To investigate the determinants of this frequency-scaling, we considered a generic recurrent model of cortex receiving a retinotopically organized external input. Similarly to the in vivo case, our in
computo simulations show that the scaling exponent reflects the correlation level imposed in the input. This systematic dependence was also replicated at the single cell level, by controlling independently, in a parametric way, the strength and the temporal decay of the pairwise correlation between presynaptic inputs. This last model was implemented in vitro by imposing the correlation Selonsertib mw control in artificial presynaptic spike trains through dynamic-clamp techniques. These in vitro manipulations induced a modulation of the scaling exponent, similar to that observed in vivo and predicted in computo. We conclude that the frequency-scaling exponent of the Vm reflects stimulus-driven correlations in the cortical network activity. Therefore, we propose that the scaling exponent could be used to read-out the “”effective” connectivity responsible for the dynamical signature of the population signals measured at different integration levels, from Vm to LFP, EEG and selleck products fMRI.”
“The objectives of this research were to prepare ribavirin niosomes and evaluate the influence of niosomal encapsulation
on drug liver targeting in rats. Ribavirin niosomes were prepared by the thin film hydration method using span 60, cholesterol, and dicetyl phosphate in molar ratios of (1:1:0), (4:2:0), (1:1:0.1), and AC220 (4:2:1). The prepared niosomes were characterized in vitro for vesicle size, drug entrapment, drug release profiles, and vesicular stability at refrigerator temperature. The results indicated that niosomes of the molar ratio (4:2:1) had a significantly (p < 0.05) higher entrapment percentage of ribavirin than the other molar ratios, moreover, they revealed sustained release characteristics as well as longer
release pattern than other niosomal formulations. Accordingly, niosomes of molar ratio (4:2:1) was selected for in vivo liver targeting study. Separately, niosomal ribavirin dispersion and free ribavirin solution were administered as a single dose of 30 mg/kg by intraperitoneal injection into two groups of rats to compare the liver ribavirin concentration. The obtained results show that the niosomal formulation significantly increased ribavirin liver concentration (6-fold) in comparison with ribavirin-free solution. Based on the previous results, the use of niosomes as a drug delivery system for ribavirin has significant liver targeting properties, this is expected to improve the efficacy of low doses of ribavirin and minimize its toxic side-effects at higher doses.”
“Macroporous poly(vinyl alcohol) foam with epichlorohydrin as a crosslinking agent was investigated. The average molecular weight between crosslinks, crosslinking density, and mesh size were determined through the equilibrium swelling theory.