Biosynthesis of the protoberberine alkaloid jatrorrhizine

Feeding experiments with distant single or doubly labelled precursors show that the methylene dioxy group of berberine is opened in the formation of jatrorrhizine

Imaging of microwave fields using ultracold atoms

We report a technique that uses clouds of ultracold atoms as sensitive, tunable, and non-invasive probes for microwave field imaging with micrometer spatial resolution. The microwave magnetic field components drive Rabi oscillations on atomic hyperfine transitions whose frequency can be tuned with a static magnetic field. Readout is accomplished using state-selective absorption imaging. Quantitative data extraction is simple and it is possible to reconstruct the distribution of microwave magnetic field amplitudes and phases. While we demonstrate 2d imaging, an extension to 3d imaging is straightforward. We use the method to determine the microwave near-field distribution around a coplanar waveguide integrated on an atom chip.Comment: 11 pages, 4 figure

Supersymmetric Corrections to the Threshold Production of Top Quark Pairs

In this paper we investigate supersymmetric effects to the threshold production cross section of top quark pairs in electron positron annihilation. In particular, we consider the complete one-loop corrections from the strong and weak sector of the Minimal Supersymmetric Standard Model.Comment: 18 pages, 7 figure

Organizing the environmental governance of the rare-earth industry: China’s passive revolution

The rare-earth industry is of strategic importance for China and many ‘clean’ technologies worldwide. Yet the processes of mining, smelting and separating rare-earth ores are heavily polluting. Using a neo-Gramscian perspective in the context of organization studies, this article analyzes the dynamic interactions between government agencies, business and civil society in the development of the environmental governance of China’s rare-earth industry over the past 30 years, with a particular focus on China’s ‘top-down’ passive revolution. Making use of rarely granted access to China’s biggest rare-earth company, one of the country’s key strategic assets, the analysis makes visible the changes of environmental contestations amongst five different governance actors over what we identify as three environmental governance eras in China. Besides offering unique empirical insights into the organizational processes that constitute the dynamically evolving hegemony of China’s rare-earth industry, the article makes three theoretical contributions to the field of organization studies. First, we analyze the changing role of state institutions in a non-Western context, which has been de-emphasized by existing organization scholars. Second, we conceptualize the dynamics of environmental governance in China as a form of top-down ‘passive revolution’. Third, we problematize the dual role of Chinese NGOs as both supporting and challenging state power. Overall, we contribute to our understanding of the organization of governance systems in non-Western contexts, which has been neglected in organizational studies

Dominant BIN1-related centronuclear myopathy (CNM) revealed by lower limb myalgia and moderate CK elevation

We report a BIN1-related CNM family with unusual clinical phenotype. The proband, a 56-year-old man suffered of lower limbs myalgia since the age of 52. Clinical examination showed short stature, mild symmetric eyelid ptosis without ophthalmoplegia, scapular winging and Achilles tendon retraction. A muscle weakness was not noted. CK levels were up to 350 UI/L. Deltoid muscle biopsy showed nuclear centralization and clustering, deep sarcolemmal invaginations and type 1 fiber hypotrophy. Whole body MRI revealed fatty infiltration of posterior legs compartments, lumbar paraspinal and serratus muscles. Myotonic dystrophy type1 and 2, Pompe disease and MTM1 and DNM2-related CNM were ruled out. By sequencing BIN1, we identified a heterozygous pathogenic mutation [c.107C > A (p.A36E)], and we demonstrate that the mutation strongly impairs the membrane tubulation property of the protein. One affected sister carried the same mutation. Her clinical examination and muscle MRI revealed a similar phenotype. Our findings expand the clinical and genetic spectrum of the autosomal dominant CNM associated with BIN1 mutations

Dephasing of quantum dot exciton polaritons in electrically tunable nanocavities

We experimentally and theoretically investigate dephasing of zero dimensional microcavity polaritons in electrically tunable single dot photonic crystal nanocavities. Such devices allow us to alter the dot-cavity detuning in-situ and to directly probe the influence on the emission spectrum of varying the incoherent excitation level and the lattice temperature. By comparing our results with theory we obtain the polariton dephasing rate and clarify its dependence on optical excitation power and lattice temperature. For low excitation levels we observe a linear temperature dependence, indicative of phonon mediated polariton dephasing. At higher excitation levels, excitation induced dephasing is observed due to coupling to the solid-state environment. The results provide new information on coherence properties of quantum dot microcavity polaritons.Comment: Figure 2, panel (b) changed to logarithmic + linear scal

Two-Mechanism Approach in Thermo-Viscoelasticity with Internal Variables

Two-mechanism (more general: multi-mechanism) models have become an important tool for modeling of complex material behavior. In particular, two-mechanism models have been applied for modeling of ratcheting in metal plasticity as well as of steel behavior in case of phase transformations. The characteristic trait of two-mechanism models is the additive decomposition of the inelastic (i.e., plastic or visco-elastic, e.g.) strain into two parts (sometimes called “mechanisms”) in the case of small deformations. In comparison with rheological models, there is an interaction between these  mechanisms allowing to describe important observable effects. We develop a general visco-elastic two-mechanism model in the framework of the internal-variables approach. As a numerical example, we simulate the movement of a rod having a special visco-elastic behavior. An applied periodic stress with nonzero mean value may lead to a ratcheting effect stemming from the coupling of mechanisms

Morita base change in Hopf-cyclic (co)homology

In this paper, we establish the invariance of cyclic (co)homology of left Hopf algebroids under the change of Morita equivalent base algebras. The classical result on Morita invariance for cyclic homology of associative algebras appears as a special example of this theory. In our main application we consider the Morita equivalence between the algebra of complex-valued smooth functions on the classical 2-torus and the coordinate algebra of the noncommutative 2-torus with rational parameter. We then construct a Morita base change left Hopf algebroid over this noncommutative 2-torus and show that its cyclic (co)homology can be computed by means of the homology of the Lie algebroid of vector fields on the classical 2-torus.Comment: Final version to appear in Lett. Math. Phy