Wake-promoting agents; insights into clinical use and molecular perspectives

Wake-Promoting Agents [WPAs] such as amphetamine-like stimulants or modafinil, armodafinil, methyl phenidate, caffeine and nicotine reinforce the level of vigilance through an stimulated release of neurotransmitters implicated in the arousal threshold maintenance, hence shift the drive from the sleep-promoting to wake-promoting system. The modulatory effects of WPAs on cortical activation pathways give rise to enhanced vigilance. For example, cholinergic neurons of the basal forebrain and the adenosine receptors on these neurons are agonized and antagonized by nicotine and caffeine, respectively. Caffeine similarly antagonizes adenosine receptors on the GABAergic neurons and intensifies the inhibitory drive in preoptic/anterior hypothalamus which involve in sleep induction. Modafinil however exerts its wake-promoting effects through stimulating the tuberomammillary nucleus and the hypocretinergic neurons which activate the ascending reticular activating system. Although many neutransmitter systems such as dopamine are thought to be involved upon the effects of WPAs, the empirical evidence to explain the exact mechanisms need to gain strength

Combined application of sub-toxic level of silver nanoparticles with low powers of 2450 MHz microwave radiation lead to kill Escherichia coli in a short time

Electromagnetic radiations which have lethal effects on the living cells are currently also considered as a disinfective physical agent. In this investigation, silver nanoparticles were applied to enhance the lethal action of low powers [100 and 180 W] of 2450 MHZ electromagnetic radiation especially against Escherichia coli ATCC 8739. Silver nanoparticles were biologically prepared and used for next experiments. Sterile normal saline solution was prepared and supplemented by silver nanoparticles to reach the sub-inhibitory concentration [6.25microg/mL]. Such diluted silver colloid as well as free-silver nanoparticles solution was inoculated along with test microorganisms, particularly E. coli. These suspensions were separately treated by 2450 MHz electromagnetic radiation for different time intervals in a microwave oven operated at low powers [100 W and 180 W]. The viable counts of bacteria before and after each radiation time were determined by colony-forming unit [CFU] method. Results showed that the addition of silver nanoparticles significantly decreased the required radiation time to kill vegetative forms of microorganisms. However, these nanoparticles had no combined effect with low power electromagnetic radiation when used against Bacillus subtilis spores. The cumulative effect of silver nanoparticles and low powers electromagnetic radiation may be useful in medical centers to reduce contamination in polluted derange and liquid wastes materials and some devices

Isolation and characterization of a fungus for extracellular synthesis of small selenium nanoparticles

The use of biogenic selenium nanoparticles for various purposes is going to be an issue of considerable importance; thus, appropriate simple methods should be developed and tested for the synthesis and recovery of these nanoparticles. In this study, a fungus was isolated from a soil sample, identified as Aspergillus terreus and used for extracellular synthesis of selenium nanoparticles [Se NPs]. UV-Vis spectroscopy and energy dispersive X-ray spectrum studies were carried out to confirm Se NPs formation within 60 min. Dynamic light scattering and scan electron microscopic methods were also used to characterize both size and shapes of the Se NPs. The results show that spherical particles with average size of 47 nm were formed by adding a culture supernatant of A. terreus to selenium ions solution. This approach appears to be an easy and appropriate method for extracellular synthesis of small Se NPs. Extracellular synthesis of small Se NPs has not been reported yet