Construction of eco-friendly dual carbon dots ratiometric fluorescence probe for highly selective and efficient sensing mercury ion.

In present work, blue carbon dots (b-CDs) were derived from ammonium citrate and guanidine hydrochloride, and red carbon dots (r-CDs) were stemmed from malonate, ethylenediamine and meso­tetra (4-carboxyphenyl) porphin based on facile hydrothermal method. Eco-friendly ratiometric fluorescence probe was innovatively constructed to effectively measure Hg2+ utilizing b-CDs and r-CDs. The developed probe displayed two typical emission peaks at 450 nm from b-CDs and 650 nm from r-CDs under the excitation at 360 nm. Mercury ion has strong quenching effect on the fluorescence intensity at 450 nm due to the electron transfer process and the fluorescence change at 450 nm was used as the response signal, whereas the fluorescence intensity at 650 nm kept unchangeable which resulted from the chemical inertness between Hg2+ and r-CDs, serving as the reference signal in the sensing system. Under optimal circumstances, this probe exhibited an excellent linearity between the fluorescence response values of ΔF450/F650 and Hg2+ concentrations over range of 0.01-10 µmol/L, and the limit of detection was down to 5.3 nmol/L. Furthermore, this probe was successfully employed for sensing Hg2+ in practical environmental water samples with satisfied recoveries of 98.5%-105.0%. The constructed ratiometric fluorescent probe provided a rapid, environmental-friendly, reliable, and efficient platform for measuring trace Hg2+ in environmental field.

Sensitive visual detection of norfloxacin in water by smartphone assisted colorimetric method based on peroxidase-like active cobalt-doped Fe3O4 nanozyme.

Norfloxacin is widely used owing to its strong bactericidal effect on Gram-negative bacteria. However, the residual norfloxacin in the environment can be biomagnified via food chain and may damage the human liver and delay the bone development of minors. Present work described a reliable and sensitive smartphone colorimetric sensing system based on cobalt-doped Fe3O4 magnetic nanoparticles (Co-Fe3O4 MNPs) for the visual detection of norfloxacin. Compared with Fe3O4, Co-Fe3O4 MNPs earned more remarkably peroxidase-like activity and TMB (colorless) was rapidly oxidized to oxTMB (blue) with the presence of H2O2. Interestingly, the addition of low concentration of norfloxacin can accelerate the color reaction process of TMB, and blue deepening of the solution can be observed with the naked eye. However, after adding high concentration of norfloxacin, the activity of nanozyme was inhibited, resulting in the gradual fading of the solution. Based on this principle, a colorimetric sensor integrated with smartphone RGB mode was established. The visual sensor exhibited good linearity for norfloxacin monitoring in the range of 0.13-2.51 µmol/L and 17.5-100 µmol/L. The limit of visual detection was 0.08 µmol/L. In the actual water sample analysis, the spiked recoveries of norfloxacin were over the range of 95.7%-104.7 %. These results demonstrated that the visual sensor was a convenient and fast method for the efficient and accurate detection of norfloxacin in water, which may have broad application prospect.

Dual COF functionalized magnetic MXene composite for enhancing magnetic solid phase extraction of thiophene compounds from oilfield produced waters prior to GC-MS/MS analysis.

In this study, a novel COFTABT@COFTATp modified magnetic MXene composite (CoFe2O4 @Ti3C2 @COFTABT@COFTATp) was synthesized by Schiff base reaction and irre-versible enol-keto tautomerization, and employed to establish a sensitive monitoring method for six thiophene compounds in oilfield produced water samples based on magnetic solid-phase extraction (MSPE) prior to gas chromatography coupled with a triple quadruple mass spectrometer (GC-MS/MS). The designed magnetic materials exhibited unexpected enrichment ability to target thiophene compounds and achieved good extraction efficiencies ranging from 83 % to 98 %. The developed MSPE/GC-MS/MS method exhibited good linearity in the range of 0.001-100 µg L-1, and obtained lower limits of detection ranging from 0.39 to 1.9 ng L-1. The spiked recoveries of thiophene compounds obtained in three oilfield produced water samples were over the range of 96.26 %-99.54 % with relative standard deviations (RSDs) less than 3.7 %. Notably, benzothiophene, 4-methyldibenzothiophene and 4,6-dimethyldibenzothiophene were detected in three oilfield-produced water samples. Furthermore, the material still kept favorable stability after six recycling experiments. The adsorption kinetics, adsorption isotherms as well as adsorption thermodynamics of thiophene compounds were investigated in detail to provide insight into the mechanisms. Overall, the present work contributed a promising strategy for designing and synthesizing new functionalized materials for the enrichment and detection of typical pollutants in the environment.

