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The catalytic conversion of CO 2 to CO via a reverse water gas shift (RWGS) reaction followed by well-established synthesis gas conversion technologies may provide a potential approach to convert CO 2 to valuable chemicals and fuels. However, this reaction is mildly endothermic and competed by a strongly exothermic CO 2 methanation reaction at low temperatures. Therefore, the improvement in the low-temperature activities and selectivity of the RWGS reaction is a key challenge for catalyst designs. We reviewed recent advances in the design strategies of supported metal catalysts for enhancing the activity of CO 2 conversion and its selectivity to CO. These strategies include varying support, tuning metal–support interactions, adding reducible transition metal oxide promoters, forming bimetallic alloys, adding alkali metals, and enveloping metal particles. These advances suggest that enhancing CO 2 adsorption and facilitating CO desorption are key factors to enhance CO 2 conversion and CO selectivity. This short review may provide insights into future RWGS catalyst designs and optimization.

Electrochemical reduction of CO2 to value-added chemicals has been hindered by poor product selectivity and competition from hydrogen evolution reactions. This study aims to unravel the origin of the product selectivity and competitive hydrogen evolution reaction on [MP]0 catalysts (M = Fe, Co, Rh and Ir; P is porphyrin ligand) by analyzing the mechanism of CO2 reduction and H2 formation based on the results of density functional theory calculations. Reduction of CO2 to CO and HCOO− proceeds via the formation of carboxylate adduct ([MP-COOH]0 and ([MP-COOH]−) and metal-hydride [MP-H]−, respectively. Competing proton reduction to gaseous hydrogen shares the [MP-H]− intermediate. Our results show that the pKa of [MP-H]0 can be used as an indicator of the CO or HCOO−/H2 preference. Furthermore, an ergoneutral pH has been determined and used to determine the minimum pH at which selective CO2 reduction to HCOO− becomes favorable over the H2 production. These analyses allow us to understand the product selectivity of CO2 reduction on [FeP]0, [CoP]0, [RhP]0 and [IrP]0; [FeP]0 and [CoP]0 are selective for CO whereas [RhP]0 and [IrP]0 are selective for HCOO− while suppressing H2 formation. These descriptors should be applicable to other catalysts in an aqueous medium.

Background Excessive reactive oxygen species (ROS) can cause serious damage to the human body and may cause various chronic diseases. Studies have found that lactic acid bacteria (LAB) have antioxidant and anti-aging effects, and are important resources for the development of microbial antioxidants. This paper was to explore the potential role of an antioxidant strain, Lactobacillus plantarum NJAU-01 screened from traditional dry-cured meat product Jinhua Ham in regulating D-galactose-induced subacute senescence of mice. A total of 48 specific pathogen free Kun Ming mice (SPF KM mice) were randomly allocated into 6 groups: control group with sterile saline injection, aging group with subcutaneously injection of D-galactose, treatments groups with injection of D-galactose and intragastric administration of 10 7 , 10 8 , and 10 9 CFU/mL L. plantarum NJAU-01, and positive control group with injection of D-galactose and intragastric administration of 1 mg/mL Vitamin C. Results The results showed that the treatment group of L. plantarum NJAU-01 at 10 9 CFU/mL showed higher total antioxidant capacity (T-AOC) and the antioxidant enzymatic activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) than those of the other groups in serum, heart and liver. In contrast, the content of the oxidative stress marker malondialdehyde (MDA) showed lower levels than the other groups (P < 0.05). The antioxidant capacity was improved with the supplement of the increasing concentration of L. plantarum NJAU-01. Conclusions Thus, this study demonstrates that L. plantarum NJAU-01 can alleviate oxidative stress by increasing the activities of enzymes involved in oxidation resistance and decreasing level of lipid oxidation in mice.

