Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.

[EX Q]: Abstract: The selection of assessment procedures for the preclinical evaluation of haemosorbents and the relationship between such procedures and the intended application are exemplified by examination of the design and utilization of procedures based on the rat. Procedures are described for haemoperfusion and for membrane plasma separation followed by on-line sorbent treatment of plasma (plasma perfusion). These procedures are suitable for single or repeated use, with the animal in an unrestrained and conscious state. The relevance to the intended application is demonstrated with respect to artificial liver support by the ability of rat extracorporeal circuits to provide information on the relationship between sorbent properties and liver regeneration as determined by the proliferative response following partial hepatectomy.
[EX A]: Adsorption

[EX Q]: Abstract: Using roentgen stereophotogrammetric analysis (RSA), the integrity of the bond between the tibial component and the tibia was studied in seven knees, implanted with a cemented Kinematic total knee prosthesis for gonarthrosis. Migration ranging from 0.3 to 1.9 mm over a two-year period occurred in all seven cases. Displacement, induced by external forces, ranging from 0.2 to 1.0 mm was observed in five cases. Measurable migration and inducible displacement may be the rule rather than an exception in total knee arthroplasty (TKA). Accordingly, absolute rigid fixation would not be necessary for successful function of a TKA.
[EX A]: Aged

[EX Q]: Abstract: The posterior cell layer of the normal human cornea or "endothelium" was investigated by electron microscopy and immunocytochemistry. Ultrastructurally, the cells lacked the characteristic marker for endothelial cells (Weibel-Palade body). Immunoperoxidase studies demonstrated these cells to be negative for factor VIII antigen, but strongly positive for keratine, vimentin, S-100 protein, and neuron-specific enolase. The anterior epithelial cell layer showed identical immunoreactivity. These studies strongly suggest that the posterior cell layer of the cornea lacks ultrastructural and immunocytochemical markers of endothelial cells and both the anterior and posterior cell layers share similar cell markers. The authors propose that the posterior cell layer of the cornea should, therefore, not be misnamed as "endothelium."
[EX A]:
Cells