A colorimetric sensor based on multiple elements doped carbon dot nanozyme for rapid detection of 1-naphthol in human urine samples.

The residual carbaryl in crops can cause serious damage to the human kidney and nervous system after entering the human body, which may be metabolized to 1-naphthol (1-NAP) and excreted through urine. 1-NAP is often used as the biomarker for carbaryl exposure, so the intake or leakage of carbaryl can be monitored by detecting the concentration of 1-NAP. Herein, Co, N, P ternary co-doped carbon dots (CoNP-CDs) derived from vitamin B12 were synthesized by a facile hydrothermal method. CoNP-CDs exhibited oxidase-like activity and excellent peroxidase-like activity, which was attributed to the Fenton-like reaction of Co2+/Co3+ and the presence of pyrrole N and P elements, which together provided multiple active sites for chromogenic substrates. Due to the dual enzyme-like activity of CoNP-CDs, hydroxyl radicals (OH) and superoxide radicals (O2-) were generated during the catalytic process, which could rapidly oxidize colorless 3,3',5,5'-tetramethyl benzidine (TMB) to blue oxidation products (oxTMB). The α-carbon in 1-NAP can be attacked by OH, and the catalytic oxidation process of TMB can be inhibited by the consumption of OH, so that the blue color of the solution became lighter. Based on this principle, a smartphone-assisted colorimetric sensing platform was constructed for the detection of 1-NAP, and which resulted in a linear range of 1.07-37.3 µM and a visual detection limit of 0.68 µM. Moreover, the colorimetric sensing system showed satisfactory recoveries in the detection of human urine samples. The colorimetric sensing system owned the advantages of fast response, strong selectivity and simple operation, and provided a potential strategy for the on-site detection of 1-NAP.

Covalent organic framework-functionalized magnetic MXene nanocomposite for efficient pre-concentration and detection of organophosphorus and organochlorine pesticides in tea samples before gas chromatography-triple quadrupole mass spectrometry analysis.

In this study, a hydrophobic covalent organic framework-functionalized magnetic composite (CoFe2O4@Ti3C2@TAPB-TFTA) with a high specific area with 1,3,5-tris(4-aminophenyl)benzene (TAPB) and 2,3,5,6-tetrafluoroterephthalaldehyde (TFTA) was designed and synthesized through Schiff base reaction. An efficient magnetic solid-phase extraction method was established and combined with gas chromatography-triple quadrupole mass spectrometry to sensitively determine 10 organochlorine and organophosphorus pesticides in tea samples. The established method exhibited good linearity in the range of 0.05-120 µg/L and had low limits of detection (0.013-0.018 µg/L). The method was evaluated with tea samples, and the spiked recoveries of pesticides in different tea samples reached satisfactory values of 85.7-96.8%. Moreover, the adsorption of pesticides was spontaneous and followed Redlich-Peterson isotherm and pseudo-second-order kinetic models. These results demonstrate the sensitivity, effectiveness, and reliability of the proposed method for monitoring organochlorine and organophosphorus pesticides in tea samples, providing a preliminary basis for researchers to reasonably design adsorbents for the efficient extraction of pesticides.

Enrichment and detection of polycyclic aromatic hydrocarbon in tea and coffee using phenyl-functionalized NiFe2O4@Ti3C2TX based magnetic solid-phase extraction.

