Layered Double Hydroxide Nanosheets: Synthesis Strategies and Applications in the Field of Energy Conversion.

In recent years, layered double hydroxides (LDH) nanosheets have garnered substantial attention as intriguing inorganic anionic layered clay materials. These nanosheets have captured the attention of researchers due to their unique physicochemical properties. This review aims to showcase the latest advancements in laboratory research concerning LDH nanosheets, with a specific emphasis on their methods of preparation. This review provides detailed insights into the factors influencing the anionic conductivity of LDH, along with delineating the applications of LDH nanosheets in the realm of energy conversion. Notably, the review highlights the crucial role of LDH nanosheets in the oxygen evolution reaction (OER), a vital process in water splitting and diverse electrochemical applications. The review emphasizes the significant potential of LDH nanosheets in enhancing supercapacitor technology, owing to their high surface area and exceptional charge storage capacity. Additionally, it elucidates the prospective application of LDH nanosheets as anion exchange membranes in anion exchange membrane fuel cells, potentially revolutionizing fuel cell performance through improved efficiency and stability facilitated by enhanced ion transport properties.

Preparation and performance evaluation of non-foaming styrene-acrylic latex for cementing slurry.

The latex used conventionally for oil-well cementing can lead to serious foaming issues in the cement slurry, which not only affects the accurate measurement of the density of the latex-containing cement slurry, but also is detrimental to cementing construction. A large amount of a foam stabilizer used for latex preparation is mainly responsible for foaming of the latex-containing cement slurry. In this study, soap-free emulsion polymerization was conducted using 2-acrylamido-2-methylpropanesulfonic acid (AMPS), styrene (St), and butyl acrylate (BA) as the reaction monomers and the effects of the AMPS dosage, monomer ratio, reaction temperature and stirring speed on the performance of the latex were investigated. The optimum synthesis conditions included a 30% monomer concentration, an St : BA : AMPS monomer ratio of 5 : 4 : 6, a synthesis temperature of 85°C, a stirring speed of 400 r.p.m. and 1.5% of the initiator. As-prepared latex exhibited good filtration loss control, excellent freeze-thaw stability, and extremely low foaming of the cement slurry with the added latex, which was extremely beneficial for on-site cementing construction.

Understanding metabolic alterations after SARS-CoV-2 infection: insights from the patients' oral microenvironmental metabolites.

BACKGROUND: Coronavirus disease 2019 is a type of acute infectious pneumonia and frequently confused with influenza since the initial symptoms. When the virus colonized the patient's mouth, it will cause changes of the oral microenvironment. However, few studies on the alterations of metabolism of the oral microenvironment affected by SARS-CoV-2 infection have been reported. In this study, we explored metabolic alterations of oral microenvironment after SARS-CoV-2 infection. METHODS: Untargeted metabolomics (UPLC-MS) was used to investigate the metabolic changes between oral secretion samples of 25 COVID-19 and 30 control participants. To obtain the specific metabolic changes of COVID-19, we selected 25 influenza patients to exclude the metabolic changes caused by the stress response of the immune system to the virus. Multivariate analysis (PCA and PLS-DA plots) and univariate analysis (students' t-test) were used to compare the differences between COVID-19 patients and the controls. Online hiplot tool was used to perform heatmap analysis. Metabolic pathway analysis was conducted by using the MetaboAnalyst 5.0 web application. RESULTS: PLS-DA plots showed significant separation of COVID-19 patients and the controls. A total of 45 differential metabolites between COVID-19 and control group were identified. Among them, 35 metabolites were defined as SARS-CoV-2 specific differential metabolites. Especially, the levels of cis-5,8,11,14,17-eicosapentaenoic acid and hexanoic acid changed dramatically based on the FC values. Pathway enrichment found the most significant pathways were tyrosine-related metabolism. Further, we found 10 differential metabolites caused by the virus indicating the body's metabolism changes after viral stimulation. Moreover, adenine and adenosine were defined as influenza virus-specific differential metabolites. CONCLUSIONS: This study revealed that 35 metabolites and tyrosine-related metabolism pathways were significantly changed after SARS-CoV-2 infection. The metabolic alterations of oral microenvironment in COVID-19 provided new insights into its molecular mechanisms for research and prognostic treatment.

Preparation of Montmorillonite Nanosheets with a High Aspect Ratio through Heating/Rehydrating and Gas-Pushing Exfoliation.

Montmorillonite (MMT) is an abundant silicate mineral with ultrahigh stability. The exfoliation of stacked MMT into high-aspect-ratio nanosheets is of crucial importance for various applications such as toxic gas suppression, barrier property enhancement, flame retardancy, and ion conduction. In this work, we develop a new heating/rehydrating and gas-pushing method that can successfully exfoliate MMT into nanosheets with aspect ratios (600-5000) far higher than the currently reported values (1-120). The MMT first goes through a "starvation pretreatment" under different heating temperatures to improve its hydrophilicity and is then rehydrated in a hydrogen peroxide solution. The hydrogen peroxide in the MMT interlayer space can decompose into water and oxygen bubbles, thus finally leading to the exfoliation via gas-pushing while preserving the large lateral size (mainly in the range of 1-6 µm) of the nanosheets. By changing the pretreatment temperature and pH value of the hydrogen peroxide solution, the exfoliation performance can be tuned. This simple and low-cost exfoliation method is promising to achieve the mass production of MMT nanosheets with a high aspect ratio and may promote its application in various fields such as energy conversion, drug delivery, and photocatalysis.

