Nutritional constituents and antioxidant properties of indigenous kembayau (Dacryodes rostrata (Blume) H. J. Lam) fruits

The nutritional and antioxidant properties of peels, pulp and seeds of kembayau (Dacryodes rostrata) fruits were evaluated. Kembayau seeds and pulp were rich in fat, while peels had the highest ash contents. Potassium was the most prevalent mineral in peels (380.72-1112.00 mg/100 g). In kembayau fruits, total flavonoid content (1012.74-28,022.28 mg rutin equivalent/100 g) was higher than total phenolic and total monomeric anthocyanin contents. Kembayau seeds exhibited high flavonoid and phenolic contents compared to the contents in peels and pulp. Antioxidant capacities were also higher in seeds as typified by trolox equivalent antioxidant capacity assay (51.39-74.59 mmol TE/100 g), ferric reducing antioxidant power assay (530.05-556.98 mmol Fe²⁺/100 g) and by 1,1-diphenyl-2-picryl hydrazyl radical scavenging activity (92.18-92.19%) when compared to peels and pulp. Pulp and peels of kembayau fruit may be an important source of energy and minerals for human consumption, while seeds have a good potential as antioxidants.     

Assessment of in vitro antioxidant, antibacterial and immune activation potentials of aqueous and ethanol extracts of Phyllanthus niruri

BACKGROUND: Recently much attention has been paid to biologically active plants because of their low production cost and fewer adverse effects compared with chemical drugs. In the present investigation the bioactivity of Phyllanthus niruri ethanol and aqueous extracts was evaluated in vitro. RESULTS: The ethanol extract of P. niruri showed a high level of flavonoid content (123.9 ± 0.002 mg g^?1), while the aqueous extract showed the highest 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH; IC₅₀6.85 ± 1.80 µmol L^?1) and 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS; 46.44 ± 0.53 µmol L^?1) free radical scavenging activities with high phenol content (376 ± 0.02 mg g^?1) and elevated levels of ferric reducing antioxidant power (FRAP; 23 883 ± 0.019 mmol g^?1) with excellent antibacterial activity against Staphylococcus aureus (20 mm inhibition zone) and Streptococcus agalactiae (12 mm inhibition zone), respectively, in addition to the best immune activation potential of human peripheral blood mononuclear cells (450.5%). CONCLUSIONS: It is clear from our results that both extracts of P. niruri has excellent bioactivity roles via elevated levels of antibacterial, antioxidant and percentage of peripheral blood mononuclear cell proliferation, which could lead to the development of medications for clinical use. Copyright © 2012 Society of Chemical Industry     

Cathodic electrodeposition of Y(OH)3 and Y2O3 nanostructures from chloride bath. Part II: Effect of the bath temperature on the crystal structure,composition and morphology

Ultra-fine nanoparticles, mono-dispersed nanospheres and nanorods of Y(OH)₃ and Y₂O₃ were successfully prepared via electrodeposition from chloride bath at different temperatures of 10, 25, 40 and 80 °C followed by heat-treatments at 600 °C in dry air atmosphere. Thermal behavior of the hydroxide samples was investigated by differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis. The structural and morphological characteristics of the products were determined by X-ray diffraction (XRD), FT-IR, scanning and transmission electron microscopy (SEM and TEM). Effects of bath temperature on the mechanism of base electrogeneration and deposit formation on the cathode surface were proposed and discussed. The results showed that the crystal structure, composition and morphology of the products are mainly affected by the temperature of electrodeposition bath.     

A convenient solvent-free and one-pot synthesis of 4-hydroxythiazolidine-2-thiones

A highly efficient solvent-free and simple one-pot approach for the synthesis of 4-hydroxythiazolidine-2-thione is described. The reaction of primary amines and carbon disulfide in the presence of 2-chloroacetaldehyde afforded the title compounds in high yields.     