Crystal structures of peroxisome proliferator-activated receptor gamma (PPARγ) have revealed overlapping binding modes for synthetic and natural/endogenous ligands, indicating competition for the orthosteric pocket. Here we show that cobinding of a synthetic ligand to the orthosteric pocket can push natural and endogenous PPARγ ligands (fatty acids) out of the orthosteric pocket towards an alternate ligand-binding site near the functionally important omega (Ω)-loop. X-ray crystallography, NMR spectroscopy, all-atom molecular dynamics simulations, and mutagenesis coupled to quantitative biochemical functional and cellular assays reveal that synthetic ligand and fatty acid cobinding can form a ‘ligand link’ to the Ω-loop and synergistically affect the structure and function of PPARγ. These findings contribute to a growing body of evidence indicating ligand binding to nuclear receptors can be more complex than the classical one-for-one orthosteric exchange of a natural or endogenous ligand with a synthetic ligand.

Dietary fat is an important part of human diet and has a close relationship with human health. However, it is still unclear how gut microbiota in adolescent responds to dietary fats at a normal dose. In this study, fat-free group (BC) was used as blank control group, we explored blood index and gut microbiota structure in growing rat(aged 1 months) after feeding a normal dose of 16.9% stewed lard(SL), refined lard(RL), fish oil(FO) and soybean oil(SO) for 6 weeks, respectively. The results showed that compared with RL group, SL group showed reduced fasting blood sugar and blood lipid levels and improved nutrient absorption capacity of the intestine. The blood indexes of glucose (Glu), total cholesterol (TC) and total triglyceride (TG) in FO treatment group were relatively low. The abundance of Bacteroidetes in the BC group decreased, and the abundance of Firmicutes increased. The Firmicutes/Bacteroidetes ratio of the FO group was relatively low, and the Firmicutes/Bacteroidetes ratio of the SL group and the SO group was lower than that of the RL group. The abundance of Bacteroidaceae in the SL group was increased. Research results showed that fat-free diets will increase the risk of obesity to a certain extent; compared with refined lard, stewed lard, soybean oil and fish oil can reduce the risk of obesity to a certain extent. The present study could find that the addition and types of dietary fat will affect the abundance and diversity of rat intestinal flora, and provide some information for nutritional evaluation about these dietary lipids.

Propane oxidative dehydrogenation (ODH) is an energy-efficient approach to produce propylene. However, ODH suffers from low propylene selectivity due to a relatively higher activation barrier for propylene formation compared with that for further oxidation. In this work, calculations based on density functional theory were performed to map out the reaction pathways of propane ODH on the surfaces (001) and (010) of nickel oxide hydroxide (NiOOH). Results show that propane is physisorbed on both surfaces and produces propylene through a two-step radical dehydrogenation process. The relatively low activation barriers of propane dehydrogenation on the NiOOH surfaces make the NiOOH-based catalysts promising for propane ODH. By contrast, the weak interaction between the allylic radical and the surface leads to a high activation barrier for further propylene oxidation. These results suggest that the catalysts based on NiOOH can be active and selective for the ODH of propane toward propylene.

Surface morphology of Cu-based catalysts is considered as an important factor affecting both activity and product selectivity of electrochemical reduction of CO2. In this work, surface cavity effect on C2H4 formation was investigated using Cu2O cubes: solid cubes, cavity cubes, and broken cubes, typically representing smooth surface, cavity surface, and rough surface. With respect of C2H4 selectivity, cavity cubes show the significantly enhanced faradaic efficiency (FE) of C2H4, which is 2.7 and 1.7 times higher than those for solid cubes and broken cubes respectively. Moreover, a ratio of CO produced by CO2 reduction reaction (CO2RR) converted to CH4 and C2H4 was calculated to assess the extent of CO further reduction for a catalyst. As noted, cavity cubes exhibited a highest ratio of 29.5%, in contrast with the lower ratio of 13.0% on broken cubes and 14.9% on solid cubes. Consequently, the role of surface cavity is reflected in two effects, the increased CO formation due to higher electrochemical surface area as compared to the smooth surface, and meanwhile the increased ratio of CO converted to hydrocarbons and alcohols due to porous feature as compared to the rough surface with a comparable high electrochemical active surface area (ECSA). What’s more, when applied in a flow cell reactor with a gas diffusion electrode, cavity cubes also achieved much higher C2 selectivity of 37.7% FEC2 than solid cubes and broken cubes. Our work provides a facile strategy for improving the catalytic C2+ product selectivity of Cu2O-based catalysts for CO2RR through modifying surface morphology.Graphical abstract

