779 research outputs found
Late Pleistocene and Holocene palaeoenvironments in and around the middle Caspian basin as reconstructed from a deep-sea core
This article has been made available through Open Access by the Brunel Open Access Publishing Fund.Late Pleistocene and/or Holocene high-resolution palynological studies are available for the south basin of the Caspian Sea (CS), the world's largest lake. However, the north and middle basins have not been the object of high-resolution palynological reconstructions. This new study presents the pollen, spores and dinoflagellate cysts records obtained from a 10m-long sediment core recovered in the middle basin, which currently has brackish waters and is surrounded by arid and semi-arid vegetation.An age-depth model built based on six radiocarbon dates on ostracod shells indicates that the sequence spans the period from 14.47 to 2.43cal.kaBP. The present palaeoenvironmental study focuses on the top 666cm, or from 12.44 to 2.43cal.kaBP.At the vegetation level, the Younger Dryas is characterised by an open landscape dominated by desert vegetation composed by Amaranthaceae with shrubs and salt-tolerant plants. However, although the Early Holocene is also characterised by desert vegetation, it is enriched in various shrubs such as Ephedra and Calligonum, but tree expansion is not important at the Holocene onset. After a major shift at 8.19cal.kaBP, the Middle Holocene displays now both the character of desert and of steppe, although some trees such as Quercus and Corylus slightly spread. The Late Holocene records steppe vegetation as dominant, with more tree diversity.Regarding the lacustrine signal, the dinocyst assemblage record fluctuates between slightly brackish conditions highlighted by Pyxidinopsis psilata and Spiniferites cruciformis, and more brackish ones - similar to the present day - with the dominance of Impagidinium caspienense. The Late Pleistocene is characterised by low salinities, related to the Khvalynian highstand. From 11.56cal.kaBP, slightly more saline waters are reconstructed with an increase of I.caspienense for a period of 1000 years, which could be attributed to the Mangyshlak lowstand. From 10.55cal.kaBP, low salinity conditions return with remains such as Anabaena and Botryococcus abundant until 8.83cal.kaBP, followed by a slow, progressive decrease of P. psilata and S. cruciformis until 4.11cal.kaBP, which is the main assemblage change at lacustrine scale. Since then, higher salinities, similar to the present one, are reconstructed. Finally, Lingulodinium machaerophorum starts its development only at 2.75cal.kaBP, in the Late Holocene.The present research revealed fundamental differences from previously published sea-level curves, in that a 6000yr-long highstand suggested by low salinities is shown between 10.55 and 4.11cal.kaBP. Amongst other arguments, using a comparison to a similar palynological regard but in the south basin, a N-S salinity gradient that is the reverse of the present one across the CS, suggests that the Amu Darya was flowing in the CS. Hence the CS levels during the Late Pleistocene and Holocene were influenced by a combination of precipitation over the high European latitudes and the indirect influence of the Indian summer monsoon over the Pamirs. © 2014.This study has been conducted within the European Contract INCO-Copernicus “Understanding the Caspian Sea erratic fluctuations” n IC15-CT96-0112. This was funded by the Centre National de la Recherche Scientifique within the framework of the INSUDYTEC (DYnamique de la Terre et du Climat) Program (France)
Reconstructing the impact of human activities in a NW Iberian Roman mining landscape for the last 2500 years
This article was made available through the Brunel Open Access Publishing Fund.Little is known about the impact of human activities during Roman times on NW Iberian mining landscapes beyond the geomorphological transformations brought about by the use of hydraulic power for gold extraction. We present the high-resolution pollen record of La Molina mire, located in an area intensely used for gold mining (Asturias, NW Spain), combined with other proxy data from the same peat core to identify different human activities, evaluate the strategies followed for the management of the resources and describe the landscape response to human disturbances. We reconstructed the timing and synchronicity of landscape changes of varying intensity and form occurred before, during and after Roman times. An open landscape was prevalent during the local Late Iron Age, a period of relatively environmental stability. During the Early Roman Empire more significant vegetation shifts took place, reflected by changes in both forest (Corylus and Quercus) and heathland cover, as mining/metallurgy peaked and grazing and cultivation increased. In the Late Roman Empire, the influence of mining/metallurgy on landscape change started to disappear. This decoupling was further consolidated in the Germanic period (i.e., Visigothic and Sueve domination of the region), with a sharp decrease in mining/metallurgy but continued grazing. Although human impact was intense in some periods, mostly during the Early Roman Empire, forest regeneration occurred afterwards: clearances were local and short-lived. However, the Roman mining landscape turned into an agrarian one at the onset of the Middle Ages, characterized by a profound deforestation at a regional level due to a myriad of human activities that resulted in an irreversible openness of the landscape. © 2014 The Authors
Perinatal exposure to pesticides alters synaptic plasticity signaling and induces behavioral deficits associated with neurodevelopmental disorders.
