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Chiral metamaterials of the terahertz range are formed by means of rolling of strained nanofilms. Structural elements of these metamaterials are metal-semiconductor microhelices. Resonant optical activity of new metamaterials in the terahertz range is demonstrated. Arrays of model wire helices are formed and tested in the microwave range. [ABSTRACT FROM AUTHOR]

Introduction: recent studies in the field of infertility have showed the implications of immunologic substances in infertility and prenatal problems. These substances, including antisperm antibody (ASA), are the result of immune system reactions of male or his partner against sperms. Studies mentioned different mechanisms for production of these antibodies such as destruction of sperm-blood barrier in male or female body. It seems to be that these antibodies block sperms and decrease their motility and fertility potency. Dorr et al showed these antibodies are specific for each person. This paper aims to review current treatments in this field. If antisperm antibodies are causes of infertilities the costs of current infertility treatments can be hugely reduced. Materials and Methods: This study was written using relevant articles published during the period 2004-2013 in PubMed. Keywords including anti-sperm antibody abd infertility were used to find articles. Results: Studies indicated controversies regarding the implication of these antibodies. Zini et al in 2011 evaluated the effect of ASA on sperms in IVF and ICSI in vitro environment in Mc. Hill University. They reported no significant correlation between ASA level and spermatic motility factors, morphology and their fertility potency. Another study shows the same result in 2007. In 2010, Check examined the ASA effects on human body and reported decreasing fertility rate in sperms covered with ASA to one third. In 2008, Wlilliams found murine FA-1 antigen and YLP(12) in infertile women who were the cause of infertility. He suggested to produce a vaccine against these agents. Conclusion: Given the probable role of ASA in infertility, we could use simpler, cheaper methods to control this antibody in infertile couples instead of costly methods like IVF or IICSI. This method can even be used as a reliable contraceptive. Still, the results are shrouded in controversy and larger sample sizes are required. [ABSTRACT FROM AUTHOR]

Introduction: The growth and development of germ cells is a process which starts in fetus and will be completed in puberty. Spermatogonial stem cells in mammals, will maintain the capability of spermatogenesis during life time. These undifferentiated stem cells have the ability (potency) to be self-renewed and differentiate into mature sperms. These abilities are regulated by a series of mechanisms, including gene expression and also extrinsic gene signals. Various therapeutic factors or toxic agents (which come from the environment) can harm human testis because of its susceptibility to different damages. Materials and Methods: This study was performed based on recent related articles published in PubMed database. Keywords including stem cell, spermatogonial stem cells and infertility were used to obtain articles. Results and Conclusion: There is a possibility for the transplantation and transfer of spermatogonial stem cell in order to preserve fertility in patients treated with radiotherapy or chemotherapy. According to the studies, the development and preservation of human fertility with germ cell transplantation is not certainly proved, but it has been argued that it could be appropriate (suitable) for young patients suffering from cancer with no other way of preserving fertility. Today, this method accounts as an important research tool in animal laboratory and its clinical applications in experimental works are considerable; however, many different features of this method should be determined and optimized before it is clinically used for men. [ABSTRACT FROM AUTHOR]