Ethylene Methoxycarbonylation over Heterogeneous Pt1/MoS2 Single-Atom Catalyst: Metal-Support Concerted Catalysis.

Ethylene methoxycarbonylation (EMC) to methyl propanoate (MP) is an industrially important reaction and commercially uses a homogeneous Pd-phosphine organometallic complex as the catalyst and corrosive strong acid as the promoter. In this work, we develop a Pt1/MoS2 heterogeneous single-atom catalyst (SAC) which exhibits high activity, selectivity, and good recyclability for EMC reaction without need of any liquid acid. The production rate of MP achieves 0.35 gMP gcat-1 h-1 with MP selectivity of 91.1% at 1 MPa CO, 1 MPa C2H4, and 160 °C, which can be doubled at 2 MPa CO and corresponds to 320.1 molMP molPt-1 h-1, at least 1 order of magnitude higher than the earlier reported heterogeneous catalyst and even comparable to some of homogeneous catalyst. Advanced characterizations and DFT calculations reveal that all the Pt single atoms are located at the Mo vacancies along the Mo edge of the MoS2 nanosheets, forming pocket-like Mo-S-Pt1-S-Mo ensembles with uniform and well-defined structure. Methanol is first adsorbed and dissociated on Mo sites, and the produced H spillovers to the adjacent Pt site forming Pt-H species which then activate ethylene, forming Pt-ethyl species. Meanwhile, CO adsorbed on the other Mo site reacts with the Pt-ethyl species, yielding propionyl species, and this carbonylation is the rate-determining step. The final methoxylation step proceeds via the nucleophilic attack of propionyl species by -OCH3 affording the final product MP. Such a metal-support concerted catalysis enabled by the Mo-S-Pt1-S-Mo multisite ensemble opens a new avenue for SACs to promote the multimolecular reactions that prevail in homogeneous catalysis.

Suppressing Metal Leaching and Sintering in Hydroformylation Reaction by Modulating the Coordination of Rh Single Atoms with Reactants.

Hydroformylation reaction is one of the largest homogeneously catalyzed industrial processes yet suffers from difficulty and high cost in catalyst separation and recovery. Heterogeneous single-atom catalysts (SACs), on the other hand, have emerged as a promising alternative due to their high initial activity and reasonable regioselectivity. Nevertheless, the stability of SACs against metal aggregation and leaching during the reaction has rarely been addressed. Herein, we elucidate the mechanism of Rh aggregation and leaching by investigating the structural evolution of Rh1@silicalite-1 SAC in response to different adsorbates (CO, H2, alkene, and aldehydes) by using diffuse reflectance infrared Fourier transform spectroscopy, X-ray adsorption fine structure, and scanning transmission electron microscopy techniques and kinetic studies. It is discovered that the aggregation and leaching of Rh are induced by the strong adsorption of CO and aldehydes on Rh, as well as the reduction of Rh3+ by CO/H2 which weakens the binding of Rh with support. In contrast, alkene effectively counteracts this effect by the competitive adsorption on Rh atoms with CO/aldehyde, and the disintegration of Rh clusters. Based on these results, we propose a strategy to conduct the reaction under conditions of high alkene concentration, which proves to be able to stabilize Rh single atom against aggregation and/or leaching for more than 100 h time-on-stream.

Ruthenium Complexes with NNN-Pincer Ligands for N-Methylation of Amines Using Methanol.

A series of ruthenium complexes (Ru1-Ru4) bearing new NNN-pincer ligands were synthesized in 58-78% yields. All of the complexes are air and moisture stable and were characterized by IR, NMR, and high-resolution mass spectra (HRMS). In addition, the structures of Ru1-Ru3 were confirmed by X-ray crystallographic analysis. These Ru(II) complexes exhibited high catalytic efficiency and broad functional group tolerance in the N-methylation reaction of amines using CH3OH as both the C1 source and solvent. Experimental results indicated that the electronic effect of the substituents on the ligands considerably affects the catalytic reactivity of the complexes in which Ru3 bearing an electron-donating OMe group showed the highest activity. Deuterium labeling and control experiments suggested that the dehydrogenation of methanol to generate ruthenium hydride species was the rate-determining step in the reaction. Furthermore, this protocol also provided a ready approach to versatile trideuterated N-methylamines under mild conditions using CD3OD as a deuterated methylating agent.

