Design optimisation of additively manufactured titanium lattice structures for biomedical implants

A key advantage of additive manufacturing (AM) is that it allows the fabrication of lattice structures for customised biomedical implants with high performance. This paper presents the use of statistical approaches in design optimisation of additively manufactured titanium lattice structures for biomedical implants. Design of experiments using response surface and analysis of variance were carried out to study the effect design parameters on the properties of the AM lattice structures such as ultimate compression strength, specific compressive strength, elastic modulus, and porosity. In addition, the lattice dimensions were optimized to fabricate a diamond cellular structure with properties that match human bones. The study found that the length of a diamond-shaped unit cell strut is the most significant design parameter. In particular, the porosity of the unit cell increases as the strut length increases, while it had a significant reverse effect on the specific compressive strength, elastic modulus and ultimate compression strength. On the other hands, increasing the orientation angle was found to reduce both the specific compressive strength and modulus of elasticity of the lattice structure. An optimised lattice structure with strut diameter of 0.84 mm, length of 3.29 mm and orientation angle of 47° was shown to have specific compressive strength, elastic modulus, ultimate compression strength and porosity of 37.8 kN.m/kg, 1 GPa, 49.5 MPa and 85.7%, respectively. A cellular structure with the obtained properties could be effectively applied for trabecular bones replacement surgeries

IR, 1H-NMR, UV-Vis and thermal studies on the Rhodamine 6G charge-transfer complexes

Charge-transfer (CT) complexes formed between Rhodamine 6G (Rh6G) as donor with iodine, CLA and PA as acceptors have been studied spectrophotometrically. The synthesis and characterization of Rhodamine 6G CT-complexes of iodine, [(Rh6G)2]I+.I3ˉ, chloranilic acid (CLA), [(Rh6G)(CLA)] and picric acid (PA) [(Rh6G)(PA)] were described. These complexes are readily prepared from the reaction of Rh6G with I2, CLA and PA with CHCl3 solvent. Mid and far IR, 1H-NMR, UV-Vis techniques, elemental analyses (CHN) and thermal studies, characterize the three new Rhodamine 6G charge-transfer complexes. Modified Benesi-Hildebrand method was applied to the determination of association constant and molar extinction coefficient.KEY WORDS: Rhodamine 6G, Charge transfer complexes, Picric acid, Chloranilic acid, Iodine, Thermal studies Bull. Chem. Soc. Ethiop. 2011, 25(1), 137-146

On the solvability of a nonlinear functional integral equations via measure of noncompactness in

Using the technique of a suitable measure of non-compactness and the Darbo fixed point theorem, we investigate the existence of a nonlinear functional integral equation of Urysohn type in the space of Lebesgue integrable functions Lp(RN). In this space, we show that our functional-integral equation has at least one solution. Finally, an example is also discussed to indicate the natural realizations of our abstract result

Evaluation of some functionalized imidazoles and 1,2,4-triazoles as antioxidant additives for industrial lubricating oils and correlating the results with the structures of additives using empirical AM1 calculations

AbstractFunctionalized 4,5-diphenyl-imidazoles, 4,5-diphenyl-1,2,4-triazoles and 5-(o-hydroxyphenyl)-4-phenyl-1,2,4-triazoles at the 2-position with thiol, thiomethyl and thiobenzyl groups, have been tested as antioxidant additives for lubricating oils. Whereas the thiomethyl groups in such compounds increased the antioxidant property than the thiol group, the corresponding thiobenzyl groups did the reverse. The results can be explained, based on correlating the electron donating and withdrawing abilities of the substituents with the oxidation stability. The triazoles carrying a phenolic hydroxyl group have more antioxidant power than those without such a group. The imidazoles gave the oils more oxidation stabilities than the two types of triazoles with the same functionalities. The 4,5-diphenyl-2-thiomethyl-imidazole (2), as an additive, has the highest antioxidant property, reaching the level of standard one when its concentration is 1.0% wt. instead of the 0.8% wt. of the standard. The correlation of the antioxidant character of the heterocyclic additives with their structures has been investigated using the semiempirical gas phase AM1 calculations for the studied heterocycles. The relative stability of the imidazoles 1 and 3 compared to 2 were in the order 2>1>3. Similarly, the relative stability of the triazoles are in the same order where 5>4>6 and 8>7>9

