Self-healing Coatings Loaded by Nano/microcapsules: A Review

Protection of Metals and Physical Chemistry of Surfaces - Coatings are applied on metallic surfaces to provide a dense barrier against the corrosive environment. However, coatings in most cases are...     

DGEBA-polyaminoamide as effective anti-corrosive material for 15CDV6 steel in NaCl medium: Computational and experimental studies

The present study is focusing on evaluating theoretically and experimentally stability and type of interactions between the epoxy resin bisphenol A diglycidyl ether (DGEBA)-polyaminoamide anticorrosive coating and high strength low alloy steel surface 15CDV6. The coated steel samples were subjected to a harsh environment of an electrolyte solution of 3 wt % NaCl to simulate the corrosive marine environment. The performance of the epoxy coating was investigated using electrochemical impedance spectroscopy (EIS). The EIS results revealed the occurrence of some deterioration in the film after subjecting it to a harsh environment for 4392 h, because the impedance of the coating dropped by about 1.4 kΩ.cm². Surface morphological study of metallic specimens before and after exposing to the simulated marine environment (3 wt % NaCl) was carried out using scanning electron microscopy, energy dispersive spectroscopy (EDS), and optical microscope (OM) methods. The interactions between DGEBA-polyaminoamide and the metallic surface were further carried out using computation modeling such as density functional theory (DFT)-based quantum chemical calculations, Monte Carlo (MC), and molecular dynamics (MD) simulations. Results showed that DGEBA-polyaminoamide possesses a strong tendency to adhere and inhibits the corrosive dissolution of 15CDV6 steel surface in the stimulated marine environment. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48402.     

Special Issue on: Towards a “Smart Society” Through Digital and Wireless Communication Technology

Wireless Personal Communications -     

Effect of Intercritical Annealing Time on the Microstructure and Mechanical Properties of Dual-Phase Steel Processed by Large-Strain Asymmetric Cold-Rolling

Herein, the effect of intercritical annealing time on the microstructure and mechanical properties of dual-phase steel processed by large-strain asymmetric cold-rolling is studied. It is observed that the martensite islands are uniformly distributed in the ferrite phase in the microstructures of dual-phase steels due to performing the asymmetric cold-rolling before intercritical annealing treatment. As the intercritical annealing time increases up to 10 min, the fraction of martensite increases. By increasing the holding time and fraction of martensite, the carbon content of the martensite phase is decreased. The short-term intercritical annealing eliminates the yield point phenomenon. However, intercritical annealing at 860 °C for 20 min leads to the reoccurrence of a yield point phenomenon. Increasing the intercritical annealing time to 10 min improves the yield strength to 505 MPa and ultimate tensile strength to 834 MPa. However, the strength decreases sharply after the holding time of 20 min. There is a perfect linear relationship between the mechanical properties and the fraction of martensite. Ductile failure is observed at the center of the fracture surfaces of dual-phase steels while shear failure occurs at the edges of the fracture surfaces.     

Current Strategies for the Regeneration of Skeletal Muscle Tissue

Traumatic injuries, tumor resections, and degenerative diseases can damage skeletal muscle and lead to functional impairment and severe disability. Skeletal muscle regeneration is a complex process that depends on various cell types, signaling molecules, architectural cues, and physicochemical properties to be successful. To promote muscle repair and regeneration, various strategies for skeletal muscle tissue engineering have been developed in the last decades. However, there is still a high demand for the development of new methods and materials that promote skeletal muscle repair and functional regeneration to bring approaches closer to therapies in the clinic that structurally and functionally repair muscle. The combination of stem cells, biomaterials, and biomolecules is used to induce skeletal muscle regeneration. In this review, we provide an overview of different cell types used to treat skeletal muscle injury, highlight current strategies in biomaterial-based approaches, the importance of topography for the successful creation of functional striated muscle fibers, and discuss novel methods for muscle regeneration and challenges for their future clinical implementation.     

