Managing a Mandibular Second Premolar with Three-Canal and Taurodontism: A Case Report

Root canal anatomy diversity and aberrations are common especially in permanent dentition. A thorough understanding of the basic root canal anatomy and its diversities are necessary for successful endodontic treatment. Mandibular second premolars are usually single-rooted and have one root canal. Incidence of three separate root canals in this tooth is quite rare and taurodontism with three separate canals has never been reported in literature so far. The use of cone-beam computed tomography scan in this rare case greatly contributed to making a confirmatory diagnosis and successful nonsurgical endodontic management thereafter

A Super Non-dominated Point for Multi-objective Transportation Problem

In this paper a method to obtain a non-dominated point for the multi-objective transportation problem is presented. The superiority of this method over the other existing methods is that the presented non-dominated point is the closest solution to the ideal solution of that problem. The presented method does not need to have the ideal point and other parameters to find this solution. Also, the calculative load of this method is less than other methods in the literature

Polar Coding for Achieving the Capacity of Marginal Channels in Nonbinary-Input Setting

Achieving information-theoretic security using explicit coding scheme in which unlimited computational power for eavesdropper is assumed, is one of the main topics is security consideration. It is shown that polar codes are capacity achieving codes and have a low complexity in encoding and decoding. It has been proven that polar codes reach to secrecy capacity in the binary-input wiretap channels in symmetric settings for which the wiretapper's channel is degraded with respect to the main channel. The first task of this paper is to propose a coding scheme to achieve secrecy capacity in asymmetric nonbinary-input channels while keeping reliability and security conditions satisfied. Our assumption is that the wiretap channel is stochastically degraded with respect to the main channel and message distribution is unspecified. The main idea is to send information set over good channels for Bob and bad channels for Eve and send random symbols for channels that are good for both. In this scheme the frozen vector is defined over all possible choices using polar codes ensemble concept. We proved that there exists a frozen vector for which the coding scheme satisfies reliability and security conditions. It is further shown that uniform distribution of the message is the necessary condition for achieving secrecy capacity.Comment: Accepted to be published in "51th Conference on Information Sciences and Systems", Baltimore, Marylan

Comparison of the Penetration Depth of Conventional and Nano-Particle Calcium Hydroxide into Dentinal Tubules

Introduction: The aim of this in vitro study was to evaluate and compare the penetration depth of conventional (CH) and nano-particle calcium hydroxide (NCH) into dentinal tubules. Methods and Materials: Ninety human single-rooted teeth were instrumented by RaCe rotary system and after chemomechanical preparation were randomly divided in two equal groups (n=45). In the first group conventional CH and in the other NCH was used as intracanal medicament. After 2 weeks of incubation all roots were intentionally split at longitudinal axis and prepared for scanning electron microscope (SEM) observation. Three zones of each root, coronal, middle and apical were examined under SEM and the maximum penetration depth of the dressing material into dentinal tubules was recorded for each zone. Data were analyzed using the independent sample t test and the level of significance was set at 0.05. Results: In all of the three zones, NCH group had greater penetration depth than CH (P<0.001). In both groups the penetration depth increased from the apical section to the coronal. Conclusion: The depth of penetration of nano-particle calcium hydroxide into the dentinal tubules was significantly higher than that of conventional calcium hydroxide. The lowest penetration depth was observed in apical zone in both groups.Keywords: Calcium Hydroxide; Dentinal Tubules; Nano Particle; Penetration Depth; Tubular Penetration

The association between dietary inflammatory index and C-reactive protein in plasma and semen with semen quality: A cross-sectional study

