Thermodynamic Assessment of the As-Zn and As-Ga-Zn Systems

We have performed a thermodynamic assessment of the As-Zn and As-Ga-Zn systems. The systems are assessed based on the CALPHAD method and using available first principles and experimental data. Using the optimized set of parameters found in this work, the calculated As-Zn binary phase diagram, isoplethal sections and the monovariants lines of the As-Ga-Zn ternary system are presented. The comparison of the calculated diagrams with the experimental and first principles data shows good agreement

The phase equilibria in the Au-In-Ga ternary system

The phase equilibria of the Au–In–Ga system were investigated for the first time using Differential Thermal Analysis (DTA), X-Ray Diffractometry (XRD), Energy Dispersive X-ray Spectroscopy (EDS) and Scanning Electron Microscopy (SEM). A new ternary phase (Au2InGa2) with the hexagonal structure (P63/mmc) was discovered which melts incongruently at 394 °C. From the experimental results, several invariant reactions have been identified and discussed

Anatomic Features of C-shaped Mandibular Second Molars in a Selected Iranian Population Using CBCT

Introduction: The aim of this retrospective study was to analyze the frequency of C-shaped root canal configuration and characterize mandibular root canal morphology using cone-beam computed tomography (CBCT) with 3D images in an Iranian population. Methods and Materials: This study consisted of retrospective evaluation of CBCT images from 231 adult patients (153 with bilateral second mandibular molars). Two endodontists examined 384 mandibular second molars of a population in Tabriz, Iran to determine the presence of C-shaped canals and their anatomical characteristics. Root canal configurations were categorized at three different levels. Bilateral or unilateral occurrence of C-shaped canals and their relationship to gender, age and tooth position were examined and statistically analyzed using chi squared test and Fisher’s exact test in SPSS 17. The significance level was set at 0.05. Results: Of 384 mandibular second molars examined, 82 (21.4%) molars from 58 patients had a C-shaped root canal configuration. The prevalence of bilateral C-shaped canals was 15.6% amongst 153 patients with bilateral mandibular second molars. There were no significant differences in the distribution of C-shaped canals with respect to gender or age (P=0.06 and P=0.86, respectively). Only 4 teeth (4.9%) had the same root canal configuration from the orifice to the apex. In the remainder of the teeth, the cross-sectional root canal configuration changed at different levels of the root. Conclusion: There were significant variations in the number of roots and canal morphology in mandibular second molars, which should be considered during debridement and obturation of the root canal system.Keywords: C-shaped Canal; Canal Configuration; Cone-beam Computed Tomography; Mandibular Second Mola

Application of Activity-Based Costing Method in Calculation the prime Cost of Medical Students’ Education

Introduction: Calculating the prime cost of student education is one of the requirements for achieving the goals of the country's development programs in terms of improving the efficiency of universities. It is also one of the most important goals of the transformation and innovation program in medical education. This study aimed to calculate the prime cost of education for students of the School of Health at Bam University of Medical Sciences using activity-based costing method.Methods: The present study is a descriptive cross-sectional and retrospective study. The required data were collected through designed forms. Then, the service prime cost was calculated using the activity-based costing method and Excel 2016 software.Results: The results showed that the total cost of Bam School of Health was 31016503943 Rials. Of this amount, the environmental health group has the highest (22.53%), and the health services management group has the lowest (9.34%) costs among the existing educational groups. Also, among the cost chapters, the largest share is related to the expenses of the first chapter, salaries and wages.Conclusion: In this study, a cost analysis was performed by cost chapters.  This approach in cost analysis helps planners to estimate a fixed cost enabling them to determine a fixed level of benefit and creating the lowest possible cost. It will help universities to be more accurate and efficient in using the resources available to them

Effectiveness of Mouth Washes on Streptococci in Plaque around Orthodontic Appliances

Background and Purpose. Fixed orthodontics may be associated with accumulation of Mutans Streptococci (MS), enamel demineralization, and an increased number of carious lesions, predominantly in sites adjacent to brackets. This study was undertaken to assess the effectiveness of Listerine, Oral-B, and Ortho-kin on the accumulation of MS in plaque around orthodontic brackets. Materials and Methods A double-blind randomized cross-over clinical trial on 25 orthodontic patients, classified into 6 groups was done to assess MS in plaque and saliva with the side specific modified Strip-Mutans technique and the plaque (PI) was measured before and after rinsing using 3 types of commercial mouth-rinses. A washout period (3 weeks) was awaited between using each mouth-rinse and the data was analyzed via Wilcoxon and Kruskal Wallis statistical tests. Results. This study of 25 patients, 5 men and 20 women, with an average age of 19 ± 6/3 assessed the effectiveness of mouth-rinses on MS. Our results showed that Ortho-kin had a better effect than Oral-B and Listerine (P < 0/09). Ortho-kin also had better effects than Oral-B and Listerine on plaque accumulation (P < 0/001). Conclusion. Ortho-kin showed better effects on decreasing MS and PI because it contained chlorhexidine

Thermodynamic re-assessment of the Zn–P binary system

Thermodynamic phase diagrams are the cornerstones to develop synthesis of new materials. Zinc phosphide has evolved into a prospective semicontuctor for next generation solar cells, thanks to its abundance and functional properties. Here we derive an optimized Zn-P binary diagram, and compare it to two previously available assessments. We solve some of the artefacts and clarify the methodology to obtain the Gibbs free energy, reaching an accurate description of the phases. This work is important for the synthesis of zinc-phosphide in the form of thin film and nanostructures

Thermodynamic description of the Au-In-Ga ternary system based on the CALPHAD method

There has recently been a considerable attention to the possible role of semiconductor nanowires for future device applications. To make this development feasible, precise control over the growth mechanism is required. In the Vapor-Liquid-Solid growth, the most common growth mechanism, gas phase precursors decompose in presence of catalytic particles and after supersaturating the particles, solid nanowires start to nucleate and grow from the seed particle. The knowledge on the equilibrium state of the seed particle is useful to understand the growth mechanism. In this work, we investigated the thermodynamic description of the AuIn-Ga ternary system by calculating its phase diagram. Using this phase diagram, the state of the gold particles in Au-seeded nanowires containing In and Ga can be explained. The phase diagram was investigated experimentally and computationally. The most common technique for calculating phase diagrams, the CALPHAD technique, was used for the calculations. The measurements on the system were performed using relevant thermal, crystallographic, structural and compositional analysis techniques. The most important results of the measurements were the identification of a new ternary phase, the ternary solubilities and the phase transition temperatures. These enabled us to optimize the calculated phase diagram and hence the thermodynamic description of the system