Abstract: Methods and reference compositions for quantifying protein using tagged standards. In an exemplary method, a reference composition and a protein may be electrophoresed in respective lanes of a gel. The reference composition may include quantitation standards of different size and each including a tag present at a different concentration. The quantitation standards and the protein may be transferred from the gel to a solid support to create a blot. Luminescence may be detected from the blot to obtain respective luminescence values separately representing an abundance of the tag of each quantitation standard and an abundance of the protein. A quantity of the protein may be determined using the respective luminescence values.

Abstract: A fluorescence detection system, including apparatus and methods, suitable for qPCR and other fluorescence-based analyses. The system may comprise various components, including a stage, an illumination module, a detection module, and an optical relay structure. The stage may be configured to support a sample holder. The illumination module may include one or more discrete light sources configured to produce excitation light. The detection module may be configured to detect fluorescence emission light produced, in response to the excitation light, by a fluorescent sample positioned in the sample holder. The optical relay structure may include a beamsplitter assembly configured to direct the excitation light from the illumination module along an illumination path to the sample holder and to direct the fluorescence emission light from the sample holder along a response path to the imaging module. The system may enhance the quality of excitation light hitting samples in the sample holder.

Abstract: Methods and reference compositions for quantifying protein using tagged standards. In an exemplary method, a reference composition and a protein may be electrophoresed in respective lanes of a gel. The reference composition may include quantitation standards of different size and each including a tag present at a different concentration. The quantitation standards and the protein may be transferred from the gel to a solid support to create a blot. Luminescence may be detected from the blot to obtain respective luminescence values separately representing an abundance of the tag of each quantitation standard and an abundance of the protein. A quantity of the protein may be determined using the respective luminescence values.

Abstract: An electrophoresis apparatus with minimal autofluorescence to enable gel processing in situ, and methods of making and using the electrophoresis apparatus. An exemplary electrophoresis apparatus may comprise a cassette defining a cavity between a first pane and a second pane of a double-paned viewing window, and also may comprise a slab gel located in the cavity. The viewing window may be transparent to ultraviolet light that drives a derivatization reaction in the slab gel, and, absent the slab gel, may define a window autofluorescence inducible by irradiation with the ultraviolet light. The window autofluorescence, per unit area, may be less than five-fold a gel autofluorescence of the slab gel, per the same unit area and under the same irradiation with the ultraviolet light.

Abstract: An apparatus for dispensing a pressurized stream of gas having particles suspended therein, is described. A double acting pinch valve suitable for use in the apparatus is also described. The apparatus finds particular utility in the dental industry.