We describe a generic approach for realizing networks of pulsating neurons based on charge pumping of interface states situated in the channel of MOS transistors. Two basic building blocks will be described: the pulse activated charge pumping (PSCP) synapse, and the charge sensitive oscillator (CSO). The PSCP synapse which operates as either a short or a long term memory device which produces a charge packet proportional to the number of pulses applied to its input, will be described in detail together with experimental results demonstrating its capability. The CSO circuit which is a charge controlled oscillator will be described together with simulations of its output frequency dependence on its input voltage, and the relation between the temporal dependence of output waveform on its input charge.
The invention relates to a process for prepg. a chitosan-contg. aq. emulsion of an oil comprising the steps of (a) forming an oil-in-water emulsion by homogenizing the oil into an aq. soln. contg. an anionic emulsifier; and (b) adding to the emulsion obtained in (a) an aq. chitosan soln. while continuously homogenizing the mixt. to give a stable emulsion. In further aspect the invention relates to a process for the microcapsulation of fine oil droplets. The invention also relates to sustained-release biodegradable prepns. comprising as active ingredient vitamin E or a UV radiation photoprotectant or a lice repelling agent comprising at least one natural oil or natural oil component thereof and further comprising an anionic emulsifier and chitosan. A lice-repelling emulsion contained rosemary oil 15, chitosan 0.5, citric acid 5, lecithin 0.35, and water 79.15%. The final pH of the emulsion was 3.5 and the emulsion was stable for ≥8 mo at room temp. When the emulsion was applied to human hair fibers, the chitosan microcapsules contg. rosemary oil adhered well to the fiber. [on SciFinder(R)]
A review with 23 refs. The scanning electrochem. microscope (SECM) is one of the scanning probe techniques that were developed following the introduction of the scanning tunneling microscope. The approaches that were used to modify surfaces with lateral resoln. using the SECM are presented and discussed. These approaches made it possible to drive a variety of microelectrochem. reactions on surfaces, as well as to study the mechanism of these processes due to the unique advantages that the SECM offers. [on SciFinder(R)]
A review with 33 refs. Methods of encapsulation, surface activity of proteins, and possible film-forming proteins in drug delivery are discussed. [on SciFinder(R)]
S.Magdassi and Y Vinetsky. 1996. “Microencapsulation of O/W Emulsions by Proteins.” In Microencapsulation Methods and Industrial Applications, edited by Simon Benita, Pp. 21-33. New York: Dekker.
Quantum and mixed quantum/classical calculations of the photolysis of a HCl adsorbate on a MgO surface are reported. In the quantum calculation of the hydrogen dynamics (with rigid surface and chlorine atoms) a strong oscillatory structure is found in the angular distribution of the photofragmented hydrogen as well as in the absorption spectrum. These resonances are caused by temporary trapping of the hydrogen atom between the chlorine atom and the surface and reflect the initial perpendicular adsorption geometry. Corrugation of the surface potential leads to a significant modification of these interference patterns, which exist even for a flat surface. Within a mixed quantum/classical time-dependent self-consistent field (Q/C TDSCF) propagation the influence of surface degrees of freedom on the interference patterns is investigated. The thermal motion of the surface and inelastic collisions of the hydrogen atom with the surface and the chlorine atom washes out most of the oscillatory structure. In the fully angular and energy resolved spectra nevertheless clearly distinguishable peaks are seen. They can be used in practice to extract information about adsorption geometry and surface potential parameters. (C) 1996 American Institute of physics.
Moller-Plesset perturbation theory is employed to improve the accuracy of,static mean field computations in molecular vibration problems, This method is a simple and efficient way to get nearly exact frequencies for few-mode model potentials. For more realistic potentials representing the dynamics of water and formaldehyde, the Moller-Plesset treatment works equally as well, However, we find in general that MP2 level corrections give very accurate energies and additional corrections by higher level terms in the MP series are not substantial. Moreover, we find that for reference states on high energy manifolds degeneracies can result when higher level terms are included in the series, We discuss several ways to remove these degeneracies. (C) 1996 American Institute of Physics.
We present an overview of the modern study of complex fluids which, because of the overwhelming breadth and richness of this field, unavoidably neglects many interesting systems and research developments. In proposing a definition of the field. we discuss first the special role played by phenomenological theory and the limitations of molecular-level description. The remainder of the article is organized into sections which treat model colloids, micellized surfactant solutions, interfacial films and microemulsions, bilayers and membranes, and new materials. In each instance we try to provide a physical basis for the special nature of interactions and long-range ordering transitions in these novel colloidal and thin layer systems. At the heart of understanding these highly varied phenomena lie the curvature dependence of surface energies and the coupling between self-assembly on small length scales and phase changes at large ones..
The dynamics of Cl(P-2) atoms in a solid Ar matrix is studied, with emphasis on electronic energy relaxation of excited states, and on p-orbital reorientation effects. The method used follows Tully's approach for nonadiabatic molecular dynamics simulations, which treats the electronic degrees of freedom quantum-mechanically, and the atomic motions classically, allowing for `'hopping'' of the atoms between different potential energy surfaces. We introduce an extended version of this method, to handle `'Berry Phase'' effects due to the doubly degenerate Kramers pairs of states present in this system. The role of both electrostatic and of spin-orbit interactions between different electronic states is incorporated in the treatment. The simulations yield a time scale of 13 ps for the energy relaxation of the highest excited electronic state of Cl(P-2). A time scale of similar magnitude is found for the depolarization of this state. However, the time scale for orbital reorientation at thermal conditions is only 0.7 ps. This is attributed to the fact that at thermal conditions, only the two lowest electronic states are populated. The physical mechanisms of these basic radiationless decay processes are discussed on the basis of the simulations. (C) 1996 American Institute of Physics.
A method of scanning electrochem. microscope (SECM) was used to analyze the kinetics of the charge transfer at the liq./liq. interface. The method overcomes a limitation requiring a sepn. of ion transfer process from the charge transfer process. Few exptl. results involving iridium and iron complexes are discussed. [on SciFinder(R)]
A patient with Hodgkin's disease (HD) underwent autologous bone marrow transplantation (ABMT). Six months later while receiving interleukin (IL)-2 and alpha-interferon immunotherapy, he developed a painful lesion in his oral cavity with a fistula in the buccal area. Excision biopsy disclosed necrotizing granulomatous inflammation with acid-fast bacillus. The patient received a 9-month course of isoniazide, rifampin and pyrazinamide, and recovered. The possible pathophysiological mechanism is discussed.
