Initiation and Polymer Density of Conjugated Polymer Brushes

The growth mechanism and polymer density in conjugated polymer brush (CPB) films composed of poly(3-methylthiophene) (P3MT) are characterized. X-ray photoelectron spectroscopy experiments show that the initiation of aryl halide monolayers by Pd(PtBu3)2 produces disproportionated monolayer initiators. Unlike disproportionated species formed during the solution-phase initiation of aryl halides, which cannot mediate polymerization, the surface-bound initiators catalyze polymerization to form CPB films with a high grafting density (1.2 nm-2). Rutherford backscattering spectrometry (RBS) experiments show that P3MT CPB films have a characteristic monomer volume density (3.7 nm-3) that is indistinguishable from the volume density of spuncast poly(3-hexylthiophene) films. Using these RBS and XPS results, characteristics of P3MT CPB growth are obtained, including the turnover frequency (7.5 h-1) and polymer molecular weight (300 g/mol·nm)

Transcriptional regulator PRDM12 is essential for human pain perception.

Pain perception has evolved as a warning mechanism to alert organisms to tissue damage and dangerous environments. In humans, however, undesirable, excessive or chronic pain is a common and major societal burden for which available medical treatments are currently suboptimal. New therapeutic options have recently been derived from studies of individuals with congenital insensitivity to pain (CIP). Here we identified 10 different homozygous mutations in PRDM12 (encoding PRDI-BF1 and RIZ homology domain-containing protein 12) in subjects with CIP from 11 families. Prdm proteins are a family of epigenetic regulators that control neural specification and neurogenesis. We determined that Prdm12 is expressed in nociceptors and their progenitors and participates in the development of sensory neurons in Xenopus embryos. Moreover, CIP-associated mutants abrogate the histone-modifying potential associated with wild-type Prdm12. Prdm12 emerges as a key factor in the orchestration of sensory neurogenesis and may hold promise as a target for new pain therapeutics

Diurnal transcript profiling of the diatom Seminavis robusta

Coastal regions contribute an estimated 20% of annual gross primary production in the oceans, despite occupying only 0.03% of their surface area. Diatoms frequently dominate coastal sediments, where they experience large variations in light regime resulting from the interplay of diurnal and tidal cycles. Here, we report on an extensive diurnal transcript profiling experiment of the motile benthic diatom Seminavis robusta. Nearly 90% (23 328) of expressed protein-coding genes and 66.9% (1124) of expressed long intergenic non-coding RNAs showed significant expression oscillations and are predominantly phasing at night with a periodicity of 24 h. Phylostratigraphic analysis found that rhythmic genes are enriched in highly conserved genes, while diatom-specific genes are predominantly associated with midnight expression. Integration of genetic and physiological cell cycle markers with silica depletion data revealed potential new silica cell wall-associated gene families specific to diatoms. Additionally, we observed 1752 genes with a remarkable semidiurnal (12-h) periodicity, while the expansion of putative circadian transcription factors may reflect adaptations to cope with highly unpredictable external conditions. Taken together, our results provide new insights into the adaptations of diatoms to the benthic environment and serve as a valuable resource for the study of diurnal regulation in photosynthetic eukaryotes