Comparative Accuracy of Cone-Beam Computed Tomography and Clearing Technique in Studying Root Canal and Apical Morphology of Mandibular Canines

Introduction: Knowledge about root canal anatomy improves the long-term prognosis of endodontic treatment. This study aimed to investigate the accuracy of cone-beam computed tomography (CBCT) in assessment of morphology of root canal and apex in mandibular canines compared with the clearing technique. Methods and Material: In this in vitro study, 33 extracted mandibular canines were subjected to CBCT with 0.1 mm voxel size. Number and type of canals, prevalence of accessory canals, anastomosis, apical delta and distance from apical constriction (AC) to apical foramen (AF) and to anatomic apex (AA) and also distance from AF to the AA were determined on CBCT scans. After access cavity preparation, a #8 K file was passed through the main apical foramen. Its direction and distance from anatomic apex was determined under a stereomicroscope. After clearing and staining of teeth, other criteria were determined with stereomicroscope under 16× magnification and served for comparison with CBCT data. The agreement of two methods were evaluated by intra-class correlation and kappa coefficients for quantitative and qualitative data, respectively. Results: Most (93.9%) canine teeth were Vertucci’s type I, followed by type III configuration in both CBCT and clearing techniques. The results of both techniques were not in agreement for assessment of accessory canals, however acceptable agreement was noted between them for detection of apical delta and also assessment of apical foramen deviation in buccolingual and mesiodistal directions. Both of two techniques had excellent agreement for evaluating the distances from AF to AA, AC to AF and AC to AA. Conclusions: CBCT is a reliable tool in assessment of root canal and apical topography in mandibular canines, however its use in accessory canal detection is not recommended.Keywords: Canine Tooth; Clearing Technique; Cone-Beam Computed Tomography; Tooth Ape

Design and Analysis of Pseudospin-Polarized Ultra-Wideband Waveguide Supporting Hybrid Spoof Surface Plasmon Polaritons

In this study, novel low-loss waveguides and power dividers for ultra-broadband surface plasmon polaritons (SPPs) are introduced. This article uses complementary metasurfaces in place of traditional SPP, which are typically produced as metasurface unit cells on the dielectric sublayer. It has been demonstrated that the use of complementary metasurfaces considerably improves wave confinement and inhibits wave propagation. Because of this, it is anticipated that waveguides and power dividers made from these complimentary unit cells will have significantly lower losses and greater bandwidth than SPP used in traditional devices. In the frequency range of 0 GHz to 100 GHz, waveguides and bent waveguides with complementary metasurface unit cells exhibit insertion loss greater than 0.5 dB. Utilizing complementary metasurfaces, symmetric and asymmetric power dividers have been created and researched. The results of the simulation have shown that using this type of unit cell in the construction of microwave devices is advantageous.Comment: 13 pages 12 figure

The Impact of Planning on Accuracy and Complexity in Oral Production of Male and Female English as a Foreign Language (EFL) Learners

Over the years, researchers have been trying to help learners to approach a task in an effective way to promote their second language (L2) production and development. Researchers have found that giving planning time to learners can improve their L2 development (Foster Skehan, 1996, Wendel, 1997). However, a few current findings about task planning are non comprehensive and nonsystematic. To fill this gap, this study examined the effects of both planning conditions and gender on learners’ oral performance in terms of accuracy and complexity among 40 Iranian students at an intermediate level. A total number of 40 participants based on an interview were selected for this study. Based on planning conditions, the participants were assigned to planning and non planning groups. Secondly, they were divided into male and female groups. The findings revealed that 10-minute planning, in comparison with no planning time, improved the accuracy and complexity of participants’ oral performance. Also, results regarding the effects of gender clarified that gender did not have any effect on the participants’ oral performance in terms of accuracy and complexity

Structural Pattern of Explaining Test Anxiety Based on Personality Traits: Assessing the Mediating Role of Cognitive and Metacognitive Strategies

Background and Aim: Academic performance of students is an indicator by which their learning and progress is judged and many individual and environmental factors are effective in academic performance. The aim of the present study was to provide a structural model for explaining exam anxiety based on personality traits: evaluating the mediating role of cognitive and metacognitive strategies. Methods: The statistical population of the present study was made up of all female students of the second secondary school in Tehran in the academic year of 2018-19. The sampling method was a multi-stage cluster random method and the sample size was 421 people. The research tools include the five-factor questionnaire of Neo Costa and Makri (1989); Sarason et al.'s test anxiety scale (1956) and Dawson and McEnery's Cognitive and Metacognitive Strategies Questionnaire (2004). The structural equation modeling method was used to analyze the data. Results: The total path coefficient between personality neuroticism factor (p<0.01, β=0.492) and test anxiety is positive and significant at 0.01 level. Also, the total path coefficient between personality openness factor (p<0.01, β=0.186) and test anxiety was negative and significant at 0.01 level. The path coefficient between cognitive strategies and exam anxiety (p<0.05, β=0.196) on the one hand and the path coefficient between metacognitive strategies and exam anxiety (p<0.01, β=0.231) on the other hand The other was negative and significant at 0.05 and 0.01 levels, respectively. Indirect effect of conscientiousness traits (p<0.01, β=0.126), openness (p<0.01, β=0.121) and extraversion (p<0.01, β=0.079) Personality has a negative effect on test anxiety and is significant at the 0.01 level. On the other hand, the indirect effect of neuroticism (p<0.01, β=0.062) on exam anxiety was positive and significant at the 0.01 level. Conclusion: It is concluded that the structural model of the explanation of exam anxiety based on personality characteristics: evaluation of the mediating role of cognitive and metacognitive strategies can be applied

