One of the main concerns of investors in financial market is reduction of risk and achieving desired return. One of the ways that reduce risk, is creating portfolio; but due to market changes, the optimal portfolio will not be stable and it is necessary to be control and rebalancing. Generally, investors in financial market are divided into two categories: real investors and legal investors. The volume of real investors' capital is little and is called small investors, too. Portfolio selection and rebalancing for small investors need attention to their criteria and limitations that are not considered in the classic financial models such as Markowitz’ s model. These criteria are transaction cost, dividend, systematic risk and transaction units. In this study, a multi-objective and comprehensive model are provided that addresses the goals and limitations of small investors. For this purpose, the lexicographic goal programming is used and a mixed integer programming model is provided. Finally, the model is solved with actual data and the results are analyzed.

Introduction: Skeletal muscles account for about 40% of the total body weight. Every year, hundreds of people lose at least part of their muscle tissue due to illness, war, and accidents. This can lead to disruption of activities such as breathing, movement, and social life. To this end, various therapeutic strategies such as medication therapy, cell therapy and tissue transplantation have been used or studied in muscle regeneration. However, there is no effective and well-defined clinical approach for treatment of muscle injuries and the severity of muscle injuries increase with age in most cases. Therefore, investigation for finding new and effective clinical approach for muscle regeneration is one of the most important issues in basic and clinical researches. Tissue engineering is considered as one of the promising and newest approach for skeletal muscle tissue regeneration and provides an appropriate model for personalized medicine and basic researches that can be used in personalized medicine and basic research. Besides biomaterials and cells, inducing factors are another element of tissue engineering. These factors influence epigenetic mechanisms and signaling pathway, thereby inducing proliferation, differentiation, and migration of cells used in muscle tissue engineering, and accelerates muscle formation in vitro. Recently, small molecules have been used as alternatives to growth factors or along with other inducing factors in muscle tissue engineering. Since they do not induce an immune reaction, penetrate easily to the cells and have a specific molecular target, therefore they have attracted much attention as the cost-effective inducing factors in tissue engineering. Conclusion: Taken together, the effective small molecules in muscle tissue engineering can be used with different biomaterial conditions (e. g. hydrogel, decellularized tissue, and synthetic scaffolds) in both in vivo and in vitro, resulting to production of cost effective and highly efficient engineered muscle tissues that help to achieve therapeutical goals of muscle tissue engineering. Herein, we describe tissue engineering and review the small molecules used in skeletal muscle tissue engineering.

In recent years, much more attentions have been focused on siRNA-based gene therapy. This approach is based on PTGS (Post-transcriptional gene silencing). Due to some defects in viral vectors, non-viral vectors have been used to deliver nucleic acids into target cells. Although, transfection efficiency in non-viral vectors is less than viral ones, but safety of non-viral vectors is much more. Characteristic features of siRNA, such as high compatibility, application in low doses and its versatility make it suitable in the gene therapy field. However, some challenges, such as stimulating immune system and Off-target silencing will be remain. In this review article, we express bottlenecks existing in siRNA delivery into target cells. According to the information, with further development of siRNA delivery in the future, it could be a promising approach in treatment for a variety of genetic diseases.

This is always probable by agency theory that managers of the corporation do not decide based on shareholders' profit, so they tried to prepare a base of opaque reporting and absolutely the crash of the price of stock in order to receive good news in the future. As opposed to that, institutional actionaries are being used by contexts of corporate govermance by emphasizing on them as controlling equips to contrast with opportunistic gravitation and coalesence of efficient contract, to emphasize on the role of institutional investors in guidance machanism of corporation and their potential ability in affecting on methods and politics which are being used by managers. As a result, it is necessary to study about the role of institutional investors in sudden crash of the stock price. Therefore, this research has checked the relation between institutional investors and crash of stock price by exploiting two hypotheses of efficient supervision and revenue convergence and also categorizing institutional investors into two groups of transient and dedicated institutional investors, it has also used the information of 152 accepted companies in Tehran stock market. Findings of the research show that there is a negative and meaningful relation between dedicated institutional investors and crash of stock price. So, there is no relationship between transient institutional investors and the crash of stock price; this matter is pointing to differentiation of transient and dedicated institutional investors and also emphasizing on dedicated institutional investors as efficient controlling equips on pillar of leading the organization and contrast with sudden crash of stock price.

