Latest ArticlesTo develop efficient sensitizers for dye-sensitized solar cells (DSSCs), we recently reported doubly concerted companion (DCC) dye XW83 with a wrapped porphyrin sub-dye unit linked to an organic sub-dye unit through a flexible chain, which exhibits panchromatic absorption and excellent anti-aggregation ability. To further improve the absorption, we herein report XW87 and XW88 by inserting an ethynyl group into the organic sub-dye unit of XW83 near the donor and acceptor, respectively. For the corresponding organic dyes Z3 and Z4, the introduced ethynyl group improves their absorption, but induces aggravated charge recombination, leading to lowered power conversion efficiencies (PCEs). Similar to the organic dyes, the introduced ethynyl group improves the absorption of DCC dyes XW87 and XW88 as well. In addition, the ethynyl group near the acceptor of the organic sub-dye unit can be well protected by the long wrapping chains from the porphyrin unit. As a result, XW88 affords the highest JSC (21.84 mA/cm2), VOC (782 mV) and PCE (12.2%) among the DCC dyes. These results provide an effective method for developing efficient DSSC dyes by inserting an ethynyl group at a suitable position of a DCC dye.
Antibiotic abuse now poses a grave threat to global ecology and bestirs public concerns about the residue issue in daily necessities. The traceability measurements along supply chain or logistic circulation have become increasingly essential given the labile nature of diverse synthetic residuals on site. In an attempt to answer this urgency, here a miniaturized fluorometric aptasensor prototype was contrived that catered to the point-of-care screening norm for two typical additives: chloramphenicol and enrofloxacin. The key target-indicating module worked in vitro based on the competitive binding-induced fluorescence recovery of fluorescein-labeled aptamers, which were photobleached beforehand in the format of double helix on burlike nanogold carriers. The “prickly” geometry of the latter not just enriched the capture probes at preferentially substrate-accessible spires; but also contributed to a tip-enhanced surface plasmon effect, sensitizing the signal-on during the duplex dissociation even at nanomolar threshold of the analytes. On the other hand, to encompass a full portable, a set of optical devices were mounted within a 3D-printed cartridge (adaptor) to converge the light beam and route it towards the detector, for which the smartphone camera came up in handy with a home-developed App for calibrating the emissive brightness. Enlightened by the high-dynamic-range compression, an imaging diagnostic algorithm was built in to grid and digitize each slide in the album for augmented detection performance. Thus, a novel bio-to-silico integration was invented that capable of in situ rapid reporting on the antibiotic presence with high sensitivity and selectivity. Further field practices in spiked milk on sales proved the precision and rudimentary feasibility of the well-assembled model of appliance, thus holding nice prospects in nonexpert (e.g., family and local community) utilities for foodborne antibiotic identification.
Sulfydryl-contained (-SH) substances including hydrogen sulfide (H2S), cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) play crucial roles in living systems, and their variations are closely associated with various diseases. Herein, we developed a near-infrared intramolecular charge transfer (ICT) based fluorescent probe Y-NBD, achieving detection of Cys/Hcy and H2S with different fluorescent signals (green-red for Cys/Hcy, red for H2S), large Stokes shifts (~100/105 nm or 191 nm) and high signal-background-ratio, but not responding to GSH. Y-NBD was successfully applied to image exogenous/endogenous Cys/Hcy and H2S in various living cancer cells (HeLa, A549, and HepG2) and in zebrafish. It not only visualized the transformation pathway of several thiols in HepG2 cells but also verified that the intestine is the main site for the activation and metabolism of Y-NBD in zebrafish, as well as realized to evaluate the degree of drug-induced liver injury. This work provides a promising tool for imaging Cys/Hcy and H2S in living systems and shows great potency in evaluating drug-induced liver injury and its treatment.
