Atherogenic, hemostatic, and other potential risk markers in subjects with previous isolated myocardial infarction compared with long-standing uncomplicated stable angina

BACKGROUND: Several atherogenic, hemostatic, inflammatory, and genetic parameters and markers have been implicated as risk factors in coronary artery disease, although whether they are risk factors for acute as opposed to chronic coronary disease is unclear. METHODS AND RESULTS: Fifty subjects with an isolated myocardial infarction >3 months previously were compared with 50 subjects with a minimum 3-year history of stable angina, documented coronary artery disease, normal electrocardiogram and normal ventricular wall motion, and no episode suggesting infarction or unstable angina. Biologic variables analyzed included apolipoprotein B (apo B), lipoprotein (a), C-reactive protein (CRP), fibrinogen, factor VII, tissue plasminogen activator (TPA) and inhibitor (PAI-1), thrombin-antithrombin (TAT), fragment 1+2 (F1+2), von Willebrand factor (vWF), activated protein C resistance, homocyst(e)ine, anticardiolipin antibodies, blood group, and the angiotensin-converting enzyme insertion/deletion (I/D) and angiotensin II receptor gene polymorphisms. There were no significant differences between the 2 groups for any of the variables studied, although fibrinogen and F 1+2 tended to be slightly higher in the angina group (P = .09 for each). These significant correlations were present: age with fibrinogen, homocyst(e)ine, and vWF; factor VII with apo B, homocyst(e)ine, and TPA; apo B with TPA and CRP; CRP with fibrinogen, TPA, PAI-1, and factor VII; fibrinogen with vWF. CONCLUSIONS: Examination of atherogenic, hemostatic, inflammation, and genetic variables in the clinically quiescent state permitted no distinction between subjects with a previous isolated myocardial infarction in contrast to those with long-standing uncomplicated stable angina, favoring the notion that acute coronary events occur at random on a varying background of atherosclerosis. The multiple correlations found among these variables also underscore their complex interaction in the atherosclerotic process.     

Impact of the guanidinium group on hybridization and cellular uptake of cationic oligonucleotides

The grafting of cationic groups to synthetic oligonucleotides (ONs) in order to reduce the charge repulsion between the negatively charged strands of a duplex or triplex, and consequently to increase a complex's stability, has been extensively studied. Guanidinium groups, which are highly basic and positively charged over a wide pH range, could be an efficient ON modification to enhance their affinity for nucleic acid targets and to improve cellular uptake. A straightforward post-synthesis method to convert amino functions attached to ONs (on sugar, nucleobase or backbone) into guanidinium tethers has been perfected. In comparison to amino groups, such cationic groups anchored to alpha-oligonucleotide phosphoramidate backbones play important roles in duplex stability, particularly with RNA targets. This high affinity could be explained by dual recognition resulting from Watson-Crick or Hoogsteen base pairing combined with cationic/anionic backbone recognition between strands involving H-bond formation and salt bridging. Molecular-dynamics simulations corroborate interactions between the cationic backbones of the alpha-ONs and the anionic backbones of the nucleic acid targets. Moreover, ONs with guanidinium modification increased cellular uptake relative to negatively charged ONs. The cellular localization of these new cationic phosphoramidate ONs is mainly cytoplasmic. The uptake of these ON analogues might occur through endocytosis.     

Thickness-dependent optimization of Er3+ light emission from silicon-rich silicon oxide thin films

This study investigates the influence of the film thickness on the silicon-excess-mediated sensitization of Erbium ions in Si-rich silica. The Er3+ photoluminescence at 1.5 μm, normalized to the film thickness, was found five times larger for films 1 μm-thick than that from 50-nm-thick films intended for electrically driven devices. The origin of this difference is shared by changes in the local density of optical states and depth-dependent interferences, and by limited formation of Si-based sensitizers in "thin" films, probably because of the prevailing high stress. More Si excess has significantly increased the emission from "thin" films, up to ten times. This paves the way to the realization of highly efficient electrically excited devices.     

Oscillations make a self-scaled model for honeybees’ visual odometer reliable regardless of flight trajectory

Honeybees foraging and recruiting nest-mates by performing the waggle dance need to be able to gauge the flight distance to the food source regardless of the wind and terrain conditions. Previous authors have hypothesized that the foragers’ visual odometer mathematically integrates the angular velocity of the ground image sweeping backward across their ventral viewfield, known as translational optic flow. The question arises as to how mathematical integration of optic flow (usually expressed in radians/s) can reliably encode distances, regardless of the height and speed of flight. The vertical self-oscillatory movements observed in honeybees trigger expansions and contractions of the optic flow vector field, yielding an additional visual cue called optic flow divergence. We have developed a self-scaled model for the visual odometer in which the translational optic flow is scaled by the visually estimated current clearance from the ground. In simulation, this model, which we have called SOFIa, was found to be reliable in a large range of flight trajectories, terrains and wind conditions. It reduced the statistical dispersion of the estimated flight distances approximately 10-fold in comparison with the mathematically integrated raw optic flow model. The SOFIa model can be directly implemented in robotic applications based on minimalistic visual equipment.     

