High-loading, ultrafine Ni nanoparticles dispersed on porous hollow carbon nanospheres for fast (de)hydrogenation kinetics of MgH_(2)

Magnesium hydride(MgH2) is one of the most promising hydrogen storage materials for practical application due to its favorable reversibility, low cost and environmental benign;however, it suffers from high dehydrogenation temperature and slow sorption kinetics.Exploring proper catalysts with high and sustainable activity is extremely desired for substantially improving the hydrogen storage properties of MgH2. In this work, a composite catalyst with high-loading of ultrafine Ni nanoparticles(NPs) uniformly dispersed on porous hollow carbon nanospheres is developed, which shows superior catalytic activity towards the de-/hydrogenation of MgH2. With an addition of 5wt% of the composite, which contains 90 wt% Ni NPs, the onset and peak dehydrogenation temperatures of MgH2are lowered to 190 and 242 ℃, respectively. 6.2 wt% H2is rapidly released within 30 min at 250 ℃. The amount of H2that the dehydrogenation product can absorb at a low temperature of 150 ℃ in only 250 s is very close to the initial dehydrogenation value. A dehydrogenation capacity of 6.4wt% remains after 50 cycles at a moderate cyclic regime, corresponding to a capacity retention of 94.1%. The Ni NPs are highly active,reacting with MgH2and forming nanosized Mg2Ni/Mg2NiH4. They act as catalysts during hydrogen sorption cycling, and maintain a high dispersibility with the help of the dispersive role of the carbon substrate, leading to sustainably catalytic activity. The present work provides new insight into designing stable and highly active catalysts for promoting the(de)hydrogenation kinetics of MgH2.

Whole transcriptome analysis of RNA expression profiles reveals the potential regulating action of long noncoding RNA in lactating cows fed a high concentrate diet

Subacute ruminal acidosis(SARA)is a common metabolic disease in the dairy farming industry which is usually caused by an excessive amount of high concentrate diet.SARA not only threatens animal welfare but also leads to economic losses in the farming industry.The liver plays an important role in the distribution of nutritional substances and metabolism;however,a high concentrate diet can cause hepatic metabolic disorders and liver injury.Recently,noncoding RNA has been considered as a critical regulator of hepatic disease,however,its role in the bovine liver is limited.In this study,12 mid-lactating dairy cows were randomly assigned to a control(CON)group(40% concentrate of dry matter,n=6)and a SARA group(60% concentrate of dry matter,n=6).After 21 d of treatment,all cows were sacrificed,and liver tissue samples were collected.Three dairy cows were randomly selected from the CON and SARA groups respectively to perform whole transcriptome analysis.More than 20,000 messenger RNA(mRNA),10,000 long noncoding RNA(lncRNA),3,500 circular RNA(circRNA)and 1,000 micro RNA(miRNA)were identified.Furthermore,43 mRNA,121 lncRNA and 3 miRNA were differentially expressed,whereas no obvious differentially expressed circRNA were detected between the 2 groups.Gene Ontology(GO)annotation revealed that the differentially expressed genes were mainly enriched in oxidoreductase activity,stress,metabolism,the immune response,cell apoptosis,and cell proliferation.Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analysis showed that the deferentially expressed genes were highly enriched in the phosphatidylinositol 3 kinase(PI3) K-serine/threonine kinase(AKT)signaling pathway(P<0.05).According to KEGG pathway analysis,the differentially expressed lncRNA(DElncRNA)target genes were mainly related to proteasomes,peroxisomes,and the hypoxia-inducible factor-1 signaling pathway(P<0.005).Further bioinformatics and integrative analyses revealed that the lncRNA were strongly correlated with mRNA;therefore,it is reasonable to speculate that lncRNA potentially play important roles in the liver dysfunction induced by SARA.Our study provides a valuable resource for future investigations on the mechanisms of SARA to facilitate an understanding of the importance of lncRNA,and offer functional RNA information.

DEM simulations of tote blenders for enhanced axial mixing efficiency

The mixing performance of a multi-bladed tote blender is investigated using a graphics processing unit-based discrete element method program.The positioning,dimensions,and applicability of the baffles are systematically studied according to the axial mixing efficiency.The results indicate that the novel inclined multi-bladed baffles can break the symmetrical axial granular flow and introduce a more efficient convective flow into the granular mixing in the axial direction of the tote blender.Owing to the joint effects of convective mixing and asymmetrical granular flow,the axial mixing efficiency is increased by a factor of nearly 20.More importantly,the novel baffle placement approach exhibits excellent applicability to different operating conditions,particle shapes,and blender sizes.Additionally,the inclined baffles can prevent the segregation caused by shape discrepancies and improve the mixing homogeneity in the steady state.The novel baffle design is promising for applications in more complex industrial blenders for achieving a high axial mixing efficiency.