Sonochemical preparation of pure t-LaVO4 nanoparticles with the aid of tris(acetylacetonato)lanthanum hydrate as a novel precursor

Herein a simple and fast method is introduced for the synthesis of lanthanum orthovanadate (LaVO₄) nanoparticles under ultrasound irradiation. The effect of tris(acetylacetonato)lanthanum hydrate ([La(acac)₃·3H₂O]) and La(OAc)₃ as two different precursors on the morphology and phase purity of LaVO₄ was investigated. To optimum the particle size of the products, sonication time and the kind of surfactants have been changed. The as-synthesized products were characterized by XRD, FT-IR, SEM, TEM, and EDS. Based on the obtained results, it was found that the size and shape of the sonochemically formed LaVO₄ nanoparticles were dramatically dependent on the sonication time, type of surfactant and lanthanum precursor. According to the XRD results, it was observed that pure tetragonal phase lanthanum orthovanadate (t-LaVO₄) could be obtained only by using [La(acac)₃·3H₂O] as precursor under ultrasound irradiation for 30 min. On the other hand, monoclinic phase lanthanum orthovanadate (m-LaVO₄) with poor crystallinity has been produced by vigorous stirring at room temperature without sonication.     

Numerical simulation of ultrasonic enhancement on mass transfer in liquid–solid reaction by a new computational model

Mass transfer coefficient is an important parameter in the process of mass transfer. It can reflect the degree of enhancement of mass transfer process in liquid–solid reaction and in non-reactive systems like dissolution and leaching, and further verify the issues by experiments in the reaction process. In the present paper, a new computational model quantitatively solving ultrasonic enhancement on mass transfer coefficient in liquid–solid reaction is established, and the mass transfer coefficient on silicon surface with a transducer at frequencies of 40 kHz, 60 kHz, 80 kHz and 100 kHz has been numerically simulated. The simulation results indicate that mass transfer coefficient increases with the increasing of ultrasound power, and the maximum value of mass transfer coefficient is 1.467 × 10⁻⁴ m/s at 60 kHz and the minimum is 1.310 × 10⁻⁴ m/s at 80 kHz in the condition when ultrasound power is 50 W (the mass transfer coefficient is 2.384 × 10⁻⁵ m/s without ultrasound). The extrinsic factors such as temperature and transducer diameter and distance between reactor and ultrasound source also influence the mass transfer coefficient on silicon surface. Mass transfer coefficient increases with the increasing temperature, with the decreasing distance between silicon and central position, with the decreasing of transducer diameter, and with the decreasing of distance between reactor and ultrasound source at the same ultrasonic power and frequency. The simulation results indicate that the computational model can quantitatively solve the ultrasonic enhancement on mass transfer coefficient.     

Physicochemical properties of peanut protein isolate–glucomannan conjugates prepared by ultrasonic treatment

Peanut protein isolate (PPI) was glycated with glucomannan through classical heating or ultrasound treatment in this work. The physicochemical properties of PPI–glucomannan conjugates prepared by ultrasound treatment were compared to those prepared by classical heating. Compared with classical heating, ultrasound treatment could accelerate the graft reaction between PPI and glucomannan and improve the concentration of available free amino groups of PPI. Solubility and emulsifying properties of the conjugates obtained by ultrasound treatment were both improved as compared to those obtained by classical heating and native PPI. Decreases of lysine and arginine contents during the graft reaction indicated that these two amino acid residues attended the covalent linkage between PPI and glucomannan. Structural feature analyses suggested that conjugates obtained by ultrasound treatment had less α-helix, more β-structures and random coil, higher surface hydrophobicity and less compact tertiary structure as compared to those obtained by classical heating and native PPI.     

Multifunctional magnetic nanoparticles for magnetic resonance image-guided photothermal therapy for cancer

Key advances in multifunctional magnetic nanoparticles （MNPs） for magnetic resonance （MR） image-guided pho- tothermal therapy of cancer are reviewed. We briefly outline the design and fabrication of such multifunctional MNPs. Bimodal image-guided photothermal therapies （MR/fluorescence and MR/ultrasound） are also discussed.     

Multi-objective optimisation of positively homogeneous functions and an application in radiation therapy

Unconstrained multi-objective optimisation problems with p$p$ positively homogeneous objective functions are considered. We prove that such problems reduce to multi-objective optimisation problems with p−1$p-1$ objectives and a single equality constraint. Thus, problems with two objectives can be solved with standard single objective optimisation methods and, for problems with p>2$p>2$ objectives, we can compute infinitely many efficient solutions by solving a finite number of single objective problems. The proposed procedure is applied on radiotherapy for cancer treatment.     

