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31.
Dr. Oscar Francesconi Federico Cicero Prof. Dr. Cristina Nativi Dr. Stefano Roelens 《Chemphyschem》2020,21(3):257-262
The choice between adaptive and preorganized architectures, or of the most effective hydrogen bonding groups to be selected, are dilemmas that supramolecular chemists must address in designing synthetic receptors for such a challenging guest as carbohydrates. In this paper, structurally related architectures featuring two alternative hydrogen bonding motifs were compared to ascertain the structural and functional origin of their binding differences and the advantages that can be expected in monosaccharide recognition. A set of structurally related macrocyclic receptors were prepared, and their binding properties were measured by NMR and ITC techniques in chloroform vs a common saccharidic target, namely, the β-octyl glycoside of D-glucose. Results showed that the diaminocarbazolic motif, recently reported as the constituting unit of highly effective receptors for saccharides in water, is a superior hydrogen bonding motif compared to the previously described diaminopyrrolic motif, which was successfully employed in molecular recognition of carbohydrates in polar organic solvents, due to intrinsic structural and functional factors, rather than to hydrophobic contributions. In addition, the occurrence of a rare example of a thermodynamic template effect exerted by the beta-glucoside has been ascertained, enhancing the synthesis outcome of the otherwise low yielding preparation of the described macrocyclic receptors. 相似文献
32.
It was argued by Schramm and Smirnov that the critical site percolation exploration path on the triangular lattice converges
in distribution to the trace of chordal SLE
6. We provide here a detailed proof, which relies on Smirnov’s theorem that crossing probabilities have a conformally invariant
scaling limit (given by Cardy’s formula). The version of convergence to SLE
6 that we prove suffices for the Smirnov–Werner derivation of certain critical percolation crossing exponents and for our analysis
of the critical percolation full scaling limit as a process of continuum nonsimple loops.
Research of Charles M.Newman was partially supported by the US NSF under grants DMS-01-04278 and DMS-06-06696. 相似文献
33.
District heating plants are becoming more common in European cities. These systems make it possible to furnish users with warm water while locating the production plants in the outskirts having the double benefit of lowering the impact of pollution on the center of the city and achieving better conversion performances. In order to amortize the costs throughout the year, the system often includes a combined heat and power (CHP) plant, to exploit the energy during the summer as well, when the demand for warm water decreases. A linear programming model for the optimal resource management of such a plant is presented and some results for a real case are reported. A distribution network design problem is also addressed and solved by means of mixed integer linear programming. 相似文献
34.
We study the statistical properties of population dynamics evolving in a realistic two-dimensional compressible turbulent velocity field. We show that the interplay between turbulent dynamics and population growth and saturation leads to quasilocalization and a remarkable reduction in the carrying capacity. The statistical properties of the population density are investigated and quantified via multifractal scaling analysis. We also investigate numerically the singular limit of negligibly small growth rates and delocalization of population ridges triggered by uniform advection. 相似文献
35.
BA Reagan KA Wernsing AH Curtis FJ Furch BM Luther D Patel CS Menoni JJ Rocca 《Optics letters》2012,37(17):3624-3626
We demonstrate the operation of a gain-saturated table-top soft x-ray laser at 100?Hz repetition rate. The laser generates an average power of 0.15?mW at λ=18.9 nm, the highest laser power reported to date from a sub-20-nm wavelength compact source. Picosecond laser pulses of 1.5?μJ energy were produced at λ=18.9 nm by amplification in a Mo plasma created by tailoring the temporal intensity profile of single pump pulses with 1?J energy produced by a diode-pumped chirped pulse amplification Yb:YAG laser. Lasing was also obtained in the 13.9?nm line of Ni-like Ag. These results increase by an order of magnitude the repetition rate of plasma-based soft x-ray lasers opening the path to milliwatt average power table-top lasers at sub-20?nm wavelengths. 相似文献
36.
Simone Madama Ermelinda Falletta Amir Mohammad Malvandi Kevin Arzoni Carlo Brogna Marco Varelli Matteo Bertelli Matteo Conti Martina Larini Federico Guidugli Pietro Traldi Simone Cristoni 《Journal of mass spectrometry : JMS》2022,57(8):e4876
In this work, the isolation step in the linear ion trap was performed using different “q values” conditions at a low collision-induced dissociation (CID) energy leading to the parent ion resolution improvements, reasonably due to better ion energy distribution. According to the results, we obtained a greater resolution and mass accuracy operating in both traditional electrospray and low voltage ionization near the q value = 0.778 and with a CID energy of 10%. This effect was evaluated with low-molecular-mass compounds (skatole and arginine). The proposed optimization yielded a superior instrument performance without adding technological complexity to mass spectrometry analyses. 相似文献
37.
