Efficient Teleportation between Remote Single-Atom Quantum Memories

We demonstrate teleportation of quantum bits between two single atoms in distant laboratories. Using a time-resolved photonic Bell-state measurement, we achieve a teleportation fidelity of (88.0+/-1.5)%, largely determined by our entanglement fidelity. The low photon collection efficiency in free space is overcome by trapping each atom in an optical cavity. The resulting success probability of 0.1% is almost 5 orders of magnitude larger than in previous experiments with remote material qubits. It is mainly limited by photon propagation and detection losses and can be enhanced with a cavity-based deterministic Bell-state measurement.Comment: 7 pages, 4 figures, 1 tabl

Generation of single photons from an atom-cavity system

A single rubidium atom trapped within a high-finesse optical cavity is an efficient source of single photons. We theoretically and experimentally study single-photon generation using a vacuum stimulated Raman adiabatic passage. We experimentally achieve photon generation efficiencies of up to 34% and 56% on the D1 and D2 line, respectively. Output coupling with 89% results in record-high efficiencies for single photons in one spatiotemporally well-defined propagating mode. We demonstrate that the observed generation efficiencies are constant in a wide range of applied pump laser powers and virtual level detunings. This allows for independent control over the frequency and wave packet envelope of the photons without loss in efficiency. In combination with the long trapping time of the atom in the cavity, our system constitutes a significant advancement toward an on-demand, highly efficient single-photon source for quantum information processing tasks.Comment: 7 pages, 5 figure

elexiko – das elektronische, lexikografisch-lexikologische korpusbasierte Wortschatzinformationssystem : zur Neukonzeption, Erweiterung und Revision einzelner Angabebereiche

In diesem Beitrag werden wichtige Neukonzeptionen und umfangreiche Nachbearbeitungen einzelner Angabebereiche in elexiko erläutert. Die linguistische Konzeption dieser Angaben stellt eine Weiterentwicklung gegenüber der Konzeption dar, wie sie im Band „Grundfragen der elektronischen Lexikographie. elexiko – das Online-Informationssystem zum deutschen Wortschatz“ (2005) vorgelegt wurde. Betroffen sind z.B. die Angabebereiche der typischen Verwendungen, der sinn- und sachverwandten Wörter und der Besonderheiten des Gebrauchs.This paper presents extensive amendments to the original concept of elexiko, which has been published in the volume „Grundfragen der elektronischen Lexikographie. elexiko – das Online-Informationssystem zum deutschen Wortschatz“ (2005). These complement, for example, information on habitual syntagmatic patterns, sense-related terms, and pragmatics

DNAzymes as Catalysts for l-Tyrosine and Amyloid β Oxidation

Single-stranded deoxyribonucleic acids have an enormous potential for catalysis by applying tailored sequences of nucleotides for individual reaction conditions and substrates. If such a sequence is guanine-rich, it may arrange into a three-dimensional structure called G-quadruplex and give rise to a catalytically active DNA molecule, a DNAzyme, upon addition of hemin. Here, we present a DNAzyme-mediated reaction, which is the oxidation of l-tyrosine toward dityrosine by hydrogen peroxide. With an optimal stoichiometry between DNA and hemin of 1:10, we report an activity of 101.2 ± 3.5 μUnits (μU) of the artificial DNAzyme Dz-00 compared to 33.0 ± 1.8 μU of free hemin. Exemplarily, DNAzymes may take part in neurodegeneration caused by amyloid beta (Aβ) aggregation due to l-tyrosine oxidation. We show that the natural, human genome-derived DNAzyme In1-sp is able to oxidize Aβ peptides with a 4.6% higher yield and a 33.3% higher velocity of the reaction compared to free hemin. As the artificial DNAzyme Dz-00 is even able to catalyze Aβ peptide oxidation with a 64.2% higher yield and 337.1% higher velocity, an in-depth screening of human genome-derived DNAzymes may identify further candidates with similarly high catalytic activity in Aβ peptide oxidation

Optimizing of preoperative computed tomography for diagnosis in patients with peritoneal carcinomatosis

<p>Abstract</p> <p>Background and Objective</p> <p>This study evaluates whether Computer Tomography is an effective procedure for preoperative staging of patients with Peritoneal Carcinomatosis.</p> <p>Method</p> <p>A sample of 37 patients was analyzed with contrast enhanced abdominal Computer Tomography, followed by surgical staging. All Computer Tomography scans were evaluated 3 times by 2 radiologists with one radiologist reviewing 2 times. The efficacy of Computer Tomography was evaluated using the Spearman correlation coefficient. Correlations were analyzed by abdominopelvic region to assess results of the Peritoneal Carcinomatosis Index (PCI) aggregating the 13 regions. Surgical findings were compared to radiological findings.</p> <p>Results</p> <p>Results indicate high correlations between the surgical and radiological Peritoneal Carcinomatosis Indices. Analyses of the intra-class correlation between the first and second reading of one radiologist suggest high intra-observer reliability. Correlations by abdominopelvic region show higher values in the upper and middle regions and relatively lower values in the lower regions and the small bowel (correlation coefficients range between 0.418 and 0.726, p < 0.010; sensitivities range between 50% and 96%; and specificities range between 62% and 100%).</p> <p>Conclusion</p> <p>Computer Tomography represents an effective procedure in the preoperative staging of patients with PC. However, results by abdominopelvic region show lower correlation, therefore suggest lower efficacy. These results are supported by analyses of sensitivity and accuracy by lesion size. This suggests that Computer Tomography is an effective procedure for pre-operative staging but less for determining a tumor's accurate extent.</p

