Astrocytes Learn to Detect and Signal Deviations From Critical Brain Dynamics.

Astrocytes are nonneuronal brain cells that were recently shown to actively communicate with neurons and are implicated in memory, learning, and regulation of cognitive states. Interestingly, these information processing functions are also closely linked to the brain's ability to self-organize at a critical phase transition. Investigating the mechanistic link between astrocytes and critical brain dynamics remains beyond the reach of cellular experiments, but it becomes increasingly approachable through computational studies. We developed a biologically plausible computational model of astrocytes to analyze how astrocyte calcium waves can respond to changes in underlying network dynamics. Our results suggest that astrocytes detect synaptic activity and signal directional changes in neuronal network dynamics using the frequency of their calcium waves. We show that this function may be facilitated by receptor scaling plasticity by enabling astrocytes to learn the approximate information content of input synaptic activity. This resulted in a computationally simple, information-theoretic model, which we demonstrate replicating the signaling functionality of the biophysical astrocyte model with receptor scaling. Our findings provide several experimentally testable hypotheses that offer insight into the regulatory role of astrocytes in brain information processing.

2D "soap"-assembly of nanoparticles via colloid-induced condensation of mixed Langmuir monolayers of fatty surfactants.

We describe a new type of colloidal 2D gels formed in mixed Langmuir monolayers of stearic acid and octadecylamine on a surface of gold hydrosol. The adsorption of gold nanoparticles on the mixed monolayer led to an increase of interactions between oppositely charged surfactants giving a "soap" of mixed fatty salt. The observed effect is equivalent to a virtual "cooling" of floating monolayer, which undergoes rapid condensation on a surface of aqueous colloid. The consequent shrinking and rearrangement of the monolayer resulted in aggregation of nanoparticles into colloidal 2D "soap"-gels, which represented arrested colloidal phases within nonadsorbing organic medium. When sequentially deposited onto solids by Langmuir-Blodgett technique, the 2D "soap"-gels separated into organic and colloidal phases and gave dendrite-like bilateral organic crystallites coated with gold nanoparticles. The reported colloidal "soap"-assembly can offer a new opportunity to design 2D colloidal systems of widely variable chemistry and structures.

The 'all comer' Coroflex Please drug-eluting stent registry in Europe and Asia - an overall and transcontinental assessment of the 10-month major adverse cardiac events.

BACKGROUND: Randomized trials assess the potential of a medical device in well defined indications while "all comer studies" reveal the device performance in the real clinical environment. AIMS: This 'all comers' registry assessed the 10-month outcome of the Coroflex(®) Please drug-eluting stent in Europe and Asia by clinically driven major adverse cardiac events. METHODS: The Coroflex(®) Please Registry was an international, prospective, multicenter registry enrolling patients with symptomatic ischemic heart disease. The primary endpoint was clinically driven target lesion revascularization (TLR) at 9 months. Secondary endpoints were technical success, in-hospital outcomes, definite stent thrombosis and major adverse cardiac events (death, myocardial infarction, or TLR) for subgroup analyses. RESULTS: Of the enrolled 1230 patients (63.6 ± 11.2 years, 33.9% diabetics), 339 (27.6%) had an acute coronary syndrome, 148 (12.1%) STEMI and 191 (15.6%) NSTEMI. After 10.5 ± 3.8 months (follow-up rate 92.8%), the target lesion revascularization rate (TLR) was 7.8% overall, 8.3% in STEMI, and 11.3% in NSTEMI patients. Total MACE was 11.1% and significantly higher in ACS with either diabetes mellitus (22.9%, p = 0.017) or age ≥75 years (25.4%, p = 0.026). In European and Asian patients MI rates (5.2% vs 3.1%, p = 0.135) and cardiac death rates (1.6% vs 0.9%, p = 0.414) were similar. The MACE rate was higher in Europe (13.6% vs 4.7%, p < 0.001) driven by a six times higher TLR rate. CONCLUSIONS: TLR and MACE occurred within the range of previously published data. The incidence of MI and cardiac death were not different between Europe and Asia. MACE were higher in Europe driven by target lesion revascularization.