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991.
Sagis LM Ruiter Rd Miranda FJ Ruiter Jd Schroën K Aelst AC Kieft H Boom R Linden Ev 《Langmuir : the ACS journal of surfaces and colloids》2008,24(5):1608-1612
Polymer microcapsules can be used as controlled release systems in drugs or in foods. Using layer-by-layer adsorption of common food proteins and polysaccharides, we produced a new type of microcapsule with tunable strength and permeability. The shell consists of alternating layers of pectin and whey protein fibrils, yielding a fiber-reinforced nanocomposite shell. The strength can be tightly controlled by varying the number of layers or the density and length of the fibrils in the protein layers. The mechanical stability of these microcapsules appears to be superior to that of currently available multilayer capsules. The method involves only standard unit operations and has the potential for scaling up to industrial production volumes. 相似文献
992.
Lüdtke K Jordan R Furr N Garg S Forsythe K Naumann CA 《Langmuir : the ACS journal of surfaces and colloids》2008,24(10):5580-5584
The two-dimensional (2D) center-of-mass diffusion, D, of end-tethered poly(2-methyl-2-oxazoline) (PMOx) lipopolymer chains was studied in a Langmuir monolayer at the air-water interface using wide-field single molecule fluorescence microscopy. In this case, tethering and stabilization of hydrophilic PMOx chains at the air-water interface is accomplished via end-tethering to lipid molecules forming a hydrophobic anchor. To explore the influence of molecular weight, M n, and surface concentration, c s, on lateral mobility, two different PMOx chain lengths of n = 30 and 50 ( n, number of monomer units) were analyzed over a wide range of c s. Using multiparticle tracking analysis of TRITC-labeled PMOx lipopolymers, we found two regimes of lipopolymer lateral mobility. At low c s, D is independent of surface concentration but increases with decreasing n. Here diffusion properties are well described by the Rouse model. In contrast, at more elevated c s, the data do not follow Rouse scaling but are in good agreement with a free area-area model of diffusion. The current study provides for the first time experimental insight into the 2D center-of-mass diffusion of end-tethered polymers at the air-water interface. The obtained results will be of importance for the understanding of diffusion processes in polymer-tethered phospholipid bilayers mimicking biomembranes at low and high tethering concentrations. 相似文献
993.
Microchannel emulsification: from computational fluid dynamics to predictive analytical model 总被引:2,自引:0,他引:2
van Dijke KC Schroën KC Boom RM 《Langmuir : the ACS journal of surfaces and colloids》2008,24(18):10107-10115
Emulsion droplet formation was investigated in terrace-based microchannel systems that generate droplets through spontaneous Laplace pressure driven snap-off. The droplet formation mechanism was investigated through high-speed imaging and computational fluid dynamics (CFD) simulation, and we found good agreement in the overall shape of the phases during droplet formation. An analytical model was derived from the insights that were gained from the CFD simulations, which describes the droplet diameter as a function of applied pressure. The analytical model covers the influence of both process parameters and geometry of the terrace well and can be used for fast optimization and evaluation studies. 相似文献
994.
Dr. Karin Rettenmaier Dr. Gregor A. Zickler Dr. Günther J. Redhammer Dr. Thomas Berger 《Chemphyschem》2023,24(1):e202200586
Mixed transition metal oxides have emerged as promising electrode materials for electrochemical energy storage and conversion. To optimize the functional electrode properties, synthesis approaches allowing for a systematic tailoring of the materials’ composition, crystal structure and morphology are urgently needed. Here we report on the room-temperature electrodeposition of a ternary oxide based on earth-abundant metals, specifically, the defective cubic spinel ZnMnO3. In this unprecedented approach, ZnO surfaces act as (i) electron source for the interfacial reduction of MnO4− in aqueous solution, (ii) as substrate for epitaxial growth of the deposit and (iii) as Zn precursor for the formation of ZnMnO3. Epitaxial growth of ZnMnO3 on the lateral facets of ZnO nanowires assures effective electronic communication between the electroactive material and the conducting scaffold and gives rise to a pronounced 2-dimensional morphology of the electrodeposit forming – after partial delamination from the substrate – twisted nanosheets. The synthesis strategy shows promise for the direct growth of different mixed transition metal oxides as electroactive phase onto conductive substrates and thus for the fabrication of binder-free nanocomposite electrodes. 相似文献
995.
In this paper we study extensions between Cohen–Macaulay modules for algebras arising in the categorifications of Grassmannian cluster algebras. We prove that rank 1 modules are periodic, and we give explicit formulas for the computation of the period based solely on the rim of the rank 1 module in question. We determine \(\mathrm{Ext}^i(L_I, L_J)\) for arbitrary rank 1 modules \(L_I\) and \(L_J\). An explicit combinatorial algorithm is given for the computation of \(\mathrm{Ext}^i(L_I, L_J)\) when i is odd, and when i even, we show that \(\mathrm{Ext}^i(L_I, L_J)\) is cyclic over the centre, and we give an explicit formula for its computation. At the end of the paper we give a vanishing condition of \(\mathrm{Ext}^i(L_I, L_J)\) for any \(i>0\). 相似文献
996.
