Bioactive polymeric materials for targeted administration of active agents: synthesis and evaluation

Bioerodible polymers displaying both stealth and targeting properties for the preparation of nanosystems for targeted and controlled delivery of fibrinolytic drugs to the thrombus were prepared by straightforward synthetic routes and characterized. Poly[(maleic anhydride)-alt-(butylvinyl ether)]s were synthesized in the presence of dodecyl mercaptan as chain transfer agent allowing for the preparation of copolymers with tunable molecular weight. 2-Methoxyethanol hemiesters containing antiopsonizing molecules of poly(ethylene glycol) were prepared and further biofunctionalized with a Fab fragment by a two-step reaction. In vitro biocompatibility investigation of the prepared materials supported their suitability for biomedical applications.     

General one-step synthesis of free hexofuranosyl 1-phosphates using unprotected 1-thioimidoyl hexofuranosides

A general one-step strategy is developed for the synthesis of hexofuranosyl 1-phosphates starting from new unprotected glycofuranosyl donors. It required first the preparation of new 1-thiohexofuranosides bearing a thioimidoyl heterocycle as a leaving group. The presence of sulfur and/or nitrogen atom(s) on the aglycon allowed remote activation of these thioglycofuranosides by anhydrous phosphoric acid and led to the target phosphates 9, 27, 29, and 30 in good to excellent selectivities and, more importantly, with very limited or no ring expansion. Moreover, this one-step phosphorylation reaction could be significantly improved by avoiding any tedious protecting group manipulations on negatively charged compounds and by focusing on a simple but general procedure of purification. This approach was applied to the diastereocontrolled synthesis of d-galacto- and d-glucofuranosyl 1-phosphates and also to the preparation of rare epimer and/or deoxy counterparts, that is, d-manno- and d-fucofuranosyl derivatives.     

Classical molecular dynamics model for coupled two component plasmas

This work is an improved continuation of a previous attempt to use classical molecular dynamics (MD) as a tool for the investigation of hot and dense “real” plasmas. “Real” in this context refers to ions and electrons interacting through Coulomb forces and undergoing ionization/recombination. The objective of designing such a non standard approach to plasma equilibrium is to explore a new way to discuss warm and dense matter with a method able to deal with the whole complexity of a N-body system of ions and electrons. Plasma relaxation times can be investigated up to a picosecond. The resulting equilibrium ion populations, built self consistently, are comparable to those found in literature and, potentially validate access to all the statistical data usually derived from MD simulations.     

Development of a flow-injection analysis (FIA) enzyme sensor for fructosyl amine monitoring

An enzyme-sensor system with flow-injection analysis (FIA) has been developed for the detection of fructosyl amine compounds; the sensor utilizes fructosyl amine oxidase isolated from the marine yeast Pichia sp. N1-1 strain. With this FIA system 0.2 to 10 mmol L(-1) fructosyl valine can be determined. The sensor is approximately five times more sensitive to fructosyl valine, a model compound for glycated hemoglobin HbA1c, than to N(epsilon)-fructosyl lysine, a model compound for glycated albumin. This FIA system can also be used to detect fructosyl dipeptides. The operational stability of the sensor enabled more than 120 consecutive sample injections over a period of approximately 20 h.     

Betti numbers in multidimensional persistent homology are stable functions

Multidimensional persistence mostly studies topological features of shapes by analyzing the lower level sets of vector‐valued functions, called filtering functions. As is well known, in the case of scalar‐valued filtering functions, persistent homology groups can be studied through their persistent Betti numbers, that is, the dimensions of the images of the homomorphisms induced by the inclusions of lower level sets into each other. Whenever such inclusions exist for lower level sets of vector‐valued filtering functions, we can consider the multidimensional analog of persistent Betti numbers. Varying the lower level sets, we obtain that persistent Betti numbers can be seen as functions taking pairs of vectors to the set of non‐negative integers. In this paper, we prove stability of multidimensional persistent Betti numbers. More precisely, we prove that small changes of the vector‐valued filtering functions imply only small changes of persistent Betti numbers functions. This result can be obtained by assuming the filtering functions to be just continuous. Multidimensional stability opens the way to a stable shape comparison methodology based on multidimensional persistence. In order to obtain our stability theorem, some other new results are proved for continuous filtering functions. They concern the finiteness of persistent Betti numbers for vector‐valued filtering functions and the representation via persistence diagrams of persistent Betti numbers, as well as their stability, in the case of scalar‐valued filtering functions. Finally, from the stability of multidimensional persistent Betti numbers, we obtain a lower bound for the natural pseudo‐distance. Copyright © 2013 John Wiley & Sons, Ltd.     

Self-dual sets of type (m, n) in projective spaces

In this paper we introduce and analyze the notion of self-dual k-sets of type (m, n). We show that in a non-square order projective space such sets exist only if the dimension is odd. We prove that, in a projective space of odd dimension and order q, self-dual k-sets of type (m, n), with , are of elliptic and hyperbolic type, respectively. As a corollary we obtain a new characterization of the non-singular elliptic and hyperbolic quadrics.     

Ionization Potential Depression in Hot Dense Plasmas Through a Pure Classical Model

The ionization potential of an ion embedded in a plasma, lowered due to the whole of the charged particles (ions and electrons) interacting with this ion, is the so‐called plasma effect. A numerical plasma model based on classical molecular dynamics has been developed recently. It is capable to describe a neutral plasma at equilibrium involving ions of various charge states of the same atom together with electrons. This code is used here to investigate the ionization potential depression (IPD). The study of the IPD is illustrated and discussed for aluminum plasmas at mid and solid density and electron temperatures varying from 50eV to 190eV. The method relies on a sampling of the total potential energy of the electron located at an ion being ionized. The potential energy of such electron results from all of the interacting charged particles interacting with it. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Rheology of carbon nanofiber-reinforced polypropylene

The rheological properties of two different nanocomposite systems consisting in the dispersion of carbon nanofibers (CNFs) in polypropylene are investigated. The nanoreinforced systems were identically prepared with two CNFs that differ only in the length of the fibers being otherwise identical to analyze the effect of fiber aspect ratio. Linear dynamic viscoelasticity and the steady-state rheology of the two different nanocomposites are presented. The system reinforced with CNFs with larger aspect ratio shows several rheological features that resemble peculiarities of rodlike polymers in the nematic liquid crystalline phase.     

Impact of glycosylation on physico–chemical and biological properties of nitrification inhibitors

The lipophilic 2-mercaptobenzothiazole (MBT), known for its nitrification inhibition properties, was derivatized thanks to direct glycosylation reactions. Similar transformations were also performed starting from 2-mercaptobenzimidazole (MBI), structurally close to MBT. The resulting S-linked mono- or disaccharides derived from d-glucose or l-arabinose, and cellobiose, gentiobiose or lactose, respectively, were subsequently studied as novel nitrification inhibitors without any further formulation or physical processes, except dilution in water. Along with ecotoxicity measurements, inhibition properties of the synthesized water soluble glycoconjugates were studied in a model reactor containing nitrification bacteria. The best results were obtained for the gentiobiosyl derivatives simply dissolved in water.