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: Between 1971 and 1980, the senior one of us (C.S.R.) performed 101 primary total hip replacements in eighty-five consecutive patients who were less than fifty-five years old. All of the patients had degenerative joint disease. Survivorship analysis was used to calculate a predicted cumulative rate of success for this series of total hip replacements over ten years of follow-up. This method of analysis of the data was chosen because it provides a prediction of the expected durability of a total hip arthroplasty in any individual patient. The need for revision because of loosening or infection or else radiographic evidence of migration of a component was the criterion for failure. Two revisions were performed for aseptic loosening of the acetabular component. One infection necessitated revision, and radiographic evidence of loss of fixation was seen in one additional acetabular component and one femoral stem. Life-table calculations predicted that the survivorship of all of the total hip replacements in this series would be 87.6 per cent at ten years of follow-up. Based on the results of the application of this method of analysis to the current series, we concluded that a primary cemented total hip replacement, when performed for coxarthrosis, can be expected to function durably in an active middle-aged patient.

Ex Output:
Actuarial Analysis

Ex Input:
Abstract: By use of an improved density measuring system, we found that the gravimetric density of arterial blood of dogs fluctuates at the same frequency as the spontaneous or mechanical ventilation. Similar density fluctuations were observed in the blood leaving isolated, perfused lobes of dogs that were ventilated cyclicly. Employing an analysis that balanced the erythrocyte and plasma flows through distensible capillaries containing blood with a tube hematocrit lower than the hematocrit in large blood vessels, we derived a relationship to estimate from the density fluctuation the change in pulmonary capillary blood volume (Vc). For mechanical ventilation, the maximum change in density over one ventilation cycle increased from 0.084 +/- 0.01 to 0.47 +/- 0.05 (SE) g/l as the frequency decreased from 29 to 6 cycles/min. These density changes were estimated to be the result of an 1-16% change in Vc. A larger tidal volume for the mechanical ventilation led to a larger density fluctuation. The maximum density change of spontaneous respiration of 6 cycles/min was one-sixth of the mechanical case, indicating a much smaller change in Vc during spontaneous respiration. When the airway flow resistance was increased for spontaneous respiration, larger density fluctuations were observed.

Ex Output:
Airway Resistance

Ex Input:
Abstract: The effects of parental smoking on IgE and IgD levels in cord serum and subsequent infant allergy were investigated in an unselected series of 186 European newborn infants. Maternal smoking caused a significant rise in both IgE (p less than 0.05) and IgD (p less than 0.05), a finding that was most apparent in newborn infants with a negative biparental history of allergy (p less than 0.025 and p = 0.005, respectively). Furthermore, newborn infants of nonallergic parents had a more than threefold (p less than 0.01) higher incidence of elevated cord IgE (greater than or equal to 1.20 IU/ml) and a fourfold (p = 0.005) higher risk of developing definite or probable atopic disease before 18 months of age if the mother smoked than if she did not. Paternal smoking did not influence, in whatever the subgroup, cord IgE or subsequent infant allergy but increased cord IgD (p less than 0.001) among newborn infants with a negative family history even after controlling for maternal smoking (p less than 0.04). These results suggest that parental smoking in some way affects the fetal immune system, probably via substances in tobacco smoke. Maternal smoking in particular appears to exert a pronounced effect on the IgE system already in fetal life, predisposing even "low-risk" infants to subsequent sensitization, probably in synergy with a later acquired mucosal damage that would facilitate penetration of foreign matter. Pregnant women and mothers should be encouraged to try and give up smoking that might help to prevent allergic disease in their infants.

Ex Output:
Female