The microstructure and microtexture of zirconium oxide films studied by transmission electron backscatter diffraction and automated crystal orientation mapping with transmission electron microscopy

A detailed characterization of nanostructured thin zirconium oxide films formed during aqueous corrosion of a nuclear-grade zirconium alloy (Zircaloy-4) has been carried out by means of two novel, ultra-high-spatial-resolution grain mapping techniques, namely automated crystal orientation mapping in the transmission electron microscope (TEM) and transmission electron backscatter diffraction (t-EBSD). While the former provided excellent spatial resolution with the ability to identify tetragonal ZrO<sub>2</sub> grains as small as ∼5 nm, the superior angular resolution and unambiguous indexing with t-EBSD enabled verification of the TEM observations. Both techniques revealed that in a stress-free condition (TEM foil prepared by focused ion beam milling), the oxide consists mainly of well-oriented columnar monoclinic grains with a high fraction of transformation twin boundaries, which indicates that the transformation from tetragonal to monoclinic ZrO<sub>2</sub> is a continuous process, and that a significant fraction of the columnar grains transformed from stress-stabilized tetragonal grains with (0 0 1) planes parallel to the metal–oxide interface. The TEM analysis also revealed a small fraction of size-stabilized, equiaxed tetragonal grains throughout the oxide. Those grains were found to show significant misalignment from the expected (0 0 1) growth direction, which explains the limited growth of those grains. The observations are discussed in the context of providing new insights into corrosion mechanisms of zirconium alloys, which is of particular importance for improving service life of fuel assemblies used in water-cooled reactors

Performance enhancement of photovoltaic-thermal modules using a new environmentally friendly paraffin wax and red wine-rGO/H2O nanofluid

Photovoltaic/thermal systems are one of the most efficient types of solar collectors because they absorb solar radiation and generate electricity and heat simultaneously. For the first time, this paper presents an investigation into the impact of red wine-rGO/H2O nanofluid and paraffin wax on the thermohydraulic properties of a photovoltaic/thermal system. The study focuses on three innovative nonlinear arrangements of the serpentine tubes. The effects of these materials and configurations are analyzed through numerical simulations. To improve the performance, environmentally friendly materials, including red wine-rGO/H2O nanofluid and paraffin wax, have been used. Various performative parameters such as electrical and thermal efficiency of the photovoltaic/thermal system, exergy, and nanofluid concentration were investigated. The results demonstrated a significant enhancement in the system’s performance when using innovative serpentine tubes instead of simple tubes for the fluid flow path. The use of paraffin C18 increases electrical efficiency, while the use of paraffin C22 improves thermal efficiency. Moreover, the incorporation of phase change materials along with the utilization of innovative geometries in the serpentine tube led to a notable improvement in the outlet temperature of the fluid, increasing it by 2.43 K. Simultaneously, it substantially reduced the temperature of the photovoltaic cells, lowering it by 21.55 K. In addition, the new model demonstrated significant improvements in both thermal and electrical efficiency compared to the simple model. Specifically, the maximum thermal efficiency improvement reached 69.2%, while the maximum electrical efficiency improvement reached 11.7%

Root Canal Morphology of Mandibular Canine in an Iranian Population: A CBCT Assessment

Introduction: The present study was conducted to assess the morphology of mandibular canines using cone-beam computed tomography (CBCT) in a north Iranian population. Methods and Materials: For the morphological assessment of mandibular canines, 150 CBCT images taken from patients for different reasons were used. The mandibular canines were examined in sagittal, coronal and axial dimensions. The canal pattern, number of roots/canals, the tooth length, the orientation of the roots and the position of the apical foramina were evaluated and the effect of gender on each variable was assessed. The obtained data were analyzed using the Chi-square and student’s t-tests. Results: According to the Vertucci’s criteria, the most common pattern was type I morphology (89.7%), followed by types III (5.7%), II (3.7%) and V (1%). No significant differences were observed between the male and female patients in terms of canal type (P>0.05). Gender difference is a factor which affected the root length and the number of mandibular canine root and root canal. There were 296 single-root and four double-root canines. The double-root canines and mandibular canine with two canals were significantly more common among men than women (P=0.00). The apical foramen was laterally positioned in 68.3% and centrally in 31.7% of the cases, and the root curvatures were mostly oriented toward the buccal region. No significant statistical difference was observed for mentioned parameters in right and left half of the jaw. Conclusion: Due the diverse morphology and the potential presence of a second mandibular canine among Iranians, dentists should perform endodontic treatments with greater care. CBCT is an accurate tool for the morphological assessment of root canals.Keywords: Canine; Cone-Beam Computed Tomography; Root Canal

Effect of sandblasting on the tensile bond strength of two permanent silicone soft liners to the denture base