Polycyclic aromatic hydrocarbons (PAHs) are commonly found in various environmental matrices and have received significant attention due to their toxic effects on ecosystems and environmental health. In this study, a specific magnetic composite material derived from MXene, known as phenyl-functionalized NiFe2O4@Ti3C2TX, was designed and synthesized using a simple method. This composite material was used to develop an effective magnetic solid-phase extraction (MSPE) method for enriching trace polycyclic aromatic hydrocarbons (PAHs) in tea and coffee samples. The eluted PAHs were analyzed via gas chromatography-tandem mass spectrometry. Under optimal conditions, this method exhibited excellent linear relationships for 16 PAHs within the ranges of 0.001-25 and 0.0005-25 µg/L, with correlation coefficients exceeding 0.9979. The limits of detection for the target PAHs ranged from 0.1 to 0.3 ng/L. The effectiveness of the proposed method was evaluated by analyzing tea and coffee samples, and the satisfactory spiked recoveries of PAHs ranged from 84.5% to 112.6%.

Construction of nitrogen-doped carbon dots-based fluorescence probe for rapid, efficient and sensitive detection of chlortetracycline.

Antibiotics are widely used in clinical medicine due to their excellent antibacterial abilities. As typical emerging pollutants, their misuse can lead to excess antibiotics entering the environment, causing antimicrobial resistance and leading to serious health problems via food chain. Herein, a nano-fluorescent probe based on nitrogen-doped carbon dots (N-CDs) was constructed for the sensitive detection of chlortetracycline (CTC). N-CDs with stable fluorescence were synthesized by hydrothermal method using alizarin red and melamine as raw materials. The N-CDs exhibited significant independence to excitation wavelength. The fluorescence of N-CDs was significantly quenched by CTC ascribing to the fluorescence resonance energy transfer mechanism. The concentration of N-CDs, solution pH and incubation time were optimized to obtain the optimal detection parameters. Under optimal conditions, CTC exhibited excellent linearity over the range of 20-1200 µg/L, and the detection limit was 8.74 µg/L. The method was validated with actual water samples and achieved satisfied spiked recoveries of 97.6-102.6%. Therefore, the proposed method has significant application value in the detection of CTC in waters.

Highly sensitive passive sampling of new pollutants in urban reclaimed water using hydrophilic-lipophilic balance sorbent-embedded cellulose acetate membrane.

Urban reclaimed water is important water resource in China, while the residual new pollutants in the water largely challenge their safety for further use. China's action program for the management of new pollutants (also known as emerging contaminants) requires effective method for monitoring diverse new pollutants in water. This work proposed a highly sensitive passive sampling method for monitoring diverse new pollutants in urban reclaimed water. Hydrophilic-lipophilic balance sorbent-embedded cellulose acetate membranes (HECAMs) were dynamically deployed in self-developed continuous flow integrative sampling device (CFISD) for sampling four types of new pollutants with wide polarity ranges (1.11 < log Kow < 9.49) in a reclaimed water network for landscape irrigation in Beijing, China. The estimated equilibrium partition ratios of most chemicals between HECAM and water were over 104, which would provide low detection limits. In the 7-d high-efficiency deployment, thirty new pollutants were detected, which indicated incompletely removal of various new pollutants in wastewater treatment process. The dynamical accumulation data were successfully fitted by first-order kinetic model and different contaminants reached different accumulation phases in the HECAMs during 7 d. Acceptable and steady uptake rate constants and sampling rates were obtained with the use of CFISD in field sampling. The estimated time-weighted average concentrations for contaminants had wide concentration range and were from 0.03 ng L-1 (pendimethalin) to 3,394 ng L-1 (dibutyl phthalate) and this may lead to environmental risk for further use the reclaimed water. Dynamical deployment results also provided sensitive information of concentration fluctuations and twelve pollutants showed concentration fluctuations during the sampling period. In summary, HECAM showed high sensitivities and credible performance of monitoring diverse new pollutants in the urban reclaimed water.

Mitf, with Yki and STRIPAK-PP2A, is a key determinant of form and fate in the progenitor epithelium of the Drosophila eye.