EVALUATION OF GROUNDWATER QUALITY OF SIWA OASIS

In discussing the water quality evaluation for use in different purposes, the author will briefly examine some of the major important water quality standards. These standards serve as a basis for appraisal of the results of chemical water analysis in terms of suitability of the water for various intended uses. According to total dissolved salts (TDS),  major  ions as cations ( Ca2+, Mg2+, Na+, K+), anions (CO₃2â», HCO₃â»Â  ,SOâ‚„2â», Clâ»), with some heavy metals such as Al3+, B3+ , Cd2+, Co2+, Cr3+, Cu2+, Fe3+, Mn2+,  Mo2+, Ni2+,  Pb2+, Sr2+, V2+   and Zn2+  The results  indicate  that  the samples of Nubian sandstone aquifer is suitable for drinking of human and livestock , suitable for laundry purposes and for irrigation. While the samples of Fractured dolomite limestone aquifer are unsuitable for drinking and irrigation.Â

Effect of Addition Antioxidants to Beef Meatballs on Oil Oxidative Stability during Deep Fat Frying

This study was aimed to investigate the effect addition of antioxidants to meatballs formulation on frying oil oxidative stability during deep fat frying. 200 ppm butylated hydroxytoluene (BHT), 2500 ppm rosemary extract (ROS) and 500 ppm ascorbic acid (ASC) were added separately to palm olein to achieve the study. The results showed that the addition of antioxidants to meatballs reduce the increment in refractive index during frying process as compared to control, while the rosemary extract was have the lowest refractive index among the antioxidant containing treatments. In regard to relative viscosity the addition of antioxidants to meatballs results in lower relative viscosity values as compared to control treatment. Since, rosemary extract was exhibited superior ability in reducing the formulation of free fatty acids which increased during the frying process in all treatments with low rates for antioxidant containing treatments. In regard to peroxide value, rosemary extract has been kept peroxide value under the ESS limit for long period (120 min.) followed by BHT containing treatment (90 min.), while ascorbic acid was similar to control in keeping peroxide value under the Codex Stand (No. 210/1999) and ESS (1706/2005) limit (60 min.). Changes in TBA value were observed during the progressing in frying process, the rate of increasing TBA value was low in antioxidant containing treatments as compared to control, also rosemary extract showed the lowest TBA values among all treatments along the frying period. Polymerization of oil ? during the frying process was reduced by addition of antioxidants to meatballs as compared to control, while the lowest polymerization percent was observed in rosemary extract treatment. The results of iodine value exhibited decreasing in iodine value as the frying time increased. Finally the rosemary extract was exhibit superior ability in protection the oil from oxidation during frying process

Perfil lipídico, compuestos volátiles y estabilidad oxidativa durante el almacenamiento del aceite de semilla de Opuntia ficus-indica marroquí

