Ultrasonic, molecular and mechanical testing diagnostics in natural fibre reinforced, polymer-stabilised earth blocks

The aim of this research study was to evaluate the influence of utilising natural polymers as a form of soil stabilization, in order to assess their potential for use in building applications. Mixtures were stabilized with a natural polymer (alginate) and reinforced with wool fibres in order to improve the overall compressive and flexural strength of a series of composite materials. Ultrasonic pulse velocity (UPV) and mechanical strength testing techniques were then used to measure the porous properties of the manufactured natural polymer-soil composites, which were formed into earth blocks. Mechanical tests were carried out for three different clays which showed that the polymer increased the mechanical resistance of the samples to varying degrees, depending on the plasticity index of each soil. Variation in soil grain size distributions and Atterberg limits were assessed and chemical compositions were studied and compared. X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), and energy dispersive X-ray fluorescence (EDXRF) techniques were all used in conjunction with qualitative identification of the aggregates. Ultrasonic wave propagation was found to be a useful technique for assisting in the determination of soil shrinkage characteristics and fibre-soil adherence capacity and UPV results correlated well with the measured mechanical properties

A combination of SEM and EDX studies on a clay-based natural composite with animal fibre and its mechanical implications

A variety of natural fibres are nowadays being utilized as soil reinforcement. Test results demonstrate the positive effects of adding natural fibres to soils, in that they decrease shrinkage, reduce curing time and enhance compressive, flexural and shear strength if an optimum reinforcement ratio can be utilised. This paper describes a study which uses a Scanning Electron Microscope (SEM) and an Energy Diffraction Analysis of X-rays (EDX) technique on clay-based composites stabilized with natural polymer and fibres. Different dosages of fibres and several types of soils have been used in this study with the aim of determining advantageous properties for building material applications. SEM and EDX test results reveal the degree of bonding between the particles of soil and the natural fibers. This has enabled a better understanding of the micro-morphology of the natural fibers and their effect on the overall composite material structure. Microscopic analysis was combined with mechanical tests to establish the different strength characteristics of every soil

Ultrasonic, molecular and mechanical testing diagnostics in natural fibre reinforced, polymer-stabilised earth blocks

The aim of this research study was to evaluate the influence of utilising natural polymers as a form of soil stabilization, in order to assess their potential for use in building applications. Mixtures were stabilized with a natural polymer (alginate) and reinforced with wool fibres in order to improve the overall compressive and flexural strength of a series of composite materials. Ultrasonic pulse velocity (UPV) and mechanical strength testing techniques were then used to measure the porous properties of the manufactured natural polymer-soil composites, which were formed into earth blocks. Mechanical tests were carried out for three different clays which showed that the polymer increased the mechanical resistance of the samples to varying degrees, depending on the plasticity index of each soil. Variation in soil grain size distributions and Atterberg limits were assessed and chemical compositions were studied and compared. X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), and energy dispersive X-ray fluorescence (EDXRF) techniques were all used in conjunction with qualitative identification of the aggregates. Ultrasonic wave propagation was found to be a useful technique for assisting in the determination of soil shrinkage characteristics and fibre-soil adherence capacity and UPV results correlated well with the measured mechanical properties

Fluorescent carbon dots from mono- and polysaccharides:synthesis, properties and applications

Fluorescent carbon dots (FCDs) are an emerging class of nanomaterials made from carbon sources that have been hailed as potential non-toxic replacements to traditional semiconductor quantum dots (QDs). Particularly in the areas of live imaging and drug delivery, due to their water solubility, low toxicity and photo- and chemical stability. Carbohydrates are readily available chiral biomolecules in nature which offer an attractive and cheap starting material from which to synthesise FCDs with distinct features and interesting applications. This mini-review article will cover the progress in the development of FCDs prepared from carbohydrate sources with an emphasis on their synthesis, functionalization and technical applications, including discussions on current challenges

Photoresponsive Control of G-Quadruplex DNA Systems

[Image: see text] G-quadruplex (G4) oligonucleotide secondary structures have recently attracted significant attention as therapeutic targets owing to their occurrence in human oncogene promoter sequences and the genome of pathogenic organisms. G4s also demonstrate interesting catalytic activities in their own right, as well as the ability to act as scaffolds for the development of DNA-based materials and nanodevices. Owing to this diverse range of opportunities to exploit G4 in a variety of applications, several strategies to control G4 structure and function have emerged. Interrogating the role of G4s in biology requires the delivery of small-molecule ligands that promote its formation under physiological conditions, while exploiting G4 in the development of responsive nanodevices is normally achieved by the addition and sequestration of the metal ions required for the stabilization of the folded structure. Although these strategies prove successful, neither allows the system in question to be controlled externally. Meanwhile, light has proven to be an attractive means for the control of DNA-based systems as it is noninvasive, can be delivered with high spatiotemporal precision, and is orthogonal to many chemical and biological processes. A plethora of photoresponsive DNA systems have been reported to date; however, the vast majority deploy photoreactive moieties to control the stability and assembly of duplex DNA hybrids. Despite the unique opportunities afforded by the regulation of G-quadruplex formation in biology, catalysis, and nanotechnology, comparatively little attention has been devoted to the design of photoresponsive G4-based systems. In this Perspective, we consider the potential of photoresponsive G4 assemblies and examine the strategies that may be used to engineer these systems toward a variety of applications. Through an overview of the main developments in the field to date, we highlight recent progress made toward this exciting goal and the emerging opportunities that remain ripe for further exploration in the coming years

Reengineering of cancer cell surface charges can modulate cell migration

The ability to modulate the cell surface structure provides a powerful tool to understand fundamental processes and also to elicit desired cellular responses. Here we report the development of a new class of ‘clickable labels’ to reengineer the cell surface charges of live cells. The method relies on the use of metabolic oligosaccharide engineering (MOE) combined with chemo selective labeling of cell surface azido-containing sialic acids with dibenzocyclooctyne (DBCO) ionic-probes. Using this strategy, we demonstrate that reducing the negative charge induced by the overexpression of cell surface sialic acids in cancer cells leads to a reduction in cell migration without affecting drug supceptibility

Carbon Dots as an Emergent Class of Antimicrobial Agents

Antimicrobial resistance is a recognized global challenge. Tools for bacterial detection can combat antimicrobial resistance by facilitating evidence-based antibiotic prescribing, thus avoiding their overprescription, which contributes to the spread of resistance. Unfortunately, traditional culture-based identification methods take at least a day, while emerging alternatives are limited by high cost and a requirement for skilled operators. Moreover, photodynamic inactivation of bacteria promoted by photosensitisers could be considered as one of the most promising strategies in the fight against multidrug resistance pathogens. In this context, carbon dots (CDs) have been identified as a promising class of photosensitiser nanomaterials for the specific detection and inactivation of different bacterial species. CDs possess exceptional and tuneable chemical and photoelectric properties that make them excellent candidates for antibacterial theranostic applications, such as great chemical stability, high water solubility, low toxicity and excellent biocompatibility. In this review, we will summarize the most recent advances on the use of CDs as antimicrobial agents, including the most commonly used methodologies for CD and CD/composites syntheses and their antibacterial properties in both in vitro and in vivo models developed in the last 3 years.Peer reviewe