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291.
292.
Verena Jung Benjamin Balke Gerhard H. Fecher Vadim Ksenofontov Claudia Felser 《Hyperfine Interactions》2008,184(1-3):15-21
57Fe Mössbauer spectroscopic studies of Co2Mn1???x Fe x Al based Heusler compounds are presented. The cubic structure type was found for all samples of the series in XRD studies. However, a mixture of the cubic B2 and L21 structure types are not unambiguously distinguished by XRD. The present study gives evidence for a mixture of the L21 structure with additions of a large amount of B2 like disorder. The isomer shifts and hyperfine magnetic fields on 57Fe atoms are compared with theoretical values from CPA calculations. 相似文献
293.
Verena Bögelein Frank Duzaar Paolo Marcellini 《Archive for Rational Mechanics and Analysis》2013,210(1):219-267
We consider the evolution problem associated with a convex integrand ${f : \mathbb{R}^{Nn}\to [0,\infty)}$ satisfying a non-standard p, q-growth assumption. To establish the existence of solutions we introduce the concept of variational solutions. In contrast to weak solutions, that is, mappings ${u\colon \Omega_T \to \mathbb{R}^n}$ which solve $$ \partial_tu-{\rm div} Df(Du)=0 $$ weakly in ${\Omega_T}$ , variational solutions exist under a much weaker assumption on the gap q ? p. Here, we prove the existence of variational solutions provided the integrand f is strictly convex and $$\frac{2n}{n+2} < p \le q < p+1.$$ These variational solutions turn out to be unique under certain mild additional assumptions on the data. Moreover, if the gap satisfies the natural stronger assumption $$ 2\le p \le q < p+ {\rm min}\big \{1,\frac{4}{n} \big \},$$ we show that variational solutions are actually weak solutions. This means that solutions u admit the necessary higher integrability of the spatial derivative Du to satisfy the parabolic system in the weak sense, that is, we prove that $$u\in L^q_{\rm loc}\big(0,T; W^{1,q}_{\rm loc}(\Omega,\mathbb{R}^N)\big).$$ 相似文献
294.
Kolk A Pautke C Wiener E Schott V Wolff KD Horch HH Rummeny EJ 《Magnetic resonance imaging》2008,26(8):1167-1174
Objective
The cause of enophthalmos as a late complication after orbital reconstruction is poorly investigated. Multislice CT (MSCT) is usually employed for its assessment, in spite of limitations regarding soft tissue depiction/imaging, as well as the implication of radiation and production of artifacts. Magnetic resonance imaging (MRI) has been shown to be a valuable alternative. The aim of this study was to establish a bony and soft tissue orbital volume calculation method based on different high-resolution MRI sequences compared to MSCT.Materials and Methods
Thirty-seven patients were included in this prospective study investigating the origin of enophthalmos present 3–4 months after complex orbital reconstruction. Morphological and dimensional changes of the orbit, eye globes, extraocular muscles and fat content were investigated 3–4 months after surgery. To assess the site and size of bony and soft tissue changes in the traumatized orbits, we used MSCT and MR images as well as corresponding 3-D reconstructions.Results
All enophthalmic orbits revealed a significant bony volume increase compared to the contralateral side as well as a reduced sagittal eye projection. Mean orbital volume enlargements of 1.0 cm3 lead to 0.93 mm enophthalmos (P<.05). Hardly any fatty atrophy could be depicted by the different MRI techniques.Conclusions
For soft tissue depiction of the orbit, MRI was superior to MSCT. Particularly, proton density weighting proved to be the best sequence for soft tissue volume segmentation, allowing determination of the cause and degree of posttraumatic enophthalmos in reconstructed orbits. 相似文献295.
Liang Yue Verena Wulf Shan Wang Itamar Willner 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(35):12366-12373
The evolution of networks is a fundamental unresolved issue in developing the area of systems chemistry. We introduce a versatile rewiring mechanism that leads to the emergence of nucleic‐acid‐based constitutional dynamic networks (CDNs). A two‐component constituent AA′ functionalized with a Mg2+‐ion‐dependent DNAzyme activator unit forms a complex with an intact hairpin HBB′ composed of B and B′ sequences. Cleavage of HBB′ leads to the two‐component constituent BB′, and its rewiring with AA′ yields CDN X composed of the equilibrated constituents AA′, AB′, BA′, and BB′. In analogy, subjecting AA′ to an intact hairpin HCC′ leads to the formation of CDN Y consisting of AA′, AC′, CA′, and CC′. Subjecting AA′ to the mixture of HBB′ and HCC′ evolves the [3×3] CDN Z, composed of nine constituents, thus demonstrating hierarchical adaptive properties. Furthermore, the DNAzyme units associated with the constituents are applied to tailor emerging catalytic functions from the different CDNs. 相似文献
296.
