78 results match your criteria: "Centre for Nanostructures and Advanced Materials[Affiliation]"

In this study, the influences of natural fibres (sugarcane bagasse (SB) and sawdust (SD)) on the material properties of polybutylene succinate (PBS) prepared through melt compounding were investigated. The study further evaluated the effects of incorporating halloysite nanotubes (HS) and expandable graphite (EG) on the properties of PBS/SD and PBS/SB binary and PBS/SB/SD hybrid composites. The morphological analysis indicated poor interfacial adhesion between PBS and the fibres.

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Microbeads of raspberry extract were produced using encapsulation matrices alginate + pea protein isolate + , alginate + pea protein isolate + + okra, and alginate + pea protein isolate + + gel + gallic acid using freeze-drying method. The microbeads were characterised and assessed for their effectiveness on the release, bioaccessibility, of anthocyanin components and antioxidant activities during in vitro digestion. Alginate + pea protein isolate + + gel + gallic acid matrix showed the highest encapsulation efficiency of 91.

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Phytochemical analysis of the dichloromethane-methanol (1:1) extract from inner bark led to the identification of three compounds: a novel glycoside, 3α-sorbithoxyglucose (), and two known compounds, retusasterol () and -sitosterol-3-glycoside (), isolated for the first time from this plant. Structural elucidation NMR confirmed their identities. Cytotoxicity studies against MCF7 breast cancer and DU145, PC3, LNCaP prostate cancer cell lines revealed that compounds and lacked inhibitory effects on cell proliferation, while retusasterol exhibited cytotoxicity with CC values of 38 μg/mL (DU145), 40 μg/mL (PC3), and 32 μg/mL (LNCaP).

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There is a sizeable amount of sawdust produced from wood industries such as timber and furniture. In the past, sawdust has been utilized as a fuel source and in the manufacturing of furniture. Based on the limited use of sawdust, there is plenty of sawdust accessible from the industries.

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Herpes simplex virus type 2 (HSV-2) remains a significant public health concern due to its high rates of mortality and morbidity. While various chemotherapeutic options exist for treating HSV-2, they are often inadequate as none provide a definitive cure, and there is a growing issue of drug-resistant strains. The introduction of nanomedicine for antiviral drug delivery offers a promising avenue to enhance the effectiveness of these treatments.

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Silver(I) phosphine complexes have attracted significant attention recently due to their structural versatility and promising anticancer properties. These complexes exhibit diverse coordination geometries-ranging from tetrahedral and trigonal planar to linear-depending on the ligand environment and metal-to-ligand ratio, directly influencing their biological activity. Notably, they demonstrate substantial cytotoxicity against various cancer cell lines, including oesophageal (SNO), breast (MCF-7), and lung (A549) cancers, with IC₅₀ values in the low micromolar range.

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The desert locust has been recognized as the most devastating migratory pest in the world. Swarms of this pest have been threatening vast regions of pastures and crops in Africa, Middle East, and South Asia. The biological management of expanding swarms has become a strategy of particular interest due to environmental awareness and economic issues associated with chemical pesticides.

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Background/objectives: Loading of natural products into poly-(lactide-co-glycolic) acid (PLGA) nanoparticles as drug delivery systems for the treatment of diseases, such as tuberculosis (TB), has been widely explored. The current study investigated the use of PLGA nanoparticles with 7-methyljuglone (7-MJ), an active pure compound, isolated from the roots of A. DC.

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N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC), a quaternized chitosan derivative, has been shown to exhibit a broad spectrum of antimicrobial activity, especially against bacteria and enveloped viruses. Despite this, molecular docking studies showing its atomic-level mechanisms against these microorganisms are scarce. Here, for the first time, we employed molecular docking analyses to investigate the potential antibacterial activity of HTCC against and its antiviral activity against human immunodeficiency virus 1 (HIV-1).

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Background: Various agricultural sidestreams have been demonstrated as feedstock to produce cellulose. To the best of our knowledge, there is no research work on the potential of agricultural sidestream from cowpea (Vigna unguiculata (L.) Walp.

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Carboxy-PEG-thiol functionalized gold nanoparticle conjugates for the detection of SARS-CoV-2: Detection tools and analytical method development.

J Virol Methods

December 2024

Centre for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology Innovation Centre, Council for Scientific and Industrial Research, Pretoria 0001, South Africa; Department of Chemical Engineering, Faculty of Engineering, Built Environment and Information Technology, University of Pretoria,

Addressing the need for accessible SARS-CoV-2 testing, carboxy-PEG 12-thiol functionalized gold nanoparticles conjugates were developed for rapid point-of-care (POC) detection against SARS-CoV-2 spike protein, pseudo-SARS-CoV-2, and authentic Beta SARS-CoV-2 virus particles. These conjugates leverage gold nanoparticles (AuNPs) as signal transducers, cross-linked to either angiotensin-converting enzyme 2 (ACE2) or SARS-CoV-2 spike protein receptor-binding domain (RBD) antibodies as bioreceptors and showed a distinct color shift from pink to blue. To assess their POC feasibility, the conjugates were integrated into facemasks and breathalyzers, wherein aerosolized SARS-CoV-2 antigens were successfully detected, producing a color change within 10 and 30 minutes for the breathalyzer and facemask prototypes, respectively.

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Nanocellulose-based conductive composites: A review of systems for electromagnetic interference shielding applications.

