Comparison of the Influence of Oxygen Groups Introduced by Graphene Oxide on the Activity of Carbon Felt in Vanadium and Anthraquinone Flow Batteries.

An increasing number of studies focus on organic flow batteries (OFBs) as possible substitutes for the vanadium flow battery (VFB), featuring anthraquinone derivatives, such as anthraquinone-2,7-disulfonic acid (2,7-AQDS). VFBs have been postulated as a promising energy storage technology. However, the fluctuating cost of vanadium minerals and risky supply chains have hampered their implementation, while OFBs could be prepared from renewable raw materials. A critical component of flow batteries is the electrode material, which can determine the power density and energy efficiency. Yet, and in contrast to VFBs, studies on electrodes tailored for OFBs are scarce. Hence, in this work, we propose the modification of commercial carbon felts with reduced graphene oxide (rGO) and poly(ethylene glycol) for the 2,7-AQDS redox couple and to preliminarily assess its effects on the efficiency of a 2,7-AQDS/ferrocyanide flow battery. Results are compared to those of a VFB to evaluate if the benefits of the modification are transferable to OFBs. The modification of carbon felts with surface oxygen groups introduced by the presence of rGO enhanced both its hydrophilicity and surface area, favoring the catalytic activity toward VFB and OFB reactions. The results are promising, given the improved behavior of the modified electrodes. Parallels are established between the electrodes of both FB technologies.

TP53INP2-dependent activation of muscle autophagy ameliorates sarcopenia and promotes healthy aging.

Sarcopenia is a major contributor to disability in older adults, and thus, it is key to elucidate the mechanisms underlying its development. Increasing evidence suggests that impaired macroautophagy/autophagy contributes to the development of sarcopenia. However, the mechanisms leading to reduced autophagy during aging remain largely unexplored, and whether autophagy activation protects from sarcopenia has not been fully addressed. Here we show that the autophagy regulator TP53INP2/TRP53INP2 is decreased during aging in mouse and human skeletal muscle. Importantly, chronic activation of autophagy by muscle-specific overexpression of TRP53INP2 prevents sarcopenia and the decline of muscle function in mice. Acute re-expression of TRP53INP2 in aged mice also improves muscle atrophy, enhances mitophagy, and reduces ROS production. In humans, high levels of TP53INP2 in muscle are associated with increased muscle strength and healthy aging. Our findings highlight the relevance of an active muscle autophagy in the maintenance of muscle mass and prevention of sarcopenia.Abbreviation: ATG7: autophagy related 7; BMI: body mass index; EIF4EBP1: eukaryotic translation initiation factor 4E binding protein 1; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; ROS: reactive oxygen species; TP53INP2: tumor protein p53 inducible nuclear protein 2; WT: wild type.

Mitofusin-2 induced by exercise modifies lipid droplet-mitochondria communication, promoting fatty acid oxidation in male mice with NAFLD.

BACKGROUND AND AIM: The excessive accumulation of lipid droplets (LDs) is a defining characteristic of nonalcoholic fatty liver disease (NAFLD). The interaction between LDs and mitochondria is functionally important for lipid metabolism homeostasis. Exercise improves NAFLD, but it is not known if it has an effect on hepatic LD-mitochondria interactions. Here, we investigated the influence of exercise on LD-mitochondria interactions and its significance in the context of NAFLD. APPROACH AND RESULTS: Mice were fed high-fat diet (HFD) or HFD-0.1 % methionine and choline-deficient diet (MCD) to emulate simple hepatic steatosis or non-alcoholic steatohepatitis, respectively. In both models, aerobic exercise decreased the size of LDs bound to mitochondria and the number of LD-mitochondria contacts. Analysis showed that the effects of exercise on HOMA-IR and liver triglyceride levels were independent of changes in body weight, and a positive correlation was observed between the number of LD-mitochondria contacts and NAFLD severity and with the lipid droplet size bound to mitochondria. Cellular fractionation studies revealed that ATP-coupled respiration and fatty acid oxidation (FAO) were greater in hepatic peridroplet mitochondria (PDM) from HFD-fed exercised mice than from equivalent sedentary mice. Finally, exercise increased FAO and mitofusin-2 abundance exclusively in PDM through a mechanism involving the curvature of mitochondrial membranes and the abundance of saturated lipids. Accordingly, hepatic mitofusin-2 ablation prevented exercise-induced FAO in PDM. CONCLUSIONS: This study demonstrates that aerobic exercise has beneficial effects in murine NAFLD models by lessening the interactions between hepatic LDs and mitochondria, and by decreasing LD size, correlating with a reduced severity of NAFLD. Additionally, aerobic exercise increases FAO in PDM and this process is reliant on Mfn-2 enrichment, which modifies LD-mitochondria communication.

