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11.
Jon E. Carlé Martin Helgesen Natalia K. Zawacka Morten V. Madsen Eva Bundgaard Frederik C. Krebs 《Journal of Polymer Science.Polymer Physics》2014,52(13):893-899
Two low‐band gap polymer series based on benzo[1,2‐b:4,5‐b′]dithiophene (BDT) and dithienylbenzothiadiazole, with different numbers of fluorine substituents on the 2,3,1‐benzothiadiazole unit, have been synthesized and explored in a comparative study of the photochemical stability and operational lifetime in flexible large area roll‐coated bulk heterojunction solar cells. The two polymer series have different side chains on the BDT unit, namely 2‐hexyldecyloxy (BDTHDO) ( P1–P3 ) or 2‐hexyldecylthiophene (BDTTHD) ( P4–P6 ). The photochemical stability clearly shows that the stability enhances along with the number of fluorine atoms incorporated on the polymer backbone. Fabrication of the polymer solar cells based on the materials was carried out in ambient atmosphere on a roll coating/printing machine employing flexible and indium‐tin‐oxide‐free plastic substrates. Solar cells based on the P4–P6 series showed the best performance, reaching efficiencies up to 3.8% for an active area of 1 cm2, due to an enhanced current compared to P1–P3 . Lifetime measurements, carried out according to international summit on OPV stability (ISOS), of encapsulated devices reveals an initial fast decay for P1–P6 in the performance followed by a much slower decay rate, still retaining 40–55% of their initial performance after 250 h of testing under ISOS‐L‐1 conditions. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 893–899 相似文献
12.
Dr. Karin Mannerstedt Dr. Narendra Kumar Mishra Dr. Ebbe Engholm Dr. Morten Lundh Dr. Charlotte S. Madsen Dr. Philip J. Pedersen Dr. Priska Le-Huu Dr. Søren L. Pedersen Dr. Nina Buch-Månson Dr. Björn Borgström Dr. Thomas Brimert Dr. Lisbeth N. Fink Dr. Keld Fosgerau Prof. Niels Vrang Prof. Knud J. Jensen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(9):3166-3176
A glucose responsive insulin (GRI) that responds to changes in blood glucose concentrations has remained an elusive goal. Here we describe the development of glucose cleavable linkers based on hydrazone and thiazolidine structures. We developed linkers with low levels of spontaneous hydrolysis but increased level of hydrolysis with rising concentrations of glucose, which demonstrated their glucose responsiveness in vitro. Lipidated hydrazones and thiazolidines were conjugated to the LysB29 side-chain of HI by pH-controlled acylations providing GRIs with glucose responsiveness confirmed in vitro for thiazolidines. Clamp studies showed increased glucose infusion at hyperglycemic conditions for one GRI indicative of a true glucose response. The glucose responsive cleavable linker in these GRIs allow changes in glucose levels to drive the release of active insulin from a circulating depot. We have demonstrated an unprecedented, chemically responsive linker concept for biopharmaceuticals. 相似文献
13.
Dr. Morten Gotthold Vinum Laura Voigt Colby Bell Dmytro Mihrin Prof. Dr. René Wugt Larsen Prof. Dr. Kensha Marie Clark Prof. Dr. Kasper S. Pedersen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(10):2143-2147
β-Diketonates, such as acetylacetonate, are amongst the most common bidentate ligands towards elements across the entire periodic table and are considered wholly redox-inactive in their complexes. Herein we show that complexation of 1,1,1,5,5,5-hexafluoroacetylacetonate (hfac−) to CrII spontaneously affords CrIII and a reduced β-diketonate radical ligand scaffold, as evidenced by crystallographic analysis, magnetic measurements, optical spectroscopy, reactivity studies, and DFT calculations. The possibility of harnessing β-diketonates as electron reservoirs opens up possibilities for new metal–ligand concerted reactivity in the ubiquitous β-diketonate coordination chemistry. 相似文献
14.
