Abstract: A hands-free gripping device which holds generally cylindrical containers, particularly labware, securely and prevents the container from turning while either opening or closing it. The gripping device features internal deformable ribbing, which secures the container by canting slightly when the container is turned thereby wedging the container in place. This action resists rotation in either direction, making a single device practical for both opening and closing. The device can be mounted on any flat surface and acts as a "third hand" to allow the user to use both hands or to use a single hand to grasp securely the closure being removed or secured from the container. The gripping device facilitates assembly or disassembly of labware devices needing application of torque.

Abstract: A centrifuge rotor and method for gradient density separation which supports a generally cylindrical volume of sample solution with its axis inclined to the spin axis at an angle which is optimized for maximum separation efficiency while reducing contamination by undesirable centrifugates upon reorientation of the desirable centrifugates. The optimum angle is determined based on the relationship .theta.=Tan.sup.-1 (D/15L).sup.0.5 where D and L are respectively the diameter and length of the cylindrical volume of the sample solution and .theta. is the angle of inclination.

Abstract: Halogenated dibenzazepines, particularly flouro- or iododesmethylimipramine, find use for measuring regional blood flows and for retention in particular organs for radioactive imaging. Such compositions are introduced into the arterial flow leading to the organ, and the compositions bind to the organ as a result of interaction with cellular receptors. The compositions have been found to display very high retention rates in the organ for relatively long periods of time.

Abstract: A centrifuge rotor and method for gradient density separation which supports a generally cylindrical volume of sample solution with its axis inclined to the spin axis at an angle which is optimized for maximum separation efficiency while reducing contamination by undesirable centrifugates upon reorientation of the desirable centrifugates. .Iadd.The sample solution is contained in a centrifuge tube which is closed at its top end by a top portion which is supported by a support cap. The undesirable centrifugates are pelleted to the end corners of the inclined centrifuge tube. The rotor and method are particularly adapted, for example, for separation of nucleic acid into plasmid DNA and chromosomal DNA by density gradient centrifugation. .Iaddend.The optimum angle is determined based on the relationship .theta.=Tan.sup.-1 (D/15L).sup.0.5 where D and L are respectively the diameter and length of the cylindrical volume of the sample solution and .theta. is the angle of inclination.