לוח שנה משולב

The use of proteomics in the clinical arena has been traditionally hampered by low sample throughput and by difficulties in quantifying proteins in complex proteomes in an absolute manner. The use of ultrasonic energy to speed complex proteomics workflows for protein quantification along with thea advent of High Resolution Mass Spectrometry have made possible to treat and to analyze tens of samples a day, thus making mass spectrometry-based clinical proteomics a modern practical tool to be explored.

The recent rapid, global growth of photovoltaics has moved scientific research frontiers for solar energy conversion towards new opportunities including i) ultrahigh efficiency photovoltaics (η > 30%) and ii) direct synthesis of energy-dense chemical fuels from sunlight, including hydrogen and products from reduction of carbon dioxide. I will illustrate several examples of how design of materials for light harvesting, charge transport and catalytic selectivity can enable advances in electricity and fuel synthesis. Photonic design has opened new directions for high efficiency photovoltaics and luminescent solar concentrators. Semiconductors coupled to water oxidation and reduction catalysts have enabled approaches to photoelectrochemical solar-to-hydrogen generation with >19% efficiency using artificial photosynthetic structures. Solar-driven reduction of carbon dioxide presents both an enormous opportunity and challenge because of the need for selectivity in generating useful multi-carbon products by multiple electron and multi-proton transfer steps. Present work and future directions in selective photocatalytic and photo-electrocatalytic materials for artificial photosynthesis aimed at catalytic reduction of carbon dioxide will be discussed.

Nuclear magnetic resonance (NMR) spectroscopy is a powerful analytical tool for the characterization of protein structure and intermolecular interactions. However, NMR is not readily applicable to determine fast structural changes and weak interactions between molecules because of low signal sensitivity and time requirements to record multi-dimensional NMR spectra. To overcome these limits, the hyperpolarization technique of dissolution dynamic nuclear polarization (D-DNP) is combined with NMR. Not all molecules can be directly hyperpolarized. Instead, polarization transfer from hyperpolarized small molecules to a target of interest can be utilized as a means of obtaining polarization, as well as for detecting intermolecular interactions between these molecules Here, hyperpolarized water-assisted NMR spectroscopy was developed to measure intermolecular interactions with water. Firstly, the use of DNP hyperpolarization was demonstrated for the accurate determination of intermolecular cross-relaxation rates between hyperpolarized water and fluorinated target molecules.[1]
Because hyperpolarized water acts as a source spin with a large deviation of the population from the equilibrium, the 19F signal on the target molecules is enhanced through NOE, allowing obtain an entire NOE buildup curve in a single, rapid measurement. When the hyperpolarized water-assisted NMR experiment is applied to a protein, water hyperpolarization can be transferred to amide protons on the protein through proton exchange. Further, this polarization spreads within the protein through intramolecular NOE to nearby protons including aliphatic groups.[2] By utilizing this polarization transfer, this method extends to measure enhanced 2D NMR spectra of the protein under folded and refolding conditions.[3] With the ability to rapidly measure protein signals that were enhanced through transferred polarization from hyperpolarized water, NMR spectra can be acquired within the timescale of the protein folding. Compared to the folded protein experiment, signals attributed to exchange-relayed NOEs are not observable in the refolding experiment (Figure 1b). These differences are explained by the absence of long-range contacts with nearby exchangeable protons such as OH protons