The value of forecasts for PV power plants operating in the past, present and future Scandinavian energy markets

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Möbius and Hückel Cyclacenes with Dewar and Ladenburg Defects

Copyright © 2020 American Chemical Society. Cyclacene nanobelts have not been synthesized in over 60 years and remain one of the last unsynthesized building blocks of carbon nanotubes. Recent work has predicted that Hückel-cyclacenes containing Dewar benzenoid ring isomers are the most stable isomeric forms for several of the smaller sizes of cyclacene belts. Here, we give a more complete picture of the isomers that are possible within these nanobelt systems by simulating embedded Ladenburg (prismane) benzenoid rings in Hückel-[n]cyclacenes (n = 5-14) and embedded Dewar benzenoid rings in twisted Möbius-[n]cyclacenes (n = 9-14). The Möbius-[9]cyclacene isomer containing one Dewar benzenoid defect and the Hückel-[5]cyclacene isomer containing two maximally spaced Ladenburg benzenoid defects are found to be more stable than their conventional Kekulé benzenoid ring counterparts. The isomers that contain Dewar and Ladenburg benzenoid rings have larger electronic singlet-triplet energy gaps and lower polyradical character when compared with the conventional isomers

Association of 11β-hydroxysteroid dehydrogenase type I expression and activity with estrogen receptor β in adipose tissue from postmenopausal women

OBJECTIVE: 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) regenerates active cortisol from inert cortisone in adipose tissue. Elevated adipose tissue 11βHSD1 activity is observed in obese humans and rodents where it is linked to obesity and its metabolic consequences. Menopause is also associated with increased abdominal fat accumulation suggesting that estrogen is also important in adipose tissue metabolism. The purpose of this current study was to establish whether estrogen signalling through estrogen receptors-α and -β (ERα and ERβ) can influence 11βHSD1 in premenopausal and postmenopausal adipose tissue. METHODS: 19 premenopausal (aged 26±5, BMI 23.6±1.6) and 23 postmenopausal healthy women (aged 63±4, BMI 23.4±1.9) were studied. Subcutaneous adipose tissue biopsies and fasting venous blood samples were taken. Body composition was measured by bio-electrical impedance analysis. Human SGBS adipocyte cells were treated with ERα and ERβ-specific agonists for 24h. Basic anthropometric data, Serum 17β-estradiol and progesterone concentrations, ERα and ERβ mRNA levels and 11βHSD1 mRNA, protein and activity levels were assessed. RESULTS: ERβ and 11βHSD1, but not ERα mRNA was significantly increased in adipose tissue from postmenopausal women compared to premenopausal women. ERβ had a significant positive correlation with the mRNA level of 11βHSD1 in adipose tissue from pre- and postmenopausal women. This association between ERβ and 11βHSD1 was greatest in adipose tissue from postmenopausal women. In human SGBS adipocytes, diarylpropiolnitrile (DPN), a selective ERβ agonist increased 11βHSD1 mRNA, protein and activity levels. CONCLUSIONS: We conclude that in adipose tissue, ERβ-mediated estrogen-signalling can upregulate 11βHSD1 and that this may be of particular importance in postmenopausal women

Dewar Benzenoids Discovered in Carbon Nanobelts

© 2020 American Chemical Society. The synthesis of cyclacene nanobelts remains an elusive goal dating back over 60 years. These molecules represent the last unsynthesized building block of carbon nanotubes and may be useful both as seed molecules for the preparation of structurally well-defined carbon nanotubes and for understanding the behavior and formation of zigzag nanotubes more broadly. Here we report the discovery that isomers containing two Dewar benzenoid rings are the preferred form for several sizes of cyclacene. The predicted lower polyradical character and higher singlet-triplet stability that these isomers possess compared with their pure benzenoid counterparts suggest that they may be more stable synthetic targets than the structures that have previously been identified. Our findings should facilitate the exploration of new routes to cyclacene synthesis through Dewar benzene chemistry

Interaction modulation through arrays of clustered methyl-arginine protein modifications

Systematic analysis of human arginine methylation identifies two distinct signaling modes;either isolated modifications akin to canonical post-translational modification regulation, or clustered arrays within disordered protein sequence. Hundreds of proteins contain these methyl-arginine arrays and are more prone to accumulate mutations and more tightly expression-regulated than dispersed methylation targets. Arginines within an array in the highly methylated RNA-binding protein synaptotagmin binding cytoplasmic RNA interacting protein (SYNCRIP) were experimentally shown to function in concert, providing a tunable protein interaction interface. Quantitative immunoprecipitation assays defined two distinct cumulative binding mechanisms operating across 18 proximal arginine-glycine (RG) motifs in SYNCRIP. Functional binding to the methyltransferase PRMT1 was promoted by continual arginine stretches, whereas interaction with the methyl-binding protein SMN1 was arginine content-dependent irrespective of linear position within the unstructured region. This study highlights how highly repetitive modifiable amino acid arrays in low structural complexity regions can provide regulatory platforms, with SYNCRIP as an extreme example how arginine methylation leverages these disordered sequences to mediate cellular interactions

Simulation of Two-Dimensional Infrared Spectroscopy of Peptides Using Localized Normal Modes

