Influence of the Multidecadal Atlantic Meridional Overturning Circulation Variability on European Climate

The influence of the natural multidecadal variability of the Atlantic meridional overturning circulation (MOC) on European climate is investigated using a simulation with the coupled atmosphere–ocean general circulation model ECHAM5/Max Planck Institute Ocean Model (MPI-OM). The results show that Atlantic MOC fluctuations, which go along with changes in the northward heat transport, in turn affect European climate. Additionally, ensemble predictability experiments with ECHAM5/MPI-OM show that the probability density functions of surface air temperatures in the North Atlantic/European region are affected by the multidecadal variability of the large-scale oceanic circulation. Thus, some useful decadal predictability may exist in the Atlantic/European sector

Contact-induced charge contributions to non-local spin transport measurements in Co/MgO/graphene devices

Recently, it has been shown that oxide barriers in graphene-based non-local spin-valve structures can be the bottleneck for spin transport. The barriers may cause spin dephasing during or right after electrical spin injection which limit spin transport parameters such as the spin lifetime of the whole device. An important task is to evaluate the quality of the oxide barriers of both spin injection and detection contacts in a fabricated device. To address this issue, we discuss the influence of spatially inhomogeneous oxide barriers and especially conducting pinholes within the barrier on the background signal in non-local measurements of graphene/MgO/Co spin-valve devices. By both simulations and reference measurements on devices with non-ferromagnetic electrodes, we demonstrate that the background signal can be caused by inhomogeneous current flow through the oxide barriers. As a main result, we demonstrate the existence of charge accumulation next to the actual spin accumulation signal in non-local voltage measurements, which can be explained by a redistribution of charge carriers by a perpendicular magnetic field similar to the classical Hall effect. Furthermore, we present systematic studies on the phase of the low frequency non-local ac voltage signal which is measured in non-local spin measurements when applying ac lock-in techniques. This phase has so far widely been neglected in the analysis of non-local spin transport. We demonstrate that this phase is another hallmark of the homogeneity of the MgO spin injection and detection barriers. We link backgate dependent changes of the phase to the interplay between the capacitance of the oxide barrier to the quantum capacitance of graphene.Comment: 19 pages, 7 figure

Drug delivery to the brain: How can nanoencapsulated statins be used in the clinic?

© 2017 Future Science Ltd. Statins are used for the primary and secondary prevention of cardiovascular disease by inhibiting cholesterol synthesis in the liver. Statins have also noncholesterol-related effects, called pleiotropic effects, which arise from statins' anti-inflammatory, immunomodulatory and antioxidant properties. These effects are especially attractive for the treatment of various brain diseases ranging from stroke to neurodegenerative diseases. Still, low brain concentrations after oral drug administration hinder the clinical application of statins in these pathologies. Pharmaceutical nanotechnologies may offer a solution to this problem, as local or targeted delivery of nanoencapsulated statins may increase brain availability. This special report rapidly summarizes the potential of statins in the treatment of brain diseases and the pharmaceutical nanotechnologies that could provide a viable approach to enable these indications

Expression of DC-SIGN and DC-SIGNR on human sinusoidal endothelium: a role for capturing hepatitis C virus particles.

Hepatic sinusoidal endothelial cells are unique among endothelial cells in their ability to internalize and process a diverse range of antigens. DC-SIGNR, a type 2 C-type lectin expressed on liver sinusoids, has been shown to bind with high affinity to hepatitis C virus (HCV) E2 glycoprotein. DC-SIGN is a closely related homologue reported to be expressed only on dendritic cells and a subset of macrophages and has similar binding affinity to HCV E2 glycoprotein. These receptors function as adhesion and antigen presentation molecules. We report distinct patterns of DC-SIGNR and DC-SIGN expression in human liver tissue and show for the first time that both C-type lectins are expressed on sinusoidal endothelial cells. We confirmed that these receptors are functional by demonstrating their ability to bind HCV E2 glycoproteins. Although these lectins on primary sinusoidal cells support HCV E2 binding, they are unable to support HCV entry. These data support a model where DC-SIGN and DC-SIGNR on sinusoidal endothelium provide a mechanism for high affinity binding of circulating HCV within the liver sinusoids allowing subsequent transfer of the virus to underlying hepatocytes, in a manner analogous to DC-SIGN presentation of human immunodeficiency virus on dendritic cells

