Considering the alarming scenario of climate change, CO2 hydrogenation to methanol is considered a key process for phasing out fossil fuels by means of CO2 utilization. In this context, MoS2 ...catalysts have recently shown to be promising catalysts for this reaction, especially in the presence of abundant basal-plane sulfur vacancies and due to synergistic mechanisms with other phases. In this work, Mn-promoted MoS2 prepared by a hydrothermal method presents considerable selectivity for CO2 hydrogenation to methanol in comparison with pure MoS2 and other promoters such as K and Co. Interestingly, if CO is used as a carbon source for the reaction, methanol production is remarkably lower, which suggests the absence of a CO intermediate during CO2 hydrogenation to methanol. After optimization of synthesis parameters, a methanol selectivity of 64% is achieved at a CO2 conversion of 2.8% under 180 °C. According to material characterization by X-ray Diffraction and X-ray Absorption, the Mn promoter is present mainly in the form of MnO and MnCO3 phases, with the latter undergoing convertion to MnO upon H2 pretreatment. However, following exposure to reaction conditions, X-ray photoelectron spectroscopy suggests that higher oxidation states of Mn may be present at the surface, suggesting that the improved catalytic activity for CO2 hydrogenation to methanol arises from a synergy between MoS2 and MnOx at the catalyst surface.
The conversion of CO2 into CO is an important step in CO2 utilization to achieve clean fuels and value‐added chemicals. Herein, we explored the pyrolysis of zeolitic imidazolate framework‐8 (ZIF‐8) ...loaded with different amounts of Ni2+ to obtain Ni−Zn carbide (Ni3ZnC) embedded in N‐doped carbon. Ni is present in the intermetallic compound, while Zn excess remains on the N‐doped carbon. The Ni3ZnC phase catalyzes the selective hydrogenation of CO2 into CO via the reverse water gas shift reaction, reaching 100 % CO selectivity at ∼30 % CO2 conversion at 450 °C and atmosphere pressure (CO2 : H2=1 : 4, GHSV=30000 mL gcat−1 h−1). The methanation reaction of CO2/CO, which is usually favored over Ni catalysts, is suppressed. The selectivity to CO at the expense of CH4 is related to the stability of chemisorbed CO in the Ni3ZnC surface, which is lower compared to Ni surfaces. The Ni3ZnC@NC catalyst is selective towards CO over a wide range of conditions, including high pressure, that is usually required for the conversion of CO to hydrocarbons and alcohols via the Fisher‐Tropsch synthesis (FTS) process. Contrarily, a classical Ni/SiO2 catalyst prepared by impregnation produces CH4 under high pressure.
The Ni3ZnC phase catalyzes the selective hydrogenation of CO2 into CO via the reverse water gas shift (RWGS) reaction, while the methanation reaction of CO2/CO, which is usually favored over Ni catalysts, was completely suppressed, even at high pressures. This finding opens the door for the integration of RWGS/Fisher‐Tropsch synthesis (FTS) tandem process to achieve the conversion of CO2‐to‐liquids.
Heat-processed diets contain high amounts of advanced glycation end products (AGEs). Here we explore the impact of an AGE-enriched diet on markers of metabolic and inflammatory disorders as well as ...on gut microbiota composition and plasma proteins glycosylation pattern. C57BL/6 mice were allocated into control diet (CD,
= 15) and AGE-enriched diet (AGE-D,
= 15) for 22 weeks. AGE-D was prepared replacing casein by methylglyoxal hydroimidazolone-modified casein. AGE-D evoked increased insulin and a significant reduction of GIP/GLP-1 incretins and ghrelin plasma levels, altered glucose tolerance, and impaired insulin signaling transduction in the skeletal muscle. Moreover, AGE-D modified the systemic glycosylation profile, as analyzed by lectin microarray, and increased Nε-carboxymethyllysine immunoreactivity and AGEs receptor levels in ileum and submandibular glands. These effects were associated to increased systemic levels of cytokines and impaired gut microbial composition and homeostasis. Significant correlations were recorded between changes in bacterial population and in incretins and inflammatory markers levels. Overall, our data indicates that chronic exposure to dietary AGEs lead to a significant unbalance in incretins axis, markers of metabolic inflammation, and a reshape of both the intestinal microbiota and plasma protein glycosylation profile, suggesting intriguing pathological mechanisms underlying AGEs-induced metabolic derangements.
