Electroweak Measurements of Neutron Densities in CREX and PREX at JLab, USA

Measurement of the parity-violating electron scattering asymmetry is an established technique at Jefferson Lab and provides a new opportunity to measure the weak charge distribution and hence pin down the neutron radius in nuclei in a relatively clean and model-independent way. This is because the Z boson of the weak interaction couples primarily to neutrons. We will describe the PREX and CREX experiments on ${}^{208}$Pb and ${}^{48}$Ca respectively; these are both doubly-magic nuclei whose first excited state can be discriminated by the high resolution spectrometers at JLab. The heavier lead nucleus, with a neutron excess, provides an interpretation of the neutron skin thickness in terms of properties of bulk neutron matter. For the lighter ${}^{48}$Ca nucleus, which is also rich in neutrons, microscopic nuclear theory calculations are feasible and are sensitive to poorly constrained 3-neutron forces.Comment: A contribution to the upcoming EPJA Special Volume on Nuclear Symmetry Energ

Spatial control of irreversible protein aggregation

Liquid cellular compartments spatially segregate from the cytoplasm and can regulate aberrant protein aggregation, a process linked to several medical conditions, including Alzheimer's and Parkinson's diseases. Yet the mechanisms by which these droplet-like compartments affect protein aggregation remain unknown. Here, we combine kinetic theory of protein aggregation and liquid-liquid phase separation to study the spatial control of irreversible protein aggregation in the presence of liquid compartments. We find that, even for weak interactions between the compartment constituents and the aggregating monomers, aggregates are strongly enriched inside the liquid compartment relative to the surrounding cytoplasm. We show that this enrichment is caused by a positive feedback mechanism of aggregate nucleation and growth which is mediated by a flux maintaining the phase equilibrium between the compartment and the cytoplasm. Our model predicts that the compartment volume that maximizes aggregate enrichment in the compartment is determined by the reaction orders of aggregate nucleation. The underlying mechanism of aggregate enrichment could be used to confine cytotoxic protein aggregates inside droplet-like compartments suggesting potential new avenues against aberrant protein aggregation. Our findings could also represent a common mechanism for the spatial control of irreversible chemical reactions in general

The Holding-Dictum Spectrum

Presumably, the terms holding and dictum have some objective meaning. One would not say, “I do not agree with this statement, so it is dictum.” One might say, “This statement is dictum, so it is not binding.” So what, then, is dictum? More specifically, to what extent does the breadth of a generalization affect its status as holding or dictum

Patent Transfer and the Bundle of Rights

When patents subject to a license agreement are transferred, to what extent do the benefits and burdens of the license agreement run with the patent? Courts have stated that those aspects of the agreement relating to “actual use” of the patent or invention are encumbrances running with the transferred patent. But this doctrinal test is not consistently applied and is not up to the task of clearly and consistently delineating the extent to which patent license agreements run with transferred patents. Conceptualizing the patent as a bundle of Hohfeldian Rights to exclude, this article proposes a more coherent framework for analyzing the extent to which actions by a prior patent owner run with a transferred patent to affect the rights of subsequent owners. The patent owner, through a license agreement or other actions such as selling a patented article, may exchange sticks in the bundle for other forms of value, thus diminishing the size of the in rem bundle of rights. When a patent is transferred, what is transferred is whatever remains in the in rem patent bundle, while the in personam contract remains between the two signatories. Conceptualizing patent transfers in this way could add some degree of precision and clarity to the analysis of the effect of prior license agreements on transferred patents, and hopefully facilitate more coherent development of the law