Resilient polymeric materials such as silicone elastomers are currently used for maxillofacial prostheses construction but the strength of these materials and their clinical performance need to be optimized with the addition of reinforcing fillers. This study investigates the effect of zirconia nanopowder addition on tear strength, tensile strength, elongation at break, Shore A hardness, surface roughness and cytotoxicity of VST-50 maxillofacial silicone. Silicone base was mixed with different amounts (1%, 2% and 3%) of zirconia nanopowder using a vacuum mixer. Silicone without filler was used as control for comparison. Scanning Electron Microscopy and Atomic Force Microscopy were utilized to assess the efficiency of high-shear vacuum mixing as filler dispersion method and the surface topography, respectively. Both SEM and AFM images showed that the zirconia nanopowder were distributed fairly well within the polymer. Statistically, highly significant increase in tear strength, tensile strength and hardness with non-significant decrease in elongation at break and non-significant increase in surface roughness were seen with 1% and 2% groups. Whereas with 3% group, there was significant improvement in tear strength, tensile strength and hardness but there was significant undesirable decrease in elongation and increase in roughness. Cytotoxicity test revealed that the addition of zirconia nanopowder was nontoxic to Rat Embryonic Fibroblast (REF) cells and there was non-significant change in the cell viability of all study groups after 24- and 72-hours incubation periods. In conclusion, the addition of 2% by weight nano zirconia to VST-50 maxillofacial silicone could be beneficial in enhancing its performance.
Abstract
The study presents a mathematical model with a disaggregating approach to the problem of production planning of a fida Company; which belongs to the ministry of Industry. The study considers disaggregating the entire production into 3 productive families of (hydraulic cylinders, Aldblatt (dampers), connections hydraulics with each holds similar characteristics in terms of the installation cost, production time and stock cost. The Consequences are an ultimate use of the available production capacity as well as meeting the requirements of these families at a minimal cost using linear programming. Moreover, the study considers developing a Master production schedule that drives detailed material and production requi
... Show MoreThe study aimed to identify the effect of the ethical perception of a sample of managers in public organizations on responsible behavior in light of the rapid changes taking place in the external environment. To achieve this, the researcher followed the descriptive analytical approach by applying a questionnaire of two parts. The first part dealt with the ethical perception according to the scale of Johnson (2015), which consisted of (22) items. The second part dealt with measuring responsible behavior, which consisted of (20) items based on the scale of Development of Ethical Behavior (Narvaez, 2006) for a sample of (125) respondents randomly chosen. The results showed that the estimation degree of managers in public governmental o
... Show MoreThe fatty acids in the embryo's liver at ages (7, 11, 14 and 19) days incubation, small chicken aged (14) days after hatching and adult were analyzed, and found (5) fatty acids, the highest concentration of fatty acid in the adult of domesticated chicken and lowest concentration in small chicken age (14) days after hatching. Statistically, there were high significant differences at the probability level (P≤0.001) between all ages together, and the highest concentrations of Oleic acid (C18:1) and Linoleic acid (C18:2) were in embryo age (7) days incubation, while in embryo age (11) days incubation Stearic acid (C18:0) and α-Linolenic acid (C18:3) were higher concentration and Palmitic acid (C16:0) was the highest concentration in the adul
... Show MoreThis study is taken from the doctoral thesis that I prepared in the year 2000 at the University of Bordeaux in France under the title “ Ali bin Abi Talib Imam and Calif “. This thesis was prepared as a continuation of what the French orientalism Louis Massignon wrote about Islam and his student Henry Corbin, who introduced Europeans to Shiism. This study represents the philosophy of dialogue and the unity of the Islamic Emma as one of the most important methods used by Imam Ali.
Imam Ali established the most beautiful, creative, and most complete rules of human dialogue that preserve the unity of the nation’s fabric and preserves human dignity. Imam Ali referred to basic principles foundations to reach this goals, including
... Show MoreThe effect of gamma rays on males and females ofCallasobruchus maculatus and Trogoderma granarium which were irradiated as 1-3 days old adults was investigated. The results revealed that the percent egg hatch for both pests was zero ,and average number of egg (34.2,21.5) for both pests respectively where their males where irradiated with 0.18 kGy and mated with unirradiated females. While the percent of egg hatch and the average number of egg (zero,21,3) respectively when the females where irradiated with 0.18 and 0.15 kGy and mated to unirradiated males for C. maculatus and T. granarium respectively. Furthermore, the results showed that the percent of eggs hatch and average number of egg was ( zero,22.7) for C. maculatus when both sexes i
... Show MoreThe research work involve preparation of activated carbon from Plant corn grain dry in the presence of some additive Residual of poly ethelenetereaphthalate.and the anather way Carbonization was conducted by mixing a known weight of the feedstock with variable quantity of the additive and fixed ratio of Potassium hydroxide. Carbonization completed using fusion in solid state in the absence of solvents. Feedstock and mainly Remnants of poly ethelenetereaphthalate were decompose thermally in a Small chains containing to naphthoxide radicals, these radicals can be connected with the Chains of activated carbon aiming to increase polarity ,This was found from the reaction it self . this research has been studying the product sample was eva
... Show MoreThe aim of this research is to identify how to employ the social imagination and its representations in the paintings of the students of the Department of Art Education. Students of the Department of Art Education in the light of this tool, and the researcher reached a number of results, the most important of which are:
1. The indicator of the social imagination in the excitement of the artist and the recipient, because the representations are embodied in forms within the painting and close to reality.
2. An artistic sample of the representational imagination and the creative imagination was found to be more than the imaginary imagination.
3. Individual symptoms related to the term.
4. The representations of the socia
A study was carried out to determine the concentrations of trace metals in vegetables and fruits, which are locally available in the markets of Baghdad-samples of fourteen varieties of vegetables and fruits, belonging to Beta vulgaris, Brassica rapa, Daucus carota, Allium cepa, Eurica sativa, Malva silvestris, Coriandrum Sativum, Trigonella Foenum craecum, Anethum graveolens, Barassica oleracea, Phaseolus vulgaris, citrus reticulata, Py rus malus, and Punica granatum. Analysis for Cd,Pb, Mn, Fe, Co, Ni, Cu and Zn were determined by flame atomic absorption sp ectrophotometry. The results indicated that the Malva silvestris recorded the highest concentrations of Cd and Mn while Allium cepa showed the highest concentrations of Pb and Cu. But E
... Show MoreAlthough rare, coarctation of aorta is a treatable cause of hypertension, transcatheter dilatation by balloon with or without stent are a well-known treatment strategy