Efficient Modular Synthesis of Isomeric Mono‐ and Bispyridyl[2.2]paracyclophanes by Palladium‐Catalyzed Cross‐ Coupling Reactions

Pyridyl‐substituted [2.2]paracyclophanes build a multifunctional structural motif that is useful in material chemistry, catalysis and for luminescent structures. Nonetheless, there is still a lack of general methods for the synthesis of these structures tolerating easily accessible bromides as well as different isomeric pyridyl groups. Hence the coupling of functionalized [2.2]paracyclophanes with various substituted and functionalized pyridyl derivatives was achieved using Stille, Suzuki and Kumada coupling conditions. Hereby the Stille coupling of a [2.2]paracyclophane is presented as a versatile reaction for the formation of heteromeric [2.2]paracyclophane‐containing biaryl structures.

     

Effect of acid deposition on quantity and quality of dissolved organic matter in soil-water

The aim of this study was to explore how acid deposition may affect the concentration and quality of dissolved organic matter (DOM) in soil-water. This was done by a small-scale acidification experiment during two years where 0.5 × 0.5 m(2) plots were artificially irrigated with water with different sulfuric acid content, and soil-water was sampled using zero-tension lysimeters under the O-horizon. The DOM was characterized using absorbance, fluorescence, and size exclusion chromatography analyses. Our results showed lower mobility of DOM in the high acid treatment. At the same time, there was a significant change in the DOM quality. Soil-water in the high acid treatment exhibited DOM that was less colored, less hydrophobic, less aromatic, and of lower molecular weight, compared to the low acid treatment. This supports the hypothesis that reduction in sulfur deposition is an important driver behind the ongoing brownification of surface waters in many regions.     

Effects of sea surface temperature accuracy on offshore wind resource assessment using a mesoscale model

Offshore wind simulations were performed with the Weather Research and Forecasting (WRF) model driven by three different sea surface temperature (SST) datasets for Japanese coastal waters to investigate the effect of the SST accuracies on offshore wind simulations. First, the National Centers for Environmental Prediction Final analysis (FNL) (1° × 1° grid resolution) and the Operational Sea Surface Temperature and Sea Ice Analysis (OSTIA) (0.05° × 0.05° grid resolution) datasets were compared with in situ measurements. The results show a decrease in accuracy of these datasets toward the coast from the open ocean. Aiming at an improved accuracy of SST data, we developed a new high‐resolution SST dataset (0.02° × 0.02° grid resolution). The new dataset referred to as MOSST is based on the Moderate Resolution Imaging Spectroradiometer (MODIS) product, provided by the Japan Aerospace Exploration Agency (JAXA). MOSST was confirmed to be more accurate than FNL and OSTIA for the coastal waters. Then, WRF simulations were carried out for 1 year with a 2 km grid resolution and by using the FNL, OSTIA and MOSST datasets. The use of the OSTIA dataset for a WRF simulation was found to improve the accuracy when compared with the FNL dataset, and further improvement was obtained when the MOSST dataset was applied. The sensitivity of wind speed and wind energy density to SST is also discussed. We conclude that the use of an accurate SST is a key factor not only for realistic offshore wind simulations near the surface but also for accurate wind resource assessments at the hub height of wind turbines. Copyright © 2014 John Wiley & Sons, Ltd.     

A relative energy failure is associated with low-Mg2+ but not with 4-aminopyridine induced seizure-like events in entorhinal cortex

Interactions of the primary quinone acceptor QA of photosystem II (PS II) with surrounding amino acid residues were studied by analysis of FTIR difference spectra of QA upon its photoreduction (QA-/QA). Structural coupling with a His side chain was revealed by identifying the imidazole bands in the QA-/QA spectrum using the PS II core complexes from Synechocystis PCC 6803 in which both of the two imodazole nitrogens of His side chains were specifically labeled with 15N. Strong hydrogen bonding of the imidazole NH was shown by (i) the presence of several peaks at 2600-3000 cm-1, which arise from Fermi resonance of harmonics or combinations of imidazole ring modes with the hydrogen bonding NH stretching vibration, and (ii) the 1179 cm-1 band, which can be assigned to the mode including NH deformation, is at a frequency significantly higher than the corresponding 1151 cm-1 band of model compounds 4- and 5-methylimidazole in aqueous solution. Also, the presence of the bands specific to the Npi-protonated state at 1109/1102/1090 and 1359 cm-1 suggests that the QA-coupled His is protonated at the Npi site. These results are in good agreement with the model of QA interaction in which His215 (D2), which coordinates to the non-heme iron at Ntau, is hydrogen bonded to the QA carbonyl through the Npi-H bond. In contrast, no bands of Trp side chains were detected in the QA-/QA spectrum upon labeling of the indole ring of Trp residues with indole-d5. This result indicates that Trp254 (D2), which corresponds to Trp252 (M) of the bacterial reaction center that is located in van der Waals contact with QA, is not strongly coupled with QA in PS II. Probably, the predicted pi-pi interaction is not strong enough to influence the vibrations of the indole ring of Trp upon QA reduction, or Trp254 (D2) is located rather far from QA in PS II.     

