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

Example Input: Abstract: Published normal histomorphometric data were used to derive distributions of thicknesses of trabecular plates and completed bone remodelling units (the basic multicellular unit carrying out bone remodelling, the BMU, when completed is termed a structural unit BSU). A stochastic model was set up to investigate the predictions of current BMU theory. Each of 100 trabecular "thicknesses" was drawn from the appropriate normal distribution using a pseudorandom number generator. Each day, each of its two surfaces when quiescent was assumed to have a 1:900 chance of initiating a remodelling cycle. Resorption (active, 12 days; reversal phase, 27 days) was followed by formation (94 +/- 35 days) and resulted in BMU balance when resorption depth was 36.8 +/- 9.2 micron. Fenestration (thickness less than 0) was assumed to lead to permanent loss of the trabecula. The original model unrealistically increased its mean trabecular thickness as thin trabeculae were lost. This was corrected by assuming that thin trabeculae had greater osteoblastic stimulation and a consequent tendency to thicken, perhaps due to higher mechanical loading. Over 20 years, 14% of trabeculae were lost when the BMU balance was exact and the distribution of trabecular thicknesses was unchanged. About one-half of fenestrations were due to deeper-than-average resorption cavities developing in thin trabeculae, and the remainder to coincident remodelling on both surfaces. A 10% fall in osteoblast lifespan resulted in an additional 36.7% loss of trabecular bone volume and mean trabecular thickness fell to 83.1 micron, compatible with Courpron's data. Simulating more rapid mechanisms of bone loss, approximately 50% of trabeculae could be lost after ten years by the arrest of bone formation; the doubling of resorption depth with unchanged bone formation; and a doubling in the rate of initiation of new BMUs with unchanged bone formation rate, all three followed by complete recovery of BMU balance after only two years. In each case, mean trabecular thickness fell only transiently but trabeculae continued to be lost after recovery. Prolonged osteoblast life span was the most likely explanation for the increased mean trabecular thicknesses and trabecular bone volumes seen in patients with osteoporosis, when treated with sodium fluoride plus calcium supplements or daily injections of parathyroid peptide hPTH 1-34.
Example Output: A stochastic analysis of iliac trabecular bone dynamics.

Example Input: Abstract: The role of optimal placement of electrodes and mode of shock delivery from a defibrillator was examined in dogs with and without myocardial infarction. Single, double and triple truncated exponential shocks separated by 1 ms were delivered through various electrode combinations and cardiac vectors after electrical induction of ventricular fibrillation. A single shock through a pathway not incorporating the interventricular septum (catheter electrodes or epicardial patches between anterior and posterior left ventricle) required the highest total energy (22.6 and greater than 26.4 J, respectively) and peak voltage (1,004 and greater than 1,094 V, respectively) to terminate ventricular fibrillation. A single shock through a pathway including the interventricular septum required lower total energy and peak voltage to defibrillate. Combinations of two sequential shocks between an intracardiac catheter electrode and anterior left ventricular epicardial patch, between the catheter electrode and subcutaneous extrathoracic plate and between three ventricular epicardial patches all significantly reduced total energy (7.7, 8.7 and 7.8 J, respectively) and peak voltage (424, 436 and 424 V, respectively) needed to defibrillate. Three sequential shocks exerted no significant additional reduction in total energy of the defibrillation threshold than did two sequential shocks. Infarcted canine heart required less peak voltage but not total energy to terminate ventricular fibrillation than did noninfarcted heart. Therefore, two sequential shocks over different pathways reduce both total energy and peak voltage required to terminate ventricular fibrillation.
Example Output: Double and triple sequential shocks reduce ventricular defibrillation threshold in dogs with and without myocardial infarction.

Example Input: Abstract: Forty-two brothers, 66 dizygotic twins of both sexes and 106 monozygotic twins of both sexes, 16 to 34 yr of age, took part in this study that was designed to investigate the effect of heredity in aerobic performance. Maximal oxygen uptake (VO2 max), maximal heart rate (HR max), maximal ventilation, and maximal oxygen pulse were obtained from a progressive ergocycle test to exhaustion. Total work output in a 90-min maximal ergocycle test was also determined in the twins. Fat-free weight was estimated from body density measurements obtained through underwater weighing. Aerobic performance scores were adjusted for age (brothers), and age and sex (dizygotic and monozygotic twins) by regression procedures. Dizygotic twins and brothers of same sibship exhibited about the same level of resemblance for all variables or were only slightly different, with the exception of HR max. Monozygotic pairs were generally more alike than the other sibs, as suggested by the intra-class coefficients. Twin data were used to compute the genetic effects. The within-pair estimate of genetic variance revealed that it was significant (P less than or equal to 0.05) for all variables except VO2 max X kg-1 fat-free weight X min-1. In the case of HR max, the among-pairs component estimate had to be used, and it also proved significant (P less than or equal to 0.01). The size of the genetic effect was computed from three different methods, and it reached about 40% for VO2 max X kg-1 X min-1, 50% for HR max, 60% for maximal oxygen pulse and maximal ventilation, and 70% for 90-min work output X kg-1.(ABSTRACT TRUNCATED AT 250 WORDS)
Example Output:
Aerobic performance in brothers, dizygotic and monozygotic twins.