332 research outputs found

    Steigerung der Energieeffizienz einer integrierten Heimnetzwerkinfrastruktur

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    Zur Realisierung von Applikationen aus den Bereichen Smart Home, Ambient Assisted Living und E-Health ist es notwendig, eine Vielzahl von kleinen ressourcenbeschränkten Systemen zu vernetzen. Dazu eignen sich drahtlose Kommunikationslösungen mit niedrigen Datenraten und energiesparender Arbeitsweise. Damit erhalten neben den bereits weitverbreiteten hochratigen Technologien, wie WLAN, PLC und Ethernet, niederratige Kommunikationstechnologien Einzug in den Heimbereich. Eine intelligente Kombination und Interaktion zwischen beiden Netzwerken verspricht vielfältige Vorteile. Wenn z.B. zunehmend Switches, Access Points oder Mediengeräte mit niederratigen Schnittstellen ausgestattet werden, erhalten diese nicht nur Zugriff auf Heimautomatisierungsgeräte, sondern können auch über diese energiesparende Schnittstelle untereinander kommunizieren. Ein solches dediziertes Signalisierungsnetzwerk kann dazu dienen, das hochratige Netzwerk zu parametrisieren. In diesem Beitrag wird ein Verfahren vorgestellt, das über die niederratige Technologie Informationen über benötigte und nicht benötigte hochratige Schnittstellen austauscht. Unbenutzte Schnittstellen werden gezielt abgeschaltet. Mit Hilfe von Simulationen wird gezeigt, dass solche Verfahren erhebliche Energieeinsparungen der Heimnetzwerkinfrastruktur ermöglichen

    The role of membrane lipids in the induction of macrophage apoptosis by microparticles

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    Microparticles are membrane-derived vesicles that are released from cells during activation or cell death. These particles can serve as mediators of intercellular cross-talk and induce a variety of cellular responses. Previous studies have shown that macrophages undergo apoptosis after phagocytosing microparticles. Here, we have addressed the hypothesis that microparticles trigger this process via lipid pathways. In these experiments, microparticles induced apoptosis in primary macrophage cells or cell lines (RAW 264.7 or U937) with up to a 5-fold increase. Preincubation of macrophages with phosphatidylinositol-3,5-bisphosphate (PtdIns(3,5)BP) reduced the microparticle-induced apoptosis in a dose-dependent manner. PtdIns(3,5)BP is a specific inhibitor of the acid sphingomyelinase and thus can block the generation of pro-apoptotic ceramides. Similarly, the pre-incubation of macrophages with PtdIns(3,5)BP prevented microparticle-induced upregulation of caspase 8, which is a major target molecule of ceramide action in the apoptosis pathway. PtdIns(3,5)BP, however, had no effect on the spontaneous rate of apoptosis. To evaluate further signaling pathways induced by microparticles, the extracellular signal regulated kinase (ERK-) 1 was investigated. This kinase plays a role in activating phospholipases A2 which cleaves membrane phospholipids into arachidonic acid; microparticles have been suggested to be a preferred substrate for phospholipases A2. As shown in our experiments, microparticles strongly increased the amount of phosphorylated ERK1/2 in RAW 264.7 macrophages in a time-dependent manner, peaking 15 min after co-incubation. Addition of PD98059, a specific inhibitor of ERK1, prevented the increase in apoptosis of RAW 264.7 macrophages. Together, these data suggest that microparticles perturb lipid homeostasis of macrophages and thereby induce apoptosis. These results emphasize the importance of biolipids in the cellular cross-talk of immune cells. Based on the fact that in clinical situations with excessive cell death such as malignancies, autoimmune diseases and following chemotherapies high levels of circulating microparticles might modulate phagocytosing cells, a suppression of the immune response might occur due to loss of macrophage

    Rhizosphere Organic Anions Play a Minor Role in Improving Crop Species' Ability to Take Up Residual Phosphorus (P) in Agricultural Soils Low in P Availability

