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Summary: Fine root endophyte mycorrhizal fungi in the Endogonales (Mucoromycota arbuscular mycorrhizal fungi, M‐AMF) are now recognized as at least as important globally as Glomeromycota AMF (G‐AMF), yet little is known about the environmental factors which influence M‐AMF diversity and colonization, partly because they typically only co‐colonize plants with G‐AMF. Wild populations of Lycopodiella inundata predominantly form mycorrhizas with M‐AMF and therefore allow focussed study of M‐AMF environmental drivers. Using microscopic examination and DNA sequencing we measured M‐AMF colonization and diversity over three consecutive seasons and modelled interactions between these response variables and environmental data. Significant relationships were found between M‐AMF colonization and soil S, P, C:N ratio, electrical conductivity, and the previously overlooked micronutrient Mn. Estimated N deposition was negatively related to M‐AMF colonization. Thirty‐nine Endogonales Operational Taxonomic Units (OTUs) were identified in L. inundata roots, a greater diversity than previously recognized in this plant. Endogonales OTU richness correlated negatively with soil C:N while community composition was mostly influenced by soil P. This study provides first evidence that M‐AMF have distinct ecological preferences in response to edaphic variables also related to air pollution. Future studies require site‐level atmospheric pollution monitoring to guide critical load policy for mycorrhizal fungi in heathlands and grasslands. [ABSTRACT FROM AUTHOR]

In a metabolically controlled cross-over experiment, 14 young healthy men's diets were supplemented with beta-glucan in the form of gum oat showed no statistical effect of oat gum on the total blood cholesterol content, or on low-density-lipoprotein cholesterol and triglycerides content. However the high-density-lipoprotein cholesterol content increased. Since the effect of beta-glucan can only be determined by measuring the viscosity of the beta-glucan solutions, the increase in the viscosity of the beta-glucan in the gut might decrease total serum cholesterol levels.

The analysis of dietary fiber (DF) fractions in Airen seedless pomace indicates that DF content is 80% of the dry matter and insoluble DF is constitutes most of this content. Of insoluble DF, glucose is the important neutral sugar present, made up mostly of cellulose with the remaining part constituting xyloglucan, xylose and fucose. In the soluble DF, 64% is uronic acids and the rest is made up of arabinose, galactose and mannose. Sufficient solubilization of polyphenol occurs during the separation of DF fractions.

A first-principles approach based on density functional theory and non-equilibrium Green's functions is used to study the molecular transport system consisting of benzenedithiolate connected with monoatomic gold and platinum electrodes. Using symmetry arguments we explain why the conductance mechanism is different for gold and platinum electrodes. We present the charge stability diagram for the benzenedithiolate connected with monoatomic platinum electrodes including many-body effects in terms of an extended Hubbard Hamiltonian and discuss how the electrodes and the many-body effects influence the transport properties of the system. [ABSTRACT FROM AUTHOR]

Wepresent a general scheme to address correlated nonequilibrium quantum impurity problems based on a mapping onto an auxiliary open quantum system of small size. The infinite fermionic reservoirs of the original system are thereby replaced by a small number NB of noninteracting auxiliary bath sites whose dynamics are described by a Lindblad equation, which can then be exactly solved by numerical methods such as Lanczos or matrix-product states. The mapping becomes exponentially exact with increasing NB, and is already quite accurate for small NB. Due to the presence of the intermediate bath sites, the overall dynamics acting on the impurity site is non-Markovian. While in previous work we put the focus on the manybody solution of the associated Lindblad problem, here we discuss the mapping scheme itself, which is an essential part of the overall approach. Onthe one hand, we provide technical details together with an in-depth discussion of the employed algorithms, and on the other hand, we present a detailed convergence study. The latter clearly demonstrates the above-mentioned exponential convergence of the procedure with increasing NB. Furthermore, the influence of temperature and an external bias voltage on the reservoirs is investigated. The knowledge of the particular convergence behavior is of great value to assess the applicability of the scheme to certain physical situations. Moreover, we study different geometries for the auxiliary system. On the one hand, this is of importance for advanced manybody solution techniques such as matrix product states which work well for short-ranged couplings, and on the other hand, it allows us to gain more insights into the underlying mechanisms when mapping non-Markovian reservoirs onto Lindbladtype impurity problems. Finally, we present results for the spectral function of the Anderson impurity model in and out of equilibrium and discuss the accuracy obtained with the different geometries of the auxiliary system. In particular, we show that allowing for complex Lindblad couplings produces a drastic improvement in the description of the Kondo resonance. [ABSTRACT FROM AUTHOR]