Investigation of fragments size resulting from dynamic fragmentation in melted state of laser shock-loaded tin

The understanding of dynamic fragmentation in shock-loaded metals and the evaluation of geometrical and kinematical properties of the resulting fragments are issues of considerable importance for both basic and applied science, for instance to predict the evolution of engineering structures submitted to high-velocity impact or explosive detonation. Among dynamic failure processes, spall fracture in solid materials has been extensively studied for many years, while scarce data can be found yet about how such phenomenon could evolve after partial or full melting on compression or on release. In this case, the dynamic fragmentation process, which may be referred to as ‘micro-spalling’, takes place in a liquid medium. It results in the formation of a cloud of fine molten droplets, ejected at high-velocity. The present work is devoted to experimental characterization, theoretical modelling and simulation of the ‘micro-spalling’ process in tin, with a specific emphasis on the size of the resulting fragments, namely the melted droplets. Laser-driven shock-loading experiments on tin have been performed. Post-test observations of the recovered fragments provide an insight into the actual fragmentation process and allow to infer the distribution of the fragments size which are found to be mostly sub-micrometric. Fragmentation modelling is based on a widely employed, energetic approach adapted to the case of liquids. This approach is implemented as a failure criterion in an one-dimensional hydrocode including a multiphase equation of state for tin. A fairly good agreement is obtained between experimental and computed sizes range. Some discrepancies are explained by both experimental uncertainties and model limitations which are carefully pointed out and discussed.     

Simulation and thermoeconomic analysis of different configurations of gas turbine (GT)-based dual-purpose power and desalination plants (DPPDP) and hybrid plants (HP)

This paper contains a simulation and a thermoeconomic analysis of several configurations of gas turbine (GT)-based dual-purpose power and desalination plants (DPPDP): Gas turbine with reverse osmosis (GT+RO), combined cycle with reverse osmosis (CC+RO), combined cycle with multi-effect distillation (CC+MED) and two different hybrid plant (HP) arrangements combining CC, MED and RO (CC+MED+RO, CC+MED+RO_bis). The last two configurations only differ from the feed solution to the MED units (raw seawater or brine coming from the RO discharge). A complete thermodynamic simulation at both design and at part load conditions has been made, as well as an exergy and an exergo-economic (thermoeconomic) analysis of each configuration, in order to compare the evolution of the water and electricity cost for different arrangements. The results show that even for a significantly reduced fuel cost (1.42 $/GJ), the CC is much more profitable than a GT operating in open cycle, with electricity cost values of 1.647 and 2.166 c$/kWh, respectively. As was expected, RO is more efficient and profitable than MED desalination processes, the difference in the obtained desalted water cost being significant. In the hybrid configuration with MED fed by the RO brine discharge, a decrease in the equivalent electrical consumption of nearly 2 kWh/m³ was achieved, but even in this case RO was more efficient (14.15 vs. 4.048 kWh/m³). The evolution of electricity cost in each configuration is more similar at part load operation than at full load, but in the case of water cost, RO is once again more profitable and less sensitive to load variations. Costs given in this paper correspond to investment and fuel costs. Further, profitability and operation strategies of HP, i.e., DPPDP combining distillation and membrane processes, are also analyzed. It is shown that HP can be more profitable than RO plants in the case of increasing the water production capacity of existing DPPDP, because the profit margin of HP remains positive within a substantial range for fuel price and investment costs. The operation strategies of HP were also studied in detail (by means of linear optimization) in order to minimize production costs; and it was concluded that electricity cost minimization gives the same result as the minimization of whole production cost; and water cost minimization could give a lower water cost than in the previous cases, but could lead to prohibitive electricity cost.     

DNA‐Directed Self‐Assembly of Core‐Satellite Plasmonic Nanostructures: A Highly Sensitive and Reproducible Near‐IR SERS Sensor

The excitation of surface plasmons in metallic nanostructures provides an opportunity to localize light at the nanoscale, well below the scale of the wavelength of the light. The high local electromagnetic field intensities generated in the vicinity of the nanostructures through this nanofocusing effect are exploited in surface enhanced Raman spectroscopy (SERS). At narrow interparticle gaps, so‐called hot‐spots, the nanofocusing effect is particularly pronounced. Hence, the engineering of substrates with a consistently high density of hot‐spots is a major challenge in the field of SERS. Here, a simple bottom‐up approach is described for the fabrication of highly SERS‐active gold core‐satellite nanostructures, using electrostatic and DNA‐directed self‐assembly. It is demonstrated that well‐defined core‐satellite gold nanostructures can be fabricated without the need for expensive direct‐write nanolithography tools such as electron‐beam lithography (EBL). Self‐assembly also provides excellent control over particle distances on the nanoscale. The as‐fabricated core‐satellite nanostructures exhibit SERS activities that are superior to commercial SERS substrates in signal intensity and reproducibility. This also highlights the potential of bottom‐up self‐assembly strategies for the fabrication of complex, well‐defined functional nanostructures with future applications well beyond the field of sensing.     

A Gd-Film Thermomagnetic Generator in Resonant Self-Actuation Mode

Thermomagnetic generation is a promising technology for conversion of low-grade waste heat into electricity. Key requirements for the development of efficient thermomagnetic generators (TMGs) are tailored thermomagnetic materials as well as innovative designs enabling fast heat transfer. Recently, film-based thermomagnetic generators are developed that operate in the mode of resonant self-actuation enabling high frequency and stroke of a movable cantilever and, thus, efficient conversion of thermal energy into electrical energy. Here, the performance of a Gadolinium (Gd)-film-based TMG that is optimized for resonant self-actuation near room temperature is reported. The Gd-film TMG exhibits large oscillation frequencies up to 106 Hz and large strokes up to 2 mm corresponding to 38% of the oscillating cantilever's length. This performance occurs in a sharply bound range of ambient temperatures with an upper limit near the film's ferromagnetic to paramagnetic transition temperature T_c of 20 °C and of heat source temperatures ranging between 40 and 75 °C. The maximum power per footprint is 23.8 µWcm⁻², at which the Gd film undergoes a temperature change of only 0.9 °C at ≈10 °C above T_c.