Int J Biol Macromol

October 2024

Department of Chemical Sciences, University of Johannesburg, Doorfontein, Johannesburg 2028, South Africa; Centre for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology Innovation Centre, Council for Scientific and Industrial Research, Pretoria 0001, South Africa. Electronic address: ssi

Electronic systems and telecommunications have grown in popularity, leading to increasing electromagnetic (EM) radiation pollution. Environmental protection from EM radiation demands the use of environmentally friendly products. The design of EM interference (EMI) shielding materials using resources like nanocellulose (NC) is gaining traction.

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Polymeric materials undergo degradation when exposed to outdoor conditions due to the synergistic effects of sunlight, air, heat, and moisture. The degradation can lead to a decline in mechanical properties, fading, surface cracking, and haziness, attributed to the cleavage of the polymer chains and oxidation reactions. Accelerated weathering testing is a useful technique to evaluate the comparative photodegradation of materials within a reasonable timeframe.

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This study investigates the rheological, morphological, and mechanical properties of melt-processed polylactide/ethylene vinyl alcohol (70PLA/30EVOH) blend composites containing 0.25, 0.5, and 1 wt.

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Background: Metabolism is an important component of the kinetic characteristics of herbal constituents, and it often determines the internal dose and concentration of these effective constituents at the target site. The metabolic profile of plant extracts and pure compounds need to be determined for any possible herb-drug metabolic interactions that might occur.

Methods: Various concentrations of the essential oil of Lippia scaberrima, the ethanolic extract of Lippia scaberrima alone and their combinations with fermented and unfermented Aspalathus linearis extract were used to determine the inhibitory potential on placental, microsomal and recombinant human hepatic Cytochrome P450 enzymes.

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Background: Atopic dermatitis (eczema) is an inflammatory skin condition with synthetic treatments that induce adverse effects and are ineffective. One of the proposed causes for the development of the condition is the outside-in hypothesis, which states that eczema is caused by a disruption in the skin barrier. These disruptions include developing dry cracked skin, which promotes the production of histamine.

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7-Methyljuglone (7-MJ) is a pure compound isolated from the roots of A. DC., a shrub indigenous to South Africa.

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Cannabidiol (CBD) is a high-value natural compound of plant. It is a non-psychotropic phytocannabinoid, attracting significant attention as a multifunctional active ingredient for topical applications. Although it is demonstrated that CBD can be used for specific dermatological ailments, reliable data on functionalities are limited.

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Although most semiconductor metal oxides including InO show acceptable sensitivity to volatile organic compounds, it is difficult to detect ethanol effectively at low operating temperatures and detection levels. In this study, pure and Co-, Ni-, and Cu-doped InO products with their doping content maintained at 1 mol % were successfully produced using a hydrothermal approach. Explicit contrast on the structural, microstructural, and textural properties of the synthesized InO products was examined to determine their gas sensing performance.

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Cationic Chitosan Derivatives for the Inactivation of HIV-1 and SARS-CoV-2 Enveloped Viruses.

ACS Omega

September 2023

Bio-Polymer Modification and Advanced Therapeutics Laboratory, Centre for Nanostructures and Advanced Materials, Council for Scientific and Industrial Research, Pretoria, Gauteng 0001, South Africa.

Cationic chitosan derivatives have been widely studied as potential antimicrobial agents. However, very little is known about their antiviral activity and mode of action against enveloped viruses. We investigated the ability of hydroxypropanoic acid-grafted chitosan (HPA-CS) and -(2-hydroxypropyl)-3-trimethylammonium chitosan chloride (HTCC) to inactivate enveloped viruses like the human immunodeficiency virus (HIV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

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Recent Advances and Outlook in 2D Nanomaterial-Based Flame-Retardant PLA Materials.

Materials (Basel)

September 2023

Department of Chemical Sciences, University of Johannesburg, Doorfontein, Johannesburg 2028, South Africa.

Poly (lactic acid) or polylactide (PLA) has gained widespread use in many industries and has become a commodity polymer. Its potential as a perfect replacement for petrochemically made plastics has been constrained by its extreme flammability and propensity to flow in a fire. Traditional flame-retardants (FRs), such as organo-halogen chemicals, can be added to PLA without significantly affecting the material's mechanical properties.

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This work presents the experimental steps taken towards the preparation of 3D printable bionanocomposites using polylactic acid (PLA) biopolymer containing 0.1, 0.5 and 1 wt% CNCs.

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The development of eco-friendly products to protect the environment has become a topical subject in the research and industrial communities. This is a result of strict environmental regulations necessitating the development of novel strategies to reduce our reliance on petroleum-based products, which exert a negative effect on our ecosystem. Bast-fibre-based hybrids have been extensively studied for various applications due to their eco-friendliness and cost effectiveness.

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Porous structures with sizes between the submicrometer and nanometer scales can be produced using efficient and adaptable electrospinning technology. However, to approximate desirable structures, the construction lacks mechanical sophistication and conformance and requires three-dimensional solitary or multifunctional structures. The diversity of high-performance polymers and blends has enabled the creation of several porous structural conformations for applications in advanced materials science, particularly in biomedicine.

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This review presents fundamental knowledge and recent advances pertaining to research on the role of rheology in polymer processing, highlights the knowledge gap between the function of rheology in various processing operations and the importance of rheology in the development, characterization, and assessment of the morphologies of polymeric materials, and offers ideas for enhancing the processabilities of polymeric materials in advanced processing operations. Rheology plays a crucial role in the morphological evolution of polymer blends and composites, influencing the type of morphology in the case of blends and the quality of dispersion in the cases of both blends and composites. The rheological characteristics of multiphase polymeric materials provide valuable information on the morphologies of these materials, thereby rendering rheology an important tool for morphological assessment.

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