A new polyborate anion, [B7O9(OH)6]3−: Self assembly, XRD and thermal properties of s-fac-[Co(dien)2][B7O9(OH)6]·9H2O

The title compound, s-fac-[Co(dien)2][B7O9(OH)6]·9H2O (1) (dien = HN(CH2CH2NH2)2), has been prepared as a crystalline solid in moderate yield (35%) from the reaction of B(OH)3 with [Co(dien)2][OH]3 in aqueous solution (10:1 ratio). The structure contains a novel polyborate anion [B7O9(OH)6]3 � which is structurally based on the known �ribbon� isomer of [B7O9(OH)5]2 �, with an additional [OH]� group coordinated to a B atom in one of the outer boroxole rings. Compound 1 is formed by a self-assembly process in which the cation and anion mutually template themselves from equilibrium mixtures under reaction conditions. The [B7O9(OH)6]3 � anions are H-bonded to each other in layers with �cavities� suitable for the [Co(dien]2]3 + complex. Three [B7O9(OH)6]3 � anions are in the secondary coordination sphere (via H-bonds) of each cation, with each anion H-bonded to three cations

Triborate and pentaborate salts of non-metal cations derived from N-substituted piperazines: synthesis, structural (XRD) and thermal properties

The synthesis and characterization of a triborate salt, [H2N(CH2CH2)2NH2][B3O3(OH)4]2 (1), and four pentaborate salts, [H2N(CH2CH2)2NH][B5O6(OH)4] (2a), [MeHN(CH2CH2)2NH][B5O6(OH)4] (2b), [MeHN(CH2CH2)2NMe][B5O6(OH)4] (2c) and [Me2N(CH2CH2)2NMe2][B5O6(OH)4]2 (2d) are described. TGA and DSC analysis (in air, 25�1000 °C) indicate that triborate 1 decomposes to B2O3via a multistage process, with the first stage (<250 °C) being dehydration to condensed polymeric hexaborate of approximate composition: [H2N(CH2CH2)2NH2][B6O10]. The pentaborates (2a�2d) are thermally decomposed to B2O3via a 2 stage process involving polymeric [NMC][B5O8]. The anhydrous polyborates were amorphous. BET analysis of materials derived from the thermolysis of 1 at 250, 400, 600, and 1000 °C, were all non-porous (surface area <1.8 m2 g�1). A single-crystal X-ray diffraction study of 1 showed that it contains isolated triborate(1�) anions in a structure comprised of alternating cationic and anionic layers held together via extensive H-bonds. Single-crystal XRD structural studies on pentaborate salts 2c and 2d are also reported

Synthesis and X-ray structural studies of pentaborate(1−) salts containing substituted imidazolium cations

The preparation of [NMC][B5O6(OH)4] {NMC = 2-MeC3N2H4 (3),1-MeC3N2H4 (4), 4-MeC3N2H4 (5), 1,2-Me2C3N2H3 (6), 1,2,3-Me3C3N2H2 (7), 1-EtC3N2H4 (8), 2-EtC3N2H4 (9), 2-Et-4-MeC3N2H3 (10) 1-Et-3-MeC3N2H3 (11) and 2-iPrC3N2H4 (12)} salts are reported. Compounds were characterised by spectroscopy (NMR and IR) and by single crystal XRD (6, 7, 9, 10, 12) studies. All structures show extensive H-bonded networks and 7 displays the first example of reciprocal paired αααα anion�anion interactions. These are facilitated by the pentaborate boroxole rings being significantly distorted (boat) from the near-planar arrangements more commonly observed. The related imidazolinium salt, [2-MeC3N2H6][B5O6(OH)4] (13), has also been characterised by XRD studies. Compound 13 is isostructural with 3. Thermal properties (TGA/DSC) indicate decomposition to B2O3via [NMC][(B5O8)n] intermediates

Pentaborate(1-) salts templated by substituted pyrrolidinium cations: synthesis, structural characterization, and modelling of solid-state H-bond interactions by DFT calculations