The Microphthalmia-associated Transcription Factor (MITF) governs numerous cellular and developmental processes. In mice, it promotes specification and differentiation of the retinal pigmented epithelium (RPE), and in humans, some mutations in MITF induce congenital eye malformations. Herein, we explore the function and regulation of Mitf in Drosophila eye development and uncover two roles. We find that knockdown of Mitf results in retinal displacement (RDis), a phenotype associated with abnormal eye formation. Mitf functions in the peripodial epithelium (PE), a retinal support tissue akin to the RPE, to suppress RDis, via the Hippo pathway effector Yorkie (Yki). Yki physically interacts with Mitf and can modify its transcriptional activity in vitro. Severe loss of Mitf, instead, results in the de-repression of retinogenesis in the PE, precluding its development. This activity of Mitf requires the protein phosphatase 2 A holoenzyme STRIPAK-PP2A, but not Yki; Mitf transcriptional activity is potentiated by STRIPAK-PP2A in vitro and in vivo. Knockdown of STRIPAK-PP2A results in cytoplasmic retention of Mitf in vivo and in its decreased stability in vitro, highlighting two potential mechanisms for the control of Mitf function by STRIPAK-PP2A. Thus, Mitf functions in a context-dependent manner as a key determinant of form and fate in the Drosophila eye progenitor epithelium.

Smartphone-assisted array discrimination of sulfur-containing compounds and colorimetric-fluorescence dual-mode sensor for detection of 1,4-benzenedithiol based on peroxidase-like nanozyme g-C3N4@Cu, N-CDs.

Present work reported a novel nanozyme g-C3N4@Cu, N-CDs with excellent peroxidase-like activity obtained by loading Cu and N co-doped carbon dots on g-C3N4 (graphitic carbon nitride). g-C3N4@Cu, N-CDs can catalyze H2O2 to generate hydroxyl radical •OH, which oxidizes o-phenylenediamine to 2,3-diaminophenazine, which emits orange fluorescence under ultraviolet light irradiation. The experimental results confirmed that 1,4-benzenedithiol (BDT) could inhibit the peroxidase-like activity of g-C3N4@Cu, N-CDs. Based the principle above, a colorimetric-fluorescence dual-mode sensor for rapidly sensing of BDT was creatively constructed with assisting of a smartphone. The sensor showed excellent linearity over ranges of 0.75-132 µM and 0.33-60.0 µM with detection limits of 0.32 µM and 0.25 µM for colorimetric and fluorescence detection, respectively. Moreover, a smartphone-assisted colorimetric array sensor was constructed to distinguish six sulfur-containing compounds according to the difference in the degree of inhibition of nanozyme activity by different sulfur-containing compounds. The array sensor could distinguish sulfur-containing compounds at low concentration as low as 0.4 µM. The results validated that the designed sensor was a convenient and fast platform, which could be utilized as a reliably portable tool for the efficient and accurate detection of BDT and the discrimination of multiple sulfur compounds in real water samples.

Construction of fluorescent sensor array with nitrogen-doped carbon dots for sensing Sudan Orange G and identification of various azo compounds.

In this study, nitrogen-doped carbon dots (N-CDs) were facilely fabricated by one-pot hydrothermal method with levulinic acid and triethanolamine. A fluorescent sensor array was established for identifying azo compounds including Sudan Orange G (SOG), p-diaminoazobenzene, p-aminoazobenzene, azobenzene and quantitative detection of SOG. Experimental results revealed that azo compounds could quench the fluorescent intensity of N-CDs. Owing to various azo compounds showing different affinities to N-CDs, the sensor array exhibited different fluorescence quenching changes, which were further analyzed with principal component analysis to discriminate azo compounds. The sensor array was able to differentiate and recognize diverse concentrations of azo compounds from 0.25 to 2 mg/L. Simultaneously, a variety of factors affecting the detection of SOG were optimized. Under the optimized conditions, the sensor showed excellent stability and sensitivity. The sensor possessed marvelous linearity in the range of 0.1-1 mg/L and 1-4 mg/L and the detection limit was 27.82 µg/L. Spiked recoveries of 90.8-98.2 % were attained at spiked levels of 0.2 mg/L and 1 mg/L, demonstrating that the constructed fluorescence sensor was dependable and feasible for sensing SOG in environmental water samples.

High enrichment and measurement of heterocyclic aromatic hydrocarbons from environmental waters with magnetic resorcinol-formaldehyde nanocomposites coupled with high performance liquid chromatography.

