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61.
New metallosilicate catalysts were prepared by reacting a silanol capped dendrimer, Si[CH2CH2Si(CH3)2OH]4 with MCp2Cl2 (M = TiIV, MoVI, WVI and VV). The resulting Si[CH2CH2>Si(CH3)2OMCp2Cl]4compounds were incorporated in a silica matrix by the sol–gel method. The catalytic activity of the metallosilicates after calcination revealed excellent activity and selectivity towards epoxidation of alkenes with tert-butylhydroperoxide. Maximum activity was observed with molybdenum-containing materials. Analysis of the catalytic activity revealed that the catalysts were truly heterogeneous. 相似文献
62.
Evangelos Pavlakis Michelle Neumann Thorsten Stiewe 《International journal of molecular sciences》2020,21(24)
Tumor progression to a metastatic and ultimately lethal stage relies on a tumor-supporting microenvironment that is generated by reciprocal communication between tumor and stromal host cells. The tumor–stroma crosstalk is instructed by the genetic alterations of the tumor cells—the most frequent being mutations in the gene Tumor protein p53 (TP53) that are clinically correlated with metastasis, drug resistance and poor patient survival. The crucial mediators of tumor–stroma communication are tumor-derived extracellular vesicles (EVs), in particular exosomes, which operate both locally within the primary tumor and in distant organs, at pre-metastatic niches as the future sites of metastasis. Here, we review how wild-type and mutant p53 proteins control the secretion, size, and especially the RNA and protein cargo of tumor-derived EVs. We highlight how EVs extend the cell-autonomous tumor suppressive activity of wild-type p53 into the tumor microenvironment (TME), and how mutant p53 proteins switch EVs into oncogenic messengers that reprogram tumor–host communication within the entire organism so as to promote metastatic tumor cell dissemination. 相似文献
63.
One Question,Multiple Answers: Biochemical and Biophysical Screening Methods Retrieve Deviating Fragment Hit Lists 下载免费PDF全文
Dr. Johannes Schiebel Nedyalka Radeva Dr. Helene Köster Dr. Alexander Metz Timo Krotzky Dr. Maren Kuhnert Prof. Wibke E. Diederich Prof. Andreas Heine Dr. Lars Neumann Dr. Cedric Atmanene Dominique Roecklin Dr. Valérie Vivat‐Hannah Dr. Jean‐Paul Renaud Dr. Robert Meinecke Dr. Nina Schlinck Dr. Astrid Sitte Franziska Popp Dr. Markus Zeeb Prof. Gerhard Klebe 《ChemMedChem》2015,10(9):1511-1521
Fragment‐based lead discovery is gaining momentum in drug development. Typically, a hierarchical cascade of several screening techniques is consulted to identify fragment hits which are then analyzed by crystallography. Because crystal structures with bound fragments are essential for the subsequent hit‐to‐lead‐to‐drug optimization, the screening process should distinguish reliably between binders and non‐binders. We therefore investigated whether different screening methods would reveal similar collections of putative binders. First we used a biochemical assay to identify fragments that bind to endothiapepsin, a surrogate for disease‐relevant aspartic proteases. In a comprehensive screening approach, we then evaluated our 361‐entry library by using a reporter‐displacement assay, saturation‐transfer difference NMR, native mass spectrometry, thermophoresis, and a thermal shift assay. While the combined results of these screening methods retrieve 10 of the 11 crystal structures originally predicted by the biochemical assay, the mutual overlap of individual hit lists is surprisingly low, highlighting that each technique operates on different biophysical principles and conditions. 相似文献
64.
Jadran Vrabec Martin Bernreuther Hans‐Joachim Bungartz Wei‐Lin Chen Wilfried Cordes Robin Fingerhut Colin W. Glass Jürgen Gmehling René Hamburger Manfred Heilig Matthias Heinen Martin T. Horsch Chieh‐Ming Hsieh Marco Hülsmann Philip Jäger Peter Klein Sandra Knauer Thorsten Köddermann Andreas Köster Kai Langenbach Shiang‐Tai Lin Philipp Neumann Jürgen Rarey Dirk Reith Gábor Rutkai Michael Schappals Martin Schenk Andre Schedemann Mandes Schönherr Steffen Seckler Simon Stephan Katrin Stöbener Nikola Tchipev Amer Wafai Stephan Werth Hans Hasse 《化学,工程师,技术》2018,90(3):295-306
This article outlines advances in molecular modeling and simulation using massively parallel high‐performance computers (HPC). In the SkaSim project, partners from the HPC community collaborated with users from science and industry. The aim was to optimize the prediction of thermodynamic property data in terms of efficiency, quality and reliability using HPC methods. In this context, various topics were dealt with: atomistic simulation of homogeneous gas bubble formation, surface tension of classical fluids and ionic liquids, multicriteria optimization of molecular models, the development of the molecular simulation codes ls1 mardyn and ms2, atomistic simulation of gas separation processes, molecular membrane structure generators, transport resistors and the evaluation of predictive property data models based on specific mixture types. 相似文献
65.
