Exact Lagrangian submanifolds in simply-connected cotangent bundles

We consider exact Lagrangian submanifolds in cotangent bundles. Under certain additional restrictions (triviality of the fundamental group of the cotangent bundle, and of the Maslov class and second Stiefel–Whitney class of the Lagrangian submanifold) we prove such submanifolds are Floer-cohomologically indistinguishable from the zero-section. This implies strong restrictions on their topology. An essentially equivalent result was recently proved independently by Nadler [16], using a different approach.     

Immunomagnetic nanoparticle-based sandwich chemiluminescence-ELISA for the enrichment and quantification of E. coli

Rapid methods for the quantification of Escherichia coli are required for the monitoring of faecal contamination in water to secure public health. The immunomagnetic separation (IMS) offers rapid enrichment and purification of bacteria in complex matrices and is compatible with immunoassays. By means of this technique, non-target cells and matrix components which might interfere with subsequent analytical methods are removed. We present the synthesis of magnetic nanoparticles (MNPs) and covalent coupling to antibodies against the enterobacterial common antigen (ECA) for use with IMS. Quantification was carried out with a chemiluminescence-based sandwich enzyme-linked immunosorbent assay (ELISA). Our anti-ECA-MNPs allow for a group-specific enrichment of bacterial cells, which can be combined with a species-specific analytical method. The particles were used along with commercially available magnetic columns for the selective enrichment of E. coli from 10-mL water samples. The volumetric enrichment factor was 9. For enriched samples, the limit of detection was reduced from 5.0?×?10⁶ cells·mL^-1 to 2.6?×?10⁵ cells·mL^-1. Using 200 µL anti-ECA-MNPs, we determined a recovery of 97?±?6% for a sample containing 10⁶ cells·mL^-1 and 89?±?2% for a sample containing 10⁷ cells·mL^-1. The overall time for cell enrichment and detection was 3 h 45 min.     

An elastic network model to identify characteristic stress response genes

Exposing eukaryotic cells to a toxic compound and subsequent gene expression profiling may allow the prediction of selected toxic effects based on changes in gene expression. This objective is complicated by the observation that compounds with different modes of toxicity cause similar changes in gene expression and that a global stress response affects many genes. We developed an elastic network model of global stress response with nodes representing genes which are connected by edges of graded coexpression. The expression of only few genes have to be known to model the global stress response of all but a few atypical responder genes. Those required genes and the atypical response genes are shown to be good biomarker for tox predictions. In total, 138 experiments and 13 different compounds were used to train models for different toxicity classes. The deduced biomarkers were shown to be biologically plausible. A neural network was trained to predict the toxic effects of compounds from profiling experiments. On a validation data set of 189 experiments with 16 different compounds the accuracy of the predictions was assessed: 14 out of 16 compounds have been classified correctly. Derivation of model based biomarkers through the elastic network approach can naturally be extended to other areas beyond toxicology since subtle signals against a broad response background are common in biological studies.     

Generation of near-infrared frequency combs from a MgF₂ whispering gallery mode resonator

We report on generation of a 20 nm wide, 35 GHz repetition rate optical frequency comb in a magnesium fluoride whispering gallery mode resonator pumped with 2 mW of 1543 nm light. The high efficiency of comb generation is associated with the small anomalous group velocity dispersion of the resonator. Growth dynamics of the comb is studied and compared with earlier theoretical predictions.     

Metal organic frameworks showing hydrocarbon adsorption properties commensurate with their pore structure

Commensurate adsorption occurs when the number of molecules adsorbed per unit cell relates to the symmetry of the framework and its topology. While rare in zeolite materials, commensurate adsorption has been observed in several MOF materials. In some MOF materials, several molecules having dimensions within a limited size range show this effect. This paper describes the commensurate adsorption properties of three MOF materials and also two MOFs showing unusual combined structure-composition adsorption features.     

2‐Hydroxytorularhodin,a New Xanthophyll from the Red Yeast Sporobolomyces coprosmae

A new hydroxylated carotenoic acid was isolated from the red yeast Sporobolomyces coprosmae and unambiguously identified as 2‐hydroxytorularhodin ( 1 ), i.e., (all‐E)‐3′,4′‐didehydro‐2‐hydroxy‐β,ψ‐caroten‐16′‐oic acid, by application of extensive 1D and 2D NMR techniques (gCOSY, gHSQC, gHMBC, DQS, gTOCSY, and ROESY). Hydroxylation of carotenoids at C(2) is uncommon in nature, very rare in fungi, and unprecedented for torularhodin.