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971.
The natural linear orderings of an n-dimensional cube over a finite set A are investigated. We obtain a characterization theorem for these orderings extending earlier result, e.g., for natural orderings on finite Boolean lattices, as given in [5.], 193–197. 相似文献
972.
S.J.H.?Petra K.A.H.?van Leeuwen L.?Feenstra W.?Hogervorst W.?VassenEmail author 《Applied physics. B, Lasers and optics》2004,79(3):279-283
With a two-dimensional (2D) optical mask at =1083 nm, nanoscale patterns are created for the first time in an atom lithography process using metastable helium atoms. The internal energy of the atoms is used to locally damage a hydrophobic resist layer, which is removed in a wet etching process. Experiments have been performed with several polarizations for the optical mask, resulting in different intensity patterns, and corresponding nanoscale structures. The results for a linear polarized light field show an array of holes with a diameter of 260 nm, in agreement with a computed pattern. With a circularly polarized light field a line pattern is observed with a spacing of /20.5=766 nm. Simulations taking into account many possible experimental imperfections can not explain this pattern. PACS 32.80.Lg; 39.25.+k; 81.16.Nd 相似文献
973.
Lifetime images of autofluorescence of cultivated endothelial cells were recorded using a novel picosecond laser diode in the near ultraviolet range (375 nm). In contrast to existing picosecond light sources this wavelength permits efficient excitation of the free and protein bound coenzyme NADH with fluorescence lifetimes of 0.4-0.5 ns and 2.0-2.5 ns, respectively. The effective fluorescence lifetime tau(eff) (depending on both lifetimes) was homogenously distributed over the cells with some shortening in the perinuclear region, possibly close to mitochondria. A slight decrease of tau(eff) was observed after inhibition of the mitochondrial respiratory chain, whereas a slight increase was observed after inhibition of the glycolytic pathway, thus indicating variations of the ratio of free and protein bound NADH. Although present applications are still limited by their low pulse energy (< or = 5 pJ), uv picosecond laser diodes have a large potential in high resolution fluorescence microscopy and fluorescence lifetime endoscopy. 相似文献
974.
Ina Michalsky Dr. Viktoria Gensch Christian Walla Dr. Marvin Hoffmann Dr. Frank Rominger Dr. Thomas Oeser Prof. Dr. Petra Tegeder Prof. Dr. Andreas Dreuw Prof. Dr. Milan Kivala 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(34):e202200326
A family of fully bridged triphenylamines with embedded 5- and 7-membered rings is presented. The compounds are potent electron donors capable to undergo donor/acceptor interactions with strong cyano-based acceptors both in the solid state and solution. These interactions were evaluated by IR and UV/vis spectroscopy as well as X-ray crystallography. The vinylene-bridged compound was oxidized to the corresponding 1,2-diketone which readily underwent acid-catalyzed condensation with selected 1,2-phenylenediamines. The resulting π-extended quinoxaline derivatives represent valuable building blocks for the development of functional chromophores upon appropriate functionalization. 相似文献
975.
976.
Monika Bosacka Anna Błońska-Tabero Elżbieta Filipek Jana Luxova Petra Šulcová 《Journal of Thermal Analysis and Calorimetry》2017,130(1):95-101
A new dichromium(III) cobalt(II) diphosphate(V) of the formula CoCr2(P2O7)2 was detected in the Co3Cr4(PO4)6–Cr(PO3)3 system. The new compound was obtained as a result of high-temperature solid-state reactions between CoCO3, Cr2O3 and (NH4)2HPO4 as well as between Cr(PO3)3 and Co3Cr4(PO4)6. CoCr2(P2O7)2 was characterized using XRD, DTA and IR methods. Results demonstrated that CoCr2(P2O7)2 crystallizes in the triclinic system and its unit cell parameters were calculated. Its infrared spectrum was presented. CoCr2(P2O7)2 melts incongruently at 1270±10 °C with a formation of solid α-CrPO4. The compound Co3Cr4(PO4)6, component of the system under study, was obtained for the first time as a pure phase. Its thermal stability was also investigated. Co3Cr4(PO4)6 is stable in air up to 1410 ± 20 °C. 相似文献
977.
