Graph theoretical characterization and computer generation of certain carcinogenic benzenoid hydrocarbons and identification of bay regions

An algorithm is developed for generating and characterizing carcinogenic catacondensed benzenoid hydrocarbons. The bay regions in these structures are identified by a technique that we developed at Johns Hopkins. Using the three-digit code proposed by Balaban, and the concept of ring adjacency matrix expounded here, we generate catacondensed benzenoid hydrocarbons in the computer and identify the number of potentially carcinogenic bay regions in each of them. The results of computer generation agree with the combinatorial enumeration of Harary and Read. All structures containing up to five rings and some with six rings and the number of bay regions in these are presented. Computer results for the structures and bay regions of all seven-, eight-, and nine-membered unbranched catacondensed benzenoid hydrocarbons and the number of bays are available from the authors.     

Nanoscopic Imaging of meso‐Tetraalkylporphyrins Prepared in High Yields Enabled by Montmorrilonite K10 and 3 Å Molecular Sieves

We have developed a high‐yielding synthesis of meso‐tetraalkylporphyrins, which previously have been obtained only in lower yields. By employing Montmorrilonite K10 as the acid catalyst and 3 Å molecular sieves as the dehydrating agent, yields that reached 70 % could be achieved with some aliphatic aldehydes. The free‐base porphyrins with decyl ( C10 ) or longer chains were imaged at the single‐molecule level at the solvent/surface interface. Highly oriented pyrolytic graphite (HOPG) was used as a π‐stacking surface, whereas 1‐phenyloctane and 1‐phenylnonane were used as solvents. An odd–even effect was observed from C13 to C16 . For C13 a single‐crystal X‐ray structure allowed an unprecedented insight into how packing from two dimensions is expanded into a three‐dimensional crystal lattice.     

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].     

Catalytic acylation of amines with aldehydes or aldoximes

The simple nickel salt NiCl(2)·6H(2)O catalyzes the coupling of aldoximes with amines to give secondary or tertiary amide products. The aldoxime can be prepared in situ from the corresponding aldehyde. The use of (18)O-labeled oximes has allowed insight into the mechanism of this reaction.     

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.     

Strong valid inequalities for a class of concave submodular minimization problems under cardinality constraints

Mathematical Programming - We study the polyhedral convex hull structure of a mixed-integer set which arises in a class of cardinality-constrained concave submodular minimization problems. This...