Given an abstract, indicate which of the provided candidate titles (Option1 and Option2) best describes it (respond with the text of the title, not option1/2).

Abstract: Daily human energy requirements calculated from separate components of energy expenditure are inaccurate and usually in poor agreement with measured energy intakes. Measurement of energy expenditure over periods of 24 h or longer is needed to determine more accurately rates of daily energy expenditure in humans. We provide a detailed description of a human respiratory chamber and methods used to determine rates of energy expenditure over 24-h periods in 177 subjects. The results show that: fat-free mass (FFM) as estimated by densitometry is the best available determinant of 24-h energy expenditures (24EE) and explains 81% of the variance observed between individuals (24EE [kcal/d] = 597 + 26.5 FFM); 24EE in an individual is very reproducible (coefficient of variation = 2.4%); and even when adjusted for differences in FFM, there is still considerable interperson variability of the daily energy expenditure. A large portion of the variability of 24EE among individuals, independent of differences in body size, was due to variability in the degree of spontaneous physical activity, i.e., "fidgeting," which accounted for 100-800 kcal/d in these subjects.
Which is the apt title for the abstract? option1: Determinants of 24-hour energy expenditure in man. Methods and results using a respiratory chamber. option2: Hematologic data in the case records [letter]
Determinants of 24-hour energy expenditure in man. Methods and results using a respiratory chamber.

Abstract: Today, echocardiography enjoys a prominent place in the physician's diagnostic armamentarium. Its safe application, accuracy, and reproducibility have made its widespread use popular. The ability of echocardiography to visualize cardiac valves, intracardiac masses, and ventricular wall motion is unique. This article highlights the applications of echocardiography from the physician's vantage point.
Which is the apt title for the abstract? option1: Clinician's approach to echocardiography. option2: Total arm flap: an alternative method of chest-wall reconstruction [letter]
Clinician's approach to echocardiography.

Abstract: Human decompression sickness is presumed to result from excess inert gas in the body when ambient pressure is reduced. Although the most common symptom is pain in the skeletal joints, no direct study of nitrogen exchange in this region has been undertaken. For this study, nitrogen tagged with radioactive 13N was prepared in a linear accelerator. Nine human subjects rebreathed this gas from a closed circuit for 30 min, then completed a 40- to 100-min washout period breathing room air. The isotope 13N was monitored continuously in the subject's knee during the entire period using positron detectors. After correction for isotope decay (half-life = 9.96 min), the concentration in most knees continued to rise for at least 30 min into the washout period. Various causes of this unexpected result are discussed, the most likely of which is an extensive redistribution of gas within avascular knee tissues.
Which is the apt title for the abstract? option1: Nitrogen gas exchange in the human knee. option2: Patient and house officer attitudes on physician attire and etiquette.
Nitrogen gas exchange in the human knee.