Severe pediatric adenoviral pneumonia combined with invasive pulmonary aspergillosis.

BACKGROUND: This study aimed to analyze the clinical characteristics of severe pediatric adenoviral pneumonia combined with invasive pulmonary aspergillosis. METHODS: We retrospectively analyzed the clinical data of five children clinically diagnosed with severe adenoviral pneumonia combined with invasive pulmonary aspergillosis at Xiamen Children's Hospital. RESULTS: These five children included one boy and four girls, with ages of onset ranging from 8 months and 15 days to 2 years and 2 months. All of them had fever with a mean duration of 11-35 days and cough. Pulmonary imaging was performed, which revealed solid pulmonary opacification in all five children, pleural effusion in two children, and emphysema and multiple small cavity formations in one child. Multiple microbiological tests were performed on the 5 children, and adenovirus was positive in the alveolar lavage fluid for the first time, and aspergillus culture was positive in the second test. On tracheoscopy, the bronchial mucosa was seen to be congested and edematous or pale and eroded; white moss-like material was seen adhering to the tracheal wall or even blocking the airway. The five children were treated with a combination of two or more broad-spectrum antimicrobials, glucocorticoids, and gamma globulins and underwent bronchoscopy. Voriconazole was added in the treatment regimen after the diagnosis of aspergillosis (28-34 days of treatment). Four of the children were discharged in good condition with a mean total length of hospital stay of 17-47 days. The other child leave against medical advice. Follow-up 3-5 months after discharge showed that one child had been cured; two children had developed obliterative bronchiolitis; one child had developed bronchiectasis; and the remaining child who had been discharged spontaneously was not contactable via telephone. CONCLUSIONS: Immune disorders and antibiotic and steroid treatments for adenovirus infection are high-risk factors for secondary invasive pulmonary aspergillosis in children. Prolonged fever and cough are the main manifestations, but which lack specificity, and bronchoscopic mucosal-specific injury evaluation and alveolar lavage fluid culture are helpful in the diagnosis of aspergillosis. The long-term prognosis of severe pediatric adenoviral pneumonia combined with invasive pulmonary aspergillosis maybe poor.

Potential-Driven Restructuring of Cu Single Atoms to Nanoparticles for Boosting the Electrochemical Reduction of Nitrate to Ammonia.

Restructuring is ubiquitous in thermocatalysis and of pivotal importance to identify the real active site, yet it is less explored in electrocatalysis. Herein, by using operando X-ray absorption spectroscopy in conjunction with advanced electron microscopy, we reveal the restructuring of the as-synthesized Cu-N4 single-atom site to the nanoparticles of ∼5 nm during the electrochemical reduction of nitrate to ammonia, a green ammonia production route upon combined with the plasma-assisted oxidation of nitrogen. The reduction of Cu2+ to Cu+ and Cu0 and the subsequent aggregation of Cu0 single atoms is found to occur concurrently with the enhancement of the NH3 production rate, both of them are driven by the applied potential switching from 0.00 to -1.00 V versus RHE. The maximum production rate of ammonia reaches 4.5 mg cm-2 h-1 (12.5 molNH3 gCu-1 h-1) with a Faradaic efficiency of 84.7% at -1.00 V versus RHE, outperforming most of the other Cu catalysts reported previously. After electrolysis, the aggregated Cu nanoparticles are reversibly disintegrated into single atoms and then restored to the Cu-N4 structure upon being exposed to an ambient atmosphere, which masks the potential-induced restructuring during the reaction. The synchronous changes of the Cu0 percentage and the ammonia Faradaic efficiency with the applied potential suggests that the Cu nanoparticles are the genuine active sites for nitrate reduction to ammonia, which is corroborated with both the post-deposited Cu NP catalyst and density functional theory calculations.

Highly active and stable Ir nanoclusters derived from Ir1/MgAl2O4 single-atom catalysts.

