Substrate temperature effect on the photophysical and microstructural properties of fluorine-doped tin oxide nanoparticles

Transparent conducting oxide of fluorine-doped tin oxide (FTO) thin films was deposited from chemical solutions of tin chloride and ammonium fluoride using streaming process for electroless and electrochemical deposition (SPEED) at substrate temperature 450, 500, and 530 ℃ respectively. The effect of substrate temperatures on the microstructural properties such as crystallite size, dislocation density, micro strain, volume of the unit cell, volume of the nanoparticles, number of the unit cell, bond length and the lattice constants were examined using XRD technique. Only reflections from (110) and (200) planes of tetragonal SnO₂ crystal structure were obvious. The peaks are relatively weak indicating that the deposited materials constitute grains in the nano dimension. Hall measurements, which were done using van der Pauw technique, showed that the FTO films are n-type semiconductors. The most favorable electrical values were achieved for the film grown at 530 ℃ with low resistivity of 7.64×10^-4Ω·cm and Hall mobility of -9.92 cm²/(V·s).     

Synthesis of organic derived hydroxyapatite scaffold from pig bone waste for tissue engineering applications

Micro porous hydroxyapatite (HAp) had drawn great attention in the field of tissue engineering due to its numerous applications such as tissue regeneration, dental, drug delivery, and adsorption and desorption of substances etc. The chemical synthesis of HAp is often faced with the high cost of starting materials and often lacks the presence of beneficial ions which can promote biological reactions. This paper examined a novel application of pig bone waste for the synthesis of HAp via heat treatment between 600 and 1000 °C. Thus synthesized powder was characterized by X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FT-IR), Thermogravimetric analysis (TGA), Scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDX) and Transmission electron microscopy (TEM). XRD results revealed the main characteristic peaks of single phase HAp powder, while the presence of various functional groups such as PO₄^3?, CO₃^2? and OH^? corresponding to HAp were observed by FT-IR analysis. The elemental composition of as-synthesized HAp powder as observed by EDX showed the presence of Ca and P in addition to some beneficial metals such as Na, K, Mg and Si which plays vital roles in biological applications. SEM and TEM observation confirmed the microscopic sctructure of the as-synthesized HAp to be rod-like morphology with 38–52 nm in length. Porous HAp scaffold up to 65% porosity could be prepared using ammonium bicarbonate as pore forming agent. Therefore, bio-waste such as pig bones can be utilized in the synthesis of porous hydroxyapatite scaffold which can serve as an alternative for the conventional chemical method.     

Malonaldehyde content of indigenous and imported foods and foodstuffs in Nigeria

Several types of imported and locally available foods and foodstuffs in Nigeria were analysed for their malonaldehyde concentrations. The malonaldehyde levels of imported canned fish products ranged from 0·32 to 3·32 mg/kg. Thermal treatment of mackerel (Scomber scombus) reduced its malonaldehyde level but increased the oncogenic substance of other fish samples. Freezing beef for 4 days increased the malonaldehyde level with a mean of 0·48 mg/kg. The extract from boiled liver had a higher malonaldehyde level than that from raw liver. Milk and milk products did not contain any detectable quantity of malonaldehyde. The need to determine the cumulative effect(s) of ingesting small quantities of malonaldehyde for long periods and further appraisal of all food items for this oncogene are discussed.     

Thermal stability ofThevetia peruviana juss seed oil

Thevetia peruviana seed showed characteristic changes in physicochemical properties when heated at 180, 200, and 220°C over a period of 15 h. There is no striking significant difference in the five parameters (iodine value, acid value, peroxide value, saponification value, and polar compounds) studied for the three working temperatures. Thevetia seed oil showed good thermal stability and will be a good frying and cooking oil.     

Utilisation of transparent synthetic soil surrogates in geotechnical physical models: A review

Efforts to obtain non-intrusive measurement of deformations and spatial flow within soil mass prior to the advent of transparent soils have perceptible limitations. The transparent soil is a two-phase medium composed of both the synthetic aggregate and fluid components of identical refractive indices aiming at attaining transparency of the resulting soil. The transparency facilitates real life visualisation of soil continuum in physical models. When applied in conjunction with advanced photogrammetry and image processing techniques, transparent soils enable the quantification of the spatial deformation, displacement and multi-phase flow in physical model tests. Transparent synthetic soils have been successfully employed in geotechnical model tests as soil surrogates based on the testing results of their geotechnical properties which replicate those of natural soils. This paper presents a review on transparent synthetic soils and their numerous applications in geotechnical physical models. The properties of the aggregate materials are outlined and the features of the various transparent clays and sands available in the literature are described. The merits of transparent soil are highlighted and the need to amplify its application in geotechnical physical model researches is emphasised. This paper will serve as a concise compendium on the subject of transparent soils for future researchers in this field.     

