An investigation into the effect of audit quality on accounting conservatism in companies listed in Tehran stock exchange

The present study sought to investigate the effect of audit quality on accounting conservatism in Iranian capital market. In this study, given the hypotheses and theoretical foundations of the study, three hypotheses were formulated and the effect of each of the factors of industry-specialist auditor, auditor rank, and auditor tenure was examined on accounting conservatism of companies. The period for investigation was from 2009 to 2013. Its population was determined as all companies listed in Tehran Stock Exchange and the statistical sample of the study included 100 companies. The data required for this study were extracted from website of Tehran Stock Exchange and after collecting events through available resources and entering data in Excel software; its functions were used to calculate the variables of the study. Then, the results from measuring variables were entered into Eviews software for statistical calculations and the relationship between variables were evaluated using this software. The results of the study showed that there is a positive relationship between accounting conservatism and auditing attributes such as auditor rank and auditor tenure. Also, the obtained results indicated that there is no significant relationship between accounting conservatism and customer industry-specialist auditor

A New Formula for Confirmation of Proper Endotracheal Tube Placement with Ultrasonography

Background Endotracheal intubation is an important procedure in critical care and emergency medicine settings. Optimal depth of the tube placement has been a serious concern because of several complications associated with its malposition. Objective: The aim of the current study was to find a new formula to estimate the proper endotracheal tube depth when using ultrasonography or lighted stylet device in order to increase the accuracy of determining Endotracheal tube (ETT) depth and decrease the side effects of ETT misplacement. Method: Patients older than 18 years of age admitted to Imam emergency department who needed tracheal intubation were included. Tube’s length at the angle of the mouth while the tube passed the suprasternal notch, ETT depth after insertion and the distance from ETT’s tip to carina were recorded. Ultrasonography and portable chest x-ray were used as tools for measuring these lengths. Results: A total number of 91 patients including 55 men and 36 women were eligible for inclusion in the study. Not placing the tube at proper depth was considered as failure of intubation. This failure rate was 9.9% in the standard method which would have been 1.1% if our proposed formula was used. Conclusion: The findings of this study suggest that the use of this new formula may help in predicting the proper intubation tube placement. Further studies are warranted to confirm these findings

Chiral Structure of F-actin Bundle Formed by Multivalent Counterions?

The mechanism of multivalent counterion-induced bundle formation by filamentous actin (F-actin) is studied using a coarse-grained model and molecular dynamics simulation. Real diameter size, helically ordered charge distribution and twist rigidity of F-actin are taken into account in our model. The attraction between parallel F-actins induced by multivalent counterions is studied in detail and it is found that the maximum attraction occurs between their closest charged domains. The model F-actins aggregate due to the like-charge attraction and form closely packed bundles. Counterions are mostly distributed in the narrowest gaps between neighboring F-actins inside the bundles and the channels between three adjacent F-actins correspond to low density of the counterions. Density of the counterions varies periodically with a wave length comparable to the separation between consecutive G-actin monomers along the actin polymers. Long-lived defects in the hexagonal order of F-actins in the bundles are observed that their number increases with increasing the bundles size. Combination of electrostatic interactions and twist rigidity has been found not to change the symmetry of F-actin helical conformation from the native 13/6 symmetry. Calculation of zero-temperature energy of hexagonally ordered model F-actins with the charge of the counterions distributed as columns of charge domains representing counterion charge density waves has shown that helical symmetries commensurate with the hexagonal lattice correspond to local minima of the energy of the system. The global minimum of energy corresponds to 24/11 symmetry with the columns of charge domains arranged in the narrowest gaps between the neighboring F-actins.Comment: 9 pages, 10 figures, Published online in Soft Matter journal: http://pubs.rsc.org/en/content/articlelanding/2012/sm/c2sm07104

MicroRNA-mediated regulation of Nrf2 signaling pathway: Implications in disease therapy and protection against oxidative stress

MicroRNAs (miRs) are small non-coding pieces of RNA that are involved in a variety of physiologic processes such as apoptosis, cell proliferation, cell differentiation, cell cycle and cell survival. These multifunctional nucleotides are also capable of preventing oxidative damages by modulating antioxidant defense systems in a variety of milieu, such as in diabetes. Although the exact molecular mechanisms by which miRs modulate the antioxidant defense elements are unclear, some evidence suggests that they may exert these effects via nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway. This intracellular mechanism is crucial in the maintenance of the physiologic redox balance by regulating the expression and activity of various cellular antioxidative defense elements and thereby plays a pivotal role in the development of oxidative stress. Any impairment in the Nrf2 signaling pathway may result in oxidative damage-dependent complications such as various diabetic complications, neurological disorders and cancer. In the current review, we discuss the modulatory effects of miRs on the Nrf2 signaling pathway, which can potentially be novel therapeutic targets