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Search Results: 1 - 10 of 29487 matches for " Martin Horná?ek "
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Prediction of External Exposure during Dismantling of Steam Generator  [PDF]
Martin Horná?ek, Vladimír Ne?as
World Journal of Engineering and Technology (WJET) , 2015, DOI: 10.4236/wjet.2015.33C023

The decommissioning of nuclear power plants is in the Slovak Republic an actual issue. In 2015 started the second decommissioning stage of nuclear power plant V1 in Jaslovské Bohunice. This stage involves the dismantling and segmentation of activated (reactor pressure vessel, reactor internals) and contaminated parts (steam generators, pressurizer). From this reason it is necessary to investigate the radiation situation in the vicinity of the component to be cut. The presented results show that during remote dismantling the exposure is small (compared with the fragmentation tasks). Moreover, when the pre-dismantling decontamination with decontamination factor of 100 is applied, the total collective effective dose is below the yearly limit of 20 mSv for workers.

Profiling of proteolytic enzymes in the gut of the tick Ixodes ricinus reveals an evolutionarily conserved network of aspartic and cysteine peptidases
Daniel Sojka, Zdeněk Franta, Martin Horn, Ond?ej Hajdu?ek, Conor R Caffrey, Michael Mare?, Petr Kopá?ek
Parasites & Vectors , 2008, DOI: 10.1186/1756-3305-1-7
Abstract: Using the hard tick, Ixodes ricinus, we performed a functional activity scan of the peptidase complement in gut tissue extracts that demonstrated the presence of five types of peptidases of the cysteine and aspartic classes. We followed up with genetic screens of gut-derived cDNA to identify and clone genes encoding the cysteine peptidases cathepsins B, L and C, an asparaginyl endopeptidase (legumain), and the aspartic peptidase, cathepsin D. By RT-PCR, expression of asparaginyl endopeptidase and cathepsins B and D was restricted to gut tissue and to those developmental stages feeding on blood.Overall, our results demonstrate the presence of a network of cysteine and aspartic peptidases that conceivably operates to digest host blood proteins in a concerted manner. Significantly, the peptidase components of this digestive network are orthologous to those described in other parasites, including nematodes and flatworms. Accordingly, the present data and those available for other tick species support the notion of an evolutionary conservation of a cysteine/aspartic peptidase system for digestion that includes ticks, but differs from that of insects relying on serine peptidases.Ticks are important vectors of infectious agents causing diseases in human and domestic animals [1]. The castor bean tick Ixodes ricinus transmits Lyme disease caused by Borrelia burgdorferi spirochetes and tick borne encephalitis caused by the tick-borne encephalitis virus [2].Blood-feeding and -digestion are essential activities for ticks. Blood provides a rich source of proteins and nutrients for anabolic processes such as vitellogenesis and egg production [3]. Unlike other blood-feeding arthropods, ticks are believed to digest blood intracellularly – in the endo/lysosomal vesicles of gut cells [4] at pH values well below the pH 6.3 – 6.5 of the gut contents [5,6]. Digestive gut cells use both receptor-mediated and fluid-phase endocytoses to uptake the liquid blood meal from the gut lumen [7].
Dynamics of digestive proteolytic system during blood feeding of the hard tick Ixodes ricinus
Zdeněk Franta, Helena Frantová, Jitka Konvi?ková, Martin Horn, Daniel Sojka, Michael Mare?, Petr Kopá?ek
Parasites & Vectors , 2010, DOI: 10.1186/1756-3305-3-119
Abstract: This study reveals the digestive machinery of the I. ricinus during the course of blood-feeding on the host. The dynamic profiling of concentrations, activities and mRNA expressions of the major digestive enzymes demonstrates that the de novo synthesis of peptidases triggers the dramatic increase of the hemoglobinolytic activity along the feeding period. Overall hemoglobinolysis, as well as the activity of digestive peptidases are negligible at the early stage of feeding, but increase dramatically towards the end of the slow feeding period, reaching maxima in fully fed ticks. This finding contradicts the established opinion that blood digestion is reduced at the end of engorgement. Furthermore, we show that the digestive proteolysis is localized intracellularly throughout the whole duration of feeding.Results suggest that the egressing proteolytic system in the early stage of feeding and digestion is a potential target for efficient impairment, most likely by blocking its components via antibodies present in the host blood. Therefore, digestive enzymes are promising candidates for development of novel 'anti-tick' vaccines capable of tick control and even transmission of tick-borne pathogens.Ticks are blood-sucking ectoparasites that may do harm to their host by severe blood loss, but the main danger of ticks remain their capability to transmit a wide variety of pathogens comprising viruses, bacteria and protozoa [1], causing diseases in humans and animals [2]. The miscellaneous vectorial capacity of ixodid ticks is due to their long-term co-evolution with the pathogens that they transmit, extended lifespan (up to years), the long-lasting blood feeding of all parasitic stages on different hosts and other aspects of tick biology [3]. Moreover, the transmission of pathogens is facilitated by the modulation of host haemostatic, inflammatory and immune responses, mediated by the inexhaustible pharmacology of the molecules present in tick saliva [4]. The castor bean tick,
Quaternions in University-Level Physics Considering Special Relativity
Martin Erik Horn
Physics , 2003,
Abstract: As an expansion of complex numbers, the quaternions show close relations to numerous physically fundamental concepts. In spite of that, the didactic potential provided by quaternion interrelationships in formulating physical laws are hardly regarded in the current physics curriculum. In particular, many approaches emerge that are useful in conveying the unity of seemingly distinct theories in a didactically convincing manner. This will be exemplified with the help of special relativity. The diverse examples of spatial and space-time rotations are merged into a didactic whole by introducing quaternion transformations and comparing them to the representation using rotation matrices common in physics books.