Tailored Porous Carbon Xerogels for Fe-N-C Catalysts in Proton Exchange Membrane Fuel Cells.

Atomically dispersed Fe-N-C catalysts for the oxygen reduction reaction (ORR) have been synthesized with a template-free method using carbon xerogels (CXG) as a porous matrix. The porosity of the CXGs is easily tunable through slight variations in the synthesis procedure. In this work, CXGs are prepared by formaldehyde and resorcinol polymerization, modifying the pH during the process. Materials with a broad range of porous structures are obtained: from non-porous to micro-/meso-/macroporous materials. The porous properties of CXG have a direct effect on Fe-N-CXG activity against ORR in an acidic medium (0.5 M H2SO4). Macropores and wide mesopores are vital to favor the mass transport of reagents to the active sites available in the micropores, while narrower mesopores can generate additional tortuosity. The role of microporosity is investigated by comparing two Fe-N-C catalysts using the same CXG as the matrix but following a different Fe and N doping procedure. In one case, the carbonization of CXG occurs rapidly and simultaneously with Fe and N doping, whereas in the other case it proceeds slowly, under controlled conditions and before the doping process, resulting in the formation of more micropores and active sites and achieving higher activity in a three-electrode cell and a better durability during fuel cell measurements. This work proves the feasibility of the template-free method using CXG as a carbon matrix for Fe-N-C catalysts, with the novelty of the controlled porous properties of the carbon material and its effect on the catalytic activity of the Fe-N-C catalyst. Moreover, the results obtained highlight the importance of the carbon matrix's porous structure in influencing the activity of Fe-N-C catalysts against ORR.

Diagnóstico de la fertilidad de los suelos de cuatro municipios de Cundinamarca (Colombia) para la producción de plátano / Diagnostics of soil fertility in four municipalities of Cundinamarca (Colombia) employed for cooking banana production

RESUMEN Para lograr rendimientos óptimos en la producción de plátano, se debe tener en cuenta la disponibilidad de nutrientes en el suelo, para así ajustar planes de fertilización adecuados. Con el fin de contribuir al estudio de la fertilidad de suelos cultivados con plátano en el departamento de Cundinamarca-Colombia, se realizó una caracterización química de suelos, en cuatro de los principales municipios productores. Se visitaron 146 fincas, ubicadas en Viotá, La Vega, La Palma y Chaguaní, donde se tomaron muestras de suelo, para análisis químico. Los resultados obtenidos fueron sometidos a un análisis de frecuencias, correlación lineal de Pearson y componentes principales, realizando, finalmente, una comparación de medias entre los cuatro municipios. Se observaron niveles bajos de P, S y Mg, medios de K, Ca y B, así como altas concentraciones de Zn, que pueden llegar a ser tóxicas para el cultivo de plátano. Por otro lado, las variables se agruparon en cuatro componentes asociados a: la capa de cambio del suelo, la reacción del suelo, la salinidad y la relación entre el P y Zn. Suelos de los municipios de La Vega y La Palma no presentaron variación en la capa de cambio y la reacción del suelo, caso contrario al observado en suelos de Viotá y Chaguaní. Entre suelos de los municipios, se presentaron diferencias significativas para las propiedades materia orgánica, Ca y Mg, así como desbalances catiónicos y pH fuertemente ácidos.

ABSTRACT To achieve optimum yields in plantain production, appropriate fertilization plans must be adjusted, for which the availability of nutrients in the soil must be taken into account. In order to contribute to the study of the fertility of soils cultivated with cooking banana in the province of Cundinamarca - Colombia, a chemical characterization of soils was carried out in four of the main producing municipalities. 146 farms located in Viotá, La Vega, La Palma and Chaguaní, were visited, and soil samples were taken for chemical analysis. The results obtained were subjected to a frequency analysis, Pearson's linear correlation and main components; finally making a comparison of means between the four municipalities. Low levels of P, S and Mg, medium of K, Ca and B were observed, as well as high concentrations of Zn that can be toxic for the plantain crop. On the other hand, the variables were grouped into four components associated with: the soil change layer, the soil reaction, the salinity and the relationship between P and Zn. Soils of the municipalities of La Vega and La Palma did not show variation in the change layer and soil reaction, contrary to that observed in Viotá and Chaguaní soils. Among the soils of the municipalities, there were significant differences for the properties of organic matter, Ca and Mg as well as cationic imbalances and strongly acidic pH.