Iminophosphanes and Diphosphenes - Recent Developments

Abstract

Novel iminophosphane derivatives are synthesized by nucleophilic displacement from Cl-P=NMes*. Structures, spectroscopic data, and novel chemical reactions of these compounds are discussed. Furthermore, synthesis of stable cis- and trans isomers of a diphos phene, as well as their mutual interconversion, is reported.     

Pulse electrodeposition and characterization of non-continuous,multi-element-doped hydroxyapatite bioceramic coatings

Journal of Solid State Electrochemistry - Multi-element-modified bioactive hydroxyapatite (mHAp) coatings were developed onto commercial titanium alloy material (Ti6Al4V) in clusters. The coatings...     

Bioactive glass (type 45S5) nanoparticles: in vitro reactivity on nanoscale and biocompatibility

Bioactive glasses represent important biomaterials being investigated for the repair and reconstruction of diseased bone tissues, as they exhibit outstanding bonding properties to human bone. In this study, bioactive glass (type 45S5) nanoparticles (nBG) with a mean particle size in the range of 20?C60?nm, synthesised by flame spray synthesis, are investigated in relation to in vitro bioreactivity in simulated body fluid (SBF) and response to osteoblast cells. The structure and kinetics of hydroxyapatite formation in SBF were investigated using transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR) revealing a very rapid transformation (after 1?day) of nBG to nanocrystalline bone-like carbonated HAp. Additionally, calcite is formed after 1?day of SBF immersion because of the high surface reactivity of the nBG particles. In the initial state, nBG particles were found to exhibit chain-like porous agglomerates of amorphous nature which are transformed on immersion in SBF into compact agglomerates covered by hydroxyapatite with a reduced size of the primary nanoparticles. In vitro studies revealed high cytocompatibility of nBG with human osteoblast cells, indicated through high lactatedehydrogenase (LDH) and mitochondrial activity as well as alkaline phosphatase activity. Hence, this study contributes to the understanding of the structure and bioactivity of bioactive glass (type 45S5) nanoparticles, providing insights to the phenomena occurring at the nanoscale after immersion in SBF. The results are relevant in relation to the understanding of the nanoparticles?? bioreactivity required for applications in bone tissue engineering.     

ULTRAVIOLET ENHANCED REACTIVATION OF HERPES SIMPLEX VIRUS INACTIVATED BY DIFFERENT WAVELENGTHS OF UV RADIATION

The degree of ultraviolet enhanced reactivation (UVR) exhibited by mammalian cells when infected with Herpes simplex virus inactivated by different wavelengths of far ultraviolet (UV) radiation was measured. A wavelength dependence for this effect is presented over the wavelength region 238–297 nm. Within the limits of the deviations obtained, the degree of UVR exhibited is similar at each wavelength. This suggests that virus irradiated with different wavelengths of UV radiation received the same type of damage or that cells repaired the different types of viral damage with the same efficiency.     

THE WAVELENGTH DEPENDENCE OF HERPES SIMPLEX VIRUS INACTIVATION BY ULTRAVIOLET RADIATION

The effect of different wavelengths of ultraviolet (UV) radiation on Herpes simplex virus when assayed on mammalian cells (measured by plaque forming ability) was investigated. The wavelength dependence of viral inactivation was obtained for 11 different wavelengths over the region 238–297 nm. The resulting action spectrum does not closely follow the absorption spectrum of either nucleic acid or protein. The most effective wavelengths for viral inactivation are over the region 260–280 nm.     

Development of 3D Biofabricated Cell Laden Hydrogel Vessels and a Low‐Cost Desktop Printed Perfusion Chamber for In Vitro Vessel Maturation

The vascular system represents the key supply chain for nutrients and oxygen inside the human body. Engineered solutions to produce sophisticated alternatives for autologous or artificial vascular implants to sustainably replace diseased vascular tissue still remain a key challenge in tissue engineering. In this paper, cell‐laden 3D bioplotted hydrogel vessel‐like constructs made from alginate di‐aldehyde (ADA) and gelatin (GEL) are presented. The aim is to increase the mechanical stability of fibroblast‐laden ADA‐GEL vessels, tailoring them for maturation under dynamic cell culture conditions. BaCl₂ is investigated as a crosslinker for the oxidized alginate‐gelatin system. Normal human dermal fibroblast (NHDF)‐laden vessel constructs are optimized successfully in terms of higher stiffness by increasing ADA concentration and using BaCl₂, with no toxic effects observed on NHDF. Contrarily, BaCl₂ crosslinking of ADA‐GEL accelerates cell attachment, viability, and growth from 7d to 24h compared to CaCl₂. Moreover, alignment of cells in the longitudinal direction of the hydrogel vessels when extruding the cell‐laden hydrogel crosslinked with Ba²⁺ is observed. It is possible to tune the stiffness of ADA‐GEL by utilizing Ba²⁺ as crosslinker. In addition, a customized, low‐cost 3D printed polycarbonate (PC) perfusion chamber for perfusion of vessel‐like constructs is introduced.