436 research outputs found
Molecular Profiling of Lymphatic Endothelial Cell Activation In Vitro
The lymphatic vascular system plays a key role in cancer progression. Indeed, the activation of lymphatic endothelial cells (LECs) through the lymphangiogenic process allows for the formation of new lymphatic vessels (LVs) that represent the major route for the dissemination of solid tumors. This process is governed by a plethora of cancer-derived and microevironmental mediators that strictly activate and control specific molecular pathways in LECs. In this work we used an in vitro model of LEC activation to trigger lymphangiogenesis using a mix of recombinant pro-lymphangiogenic factors (VFS) and a co-culture system with human melanoma cells. Both systems efficiently activated LECs, and under these experimental conditions, RNA sequencing was exploited to unveil the transcriptional profile of activated LECs. Our data demonstrate that both recombinant and tumor cell-mediated activation trigger significant molecular pathways associated with endothelial activation, morphogenesis, and cytokine-mediated signaling. In addition, this system provides information on new genes to be further investigated in the lymphangiogenesis process and open the possibility for further exploitation in other tumor contexts where lymphatic dissemination plays a relevant role
Discriminating chaotic and stochastic time series using permutation entropy and artificial neural networks
Extracting relevant properties of empirical signals generated by nonlinear,
stochastic, and high-dimensional systems is a challenge of complex systems
research. Open questions are how to differentiate chaotic signals from
stochastic ones, and how to quantify nonlinear and/or high-order temporal
correlations. Here we propose a new technique to reliably address both
problems. Our approach follows two steps: first, we train an artificial neural
network (ANN) with flicker (colored) noise to predict the value of the
parameter, , that determines the strength of the correlation of the
noise. To predict the ANN input features are a set of probabilities
that are extracted from the time series by using symbolic ordinal analysis.
Then, we input to the trained ANN the probabilities extracted from the time
series of interest, and analyze the ANN output. We find that the value
returned by the ANN is informative of the temporal correlations present in the
time series. To distinguish between stochastic and chaotic signals, we exploit
the fact that the difference between the permutation entropy (PE) of a given
time series and the PE of flicker noise with the same parameter is
small when the time series is stochastic, but it is large when the time series
is chaotic. We validate our technique by analysing synthetic and empirical time
series whose nature is well established. We also demonstrate the robustness of
our approach with respect to the length of the time series and to the level of
noise. We expect that our algorithm, which is freely available, will be very
useful to the community
Small changes at single nodes can shift global network dynamics
Understanding the sensitivity of a system's behavior with respect to
parameter changes is essential for many applications. This sensitivity may be
desired - for instance in the brain, where a large repertoire of different
dynamics, particularly different synchronization patterns, is crucial - or may
be undesired - for instance in power grids, where disruptions to
synchronization may lead to blackouts. In this work, we show that the dynamics
of networks of phase oscillators can acquire a very large and complex
sensitivity to changes made in either their units' parameters or in their
connections - even modifications made to a parameter of a single unit can
radically alter the global dynamics of the network in an unpredictable manner.
As a consequence, each modification leads to a different path to phase
synchronization manifested as large fluctuations along that path. This
dynamical malleability occurs over a wide parameter region, around the
network's two transitions to phase synchronization. One transition is induced
by increasing the coupling strength between the units, and another is induced
by increasing the prevalence of long-range connections. Specifically, we study
Kuramoto phase oscillators connected under either Watts-Strogatz or
distance-dependent topologies to analyze the statistical properties of the
fluctuations along the paths to phase synchrony. We argue that this increase in
the dynamical malleability is a general phenomenon, as suggested by both
previous studies and the theory of phase transitions.Comment: 14 pages, 8 figure
Spatial permutation entropy distinguishes resting brain states
We use ordinal analysis and spatial permutation entropy to distinguish between eyes-open and eyes-closed resting brain states. To do so, we analyze EEG data recorded with 64 electrodes from 109 healthy subjects, under two one-minute baseline runs: One with eyes open, and one with eyes closed. We use spatial ordinal analysis to distinguish between these states, where the permutation entropy is evaluated considering the spatial distribution of electrodes for each time instant. We analyze both raw and post-processed data considering only the alpha-band frequency (8–12 Hz) which is known to be important for resting states in the brain. We conclude that spatial ordinal analysis captures information about correlations between time series in different electrodes. This allows the discrimination of eyes closed and eyes open resting states in both raw and filtered data. Filtering the data only amplifies the distinction between states. Importantly, our approach does not require EEG signal pre-processing, which is an advantage for real-time applications, such as brain-computer interfaces.B.R.R.B. and E.E.N.M. acknowledge support of São Paulo Research Foundation (FAPESP), Brazil, Proc. 2018/03211-6 and 2021/09839-0; and Financiadora de Estudos e Projetos (FINEP), Brazil. R.C.B. acknowledges support of Western Institute for Neuroscience Clinical Research Postdoctoral Fellowship and Western Academy for Advanced Research. K.L.R. acknowledges supported of German Academic Exchange Service (DAAD). C.M. acknowledges support of Ministerio de Ciencia, Innovación ������ Universidades (PID2021-123994NB-C21), Spain and Institució Catalana de Recerca i Estudis Avançats (ICREA), Spain.Peer ReviewedPostprint (published version
Cana-de-açúcar cultivada em solo adubado com lodo de esgoto: nutrientes, metais pesados e produtividade.