We present a novel solar cell structure, the “buried emitter solar cell”. This concept is designed for decoupling the metallisation geometry from the geometry of the carrier collecting p–n junction in back‐contacted (and in particular back‐junction) solar cells without requiring electrical insulation by dielectric layers. The most prominent features of this device structure are a carrier collecting emitter that covers close to 100% of the total cell area and an effective electrical insulation between emitter and base metallisation via a p+–n+ junction. The experimental results presented in this paper report a 19.5% efficient “buried emitter solar cell”, where 50% of the solar cell's rear side exhibit a p+–n+ junction. This preparation technique implies covering a boron‐doped p‐type emitter with an n‐type surface layer that can be efficiently surface‐passivated by thermal oxidation. All structuring of this cell has been performed by laser processing without any photo‐lithography. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
297.
298.
Marchetti-Deschmann M Lehner A Peterseil V Sövegjarto F Hochegger R Allmaier G 《Analytical and bioanalytical chemistry》2011,400(8):2403-2414
Wheat variety identification based on one-step single-grain wheat extraction and fast capillary gel electrophoresis-on-a-chip
(CGE-on-a-chip) analyses was evaluated for 15 different wheat varieties grown in Austria. The results of the capillary-based
separation system were compared to the internationally accepted method from the International Union for the Protection of
New Varieties of Plants which is based on time-consuming sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE)
analysis. Comparable protein patterns were observed making the CGE-on-a-chip system a promising tool for high-throughput analysis
in food control. For the development of a robust method protein extraction, shelf life of wheat extracts and the instrument’s
variability were evaluated. It turned out that a one-step single-grain wheat extraction allowed the sample to be stored at
4 °C for up to 4 weeks without losing any valuable protein information. Furthermore, the technical variation of the whole
method is very low making the biological variation of the selected wheat grains the only uncertain factor. Additionally, two
unsupervised statistical methods (hierarchical cluster analysis and principal component analysis) were used for variety identification.
Identification was successful for a reduced data set of 14 samples from five different wheat varieties making the combination
of CGE-on-a-chip analysis of one-step single-grain extraction in combination with automatic data evaluation a promising tool
for fast wheat differentiation (within a day). 相似文献
299.
Schattel V Hinselmann G Jahn A Zell A Laufer S 《Journal of chemical information and modeling》2011,51(3):670-679
The goal of this paper is to present and describe a novel 2D- and 3D-QSAR (quantitative structure-activity relationship) binary classification data set for the inhibition of c-Jun N-terminal kinase-3 with previously unpublished activities for a diverse set of compounds. JNK3 is an important pharmaceutical target because it is involved in many neurological disorders. Accordingly, the development of JNK3 inhibitors has gained increasing interest. 2D and 3D versions of the data set were used, consisting of 313 (70 actives) and 249 (60 actives) compounds, respectively. All compounds, for which activity was only determined for the racemate, were removed from the 3D data set. We investigated the diversity of the data sets by an agglomerative clustering with feature trees and show that the data set contains several different scaffolds. Furthermore, we show that the benchmarks can be tackled with standard supervised learning algorithms with a convincing performance. For the 2D problem, a random decision forest classifier achieves a Matthew's correlation coefficient of 0.744, the 3D problem could be modeled with a Matthew's correlation coefficient of 0.524 with 3D pharmacophores and a support vector machine. The performance of both data sets was evaluated within a nested 10-fold cross-validation. We therefore suggest that the data set is a reasonable basis for generating QSAR models for JNK3 because of its diverse composition and the performance of the classifiers presented in this study. 相似文献
300.
Arenediazonium tetrafluoroborates react with crotonaldehyde (2-butenal) in methanol in the presence of catalytic amounts of Pd(OAc)2 to yield mainly 4,4-dimethoxy-1-butenylarenes. In most of the examples studied, small amounts of an isomeric byproduct were formed, presumably 3,3-dimethoxy-1-methylenepropylarenes. Because crotonaldehyde and arenediazonium salts are cheap and readily available, this reaction is a convenient access to protected 4-arylbutenals. 相似文献