The synthesis and characterization of a series of pentaborate(1�) salts of substituted pyrrolidinium cations [C4H8NH2][B5O6(OH)4] (1), [C4H8NMe2][B5O6(OH)4] (2) [C4H8NMeH][B5O6(OH)4] (3), [(2-CH2OH)C4H7NH2][B5O6(OH)4] (4) is reported. All compounds were characterized by single-crystal XRD studies with 3 (1/2CH3COCH3) and 4 (1/2H2O) solvated. TGA/DSC analysis of the pentaborates 1�4 showed that they thermally decomposed in air at 800 °C to 2.5 B2O3, in a 2 step process involving dehydration (<250 °C) and oxidative decomposition (250�600 °C). BET analysis of materials derived thermally from the pentaborates 1 and 2 had internal porosities of <1 m2 g�1, indicating they were non-porous. All compounds show extensive supramolecular H-bonded anionic lattices. H-bond interactions are described in detail and motifs found in these and in other pentaborate structures have been examined and modelled by DFT calculations. These calculations confirm that H-bonds interactions in pentaborates are moderately strong (ca. �10 to �21 kJ mol�1) and are likely to dominate the energetics of their templated syntheses

INSIG1 influences obesity-related hypertriglyceridemia in humans

In our analysis of a quantitative trait locus (QTL) for plasma triglyceride (TG) levels [logarithm of odds (LOD) = 3.7] on human chromosome 7q36, we examined 29 single nucleotide polymorphisms (SNPs) across INSIG1, a biological candidate gene in the region. Insulin-induced genes (INSIGs) are feedback mediators of cholesterol and fatty acid synthesis in animals, but their role in human lipid regulation is unclear. In our cohort, the INSIG1 promoter SNP rs2721 was associated with TG levels (P = 2 × 10−3 in 1,560 individuals of the original linkage cohort, P = 8 × 10−4 in 920 unrelated individuals of the replication cohort, combined P = 9.9 × 10−6). Individuals homozygous for the T allele had 9% higher TG levels and 2-fold lower expression of INSIG1 in surgical liver biopsy samples when compared with individuals homozygous for the G allele. Also, the T allele showed additional binding of nuclear proteins from HepG2 liver cells in gel shift assays. Finally, the variant rs7566605 in INSIG2, the only homolog of INSIG1, enhances the effect of rs2721 (P = 0.00117). The variant rs2721 alone explains 5.4% of the observed linkage in our cohort, suggesting that additional, yet-undiscovered genes and sequence variants in the QTL interval also contribute to alterations in TG levels in humans

Lithologic Control on the Scaling Properties of the First-Order Streams of Drainage Networks: A Monofractal Analysis

The movement of water through the landscape can be investigated at different scales. This study dealt with the interrelation between bedrock lithology and the geometry of the overlying drainage systems. Parameters of fractal analysis, such as fractal dimension and lacunarity, were used to measure and quantify this relationship. The interrelation between bedrock lithology and the geometry of the drainage systems has been widely studied in the last decades. The quantification of this linkage has not yet been clearly established. Several studies have selected river basins or regularly shaped areas as study units, assuming them to be lithologically homogeneous. This study considered irregular distributions of rock types, establishing areas of the soil map (1:25,000) with the same lithologic information as study units. The tectonic stability and the low climatic variability of the study region allowed effective investigation of the lithologic controls on the drainage networks developed on the plutonic rocks, the metamorphic rocks, and the sedimentary materials existing in the study area. To exclude the effect of multiple in- and outflows in the lithologically homogeneous units, we focused this study on the first-order streams of the drainage networks. The geometry of the hydrologic features was quantified through traditional metrics of fluvial geomorphology and scaling parameters of fractal analysis, such as the fractal dimension, the reference density, and the lacunarity. The results demonstrate the scale invariance of both the drainage networks and the set of first-order streams at the study scale and a relationship between scaling in the lithology and the drainage network

An intact light harvesting complex I antenna system is required for complete state transitions in Arabidopsis

