Characterization of Ceramic Filled Polymer Matrix Composite Used for Biomedical Applications

A particulate composite material was prepared by adding (CaCO3, CaO, MgCO3, MgO) ceramic particles with particle size of (2 (0.5% wt.). The results had revealed that the maximum values of tensile strength, compression, bending strength, hardness, impact energy and water absorption%, were (57.6828 N/mm2 at 3% wt. CaCO3, 124.0965 N/mm2 at 9% wt. CaCO3, 102.188 N/mm2 at 9% wt. MgO, 88.2 Shore D at 9% wt. CaCO3, 0.27 J at 6%wt. CaCO3 and 0.8432 % at 15%wt.CaO) compared with reference values, i.e.( 37.4742 N/mm2, 100.3563 N/mm2, 34.194 N/mm2, 83 Shore D, 0.36 J and 0.2626%) respectively.

Microstructure characterization and corrosion behavior of Mg-Y-Zn alloys with different long period stacking ordered structures

Mg-Y-Zn alloys with long period stacking ordered(LPSO)structure have received much attention recently and exhibit great potential in applications such as automotive,aerospace and in bio-medical fields.This paper aimed to investigate the effect of different phase constitution of LPSO structures on corrosion rate of bio-medical Mg-Y-Zn alloys.The results showed that as-cast Mg98.5Y1Zn0.5 alloys containing only 18R structure exhibited the highest corrosion resistance with the corrosion rate of 2.78 mm/year.The precipitation of 14H lamellas within a-Mg grains during solid solution treatment introduced the crystallographic orientation corrosion by accelerating micro-galvanic corrosion.The increase of 18R/14H interfaces deteriorated the corrosion resistance,and the grain boundaries also suffered from severe electrochemical dissolution.This work suggested that Mg-Y-Zn alloys with single LPSO structure(either 18R or 14H)exhibited better corrosion resistance than alloys with co-existence 18R and I4H LPSO structures.

State of arts on the bio-synthesis of noble metal nanoparticles and their biological application

Nanomaterials are materials in which at least one of the dimensions of the particles is 100 nm and below.There are many types of nanomaterials,but noble metal nanoparticles are of interest due to their uniquely large surface-to-volume ratio,high surface area,optical and electronic properties,high stability,easy synthesis,and tunable surface functionalization.More importantly,noble metal nanoparticles are known to have excellent compatibility with bio-materials,which is why they are widely used in biological applications.The synthesis method of noble metal nanoparticles conventionally involves the reduction of the noble metal salt precursor by toxic reaction agents such as NaBH4,hydrazine,and formaldehyde.This is a major drawback for researchers involved in biological application researches.Hence,the bio-synthesis of noble metal nanoparticles(NPs)by bio-materials via bio-reduction provides an alternative method to synthesize noble metal nanoparticles which are potentially non-toxic and safer for biological application.In this review,the bio-synthesis of noble metal nanoparticle including gold nanoparticle(AuNPs),silver nanoparticle(AgNPs),platinum nanoparticle(PtNPs),and palladium nanoparticle(PdNPs)are first discussed.This is followed by a discussion of these biosynthesized noble metal in biological applications including antimicrobial,wound healing,anticancer drug,and bioimaging.Based on these,it can be concluded that the study on bio-synthesized noble metal nanoparticles will expand further involving bio-reduction by unexplored bio-materials.However,many questions remain on the feasibility of bio-synthesized noble metal nanoparticles to replace existing methods on various biological applications.Nevertheless,the current development of the biological application by bio-synthesized noble metal NPs is still intensively ongoing,and will eventually reach the goal of full commercialization.

