Regulating oxygen vacancies by Zn atom doping to anchor and disperse promoter Ba on MgO support to improve Ru-based catalysts activity for ammonia synthesis.

In heterogeneous catalysis, surface defects are widely regarded as an effective means to enhance the catalytic performance of catalysts. In this study, the oxygen vacancy-rich Mg(1-X)ZnXO solid solution support was successfully prepared by doping a small amount of Zn into MgO nanocrystals. Based on this support, Ru/Ba-Mg(1-X)ZnXO catalyst for ammonia synthesis was prepared. Characterization using TEM, EPR, XPS, and DFT calculations confirmed the successful substitution of Zn atoms for Mg atoms leading to the formation of more oxygen vacancies (OVs). N2-TPD, SEM and TEM analyses revealed that a small amount of Zn had minimal influence on the surface morphology and the size of Ru nanoparticles. The abundance of OVs in the support was identified as the primary factor enhancing the catalytic activity. XPS, H2-TPD and kinetics experiment studies further elucidated the mechanism by which OVs promote the reaction, with OVs serving as an anchor point for the promoter Ba on the MgO support and promoted the dispersion of Ba. This anchoring effect not only enhanced the electron density on Ru, favoring the dissociation of the N[triple bond, length as m-dash]N bond, but also mitigated hydrogen poisoning. As a result,the ammonia synthesis rate reached 1.73 mmol g-1 h-1. Furthermore, the CO2-TPD and H2-TPR analyses indicated that Zn doping effectively promotes the metal-support interaction (MSI) and surface alkalinity. The findings of this study offers valuable insights for the design of defective modified catalyst supports.

Phytochemical wedelolactone reverses obesity by prompting adipose browning through SIRT1/AMPK/ PPARα pathway via targeting nicotinamide N-methyltransferase.

BACKGROUND: Obesity is the cause of multiple metabolic disorders, and its incidence has been rapidly increasing worldwide. It develops when energy intake exceeds energy expenditure (EE). Wedelolactone (WDL) is a naturally isolated compound from Eclipta prostrata L. and possesses many pharmacological activities. However, little is known about the effect of WDL on obesity and EE. PURPOSE: The present study aimed to investigate the effect of WDL on obesity and EE in diet-induced obese (DIO) mice and its underlying mechanism. METHODS: Obese mice were induced by high fat diet. The effects of WDL on obese mice were assessed by examining body weight, fat mass, EE, glucose tolerance, and hepatic and kidney injury. 3T3-L1 cells were differentiated into mature adipocytes and incubated with WDL in vitro. Immunohistochemistry, western blotting, and real-time PCR were used to assess adipose browning. The inhibitory efficiency of WDL on nicotinamide N-methyltransferase (NNMT) was evaluated using a fluorescence assay. RESULTS: WDL reduced fat mass, suppressed body weight gain, and improved obesity-related metabolic disorders in DIO mice. WDL treatment promoted adipose browning and enhanced EE in both DIO mice and 3T3-L1 cells. These effects were eliminated in AMPK antagonized or PPARα knockdown cells and in PPARα-/- mice. Furthermore, we identified the target of WDL to be NNMT, an appealing target for regulating energy metabolism. WDL inhibited NNMT with an extremely low IC50 of 0.03 µM. Inhibition of NNMT and activation of SIRT1/AMPK/PPARα explains how WDL reverses obesity by prompting adipose browning. CONCLUSION: Our findings demonstrate the novel effects of WDL in promoting adipose browning, enhancing EE and attenuating obesity and uncover the underlying mechanism, which includes inhibition of NNMT and subsequently activation of SIRT1/AMPK/PPARα in response to WDL. WDL could be further developed as a therapeutic agent for treating obesity and related metabolic diseases.

Highly sensitive humidity-driven actuators based on metal-organic frameworks incorporating thermoplastic polyurethane with gradient polymer distribution.

