فهرست مطالب وحید علی زاده

The present work describes the physicochemical and antimicrobial properties of active films developed by incorporating different concentrations (0.5, 1, and 2% v/v) of Satureja hortensis essential oil (SEO) and 3% (w/w) nanoclay into a chitosan- montmorillonite nanocomposite film. The tensile strength (TS) of the films significantly decreased and elongation at break (EAB) increased with the incorporation of SEO. The control film exhibited the lowest water vapor permeability. In addition, decreases in water solubility (WS) and transparency were observed with increasing the concentration of SEO. Thermogravimetric analysis (TGA) indicated that films incorporated with SEO exhibited a higher degradation temperature compared with the control. The structural properties and morphology of the nanocomposite films were examined by X-ray diffractometry (XRD) and Scanning electron microscopy (SEM). SEO-incorporated films were more effective against gram positive bacteria (Staphylococcus aureus and Bacillus cereus) than gram negative ones (Salmonella typhimurium and Escherichia coli). The results suggested that SEO, as a natural antibacterial agent, has the potential to be applied in antimicrobial biodegradable films.

In this study, biodegradable soluble soybean polysaccharide based films containing Satureja hortensis essential oil at concentrations of 0%, 1%, 2% and 3% (v/v) were developed to examine their physical, mechanical, total phenol, antioxidant and antimicrobial properties. At the level of 3% of essential oil, soluble soybean polysaccharide films showed the lowest water solubility (47.26%), tensile strength values (9.43 MPa) and water vapor permeability (1.60 g/m.s.Pa × 10-10) and the highest values for thickness (0.089 mm) and strain-to-break (35.40%). Antioxidant and antibacterial characteristics significantly increased by the inclusion of essential oil. Our observation showed that essential oil containing films at a level of 3% had the highest antioxidant activity (73.31%). The films exhibited highest inhibition against gram positive bacteria than gram negative bacteria. The results of the present work showed that Satureja hortensis essential oil as a natural antibacterial and antioxidant agent has the great potential to make biodegradable films.

The environmental effect of synthetic plastic wastes is of increasing global concern. There is an urgent need to develop and apply renewable biopolymer materials. Development of edible and biodegradable films can help solving the waste disposal problem by partially replacing synthetic plastics (Martins et al., 2012). Chitosan; a linear polysaccharide composed of (1, 4)-linked 2-amino-deoxy-b-d-glucan, is a deacetylated (to varying degrees) product of chitin, which is the second most abundant polymer found in nature after cellulose. It has been proved to be biodegradable, biofunctional, biocompatible, nontoxic and have strong antifungal and antimicrobial properties (Aider, 2010). Thus, this work was undertaken to investigate the physical, optical, barrier, mechanical, microstructural, and antimicrobial properties of chitosan films incorporated with PEO, to examine its potential applications as a packaging material.
The films were prepared according to the solvent casting technique reported by (Abdollahi et al., 2012) with some modifications. Tensile strenght (TS) and elongation at break (E) of the films were measured with texture analyzer according to Barzegar et al. (2014) method. Equilibrated film strips (at 53% RH for 48 h) were fixed between the grips with an initial separation of 50 mm and the cross-head speed was set at 50 mm/min. TS was calculated by dividing the maximum force by the initial area of the film and E% was calculated through dividing the extension at the moment of specimen rupture by the initial gauge length and multiplying by 100. The WVP of the films was determined at according to the Shojaee-Aliabadi et al. (2013). The test cups containing anhydrous calcium chloride (0% RH) were sealed by the test films, then were placed inside a desiccator containing sodium-chloride-saturated solution (75% RH). Weight gain of the cups along time were recorded periodically and plotted as a function of time. Antimicrobial properties of the films were assessed using the disc-diffusion method according to Dashipour et al. (2015). Four gram-positive or gram-negative bacteria, including B. cereus, S. aureus, E. coli and S. typhimurium were used for testing.
The influence of PEO incorporation on thickness, TS, EAB, WVP and water solubility of films can be seen in Table 1. The incorporation of PEO into the film-forming dispersion led to an increase in the thickness of the films, which varied between 0.131 mm and 0.185 mm. It could be due to the entrapment of PEO micro droplets by the polymer matrix (Dashipour et al. 2015). By increasing PEO concentration from 0.5 to 2 % in the film solutions, WS decreased markedly from 22.46 to 16.15 (P The results obtained in this study showed that the chitosan films incorporated with PEO has a good potential to being empolyed as an active film to preserve food products. Addition of PEO decreased water solubility and tensile strength, while increased the thickness, WVP and percent elongation of the films. Overall, this study demonstrates that PEO-containing films present a good potential for their application in the food industry.

In recent years using fresh foods that have undergone minimal processing, has become widespread. The use of biodegradable packaging is a new method for preserving of these products. The current research investigated the effect of different contents (1, 3, and 5 wt %) of montmorillonite (MMT) nanoclay on the physical properties of psyllium seed hydrocolloid nanocomposites. With the addition of up to 5% MMT, the tensile strength of the nanocomposite films increased from 11.60 to 17.08 MPa and the percent of elongation decreased from 30.42% to 19.02%. At the level of 5% MMT, the nanocomposite films showed the 35.04% reduction in the water vapor permeability in comparison to pure psyllium film. In addition, water solubility decreased when MMT was incorporated into the nanocomposite films. Scanning electron microscopy images indicates a good distribution for nanoclay particles in the biopolymer matrix. This
study revealed that the psyllium seed hydrocolloid had a good potential to be used in producing nanocomposite film with desirable characteristics.