Utilization of aluminum sludge and aluminum slag (dross) for the manufacture of calcium aluminate cement

Four calcium aluminate cement mixes were manufactured from aluminum sludge as a source of calcium oxide and Al₂O₃ and aluminum slag (dross) as a source of aluminum oxide with some additions of pure alumina. The mixes were composed of 35–50% aluminum sludge, 37.50–48.75% aluminum slag (dross) and 12.50–16.25% aluminum oxide. The mixed were processed then sintered at different firing temperatures up to 1500 °C or 1550 °C. The mineralogical compositions of the fired mixes investigated using X-ray diffraction indicated that the fired mixes composed of variable contents of calcium aluminate (CA), calciumdialuminate (CA₂), calciumhexaaluminate (CA₆) in addition to some content of magnesium aluminate spinel (MA). Sintering parameters (bulk density, apparent porosity and linear change) and mechanical properties (cold crushing strength) of the fired briquettes were tested at different firing temperature. Refractoriness of the cement samples manufactured at the optimum firing temperature was detected. Cementing properties (water of consistency, setting time and compressive strength as a function of curing time up to 28 days of hydration) of pasted prepared from the manufactured cement mixes at the selected optimum firing temperatures (1400 °C or 1500 °C) were also tested. Cement mixes manufactured from 45 to 50% aluminum sludge, 37.50–41.25% aluminum slag (dross) with 12.50–13.75% alumina were selected as the optimum mixes for manufacturing calcium aluminate cement since they satisfy the requirements of the international standard specifications regarding cementing and refractory properties as a result of their content of CA (the main hydraulic phase in calcium aluminate cement) and CA₂(the less hydraulic but more refractory phase). Although the recognized high refractoriness of CA₆, its formation affect badly the cementing properties of the other non-optimum mixes.     

Amorphous carbonated apatite formation on diamond-like carbon containing titanium oxide

Thin films of diamond-like carbon (DLC) containing titanium oxide (DLC-TiO_x, x ≤ 2) were synthesized using a pulsed DC metal–organic plasma activated chemical vapor deposition (MOCVD) technique. X-ray photoelectron spectroscopy (XPS) results confirmed the presence of TiO₂ on the surface of the films. The compressive stress, elastic modulus and hardness of the films decreased with increasing Ti content. The water contact angle reduced from 62° for DLC to 45° for DLC-TiO_x films containing 13.3 at.% of Ti. The biomimetic growth of amorphous carbonated apatite on the DLC-TiO_x in simulated body fluid (SBF) was found and dependent on the Ti content of the film. UV light exposure prior to immersion in SBF increased the growth rate of apatite formation significantly as a result of increased hydrophilicity of the surface.     

Geometrically nonlinear bending analysis of Metal-Ceramic composite beams under thermomechanical loading

A new method is developed to derive equilibrium equations of Metal-Ceramic beams based on first order shear deformation plate theory which is named first order shear deformation beam theory2(FSDBT2). Equilibrium equations obtained from conventional method (FSDBT1) is compared with FSDBT2 and the case of cylindrical bending of Metal-Ceramic composite plates for non-linear thermomechanical deformations and various loadings and boundary conditions. These equations are solved by using three different methods (analytical, perturbation technique and finite element solution). The through-thickness variation of the volume fraction of the ceramic phase in a Metal-Ceramic beam is assumed to be given by a power-law type function. The non-linear strain-displacement relations in the von-Kármán sense are used to study the effect of geometric non-linearity. Also, four other representative averaging estimation methods, the linear rule, Mori-Tanaka, Self-Consistent and Wakashima-Tsukamoto schemes, by comparing with the power-law type function are also investigated. Temperature distribution through the thickness of the beams in thermal loadings is obtained by solving the one-dimensional heat transfer equation. Finally it is concluded that for Metal-Ceramic composites, these two theories result in identical static responses. Also the displacement field and equilibrium equations in the case of cylindrical bending of Metal-Ceramic plates are the same as those supposed in FSDBT2.     

Non-Fourier heat conduction in a hollow sphere with periodic surface heat flux

Presented is the analysis of non-Fourier effect in a hollow sphere exposed to a periodic boundary heat flux. The problem is studied by deriving an analytical solution of the hyperbolic heat conduction equation. Using the obtained analytical expression, the temperature profiles at outer and inner surfaces of the sphere are evaluated for various thermal relaxation times. By comparing the results of non-Fourier model with those obtained from Fourier heat conduction equation, the transition process from parabolic model to hyperbolic one is shown. The phase difference and amplitude ratio of boundary surfaces are calculated as functions of the thermal relaxation time and the results are depicted graphically.