The electrochemical conversion of CO2-H2O into CO-H2 using renewable energy is a promising technique for clean syngas production. Low-cost electrocatalysts to produce tunable syngas with a potential-independent CO/H2 ratio are highly desired. Herein, a series of N-doped carbon nanotubes encapsulating binary alloy nanoparticles (MxNi-NCNT, M= Fe, Co) were successfully fabricated through the co-pyrolysis of mela-mine and metal precursors. The MxNi-NCNT samples exhibited bamboo-like nanotubular structures with a large specific surface area and high degree of graphitization. Their electrocatalytic performance for syngas production can be tuned by changing the alloy compositions and modifying the electronic structure of the carbon nanotube through the encapsulated metal nanoparticles. Consequently, syngas with a wide range of CO/H2 ratios, from 0.5:1 to 3.4:1, can be produced on MxNi-NCNT. More importantly, stable CO/H2 ratios of 2:1 and 1.5:1, corresponding to the ratio to produce biofuels by syngas fermentation, could be realized on Co1Ni-NCNT and Co2Ni-NCNT, respectively, over a potential window of −0.8 to −1.2 V versus the reversible hydrogen electrode. Our work provides an approach to develop low-cost and potential-independent electrocatalysts to effectively produce syngas with an adjustable CO/H2 ratio from electrochemical CO2 reduction.

Background Current management of patients with atrial fibrillation (AF) is limited by low detection of AF, non‐adherence to guidelines and lack of consideration of patient's preferences, thus highlighting the need for a holistic and integrated approach to AF management. This study aims to determine whether a mHealth technology‐supported AF integrated management strategy will reduce AF‐related adverse events. Methods/design The mAFA II trial is a prospective, cluster randomised controlled trial. The 40 sites will be randomised to mAFA‐integrated care intervention or usual care arms. Prior to randomisation, study sites will be paired to be matched in size and the proportion of study eligible patients. All AF patients aged over 18 years old with CHA2DS2‐VASc score ≥ 2 will be enrolled. Assuming a composite adverse event rate of 10% pre‐intervention, reduced to 5% after intervention, we aim to recruit 3660 patients assuming a 10% loss to follow‐up. The primary study endpoint is a composite of stroke/thromboembolism, all‐cause death and rehospitalisation. Ancillary analyses would determine patient‐related outcome measures, health economics and cost effectiveness, as well as an embedded qualitative study. Discussion The mAFA II trial will provide evidence for an integrated care approach to holistic AF care, supported by mobile health technology to improve screening, patient involvement and optimisation of management.

Partial or total replacement of pork fat with homologous functional oils may meet consumer demand for healthy meat products while preserving their sensory quality. This study investigated the use of lard-derived diacylglycerol (DG) as a fat replacer on the flavor characteristics of frankfurters. The results revealed that substituting pork fat with purified glycerolized lard (PGL) at different levels (25%, 50%, and 100%) increased the water content and water activity, improved the L* and b* values, and protein thermal stability, while decreasing the a* value of frankfurters. Meanwhile, electronic nose results showed that replacing pork fat with PGL affected the aroma of frankfurters. Furthermore, gas chromatography–mass spectrometry detected 50 volatile compounds in all the frankfurters (such as aldehydes, alcohols, terpenes, and aromatic hydrocarbons, etc.). Replacing lard with PGL significantly increased the variety and content of flavor compounds in frankfurters (p < 0.05). According to the approximate odor activity values (OAV) > 1 and variable importance in projection (VIP) > 1, the distinct flavor of the frankfurters with different levels of PGL mainly resulted from aldehydes, alcohols, and terpenes. Generally, this study provided a valuable theoretical foundation for substituting fat with lard-derived DG to improve the flavor characteristics of frankfurters.