Background: 37% phosphoric acid (PA) is the traditional enamel etching technique prior to bracket adhesion, yet it has been implicated in numerous enamel injuries. The purpose of the current study was to create a calcium phosphate (CaP) etching paste in a simplified capsule formula that can underpin clinically adequate bracket bond strength without jeopardizing the integrity of enamel upon the debracketing procedure. Materials and Methods: micro-sized hydroxyapatite (HA) powder was mixed with 40% PA solution to prepare experimental acidic CaP paste. Sixty human premolars were assigned into two groups of 30 each. Enamel conditioning was accomplished using 37% PA-gel for control group and CaP paste for experimental group. Each group was further divided into two subgroups regarding the water storage (WS) period (24 h and 30 days). Shear bond strength (SBS) test conducted with examination of debonded surfaces for adhesive remnants and enamel damage using a digital microscope. Results: CaP paste produced significantly lower SBS values than PA (p < 0.01), yet sufficient for clinical use. PA etching caused often cracked enamel surfaces with excessive retention of adhesive remnants (mainly ARI scores 2 and 3). Contrarily, enamel treated with the experimental CaP paste exhibited smooth, unblemished surfaces mostly clean of adhesives residues (scores 0 and 1). Conclusion: a newly developed CaP paste in a capsule formula fosters clinically adequate bracket adhesion with a sustained bonding performance, allows a harmless bracket removal with minimal or no adhesive residues on debonded surfaces; thus, it can be introduced as a suitable alternative to PA.
Stick-slip is kind of vibration which associated with drilling operation in around the bottom hole assembly (BHA) due to the small clearance between drill string & the open hole and due to the eccentric rotating of string. This research presents results of specific experimental study that was run by using two types of drilling mud (Fresh water Bentonite & Polymer), with/without Nanoparticle size materials of MgO in various ratios and computes the rheological properties of mud for each concentration [Yield point, plastic viscosity, Av, PH, filter loss (30 min), filter cake, Mud Cake Friction, Friction Factor]. These results then were used to find a clear effects of Nanoparticle drilling mud rheology on stick - slip strength by sev
... Show MoreThe study of biomechanical indicators in the arc of the run and the upgrading stage is one of the important variables that affect the nature of the upgrading and thus affect the result of the race due to the importance of these stages and the consequent variables during the last steps. That’s why, the jump-trainings based on assistant means or body weight positively affect the step-time for each of the three steps in the acceleration arc. As well as, it focuses on the momentary strength of each step at this stage. It also significantly affects the speed of motor performance to suit the activity in which the runner needs to perform perfect steps with high flow in order to convert the horizontal speed to a vertical one. This is achieved thr
... Show MoreThe article is devoted to the issue of word-formation motivation, which does not lose its relevance and plays a role not only in disclosing formal-semantic relations between words of one language and has not only theoretical, but also applied significance. The authors consider word-formation motivation consistently in its varieties in a comparative way on the materials of so different languages as Russian and Arabic and approach the mechanism of achieving semantic equivalence of translation. To the greatest extent, word-formation activity today, due to objective reasons, affects some special branch (technical, medical, etc.) vocabulary, which is increasing from year to year in national dictionaries. This extensive material, selected
... Show MoreThe research aimed to identify the level of job security, the level of sports institutional performance, and the relationship, contribution and impact of job security to sports institutional performance from the point of view of workers in the Iraqi Ministry of Youth and Sports. The descriptive approach was adopted in the manner of correlational relationships on a sample of (400) individuals who were randomly selected by (33.333%) of the employees working in the institutions at the headquarters of the Ministry of Youth and Sports, amounting to a total of (2293) individuals for the sports season (2022-2023), and they are naturally distributed among (13) main institutions in the formations of the headquarters of this ministry, and after adopt
... Show MoreThe shape dimensions and characteristics of pollen grains and seeds have importance in distinguish among species. Therefore, the present study included morphological characteristics of pollen grains and seeds for eight species belonging to eight genera of the family Brassicaceae and these species are: Alliaria petiolata (M.Bieb) Cavara et Grand, Aubrieta parviflora Boiss, Cardamine hirsuta L., Crambe orientalis L., Eromobium aegyptiacum (Spreng.) Schweinf.et Asch.ex Boiss., Parlatoria cakiloidea Boiss., Sterigmostemum sulphureum (Banksetsol.) Bornm. Neotorularia torulosa (Desf.) Hedge & J. Leonard. The pollen grains were studied in morphological and full measurements were taken, the study showed that the majority of the pollen grai
... Show MoreThe current research aims to determine the role of strategic leadership in achieving organizational excellence. In this context the sample of the research consist of 123 managers .The research problem can be summarized as {what is the role of strategic leadership in achieving organizational excellence}which resulted in a number of sub-questions and its goal was to explain the theoretical philosophy and intellectual expositions of this variables because of they are vital variables imposed by the current situation. To achieve research objectives we had use the questionnaire as a tool to collect data and information after verifying the validity and dependency of the measures. A number of statistical techniques and tools had been use
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The research aims to shed light on strategic cohesion and its dimensions represented by (strategic logic, organizational excitement, organizational founding, organizational synergy) and measure its impact on achieving organizational prosperity and its dimensions represented by (intellectual capital, innovation, infrastructure, organizational agility, sustainable competitive advantage). The research problem emerged by raising the main question, which is: Does the management of the researched company realize the importance of practicing strategic cohesion and its role in achieving organizational pros
... Show MoreThis research aims at to identify the extent to which creative thinking skills Impact the change &development of Administrative Leadership styles In Administrative Leadership of the Medical City Department. Identify the nature of the relationship between them, determine the prevailing leadership style, &measure the level of creative thinking skills they have. In order to achieve the objectives of the research, the descriptive analytical method was adopted.
The research tool consisted of a questionnaire consisting of (61) paragraphs, in addition to the interview & observation. The research sample consisted of (170) administrative leaders in the upper &middle organizational levels. The
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