A method of dialysis is provided that includes sensing the concentration of potassium in a patient's blood serum, in used dialysate resulting from treating the patient, or in both. The method involves generating a sensed value of the concentration of potassium, comparing the sensed value with one or more values stored in a memory, and generating a control signal based on the comparison. Supplemental potassium solution is infused into the treatment dialysate, based on the control signal. The comparison can be made to patient-historical data, population data, or both.

The method includes guiding a light beam to a first optical path, the light beam being attenuated to an attenuated light beam and detecting a first value indicative of a first intensity of the attenuated light beam. The method further includes generating a last light pulse, dissociating at least part of the gas compound molecules (optionally excited) or dissociated parts thereof (optionally excited) on the first optical path to first part atoms, molecules, ions, or radicals, and to another part using the last light pulse, the light beam being further attenuated by absorption to the first part atoms, molecules, ions, or radicals on the first optical path. The method further includes detecting a second value indicative of a second intensity of the attenuated light beam and determining, using the first and second values, the gas compound content of the gas mixture. A gas compound measuring device measures uses the method.

Systems and methods of in vivo hydroxyl radical protein foot-printing are presented. These teachings may be used to, for example, study three-dimensional protein structure or bio-kinetics. Radical Dosimetry including an optional intrinsic standard is used on isolated intact cells. Real-time feedback based on an internal standard provides comparability between different experiments and in vivo analysis results in data that is representative of actual biological conditions.

Flash Photo-Oxidation Device and Higher Order Structural Analysis is employed for higher order structural analysis of biomolecules. Biomolecular higher order structure (HOS) results from the confounded superimposition of a biomolecule's secondary, tertiary, and quaternary structure and defines the manner in which a biomolecule presents itself and interacts with other biomolecules in living systems. A rapidly growing class of therapeutic drugs, known as biotherapeutics, comprises a variety of proteins, whose therapeutic properties are inherently linked and dependent upon their HOS. As such, HOS analysis of biotherapeutics is an important analytical requirement in the biopharmaceutical industry. The present invention provides new means and methods for the determination of biopharmaceutical HOS and associated conformation using improved devices and methodologies for flash photo-oxidation of proteins to determine their higher order biomolecular structure, and such is responsive to the increased demand for new and improved HOS analytical means in the biopharmaceutical industry.

The present invention provides a photolytic converter for converting reactant molecules in a fluid sample into product molecules by photolytic dissociation with electromagnetic radiation. The converter has a reaction chamber in communication with one or more electromagnetic radiation sources, an inflow conduit for conveying the fluid sample into the reaction chamber, and an outflow conduit for conveying the fluid sample out of the reaction chamber into a receptacle, wherein at least one of the first and outflow conduits extends into the reaction chamber. The receptacle can comprise detection means for generating a signal indicative of a concentration of product molecules in the processed fluid sample.

A dialysis system is provided that includes a dialysis machine and a potassium sensing device that is configured to measure the concentration of potassium in the patient's blood, in spent dialysate resulting from treating the patient, or in both. The potassium sensing device can be configured to generate a sensed value of the concentration of potassium. A control and computing unit, including a processor and a memory, is configured to receive the sensed value, compare the value with one or more values stored in the memory, and generate a control signal based on the comparison. A potassium infusion circuit uses the control signal to infuse supplemental potassium solution into the treatment dialysate, a replacement fluid, or both. The memory can include stored patient-historical and population data.

A method for spectroscopically detecting a chemical in a gas sample includes illuminating the gas sample with ultraviolet light and photolyzing a first chemical in the gas sample to generate a photolyzed gas sample and spectroscopically detecting a second chemical in the photolyzed gas sample. The second chemical has an optical absorption range within a respective optical absorption range of the first chemical.

The present invention provides a photolytic converter for converting reactant molecules in a fluid sample into product molecules by photolytic dissociation with electromagnetic radiation. The converter has a reaction chamber in communication with one or more electromagnetic radiation sources, an inflow conduit for conveying the fluid sample into the reaction chamber, and an outflow conduit for conveying the fluid sample out of the reaction chamber into a receptacle, wherein at least one of the first and outflow conduits extends into the reaction chamber. The receptacle can comprise detection means for generating a signal indicative of a concentration of product molecules in the processed fluid sample.

A measurement method for visualizing the flow of a fluid that includes: a preparation process where a photochromic compound, whose amount of absorption of light changes upon irradiation with transformation-inducing light, is dissolved in the fluid; a transformation-inducing irradiation process where the fluid is irradiated with transformation-inducing light that causes photochromism; and a post-transformation imaging process where an image of the fluid is taken after irradiation by the transformation-inducing light. During the post-transformation imaging process, a first image is generated by taking an image of the fluid by using first light in the first wavelength range in which the amount of absorption of light changes upon irradiation with transformation-inducing light.

Systems and methods of in vivo and in vitro radical protein foot-printing using an opto-fluidic array are presented. These teachings may be used to, for example, study three-dimensional protein structure or bio-kinetics. Radical dosimetry including an optional intrinsic standard is used. Real-time feedback based on an internal standard provides comparability between different experiments and in vivo and in vitro analysis results in data that is representative of actual biological conditions.