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101.
Dr. Mao Li Dr. Robert Puschmann Andreas Herdlitschka Prof. Dorothea Fiedler Prof. Helma Wennemers 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(36):15716-15719
Inositol hexakisphosphate (InsP6) is a central member of the inositol phosphate messengers in eukaryotic cells. Tools to manipulate the level of InsP6, particularly with compartment selectivity, are needed to enable functional cellular studies. We present cationic octa-(4S)guanidiniumproline ( Z8 ) for the delivery of InsP6 into the cell nucleus. CD spectroscopy, binding affinity, dynamic light scattering, and computational studies revealed that Z8 binds tightly to InsP6 and upon binding undergoes a conformational change from a PPII-helical structure to a structure that forms aggregates. The unique conformational features of the cationic oligoproline enable complex formation and cellular delivery of InsP6 with considerably greater efficacy than the flexible counterpart octaarginine. 相似文献
102.
Rare‐Earth‐Metal Methyl,Amide, and Imide Complexes Supported by a Superbulky Scorpionate Ligand
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Dorothea Schädle Dr. Cäcilia Maichle‐Mössmer Dr. Christoph Schädle Prof. Dr. Reiner Anwander 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(2):662-670
The reaction of monomeric [(TptBu,Me)LuMe2] (TptBu,Me=tris(3‐Me‐5‐tBu‐pyrazolyl)borate) with primary aliphatic amines H2NR (R=tBu, Ad=adamantyl) led to lutetium methyl primary amide complexes [(TptBu,Me)LuMe(NHR)], the solid‐state structures of which were determined by XRD analyses. The mixed methyl/tetramethylaluminate compounds [(TptBu,Me)LnMe({μ2‐Me}AlMe3)] (Ln=Y, Ho) reacted selectively and in high yield with H2NR, according to methane elimination, to afford heterobimetallic complexes: [(TptBu,Me)Ln({μ2‐Me}AlMe2)(μ2‐NR)] (Ln=Y, Ho). X‐ray structure analyses revealed that the monomeric alkylaluminum‐supported imide complexes were isostructural, featuring bridging methyl and imido ligands. Deeper insight into the fluxional behavior in solution was gained by 1H and 13C NMR spectroscopic studies at variable temperatures and 1H–89Y HSQC NMR spectroscopy. Treatment of [(TptBu,Me)LnMe(AlMe4)] with H2NtBu gave dimethyl compounds [(TptBu,Me)LnMe2] as minor side products for the mid‐sized metals yttrium and holmium and in high yield for the smaller lutetium. Preparative‐scale amounts of complexes [(TptBu,Me)LnMe2] (Ln=Y, Ho, Lu) were made accessible through aluminate cleavage of [(TptBu,Me)LnMe(AlMe4)] with N,N,N′,N′‐tetramethylethylenediamine (tmeda). The solid‐state structures of [(TptBu,Me)HoMe(AlMe4)] and [(TptBu,Me)HoMe2] were analyzed by XRD. 相似文献
103.
Synthesis,Reductive Cleavage,and Cellular Interaction Studies of Biodegradable,Polyglycerol Nanogels
Dirk Steinhilber Adam L. Sisson Dorothea Mangoldt Pia Welker Kai Licha Rainer Haag 《Advanced functional materials》2010,20(23):4133-4138
In this paper we describe disulfide containing, polyglycerol nanogels as a new class of biodegradable materials. These nanoparticles are prepared in inverse miniemulsion via an acid catalyzed ring‐opening polyaddition of disulfide containing polyols and polyepoxides. Varying conditions allow us to tune particle size and disulfide content within the polymer network; particles can be prepared with narrow polydispersities and diameters in the range from 25 to 350 nm. Particle degradation under reductive intracellular conditions is studied by various analytical techniques. Gel permeation chromatography indicates that final degradation products have relatively low molecular weights (≤ 5 kDa). In addition, studies in cell culture show these nanoscale materials to be highly biocompatible. Dye‐labelled nanogels are shown by optical microscopy techniques to readily internalize into cells by endocytotic mechanisms. This study highlights the great potential of these particles to function as sophisticated nanotransporters that deliver cargo to a certain tissue or cell target and then biodegrade into smaller fragments which would be cleared from the body by the kidney. (with ≈ 30 kDa molecular weight cut off) 相似文献
104.
