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A functionalization of benzylic C(sp3)–H bonds was established through a mild metal-free intramolecular lactonization protocol in the presence of DDQ/ tert -butyl nitrite as photocatalysts, allowing practical and low-cost access to a series of phthalide products in moderate to excellent yields. Compared with many existing methodologies, this visible-light-driven process exhibits an excellent substrate scope and fascinating features, including the formation of water as the sole byproduct, an abundant and green energy source, commercially available catalysts, and room-temperature reaction. Finally, detailed mechanistic investigations clearly revealed the role of the photocatalysts and molecular oxygen. [ABSTRACT FROM AUTHOR]

The determination of the aflatoxin B1 (AFB1) content has received widespread attention in the context of food safety, which is a global public health issue. Accordingly, a label-free and turn-on fluorescent AFB1 determination method is developed herein with an ss-DNA aptamer as the recognition element, 4, 4-(1E,1E)-2, 2-(anthracene-9, 10-diyl) bis(ethene-2, 1-diyl) bis(N, N, N-trimethylbenzenaminium iodide) (DSAI) as the aggregation-induced emission (AIE) fluorescent probe, and single-walled carbon nanohorns (SWCNHs) as the selective part with a fluorescence quenching effect. In the presence of AFB1, the AFB1-specific aptamer undergoes a structural transformation and switches from being a random helix to a folded structure. DSAI's fluorescence is protected as a result of the resistance of the transformed aptamer adsorbed on the SWCNHs' surface. Because DSAI's fluorescence is not quenchable, the fluorescence intensity is calculated as a function of the AFB1 concentration. By simply mixing DSAI, aptamer, AFB1 samples, and SWCNHs, the method can be carried out in 2 h, with a limit of detection (LOD) of 1.83 ng/mL. It has a high selectivity in the presence of other mycotoxins, and its performance is confirmed in soybean sauce with a known concentration of AFB1. The LOD was 1.92 ng/mL in the soy sauce samples and the recovery ranged from 95 to 106%, implying that the presented aptasensor has great potential for food analysis. [ABSTRACT FROM AUTHOR]

Streamer behaviors, related to discharge patterns, can determine the distribution of active species, which play an important role in the applications of the plasma jet. In this article, petal‐like patterns formed on the substrate are observed for the first time downstream of an argon plasma jet. The penta‐petalous pattern is taken as an example to discuss the pattern formation mechanism, which results from two positive discharges (Dp1 and Dp2) and one negative discharge (Dn) in every voltage cycle. Fast photography is implemented to reveal the complicated streamer dynamics of Dp2. Results indicate that Dp2 with a low Q undergoes a stripe phase, a homogeneous phase, and a branch phase. The complicated streamer dynamics of Dp2 are analyzed based on optical emission spectra. [ABSTRACT FROM AUTHOR]

In this experimental research, a label-free sensing strategy is developed and employed to detect adenosine triphosphate with utilization of aptamers, including exonuclease I and SYBR Gold. The conformation of aptamers bonding to the specific target molecule (ATP) is transformed into an antiparallel G-quadruplex structure from a random coil. Afterwards, considering the unfolded aptamers are the preferred substrates for exonuclease I, the addition of exonuclease I is used so as to digest unfolded aptamers in the mixture in a selective manner. In the follow-up study, in order to strengthen the fluorescence intensity, SYBR Gold is applied as a fluorescent probe. The aptasensor presents the features of high selectivity against adenosine triphosphate and the low detecting limit of concentrations (39.2 nM). In order to verify the validation of experimental procedures and the practical application of the aptasensor, the detection of adenosine triphosphate for human serum samples is performed with satisfactory success. The recovery result with the range of 93.8%–108.1% is desirable and suggests that the designed approach is applicable. The outcomes of the cellular adenosine triphosphate assay manifest that the level of adenosine triphosphate concentrations in cell extracts can be monitored without the interference of other substances in the cells. Subject to its advantageous benefits (cost-effective, easiness, rapidity, and extraordinary selectivity), the designed approach has a promising implication for adenosine triphosphate detection in the research domain of bioanalytical science and biology. Graphical Abstract [ABSTRACT FROM AUTHOR]

As the main consumers of bacteria and fungi in farmed soils, protists remain poorly understood. The aim of this study was to explore protist community assembly and ecological roles in soybean fields. Here, we investigated differences in protist communities using high-throughput sequencing and their inferred potential interactions with bacteria and fungi between the bulk soil and rhizosphere compartments of three soybean cultivars collected from six ecological regions in China. Distinct protist community structures characterized the bulk soil and rhizosphere of soybean plants. A significantly higher relative abundance of phagotrophs was observed in the rhizosphere (25.1%) than in the bulk soil (11.3%). Spatial location (R 2 = 0.37–0.51) explained more of the variation in protist community structures of soybean fields than either the compartment (R 2 = 0.08–0.09) or cultivar type (R 2 = 0.02–0.03). The rhizosphere protist network (76 nodes and 414 edges) was smaller and less complex than the bulk soil network (147 nodes and 880 edges), indicating a smaller potential of niche overlap and interactions in the rhizosphere due to the increased resources in the rhizosphere. Furthermore, more inferred potential predator-prey interactions occur in the rhizosphere. We conclude that protists have a crucial ecological role to play as an integral part of microbial co-occurrence networks in soybean fields. [ABSTRACT FROM AUTHOR]

