High resolution ultrastructure imaging of fractures in human dental tissues

Human dental hard tissues are dentine, cementum, and enamel. These are hydrated mineralised composite tissues with a hierarchical structure and versatile thermo-mechanical properties. The hierarchical structure of dentine and enamel was imaged by transmission electron microscopy (TEM) of samples prepared by focused ion beam (FIB) milling. High resolution TEM was carried out in the vicinity of a crack tip in dentine. An intricate “random weave” pattern of hydroxyapatile crystallites was observed and this provided a possible explanation for toughening of the mineralized dentine tissue at the nano-scale. The results reported here provide the basis for improved understanding of the relationship between the multi-scale nature and the mechanical properties of hierarchically structured biomaterials, and will also be useful for the development of better prosthetic and dental restorative materials.     

Synthesis of Ferromagnetic Nanoparticles in Detergent Solution

The synthesis conditions of ferromagnetic nanoparticles in anion detergent, cationic detergent, amphoteric detergent, and nonferrous detergent have been investigated in this study. The influencing factors, including kind of detergent, concentration of sodium hydroxide, and ratio of Fe²⁺ to Fe³⁺, are tested in detail. The factors affecting particle shape, size, and distribution have been reported. The characterization of ferromagnetic nanoparticles was detected using transmission electron microscope, X‐ray, UV‐spectra, and other method.     

A Study on Activity of SOD in CTAB Reverse Microeinulsion

The pyrogallic method for determining the activity of SOD is studied in the aqueous solution and in the CTAB/n-pentanol/n-octane/water microemulsion. The required generation ran of the substrate O₂ is obtained in he reverse microemulsion by increasing the apparent pH and dielectric constant. The activity of SOD is finally determined in such a system and a bell-shaped profile is recorded. But subactivity is found only due to the decrease of the substrate concentration and the high pH value     

Design and synthesis of trifunctional perfluorophenyl azide-based photoactivatable reagents

The novel trifunctional perfluorophenyl azide based photoactive compounds 3, 6 (unstable), 10 and 13 are described. Diels-Alder reaction of maleimide 13 with diene-heteropolytungstate 14 produced the PFPA-HPT-maleimide trifunctional conjugate 15.     

A description of hydrogen bonds in the chromium(III)-crosslinked collagen: insight from the molecular dynamics simulation

Structural Chemistry - The paper investigated the conformation and stability of the chromium(III)-crosslinked collagen fibers under different moisture contents by the molecular dynamics method,...