Background: Radiopacity is one of the prerequisites for dental materials, especially for composite restorations. It's essential for easy detection of secondary dental caries as well as observation of the radiographic interface between the materials and tooth structure. The aim of this study to assess the difference in radiopacity of different resin composites using a digital x-ray system. Materials and methods: Ten specimens (6mm diameter and 1mm thickness) of three types of composite resins (Evetric, Estelite Sigma Quick,and G-aenial) were fabricated using Teflon mold. The radiopacity was assessed using dental radiography equipment in combination with a phosphor plate digital system and a grey scale value aluminum step wedge with thickness varying from 1mm to 10mm in steps of 1mm each. The tested materials were radiographed, we used Image J software, on a computer screen to evaluate the degree of radiopacity for each individual material and compare with the aluminum step wedge. Radiopacity was expressed in mm of equivalent aluminum step wedge. Analysis of varience (ANOVA) and Least Significant Difference (LSD) were used to investigate the significance of differences among the tested groups. Results: Statistical analysis showed highly significant difference among the tested groups (p≤0.01). Amongst, G-aenial composite shows the most radiopaque and it is above or equivalent to that of enamel, while Estelite Sigma Quick composite has the lowest radiopacity value and is equivalent to that of dentin. Conclusion: In line with previous studies, and within the limitation of our study, considerable variations in radiopacity values were found among materials depending on the radiopaque elements incorporated into the matrix. All composite materials tested complied with the ISO 4049 standard.
Essential approaches involving photons are among the most common uses of parallel optical computation due to their recent invention, ease of production, and low cost. As a result, most researchers have concentrated their efforts on it. The Basic Arithmetic Unit BAU is built using a three-step approach that uses optical gates with three states to configure the circuitry for addition, subtraction, and multiplication. This is a new optical computing method based on the usage of a radix of (2): a binary number with a signed-digit (BSD) system that includes the numbers -1, 0, and 1. Light with horizontal polarization (LHP) (↔), light with no intensity (LNI) (⥀), and light with vertical polarization (LVP) (↨) is represen
... Show MoreEmotional blackmail is generally defined as manipulating others' emotions for personal gain. It is a type of manipulation that damages healthy relationships among people and turns them into toxic relations leaving the victim in a state of depression and under stress of losing something s/he holds dear. This study aims to identify the pragmatic techniques of emotional blackmail used by both blackmailers and victims in "No One Would Tell" (2018). To do so, the researchers developed an eclectic model comprising Forward and Frazier's (1997) emotional blackmail, Searle’s speech acts (1979), Brown and Levinson’s politeness strategies (1987), Culpeper’s impoliteness strategies (1996, 2005), and Mayfield's taxonomy of fallacy (2007)
... Show MoreIn his post colonial novel, In the Skin of a lion, the Canadian/Sri Lankan writer,
Michael Ondaatje is so interested in the term "Post colonialism" because he wants to show
that the term doesn't only refer to a period of time that comes after colonialism. In other
words, post colonialism is not only referred to as a literal description of formerly colonial
societies. He deals with the termas a literary genre and an academic construct that describes
the global conditions of a man after a period of colonialism. He shows that post colonialism is
a theory that tries to examine and explore the different styles and faces of European authority
to control the colonized. Ondaatje's attempt through such term is to unmask Europ
The present paper investigates the role of fear and predator dependent refuge in the prey-predator system. The system describes the interaction between prey and a stage structure of predator that incorporates Holling II functional response. The predator splits into two compartments immature (juvenile) and mature (adult). The mature predators can hunt and reproduce but this capability is not found in the immature predators, the immature depend on their parents. The growth rate of prey decreases due to the existence of mature predators. The existence, uniqueness, and boundedness of the solution of the system are investigated. Three equilibrium points of the system are determined. The local stability of the system is studied. The global stabil
... Show MoreThis work presents a computer studying to simulate the charging process of a dust grain immersed in plasma with negative ions. The study based on the discrete charging model. The model was developed to take into account the effect of negative ions on charging process of dust grain.
The model was translated to a numerical calculation by using computer programs. The program of model has been written with FORTRAN programming language to calculate the charging process for a dust particle in plasma with negative ion, the time distribution of a dust charge, number charge equilibrium and charging time for different value of ηe (ratio of number density of electron to number density of positive ion).
An inert matrix that is used to control the release of (PTX) was prepared using Eudragit RL100 and RSPM types as matrix forming agent . The matrices were prepared by either dry granulation(slugging) , or wet granulation method using chloroform as a solvent evaporation vehichle. The cumulative release was adjusted by using polyvinylpyrollidone (PVP) or ethylcellulose (EC) polymers .The results indicated that both methods of preparation were valid for incorporation PTX as a sustained release granules .Moreover ,the results revealed that best polymer used was Eudragit RSPM in 3:20 polymer drug ratio .Besides to that , the results indicated that the release profiles were affected by pH- medium&
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