לוח שנה משולב

Almost all energy (and hence most fuels and organic chemicals) derive from fossil fuels (natural gas, oil or coal) that in turn derive from solar energy. However the fuels must first be converted and refined (purified) into easily usable forms. For transportation (ca. 27% of global energy use) the fuel should be in a convenient liquid form. The Second Law of Thermodynamics .indicates that conversion can involve large losses which should be minimised The most usual technology involves reforming the fossil fuel into syngas, CO + H2. The syngas is then converted into largely n-alkanes and n-1-alkenes over heterogeneous catalysts (metallic Fe or Co, 250-350oC) in the very exothermic Fischer-Tropsch (FT) reaction. The precise processes that occur on the FT catalyst are still not completely clear, but the Dual Path mechanism seems to answer most questions. Here the reaction paths are determined by the interplay of the metal and support surfaces and the surface organics. In the (classical) Dissociative Mechanism the surface is regarded as neutral and only neutral organic / species, eg., {C}, {CH}, {CHn}, etc are involved. In the Associative Mechanism, more polar steps involving electrophiles and nucleophiles, eg., {CHOH}; {CHδ+} occur,
The key building block in the normal FT process is CO, but “climate change” considerations indicate that CO2 would be a very useful raw material. Can this work?

We are interested in understanding how memories are encoded and retained in the brain and use different methods to uncover the basic molecular and cellular mechanisms underlying learning. Following accumulation of basic science research and data, we recently try to find new ways to enhance memory. Very little is known about drugs which can enhance the consolidation phase of memories in the cortex, the brain structure considered to store at least partially, long term memories. We tested the hypothesis that pharmacological and genetic manipulation of translation machinery, known to be involved in the molecular consolidation phase, enhances positive or negative forms of cortical dependent memories. We found that dephosphorylation (Ser51) of eIF2α specifically in the cortex is both correlated and necessary for normal memory consolidation. In order to reduce eIF2α phosphorylation and improve memory consolidation, we pharmacologically or genetically inhibited the different eIF2α kinases expressed in the brain. In addition, we tested the involvement of eIF2α pathway in mice models of aging and sporadic Alzheimer disease and found strong link between the two.
Relevant recent publications:
1. Costa-Mattioli M, Gobert D, Stern E, Gamache K, Colina R, Cuello C, Sossin W, Kaufman R, Pelletier J, Rosenblum K, Krnjević K, Lacaille JC, Nader K, Sonenberg N (2007). eIF2 phosphorylation regulates the switch from short to long-term synaptic plasticity and memory. Cell 6;129(1):195-206. http://www.ncbi.nlm.nih.gov/pubmed/17418795
2. ApoE ε4 is associated with eIF2α phosphorylation and impaired learning in young mice (2013). Yifat Segev, Daniel M. Michaelson, Kobi Rosenblum Neurobiology of Aging.
http://www.ncbi.nlm.nih.gov/pubmed/22883908
3. Blocking eIF2a kinase – PKR – Enhances Positive and Negative Forms of Cortex-Dependent Taste Memory (2013). Stern Elad, Chinnakkaruppan Adaikkan, David Orit ,Sonenberg Nahum and Rosenblum Kobi. Journal of Neuroscience (in press).