15.
Olena Dobrovolska
yvind Strmland
rjan Sele Handegrd Martin Jakubec Morten L. Govasli ge Aleksander Skjevik Nils ge Frystein Knut Teigen
yvind Halskau 《Molecules (Basel, Switzerland)》2021,26(12)
The driving forces and conformational pathways leading to amphitropic protein-membrane binding and in some cases also to protein misfolding and aggregation is the subject of intensive research. In this study, a chimeric polypeptide, A-Cage-C, derived from α-Lactalbumin is investigated with the aim of elucidating conformational changes promoting interaction with bilayers. From previous studies, it is known that A-Cage-C causes membrane leakages associated with the sporadic formation of amorphous aggregates on solid-supported bilayers. Here we express and purify double-labelled A-Cage-C and prepare partially deuterated bicelles as a membrane mimicking system. We investigate A-Cage-C in the presence and absence of these bicelles at non-binding (pH 7.0) and binding (pH 4.5) conditions. Using in silico analyses, NMR, conformational clustering, and Molecular Dynamics, we provide tentative insights into the conformations of bound and unbound A-Cage-C. The conformation of each state is dynamic and samples a large amount of overlapping conformational space. We identify one of the clusters as likely representing the binding conformation and conclude tentatively that the unfolding around the central W23 segment and its reorientation may be necessary for full intercalation at binding conditions (pH 4.5). We also see evidence for an overall elongation of A-Cage-C in the presence of model bilayers. 相似文献
16.
Reaction kinetics and solubility in water‐organic binary solutions are governed by similar solvation equilibria
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Siim Salmar Morten Vaalma Henry Vider Tiina Tenno Aleksei Kuznetsov Jaak Järv Ants Tuulmets 《Journal of Physical Organic Chemistry》2016,29(3):118-126
The solvation effects observed in water‐organic solutions were studied by combining data for reaction kinetics and dissolution equilibria by means of a linear free‐energy (similarity) analysis. Kinetic data for the pH‐independent hydrolysis of (4‐methoxyphenyl)‐2,2‐dichloroacetate measured in this work and solubility data for naphthalene, and other substrates of low polarity, in aqueous binary mixtures of methanol, ethanol, acetonitrile, dimethyl sulfoxide (DMSO), and 1,4‐dioxane were used. Linear similarity relationships were discovered for these data over the full range of solvent compositions studied. To gain insight into the similarities observed between these different phenomena, molecular dynamics simulations were carried out for naphthalene and an ester in water–acetonitrile solutions. The results revealed considerable preferential solvation of these substrates by the co‐solvent. Linear relationships between the experimental data and the mole fractions of acetonitrile in the solvation shells of substrates were found. Surprisingly, a linear relationship was found between the mole fractions of acetonitrile in the solvation shells of the ester and naphthalene. This linearity indicated that a similar solvation mechanism governs even such different phenomena as dissolution and reaction kinetics. The relationships between the experimental data and the results of the molecular dynamics calculations found in this work explained the solvent effect observed in water‐organic solutions on the molecular level. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
17.
The topology of interbank payment flows 总被引:1,自引:0,他引:1
We explore the network topology of the interbank payments transferred between commercial banks over the Fedwire® Funds Service. We find that the network has both a low average path length and low connectivity. The network includes a tightly connected core of banks to which most other banks connect. The degree distribution is scale free over a substantial range. We find that the properties of the network changed considerably in the immediate aftermath of the events of September 11, 2001. 相似文献
18.
