Structural Characteristics of a Family of Bioactive Glasses Formed by Replacing Varying Amounts of SiO 2 in 45S5 Glass with B 2O 3

2019 ◽  
Author(s):  
Xu Cui ◽  
Chengcheng Huang ◽  
Wenhai Huang ◽  
Deping Wang ◽  
Haobo Pan ◽  
...  
2007 ◽  
Vol 336-338 ◽  
pp. 1534-1537 ◽  
Author(s):  
Hua De Zheng ◽  
Ying Jun Wang ◽  
Chun Rong Yang ◽  
Xiao Feng Chen ◽  
Na Ru Zhao

The spherical nano-sized bioactive particles in the system of CaO-P2O5-SiO2 were bio-mimetically synthesized using micro-emulsion method. The microstructures and properties of the bio- mimetic nano-materials were characterized using XRD, FTIR, SEM/EDAX and TEM techniques. It was indicated that the nano-particles possessed glassy structural characteristics. The porous composite for bone tissue reconstruction was prepared by compounding poly (hydroxybutyrate-2-co-2-hydroxyvalerate) (PHBV) and the nano-particles of bio-mimetic bioactive glasses (BMBG). Bone-like hydroxyl- carbonate-apatite (HCA) could formed on the surface of porous composite by immersing the composite in simulated body fluid (SBF) at 37°C for 8 hours. With increase of immersion time, the morphology of HCA changed from spherical into flake-like crystals. The study on cells attachment of the porous PHBV/BMBG composite proved that the material possessed satisfactory bioactivity, bio-mineralization function and cells biocompatibility.


2015 ◽  
Vol 62 (2) ◽  
pp. 71-79
Author(s):  
Vukoman Jokanović ◽  
Božana Čolović ◽  
Dejan Marković ◽  
Slavoljub Živković

SUMMARY Bioactive glasses are often used nanomaterials in tissue engineering of bone and soft tissue. Many newly synthesized materials for applications in medicine and dentistry are based on these bioactive substances. Bioactive glass is usually used as a scaffold or as an implant coating on implants and it allows fast formation of apatite layer with positive effect on osteoblasts proliferation. These biomaterials play an important role in dentistry and endodontics. This study is mostly part of the monograph titled “Nanomedicine, the Greatest Challenge of the 21st Century”, that for two years has received attention from professional and scientific community in various fields. Information presented in this paper highlight structural characteristics of bioactive glasses that have a significant role in bone tissue engineering


Author(s):  
R. Gronsky

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.


Author(s):  
V. Annamalai ◽  
L.E. Murr

Economical recovery of copper metal from leach liquors has been carried out by the simple process of cementing copper onto a suitable substrate metal, such as scrap-iron, since the 16th century. The process has, however, a major drawback of consuming more iron than stoichiometrically needed by the reaction.Therefore, many research groups started looking into the process more closely. Though it is accepted that the structural characteristics of the resultant copper deposit cause changes in reaction rates for various experimental conditions, not many systems have been systematically investigated. This paper examines the deposit structures and the kinetic data, and explains the correlations between them.A simple cementation cell along with rotating discs of pure iron (99.9%) were employed in this study to obtain the kinetic results The resultant copper deposits were studied in a Hitachi Perkin-Elmer HHS-2R scanning electron microscope operated at 25kV in the secondary electron emission mode.


Author(s):  
G. M. Michal

Several TEM investigations have attempted to correlate the structural characteristics to the unusual shape memory effect in NiTi, the consensus being the essence of the memory effect is ostensible manifest in the structure of NiTi transforming martensitic- ally from a B2 ordered lattice to a low temperature monoclinic phase. Commensurate with the low symmetry of the martensite phase, many variants may form from the B2 lattice explaining the very complex transformed microstructure. The microstructure may also be complicated by the enhanced formation of oxide or hydride phases and precipitation of intermetallic compounds by electron beam exposure. Variants are typically found in selfaccommodation groups with members of a group internally twinned and the twins themselves are often observed to be internally twinned. Often the most salient feature of a group of variants is their close clustering around a given orientation. Analysis of such orientation relationships may be a key to determining the nature of the reaction path that gives the transformation its apparently perfect reversibility.


Author(s):  
Christopher Viney

Light microscopy is a convenient technique for characterizing molecular order in fluid liquid crystalline materials. Microstructures can usually be observed under the actual conditions that promote the formation of liquid crystalline phases, whether or not a solvent is required, and at temperatures that can range from the boiling point of nitrogen to 600°C. It is relatively easy to produce specimens that are sufficiently thin and flat, simply by confining a droplet between glass cover slides. Specimens do not need to be conducting, and they do not have to be maintained in a vacuum. Drybox or other controlled environmental conditions can be maintained in a sealed chamber equipped with transparent windows; some heating/ freezing stages can be used for this purpose. It is relatively easy to construct a modified stage so that the generation and relaxation of global molecular order can be observed while specimens are being sheared, simulating flow conditions that exist during processing. Also, light only rarely affects the chemical composition or molecular weight distribution of the sample. Because little or no processing is required after collecting the sample, one can be confident that biologically derived materials will reveal many of their in vivo structural characteristics, even though microscopy is performed in vitro.


1998 ◽  
Vol 17 (1) ◽  
pp. 531-539 ◽  
Author(s):  
Akiko Kondow ◽  
Shin-ichi Yokobori ◽  
Takuya Ueda ◽  
Kimitsuna Watanabe

INEOS OPEN ◽  
2020 ◽  
Vol 3 ◽  
Author(s):  
S. A. Sorokina ◽  
◽  
Yu. Yu. Stroilova ◽  
V. I. Muronets ◽  
Z. B. Shifrina ◽  
...  

Among the compounds able to efficiently inhibit the amyloid aggregation of proteins and decompose the amyloid aggregates that cause neurodegenerative diseases, of particular interest are dendrimers, which represent individual macromolecules with the hypercrosslinked architectures and given molecular parameters. This short review outlines the peculiarities of the antiamyloid activity of dendrimers and discusses the effect of dendrimer structures and external factors on their antiamyloid properties. The potential of application of dendrimers in further investigations on the aggregation processes of amyloid proteins as the compounds that exhibit the remarkable antiamyloid activity is evaluated.


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