On nonlinear gauge theories

In this note, we study non-linear gauge theories for principal bundles, where the structure group is replaced by a Lie groupoid. We follow the approach of Moerdijk–Mr?un and establish its relation with the existing physics literature. In particular, we derive a new formula for the gauge transformation which closely resembles and generalizes the classical formulas found in Yang Mills gauge theories.     

Toward the Rational Design of Galactosylated Glycoclusters That Target Pseudomonas aeruginosa Lectin A (LecA): Influence of Linker Arms That Lead to Low‐Nanomolar Multivalent Ligands

Anti‐infectious strategies against pathogen infections can be achieved through antiadhesive strategies by using multivalent ligands of bacterial virulence factors. LecA and LecB are lectins of Pseudomonas aeruginosa implicated in biofilm formation. A series of 27 LecA‐targeting glycoclusters have been synthesized. Nine aromatic galactose aglycons were investigated with three different linker arms that connect the central mannopyranoside core. A low‐nanomolar (K_d=19 nm , microarray) ligand with a tyrosine‐based linker arm could be identified in a structure–activity relationship study. Molecular modeling of the glycoclusters bound to the lectin tetramer was also used to rationalize the binding properties observed.     

The Boltzmann equation in classical Yang–Mills theory

We give a detailed derivation of the Boltzmann equation, and in particular its collision integral, in classical field theory. We first carry this out in a scalar theory with both cubic and quartic interactions and subsequently in a Yang–Mills theory. Our method does not rely on a doubling of the fields, rather it is based on a diagrammatic approach representing the classical solution to the problem.     

The di-iron subsite of all-iron hydrogenase: mechanism of cyanation of a synthetic [2Fe3S]-carbonyl assembly

This paper describes the kinetics and intimate mechanisms associated with cyanation of [2Fe3S] assemblies to give species structurally related to the subsite of all-iron hydrogenase. Stopped-flow FTIR spectroscopy has enabled the quantitation of the dynamics of five well-defined steps that experimentally illustrate the role of bridging carbonyls in the assembly of the dicyanide species, how on-off sulfur ligation can have a dramatic effect on cyanation kinetics and how the [2Fe3S] core stabilises bridging carbonyl species.     

Transient FTIR spectroelectrochemical and stopped-flow detection of a mixed valence (Fe(I)-Fe(II)) bridging carbonyl intermediate with structural elements and spectroscopic characteristics of the di-iron sub-site of all-iron hydrogenase

Iron(I) in biology?: one-electron oxidation of an (Fe(I)-Fe(I)) carbonyl cyanide precursor bearing a proximal thioether group leads to an (Fe(I)-Fe(II)) bridging carbonyl transient with spectral features similar to the di-iron sub-site of the CO inhibited paramagnetic centre of all-iron hydrogenase.     

Über die Erzeugung der 2. harmonischen Frequenz der Strahlung eines Nd-Lasers in KDP

Ohne Zusammenfassung     

Messung von Intensitätskorrelationsfunktionen bei Laserlicht

Ohne Zusammenfassung     

Aqueous enantioselective organocatalytic Diels-Alder reactions employing hydrazide catalysts. A new scaffold for organic acceleration

[reaction: see text] Cyclic hydrazides function as asymmetric organocatalysts in aqueous Diels-Alder reactions. The hydrazide is employed as the catalytic machinery in a compact camphor-derived framework that imparts facial selectivity to the cycloadditions. Kinetic evidence suggests the reaction involves rapid iminium formation.