`Similar' coordinate systems and the Roche geometry. Application

A new equivalence relation, named relation of 'similarity' is defined and applied in the restricted three-body problem. Using this relation, a new class of trajectories (named 'similar' trajectories) are obtained; they have the theoretical role to give us new details in the restricted three-body problem. The 'similar' coordinate systems allow us in addition to obtain a unitary and an elegant demonstration of some analytical relations in the Roche geometry. As an example, some analytical relations published in Astrophysical Journal by Seidov in 2004 are demonstrated.Comment: 9 pages (preprint format), 9 figures, published in Astrophysics and Space Scienc

On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

The selective serotonin reuptake inhibitor fluoxetine improves glucose homeostasis in vivo by promoting insulin secretion and maintaining functional β-cell mass

Aim: We previously showed that therapeutically relevant concentrations of fluoxetine stimulated insulin secretion and increased beta cell proliferation in vitro. This study investigated the effect of fluoxetine on glucose homeostasis in mice and humans in vivo. Methods: ob/ob mice were administered four doses of fluoxetine (10mg/kg body weight) or vehicle intraperitoneally over two weeks before undergoing intraperitoneal glucose tolerance tests. Bromodeoxyuridine (BrdU) (1mg/ml) was provided for seven days before they were killed. Insulin secretion from perifused islets was measured by radioimmunoassay. Islet beta cell proliferation was identified by immunohistochemistry. In a multi‐ethnic primary care cohort with newly diagnosed Type 2 diabetes, we compared patients prescribed fluoxetine with controls for one‐year changes in plasma insulin and HbA1c in univariate and multivariate analyses. Results: Fluoxetine improved glucose handling in ob/ob mice (control vs fluoxetine; time (T) = 0: 6.7 ± 0.8 mM glucose vs 6.5 ± 0.5; p > 0.5; T = 210min: 36.3 ± 8.5 mM vs 16.5 ± 2.4; p < 0.05; n = 5), most likely a consequence of increased beta cell proliferation (BrdU positive beta cells/islet: 0.30 ± 0.17 vs 12.15 ± 2.88; n = 20; p < 0.001) and enhanced insulin secretion in response to 20mM glucose (area under the curve, pg insulin/20min: 304.8 ± 28.7 vs 464.7 ± 34.2; n = 4; p < 0.001). Patients prescribed fluoxetine (n = 14) showed significant improvement in plasma insulin vs controls (n = 615) (β = 13.35 (1.84 to 23.85), p = 0.023) after adjustment for age, gender, ethnicity vascular risk factors and change in depressive symptoms. In patients prescribed fluoxetine, HbA1c improved non‐significantly (0.54% vs 0.05%) vs controls. Conclusions: These data support a role for fluoxetine in improving beta cell function in diabetic animals and in patients with early Type 2 diabetes. Repurposing of fluoxetine, thus, represents a novel therapeutic strategy for the management of Type 2 diabetes