Aurore: A platform for ultrafast sciences.

We present the Aurore platform for ultrafast sciences. This platform is based on a unique 20 W, 1 kHz, 26 fs Ti:sapphire laser system designed for reliable operation and high intensity temporal contrast. The specific design ensures the high stability in terms of pulse duration, energy, and beam pointing necessary for extended experimental campaigns. The laser supplies 5 different beamlines, all dedicated to a specific field: attosecond science (Aurore 1), ultrafast phase transitions in solids (Aurore 2 and 3), ultrafast luminescence in solids (Aurore 4), and femtochemistry (Aurore 5). The technical specifications of these five beamlines are described in detail, and examples of the recent results are given.

Effect of Platinum Nanoparticles on the Structure of Protein Molecules and Regulation of the Tone of Brain Vessels in Experimental Animals.

The effects of platinum nanoparticles on the morphological structures of the solid phase of blood serum and the tone of cerebral microvessels as indicators of the dynamics of homeostasis were studied on outbred albino male rats (n=40) weighing 300-350 g. Platinum nanoparticles were injected to experimental animals in 1 ml of physiological saline. For systemic BP measurements and blood sampling, the femoral artery was isolated and catheterized. The study of solid phase structures of blood serum was conducted by the method of cuneiform dehydration. The results showed that injection of platinum nanoparticles significantly affected the body of experimental animals.

Interaction between particles with inhomogeneous surface charge distributions: Revisiting the Coulomb fission of dication molecular clusters.

An analytical solution describing the electrostatic interaction between particles with inhomogeneous surface charge distributions has been developed. For particles, each carrying a single charge, the solution equates to the presence of a point charge residing on the surface, which makes it particularly suitable for investigating the Coulomb fission of doubly charged clusters close to the Rayleigh instability limit. For a series of six separate molecular dication clusters, center-of-mass kinetic energy releases have been extracted from experimental measurements of their kinetic energy spectra following Coulomb fission. These data have been compared with Coulomb energy barriers calculated from the electrostatic interaction energies given by this new solution. For systems with high dielectric permittivity, results from the point charge model provide a viable alternative to kinetic energy releases calculated on the assumption of a uniform distribution of surface charge. The equivalent physical picture for the clusters would be that of a trapped proton. For interacting particles with low dielectric permittivity, a uniform distribution of charge provides better agreement with the experimental results.

"Cylindrical worlds" in biology: Does the aggregation strategy give a selective advantage?

Tree trunks and other cylindrical objects, where aggregated insects live, represent a very specific world for predator-prey interactions, which must differ from the situation on a 2D plane. In the present paper, in order to gain a better understanding of the specificity of predator-prey interaction in a cylindrical space, we applied a theoretical approach. Here we introduce a numerical model that allows us to test the effect of different interaction properties between predator and aggregated prey on the plane (2D) and on a cylinder (3D), taking into consideration different abilities of predators to visually detect the prey in these two types of space. The main aim was to test these interactions in an environment, which more realistically reproduces the conditions where aggregated insects usually live. We showed that the aggregation in conjunction with a specific environment may bring additional advantages for the prey. When one prey subgroup aggregates on the other side of the tree trunk and becomes invisible behind the horizon of events for the predator, the subgroup will survive with an extremely high probability. After all, the predator moving along one side of the tree will finally loose the major group completely.

Numerical simulation of the pattern formation of the springtail cuticle nanostructures.

Springtails (Collembola) are known to exhibit complex hierarchical nanostructures of their exoskeleton surface that repels water and other fluids with remarkable efficiency. These nanostructures were previously widely studied due to their structure, chemistry and fluid-repelling properties. These ultrastructural and chemical studies revealed the involvement of different components in different parts of the nanopattern, but the overall process of self-assembly into the complex rather regular structures observed remains unclear. Here, we model this process from a theoretical point of view partially using solutions related to the so-called Tammes problem. By using densities of three different reacting substances, we obtained a typical morphology that is highly similar to the ones observed on the cuticle of some springtail species. These results are important not only for our understanding of the formation of hierarchical nanoscale structures in nature, but also for the fabrication of novel surface coatings.

Effects of molecule anchoring and dispersion on nanoscopic friction under electrochemical control.

The application of electric fields is a promising strategy for in situ control of friction. While there have recently been many experimental studies on friction under the influence of electric fields, theoretical understanding is very limited. Recently, we introduced a simple theoretical model for friction under electrochemical conditions that focused on the interaction of a force microscope tip with adsorbed molecules whose orientation was dependent on the applied electric field. Here we focus on the effects of anchoring of the molecules on friction. We show that anchoring affects the intensity and width of the peak in the friction that occurs near a reorientation transition of adsorbed molecules, and explain this by comparing the strength of molecule-molecule and molecule-tip interactions. We derive a dispersion relation for phonons in the layer of adsorbed molecules and demonstrate that it can be used to understand important features of the frictional response.

[Characterization of the intestinal digestive glycosidases in plankton- and benthos-feeding species of the fish genus Ballerus (Cyprinidae)].

