Comparison of Serum Level of Some Trace Elements and Vitamin D Between Patients with Premenstrual Syndrome and Normal Controls: A Cross-sectional Study

Background: Premenstrual syndrome (PMS) is a common problem among women and is identified by reversal emotional, psychological, and physical signs during the luteal phase. These signs, however, lower down in the follicular phase. The cause of PMS isn't very well-known up to now control group and many researchers have suggested that mineral compounds and vitamins can inhibit these symptoms. Objective: The objective of this study is to compare the serum level of some trace elements and vitamin D between normal controls and patients with PMS. Materials and Methods: 300 female students (19–21 yr old) from Falavarjan County were randomly selected and asked to complete a standard questionnaire on PMS during three menstruation cycles. The students were divided into two groups: healthy persons (control) and PMS persons, and PMS was determined on the basis of the answers to the questionnaire. Thereafter, the serum concentrations of zinc, iron, calcium, magnesium, potassium, sodium, and Vitamin D3 were measured and compared between the two groups. Results: Our results showed that the PMS prevalence was about 41.5%. The level of vitamin D decreased in both the control and PMS groups, with a significantly lower range of vitamin D (p 0.05) in the PMS group. Other factors had no significant change between the two groups. Conclusion: Vitamin D deficiency was probably one of the most important causes of unpleasant symptoms of PMS between these students. Key words: Premenstrual syndrome, Trace elements, Vitamin D

Islanding Feasibility Considering Reactive Power in the Subtransmission Systems

Nowadays, the penetration of Renewable Energy Sources (RES) in electrical networks is growing significantly. In spite of many problems it introduces, the connection of RES in the subtransmission systems also gives the opportunity of exploiting them for the benefit of the network. In this paper, this is done for islanding conditions and a Genetic Algorithm (GA) based procedure to make a stable islanded operation is proposed. The results are evaluated successfully by tests carried out on a real system

Detection of Islanding Feasibility in Subtransmission Systems

The penetration of Renewable Energy Sources (RES) is increasing in modern power systems. The integration of large amounts of RES is a challenge but the technology provides many tools to exploit them for uses and functions considered, so far, a prerogative of more traditional power plants. For example, since a large amount of RES is installed in HV subtransmission grids, it is possible to exploit them in wanted and unwanted islanding conditions. In this paper, a procedure for evaluating off-line the feasibility of islanded operation and planning it is presented. This procedure defines which generators and loads could remain connected after islanding to balance the real power of the island. For each possible set of islanding events, the set of discrete control actions (opening switches) is determined and communicated to local Substation Automation Systems, to be put in place in case of actual islanding. Results, including dynamic simulation responses, are shown with reference to real power systems