Simultaneous recording of mouse retinal ganglion cells during epiretinal or subretinal stimulation

We compared response patterns and electrical receptive fields (ERF) of retinal ganglion cells (RGCs) during epiretinal and subretinal electrical stimulation of isolated mouse retina. Retinas were stimulated with an array of 3200 independently controllable electrodes. Four response patterns were observed: a burst of activity immediately after stimulation (Type I cells, Vision Research (2008), 48, 1562–1568), delayed bursts beginning \u3e25 ms after stimulation (Type II), a combination of both (Type III), and inhibition of ongoing spike activity. Type I responses were produced more often by epiretinal than subretinal stimulation whereas delayed and inhibitory responses were evoked more frequently by subretinal stimulation. Response latencies were significantly shorter with epiretinal than subretinal stimulation. These data suggest that subretinal stimulation is more effective at activating intraretinal circuits than epiretinal stimulation. There was no significant difference in charge threshold between subretinal and epiretinal configurations. ERFs were defined by the stimulating array surface area that successfully stimulated spikes in an RGC. ERFs were complex in shape, similar to receptive fields mapped with light. ERF areas were significantly smaller with subretinal than epiretinal stimulation. This may reflect the greater distance between stimulating electrodes and RGCs in the subretinal configuration. ERFs for immediate and delayed responses mapped within the same Type III cells differed in shape and size, consistent with different sites and mechanisms for generating these two response types

Venture Capital and Business Angels and the Creation of Innovative Firms in Poland

The article also points out that conditions fostering further development of the described types of entrepreneurship and innovation financing and a dynamic environment generating innovative capacity should be created.W artykule zasygnalizowano również potrzebę kreowania uwarunkowań sprzyjających rozwojowi opisanych form finansowania przedsiębiorczości, innowacyjności i dynamicznego otoczenia generującego zdolności innowacyjne

Maximization of propylene in an industrial FCC unit

YesThe FCC riser cracks gas oil into useful fuels such as gasoline, diesel and some lighter products such as ethylene and propylene, which are major building blocks for the polyethylene and polypropylene production. The production objective of the riser is usually the maximization of gasoline and diesel, but it can also be to maximize propylene. The optimization and parameter estimation of a six-lumped catalytic cracking reaction of gas oil in FCC is carried out to maximize the yield of propylene using an optimisation framework developed in gPROMS software 5.0 by optimizing mass flow rates and temperatures of catalyst and gas oil. The optimal values of 290.8 kg/s mass flow rate of catalyst and 53.4 kg/s mass flow rate of gas oil were obtained as propylene yield is maximized to give 8.95 wt%. When compared with the base case simulation value of 4.59 wt% propylene yield, the maximized propylene yield is increased by 95%

Effect of the Aqueous Extract of \u3cem\u3eChrysanthellum indicum\u3c/em\u3e on Calcium Mobilization and Activation of Rat Portal Vein

The effects of the aqueous extract of Chrysanthellum indicum (CI) on calcium activation and mobilization were studied using the rat portal vein. The extract caused a concentration-dependent contraction of the portal vein. KCl (80 mM), norepinephrine (NA, 10−6 M) and CI (4 mg/ml) evoked sustained contraction of the portal vein. In Ca-free medium (with EGTA) the contractions evoked by these agents were reduced significantly. The times-to-peak of KCl, NA and CI were similar -in normal PSS, but in Ca-free medium the times-to-peak for KCl and CI were greatly increased. The contractions induced by CI were not inhibited by chlorpropamide and prazosin, but were blocked by verapamil. The data obtained suggest that the aqueous extract of CI utilizes extracellular calcium pools to bring about contractile response and this effect might be mediated through the activation of potential-sensitive channels