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71.
Friso F. C. Dubach Wouter G. Ellenbroek Cornelis Storm 《Journal of polymer science. Part A, Polymer chemistry》2021,59(12):1188-1199
Mechanophores are molecules that are incorporated into a host material and react to the local mechanical condition—the state of stress or strain—of that host material. Among their many purposes is that of a reporter: Mechanophores whose optical activity changes in response to mechanical cues can reveal bulk material processes that are ordinarily hidden, such as fatigue and fracture. Moreover, they may do so well before a material is fully fractured. To extract quantitative information from the optical signals from embedded mechanophores it is important that the mechanophores, which are generally a minority component of the material, report proportionally and unambiguously on the mechanical condition of the bulk. This is particularly important for early reporting of damage and wear, for which the optical signal from the mechanophore should accurately reflect bulk bond scission. In this article, we develop and analyze a general theory for the quality of optical mechanoreporting by mechanophores in soft materials, based on the Bell-Evans theory of bond breaking. We find, that at the typical low fractions in which mechanophores are incorporated the overall change in strength is limited, but that the proportionality of the reporting can be off by significant amounts, particularly at short times after loading but, for non-scissile bonds, at long times as well. 相似文献
72.
High-performance liquid chromatography coupled with positive-ion electrospray ionisation tandem mass spectrometry was used for the determination and confirmation of 13 sulphonamide drugs in environmental water samples in the low ng/L-range. Enrichment with concentration factors of 130-670 was performed by solid phase extraction, achieving recoveries of 50 to 90%. After gradient elution HPLC, detection and quantification was performed using selected reaction monitoring (SRM) with limits of detection between 0.2 and 3.7 microg/L. Confirmation was obtained by either SRM transitions of collision induced dissociation reactions or daughter ion mass spectra. Primary and secondary effluents of municipal waste water treatment plants and different surface waters were examined. The compounds sulphamethoxazole and sulphadiazine were detected and confirmed with concentrations ranging between 30-2000 ng/L and 10-100 ng/L, respectively. The compound sulphamethizole was detected in low amounts but could not be positively confirmed. 相似文献
73.
Michaela Weiskircher Heike Niemeyer Frank Deters Roland Storm 《Nachrichten aus der Chemie》1996,44(10):1027-1028
74.
Storm Hassell-Hart Sarah Picaud Raphael Lengacher Joshua Csucker Regis Millet Gilles Gasser Roger Alberto Hannah Maple Robert Felix Zbigniew J. Leśnikowski Helen J. S. Stewart Timothy J. Chevassut Simon Morley Panagis Filippakopoulos John Spencer 《Helvetica chimica acta》2021,104(3):e2000214
A series of bulky organometallic and organic analogues of the bromodomain (BRD) inhibitor (+)-JQ1 have been prepared. The most potent, N-[(adamantan-1-yl)methyl]-2-[(9S)-7-(4-chlorophenyl)-4,5,13-trimethyl-3-thia-1,8,11,12-tetraazatricyclo[8.3.0.02,6]trideca-2(6),4,7,10,12-pentaen-9-yl]acetamide, 2e , showed excellent potency with an KD=ca. 130 nm vs. BRD4(1) and a ca. 2-fold selectivity over BRD4(2) (KD=ca. 260 nm ). Its binding to the first bromodomain of BRD4 was determined by a protein cocrystal structure. 相似文献
75.
We explore the “oriented line graph” construction associated with a hypergraph, leading to a construction of pairs of strongly connected directed graphs whose adjacency operators have the same spectra. We give conditions on a hypergraph so that a hypergraph and its dual give rise to isospectral, but non‐isomorphic, directed graphs. The proof of isospectrality comes from an argument centered around hypergraph zeta functions as defined by Storm. To prove non‐isomorphism, we establish a Whitney‐type result by showing that the oriented line graphs are isomorphic if and only if the hypergraphs are. © 2009 Wiley Periodicals, Inc. J Graph Theory 63: 231–242, 2010 相似文献
76.
We consider a model in which dark matter is stable as it is charged under a Z2 symmetry that is residual after an A4 flavour symmetry is broken. We consider the possibility to generate the quark masses by charging the quarks appropriately under A4. We find that it is possible to generate the CKM mixing matrix by an interplay of renormalisable and dimension-six operators. In this set-up, we predict the third neutrino mixing angle to be large and the dark matter relic density to be in the correct range. Low energy observables - in particular meson-antimeson oscillations - are hard to facilitate. We find that only in a situation where there is a strong cancellation between the Standard Model contribution and the contribution of the new Higgs fields, B meson oscillations are under control. 相似文献
77.
Marcos Fernandez-Castano Romera René P. M. Lafleur Dr. Clément Guibert Dr. Ilja K. Voets Dr. Cornelis Storm Prof. Rint P. Sijbesma 《Angewandte Chemie (International ed. in English)》2017,56(30):8771-8775
Biomimetic, strain-stiffening materials are reported, made through self-assembly and covalent fixation of small building blocks to form fibrous hydrogels that are able to stiffen by an order of magnitude in response to applied stress. The gels consist of semi-flexible rodlike micelles of bisurea bolaamphiphiles with oligo(ethylene oxide) (EO) outer blocks and a polydiacetylene (PDA) backbone. The micelles are fibers, composed of 9–10 ribbons. A gelation method based on Cu-catalyzed azide–alkyne cycloaddition (CuAAC), was developed and shown to lead to strain-stiffening hydrogels with unusual, yet universal, linear and nonlinear stress–strain response. Upon gelation, the X-ray scattering profile is unchanged, suggesting that crosslinks are formed at random positions along the fiber contour without fiber bundling. The work expands current knowledge about the design principles and chemistries needed to achieve fully synthetic, biomimetic soft matter with on-demand, targeted mechanical properties. 相似文献
78.
79.
Ohne Zusammenfassung 相似文献
80.
We compared the effectiveness of 1 mM Geritol, 12% corn oil emulsion, Kaolin-pectin, single contrast oral barium sulfate, and effervescent granules as enteric magnetic resonance imaging (MRI) contrast agents. Five volunteers were recruited. Each volunteer ingested for examinations, separated by at least one week, either 500 ml of each of the liquid preparations or two packets of the CO2 granules (producing 400 ml of CO2 per packet). Abdominal MR images were then obtained using a 1.5 T Magnetom imager and SE 550/22, SE 2000/45/90 and FISP 40/18/40 degrees pulse sequences. The oil emulsions were best tolerated. Barium sulfate caused the greatest amount of nausea, followed by Geritol and Kaolin-pectin. With FISP 40/18/40 degrees, 60%-80% of the small bowel was well delineated using oil emulsion, Kaolin-pectin, or barium sulfate. We conclude that oil emulsion was by far the best enteric MR contrast agent in our study. Good delineation of the small bowel and pancreas can be achieved using oil emulsion and gradient echo pulse sequences. The lack of side-effects and the excellent taste make it highly acceptable to human subjects. 相似文献