Ambient humidity plays an important role in the fields of industrial and agricultural production, food and drug storage, climate monitoring, and maintenance of precision instruments. To sense and control humidity, humidity-responsive actuators that mimick humidity responsive behavior existing in nature, have attracted intense attention. The most common and important class of humidity actuators is active bilayer structures. However, such bilayer structures generally show weak interfacial adhesion, tending to delaminate during frequent bending and restoration cycles. In this work, to address this problem, a novel monolayer humidity-driven actuator with no adhesive issue is developed by integrating the swellable metal-organic frameworks (MIL-88A) into thermoplastic polyurethane films. The proposed actuators display excellent humidity response that under the conditions of relative humidity simulated with saturated salt solution, the MIL-88A/polyurethane composite films show good self-folding response and stability for recycling use. In addition, a deep insight into the self-folding of the composite films is also provided and a new response mechanism is proposed. In this case, the results show that both the preparation method and response properties of the humidity actuators are improved. Therefore, it suggests a new promising way to develop and design flexible humidity actuators.

Immunomodulatory effect of oleoylethanolamide in dendritic cells via TRPV1/AMPK activation.

Oleoylethanolamide (OEA) is an endogenous lipid mediator involved in the control of feeding, body weight, and energy metabolism. However, whether OEA modulates maturation of dendritic cells (DCs) has never been addressed. Hence, we evaluated the effect of OEA on DCs maturation in bone marrow-derived DCs (BMDCs) in four aspects: (a) Cell surface markers were determined using flow cytometric analysis; (b) cell mobile ability was testified with the transwell assay; (c) stimulation of T cells proliferation was performed in a coculture system; and (d) cytokine production was measured using polymerase chain reaction (PCR). The result showed that, in mature BMDCs induced by lipopolysaccharides (LPS), the OEA treatment decreased expressions of cell surface markers, reduced cell migration, diminished the proliferation of cocultured T cells, and regulated cytokine production of BMDCs, indicating the modulatory effect of OEA on DCs maturation. Furthermore, to explore the underlying mechanism of the immunomodulatory effect of OEA, we used antagonists of transient receptor potential vanilloid-1 (TRPV1) and AMP-activated protein kinase (AMPK), determined the protein expressions of TRPV1/AMPK and Toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB) using western blot, and measured the intracellular calcium concentration using calcium imaging. The result illustrated that OEA downregulated TLR4/NF-κB, the classical pathway leading to DCs maturation induced by LPS, through the activation of TRPV1 and AMPK. Collectively, the present study suggests that OEA suppresses DCs maturation through the activation of TRPV1/AMPK. These findings increase our understanding of this endogenous lipid OEA.

The effect of Fe2O3 crystal phases on CO2 hydrogenation.

The effect of Fe2O3 crystal phases on their performance in CO2 hydrogenation was studied. α-Fe2O3 crystal was prepared by precipitation method from Fe(NO3)3·9H2O and (NH4)2CO3, and γ-Fe2O3 was prepared by grinding Fe(NO3)3·9H2O and L(+)-Tartaric acid in agate mortar completely. The crystal phases of Fe2O3 influence the distribution of promoter Zn, K and Cu on catalysts. The dispersity of K on γ-Fe2O3 surface is higher than α-Fe2O3. On the contrary, Cu and Zn are more dispersive on α-Fe2O3 surface than γ-Fe2O3. The catalyst in γ-Fe2O3 phase is easily reduced relative to the catalyst in α-Fe2O3 phase. The former presents higher CO2 conversion and C2+ hydrocarbon selectivity than the latter in CO2 hydrogenation.

Effects of Weak Surface Modification on Co/SiO2 Catalyst for Fischer-Tropsch Reaction.

A weak surface modification is applied to Co/SiO2 catalyst by hydrothermal treatment at 180°C for 5 h. Aluminum is introduced to Co/SiO2 catalysts during the surface modification. The effects of surface modification on Co/SiO2 catalyst are studied by changing the operating sequences of surface modification and cobalt impregnation in the catalyst preparation. Surface modification before cobalt impregnation makes Co3O4 particle small and dispersed into the deep part of enlarged pore in SiO2, while surface modification after cobalt impregnation does not obviously change the particle size of Co3O4. The improved amplitude of catalytic activity is similar for the two kinds of catalysts, but they are benefited from different factors. The content of iso-hydrocarbons in the products is increased by the surface modifications.