Synthesis,Photophysics and Nonlinear Optical Properties of Stilbenoid Pyrimidine‐Based Dyes Bearing Methylenepyran Donor Groups

The nonlinear properties and the photophysical behavior of two π‐conjugated chromophores that incorporate an electron‐deficient pyrimidine core (A) and γ‐methylenepyrans as terminal donor (D) groups have been thoroughly investigated. Both dipolar and quadrupolar branching strategies are explored and rationalized on the basis of the Frenkel exciton model. Even though a cooperative effect is clearly observed if the dimensionality is increased, the nonlinear optical (NLO) response of this series is moderate if one considers the nature of the D/A couple and the size of the chromophores (as measured by the number of π electrons). This effect was attributed to a disruption in the electronic conjugation within the dyes’ scaffold for which the geometry deviates from planarity owing to a noticeable twisting of the pyranylidene end‐groups. This latter structural parameter also has a strong influence on the excited‐state dynamics, which leads to a very efficient fluorescence quenching.     

Improved In vitro and In vivo Cutaneous Delivery of Protoporphyrin IX from PLGA‐based Nanoparticles

We report the development of d , l lactic co‐glycolic acid) (PLGA)‐based nanoparticles (NPs) for topical delivery of protoporphyrin IX (PpIX), a photosensitizer (PS), in treatments like photodynamic therapy (PDT) of skin cancers. PpIX‐NPs were obtained in ~75.0% yield, encapsulation efficiency of 67.7%, drug content of 50.3 μg mg^?1, average diameter of 290 nm maintained up to 30 days and a zeta potential of 32.3 mV. Sustained in vitro release of PpIX through artificial membranes following Higuchi kinetics was kept up to 10 days. In vitro retentions of PpIX both in stratum corneum (SC) and epidermis + dermis ([EP + D]) were higher from NPs (23.0 and 10.0 times, respectively) compared to control solutions at all times. Quantification of PpIX by extraction, after in vivo skin application of NPs‐PpIX on hairless mice, showed higher retention of the PS both in SC and in [EP + D] (3.0 and 2.0 times, respectively) compared to control solutions. Taken together, the results indicate that NPs are suitable for PpIX encapsulation showing minimal permeation through the skin and a localized effect, characteristics of a potential and promising delivery system for PDT‐associated treatments of skin cancers, photodiagnosis and their off‐label uses.     

Generalized Γ Calculus and Application to Interacting Particles on a Graph

Potential Analysis - The classical Bakry-Émery calculus is extended to study, for degenerated (non-elliptic, non-reversible, or non-diffusive) Markov processes, questions such as...     

Pd–H and Ni–H phase diagrams using cluster variation method and Monte Carlo simulation

This work focuses on interstitial solid solutions of hydrogen in the face-centred cubic (fcc) host lattice of palladium and nickel, using a first-principles based approach. Cluster Variation Method (CVM) and Monte Carlo simulation algorithms were especially designed, allowing a coupled use of both techniques, to study hydrogen–vacancy interactions inside an fcc metallic host lattice. First-principles calculations provided the H–Vac interaction energies by structure inversion method. The phase diagrams and thermodynamic properties were computed using only theoretical inputs. The mechanisms leading to the formation of the miscibility gaps observed for both Pd–H and Ni–H systems and the hydrogen ordering on palladium interstitial lattice were reproduced without any empirical term.     

Externally definable sets and dependent pairs

We prove that externally definable sets in first order NIP theories have honest definitions, giving a new proof of Shelah’s expansion theorem. Also we discuss a weak notion of stable embeddedness true in this context. Those results are then used to prove a general theorem on dependent pairs, which in particular answers a question of Baldwin and Benedikt on naming an indiscernible sequence.     

Synthesis of (Z)-3-Deoxy-3-(1,2,3,6-Tetradeoxy-3,6-Imino-L-Arabino-Hexitol-1-C-Ylidene)-D-Xylo-Hexose Derivatives. First Examples Of Homo-(1→3)-C-Linked Iminodisaccharides.

ABSTRACT

Cross-aldolisation of 3,6-[(tert-butoxy)carbonyl]imino-2,3,6-trideoxy-4,5-O-isopropylidene-L-arabino-hexose (10) with 1,6-anhydro-2-O-benzyl-3-deoxy-β-D-erythro-hexopyrano-4-ulose (6) generates, after water elimination, a single enone 11 that is reduced selectively into an allylic alcohol 12, deprotection of which affords methyl (Z)-3-deoxy-3-(1,2,3,6-tetradeoxy-3,6-imino-L-arabino-hexitol-1-C-ylidene)-β-D-xylo-hexofuranoside (1) and (Z)-1,6-anhydro-3-deoxy-3-(1,2,3,6-tetradeoxy-3,6-imino-L-arabino-hexitol-1-C-ylidene)-β-D-xylo-hexopyranose (14).     

A New Synthesis of Methyl 3-Amino-3,4-dideoxy-β-D-xylo-hexopyranoside

Abstract

Benzylidenation of methyl β-D-glucopyranoside, followed by selective 3-O-tosylation, reductive acetal opening, chlorination, radical deoxygenation and transesterification, afforded methyl 2,3-anhydro-6-O-benzyl-4-deoxy-β-D-ribo-hexopyranoside 8. Subsequent epoxide opening with NaN₃ and catalytic hydrogenation led to the title compound.