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171.
In this contribution, the LuGre model is extended and the effect of frictional aging is incorporated using the state variable approach. The adapted friction model is used in combination with a single-degree-of-freedom oscillator to investigate the basic effects on the stick-slip amplitude and period. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
172.
173.
Kristina?Zubow Anatolij?Zubow Viktor?Anatolievich?ZubowEmail author 《Journal of Cluster Science》2011,22(4):603-619
It was investigated how the “wall effect” influences the cluster distribution in water and 3.5 wt.% NaCl solution being in
a glass cylinder. The cluster distribution in a mass assemble up to 2.2 million Dalton was determined in dependence on the
distance to the wall at normal atmospheric pressure. The average cluster mass, the rate of collapsed and skeletal clusters
and the number of cluster kinds depended on the distance to the wall and on stirring methods. In different liquid’s layers
and at different distances to the wall, there were registered newly appearing clusters as well as disappearing ones especially,
solvated clusters of ion pairs (SCIPs). Under non-stirring conditions, the base water cluster (H2O)12 and (NaCl·40H2O)2 are the most sensitive to the wall distance. Other SCIPs like dimers, tetramers and hexamers remain stable at stirring in
the vessel center (12 rad/s) and don’t react to wall approaching however at cylinder rotation (8.9 rad/s) these SCIPs are
sensitive to the wall. The wall nature, the distance to the wall and the constant magnetic field were concluded to influence
the cluster distribution differently. Cluster properties were assumed to be applied by sea water living organisms for their
navigation. 相似文献
174.
Iaroshenko VO Bunescu A Spannenberg A Supe L Milyutina M Langer P 《Organic & biomolecular chemistry》2011,9(21):7554-7558
The reaction of 1,3-bis-silyl enol ethers with 3-methoxalylchromones affords a great variety of functionalised 2,4'-dihydroxybenzophenones. These products are formed by a domino Michael/retro-Michael/Mukaiyama-aldol reaction. The synthesized compounds are promising candidates for the synthesis of the novel UV-A/B and UV-B filters. 相似文献
175.
A resin-bound nitroso compound sequestered a single unexpected component from crude plant seed extracts. Several plants, including Piper nigrum, Eugenia caryophyllata, and Pimenta dioica, were extracted with organic solvent in the presence of a nitroso-containing resin. The nitroso resin selectively sequestered a single compound, β-caryophyllene, via a chemo- and regioselective ene reaction. The ene product was released from the resin, and proper selection of the solid-phase linker and cleavage cocktail allowed concomitant further transformation of the primary ene product to a novel functionalized polycycle. Preliminary studies indicate that the new hydroxylamine-containing natural product derivatives have antibiotic activity. 相似文献
176.
177.
Methodology and Computing in Applied Probability - 相似文献
178.
Viktor A. Ilin Elena V. Pyzhik Anton B. Balakhonov Maksim A. Kiryushin Evgeniya V. Shcherbatova Andrey A. Kuznetsov Pavel A. Kostin Andrey V. Golovin Vladimir A. Korshun Vladimir A. Brylev Kseniya A. Sapozhnikova Alexey M. Kopylov Galina V. Pavlova Igor N. Pronin 《Molecules (Basel, Switzerland)》2023,28(1)
Central nervous system tumors related to gliomas are of neuroectodermal origin and cover about 30% of all primary brain tumors. Glioma is not susceptible to any therapy and surgical attack remains one of the main approaches to its treatment. Preoperative tumor imaging methods, such as positron emission tomography (PET), are currently used to distinguish malignant tissue to increase the accuracy of glioma removal. However, PET is lacking a specific visualization of cells possessing certain molecular markers. Here, we report an application of aptamers to enhancing specificity in imaging tumor cells bearing the epidermal growth factor receptor (EGFR). Glioblastoma is characterized by increased EGFR expression, as well as mutations of this receptor associated with active division, migration, and adhesion of tumor cells. Since 2021, EGFR has been included into the WHO classification of gliomas as a molecular genetic marker. To obtain conjugates of aptamers GR20 and GOL1-specific to EGFR, a 4-[18F]fluorobenzylazide radiotracer was used as a synthon. For the production of the synthon, a method of automatic synthesis on an Eckert & Ziegler research module was adapted and modified using spirocyclic iodonium ylide as a precursor. Conjugation of 4-[18F]fluorobenzylazide and alkyne-modified aptamers was carried out using Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) with/without the TBTA ligand. As a result, it was possible to obtain 18F-labelled conjugates with 97% radiochemical purity for [18F]FB-GR20 and 98% for [18F]FB-GOL1. The obtained conjugates can be used for further studies in PET analysis on model animals with grafted glioblastoma. 相似文献
179.
180.
The mechanism of photolytic degradation of 2-4-6-trinitrotoluene (TNT) by UVA–visible light (>320 nm) in ethanolic, aqueous-ethanolic, and aqueous solutions was investigated by electrospray and aerodynamic thermal breakup droplet ionization mass-spectrometric analyses. For the photolysis, a DRK-120 mercury-quartz lamp was used. Products of the photolysis reaction were compared with known products of TNT transformation in the environment. Because the photochemistry of some compounds in alcohols (in contrast to aqueous solutions) features a transfer of electrons from the solvent to the light-excited compound, we believe that the efficiency of photolysis (polymerization) of TNT in ethanol and aqueous-ethanolic solutions is based on this mechanism. 相似文献