Electrochemical investigation of covalently post-synthetic modified SURGEL coatings.

Thiol-yne click chemistry is used to covalently link a ferrocenyl derivative to the pore walls of a fully organic porous polymer coating (SURGEL). By cyclic voltammetry, it is demonstrated that the ferrocene bound to the SURGEL via a flexible alkyl linker can be reversibly reduced and oxidised. Surprisingly, when adding ferrocene as an electrolyte, a Nernstian diffusion limited process is observed. We explain this observation in terms of a high permeability of the SURGELs for ferrocene after the post synthetic modification.

Terahertz phase contrast imaging of sorption kinetics in porous coordination polymer nanocrystals using differential optical resonator.

The enhancement of light-matter coupling when light is confined to wavelength scale volumes is useful both for studying small sample volumes and increasing the overall sensing ability. At these length scales, nonradiative interactions are of key interest to which near-field optical techniques may reveal new phenomena facilitating next-generation material functionalities and applications. Efforts to develop novel chemical or biological sensors using metamaterials have yielded innovative ideas in the optical and terahertz frequency range whereby the spatially integrated response over a resonator structure is monitored via the re-radiated or leaked light. But although terahertz waves generally exhibit distinctive response in chemical molecules or biological tissue, there is little absorption for subwavelength size sample and therefore poor image contrast. Here, we introduce a method that spatially resolves the differential near-field phase response of the entire resonator as a spectral fingerprint. By simultaneously probing two metallic ring resonators, where one loaded with the sample of interest, the differential phase response is able to resolve the presence of guest molecules (e.g. methanol) as they are adsorbed or released within the pores of a prototypical porous coordination polymer.

Glucagon deficiency associated with hypoglycaemia and the absence of islet cell antibodies in the polyglandular failure syndrome before the onset of insulin-dependent diabetes mellitus: a case report.

The case of a female patient with fasting hypoglycaemia before the development of Type 1 (insulin-dependent) diabetes mellitus is reported. She presented with primary hypothyroidism, partial hypopituitarism, adrenal insufficiency and glucagon deficiency. Thyroid microsomal and gastric parietal cell antibodies were detected as well as HLA-B8, whereas islet cell antibodies were not demonstrable, even 2 years after the onset of diabetes. Plasma chromatography revealed true pancreatic glucagon (IRG3500) close to undetectable in basal samples with a questionable increase from 3 to 18 pg/ml during insulin-induced hypoglycaemia. After an overnight fast, moderate hyperaminoacidaemia was found with elevations of alanine, glycine, serine, arginine and ornithine as seen in pancreatectomized patients. It is suggested that the deficient glucagon secretion in this patient might, at least in part, have been the cause of fasting hypoglycaemia and the failure of glucose recovery following insulin-induced hypoglycaemia. Possible, the A cell deficiency was part of the polyglandular failure syndrome in this patient.