In this chapter, we will restrict our attention to the ferrites and a few other closely related materials. The great interest in ferrites stems from their unique combination of a spontaneous magnetization and a high electrical resistivity. The observed magnetization results from the difference in the magnetizations of two non-equivalent sub-lattices of the magnetic ions in the crystal structure. Materials of this type should strictly be designated as “ferrimagnetic” and in some respects are more closely related to anti-ferromagnetic substances than they are to ferromagnetics in which the magnetization results from the parallel alignment of all the magnetic moments present. We shall not adhere to this special nomenclature except to emphasize effects, which are due to the existence of the sub-lattices.

Ferromagnetic materials

As the field of nanomedicine emerges, there is a lag in research surrounding the topic of nanoparticle (NP) toxicity, particularly concerned with mechanisms of action. The continuous emergence of bacterial resistance has challenged the research community to develop novel antibiotic agents. Metal NPs are among the most promising of these because show strong antibacterial activity. This review summarizes and discusses proposed mechanisms of antibacterial action of different metal NPs. These mechanisms of bacterial killing include the production of reactive oxygen species, cation release, biomolecule damages, ATP depletion, and membrane interaction. Finally, a comprehensive analysis of the effects of NPs on the regulation of genes and proteins (transcriptomic and proteomic) profiles is discussed.

https://link.springer.com/content/pdf/10.1186/s12951-017-0308-z.pdf

Metal nanoparticles: understanding the mechanisms behind antibacterial activity.

Fundamentals and advances in magnesium alloy corrosion

Multi-drug resistance is a growing problem in the treatment of infectious diseases and the widespread use of broad-spectrum antibiotics has produced antibiotic resistance for many human bacterial pathogens. Advances in nanotechnology have opened new horizons in nanomedicine, allowing the synthesis of nanoparticles that can be assembled into complex architectures. Novel studies and technologies are devoted to understanding the mechanisms of disease for the design of new drugs, but unfortunately infectious diseases continue to be a major health burden worldwide. Since ancient times, silver was known for its anti-bacterial effects and for centuries it has been used for prevention and control of disparate infections. Currently nanotechnology and nanomaterials are fully integrated in common applications and objects that we use every day. In addition, the silver nanoparticles are attracting much interest because of their potent antibacterial activity. Many studies have also shown an important activity of silver nanoparticles against bacterial biofilms. This review aims to summarize the emerging efforts to address current challenges and solutions in the treatment of infectious diseases, particularly the use of nanosilver antimicrobials.

/pdf/silver-nanoparticles-as-potential-antibacterial-agents-2in1wnh11h.pdf

Silver nanoparticles as potential antibacterial agents.

Multidrug resistance of the pathogenic microorganisms to the antimicrobial drugs has become a major impediment toward successful diagnosis and management of infectious diseases. Recent advancements in nanotechnology-based medicines have opened new horizons for combating multidrug resistance in microorganisms. In particular, the use of silver nanoparticles (AgNPs) as a potent antibacterial agent has received much attention. The most critical physico-chemical parameters that affect the antimicrobial potential of AgNPs include size, shape, surface charge, concentration and colloidal state. AgNPs exhibits their antimicrobial potential through multifaceted mechanisms. AgNPs adhesion to microbial cells, penetration inside the cells, ROS and free radical generation, and modulation of microbial signal transduction pathways have been recognized as the most prominent modes of antimicrobial action. On the other side, AgNPs exposure to human cells induces cytotoxicity, genotoxicity and inflammatory response in human cells in a cell-type dependent manner. This has raised concerns regarding use of AgNPs in therapeutics and drug delivery. We have summarized the emerging endeavors that address current challenges in relation to safe use of AgNPs in therapeutics and drug delivery platforms. Based on research done so far, we believe that AgNPs can be engineered so as to increase their efficacy, stability, specificity, biosafety and biocompatibility. In this regard, three perspectives research directions have been suggested that include 1) synthesizing AgNPs with controlled physico-chemical properties, 2) examining microbial development of resistance towards AgNPs, and 3) ascertaining the susceptibility of cytoxicity, genotoxicity, and inflammatory response to human cells upon AgNPs exposure.

/pdf/mechanistic-basis-of-antimicrobial-actions-of-silver-1vmm44o6it.pdf

Mechanistic Basis of Antimicrobial Actions of Silver Nanoparticles.

Grain Refining Mechanism in the Al/Al-Ti-B System

Corrosion of AA2024-T3 Part II: Co-operative corrosion

The anodic oxidation of aluminium alloys is reviewed and discussed with reference to recent results of the authors on the anodizing of model binary aluminium alloys. Attention is given primarily to...

Effects of Alloying Elements in Anodizing of Aluminium

Release of silver and copper nanoparticles from polyethylene nanocomposites and their penetration into Listeria monocytogenes

Oxide films grown anodically at the surface of superpure aluminium are used as standards to assess the accuracy of the thickness (d XPS ) determined using the Beer-Lambert treatment of the Al 2p metal and oxide peak intensities. For the fitting conditions employed, the value of d XPS is found to be very close to the true film thickness for films <10 nm thick, beyond which imprecise values are obtained. A surface layer of hydration is identified from the curve fitting of the O is core level, which would qualitatively account for the slight underestimate of film thickness provided by the expression for d XPS . The validity of the Al 2p fit may be determined through this correlation of thickness but requires first a quantitative assessment of the thickness and composition of the hydroxide-rich layer.

Xiaorong Zhou

Papers

Grain Refining Mechanism in the Al/Al-Ti-B System

Corrosion of AA2024-T3 Part II: Co-operative corrosion

Effects of Alloying Elements in Anodizing of Aluminium

Release of silver and copper nanoparticles from polyethylene nanocomposites and their penetration into Listeria monocytogenes

Quantification of oxide film thickness at the surface of aluminium using XPS