Heterocyclic aromatic hydrocarbons are concerned pollutants with carcinogenic toxicity, which exist universally in various environmental matrices and have great harm to environmental and human health. In present work, magnetic resorcinol-formaldehyde composites (Fe3O4@SiO2@R-F) were fabricated via aldol condensation reaction under alkaline condition. The prepared magnetic materials were examined and analyzed with Fourier transform infrared spectroscopy and other related instruments. The Fe3O4@SiO2@R-F composites were utilized to develop an efficient magnetic solid phase extraction (MSPE) method for extracting six heteropolyclic aromatic hydrocarbons from environmental water samples including carbazole (CB), 7-methylquinoline (7-MQL), 9-methylcarbazole (9-MCB), dibenzothiophene (DBT), 4-methyldibenzothiophene (4-MDBT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT). The analytes were analyzed by high performance liquid chromatography-ultraviolet variable wavelength detector (HPLC-VWD). The main factors affecting MSPE were optimized. With the optimal parameters, 9-MCB and 4-MDBT have good linearity over the concentration range of 0.1-300 µg L-1, and 7-MQL, CB, DBT and 4,6-DMDBT have good linearity over the concentration range of 0.5-300 µg L-1. The limits of detection were over the concentration range of 0.012-0.031 µg L-1. This method was successfully employed to measure real waters, and the spiked recoveries ranged from 89.4% to 99.9%. The results confirmed that the developed method was reliable, robust and could be employed as a usefully alternate way for analyzing such pollutants in waters.

High enrichment and sensitive measurement of oxytetracycline in tea drinks by thermosensitive magnetic molecular imprinting based magnetic solid phase extraction coupled with boron doped carbon dots.

As a typical kind of new pollutants, there are still some challenges in the rapid detection of antibiotics. In this work, a sensitive fluorescent probe based on boron-doped carbon dots (B-CDs) in combination with thermo-responsive magnetic molecularly imprinted polymers (T-MMIPs) was constructed for the detection of oxytetracycline (OTC) in tea drinks. T-MMIPs were designed, fabricated and employed to enrich OTC at trace level from tea drinks, and B-CDs were utilized as the fluorescent probe to detect the concentration of OTC. The proposed method exhibited good linear relationship with OTC concentration from 0.2 to 60 µg L-1 and the limit of detection was 0.1 µg L-1. The established method has been successfully validated with tea beverages. Present work was the first attempt application of T-MMIPs in combination with CDs in detection of OTC, and demonstrated that the proposed method endowed the detection of OTC with high selectivity, sensitivity, reliability and wide application prospect, meanwhile offered a new strategy for the method establishment of rapid and sensitive detection of trace antibiotics in food and other matrices.

Strategy for establishing sensitive fluorescent sensor toward p-nitrophenol integrating magnetic molecularly imprinted materials and carbon dots.

In this work, a sensitive fluorescent sensor toward p-nitrophenol (4-NP) integrating magnetic molecularly imprinted materials and carbon dots (CDs) was proposed. Magnetic material and CDs derived from K3 [Fe(CN)6] and glucose were simultaneously obtained through simple one-step hydrothermal process. Introducing of molecularly imprinted materials based magnetic solid phase extraction (MSPE) endowed the constructed fluorescent sensor with higher sensitivity and selectivity. The significant factors affecting the sensitivity of the sensor toward 4-NP were optimized. Good linearity was obtained between fluorescent intensity of CDs and different concentration of 4-NP from 0.08 to 62.5 µg L-1. The sensitivity of constructed sensor was very low with detection limit of 0.02 µg L-1. Reliable applicability was also proved by the well-pleasing recoveries of 94.2-97.8% with different spiked concentrations of 4-NP in real environmental waters.

Quantitation of Atmospheric Suspended Polystyrene Nanoplastics by Active Sampling Prior to Pyrolysis-Gas Chromatography-Mass Spectrometry.

Plastic has been demonstrated to release nanoplastics (NPs) into the atmosphere under sunlight irradiation, posing a continuous health risk to the respiratory system. However, due to lack of reliable quantification methods, the occurrence and distribution of NPs in the atmosphere remain unclear. Polystyrene (PS) micro- and nanoplastics (MNPs) represent a crucial component of atmospheric MNPs. In this study, we proposed a simple and robust method for determining the concentration of atmospheric PS NPs using pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS). Following active sampling, the filter membrane is directly ground and introduced into the Py-GC/MS system to quantify PS NPs. The proposed method demonstrates excellent reproducibility and high sensitivity, with a detection limit as low as down to 15 pg/m3 for PS NPs. By using this method, the occurrence of PS NPs in both indoor and outdoor atmospheres has been confirmed. Furthermore, the results showed that the abundance of outdoor PS NPs was significantly higher than that of indoor samples, and there was no significant difference in NP vertical distribution within a height of 28.6 m. This method can be applied for the routine monitoring of atmospheric PS NPs and for evaluating their risk to human health.