The activity of hydrolases (maltase, saccharase, amylolytic activity) in the intestinal mucosa of the plankton-feeding zope Ballerus ballerus and the benthos-feeding white-eye bream Ballerus sapa was investigated. The temperature characteristics of maltase hydrolysis (T(opt) and E(act)) are similar in both species. The lower K(m) of maltase hydrolysis in the white-eye bream reflects a higher enzyme/substrate affinity and indicates a more effective carbohydrate hydrolysis in the benthos-versus plankton-feeding species. The glycosidase activity in the white-eye bream is twice as high as in the zope. This may be due not only to different feeding spectra and biochemical food contents but also to the differences in thyroid status of species under consideration.

High-resolution NMR structure of the antimicrobial peptide protegrin-2 in the presence of DPC micelles.

PG-1 adopts a dimeric structure in dodecylphosphocholine (DPC) micelles, and a channel is formed by the association of several dimers but the molecular mechanisms of the membrane damage by non-α-helical peptides are still unknown. The formation of the PG-1 dimer is important for pore formation in the lipid bilayer, since the dimer can be regarded as the primary unit for assembly into the ordered aggregates. It was supposed that only 12 residues (RGGRL-CYCRR-RFCVC-V) are needed to endow protegrin molecules with strong antibacterial activity and that at least four additional residues are needed to add potent antifungal properties. Thus, the 16-residue protegrin (PG-2) represents the minimal structure needed for broad-spectrum antimicrobial activity encompassing bacteria and fungi. As the peptide conformation and peptide-to-membrane binding properties are very sensitive to single amino acid substitutions, the solution structure of PG-2 in solution and in a membrane mimicking environment are crucial. In order to find evidence if the oligomerization state of PG-1 in a lipid environment will be the same or not for another protegrins, we investigate in the present work the PG-2 NMR solution structure in the presence of perdeuterated DPC micelles. The NMR study reported in the present work indicates that PG-2 form a well-defined structure (PDB: 2MUH) composed of a two-stranded antiparallel ß-sheet when it binds to DPC micelles.

[Thiotriazoline in the Treatment of Stable Angina Pectoris of II-III Functional Class].

Trimetazidine is a metabolic agent of proven efficacy in improving myocardial ischemia and angina. A comparative international multicenter randomized trial, assessed anti-anginal anti ischemic efficacy and safety of Trimetazidine (60 mg/d) and Thiotriazoline (600 mg/d) in symptomatic patients with chronic ischemic heart disease receiving the first line therapy. The study assessed the efficacy of the two drugs on total exercise duration, time to 1-mm ST segment depression, the number of angina attacks and nitroglycerin tablets consumed amount. Both drugs have demonstrated clinical efficacy equal for all primary and secondary endpoints.

[Thiotriazoline in the Treatment of Stable Angina IIIII Functional Class].

Trimetazidine is a metabolic agent of proven efficacy in improving myocardial ischemia and angina. A comparative international multicenter randomized trial, assessed anti-anginal anti ischemic efficacy and safety of Trimetazidine (60 mg/d) and Thiotriazoline (600 mg/d) in symptomatic patients with chronic ischemic heart disease receiving the first line therapy. The study assessed the efficacy of the two drugs on total exercise duration, time to 1-mm ST segment depression, the number of angina attacks and nitroglycerin tablets consumed amount. Both drugs have demonstrated clinical efficacy equal for all primary and secondary endpoints.

Nanoscopic friction under electrochemical control.

We propose a theoretical model of friction under electrochemical conditions focusing on the interaction of a force microscope tip with adsorbed polar molecules whose orientation depends on the applied electric field. We demonstrate that the dependence of friction force on the electric field is determined by the interplay of two channels of energy dissipation: (i) the rotation of dipoles and (ii) slips of the tip over potential barriers. We suggest a promising strategy to achieve a strong dependence of nanoscopic friction on the external field based on the competition between long-range electrostatic interactions and short-range chemical interactions between tip and adsorbed polar molecules.

[Structure of amyloid-beta peptides in a complex with model membranes].

Structures of amyloid-beta peptides Aß1-40, Aß10-35, Aß13-23 and Aß16-22 in a complex with model membranes in solution were obtained on the analysis of NMR experimental data. It has been established that the process of peptide-micelle complex formation occurs through the amino acid residues L17, F19, F20 and G29-M35.

[Objectivization of the choice of the amputation level in patients with lower limb critical ischaemia].

The authors compared the informative value of the intraoperative criteria for assessing viability of muscles in high amputations of limbs for chronic critical ischaemia. It was revealed that such signs as subjectively evaluated bleeding, contractility and oedema of muscles possess low specificity in relation to the development of early postoperative complications. Intraoperative macroscopic histochemical study (IHCS) of the activity of muscular tissue lactate dehydrogenase at the level of amputation showed sensitivity of 96,3% and specificity of 92,9 %. Taking into consideration the results of IHCS for objectivization of the choice of the level of amputation made it possible to save the knee joint in 8,9 % of patients with gangrene on the background of high occlusion of lower limb arteries and to decrease the frequency of postoperative necrosis of muscle of the stump from 15,0% to 3,5%.

Friction between a viscoelastic body and a rigid surface with random self-affine roughness.