Effect of crystallographic texture and twinning on the corrosion behavior of Mg alloys:A review

Magnesium and its alloys have gained significant popularity due to their light weight and their potential for use as bioresorbable materials.However,their application is limited in practice due to their relatively poor corrosion resistance.Several methods are available for improving the corrosion resistance of Mg alloys for bio-applications such as using different coatings,alloying,and modifying the microstructural parameters such as the grain size and the crystallographic texture.This review provides a comprehensive summary of the effects of crystallographic texture and twinning,as one of the most important deformation mechanisms of Mg and Mg alloys,on the corrosion behavior.Regarding the crystallographic texture,it is shown that theoretically the basal planes should exhibit a lower corrosion rate but in some cases,such as when there is a galvanic effect or when corrosion films control the overall corrosion behavior,different results may take place.Also,there are contradictory results concerning the effect of twinning on the corrosion behavior.Thus,in some cases twinning may provide preferential sites for corrosion due to the higher energies of atoms located in the twin region by comparison with normal atomic positions in the crystalline lattice whereas there are also other examples where experiments show that twins produce more protective films than in the surrounding matrix.

Synthesis and Characterization of Hydroxyapatite Powder by Eggshell

Hydroxyapatite (HA) having chemical formula Ca10(PO4)6(OH)2, is the main chemical component of human bone tissue (70%). This is the reason why it has been widely engaged in the dental and non-load bearing implantations, to cope up with the bone response as a bioactive material. In this study HA powder was synthesized by wet chemical method, using phosphoric acid (H3PO4) and eggshells. The synthesized HA powder was characterized by X-ray diffraction analysis, Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX) and Fourier transform (FT-IR) spectroscopy. The Thermos gravimetric analysis (TGA-DTA) was also carried out to evaluate the stability of the synthesized HA powder at higher temperatures. The results of the study indicate that sintered (at 900°C) HA powder resembles the feature of pure and single apatite phase having favourable Ca/P ratio ranging from 1.7 to 2.4.

Experimental investigation of bioheat transfer characteristics induced by pulsed-laser irradiation

An experimental study of bioheat transfer characteristics induced bypulsed-laser irradiation was presented. The heat transfer characteristics of bio-materials, and theinfluences of pulse duration, power density, species of bio-materials, thickness and initialmoisture content of bio-materials on heat transfer were studied in details. The experimental resultsindicate that the penetration and absorption of laser in bio-materials are considerable, the heattransfer inside the bio-materials should include the effects of volumetric absorption, pulseduration, power density, bio-materials thickness, and material species have a significant influenceon the temperature variation.

Mechanical Simulation of a Diatom Frustule Structure

Diatoms possess intricately complicated nanopatterned silica outer shells, the so called frustules. Due to their excellent three-dimensional （3D） nanostructures, diatom frustules have attracted attentions from many fields to look for potential appli- cations, such as structural material design, light harvesting, photonics, molecular separation and bio-sensing. However, the mechanical property of frustule, especially the role of each single portion that structures a frustule, need to be clearly examined in order to provide a scientific support to frustule utilization. The reported work uses the Finite-Element （FE）-based simulation to investigate the relative mechanical properties of the frustule of the diatom Coscinodiscus sp. as compared with reference non-frustule structures. A three-dimensional model for the three featured layers of this frustule and a simplified model for its girdle band are built with the assistance of ABAQUS. A basic-cell concept is suggested; and the comparative results of several simulation groups are reported. The numerical results indicate that the seven-unit-cell model is able to catch the essential me- chanics of the Coscinodiscus sp. frustule under pressure and that the layered and porous structure of this frustule can effectively resist pressure.

Design,construction,and thermal performamce evaluation of an innovative bio-based ventilated facade

The energy consumption of the construction sector and its overall environmental impact has greater potential for improvement than those of many other sectors.Most energy consumed throughout the lifecycle of a building is expended during its operation and maintenance,for which the building envelope plays an important role.This study reports on the design,construction,and thermal performance evaluation of a ventilated facade.The facade should be quickly assembled,disassembled,and stored in containers for easy onward transport.Such features comply with the Rules and Buildins Code of the Solar Decathlon Middle East 2018 and the relevant Eurocodes.The facade is constructed using bio-based materials in keeping with the principles of a circular economy.The exterior cladding consists of sanitary paper,grass,reeds,recycled textiles,drinking water treatment waste,bio-based polyester resin,and other materials.Temperature and the air velocity measurements recorded on the facade in Dubai showed that the facade had contributed to cool temperatures within the apartment,particularly during the hottest hours of the day.The facade is a promising option for climates with hot summers and mild winters as it contributes to reducing energy consumption and the environmental impact of building materials.