Main observation and conclusion: One near‐infrared (NIR) luminescent octanuclear Zn(II)‐Yb(III) complex [Zn6Yb2L4(OAc)2(DMF)EtOH] (1) was obtained from a new multidentate Schiff base ligand. It exhibits interesting luminescent sensing activity to antibiotics, in particular to nitrofuran antibiotics (NFAs) with high sensitivity due to the inner filter effect. The NIR luminescence quenching constants and limits of the detection of the complex towards NFAs are 2.9 × 104—5.5 × 104 L/mol and 1.27—2.38 μmol/L, respectively. Its high luminescence sensitivity to NFAs is not changed with the existence of other antibiotics. [ABSTRACT FROM AUTHOR]

One 18-metal Eu(III) nanoring (size: 1.0 × 2.7 × 2.7 nm) was constructed as a rapid ratiometric fluorescent probe for the detection of dipicolinic acid with high sensitivity and selectivity, by using two types of polydentate organic ligands. [ABSTRACT FROM AUTHOR]

One NIR luminescent 14-metal Nd(III) nanoring (1, molecular size: 1.0 × 2.2 × 2.6 nm) was obtained from a rigid tridentate ligand, which can absorb and transfer light energy to the Nd(III) ions. 1 shows interesting luminescence sensing activity to antibiotics, in particular to NFAs with high sensitivity due to the inner filter effect. The quenching constants and the limits of detection of 1 to NFAs are 1.05 × 104 M−1–2.33 × 104 M−1 and 3.05 μM–6.75 μM, respectively. The high fluorescence sensitivities of 1 to NFAs are not changed by the existence of other antibiotics. It also exhibits high sensitivity in the luminescent detection of NFAs contained in real antibiotic drugs. [ABSTRACT FROM AUTHOR]

Summary of main observation and conclusion: One six‐metal Zn(II)‐Yb(III) complex [Zn2Yb4L2(OAc)10(OH)2(CH3OH)2] (1) was constructed from Schiff base ligand bis(3‐methoxysalicylidene)ethylene‐1,2‐phenylenediamine (H2L). 1 shows a nanoscale rectangular structure with dimensions of approximately 0.8 nm × 1.1 nm × 2.8 nm. Excited by ligand‐centered absorption bands, 1 shows typical near‐infrared emission of Yb3+ ion. Interestingly, 1 exhibits lanthanide luminescent response towards metal ions, especially to Cd2+ at ppm level. [ABSTRACT FROM AUTHOR]

Two 14-metal lanthanide nanorings [Ln14(HL)2L20(DMF)8(H2O)8] (Ln = Nd(1) and Gd(2)) were constructed from a tridentate ligand. 1 displays NIR luminescence sensing properties towards metal cations and anions, especially Cu2+, Co2+, H2PO4− and F− at a ppm level. [ABSTRACT FROM AUTHOR]

An efficient synthesis of functionalized 3-acyl-2 H -indazoles via visible-light-induced self-catalyzed energy transfer was developed. This method utilized a self-catalyzed energy transfer process between 2 H -indazoles and α-keto acids, offering advantages like absence of photosensitizers, metal catalysts, and strong oxidants, broad substrate compatibility, and operational simplicity under mild conditions.

One 18-metal Eu(iii) nanoring (size: 1.0 × 2.7 × 2.7 nm) was constructed as a rapid ratiometric fluorescent probe for the detection of dipicolinic acid with high sensitivity and selectivity, by using two types of polydentate organic ligands.

One NIR luminescent 14-metal Nd(iii) nanoring (1, molecular size: 1.0 × 2.2 × 2.6 nm) was obtained from a rigid tridentate ligand, which can absorb and transfer light energy to the Nd(iii) ions. 1 shows interesting luminescence sensing activity to antibiotics, in particular to NFAs with high sensitivity due to the inner filter effect. The quenching constants and the limits of detection of 1 to NFAs are 1.05 × 104 M-1-2.33 × 104 M-1 and 3.05 μM-6.75 μM, respectively. The high fluorescence sensitivities of 1 to NFAs are not changed by the existence of other antibiotics. It also exhibits high sensitivity in the luminescent detection of NFAs contained in real antibiotic drugs.

Two d-4f complexes [Zn 2 NdL 2 (OAc) 2 ]·OH ( 1 ) and [Cd 3 Sm 3 L 3 (OAc) 6 (OH) 3 ] ( 2 ) with a designed Schiff base ligand N , N '-bis(3-methoxysalicylidene)(binaphthyl)-1,4-diamine (H 2 L) were synthesized. The Schiff base ligands coordinate with metal ions by μ 2 (η 1 :η 2 :η 1 :η 1 :η 2 :η 1 ) and μ 2 (η 1 :η 2 :η 1 :η 1 :η 2 :η 1 ) modes in the complexes, which show typical lanthanide emissions. The triangular Cd-Sm complex 2 shows both visible and NIR luminescent responses to nitrobenzene explosive 2,4,6-trinitrophenol (PA).

One Zn-Nd complex [Zn 2 Nd 4 L 2 (OAc) 10 (OH) 2 (CH 3 OH) 2 ] ( 1 ) was synthesized from Schiff base ligand bis(3-methoxysalicylidene)ethylene-1,2-phenylenediamine (H 2 L). 1 shows nanoscale rectangular structure with sizes of about 0.8 × 1.1 × 2.8 nm. 1 exhibits typical near-infrared luminescence of Nd(III) under the excitation of UV-visible light. Further study shows that the complex displays luminescent response behavior to anions and nitro explosives, especially with high sensitivity to H 2 PO 2 - and 2,4,6-trinitrophenol., (Copyright © 2020 Liu, Yang, Ma, Liu, Shi, Niu and Schipper.)