For small meteoric bodies, terminating high in the atmosphere (i.e.
under free molecular conditions) it was possible to neglect the effect of thermal motions of air particles. As regards fireballs, bodies with masses in excess of about 0.1 kg, penetrating deep into the atnosphere, the ambient atmosphere has the properties of a continuous medium. Under these conditions, the thermal motions of atmospheric particles behind ťhe shock wave become
the decisive factor for momentum and energy transfer to the meteoroid. F'or fireballs these thermal motions practically replace the effect of direct impacts of particles of hie undisturbed atmosphere, considered earlier under free molecular conditions. The form of the equations, describing the motion and ablation of a large body (fireball) will remain the same as for small bodies, but the coefficients occurring in the equations will have a different
physical meaning.
In a previous paper (Padevet, 1984), the author pointed out the decisive role of thermal motions of air particles in the continuous medium behind a shock wave for fireballs. Nevertheless, the change in quality of the mechanism of momentum and energy transfer had practically no effect on the values of the transferred quantities. It was found that the role of thernal motions of particles of meteoric material becomes distinctly manifest only if the interaction of the atmosphee with the ablated meteoric material is considered. This may explain some of the observed phenomena, e.g. the "mass paradox", or the photographed fragmentation of fireballs. It also appears probable that all four groups of fireballs, I, II, IIIA, IIIB, determined earlier, can be assigned to known types of meteorites, in particular to chondrites of four known types, viz H, L, CM and CI. However, the theory of fireballs in a continuous medium should be further developed in several directions, as pointed out by the author in the discussion.
The tissue factor (TF) is one of the most important regulators of arterial thrombosis. Because arterial thrombosis is the pathophysiologic background of acute coronary syndrome, the possible impact of blocking the arterial thrombosis on its onset is a challenging problem. The investigations of TF brought a new concept of “cell-based coagulation model” which highlighted the question of blood-borne TF as a source of TF in circulating blood. In this review we summarize essential information on the pathophysiology, molecular structure, expression and distribution of TF and we propose a novel concept of blood-borne TF, suggesting the possibilities of inhibition of the coagulation cascade with newly synthetized drugs., M. A. Malý, P. Tomašov, P. Hájek, P. Blaško, I. Hrachovinová, P. Salaj, J. Veselka., and Obsahuje bibliografii a bibliografické odkazy
The aim of this study was to explore changes in plasma vascular endothelial growth factor (VEGF) in aged patients who undergone transcatheter aortic valve implantation or balloon angioplasty for the treatment of aortic stenosis. Plasma VEGF was measured in subjects with diabetes mellitus type 2 (DM) (n=21, age 79.2±1.6 years) and in non-diabetic subjects (non-DM) (n=23, age 84.4±0.7 years), using an ELISA kit. Before the procedure plasma levels of VEGF were significantly lower in DM than in non-DM patients (P<0.05). Plasma VEGF significantly increased in both groups (DM and non-DM) 24 h (387±64 vs. 440±30 pg/ml, P<0.05) and 72 h (323±69 vs. 489±47 pg/ml, P<0.05) after the endovascular procedure. However, the VEGF in DM patients was significantly lower compared to non-DM subjects up to one month after the endovascular procedure (283±47 vs. 386±38 pg/ml, P<0.05). We conclude that increased plasma VEGF in aged patients associates with atherosclerotic aortic valve stenosis. In spite of that plasma VEGF in DM was constantly significantly lower than in non diabetic patients, both before and after the endovascular procedure, possibly reflecting a disturbance of angiogenic/antiangiogenic balance in diabetes., V. Bláha, J. Šťásek, J. Bis, J. Fortunato, C. Andrýs, V. Pavlík, P. Polanský, M. Brtko, L. Sobotka., and Obsahuje bibliografii
It is shown that coherent electrodynamics of water molecules produces extended regions where the chemical activity of bio-molecules is governed in a selective way by a code based on frequency resonance. Coherence Domains of water act as devices able to collect low-grade energy in the environment and to transform it into high-grade energy able to produce electronic excitations.
Water is the most important constituent of all living organisms (70% of the total mass and 99% of all molecules). Other biomolecules, proteins, fats, sugars, vitamins, salts, which are usually considered the only molecules playing a remarkable role in molecular biology, make up only 1% of the total. So, biological activity is assumed to involve 1% of all molecules only.
What is the role of water then? Is it possible that 99% of all biomolecules are necessary only as a solvent whereas the ``really essential'' biomolecules enact all productive activity?