CCL22 as an independent prognostic factor in endometrial cancer patients

Objectives The chemokine CCL22 is recognized for recruiting immunosuppressive regulatory T-cells (Treg) that contribute to disease progression in various tumor entities helping them to evade the host immune response. Our study aims to identify the expressing cell types and to evaluate the prognostic significance of CCL22 secretion and its association with Treg invasion in endometrial cancer (EC), an immunogenic cancer. Methods Specimens from 275 patients with EC and 28 healthy controls were screened immunohistochemically for CCL22. Immunofluorescence double-staining for CCL22 and different immune cell markers was performed. In vitro regulation of CCL22-expression was examined in EC cell lines (Ishikawa+, RL95–2) and human PBMCs in coculture settings via qPCR and ELISA. Results Elevated CCL22 staining in tumor cells and CCL22-positive M1-macrophages in tumordistant areas were significantly associated with increased overall survival (OS). Conversely, high, secretory-appearing staining in the peritumoral and intratumoral stroma correlated with reduced OS. Although the analysis of the in vitro coculture model of epithelial tumor- and immune cells revealed PBMCs as the primary source of CCL22, we could confirm expression of the chemokine also in the EC epithelial cells. Conclusion Our study suggests that CCL22 in EC is associated with OS, dependent on its location and the cell type producing it. Intracellular upregulation and extracellular secretion must be considered separately when investigating CCL22 expressing cell types in EC. These results may provide evidence for CCL22-mediated Treg recruitment in EC as a potential future therapeutic target

Regulatory T cell apoptosis during preeclampsia may be prevented by Gal-2

There are several open questions to be answered regarding the pathophysiology of the development of preeclampsia (PE). Numerous factors are involved in its genesis, such as defective placentation, vascular impairment, and an altered immune response. The activation of the adaptive and innate immune system represents an immunologic, particularity during PE. Proinflammatory cytokines are predominantly produced, whereas immune regulatory and immune suppressive factors are diminished in PE. In the present study, we focused on the recruitment of regulatory T cells (Tregs) which are key players in processes mediating immune tolerance. To identify Tregs in the decidua, an immunohistochemical staining of FoxP3 of 32 PE and 34 control placentas was performed. A clearly reduced number of FoxP3-positive cells in the decidua of preeclamptic women could be shown in our analysis (p = 0.036). Furthermore, CCL22, a well-known Treg chemoattractant, was immunohistochemically evaluated. Interestingly, CCL22 expression was increased at the maternal-fetal interface in PE-affected pregnancies (p(syncytiotrophoblas)(t) = 0.035, p(decidu)(a) = 0.004). Therefore, the hypothesis that Tregs undergo apoptosis at the materno-fetal interface during PE was generated, and verified by FoxP3/TUNEL (TdT-mediated dUTP-biotin nick end labeling) staining. Galectin-2 (Gal-2), a member of the family of carbohydrate-binding proteins, which is known to be downregulated during PE, seems to play a pivotal role in T cell apoptosis. By performing a cell culture experiment with isolated Tregs, we could identify Gal-2 as a factor that seems to prevent the apoptosis of Tregs. Our findings point to a cascade of apoptosis of Tregs at the materno-fetal interface during PE. Gal-2 might be a potential therapeutic target in PE to regulate immune tolerance

GeneTrail 3: advanced high-throughput enrichment analysis

We present GeneTrail 3, a major extension of our web service GeneTrail that offers rich functionality for the identification, analysis, and visualization of deregulated biological processes. Our web service provides a comprehensive collection of biological processes and signaling pathways for 12 model organisms that can be analyzed with a powerful framework for enrichment and network analysis of transcriptomic, miRNomic, proteomic, and genomic data sets. Moreover, GeneTrail offers novel workflows for the analysis of epigenetic marks, time series experiments, and single cell data. We demonstrate the capabilities of our web service in two case-studies, which highlight that GeneTrail is well equipped for uncovering complex molecular mechanisms. GeneTrail is freely accessible at: http://genetrail.bioinf.uni-sb.de

An Elementary Quantum Network of Single Atoms in Optical Cavities

Quantum networks are distributed quantum many-body systems with tailored topology and controlled information exchange. They are the backbone of distributed quantum computing architectures and quantum communication. Here we present a prototype of such a quantum network based on single atoms embedded in optical cavities. We show that atom-cavity systems form universal nodes capable of sending, receiving, storing and releasing photonic quantum information. Quantum connectivity between nodes is achieved in the conceptually most fundamental way: by the coherent exchange of a single photon. We demonstrate the faithful transfer of an atomic quantum state and the creation of entanglement between two identical nodes in independent laboratories. The created nonlocal state is manipulated by local qubit rotation. This efficient cavity-based approach to quantum networking is particularly promising as it offers a clear perspective for scalability, thus paving the way towards large-scale quantum networks and their applications.Comment: 8 pages, 5 figure