Prostaglandin E2 stimulates progression-related gene expression in early colorectal adenoma cells

Upregulation of cyclooxygenase-2 (COX-2) and prostaglandin-dependent vascularisation in small adenomatous polyps is an essential part of colon carcinogenesis. To study the underlying cellular mechanisms, LT97 and Caco2 human colorectal tumour cells not expressing endogenous COX-2 were exposed to 1 μM prostaglandin E2 (PGE2) in their medium. At 30 min after addition, expression of c-fos was stimulated 5-fold and 1.3-fold, respectively, depending on the activation of both extracellular signal-regulated kinase and p38. The amount of c-jun in nuclear extracts was increased 20% in LT97 cells. Expression of COX-2 was upregulated 1.7-fold in LT97 cells and 1.5-fold in Caco2 2 h after prostaglandin (PG) addition by a p38-mediated pathway. The known PGE2 target gene vascular endothelial growth factor (VEGF) was not modulated. Effects of sustained PGE2 production were studied in VACO235 cells that have high endogenous COX-2 and in LT97 cells infected with an adenovirus expressing COX-2. Prostaglandin E2 secretion into the medium was 1–2 nM and 250 pM, respectively. Expression of both VEGF and c-fos was high in VACO235 cells. In LT97 cells, COX-2 upregulated c-fos expression and c-jun content in nuclear extracts 1.7- and 1.2-fold, respectively, in a PG-dependent way. This shows that exogenous PGE2 as well as COX-2 overexpression affect signalling and gene expression in a way that enhances tumour progression

Was sind negative Emissionen, und warum brauchen wir sie? Akademienprojekt ‘Energiesysteme der Zukunft’ (ESYS)

Selbst mit ambitionierteren Maßnahmen zur Vermeidung von Emissionen lässt sich Klimaneutralität und damit die Stabilisierung der Temperatur nicht mehr erreichen. Darauf weist der Weltklimarat in seinem sechsten Sachstandsbericht hin. Zusätzlich zu einer schnelleren Reduktion der Emissionen muss CO2 der Atmosphäre entzogen und anschließend eingelagert werden, um nicht vermeidbare Restemissionen auszugleichen, etwa aus der Landwirtschaft. Sogenannte „negative Emissionen“ können zum Beispiel durch Aufforstung erzeugt werden. Es gibt aber eine Reihe weiterer natürlicher und technischer Verfahren, den entnommenen Kohlenstoff dauerhaft einzulagern und aus der Atmosphäre fernzuhalten. In diesem „Kurz erklärt“ skizzieren Fachleute des Akademienprojekts ESYS den aktuellen Forschungsstand, erläutern 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 “Aspen Plus”. 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

O conceito de “Dispositivo universal” (Universalapparat) em Günther Anders

Encontra-se em curso, sensivelmente no último meio século, a finalização de um processo de planetarização da Tecnologia, que, na ordem das causas, terá sido mais proximamente determinado pela Globalização político-económica urdida e imposta pelo Neoliberalismo e mais remotamente influenciado por sucessivas revoluções industriais, desde o século XVIII. Ele implicou uma transformação na própria natureza da Tecnologia, fazendo com que deixasse de ser mero meio (utensílio, ferramenta, instrumento) para determinados fins e se tivesse tornado num ambiente vital e existencial. Günther Anders foi um atento e perspicaz observador e crítico desse fenómeno, que, no seu jargão, concebeu como o do advento de um “Dispositivo universal” (Universalapparat). Dedica-se a primeira parte deste artigo à releitura da interpretação que esse filósofo alemão fez da sua suposta génese e evolução. Na segunda parte, analisa-se esse conceito. Explora-se, na terceira parte, duas consequências filosóficas maiores desse fenómeno.More or less in the last half century, a process of planetarization of Technology is underway, which in the order of causes will have been more directly determined by the politicaleconomic Globalization woven and imposed by the so-called Neoliberalism and more remotely influenced by successive industrial revolutions since the 18th century. It implied a transformation in the nature of Technology, ceasing to be a mere means (utensil, tool, instrument) for certain purposes and becoming a vital and existential environment. Günther Anders was an attentive, perceptive and critical observer of this phenomenon that, in his jargon, he conceived as the advent of a “Universal apparatus” (Universalapparat). I dedicate the first part of this article to reread the German philosopher’s interpretation of his supposed genesis and evolution. In the second part, I analyze this concept. In the third part, I explore two main philosophical consequences of this phenomenon