In analyzing mutual funds’ performance, the funds’ return is typically deemed as a performance measure and this measure is not necessarily discriminated by the virtually investors’ realized return. This is despite the fact that depending on the investors’ timing strategy and the amount they decide to invest, the actually realized return may likely be different with the announced return by the fund, which is normally based on the buy and hold strategy. In the present study, we are going to answer how investors’ timing decisions in mutual funds may affect their returns and eventually their behavior. To do so, we have exploited the registered mutual funds’ cash flow turn over over 1390 to 1395 (2011-2016) and finally come up with conclusion that inefficient market timing by mutual funds investors’ have culminated in diminishing 2. 2 % their monthly return (30 % annually). This considerable negative effect can significantly alleviate the investors realized return even in outperforming mutual funds.

With respect to financial decisions in daily life of investors, in this research we assess the mental state of investors on their risk taking behavior in Tehran stock exchange. Risk taking is the degree of encouragement investors has in order to take innovation and do extraordinary jobs. Mental state is composed of sustainable emotions with external expression in different degrees and continuity for kinds of investors. All Tehran stock exchange investors were among the study and 386 samples were selected. For mental state and risk taking behavior data gathered on the basis of PANAS and risk taking standard questioners in turn. Hypothesis tested by structural equation modeling with partial least square approach. Results show risk taking is positively affected by high positive affection and low negative affection besides negatively affected by low positive affection and high negative affection. High positive affection has the highest impact and low positive affection has the lowest impact on risk taking behavior.

Studies show religion is effective factor in forming social mood. Therefore, the impact of religion on behavioral bias affected by social mood can be studied. This study is an expost facto research that Using observed data tests possibility of herd behavior in religious months, consist of Muharram, Ramadan, and Zul-Hijjah, in Iranian capital market. After studying 1206 days of Daily trade in Tehran Stock Exchange during 1989-1993 (Solar Hijri-Iranian calendar), results show possibility of herd behavior in religious months more than other months of the year. Between religious month, Ramadan has the greatest impact of forming herd behavior. Also, the theories point out market performance and trading volume affect herd behavior. Accordingly, using robustness tests, this study investigates possibility of herd behavior affected by market performance and trading volume. However, there was no certain pattern. These results make contributions to the literature on the effects of social norm studies on markets, herding in stock market, and Islamic finance studies in particular.

The Purpose of This Study was to Identify the Effect of Psychological Bias on Financial investors' Satisfaction in Tehran Stock Exchange. In this field of research, in order to collect data field method and standard questionnaire were used. The validity of questionnaire was checked by experts. In the next step, the reliability of the questionnaire was investigated using Cronbach's alpha coefficient. The results confirm that the questionnaire has the necessary reliability. The statistical population of this research is real investors in Tehran Stock Exchange. Considering that the number of the statistical population is unlimited, the desired sample size of 384 people was randomly selected using Cochran's formula and investigated. In order to Investigate the Relationship Btween the Variables of Research, Structural Equation Modeling Technique and LISREL Software have been used. Good Fitting Indicators Such as RMSEA, GFI, and AGFI Indicate Good fit of the Model and the Usability of the Results. The Results show That the Effect of Excessive Self-confidence, Reliance on Financial Experts, Tendency to Classify Money, Tendency to Budgeting, Tendency to adapt, Social Responsibility, Reliance on Spouse and Self-control on Positive Financial Satisfaction and Meaningful.

This study examines whether sophisticated investors implement traditional accruals strategy and percent accruals strategy. Moreover we compare the amount of excess return and risk adjusted return of accruals strategy sophisticated investors and of those who are neutral to accruals strategy. For this purpose, we collect quarterly data of 950 observation of investment companies listed in Tehran Stock Exchange for the years 2011-2018. The hypotheses were tested using one sample t test. The results show that sophisticated investors do not implement accruals strategy. But implementation of accruals strategy by a subsample of sophisticated investors was verified. The results show traditional accruals strategy sophisticated investors do not earn excess return and risk adjusted return in compare with those who are neutral to traditional accruals strategy regardless of return measures. But there is some evidence that percent accruals strategy sophisticated investors earn excess return and risk adjusted return in compare with those who are neutral to percent accruals strategy.