Fischer–Tropsch Synthesis Over Zr-Promoted Co/γ-Al2O3 Catalysts

Two Zr-modified alumina supports were synthetized containing the same amount of Zr but a different distribution of this modifier over the alumina surface. These supports, together with the unmodified alumina carrier, were used to prepare three cobalt-based catalysts which were characterized and tested under relevant Fischer–Tropsch conditions. The three catalysts presented very similar porosity and cobalt dispersion. The addition of Zr nor its distribution enhanced the catalyst reducibility. The catalyst activity was superior when using a carrier consisting of large ZrO2 islands over the alumina surface. The use of a carrier with a homogeneous Zr distribution had however, a detrimental effect. Moreover, a faster initial deactivation rate was observed for the Zr-promoted catalysts, fact that may explain this contradictory effect of Zr on activity. Finally, the addition of Zr showed a clear enhancement of the selectivity to long chain hydrocarbons and ethylene, especially when Zr was well dispersed

Characterization of a novel PTEN mutation in MDA-MB-453 breast carcinoma cell line

<p>Abstract</p> <p>Background</p> <p>Cowden Syndrome (CS) patients with germ line point mutations in the <it>PTEN </it>gene are at high risk for developing breast cancer. It is believed that cells harboring these mutant <it>PTEN </it>alleles are predisposed to malignant conversion. This article will characterize the biochemical and biological properties of a mutant PTEN protein found in a commonly used metastatic breast cancer cell line.</p> <p>Methods</p> <p>The expression of PTEN in human breast carcinoma cell lines was evaluated by Western blotting analysis. Cell line MDA-MB-453 was selected for further analysis. Mutation analysis of the <it>PTEN </it>gene was carried out using DNA isolated from MDA-MB-453. Site-directed mutagenesis was used to generate a PTEN E307K mutant cDNA and ectopic expressed in PC3, U87MG, MCF7 and <it>Pten</it>^-/-mouse embryo fibroblasts (MEFS). Histidine (His)-tagged PTEN fusion protein was generated in <it>Sf9 </it>baculovirus expression system. Lipid phosphatase and ubiquitination assays were carried out to characterize the biochemical properties of PTEN E307K mutant. The intracellular localization of PTEN E307K was determined by subcellular fractionation experiments. The ability of PTEN E307K to alter cell growth, migration and apoptosis was analyzed in multiple PTEN-null cell lines.</p> <p>Results</p> <p>We found a mutation in the <it>PTEN </it>gene at codon 307 in MDA-MB-453 cell line. The glutamate (E) to lysine (K) substitution rendered the mutant protein to migrate with a faster mobility on SDS-PAGE gels. Biochemically, the PTEN E307K mutant displayed similar lipid phosphatase and growth suppressing activities when compared to wild-type (WT) protein. However, the PTEN E307K mutant was present at higher levels in the membrane fraction and suppressed Akt activation to a greater extent than the WT protein. Additionally, the PTEN E307K mutant was polyubiquitinated to a greater extent by NEDD4-1 and displayed reduced nuclear localization. Finally, the PTEN E307K mutant failed to confer chemosensitivity to cisplatinum when re-expressed in <it>Pten</it>^-/-MEFS.</p> <p>Conclusions</p> <p>Mutation at codon 307 in PTEN C2 loop alters its subcellular distribution with greater membrane localization while being excluded from the cell nucleus. This mutation may predispose breast epithelial cells to malignant transformation. Also, tumor cells harboring this mutation may be less susceptible to the cytotoxic effects of chemotherapeutics.</p

Quality changes and shelf-life prediction of a fresh fruit and vegetables purple smoothie

The sensory, microbial and bioactive quality changes of untreated (CTRL) and mild heat−treated (HT; 90 ºC/45 s) smoothies were studied and modelled throughout storage (5, 15 and 25 ºC). The overall acceptability was better preserved in HT samples being highly correlated (hierarchical clustering) with the flavour. The sensory quality data estimated smoothie shelf−life (CTRL/HT) of 18/55 (at 5 ºC), 4.5/12 (at 15 ºC), 2.4/5.8 (at 25 ºC) days. The yeast and moulds growth rate was lower in HT compared to CTRL while a lag phase for mesophiles/psychrophiles was observed in HT−5/15 ºC. HT and 5 ºC−storage stabilized the phenolics content. FRAP reported the best correlation (R2=0.94) with the studied bioactive compounds, followed by ABTS (R2=0.81) while DPPH was the total antioxidant capacity method with the lowest adjustment (R2=0.49). Conclusively, modelling was used to estimate the shelf−life of a smoothie based on quality retention after a short time−high temperature heat treatment that better preserved microbial and nutritional quality during storage.The financial support of this research was provided by the Ministerio Español de Economía y Competitividad MINECO (Projects AGL2013−48830−C2−1−R and AGL2013−48993−C2−1−R) and by FEDER funds. G.A. González−Tejedor thanks to Panamá Government for the scholarship to carry out his PhD Thesis. A. Garre (BES−2014−070946) is grateful to the MINECO for awarding him a pre−doctoral grant. We are also grateful to E. Esposito and N. Castillejo for their skilful technical assistance