Increasing evidence from animal and epidemiological studies indicates that perinatal exposure to pesticides cause developmental neurotoxicity and may increase the risk for psychiatric disorders such as autism and intellectual disability. However, the underlying pathogenic mechanisms remain largely elusive. This work was aimed at testing the hypothesis that developmental exposure to different classes of pesticides hijacks intracellular neuronal signaling contributing to synaptic and behavioral alterations associated with neurodevelopmental disorders (NDD). Low concentrations of organochlorine (dieldrin, endosulfan, and chlordane) and organophosphate (chlorpyrifos and its oxon metabolite) pesticides were chronically dosed ex vivo (organotypic rat hippocampal slices) or in vivo (perinatal exposure in rats), and then biochemical, electrophysiological, behavioral, and proteomic studies were performed. All the pesticides tested caused prolonged activation of MAPK/ERK pathway in a concentration-dependent manner. Additionally, some of them impaired metabotropic glutamate receptor-dependent long-term depression (mGluR-LTD). In the case of the pesticide chlordane, the effect was attributed to chronic modulation of MAPK/ERK signaling. These synaptic alterations were reproduced following developmental in vivo exposure to chlordane and chlorpyrifos-oxon, and were also associated with prototypical behavioral phenotypes of NDD, including impaired motor development, increased anxiety, and social and memory deficits. Lastly, proteomic analysis revealed that these pesticides differentially regulate the expression of proteins in the hippocampus with pivotal roles in brain development and synaptic signaling, some of which are associated with NDD. Based on these results, we propose a novel mechanism of synaptic dysfunction, involving chronic overactivation of MAPK and impaired mGluR-LTD, shared by different pesticides which may have important implications for NDD.Open Access funding provided thanks to the
CRUE-CSIC agreement with Springer Nature. This work was
supported by the Intertalentum Postdoctoral Program (Marie
Curie cofund UAM-UE, EU project 713366) for V.B. and by
grants from the Spanish Ministry of Science and Innovation
(SAF2017-86983-R, PID2020-117651RB) and from the Spanish Ministry of Economy and Competitiveness (PCIN-2016–
095) for J.A.E.. V.B. was also recipient of the 2019 Eduardo
Gallego postdoctoral fellowship from Fundación Francisco
Cobos. M.I.C. was recipient of a postdoctoral fellowship from
the Spanish Ministry of Economy (IJCI-2015–25507). E.LM.
was recipient of a predoctoral fellowship from the Spanish
Ministry of Science and Innovation (FPU18/02838).S
Derivada generalizada de Lanczos en una discontinuidad finita
Lanczos introdujo una expresión integral para calcular la derivada de una función, siendo ésta continua en el punto x bajo análisis, Aquí extendemos dicha expresión al caso de una discontinuidad finita en x
Preparation and characterisation of calcined Mg/Al hydrotalcites impregnated with alkaline nitrate and their activities in the combustion of particulate matter
The effect of incorporating alkaline nitrates in hydrotalcites for use in the combustion of particulate matter from diesel emissions has been studied. The catalysts were characterised by X-ray diffraction (XRD), N2 adsorption, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), elemental analysis (EA), atomic absorption spectrophotometry (AAS) temperature programmed reduction (TPR) and Fourier transform infrared spectroscopy (FTIR). Activity measurements were carried out using a thermobalance in air and using a fixed-bed reactor with a NO/O2 flow. The observed activities decreased in the following order: HTMgAlcCs>HTMgAlcK>HTMgAlcLi>HTMgAlc.Centro de Investigación y Desarrollo en Ciencias Aplicada
Whole transcription profile of responders to anti-tnf drugs in pediatric inflammatory bowel disease
Background: Up to 30% of patients with pediatric inflammatory bowel disease (IBD) do not respond to anti-Tumor Necrosis Factor (anti-TNF) therapy. The aim of this study was to identify pharmacogenomic markers that predict early response to anti-TNF drugs in pediatric patients with IBD. Methods: An observational, longitudinal, prospective cohort study was conducted. The study population comprised 38 patients with IBD aged 0.6 or <−0.6 and p value < 0.05). After validation, FCGR1A, FCGR1B, and GBP1 were overexpressed in non-responders two weeks after initiation of anti-TNF treatment (Log2FC 1.05, 1.21, and 1.08, respectively, p value < 0.05). Conclusion: Expression of the FCGR1A, FCGR1B, and GBP1 genes is a pharmacogenomic biomarker of early response to anti-TNF agents in pediatric IBDInstituto de Salud Carlos III número de becas PI16 / 00559 y PI19 / 00792Consejería de Educación y Deporte de la Comunidad de Madrid PEJ16 / MED / AI-1260Instituto de Investigaciones Sanitarias Gregorio Marañón PRE2018-2Fondos Europeos de Desarrollo Regional (FEDER) del Comisión Europe
Preparation of palladium-supported periodic mesoporous organosilicas and their use as catalysts in the Suzuki cross-coupling reaction
Three periodic mesoporous materials, i.e., two organosilicas with either ethylene or phenylene bridges and one silica, have been used as supports for Pd nanoparticles. All Pd-supported samples (1.0 wt%) were prepared by the incipient wetness method and subsequently reduced in an H2 stream at 200 °C. Both hydrogen chemisorption and temperature programmed reduction experiments revealed significant differences depending on the support. Pd2+ species were more reducible on the mesoporous organosilicas than on their silica counterpart. Also, remarkable differences on the particle morphology were observed by transmission electron microscopy. All Pd-supported samples were active in the Suzuki cross-coupling reaction between bromobenzene and phenylboronic acid
Immunometabolism modulation in therapy
The study of cancer biology should be based around a comprehensive vision of the
entire tumor ecosystem, considering the functional, bioenergetic and metabolic state of tumor cells
and those of their microenvironment, and placing particular importance on immune system cells.
Enhanced understanding of the molecular bases that give rise to alterations of pathways related
to tumor development can open up new therapeutic intervention opportunities, such as metabolic
regulation applied to immunotherapy. This review outlines the role of various oncometabolites
and immunometabolites, such as TCA intermediates, in shaping pro/anti-inflammatory activity
of immune cells such as MDSCs, T lymphocytes, TAMs and DCs in cancer. We also discuss the
extraordinary plasticity of the immune response and its implication in immunotherapy efficacy, and
highlight different therapeutic intervention possibilities based on controlling the balanced systems of
specific metabolites with antagonistic functions
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