Photodynamic Therapy for Granuloma Annulare: More than a Shot in the Dark

Granuloma annulare (GA) is a benign granulomatous and inflammatory skin disorder. The pathogenesis remains enigmatic and convincingly effective treatment options are not available. Inspired by a report showing photodynamic therapy (PDT) to be effective in a single patient with GA, we sought to evaluate this benefit in a series of patients with GA. Observations: PDT was performed in 7 consecutive patients with histologically confirmed GA located at the extremities. First, 20% ALA gel was applied under an occlusive dressing for 5 h, followed by illumination with 100 J/cm(2) by a standard red-light source. In total, 2-3 PDT sessions were performed, with an interval of 2-4 weeks between each session. Treatment was stopped when complete remission was achieved or when GA lesions remained unchanged after 2 consecutive PDT sessions. The overall response rate was 57%. In 2 patients (29%), GA cleared completely, in 2 patients ( 29%) the skin lesions improved markedly and in 3 patients (43%) no clinical response could be observed. Conclusion: These promising results should be evaluated in larger controlled studies. In selected patients, PDT might be a valuable recruit for the sparse armory available to treat GA. Copyright (c) 2008 S. Karger AG, Base

Reactivity Studies of Donor-Acceptor Cyclopropanes: Is there a Relation to Structural and Electronic Properties?

The kinetics of (3+2) cycloaddition reactions of 18 different donor-acceptor cyclopropanes with the same aldehyde were studied by in situ NMR spectroscopy. Increasing the electron density of the donor residue accelerates the reaction by a factor of up to 50 compared to the standard system (donor group=phenyl), whereas electron-withdrawing substituents slow down the reaction by a factor up to 660. This behavior is in agreement with the Hammett substituent parameter σ. The obtained rate constants from the (3+2) cycloadditions correlate well with data from additionally studied (3+n) cycloadditions with a nitrone (n=3) and an isobenzofuran (n=4). A comparison of the kinetic data with the bond lengths in the cyclopropane (obtained by X-ray diffraction and computation), or the 1 H and 13 C NMR shifts, revealed no correlation. However, the computed relaxed force constants of donor-acceptor cyclopropanes proved to be a good indicator for the reactivity of the three-membered ring

Webbasierte Evaluation eines Wissensmanagementsystems

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Algorithms for characterization and trend detection in spatial databases

The number and the size of spatial databases, e.g. for geomarketing, traffic control or environmental studies, are rapidly growing which results in an increasing need for spatial data mining. In this paper, we present new algorithms for spatial characterization and spatial trend analysis. For spatial characterization it is important that class membership of a database object is not only determined by its non-spatial attributes but also by the attributes of objects in its neighborhood. In spatial trend analysis, patterns of change of some non-spatial attributes in the neighborhood of a database object are determined. We present several algorithms for these tasks. These algorithms were implemented within a general framework for spatial data mining providing a small set of database primitives on top of a commercial spatial database management system. A performance evaluation using a real geographic database demonstrates the effectiveness of the proposed algorithms. Furthermore, we show how the algorithms can be combined to discover even more interesting spatial knowledge

Übergangsprozesse von der Schule in die Erwerbstätigkeit in Japan und Deutschland im Kontext von Beruflichkeit und Stratifizierung

Die Autoren betrachten Übergangsprozesse von der Schule in die Erwerbstätigkeit am Beispiel der beiden Nationalstaaten Japan und Deutschland. Vor dem Hintergrund der von ihnen skizzierten, in beiden Staaten gänzlich unterschiedlichen Berufsschulsysteme und gesetzlichen Vorgaben zur Einmündung in die Erwerbstätigkeit untersuchen sie die Rolle der Beruflichkeit im Kontext der Übergangsproblematik und den Einfluss der Stratifizierung. Sie schließen mit einigen Überlegungen dazu, wie die in Japan formal geringe Stratifizierung des Übergangs durch eine indirekte Stratifizierung konterkariert wird. (DIPF/Orig.)The transition process from school into employment is a well known research object in international comparisons. This article will focus on two special issues. On the one hand this will be the comparison between Japan and Germany, two countries with very different (vocational) education systems and labour market entry regulations. On the other hand it will focus on two different aspects in the transition process: One is the role of \u27vocationalism\u27 (Berufskonzept) and the other is the stratification in the systems of education and training. For Japan an indirect type of stratification and no vocationalism can be found. In contrast to that a direct type of stratification is very common in Germany and vocationalism plays a major role in the transition process. Japan, however, even without direct stratification and vocationalism is very successfull in managing the transition process. Here the high ratio of academic education, the relatively unspecific vocational education combined with expanded internal training after entering a company as well as the yet important close link between the employee and the company are important factors. (DIPF/Orig.