Highly selective and sensitive determination of doxycycline integrating enrichment with thermosensitive magnetic molecular imprinting nanomaterial and carbon dots based fluorescence probe.

Doxycycline (DOX), a typical tetracycline antibiotic, is widely used because of its excellent antibacterial activity. To develop effective method for DOX has attracted much more attention. Herein, a new detection technology integrating magnetic solid phase extraction (MSPE) based on thermosensitive magnetic molecularly imprinted polymers (T-MMIPs) and fluorescence spectrometry based on carbon dots (CDs) was established. Thermosensitive magnetic molecularly imprinted polymers (T-MMIPs) was designed for selective enrichment of trace DOX. The synthesized T-MMIPs showed excellent selectivity for DOX. The adsorption performance of T-MMIPs varied with temperature in different solvents, which could achieve the enrichment and rapid desorption of DOX. In addition, the synthesized CDs had stable fluorescent property and better water-solubility, and the fluorescence of CDs was significantly quenched by DOX due to the internal filtration effect (IFE). Under the optimized conditions, the method resulted in good linearity over the range from 0.5 to 30 µg L-1, and the limit of detection was 0.2 µg L-1. The constructed detection technology was validated with real water samples, and excellent spiked recoveries from 92.5 % to 105.2 % were achieved. These data clearly indicated that the proposed technology was rapid, highly selective, environmentally friendly, and possessed significant potential application and development prospects.

ß-Cyclodextrin functionalized magnetic polyamine-amine dendrimers for high enrichment and effective analysis of trace bisphenolic pollutants in beverages.

Bisphenols (BPs) are typical endocrine disruptors, which can cause great effects on environmental, organisms and human health. In this study, ß-Cyclodextrin (ß-CD) functionalized polyamidoamine dendrimers-modified Fe3O4 nanomaterials (MNPs@PAMAM (G3.0)@ß-CD) were facilely synthesized. It exhibited good adsorption capacities for BPs, which was utilized to construct a sensitive tool in combination with high performance liquid chromatography for monitoring BPs such as bisphenol A (BPA), tetrabromobisphenol A (TBBPA), bisphenol S (BPS), bisphenol AF (BPAF) and bisphenol AP (BPAP) in beverage samples. The factors affecting the enrichment were examined such as generation of adsorbent, dosage of adsorbent, type and volume of eluting solvent, elution time and pH value of sample solution. The optimal parameters for enrichment was as follows: dosage of adsorbent, 60 mg; adsorption time, 50min; sample pH, pH7; elutent, 9 mL mixture of methanol and acetone(1:1); elution time, 6min; sample volume, 60 mL. The experimental results demonstrated that the adsorption conformed to pseudo-second-order kinetic model and Langmuir adsorption isotherm model. The results showed the maximum adsorption capacities of BPS, TBBPA, BPA, BPAF and BPAP were 131.80 µgg-1, 139.84 µgg-1, 157.08 µgg-1, 142.11 µgg-1 and 134.23 µgg-1, respectively. Under optimal conditions, BPS had good linear relationship over range from of 0.5-300 µgL-1, and the linear ranges of BPA, TBBPA, BPAF and BPAP ranged from 0.1 to 300 µgL-1. The limits of detection (S/N = 3) for BPs were good in range of 0.016-0.039 µgL-1. The spiked recoveries of target bisphenols (BPs) in beverages were approving over range from 92.3% to 99.2%. The established method possessed merits of easy to operate, good sensitivity, rapidness as well as environmental friendliness, and which earned great application potential for the enrichment and detection of trace BPs in practical samples.

Selective fluorescent probe for sensitive determination of bisphenol A based on molecularly imprinted polymers decorated carbon dots derived from citric acid and ethylenediamine.