The fatty acids, sterol, tocopherol and volatile compositions of Moroccan cold-pressed cactus (Opuntia ficus-indica) seed oil were studied. The most abundant fatty acid, tocopherol and sterol were linoleic acid (60.6%), γ-tocopherol (533 mg/kg) and β-sitosterol (6075 mg/kg), respectively. In this study, 23 volatile compounds were identified with perceivable odor attributes for 14 compounds. The oxidative quality of cactus seed oil was monitored over 4 weeks at 50 °C. Increases in PV, K232 and FFA were detected during the first two weeks as well as a decrease in the induction time; whereas no change was reported for the K270 values. The amount of total phenolic content increased until it reached 0.3 mg/kg and then decreased by the end of the storage period; while tocopherols started to decrease after the first week. The fat-free residue extracts showed a very strong effect to reduce the oxidation of linoleic acid. Consequently, the extracts were significantly more effective to bleach β-carotene in the β-carotene-linoleic acid assay in comparison with the control.Se estudiaron los ácidos grasos, esteroles, tocoferoles y la composición volátil del aceite de semilla de cactus marroquí (Opuntia ficus-indica) prensado en frío. Los ácidos grasos, tocoferoles y esteroles más abundantes fueron el ácido linoleico (60,6%), γ-tocoferol (533 mg/kg) y β-sitosterol (6075 mg/kg), respectivamente. En este estudio, se identificaron 23 compuestos volátiles con atributos perceptibles para 14 de ellos. La oxidación del aceite de semilla de cactus fue monitoreada durante 4 semanas a 50°C. Se observó un aumento en el PV, K232 y FFA durante las dos primeras semanas y una disminución en el tiempo de inducción, mientras que no se apreciaron cambios para los valores de K270. La cantidad de fenoles totales aumentó hasta alcanzar 0,3 mg/kg y luego disminuyó al final del almacenamiento, mientras que los tocoferoles comenzaron a disminuir después de la primera semana. Los extractos de residuos libres de grasa mostraron un efecto muy fuerte para reducir la oxidación del ácido linoleico. En consecuencia, los extractos fueron significativamente más efectivos para blanquear el β-caroteno en el ensayo de β-caroteno-ácido linoleico en comparación con el control

Partial dietary fish meal replacement with cotton seed meal and supplementation with exogenous protease alters growth, feed performance, hematological indices and associated gene expression markers (GH, IGF-I) for Nile tilapia, Oreochromis niloticus

A 12-week feeding trial was conducted to evaluate the effect of different ratios of fish meal (FM): cotton seed meal (CSM) without or with inclusion of exogenous protease in diets on growth performance, hematology, digestibility and selected gene expression markers (GH and I (IGF-I) of juvenile Nile tilapia. The experimental diets were categorized into three groups; the first group CSM1 which contained fish meal protein: cotton seed meal protein (FM: CSM = 2:1), the second group CSM2 which contained FM: CSM = 1:1 and the third one CSM3 contained FM: CSM = 1:2 on protein content based. All groups were supplemented with exogenous protease at 0 and 2500 U kg−1 diet, respectively. All diets were fed to fish (initial body weight 11.62 ± 0.03 g fish−1) in triplicate aquaria twice daily. The higher weight gain (WG), protein efficiency ratio (PER) and best feed conversion ratio (FCR) were recorded by fish fed CSM1 and CSM2 and supplemented with 2500 U protease/kg diet. The highest apparent digestibility coefficient of crude protein, crude lipid and digestible energy, and apparent availability coefficient of essential amino acids were obtained by fish receiving CSM1 and CSM2 supplemented with protease (2500 U protease kg−1 diet). The highest mean values of Hb, Htc and RBCs were recorded in fish fed CSM1 and CSM2 supplemented with protease enzyme (2500 U protease kg−1 diet). Serum of alanine and aspartate aminotransferase activities were improved due to dietary protease (2500 U protease kg−1 diet) supplementation, also, fish received the diets supplemented with protease 2500 U kg−1 diet generally had higher total protein, albumin, calcium and phosphorus than those fed diets without supplement. The highest growth hormone (GH) gene expression in brain and liver of tilapia were obtained in the group fed CSM3 and un-supplemented with protease enzyme followed by CSM2 (un-supplemented). On the other hand, tilapia fed CSM1 and CSM2 supplemented with protease enzyme showed the highest values of gene expression of insulin like growth factor I (IGF-I) in brain and liver of tilapia compared to other groups. Results above showed that supplementation of protease can improve growth, nutrient assimilation, and hematology and alter gene expression of GH and IGF-I of Nile tilapia

Nanophotothermolysis of Poly-(vinyl) Alcohol Capped Silver Particles

Laser-induced thermal fusion and fragmentation of poly-(vinyl) alcohol (PVA)-capped silver nanoparticles in aqueous medium have been reported. PVA-capped silver nanoparticles with an average size of 15 nm were prepared by chemical reduction technique. The laser-induced photo-fragmentation of these particles has been monitored by UV-visible spectroscopy and transmission electron microscopy. The morphological changes induced by thermal and photochemical effects were found to influence the optical properties of these nanoparticles