Midnight-sun-induced natural gas conversion

The 11th NGCS meeting took place between 5th and 9th of June 2016, and was hosted in Tromsø/Norway. The latest developments from academic and industrial perspectives were discussed and presented in (1) Production of Synthesis Gas, (2) Synthesis Gas to Fuels and Chemicals, (3) Direct Conversion of Methane, (4) Conversion of Light Paraffins, (5) Natural Gas in Energy Conversion, and (6) Techno-Economic Aspects. Along with the social events and the post-symposium excursions, this NGCS meeting was a memorable symposium for all participants

Capturing metal-support interactions in situ during the reduction of a Re promoted Co/γ-Al₂O₃ catalyst

The diffusion of Co2+ cations into the γ-Al2O3 support is probed during the reduction of a Re/Co/γ-Al2O3 catalyst by in situ by synchrotron X-ray powder diffraction resulting in the expansion of its crystal lattice.</p

Impaired leptin signaling causes subfertility in female zebrafish

Reproduction is an energetically costly event across vertebrates and tightly linked to nutritional status and en-ergy reserves. In mammals, the hormone leptin is considered as a link between energy homeostasis and repro-duction. However, its role in fish reproduction is still unclear. In this study, we investigated the possible role of leptin in the regulation of reproduction in zebrafish, using a loss of function leptin receptor (lepr) strain. Impaired leptin signaling resulted in severe reproductive deficiencies in female zebrafish. lepr mutant females laid significantly fewer eggs, with low fertilization rates compared to wild-type females. Folliculogenesis was not affected, but oocyte maturation and ovulation were disrupted in lepr mutants. Interestingly, the expression of luteinizing hormone beta (lhb) in the pituitary was significantly lower in mutant females. Analysis of candidate genes in the ovaries and isolated fully grown follicles revealed differential expression of genes involved in ste-roidogenesis, oocyte maturation and ovulation in the mutants, which are known to be regulated by LH signaling. Moreover, subfertility in lepr mutants could be partially restored by administration of human chorionic gonad-otropin. In conclusion, our results show that leptin deficiency does not affect early stages of follicular devel-opment, but leptin might be essential in later steps, such as in oocyte maturation and ovulation. To our knowledge, this is the first time that leptin is associated to reproductive deficiencies in zebrafish.Peer reviewe

Transcriptional study reveals a potential leptin-dependent gene regulatory network in zebrafish brain

The signal mediated by leptin hormone and its receptor is a major regulator of body weight, food intake and metabolism. In mammals and many teleost fish species, leptin has an anorexigenic role and inhibits food intake by influencing the appetite centres in the hypothalamus. However, the regulatory connections between leptin and downstream genes mediating its appetite-regulating effects are still not fully explored in teleost fish. In this study, we used a loss of function leptin receptor zebrafish mutant and real-time quantitative PCR to assess brain expression patterns of several previously identified anorexigenic genes downstream of leptin signal under different feeding conditions (normal feeding, 7-day fasting, 2 and 6-h refeeding). These downstream factors include members of cart genes, crhb and gnrh2, as well as selected genes co-expressed with them based on a zebrafish co-expression database. Here, we found a potential gene expression network (GRN) comprising the abovementioned genes by a stepwise approach of identifying co-expression modules and predicting their upstream regulators. Among the transcription factors (TFs) predicted as potential upstream regulators of this GRN, we found expression pattern of sp3a to be correlated with transcriptional changes of the downstream gene network. Interestingly, the expression and transcriptional activity of Sp3 orthologous gene in mammals have already been implicated to be under the influence of leptin signal. These findings suggest a potentially conserved regulatory connection between leptin and sp3a, which is predicted to act as a transcriptional driver of a downstream gene network in the zebrafish brain.Peer reviewe

Appetite regulating genes in zebrafish gut; a gene expression study

Peer reviewe

In-situ X-Ray Absorption Near Edge Structure Spectroscopy of a Solid Catalyst using a Laboratory-Based Set-up

An in-situ laboratory-based X-ray Absorption Near Edge Structure (XANES) Spectroscopy set-up is presented, which allows performing long-term experiments on a solid catalyst at relevant reaction conditions of temperature and pressure. Complementary to research performed at synchrotron radiation facilities the approach is showcased for a Co/TiO2 Fischer-Tropsch Synthesis (FTS) catalyst. Supported cobalt metal nanoparticles next to a (very small) fraction of cobalt(II) titanate, which is an inactive phase for FTS, were detected, with no signs of re-oxidation of the supported cobalt metal nanoparticles during FTS at 523 K, 5 bar and 200 h, indicating that cobalt metal is maintained as the main active phase during FTS.Peer reviewe

Sunlight-assisted hydrogenation of CO2 into ethanol and C2+ hydrocarbons by sodium-promoted Co@C nanocomposites

[EN] The hydrogenation of CO2 into hydrocarbons promoted by the action of sunlight has been studied on Co nanoparticles covered by thin carbon layers. In particular, nearly 100% selectivity to hydrocarbons is obtained with increased selectivities towards C2 + hydrocarbons and alcohols (mainly ethanol) when using nanostructured materials comprising metallic cobalt nanoparticles, carbon layers, and sodium as promoter (NaCo@C). In the contrary, larger amount of CH4 and lower selectivity to C2 + hydrocarbons and alcohols were obtained in the conventional thermal catalytic process. When using Co@C nanoparticles in the absence of Na or bare Co3O4 as catalyst, methane is essentially the main product (selectivity > 96%). Control experiments in the presence of methanol as a hole scavenger suggest the role of light in generating charges by photon absorption as promoting factor. The reaction mechanism for photoassisted CO2 hydrogenation on the Co-based catalysts was investigated by near ambient-pressure X-ray photoelectron (AP-XPS) and in situ Raman spectroscopies, which provided information on the role of light and Na promoter in the modulation of product distribution for CO2 hydrogenation. Spectroscopic studies suggested that surface CO2 dissociation to CO, the stabilization of CO adsorbed on the surface of Na-Co@C catalyst and the easy desorption of reaction products is a key step for photothermal CO2 hydrogenation to ethanol and C2 + hydrocarbons.L.L. thanks ITQ for providing a contract. A.V.P. thanks the Spanish Government (Agencia Estatal de Investigacion) and the European Union (European Regional Development Fund) for a grant for young researchers (CTQ2015-74138-JIN, AEI/FEDER/UE). J.C. thanks the Spanish Government-MINECO for a "Severo Ochoa" grant (BES-2015-075748). The AP-XPS experiments were performed at NAPP endstation of CIRCE beamline at ALBA Synchrotron with the collaboration of ALBA staff. The authors also thank the Microscopy Service of UPV for kind help on FESEM, TEM and STEM measurements. Financial supports from the Spanish Government-MINECO through "Severo Ochoa" (SEV-2016-0683) program are also gratefully acknowledged.Liu, L.; Puga, AV.; Cored-Bandrés, J.; Concepción Heydorn, P.; Pérez-Dieste, V.; García Gómez, H.; Corma Canós, A. (2018). Sunlight-assisted hydrogenation of CO2 into ethanol and C2+ hydrocarbons by sodium-promoted Co@C nanocomposites. Applied Catalysis B Environmental. 235:186-196. https://doi.org/10.1016/j.apcatb.2018.04.060S18619623