Endothelial progenitor cell secretome delivered by novel polymeric nanoparticles in ischemic hindlimb.

Endothelial progenitor cells (EPCs) contribute to ischemic tissue repair by paracrine secretion up-regulated by hypoxia. In this study we use novel nanoparticles (NPs) as carriers for a controlled release of EPC secretome (CM) to improve their angiogenic properties. The in vivo effect in ischemic hindlimb rat model was evaluated, comparing hypoxic EPC-CM-NPs with hypoxic EPC-CM alone.

QSPR Analysis of Copolymers by Recursive Neural Networks: Prediction of the Glass Transition Temperature of (Meth)acrylic Random Copolymers.

The glass transition temperature (Tg ) of acrylic and methacrylic random copolymers was investigated by means of Quantitative Structure-Property Relationship (QSPR) methodology based on Recursive Neural Networks (RNN). This method can directly take molecular structures as input, in the form of labelled trees, without needing predefined descriptors. It was applied to three data sets containing up to 615 polymers (340 homopolymers and 275 copolymers).

Size effects in nanoindentation of hard and soft surfaces.

Nanoindentation experiments carried out with atomic force microscopes (AFMs) open the way to understand size-related mechanical effects that are not present at the macro- or micro-scale. Several issues, currently the subject of a wide and open debate, must be carefully considered in order to measure quantities and retrieve trends genuinely associated with the material behaviour. The shape of the nanoindenter (the AFM tip) is crucial for a correct data analysis; we have recently developed a simple geometrical model to properly describe the tip effect in the nanoindentation process.

Evaluation of hierarchical structured representations for QSPR studies of small molecules and polymers by recursive neural networks.

This paper reports some recent results from the empirical evaluation of different types of structured molecular representations used in QSPR analysis through a recursive neural network (RNN) model, which allows for their direct use without the need for measuring or computing molecular descriptors. This RNN methodology has been applied to the prediction of the properties of small molecules and polymers. In particular, three different descriptions of cyclic moieties, namely group, template and cyclebreak have been proposed.

An atomic force microscopy tip model for investigating the mechanical properties of materials at the nanoscale.

Investigation of the mechanical properties of materials at the nanoscale is often performed by atomic force microscopy nanoindentation. However, substrates with large surface roughness and heterogeneity demand careful data analysis. This requirement is even more stringent when surface indentations with a typical depth of a few nanometers are produced to test material hardness.

AFM characterization of rabbit spermatozoa.

Atomic force microscopy (AFM) has been applied for determining the topological and structural features of rabbit spermatozoa. Fresh ejaculated spermatozoa were adsorbed passively onto a silicon slide or by motility from suspension onto a poly(L-lysine)-coated glass coverslip and then imaged in air and in buffer saline, respectively. AFM images clearly highlighted many details of spermatozoa head, neck, and tail.

Ionic peptide aggregation: exploration of conformational dynamics in aqueous solution by computational techniques.

The effects of end groups on KEK peptide conformational characteristics and self-assembling properties in water solution are investigated by using long lasting all-atom molecular dynamics simulations. The analysis of the structural macroscopic and microscopic properties and the examination of intra- and intermolecular interactions suggest, in agreement with experimental observations, the role played by side chains and terminal regions in determining the characteristic features of the assemblages. Competition between intra- and interchain interactions greatly affects the diffusivity of peptide molecules and the conformational space that they can sample, ultimately controlling the shape, size, and distribution of the aggregate configurations.

Bioerodible polymeric nanoparticles for targeted delivery of proteic drugs.

Significant efforts are being devoted to develop nanotechnology for drug delivery, mainly because of the distinct advantages offered by nanometer-size polymeric systems. Moreover, targeted drug delivery can be obtained by polymer conjugation to biospecific ligands. The present investigation was aimed mainly at determining the targeting ability of hybrid nanoparticles based on synthetic polymer/protein hybrid matrices.

New perspectives for (S)-dolichol and (S)- nor dolichol synthesis and biological functions.

A procedure is described for the preparation of (S)-dolichol and (S)- nor dolichol starting from the polyprenyl fraction extracted from Gingko biloba integer or exhausted leaves. The procedure appears extremely valuable in obtaining the two chiral isoprenoid compounds in good chemical yields and retention of a high degree of enantiomeric excess. Also, the (S)- nor dolichol represents a good chiral precursor for the preparation of (14)C-labelled (S)-dolichol to be used in biological investigations into the (S)-dolichol catabolism in the functional living cell.