CF3-Containing para-Quinone Methides for Organic Synthesis.

A new family of CF3-containing para-quinone methides (CF3-QMs) was systematically investigated for its suitability in organic synthesis. Addition of different nucleophiles gives access to target molecules with a benzylic CF3-containing stereogenic center straightforwardly. The electrophilicity parameter E of the prototypical CF3-QM 2,6-di-tert-butyl-4-(2,2,2-trifluoroethylidene)cyclohexa-2,5-dien-1-one was determined to be -11.68 according to the Mayr scale, making it one of the most reactive quinone methides known so far.

Multimodal correlative investigation of the interplaying micro-architecture, chemical composition and mechanical properties of human cortical bone tissue reveals predominant role of fibrillar organization in determining microelastic tissue properties.

UNLABELLED: The mechanical competence of bone is crucially determined by its material composition and structural design. To investigate the interaction of the complex hierarchical architecture, the chemical composition and the resulting elastic properties of healthy femoral bone at the level of single bone lamellae and entire structural units, we combined polarized Raman spectroscopy (PRS), scanning acoustic microscopy (SAM) and synchrotron X-ray phase contrast nano tomography (SR-nanoCT). In line with earlier studies, mutual correlation analysis strongly suggested that the characteristic elastic modulations of bone lamellae within single units are the result of the twisting fibrillar orientation, rather than compositional variations, modulations of the mineral particle maturity, or mass density deviations. Furthermore, we show that predominant fibril orientations in entire tissue units can be rapidly assessed from Raman parameter maps. Coexisting twisted and oscillating fibril patterns were observed in all investigated tissue domains. Ultimately, our findings demonstrate in particular the potential of combined PRS and SAM measurements in providing multi-scalar analysis of correlated fundamental tissue properties. In future studies, the presented approach can be applied for non-destructive investigation of small pathologic samples from bone biopsies and a broad range of biological materials and tissues. STATEMENT OF SIGNIFICANCE: Bone is a complex structured composite material consisting of collagen fibrils and mineral particles. Various studies have shown that not only composition, maturation, and packing of its components, but also their structural arrangement determine the mechanical performance of the tissue. However, prominent methodologies are usually not able to concurrently describe these factors on the micron scale and complementary tissue characterization remains challenging. In this study we combine X-ray nanoCT, polarized Raman imaging and scanning acoustic microscopy and propose a protocol for fast and easy assessment of predominant fibril orientations in bone. Based on our site-matched analysis of cortical bone, we conclude that the elastic modulations of bone lamellae are mainly determined by the fibril arrangement.

Histochemical evidence of ß-chitin in parapodial glandular organs and tubes of Spiophanes (Annelida, Sedentaria: Spionidae), and first studies on selected Annelida.

A generic character of the genus Spiophanes (Annelida, Sedentaria: Spionidae) is the presence of parapodial glandular organs. Parapodial glandular organs in Spiophanes species include secretory cells with cup-shaped microvilli, similar to those present in deep-sea inhabiting vestimentiferans and frenulate Siboglinidae. These cells are supposed to secrete ß-chitin for tube-building. In this study, transverse histological and/or ultrathin sections of parapodial glandular organs and tubes of Spiophanes spp. as well as of Glandulospio orestes (Spionidae) and Owenia fusiformis (Oweniidae) were examined. Fluorescent markers together with confocal laser scanning microscopy, and Raman spectroscopy were used to detect chitin in the parapodial glandular organs of Spiophanes and/or in the glands of Owenia and Glandulospio. Tubes of these taxa were tested for chitin to elucidate the use of it for tube-building. The examinations revealed a distinct labelling of the gland contents. Raman spectroscopy documented the presence of ß-chitin in both gland types of Spiophanes. The tubes of Spiophanes were found to have a grid-like structure that seems to be built with this ß-chitin. Tests of tubes of Dipolydora quadrilobata (Spionidae) for chitin were negative. However, the results of our study provide strong evidence that Spiophanes species, O. fusiformis and probably also G. orestes produce chitin and supposedly use it for tube-building. This implies that the production of chitin and its use as a constituent part of tube-building is more widespread among polychaetes as yet known. The histochemical data presented in this study support previous assumptions inferring homology of parapodial glandular organs of Spionidae and Siboglinidae based on ultrastructure. Furthermore, transmission electron microscopy-based evidence of secretory cells with nail-headed microvilli in O. fusiformis suggests homology of parapodial grandular organs across annelids including Sipuncula.