Bisphenol A (BPA) is an endocrine disrupting chemical and poses a grave threat to the human health. Herein, a fluorescent probe constructed with molecularly imprinted polymers decorated carbon dots (CDs@MIPs) was proposed for determination of BPA with high selectivity. The CDs@MIPs were constructed using BPA, 4-vinylpyridine and ethylene glycol dimethacrylate as template, functional monomer and cross linker, respectively. The obtained fluorescent probe not only owned a highly selective recognition function derived from MIPs but also displayed an excellent sensitivity for sensing BPA stemmed from CDs. The fluorescence intensity of CDs@MIPs was varied before and after the removal of BPA templates. The fluorescent decrease fraction of the fluorescent probe demonstrates a nice linearity in BPA concentration range of 10-2000 nM (r2 = 0.9998) and the detection limit is as low as 1.5 nM. The fluorescent probe was triumphantly utilized to sense the level of BPA in real aqueous and plastic samples with good results. Moreover, the fluorescent probe offered a wonderful means for fast identification and sensitive detection of BPA from environmental aqueous samples.

Peripodial adherens junctions regulate Ajuba-Yorkie signaling to preserve fly eye morphology.

The Drosophila eye develops from the larval eye disc, a flattened vesicle comprised of continuous retinal and peripodial epithelia (PE). The PE is an epithelium that plays a supporting role in retinal neurogenesis, but gives rise to cuticle in the adult. We report here that the PE is also necessary to preserve the morphology of the retinal epithelium. Depletion of the adherens junction (AJ) components ß-Catenin (ß-Cat), DE-Cadherin or α-Catenin from the PE leads to altered disc morphology, characterized by retinal displacement (RDis); so too does loss of the Ajuba protein Jub, an AJ-associated regulator of the transcriptional coactivator Yorkie (Yki). Restoring AJs or overexpressing Yki in ß-Cat deficient PE results in suppression of RDis. Additional suppressors of AJ-dependent RDis include knockdown of Rho kinase (Rok) and Dystrophin (Dys). Furthermore, knockdown of ßPS integrin (Mys) from the PE results in RDis, while overexpression of Mys can suppress RDis induced by the loss of ß-Cat. We thus propose that AJ-Jub-Yki signaling in PE cells regulates PE cell contractile properties and/or attachment to the extracellular matrix to promote normal eye disc morphology.

Passive sampling of diverse pesticides in water by hydrophilic-lipophilic balance sorbent-embedded cellulose acetate membrane: Kinetics, equilibrium partitioning and field application.

Pesticides are useful products for agriculture and human life, but they are often released into surface waters and are hazardous to aquatic ecosystems. Pesticides monitoring in surface waters is challenging due to the great variety, ultratrace levels and nonpoint source pollution of pesticides; however, continuous passive sampling may be conducive to solving these problems. This work evaluated the performance of a newly developed passive sampler (hydrophilic-lipophilic balance sorbent-embedded cellulose acetate membrane, HECAM) for six types of currently used/present pesticides. The uptake kinetics and equilibrium partitioning of nineteen pesticides in different dissolved concentrations were studied by dynamic accumulation and equilibrium partitioning experiments, respectively. In the dynamic accumulation experiments, pesticides gradually accumulated in the HECAM and followed a first-order kinetic model. The same type of pesticides had roughly comparable accumulation concentrations. The estimated uptake rate constants ranged from 1.04 to 13.5 L g-1 d-1, and sampling rates ranged from 0.02 to 0.31 L d-1 for the pesticides in the HECAM (size of 2 cm × 3 cm). Pesticide accumulation concentrations in the HECAM increased linearly with increasing dissolved concentrations, which means that varying concentrations can also be monitored by the HECAM. In the equilibrium partitioning experiments, the pesticide partitioning behavior at varying dissolved concentrations can be described by the Freundlich model. The calculated equilibrium partition coefficients (log KD) for pesticides ranged from 3.32 to 4.54, and different pesticide types showed different changes with log Kow. Comparable results were found when estimating chemical equilibrium partition coefficients by the dynamic accumulation and equilibrium partitioning methods. Field deployment of the HECAM in river waters resulted in the detection of four pesticides, and the measured results were comparable to those of active sampling coupled with liquid-liquid extraction. These results suggest that the HECAM would be a promising strategy for simultaneously monitoring diverse pesticides in waters.