Relationship between the heart rate and E/A ratio in athletic and non-athletic males in different ages

Introduction: One of the most important effects of regular physical training is the adaptation of the cardiovascular system. The basic importance of the “athlete’s heart” is manifested in two fields, one is the public health, the second is the competitive sport. The aim of the present study is to clarify whether the higher E/A quotient of athletes is a favorable change in the intrinsic relaxation properties of the left ventricle. Question: The higher E/A quotient of physically active persons can be explained by the training bradycardia, or it can be supposed as an independent effect of regular physical exercise? Methods: Peak early (E) and atrial blood flow velocities (A) were assessed by Doppler echocardiography at rest in males (N=1237) the E` and A` were assessed by Tissue Doppler Imaging (TDI), (N=144) all the data were collected in Hungary, from 1993–2011. Relationship between E/A and resting heart rate (HR), was determined by linear regression analysis. Pearson correlation coefficients were used to express the connection between heart rate and the transmitral E/A and TDI determined E’/A’ quotients in 19-35 yr old males. Student t-test was used to establish the differences between transmitral and TDI determined velocities and indices in athletes and non-athletes. Results: The E/A decreased with age, the rate of decrease was slower in the physically trained subjects, except in children. In children, adolescent-young and young adult subjects E/A against HR equations of the athletic and non-athletic groups were similar, differences between the means were only due to the differences of the HR. In the 31–44 yr old males, the intercepts of the athletes’ regression lines were higher. The oldest (>44 yr) active subjects showed a significant regression while sedentary males did not. According to the results of TDI it seems that the disturbing effect of the heart rate is really stronger in case of the E/A while there was no significant correlation in the E’/A’ values. However, significant differences were seen both in E/A values and in TDI measurements of the medial part of the mitral valve (med. E’/A’) between athletes and non-athletes. Conclusions: The HR-independent beneficial effect of regular physical training on the diastolic function manifests itself at the older ages. According to our results, the long-term physical training (mainly endurance type) can diminish the age-associated impairment of diastolic function but the impact of resting HR should always be taken into consideration when assessing intergroup differences in the E/A ratio, especially when studying the effect of exercise training upon cardiac function

Solution Structures, Stabilities, Kinetics, and Dynamics of DO3A and DO3A–Sulphonamide Complexes

The Gd³⁺-DO3A–arylsulphonamide (DO3A–SA) complex is a promising pH-sensitive MRI agent. The stability constants of the DO3A–SA and DO3A complexes formed with Mg²⁺, Ca²⁺, Mn²⁺, Zn²⁺, and Cu²⁺ ions are similar, whereas the log<i>K</i>_LnL values of Ln­(DO3A–SA) complexes are 2 orders of magnitude higher than those of the Ln­(DO3A) complexes. The protonation constant (log<i> K</i>_MHL) of the sulphonamide nitrogen in the Mg²⁺, Ca²⁺, Mn²⁺, Zn²⁺, and Cu²⁺ complexes is very similar to that of the free ligand, whereas the log<i>K</i>_LnHL values of the Ln­(DO3A–SA) complexes are lower by about 4 log<i>K</i> units, indicating a strong interaction between the Ln³⁺ ions and the sulphonamide N atom. The Ln­(HDO3A–SA) complexes are formed via triprotonated *Ln­(H₃DO3A–SA) intermediates which rearrange to the final complex in an OH^–-assisted deprotonation process. The transmetalation reaction of Gd­(HDO3A–SA) with Cu²⁺ is very slow (<i>t</i>_1/2 = 5.6 × 10³ h at pH = 7.4), and it mainly occurs through proton-assisted dissociation of the complex. The ¹H and ¹³C NMR spectra of the La-, Eu-, Y-, and Lu­(DO3A–SA) complexes have been assigned using 2D correlation spectroscopy (COSY, EXSY, HSQC). Two sets of signals are observed for Eu-, Y-, and Lu­(DO3A–SA), showing two coordination isomers in solution, that is, square antiprismatic (SAP) and twisted square antiprismatic (TSAP) geometries with ratios of 86–14, 93– 7, and 94–6%, respectively. Line shape analysis of the ¹³C NMR spectra of La-, Y- , and Lu­(DO3A–SA) gives higher rates and lower activation entropy values compared to Ln­(DOTA) for the arm rotation, which indicates that the Ln­(DO3A–SA) complexes are less rigid due to the larger flexibility of the ethylene group in the sulphonamide pendant arm. The fast isomerization and the lower activation parameters of Ln­(DO3A–SA) have been confirmed by theoretical calculations in vacuo and by using the polarizable continuum model. The solid state X-ray structure of Cu­(H₂DO3A–SA) shows distorted octahedral coordination. The coordination sites of Cu²⁺ are occupied by two ring N- and two carboxylate O-atoms in equatorial position. The other two ring N-atoms complete the coordination sphere in axial positions. The solid state structure also indicates that a carboxylate O atom and the sulphonamide nitrogen are protonated and noncoordinated

Temperature Dependent Carrier Dynamics in Ga-Alloyed CdSe/ZnS Core–Shell Quantum Dots

In this work, temperature dependent transient absorption spectroscopy measurements are presented on gallium-alloyed CdSe/ZnS core–shell nanoparticles between 30 and 130 °C. To our knowledge, temperature dependent measurements in these systems have been reported only in a few papers, although all processes related to carrier recombination are affected by temperature. For these experiments, gallium-alloyed CdSe/ZnS QD samples were used with nominal doping percentages of 2.5%, 7.5%, 15%. The experimental results show that the transient absorption decay is faster for the pristine CdSe/ZnS samples than in the gallium-alloyed samples at all temperatures. It is assumed that Ga-alloying promotes the formation of trions in the samples by introducing occupied impurity levels within the bandgap of CdSe. The resulting Coulomb blockade will, in turn, prolong the hot-electron relaxation process. By variation of the temperature, the distribution of charge carriers in the different recombination channels can be altered to accelerate recombination in the Ga-alloyed samples at higher temperatures. These measurements demonstrated their usefulness for observing the redistribution of charge carriers among different relaxation pathways

Early stage litter decomposition across biomes

[Departement_IRSTEA]Territoires [TR1_IRSTEA]SEDYVINInternational audienceThrough litter decomposition enormous amounts of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order to understand the controls on the terrestrial carbon transfer to the atmosphere. However, previous studies were mostly based on site-specific litter and methodologies, adding major uncertainty to syntheses, comparisons and meta-analyses across different experiments and sites. In the TeaComposition initiative, the potential litter decomposition is investigated by using standardized substrates (Rooibos and Green tea) for comparison of litter mass loss at 336 sites (ranging fro