Abstract: A method and apparatus for performing cell cytometry mitigate or eliminate the effects of refraction that result from interfaces between materials having different refractive indices. Solid materials, such as the walls of a flow path, which materials are disposed between a nominal focal point and an objective lens, are formed of a material having a refractive index between 1.30 and 1.40 inclusive. The refractive index of a liquid material, such as an immersion fluid or a fluid carrying, suspending, or bathing an analyte, may be adjusted to have a refractive index closer to that of surrounding solid materials and, in particular, within 0.02 of the refractive index of the surrounding solid materials.

Abstract: A method, apparatus, and system for a sorting flow cytometer include an objective lens having an optical axis coaxially aligned with the flow path at the focal point. A controllable energy source selectively alters an analyte according to a determination of whether the analyte is in a desired sub-population. In various embodiments, one or both of the emission from the controllable energy source and/or the emission from an illumination energy source passes through the objective lens. In some embodiments in which the emission from the controllable energy source passes through the objective lens, the objective lens may focus the emission from the controllable energy source at a different point than the focal point of a signal detected from the analyte and, in particular, at a point closer to the objective lens.

Abstract: A method, apparatus, and system for a sorting flow cytometer include an objective lens having an optical axis coaxially aligned with the flow path at the focal point. A controllable energy source selectively alters an analyte according to a determination of whether the analyte is in a desired sub-population. In various embodiments, one or both of the emission from the controllable energy source and/or the emission from an illumination energy source passes through the objective lens. In some embodiments in which the emission from the controllable energy source passes through the objective lens, the objective lens may focus the emission from the controllable energy source at a different point than the focal point of a signal detected from the analyte and, in particular, at a point closer to the objective lens.

Abstract: An improved process for recovery of virus from allantoic fluid of virus-infected chick embryos. Virus associated with granular and fibrous debris in the allantoic fluid can be disassociated from the debris and recovered, thereby increasing viral yield. Dissociation can be achieved by subjecting the virus-debris complex to conditions of increased salt concentrations, e.g., 0.5 M or greater.