119 research outputs found

    Atmospheric Muon Flux at Sea Level, Underground, and Underwater

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    The vertical sea-level muon spectrum at energies above 1 GeV and the underground/underwater muon intensities at depths up to 18 km w.e. are calculated. The results are particularly collated with a great body of the ground-level, underground, and underwater muon data. In the hadron-cascade calculations, the growth with energy of inelastic cross sections and pion, kaon, and nucleon generation in pion-nucleus collisions are taken into account. For evaluating the prompt muon contribution to the muon flux, we apply two phenomenological approaches to the charm production problem: the recombination quark-parton model and the quark-gluon string model. To solve the muon transport equation at large depths of homogeneous medium, a semi-analytical method is used. The simple fitting formulas describing our numerical results are given. Our analysis shows that, at depths up to 6-7 km w. e., essentially all underground data on the muon intensity correlate with each other and with predicted depth-intensity relation for conventional muons to within 10%. However, the high-energy sea-level data as well as the data at large depths are contradictory and cannot be quantitatively decribed by a single nuclear-cascade model.Comment: 47 pages, REVTeX, 15 EPS figures included; recent experimental data and references added, typos correcte

    Genome-Scale Modeling of Light-Driven Reductant Partitioning and Carbon Fluxes in Diazotrophic Unicellular Cyanobacterium Cyanothece sp. ATCC 51142

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    Genome-scale metabolic models have proven useful for answering fundamental questions about metabolic capabilities of a variety of microorganisms, as well as informing their metabolic engineering. However, only a few models are available for oxygenic photosynthetic microorganisms, particularly in cyanobacteria in which photosynthetic and respiratory electron transport chains (ETC) share components. We addressed the complexity of cyanobacterial ETC by developing a genome-scale model for the diazotrophic cyanobacterium, Cyanothece sp. ATCC 51142. The resulting metabolic reconstruction, iCce806, consists of 806 genes associated with 667 metabolic reactions and includes a detailed representation of the ETC and a biomass equation based on experimental measurements. Both computational and experimental approaches were used to investigate light-driven metabolism in Cyanothece sp. ATCC 51142, with a particular focus on reductant production and partitioning within the ETC. The simulation results suggest that growth and metabolic flux distributions are substantially impacted by the relative amounts of light going into the individual photosystems. When growth is limited by the flux through photosystem I, terminal respiratory oxidases are predicted to be an important mechanism for removing excess reductant. Similarly, under photosystem II flux limitation, excess electron carriers must be removed via cyclic electron transport. Furthermore, in silico calculations were in good quantitative agreement with the measured growth rates whereas predictions of reaction usage were qualitatively consistent with protein and mRNA expression data, which we used to further improve the resolution of intracellular flux values

    MRP3: a molecular target for human glioblastoma multiforme immunotherapy.

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    <p>Abstract</p> <p>Background</p> <p>Glioblastoma multiforme (GBM) is refractory to conventional therapies. To overcome the problem of heterogeneity, more brain tumor markers are required for prognosis and targeted therapy. We have identified and validated a promising molecular therapeutic target that is expressed by GBM: human multidrug-resistance protein 3 (MRP3).</p> <p>Methods</p> <p>We investigated MRP3 by genetic and immunohistochemical (IHC) analysis of human gliomas to determine the incidence, distribution, and localization of MRP3 antigens in GBM and their potential correlation with survival. To determine MRP3 mRNA transcript and protein expression levels, we performed quantitative RT-PCR, raising MRP3-specific antibodies, and IHC analysis with biopsies of newly diagnosed GBM patients. We used univariate and multivariate analyses to assess the correlation of RNA expression and IHC of MRP3 with patient survival, with and without adjustment for age, extent of resection, and KPS.</p> <p>Results</p> <p>Real-time PCR results from 67 GBM biopsies indicated that 59/67 (88%) samples highly expressed <it>MRP3 </it>mRNA transcripts, in contrast with minimal expression in normal brain samples. Rabbit polyvalent and murine monoclonal antibodies generated against an extracellular span of MRP3 protein demonstrated reactivity with defined <it>MRP3</it>-expressing cell lines and GBM patient biopsies by Western blotting and FACS analyses, the latter establishing cell surface MRP3 protein expression. IHC evaluation of 46 GBM biopsy samples with anti-MRP3 IgG revealed MRP3 in a primarily membranous and cytoplasmic pattern in 42 (91%) of the 46 samples. Relative RNA expression was a strong predictor of survival for newly diagnosed GBM patients. Hazard of death for GBM patients with high levels of <it>MRP3 </it>RNA expression was 2.71 (95% CI: 1.54-4.80) times that of patients with low/moderate levels (p = 0.002).</p> <p>Conclusions</p> <p>Human GBMs overexpress MRP3 at both mRNA and protein levels, and elevated MRP3 mRNA levels in GBM biopsy samples correlated with a higher risk of death. These data suggest that the tumor-associated antigen MRP3 has potential use for prognosis and as a target for malignant glioma immunotherapy.</p

    Renewable energy from Cyanobacteria: energy production optimization by metabolic pathway engineering

