לוח שנה משולב

Over the past 65 million years, the evolution of mammals led - in several lineages - to a dramatic increase in brain size. During this process, some neocortical areas, including the primary sensory ones, expanded by many orders of magnitude. The primary visual cortex, for instance, measured about a square millimeter in late cretaceous stem eutherians but in homo sapiens comprises more than 2000 mm2. If we could rewind time and restart the evolution of large and large brained mammals, would the network architecture of neocortical circuits take the same shape or would the random tinkering process of biological evolution generate different or even fundamentally distinct designs?
In this talk, I will argue that, based on the consolidated mammalian phylogenies available now, this seemingly speculative question can be rigorously approached using a combination of quantitative brain imaging, computational, and dynamical systems techniques. Our studies on visual cortical circuit layout in a broad range of eutherian species indicate that neuronal plasticity and developmental network self-organization have restricted the evolution of neuronal circuitry underlying orientation columns to a few discrete design alternatives.
Our theoretical analyzes predict that different evolutionary lineages adopt virtually identical circuit designs when using only qualitatively similar mechanisms of developmental plasticity.

The development of molecular semiconductors for optoelectronic devices has tremendous impact on energy production. However, a major challenge to attain widespread implementation of this technology would be to develop materials by cost effective methods and achieve high stability. Although this can pose a great challenge, the concept of bulk heterojunction has provided the record breaking efficiency of as high as 9.2%. However, a clear relationship between the material properties and stability is still lacking. In this talk, the role of torsional defects in molecular semiconductor shall be discussed. Moreover, our recent results of ambipolar molecular semiconductors for organic field-effect transistors (OFET) will be highlighted.

References:
1) Influence of Side-Chain on Structural Order and Photophysical Properties in Thiophene Based Diketopyrrolopyrroles: A Systematic Study, Mallari A. Naik, N. Venkatramaiah, Catherine Kanimozhi, and Satish Patil*, Journal of Physical Chemistry-C, 2012, 116, 26128–26137

2) Diketopyrrolopyrrole-Diketopyrrolopyrrole-Based Conjugated Copolymer for High-Mobility Organic Field-Effect Transistors, Kanimozhi, C.; Yaacobi-Gross, N.; Chou, K. W.; Amassian, A.; Anthopoulos, T. D.; Satish Patil, J. Am. Chem. Soc. 2012, 134, 16532

The longstanding reliance on fossil fuels as the principal energy source for society has boosted the atmospheric CO2 concentration to a level that is unprecedented in modern geological history. Since the use of carbon-containing fuels is entrenched in society, controlling the atmospheric CO2 concentration may ultimately require recycling CO2 into liquid fuels and commodity chemicals using renewable energy inputs. Arguably the greatest challenge for this vision is to develop efficient CO2 reduction catalysts. This talk will describe our recent development of “oxide-derived” metal nanoparticles as electroreduction catalysts. Oxide-derived metal nanoparticles are prepared by electrochemically reducing metal oxide precursors. This procedure results in highly strained metal nanocrystals. I will describe examples of these catalysts that electrochemically reduce CO2 to CO with exceptional energetic efficiency as well as a catalyst that selectively reduces CO to two-carbon oxygenates. The mechanisms of CO2 and CO reduction will be discussed based on electrokinetic measurements. Metal oxide reduction represents a “top-down” approach to metal nanoparticle synthesis that can result in unique surface structures for catalysis.