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    Many arable lands have accumulated large reserves of residual phosphorus (P) and a relatively large proportion of soil P is less available for uptake by plants. Root released organic anions are widely documented as a key physiological strategy to enhance P availability, while limited information has been generated on the contribution of rhizosphere organic anions to P utilization by crops grown in agricultural soils that are low in available P and high in extractable Ca, Al, and Fe. We studied the role of rhizosphere organic anions in P uptake from residual P in four common crops Triticum aestivum, Avena sativa, Solanum tuberosum, and Brassica napus in low- and high-P availability agricultural soils from long-term fertilization field trials in a mini-rhizotron experiment with four replications. Malate was generally the dominant organic anion. More rhizosphere citrate was detected in low P soils than in high P soil. B. napus showed 74–103% increase of malate in low P loam, compared with clay loam. A. sativa had the greatest rhizosphere citrate concentration in all soils (5.3–15.2 μmol g−1 root DW). A. sativa also showed the highest level of root colonization by arbuscular mycorrhizal fungi (AMF; 36 and 40%), the greatest root mass ratio (0.51 and 0.66) in the low-P clay loam and loam respectively, and the greatest total P uptake (5.92 mg P/mini-rhizotron) in the low-P loam. B. napus had 15–44% more rhizosphere acid phosphatase (APase) activity, ~0.1–0.4 units lower rhizosphere pH than other species, the greatest increase in rhizosphere water-soluble P in the low-P soils, and the greatest total P uptake in the low-P clay loam. Shoot P content was mainly explained by rhizosphere APase activity, water-soluble P and pH within low P soils across species. Within species, P uptake was mainly linked to rhizosphere water soluble P, APase, and pH in low P soils. The effects of rhizosphere organic anions varied among species and they appeared to play minor roles in improving P availability and uptake

    Ultra-bright single photon source based on an atomically thin material

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    Solid-state single photon sources are central building blocks in quantum communication networks and on-chip quantum information processing. Atomically thin crystals were established as possible candidates to emit non-classical states of light, however, the performance of monolayer-based single photon sources has so far been lacking behind state-of-the-art devices based on volume crystals. Here, we implement a single photon source based on an atomically thin sheet of WSe2 coupled to a spectrally tunable optical cavity. It is characterized by a high single photon purity with a g(2)(0)g^{(2)}(0) value as low as 4.7±0.7%4.7 \pm 0.7 \% and a record-high first lens brightness of linearly polarized photons as large as 65±4%65 \pm 4 \%. Interestingly, the high performance of our devices allows us to observe genuine quantum interference phenomena in a Hong-Ou-Mandel experiment. Our results demonstrate that open cavities and two-dimensional materials constitute an excellent platform for ultra-bright quantum light sources: the unique properties of such two-dimensional materials and the versatility of open cavities open an inspiring avenue for novel quantum optoelectronic devices.Comment: 12 pages, 7 figure

    Wildfire selectivity for land cover type: does size matter ?

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    Previous research has shown that fires burn certain land cover types disproportionally to their abundance. We used quantile regression to study land cover proneness to fire as a function of fire size, under the hypothesis that they are inversely related, for all land cover types. Using five years of fire perimeters, we estimated conditional quantile functions for lower (avoidance) and upper (preference) quantiles of fire selectivity for five land cover types - annual crops, evergreen oak woodlands, eucalypt forests, pine forests and shrublands. The slope of significant regression quantiles describes the rate of change in fire selectivity (avoidance or preference) as a function of fire size. We used Monte-Carlo methods to randomly permutate fires in order to obtain a distribution of fire selectivity due to chance. This distribution was used to test the null hypotheses that 1) mean fire selectivity does not differ from that obtained by randomly relocating observed fire perimeters; 2) that land cover proneness to fire does not vary with fire size. Our results show that land cover proneness to fire is higher for shrublands and pine forests than for annual crops and evergreen oak woodlands. As fire size increases, selectivity decreases for all land cover types tested. Moreover, the rate of change in selectivity with fire size is higher for preference than for avoidance. Comparison between observed and randomized data led us to reject both null hypotheses tested (a = 0.05) and to conclude it is very unlikely the observed values of fire selectivity and change in selectivity with fire size are due to chance.Funding: This paper was supported by the Fundação para a Ciência e Tecnologia Ph.D. Grant SFRH/BD/40398/2007. JMCP participated in this research under the framework of research projects ‘‘Forest fire under climate, social and economic changes in Europe, the Mediterranean and other fire-affected areas of the world (FUME)’’, EC FP7 Grant Agreement No. 243888. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscrip

