Effects of extremely low frequency electromagnetic fields during foetal life on adulthood learning in male rat

زمینه و هدف: صنعتی شدن، محیط ما را در معرض میدان های الکترومغناطیسیی قرار داده است که حفاظت در مقابل آنها مشکل به نظر می رسد. در این مطالعه تاثیر امواج الکترومغناطیسی با فرکانس پایین در دوران جنینی بر میزان یادگیری موش صحرایی در زمان بلوغ بررسی شد. روش بررسی: در این مطالعه تجربی، 48 سر موش صحرایی حامله نژاد اسپراگ داولی به 6 گروه 8 تایی شامل گروه کنترل، شاهد و گروه های با فرکانس 5 یا 25 هرتز و شدتهای 50 یا 500 µT تقسیم شدند. مدت زمان تابش 4 ساعت در روز، از 8 تا 12 صبح به صورت مداوم از اولین روز حاملگی تا روز پانزدهم حاملگی بود. پس از زایمان شاخص های یادگیری، وزن بدن، وزن مغز، حجم مغز، نسبت وزن مغز به وزن بدن و چگالی مغز روی فرزندان نر دو ماهه آنها بررسی شد. یادگیری با کمک جعبه شاتل (Shuttle box) به روش یادگیری اجتنابی فعال یک طرفه آزمایش شد و تعداد پاسخ های شرطی و دوره تاخیر پاسخ ها در گروه های مختلف، به کمک آزمون آماری کروسکال والیس مورد تجزیه و تحلیل قرار گرفت. یافته ها: بررسی آماری نتایج نشان داد که فرکانس 25 هرتز و شدت 50 میکروتسلا باعث بهبود یادگیری، کاهش وزن بدن و افزایش نسبت وزن مغز به وزن بدن می شود (05/0

Investigation of Horizontal Axis Wind Tower Installation on Existing Offshore Platforms

Jackets are the most common offshore structures used to extract oil and natural gas in relative low water depth specially, in Adriatic Sea. Most of them have been built in the last 50 years. When the offshore resources run out, these structures must be displaced to another area containing underground resources or removed in the case of reaching to the design life. However, another solution can be investigated: changing the future working life of these platforms by introducing renewable energy and converting them into offshore wind towers. This thesis intends to examine the possibility of changing existing offshore structures used for gas extraction to horizontal axis wind turbine

Different Effects of Testosterone on Acute and Chronic Pain in Gonadectomized Male Rats

ABSTRACT: Introduction & Objective: Nociception and behavioral responses to noxious stimuli are different in males and females. It seems that these differences are due to the effects of sex hormones on the pain mechanisms. The aim of the current study was to evaluate the effect of testosterone administration on nociception by formalin test in gonadectomized rats. Material & Methods: In this study 32 male wistar rats were divided into four groups (n=8) the control rats without receiving any drug or surgical operation, the sham – operated animals with surgical stress, the gonadectomized rats receiving 0.5 ml vehicle (olive oil ) i.p., and the gonadectomized rats receiving testosterone enantate (6 mg/100 gr body weight in 0.5 ml vehicle i.p.). On the sixth day after gonadectomy operation, formalin test was done in all rats. Pain scores in formalin test were statistically analyzed by SPSS and ANOVA. Results: The results showed that testosterone caused an increase in pain score in acute phase of formalin test in gonadectomized rats compared with sham-operated group (p<0.001). However, pain score in chronic phase was significantly reduced in testosterone received rats (p<0.001). Conclusion: It can be concluded that testosterone increases nociception in acute phase of formalin test in gonadectomized rats. On the other hand, testosterone relieved pain during chronic phase. Anti-nociceptive effects of testosterone in chronic phase may be through central nervous system by interacting with endogenous pain modulatory system