Notes on nonabelian (0,2) theories and dualities

In this paper we explore basic aspects of nonabelian (0,2) GLSM's in two dimensions for unitary gauge groups, an arena that until recently has largely been unexplored. We begin by discussing general aspects of (0,2) theories, including checks of dynamical supersymmetry breaking, spectators and weak coupling limits, and also build some toy models of (0,2) theories for bundles on Grassmannians, which gives us an opportunity to relate physical anomalies and trace conditions to mathematical properties. We apply these ideas to study (0,2) theories on Pfaffians, applying recent perturbative constructions of Pfaffians of Jockers et al. We discuss how existing dualities in (2,2) nonabelian gauge theories have a simple mathematical understanding, and make predictions for additional dualities in (2,2) and (0,2) gauge theories. Finally, we outline how duality works in open strings in unitary gauge theories, and also describe why, in general terms, we expect analogous dualities in (0,2) theories to be comparatively rare.Comment: 93 pages, LaTeX; v2: typos fixe

L-Tetrahydropalamatine: A Potential New Medication for the Treatment of Cocaine Addiction

Levo-tetrahydropalmatine (l-THP) is an active constituent of herbal preparations containing plant species of the genera Stephania and Corydalis and has been approved and used in China for a number of clinical indications under the drug name Rotundine. The pharmacological profile of l-THP, which includes antagonism of dopamine D1 and D2 receptors and actions at dopamine D3, α adrenergic and serotonin receptors, suggests that it may have utility for treating cocaine addiction. In this review, we provide an overview of the pharmacological properties of l-THP and the evidence supporting its development as an anti-addiction medication. The results of preclinical work demonstrating that l-THP attenuates cocaine’s reinforcing/rewarding effects and reinstatement in rat models of cocaine relapse are summarized, and the outcomes of studies demonstrating efficacy in human addicts are described. Finally, an overview of the safety profile of l-THP is provided and challenges associated with US FDA approval of l-THP are discussed

Entropy and biological systems: experimentally-investigated entropy-driven stacking of plant photosynthetic membranes

According to the Second Law of thermodynamics, an overall increase of entropy contributes to the driving force for any physicochemical process, but entropy has seldom been investigated in biological systems. Here, for the first time, we apply Isothermal Titration Calorimetry (ITC) to investigate the Mg21-induced spontaneous stacking of photosynthetic membranes isolated from spinach leaves. After subtracting a large endothermic interaction of MgCl2 with membranes, unrelated to stacking, we demonstrate that the enthalpy change (heat change at constant pressure) is zero or marginally positive or negative. This first direct experimental evidence strongly suggests that an entropy increase significantly drives membrane stacking in this ordered biological structure. Possible mechanisms for the entropy increase include: (i) the attraction between discrete oppositely-charged areas, releasing counterions; (ii) the release of loosely-bound water molecules from the inter-membrane gap; (iii) the increased orientational freedom of previously-aligned water dipoles; and (iv) the lateral rearrangement of membrane components.This work was supported consecutively by Australian Research Council grants (DP0664719 and DP 1093927)