    Personal preference, experience, intuition and school of surgery dominate the use of wound drainage in dermatosurgery

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    Hintergrund Die Verwendung von Drainagesystemen in der Dermatochirurgie erfolgt bislang ohne evidenzbasierte Daten. Indikationen, Komplikationen und Kontraindikationen werden traditionell von Operateur zu Operateur weitergegeben, sind jedoch bisher nicht definiert. Methodik Es wurde eine internetbasierte Umfrage erstellt und unter den Mitgliedern der DGDC e. V. (Deutsche Gesellschaft für Dermatochirurgie e. V.) ausgesandt. Abgefragt wurden das allgemeine Behandlungsverhalten im deutschsprachigen Raum in Bezug auf die Anwendung der Wunddrainage nach dermatologischen Operationen sowie die Nutzungsgewohnheiten und Erfahrungen der Kollegen mit Drainage-assoziierten Komplikationen. Ergebnisse Es haben 12,73 % der angeschriebenen DGDC-Mitglieder den Fragebogen beantwortet. Drainagen werden überwiegend im klinischen Umfeld eingesetzt, es werden alle abgefragten Drainagesysteme verwendet. Ausmaß und Komplexität des Eingriffs sind die wesentlichen Kriterien bei der Indikationsstellung. Der Einsatz von Drainagen ist abhängig vom Alter des Teilnehmers und erfolgt mehrheitlich bei Patienten, bei denen Komplikationen im postoperativen Verlauf erwartet werden (Adipositas, Nikotinabusus, Diabetiker). Diskussion Zusammenfassend verwendet die Mehrzahl der Teilnehmer Wunddrainagen und dies mehrheitlich intuitiv. Einheitliche fixe evidenzbasierte Parameter rund um die Verwendung von Wunddrainagen fehlen. Bei der Beurteilung der Notwendigkeit einer Wunddrainage scheint ein individuell unterschiedlich ausgeprägtes Sicherheitsbedürfnis bei den einen und „eminenzbasiertes“ Handeln bei den anderen Dermatochirurgen eine große Rolle zu spielen.Background The use of drainage systems in dermatosurgery has so far been carried out without evidence-based data. The indications, complications and contraindications are traditionally passed on from surgeon to surgeon but have so far not been defined. Method An Internet-based survey was created and sent out to members of the German Society for Dermatosurgery (DGDC). The questions were on the general treatment approach in German language countries with reference to the use of wound drainage following dermatological operations as well as the utilization habits and experiences with drainage-associated complications. Results Of the DGDC members contacted 12.73% completed the questionnaire. Drainages were predominantly used in the clinical environment and all drainage systems in question were used. The extent and complexity of the intervention were essential criteria when evaluating the indications. The use of drainages was dependent on the age of the participant and mostly carried out in patients where complications in the postoperative course were to be expected (e.g. obesity, nicotine use, diabetes). Conclusion In summary, the majority of the participants used wound drainages and mostly intuitively. Uniform and fixed evidence-based parameters for the use of wound drainages are lacking. In the assessment of the necessity for a wound drainage, an individually expressed need of safety seems to play a large role for some dermatosurgeons and an eminence-based action for others
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