Submicron Size Formulation of Linseed Oil Containing Omega-3 Fatty Acid for Topical Delivery

The aim of the present study was to design and develop topical submicron size gel formulation of linseed oil with enhanced permeation through the skin for the management of psoriasis. Linseed oil contains significant amount of α-linolenic acid (ALA) an omega-3 fatty acid, which is responsible for its pharmacological actions. In order to enhance permeation through skin, microemulsion based gel formulation was prepared and characterized. Microemulsions were prepared by aqueous phase titration method, using linseed oil, Unitop 100, PEG 400, and distilled water as the oil phase, surfactant, cosurfactant and aqueous phase, respectively. Selected formulations were subjected to physical stability studies and consequently in vitro skin permeation studies. Surface morphology studies of optimized formulation were done by transmission electron microscopy (TEM). The droplet size of microemulsions ranged from 70 to 500 nm with average particle size 186 nm. The optimized microemulsion was converted into hydrogel using carbopol 971 which had a viscosity of 498 ± 0.04 cps. During in vitro permeation study the flux of microemulsion formulation and gel was found to be 19.05 and 10.2 µg/cm²/hr, respectively, which indicated better penetration of linseed oil through the skin. These result indicated that the developed ME formulation may be a good approach for topical therapy for the management of psoriasis.     

Leaching Studies of Inorganic and Organic Compounds from Fly Ash

Fly ash is produced in massive quantities by fossil fuel based power plants and waste incinerators, and contains high levels of potentially toxic chemicals. Various leaching tests exist to determine the available fractions, but the outcome is strongly dependent on the experimental conditions, and these have not yet been harmonised at the international level. In order to test existing protocols for heavy metals, several intercomparisons were organised within the framework of an EU-INCO project "ANALEACH", in which seven institutes from five countries participated. Two existing reference materials were made available for the project and test batches of two new fly ash reference materials were produced. Availability tests, leaching tests and pH-stat tests were studied and critical steps in the procedures were identified. Fly ashes can also contain large amounts of inorganic sulphur and nitrogen compounds, and the determination and leaching behaviour of these compounds were also studied. In one intercomparison for metals, inorganic S and N-compounds were also included. A five-step leaching test was optimised for fly ash in order to link metal fractions to different types of binding. Column leaching experiments were carried out to investigate leaching from fly ash into soil, mimicking the effects of (acid) rain on fly ash deposited on topsoil after atmospheric transport. The major fraction of the leached metal ions was retained by the soil. Also large numbers of organic compounds (including many toxic ones) were identified in fly ash extracts, especially in city waste incinerator ash. Leaching procedures based on ultrasonic extraction were developed for organic compounds and an intercomparison exercise was organised. In a field study at the river Nitra(Slovakia) numerous organic pollutants were found at elevated levels downstream from a major fly ash dump site.     

Efficiency of Different Methods and Solvents for the Extraction of Polycyclic Aromatic Hydrocarbons from Soils

The efficiencies of supercritical fluid extraction (SFE), accelerated solvent extraction (ASE), Soxhlet, and ultrasonic extraction in the analysis of polycyclic aromatic hydrocarbons (PAHs) in soils were evaluated. Solvents with different polarity were used to extract the PAHs from two soils, one with high and one with low contamination level. ASE showed good results with all solvents almost independent of the solvent polarity and the best results with acetone-toluene (1 : 1). Ultrasonic extraction with acetone-toluene for the uncontaminated soil and acetone-ethanolamine for the highly contaminated also showed good recoveries. The time-consuming Soxhlet extraction with pentane or dichloromethane was less effective. The PAH recovery from SFE was related to the soil matrix or the contamination level. The best extraction conditions (CO 2 /10% pentane) are successful for the soil with a low contamination level and a high humic acid content whereas the extractions of the highly contaminated soil gave poor results irrespective of the solvent used.     

Bioluminescent Microcapsules: Applications in Activating a Photosensitizer

Bioluminescent microcapsules uploading D ‐luciferin have been fabricated by using the covalent assembly of firefly luciferase and alginate dialdehyde through a layer‐by‐layer technique. Such assembled microcapsules can produce visible light in the region of 520–680 nm, which can activate the photosensitizers rose bengal (RB) and hypocrellin B (HB) after adding ATP. The microcapsules uploading photosensitizers (RB or HB) have an obvious property to prevent the proliferation of tumor cells in the dark. The assembled bioluminescent microcapsules can be potentially used as photon donors for bioimaging, ATP detection, and photodynamic therapy.