Given an abstract of a paper, generate a title for this paper such that conveys the key focus of the paper.

Example Input: Abstract: The relationship between the perfusion flow rate and cerebral oxygen consumption during deep hypothermic cardiopulmonary bypass at 20 degrees C was investigated in dogs. In 10 dogs the perfusion flow rate was decreased in steps from 100 to 60, 30, and 15 ml/kg/min every 30 minutes. Although cerebral blood flow decreased as perfusion flow rate decreased, the ratio of cerebral blood flow to the perfusion flow rate increased significantly (p less than 0.05) at a perfusion flow rate of 15 ml/kg/min compared to that at a perfusion flow rate of 100 or 60 ml/kg/min. The arterial-sagittal sinus blood oxygen content difference increased as perfusion flow rate decreased. Consequently, cerebral oxygen consumption did not vary significantly at perfusion flow rates of 100 (0.48 +/- 0.10), 60 (0.43 +/- 0.14), and 30 ml/kg/min (0.44 +/- 0.12 ml/100 gm/min), and it decreased significantly to 0.31 +/- 0.22 ml/100 gm/min at a perfusion flow rate of 15 ml/kg/min. In five dogs the perfusion flow rate was decreased in one step from 100 to 15 ml/kg/min, and after 60 minutes' perfusion at a perfusion flow rate of 15 ml/kg/min, the perfusion flow rate was returned to 100 ml/kg/min. Cerebral oxygen consumption decreased significantly during 60 minutes' perfusion at a perfusion flow rate of 15 ml/kg/min and did not return to its initial value after the perfusion flow rate was returned to 100 ml/kg/min. These data indicate that the optimal perfusion flow rate for the brain during deep hypothermic cardiopulmonary bypass at 20 degrees C appears to be 30 ml/kg/min, with a possible oxygen debt in the brain resulting in anaerobic metabolism if the perfusion flow rate is kept at 15 ml/kg/min or less.
Example Output: Optimal perfusion flow rate for the brain during deep hypothermic cardiopulmonary bypass at 20 degrees C. An experimental study.

Example Input: Abstract: Low nanogram and picogram quantities of cocaine metabolite equivalents were detected in extracts from perspiration stains, menstrual bloodstains, and hair using radioimmunoassay. The theory of drug inclusion in hair and its significance are discussed.
Example Output: Detection of cocaine metabolite in perspiration stain, menstrual bloodstain, and hair.

Example Input: Abstract: The bowed appearance of the lower extremities is most often caused by internal rotation of the tibia in relationship to the femur. It is most commonly seen as the infant commences ambulation. This so-called physiologic bowing usually spontaneously resolves with growth and the maturity of the lower extremities. In older children, tibia varum may occur, in which there is a local arrest of growth on the posterior medial aspect of the tibia producing a true structural angulation. In certain long-standing metabolic or genetic bone disorders, the effects of weight bearing produce a true bowing of the extremities with changes about the hips, knees, and ankles. The most important aspect in the evaluation of a child with a bowed appearance of the lower extremities is to determine which conditions require aggressive treatment and which ones require simply giving the parents reassurance that the condition will spontaneously regress.
Example Output:
Bowlegs.