Characterization of Critical Determinants of ACE2–SARS CoV-2 RBD Interaction

Despite sequence similarity to SARS-CoV-1, SARS-CoV-2 has demonstrated greater widespread virulence and unique challenges to researchers aiming to study its pathogenicity in humans. The interaction of the viral receptor binding domain (RBD) with its main host cell receptor, angiotensin-converting enzyme 2 (ACE2), has emerged as a critical focal point for the development of anti-viral therapeutics and vaccines. In this study, we selectively identify and characterize the impact of mutating certain amino acid residues in the RBD of SARS-CoV-2 and in ACE2, by utilizing our recently developed NanoBiT technology-based biosensor as well as pseudotyped-virus infectivity assays. Specifically, we examine the mutational effects on RBD-ACE2 binding ability, efficacy of competitive inhibitors, as well as neutralizing antibody activity. We also look at the implications the mutations may have on virus transmissibility, host susceptibility, and the virus transmission path to humans. These critical determinants of virus–host interactions may provide more effective targets for ongoing vaccines, drug development, and potentially pave the way for determining the genetic variation underlying disease severity.     

Fabrication of fibrous poly (ɛ-caprolactone) nano-fibers containing cerium doped-bioglasses nanoparticles encapsulated collagen

Novel nanosized designed ceramic powders, cerium (Ce) doped bioglass (BG) with various doped Ce content, were synthesized by sol–gel method in order to be employed in the development of PCL fibrous scaffold for bone tissue engineering applications. Characterization techniques such as X-ray diffraction analysis, transmission electron microscopy, Fourier transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy were employed to evaluate the developed Ce doped BG powders. The results confirmed successful doping of Ce inside BG structure. 0, 1, 3, and 10 wt% Ce doped 58S BG were successfully encapsulated in the collagen microspheres by water-in-oil emulsion method and the average particle size and hydrodynamic diameter of microspheres were determined using scanning electron microscopy and dynamic light scattering analysis, respectively. Next, 0, 1, 3, and 10 wt% Ce doped 58S BG encapsulated collagen microspheres were loaded inside the Poly(ɛ-caprolactone) fibrous scaffold and their in vitro bioactivity and biocompatibility properties were evaluated. The results of soaking samples in the simulated body fluid showed that all Ce doped 58S BG encapsulated collagen microspheres loaded PCL fibrous scaffold have acceptable bioactivity and apatite formation ability over time. The biocompatibility evaluation of developed scaffolds showed high viability and proliferation of MG63 cells cultured on the surface of 3% Ce doped 58S BG encapsulated collagen microsphere loaded in the PCL fibrous scaffold and its high potential ability for bone tissue engineering applications. These results potentially open new aspects for scaffolds aimed at the regeneration of bone defects.     

Elaboration of porosity for the alumina particle surfaces/ bimodal PP composite cast films under continuous stretching

Efforts have been focused on developing an interrelationship between machine direction orientation (MDO)/material variables and the porosity of Al₂O₃ particulate-filled orientable PP for various applications. Composite films were prepared by cast-extrusion followed by stretching up to 100% and 200% by the MDO machine. Cavitation could occur during film stretching when the adhesion between dispersed alumina and continuous polypropylene phase failed. Composite films with modified micro-particles and also nano ones could not generate any voids. On the other hand, composite specimens of unmodified micro-alumina particles generated micro-pores in the joint between dispersed particles and polymer during the hot stretching. Beta nucleation in these films, plays an important role in the generated ductility of the specimens. Cavitation effectiveness (no. of voids) or film permeability depended on the size and amount of alumina particles, in addition to the ratio and temperature of stretching. Cavitation particles with a size range of 0.7–3 μm, create cavities of about 3–7 μm. Generation of voids, by drawing environmentally friendly and antimicrobial active alumina particles, can be utilized in the fabrication of sustainable hygiene polypropylene films with desirable separation abilities for gases or small molecules. Furthermore, the polypropylene/alumina composite films have the potential for microwaveable packaging.     

Evaluation of fish meat noodles: physical property,dough rheology,chemistry and water distribution properties

The present study reports the rheological, textural, structural and water distribution properties of fish meat noodles. The results showed that storage and loss modulus were increased when 20% fish meat was added while decreased with the addition of >20% fish meat, whereas loss rate behaved vice versa. The moisture and fat content increased significantly (P < 0.05) while water absorption index was decreased upon the increment of fish meat compared to control. Lightness of dough and hardness of noodles decreased significantly (P < 0.05) while redness and yellowness were increased. Similarly, less swelled starch granules and dominancy of protein network over starch granules were observed in microstructure. The amount of free water was increased while bound water was decreased when >20% fish meat was added during low-field nuclear magnetic resonance. The findings suggest the feasibility of adding 15–20% fish meat for the proper structure and chemistry of noodles.