A pesquisa objetivou avaliar o uso de lodo de esgoto (Le) na adubação de soqueira (2o corte) de cana-de-açúcar (Saccharum spp., var. RB72-454). Aplicou-se Le ao solo, localizando-o no fundo de um sulco com 15 cm de profundidade e distando 40 cm da linha de cana. Avaliaram-se os efeitos das doses do Le (0, 15 e 30 t.ha-1) nas produtividades de biomassa e de açúcar, nos teores de nutrientes e de metais pesados do solo e da planta. O Le diminuiu a acidez potencial (H + Al) do solo e forneceu nutrientes para a cana-de-açúcar, principalmente P, S, Ca, Cu e Zn, o que refletiu em aumentos de produtividades de colmos e de açúcar por hectare. O Le causou aumentos de exportações de P, S, Ca, Cu, K, Mg e Ni pela parte aérea da cana-de-açúcar; tais aumentos, por sua vez, foram motivados pelos aumentos dos teores destes elementos no tecido vegetal, e da produtividade em biomassa. Os metais pesados (Cd, Cr, Ni e Pb), contidos no Le, não apresentaram perigo à cadeia trófica à curto prazo
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Structural Characterization of Charcoal Exposed to High and Low pH: Implications for 14C Sample Preparation and Charcoal Preservation
Chemical and structural similarities between poorly preserved charcoal and its contaminants, as well as low radiocarbon concentrations in old samples, complicate 14C age determinations. Here, we characterize 4 fossil charcoal samples from the late Middle Paleolithic and early Upper Paleolithic strata of Kebara Cave, Israel, with respect to the structural and chemical changes that occur when they are subjected to the acid-base-acid (ABA) treatment. Differential thermal analysis and TEM show that acid treatment disrupts the structure, whereas alkali treatment results in the reformation of molecular aggregates. The major changes are ascribed to the formation of salt bridges at high pH and the disruption of the graphite-like crystallites at low pH. Weight losses during the treatments are consistently greater for older samples, implying that they are less well preserved. Based on the changes observed in vitro due to pH fluctuations, various methods for removing contamination, as well as a mechanism for preferential preservation of charcoal in nature, are proposed.Anthropolog
ISOTOPES, PLANTS, AND RESERVOIR EFFECTS: CASE STUDY FROM THE CASPIAN STEPPE BRONZE AGE
ISOTOPES, PLANTS, AND RESERVOIR EFFECTS Shishlina, N.; Zazovskaya, E.; van der Plicht, J.; Sevastyanov, V.; Boaretto, E.; Rebollo Franco, N.R. Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons). Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. ABSTRACT. Bronze Age human and animal bone collagen from several steppe Bronze Age cultures (i.e. Early Catacomb, East and West Manych Catacomb, and Lola cultures) shows large variations in 13 C and 15 N values. In general, we observed that the older the sample, the lower the 13 C and 15 N values. We hypothesize that more positive values of 13 C and 15 N are caused by change in diet and a more arid climate. For ancient sheep during drier periods of the Early Catacomb, East and West Manych Catacomb, and Lola cultures, we observed 2 groups with different C and N isotopic compositions, reflecting consumption of different types of fodder. During periods of aridization, C 4 and C 3 plants with high 15 N values appeared in the vegetation, also influencing bone collagen values. Human bones show reservoir effects, caused by aquatic diet components. These effects can be quantified by paired dating of human bone and associated terrestrial samples. Reservoir corrections have revised chronologies for the region. Some paired dates do not reveal reservoir effects. This can be explained in 2 alternative ways. One is that the human diet did not include aquatic components; rather, the diet was based on C 3 vegetation with high 15 N values (13-15‰), and flesh/milk of domesticated animals. An alternative explanation is that humans consumed food from freshwater resources without reservoir effects
Dispersão de machos estéreis de Ceratitis capitata (Wied.) em pomar comercial de manga (Mangifera indica L.) na região Sudoeste da Bahia.
O cultivo de manga é a principal opção econômica do pólo de fruticultura de Anagé, Região Sudoeste da BA. As moscas-das-frutas são pragas quarentenárias e se constituem nos principais problemas fitossanitários da região. Em conformidade com os princípios da Produção Integrada de Frutas, a Técnica do Inseto Estéril (TIE) apresenta-se como uma estratégia de manejo vantajosa e de baixo impacto ambiental. Estudos sobre dispersão de moscamed (Ceratitis capitata Wied.) estéril são necessários para gerar subsídios à implantação da TIE no Brasil. Esse trabalho teve por objetivos estimar a capacidade de dispersão de machos moscamed estéril em pomar comercial de manga e a sua sobrevivência em campo. Cerca de 18.000 machos estéreis de moscamed, linhagem TSL Viena 8, procedentes de Mendonza, Argentina, foram liberados no centro do pomar de 20 ha, às 06h00. Para a recaptura, foram utilizadas armadilhas Jackson, dispostas a cada 25m nas direções N, S, L, O, NO, NE. SO e SE, totalizando 80 armadilhas, num raio máximo de 250 m. No 1º, 3º, 5º, 7º, 9º e 11º dia da liberação, as armadilhas foram expostas às 8h00 e retiradas após uma hora, sendo levadas a uma sala escura, sob lâmpada negra, para contagem de machos estéreis e selvagens. Foram recapturados apenas 22 machos estéreis (0,12%) em 16 armadilhas (20,0%) no primeiro dia após a liberação, sendo que nos demais dias a recaptura foi nula. As recapturas ocorreram principalmente nas armadilhas a sudoeste do ponto de liberação, à distância mínima de 25 metros (SO, NE, NO, SE) e máxima de 250 metros (S). Boa parte dos adultos (40%) foi recapturada num raio de 50m do ponto de liberação. A distância média de dispersão foi de 157,0 m/dia e a área abrangida foi de 29.008,33 m²/dia. A sobrevivência dos machos em campo foi insatisfatóri
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