1,721,566 research outputs found
Stability properties of stochastic maximal Lp-regularity
No full textIn this paper we consider Lp-regularity estimates for solutions to stochastic evolution equations, which is called stochastic maximal Lp-regularity. Our aim is to find a theory which is analogously to Dore’s theory for deterministic evolution equations. He has shown that maximal Lp-regularity is independent of the length of the time interval, implies analyticity and exponential stability of the semigroup, is stable under perturbation and many more properties. We show that the stochastic versions of these results hold
HMG proteins: dynamic players in gene regulation and differentiation
No full textCore histones package the genome into nucleosomes andcontrol its accessibility to transcription factors. High mobilitygroup proteins (HMGs) are, after histones, the second mostabundant chromatin proteins and exert global genomicfunctions in establishing active or inactive chromatin domains.It is becoming increasingly clear that they also specificallycontrol the expression of a limited number of genes. Moreover,they contribute to the fine tuning of transcription in response torapid environmental changes. They do so by interacting withnucleosomes, transcription factors, nucleosome-remodellingmachines, and with histone H1
de Caprariis D., Gravino A.E., Cerundolo R., Manna L.,Agresti A. Prime osservazioni in Europa di infezione associata a Rickettsia rickettsii nel cane: Descrizione di 10 casi
No full textReflections on Murray Aitkin's contributions to nonparametric mixture models and Bayes factors
No full textWe describe two interesting and innovative strands of Murray Aitkin's research publications, dealing with mixture models and with Bayesian inference. Of his considerable publications on mixture models, we focus on a nonparametric random effects approach in generalized linear mixed modelling, which has proven useful in a wide variety of applications. As an early proponent of ways of implementing the Bayesian paradigm, Aitkin proposed an alternative Bayes factor based on a posterior mean likelihood. We discuss these innovative approaches and some research lines motivated by them and also suggest future related methodological implementations
A simple model of NF-kappaB dynamics reproduces experimental observations
No full textThe mathematical modeling of the NF-κB oscillations has attracted considerable attention in recent times, but there is a lack of simple models in the literature that can capture the main features of the dynamics of this important transcription factor. For this reason we propose a simple model that summarizes the key steps of the NF-κB pathway. We show that the resulting 5-dimensional dynamical system can reproduce different phenomena observed in experiments. Our model can display smooth and spiky oscillations in the amount of nuclear NF-κB and can reproduce the variety of dynamics observed when different stimulations such as TNF-α and LPS are used. Furthermore we show that the model can be easily extended to reproduce the expression of early, intermediate and late genes upon stimulation. As a final example we show that our simple model can mimic the different transcriptional outputs observed when cells are treated with two different drugs leading to nuclear localization of NF-κB: Leptomycin B and Cycloheximide
High-throughput analysis of NF-κB dynamics in single cells reveals basal nuclear localization of NF-κB and spontaneous activation of oscillations
No full textNF-kB is a transcription factor that upon activation undergoes cycles of cytoplasmic-to-nuclear and nuclear-to-cytoplasmictransport, giving rise to so called ‘‘oscillations’’. In turn, oscillations tune the transcriptional output. Since a detailedunderstanding of oscillations requires a systems biology approach, we developed a method to acquire and analyze largevolumes of data on NF-kB dynamics in single cells. We measured the time evolution of the nuclear to total ratio of GFP-p65in knock-in mouse embryonic fibroblasts using time-lapse imaging. We automatically produced a precise segmentation ofnucleus and cytoplasm based on an accurate estimation of the signal and image background. Finally, we defined a set ofquantifiers that describe the oscillatory dynamics, which are internally normalized and can be used to compare datarecorded by different labs. Using our method, we analyzed NF-kB dynamics in over 2000 cells exposed to differentconcentrations of TNF- a a. We reproduced known features of the NF-kB system, such as the heterogeneity of the responsein the cell population upon stimulation and we confirmed that a fraction of the responding cells does not oscillate. We alsounveiled important features: the second and third oscillatory peaks were often comparable to the first one, a basal amountof nuclear NF-kB could be detected in unstimulated cells, and at any time a small fraction of unstimulated cells showedspontaneous random activation of the NF-kB system. Our work lays the ground for systematic, high-throughput, andunbiased analysis of the dynamics of transcription factors that can shuttle between the nucleus and other cellcompartments
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Laser processing optimization for large-area perovskite solar modules
Full text linkThe industrial exploitation of perovskite solar cell technology is still hampered by the lack of repeatable and high-throughput fabrication processes for large-area modules. The joint efforts of the scientific community allowed to demonstrate high-performing small area solar cells; however, retaining such results over large area modules is not trivial. Indeed, the development of deposition methods over large substrates is required together with additional laser processes for the realization of the monolithically integrated cells and their interconnections. In this work, we develop an efficient perovskite solar module based on 2D material engineered structure by optimizing the laser ablation steps (namely P1, P2, P3) required for shaping the module layout in series connected sub-cells. We investigate the impact of the P2 and P3 laser processes, carried out by employing a UV pulsed laser (pulse width = 10 ns; lambda = 355 nm), over the final module performance. In particular, a P2 process for removing 2D material-based cell stack from interconnection area among adjacent cells is optimized. Moreover, the impact of the P3 process used to isolate adjacent sub-cells after gold realization over the module performance once laminated in panel configuration is elucidated. The developed fabrication process ensures high-performance repeatability over a large module number by demonstrating the use of laser processing in industrial production
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