The F-ATPase of the bacterium Propionigenium modestum is driven by an electrochemical sodium gradient between the cell interior and its environment. Here we present a mechanochemical model for the transduction of transmembrane sodium-motive force into rotary torque. The same mechanism is likely to operate in other F-ATPases, including the proton-driven F-ATPases of Escherichia coli.

Unilamellar vesicles composed of phosphatidylcholine (PC) and either phosphatidic acid (PA) or phosphatidylglycerol (PG) partition to the upper poly(ethylene glycol) (PEG)-rich phase of a charge-sensitive 5%:5% (w/w) PEG 8000/Dextran T-500 phase system containing 10 mM sodium phosphate at pH 7, consistent with the vesicles bearing a net negative charge. When prepared in the presence of a pH gra...

Thermal Contact Conductance (TCC) between an exhaust valve and its seat is one of the important parameters to be estimated in an internal combustion engine. An experimental study presented here to acquire temperature in some interior points to be used as inputs to an inverse analysis. An actual exhaust valve and its seat are utilized in a designed and constructed setup. Conjugate Gradient Metho...

Let v be a hyperbolic equilibrium of a smooth finite-dimensional gradient or gradient-like dynamical system. Assume that the unstable manifold W of v is bounded, with topological boundary Σ = ∂W := (closW )\W . Then Σ need not be homeomorphic to a sphere, or to any compact manifold. However, consider PDEs ut = uxx + f(x, u, ux) of Sturm type, i.e. scalar reaction-advection-diffusion equations i...

A light-induced proton gradient (DeltapH) increase as exhibited by an increase of 9-aminoacridine fluorescence quenching is demonstrated between the external medium and the interior of the halophytic green alga Dunaliella salina. The formation and maintenance of the DeltapH is sensitive to electron transport inhibitors and to uncouplers. It is inhibited by p-chloromercuribenzenesulfonic acid (5...

Glutamate is released from synaptic vesicles following formation of a fusion pore, connecting the vesicle interior with the synaptic cleft. Release is proposed to result from either full fusion of the vesicle with the terminal membrane or by 'kiss-and-run,' where release occurs through the fusion pore. 'Kiss-and-run' seems implausible as passive diffusion of glutamate through the pore is too sl...

Although predispersal seed predation by insects is common, no test exists of its effect on plant recruitment. This study examines seed predation in the population dynamics of a native, temperate shrub, Haplopappus squarrosus H. and A. (Asteraceae), over an elevational gradient in the coastal sage scrub vegetation of San Diego County, California USA. Frequency and abundance of H. squarrosus incr...

A total of 31 years of abundance data from 90 populations of the grey-sided vole (Clethrionomys rufocanus) in northern Hokkaido (Japan) were analysed with respect to population dynamic characteristics. Both non-periodic and multi-annually periodic fluctuations occur among the studied populations. The length of the period varies from 2 to 5 years. The dynamics appear approximately linear on a lo...

We study some continuous dynamical systems associated with constrained optimization problems. For that purpose, we introduce the concept of elliptic barrier operators and develop a unified framework to derive and analyze the associated class of gradient-like dynamical systems, called A-Driven Descent Method (A-DM). Prominent methods belonging to this class include several continuous descent met...

In this paper, we construct a new approach of affine scaling interior algorithm using the affine scaling conjugate gradient and Lanczos methods for bound constrained nonlinear optimization. We get the iterative direction by solving quadratic model via affine scaling conjugate gradient and Lanczos methods. By using the line search backtracking technique, we will find an acceptable trial step len...