Dorothea F. K. Rawn Judy Judge Veronica Roscoe 《Analytical and bioanalytical chemistry》2010,397(6):2525-2531
The application of the quick easy cheap effective rugged and safe (QuEChERS) method has generally been used in the preparation
of produce samples (e.g., lettuce and oranges) for pesticide analysis. In the present study, the QuEChERS method was successfully
applied to the determination of the natural pyrethrins (cinerin I and II, jasmolin I and II, and pyrethrin I and II), as well
as two pyrethroid insecticides, cypermethrin and deltamethrin, in fin and non-fin fish products. Analysis of these compounds
was performed using gas chromatography–mass spectrometry. Although cypermethrin is not and has not been registered for pest
control use in aquaculture operations in Canada, cypermethrin was detected in domestically produced salmon. Cypermethrin was
detected in seven of the 18 Canadian farmed salmon samples (39%), although it was not detected in any wild domestic salmon
(n = 3). Cypermethrin concentrations ranged from 0.3 to 6.5 ng/g in the positive samples. It was not, however, observed in any
imported fish product or any other domestically produced fish product. 相似文献
105.
Ein Chitin‐MOF‐Kompositmaterial mit hierarchischem Porensystem für Anwendungen in der Luftfiltration
106.
Mao Li Robert Puschmann Andreas Herdlitschka Dorothea Fiedler Helma Wennemers 《Angewandte Chemie (International ed. in English)》2020,59(36):15586-15589
Inositol hexakisphosphate (InsP6) is a central member of the inositol phosphate messengers in eukaryotic cells. Tools to manipulate the level of InsP6, particularly with compartment selectivity, are needed to enable functional cellular studies. We present cationic octa‐(4S)guanidiniumproline ( Z8 ) for the delivery of InsP6 into the cell nucleus. CD spectroscopy, binding affinity, dynamic light scattering, and computational studies revealed that Z8 binds tightly to InsP6 and upon binding undergoes a conformational change from a PPII‐helical structure to a structure that forms aggregates. The unique conformational features of the cationic oligoproline enable complex formation and cellular delivery of InsP6 with considerably greater efficacy than the flexible counterpart octaarginine. 相似文献
107.
Bioinspired lubricant‐infused surfaces exhibit various unique properties attributed to their liquid‐like and molecularly smooth nature. Excellent liquid repellency and “slippery” properties, self‐healing, antiicing, anticorrosion characteristics, enhanced heat transfer, antibiofouling, and cell‐repellent properties have been already demonstrated. This progress report highlights some of the recent developments in this rapidly growing area, focusing on properties of lubricant‐infused surfaces, and their emerging applications as well as some future challenges. 相似文献
108.
Planar drawings of clustered graphs are considered. We introduce the notion of completely connected clustered graphs, i.e., hierarchically clustered graphs that have the property that not only every cluster but also each complement of a cluster induces a connected subgraph. As a main result, we prove that a completely connected clustered graph is c-planar if and only if the underlying graph is planar. Further, we investigate the influence of the root of the inclusion tree to the choice of the outer face of the underlying graph and vice versa. 相似文献
109.
Dorothea Heitsch 《Ambix》2016,63(4):285-303
René Descartes (1596–1650) insisted on a heat and light theory to explain cardiac movement, and used concepts such as distillation of the vital spirits, fermentation in the digestive process, and fermentation in the circulation of the blood. I argue that his theory of the body as a heat-exchange system was based on alchemical and natural philosophical notions of fire and light expounded by precursors and contemporaries who included Jean D'Espagnet, Jean Fernel, Jan Baptist van Helmont, and Andreas Libavius. Descartes endeavoured to mechanise their approaches, creating a theory in which fire and heat, a legacy from thermal explanations of physiology, were transformed into alchemical fire, and then into mechanistic or physicalist heat. 相似文献
110.
Biological Chitin–MOF Composites with Hierarchical Pore Systems for Air‐Filtration Applications
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Dorothea Wisser Florian M. Wisser Silvia Raschke Nicole Klein Matthias Leistner Julia Grothe Eike Brunner Stefan Kaskel 《Angewandte Chemie (International ed. in English)》2015,54(43):12588-12591
Metal–organic frameworks (MOFs) are promising materials for gas‐separation and air‐filtration applications. However, for these applications, MOF crystallites need to be incorporated in robust and manageable support materials. We used chitin‐based networks from a marine sponge as a non‐toxic, biodegradable, and low‐weight support material for MOF deposition. The structural properties of the material favor predominant nucleation of the MOF crystallites at the inside of the hollow fibers. This composite has a hierarchical pore system with surface areas up to 800 m2 g−1 and pore volumes of 3.6 cm3 g−1, allowing good transport kinetics and a very high loading of the active material. Ammonia break‐through experiments highlight the accessibility of the MOF crystallites and the adsorption potential of the composite indicating their high potential for filtration applications for toxic industrial gases. 相似文献