Thomas Rosenau Antje Potthast Nele Sophie Zwirchmayr Hubert Hettegger Felix Plasser Takashi Hosoya Markus Bacher Karin Krainz Thomas Dietz 《Cellulose (London, England)》2017,24(9):3671-3687
Hexeneuronic acids (HexA) have long been known as triggers for discoloration processes in glucuronoxylan-containing cellulosic pulps. They are formed under the conditions of pulping from 4-O-methylglucuronic acid residues, and are removed in an “A stage” along the bleaching sequences, which mainly comprises acidic washing treatments. The chemical structures of HexA-derived chromophoric compounds 4–8, which make up 90% of the HexA-derived chromophores, are reported here for the first time. The compounds are ladder-type, mixed quinoid-aromatic oligomers of the bis(furano)-[1,4]benzoquinone and bis(benzofurano)-[1,4]benzoquinone type. The same chromophoric compounds are generated independently of the starting material, which can be either a) HexA in pulp, b) the HexA model compound methyl 1-13C-4-deoxy-β-L-threo-hex-4-enopyranosiduronic acid (1) or c) a mixture of the primary degradation intermediates of 1, namely 5-formyl-furancarboxylic acid (2) and 2-furancarboxylic acid (3). Isotopic labeling (13C) in combination with NMR spectroscopy and mass spectrometry served for structure elucidation, and final confirmation was provided by X-ray structure analysis. 13C-Isotopic labeling was also used to establish the formation mechanisms, showing all the compounds to be composed of condensed, but otherwise largely intact, 2-carbonylfuran and 2-carbonylfuran-5-carboxylic acid moieties. These results disprove the frequent assumption that HexA-derived or furfural-derived chromophores are linear furanoid polymers, and might have a direct bearing on structure elucidation studies of “humins”, which are formed as dark-colored byproducts in depolymerization of pentosans and hexosans in different biorefinery scenarios. 相似文献
997.
Dominik Leitz Mathias Hopfinger Karin Stierstorfer Yvonne Morgenstern Joachim Axhausen Andreas Kornath 《无机化学与普通化学杂志》2017,643(19):1202-1207
The preparation of protonated methanesulfonamide was carried out using the superacidic systems HF/AsF5 and HF/SbF5. The vibrational spectroscopic characterization was supported by quantum chemical calculations performed with the PBE1PBE method using the 6‐311G++(3df, 3pd) basis set. A remarkable long nitrogen–sulfur bond length of 1.804(6) Å was observed in a single‐crystal X‐ray structure analysis of [CH3SO2NH3]+[Sb2F11]–. It crystallizes in the orthorhombic space group P21/c with four formula units in the unit cell. Furthermore the crystal structure of CH3SO2NH2 was revisited. 相似文献
998.
Concentration and pattern changes of porcine serum apolipoprotein A‐I in four different infectious diseases
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Anna Marco‐Ramell Karin Hummel Ebrahim Razzazi‐Fazeli Anna Bassols Ingrid Miller 《Electrophoresis》2015,36(4):543-551
Apolipoprotein A‐I (Apo A‐I) is a major protein in lipid/lipoprotein metabolism and decreased serum levels have been observed in many species in response to inflammatory and infectious challenges. Little is known about the porcine homologue, therefore in this work we have characterized it through biochemical and proteomic techniques. In 2DE, porcine serum Apo A‐I is found as three spots, the two more acidic ones corresponding to the mature protein, the more basic spot to the protein precursor. Despite high sequence coverage in LC‐MS/MS, we did not find a sequence or PTM difference between the two mature protein species. Besides this biochemical characterization, we measured overall levels and relative species abundance of serum Apo A‐I in four different viral and bacterial porcine infectious diseases. Lower overall amounts of Apo A‐I were observed in Salmonella typhimurium and Escherichia coli infections. In the 2DE protein pattern, an increase of the protein precursor together with a lower level of mature protein species were detected in the porcine circovirus type 2‐systemic disease and S. typhimurium infection. These results reveal that both the porcine serum Apo A‐I concentration and the species pattern are influenced by the nature of the infectious disease. 相似文献
999.
Zhongdong Sun Dr. Karin Weidner Dr. Naoya Kumagai Prof. Dr. Masakatsu Shibasaki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(49):17574-17577
An α‐N3 7‐azaindoline amide serves as a latent enolate to directly engage in an asymmetric Mannich‐type reaction with N‐thiophosphinoyl imines by the action of a cooperative catalyst. The thus‐obtained highly enantioenriched anti‐adduct was transformed into β‐amino‐α‐azido acid in high yield by simple acidic treatment. 相似文献
1000.
Karin Schmitz 《Nachrichten aus der Chemie》2016,64(7-8):799-807