The calculation of core level shifts can be done in the context of density functional theory (DFT) using different approaches and physical approximations to the photoemission process. The initial ...state and the
Δ
SCF approximations are the most commonly used ones. Here, we describe the details of their implementation in the context of DFT using pseudopotentials and localized atomic orbitals as a basis set, and in particular as applied to the Siesta code. We give a full account of the technicalities involved in these calculations, including the details of the ionic pseudopotential generation, basis sets, charge states and reference potential. We test the method by computing the core level shifts of the Si 2
p
level for a series of molecules and the
p
(2 × 2) asymmetric-dimer reconstruction of the Si(001) surface.
The Ría de Vigo (NW Spain) has a high organic matter content and high rates of sedimentation. The microbial degradation of this organic matter has led to shallow gas accumulations of methane, ...currently distributed all along the ría. These peculiar characteristics favor the development of anoxic conditions that can determine the dynamics of iron and manganese.
In order to study the role played by iron and manganese in the processes that take place in anoxic sediments with shallow gas, four gravity cores were retrieved in anoxic sediments of the Ría de Vigo in November 2012. Methane was present in two of them, below 90cm in the inner zone and below 200cm, in the outer zone. Pore water was collected and analyzed for vertical profiles of pH, sulfide, sulfate, iron and manganese concentrations. Sulfate concentrations decreased with depth but never reached the minimum detection limit. High sulfide concentrations were measured in all cores. The highest sulfide concentrations were found in the inner zone with methane and the lowest were in the outer zone without methane. Concentrations of iron and manganese reached maximum values in the upper layers of the sediment, decreasing with depth, except in the outer zone without gas, where iron and manganese concentration increased strongly toward the bottom of the sediment.
In areas with shallow gas iron reduction, sulfate reduction and methane production processes coexist, showing that the traditional redox cascade is highly simplified and suggesting that iron may be involved in a cryptic sulfur cycle and in the oxidation of methane.
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•We discussed the redox processes in pore water of anoxic sediments shallow gas.•A different behavior of Fe and Mn among cores with and without methane was observed.•In cores with gas iron and sulfate reduction coexisted in the methanogenic zone.•In the shallow gas sediments the redox hierarchy differs from the conventional one.•The “cryptic sulfur cycle” might explain the difference between cores.
The major problem in drug delivery to the brain is the presence of the blood–brain barrier (BBB) which limits drug penetration even if in certain pathological situations the BBB is partly disrupted. ...Therefore, various strategies have been proposed to improve the delivery of drugs to this tissue. This review presents the status of the BBB in healthy patients and in pathologies like neurodegenerative, cerebrovascular and inflammatory diseases. The second part of this article aims to review the invasive and non-invasive strategies developed to circumvent the BBB and deliver drugs into the brain. The use of nanotechnologies (liposomes, nanoparticles) is especially discussed in the ultimate part of the review evidencing their potentiality as non-invasive technique in the brain delivery of drugs with the possibility to target specific brain tissue thanks to ligand linked to carrier surface.
•Integrating seismic, lithological, analytical, chronological and palynological data.•High-resolution spatial–temporal changes in RSL using subtidal sediments.•Tracing of deposits from ephemeral ...ponds and high marshes to study sea-level changes.•Several short climatic reverses recognised between the LGM and the Early Holocene.•In the 8.2 event the RSL remained between −19.8/−12.6 m below present sea level.
The Ría de Ferrol is a confined tide-dominated incised valley in the mesotidal passive Atlantic margin of NW Iberia. A new multidisciplinary approach enables a high-resolution reconstruction of the main environmental changes affecting this area during the Lateglacial and the Holocene. We defined the main seismic and sedimentary facies in the infill and selected different key points to be cored. A number of multiproxy analyses were performed on four sections of sediment (sedimentology, X-ray fluorescence, radiocarbon dating and palynological analyses). Physiography exerted a strong control on the evolution of the basin, as a rock-bounded narrow channel in the middle of the basin influenced the flooding of the ria during the postglacial marine transgression. Depositional environments shifted towards the east as the sea level rose and fluvial facies at the base were covered by facies from a tide-dominated estuary, which were predominant during most of the Holocene. Several layers of sediments from stagnant freshwater areas dominated by Juncus sp. were recovered at ca. −20.5 to −21, ca. −13.1 to −13.5, −12.5 to −12.8 and −12.1 to −13.5 m NMMA along the central axis of the embayment, and dated to be older than 10190–10290; 10790–10970; 7510–8220 and 7130–7830 cal yr BP. They may respectively represent a local stage of lowering sea-level dated at the end of the Lateglacial (i.e. the Younger Dryas), and different episodes of deceleration/stabilization of sea-level rise occurred during the early Holocene (i.e. the 11.4, 10.5, 9.3, 8.2 kyr Henrich events). Thus, for the first time in this region, we were able to generate a high-resolution spatial–temporal interpretation of environmental changes linked to the relative sea-level variations using subtidal sediments from the same sub-basin (and thus free of substantial/differential post-depositional deformations) that describes in detail the flooding of the ancient coastal plains of this region at the beginning of the Holocene.