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    The need to develop and improve sustainable energy resources is of eminent importance due to the finite nature of our fossil fuels. This review paper deals with a third generation renewable energy resource which does not compete with our food resources, cyanobacteria. We discuss the current state of the art in developing different types of bioenergy (ethanol, biodiesel, hydrogen, etc.) from cyanobacteria. The major important biochemical pathways in cyanobacteria are highlighted, and the possibility to influence these pathways to improve the production of specific types of energy forms the major part of this review

    Role of neurotrophin signalling in the differentiation of neurons from dorsal root ganglia and sympathetic ganglia

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    Regionalisation of rainfall depth–duration–frequency curves with different data types in Germany

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    Rainfall depth–duration–frequency (DDF) curves are required for the design of several water systems and protection works. For the reliable estimation of such curves, long and dense observation networks are necessary, which in practice is seldom the case. Usually observations with different accuracy, temporal resolution and density are present. In this study, we investigate the integration of different observation datasets under different methods for the local and regional estimation of DDF curves in Germany. For this purpose, two competitive DDF procedures for local estimation (Koutsoyiannis et al., 1998; Fischer and Schumann, 2018) and two for regional estimation (kriging theory vs. index based) are implemented and compared. Available station data from the German Weather Service (DWD) for Germany are employed, which includes 5000 daily stations with more than 10 years available, 1261 high-resolution (1 min) recordings with an observation period between 10 and 20 years, and finally 133 high-resolution (1 min) recordings with 60–70 years of observations. The performance of the selected approaches is evaluated by cross-validation, where the local DDFs from the long sub-hourly time series are considered the true reference. The results reveal that the best approach for the estimation of the DDF curves in Germany is by first deriving the local extreme value statistics based on Koutsoyiannis et al.'s (1998) framework and later using the kriging regionalisation of long sub-hourly time series with the short sub-hourly time series acting as an external drift. The integration of the daily stations proved to be useful only for DDF values of a low return period (T[a] &lt; 10 years) but does not introduce any improvement for higher return periods (T[a] ≥ 10 years).</p

    Reaction norms of size characters in relation to growth temperature in Drosophila melanogaster: an isofemale lines analysis

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    Ten isofemale lines of Drosophila melanogaster, recently collected in a French vineyard, were submitted to 7 different developmental temperatures, from 12 to 31°C, encompassing the whole physiological range of the species. For each line and temperature, 10 flies of each sex were collected randomly and 2 size-related traits were measured: wing and thorax length. Both traits exhibited similar response curves: a maximum size at a low temperature and a decrease on both sides. ANOVA showed significant variations between lines and also significant line-temperature interactions, demonstrating different norms of reaction among the various lines. The shapes of the curves were further analysed by considering slope variations, ie by calculating empirical derivative curves. The most interesting observation is that the temperature of maximum size (TMS) is not the same for the wing (average 15.73 ± 0.29°C) and the thorax (average 19.57 ± 0.47°C). Genetic differences seem to exist between lines, and TMS for both traits are correlated. Sexual dimorphism was analysed by considering the female/male ratio for wing and thorax. Both traits provided the same information: sexual dimorphism increased, from 1.10 to 1.16, with increasing temperature, and significant differences were found between lines. Finally the wing/thorax ratio appeared as an original and most interesting trait. This ratio, which is less variable than wing or thorax, exhibited a monotonously decreasing sigmoid shape, from 2.80 to 2.40, with increasing temperature. It is suggested that this ratio, which may be related to flight capacity at various temperatures, could be the direct target of natural selection.Dix lignées isofemelles de Drosophila melanogaster, récemment récoltées dans un vignoble français du sud-ouest de la France, ont été soumises à 7 températures différentes (de 12 à 31°C) compatibles avec le développement de l’espèce. Pour chaque Lignée et chaque température, 10 mouches de chaque sexe ont été choisies au hasard. Sur chaque individu, 2 caractères relatifs à la taille ont été mesurés : la longueur de l’aile et la longueur du thorax. Les courbes de réponse des 2 caractères ont la même forme et mettent en évidence une taille maximum en dessous de 20°C et une décroissance de part et d’autre de ce maximum. Des variations significatives entre les lignées de même que des interactions significatives lignée-température sont mises en évidence par ANOVA, ce qui montre que les normes de réaction des différentes lignées ont des formes différentes. L’analyse de la forme des courbes a été réalisée en considérant les variations des pentes pour chaque intervalle de température, c’est-à-dire en calculant empiriquement une dérivée. L’observation la plus remarquable concerne la température pour laquelle la taille est maximale: 15, 73 ± 0, 29°C pour l’aile et 19, 57 ± 0, 47°C pour le thorax. Des différences génétiques entre les lignées sont mises en évidence pour cette température de taille maximum, et les valeurs obtenues pour les 2 caractères sont corrélées. Le rapport femelle-mâle pour l’aile ou le thorax permet d’étudier le dimorphisme sexuel. Le rapport augmente de 1,10 à 1,16 quand la température passe de 12 à 31° C. Il existe aussi des différences significatives entre les Lignées. Il est montré que le rapport aile-thorax est un critère original et d’un grand intérêt. Ce rapport est relativement moins variable que l’aile ou le thorax. Il décroît selon une sigmoïde à mesure que la température augmente et varie de 2,80 à 2,40. Vraisemblablement en relation avec la capacité de vol en fonction de la température, le rapport aile-thorax pourrait être la cible directe de la sélection naturelle
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