Objectives To tailor composites of polyethylene–hydroxyapatite to function as a new intracanal post for the restoration of endodontically treated teeth (ETT). Methods Silanated hydroxyapatite (HA) and zirconium dioxide (ZrO2) filled low-density polyethylene (LDPE) composites were fabricated by a melt extrusion process and characterised using infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The flexural strength and modulus were determined in dry state and post ageing in simulated body fluid and fractured surfaces analysed by SEM. The water uptake and radiographic appearance of the experimental composites were also measured and compared with a commercially known endodontic fibre post. Data were submitted to one-way analysis of variance (ANOVA) and post hoc Tukey multiple comparison tests at a level of significance P < 0.05. Results The LDPE/HA composites were structurally flexible and the HA content had a significant effect on the flexural strength and modulus. A univariate analysis of variance showed no significant differences in modulus and strength (P < 0.05) post accelerated ageing in simulated body fluid with very low water uptake. The melting point of the LDPE/HA composites ranged between 135 and 136 °C, which would facilitate removal in case of retreatment using conventional dental heating devices. The inclusion of HA reduced the damping thereby enhancing dimensional stability, whilst the addition of zirconia yielded a semi-translucent material that was sufficiently radiopaque, comparable to commercial posts, thus yielding aesthetic materials. Conclusions Innovative materials for restoration of ETT were developed; offering considerable benefits over the currently available material in terms of biomechanical and thermal properties. Clinical significance This study provided a new option for the development of a new intracanal post made up of functional and aesthetic composites.
In light of increasing demand for energy consumption due to life complexity and its requirements, which reflected on architecture in type and size, Environmental challenges have emerged in the need to reduce emissions and power consumption within the construction sector. Which urged designers to improve the environmental performance of buildings by adopting new design approaches, Invest digital technology to facilitate design decision-making, in short time, effort and cost. Which doesn’t stop at the limits of acceptable efficiency, but extends to the level of (the highest performance), which doesn’t provide by traditional approaches that adopted by researchers and local institutions in their studies and architectural practices, limit
... Show More: The Aluminium (Al) material emerged as a plasmonic material in the wavelength ranges from the ultraviolet to the visible bands in different on-chip plasmonic applications. In this paper, we demonstrate the effect of using Al on the electromagnetic (EM) field distribution of a compact hybrid plasmonic waveguide (HPW) acting as a polarization rotator. We compare the performance of Al with other familiar metals that are widely used as plasmonic materials, which are Silver (Ag) and Gold (Au). Furthermore, we study the effect of reducing the geometrical dimensions of the used materials on the EM field distributions inside the HPW and, consequently, on the efficiency of the polarization rotation. We perform the study based o
... Show MoreThe aim of research is to identify the effect of using Waks strategy upon acquiring the psychological concepts and mind habits for students in the college of education. An experimental design with a partial adjustment of two experimental and control groups as well as a posttest were employed. The researcher divided the study sample into two groups: group one consisted of (38) students to represent the experimental group that was taught according to the waks strategy, and group two consisted of (35) students to represent the control group that was taught according to the traditional method. The sample was chosen based on some variables namely (Intelligence, Prior knowledge). The researcher has designed the research tools as th
... Show MoreThe development of the world, and in light of the intensity of competition highlighted the need to research and create a sustainable competitive advantage is sustained from an internal source in the company earned by the scarcity and difficulty of imitation by competitors, and this source is green innovation. In order to achieve the objective of the research, which is the diagnosis and analysis of the relationship between green innovation (in products, processes) and sustainable competitive advantage in the group of companies Kronji, was developed a default model of the research reflects the nature of the relationship and influence among its variables, the research adopted the questionnaire as a key tool for collecting data and i
... Show MoreThe Ground Penetrating Radar (GPR) is frequently used in pavement engineering
for road pavement inspection. The main objective of this work is to validate
nondestructive, quick and powerful measurements using GPR for assessment of subgrade
and asphalt /concrete conditions. In the present study, two different antennas
(250, 500 MHz) were used. The case studies are presented was carried in University
of Baghdad over about 100m of paved road. After data acquisition and radar grams
collection, they have been processed using RadExplorer V1.4 software
implementing different filters with the most effective ones (time zero adjustment and
DC removal) in addition to other interpretation tool parameters.
The interpretatio
The need for detection and investigation of the causes of pollution of the marshes and submit a statistical study evaluated accurately and submitted to the competent authorities and to achieve this goal was used to analyze the factorial analysis and then obtained the results from this analysis from a sample selected from marsh water pollutants which they were: (Electrical Conductivity: EC, Power of Hydrogen: PH, Temperature: T, Turbidity: TU, Total Dissolved Solids: TDS, Dissolved Oxygen: DO). The size of sample (44) sites has been withdrawn and examined in the laboratories of the Iraqi Ministry of Environment. By illustrating SPSS program) the results had been obtained. The most important recommendation was to increase the pumping of addit
... Show MoreAmygdalin (d-Mandelonitrile 6-O-β-d-glucosido-β-d-glucoside) and its semi synthetic product is Laetrile ( also called vitamin B17): a natural cyanogenic glycoside occurring in the seeds of some edible plants, such as bitter almonds and peaches. Early in the 19th century, Amygdalin was first isolated in 1830 by two French chemists, Robiquet and Boutron-Charlard, as active components in various fruit pits and raw nuts. However, the systematized study of vitamin B17 started when chemist Bohn (1802) discovered that a hydrocyanic acid is released during distillation of the water from bitter almonds. The various pharmacological effects of Laetrile include antiatherogenic, activity in renal fibrosis, pulmonary fibrosis, immune regulation, ant
... Show MoreSummaryBackground: Rotavirus infection is the most commoncause of watery viral diarrhea in children younger than 5 years of age; it is a major cause of childhood morbidity and mortality.Objective:The aim of the study is todetermine the clinical picture, age distribution of patients with rotavirus infection and their maternal educational background.Patients &methods: A total of 202 patients suffering from diarrhea were included in this study, over 6 months period( from 1stof March 2011to 30th of August 2011),in Children Welfare Teaching hospital. History and physical examinationwere carried out, anthropometrics measures were done and plotted on Centers for Disease Control& World Health Organization charts to determine the nut
... Show More
Debate is a teaching strategy in nursing education that enhances students' critical thinking. Although debate can be an effective teaching strategy, it is not without limitations. This article discusses the advantages and disadvantages of debate as a teaching strategy in nursing. Also, evaluating debates and choosing topics are highlighted.