Hideyuki Tatsuno Kasper S. Kjr Kristjan Kunnus Tobias C. B. Harlang Cornelia Timm Meiyuan Guo Pavel Chbera Lisa A. Fredin Robert W. Hartsock Marco E. Reinhard Sergey Koroidov Lin Li Amy A. Cordones Olga Gordivska Om Prakash Yizhu Liu Mads G. Laursen Elisa Biasin Frederik B. Hansen Peter Vester Morten Christensen Kristoffer Haldrup Zoltn Nmeth Dorottya Srosin Szemes va Bajnczi Gyrgy Vank Tim B. Van Driel Roberto Alonso‐Mori James M. Glownia Silke Nelson Marcin Sikorski Henrik T. Lemke Dimosthenis Sokaras Sophie E. Canton Asmus O. Dohn Klaus B. Mller Martin M. Nielsen Kelly J. Gaffney Kenneth Wrnmark Villy Sundstrm Petter Persson Jens Uhlig 《Angewandte Chemie (International ed. in English)》2020,59(1):364-372
Iron N‐heterocyclic carbene (NHC) complexes have received a great deal of attention recently because of their growing potential as light sensitizers or photocatalysts. We present a sub‐ps X‐ray spectroscopy study of an FeIINHC complex that identifies and quantifies the states involved in the deactivation cascade after light absorption. Excited molecules relax back to the ground state along two pathways: After population of a hot 3MLCT state, from the initially excited 1MLCT state, 30 % of the molecules undergo ultrafast (150 fs) relaxation to the 3MC state, in competition with vibrational relaxation and cooling to the relaxed 3MLCT state. The relaxed 3MLCT state then decays much more slowly (7.6 ps) to the 3MC state. The 3MC state is rapidly (2.2 ps) deactivated to the ground state. The 5MC state is not involved in the deactivation pathway. The ultrafast partial deactivation of the 3MLCT state constitutes a loss channel from the point of view of photochemical efficiency and highlights the necessity to screen transition‐metal complexes for similar ultrafast decays to optimize photochemical performance. 相似文献
19.
Reka Geczy Niels Johan Christensen Kim K. Rasmussen Ildik Klomista Manish K. Tiwari Pratik Shah Seong Wook Yang Morten J. Bjerrum Peter W. Thulstrup 《Angewandte Chemie (International ed. in English)》2020,59(37):16091-16097
Fluorescent, DNA‐stabilized silver nanoclusters (DNA‐AgNCs) are applied in a range of applications within nanoscience and nanotechnology. However, their diverse optical properties, mechanism of formation, and aspects of their composition remain unexplored, making the rational design of nanocluster probes challenging. Herein, a synthetic procedure is described for obtaining a high yield of emissive DNA‐AgNCs with a C‐loop hairpin DNA sequence, with subsequent purification by size‐exclusion chromatography (SEC). Through a combination of optical spectroscopy, gel electrophoresis, inductively coupled plasma mass spectrometry (ICP‐MS), and small‐angle X‐ray scattering (SAXS) in conjunction with the systematic study of various DNA sequences, the low‐resolution structure and mechanism of the formation of AgNCs were investigated. Data indicate that fluorescent DNA‐AgNCs self‐assemble by a head‐to‐head binding of two DNA hairpins, bridged by a silver nanocluster, resulting in the modelling of a dimeric structure harboring an Ag12 cluster. 相似文献
20.
In the development of therapeutic proteins, analytical assessment of structural stability and integrity constitutes an important activity, as protein stability and integrity influence drug efficacy, and ultimately patient safety. Existing analytical methodologies solely rely on relative changes in optical properties such as fluorescence or scattering upon thermal or chemical perturbation. Here, we present an absolute analytical method for assessing protein stability, structure, and unfolding utilizing Taylor dispersion analysis (TDA) and LED-UV fluorescence detection. The developed TDA method measures the change in size (hydrodynamic radius) and intrinsic fluorescence of a protein during in-line denaturation with guanidinium hydrochloride (GuHCl). The conformational stability of the therapeutic antibody adalimumab and human serum albumin were characterized as a function of pH. The simple workflow and low sample consumption (40 ng protein per data point) of the methodology make it ideal for assessing protein characteristics related to stability in early drug development or when having a scarce amount of sample available. 相似文献