Physicochemical characterization of a hydrophilic model drug-loaded PHBV microparticles obtained by the double emulsion/solvent evaporation technique

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Improved seasonal prediction of European summer temperatures with new five-layer soil-hydrology scheme

We evaluate the impact of a new 5-layer soil-hydrology scheme on seasonal hindcast skill of 2-meter temperatures over Europe obtained with the Max Planck Institute Earth System Model (MPI-ESM). Assimilation experiments from 1981 to 2010 and 10-member seasonal hindcasts initialized on 1 May each year are performed with MPI-ESM in two soil configurations, one using a bucket scheme and one a new 5-layer soil-hydrology scheme. We find the seasonal hindcast skill for European summer temperatures to improve with the 5-layer scheme compared to the bucket scheme, and investigate possible causes for these improvements. First, improved indirect soil moisture assimilation allows for enhanced soil moisture-temperature feedbacks in the hindcasts. Additionally, this leads to improved prediction of anomalies in the 500 hPa geopotential height surface, reflecting more realistic atmospheric circulation patterns over Europe

The materiality of digital media: The hard disk drive, phonograph, magnetic tape and optical media in technical close-up

Popular discourses surrounding contemporary digital media often misrepresent it as immaterial and ephemeral, overlooking the material devices that store and generate our media objects. This article materially ‘descends’ into a selection of prior media forms that make up the genealogy of the hard disk drive (HDD) to challenge our reliance on conceptual misrepresentations. This material analysis is used to situate digital media in a genealogy of prior media forms, to enrich our understanding of how media’s affordances arise from the interplay of both formal and forensic materiality and to demonstrate the value of reintegrating materiality back into the study of media

Use of groundwater lifetime expectancy for the performance assessment of a deep geologic waste repository: 1. Theory, illustrations, and implications

Long-term solutions for the disposal of toxic wastes usually involve isolation of the wastes in a deep subsurface geologic environment. In the case of spent nuclear fuel, if radionuclide leakage occurs from the engineered barrier, the geological medium represents the ultimate barrier that is relied upon to ensure safety. Consequently, an evaluation of radionuclide travel times from a repository to the biosphere is critically important in a performance assessment analysis. In this study, we develop a travel time framework based on the concept of groundwater lifetime expectancy as a safety indicator. Lifetime expectancy characterizes the time that radionuclides will spend in the subsurface after their release from the repository and prior to discharging into the biosphere. The probability density function of lifetime expectancy is computed throughout the host rock by solving the backward-in-time solute transport adjoint equation subject to a properly posed set of boundary conditions. It can then be used to define optimal repository locations. The risk associated with selected sites can be evaluated by simulating an appropriate contaminant release history. The utility of the method is illustrated by means of analytical and numerical examples, which focus on the effect of fracture networks on the uncertainty of evaluated lifetime expectancy.Comment: 11 pages, 8 figures; Water Resources Research, Vol. 44, 200

Myocardial effective transverse relaxation time T(2)* correlates with left ventricular wall thickness: a 7.0 T MRI study

PURPOSE: Myocardial effective relaxation time T2* is commonly regarded as a surrogate for myocardial tissue oxygenation. However, it is legitimate to assume that there are multiple factors that influence T2*. To this end, this study investigates the relationship between T2* and cardiac macromorphology given by left ventricular (LV) wall thickness and left ventricular radius, and provides interpretation of the results in the physiological context. METHODS: High spatio-temporally resolved myocardial CINE T2* mapping was performed in 10 healthy volunteers using a 7.0 Tesla (T) full-body MRI system. Ventricular septal wall thickness, left ventricular inner radius, and T2* were analyzed. Macroscopic magnetic field changes were elucidated using cardiac phase-resolved magnetic field maps. RESULTS: Ventricular septal T2* changes periodically over the cardiac cycle, increasing in systole and decreasing in diastole. Ventricular septal wall thickness and T2* showed a significant positive correlation, whereas the inner LV radius and T2* were negatively correlated. The effect of macroscopic magnetic field gradients on T2* can be considered minor in the ventricular septum. CONCLUSION: Our findings suggest that myocardial T2* is related to tissue blood volume fraction. Temporally resolved T2* mapping could be beneficial for myocardial tissue characterization and for understanding cardiac (patho)physiology in vivo