We have developed a simple microfluidic device for generating stable concentration gradients in 2D and 3D environments. The device, termed the Ladder Chamber, uses a two-compartment diffusion system to generate steady state gradients across flow-free channels that connect the source and sink channels. To demonstrate the utility of the Ladder Chamber for cell migration, neutrophil chemotaxis was...

Dependency relations between objects in a railway yard are tabulated in control tables. An interlocking, which guarantees validity of these dependencies, can be implemented in ladder logic. We transform a ladder logic diagram into a Boolean formula, so that validity of the dependencies in the control tables can be veri ed using a theorem prover. Time copies and invariants are added to the formu...

We investigate the thermal and magnetic properties of the integrable su(4) ladder model by means of the quantum transfer matrix method. The magnetic susceptibility, specific heat, magnetic entropy, and high field magnetization are evaluated from the free energy derived via the recently proposed method of high temperature expansion for exactly solved models. We show that the integrable model can...

The phase diagram in temperature and magnetic field of the metal-organic, two-leg, spin-ladder compound (C5H12N)2CuBr4 is studied by measurements of the specific heat and the magnetocaloric effect. We demonstrate the presence of an extended spin Luttinger-liquid phase between two field-induced quantum critical points and over a broad range of temperature. Based on an ideal spin-ladder Hamiltoni...

This paper presents evidence on a national-level electricity ladder which sees countries transition toward coal and natural gas, and finally nuclear power and modern renewables such as wind power, for their electricity needs as they develop. The extent to which countries climb the electricity ladder is dependent on energy endowments. The results imply that the environmental implications of econ...

We consider a two-leg ladder system with interactions varying from constant rung coupling to systematic diminishing of rung interactions leading to diverging chains. We compare and contrast their ground state and excitation characteristics using density matrix renormalization group methods. We find that the finite spin gap in a constant coupling ladder develops into a gapless excitation with sl...

We report the identification and construction of raising and lowering operators for the complete eigenfunctions of isotropic harmonic oscillators confined by dihedral angles, in circular cylindrical and spherical coordinates; as well as for the hydrogen atom in the same situation of confinement, in spherical, parabolic and prolate spheroidal coordinates. The actions of such operators on any eig...

It is shown that the integration measure over the matrix Y in the matrix representation of the Schild action can be fixed from comparison of the Schild matrix model with the random lattice string model for D = 0. It is further checked that the given measure is consistent with the case D = 1 as well. ∗e-mail: [email protected]

Deviation equation of Synge and Schild has been investigated over dif-ferentiable manifolds with contravariant and covariant affine connections (whose components differ not only by sign) and metric [(Ln, g)-spaces]. It is shown that the condition £ ξ u = 0 for obtaining this equation is only a sufficient (but not necessary) condition. By means of a non-isotropic (non-null) vector field u [g(u, ...