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 Input:
Abstract: Cardiac output was measured 120 times in 27 critically ill patients using the thermodilution and transthoracic electrical impedance methods. Both the minimum and mean values for the distance between the inner electrodes, and a variety of values for the resistivity of blood (rho) were substituted in the Kubicek's empiric formula for calculating cardiac output by transthoracic electrical impedance. Using the mean distance between the inner electrodes and a rho-value of 150 ohm X cm gave the best agreement between the methods (mean difference 0.17 +/- 2.4 L/min). Ventilation alone or with positive end-expiratory pressure did not significantly affect the bias of the estimate, but both affected its precision when compared with measurements in spontaneously breathing patients (SD of mean difference 2.4 and 3.2 L/min, respectively, vs. 1.5 L/min). The pulmonary artery wedge pressure was significantly higher in patients with an abnormal diastolic impedance waveform (zero-wave), but there was no relationship between wedge pressure and base impedance per unit length between the measuring electrodes.

Ex Output:
Adult

Ex Input:
Abstract: An orientated substratum has been implicated in the development and regeneration of axons and synapses. We prepared a basement membrane matrix from autogenous striated muscle, used it to repair the sciatic nerve in rats, then investigated the results by histology and electrophysiology. When treated grafts were coaxially aligned with the nerve fascicles functional recovery appeared within 30 days, with good growth of axons into the distal nerve. Grafts with myotubes at right angles to the nerve fascicles supported nerve regeneration but at a slower rate. Grafts of coaxially aligned but untreated muscle allowed axon penetration only through naturally degenerated muscle fibres, with minimal axon penetration of the distal nerve. It is concluded that in the rat a treated graft with correctly orientated empty myotubes can facilitate and guide the regeneration of peripheral nerve after injury and so lead to recolonisation of the distal stump with functional recovery.

Ex Output:
Animal

Ex Input:
Abstract: The parameters of hematoporphyrin-derivative (HpD) photocytotoxicity of human glioma cells in cell culture were studied to determine the optimum wavelength and power density of light, to investigate the influence of tissue oxygenation, and to evaluate the role of singlet oxygen and free radicals in producing cell death. Cell survival curves demonstrated a relative killing efficiency of 12:1 for violet compared to red light. Eighty joules of red light were required to produce 100% cell kill at an HpD concentration of 10 micrograms/ml, a level of HpD that has been quantitated in biopsies from patients receiving HpD photoradiation therapy. No difference in cellular killing efficiency was observed for power densities of red light varying from 10 to 100 mW/cm2. Cytotoxicity was directly related to O2 tension from 12 to 490 torr with a slight but consistent increase in cell kill at O2 tensions from 7 to 12 torr. Cytotoxicity was effectively quenched by beta-carotene, whereas mannitol had no effect, indicating that cytotoxicity is probably mediated via a mechanism involving singlet oxygen. This information may serve as a basis for more effective application of HpD photoradiation therapy and for designing protocols to study the efficacy of such therapy.

Ex Output:
Cell Line