The present study reported fabrication of novel carbon quantum dots-MnFe2O4@ZIF-8 (CQDs-MFO@ZIF-8) by using co-precipitation hydrothermal method for activation of peroxydisulfate (PDS) to degrade bisphenol A (BPA), one of important emerging organic pollutants in water environment. CQDs-MFO@ZIF-8 served as a highly efficient thermal activated PDS catalyst with high catalytic degradation efficiency, reusability and stability. The catalyst achieved almost completely removal of 20.0 mg/L BPA within 5.0 min, and the degradation efficiency remained higher than 83% after 5 consecutive cycles. Free radicals (•OH, SO4•− and •O2−) and non-free radicals (1O2) were generated in the thermal PDS-activation system, in which singlet oxygen (1O2) played a dominant role in the degradation of BPA. The potential toxicity of BPA degradation intermediates was analyzed upon the culture of E. coli and Chlorella sorokiniana by using Ecological Structure-Activity Relationship Model (ECOSAR) program. The catalytic performances of BPA degradation by CQDs-MFO@ZIF-8 were evaluated for treatment of different practical water samples to further verify the feasibility of practical applications. This study provides proof-in-concept demonstration of new nanomaterials for enhanced catalytic water decontamination.
Presented here is a one-pot strategy starting from rationally designed macrocyclic precursors for the diverse construction of sophisticated ultracycles. The type and amount of the base were found to significantly influence the macrocyclization outcome. The use of 4.0 equiv. CsF resulted in ultracycles of both types A and B while the presence of CsF larger than 6.0 equiv. produced only type B ultracycles. Existence of anion template increased the total yields and affected the distribution of the ultracycles. The ultracycles can accommodate large organic dicarboxylates anions via multiple anion–π and hydrogen bonds, and show selectivity to the size-matched heptanedioate (C72−). Based on all possible species and relevant equilibrium constants as well as material and charge balances, a numerical iterative algorithm was developed and applied to fit the association constants of B2H with dicarboxylates from glutarate (C52−) to octanedioate (C82−), which gave association constants up to 103 L/mol.
The dynamic RNA modifications have been viewed as new posttranscriptional regulator in modulating gene expression as well as in a broad range of physiological processes. N1-methyladenosine (m1A) is one of the most prevalent modifications existing in multiple types of RNAs. In-depth investigation of the functions of m1A requires the site-specific assessment of m1A stoichiometry in RNA. Herein, we established a demethylase-assisted method (DA-m1A) for the site-specific detection and quantification of m1A in RNA. N1-methyl group in m1A could result in the stalling of reverse transcription at m1A site, thus producing the truncated cDNA. E. coli AlkB is a demethylase that can demethylate m1A to produce adenine in RNA, thus generating full-length cDNA from AlkB-treated RNA. Evaluation of the produced amounts of full-length cDNA by quantitative real-time PCR can achieve the site-specific detection and quantification of m1A in RNA. With the DA-m1A method, we examined and successfully confirmed the previously well-characterized m1A sites in various types of RNAs with low false positive rate. In addition, we found that the level of m1A was significantly decreased at the bromodomain containing 2 (BRD2) mRNA position 1674 and CST telomere replication complex component 1 (CTC1) mRNA position 5643 in human hepatocellular carcinoma tissues. The results suggest that these two m1A sites in mRNA may be involved in liver tumorigenesis. Taken together, the DA-m1A method is simple and enables the rapid, cost-effective, and site-specific detection and quantification of m1A in RNA, which provides a valuable tool to decipher the functions of m1A in human diseases.
