Abstract: Cell lines useful for analysis of human homologous interchromosomal recombination are described. The cell lines carry endogenous mutant alleles of a selectable gene and can regenerate a selectable phenotype through homologous genetic recombination but not by large deletion of nucleotides or by chromosome loss. Assays using the cell lines permit quantitative and qualitative analysis of recombination events which occur between human chromosomes in somatic cells in culture. The assay relies on normal genes in their normal chromosomal site. The assays can be used to test for environmental agents which induce homologous recombination in human cells.

Abstract: A hinge is described having first and second members for respective attachment to two components to be hingedly interconnected. A movement arrestor is provided which serves as a check on the hinging movement of the two hinge members. The arrestor comprises a cam surface on the first hinge member and a roller mounted on the second hinge member. The roller is resiliently displaceable relative to the second member to force the roller into engagement with the cam surface so as to provide the desired check. In accordance with the invention the roller includes a polymer sleeve with which it engages the cam surface, to absorb and thereby reduce the noise and to reduce the wear produced as the roller moves over the cam surface as the hinge is opened and closed. The sleeve material may be PTFE or Nylon and may be snap fitted over the roller and may include an axial slot. The roller and cam surface are conveniently formed from metal.

Abstract: A hinge, particularly for a motor vehicle, comprises a hinge leaf 2 to which a hinge pin 4 is secured. The pin has a projecting end over which a bearing sleeve 8 tightly fits, the end of the pin and sleeve being receivable in a journal of a second hinge leaf 14. The sleeve 8 preferably incorporates a thrust washer 12, which may be integral with the sleeve to form a bush. The washer bears against a shoulder 6 formed on the pin and which abuts the leaf 2.

Abstract: A friction clutch driven plate comprises a hub having a fixed hub flange and an auxiliary hub flange which can rotate a limited amount relative to the hub. Bob weights can move radially under centrifugal force against return springs to engage apertures in the auxiliary hub flange and lock the hub flanges together. This reduces the effective length of spring windows in the hub flanges and the range of movement permitted by a low rate spring which damps gearbox rattle when in neutral.