The reciprocal connections between primary motor (M1) and primary somatosensory cortices (S1) are hypothesized to play a crucial role in the ability to update motor plans in response to changes in the sensory periphery. These interactions provide M1 with information about the sensory environment that in turn signals S1 with anticipatory knowledge of ongoing motor plans. In order to examine the synaptic basis of sensorimotor feedforward (S1-M1) and feedback (M1-S1) connections directly, we utilized whole-cell recordings in slices that preserve these reciprocal sensorimotor connections. Our findings indicate that these regions are connected via direct monosynaptic connections in both directions. Larger magnitude responses were observed in the feedforward direction (S1-M1), while the feedback (M1-S1) responses occurred at shorter latencies. The morphology as well as the intrinsic firing properties of the neurons in these pathways indicates that both excitatory and inhibitory neurons are targeted. Differences in synaptic physiology suggest that there exist specializations within the sensorimotor pathway that may allow for the rapid updating of sensory-motor processing within the cortex in response to changes in the sensory periphery.
The synthesis of metal-free graphene-based photocatalysts has received great attention recently due to their expected contributions to the development of solar-based hydrogen generation via water-splitting in a low cost and ecological manner. In this work, a new method for the generation of nitrogen-doped graphene-based powder employing an
The United Nations established 17 Sustainable Development Goals (SDGs), and the fulfillment of the 7th, defined as “Ensure access to affordable, reliable, sustainable, and modern energy for all”, requires energy industry transitions and digital transformations, which implies that diverse stakeholders need to move fast to allow the growth of more flexible power systems. This paper contains the case report that addresses the commercial digital transformation process developed at AES Colombia, through the implementation of a modern platform based on specialized applications that use Industry 4.0 tools. The Chivor hydropower project, a 1000-MW powerplant that covers 6% of Colombia’s demand, which is owned by AES Colombia and constitutes its primary asset, is first described. Then, a description of Colombia’s complex market (energy matrix, trading and dispatch mechanisms, and future projects) is presented. Then, the methodology followed for the digital transformation process using modern tools is described. The project, conceived as a broad framework, comprises applications for the management of hydrological, operational, and market information, commercial information systems and platforms to facilitate consultation and analysis by different users. Such an innovative project in the Latin American context has been developed in order reduce risks and to contribute to a sustainable energy supply for the future.
Bipyridinium salts, commonly known as viologens, are π-acceptor molecules that strongly interact with π-donor compounds, such as porphyrins or amino acids, leading their self-assembling. These properties have promoted us to functionalize polysilicon microparticles with bipyridinium salts for the encapsulation and release of π-donor compounds such as catecholamines and indolamines. In this work, the synthesis and characterization of four gemini-type amphiphilic bipyridinium salts (1·4PF6–4·4PF6), and their immobilization either non-covalently or covalently on polysilicon surfaces and microparticles have been achieved. More importantly, they act as hosts for the subsequent incorporation of π-donor neurotransmitters such as dopamine, serotonin, adrenaline or noradrenaline. Ultraviolet-visible absorption and fluorescence spectroscopies and high-performance liquid chromatography were used to detect the formation of the complex in solution. The immobilization of bipyridinium salts and neurotransmitter incorporation on polysilicon surfaces was corroborated by contact angle measurements. The reduction in the bipyridinium moiety and the subsequent release of the neurotransmitter was achieved using ascorbic acid, or Vitamin C, as a triggering agent. Quantification of neurotransmitter encapsulated and released from the microparticles was performed using high-performance liquid chromatography. The cytotoxicity and genotoxicity studies of the bipyridinium salt 1·4PF6, which was selected for the non-covalent functionalization of the microparticles, demonstrated its low toxicity in the mouse fibroblast cell line (3T3/NIH), the human liver carcinoma cell line (HepG2) and the human epithelial colorectal adenocarcinoma cell line (Caco-2).
ResumenSe muestran los resultados experimentales de la síntesis de cetales de glicerina para su uso como aditivos que mejoren las propiedades de flujo a baja temperatura de un biodiesel de aceite de palma. Se evalúo su producción empleando catalizadores heterogéneos ácidos del tipo resinas de poliestireno sulfonadas (Amberlyst 15, Dowex 50X2) y homogéneos (ácido sulfúrico y ptoluensulfónico). Se analizó el efecto del cetal en las propiedades de flujo a baja temperatura al mezclarse en diferentes proporciones con el biodiesel, evaluando el punto de nube y el punto de fluidez a cada mezcla. Mediante calorimetría diferencial de barrido se evaluó los puntos de cristalización de las mezclas del aditivo con el biodiesel y se comparó con el correspondiente para el biodiesel puro. Se encontró que con el empleo de catalizadores heterogéneos se pueden obtener conversiones por encima del 90% y la adición de los cetales al biodiesel puede lograr disminuciones de hasta 6ºC en el punto de nube y fluidez. También, los termogramas de enfriamiento mostraron una disminución efectiva en las temperaturas de cristalización. Palabras clave: glicerina, cetales, biodiesel, modificaciones químicas, catálisis heterogénea Synthesis of Additives for Biodiesel through Chemical Modifications of Glycerol AbstractIn this work the results of the synthesis of glycerin ketals for application as additives to improve the cold flow properties of palm oil biodiesel employing heterogeneous and homogeneous catalyst are shown. Sulfonated polystyrene resins (Amberlyst 15, Dowex 50X2) were employed as heterogeneous catalysts, and homogenous catalysts (sulfuric acid and p-toluensulfonic acid). The effect of amount of ketals on cold flow properties of biodiesel was analyzed through determination of cloud point and pour point for each blend. Through differential scanning calorimetry crystallization points of additive-biodiesel blends were evaluated and compared with those of unmodified biodiesel. It was found that with the use of heterogeneous catalysts, conversions of glycerin above 90% were obtained. Also, the addition of ketals to biodiesel allows reductions up to 6ºC in the cloud point and pour point. Also, cooling thermograms showed effective reduction in crystallization temperatures.
An overview of the research activities and on-going multiple projects at Delft University of Technology aimed at the development of Gasifier–Solid Oxide Fuel Cell (SOFC) based power plants are presented. Biosyngas generated in gasifiers consists of a mixture of carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), hydrogen (H2), nitrogen (N2), water vapor (H2O), and minor impurities. Biosyngas can be a good fuel for SOFCs provided that the gas is sufficiently cleaned. Influence of biosyngas compositions and biomass-derived contaminants on SOFCs is presented and the removal of potential contaminants such as tar, particulates, H2S, HCl, and alkali compounds from biosyngas is discussed. It appears that the gasification product gas can be cleaned to meet the requirements of SOFCs using currently known gas cleaning methods. Additionally, a brief discussion on the achievable system efficiencies with gasifier–SOFC systems is presented. Innovative applications of the gasifier-SOFC systems being developed at Delft, such as advanced gasifier–SOFC systems for toilet development, are also presented.
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