The triple combination of tenofovir, emtricitabine and efavirenz shows synergistic anti-HIV-1 activity in vitro: a mechanism of action study

<p>Abstract</p> <p>Background</p> <p>Tenofovir disoproxil fumarate (TDF), emtricitabine (FTC), and efavirenz (EFV) are the three components of the once-daily, single tablet regimen (Atripla) for treatment of HIV-1 infection. Previous cell culture studies have demonstrated that the double combination of tenofovir (TFV), the parent drug of TDF, and FTC were additive to synergistic in their anti-HIV activity, which correlated with increased levels of intracellular phosphorylation of both compounds.</p> <p>Results</p> <p>In this study, we demonstrated the combinations of TFV+FTC, TFV+EFV, FTC+EFV, and TFV+FTC+EFV synergistically inhibit HIV replication in cell culture and synergistically inhibit HIV-1 reverse transcriptase (RT) catalyzed DNA synthesis in biochemical assays. Several different methods were applied to define synergy including median-effect analysis, MacSynergy^®II and quantitative isobologram analysis. We demonstrated that the enhanced formation of dead-end complexes (DEC) by HIV-1 RT and TFV-terminated DNA in the presence of FTC-triphosphate (TP) could contribute to the synergy observed for the combination of TFV+FTC, possibly through reduced terminal NRTI excision. Furthermore, we showed that EFV facilitated efficient formation of stable, DEC-like complexes by TFV- or FTC-monophosphate (MP)-terminated DNA and this can contribute to the synergistic inhibition of HIV-1 RT by TFV-diphosphate (DP)+EFV and FTC-TP+EFV combinations.</p> <p>Conclusion</p> <p>This study demonstrated a clear correlation between the synergistic antiviral activities of TFV+FTC, TFV+EFV, FTC+EFV, and TFV+FTC+EFV combinations and synergistic HIV-1 RT inhibition at the enzymatic level. We propose the molecular mechanisms for the TFV+FTC+EFV synergy to be a combination of increased levels of the active metabolites TFV-DP and FTC-TP and enhanced DEC formation by a chain-terminated DNA and HIV-1 RT in the presence of the second and the third drug in the combination. This study furthers the understanding of the longstanding observations of synergistic anti-HIV-1 effects of many NRTI+NNRTI and certain NRTI+NRTI combinations in cell culture, and provides biochemical evidence that combinations of anti-HIV agents can increase the intracellular drug efficacy, without increasing the extracellular drug concentrations.</p

Rate and duration of hospitalisation for acute pulmonary embolism in the real-world clinical practice of different countries : Analysis from the RIETE registry

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Catalytic screening of Au/CeO2-MOx/Al2O3 catalysts (M= La,Ni,Cu,Fe,Cr,Y) in the CO-PrOx reaction

In this work, a series of Au/CeO2-MOx/Al2O3 catalysts has been prepared and evaluated in the PrOx reaction. Within the series of dopants Fe and Cu containing samples enhanced the catalytic performance of the parent Au/CeO2/Al2O3 catalyst being copper the most efficient promoter. For both samples an enhanced oxygen storage capacity (OSC) is registered and accounts for the high CO oxidation activity. More particularly, the Au/CeO2-CuOx/Al2O3 catalyst successfully withstands the inclusion of water in the PrOx stream and presents good results in terms of CO elimination. However to achieve a good selectivity toward CO2 formation properly adjusting of the reaction parameters, such as oxygen concentration and space velocity is needed. Within the whole screened series the Cu-containing catalyst can be considered as the most interesting alternative for H2 clean-up applications

Boosting the activity of a Au/CeO2/Al2O3 catalysts for the WGS reaction

Herein a strategy to design highly efficient Au/CeO2/Al2O3 based WGS catalysts is proposed. The inclusion of transition metals, namely Fe, Cu and Zn as CeO2 dopant is considered. All the promoters successfully increased the WGS performance of the undoped sample. The activity improvement can be correlated to structural and/or redox features induced by the dopants. The comparative characterization of the doped samples by means of XRD, Raman spectroscopy and OSC evaluation permits an accurate understanding of the boosted WGS activity arising from the Ce-promoter interaction. This study establishes distinction among both, structural and redox sources of promotion and provides a useful strategy to develop highly active Au/CeO2 based catalysts for the WGS reaction

Low Temperature CO oxidation on multicomponent gold based systems

In this work the development of gold catalysts, essentially based on γ-alumina with small superficial fraction of Ce-Fe mixed oxides as support for the low temperature CO oxidation is proposed. Characterization results obtained by means of TEM, OSC, XPS, UV-Vis spectroscopy and H2-TPR are employed to correlate the activity data with the catalysts composition. The bare γ-alumina supported gold catalyst demonstrates the poorest activity within the series. The addition of CeO2 or FeOX improves the catalytic performance, especially observed for the CeO2-FeOx mixed oxide doped samples. This enhanced CO oxidation activity was related to the Ce-Fe interaction producing materials with promoted redox properties and therefore oxidation activity