1. The extracellular patch clamp method, which first allowed the detection of single channel currents in biological membranes, has been further refined to enable higher current resolution, direct membrane patch potential control, and physical isolation of membrane patches. 2. A description of a convenient method for the fabrication of patch recording pipettes is given together with procedures followed to achieve giga-seals i.e. pipette-membrane seals with resistances of 10(9) - 10(11) omega. 3. The basic patch clamp recording circuit, and designs for improved frequency response are described along with the present limitations in recording the currents from single channels. 4. Procedures for preparation and recording from three representative cell types are given. Some properties of single acetylcholine-activated channels in muscle membrane are described to illustrate the improved current and time resolution achieved with giga-seals. 5. A description is given of the various ways that patches of membrane can be physically isolated from cells. This isolation enables the recording of single channel currents with well-defined solutions on both sides of the membrane. Two types of isolated cell-free patch configurations can be formed: an inside-out patch with its cytoplasmic membrane face exposed to the bath solution, and an outside-out patch with its extracellular membrane face exposed to the bath solution. 6. The application of the method for the recording of ionic currents and internal dialysis of small cells is considered. Single channel resolution can be achieved when recording from whole cells, if the cell diameter is small (less than 20 micrometer). 7. The wide range of cell types amenable to giga-seal formation is discussed.

/pdf/improved-patch-clamp-techniques-for-high-resolution-current-tmno572o60.pdf

Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches.

Multilayer films of organic compounds on solid surfaces have been studied for more than 60 years because they allow fabrication of multicomposite molecular assemblies of tailored architecture. However, both the Langmuir-Blodgett technique and chemisorption from solution can be used only with certain classes of molecules. An alternative approach—fabrication of multilayers by consecutive adsorption of polyanions and polycations—is far more general and has been extended to other materials such as proteins or colloids. Because polymers are typically flexible molecules, the resulting superlattice architectures are somewhat fuzzy structures, but the absence of crystallinity in these films is expected to be beneficial for many potential applications.

https://science.sciencemag.org/content/sci/277/5330/1232.full.pdf

Fuzzy Nanoassemblies: Toward Layered Polymeric Multicomposites

Quantitative analysis of dose-effect relationships: the combined effects of multiple drugs or enzyme inhibitors

https://chemical.eng.usm.my/bassim/PDF/adsorption%20isotherm.pdf

Insights into the modeling of adsorption isotherm systems

The calculation of rate coefficients is a discipline of nonlinear science of importance to much of physics, chemistry, engineering, and biology. Fifty years after Kramers' seminal paper on thermally activated barrier crossing, the authors report, extend, and interpret much of our current understanding relating to theories of noise-activated escape, for which many of the notable contributions are originating from the communities both of physics and of physical chemistry. Theoretical as well as numerical approaches are discussed for single- and many-dimensional metastable systems (including fields) in gases and condensed phases. The role of many-dimensional transition-state theory is contrasted with Kramers' reaction-rate theory for moderate-to-strong friction; the authors emphasize the physical situation and the close connection between unimolecular rate theory and Kramers' work for weakly damped systems. The rate theory accounting for memory friction is presented, together with a unifying theoretical approach which covers the whole regime of weak-to-moderate-to-strong friction on the same basis (turnover theory). The peculiarities of noise-activated escape in a variety of physically different metastable potential configurations is elucidated in terms of the mean-first-passage-time technique. Moreover, the role and the complexity of escape in driven systems exhibiting possibly multiple, metastable stationary nonequilibrium states is identified. At lower temperatures, quantum tunneling effects start to dominate the rate mechanism. The early quantum approaches as well as the latest quantum versions of Kramers' theory are discussed, thereby providing a description of dissipative escape events at all temperatures. In addition, an attempt is made to discuss prominent experimental work as it relates to Kramers' reaction-rate theory and to indicate the most important areas for future research in theory and experiment.

Reaction-rate theory: fifty years after Kramers

solutions investigated, the absorption index diminishing approximately 1% for a rise in temperature of one degree. 6. In liquid ammonia rough measurements of concentration showed the absorption index to be proportional to the total concentration of metal. 7. In methylamine the absorption index, at the wave length of the band maximum is also proportional to the total concentration of metal. At shorter wave lengths, however, deviations were observed, the absorption increasing more rapidly with concentration than Beers’ law would demand. The ratio of the absorption index a t 650pp to that a t 53opp increases not only with increasing concentration of the metal but also with increasing concentration of the reaction product of the metal with methylamine, and probably also with increasing temperature. 8. These observations can be accounted for by the following hypotheses: The color in all cases is due to electrons combined with the solvent. In ammonia the dissociation of the metal into electrons is nearly complete, and the concentration of electrons uncombine4 with solvent is negligible compared with that of the solvated electrons. In other words, the solvation of the electrons is nearly complete. In methylamine, on the other hand, the concentration of un-ionized metal is no longer negligible and is responsible for the increased absorption a t the shorter wave lengths. The solvation of the electrons in methylamine is incomplete and diminishes as the temperature is increased.

/pdf/the-adsorption-of-gases-on-plane-surfaces-of-glass-mica-and-521324ctfv.pdf

The adsorption of gases on plane surfaces of glass, mica and platinum.

The constitution and fundamental properties of solids and liquids

/pdf/the-constitution-and-fundamental-properties-of-solids-and-1v3423xxi3.pdf

The constitution and fundamental properties of solids and liquids. part i. solids.

/pdf/the-constitution-and-fundamental-properties-of-solids-and-1ld97x2lcb.pdf

The constitution and fundamental properties of solids and liquids. ii. liquids.1

When a cylindrical or spherical electrode (collector) immersed in an ionized gas is brought to a suitable potential, it becomes surrounded by a symmetrical space-charge region or "sheath" of positive or of negative ions (or electrons). Assuming that the gas pressure is so low that the proportion of ions which collide with gas molecules in the sheath is negligibly small, the current taken by the collector can be calculated in terms of the radii of the collector or sheath, the distribution of velocities among the ions arriving at the sheath boundary and the total drop of potential in the sheath. The current is independent of the actual distribution of potential in the sheath provided this distribution satisfies certain conditions.

Irving Langmuir

Papers

The adsorption of gases on plane surfaces of glass, mica and platinum.

The constitution and fundamental properties of solids and liquids

The constitution and fundamental properties of solids and liquids. part i. solids.

The constitution and fundamental properties of solids and liquids. ii. liquids.1

The Theory of Collectors in Gaseous Discharges