50 research outputs found
Enhancerless Cytomegalovirus Is Capable of Establishing a Low-Level Maintenance Infection in Severely Immunodeficient Host Tissues but Fails in Exponential Growth
Major immediate-early transcriptional enhancers are genetic control elements that act, through docking with host transcription factors, as a decisive regulatory unit for efficient initiation of the productive virus cycle. Animal models are required for studying the function of enhancers paradigmatically in host organs. Here, we have sought to quantitatively assess the establishment, maintenance, and level of in vivo growth of enhancerless mutants of murine cytomegalovirus in comparison with those of an enhancer-bearing counterpart in models of the immunocompromised or immunologically immature host. Evidence is presented showing that enhancerless viruses are capable of forming restricted foci of infection but fail to grow exponentially
Was sind negative Emissionen, und warum brauchen wir sie? Akademienprojekt âEnergiesysteme der Zukunftâ (ESYS)
Selbst mit ambitionierteren MaĂnahmen zur Vermeidung von Emissionen lĂ€sst sich KlimaneutralitĂ€t und damit die Stabilisierung der Temperatur nicht mehr erreichen. Darauf weist der Weltklimarat in seinem sechsten Sachstandsbericht hin. ZusĂ€tzlich zu einer schnelleren Reduktion der Emissionen muss CO2 der AtmosphĂ€re entzogen und anschlieĂend eingelagert werden, um nicht vermeidbare Restemissionen auszugleichen, etwa aus der Landwirtschaft. Sogenannte ânegative Emissionenâ können zum Beispiel durch Aufforstung erzeugt werden. Es gibt aber eine Reihe weiterer natĂŒrlicher und technischer Verfahren, den entnommenen Kohlenstoff dauerhaft einzulagern und aus der AtmosphĂ€re fernzuhalten. In diesem âKurz erklĂ€rtâ skizzieren Fachleute des Akademienprojekts ESYS den aktuellen Forschungsstand, erlĂ€utern Verfahren zur CO2-Entnahme und benennen deren jeweiligen Vor- und Nachteile
Comparative assessment of gasification based coal power plants with various CO2 capture technologies producing electricity and hydrogen
Seven different types of gasification-based coal conversion processes for producing mainly electricity and in some cases hydrogen (H2), with and without carbon dioxide (CO2) capture, were compared on a consistent basis through simulation studies. The flowsheet for each process was developed in a chemical process simulation tool âAspen Plusâ. The pressure swing adsorption (PSA), physical absorption (Selexol), and chemical looping combustion (CLC) technologies were separately analyzed for processes with CO2 capture. The performances of the above three capture technologies were compared with respect to energetic and exergetic efficiencies, and the level of CO2 emission. The effect of air separation unit (ASU) and gas turbine (GT) integration on the power output of all the CO2 capture cases is assessed. Sensitivity analysis was carried out for the CLC process (electricity-only case) to examine the effect of temperature and water-cooling of the air reactor on the overall efficiency of the process. The results show that, when only electricity production in considered, the case using CLC technology has an electrical efficiency 1.3% and 2.3% higher than the PSA and Selexol based cases, respectively. The CLC based process achieves an overall CO2 capture efficiency of 99.9% in contrast to 89.9% for PSA and 93.5% for Selexol based processes. The overall efficiency of the CLC case for combined electricity and H2 production is marginally higher (by 0.3%) than Selexol and lower (by 0.6%) than PSA cases. The integration between the ASU and GT units benefits all three technologies in terms of electrical efficiency. Furthermore, our results suggest that it is favorable to operate the air reactor of the CLC process at higher temperatures with excess air supply in order to achieve higher power efficiency
Wenn nicht jetzt, wann dann â wie die Energiewende gelingt (Impuls), Akademienprojekt âEnergiesysteme der Zukunftâ (ESYS)
Thermoresponsive Poly(2-oxazoline) Block Copolymers Exhibiting Two Cloud Points: Complex Multistep Assembly Behavior
In vivo biomolecular imaging of zebrafish embryos using confocal Raman spectroscopy
Zebrafish embryos provide a unique opportunity to visualize complex biological processes, yet conventional imaging modalities are unable to access intricate biomolecular information without compromising the integrity of the embryos. Here, we report the use of confocal Raman spectroscopic imaging for the visualization and multivariate analysis of biomolecular information extracted from unlabeled zebrafish embryos. We outline broad applications of this method in: (i) visualizing the biomolecular distribution of whole embryos in three dimensions, (ii) resolving anatomical features at subcellular spatial resolution, (iii) biomolecular profiling and discrimination of wild type and ÎRD1 mutant Mycobacterium marinum strains in a zebrafish embryo model of tuberculosis and (iv) in vivo temporal monitoring of the wound response in living zebrafish embryos. Overall, this study demonstrates the application of confocal Raman spectroscopic imaging for the comparative bimolecular analysis of fully intact and living zebrafish embryos
Lymphoma Cell Apoptosis in the Liver Induced by Distant Murine Cytomegalovirus Infection
Cytomegalovirus (CMV) poses a threat to the therapy of hematopoietic malignancies by hematopoietic stem cell transplantation, but efficient reconstitution of antiviral immunity prevents CMV organ disease. Tumor relapse originating from a minimal residual leukemia poses another threat. Although a combination of risk factors was supposed to enhance the incidence and severity of transplantation-associated disease, a murine model of a liver-adapted B-cell lymphoma has previously shown a survival benefit and tumor growth inhibition by nonlethal subcutaneous infection with murine CMV. Here we have investigated the underlying antitumoral mechanism. Virus replication proved to be required, since inactivated virions or the highly attenuated enhancerless mutant mCMV-ÎMIEenh did not impact the lymphoma in the liver. Surprisingly, the dissemination-deficient mutant mCMV-ÎM36 inhibited tumor growth, even though this virus fails to infect the liver. On the other hand, various strains of herpes simplex viruses consistently failed to control the lymphoma, even though they infect the liver. A quantitative analysis of the tumor growth kinetics identified a transient tumor remission by apoptosis as the antitumoral effector mechanism. Tumor cell colonies with cells surviving the CMV-induced âapoptotic crisisâ lead to tumor relapse even in the presence of full-blown tissue infection. Serial transfer of surviving tumor cells did not indicate a selection of apoptosis-resistant genetic variants. NK cell activity of CD49b-expressing cells failed to control the lymphoma upon adoptive transfer. We propose the existence of an innate antitumoral mechanism that is triggered by CMV infection and involves an apoptotic signal effective at a distant site of tumor growth
(De-)ZentralitĂ€t in technischen Szenarien: Materialien zur Stellungnahme âZentrale und dezentrale Elemente im Energiesystem. Der richtige Mix fĂŒr eine stabile und nachhaltige Versorgung"
Die Materialien â(De-)ZentralitĂ€t in technischen Szenarienâ enthalten eine detaillierte Charakterisierung zentraler und dezentraler Energiesysteme aus technischer Sicht, sowie eine Auswertung von Energieszenarien aus Studien, die verschiedene DezentralitĂ€tsaspekte berĂŒcksichtigen. Die dargestellten Ergebnisse bildeten die Basis fĂŒr die weiterfĂŒhrende interdisziplinĂ€re Betrachtung, deren Ergebnisse in der Stellungnahme âZentrale und dezentrale Elemente im Energiesystem. Der richtige Mix fĂŒr eine stabile und nachhaltige Versorgungâ nachzulesen sind