Investigation of Strategies to Improve the Quality of International Exhibitions with Smart Technology Approach

The study seeks to do a pathological process for Tehran exhibition spaces and provide a solution for responsive space design to meet the needs of international exhibition by looking at the phenomenon of smart building. In this study, after examining the problems associated with existing and potential obstacles, it has been tried to design an appropriate space by using smart technology through explaining the available criteria and standards for exhibition space and also reviewing and analyzing successful examples of internal and external contexts and putting together the important indicators in an suitable and at the same time an economic attractive and ideal environment for users and comparison with the current situations and defects, which seems that besides preserving and conserving energy at high-traffic public places, provides a good physical condition for visitors. Localization and solving defects and possible barriers to hold exhibitions in order to attract more domestic and foreign audiences and promoting areas of mass communication are other objectives of this research. In order to perform the various stages of the thesis, we firstly describe, analyze and understand the current situation and then determine an outlook of ideal conditions and finally employ the result to design the space according to the exhibition space standards based on smart technology

Regeneration of musculoskeletal injuries using mesenchymal stem cells loaded scaffolds: review article

An increase in the average age of the population and physical activities where the musculoskeletal system is involved as well as large number of people suffering from skeletal injuries which impose high costs on the society. Bone grafting is currently a standard clinical approach to treat or replace lost tissues. Autografts are the most common grafts, but they can lead to complications such as pain, infection, scarring and donor site morbidity. The alternative is allografts, but they also carry the risk of carrying infectious agents or immune rejection. Therefore, surgeons and researchers are looking for new therapeutic methods to improve bone tissue repair. The field of tissue engineering and the use of stem cells as an ideal cell source have emerged as a promising approach in recent years. Three main components in the field of tissue engineering include proper scaffolds, cells and growth factors that their combination leads to formation of tissue-engineered constructs, resulting in tissue repair and regeneration. The use of scaffolds with suitable properties could effectively improve the tissue function or even regenerate the damaged tissue. The main idea of tissue engineering is to design and fabricate an appropriate scaffold which can support cell attachment, proliferation, migration and differentiation to relevant tissue. Scaffold gives the tissue its structural and mechanical properties, for instance flexibility and stiffness that is related with the tissue functions. Biomaterials used to fabricate scaffolds can be categorized into natural or synthetic biodegradable or non-biodegradable materials. Polymers are the most widely used materials in tissue engineering. Growth factors are a group of proteins that cause cell proliferation and differentiation. Two main cell sources are specialized cells of desired tissue and stem cells. However, according to the low proliferation and limited accessibility to the cells of desired tissue, stem cells are better suggestion. Combination of mesenchymal stem cells harvested from bone marrow, adipose tissue and cord blood with proper scaffolds and growth factors could be a useful method in treatment of skeletal injuries. In this review paper, we focus on the application of mesenchymal stem cells in the repair of damaged bone, cartilage, meniscus, ligaments, tendons and spine tissue

Tracing Translational Footprint by Ribo-Seq: Principle, Workflow, and Applications to Understand the Mechanism of Human Diseases

RNA-seq has been widely used as a high-throughput method to characterize transcript dynamic changes in a broad context, such as development and diseases. However, whether RNA-seq-estimated transcriptional dynamics can be translated into protein level changes is largely unknown. Ribo-seq (Ribosome profiling) is an emerging technology that allows for the investigation of the translational footprint via profiling ribosome-bounded mRNA fragments. Ribo-seq coupled with RNA-seq will allow us to understand the transcriptional and translational control of the fundamental biological process and human diseases. This review focuses on discussing the principle, workflow, and applications of Ribo-seq to study human diseases

Development and validation of Islamic quality of life questionnaire

The quality of life is mainly measured by multiple conceptual frameworks which neglect the cultural-religious context of the societies. Hence, there is not a unique instrument to assess life quality. The present study strives to develop and validate a quality of life questionnaire in light of Javadi Amoli’s view. In this study, the researcher-made questionnaire has been answered by 400 bachelor students. Javadi Amoli’s books have been consulted for developing the questionnaire. The validity of the questionnaire has been confirmed by content validity, face validity and, construct validity (using factor analysis and measuring correlation of identified components with total questionnaire). After ensuring content validity and consulting Bartlett's test and Kaiser-Mayer-Olkin index, factor analysis has been performed using principal component analysis and varimax rotation. The results oriented toward four dimensions as God, others, self, and nature which explained 36.5% of the variance. The reliability of the questionnaire has been measured using split-half method and Cronbach's alpha, and reported as 0.63 and 0.89, respectively. The reliability of the extracted dimensions has been 0.87, 0.88, 0.80, and 0.81, respectively. Accordingly, findings of the present research acknowledges the questionnaire to be purposeful and efficient