The incorporation of pentagon‐heptagon pairs into helical nanographenes lacks a facile synthetic route, and the impact of these pairs on chiroptical properties remains unclear. In this study, a ...method for the stepwise construction of pentagon‐heptagon pairs in helical nanographenes by the dehydrogenation of 6helicene units was developed. Three helical nanographenes containing pentagon‐heptagon pairs were synthesized and characterized using this approach. A wide variation in the molecular geometries and photophysical properties of these helical nanographenes was observed, with changes in the helical length of these structures and the introduction of the pentagon‐heptagon pairs. The embedded pentagon‐heptagon pairs reduced the oxidation potential of the synthesized helical nanographenes. The high isomerization energy barriers enabled the chiral resolution of the helicene enantiomers. Chiroptical investigations revealed remarkably enhanced circularly polarized luminescence and luminescence dissymmetry factors with an increasing number of the pentagon‐heptagon pairs.
The controlled dehydrogenation of 6helicene units provides a facile and feasible method for the synthesis of helical nanographenes containing pentagon‐heptagon pairs. The presence of pentagon‐heptagon pairs has proven to be quite effective in modulating the electrochemical and photophysical properties of the resulting nanographenes, including enhanced circularly polarized luminescence.
Layered gallium telluride (GaTe) has attracted much attention recently, due to its extremely high photoresponsivity, short response time, and promising thermoelectric performance. Different from most ...commonly studied two-dimensional (2D) materials, GaTe has in-plane anisotropy and a low symmetry with the C 2h 3 space group. Investigating the in-plane optical anisotropy, including the electron–photon and electron–phonon interactions of GaTe is essential in realizing its applications in optoelectronics and thermoelectrics. In this work, the anisotropic light-matter interactions in the low-symmetry material GaTe are studied using anisotropic optical extinction and Raman spectroscopies as probes. Our polarized optical extinction spectroscopy reveals the weak anisotropy in optical extinction spectra for visible light of multilayer GaTe. Polarized Raman spectroscopy proves to be sensitive to the crystalline orientation of GaTe, and shows the intricate dependences of Raman anisotropy on flake thickness, photon and phonon energies. Such intricate dependences can be explained by theoretical analyses employing first-principles calculations and group theory. These studies are a crucial step toward the applications of GaTe especially in optoelectronics and thermoelectrics, and provide a general methodology for the study of the anisotropy of light-matter interactions in 2D layered materials with in-plane anisotropy.
One approach toward optical nanoimaging involves sequential molecular localization of photoswitchable fluorophores to achieve high resolution beyond optical limit of diffraction. Block copolymer ...micelles assembled from polystryrene-block-poly(ethylene oxide) block copolymers (PSt-b-PEO) are visualized in optical nanoimaging by staining the polystyrene blocks with spiropyrans (SPs). SPs localized in hydrophobic phase of block copolymer micelles exhibit reversible fluorescence on–off switching at alternating irradiation of UV and visible light. Phase-selective distribution of SPs in block copolymer micelles enables optical nanoimaging of microphase structures of block copolymer self-assembly at 50-nm resolution. To date, this is the sturdiest realization of optical nanoimaging with subdiffraction resolution for solution self-assembly of block copolymers.
Photoswitchable fluorescent diarylethenes are promising in molecular optical memory and photonic devices. However, the performance of current diarylethenes is far from satisfactory because of the ...scarcity of high-speed switching capability and large fluorescence on-off ratio. Here we report a trident perylenemonoimide dyad modified by triple dithienylethenes whose photochromic fluorescence quenching ratio at the photostationary state exceeds 10,000 and the fluorescence quenching efficiency is close to 100% within seconds of ultraviolet irradiation. The highly sensitive fluorescence on/off switching of the trident dyad enables recyclable fluorescence patterning and all-optical transistors. The prototype optical device based on the trident dyad enables the optical switching of incident light and conversion from incident light wavelength to transmitted light wavelength, which is all-optically controlled, reversible and wavelength-convertible. In addition, the trident dyad-staining block copolymer vesicles are observed via optical nanoimaging with a sub-100 nm resolution, portending a potential prospect of the dithienylethene dyad in super-resolution imaging.