The Didactical Relevance of the Pauli Pascal Triangle (Die didaktische Relevanz des Pauli-Pascal-Dreiecks)
Martin Erik Horn
Physics , 2006,
Abstract: In high school physics and physics at university level anti-commutative and non-commutative quantities play an outstanding role at the theoretical description of physical relations. But while using commutative quantities, the basic formal relations of mathematical physics are introduced clearly and step-by-step, a similar clear presentation of non-commuatative relations with didactical sensible examples is lacking. On the basis of a q-analog of the Pascal triangle (sometimes called quantum Pascal triangle) this paper discusses whether a less abstract introduction into non-commutative relations is possible. The didactical relevance of this approach is analysed. In an attachment all three triangles of the Pauli Pascal plane are presented.
Quaternionen and Geometric Algebra (Quaternionen und Geometrische Algebra)
Martin Erik Horn
Physics , 2007,
Abstract: In the last one and a half centuries, the analysis of quaternions has not only led to further developments in mathematics but has also been and remains an important catalyst for the further development of theories in physics. At the same time, Hestenes geometric algebra provides a didactically promising instrument to model phenomena in physics mathematically and in a tangible manner. Quaternions particularly have a catchy interpretation in the context of geometric algebra which can be used didactically. The relation between quaternions and geometric algebra is presented with a view to analysing its didactical possibilities.
Energy flow lines as light paths: a didactical analysis (Energiestromlinien als Lichtwege: Eine didaktische Analyse)
Martin Erik Horn
Physics , 2006,
Abstract: Analyses of interviews with secondary school students about their conceptions of light at the University of Potsdam indicate that numerous students have a deterministic view of light. With regard to these results the model of energy flow lines, which has been discussed recently in the didactical literature, is of special interest. Following this model, light is presumed to move along energy flow lines as trajectories. In an analysis of the model of energy flow lines four didactical dimensions (didactical content, internal structure, present-day relevance and future significance) are investigated. It can be shown that a discussion of this model in physics at school can increase the meta-conceptional knowledge of the students about the models of light. On the other hand, this can promote deterministic conceptions and the Bohm interpretation of quantum mechanics. But the question remains: Should the nature of light really be described as deterministic?
Pascal Pyramids, Pascal Hyper-Pyramids and a Bilateral Multinomial Theorem
Martin Erik Horn
Mathematics , 2003,
Abstract: Part I: The two-dimensional Pascal Triangle will be generalized into a three-dimensional Pascal Pyramid and four-, five- or whatsoever-dimensional hyper-pyramids. Part II: The Bilateral Binomial Theorem will be generalised into a Bilateral Trinomial Theorem resp. a Bilateral Multinomial Theorem.
The Bilateral Vandermonde Convolution
Martin Erik Horn
Mathematics , 2003,
Abstract: A new and easy way of deriving Gauss's Generalized Hypergeometric Theorem is presented by using the Bilateral Binomial Theorem.
Bilateral binomial duplication formula
Martin Erik Horn
Mathematics , 2006,
Abstract: The bilateral binomial theorem with step width two gives a bilateral hypergeometric formula for 2H2(a, a+1/2; c, c+1/2; z).
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