (10–290 K) of the low-frequency (20–150 cm⁻¹) Raman-active phonon modes of deeply supercooled confined water in l,l-diphenylalanine micro/nanotubes was analyzed.

Mimics of copper proteins: structural and functional aspects

The importance of copper as an essential element can be estimated by the wide range of copper proteins and enzymes playing different roles in biological systems. In the last decades many bioinorganic studies were developed on mimetic complexes of copper-dependent proteins, in order to verify the interrelations between structural and functional properties of active copper centers. Among the most studied copper ion ligand, diimine compounds have deserved special attention due their flexibility, facility of preparation, and ability to stabilize both oxidation states of this metal. In our laboratory, we have been investigating some Schiff base copper complexes as mimics of different proteins, with emphasis on functional aspects, trying to elucidate mechanisms of reaction, based on proposed intermediary species, in addition to molecular shapes. Particularly, mimics of the copper-zinc superoxide dismutase, and of monooxigenases and oxidases exhibiting dicopper sites are discussed in this work.

Ethical considerations in neuroclinical trials

Ethical decision making in clinical trials has become increasingly emphasized at many levels of the review process. Ethical concepts applicable to Neuroclinical Trials (NCT) are reviewed. The discussion is directed towards ethical concerns that investigators must consider and justify prior to Institutional Review Board (IRB) submission. Risk-benefit analysis, methodology (randomization: placebo; design) and consent (informed; deferred; waived) are reviewed and Office for Protection from Research Risk (OPRR) guidelines are described. Our conclusions: Investigators proposing NCT face increasing ethical scrutiny by IRBs. Attention to ethical issues early in trial planning process is recommended.

Ethical considerations in clinical neuroscience. Current concepts in neuroclinical trials

BACKGROUND

Ethical decision making in clinical trials has become increasingly emphasized at many levels of the review process.

SUMMARY OF REVIEW

Ethical concepts applicable to neuroclinical trials are reviewed. The discussion is directed toward ethical concerns that investigators must consider and justify prior to institutional review board submission. Risk-benefit analysis, methodology (randomization, placebo, design), and consent (informed, deferred, waived) are reviewed and guidelines of the Office for Protection From Research Risk are described.

CONCLUSIONS

Investigators proposing neuroclinical trials face increasing ethical scrutiny by institutional review boards. Attention to ethical issues early in the trial planning process is recommended.