607 research outputs found
Tuning the onset voltage of resonant tunneling through InAs quantum dots by growth parameters
We investigated the size dependence of the ground state energy in
self-assembled InAs quantum dots embedded in resonant tunneling diodes.
Individual current steps observed in the current-voltage characteristics are
attributed to resonant single-electron tunneling via the ground state of
individual InAs quantum dots. The onset voltage of the first step observed is
shown to decrease systematically from 200 mV to 0 with increasing InAs
coverage. We relate this to a coverage-dependent size of InAs dots grown on
AlAs. The results are confirmed by atomic force micrographs and
photoluminescence experiments on reference samples.Comment: 3 pages, 3 figure
Confirmatory analysis of ethylglucuronide in urine by liquid-chromatography/electrospray ionization/tandem mass spectrometry according to forensic guidelines
Redox-Rich Metallocene Tetrazene Complexes: Synthesis, Structure, Electrochemistry, and Catalysis
Thermal or photochemical metal-centered cycloaddition reactions of azidocobaltocenium
hexafluoridophosphate or azidoferrocene with (cyclooctadiene)(cyclopentadienyl)cobalt-
(I) afforded the first metallocenyl-substituted tetrazene cyclopentadienyl cobalt complexes together
with azocobaltocenium or azoferrocene as side products. The trimetallic CpCo compounds are
highly conjugated, colored, and redox-active metallo-aromatic compounds, as shown by their
spectroscopic, structural, and electrochemical properties. The CpCo-tetrazenido complex with two
terminally appended cobaltocene units catalyzes electrochemical proton reduction from acetic acid
at a mild overpotential (0.35 V). Replacing cobaltocene with ferrocene moieties rendered the
complex inactive toward catalysis.Austrian Science Fund (FWF), Christian Doppler Association
(Austrian Federal Ministry for Digital and Economic Affairs,
the National Foundation for Research, Technology and
Development), OMV, Marie SkĆodowska-Curie, Deutsche Forschungsgemeinschaf
Creation of Coatings by Temperature-Controlled Polymer Deposition
In this paper, the results of the recent studies on application of lower critical solution temperature (LCST) phenomena of polymer solutions to the surface modification of flat and spherical substrates are reported. It was found that a controlled polymer deposition can be achieved upon prevailing of the LCST, a peculiar surface topology of polymer coating and particles those remarkably effective in stabilizing pigment dispersiions. Second, the finding is that the temperature induces polymer deposition as the coprecipitation of a finely dispersed component on the substrate surface. That goes along with the polymer deposition after exceeding of the LCST which in turn allows for the tailored surface modification of pigments in that particulate additiives can be incorporated into the surface modifying coating
The use of Telenomus remus (Nixon, 1937) (Hymenoptera: Scelionidae) in the management of Spodoptera spp.: potential, challenges and major benefits.
Selenium Utilization by GPX4 Is Required to Prevent Hydroperoxide-Induced Ferroptosis
open24siSelenoproteins are rare proteins among all kingdoms of life containing the 21st amino acid, selenocysteine. Selenocysteine resembles cysteine, differing only by the substitution of selenium for sulfur. Yet the actual advantage of selenolate- versus thiolate-based catalysis has remained enigmatic, as most of the known selenoproteins also exist as cysteine-containing homologs. Here, we demonstrate that selenolate-based catalysis of the essential mammalian selenoprotein GPX4 is unexpectedly dispensable for normal embryogenesis. Yet the survival of a specific type of interneurons emerges to exclusively depend on selenocysteine-containing GPX4, thereby preventing fatal epileptic seizures. Mechanistically, selenocysteine utilization by GPX4 confers exquisite resistance to irreversible overoxidation as cells expressing a cysteine variant are highly sensitive toward peroxide-induced ferroptosis. Remarkably, concomitant deletion of all selenoproteins in Gpx4cys/cys cells revealed that selenoproteins are dispensable for cell viability provided partial GPX4 activity is retained. Conclusively, 200 years after its discovery, a specific and indispensable role for selenium is provided.openIngold, Irina; Berndt, Carsten; Schmitt, Sabine; Doll, Sebastian; Poschmann, Gereon; Buday, Katalin; Roveri, Antonella; Peng, Xiaoxiao; Porto Freitas, Florencio; Seibt, Tobias; Mehr, Lisa; Aichler, Michaela; Walch, Axel; Lamp, Daniel; Jastroch, Martin; Miyamoto, Sayuri; Wurst, Wolfgang; Ursini, Fulvio; Arnér, Elias S J; Fradejas-Villar, Noelia; Schweizer, Ulrich; Zischka, Hans; Friedmann Angeli, José Pedro; Conrad, MarcusIngold, Irina; Berndt, Carsten; Schmitt, Sabine; Doll, Sebastian; Poschmann, Gereon; Buday, Katalin; Roveri, Antonella; Peng, Xiaoxiao; Porto Freitas, Florencio; Seibt, Tobias; Mehr, Lisa; Aichler, Michaela; Walch, Axel; Lamp, Daniel; Jastroch, Martin; Miyamoto, Sayuri; Wurst, Wolfgang; Ursini, Fulvio; Arnér, Elias S J; Fradejas-Villar, Noelia; Schweizer, Ulrich; Zischka, Hans; Friedmann Angeli, José Pedro; Conrad, Marcu
Site-specific overexpression of corticotropin-releasing hormone (CRH) in the mouse brain â modelling central CRH system hyperactivity
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