Preparation of highly dispersed Pd/SBA-15 catalysts for dodecahydro-N-ethylcarbazole dehydrogenation reaction by ion exchange-glow discharge.

Dehydrogenation reactions are critical in hydrogen storage based on a liquid organic hydrogen carrier (LOHC) system. Speeding up the dehydrogenation rate and lowering the reaction temperature are the main focuses of LOHC dehydrogenation catalysts. In this paper, Pd/SBA-15 catalysts (Pd-IP/S15) were prepared by NaOH treatment of surface hydroxyl groups on SBA-15, the ion exchange of Na+ with Pd(NH3)42+, and then reduction of Pd ions via glow discharge plasma. The dehydrogenation performance of dodecahydro-N-ethylcarbazole on the prepared catalysts is studied. The turnover frequency of Pd-IP/S15 is 13.94 min-1 at 170°C, which is 10.25 times that of commercial Pd/C. It is ensured via the ion exchange method that Pd(NH3)42+ could be precisely targeted at the Si-OH of SBA-15 to form Si-O-Pd(NH3)42+, which effectively prevents the aggregation and uncontrollable growth of Pd nanoparticles (NPs) during the in situ reduction by plasma. Pd NPs with high dispersion are obtained on SBA-15, which enhances the catalytic activity of Pd-IP/S15. The coordination of Pd NPs with O of Si-OH on SBA-15 enabled Pd-IP/S15 to exhibit excellent catalytic stability. After 7 dehydrogenation cycles at 180°C, the dehydrogenation efficiency remained above 97%.

Metagenomic analysis reveals oropharyngeal microbiota alterations in patients with COVID-19.

COVID-19 remains a serious emerging global health problem, and little is known about the role of oropharynx commensal microbes in infection susceptibility and severity. Here, we present the oropharyngeal microbiota characteristics identified by shotgun metagenomic sequencing analyses of oropharynx swab specimens from 31 COVID-19 patients, 29 influenza B patients, and 28 healthy controls. Our results revealed a distinct oropharyngeal microbiota composition in the COVID-19 patients, characterized by enrichment of opportunistic pathogens such as Veillonella and Megasphaera and depletion of Pseudopropionibacterium, Rothia, and Streptococcus. Based on the relative abundance of the oropharyngeal microbiome, we built a microbial classifier to distinguish COVID-19 patients from flu patients and healthy controls with an AUC of 0.889, in which Veillonella was identified as the most prominent biomarker for COVID-19 group. Several members of the genus Veillonella, especially Veillonella parvula which was highly enriched in the oropharynx of our COVID-19 patients, were also overrepresented in the BALF of COVID-19 patients, indicating that the oral cavity acts as a natural reservoir for pathogens to induce co-infections in the lungs of COVID-19 patients. We also found the increased ratios of Klebsiella sp., Acinetobacter sp., and Serratia sp. were correlated with both disease severity and elevated systemic inflammation markers (neutrophil-lymphocyte ratio, NLR), suggesting that these oropharynx microbiota alterations may impact COVID-19 severity by influencing the inflammatory response. Moreover, the oropharyngeal microbiome of COVID-19 patients exhibited a significant enrichment in amino acid metabolism and xenobiotic biodegradation and metabolism. In addition, all 26 drug classes of antimicrobial resistance genes were detected in the COVID-19 group, and were significantly enriched in critical cases. In conclusion, we found that oropharyngeal microbiota alterations and functional differences were associated with COVID-19 severity.

A continuous plutonium aerosol monitor for use in high radon environments.

Radon concentration is very high in underground basements and other facilities. Radon concentration in a nuclear facility locates in the granite tunnel can be as high as 10(4) Bq m(-3) in summer. Monitoring plutonium aerosol in this circumstance is seriously interfered by radon daughters. In order to solve this problem, a new continuous aerosol monitor that can monitor very low plutonium aerosol concentration in high radon background was developed. Several techniques were used to reduce interference of radon daughters, and the minimum detectable concentrations in various radon concentrations were measured.

MRNA levels of two different enzymes in hepatocellular carcinoma.

BACKGROUND/AIMS: To investigate in patients the relationship between hepatocellular carcinoma and expression levels of cytochrome P450 IIE1 and glutathione S-transferaseP1 METHODOLOGY: Peripheral blood was collected from 65 patients with hepatocellular carcinoma, and 65 healthy controls. Real-time polymerase chain reaction was used in this research. RESULTS: The average mRNA levels of CYPIIE1 in HCC and healthy controls are 11.09% and 2.13%, respectively, while the average mRNA levels of GSTP1 in HCC and healthy controls are 0.61% and 2.34%, respectively. The mRNA level of CYPIIE1 was higher, and that of GSTP1 was lower, in patients with HCC compared to healthy controls. The difference of the mRNA levels of two enzymes in HCC has a statistical significance (p < 0.001). CONCLUSIONS: In this group of HCC patients and healthy controls, we found that patients with HCC tended to have higher expression of CYPIIE1 and lower expression of GSTP1. Our study indicate that CYPIIE1 is maybe the ruinous gene that results in an increased incidence of HCC, while GSTP1 is maybe the protection gene for hepatic cells during the whole course of metabolization.