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621.
622.
Andreas Tiehm Silke Kra?nitzer Yuri Koltypin Aharon Gedanken 《Ultrasonics sonochemistry》2009,16(5):617-621
Zerovalent iron (ZVI) has been demonstrated to be suitable for the dehalogenation of environmental pollutants such as chloroethenes. The construction of ZVI reactive barriers by conventional engineering measures is expensive and limited to shallow aquifers. The use of nanosized ZVI particles opens new opportunities to construct ZVI barriers with less invasive techniques. However, nanosized particles of pure ZVI are pyrophoric and react spontaneously with atmospheric oxygen.In this study, nanosized air-stable ZVI particles were produced by applying ultrasound to a solution of Fe(CO)5 in edible oil. The resulting iron nanoparticles were dispersed in a carbon matrix, and coated with a non-crystalline carbon layer of approx. 2.5 nm. Although, these nanoparticles are non-pyrophoric and stable in air, dechlorination of tetrachloroethene was demonstrated in synthetic aqueous medium and in polluted groundwater. Additionally, hydrogen was formed. Due to the larger surface area, significantly higher mass-normalized reaction rates of the novel carbon-coated nanoparticles were obtained as compared to conventional bulk ZVI material. Surface normalized pseudo-first-order-reaction rates of kSA = 3.49 × 10?3 L h?1 m?2 and 2.33 × 10?2 L h?1 m?2 were calculated for the nano-ZVI and the bulk ZVI, respectively. Dechlorination reaction products of the novel nano-ZVI were trichloroethene, cis-dichloroethene, vinyl chloride, ethene, and ethane. 相似文献
623.
H. Behrens 《Fresenius' Journal of Analytical Chemistry》1891,30(1):125-174
Ohne Zusammenfassung 相似文献
624.
Javier Ceballos Melanie Schwalfenberg George Karageorgis Elena S. Reckzeh Sonja Sievers Claude Ostermann Axel Pahl Magnus Sellstedt Jessica Nowacki Marjorie A. Carnero Corrales Julian Wilke Luca Laraia Kirsten Tschapalda Malte Metz Dominik A. Sehr Silke Brand Konstanze Winklhofer Petra Janning Slava Ziegler Herbert Waldmann 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(47):17172-17181
Bioactive compound design based on natural product (NP) structure may be limited because of partial coverage of NP‐like chemical space and biological target space. These limitations can be overcome by combining NP‐centered strategies with fragment‐based compound design through combination of NP‐derived fragments to afford structurally unprecedented “pseudo‐natural products” (pseudo‐NPs). The design, synthesis, and biological evaluation of a collection of indomorphan pseudo‐NPs that combine biosynthetically unrelated indole‐ and morphan‐alkaloid fragments are described. Indomorphane derivative Glupin was identified as a potent inhibitor of glucose uptake by selectively targeting and upregulating glucose transporters GLUT‐1 and GLUT‐3. Glupin suppresses glycolysis, reduces the levels of glucose‐derived metabolites, and attenuates the growth of various cancer cell lines. Our findings underscore the importance of dual GLUT‐1 and GLUT‐3 inhibition to efficiently suppress tumor cell growth and the cellular rescue mechanism, which counteracts glucose scarcity. 相似文献
625.
Dr. Suvendu Sekhar Mondal Alex Kreuzer Dr. Karsten Behrens Prof. Dr. Gisela Schütz Prof. Hans-Jürgen Holdt Dr. Michael Hirscher 《Chemphyschem》2019,20(10):1311-1315
Quantum sieving of hydrogen isotopes is experimentally studied in isostructural hexagonal metal-organic frameworks having 1-D channels, named IFP-1, −3, −4 and −7. Inside the channels, different molecules or atoms restrict the channel diameter periodically with apertures larger (4.2 Å for IFP-1, 3.1 Å for IFP-3) and smaller (2.1 Å for IFP-7, 1.7 Å for IFP-4) than the kinetic diameter of hydrogen isotopes. From a geometrical point of view, no gas should penetrate into IFP-7 and IFP-4, but due to the thermally induced flexibility, so-called gate-opening effect of the apertures, penetration becomes possible with increasing temperature. Thermal desorption spectroscopy (TDS) measurements with pure H2 or D2 have been applied to study isotope adsorption. Further TDS experiments after exposure to an equimolar H2/D2 mixture allow to determine directly the selectivity of isotope separation by quantum sieving. IFP-7 shows a very low selectivity not higher than S=2. The selectivity of the materials with the smallest pore aperture IFP-4 has a constant value of S≈2 for different exposure times and pressures, which can be explained by the 1-D channel structure. Due to the relatively small cavities between the apertures of IFP-4 and IFP-7, molecules in the channels cannot pass each other, which leads to a single-file filling. Therefore, no time dependence is observed, since the quantum sieving effect occurs only at the outermost pore aperture, resulting in a low separation selectivity. 相似文献
626.
Ernst-August Behrens 《Mathematische Annalen》1954,127(1):441-452
Ohne Zusammenfassung 相似文献
627.
Silke W.W. Rolles 《Probability Theory and Related Fields》2006,135(2):216-264
Let G be a finite tree. It is shown that edge-reinforced random walk on ℤ×G with large initial weights is recurrent. This includes recurrence on multi-level ladders of arbitrary width. For edge-reinforced
random walk on {0,1, . . . ,n}×G, it is proved that asymptotically, with high probability, the normalized edge local times decay exponentially in the distance
from the starting level. The estimates are uniform in n. They are used in the recurrence proof. 相似文献
628.
629.
Ernst-August Behrens 《Mathematische Annalen》1956,132(2):95-105
Ohne Zusammenfassung 相似文献
630.
X-Ray diffraction analysis of bis(6,6-dimethylpentafulvene)pentacarbonyldiiron and 6,6-diphenylpentafulvenepentacarbonyldiiron has provided the first detailed information about the bonding in 6,6-disubstituted pentafulvenecarbonyliron complexes. 相似文献