Single spin stochastic optical reconstruction microscopy

We experimentally demonstrate precision addressing of single quantum emitters by combined optical microscopy and spin resonance techniques. To this end we utilize nitrogen-vacancy (NV) color centers in diamond confined within a few ten nanometers as individually resolvable quantum systems. By developing a stochastic optical reconstruction microscopy (STORM) technique for NV centers we are able to simultaneously perform sub diffraction-limit imaging and optically detected spin resonance (ODMR) measurements on NV spins. This allows the assignment of spin resonance spectra to individual NV center locations with nanometer scale resolution and thus further improves spatial discrimination. For example, we resolved formerly indistinguishable emitters by their spectra. Furthermore, ODMR spectra contain metrology information allowing for sub diffraction-limit sensing of, for instance, magnetic or electric fields with inherently parallel data acquisition. As an example, we have detected nuclear spins with nanometer scale precision. Finally, we give prospects of how this technique can evolve into a fully parallel quantum sensor for nanometer resolution imaging of delocalized quantum correlations.Comment: 9 pages, 4 figure

Wörterbuchportale : Fragen der Benutzerführung

In diesem Beitrag geht es um Fragen der Benutzerführung in lexikografisch-lexikologischen Portalen, und zwar inbesondere um die Portale OWID (Mannheim) und „Wörterbuch-Portal“ (Berlin). Diese werden mit ihrer jeweiligen Konzeption sowie ihrem technischen Aufbau vorgestellt und dann aus Benutzersicht bewertet. An Vorschläge für die Weiterentwicklung dieser Angebote schließen sich einige grundsätzliche Überlegungen zur Zukunft lexikografischer Portale an.This contribution discusses questions of user interaction in dictionary portals. The dictionary portals OWID (Institut für Deutsche Sprache, Mannheim) and „Wörterbuch-Portal“ (Berlin-Brandenburgische Akademie der Wissenschaften) are presented as showcases. Their conceptual as well as their technical layer are discussed in detail. Both portals are evaluated with regard to their interaction with their prospective users. Suggestions for the advancement of these portals as well as some considerations about the future of internet-based dictionary portals conclude this paper

Gene flow in admixed populations and implications for the conservation of the Western honeybee, Apis mellifera

Anthropogenic activity, especially modern apiculture, has considerable impact on the natural distribution of the Western honeybee, Apismellifera, leading to the spread, replacement and fragmentation of many subspecies. This creates demand for the conservation of some subspecies, in particular, Apismelliferamellifera, which once was widely distributed in Western Europe and nowadays is endangered through habitat loss and fragmentation. Moreover, A.m.mellifera may be further endangered by hybridisation in populations that now occur in artificial sympatry with other subspecies. Here, we quantify and compare individual hybridisation between sympatric and allopatric honeybee populations of A.m.mellifera and A.m.carnica using microsatellite markers and a Bayesian model-based approach. We had a special focus on pure breeding populations, which are a major tool in honeybee conservation. Our results demonstrate that subspecies are still highly differentiated, but gene flow is not prevented by the current management strategies, creating urgent demand for an improved conservation management of A.m.mellifera. However, the occurrence of a high number of pure individuals might suggest that some sort of hybrid barrier acts against the complete admixture of the two subspecie

Perfect alignment and preferential orientation of nitrogen-vacancy centers during CVD growth of diamond on (111) surfaces

Synthetic diamond production is key to the development of quantum metrology and quantum information applications of diamond. The major quantum sensor and qubit candidate in diamond is the nitrogen-vacancy (NV) color center. This lattice defect comes in four different crystallographic orientations leading to an intrinsic inhomogeneity among NV centers that is undesirable in some applications. Here, we report a microwave plasma-assisted chemical vapor decomposition (MPCVD) diamond growth technique on (111)-oriented substrates that yields perfect alignment ($94\pm2$) of as-grown NV centers along a single crystallographic direction. In addition, clear evidence is found that the majority ($74\pm4$) of the aligned NV centers were formed by the nitrogen being first included in the (111) growth surface and then followed by the formation of a neighboring vacancy on top. The achieved homogeneity of the grown NV centers will tremendously benefit quantum information and metrology applications.Comment: 6 pages, 4 figures, changes to previous version: added acknowledgemen

BMC Bioinformatics / QCScreen: a software tool for data quality control in LC-HRMS based metabolomics

Background: Metabolomics experiments often comprise large numbers of biological samples resulting in huge amounts of data. This data needs to be inspected for plausibility before data evaluation to detect putative sources of error e.g. retention time or mass accuracy shifts. Especially in liquid chromatography-high resolution mass spectrometry (LC-HRMS) based metabolomics research, proper quality control checks (e.g. for precision, signal drifts or offsets) are crucial prerequisites to achieve reliable and comparable results within and across experimental measurement sequences. Software tools can support this process. Results: The software tool QCScreen was developed to offer a quick and easy data quality check of LC-HRMS derived data. It allows a flexible investigation and comparison of basic quality-related parameters within user-defined target features and the possibility to automatically evaluate multiple sample types within or across different measurement sequences in a short time. It offers a user-friendly interface that allows an easy selection of processing steps and parameter settings. The generated results include a coloured overview plot of data quality across all analysed samples and targets and, in addition, detailed illustrations of the stability and precision of the chromatographic separation, the mass accuracy and the detector sensitivity. The use of QCScreen is demonstrated with experimental data from metabolomics experiments using selected standard compounds in pure solvent. The application of the software identified problematic features, samples and analytical parameters and suggested which data files or compounds required closer manual inspection. Conclusions: QCScreen is an open source software tool which provides a useful basis for assessing the suitability of LC-HRMS data prior to time consuming, detailed data processing and subsequent statistical analysis. It accepts the generic mzXML format and thus can be used with many different LC-HRMS platforms to process both multiple quality control sample types as well as experimental samples in one or more measurement sequences