Single-atom catalysts (SACs) prepared by the atom trapping method often possess high stability yet have limited advantages regarding catalytic performance due to the strong metal-support interaction. Using these SACs as seeds to develop supported nanoclusters or nanoparticles has, however, been proven to be effective in improving the catalysts' intrinsic activity. Herein, we have prepared extremely stable Ir SACs supported by MgAl2O4 via atomic trapping and used them as seeds to fabricate highly active and stable Ir nanocluster catalysts by high-temperature reduction. The activity toward N2O decomposition increased by more than ten times compared with that of the parent Ir SACs. This study provides a new avenue to design and develop highly active and stable catalysts for industrial use.

Severe dyspnea and uncontrolled seizures following meperfluthrin poisoning: a case report.

BACKGROUND: Meperfluthrin is a novel sanitary cyhalothrin insecticide invented in China and has increasingly been used to produce liquid mosquito repellents. Oral meperfluthrin poisoning in human has rarely been reported. Here, we reported a case of meperfluthrin poisoning by ingestion of a meperfluthrin-based liquid mosquito repellent in a 16-month-old infant. CASE PRESENTATION: A 16-month-old boy with a history of accident ingestion of meperfluthrin was admitted to our hospital's emergency department. He exhibited severe dyspnea, and lung radiograph showed multiple patchy and cord-like high-density shadows bilaterally in a short time. He also suffered 35 min of seizures which were finally controlled by the intravenous infusion of propofol. He was diagnosed with meperfluthrin poisoning, status epilepticus and severe pneumonia. After treated with methylprednisolone, aerosolized beclomethasone dipropionate, anti-infection, and some critical supportive therapy, the patient was in good health and showed no symptoms during 12 months of follow-up. CONCLUSIONS: Meperfluthrin poisoning is rare. Oral meperfluthrin poisoning shows neurotoxic effects and pulmonary toxicity. Controlling seizures rapidly and ensuring an adequate oxygen supply are critical to the successful treatment.

Highly Selective Transformation of Biomass Derivatives to Valuable Chemicals by Single-Atom Photocatalyst Ni/TiO2.

Selective CC cleavage of the biomass derivative glycerol under mild conditions is recognized as a promising yet challenging synthesis route to produce value-added chemicals. Here, a highly selective catalyst for the transformation of glycerol to the high-value product glycolaldehyde is presented, which is composed of nickel single atoms confined to the surface of titanium dioxide. Driven by light, the catalyst operates under ambient conditions using air as a green oxidant. The optimized catalyst shows a selectivity of over 60% to glycolaldehyde, resulting in 1058 µmol gCat -1  h-1 production rate, and ≈3 times higher turnover number than NiOx -nanoparticle-decorated TiO2 photocatalyst. Diverse operando and in situ spectroscopies unveil the unique function of the Ni single atom, which can significantly promote oxygen adsorption, work as an electron sink, and accelerate the production of superoxide radicals, thereby improving the selectivity toward glycolaldehyde over other by-products.

Clinical analysis of adenovirus pneumonia with pulmonary consolidation and atelectasis in children.

OBJECTIVE: To assess the clinical characteristics of 168 children with adenovirus pneumonia complicated by pulmonary consolidation and atelectasis. METHODS: We retrospectively studied patients with adenovirus pneumonia complicated by pulmonary consolidation and atelectasis admitted to Xiamen Children's Hospital from March 2019 to August 2019. In total, 168 patients were recruited and divided into a severe group and non-severe group according to disease severity. Clinical results were assessed. RESULTS: All children had fever and cough, 29 had wheezing, and 82 had dyspnea. Pleural effusion was found in 53 patients. Mixed infections were present in 95 patients. A total of 105 patients received hormone therapy, 72 received intravenous gamma globulin, and 103 underwent bronchoscopy, among whom 6 were found to have bronchial casts. Of the 168 children, 166 were cured and two died. The patients were divided by disease severity, with 82 in the severe group and 86 in the non-severe group. The two groups showed significant differences in the fever course, pleural effusion, mixed infections, hemoglobin concentration, procalcitonin concentration, and lactate dehydrogenase concentration. CONCLUSION: A long fever course, mixed infection, pleural effusion, decreased hemoglobin concentration, and increased procalcitonin and lactate dehydrogenase concentrations may be associated with more severe adenovirus pneumonia.

Global soil pollution by toxic elements: Current status and future perspectives on the risk assessment and remediation strategies - A review.