M.P.J. acknowledges funding fromthe Leverhulme Trust (U.K.) and the Krebs Institute and 69 Project Sunshine at the University of Sheffield. A.V.R. gratefully acknowledges funding 70 fromthe Biotechnology and Biological Sciences Research Council (U.K.), Leverhulme Trust 71 and The Royal Society Wolfson Research Merit Award. C.N.H. and M.P.J. acknowledge 72 research grant BB/M000265/1 from the Biotechnology and Biological Sciences Research 73 Council (UK). C.N.H. was also supported by an Advanced Award 338895 from the 74 European Research Council. This work was also supported as part of the Photosynthetic 75 Antenna Research Center (PARC), an Energy Frontier Research Center funded by the US 76 Department of Energy, Office of Science, and Office of Basic Energy Sciences under Award 77 Number DE-SC0001035. PARC’s role was to provide partial support for C.N.H

The Localization Transition of the Two-Dimensional Lorentz Model

We investigate the dynamics of a single tracer particle performing Brownian motion in a two-dimensional course of randomly distributed hard obstacles. At a certain critical obstacle density, the motion of the tracer becomes anomalous over many decades in time, which is rationalized in terms of an underlying percolation transition of the void space. In the vicinity of this critical density the dynamics follows the anomalous one up to a crossover time scale where the motion becomes either diffusive or localized. We analyze the scaling behavior of the time-dependent diffusion coefficient D(t) including corrections to scaling. Away from the critical density, D(t) exhibits universal hydrodynamic long-time tails both in the diffusive as well as in the localized phase.Comment: 13 pages, 7 figures

Magnetoluminescence

Pulsar Wind Nebulae, Blazars, Gamma Ray Bursts and Magnetars all contain regions where the electromagnetic energy density greatly exceeds the plasma energy density. These sources exhibit dramatic flaring activity where the electromagnetic energy distributed over large volumes, appears to be converted efficiently into high energy particles and gamma-rays. We call this general process magnetoluminescence. Global requirements on the underlying, extreme particle acceleration processes are described and the likely importance of relativistic beaming in enhancing the observed radiation from a flare is emphasized. Recent research on fluid descriptions of unstable electromagnetic configurations are summarized and progress on the associated kinetic simulations that are needed to account for the acceleration and radiation is discussed. Future observational, simulation and experimental opportunities are briefly summarized.Comment: To appear in "Jets and Winds in Pulsar Wind Nebulae, Gamma-ray Bursts and Blazars: Physics of Extreme Energy Release" of the Space Science Reviews serie

Effects of N-acetyl-cysteine on endothelial function and inflammation in patients with type 2 diabetes mellitus

Endothelial dysfunction has been associated with premature vascular disease. There is increasing data that N-acetyl-cysteine (NAC) may prevent or improve endothelial dysfunction. The aim of this study was to assess the effects of NAC on endothelial function in patients with type 2 diabetes mellitus, a population at high risk for endothelial dysfunction. Twenty-four patients with diabetes mellitus were assigned randomly to initial therapy with either 900 mg NAC or placebo twice daily in a double-blind, cross-over study design. Flowmediated vasodilation (FMD) of the brachial artery was assessed at baseline, after four weeks of therapy, after a four-week wash-out period, and after another four weeks on the opposite treatment. Plasma and red blood cell glutathione levels and high-sensitivity C-reactive protein (CRP) were measured at all four visits. At baseline, FMD was moderately impaired (3.7±2.9%). There was no significant change in FMD after four weeks of NAC therapy as compared to placebo (0.1±3.6% vs. 1.2±4.2%). Similarly, there was no significant change in glutathione levels. However, median CRP decreased from 2.35 to 2.14 mg/L during NAC therapy (p=0.04), while it increased from 2.24 to 2.65 mg/L with placebo. No side effects were noted during the treatment period. In this double-blind, randomized cross-over study, four weeks of oral NAC therapy failed to improve endothelial dysfunction in patients with diabetes mellitus. However, NAC therapy decreased CRP levels, suggesting that this compound may have some efficacy in reducing systemic inflammation