Nuclear Uptake of Gold Nanoparticles Deduced Using Dual‐Angle X‐Ray Fluorescence Mapping

Studies into the cell nucleus' incorporation of gold nanoparticles (AuNPs) are often limited by ambiguities arising from conventional imaging techniques. Indeed, it is suggested that to date there is no unambiguous imaging evidence for such uptake in whole cells, particularly at the single nanoparticle level. This shortcoming in understanding exists despite the nucleus being the most important subcellular compartment in eukaryotes and gold being the most commonly used metal nanoparticle in medical applications. Here, dual‐angle X‐ray flouresence is used to show individually resolved nanoparticles within the cell nucleus, finding them to be well separated and 79% of the intranuclear population to be monodispersed. These findings have important implications for nanomedicine, illustrated here through a specific exemplar of the predicted enhancement of radiation effects arising from the observed AuNPs, finding intranuclear dose enhancements spanning nearly five orders of magnitude.     

Planar Functions and Planes of Lenz-Barlotti Class II

Planar functions were introduced by Dembowski and Ostrom [4] to describe projective planes possessing a collineation group with particular properties. Several classes of planar functions over a finite field are described, including a class whose associated affine planes are not translation planes or dual translation planes. This resolves in the negative a question posed in [4]. These planar functions define at least one such affine plane of order 3^e for every e 4 and their projective closures are of Lenz-Barlotti type II. All previously known planes of type II are obtained by derivation or lifting. At least when e is odd, the planes described here cannot be obtained in this manner.     

Normal,abnormal and pseudo-abnormal reaction pathways for the imine-peroxyacid reaction

Steric and mesomeric effects have a marked influence upon the formation of oxaziridine (normal pathway) or nitrone (abnormal pathway) products from the imine-peroxyacid reaction; n.m.r. studies of the thermal isomerization of oxaziridines to nitrones provide evidence of a pseudo-abnormal oxidation pathway.     

Closure planes

We introduce a simple algebraic method for constructing infinite affine (and projective) planes from an infinite set of finite planes of prime power order stemming from a “root” plane. The construction uses finite fields and infinite extensions of finite fields in a critical way. We obtain a classical-looking result which states that if the construction succeeds over the algebraic closure of a finite field, then both the infinite plane and the original root plane must be Desarguesian. The Lenz–Barlotti types for these planes are then linked to the Lenz–Barlotti type of the root plane. Examples are then given. These show that under suitable conditions, the method can yield infinitely many non-isomorphic infinite planes. These examples are of Lenz–Barlotti types II.1 and V.1.     

Pharmaceutical Formulation and Characterization of Dipeptide Nanotubes for Drug Delivery Applications

Peptide nanotubes are promising materials for a variety of biomedical applications with ultrashort (≤7 amino acids) forms providing particular promise for clinical translation. The manufacture of peptide nanotubes has, however, been associated with toxic organic solvents restricting clinical use. The purpose of this work is to formulate dipeptide nanotubes using mild techniques easily translated to industrial upscale and to characterize their physiochemical and biological properties. Phenylalanine‐phenylalanine variants can be successfully formulated using distilled water as demonstrated here. Formulations are homogenous in shape (tubular), with apparent size (50–260 nm) and a zeta potential of up to +30 mV. L‐(H₂N‐FF‐COOH), and D‐enantiomers (H₂N‐ff‐COOH) demonstrate no toxicity against glioblastoma cells and are explored for ability to deliver a model hydrophilic molecule, sodium fluorescein, at pH 5.5 (tumor) and 7.4 (physiological). Peptide nanotubes loaded with >85% sodium fluorescein, demonstrate burst release characteristics, fitting the Weibull model of drug release. This research provides important data contributing to the pharmaceutical formulation of peptide nanotubes as drug delivery platforms for hydrophilic drugs.     

Parent homopolymers of liquid crystalline polyesters

A method that combines multi-temperature powder X-ray diffraction and molecular modelling is used to determine the high temperature crystal structures for poly-(p-phenylene terephthalate) (PPT) and poly-(p-hydroxybenzoic acid) (PHBA). Both have high temperature structures characterized by a degree of rotational disorder. In the case of PHBA there is a distinct high temperature phase above a well defined transition at 350°C, whereas the rotational disorder in ‘as polymerized’ PPT increases gradually between 370 and 475°C. The interchain packing at high temperatures still maintains phenyl edge to phenyl face correlations and, to some degree, carbonyl carbon to carbonyl oxygen contacts. The findings are relevant to the molecular structure and phase behaviour of liquid-crystalline polyesters as a class.