Hidden magnetic order in CuNCN

We report a comprehensive experimental and theoretical study of the quasi-one-dimensional quantum magnet CuNCN. Based on magnetization measurements above room temperature as well as muon spin rotation and electron spin resonance measurements, we unequivocally establish the localized Cu+2-based magnetism and the magnetic transition around 70 K, both controversially discussed in the previous literature. Thermodynamic data conform to the uniform-spin-chain model with a nearest-neighbor intrachain coupling of about 2300 K, in remarkable agreement with the microscopic magnetic model based on density functional theory band-structure calculations. Using exact diagonalization and the coupled-cluster method, we derive a collinear antiferromagnetic order with a strongly reduced ordered moment of about 0.4 mu_B, indicating strong quantum fluctuations inherent to this quasi-one-dimensional spin system. We re-analyze the available neutron-scattering data, and conclude that they are not sufficient to resolve or disprove the magnetic order in CuNCN. By contrast, spectroscopic techniques indeed show signatures of long-range magnetic order below 70 K, yet with a rather broad distribution of internal field probed by implanted muons. We contemplate the possible structural origin of this effect and emphasize peculiar features of the microstructure studied with synchrotron powder x-ray diffraction.Comment: 17 pages, 17 figures, 1 tabl

HOW TO MODEL SERVICE PRODUCTIVITY FOR DATA ENVELOPMENT ANALYSIS? A META-DESIGN APPROACH

The rise of the service economy is increasingly reflected in the IS discipline. Since services depend on a co-creation of value between service providers and customers, productivity measurement needs to account for both points of view. Contrasting this evolution, current productivity management concepts often remain limited to the firm instead of focusing on dyadic relationships. Also, software tools frequently constitute expert systems that are focused on solving an optimization problem based on a linear program, but do not guide users in setting up a suitable productivity model in the first place. To account for this need, we conceptualize a software tool support for setting up productivity models for services. Our concept encompasses an extended Data Envelopment Analysis (DEA) approach as its analytical core, but in addition features various tools that help users to collaboratively define a productivity measurement model. Since the suitability of such a model is contingent on the environment in which it is applied, the proposed concept constitutes a meta-design that is intended to be applicable to a class of productivity management problems. As an outlook we present ideas for further research focusing on the implementation and evaluation of IT artefacts compliant with the proposed meta-design

Electronic properties of wurtzite GaAs: A correlated structural, optical, and theoretical analysis of the same polytypic GaAs nanowire

III-V compound semiconductor nanowires are generally characterized by the coexistence of zincblende and wurtzite structures. So far, this polytypism has impeded the determination of the electronic properties of the metastable wurtzite phase of GaAs, which thus remain highly controversial. In an effort to obtain new insights into this topic, we cross-correlate nanoscale spectral imaging by near-field scanning optical microscopy with a transmission electron microscopy analysis of the very same polytypic GaAs nanowire dispersed onto a Si wafer. Thus, spatially resolved photoluminescence spectra could be unambiguously assigned to nanowire segments whose structure is known with lattice-resolved accuracy. An emission energy of 1.528 eV was observed from extended zincblende segments, revealing that the dispersed nanowire was under uniaxial strain presumably due to interaction with its supporting substrate. These crucial information and the emission energy obtained for extended pure wurtzite segments were used to perform envelope function calculations of zincblende quantum disks in a wurtzite matrix as well as the inverse structure. In these calculations, we varied the fundamental bandgap, the electron mass, and the band offset between zincblende and wurtzite GaAs. From this multi-parameter comparison with the experimental data, we deduced that the bandgap between the Γ8 conduction and A valence band ranges from 1.532 to 1.539 eV in strain-free wurtzite GaAs, and estimated values of 1.507 to 1.514 eV for the Γ7–A bandgap. Address correspondenc

Anisotropy-induced spin disorder in intergrown, ferrimagnetic Fe7_7 S8_8 polytypes

The monosulfides of the pyrrhotite omission series (Fe$_{1−}$S, 0<≤0.125) are important remanence carriers for paleomagnetic reconstruction of the Earth\u27s crust and extraterrestrial materials. The ferrimagnetic Fe$_7$S$_8$ polytypes are the endmembers, and their stacking modulations of full and vacant layers generate different magnetic anisotropy properties due to the cation-vacancy configurations. In this study, intergrown long-range ordered polytypes with four- and threefold modulation, i.e., 4C and 3C pyrrhotite, were prepared in a diffusion-driven process by quenching of a natural pyrrhotite crystal with randomized vacancies. In addition, a third constituent with coherence lengths of a few nanometers, denoted 3C*, was found that exhibits spin-glass behavior at about 10 K due to local magnetic anisotropies arising from vacancy-density variations. The concomitant occurrence of this nano-scale constituent with spin disorder and the long-range ordered polytypes indicate competitive diffusion-driven processes during Fe$_7$S$_8$ formation. Such information provides insight into the provenance and genesis of ferrimagnetic pyrrhotite in Earth and extraterrestrial systems and in a broader sense into vacancy-induced materials