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排序方式: 共有352条查询结果,搜索用时 31 毫秒
201.
Mark S. Bannon Aida López Ruiz Karen Corrotea Reyes Miriam Marquez Zahra Wallizadeh Mohammad Savarmand Connor A. LaPres Joerg Lahann Kathleen McEnnis 《Particle & Particle Systems Characterization》2021,38(6):2100016
A successful drug delivery system must overcome complex biological barriers. For particles injected into the blood, one of the first and most critical barriers pertains to blood stability to circulate through the human body. To effectively design drug delivery vehicles, interactions between the particles and blood, as well as the aggregation behavior, must be understood. This work presents a method to analyze particle size and aggregation in blood plasma using a commercially available nanoparticle tracking analysis (NTA) system. As a model system, fluorescently labeled polystyrene nanoparticles are incubated in goat blood plasma and analyzed using NTA. The particles incubated in plasma are found to have a protein corona that is larger than what has been observed by dynamic light scattering (DLS) in diluted plasma. Particles that are decorated with a PEG layer are also found to have large protein coronas in undiluted plasma. Because NTA is based on a unique visualization method, large multicomponent aggregates could be observed and quantified in a manner not feasible with other techniques. PEGylation of the particles is found to decrease the multicomponent aggregation from 1000 ± 200 particles for unmodified to 200 ± 30 particles for 1K PEGylated per 1 × 105 total particles. 相似文献
202.
Ohne Zusammenfassung 相似文献
203.
H. Behnke 《Mathematische Annalen》1940,117(1):89-97
Ohne Zusammenfassung 相似文献
204.
Till Opatz Joerg Senn‐Bilfinger Clemens Richert 《Angewandte Chemie (International ed. in English)》2020,59(24):9236-9240
The SARS‐CoV‐2 outbreak causing the respiratory disease COVID‐19 has left many chemists in academia without an obvious option to contribute to fighting the pandemic. Some of our recent experiences indicate that there are ways to overcome this dilemma. A three‐pronged approach is proposed. 相似文献
205.
In this contribution, the derivation of the energy dissipation rate in generalized visco-elastic material models with internal stress-type variables and linear evolution equations is outlined. The approximated dissipation rate is computed from a positive quadratic form of the nonlinear non-equilibrium stresses and the inverse of the consistent material tangent tensor. The presented method is used to compute the energy dissipation of visco-elastic rubber material in a large scale application of a steady state rolling tire structure. (© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
206.
Benjamin Heuwers Dominik Quitmann Robin Hoeher Frauke M. Reinders Sebastian Tiemeyer Christian Sternemann Metin Tolan Frank Katzenberg Joerg C. Tiller 《Macromolecular rapid communications》2013,34(2):180-184
In contrast to all known shape memory polymers, the melting temperature of crystals in shape memory natural rubber (SMNR) can be greatly manipulated by the application of external mechanical stress. As shown previously, stress perpendicular to the prior programming direction decreases the melting temperature by up to 40 K. In this study, we investigated the influence of mechanical stress parallel to prior stretching direction during programming on the stability of the elongation‐stabilizing crystals. It was found that parallel stress stabilizes the crystals, which is indicated by linear increase of the trigger temperature by up to 17 K. The crystal melting temperature can be increased up to 126.5 °C under constrained conditions as shown by X‐ray diffraction measurements. 相似文献
207.
García-Alonso J Fakhrullin RF Paunov VN Shen Z Hardege JD Pamme N Haswell SJ Greenway GM 《Analytical and bioanalytical chemistry》2011,400(4):1009-1013
There is an increasing demand for easy and cost-effective methods to screen the toxicological impact of the growing number
of chemical mixtures being generated by industry. Such a screening method has been developed using viable, genetically modified
green fluorescent protein (GFP) reporter yeast that was magnetically functionalised and held within a microfluidic device.
The GFP reporter yeast was used to detect genotoxicity by monitoring the exposure of the cells to a well-known genotoxic chemical
(methyl methane sulfonate, MMS). The cells were magnetised using biocompatible positively charged PAH-stabilised magnetic
nanoparticles with diameters around 15 nm. Gradient mixing was utilised to simultaneously expose yeast to a range of concentrations
of toxins, and the effective fluorescence emitted from the produced GFP was measured. The magnetically enhanced retention
of the yeast cells, with their facile subsequent removal and reloading, allowed for very convenient and rapid toxicity screening
of a wide range of chemicals. This is the first report showing magnetic yeast within microfluidic devices in a simple bioassay,
with potential applications to other types of fluorescent reporter yeast in toxicological and biomedical research. The microfluidic
chip offers a simple and low-cost screening test that can be automated to allow multiple uses (adapted to different cell types)
of the device on a wide range of chemicals and concentrations. 相似文献
208.
Andreini M Doknic D Sutkeviciute I Reina JJ Duan J Chabrol E Thepaut M Moroni E Doro F Belvisi L Weiser J Rojo J Fieschi F Bernardi A 《Organic & biomolecular chemistry》2011,9(16):5778-5786
DC-SIGN and Langerin are two C-type lectins involved in the initial steps of HIV infections: the former acts as a viral attachment factor and facilitates viral invasion of the immune system, the latter has a protective effect. Potential antiviral compounds targeted against DC-SIGN were synthesized using a common fucosylamide anchor. Their DC-SIGN affinity was tested by SPR and found to be similar to that of the natural ligand Lewis-X (Le(X)). The compounds were also found to be selective for DC-SIGN and to interact only weakly with Langerin. These molecules are potentially useful therapeutic tools against sexually transmitted HIV infection. 相似文献
209.
210.
Dr. Verena Resch Horst Lechner Dr. Joerg H. Schrittwieser Dr. Silvia Wallner Prof. Dr. Karl Gruber Prof. Dr. Peter Macheroux Prof. Dr. Wolfgang Kroutil 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(41):13173-13179
Fluorine is commonly applied in pharmaceuticals to block the degradation of bioactive compounds at a specific site of the molecule. Blocking of the reaction center of the enzyme‐catalyzed ring closure of 1,2,3,4‐tetrahydrobenzylisoquinolines by a fluoro moiety allowed redirecting the berberine bridge enzyme (BBE)‐catalyzed transformation of these compounds to give the formation of an alternative regioisomeric product namely 11‐hydroxy‐functionalized tetrahydroprotoberberines instead of the commonly formed 9‐hydroxy‐functionalized products. Alternative strategies to change the regioselectivity of the enzyme, such as protein engineering, were not applicable in this special case due to missing substrate–enzyme interactions. Medium engineering, as another possible strategy, had clear influence on the regioselectivity of the reaction pathway, but did not lead to perfect selectivity. Thus, only substrate tuning by introducing a fluoro moiety at one potential reactive carbon center switched the reaction to the formation of exclusively one regioisomer with perfect enantioselectivity. 相似文献