The experiment was conducted to study the effect of sodium chloride (NaCl) at the concentrations of 0.0, 0.5, 1.0 and 1.5% on the callus cells. The Iraq wheat variety was grown in vitro for the purpose of knowing the effect of salt stress on some indicators and cellular components of callus by using a randomized complete design, at the laboratories of tissue culture propagation date palm unit in the College of Agriculture / University of Kufa during the period 2014-2015. Fresh and dry weight, the rate of absolute growth, percentage of dry matter of callus, content of the callus cells of proline, total soluble carbohydrates, sodium and potassium ions, effectiveness of the enzymes catalase and peroxidase study shock salt proteins in callus we
... Show MoreJob stress is considered one of the most important obstacles that may appear in the work field. In order to deal with the obstacles and challenges , the idea to deal with job stress has come to address job stress as one of the most important trends that enable organizations to face those challenges through focusing on the role of job stress and the organizational climate of the organization.
The research deals with two variables: the job stress as an independent variable, and the organizational climate as a dependent one. Each variable includes five sub-dimensions. These dimensions have been involved in an interaction to form
... Show MoreObjective: preparing exercises for the third intensity zone for strength and speed for the legs, and identifying their effect on some physiological and biochemical indicators for (the level of lactic acid concentration, the concentration of sodium bicarbonate, the concentration level of (potassium K+) and (sodium Na+) in the blood, and the number of breathing times (RF) Research methodology: the experimental research method was adopted by designing the experimental and control groups on a sample of Army Sports Club players amounting to (16) players, deliberately selected (100%) from their community using a comprehensive enumeration method, and then divided into two groups of equal number, After determining the tests for physiologica
... Show MoreBackground: The demand for esthetic orthodontic appliances is increasing; so the esthetic orthodontic archwires were introduced. Among them, Teflon and Epoxy coated stainless steel archwires. The amount of force available from the archwire depends on the structural properties and susceptibility to corrosion. All metallic alloys are changed during immersion in artificial saliva, chlorhexidine mouthwash andtoothpaste, but their behaviors differ from one type to another. They corrode at different rates, which lead to decrease the amount of force applied to the teeth. This in vitro study was designed to evaluate the corrosion pits in stainless steel archwires coated with Teflon and with Epoxy in dry and after immersion in artificial saliva, chl
... Show MoreBackground: The combination of thermoplastic nylon resin materials and auto polymerizing resin is necessary in some situation for repair and adjustment. This study evaluated shear bond strength between thermoplastic nylon material (flexible) and auto polymerizing acrylic resin subjected to holes and silica coated layer. Materials and Method: Forty five (45) specimens were prepared from flexible acrylic bonded to auto-polymerizing acrylic resin and divided into three groups according to the surface treatments as follows: Group A: 15 specimens of flexible acrylic bonded with cold-cure acrylic by holes. Group B: 15 specimens of flexible acrylic bonded with cold-cure acrylic by silica coated layer. Group C: 15 specimens of flexible acrylic bon
... Show MoreBackground and objectives: This study aimed at testing the effect of plastic sleeve or barrier, used to cover the guide of the light cure unit to prevent cross-infection, on the shear bond strength and site of bond failure of stainless steel and ceramic orthodontic brackets. Materials and methods: Forty orthodontic brackets; twenty stainless steel and twenty ceramic brackets bonded to forty extracted human maxillary first premolars using light cure adhesive cured with and without the use of a protective plastic barrier on the guide. Comparing the effect of this barrier on the shear bond strength and adhesive remnant index was performed using an independent t-test and Chi-square test. Results: The protective barrier had decreased the shear b
... Show MoreBackground: Reduction in bond strength when bonding was done immediately after intracoronal bleaching procedure has been recognized. The purpose of this study is to assess the effect of antioxidants (10% sodium ascorbate (SA), 0.1M thiourea and7% sodium bicarbonate (SB)) on reversing bonding strength of composite resin to bleached dentin. Materials and method: Sixty upper 1st premolar teeth, were selected, the crowns of the teeth were embedded in acrylic resin blocks exposing a flat dentin from the buccal surface, then divided into 6 groups (10 samples each). Bleaching for the experimental groups was performed using 35% hydrogen peroxide bleaching gel (pola–office).Group A (Negative
... Show MoreThis study aims to investigate the effect of changing skins material on the strength of sandwich plates with circular hole when subjected to mechanical loads. Theoretical, numerical and experimental analyses are done for sandwich plates with hole and with two face sheet materials. Theoretical analysis is performed by using sandwich plate theory which depends on the first order shear deformation theory for plates subjected to tension and bending separately. Finite element method was used to analyse numerically all cases by ANSYS program.
The sandwich plates were investigated experimentally under bending and buckling load separately. The relationship between stresses and the ratio of hole diameter to plate width (d/b) are built, by
... Show MoreIn this work polymeric composites were done from unsaturated polyester as a matrix reinforced with glass fiber type (E-glass) with two different volume fraction 20% & 40%. Fatigue tests showed that the number of fatigue cycles to failure limit for samples reinforced with uniform (woven Roving 0-90°) E-glass fiber and random (continuous fibers) with volume fraction 40% more than that for the same samples with volume fraction 20%. Also the fatigue results showed that the uniform samples failed with fatigue cycles more than that of random.