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.
Praise be to God, Lord of the worlds, and the best of prayers. He has completed the delivery of our master Muhammad, his family, and all his companions. O God, bring us out from the darkness of illusion, honor us with the light of understanding, open us with knowledge of knowledge, facilitate our morals with dreams, and make us who listen to the saying and follow their best.
And after ..
Since ancient times, magic was mentioned in many books in the history of the civilizations of ancient peoples, where the first emergence of human civilizations, the oldest of which is the Mesopotamian civilization, the Chinese civilization, and the Pharaonic civilization in Egypt, where concepts prevailed based on the charlatans and sorcery an
... Show MoreThis study is concerned with the evaluation of the effect of Euphrates River water quality in Al-Samawa region during
the period 1984-2003 on efficiency and reliability of reverse osmosis desalination systems by calculating the calcium
sulfate scaling index depending on the following indicators: - TDS, Ca+2, Mg+2, Na+1, Cl-1, So4-2, HCO3-1. It was
found from data analysis that this index for these units is greater than permissible limit. Also, the fitted relationship
between this index and TDS is logarithmic, i.e. this index varies more rapidly than TDS, and consequently it is more
representative to the water quality than TDS.
The work include synthesis of nanocomposites (X / S / Ag) based on blend from Xanthan gum / sodium alginate polymers (X / S) with different loading of synthesized silver nanoparticales (0.01, 0.03 and 0.05 wt%) were added to the blend. The silver nanoparticles were prepared by reduction method and were characterized and analyzed using X-ray diffraction (XRD) and Atomic force microscope (AFM). XRD study showed the presence nanoparticle of silver with crystalline nature and face-centered cubic (FCC) structure and an average size of nanoparticles ranging from 32 to 37 nm. The surface study was performed using AFM which showed a fairly uniform shape to the nanocomposites and a spherical nature for the silver nanoparticles. The nanocomposite exh
... Show MoreThis work contain many steps starting from esterification of isophthalic acid to yield diester compound [I] which was converted to their acid hydrazide [II], then the later compound reacted with ethylacetoacetate to yield pyrazol-5-one compound [III]. Afterword added acetyl chloride to give the compound [IV], thereaction of this compound with theiosemicarbazide ledto produce a new carbothioamide compound [V], Which was reacted with ethyl chloro acetate to yield thethioxoimidazolidin compound [VI]. The condensation reaction of this compound with different substituted aldehyde give new alkene derivatives[VII]a-d. The synthesized compounds were characterized by melting points , FT-IR ,1H-NMR and Mass spectroscopy .
As we have said that the reasons for abortion are many and varied them to be for
the purpose of treatment or the protection of the mother of the loss or that the abortion
of an act intended purpose of birth control or other reasons is the statistics that are
spread in the world that about 50-60 million abortions annually in the world If this
abortion criminal who is loss of the lives of fetuses and a disgrace to the preachers to
the progressive and liberal, secular, and because they were not able to maintain
human life after leaving the obligation to approach Islam and because life support is
the highest things, which is one of the necessities of the five obligatory street
maintenance came verses warn those who un
In recent decades, global obesity has increased significantly, causing a major health problem with associated complications and major socioeconomic issues. The central nervous system (CNS), particularly the hypothalamus, regulates food intake through sensing the metabolic signals of peripheral organs and modulating feeding behaviors. The hypothalamus interacts with other brain regions such as the brain stem to perform these vital functions. The gut plays a crucial role in controlling food consumption and energy homeostasis. The gut releases orexigenic and anorexigenic hormones that interact directly with the CNS or indirectly through vagal afferent neurons. Gastrointestinal peptides (GIP) including cholecystokinin, peptide YY, Nesf
... Show MoreThis text and guide discusses the surgical and medical management of congenital heart diseases in both adult and children. It describes the disease, pathology, treatment, complications and follow-up with extensive use of didactic material to educate the reader to the practicalities of the subject. It details the novel research via an extensive literature review, while covering all aspects of the surgical and medical treatment of congenital heart disease. It includes review of the laparoscopic techniques and epidemiology of each disease involved and their prevalence to provide the reader with the full clinical picture. Clinical and Surgical Aspects of Congenital Heart Diseases: Text and Study Guide provides a thorough practical reference fo
... Show MoreActivated carbon loading with metals oxides is new adsorbents and catalyst, which seem very promising for desulfurization process. The present study deals with the preparation of three metals oxides loaded on activated carbon (AC). The tri composite of ZnO/NiO/CoO/AC was characterized by X-Ray Diffraction (XRD), X-Ray florescence (XRF), N2 adsorption for BET surface area, pore volume and Atomic Force Microscopy (AFM). The effect of calcination temperature is investigated. The best calcination temperature is 250oC based on the presence of phase, low weight loss and keep at high surface area. The surface area and pore volume of prepared tri composite are 932.97m2/g and 0.6031cm3/g respec
... Show MoreNovel heterocyclic polyimide 5(a,b) have been synthesized based on polyacrylic backbone. The synthetic route start with nucleophilic substitution of 2-amino, or 4-amino, pyridine 1(a,b) to the polyacryloyl chloride afforded poly substituted amide 2(a,b). Another nucleophilic substitution were carried with adipoyl chloride to form polyimide chloride 3(a,b). Treatment of 3(a,b) with hydrazine hydrate afforded acid hydrazide polyimide 4(a,b), which upon cyclocondensation with carbon disulfide gave the target heterocyclic polyimide. The synthesized compounds were identified by spectroscopic methods: FT-IR, 1H-NMR and 13C-NMR.