We investigated whether isotopic niche partitioning could mediate the coexistence between native (Hoplias sp. B) and non‐native (Hoplias mbigua) trahira in a Neotropical floodplain. We hypothesised ...that during the dry season both species inhabit isolated sites (i.e. lakes) and thus rely on distinct food resources to sustain their coexistence. We found evidence of trophic segregation among native and non‐native freshwater fish in the Upper Paraná River, Brazil. Even though both species rely on the same primary littoral carbon sources and present similar trophic diversity, trophic segregation was attained through larger niche amplitude and smaller isotopic niche width for the non‐native fish. Three decades after initial invasion, non‐native Hoplias have distinct foraging behaviour and do not compete for trophic resources with native trahira; this is likely due to morpho‐anatomical differences. Limited morphological similarity between these congeneric species might be the strongest factor contributing to their coexistence in the Paraná River floodplain during the dry season.
Sugarcane, one of the world’s major crops, is used to produce sucrose and biofuel. Before harvesting, sugarcane is burned to facilitate manual cutting, generating ashes that may reach water bodies ...and cause the death of aquatic organisms. While studies have addressed the lethal effects of sugarcane ashes (SCA) on different fishes, little is known about the effects of sublethal SCA concentration on aquatic organisms. In this study, we evaluated the behaviour of a piscivorous (
Hoplerythrinus unitaeniatus
) and an invertivorous (
Moenkhausia forestii
) fish species, after a short-term (24 h) exposure to a sublethal concentration of SCA (0.8 g L
−1
). We hypothesized that the outcomes of predator–prey interaction would change when the players are subjected to sublethal SCA concentration. Our findings revealed that neither the behaviours of predator and prey fish species nor the outcome of their interactions was changed by the exposure to sublethal SCA concentrations, suggesting that their behavioural traits were not particularly sensitive to SCA. However, we emphasize that (i) other predatory and anti-predator behavioural traits could be affected by SCA even at under 0.8 g L
−1
concentration and (ii) higher concentrations of SCA and/or long-term exposure may trigger profound changes in the behaviour of predator and prey fish species. Our findings are worrisome because there are new public policies to expand sugarcane production in Brazil, with the possibility of continuing burning sugarcane crops across the country. This will increase the input of SCA into aquatic systems, generating more prominent and pervasive negative impacts than those evaluated in this study.
Brazil's vegetation ravage may be encouraged by law Alves, Gustavo H. Zaia; Tófoli, Raffael M.; Rodrigues-Filho, Jorge L. ...
Biodiversity and conservation,
03/2020, Letnik:
29, Številka:
3
Journal Article
Background and Aims
X‐linked Charcot–Marie–Tooth disease type 6 (CMTX6) is an extremely rare condition associated with mutations in the PDK3 gene. To date, only three families from different ...countries have been reported (Australia, South Korea, and Germany). In this study, we sought to provide a comprehensive clinical and electrophysiological characterization of two Brazilian families.
Methods
We conducted comprehensive clinical assessments, extensive electrophysiological evaluations, and performed whole‐exome sequencing in the probands to investigate the genetic basis of the disease.
Results
Males in the family carrying the Arg162His mutation displayed early‐onset motor and/or sensory axonal neuropathy, absence of tendon jerks, pes cavus, and frequently reported pain. Females in the same family exhibited a milder phenotype of the disease with later onset and some remained asymptomatic into their 50s. In the unrelated family with a single affected male, the clinical presentation was characterized by severe progressive sensorimotor polyneuropathy accompanied by neuropathic pain.
Interpretation
We report two Brazilian families with CMTX6 including one harboring a previously unpublished variant in the PDK3 gene, which co‐segregates with the disease as expected in a X‐linked disease. Notably, the clinical presentations across the five families with available descriptions, including our study, share striking similarities. Furthermore, the proximity of the three reported mutations suggests potential functional similarities and common underlying mechanisms. This study contributes to the growing knowledge of CMTX6 and underscores the importance of international collaborations in studying rare genetic disorders.
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