Low plasma volume coincides with sympathetic hyperactivity and reduced baroreflex sensitivity in formerly preeclamptic patients.

Contains fulltext : 50660.pdf (publisher's version ) (Open Access)BACKGROUND: Preeclampsia is associated with enhanced sympathetic activity as well as subnormal plasma volume. Meanwhile, in over 50% of these complicated pregnancies, the subnormal plasma volume has been found to persist for a prolonged period after pregnancy. The objective of this study is to test the hypothesis that in normotensive formerly-preeclamptic women, persistence of a subnormal plasma volume coincides with enhanced sympathetic activity and with it, an altered autonomic control of blood pressure. METHODS: Forty-eight formerly-preeclamptic women participated in this study. After measurement of their plasma volume by iodine 125-albumin indicator dilution, they were subdivided into a group with a normal plasma volume (plasma volume > 48 ml/kg lean body mass) and a group with a subnormal plasma volume (< or = 48 ml/kg lean body mass). We performed spectral analysis on their beat-to-beat blood pressure and heart rate recordings and compared both groups using non-parametric tests. RESULTS: Formerly-preeclamptic women with a subnormal plasma volume had a higher sympathetic activity (P = .001) and a lower baroreflex sensitivity (P = .04) than their counterparts with a normal plasma volume. CONCLUSION: In normotensive formerly-preeclamptic women, a subnormal plasma volume coincides with a higher sympathetic activity in the blood pressure regulation and lower baroreflex sensitivity. Whether these alterations in the autonomic control mechanisms are a cause or effect of the subnormal plasma volume remains to be elucidated

Photon-responsive nanomaterials for solar cells

The global issue of the utmost exhaustion of fossil fuels on earth has driven research towards the development of alternative energy resources to meet the increasing demand for energy required in modern society. Among the different types of renewable sources, solar energy is the largest energy source which is unlimited and clean. Currently solar cells or photovoltaic (PV) technologies that generate electricity by harnessing sunlight is one of the fastest growing power generation sources in the energy sector. In this chapter we review the application of nanomaterials in some types of solar cells including dye-sensitized solar cells, quantum dots solar cells and perovskite solar cells. Semiconductor materials such as TiO2, ZnOx, SnOx, NiOx etc have been widely used as electron or hole transport materials in these type of solar cells. The morphology, shape, size, crystal structure of particles of these materials can significantly influence the device performance. The outlook of the future research direction is provided at the end of the review.</p