Atrial natriuretic peptides are a family of hormones synthesized within the same prohormone secreted mainly within the atrium of the heart. These peptides correlate inversely with blood pressure (BP) in humans throughout the day. The increase in BP with increasing age could thus be associated with a decrease in these hormones as the person ages. The present investigation was designed to determine if these peptides, i.e., long acting natriuretic peptide (LANP), vessel dilator (VSDL) and atrial natriuretic factor (ANF), exhibit differing circadian characteristics in men as a function of age. The LANP, VSDL, and ANF were obtained from blood sampled every 3-hr for 24-hrs in men housed in a hospital setting at 3 different ocassions, 5 years apart. Seven men were studied 3 times; 4 in 2 ocassions, and 4 participated once. BP was always obtained by ambulatory monitoring at 15-min intervals. Lights were off at 22:30 h and on at 06:30 h. Hospital meals (2400 cal) were served at 16:30, 07:30 and 13:30 h. Circadian characteristics of hormones and BP in groups of subjects divided by age (<55, 19 profiles; and >55 years, 14 profiles) were established by population multiple-component analysis [Fernández JR, Hermida RC. Chronobiol Internat 1998;15:191–204]. A significant high amplitude rhythm (P < 0.001) was demonstrated for the three peptides in each age-group, with highest values consistently obtained at about 05:30 h. Significant declines in daily mean and amplitude (P < 0.005) were noted in the older group for all three peptides. A highly significant inverse correlation was found between the values of the three peptides and systolic and diastolic BP (P < 0.007). LANP, VSDL, and ANF exhibit a highly significant circadian variation as well as a significant decline with age. The present findings indicate that these BP lowering hormones are present in high concentrations in the early morning hours and in significantly lower concentrations throughout the day, in keeping with their inverse relation with BP.
We report the formation of copper nanoparticles with various morphologies and low polydispersity, using Au nanoparticles as templates. This seeded growth strategy is based on the reduction of Cu2+ with hydrazine in water at low temperature. Additionally, the use of poly(acrylic acid) as capping agent allows synthesis under aerobic conditions. The dimensions of the resulting Au@Cu nanoparticles can be readily tuned through either the dimensions of the Au cores or the Cu/Au molar ratio. Although Au and Cu show a significant lattice mismatch, epitaxial growth of Cu onto single crystal Au nanorods was confirmed through high-resolution electron microscopy and electron diffraction analysis. The effects of core morphology on the optical properties of the core–shell nanoparticles were analyzed by vis-NIR spectroscopy and were found to agree with simulations based on the boundary element method. This work contributes to understand the strong effect of interband transitions on the optical response of Au@Cu and to confirm the importance of tuning the localized surface plasmon resonance away from the interband transitions.
PartitionTest test suite
A single nanoplatform integrating laser-induced heat generation by gold nanoparticles and temperature sensing up to 2000 K via (Gd,Yb,Er)2 O3 nanorods is demonstrated, which presents considerable potential for nanoscale photonics and biomedicine. Blackbody emission is ascertained from the temperature increment with AuNP concentration, emission color coordinates as a function of the laser pump power, and Planck's law of blackbody radiation.
Androstenedione is a steroidal hormone produced in male and female gonads, as well as in the adrenal glands, and it is known for its key role in the production of estrogen and testosterone. Androstenedione is also sold as an oral supplement, that is being utilized to increase testosterone levels. Simply known as “andro” by athletes, it is commonly touted as a natural alternative to anabolic steroids. By boosting testosterone levels, it is thought to be an enhancer for athletic performance, build body muscles, reduce fats, increase energy, maintain healthy RBCs, and increase sexual performance. Nevertheless, several of these effects are not yet scientifically proven. Though commonly used as a supplement for body building, it is listed among performance-enhancing drugs (PEDs) which is banned by the World Anti-Doping Agency, as well as the International Olympic Committee. This review focuses on the action mechanism behind androstenedione’s health effects, and further side effects including clinical features, populations at risk, pharmacokinetics, metabolism, and toxicokinetics. A review of androstenedione regulation in drug doping is also presented.
Phylogenetic networks aim to represent the evolutionary history of taxa. Within these, reticulate networks are explicitly able to accommodate evolutionary events like recombination, hybridization, or lateral gene transfer. Although several metrics exist to compare phylogenetic networks, they make several assumptions regarding the nature of the networks that are not likely to be fulfilled by the evolutionary process. In order to characterize the potential disagreement between the algorithms and the biology, we have used the coalescent with recombination to build the type of networks produced by reticulate evolution and classified them as regular, tree sibling, tree child, or galled trees. We show that, as expected, the complexity of these reticulate networks is a function of the population recombination rate. At small recombination rates, most of the networks produced are already more complex than regular or tree sibling networks, whereas with moderate and large recombination rates, no network fit into any of the standard classes. We conclude that new metrics still need to be devised in order to properly compare two phylogenetic networks that have arisen from reticulating evolutionary process.
