Sustainable Hydrogen from Bio-Oil - Catalytic Steam Reforming of Acetic Acid as a Model Oxygenate

Studies were conducted with acetic acid (HAc) as model oxygenate for the design of active and stable catalysts for steam reforming of bio-oil. Pt/ZrO2 catalysts were prepared by wet impregnation technique. The Pt/ZrO2 catalysts showed high activities at initial time on stream, but lost its activity for steam reforming (H2 production) rapidly. During HAc/H2O reaction over Pt/ZrO2, conversion was close to 100% and constant for 3 hr, however, yields of products changed with time. In the beginning (5 min), H2 and CO2 were the main products, CH4 and CO were observed in small quantities. During HAc/H2O reaction over ZrO2 (without Pt), HAc conversion was close to 90%. The conversion of HAc and yields of the products were constant for 3 hr. However, no steam reforming activity (H2 and CO) was observed, and only acetone and CO2 were observed as products. Both Pt/ZrO2 and ZrO2 were very active for HAc conversion. However, H2 and CO, i.e., steam reforming products, were produced only over Pt/ZrO2 and not over ZrO2. ZrO2 showed acetone yields similar to those observed over Pt/ZrO2 after 25 min time on stream. The presence of acetone in the product mixture and formation of deposits on ZrO2 indicated a role for acetone in catalyst deactivation

Catalyst deactivation during steam reforming of acetic acid over Pt/ZrO2.

Steam reforming of acetic acid as a model compound present in bio-oil over Pt/ZrO2 catalysts has been investigated. Pt/ZrO2 yields steam reforming products (i.e., H2, CO, CO2) to the amounts predicted by thermodynamic equilibrium; however, conversion and yields dropped rapidly with time on course. The deactivation was due to blockage of active sites by coke/oligomer formed. This report clarifies cause of the deactivation during steam reforming of acetic acid. It was found that many products can be formed from acetic acid on ZrO2, such as acetone. The experimental results confirmed that aldol condensation of acetone took place on ZrO2 to give larger compounds which can easily become deposits to block active sites for steam reforming. In order to develop durable catalysts for steam reforming of bio-oil, support should be designed to enhance activation of water, minimize dehydration reactions and thus oligomer formation

Surface generation of a cobalt-derived water oxidation electrocatalyst developed in a neutral HCO 3 − /CO 2 system

Solid state NMR/Biophysical Organic Chemistr

Microwave assisted heterogeneous catalysis: effects of varying oxygen concentrations on the oxidative coupling of methane

The oxidative coupling of methane was investigated over alumina supported La2O3/CeO2 catalysts under microwave dielectric heating conditions at different oxygen concentrations. It was observed that, at a given temperature using microwave heating, selectivities for both ethane and ethylene were notably higher when oxygen was absent than that in oxygen/methane mixtures. The differences were attributed to the localised heating of microwave radiation resulting in temperature inhomogeneity in the catalyst bed. A simplified model was used to estimate the temperature inhomogeneity; the temperature at the centre of the catalyst bed was 85 °C greater than that at the periphery when the catalyst was heated by microwaves in a gas mixture with an oxygen concentration of 12.5% (v/v), and the temperature difference was estimated to be 168 °C in the absence of oxygen

Programming of adipose tissue miR-483-3p and GDF-3 expression by maternal diet in type 2 diabetes.

Nutrition during early mammalian development permanently influences health of the adult, including increasing the risk of type 2 diabetes and coronary heart disease. However, the molecular mechanisms underlying such programming are poorly defined. Here we demonstrate that programmed changes in miRNA expression link early-life nutrition to long-term health. Specifically, we show that miR-483-3p is upregulated in adipose tissue from low-birth-weight adult humans and prediabetic adult rats exposed to suboptimal nutrition in early life. We demonstrate that manipulation of miR-483-3p levels in vitro substantially modulates the capacity of adipocytes to differentiate and store lipids. We show that some of these effects are mediated by translational repression of growth/differentiation factor-3, a target of miR-483-3p. We propose that increased miR-483-3p expression in vivo, programmed by early-life nutrition, limits storage of lipids in adipose tissue, causing lipotoxicity and insulin resistance and thus increasing susceptibility to metabolic disease.This work was funded by the BBSRC (project grants BB/F-15364/1 and BB/F-14279/1). SEO is a British Heart Foundation Senior Fellow (FS/09/029/27902), MB is an MRC Senior Fellow and AEW is a BBSRC Professorial Fellow. KS and SEO are members of the MRC Centre for Obesity and Related Metabolic Diseases (MRC-CORD), which also provided a studentship for MW. KS is a member of the European Union COST Action BM0602

