Background: The purpose of this study was to evaluate the effect of in vitro long-term simulation of oral conditions on the bond strength of PEEK CAD/CAM lingual retainers.

Material and methods: The sample consisted of 12 PEEK CAD/CAM retainers each composed of 2 centrally perforated 3x4mm pads joined by a connector. They were treated by 98% sulfuric acid for 1 minute and then conditioned with Single Bond Universal and bonded to the lingual surface of premolar teeth by 3M Transbond TM System. Half of the retainers were artificially aged using a 30-day water storage and 5000 thermocycling protocol before bond strength testing to compare with the non-aged specimens.

Results: The artificially aged retainers showed a marginally

In this work, multilayer nanostructures were prepared from two metal oxide thin films by dc reactive magnetron sputtering technique. These metal oxide were nickel oxide (NiO) and titanium dioxide (TiO2). The prepared nanostructures showed high structural purity as confirmed by the spectroscopic and structural characterization tests, mainly FTIR, XRD and EDX. This feature may be attributed to the fine control of operation parameters of dc reactive magnetron sputtering system as well as the preparation conditions using the same system. The nanostructures prepared in this work can be successfully used for the fabrication of nanodevices for photonics and optoelectronics requiring highly-pure nanomaterials.

The purpose of this paper is to study a new types of compactness in the dual bitopological spaces. We shall introduce the concepts of L-pre- compactness and L-semi-P- compactness .

he public federal budget of the state includes estimated figures for state revenues and expenditures for the next fiscal year. The estimation process is one of the main parts of the preparation of the general budget of the state and the accuracy in the estimation of revenues and expenditures of the most important principles that should be based on the process of making estimates and should not overestimate the assessment process to ensure the availability of funds in the future in all cases, which lead to unfair distribution of allocations, so the research aims to study The case of preparing the budget in the Directorate and how to estimate the expenditure in, by the analysis of operating budgets and identify deviations in the implementa

This 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

Abstract: 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

he paper presents the results of exposure of normal concrete to high temperatures (400 and 700°C). In addition to the exposure of steel reinforcement bar Ø 12 mm, where two types of steel reinforcement burning situations were performed. Directly exposed to high temperatures (400 and 700°C) and others were covered by concrete layer (15 mm). From the experimental results of fire exposure for 1 hour of 400 and 700°C and gradually cooled, it was found that the residual average percentage of compressive strength of concrete was 85.3 and 41.4%, while the residual average percentage of modulus of elasticity of concrete was 75 and 48%, respectively. The residual average percentage of yielding tensile stress (Ø 12 mm) after burning and cooling

Our aim in this paper is to study the relationships between min-cs modules and some other known generalizations of cs-modules such as ECS-modules, P-extending modules and n-extending modules. Also we introduce and study the relationships between direct sum of mic-cs modules and mc-injectivity.