Commercial V2O5-based catalysts have been successfully applied in NH3 selective catalytic reduction (NH3-SCR) of NOx from power stations, but their poor alkali-resistance restrains the wider application in nonelectrical industries. In this study, NOx reduction against alkali poisoning over V2O5/TiO2 is greatly improved via Ce(SO4)2 modification. It has been originally demonstrated that Ce4+–SO42− pair sites play crucial roles in improving NOx reduction against alkali poisoning over V2O5/TiO2 catalysts. The strong interaction between V species and Ce sites of Ce4+–SO42− pairs triggers the reaction between NH4+species and gaseous NO via Eley-Rideal (E-R) reaction pathway. After K-poisoning, the SO42− sites of Ce4+–SO42− pairs as protective sites strongly bond with K and thus maintain the high reaction efficiency via the E-R reaction pathway. This work demonstrates an effective strategy to enhance NOx reduction against alkali poisoning over catalysts via constructing Ce4+–SO42− pair sites, contributing to developing alkali-resistant SCR catalysts for practical application in nonelectrical industries.
Increasing use of silver in various fields has caused Ag+ pollution in water environment, taking great threats to people's health. As a consequence, establishing rapid and reliable methods for sensitive determination of Ag+ is of great significance. Fluorescent (FL) sensors based on carbon dots (CDs), an excellent carbonaceous nanomaterial with strong and stable fluorescence, have absorbed extensive attentions in analysis of pollutants due to its advantages of carbon sources being readily available, low cost, easy operation and fast response. Moreover, ion-imprinting is a better way to increase the selectivity of the proposed method. Present work described an effective method for the sensitive measurement of silver ion in water samples in combination with magnetic ion-imprinted solid phase extraction and CDs based fluorescent sensor, which took full advantages of easy separation and high enrichment of magnetic solid phase extraction, high selectivity of ion-imprinting technology, and sensitivity and rapid response of fluorescent sensor from CDs. Sulfur-doped CDs derived from dithizone and magnetic ion-imprinted nanomaterial were prepared, and characterized with Fourier transform infrared spectroscopy and transmission electron microscope, etc. Magnetic Ag+ imprinted nanomaterial based solid phase extraction was employed for separating and enriching Ag+ from water samples. The significant parameters were optimized in detail. Under the optimal conditions, the proposed method provided good linearity in the range of 0.01–0.4 µmol/L and low detection limit of 3 nmol/L. The reliability of the proposed method was validated with real water samples, and the results demonstrated that the proposed method was simple, robust, selective and sensitive detection tool for Ag+ in real water samples.
In the face of multiple challenges brought by the changes of global climate and environment, developing clean energy and updating green energy storage equipment are important ways to achieve carbon peak and carbon neutrality. Aqueous batteries have become a research hotspot due to their advantages of using the multivalent charge carrier, high ionic conductivity, environmental friendliness and cost effectiveness. In this work, the Cu2Se@C (Cu2Se coated on carbon clothes) thin film with a three-dimensional braided structure is fabricated by a simple electrochemical deposition method for Cu2+ storage for the first time. Compared with the commercial Cu2Se powder, the well-designed Cu2Se@C film shows enhanced specific capacity (640 mAh/g at 0.5 A/g) and rate performance (542 mAh/g at 5 A/g) as well as superior cycling stability (82.7% capacity retention after 1000 cycles at 1 A/g). The Cu2+ storage mechanism of the Cu2Se@C electrode is based on a reversible phase transition process of Cu2Se ↔ Cu2-xSe ↔ CuSe ↔ CuSe2. In kinetic characteristic analysis, the Cu2Se@C electrode demonstrates faster Cu2+ diffusion in discharge process than charge process resulting from the phase transition and the variation of interplanar spacing. This work highlights a facile one-piece design strategy and opens a new gateway for the exploration of advanced aqueous energy storage systems.
Nanoplastics (NPs) in aqueous environment have become a category of emerging pollutants on account of their potential risks to both human health and environment. The detection of NPs is a great challenge due to the lack of sensitive and selective sensing materials with fast response time and wide sensing range of particle sizes. Herein, a Tb-based coordination polymer has been synthesized for luminescent detection of nanopolystyrene with different particle sizes in aqueous solutions, showing a low limit of detection, fast response time within 10 s and high selectivity in the presence of other plastics. The “turn-on” sensing mechanism is studied in detail. This work provides a facile method for the fast detection of NPs.
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