Self‐aggregated nanoparticles of N‐dodecyl,N′‐glycidyl(chitosan) as pH‐responsive drug delivery systems for quercetin 下载免费PDF全文
Rafael de Oliveira Pedro Susana Pereira Francisco M. Goycoolea Carla C. Schmitt Miguel G. Neumann 《应用聚合物科学杂志》2018,135(2)
In this study, pH‐responsive amphiphilic chitosan (CS) nanoparticles were used to encapsulate quercetin (QCT) for sustained release in cancer therapy. The novel CS derivatives were obtained by synthesis with 2,3‐epoxy‐1‐propanol, also known as glycidol, followed by acylation with dodecyl aldehyde. Characterization was performed by spectroscopic, viscosimetric, and size‐determination methods. Critical aggregation concentration, morphology, entrapment efficiency, drug release profile, cytotoxicity, and hemocompatibility studies were also carried out. The average size distribution of the self‐assembling nanoparticles measured by dynamic light scattering ranged from 140 to 300 nm. In vitro QCT release and Korsmeyer–Peppas model indicated that pH had a major role in drug release. Cytotoxicity assessments indicated that the nanoparticles were non‐cytotoxic. 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay further revealed that QCT‐loaded nanoparticles could inhibit MCF‐7 cell growth. In vitro erythrocyte‐induced hemolysis indicated the good hemocompatibility of the nanoparticles. These results suggest that the synthesized copolymers might be potential carriers for hydrophobic drugs in cancer therapy. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45678. 相似文献
66.
Magnetic polystyrene–palygorskite nanocomposite obtained by heterogeneous phase polymerization to apply in the treatment of oily waters 下载免费PDF全文
Antonieta Middea Luciana Spinelli Fernando Gomes de Souza Junior Reiner Neumann Thais Fernandes Fabiano Richard Leite Faulstich Otavio Gomes 《应用聚合物科学杂志》2018,135(15)
Water contaminated by oil poses challenges to the management of water resources. Magnetic nanoparticles has been issue of different potential applications including remotion oil from water. Magnetic polystyrene–palygorskite nanocomposites were prepared by a heterogeneous phase polymerization for the removal of organic contaminants from water. The organo‐Fe3O4‐palygorskite nanoparticles were coated with polystyrene, forming water repellent and oil absorbing surfaces to promote the removal of oil from the surfaces of nanocomposites by applying an external magnetic field. X‐ray fluorescence, X‐ray diffraction, scanning electron microscopy, zeta potential and size distribution measurement, surface area determination by BET, density measurement by He pycnometry, carbon grade determination, thermogravimetric analysis, Fourier‐transform infrared spectroscopy, Raman spectroscopy, and evaluation of hydrophobicity by contact angle were used to characterize the nanoparticles. The magnetic nanocomposite obtained showed excellent hydrophobicity, around 78° contact angle. In addition, oil removal capability tests were also performed, according to which the preliminary results indicated removal of approximately 98% of oil in synthetic oily water samples. The oil–water separation using this magnetic nanocomposite provides a promising alternative strategy for water treatment. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46162. 相似文献
67.
We describe the use of surface plasmon- and surface plasmon fieldenhanced fluorescence spectroscopy for the detection of hybridization reactions between surface-attached probe oligonucleotides and complement strands binding from solution. These targets, exhibiting different base mismatches relative to the probe 15-mer sequences, carry a fluorophore at their 5'-end thus allowing for sensitive detection and quantification of association, kon, and dissociation, koff, rate constants, as well as affinity constants, Ka. We demonstrate that by the competitive binding / replacement of single strand binding proteins the mismatch discrimination can be further enhanced. 相似文献
68.
Polycarbonate films of thickness 30 μm were irradiated with heavy ions by applying a flux of 108 ions cm−2 to produce straight tracks perpendicular to the film surface. The tracks were preferentially etched in 6 M aqueous solution
of sodium hydroxide to prepare cylindrical nanochannels. The channel diameters were tuned between 200 and 600 nm by varying
the etching time. Co81Cu19 alloy nanowires were electrodeposited potentiostatically, while Co/Cu multilayered nanowires, consisting of alternating Co
and Cu layers with thickness 10 nm, were synthesized by means of a pulse plating technique in channels of length 30 μm and
diameter 200 nm. Co81Cu19 alloy nanowires showed an anisotropic magnetoresistance effect of 0.6%, and the giant magnetoresistance of Co/Cu multilayered
nanowires reached up to 8.0%. 相似文献
69.
Alexander M. Khenkin Ronny Neumann Alexander B. Sorokin Alain Tuel 《Catalysis Letters》1999,63(3-4):189-192
The impregnation of H5PV2Mo10O40 polyoxometalate onto MCM‐41 and amino‐modified MCM‐41 materials provided mesoporous active catalysts with large surface areas for aerobic hydrocarbon oxidation using isobutyraldehyde as a reducing agent. The results of the oxidation of alkenes and alkanes gave product selectivities similar to those observed in the corresponding homogeneous reaction although catalytic activity was somewhat reduced. Under appropriate experimental conditions there was no leaching and the solid catalyst could be recovered and reused without loss in activity. This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
70.
An uncommon electrolyte, based on sulphosalicylic acid, was used for nickel-cobalt deposition. Some mechanical properties (internal stress and microhardness) and structural properties of the deposits have been presented. High microhardness (nearly 800 HM) with simultaneous low internal stress (about 50 MPa) can be reached. 相似文献