Energy transfer from the second excited singlet state of spirobifluorene

Summary Energy transfer from the second excited state of spirobifluorene is examined by polarization spectroscopy. Evidence against spiroconjugation and evidence in favor of a coulombic mechanism is reviewed and discussed. This coulombic interaction is categorized as an intramolecular energy transfer caused by the extrinsic factors of the Weber nomenclature.     

Complexity and Context-Dependency

It is argued that given the “anti-anthropomorphic” principle—that the universe is not structured for our benefit—modelling trade-offs will necessarily mean that many of our models will be context-specific. It is argued that context-specificity is not the same as relativism. The “context heuristic”—that of dividing processing into rich, fuzzy context-recognition and crisp, conscious reasoning and learning—is outlined. The consequences of accepting the impact of this human heuristic in the light of the necessity of accepting context-specificity in our modelling of complex systems is examined. In particular the development of “islands” or related model clusters rather than over-arching laws and theories. It is suggested that by accepting and dealing with context (rather than ignoring it) we can push the boundaries of science a little further.     

A mutation in stratifin is responsible for the repeated epilation (Er) phenotype in mice

Stratifin (Sfn, also called 14-3-3sigma) is highly expressed in differentiating epidermis and mediates cell cycle arrest. Sfn is repressed in cancer, but its function during development is uncharacterized. We identified an insertion mutation in the gene Sfn in repeated epilation (Er) mutant mice by positional cloning. Er/+ mice expressed a truncated Sfn protein, which probably contributes to the defects in Er/Er and Er/+ epidermis and to cancer development in Er/+ mice.     

Mutation of TBCE causes hypoparathyroidism-retardation-dysmorphism and autosomal recessive Kenny-Caffey syndrome

The syndrome of congenital hypoparathyroidism, mental retardation, facial dysmorphism and extreme growth failure (HRD or Sanjad-Sakati syndrome; OMIM 241410) is an autosomal recessive disorder reported almost exclusively in Middle Eastern populations. A similar syndrome with the additional features of osteosclerosis and recurrent bacterial infections has been classified as autosomal recessive Kenny-Caffey syndrome (AR-KCS; OMIM 244460). Both traits have previously been mapped to chromosome 1q43-44 (refs 5,6) and, despite the observed clinical variability, share an ancestral haplotype, suggesting a common founder mutation. We describe refinement of the critical region to an interval of roughly 230 kb and identification of deletion and truncation mutations of TBCE in affected individuals. The gene TBCE encodes one of several chaperone proteins required for the proper folding of alpha-tubulin subunits and the formation of alpha-beta-tubulin heterodimers. Analysis of diseased fibroblasts and lymphoblastoid cells showed lower microtubule density at the microtubule-organizing center (MTOC) and perturbed microtubule polarity in diseased cells. Immunofluorescence and ultrastructural studies showed disturbances in subcellular organelles that require microtubules for membrane trafficking, such as the Golgi and late endosomal compartments. These findings demonstrate that HRD and AR-KCS are chaperone diseases caused by a genetic defect in the tubulin assembly pathway, and establish a potential connection between tubulin physiology and the development of the parathyroid.