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Several newly obtained titanium alloys were characterized in order to evaluate the biocompatibility and their possible application as implants. For improvement of the performances of the TiMo alloys compared to other alloys, silicon was added, targeting good mechanical and technological properties, avoiding the toxic effects for human body. Titanium is very used in medical applications, due to their extremely low toxicity and good chemical stability in different body fluids. Four Ti15Mo x Si (where x = 0, 0.5, 0.75, 1.0 wt %), alloys were developed and investigated regarding microstructure, mechanical, chemical and biological behavior (in vitro and in vivo evaluation). By increasing the Si content from 0 to 1% wt., the mechanical properties of the Ti15Mo alloys were significantly improved. By increasing the Si content from 0 to 1% wt., the mechanical properties of the Ti15Mo alloys were significantly improved (about 50%) from 44.50 GPa to 19.81 GPa modulus of elasticity and the hardness values 361.28 to 188.52 HV. The cytocompatibility assessment on human line osteoblasts indicated good cell-material interactions and in vivo tests indicated a successful osseointegration, the surrounding newly bone being formed without any significant inflammatory reaction. Expression of osteopontin in the peri-implant area highlights the presence of osteogenesis and bone mineralization. Metalloproteinase-2 (gelatinase A) and metallopeptidase-9 (gelatinase B) overexpression in osteoblasts, osteoclasts and osteocytes represent the markers of normal bone remodeling. All these results suggest that the TiMoSi alloys are promising materials for orthopedics devices, since mechanical properties and biocompatibility offer conditions for applying them as biomaterial. [ABSTRACT FROM AUTHOR]

Synthetic HAp becomes a major concern among researchers as it poses a risk of being expensive, complex, employing a time consuming method while also producing low biological activity HAp with lack of trace elements. Considering these issues, synthesizing HAp using natural resources had become a popular alternative way in order to obtain a high-performance HAp powder due to the presence of trace elements that improve the efficiency of HAp powder. However, only a few studies have focused on the synthesis of HAp by using natural sources in a simple and cost-effective manner to produce HAp with properties comparable to synthetic HAp. Thus, this review provides in depth analysis on the diverse methods that can be used to synthesize HAp from various natural resources. This would aid in finding the best method possible in synthesizing HAp with optimum properties to meet the requirements of tissue engineering applications. [ABSTRACT FROM AUTHOR]

The objective of the research is to obtain Ti20Mo x Si (where x = 0, 0.5, 0.75, 1.0 wt %) alloys using the vacuum arc remelting (VAR) methods and to consider the effects of Mo and Si on physical-chemical, biological and mechanical biocompatibility. Through microstructure analysis the dendrites, grains, sub-grains, compounds have been confirmed; Mo adding determined the main β phase apparition and by increasing the Si content the dendritic microstructure was evidenced. The modulus of elasticity decreases with the amount of Si in the Ti20Mo alloys. The MTT assessment and fluorescent microscopy performed on fibroblasts and osteoblasts cells indicated a suitable cytocompatibility of the prepared alloys. Expression of osteopontin, metalloproteinases 2 and 9 (MMP2 and MMP9) in these areas into the periosteum and peri-implant highlight the bone mineralization. Mineralization and bone remodeling suggest a good biocompatibility of the implanted material with human tissue. • Obtaining of new biocompatible Ti20Mo x Si alloys. • Addition of Si improves mechanical properties - low Young modulus and good hardness values. • Albino rabbit fibroblasts and human MG63 osteosarcoma cell line co-incubated with the material do not affect cell growth and morphology. • Expression of osteopontin, metalloproteinases 2 and 9 into the periosteum and peri-implant highlights the bone mineralization. [ABSTRACT FROM AUTHOR]

• Heat evolution is significant in understanding the alkali activation process. • Calorimetric data enables the interpretation of reaction kinetics of alkali activation. • Factors affecting alkali activation process which lead to variations of heat evolution. • Potential of heat evolution in understanding the ambient-curing/self-curing AAMs. • Potential of self-curing AAMs for on-site application as alternatives to the OPC. The usage of ordinary Portland cement (OPC) in construction has become a great concern among researchers due to the carbon dioxide (CO 2) emission during production. As alternatives, alkali-activated materials (AAMs), which include geopolymers, have been introduced as green material due to their similar properties to OPC and minimal CO 2 emission. This review highlights the heat evolution during alkali activation, which has been proven to be a reliable technique for providing information on the cumulative heat evolution and kinetic parameters, encompassing reaction rates, mechanism, and activation energy. The factors influencing heat evolution such as effect of materials used and parameters of mix design, including alkali solution concentration, alkali-activator ratios and solid-to-liquid ratios/liquid-to-solid ratios are briefly reviewed to highlight the significance of heat evolution in understanding the alkali activation process for the formation of AAMs. [ABSTRACT FROM AUTHOR]

• Mechanical and microstructure of solely GGBFS based geopolymers are investigated. • Solely binder of GGBFS based geopolymers obtained high strength after 28-day curing. • Synchrotron micro x-ray fluorescence reveals detailed distribution of tobermorite, calcite and dolomite in GGBFS samples. This paper investigates the strength development of solely ground granulated blast furnace slag geopolymers (GGBFS). An optimal combination of GGBFS with various solid/liquid and alkaline activator ratios had been determined by performing a number of compressive strength tests. It was found that GGBFS with 3.0 solid/liquid ratio and 2.5 alkaline activator ratio resulted in high compressive strength at 168.7 MPa after 28 days of curing. The microstructure analysis of the GGBFS geopolymers using SEM, FTIR and XRD revealed the formation of tobermorite and calcite (CaCO 3) phases within a three-dimensional system. In addition, an advanced characterisation non-destructive technique using the synchrotron micro-XRF was performed to reveal detail phase distribution in the system. It displayed that the calcium concentration was higher at silica and alumina regions, which described the formation of tobermorite and CaCO 3 as the contributing factor towards high compressive strength. [ABSTRACT FROM AUTHOR]