Background: Infertility affects couples worldwide, with male factors being responsible for half of all cases. Objective: This study aimed to investigate the relationship between dietary inflammatory index (DII) and levels of C-reactive protein (CRP) in plasma and semen with the quality of semen in infertile males. Materials and Methods: In this cross-sectional study, 88 infertile men referring to Besat hospital, Tehran, Iran from December 2021-November 2022 were enrolled. A detailed questionnaire requesting information, and a 168-item semiquantitative food frequency questionnaire, were completed by participants. A food frequency questionnaire was used to calculate the DII. Additionally, semen and blood samples were collected from each participant for semen analysis and CRP-level assessment. Statistical analyses were performed to explore the association between DII and CRP levels with sperm quality. The correlation between DII and serum/semen CRP, besides assessing nutrients in each DII quartile group, was also explored. Results: A significant difference was observed between different DII quartiles considering sperm motility (p = 0.006) and morphology (p = 0.014). Post hoc study revealed a significant difference between the 1st and 2nd quartiles and the 1st and 4th quartiles of DII regarding sperm motility (p = 0.011, and 0.017 respectively) and a significant difference between the 1st and 2nd quartiles of DII considering sperm morphology (p = 0.009). A statistically significant inverse correlation was also observed between DII and sperm motility (p = 0.017). Carbohydrates and β-carotenes were significantly different between the 4 DII quartiles (p = 0.043 and p = 0.026, respectively). Finally, no significant correlation was observed between DII and CRP levels in blood and semen (p > 0.05). Conclusion: The findings suggested a notable correlation between DII and semen quality; however, no significant association were observed between DII and CRP levels in blood and semen. Key words: Infertility, C-reactive protein, CRP, Inflammation, Sperm

Design and construction of the pressure swirl nozzle and experimental investigation of spray characteristics

This paper focuses on the structure and performance of the pressure swirl nozzle and the study of liquid atomization. In this study, the atomizer has been designed and some experiments have been performed on it. Since image processing is an efficient method for measuring the size of the droplet and since it considerably reduces the total measuring time and eliminates the subjective observer’s error in sizing and counting spray drops, a digital camera has been used for capturing images and image processing has been done by the MATLAB software. The results show that by increasing the atomization air pressure, the spray angle increases and the droplet’s size decreases. It is concluded that the spray angle is a function of the atomization air pressure and orifice diameter. Moreover, when the distance from the spray centre line increases, the droplet’s average velocity decreases

The Relationship between Knowledge Transfer and Competitiveness in “SMES” with Emphasis on Absorptive Capacity and Combinative Capabilities

In order to improve SMES’ competitiveness, introduction of Knowledge into all aspects of production process and management levels is essential. The question is how the knowledge can be transfer into firms? The purpose of this study is to examine the role of knowledge transfer in Firm’s competitiveness. Firms’ need to manage resources flow effectively to be able to survive and to grow in competitive business environment. How can they do this? Over the last decade, the knowledge- based view has rapidly seized a prominent role in strategy research. The knowledge – based view explains that tacit knowledge is the critical component of the value that a firm adds to input , and that a firm’s ability to transfer this tacit knowledge is the essential source of sustained competitive advantage. Firms which have a good absorptive capacity and combinative capabilities are able to compete effectively. Absorptive capacity and combinative capability are main aspect of knowledge - transfer which has captured the attention of numerous studies in recent years. Large firms have possibilities to invest a large amount of money into R&D and to monopolize the knowledge which they have explored and then to exploit it, but the questions are: What about SMES? Are they able to explore and to exploit new knowledge? What are the advantages of K-T in SMES’ competitiveness? With consideration of SMES’ expansion in developed and developing countries, growth and survival of them depend on K-T in these firms and its relationship with firms’ competitiveness. When firms interact with external constituents, be they suppliers or customers, they seek to acquire and/or maintain access to knowledge that otherwise would not efficiently available. Based on the literature review a theoretical model of Small and medium enterprises (SME’S) competitiveness relating to that knowledge transfer is a function of absorptive capacity and combinative capability that characterize the competitiveness. Small and medium enterprises (SMEs) are assumed to play a key role in social and economic development. The theoretical model that was developed in this study predicted that knowledge transfer is a function of absorptive capacity and combinative capability that characterize the SMEs’ competitiveness. Absorptive capacity refers to the capability to understand and use new knowledge. Results from this study indicate that two dimensions of absorptive capacity, available complementary knowledge and prior related experience, are both important antecedents of knowledge transfer. Combinative capability refers to a firm’s capacity to combine and recombine existing knowledge. The theoretical model predicted that this capacity is a function of the opportunity, motivation, and ability to share knowledge. Key words: Competitiveness; Firm; Tacit; Strategy; Absorptive; Combinative; Knowledge; SMES; Capability; Capacity; Motivatio