In this Letter, we study the friction between a one-dimensional elastomer and a one-dimensional rigid body having a randomly rough surface. The elastomer is modeled as a simple Kelvin body and the surface as self-affine fractal having a Hurst exponent H in the range from 0 to 1. The resulting frictional force as a function of velocity always shows a typical structure: it first increases linearly, achieves a plateau and finally drops to another constant level. The coefficient of friction on the plateau depends only weakly on the normal force. At lower velocities, the coefficient of friction depends on two dimensionless combinations of normal force, sliding velocity, shear modulus, viscosity, rms roughness, rms surface gradient, the linear size of the system, and the Hurst exponent. We discuss the physical nature of different regions of the law of friction and suggest an analytical relation describing the coefficient of friction in a wide range of loading conditions. An important implication of the analytical result is the extension of the well-known "master curve procedure" to the dependencies on the normal force and the size of the system.

[Bubbles induced fluctuations of some properties of aqueous solutions].

A mathematical model of the air diffusion process through the water surface, taking into account the reverse flow of bubbles was proposed. The numerical solving gives self-oscillation of the dissolved air concentration. Spectral density of these oscillations has the 1/f-noise form, which explains the fluctuating nature of the observed properties of water and biological effects, which depend on the amount of dissolved air. A mechanism of spontaneous water luminescence observed after laser irradiation was suggested. The calculated luminescence self-oscillations have the form of a fractal with an infinite sequence of periods, which evolve in time and that is qualitatively consistent with the experiment.

[The influence of ezetimibe and simvaststin on platelet aggregation and protein c system in patients with coronary heart disease and hypercholesterolemia].

Therapy with ezetimib (10 mg daily for 2 weeks) caused a 24% reduction of plasma LDL cholesterol level (p < 0.05) and maximum ADP and collagen-induced platelet aggregation from 76.2 +/- 1.54 to 65.3 +/- 3.38% and from 71.5 +/- 3.98 to 53.6 +/- 5.24% (p < 0.05) respectively. Combination of ezetimibe and simvaststin did not produce an additional decrease in platelet aggregation.

[Intra-operative histochemical detection of vitalized muscular tissue during lower limb amputation for chronic critical ischemia].

Direct results of 747 lower limb amputations for chronic critical lower limb ischemia were analyzed. Early postoperative complications were observed in 45,1% of cases. Among them 45,4% were caused by tissue ischemia. Basing on detection of lactate dehydrogenase activity in muscular tissue method of intra-operative evaluation of tissue ischemia at the level of amputation is proposed. Relationship between this index and frequency of early postoperative complications is proved.

[Immobilization of the glutathione by the complementary coordination binding].

A simple method for immobilization of biologically imporant molecules with many functional fragments by selective binding of their thiogroups with the surface caroxyl groups by cadmium ions was proposed. Biofunctional properties of these structures were studied by surface plasmon resonance method on the model of the glutathione (GSH), which was immobilized by means of mixed (a:b form 1:100 o 1:700) thiol monolayers with terminal groups of the methyl/hydroxyl (b) and carboxyl (a) type. The maintenance of the biofunctional conformation ofglutathione-S-transferase (GST) after its interaction with GSH was checked by the use of specific anti-GST antibodies. It was shown that CH3 matrix has considerable non-specific binding and is not suitable for the formation of the biofunctional GST layer. At the same time OH-based structures demonstrate specific interaction GST-anti-GST, the stoichiometry of which corresponds to the bidentate binding. Considered simple method of the immobilization can be used to create the functional surface architectures in the analyticasl biochemistry and chemical analysis.

Lateral diffusion in sphingomyelin bilayers.

Sphingomyelin (SM) is an important lipid of eukaryotic cellular membranes and neuronal tissues. We studied lateral diffusion in macroscopically oriented bilayers of synthetic palmitoylsphingomyelin (PSM) and natural sphingomyelins of egg yolk (eSM), bovine brain (bSM) and bovine milk (mSM) by pulsed field gradient NMR (PFG NMR) in the temperature range 45-60 °C. We found that the mean values of lateral diffusion coefficients (LDCs) of SMs are 1.9-fold lower compared with those of dipalmitoylphosphatidylcholine (DPPC), which is similar in molecular structure. This discrepancy could be explained by the characteristics of intermolecular SM interactions. The LDCs of different SMs differ: egg SM is most similar to PSM; both of them have a 10% higher LDC value compared with the other two natural SMs. Besides, all natural SMs show a complicated form of the spin-echo diffusion decay (DD), which is an indicator of a distribution of LDC values in bilayers. This peculiarity is explained by the broad distributions of hydrocarbon chain lengths of the natural SMs studied here, especially mSM and bSM. We confirmed the relationship between chain length and LDC in the bilayers by computer analysis of a set of (1)H NMR spectra obtained by scanning the value of the pulsed field gradient. There is a correlation between lower LDC values and SM molecules with longer acyl chains. The most probable mechanisms by which long-chain SM molecules decrease their lateral diffusion relative to the average value are protrusion into the other side of the bilayer or lateral separation into areas that diverge with their LDCs.