Zinc-doped CdS nanoparticles synthesized by microwave-assisted deposition

Cd_1-xZn_xS nanoparticles were grown on pre-cleaned glass substrates using microwave-assisted chemical bath deposition technique. Nanoparticles obtained by this method were smooth, uniform, good adherent, brownish yellow in color where the brightness of the yellow color nature decreases with increasing Zn²⁺ content. The elemental composition analysis confirmed that the nanoparticles comprise of Cd²⁺, Zn²⁺and S^2-. Scanning electron microscope images confirmed the surface uniformity of the Cd_1-xZn_xS nanoparticles devoid of any void, pinhole or cracks and covered the substrate well. The particle size also decreases with increasing Zn ion content. X-ray diffraction (XRD) indicates the hexagonal structure (002) without phase transition. The grain size decreases from 36.45 to 9.60 nm, dislocation density increases from 0.000745 to 0.01085 Line²/m² and lattice parameter decreased from 6.868 to 6.155 nm with increasing Zn²⁺ content. The best transmittance of about 95% was achieved for x=1.0. The nanoparticles showed reduction in the absorbance as Zn ion content increased. Four point probe revealed that the electrical resistivity increased from 1.51×10¹⁰ to 6.67×10¹⁰ Ω ·cm while electrical conductivity decreases from 6.62×10^-11 to 1.49×10^-11 (Ω ·cm)^-1 with increasing Zn²⁺ content. The other electrical properties such as sheet resistance increased from 1.52×10⁸ to 1.58×10⁸Ω, charge carrier mobility decreased from 0.777 to 0.0105 cm²/(V·s) and charge carrier density increased from 1.06×10¹² to 3.95×10¹² cm^-3.     

Chemical Composition and Antioxidant Activity of Seeds of Various Halophytic Grasses

Increasing population has resulted in overexploitation of conventional seeds. The limited supply of water and salinization of agricultural lands are threats to crop production. This creates food insecurity and results in ever‐increasing prices of crops and edible oils. Halophytes that produce high‐quality seeds can serve as sources of oil and edible products. We analyzed the chemical composition and antioxidant activity of seeds from 5 halophytic grasses, i.e., Aeluropus lagopoides, Eragrostis ciliaris, Eragrostis pilosa, Panicum antidotale, and Sporobolus ioclados. These seeds contained crude protein (10–29%), carbohydrates (32–55%), crude fiber (4–21%), minerals (3.8–9.2%), and oil (4–11%), indicating their nutritional potential. Oils of these seeds had suitable fatty‐acid composition with 62–82% unsaturation and only 17–24% saturation. Out of this, 91–94% of the total oil constituted by linoleic, oleic, and palmitic acids. High contents of total phenols (2.8–4.2 mg gallic acid equivalent [GAE] g^?1), flavonoids (0.5–1.3 mg Quercetin equivalent [QE] g^?1), and tannins (0.3–1.3 mg catechin equivalent [CE] g^?1) supported their high antioxidant activity (1,1‐Diphenyl‐2‐picryl‐hydrazyl (DPPH) activity in terms of half maximal inhibitory concentration‐IC₅₀ 1.1–5.86 mg mL^?1; 2,2′‐azino‐bis3‐ethylbenzothiazoline‐6‐sulphonic acid (ABTS) 18.8–72.8 mmol Trolox g^?1; ferric‐reducing antioxidant power 2.0–4.4 mmol Fe⁺² g^?1). The reverse phase‐high‐pressure liquid chromatography analysis identified the presence of bioactive phenolic antioxidants (mainly gallic acid, chlorogenic acid, coumaric acid, ferulic acid, kaempferol, and quercetin). Due to these characteristic composition and salt tolerability, these plants can serve as potential sources of industrial raw materials for food, edible oil, phytochemicals, and oliochemicals.