Integrated Calendar

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

Recent discoveries have shown that habitable environments likely exist in subsurface water oceans within the outer planet moons of Europa and Enceladus. On Titan, the largest moon of Saturn, lakes and seas of liquid hydrocarbon exist in addition to a vast subsurface water ocean. These places represent ideal locations for hydrothermal environments that could sustain life as we know it and, in Titan’s case, perhaps even life as we don’t. The next generation of uncrewed planetary spacecraft will be designed to search for the signs of life in one or more of these worlds. This lecture will begin with a brief review of the discoveries that have motivated a renewed importance for Ocean World exploration, before diving into Titan's lakes and seas to discuss recent findings related to its hydrocarbon-based hydrologic cycle and setting the stage for the newly selected Dragonfly quadcopter set to explore Titan in the mid 2030s.

The biological response to stress is concerned with the maintenance of homeostasis in the presence of real or perceived challenges. This process requires numerous adaptive responses, involving changes in the central nervous and neuroendocrine systems. When a situation is perceived as stressful, the brain activates many neuronal mechanisms and circuits, linking centers involved in sensory, motor, autonomic, neuroendocrine, cognitive, and emotional functions in order to adapt to the demand. However, the details of the pathways by which the brain translates stressful stimuli into the final, integrated biological response are not completely understood. Nevertheless, it is clear that dysregulation of these physiological responses to stress can have severe psychological and physiological consequences, and there is substantial evidence to suggest that inappropriate regulation, disproportional intensity, or chronic and/or irreversible activation of the stress response is linked to the etiology and pathophysiology of anxiety, depression and metabolic-related disorders. The lecture will review our recent knowledge and findings of stress response neurobiology and stress-induced psychiatric disorders.

Collective decision-making regarding direction of travel is observed during natural motion of animal and cellular groups. This phenomenon is exemplified, in the simplest case, by a group that contains two informed subgroups that hold conflicting preferred directions of motion. Under such circumstances, simulations, subsequently supported by experimental data with birds and primates, have demonstrated that the resulting motion is either towards a compromise direction or towards one of the preferred targets (even when the two subgroups are equal in size). However, the nature of this transition is not well understood. We present a theoretical study that combines simulations and a spin model for mobile animal groups. This allows us to identify the nature of this transition at a critical angular difference between the two preferred directions: in both flocking and spin models the transition coincides with the change in the group dynamics from Brownian to persistent collective motion. The groups undergo this transition as the number of uninformed individuals (those in the group that do not exhibit a directional preference) increases, which acts as an inverse of the temperature (noise) of the spin model. When the two informed subgroups are not equal in size, there is a tendency for the group to reach the target preferred by the larger subgroup. We find that the spin model captures effectively the essence of the collective decision-making transition and allows us to reveal a noise-dependent trade-off between the decision-making speed and the ability to achieve majority (democratic) consensus.