A discrete time relativistic Toda lattice

Four integrable symplectic maps approximating two Hamiltonian flows from the relativistic Toda hierarchy are introduced. They are demostrated to belong to the same hierarchy and to examplify the general scheme for symplectic maps on groups equiped with quadratic Poisson brackets. The initial value problem for the difference equations is solved in terms of a factorization problem in a group. Interpolating Hamiltonian flows are found for all the maps.Comment: 32 pages, LaTe

Intrinsic high aerobic capacity protects against lipid induced hepatic insulin resistance [abstract]

Hepatic steatosis is commonly linked to hepatic insulin resistance. However, recent studies have found that increased hepatic triacylglycerol (TAG) accumulation is not always associated with impaired hepatic insulin signaling, leading to a hypothesis that partitioning of lipids into TAG in the liver matched with high rates of fatty acid oxidation (FAO) under high lipid exposure conditions may protect against hepatic insulin resistance. We examined this hypothesis in the livers of high and low capacity running (HCR/LCR) rats which were created by artificial selection based on differences in intrinsic aerobic capacity

Bypassing H\"older super-critcality barriers in viscous, incompressible fluids

This is the second in a series of papers where we analyze the incompressible Navier-Stokes equations in H\"older spaces. We obtain, to our knowledge, the very first genuinely super-critical regularity criterion for this system of equations in any dimension $d\geq3$ and in the absence of physical boundaries. For \emph{any} $\beta\in(0,1)$, we show that $L_t^1C_x^{0,\beta}$ solutions emanating from smooth initial data do not develop any singularities. The novelty stems from obtaining new bounds on the fundamental solution associated with a one-dimensional drift-diffusion equation in the presence of destabilizing singular lower order terms. Such a bound relies heavily on the symmetry and pointwise structure of the problem, where the drift term is shown to ``enhance'' the parabolic nature of the equation, allowing us to break the criticality barrier. Coupled with a subtle regularity estimate for the pressure courtesy of Silvestre, we are able to treat the (incompressible) Navier-Stokes equation as a perturbation of the classical drift-diffusion problem. This is achieved by propagating moduli of continuity as was done in our previous work, based on the elegant ideas introduced by Kiselev, Nazarov, Volberg and Shterenberg

Mineralocorticoid receptor antagonism attenuates vascular apoptosis and injury via rescuing protein kinase B activation

This article may also be found at the publisher's website at http://hyper.ahajournals.org/cgi/content/abstract/53/2/158?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=habibi&searchid=1&FIRSTINDEX=0&resourcetype=HWCITEmerging evidence indicates that mineralocorticoid receptor (MR) blockade reduces the risk of cardiovascular events beyond those predicted by its blood pressure-lowering actions; however, the underlying mechanisms remain unclear. To investigate whether protection elicited by MR blockade is through attenuation of vascular apoptosis and injury, independently of blood pressure lowering, we administered a low dose of the MR antagonist spironolactone or vehicle for 21 days to hypertensive transgenic Ren2 rats with elevated plasma aldosterone levels. Although Ren2 rats developed higher systolic blood pressures compared with Sprague-Dawley littermates, low-dose spironolactone treatment did not reduce systolic blood pressure compared with untreated Ren2 rats. Ren2 rats exhibited vascular injury as evidenced by increased apoptosis, hemidesmosome-like structure loss, mitochondrial abnormalities, and lipid accumulation compared with Sprague-Dawley rats, and these abnormalities were attenuated by MR antagonism. Protein kinase B activation is critical to vascular homeostasis via regulation of cell survival and expression of apoptotic genes. Protein kinase B serine473 phosphorylation was impaired in Ren2 aortas and restored with MR antagonism. In vivo MR antagonist treatment promoted antiapoptotic effects by increasing phosphorylation of BAD serine136 and expression of Bcl-2 and Bcl-xL, decreasing cytochrome c release and BAD expression, and suppressing caspase-3 activation. Furthermore, MR antagonism substantially reduced the elevated NADPH oxidase activity and lipid peroxidation, expression of angiotensin II, angiotensin type 1 receptor, and MR in Ren2 vasculature. These results demonstrate that MR antagonism protects the vasculature from aldosterone-induced vascular apoptosis and structural injury via rescuing protein kinase B activation, independent of blood pressure effects

β‐Ionone: Its Occurrence and Biological Function and Metabolic Engineering

β‐Ionone is a natural plant volatile compound, and it is the 9,10 and 9’,10’ cleavage prod-uct of β‐carotene by the carotenoid cleavage dioxygenase. β‐Ionone is widely distributed in flowers, fruits, and vegetables. β‐Ionone and other apocarotenoids comprise flavors, aromas, pigments, growth regulators, and defense compounds; serve as ecological cues; have roles as insect attractants or repellants, and have antibacterial and fungicidal properties. In recent years, β‐ionone has also received increased attention from the biomedical community for its potential as an anticancer treatment and for other human health benefits. However, β‐ionone is typically produced at relatively low levels in plants. Thus, expressing plant biosynthetic pathway genes in microbial hosts and engineering the metabolic pathway/host to increase metabolite production is an appealing alternative. In the present review, we discuss β‐ionone occurrence, the biological activities of β‐ionone, empha-sizing insect attractant/repellant activities, and the current strategies and achievements used to re-construct enzyme pathways in microorganisms in an effort to to attain higher amounts of the de-sired β‐ionone