To restrict undesirable investor’s perception and create awareness about future prospects، companies may make voluntary disclosure. Providing voluntary information about identification، measurement and disclosure of accounting numbers in financial statements lead to attract investors and effectively help to improve the company''s financial position and managerial popularity. The aim of this study is to investigate the relation between voluntary disclosure and performance of firms listed in Tehran Stock Exchange. Based on 80 companies information during 2002 to 2011، the results show that there is no significant relation between voluntary disclosure and return on assets and return on equity; but there is a significant positive relation between voluntary disclosure and efficiency scores calculated by Data Envelopment Analysis as a comprehensive measure of performance.

Managers venture to voluntary disclosure to inform investors about firms’ future point of views, goals and strategies. Financial and non-financial voluntary information reduce information asymmetry, increase stock liquidity and improve financial stability. In this research the relation of voluntary disclosure level and information asymmetry of listed companies of Tehran Stock Exchange is investigated. Botosan (1997) check list which has been adjusted by kashanipour and et al. (2009) was utilized to measure voluntary disclosure level. The check list consists of 71 indices through six section of background information, the summery of historical results, Key Non-Financial Statistics, Segments Information, Projected Information and Management Discussion and Analysis. Moreover, information asymmetry variable is measured by using Venkatash and Chiang (1986) model. To test research hypotheses multivariate regression with panel data is utilized. The results show that there is no significant relation between voluntary disclosure level and information asymmetry of 122 listed companies of Tehran Stock Exchange during 2003-2011.

Aims and Propofol is one of the newest and the most common drugs in anesthesia and intensive care unit which is used to produce sedative effects. One of its complications is the pain produced at the time of injection. The aim of this study is to compare the pain of Propofol injection with two techniques: Propofol mixed with lidocaine and Propofol injection after lidocaine. This study is a randomized double-blind clinical trial, in which 172 patients undergoing elective surgery with ASA class one and two were enrolled. Three groups of patients had injections as follows: In the first group 40 mg Propofol mixed with 2% lidocaine, in the second one purified one percent propofol, and in the third group Propofol following injection of 40 mg lidocaine 2%, were injected. Venous catheter 20 gauge was used in all cases for injection, and pain intensity was measured by VRS (Verbal Rating Scale) criteria. The data were analyzed by SPSS V.18. Pain intensity in the second group (Propofol injection after lidocaine injection) was less than the first group (mixed injection) and there was a statistically significant difference between the two groups (P<0.05). The hemodynamic changes were similar in both groups, and there was no significant difference (P>0. 05). Pre-treatment by injecting 40 mg of lidocaine2% to reduce pain due to Propofol injection is more effective than mixed method of injecting 40 mg of Propofol with lidocaine 2%.

Before placing or cementing a restoration into a cavity preparation, the clinician must decide whether a cavity base, liner or a protective cavity sealer should be placed. While this seems simple, the decision is complicated by an ever-increasing number of products available. In addition, the clinical success of an indirect restorative procedure depends, to a great extent, on the relationship between the restoration and the tooth. The practice of fixed prosthodontics has changed dramatically with the introduction of innovative techniques and materials. Adhesive resin systems are examples of these changes that have led to popularity of bonded ceramics and resin-retained fixed partial dentures. This review was collected with a scientific search in MEDLINE in relation to the following categories: the definition of liners, bases and cements, their clinical applications, mechanical properties, biocompatibility, principles of adhesion, specific types of materials and their use as liners, bases or cements. In addition, the review discusses cementation techniques for different types of restorations, and other relevant clinical information. Tables of products available and their properties are also presented. Although each cement type has been widely investigated, the correct clinical choice between them is not always clear. None of them is suitable to be used for the entire broad range of indirect restorative procedures. Therefore, their proper application requires a thorough understanding and awareness of each material's advantages and disadvantages, taking into account the restorative material, moisture control and preparation design (retentive or adhesive).

Blood transfusion is one of essential and important but dangerous parts of today's medicine in which if appropriate measures have not been done, fatal reactions may occur. Acute hemolytic reactions, febrile reactions, and allergic reactions are among the most important and most prevalent transfusion reactions that happen shortly after its beginning and can lead to considerable mortality and morbidity. The aim of this descriptive study was to investigate the prevalence of acute reactions of blood and its products prepared by Urumia Blood Refinery Center. 3880 blood product units transfused to 1261 patients were studied by convenience sampling method. Various instruments and methods such as sphygmomanometer, thermometer, urine analysis, interview and observation were used for data gathering. Collected data were documented in special forms designed for this purpose. Descriptive statistics were used for data analysis. Among the blood recipients, 604 were female and 657 were male. The most frequent complaints of patients were coldness (22.5%), pruritus (20.1%) and chills (18.1%). The prevalence of acute hemolytic reaction, febrile reaction and allergic reactions were 0.52, 6.2 and 11.1 per 1000 transfusions respectively. In spite of improved blood refinement techniques, acute transfusion reactions can lead to significant morbidity and mortality. Therefore, physicians’, nurses’ and midwives’ meticulous attention to early symptoms and signs of acute reactions to transfusion of blood and its products have an important role in preventing adverse outcomes of this life-saving remedy.