Metal nanoparticles play an important role in many different areas such as catalysis, electronics, sensors, and cancer therapy. Silver, in its many oxidation states (Ag0, Ag+, Ag2+, and Ag3+), has long been recognized as having an inhibitory effect towards many bacterial strains and microorganisms commonly present in medical and industrial processes. Silver was introduced in various materials including hydroxyapatite due to its biocompatibility. The unique size-dependent properties of nanomaterials make them superior and indispensable.
In this work, nanohydroxyapatite/poly vinylpyrrolidone composite was doped with 2 different concentrations of silver nanoparticles prepared by reduction method. Several techniques like TEM, XRD, FT-IR, and SEM with EDS were used to characterize the prepared samples. The bioactivity test (soaking in SBF) at different short time intervals was characterized by using inductively coupled plasma-optical emission spectroscopy (ICP-OES) method. It is demonstrated that silver-doped nanohydroxyapatite obviously improves the bioactivity of the apatite at the early stages of immersion. The antibacterial inhibition over 3 types of bacteria (Staphylococcus aureus, Streptococcus mutans, and Pseudomonas) is under investigation.
The response of human bone marrow cell to bone ash-derived hydroxyapatite (HA) and tuna bone derived HA powders was compared. HA ceramics were prepared from the commercial bone ash and waste of tuna bone. HA powders were prepared by soaking the bone ash and tuna bone in 0.1M of NaOH solution at 80 Â°C for 4 hours. Both powders were calcined at 800 Â°C for 1 hour to completely remove organic and were attritor-milled for 24 hours. The bone ash-derived HA (AHA) and tuna bone-derived HA (THA) ceramics were prepared by cold isostatically pressed and sintered 1200 Â°C with a dwell time of 1 hour. A human bone cell line MG-63 cells were used to test biocompatibility of AHA and THA ceramics. Cell suspensions in DMEM containing 10% FBS and 1% penicillin-streptomycin were seeded onto 24-well plate containing THA and AHA ceramics. Cell proliferation was evaluated by MTS assay, and cell morphology was observed by SEM.
Highly strained 3C-SiC/Si (001) epilayers of different thicknesses (0.1 μm-12.4 μm) prepared in a vertical reactor configuration by chemical vapor deposition (V-CVD) method were examined using Raman scattering spectroscopy (RSS). In the near backscattering geometry, our RSS results for “as-grown” epilayers revealed TO- and LO-phonon bands shifting towards lower frequencies by approximately ~2 cm-1 with respect to the “free-standing” films.
Raman scattering data of optical phonons are carefully analyzed by using an elastic deformation theory with inputs of hydrostatic-stress coefficients from a realistic lattice dynamical approach that helped assess biaxial stress, in plane tensile- and normal compressive-strain, respectively. In each sample, the estimated value of strain is found at least two order of magnitude smaller than the one expected from lattice mismatch between the epilayer and substrate.
Porous ceramic biomaterials, namely, “artificial bone” are achieving some mainstream acceptance in the field of regenerative medicine on hard tissues. Recently, the numbers of artificial bones and their manufacturing process are found on papers and webs, and the situation implies as if we affirmed acceptable artificial bones. However, there seem to exist unsolved issues in the situation of artificial bone-based therapy.
Unsolved issues are establishing custom-made method and assurance of high connectivity and geometrical features of pores in ceramic artificial bones. Because they are highly production-dependent matters, innovative production process that guarantees the issues is required. To address the innovation, we developed an original method for porous ceramics fabrication named “Mosaic-like ceramics fabrication (MLCF)” that fabricates porous ceramics in brick-like manner.
Gum Arabic, exudates of several species of acacia, is typical of gum that contains Arabin. Gum Arabic of finest quality is obtained from Acacia Senegal and A. Arabica found in western and northern Africa. The Gum forms a clear thick solution in water. In this work, the foundry properties of Gum Arabic were investigated to ascertain its suitability as a composite binder for core production.
Various percentages of Gum Arabic and some conventional foundry binders were prepared and their binding properties determined. Since the binder has low limit hydration, it does not require the use of much water during mixture preparation. For the purpose of this work, 4%-6% of the Gum Arabic was used with conventional binders like bentonite, water glass, industrial starch, linseed oil to prepare core mixtures. A higher percentage (13-15%) of Gum Arabic alone was also used. Foundry properties like permeability, scatter index; mould ability index, moisture content, compressive strength tests and refractoriness were examined. The results revealed that the binder has a low refractoriness of 1200°C. This has the advantage of enhanced and good collapsibility during knock out.