Dr. Maria Gil-Moles Sebastian Türck Dr. Uttara Basu Dr. Andrea Pettenuzzo Dr. Saurav Bhattacharya Ananthu Rajan Xiang Ma Rolf Büssing Jessica Wölker Dr. Hilke Burmeister Henrik Hoffmeister Pia Schneeberg Andre Prause Petra Lippmann Josephine Kusi-Nimarko Dr. Storm Hassell-Hart Dr. Andrew McGown Dr. Daniel Guest Dr. Yan Lin Dr. Anna Notaro Dr. Robin Vinck Dr. Johannes Karges Dr. Kevin Cariou Dr. Kun Peng Dr. Xue Qin Dr. Xing Wang Dr. Joanna Skiba Dr. Łukasz Szczupak Prof. Dr. Konrad Kowalski Prof. Dr. Ulrich Schatzschneider Dr. Catherine Hemmert Prof. Dr. Heinz Gornitzka Prof. Dr. Elena R. Milaeva Dr. Alexey A. Nazarov Prof. Dr. Gilles Gasser Prof. Dr. John Spencer Dr. Luca Ronconi Prof. Dr. Ulrich Kortz Prof. Dr. Jindrich Cinatl Prof. Dr. Denisa Bojkova Prof. Dr. Ingo Ott 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(71):17928-17940
The global spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has called for an urgent need for dedicated antiviral therapeutics. Metal complexes are commonly underrepresented in compound libraries that are used for screening in drug discovery campaigns, however, there is growing evidence for their role in medicinal chemistry. Based on previous results, we have selected more than 100 structurally diverse metal complexes for profiling as inhibitors of two relevant SARS-CoV-2 replication mechanisms, namely the interaction of the spike (S) protein with the ACE2 receptor and the papain-like protease PLpro. In addition to many well-established types of mononuclear experimental metallodrugs, the pool of compounds tested was extended to approved metal-based therapeutics such as silver sulfadiazine and thiomersal, as well as polyoxometalates (POMs). Among the mononuclear metal complexes, only a small number of active inhibitors of the S/ACE2 interaction was identified, with titanocene dichloride as the only strong inhibitor. However, among the gold and silver containing complexes many turned out to be very potent inhibitors of PLpro activity. Highly promising activity against both targets was noted for many POMs. Selected complexes were evaluated in antiviral SARS-CoV-2 assays confirming activity for gold complexes with N-heterocyclic carbene (NHC) or dithiocarbamato ligands, a silver NHC complex, titanocene dichloride as well as a POM compound. These studies might provide starting points for the design of metal-based SARS-CoV-2 antiviral agents. 相似文献
978.
Central European Journal of Operations Research - The pressure on the speed of information processing ranks business intelligence technologies among the fastest growing decision support tools. The... 相似文献
979.
The rate of acid-catalyzed hydrolysis of O-ethyl-O-methyl-cellulose (EMC) and O-methoxyethyl-O-methyl-cellulose (MEMC), respectively, has been studied. By a two-step depolymerization procedure and monitoring of all individual substitution patterns, rate constants were determined for glucosyl residues with each particular substitution pattern. Two MCs of DS 1.27 (MC1) and 1.95 (MC2) have been perethylated and permethoxyethylated and submitted to TFA hydrolysis in water/acetone in a heating block at 120 °C. EMC1 has also been hydrolyzed without acetone addition, under microwave irradiation, and after partial mechanical degradation by treatment with a sonotrode. For all hydrolyses, a slow (k-a) and, after about 10% conversion, a faster phase of hydrolysis (k-b) was found. Rate constants k-b were in the range of 2–4 × 10?4 s?1 for all peralkylated celluloses. In contrast to previously studied MC, hydrolysis in water/acetone was faster than in water, indicating the influence of solution state and the macromolecular character. No difference was observed for sonotrode pretreated EMC1, while microwave instead of heating block treatment accelerated hydrolysis by a factor of 30 under the chosen conditions. Selectivity with respect to the substitution patterns, expressed as the standard deviation of the individual rate constants k i (i = position of methyl), was higher in the slow initial phase (23–28%), while ranging between 9 and 18% in the main phase of hydrolysis with lower values for MEMC compared to EMC and, in case of EMC1, for aqueous TFA compared to acetone-containing mixtures. Randomness in hydrolytic cleavage is favored by water as solvent and apparently by microwave heating. 相似文献
980.
We investigate Lie–Trotter product formulae for abstract nonlinear evolution equations with delay. Using results from the theory of nonlinear contraction semigroups in Hilbert spaces, we explain the convergence of the splitting procedure. The order of convergence is also investigated in detail, and some numerical illustrations are presented. 相似文献