Abstract: Adenosine has been proposed as a homeostatic “sleep factor” that promotes the transition from waking to sleep by affecting several sleep–wake regulatory systems. In the basal forebrain, adenosine accumulates during wakefulness and, when locally applied, suppresses neuronal activity and promotes sleep. However, the neuronal phenotype mediating these effects is unknown. We used whole-cell patch-clamp recordings in in vitro rat brain slices to investigate the effect of adenosine on identified cholinergic and noncholinergic neurons of the magnocellular preoptic nucleus and substantia innominata. Adenosine (0.5–100 μM) reduced the magnocellular preoptic nucleus and substantia innominata cholinergic neuronal firing rate by activating an inwardly rectifying potassium current that reversed at −82 mV and was blocked by barium (100 μM). Application of the A1 receptor antagonist 8-cyclo-pentyl-theophylline (200 nM) blocked the effects of adenosine. Adenosine was also tested on two groups of electrophysiologically distinct noncholinergic magnocellular preoptic nucleus and substantia innominata neurons. In the first group adenosine, via activation of postsynaptic A1 receptors, reduced spontaneous firing via inhibition of the hyperpolarization-activated cation current. Blocking the H-current with ZD7288 (20 μM) abolished adenosine effects on these neurons. The second group was not affected by adenosine. These results demonstrate that, in the magnocellular preoptic nucleus and substantia innominata region of the basal forebrain, adenosine inhibits both cholinergic neurons and a subset of noncholinergic neurons. Both of these effects occur via postsynaptic A1 receptors, but are mediated downstream by two separate mechanisms. [Copyright &y& Elsevier]

We present a numerical study of the doping dependence of the spectral function of the n-type cuprates. Using a variational cluster-perturbation theory approach based upon the self-energy-functional theory, the spectral function of the electron-doped two-dimensional Hubbard model is calculated. The model includes the next-nearest-neighbor electronic hopping amplitude t′ and a fixed on-site interaction U=8t at half-filling and doping levels ranging from x=0.077 to x=0.20. Our results support the fact that a comprehensive description of the single-particle spectrum of electron-doped cuprates requires a proper treatment of strong electronic correlations. In contrast to previous weak-coupling approaches, we obtain a consistent description of the ARPES experiments without the need to (artificially) introduce a doping-dependent on-site interaction U. [ABSTRACT FROM AUTHOR]

Abstract: Adenosine protects neurons during hypoxia by inhibiting excitatory synaptic transmission and preventing NMDA receptor activation. Using an adeno-associated viral (AAV) vector containing Cre recombinase, we have focally deleted adenosine A1 receptors in specific hippocampal regions of adult mice. Recently, we found that deletion of A1 receptors in the CA1 area blocks the postsynaptic responses to adenosine in CA1 pyramidal neurons, and deletion of A1 receptors in CA3 neurons abolishes the presynaptic effects of adenosine on the Schaffer collateral input [J Neurosci 23 (2003) 5762]. In the current study, we used this technique to delete A1 receptors focally from CA3 neurons to investigate whether presynaptic A1 receptors protect synaptic transmission from hypoxia. We studied the effects of prolonged (1 h) hypoxia on the evoked field excitatory postsynaptic potentials (fEPSPs) in the CA1 region using in vitro slices. Focal deletion of the presynaptic A1 receptors on the Schaffer collateral input slowed the depression of the fEPSPs in response to hypoxia and impaired the recovery of the fEPSPs after hypoxia. Delayed responses to hypoxia linearly correlated with impaired recovery. These findings provide direct evidence that the neuroprotective role of adenosine during hypoxia depends on the rapid inhibition of synaptic transmission by the activation of presynaptic A1 receptors. [Copyright &y& Elsevier]

The ventrolateral preoptic nucleus (VLPO) is a key regulator of behavioral state that promotes sleep by directly inhibiting brain regions that maintain wakefulness. Subarachnoid administration of adenosine (AD) or AD agonists promotes sleep and induces expression of Fos protein in VLPO neurons. Therefore, activation of VLPO neurons may contribute to the somnogenic actions of AD. To define the mechanism through which AD activates VLPO neurons, we prepared hypothalamic slices from 9 to 12-day-old rat pups and recorded from 43 neurons in the galaninergic VLPO cluster; nine neurons contained galanin mRNA by post hoc in situ hybridization. Bath application of AD (20 μM) to seven of these neurons had no direct effect but caused a significant decrease in the frequency of spontaneous miniature inhibitory postsynaptic currents in the presence of tetrodotoxin, indicating a presynaptic site of action. We conclude that AD-mediated disinhibition increases the excitability of VLPO neurons thus contributing to the somnogenic properties of AD. [Copyright &y& Elsevier]

Angular-resolved photoemission data on half-filled doped cuprate materials are compared with an exact-diagonalization analysis of the three-band Hubbard model, which is extended to the infinite lattice by means of a perturbation in the intercluster hopping (cluster perturbation theory). A study of the band dispersion and spectral weight of the insulating cuprate Sr 2CuO 2Cl 2 allows us to fix a consistent parameter set, which turns out to be appropriate at finite dopings as well. In the overdoped regime, our results for the spectral weight and for the Fermi surface give a good description of the experimental data on Bi 2Sr 2CaCu 2O 8+δ. In particular, the Fermi surface is hole-like and centered around k=(π, π) . Finally, we introduce a hopping between two layers and address the issue of bilayer splitting. [ABSTRACT FROM AUTHOR]