The potential ecological risks caused by entering radioactive wastewater containing tritium and carbon-14 into the sea require careful evaluation. This study simulated seawater’s tritium and ...carbon-14 pollution and analyzed the effects on the seawater and sediment microenvironments. Tritium and carbon-14 pollution primarily altered nitrogen and phosphorus metabolism in the seawater environment. Analysis by 16S rRNA sequencing showed changes in the relative abundance of microorganisms involved in carbon, nitrogen, and phosphorus metabolism and organic matter degradation in response to tritium and carbon-14 exposure. Metabonomics and metagenomic analysis showed that tritium and carbon-14 exposure interfered with gene expression involving nucleotide and amino acid metabolites, in agreement with the results seen for microbial community structure. Tritium and carbon-14 exposure also modulated the abundance of functional genes involved in carbohydrate, phosphorus, sulfur, and nitrogen metabolic pathways in sediments. Tritium and carbon-14 pollution in seawater adversely affected microbial diversity, metabolic processes, and the abundance of nutrient-cycling genes. These results provide valuable information for further evaluating the risks of tritium and carbon-14 in marine environments.
Human infections with vaccinia virus (VACV), mostly from laboratory accidents or contact with infected animals, have occurred since smallpox was eradicated in 1980. No recent cases have been reported ...in China. We report on an outbreak of VACV from occupational exposure to rabbit skins inoculated with VACV.
We report a novel nanostructured chemosensing ensemble PyNp-C13/UD, obtained by self-assembling uranine dye (UD) and an amphiphilic pyridinium salt PyNp-C13. The ensemble was developed for the ...fluorescence turn-on sensing of ATP in aqueous solutions and inside living cells. The assembly operates via an indicator displacement assay (IDA) method with an ultra-low detection limit of 6.8 nM.
•Single Mo atom embedded at the six-fold cavity with high stability.•Mo decorated g-C3N4 monolayer is promising adsorbent for HCN, H2S, and SO2 and NO.•HCN, SO2, and NO act as acceptors and H2S acts ...as donor.•The adsorption of HCN, SO2, H2S makes the system exhibit semimetal properties.•The magnetism be regulated by the gas molecule adsorption.
In this paper, we explored the adsorption structure, electronic states, and charge transfer of toxic gas molecules, including HCN, SO2, H2S and NO, on pristine and Mo atom embedded graphitic carbon nitride (g-C3N4) by first-principles calculations. Our results show that single Mo atom prefers to be embedded at the six-fold cavity with high stability. The adsorption of those gas molecules on pristine g-C3N4 monolayer exhibits weak interaction, while Mo atom doping can significantly enhance their adsorption energy. Partial density of states analysis illustrate strong hybridization among Mo-4d, gas molecule and g-C3N4. Charge transfer analysis indicates that HCN, SO2, and NO act as acceptors, while H2S acts as donor. The magnetism of g-C3N4/Mo also undergoes great change after the gas molecules adsorption. The adsorption of HCN, SO2, H2S makes the system exhibit semimetal properties, while the adsorption of NO produces much smaller magnetic moment. Therefore, the magnetism of the Mo/g-C3N4 can be modified by the gas molecule adsorption. Our calculations demonstrate that Mo decorated g-C3N4 monolayer can be a promising adsorbent for gas molecule and the variation of magnetic moment through gas adsorption can also be utilized.
Abstract
Background
An orally aerosolized adenovirus type-5 vector-based coronavirus disease 2019 (COVID-19) vaccine (Ad5-nCoV) has recently been authorized for boosting immunization in China. Our ...study aims to assess the environmental impact of the use of aerosolized Ad5-nCoV.
Methods
We collected air samples from rooms, swabs from the desks on which the vaccine nebulizer was set, mask samples from participants, and blood samples of nurses who administered the inoculation in the clinical trials. The viral load of adenovirus type-5 vector in the samples and the antibody levels against the wild-type severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strain in serum were detected.
Results
Only one (4.00%) air sample collected before initiation of vaccination was positive and most air samples collected during and after vaccination were positive (97.96%, 100%, respectively). All nurses in trial A showed at least 4-fold increase of the neutralizing antibody against SARS-CoV-2 after initiation of the study. In trial B, the proportion of positive mask samples was 72.97% at 30 minutes after vaccination, 8.11% at day 1, and 0% at days 3, 5, and 7.
Conclusions
Vaccination with the orally aerosolized Ad5-nCoV could result in some spillage of the vaccine vector viral particles in the environment and cause human exposure.
Clinical Trials Registration. NCT04840992 and NCT05303584.
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