The driving and regulatory role of water in governing the biochemical activity has begun to be recognized in recent times (Voeikov, 2007).
In order to unravel this puzzle, we should take another enigma, which is the existence of biochemical codes (Barbieri, 2004), into account. Apart from the living matter or more generally far from catalysts, molecules are usually subjected to a polygamous regime; each biomolecule can interact with many others, thus producing a great number of reactions. In living matter, instead, biomolecules live inside each particular biochemical cycle in a monogamous condition (at least within definite time intervals), i.e. a biomolecule interacts only with well-defined partners and ignores the other biomolecules, with which interaction would be possible in empty space. Living matter therefore produces a ``context'' capable of preventing a great number of chemical interactions, which would theoretically be possible. The possibility of molecular interactions is governed by biochemical codes (the genetic code is the most widely known among them), to which particular biological processes correspond. Within the world of biomolecules, there are thus the prerequisites for communication. Indeed, biochemical cycles are open and capable of reacting against new influences. In this way all the codes build up and adopt flexible features, which are typical of a language.
The emergence of these biochemical codes from the dynamics of matter is undoubtedly the main problem of biology.
Naturally occurring veinless specimen of the swallowtail Papilio xuthus show an extremely aberrant colour pattern. In spite of the fact that we have no breeding data, these veinless specimen are provisionally called veins-reduced mutant. In these mutants seven longitudinal veins of the fore wing and five of the hind wing are absent. The absence of wing veins is associated with a loss of the broad black venous stripes that normally are present along the proximal portion of the veins. In addition, missing veins cause a loss of the dislocation of black bands in adjacent wing cells, so that what are discrete black segments in normal wings become continuous bands in the veinless wing. Computer simulations show that the morphology of the striped patterns on both the veinless and veined wing can be explained if the wing margin acts as an inductive source of pattern formation and the veins act simply as boundaries to the propagation of the signal from the wing margin. The vein-dependent patterns by contrast, require that the veins act as inductive sources, at least along their proximal portion. This dual role of wing veins is consistent with prior observations on the biology of colour pattern formation. The unique veinless colour pattern strongly supports the hypothesis that the wing margin is the dominant organiser of colour pattern in this species, and possibly in other Papilionidae.
The cocoons characteristic of the prepupal and pupal stages of many insects vary widely in size, durability, structure, shape and colour, as well as in other features such as orientation and attachment to the substrate. In some species they vary seasonally. Most cocoons provide little direct insulation, although they may reduce the rate at which temperature changes, but many provide the mechanical protection required for overwintering beneath insulating substrates such as soil and snow. The cocoons of some terrestrial species prevent inoculative freezing by isolating the integument from ice crystals on the cocoon surface or its surroundings. In some aquatic species, cocoons appear to limit damage by providing mechanical protection during the freezing of surrounding water. Some cocoons help in the acquisition of solar heat: dark structures are especially effective because dark pigments absorb heat, and surrounding layers trap this heat. Insects are immobilized when it is cold and so cannot move in response to environmental threats, and protective cocoons made for winter tend to be more robust than their summer counterparts. Such cocoons protect against abrasion of the waterproof layer of the cuticle. In some species, robust cocoons or complex structures impede natural enemies. Cocoon silk has anti-bacterial and anti-fungal actions. Other cocoons are more or less waterproof. These and other features withstand simultaneous constraints in addition to cold. Therefore, cocoons enhance survival during cold conditions in many species. However, this conclusion is based on fragmentary evidence, and there has been relatively little explicit examination of the roles of cocoons during winter. Therefore, specific work is required to assess resistance to or enhancement of inoculative freezing, resistance to penetration by natural enemies and water, the roles of particular cocoon silks and silk constituents, and the quantitative contributions of cocoons to winter survival in nature.
We present the Rothe method for the McKendrick-von Foerster equation with initial and boundary conditions. This method is well known as an abstract Euler scheme in extensive literature, e.g. K. Rektorys, The Method of Discretization in Time and Partial Differential Equations, Reidel, Dordrecht, 1982. Various Banach spaces are exploited, the most popular being the space of bounded and continuous functions. We prove the boundedness of approximate solutions and stability of the Rothe method in $L^\infty $ and $L^1$ norms. Proofs of these results are based on comparison inequalities. Our theory is illustrated by numerical experiments. Our research is motivated by certain models of mathematical biology.