A Tailor‐Made Synthetic Polymer for Cell Encapsulation: Design Rationale,Synthesis, Chemical–Physics and Biological Characterizations 下载免费PDF全文
Alessandro Tocchio Federico Martello Camilla Recordati Deepak Kumar Nicholas R. Forsyth Yang Liu Cristina Lenardi 《Macromolecular bioscience》2016,16(6):870-881
This study presents a custom‐made in situ gelling polymeric precursor for cell encapsulation. Composed of poly((2‐hydroxyethyl)methacrylate‐co‐(3‐aminopropyl)methacrylamide) (P(HEMA‐co‐APM) mother backbone and RGD‐mimicking poly(amidoamine) (PAA) moiteis, the comb‐like structured polymeric precursor is tailored to gather the advantages of the two families of synthetic polymers, i.e., the good mechanical integrity of PHEMA‐based polymers and the biocompatibility and biodegradability of PAAs. The role of P(HEMA‐co‐APM) in the regulation of the chemico‐physical properties of P(HEMA‐co‐APM)/PAA hydrogels is thoroughly investigated. On the basis of obtained results, namely the capability of maintaining vital NIH3T3 cell line in vitro for 2 d in a 3D cell culture, the in vivo biocompatibility in murine model for 16 d, and the ability of finely tuning mechanical properties and degradation kinetics, it can be assessed that P(HEMA‐co‐APM)/PAAs offer a cost‐effective valid alternative to the so far studied natural polymer‐based systems for cell encapsulation.
38.
Timo Fuchs Valentín Briega-Martos Jakub Drnec Natalie Stubb Isaac Martens Federico Calle-Vallejo Prof. David A. Harrington Serhiy Cherevko Prof. Olaf M. Magnussen 《Angewandte Chemie (International ed. in English)》2023,62(34):e202304293
The degradation of Pt-containing oxygen reduction catalysts for fuel cell applications is strongly linked to the electrochemical surface oxidation and reduction of Pt. Here, we study the surface restructuring and Pt dissolution mechanisms during oxidation/reduction for the case of Pt(100) in 0.1 M HClO4 by combining operando high-energy surface X-ray diffraction, online mass spectrometry, and density functional theory. Our atomic-scale structural studies reveal that anodic dissolution, detected during oxidation, and cathodic dissolution, observed during the subsequent reduction, are linked to two different oxide phases. Anodic dissolution occurs predominantly during nucleation and growth of the first, stripe-like oxide. Cathodic dissolution is linked to a second, amorphous Pt oxide phase that resembles bulk PtO2 and starts to grow when the coverage of the stripe-like oxide saturates. In addition, we find the amount of surface restructuring after an oxidation/reduction cycle to be potential-independent after the stripe-like oxide has reached its saturation coverage. 相似文献
39.
Mateja
ikovec Mladen Franko Federico G. Cruz Sidney A. Katz 《Analytica chimica acta》1996,330(2-3):245-250
The applicability of thermal lens spectrometry (TLS) for quantification and routine determination of hexavalent chromium was investigated by using a collinear dual beam thermal lens spectrometer. In aqueous solutions the LOD of 0.1 μg l−1 was obtained for Cr(VI) by using 160 mW laser power. The performance of the technique was verified by the determination of hexavalent chromium in standard reference water samples (NIST SRM 1643a and NIST SRM 1643c) and comparing the results for Cr(VI) in CCA (Cr, Cu, As)-treated timber extracts to concentrations obtained by atomic absorption spectrometry (AAS). Good agreement between the TLS results and reported values for Cr(VI) in SRMs as well as AAS results for Cr(VI) in CCA-treated timbers confirmed that TLS is a reliable and accurate analytical technique applicable for the determination of Cr(VI) in aqueous solutions at concentration levels 0.5–100 μg l−1. 相似文献
40.
Pier Luigi Ferrarini Claudio Mori Muwaffag Badawneh Clementina Manera Adriano Martinelli Federico Romagnoli Giuseppe Saccomanni Mauro Miceli 《Journal of heterocyclic chemistry》1997,34(5):1501-1510
Several 1,8-naphthyridine derivatives have been diazotizated to obtain the corresponding hydroxy derivatives or mixture of hydroxy and hydroxy nitro derivatives. The respective amounts of hydroxy and hydroxy nitro derivatives depends on the nature of the substituents, on their position on the naphthyridine nucleus, on the amount of sodium nitrite and on the reaction temperature. A study of the electronic density of some molecules suggests a possible explanation of the effects induced by the nature of the substituents and of their position. Some of the compounds were tested for their ability to inhibit human platelet aggregation in vitro induced by arachidonic acid. Only compound 26 showed interesting antiplatelet activity. 相似文献