Bericht der Arbeitsgruppe "Open-Access-Publikationsplattformen"

Die Open-Access-Strategie des Landes Berlin von 2015 formuliert den Anspruch: "Als langfristiges Ziel wird der Aufbau einer landesweiten Open-Access- Infrastruktur für Monografien, Sammelbände und Zeitschriften in Kooperation mit an wissenschaftlichen Einrichtungen agierenden Infrastrukturdienstleistern, sowie mit in Berlin ansässigen Verlagen und Publikationsdienstleistern angestrebt." Eine landesweite Berliner Open-Access- Publikationsinfrastruktur soll dabei von den vorhandenen infrastrukturellen und wissenschaftlichen Expertisen mehrerer, kooperativ agierender Einrichtungen in Berlin profitieren und qualitativ hochwertige Publikationen zu fairen Kosten umsetzen. Die Arbeitsgruppe "Open-Access- Publikationsplattformen" mit Vertreter/innen mehrerer Berliner Forschungseinrichtungen wurde beauftragt, dafür notwendige Vorarbeiten zu leisten. So wurden im ersten Teil des Berichtes die an Berliner wissenschaftlichen Einrichtungen bereits bestehenden Publikationsinfrastrukturen erfasst. Im zweiten Teil wurden drei Modelle für den Aufbau einer landesweiten Open-Access-Publikationsinfrastruktur für Monografien, Sammelbände und Zeitschriften beschrieben. The Berlin Open Access Strategy claims: "It is a long-term goal to establish a Berlin-wide open access infrastructure for monographs, anthologies and periodicals – as a cooperation of infrastructure service providers located at research institutions as well as Berlin-based publishers and publishing service providers." A Berlin-wide open access publishing infrastructure should be based on the existing infrastructural and scholarly expertise of several, cooperating institutions in Berlin and result in high-quality publications at fair costs. A working group "Open Access Publishing Platforms" consisting of representatives of several Berlin research institutions was set up and commissioned to carry out the necessary preliminary work. The first part reports on existing publication infrastructures run by Berlin research institutions. The second part describes three possible model for re- structuring and setting up a Berlin-wide open access publishing infrastructure for monographs, anthologies and journals

A mutation affecting the sodium/proton exchanger, SLC9A6, causes mental retardation with tau deposition

We have studied a family with severe mental retardation characterized by the virtual absence of speech, autism spectrum disorder, epilepsy, late-onset ataxia, weakness and dystonia. Post-mortem examination of two males revealed widespread neuronal loss, with the most striking finding being neuronal and glial tau deposition in a pattern reminiscent of corticobasal degeneration. Electron microscopic examination of isolated tau filaments demonstrated paired helical filaments and ribbon-like structures. Biochemical studies of tau demonstrated a preponderance of 4R tau isoforms. The phenotype was linked to Xq26.3, and further analysis identified an in-frame 9 base pair deletion in the solute carrier family 9, isoform A6 (SLC9A6 gene), which encodes sodium/hydrogen exchanger-6 localized to endosomal vesicles. Sodium/hydrogen exchanger-6 is thought to participate in the targeting of intracellular vesicles and may be involved in recycling synaptic vesicles. The striking tau deposition in our subjects reveals a probable interaction between sodium/proton exchangers and cytoskeletal elements involved in vesicular transport, and raises the possibility that abnormalities of vesicular targeting may play an important role in more common disorders such as Alzheimer's disease and autism spectrum disorder

Schmallenberg virus pathogenesis, tropism and interaction with the innate immune system of the host

Schmallenberg virus (SBV) is an emerging orthobunyavirus of ruminants associated with outbreaks of congenital malformations in aborted and stillborn animals. Since its discovery in November 2011, SBV has spread very rapidly to many European countries. Here, we developed molecular and serological tools, and an experimental in vivo model as a platform to study SBV pathogenesis, tropism and virus-host cell interactions. Using a synthetic biology approach, we developed a reverse genetics system for the rapid rescue and genetic manipulation of SBV. We showed that SBV has a wide tropism in cell culture and “synthetic” SBV replicates in vitro as efficiently as wild type virus. We developed an experimental mouse model to study SBV infection and showed that this virus replicates abundantly in neurons where it causes cerebral malacia and vacuolation of the cerebral cortex. These virus-induced acute lesions are useful in understanding the progression from vacuolation to porencephaly and extensive tissue destruction, often observed in aborted lambs and calves in naturally occurring Schmallenberg cases. Indeed, we detected high levels of SBV antigens in the neurons of the gray matter of brain and spinal cord of naturally affected lambs and calves, suggesting that muscular hypoplasia observed in SBV-infected lambs is mostly secondary to central nervous system damage. Finally, we investigated the molecular determinants of SBV virulence. Interestingly, we found a biological SBV clone that after passage in cell culture displays increased virulence in mice. We also found that a SBV deletion mutant of the non-structural NSs protein (SBVΔNSs) is less virulent in mice than wild type SBV. Attenuation of SBV virulence depends on the inability of SBVΔNSs to block IFN synthesis in virus infected cells. In conclusion, this work provides a useful experimental framework to study the biology and pathogenesis of SBV