Seismic data have been used to investigate the stratigraphy of the Galician rias for more than two decades. Here, we present a new interpretation of the sedimentary infill of an incised valley (Ría ...de Vigo, NW Iberian Peninsula), based on high-resolution seismic profiles, core sediment analysis, and radiocarbon 14C data. The new data indicate that the stratigraphic architecture of the Galician rias result from multiple incision/infill phases and, therefore, they are reclassified as compound rather than simple incised valleys. Seven seismic units were identified: one of Tertiary age (U1), four of Pleistocene age (U2–U5) which are interpreted as 4th-order sequences deposited between MIS 11 and MIS 2, and Late Pleistocene (U6) and Holocene (U7) units corresponding with post-glacial sedimentation.
The sedimentary infill overlies a highly faulted irregular granitic and metamorphic basement; the inherited morphology is shown to be important for controlling the pathway and evolution of the fluvial network as well as preservation of the sedimentary deposits during several glacial/interglacial cycles. The presence of a rocky barrier at the mouth of the ria is a distinctive feature that conditions sedimentation and exchange of sediment between the ria and the adjacent shelf. For the first time, faults and tilted blocks affecting Late Pleistocene (MIS 3) deposits have been identified.
The new data presented here provide the opportunity to reconstruct the evolution of the sedimentary infill of a ria, with especially high-resolution during the last post-glacial transgression.
•Seismic and core data allow reconstruct the stratigraphic architecture of the ria.•The stratigraphic architecture is consequence of multiple phases of incision/infill during Quaternary.•The basement topography has conditioned the fluvial network and sedimentation along the ria.
Background and Purpose
cAMP plays an important role in the transduction of signalling pathways involved in neuroprotection and immune regulation. Control of the levels of this nucleotide by ...inhibition of cAMP‐specific PDEs such as PDE7 may affect the pathological processes of neuroinflammatory diseases like multiple sclerosis (MS). In the present study, we evaluated the therapeutic potential of the selective PDE7 inhibitor, TC3.6, in a model of primary progressive multiple sclerosis (PPMS), a rare and severe variant of MS.
Experimental Approach
Theiler's murine encephalomyelitis virus‐induced demyelinated disease (TMEV‐IDD) is one of the models used to validate the therapeutic efficacy of new drugs in MS. As recent studies have analysed the effect of PDE7 inhibitors in the EAE model of MS, here the TMEV‐IDD model was used to test their efficacy in a progressive variant of MS. Mice were subjected to two protocols of TC3.6 administration: on the pre‐symptomatic phase and once the disease was established.
Key Results
Treatment with TC3.6 ameliorated the disease course and improved motor deficits of infected mice. This was associated with down‐regulation of microglial activation and reduced cellular infiltrates. Decreased expression of pro‐inflammatory mediators such as COX‐2 and the cytokines, IL‐1β, TNF‐α, IFN‐γ and IL‐6 in the spinal cord of TMEV‐infected mice was also observed after TC3.6 administration.
Conclusion
These findings support the importance of PDE7 inhibitors, and specifically TC3.6, as a novel class of agents with therapeutic potential for PPMS. Preclinical studies are needed to determine whether their effects translate into durable clinical benefits.
We report a combined experimental and theoretical study of the modulation of surface charge transfer on the tetrathiafulvalene (TTF)/Au(111) interface as a function of coverage in the submonolayer ...regime by combining low-temperature scanning tunneling microscopy, high-resolution photoemission spectroscopy using synchrotron radiation, and density functional theory (DFT) calculations. The modulation is induced by the competition between long-range repulsive Coulombic interactions and short-range attractive hydrogen-bonding interactions. The system shows the characteristic pattern evolution, from monomeric stripes at low coverages to two-dimensional islands, with the formation of labyrinths in the crossover.
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