No abstract

The conversion of CO2 into fuels and feedstock chemicals via photothermal catalysis holds promise for efficient solar energy utilization to tackle the global energy shortage and climate change. Despite recent advances, it is of emerging interest to explore promising materials with excellent photothermal properties to boost the performance of photothermal CO2 catalysis. Here, we report the discovery of MXene materials as superior photothermal supports for metal nanoparticles. As a proof-of-concept study, we demonstrate that Nb2C and Ti3C2, two typical MXene materials, can enhance the photothermal effect and thus boost the photothermal catalytic activity of Ni nanoparticles. A record CO2 conversion rate of 8.50 mol·gNi –1·h–1 is achieved for Nb2C-nanosheet-supported Ni nanoparticles under intense illumination. Our study bridges the gap between photothermal MXene materials and photothermal CO2 catalysis toward more efficient solar-to-chemical energy conversions and stimulates the interest in MXene-supported metal nanoparticles for other heterogeneous catalytic reactions, particularly driven by sunlight.

The efficiency of heterogeneous photocatalysis for converting solar to chemical energy is low on a per photon basis mainly because of the difficulty of capturing and utilizing light across the entire solar spectral wavelength range. This challenge is addressed herein with a plasmonic superstructure, fashioned as an array of nanoscale needles comprising cobalt nanocrystals assembled within a sheath of porous silica grown on a fluorine tin oxide substrate. This plasmonic superstructure can strongly absorb sunlight through different mechanisms including enhanced plasmonic excitation by the hybridization of Co nanoparticles in close proximity, as well as inter‐ and intra‐band transitions. With nearly 100% sunlight harvesting ability, it drives the photothermal hydrogenation of carbon dioxide with a 20‐fold rate increase from the silica‐supported cobalt catalyst. The present work bridges the gap between strong light‐absorbing plasmonic superstructures with photothermal CO2 catalysis toward the complete utilization of the solar energy.

Background:The biochemical mechanism of nicotine biodegradation is important. Results: An NADH-dependent and FAD-containing hydroxylase (HspB) for nicotine degradation was purified and mechanistically characterized. Conclusion: The hydroxylase is crucial for nicotine degradation by Pseudomonas putida. Significance: The novel HspB provides a sound basis for future studies aimed at a better understanding of the molecular principles of nicotine degradation.

Besides mosquitoes, ticks are regarded as the primary source of vector-borne infectious diseases. Indeed, a wide variety of severe infectious human diseases, including those involving viruses, are transmitted by ticks in many parts of the world. To date, there are no published reports on the use of next-generation sequencing for studying viral diversity in ticks or discovering new viruses in these arthropods from China. Here, Ion-torrent sequencing was used to investigate the presence of viruses in three Rhipicephalus spp. tick pools (NY-11, NY-13, and MM-13) collected from the Menglian district of Yunnan, China. The sequencing run resulted in 3,641,088, 3,106,733, and 3,871,851 reads in each tick pool after trimming. Reads and assembled contiguous sequences (contigs) were subject to basic local alignment search tool analysis against the GenBank database. Large numbers of reads and contigs related to known viral sequences corresponding to a broad range of viral families were identified. Some of the sequences originated from viruses that have not been described previously in ticks. Our findings will facilitate better understanding of the tick virome, and add to our current knowledge of disease-causing viruses in ticks living under natural conditions.

Previous research suggested that Pseudomonas spp. may attack the pyrrolidine ring of nicotine in a way similar to mammalian metabolism, resulting in the formation of pseudooxynicotine, the direct precursor of a potent tobacco-specific lung carcinogen. In addition, the subsequent intermediates, 6-hydroxy-3-succinoylpyridine (HSP) and 2,5-dihydroxypyridine (DHP) in the Pseudomonas nicotine degradation pathway are two important precursors for drug syntheses. However, there is little information on the molecular mechanism for nicotine degradation via the pyrrolidine pathway until now. In this study we cloned and sequenced a 4,879-bp gene cluster involved in nicotine degradation. Intermediates N-methylmyosmine, pseudooxynicotine, 3-succinoylpyridine, HSP, and DHP were identified from resting cell reactions of the transformant containing the gene cluster and shown to be identical to those of the pyrrolidine pathway reported in wild-type strain Pseudomonas putida S16. The gene for 6-hydroxy-3-succinoylpyridine hydroxylase (HSP hydroxylase) catalyzing HSP directly to DHP was cloned, sequenced, and expressed in Escherichia coli, and the purified HSP hydroxylase (38 kDa) is NADH dependent. DNA sequence analysis of this 936-bp fragment reveals that the deduced amino acid shows no similarity with any protein of known function.

A follow-up meta-analysis for wordproblem-solving interventions for students with mathematics difficulties.

Even though there were slight percentage changes between contact lens wearers and nonwearers in some microbes, there were no differences in their diversity. On the other hand, contact lens usage might cause relative abundance of some taxa to change. Our results will help assess whether or not conjunctival microbiome changes caused by contact lens wear affect infection risk.