The aim of this article is to review and present the state of the arte about the status of toxic elements (TEs) in soils and assess the potential risk using single and total complex pollution indices in a global scale. We compiled, integrated, and analyzed soil TE pollution data over almost a decade through key maps, which have not been reviewed up to date. All the in-situ and ex-situ remediation treatments have been also reviewed, illustrated, and compared, for the first time. The future perspectives have been discussed and summarized. This review demonstrates that the cornerstone maps and integrated information provide reliable geographical coordinates and inclusive information on TEs pollution, particularly in China. In-situ treatment approaches for TEs polluted soils are more cost-effective and applicable than ex-situ treatment trials. Selecting a feasible remediation strategy should to take the extent of contamination, treatment objectives, site characteristics, cost-efficiency, and public suitability into account. The summarized findings in this review may help to develop innovative and applicable methods for assessing the global soil pollution by TEs. Also, these findings may help to develop innovative, applicable, and feasibly economic methods for sustainable management of TEs contaminated soils to mitigate the environmental and human health risk.

Occurrence of seventeen veterinary antibiotics and resistant bacterias in manure-fertilized vegetable farm soil in four provinces of China.

This study focused on the occurrence of seventeen veterinary antibiotics and six resistant bacterias in soils from the vegetable farms fertilized with animal manure in China. Seventeen veterinary antibiotics, including sulfonamides, quinolones, tetracyclines, macrolides and amphenicols, were detected by high performance liquid chromatography/tandem mass spectrometer in all the 53 soil samples collected in four provinces during August 2016. The concentrations of target antibiotics in the soil samples ranged from not detectable to 415.00 µg/kg dry weight with the mean residual levels of the five classes followed order: tetracyclines (82.75 µg/kg) > quinolones (12.78 µg/kg) > macrolides (12.24 µg/kg) > sulfonamides (2.61 µg/kg) > amphenicols (0.06 µg/kg). Moreover, the highest antibiotic levels were found mainly in soil from organic vegetable farms. Risk assessment by using the methods of risk quotient, suggested that oxytetracycline, chlortetracycline, enrofloxacin and ciprofloxacin could pose severe ecological risk in sampled soils. Resistant strains were isolated in 30 samples, with Escherichia coli and Klebsiella pneumonia found the dominant bacterial hosts with resistance genes. Antibiotic resistance genes, including tetA, tetB, qnrS, oqxA, sul1, sul2, ermA and floR, were detected in the strains resistant to: tetracyclines, quinolones, sulfonamides, macrolides and amphenicols resistance, respectively. Overall, there was a correlation between the results of antibiotic risk assessment with the detection of resistance genes from isolated strains in the soils.

Derivation of freshwater water quality criteria for dibutyltin dilaurate from measured data and data predicted using interspecies correlation estimate models.

Dibutyltin dilaurate (DBTL) is an organotin compound that has been widely detected in aquatic environments. However, the ecological risk assessment for DBTL is hard to perform due to the absence of water quality criteria (WQC) and lack of toxicity data. In this study, toxicity data were obtained from acute and chronic toxicity tests using aquatic species resident in China. Based on the species sensitivity distributions (SSDs) constructed from these test data, the acute water quality criterion (AWQC) and chronic water quality criterion (CWQC) were then derived to be 132 µg/L and 31.9 µg/L for DBTL. In order to valid the predicted data in the application to the protective criteria development and hazard assessment, the web-based interspecies correlation estimation (Web-ICE) system was used to estimate acute toxicities. Here two acute toxicity data groups for surrogate species were chosen from experimental data and QSAR Toolbox-predicted data separately, giving estimated data for prediction species using Web-ICE software. According to Kolmogorov-Smirnov test results, Web-ICE-based SSDs and measurement-based SSD were not significantly different. The results showed that the differences between measurement-based (132 µg/L) and Web-ICE-based AWQCs (39.7 µg/L and 58.5 µg/L) were statistically acceptable. Under certain conditions, it is therefore worth considering using the QSAR Toolbox plus Web-ICE method here to provide a beneficial supplement for developing preliminarily screen level toxicities in WQC when little or no relevant information are available. Besides, the geographic distribution of species was demonstrated not to be a significant factor in SSD establishment and WQC derivation.