ABSTRACT
Linearity of response belongs to fundamental characteristics of neutron detection systems. Research reactors are valuable tools for neutron detector non-linearity studies as they offer a wide range of neutron fluxes. For neutron detection systems working in pulse mode they enable to characterise detector response non-linearity from some hundreds of cps up to the maximum reachable count rates. The paper presents comparison of two methods for neutron pulse-mode detector non-linearity characterisation using VR-1 zero power reactor: (1) comparative method utilising the comparison of studied pulse-mode detection system with a response of gamma compensated ionisation chamber working in current mode, and (2) kinetics method utilising the asymptotic exponential power rise after positive reactivity insertion as a source of information on true signal. Further several approaches for dead time determination based on theoretical formulae describing paralysable and non-paralysable dead time behaviour of detectors were studied and their usability to characterise the count-rate dependent detector response was analysed.
Subject(s)
Algorithms , Neutrons , Radiometry/instrumentation , Gamma Rays , Humans , Monte Carlo MethodABSTRACT
Cellular motility is essential for microscopic parasites, it is used to reach the host, migrate through tissues, or evade host immune reactions. Many cells employ an evolutionary conserved motor protein- actin, to crawl or glide along a substrate. We describe the peculiar movement of Sphaerospora molnari, a myxozoan parasite with proliferating blood stages in its host, common carp. Myxozoa are highly adapted parasitic cnidarians alternately infecting vertebrates and invertebrates. S. molnari blood stages (SMBS) have developed a unique "dancing" behaviour, using the external membrane as a motility effector to rotate and move the cell. SMBS movement is exceptionally fast compared to other myxozoans, non-directional and constant. The movement is based on two cytoplasmic actins that are highly divergent from those of other metazoans. We produced a specific polyclonal actin antibody for the staining and immunolabelling of S. molnari's microfilaments since we found that neither commercial antibodies nor phalloidin recognised the protein or microfilaments. We show the in situ localization of this actin in the parasite and discuss the importance of this motility for evasion from the cellular host immune response in vitro. This new type of motility holds key insights into the evolution of cellular motility and associated proteins.
Subject(s)
Actins/immunology , Antibodies/metabolism , Carps/blood , Myxozoa/physiology , Animals , Carps/parasitology , Cell Movement , Cloning, Molecular , Cytoplasm/metabolism , Phylogeny , Protozoan Proteins/immunologyABSTRACT
The challenge of modelling cancer presents a major opportunity to improve our ability to reduce mortality from malignant neoplasms, improve treatments and meet the demands associated with the individualization of care needs. This is the central motivation behind the ContraCancrum project. By developing integrated multi-scale cancer models, ContraCancrum is expected to contribute to the advancement of in silico oncology through the optimization of cancer treatment in the patient-individualized context by simulating the response to various therapeutic regimens. The aim of the present paper is to describe a novel paradigm for designing clinically driven multi-scale cancer modelling by bringing together basic science and information technology modules. In addition, the integration of the multi-scale tumour modelling components has led to novel concepts of personalized clinical decision support in the context of predictive oncology, as is also discussed in the paper. Since clinical adaptation is an inelastic prerequisite, a long-term clinical adaptation procedure of the models has been initiated for two tumour types, namely non-small cell lung cancer and glioblastoma multiforme; its current status is briefly summarized.
