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.
Modified unsaturated polyester (MUPE) was blended with Cellulose (Cls) and with ethyl cellulose (ECls) at ambient conditions in the presence of ethyl methyl ketone peroxide (EMKP) as hardener. The blends containing different weight percentages (5-25 %) of Cls or ECls. Mechanical properties (impact strength, hardness, and bending) and dielectric constant were determined. The results observed that Cls increases the impact strength, hardness, and dielectric constant and decreases the bending of the MUPS, while ECls causes an increase in the three mechanical behaviours and a decrease in the dielectric constant of the MU-PS.
The discus throwing event is one of the complex events in athletics, and it is characterized by a performance method that depends on the principle of mechanical moments and requires high explosive capabilities of the thrower in addition to some physical specifications,which depends effectively and effectively on the biomechanical aspects in generating large moments during rotation. The importance of the research is highlighted by the interest in athletics, especially the effectiveness of the discus throw and the continuation of its development process, the importance of kinetic analysis in revealing the most important weaknesses and strengths of shooters, and the importance of explosive power And the moments generated in the rotation of the
... Show MoreFollowing the political development in Iraq Since 7112 exposed kind of political traditions about how to manage the conflicts that have different Iraqi powers .That what was clear since the formation of permanent government since in 7112 .
The case of conflict between political powers in administrating Iraq state and the withdrawal of American Forcesintroduces questions:
0-Is it possible that that the beginning of Iraq state building shall ease this conflict and peacemaking in the post-conflict period?
7- To what extent the Iraqi powerswas to manage their disputes in non-military like elections which was held in 7112?
2- What is the range of the extent of the political operation after the American withdrawal?
The important
This study is concerned with the recent changes that occurred in the last three years (2017-2019) in the marshes region in southern Iraq as a result of the changes in the global climate, the study included all the water bodies in the five governorates that are located in the southern regions of Iraq (Wasit, Maysan, Dhi-Qar, Qadisiyah and Basrah), which represent the marshes lands in Iraq. Scenes of the Landsat 8 satellite are used to create a mosaic to cover the five governorates within a time window with the slightest difference between the date of the scene capture, not to exceed 8 days. The results of calculating the changes in water areas were obtained using the classifier support vector machine, where high accuracy ratios were recorded
... Show MoreBackground: Although the issue of anemia after renal transplantation (RT) has received increasing attention lately, the data on the exact prevalence of post-transplantation anemia (PTA) in the Iraqi patients are limited. Objective: In this study we sought to determine the prevalence of PTA among Iraqi patients and to correlate the renal allograft function measurements and the use of immunosuppressant with the prevalence of anemia. Patients and Methods: One hundred and twelve (74 male, 38 female) kidney transplant recipients (KTR) attending the kidney transplant center at surgical specialties hospital were studied. All patients were on maintenance, combined immunosuppressive therapy. The renal function tests [blood urea, serum cre
... Show MoreThe research seeks to examine the image of women in Iraqi films produced after 2003 over the answer to questions such as “ level of the representation of women and appearing in films and features that are attributable to them and their relationships with men and their interests and tendencies , activities and ways and methods pursued to achieve their goals , or what appeared to be trying to achieve and whether made movies vivid and varied models for women, or confined to a rigid model and duplicate Is films raised issues concerning women? The research seeks to examine the image of women in Iraqi films produced after 2003 over the answer to questions such as “ level of the representation of women and appearing in films and features th
... Show MoreThis research aims to identify the reality of Sino-Russian relations after 2013, and to study the most important motives and determinants that affected the nature of these relations. The research was based on the criterion of national interest in interpreting and understanding relations between China and Russia, on the basis that national interest is what determines the state of cooperation and dependence, or the state of competition and difference. The research was based on the hypothesis that Sino-Russian relations after 2013 witnessed many factors and variables, some of which represented motives for strengthening relations between the two countries, and others represented obstacles that limit the level of cooperation and interaction betw
... Show MoreAbstract: This research deals with the developing of power and different abilities (military, security, economy, technology and scientific excellence) The research shows that the excellence of the Chinese economy and its development , had a positive reflection on the other powers and abilities , it means it is a base of development in all fields. The development in power and Chinese military abilities had a clear effect on Chinese strategic creed , and that what the research deals with in some details. The research also deals with developing Chinese nuclear abilities. The research doesn't ignore the security eye that indicates to the protection of the state sovereignty, concentrating on the unity and safety Chinese lands. The res
... Show Moreيمر العالم و المنطقة العربية وضعاً استثنائياً في ظل انتشار فايروس كورونا - 19 - المستحد وما تبعها من تداعيات على جميع الاصعدة في ظل تأثير تلك الجائحة وعلى شتى الاصعدة والمجالات كونها متداخلة ومترابطة معاً، ولاسيما القطاع الاقتصادي المهم الذي ينعكس بصورة مباشرة على المجالات الأخرى، لكون هذا الجانب الاساس الذي يميز المنطقة العربية فهي منطقة غنية بالموارد الطبيعية كالنفط و الغاز الطبيعي، فضلا عن الموقع الاسترا
... Show More