Non-linear two-dimensional infrared spectroscopy (2DIR) is most commonly simulated within the framework of the exciton method. The key parameters for these calculations include the frequency of the oscillators within their molecular environments and coupling constants that describe the strength of coupling between the oscillators. It is shown that these quantities can be obtained directly from harmonic frequency calculations by exploiting a procedure that localizes the normal modes. This approach is demonstrated using the amide I modes of polypeptides. For linear and cyclic diamides, and the hexapeptide Z-Aib L-Leu-(Aib)2-Gly- Aib-OtBu, the computed parameters are compared with those from existing schemes, and the resulting 2DIR spectra are consistent with experimental observations. The incorporation of conformational averaging of structures from molecular dynamics simulations is discussed, and a hybrid scheme wherein the Hamiltonian matrix from the quantum chemical local-mode ap- proach is combined with fluctuations from empirical schemes is shown to be consistent with experiment. The work demonstrates that localized vibrational modes can provide a foundation for the calculation of 2DIR spectra that does not rely on extensive parameterization and can be applied to a wide range of systems. For systems that are too large for quantum chemical harmonic frequency calculations, the local mode approach provides a convenient platform for the development of site frequency and coupling maps

Hypophosphatemia after high-dose iron repletion with ferric carboxymaltose and ferric derisomaltose-the randomized controlled HOMe aFers study

Background In patients with iron deficiency anemia, ferric carboxymaltose (FCM) and ferric derisomaltose (FDI) allow high-dose iron repletion. While FCM is reported to induce hypophosphatemia, the frequency of hypophosphatemia after an equivalent dosage of FDI had not been assessed prospectively. Methods In the prospective, single-center, double-blind HOMe aFers study, 26 women with iron deficiency anemia (hemoglobin < 12 g/dL plus either plasma ferritin ≤ 100 ng/mL or a plasma ferritin ≤ 300 ng/mL and transferrin saturation (TSAT) ≤ 30%) were randomized to a single intravenous infusion of 20 mg/kg body weight (up to a maximum of 1000 mg) FCM or FDI. The primary endpoint was the incidence of hypophosphatemia (plasma phosphorus levels < 2.0 mg/dL at day 1, day 7 ± 2, and/or day 35 ± 2 after the infusion). In order to investigate potential skeletal and cardiovascular implications, we assessed changes in other components of mineral and bone metabolism, left ventricular function, and arrhythmias. Results Hypophosphatemia occurred more frequently in women treated with FCM (9 out of 12 [75%]) than in those treated with FDI (1 out of 13 [8%]; p = 0.001). Within 24 h after iron supplementation, women in the FCM group had significant higher plasma intact FGF23 (p < 0.001) and lower plasma 1.25-dihydroxyvitamin D (p < 0.001). As an indicator of urinary phosphorus losses, urinary fractional phosphorus excretion was higher in the FCM group (p = 0.021 at day 7 ± 2 after iron supplementation). We did not observe differences in skeletal and cardiovascular markers, potentially because of the limited number of participants. Conclusions While both FCM and FDI provide efficient iron repletion in participants with iron deficiency anemia, FCM induced hypophosphatemia more often than FDI. Trial registration Clinical Trials.gov NCT02905539. Registered on 8 September 2016. 2015-004808-36 (EudraCT Number) U1111-1176-4563 (WHO Universal Trial Number) DRKS00010766 (Deutsches Register Klinischer Studien

Label-Free Time-Resolved Monitoring of Photolipid Bilayer Isomerization by Plasmonic Sensing

The photo-isomerization of the photolipid azo-PC, a derivative of phosphatidylcholine containing an azobenzene group in its sn2 acyl chain, enables optical control over key properties of supported lipid bilayers (SLBs), such as membrane fluidity and bilayer thickness. However, azobenzenes are well-known for their interaction with various dyes through photo-modulation and -sensitization pathways, presenting a challenge in bilayer characterization by fluorescence microscopy. Label-free tools capable of monitoring the switching process of photolipid SLBs at the nanoscale are therefore highly desired. In this study, the use of dark field scattering spectroscopy on gold nanorods as a highly sensitive approach is demonstrated for analyzing the reversible photo-isomerization dynamics of photolipid SLBs in real time at the single particle level

A Two-Dimensional Polyimide-Graphene Heterostructure with Ultra-fast Interlayer Charge Transfer

Two-dimensional polymers (2DPs) are a class of atomically/molecularly thin crystalline organic 2D materials. They are intriguing candidates for the development of unprecedented organic–inorganic 2D van der Waals heterostructures (vdWHs) with exotic physicochemical properties. In this work, we demonstrate the on-water surface synthesis of large-area (cm2), monolayer 2D polyimide (2DPI) with 3.1-nm lattice. Such 2DPI comprises metal-free porphyrin and perylene units linked by imide bonds. We further achieve a scalable synthesis of 2DPI-graphene (2DPI-G) vdWHs via a face-to-face co-assembly of graphene and 2DPI on the water surface. Remarkably, femtosecond transient absorption spectroscopy reveals an ultra-fast interlayer charge transfer (ca. 60 fs) in the resultant 2DPI-G vdWH upon protonation by acid, which is equivalent to that of the fastest reports among inorganic 2D vdWHs. Such large interlayer electronic coupling is ascribed to the interlayer cation–π interaction between 2DP and graphene. © 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH Gmb