An Application of Microemulsion Method for Synthesis of Copper-Zinc Materials

Pawlonka, Justyna; Słowik, Grzegorz; Gac, Wojciech; Borowiecki, T.

doi:10.2478/umcschem-2013-0009

Cited by 2 publications

(1 citation statement)

References 14 publications

(15 reference statements)

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“…Furthermore, the nanoparticles are prepared by mixing separate microemulsions containing stoichiometric amounts of precursors. Micelles containing reactants solubilised in their cores act as "nano-reactors" where nucleation and growth occur [93]. When two microemulsions are mixed, micelles undergo collisions via Brownian motion resulting in coalescence, fusion, and consequently exchange and mixing of the solubilised reactants, which then react to form crystal nuclei [94,95].…”

Section: Fabrication Of Nanomaterialsmentioning

confidence: 99%

The Luminescence of Lanthanide-doped NaMgF3 Nanoparticles: Radioluminescence, Radiophotoluminescence and Optically Stimulated Luminescence

Nalumaga¹

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NaMgF3 is a host material that has demonstrated luminescent properties suitable for radiation dose measurements when doped with lanthanide (Ln) ions. NaMgF3 has a response to ionising radiation similar to that of tissue, and hence it has potential application in radiotherapy where a high level of accuracy is required. This thesis focused on investigations into the suitability of NaMgF3 nanoparticles for radiation dose measurements. Nanoparticles display advantages that can be exploited to increase spatial resolution in two-dimensional dosimetry. Additionally, nanoparticles exhibit new and different distributions of optically active traps, and their luminescence can be sensitised to increase the signal to noise. Hence, this thesis presents results obtained from the synthesis and characterisation of Ln-doped NaMgF3 nanoparticles. The nanoparticles were synthesised via the hydrothermal, reverse micelle and thermolysis techniques. Structural studies were carried out, followed by investigations on the effect of X-ray irradiation on the luminescent properties of the nanoparticles. It was observed that compared to the bulk materials, the nanoparticles exhibited increased oxygen (O2-)-related defect luminescence and favoured substitution of trivalent ions over the divalent ions. The behaviour was attributed to the stability of trivalent ions in aqueous solutions during nanoparticle synthesis, which encouraged increased incorporation of O2--related defects to create charge neutrality. O2--related defects allowed for O2- → Yb3+ charge transfer process, hence Yb3+ emission in the infrared region. X-ray stimulation resulted in Yb3+ → Yb2+ radiophotoluminescence (RPL), but the increase in Yb-dopant concentration revealed no significant effect on the structural and luminescent properties. Most of the studied materials exhibited multiple luminescence properties for monitoring radiation doses, which would increase the dose accuracy. Ce-doped nanoparticles exhibited the first reported optically stimulated luminescence (OSL) in Ln-doped near tissue-equivalent NaMgF3 nanoparticles suitable for total radiation measurements. OSL occurred through a series of processes, including the creation of F-centres through X-ray irradiation and optical stimulation to release electrons that recombined with holes trapped at Ce4+ sites, followed by Ce3+ emission. In addition, the Ce3+ → Ce4+ RPL effect suitable for cumulative radiation monitoring was observed from isolated and aggregated Ce3+ sites in the Ce-doped nanoparticles, providing an additional method to increase dose accuracy. Furthermore, the Ce,Sm co-doped NaMgF3 nanoparticles demonstrated suitability for real-time and cumulative radiation dose monitoring via Sm radioluminescence after a priming dose and multiple Ce3+ → Ce4+, Sm3+ → Sm2+, and O2- → O- RPL signals through which cumulative radiation doses can be determined. Finally, the applicability of singly doped oleic acid-capped NaMgF3:Eu and NaMgF3:Sm nanoparticles for radiation monitoring via the Eu3+ → Eu2+ and Sm3+ → Sm2+ RPL effects were demonstrated. The studies were followed by investigations of the sensitisation of Eu3+ and Sm3+ luminescence signals using 2-thenoyltrifluoroacetone (TTFA). The first successful sensitisation of NaMgF3 nanoparticles was demonstrated through remarkable TTFA → Eu3+ energy transfer. However, minimal TTFA → Sm3+ sensitisation was observed, attributable to a non-optimal energy difference between the TTFA triplet state and the Sm3+ resonance energy level, encouraging back energy transfer. TTFA → O2- sensitisation was additionally observed in the NaMgF3:Sm nanoparticles. Furthermore, enhancement of Sm3+ luminescence was additionally demonstrated in the Ce,Sm co-doped nanoparticles via energy transfer from the Ce3+ fully allowed 4f → 5d transitions. The studies resulted in a wealth of information, and where possible, detailed schematic models are presented to explain the observations, which will guide future research. Ultimately, nanoparticles display luminescent properties suitable for dosimetry applications, and the results encouraged further research into the application of nanoparticles as dosimeter materials.

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Section: Fabrication Of Nanomaterialsmentioning

confidence: 99%

The Luminescence of Lanthanide-doped NaMgF3 Nanoparticles: Radioluminescence, Radiophotoluminescence and Optically Stimulated Luminescence

Nalumaga¹

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Tea tree (Melaleuca alternifolia) Essential Oil Concentration in Microemulsion with Antibacterial and Antifungal Activity: An Overview

Upadhyay

Malik

Upadhyay

2023

CDTH

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1: The tea tree (Melaleuca alternifolia), a member of the Myrtaceae family, is a valuable medicinal and aromatic plant. Tea Tree essential oil (TTO) has many medical applications, including antibacterial, antifungal, antiviral, antiprotozoal, anti-inflammatory, antioxidant, and anticancer properties. Although the concentration of TTO in a microemulsion is of economic interest, very few studies on this product have been conducted. In this study, we look at how different tea tree oil concentrations in microemulsion formulations affect susceptibility to various bacteria and fungi. TTO susceptibility in a diverse range of microbial species has now been studied using data from a previously published literature review survey. Most bacteria are resistant to TTO at concentrations as low as 1.0 percent, but mucosal skin staphylococci and micrococci, Enterococcus faecalis, and Pseudomonas aeruginosa have minimum inhibitory concentrations much higher than 2 percent. TTO susceptibility in fungi has only recently been scrutinized. Fungicidal dosages range from 0.12 to 2 percent, with minimum inhibitory concentrations ranging from 0.03 to 0.5 percent and the only notable exception is Aspergillus niger, which contains fungicidal concentrations of up to 8%. The review emphasizes the importance of new antibacterial and antifungal formulations, as well as the role of natural essential oils in the discovery of new antibacterial and antifungal agents, and discusses, in brief, all constituents derived from the essential oil (tea tree) that are in preclinical and clinical development. This paper summarizes human and food-borne bacteria and fungi susceptibility to tea tree essential oils and their constituents. Among the many tested, essential oils of spices and herbs (Melaleuca alternifolia) were found to have the strongest antimicrobial properties. This review looks at a wide range of scientific literature, including Sci-hub, Google Scholar, Pub, Chem, NCBI, and web books.

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An Application of Microemulsion Method for Synthesis of Copper-Zinc Materials

Cited by 2 publications

References 14 publications

The Luminescence of Lanthanide-doped NaMgF3 Nanoparticles: Radioluminescence, Radiophotoluminescence and Optically Stimulated Luminescence

The Luminescence of Lanthanide-doped NaMgF3 Nanoparticles: Radioluminescence, Radiophotoluminescence and Optically Stimulated Luminescence

Tea tree (Melaleuca alternifolia) Essential Oil Concentration in Microemulsion with Antibacterial and Antifungal Activity: An Overview

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