Background: Thermocycling simulates the temperature dynamics in the oral environment. This in vitro study done to measure and compare the effect of thermocycling on the shear bond strength of stainless steel and sapphire brackets bonded to human enamel teeth using light cured orthodontic adhesive and debonded at various time, and to measure adhesive remnant index after debonding. Materials and Methods: one-hundred-twenty extracted upper first premolars for orthodontic reason were used in this study; depending on weather thermocycled or not, the sample was divided into two main groups, then within each group 30 teeth were used for stainless-steel brackets (Bionic®) and for sapphire brackets (Pure®). Both groups were subdivided into three groups (n = 10) according to the debond times: I: debond after 24 hour, II: debond after 7 days and III: debond after 30 days. Within 24 hr, half of the sample was thermocycled manually for 500 complete cycles between 5/55°C and the remaining sample was stored in distilled water at room temperature and water was changed daily until debond time for each group was performed. The adhesive remnant index was tested under 20X magnification lens using stereomicroscope. Results and Conclusions: Both bracket types demonstrated high shear bond strength values before thermocycling (P?0.05), whereas after 500 thermocycles, there were significant changes in shear bond strength resulted in marked reduction in the stainless steel brackets than in the sapphire brackets (P?0.05). Shear bond strength values increased with time for both stainless steel and sapphire brackets with and without thermocycling (P?0.05). The tendency of bond failure was increased at the bracket/adhesive interface rather than enamel/bracket interface in the stainless steel brackets whereas at the enamel/bracket interface rather than bracket/adhesive interface in the sapphire brackets.
In this paper the centralizing and commuting concerning skew left -derivations and skew left -derivations associated with antiautomorphism on prime and semiprime rings were studied and the commutativity of Lie ideal under certain conditions were proved.
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Let be a ring. Given two positive integers and , an module is said to be -presented, if there is an exact sequence of -modules with is -generated. A submodule of a right -module is said to be -pure in , if for every -Presented left -module the canonical map is a monomorphism. An -module has the -pure intersection property if the intersection of any two -pure submodules is again -pure. In this paper we give some characterizations, theorems and properties of modules with the -pure intersection property.
The study aimed to describe the anatomical, histological, and histochemical structure of the proventriculuc of adult male Eurasian marsh harrier, Circus aeruginosus (Linnaeus, 1766) (Accipitriformes, Accipitridae). Six birds were used for this study. The histological sections of proventriculus were stained with hematoxylin and eosin, periodic acid Schiff, and alcain blue. The proventriculus, representing the upper stomach, appeared as a conical structure with a thick wall connecting the caudal end of the thoracic esophagus to the gizzard. It had a light brown color. Microscopic examination revealed that the proventriculus wall consists of the outer tunica serosa, the tunica muscularis, tunica sub mucosa, and the inner tunica mucosa.
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The polymeric complexes were obtained from the reaction of polymeric Schiff base.N-crotonyl-2-hydroxyphenylazomethine (HL), with divalent metals Pt (II), Cr (II). The modes of bonding and overall geometry of the complexes were determine through spectroscopic methods and compared with that reported from analogous monomeric ligand. This study revealed square planer geometry around the metal center for [Pt(L)Cl] and distorted octahedral geometry for Cr complex [Cr(L)Cl(H2O)2].
The platforms of social networking sites, with their distinctive communication and technological features, create a social movement that led to the establishment of a new pattern of communication in a modern context. This allows the users on the internet to carry out many social interactions based on the interests and commonalities among them. Algerian women have a share of this digital presence by representing their views and discussing their issues on several sites like Facebook, for example.
In this research, we have analyzed the pages of Algerian women on Facebook site to find out the most important issues addressed by Algerian women so that we can organize their concerns in the digital channels and discover their different orie
This study examines Agence France Presse’s (AFP) media treatment of the Great Return Marches in order to identify its contents, the issues it gave attention to, its sources, attitude, techniques, objectives, the journalistic forms used in covering events and the typographic elements used to highlight them.
This descriptive study employed the survey methodology through the use of content analysis method, and the methodology of mutual relations through the use of the case study method. The data was collected by means of a content analysis form. The study was based on the Agenda Setting Theory in the analysis of the study results.
The study sample included (116) news texts from AFP collected during the period from 20/3/2018 to
Objectives: The study aimed to clarify the role of Al-Sayyid Al-Ajall and his family in the service of the Mongol Empire. They worked to develop its administrative and military institutions, benefiting from their extensive experience in administration, politics, economics, and urban affairs. Due to their capabilities, they received the patronage of Genghis Khan and subsequent generations, earning the confidence of the ruling Mongol authority. As a result, they were granted significant powers within the state. Methods: The study relied on the analytical method to analyze historical texts, compare them with others, and discuss them accurately. Results: The study yielded several results, including the minister's keen interes
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The Boltzmann transport equation is solved by using two- terms approximation for pure gases and mixtures. This method of solution is used to calculate the electron energy distribution function and electric transport parameters were evaluated in the range of E/N varying from . 172152110./510.VcmENVcm
The electron energy distribution function of CF4 gas is nearly Maxwellian at (1,2)Td, and when E/N increase the distribution function is non Maxwellian. Also, the mixtures are have different energy values depending on transport energy between electron and molecule through the collisions. Behavior of electrons transport parameters is nearly from the experimental results in references. The drift velocity of electron in carbon tetraflouride i
The research deals with metaphors as being one of the primary means used by Lyudmila Ulitskaya when writing the novel " Sincerely Yours Shurik ", to form diverse and multifaceted collective female images of representatives of the classic psychological patterns presented in the work. This research reflects the results of the study related to the work of Lyudmila Yevkinevna Ulitskaya, an actress of modern Russian prose. The novel "The Sincerely to You Shorek" is one of Ludmila Ulitskaya's creations (the year of writing - 2003), which, like her other works, is distinguished by a unique presentation style, rich vocabulary, lexical and semantic diversity, and a special style of writing. writer. The main objective of the research is to look at th
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