Untersuchungen zur heterogenen Kondensation von Wasserdampf in Membrankontaktoren

Heterogeneous condensation can contribute to improve the separation efficiency of airborne particles. Submicron particles can be separated due to inertial impaction when particle mass is previously enlarged sufficiently by water vapor condensation. This paper presents a novel, membrane‐based process for creating the requisite supersaturation for condensation. The increase of the particle size based on vapor condensation is detected by a new inline measuring technique.     

Non-invasive continuous glucose monitoring in Type I diabetic patients with optical glucose sensors. Non-Invasive Task Force (NITF)

Glucose intolerance is influenced by body fat mass, as well as muscle fiber composition. To examine the relation between the metabolic profile and muscle morphology in this condition, we performed muscle biopsies and hyperglycemic clamps to determine insulin secretion and clearance, and the insulin effects on glucose disposal and nonesterified fatty acids (NEFA) in 45 glucose intolerant persons (body mass index [BMI], 27.8 +/- 3.0 kg/m2) and 45 normoglycemic controls (BMI, 25.8 +/- 2.7 kg/m2) (P = .001). After adjustment for BMI, glucose-intolerant subjects had lower first-phase insulin release (726 v 954 pmol/L, P = .04). Glucose-intolerant subjects and controls differed in fasting insulin, insulin clearance, and insulin sensitivity to glucose disposal before, but not after, standardizing for BMI. During the clamp, glucose-intolerant subjects had less NEFA suppression and elevated levels of NEFA compared with controls (85% +/- 9% v 90% +/- 6%, P = .02; and 70 +/- 42 micromol/L v 45 +/- 28 micromol/L, P = .01). Glucose-intolerant subjects also had a higher percentage of insulin-insensitive, type 2b muscle fibers, which are not adapted for fat oxidation (7% +/- 9% v 9% +/- 9%, P = .003). BMI was not associated with NEFA suppression or the percentage of type 2b muscle fibers in either group. In conclusion, glucose-intolerant persons have impaired first-phase insulin release, an elevated percentage of type 2b muscle fibers, and increased NEFA availability. Reduced insulin clearance, hyperinsulinemia, and insulin resistance were associated with small increments in BMI.     

Effects of barium on stimulus-induced rises in [K+]o in juvenile rat hippocampal area CA1

Immature glia may not be able to buffer K+ ions released during neuronal activity. Therefore, we investigated entorhinal-hippocampal slices of juvenile rats (ages P15-18 and P22-26) using a perfusion medium containing 2 mM BaCl2 in order to block glial inward rectifying and leak potassium channels. In contrast to adult animals, rises in [K+]o in slices from juvenile animals elicited by repetitive alvear stimulation were not augmented by Ba2+. Ba2+ effects on fast field potentials, slow field potentials and the applied current sink source distribution were roughly similar as in adult rats. We conclude that the capacity to buffer large quantities of K+ ions by mechanisms involving Ba2+-sensitive K+ channels has not yet developed in juveniles.     

Structure of adrenodoxin and function in mitochondrial steroid hydroxylation

The three-dimensional structure of a truncated mutant of bovine adrenodoxin has been resolved at 1.85 A resolution by MAD. The protein consists of a large core region and a more flexible hairpin loop bearing residues which have been previously described as being involved in redox partner recognition. To study the role of distinct protein domains and amino acids of adrenodoxin in interaction with adrenodoxin reductase (AdR), CYP11A1 and CYP11B1, as well as in electron transfer, mutants of adrenodoxin have been prepared by site-directed mutagenesis and produced in Escherichia coli, and their structural and functional properties have been characterized in detail. It could be demonstrated that Tyr82 is located at the edge of the flexible interaction loop of adrenodoxin participating in interactions with AdR and P450s. His56, being close to Tyr82, forms a bridge between the core region of adrenodoxin and the interaction loop. Its role in transmitting changes of the cluster region to the interaction site has also been supported by functional studies. Pro108 of adrenodoxin, the only proline residue contained in the protein and being conserved in this position among several other vertebrate-type ferredoxins, has been demonstrated to be of importance for the correct folding of this protein.     

alpha-Conotoxin ImI exhibits subtype-specific nicotinic acetylcholine receptor blockade: preferential inhibition of homomeric alpha 7 and alpha 9 receptors

Through a study of cloned nicotinic receptors expressed in Xenopus oocytes, we provide evidence that alpha-conotoxin ImI, a peptide marine snail toxin that induces seizures in rodents, selectively blocks subtypes of nicotinic acetylcholine receptors. alpha-Conotoxin ImI blocks homomeric alpha 7 nicotinic receptors with the highest apparent affinity and homomeric alpha 9 receptors with 8-fold lower affinity. This toxin has no effect on receptors composed of alpha 2 beta 2, alpha 3 beta 2, alpha 4 beta 2, alpha 2 beta 4, alpha 3 beta 4, or alpha 4 beta 4 subunit combinations. In contrast to alpha-bungarotoxin, which has high affinity for alpha 7, alpha 9, and alpha 1 beta 1 gamma delta receptors, alpha-conotoxin ImI has low affinity for the muscle nAChR. Related Conus peptides, alpha-conotoxins MI and GI, exhibit a distinct specificity, strictly targeting the muscle subtype receptor but not alpha 7 or alpha 9 receptors. alpha-Conotoxins thus represent selective tools for the study of neuronal nicotinic acetylcholine receptors.