Introduction: Soft liners are materials used in removable dental prostheses to maintain the health of inflamed mucous membranes. The materials bond strength to acrylic bases can be modified by several methods; One of which includes sandblasting. The aim of this study is to investigate the effect of sandblasting on the tensile bond strength(TBS) of two permanent silicone soft liners. Material & Methods: 36 dumbbell-shaped heat-cured polymethylmethacrylate acrylic specimens were fabricated in denture flasks with a length of 75 mm, width of 12 mm and a thickness of 7 mm in the thinnest section. 3 mm of the material of all specimens was cut using a low-speed diamond saw with water cooling. Then according to the surface treatment and sofliners, the specimens were divided into four groups: no surface treatment with mollosil softliner, no surface treatment with GC softliner, sandblasting with 50 μm Al2O3 particles and then using mollosil soft liner and sandblasting with 50 μm Al2O3 particles and then using GC soft liner. After polymerization of all specimens, TBS was evaluated with universal testing machine at a crosshead speed of 5 mm/min until failure. Finally, two-way ANOVA and independent T-test were used to analyzing the data. Results: The mean of TBS in the groups of sandblasting was significantly higher than other group and the mean of TBS in the group of mollosil was higher than GC group with or without sandblasting. (p=0.001) Conclusion: Sandblasting increases the TBS of silicone soft liners to the acrylic bases; moreover, Mollosil softliners are more tenacious compared to GC

Awareness and attitude of parents toward pediatric dental treatment under general anesthesia

BACKGROUND AND AIM: Dental treatment under general anesthesia is critical for non-cooperative, low aged, and special needs’ children. This study aimed to investigate the knowledge and attitude of parents about pediatric dental treatment under general anesthesia. METHODS: This was a cross-sectional study among 100 parents of children who were referred to Babol School of Dentistry (Roohani Hospital) and Babol clinic Hospital, Iran, in 2012-2013 for dental treatment under general anesthesia. The questionnaire contained questions assessing the reasons for choosing dental treatment under general anesthesia, and the advantages and disadvantages of this method of treatment and parental satisfaction. The form was completed by the parents. Data were reported using descriptive statistics and analyzed by the Spearman correlation coefficient. RESULTS: In this study, a questionnaire survey showed that the majority of parents were concerned about the health of their children and despite having some degree of awareness about side effects of general anesthesia and its high cost, they expressed a positive view toward that. A reduction of fear and anxiety and the possibility of performing several treatments in one session are among the benefits of this method. Non-cooperative children of low age with a high number of dental caries are the main recipients of this treatment method. This method was introduced to the majority of parents by the dentist treating their children. CONCLUSION: This study showed parents accepted the costs and risks of this approach to maintain the oral health of their children after it was recommended by the pediatrician. Therefore, with sufficient awareness of society toward this treatment option, we can improve children’s oral health and performance. KEYWORDS: General Anesthesia, Parental Attitudes, Parental Awareness, Pediatric Dental Treatmen

Evaluation of Musculoskeletal Disorders in the Personnel of Health Centers in Babol, Iran

Background: Work-related musculoskeletal disorders are the most important cause of lost workdays and inefficiencies, medical costs, and workforce injuries. The aim of this study was to investigate the musculoskeletal disorders in employees of Babol health centers in 2017. Methods: This cross-sectional descriptive-analytic study was conducted on 210 employees of Babol health centers. A questionnaire including demographic information and the Standard Nordic Questionnaire were used for data collection. Data were analyzed using descriptive statistics and chi-square test in SPSS 22 software. Results: The mean age of the personnel was 40.07 ± 8.46. The highest prevalence of disorders was reported in the waist (58.9%) and neck (54.1%) in the last year, and the lower back (46.9%) and neck (44.9%) in the last seven days. In the last year, 25.7% and 15.5% of the staff required the use of medical and physiotherapy services, respectively, due to disorders. There was a significant relation between behind-the-desk hours with neck (P= 0.002) and knee pain (P= 0.049). Conclusion: In order to prevent and control musculoskeletal disorders, regarding the high prevalence of them, it is necessary to program for educational workshops to increase personnel knowledge, as well as ergonomic interventions, redesigning the workplace, and using appropriate anthropometric equipment. Keywords: Musculoskeletal Disorders, Nordic Disease Questionnaire, Personnel of health center

Interleukin 35 levels in saliva of type 2 diabetic patients with moderate chronic periodontitis

Introduction: Periodontitis is a common disease in patients with diabetes. There is a significant relationship between hyperglycemic degree and severity of periodontitis, but the base of mechanism of this relationship has not been fully defined. Considering the important role of cytokines in periodontal pathogenesis and considering that there has been no study on the comparison of interleukin 35 (IL-35) in these diseases, the aim of this study was to determine the level of this salivary cytokine in patients with type 2 diabetes mellitus with generalized moderate chronic periodontitis. Material & Methods: Totally, 88 subjects (44 female, 44 males) with a mean age of 42.5±10.5 years old participated in this case control study. The subjects were divided into four groups and each group included 22 subjects: Group 1: generalized moderate chronic periodontitis patients with type 2 diabetes, Group 2: generalized moderate chronic periodontitis patients without diabetes, Group 3: diabetic patients with normal periodontium, Group 4: healthy periodontium and non-diabetic group (control) Then saliva were collected and centrifuged, the amount of IL-35 was determined with commercial ELISA kit. Data were analyzed . ANOVA and Tukey post-hoc tests were used to compare the groups. Results: The Mean±SD of IL-35 was significantly higher in the control group (22.59±8.36, p0.05). Conclusion: The salivary IL-35 level is decreased in both periodontitis and type 2 diabetes. However, diabetes mellitus does not exacerbate this decline in patients with periodontitis