Principles and prospects of high-energy magnesium-ion batteries

In the last decade or so, lithium batteries have gained important niche positions in the market for electrochemical storage systems. Their energy capacities per unit weight (or volume) are remarkably better than those of traditional batteries – yet they appear to be approaching their practical limit, and alternative cell systems are under active investigation. The potential advantages of replacing lithium by magnesium have long been recognised, but for years it was thought that materials limitations and technical problems would prevent them from being realised. However, a combination of commercial pressures and recent scientific breakthroughs has made it likely that magnesium batteries will soon be available for a wide range of applications; they are expected to be cheaper and safer than those based on lithium, with comparable performance. This article briefly reviews the current situation and looks at the general background, principles and cell components, outlining some of the technical problems and discussing some promising materials for magnesium-ion batteries. </jats:p

Have mirror micrometeorites been detected?

Slow-moving ($v \sim 15$ km/s) 'dark matter particles' have allegedly been discovered in a recent experiment. We explore the possibility that these slow moving dark matter particles are small mirror matter dust particles originating from our solar system. Ways of further testing our hypothesis, including the possibility of observing these dust particles in cryogenic detectors such as NAUTILUS, are also discussed.Comment: Few changes, about 8 pages lon

Side-chain liquid crystal conducting polymers

This article overviews some of the research progress on the effects of incorporating liquid crystalline functionalities into commercial conjugated polymers such as polythiophene, polypyrrole and polyaniline. Polarisable aromatic mesogens are generally attached via a flexible spacer group to the monomers to form a side-chain. Consequently, the self-organising properties of liquid crystals can be used to influence the conducting polymer backbone and control the electrical, magnetic and mechanical properties of the material. Some applications of these interesting materials are discussed. </jats:p

Surface perfluoroalkyl chains segregation : a tool for reducing calcium deposits in medical grade poly(methyl methacrylate)

Intraocular lenses can be manufactured from a wide variety of polymers, but due to the lost cost associated with the use of Poly(methyl methacrylate) (PMMA), it is still the preferred material used in the developing countries. However, a major drawback to its use is the build-up of calcium containing deposits that are formed on the intraocular lens over a period of time. In an attempt to hinder this deposition, surface modification of medical grade PMMA has been carried out using perfluoroalkyl chain (1,2,4-trifluoro-3- (C10F21CH2O)-7-(N,N)-dimethylaminoacridine) segregation. The segregation was explored using a 1% 1,2,4-trifluoro-3-(C10F21CH2O)-7-(N,N)-dimethyla- minoacridine in two methods: film casting and spin-coating, a thin film onto preformed PMMA discs. Both methods were compared against control PMMA to determine which method provided the best hindrance against calcium containing deposits when immersed in a simulated aqueous humour solution. Characterisation of the surface using scanning electron microscopy coupled with energy; dispersive x-ray analysis indicated that the surface segregation of perfluoroalkyl chains had hindered calcification in both methods. This pleminary research shows promising results of employing perfluoroalkyl chains in the surface segregation of biomaterials that can be employed in intraocular lenses

Overcoming the blood-brain barrier : functionalised chitosan nanocarriers

The major impediment to the delivery of therapeutics to the brain is the presence of the blood-brain barrier (BBB). The BBB allows for the entrance of essential nutrients while excluding harmful substances, including most therapeutic agents; hence, brain disorders, especially tumours, are very difficult to treat. Chitosan is a well-researched polymer that offers advantageous biological and chemical properties, such as mucoadhesion and the ease of functionalisation. Chitosan-based nanocarriers (CsNCs) establish ionic interactions with the endothelial cells, facilitating the crossing of drugs through the BBB by adsorptive mediated transcytosis. This process is further enhanced by modifications of the structure of chitosan, owing to the presence of reactive amino and hydroxyl groups. Finally, by permanently binding ligands or molecules, such as antibodies or lipids, CsNCs have showed a boosted passage through the BBB, in both in vivo and in vitro studies which will be discussed in this review

Advances in chitosan-based CRISPR/Cas9 delivery systems

Clustered regularly interspaced short palindromic repeat (CRISPR) and the associated Cas endonuclease (Cas9) is a cutting-edge genome-editing technology that specifically targets DNA sequences by using short RNA molecules, helping the endonuclease Cas9 in the repairing of genes responsible for genetic diseases. However, the main issue regarding the application of this technique is the development of an efficient CRISPR/Cas9 delivery system. The consensus relies on the use of non-viral delivery systems represented by nanoparticles (NPs). Chitosan is a safe biopolymer widely used in the generation of NPs for several biomedical applications, especially gene delivery. Indeed, it shows several advantages in the context of gene delivery systems, for instance, the presence of positively charged amino groups on its backbone can establish electrostatic interactions with the negatively charged nucleic acid forming stable nanocomplexes. However, its main limitations include poor solubility in physiological pH and limited buffering ability, which can be overcome by functionalising its chemical structure. This review offers a critical analysis of the different approaches for the generation of chitosan-based CRISPR/Cas9 delivery systems and suggestions for future developments

Synthesis and properties of an N-substituted polypyrrole with liquid crystalline moieties

The synthesis and characterisation of two pyrrole monomers substituted at the N-position with a liquid crystal group are reported. Polymerisation of one of these compounds produced a soluble liquid crystalline semiconducting polymer. The side-chain of the polymer had a flexible spacer of nine methylene units, terminated by a mesogenic cyanobiphenyl group. The new compounds were chemically characterised and were found by hot-stage polarised optical microscopy to exhibit liquid crystal mesophases. The polymer was lightly doped p-type by exposure to iodine vapour, and its electrical conductivity was measured. The polymer synthesis and doping/dedoping processes were also briefly studied by cyclic voltammetry