Antibacterial mechanism with consequent cytotoxicity of different reinforcements in biodegradable magnesium and zinc alloys: A review

Benefits achieved by the biodegradable magnesium(Mg) and zinc(Zn) implants could be suppressed due to the invasion of infectious microbial, common bacteria, and fungi. Postoperative medications and the antibacterial properties of pure Mg and Zn are insufficient against biofilm and antibiotic-resistant bacteria, bringing osteomyelitis, necrosis, and even death. This study evaluates the antibacterial performance of biodegradable Mg and Zn alloys of different reinforcements, including silver(Ag), copper(Cu), lithium(Li), and gallium(Ga). Copper ions(Cu^(2+)) can eradicate biofilms and antibiotic-resistant bacteria by extracting electrons from the cellular structure. Silver ion(Ag^(+)) kills bacteria by creating bonds with the thiol group. Gallium ion(Ga^(3+)) inhibits ferric ion(Fe^(3+)) absorption, leading to nutrient deficiency and bacterial death. Nanoparticles and reactive oxygen species(ROS) can penetrate bacteria cell walls directly, develop bonds with receptors, and damage nucleotides. Antibacterial action depends on the alkali nature of metal ions and their degradation rate, which often causes cytotoxicity in living cells. Therefore, this review emphasizes the insight into degradation rate, antibacterial mechanism, and their consequent cytotoxicity and observes the correlation between antibacterial performance and oxidation number of metal ions.

Statistical Model for Impact and Energy Absorption of 3D Printed Coconut Wood-PLA

Fused deposition modeling(FDM)-3D printing has been the favored technology to build functional components in various industries.The present study investigates infill percentage and infill pattern effects on the printed parts’impact properties through the 3D printing technique using coconut wood-filled PLA composites.Mathematical models are also proposed in the present study with the aim for future property prediction.According to the ASTM standard,fifteen specimens with different parameter combinations were printed using a low-cost FDM 3D printer to evaluate their impact properties.Statistical analysis was performed using MINITAB to validate the experimental data and model development.The experimental outcomes reveal the honeycomb pattern with 75%infill density achieves the highest energy absorption(0.837 J)and impact energy(5.1894 kJ/m^(2)).The p-value from statistical analysis clearly shows that all the impact properties are less than the alpha value of 0.05,suggesting all the properties are vital to determine the impact properties.The validation process affirms that the generated mathematical model for the energy absorbed and the impact energy is reliable at an acceptable level to predict their respective properties.The errors between the experimental value and the predicted value are 3.98%for the energy absorbed and 4.06%for impact energy.The findings are expected to provide insights on the impact behavior of the coconut wood-filled PLA composites prepared by FDM-3D printing and a mathematical model to predict the impact properties.

Improved Thermophysical Properties of Developed Ternary Nitrate-Based Phase Change Material Incorporated with MXene as Novel Nanocomposites

In this study,nanocomposite of ternary nitrate molten salt induced with MXene is developed.LiNO3-NaNO3-KNO3 with wt%of 35:12:53 and 35:10:55 are produced and doped with MXene in the wt%of 0.2,0.5,1.0,and 1.5.FTIR result indicates the composites had no chemical reaction occurred during the preparation.UV-VIS analysis shows the absorption enhancement with respect to the concentration of MXene.Thermogravimetric analysis(TGA)was used to measure the thermal stability of the LiNO_(3)-NaNO_(3)-KNO_(3) induced with MXene.The ternary molten salts were stable at temperature range of 600–700°C.Thermal stability increases with the addition of MXene.1.5 wt%of MXene doped with LiNO_(3)-NaNO_(3)-KNO_(3) with wt%35:10:55 and 35:12:53,increases the thermal stability from 652.13°C to 731.49°C and from 679.82°C to 684.57°C,respectively.Using thermophysically enhanced molten salt will increase the efficiency of CSP.

An Updated Review on Low-Temperature Nanocomposites with a Special Focus on Thermal Management in Buildings

Buildings contribute to 33%of total global energy consumption,which corresponds to 38%of greenhouse gas emissions.Enhancing building’s energy efficiency remains predominant in mitigating global warming.Advance-ments in thermal energy storage(TES)techniques using phase change material(PCM)have gained much attention among researchers,primarily to minimize energy consumption and to promote the use of renewable energy sources.PCM technology stays as the most promising technology for developing high-performance and energy-efficient buildings.The major drawback of PCM is its poor thermal conductivity which limits its potential use which could be resolved by dispersing conductive nanofillers.The acquired database on synthesis routes,properties,and performance of nano-dispersed phase change materials(NDPCMs)with various techniques presented in the paper should deliver useful information in the production of NDPCMs with desirable characteristics mainly for building construction applications.An outline of contemporary developments and use of NDPCMs as TES medium is delivered.Finally,a brief discussion on challenges and the outlook was also made.In-depth research is needed to explore the fundamental mechanisms behind the enhanced thermal conductivity of NDPCM with nanofillers dispersion and also a thorough investigation on how these mechanisms drive improvement in building performance.