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31.
The response of giant magnetoresistance (GMR) devices depends critically on the film microstructure, with parameters such
as layer thickness and interfacial abruptness being crucial. This paper presents results obtained using high resolution electron
microscopy (HREM), chemical mapping and atom probe microanalysis. Local variations in the magnetic properties are induced
by the microstructure and also when the films are patterned to form small elements. These lead to changes in the magnetization
reversal mechanism. Some results of the studies of the magnetization reversal carried out using in situ in Lorentz transmission electron microscopy (LTEM) magnetizing experiments are also included. 相似文献
32.
Dr. Cosima Dufour Dr. Joachim Wink Dr. Michael Kurz Dr. Herbert Kogler Helene Olivan Serge Sablé Winfried Heyse Dr. Martin Gerlitz Dr. Luigi Toti Antje Nußer Dr. Astrid Rey Dr. Cedric Couturier Dr. Armin Bauer Dr. Mark Brönstrup 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(50):16123-16128
In an antibiotic lead discovery program, the known strain Streptomyces armeniacus DSM19369 has been found to produce three new natural products when cultivated on a malt‐containing medium. The challenging structural elucidation of the isolated compounds was achieved by using three independent methods, that is, chemical degradation followed by NMR spectroscopy, a computer‐assisted structure prediction algorithm, and X‐ray crystallography. The compounds, named armeniaspirol A–C ( 2 – 4 ), exhibit a compact, hitherto unprecedented chlorinated spiro[4.4]non‐8‐ene scaffold. Labeling experiments with [1‐13C] acetate, [1,2‐13C2] acetate, and [U‐13C] proline suggest a biosynthesis through a rare two‐chain mechanism. Armeniaspirols displayed moderate to high in vitro activities against Gram‐positive pathogens such as methicillin‐resistant S. aureus (MRSA) or vancomycin resistant E. faecium (VRE). As analogue 2 was active in vivo in an MRSA sepsis model, and showed no development of resistance in a serial passaging experiment, it represents a new antibiotic lead structure. 相似文献
33.
34.
Miranda KM Dutton AS Ridnour LA Foreman CA Ford E Paolocci N Katori T Tocchetti CG Mancardi D Thomas DD Espey MG Houk KN Fukuto JM Wink DA 《Journal of the American Chemical Society》2005,127(2):722-731
The recent determination that Angeli's salt may have clinical application as a nitrogen oxide donor for treatment of cardiovascular diseases such as heart failure has led to renewed interest in the mechanism and products of thermal decomposition of Angeli's salt under physiological conditions. In this report, several mechanisms are evaluated experimentally and by quantum mechanical calculations to determine whether HNO is in fact released from Angeli's salt in neutral, aerobic solution. The mechanism of product autoxidation is also considered. 相似文献
35.
Chunrui Sun Matthew J. O'Connor Daesung Lee Donald J. Wink Robert D. Milligan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(12):3261-3264
Installation of amino functionality on organic molecules through direct C N bond formation is an important research objective. To achieve this goal, a 1,2‐aminocyanation reaction was developed. The reaction occurs through the formation of pyrazolines by means of a formal dipolar cycloaddition of cyclic α,β‐unsaturated ketones with lithium trimethylsilyldiazomethane followed by novel protonolytic N N bond cleavage under mild conditions. This two‐step process provides a diverse array of structurally complex free and mono‐alkylated α‐amino ketones in excellent yields. 相似文献
36.
Crich D Li H Yao Q Wink DJ Sommer RD Rheingold AL 《Journal of the American Chemical Society》2001,123(24):5826-5828
37.
38.
Rubin M Markov J Chuprakov S Wink DJ Gevorgyan V 《The Journal of organic chemistry》2003,68(16):6251-6256
The cross-coupling of a variety of terminal alkynes 1 with allenylphosphine oxides 2 catalyzed by a Pd(OAc)(2)-TDMPP system provided conjugated endo-enynes 3 solely, while the TCPC-catalyzed reaction of the same regents led to the exclusive formation of exo-isomers 4. The mechanistic rationale for these selective transformations was proposed. Synthetic usefulness of the prepared exo-enyne 4 was demonstrated in the synthesis of multisubstituted diarylbenzylphosphine oxides 5 via the Pd-catalyzed [4+2]-benzannulation reaction. 相似文献
39.
Lupinus albus cell cultures secrete a large set of hydrolases into their medium with a small number of highly abundant proteins. We have investigated the protein composition of the medium with two different methods, two-dimensional gel electrophoresis-electrospray ionisation tandem mass spectrometry (ESI-MS-MS) and enzymatic analysis. The proteomic approach revealed the presence of several abundant proteins that had been overlooked using standard enzyme assays, e.g. subtilisin-like protease, glucan 1,3-beta-glucosidase, alpha-amylase, chitinase, thaumatin-like protein, and a secretory pathogenesis-related protein. Several low-abundant proteins were readily detectable by enzymatic assays (peroxidases, phosphatase), but could not be found by ESI-MS-MS. Both data sets support the assumed lytic function of the medium, which appears to be similar to that of the plant vacuole. 相似文献
40.
Bonalde I Yanoff BD Salamon MB Van Harlingen DJ Chia EM Mao ZQ Maeno Y 《Physical review letters》2000,85(22):4775-4778
We report measurements of the magnetic penetration depth in single crystals of Sr2RuO4 down to 0.04 K using a tunnel-diode based, self-inductive technique. We observe a power law temperature dependence below 0.8 K, with no sign of a second phase transition nor of a crossover predicted for a multiband superconductor. A power law dependence suggests that the gap function has nodes, inconsistent with candidate p-wave states. We argue that nonlocal effects, rather than impurity scattering, can explain the observed T2 dependence instead of the T-linear behavior expected for line nodes. 相似文献