Abstract: An improved optical flow cell adapted for use in a flow cytometer for differentiating formed bodies (e.g., blood cells) in liquid suspensions. Preferably manufactured by assembling, aligning, and optically joining at least two elements made from transparent material, the improved flow cell has a seamless internal flow channel of preferably non-circular cross-section in a cylindrical first element through which prepared samples can be metered and an independent second element having an external envelope suited to acquisition of optical parameters from formed bodies in such suspensions, the second element being conforming and alignable to the first element so that non-axisymmetric refractive effects on optical characterizing parameters of formed bodies passing through the flow channel in the first element may be minimized before the two elements are optically joined and fixed in working spatial relationship.

Abstract: An improved optical flow cell adapted for use in a flow cytometer for differentiating formed bodies (e.g., blood cells) in liquid suspensions. Preferably manufactured by assembling, aligning, and optically joining at least two elements made from transparent material, the improved flow cell has a seamless internal flow channel of preferably non-circular cross-section in a cylindrical first element through which prepared samples can be metered and an independent second element having an external envelope suited to acquisition of optical parameters from formed bodies in such suspensions, the second element being conforming and alignable to the first element so that non-axisymmetric refractive effects on optical characterizing parameters of formed bodies passing through the flow channel in the first element may be minimized before the two elements are optically joined and fixed in working spatial relationship.

Abstract: An improved optical flow cell adapted for use in a flow cytometer for differentiating formed bodies (e.g., blood cells) in liquid suspensions. Preferably manufactured by assembling, aligning, and optically joining at least two elements made from transparent material, the improved flow cell has a seamless internal flow channel of preferably non-circular cross-section in a cylindrical first element through which prepared samples can be metered and an independent second element having an external envelope suited to acquisition of optical parameters from formed bodies in such suspensions, the second element being conforming and alignable to the first element so that non-axisymmetric refractive effects on optical characterizing parameters of formed bodies passing through the flow channel in the first element may be minimized before the two elements are optically joined and fixed in working spatial relationship.

Abstract: Systems and methods are provided for sensing and characterizing small particles, and in particular blood cells suspended in a liquid medium. Exemplary systems include a volumeter conduit having a central region of higher electrical resistivity disposed between a first and second distal region of lower electrical resistivity, and a current source and sensing circuit module in electrical connectivity with the first and second distal regions. The module provides an electrical excitation current to the first and second distal regions to establish a particle-sensitive zone within the conduit, and detects current changes occasioned by particles of the biological sample passing through the particle-sensitive zone.

Abstract: An improved optical flow cell adapted for use in a flow cytometer for differentiating formed bodies (e.g., blood cells) in liquid suspensions. Preferably manufactured by assembling, aligning, and optically joining at least two elements made from transparent material, the improved flow cell has a seamless internal flow channel of preferably non-circular cross-section in a cylindrical first element through which prepared samples can be metered and an independent second element having an external envelope suited to acquisition of optical parameters from formed bodies in such suspensions, the second element being conforming and alignable to the first element so that non-axisymmetric refractive effects on optical characterizing parameters of formed bodies passing through the flow channel in the first element may be minimized before the two elements are optically joined and fixed in working spatial relationship.

Abstract: Systems and methods are provided for sensing and characterizing small particles, and in particular blood cells suspended in a liquid medium. Exemplary systems include a volumeter conduit having a central region of higher electrical resistivity disposed between a first and second distal region of lower electrical resistivity, and a current source and sensing circuit module in electrical connectivity with the first and second distal regions. The module provides an electrical excitation current to the first and second distal regions to establish a particle-sensitive zone within the conduit, and detects current changes occasioned by particles of the biological sample passing through the particle-sensitive zone.

Abstract: An improved optical flow cell adapted for use in a flow cytometer for differentiating formed bodies (e.g., blood cells). Manufactured from a monolithic transparent material, the improved flow cell has an internal flow channel of polygonal transverse cross-section through which prepared samples can be metered and an external envelope suited to acquisition of optical parameters from formed bodies in such samples. Preferably, such flow cell is formed by a glass-drawing process in which a relatively large glass preform having a rectilinear internal channel of a desired polygonal cross-sectional shape is heated and drawn to achieve a desired cross-sectional area of reduced size. Also disclosed are preferred methods for differentiating formed bodies using the flow cell of the invention.

Abstract: An improved optical flow cell adapted for use in a flow cytometer for differentiating formed bodies (e.g., blood cells). Manufactured from a monolithic transparent material, the improved flow cell has an internal flow channel of polygonal transverse cross-section through which prepared samples can be metered and an external envelope suited to acquisition of optical parameters from formed bodies in such samples. Preferably, such flow cell is formed by a glass-drawing process in which a relatively large glass preform having a rectilinear internal channel of a desired polygonal cross-sectional shape is heated and drawn to achieve a desired cross-sectional area of reduced size. Also disclosed are preferred methods for differentiating formed bodies using the flow cell of the invention.

Abstract: The present invention provides an improved a-Si:H photoreceptor comprising a-Si:H photoconductors and conductive substrates, such as metallic members or plastic members provided with a metallic or an ohmic layer, in which degrading effects of the ambient environment on the electrophotographic properties of the a-Si:H photoconductor is minimized. The present invention also provides a cost-effective method of forming the improved a-Si:H photoreceptors. The method comprises stabilizing an a-Si:H photoreceptor member against environmental degradation of its photoconductive properties, by modifying the working surface of the photoconductor through treatment with a silanol solution. The clean annealed photoreceptor is preferably exposed to a freshly prepared aqueous mixture of an organosilane hydrolyzable to yield a silanol solution. The photoreceptor is then rinsed with water to remove vagrant oligomers formed during condensation of the silanol prepolymers but unattached to surface sites on the photoconductor.

Abstract: A new photoreceptor is provided which comprises a conductive substrate and a photoconductive layer of 5 micra or less in thickness on the substrate. The photoreceptor has a dark decay greater than 20 seconds and contains less than 5% total hydrogen. The substrate is selected from the group consisting of alloys of aluminum, chromium, iron, molybdenum, nickel or tungsten. In addition, the substrate can be a nonconductive material, such as plastic, provided with an electrically conductive layer. A new method for making the improved photoreceptor comprises providing a conductive substrate and forming a photoconductive layer of 5 micra or less in thickness on said substrate by depositing an amorphous material containing silicon and hydrogen atoms wherein said substrate has a negative potential between −40 and −100 volts during the forming of said layer.

Abstract: Apparatus for sensing and characterizing particles (e.g., blood cells or ceramic powders) suspended in a liquid medium comprises a conduit through which the particle suspension is caused to pass simultaneously with an electrical current. According to the invention, the interior wall of the conduit effectively varies in resistivity along the length of the conduit to define a delimited central region of high electrical resistivity which is smoothly contiguous on its opposing boundaries to uninsulated distal elements of lesser electrical resistivity. The delimited central region of the conduit functions as a Coulter volumeter conduit. The uninsulated distal elements of the conduit are made to have a dimension along the conduit wall which is at least equal to the axial extent of the effective ambit electric fields of a traditional Coulter volumeter conduit having a cross-sectional geometry identical to that of the delimited central region of high resistivity in the improved volumeter conduit.