The recent advances in the development of heterogeneous catalysts and processes for the direct hydrogenation of CO2 to formate/formic acid, methanol, and dimethyl ether are thoroughly reviewed, with special emphasis on thermodynamics and catalyst design considerations. After introducing the main motivation for the development of such processes, we first summarize the most important aspects of CO2 capture and green routes to produce H2. Once the scene in terms of feedstocks is introduced, we carefully summarize the state of the art in the development of heterogeneous catalysts for these important hydrogenation reactions. Finally, in an attempt to give an order of magnitude regarding CO2 valorization, we critically assess economical aspects of the production of methanol and DME and outline future research and development directions.
Abstract. Sookoian S, Gemma C, Fernández Gianotti T, Burgueño A, Alvarez A, González CD, Pirola CJ (Universidad de Buenos Aires, Ciudad Autó noma de Buenos Aires, Buenos Aires, Argentina). Effects of rotating shift work on biomarkers of metabolic syndrome and inflammation. J Intern Med 2007; 261: 285-292.Objective. The major function of the circadian system is the internal cycling of physiological and metabolic events. The present study sought to explore the effect of rotating shift work schedule on leucocyte count and its relationship with risk factors of metabolic syndrome (MS).Design and participants. From a population-based design, 1351 men of self-reported European ancestry were included in a cross-sectional study: 877 day workers were compared with 474 rotating shift workers. Medical history, health examination including anthropometric and arterial blood pressure measurements, a questionnaire on health-related behaviours and biochemical determinations was given to all participants.Results. In comparison with day workers, rotating shift workers had elevated (mean ± SE) body mass index (27.1 ± 0.3 vs. 26.3 ± 0.2, P < 0.0154), waist-hip ratio (0.95 ± 0.01 vs. 0.93 ± 0.01, P < 0.00024), diastolic arterial blood pressure (78 ± 1 vs. 76 ± 1, P < 0.033), fasting insulin (65.5 ± 2.9 vs. 55.9 ± 1.9 pmol L )1 , P < 0.017), Homeostasis Model Assessment index (2.12 ± 0.11 vs. 1.77 ± 0.07, P < 0.0027), triglycerides (1.71 ± 0.1 vs. 1.5 ± 0.1 mmol L )1 , P < 0.002), uric acid (292.7 ± 2.8 vs. 282 ± 3.4 lmol L )1 , P < 0.01) and leucocyte count (7030 ± 84 vs. 6730 ± 58, P < 0.0094). In multiple regression analysis, leucocyte count was correlated with rotating shift work independently of age, smoking, education and components of MS. Conclusion.The odds ratio for MS in rotating shift workers compared with day workers was 1.51 (95% CI 1.01-2.25), independently of age and physical activity. Increased leucocyte count, a biological marker of systemic inflammation, was associated with rotating shift work.
Management of carbon on Earth has become one of the central themes in science, society,a nd politics owing to continuous relocation of carbon from the underground to the atmosphere in the form of carbon dioxide (CO 2 ). This is ac onsequenceo ft he modern life of mankind largely relying on burning or utilising carbon-based fossil fuels, which also causes their depletion. Recently,g lobalw arminga nd consequent climate change have been ascribed to the increasingc oncentration of atmosphericg reen-houseg ases,m ostr epresented by CO 2 ,a nd the world is joining forces to reduce the amount of CO 2 emissiont ot he atmosphere and convertt he "waste" CO 2 into valuable chemicals like polymers and fuels.CO 2 is at hermodynamically stable molecule with the standard formation enthalpy of À393.5 kJ mol À1 . [1] However,C O 2 can be transformed with notable reactivity depending on the chemicale nvironment. Among them catalysis offerss pecific sites to activateC O 2 for its chemical transformation. While CO 2 to polymers is generally enabled by efficient homogeneous catalysts (i.e. reactants and catalyst are in the same liquid phase), large-scale production of useful chemicals like fuels necessitates continuous operation using heterogeneous catalyst to activate CO 2 over its surface. There are several activation methods overc atalyst surfacer eported to date and each methodg enerally leads characteristicr eactivityo fC O 2 and products due to the unique form of activated CO 2 during transformation. Thisa rticle aims at concisely describing the reactivity of CO 2 in general, summarising the state-of-the-art activation methods and also highlighting similarities in different modes of CO 2 activation and correlations to product selectivity to evaluatec oherent views on CO 2 transformation over catalytic surfaces.The general properties of the CO 2 molecule, associatedw ith its reactivity,are summarised in the following four points: 1) Bending of CO 2For the uncharged state, bending of the molecule from its linear equilibrium geometry induces changes in the shape and energy level of the molecular orbitals. Notably,t he more bent the geometry,t he lower the energy level of the in-plane (i.e. to the plane of bending) contribution of 2p u orbital( the lowest unoccupied molecular orbital, LUMO) as shown in Figure 1. Changing the OCO bond angle from 1808 to 1578,t he proportion of the LUMO on the carbon is increased from 61 %t o 78 %, while the distance between carbon ando xygen (< 0.01 )a nd the energy (DE < 0.5 eV) remaina lmostc onstant. [2] Importantly,t his loweringo ft he in-plane 2p u orbital (LUMO) energy upon bending makest he carbon atom electrophilic. 2) Repartition of the ChargesWhen isolated, ap ositive chargec an be found on the carbon atom (the Mulliken's population is + 0.368 e) and negative chargeso nt he two oxygen atoms (with ap opulation of À0.184 e). [3] Ap olarized mediuml ike water can increase the charge on the carbon to + 0.407 e( obtained by DFT using a polarizable continuumm odel with al inear geometry). [3]...
Here we analyze the role of the angiotensinergic system in the differentiation of dendritic cells (DC). We found that human monocytes produce angiotensin II (AII) and express AT1 and AT2 receptors for AII. DC differentiated from human monocytes in the presence of AT1 receptor antagonists losartan or candesartan show very low levels of CD1a expression and poor endocytic and allostimulatory activities. By contrast, DC differentiation in the presence of either the AT2 receptor antagonist PD 123319 or exogenous AII results in the development of nonadherent cells with CD1a expression and endocytic and allostimulatory activities higher than control DC. Similar contrasting effects were observed in mouse DC obtained from bone marrow cultures supplemented with granulocyte-monocyte colony-stimulating factor. DC differentiated in the presence of the AT1 receptor antagonist losartan express lower levels of CD11c, CD40, and Ia and display a lower ability to endocyte horseradish peroxidase (HRP) and to induce antibody responses in vivo, compared with controls. By contrast, DC differentiation in the presence of either the AT2 receptor antagonist PD 123319 or exogenous AII results in cells with high levels of CD11c, CD40, and Ia, as well as high ability to endocyte HRP and to induce antibody responses in vivo. Our results support the notion that the differentiation of DC is regulated by AII.
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