Gene-chip studies of adipogenesis-regulated microRNAs in mouse primary adipocytes and human obesity

<p>Abstract</p> <p>Background</p> <p>Adipose tissue abundance relies partly on the factors that regulate adipogenesis, i.e. proliferation and differentiation of adipocytes. While components of the transcriptional program that initiates adipogenesis is well-known, the importance of microRNAs in adipogenesis is less well studied. We thus set out to investigate whether miRNAs would be actively modulated during adipogenesis and obesity.</p> <p>Methods</p> <p>Several models exist to study adipogenesis <it>in vitro</it>, of which the cell line 3T3-L1 is the most well known, albeit not the most physiologically appropriate. Thus, as an alternative, we produced EXIQON microarray of brown and white <it>primary </it>murine adipocytes (prior to and following differentiation) to yield global profiles of miRNAs.</p> <p>Results</p> <p>We found 65 miRNAs regulated during <it>in vitro </it>adipogenesis in primary adipocytes. We evaluated the similarity of our responses to those found in non-primary cell models, through literature data-mining. When comparing primary adipocyte profiles, with those of cell lines reported in the literature, we found a high degree of difference in 'adipogenesis' regulated miRNAs suggesting that the model systems may not be accurately representing adipogenesis. The expression of 10 adipogenesis-regulated miRNAs were studied using real-time qPCR and then we selected 5 miRNAs, that showed robust expression, were profiled in subcutaneous adipose tissue obtained from 20 humans with a range of body mass indices (BMI, range = 21-48, and all samples have U133+2 Affymetrix profiles provided). Of the miRNAs tested, mir-21 was robustly expressed in human adipose tissue and positively correlated with BMI (R2 = 0.49, p < 0.001).</p> <p>Conclusion</p> <p>In conclusion, we provide a preliminary analysis of miRNAs associated with primary cell <it>in vitro </it>adipogenesis and demonstrate that the inflammation-associated miRNA, mir-21 is up-regulated in subcutaneous adipose tissue in human obesity. Further, we provide a novel transcriptomics database of EXIQON and Affymetrix adipocyte profiles to facilitate data mining.</p

The Discovery of LOX-1, its Ligands and Clinical Significance

LOX-1 is an endothelial receptor for oxidized low-density lipoprotein (oxLDL), a key molecule in the pathogenesis of atherosclerosis.The basal expression of LOX-1 is low but highly induced under the influence of proinflammatory and prooxidative stimuli in vascular endothelial cells, smooth muscle cells, macrophages, platelets and cardiomyocytes. Multiple lines of in vitro and in vivo studies have provided compelling evidence that LOX-1 promotes endothelial dysfunction and atherogenesis induced by oxLDL. The roles of LOX-1 in the development of atherosclerosis, however, are not simple as it had been considered. Evidence has been accumulating that LOX-1 recognizes not only oxLDL but other atherogenic lipoproteins, platelets, leukocytes and CRP. As results, LOX-1 not only mediates endothelial dysfunction but contributes to atherosclerotic plaque formation, thrombogenesis, leukocyte infiltration and myocardial infarction, which determine mortality and morbidity from atherosclerosis. Moreover, our recent epidemiological study has highlighted the involvement of LOX-1 in human cardiovascular diseases. Further understandings of LOX-1 and its ligands as well as its versatile functions will direct us to ways to find novel diagnostic and therapeutic approaches to cardiovascular disease

Photobiocatalytic chemistry of oxidoreductases using water as the electron donor

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