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Extracting uranium from water bodies is urgently needed whether from a waste nuclear resource utilization or a new energy exploration perspective. Herein, a novel robust hierarchical porous CAP membrane was fabricated from the nucleophilic condensation of phenolphthalein and 2,6-difluorobenzonitrile, followed by classical amidoximation and nonsolvent-induced phase separation (NIPS) methods. Fast uranium uptake kinetics with sorption equilibrium at a mere 12 h was demonstrated, and the uranium uptake capacity was found to be 499 mg g−1. The significant improvement in uranium enrichment performance was probably endowed by the outstanding hydrophilic surface and the hierarchical pores throughout the cross-sectional CAP membrane. Meanwhile, it was confirmed that the CAP molecular backbone may endure polymer degradation during amidoximation, and the amount of hydroxylamine used should be strictly controlled. The sorption mechanism was explored, and practical testing experimentally indicated the excellent desorption, reusability and selectivity properties of the CAP membrane. Overall, the easy processability, robustness and outstanding uranium sorption performance made the CAP membrane an ideal candidate for uranium enrichment from water bodies. [ABSTRACT FROM AUTHOR]

Metal-free photocatalysis that produces reactive oxygen species (ROS) shows significant promising applications for environmental remediation. Herein, we constructed iodine-doped carbon nitride (I-CN) for applications in the photocatalytic inactivation of bacteria and the heterogeneous Fenton reaction. Our findings revealed that I-CN demonstrates superior photocatalytic activity compared to pure CN, due to enhanced light adsorption and a narrowed band gap. Antibacterial tests confirmed that I-CN exhibits exceptional antibacterial activity against both Escherichia coli and Staphylococcus aureus. The results showed that I-CN effectively generates superoxide radicals and hydroxyl radicals under light irradiation, resulting in enhanced antibacterial activity. In addition, I-CN can also be applied for a heterogeneous photo-Fenton-like reaction, achieving a high performance for the degradation of sulfamethoxazole (SMX), a typical antibiotic, via the photocatalytic activation of peroxymonosulfate (PMS). These results shed new light on the fabrication of metal-free nanozymes and their applications for disinfection and water decontamination. [ABSTRACT FROM AUTHOR]

[Objective] To investigate the hadal sediments main type, geochemical characteristics and formation in the Challenger Deep of the southern Mariana Trench, [Methods] the mineralogical and geochemical analysis were uesd to study the sediments and altered basalt from north slope (overlying plate) and axis to the south slope (subduction plate) at the Challenger Deep of the Mariana Trench. [Results and Conclusions] The hadal sediments can be divided into four types: red deep-sea clay, siliceous sediments, micromanganese-rich sediments, and calcareous sediments. The red deep-sea clay is the most common type of hadal sediment, which contribute the most to subducted sediments. Major and trace element geochemical characteristics are similar to those of altered basalt of the oceanic crust, which imply that red clay is mainly derived from the basalt alteration of the subducted and overlying plates, rather than the volcanic and terrestrial inputs. Moreover, intensified organic matter diagenesis has an important influence on the geochemical properties of the hadal sediments, which is the main reason the Challenger Deep sediments have lower rare earth elements and enrich more micromanganese nodules than the adjacent deep-sea sediments. [ABSTRACT FROM AUTHOR]

In order to obtain the quality information of Taishan black tea and provide data support for the establishment of assessment criteria for quality control of Taishan black tea, in this study, 45 samples of Taishan black tea were collected during the summer to investigate their quality characteristics. The results showed that the Taishan black tea typically exhibited a dark-brown, curly appearance and a uniform texture. The tea soup displayed a bright orange-red color. The tea was mainly described as having a fruity aroma, followed by a caramel flavor, sweet aroma, flowery flavor, and clean aroma, with a strong and enduring fragrance. The taste profile was mostly heavy and mellow or heavy and strong, with fewer samples exhibiting slight bitterness and astringency. The tea leaves were characterized by a reddish-auburn color, a soft texture, and an even appearance. The main biochemical components of the Taishan black tea fell within the following ranges: water extracts (38.65–43.35%), free amino acids (1.41–3.45%), tea polyphenols (9.80–15.05%), catechins (6.11–9.03%), and caffeine (1.65–3.05%). The phenolic acid/amino acid ratio was 2.31–6.65%. Catechins and tea polyphenols emerged as critical indicators influencing taste quality, followed by amino acids, water extracts, and caffeine. The aroma analysis identified common compounds, such as 3-methyl-butanal, 2-methyl-butanal, decanal, 2-methyl-propanal, 1-octen-3-ol, and β-ionone, in most samples. These compounds exhibited relatively high contents and high odor activity values, making them the primary contributors to the tea's aroma. This investigation into the quality of Taishan black tea offers valuable scientific insights, providing a foundation for the standardization of Taishan black tea's quality. [ABSTRACT FROM AUTHOR]

Stereotyping towards the second language accent of second language learners is extensively seen even when the content of learner speech can be understood. Previous studies reported conflicting results on accent perception by speakers of second languages, especially among homogenous learners. In this paper, we conducted a survey and two experiments to test whether Mandarin-speaking advanced learners of English may give harsher accent ratings to their fellow learners than to Standard American English speakers. The survey was designed to understand the L2 listeners' beliefs about accented speech. In Experiment 1, participants rated short audio recordings of L2 learner' and Standard American English speech; in Experiment 2, they did the same in a more detailed word-in-sentence accent rating task. Results showed a markedly high level of perceived L2 accentedness for several learner speech stimuli despite good intelligibility, especially for the strongly-accented Cantonese passage and for specific vowel and consonant types. The findings reveal the existence of native-speakerism in China and highlight existing accent stereotypes. Implications for policymaking and language teaching are discussed. [ABSTRACT FROM AUTHOR]

A dual-channel glucose sensor, based on surface plasmon resonance (SPR), is proposed and experimentally confirmed. The proposed sensor is composed of a single-mode fiber (SMF) sandwiched by two multimode fibers (MMFs). The gold is coated on the cylindrical cladding surface of the optical fiber as a sensing channel to measure the glucose concentration. The other channel is composed of polydimethylsiloxane (PDMS) and gold film to sense the ambient temperature. It has been experimentally verified that the glucose sensor’s concentration sensitivity and temperature sensitivity can reach 2.99 nm/% and −3.580 nm/°C, respectively. The proposed sensor, possessing advantages such as compact structure, excellent sensing performance and the ease of fabrication, has potential applications in biology, chemistry, medicine, etc. [ABSTRACT FROM AUTHOR]

Heterogeneous catalytic hydrogenation reactions are of great significance in chemical industry. In this work, ultrasmall Pd nanoparticles (NPs) supported on porous g-C3N4 nanosheets (Pd/CN) have been prepared for efficient hydrogenation reactions. The special structure of the catalytic metal–semiconductor heterojunction not only stabilize the Pd NPs but also improve their electronic activation. In addition, the high surface area of Pd/CN provides a large numbers of adsorption sites for styrene and H2. As a result, the optimized Pd/CN-0.5 nanocomposites achieved 100% conversion of styrene in 60 min under mild conditions. [ABSTRACT FROM AUTHOR]