Provided is a coreflood apparatus that comprises a housing, an inlet, an outlet, and two chambers positioned within the housing that are configured to retain porous media. The apparatus includes a partition coupled to an inner surface of the housing between the two chambers and a sensor mounting location. Provided is a method of introducing a fluid into the coreflood apparatus and allowing fluid to pass through chambers in the apparatus having a sensor mounting location there between. Further provided is a coreflood system comprising a coreflood apparatus, a calcium ion sensor, and a data processing device. Provided is a method of introducing fluid into the coreflood system and allowing fluid to pass through chambers in the system having a calcium ion sensor there between. The method further comprises detecting calcium ions in the fluid and determining calcium ion concentration data.

In a method of preparing a liquid solution by mixing ingredients according to a predetermined recipe, wherein at least one pair of species of the liquid solution is derived from a weak electrolyte and corresponds to an acid-base pair, the conductivity of the liquid solution is predicted by: (i) for each pair of species derived from a weak electrolyte, solving a respective equilibrium equation to calculate the actual molar concentration of each such species at equilibrium in the liquid solution, (ii) calculating for each ionic species of said plurality of species the molar conductivity by the formula:
Λ=Λ.sub.0−K×Sqrt(c) wherein Λ is the molar conductivity, Λ.sub.0 is the molar conductivity at infinite dilution, c is the concentration, and K is the Kohlrausch coefficient, and wherein K and Λ.sub.0 are predetermined values for K and Λ.sub.0 for each ionic species, (iii) calculating the conductivity κ for each ionic species by the formula:
κ=c×Λ and (iv) adding up the conductivities determined in step (iii) for the different ionic species to obtain a predicted conductivity of the liquid solution. A computer program product comprises instructions for causing a computer to perform the method steps.

Devices and methods that can detect and control an individual polymer in a mixture is acted upon by another compound, for example, an enzyme, in a nanopore are provided. The devices and methods also determine (˜>50 Hz) the nucleotide base sequence of a polynucleotide under feedback control or using signals generated by the interactions between the polynucleotide and the nanopore. The invention is of particular use in the fields of molecular biology, structural biology, cell biology, molecular switches, molecular circuits, and molecular computational devices, and the manufacture thereof.

The presently claimed invention provides an electrochemical analytical apparatus for electrochemical bath analysis. The apparatus comprise a static electrode and a rotatable unit. As steady liquid flow can be generated on the electrolytic surface of the static electrode by the rotatable unit through rotation, the static disk electrode does not involve any movement during the bath analysis such that the design of the electrical contact in the electrode can be substantially simplified.

The present invention provides an arsenite oxidase enzyme modified to prevent translocation by modification of a translocation signal sequence. A microorganism modified to express the heterologous arsenite oxidase enzyme is also provided by the invention, together with a device for detecting the presence of arsenite in a sample.

Methods and devices for measuring the status of oxidative stress on the surface or in a biological matrix involve use of at least one compound selected from NADH, NADPH, Cyt C (Fe.sup.2+) or H.sub.2O.sub.2.

To enable efficient substance measurement, this invention is characterized in that the invention comprises a first hollow fiber (131) for allowing a first processing liquid to flow from a first introduction port (121a) to a first exit port (121b) and allowing the membrane permeation of gas in the processing liquid, a second hollow fiber (132) for allowing a second processing liquid to flow from a second introduction port (122a) to a second exit port (122b) and allowing the membrane permeation of gas in the processing liquid, a container (110) for accommodating the first hollow fiber (131) and second hollow fiber (132) therein, and a vacuum pump (201) connected to the space (S) inside the container (110), and inside the container (110), the hollow fibers (130) consisting of the first hollow fiber (131) and second hollow fiber (132) are in contact with each other across a prescribed length.

Apparatus (2) for sensing at least one parameter in water, which apparatus (2) comprises: (i) at least one electrode based sensor (4, 6) for sensing at least one parameter in water; and which apparatus (2) is such that: (ii) the electrode based sensor (4, 6) has a self-cleaning electrode; (iii) the electrode based sensor (4, 6) has a reference electrode; (iv) the self-cleaning electrode is stable in water; (v) the apparatus (2) is configured to operate by liberating chlorine from the water using a first waveform applied to the self-cleaning electrode; (VI) the apparatus (2) is configured to operate by liberating chlorine and oxygen from the water using a second waveform applied to the self-cleaning electrode; and (VII) the apparatus (2) is configured to preserve the condition of the reference electrode by periodically regenerating the reference electrode.

A method of determining a concentration of phenol and/or a phenol derivative in a first solution. The method includes (a) subjecting a graphite pencil electrode system comprising a graphite pencil working electrode, a counter electrode, and a reference electrode to cyclic voltammetry in a second solution such that a surface of the graphite pencil working electrode is charged by the cyclic voltammetry to form a charged surface, (b) contacting the charged surface of the graphite pencil working electrode with the first solution for sufficient time to electropolymerize the phenol and/or the phenol derivative on the charged surface in open circuit fashion, and (c) determining the concentration of the phenol and/or the phenol derivative in the first solution, wherein the amount of the electropolymerized phenol and/or the electropolymerized phenol derivative formed on the charged surface correlates with the concentration of the phenol and/or the phenol derivative in the first solution.

The invention aims to suppress an effect of noise and heat generated from a memory on a measurement result in an ion concentration measuring device that uses an ion detection element for outputting a potential corresponding to the concentration of ions. The ion concentration measuring device according to the invention includes a cartridge having an ion detection element and a memory and supplies power to the memory in a time period excluding a time period for which the potential generated by the ion detection element is acquired.