Prospective clinical applications of nanosized drugs

Liposomes reduce toxicity of their encapsulated APIs. They allow drugs to penetrate cell membranes, serve as containers for drug delivery, protect drugs from enzymatic degradation, provide prolonged action due to slow drug release, and protect drugs from the reticuloendothelial system. Liposomeencapsulated drugs break through the blood brain barrier. Liposomes can solubilize water-insoluble drugs [54, 55, 58, 76, 77, 82].     

meso‐Ester Corroles

The introduction of ester groups on the 5‐ and 15‐meso positions of corroles stabilizes them against oxidation and induces a redshift of their absorption and emission spectra. These effects are studied through the photophysical and electrochemical characterization of up to 16 different 5,15‐diester corroles, in which the third meso position is free or occupied by an aryl group, a long alkyl chain, or an ester moiety. Single‐crystal X‐ray structure analysis of five 5,15‐diestercorroles and DFT and time‐dependent DFT calculations show that the strong electron‐withdrawing character of the 5,15 ester substituents is reinforced by their π overlap with the macrocyclic aromatic system. The crystal packing of corroles 2 , 4 , 6 , 9 , and 15 features short distances between chromophores that are stacked into columns thanks to the low steric hindrance of meso‐ester groups. This close packing is partially due to intermolecular interactions that involve inner hydrogen and nitrogen atoms, and thereby, stabilize a single, identical corrole tautomeric form.     

Effect of Hydrodynamic Forces on meso‐(4‐Sulfonatophenyl)‐Substituted Porphyrin J‐Aggregate Nanoparticles: Elasticity,Plasticity and Breaking

The J aggregates of 4‐sulfonatophenyl meso‐substituted porphyrins are non‐covalent polymers obtained by self‐assembly that form nanoparticles of different morphologies. In the case of high aspect‐ratio nanoparticles (bilayered ribbons and monolayered nanotubes), shear hydrodynamic forces may modify their shape and size, as observed by peak force microscopy, transmission electron microscopy of frozen solutions, small‐angle X‐ray scattering measurements in a disk‐plate rotational cell, and cone–plate rotational viscometry. These nanoparticles either show elastic or plastic behaviour: there is plasticity in the ribbons obtained upon nanotube collapse on solid/air interfaces and in viscous concentrated nanotube solutions, whereas elasticity occurs in the case of dilute nanotube solutions. Sonication and strong shear hydrodynamic forces lead to the breaking of the monolayered nanotubes into small particles, which then associate into large colloidal particles.     

The Temporal Ultraviolet Limit for Complex Bosonic Many-body Models

We consider the partition function for a many-body model consisting of a weakly coupled gas of bosons at any temperature T > 0 and any chemical potential μ, but with both infrared and ultraviolet cutoffs imposed in both temporal and spatial directions. We take the limit as the ultraviolet cutoff in the temporal direction is removed and develop a representation for the limit that, hopefully, provides a suitable starting point for controlling the limit as the infrared cutoffs are removed.     

meso-Tetrahydropyranylperoxides: molecular structures in solution,in the crystal,and by DFT calculations and their isomerization to the racemate

The crystalline peroxide 3a is the main product (out of 10 theoretically possible) from the aerial peroxidation of all-cis-2,4,6-trimethyltetrahydropyran (2a). It has a similar structure both in solution and in the crystal as shown by nuclear Overhauser effects and X-ray analysis, respectively. Theoretical calculations at a density functional theory level (B3LYP/6-31G) provide insight into the stabilities of the different stereoisomers of this peroxide, accounting for the facile, acid-catalyzed isomerization from the meso form to the racemate. Peroxide 3b, which is the 2-tert-butyl analogue of 3a, out of 22 theoretically possible isomers, crystallizes in a similar meso form. As a result of crystal packing effects and the intrinsically (axial) chiral peroxy "chromophore" that deviates slightly from the antiperiplanar conformation, both enantiomorphic forms of 3b are encountered in the lattice.     

Unique description of chemical structures based on hierarchically ordered extended connectivities (HOC procedures). I. Algorithms for finding graph orbits and canonical numbering of atoms

An iterative algorithm is described for finding topological equivalence, ordering, and canonical numbering of vertexes (atoms) in molecular graphs. Like the Morgan algorithm, it is based on extended connectivities but: (i) the latter are used hierarchically, i. e., the discrimination in the next iteration is carried out only for the vertices having the same extended connectivities (ranks) at the previous iteration; (ii) at equal extended connectivities, additional discrimination is introduced by the ranks of adjacent vertices; (iii) there is no “best name” search; (iv) three levels of complexity of chemical structures are distinguished and handled by different procedures. Two schemes of application of HOC procedures are presented: one directed towards a fast canonical numbering for coding systems, and another one yielding levels of topological equivalence allowing a unique topological representation of the molecule with possible applications to similarity search, structure-activity correlations, etc.