Peak cardiac power output and cardiac reserve in sedentary men and women

Background and Purpose: Cardiac power output (CPO) and cardiac reserve (CR) are novel parameters of overall cardiac function. The purpose of this study was to determine differences in values of the CPO at rest and peak exercise and CR in sedentary men and women. Material and Methods: Thirty healthy men (age 21.2±0.7 years, body mass 63±6.3 kg, height 168.3±5.1 cm) and thirty healthy women (age 21.3±1.9 years, mass 82.5±7.9 kg, height 181.9±4.9 cm) were included in this study. Echocardiography was used to assess cardiac and hemodynamic parameters. CPO was calculated, at rest and after performed maximal bicycle test, as the product of cardiac output and mean arterial pressure, and CR as the difference of CPO value measured at peak exercise and at rest. Results: At rest, the two groups had similar values of cardiac power output (1.04±0.3W versus 1.14±0.25W, p>0.05). CPO after peak exercise was higher in men (5.1±0.72W versus 3.9±0.58W, p<0.05), as was cardiac reserve (3.96±0.64W versus 2.86±0.44W, p<0.05), respectively. After allometric scaling method was used to decrease the effect of body size on peak CPO, men still had significantly higher peak CPO (2.79±0.4 W m-2 versus 2.46±0.32 W m-2, p<0.05). At peak exercise, a significant positive relationship was found between cardiac power output and end diastolic volume (r=0.60), end diastolic left ventricular internal dimension (r=0.58), stroke volume (r=0.86) and cardiac output (r=0.87). Conclusion: The study showed that men had higher CPO after peak exercise and greater cardiac reserve than women, even after decreasing body size effect

RNA interference in Lepidoptera: an overview of successful and unsuccessful studies and implications for experimental design

A

Ubx Regulates Differential Enlargement and Diversification of Insect Hind Legs

Differential enlargement of hind (T3) legs represents one of the hallmarks of insect evolution. However, the actual mechanism(s) responsible are yet to be determined. To address this issue, we have now studied the molecular basis of T3 leg enlargement in Oncopeltus fasciatus (milkweed bug) and Acheta domesticus (house cricket). In Oncopeltus, the T3 tibia displays a moderate increase in size, whereas in Acheta, the T3 femur, tibia, and tarsus are all greatly enlarged. Here, we show that the hox gene Ultrabithorax (Ubx) is expressed in the enlarged segments of hind legs. Furthermore, we demonstrate that depletion of Ubx during embryogenesis has a primary effect in T3 legs and causes shortening of leg segments that are enlarged in a wild type. This result shows that Ubx is regulating the differential growth and enlargement of T3 legs in both Oncopeltus and Acheta. The emerging view suggests that Ubx was co-opted for a novel role in regulating leg growth and that the transcriptional modification of its expression may be a universal mechanism for the evolutionary diversification of insect hind legs

New String Reconfiguration Technique for Residential Photovoltaic System Generation Enhancement

Improvement of photovoltaic (PV) power plant performance under partial shading conditions aiming to increase electrical energy generation is in the focus of this research. This paper proposes the performance optimization of PV power plant under partial shading conditions by new PV string reconfiguration technique. The Matlab/Simulink model is used to simulate the operation of the PV string under partial shading conditions and with the proposed recombination technique. Simulated operational conditions have experimentally been verified by string characteristics measurement on the existing roof-top PV system at the Faculty of Technical Sciences in Novi Sad. Simulation and experimental results showed a high degree of matching, while the obtained values proved that proposed method leads to output power increase and higher PV system generation in PV string operation under partial shading