Phase coherent transport in SrTiO3/LaAlO3 interfaces

The two dimensional electron gas formed between the two band insulators SrTiO3 and LaAlO3 exhibits a variety of interesting physical properties which make it an appealing material for use in future spintronics and/or quantum computing devices. For this kind of applications electrons have to retain their phase memory for sufficiently long times or length. Using a mesoscopic size device we were able to extract the phase coherence length, and its temperature variation. We find the dephasing rate to have a power law dependence on temperature. The power depends on the temperature range studied and sheet resistance as expected from dephasing due to strong electron-electron interactions.Comment: Submitted to Phys. Rev

The ovary learns to ovulate

Sensory stimuli from the external environment (e.g. visual and olfactory stimuli, stress) or internal stimuli cause brain nerve fibres to release neurotransmitters (catecholamines, indolamines and cholinergic agents). These neurotransmitters regulate the secretion of gonadotrophin-releasing hormone (GnRH) from neurosecretory cells of the hypothalamus (Kamberi, 1975). It would seem that under the proper steroid environment, catecholamines (dopamine, norepinephrine or epinephrine) and the cholinergic agent acetylcholine exert a stimulatory influence, whereas indolamines (serotonin or its metabolic product, melatonin) have an opposite effect. In turn, GnRH reaches the anterior pituitary via the hypophyseal portal system, and, through the mediation of cAMP [though may be not as an obligatory intermediate (Naor et al., 1975)], controls gonadotrophin secretion (Labrie et al., 1974

Human recombinant follicle stimulating hormone (rFSH) compared to urinary human menopausal gonadotropin (HMG) for ovarian stimulation in assisted reproduction: a literature review and cost evaluation

BACKGROUND: Gonadotropins are protein hormones which are central to the complex endocrine system that regulates normal growth, sexual development, and reproductive function. There is still a lively debate on which type of gonadotropin medication should be used, either human menopausal gonadotropin or recombinant follicle-stimulating hormone. The objective of the study was to perform a systematic review of the recent literature to compare recombinant follicle-stimulating hormone to human menopausal gonadotropin with the aim to assess any differences in terms of efficacy and to provide a cost evaluation based on findings of this systematic review. METHODS: The review was conducted selecting prospective, randomized, controlled trials comparing the two gonadotropin medications from a literature search of several databases. The outcome measure used to evaluate efficacy was the number of oocytes retrieved per cycle. In addition, a cost evaluation was performed based on retrieved efficacy data. RESULTS: The number of oocytes retrieved appeared to be higher for human menopausal gonadotropin in only 2 studies while 10 out of 13 studies showed a higher mean number of oocytes retrieved per cycle for recombinant follicle-stimulating hormone. The results of the cost evaluation provided a similar cost per oocyte for both hormones. CONCLUSIONS: Recombinant follicle-stimulating hormone treatment resulted in a higher oocytes yield per cycle than human menopausal gonadotropin at similar cost per oocyte