Dynamics changes of coastal aquaculture ponds based on the Google Earth Engine in Jiangsu Province, China.

Monitoring the spatiotemporal variation in coastal aquaculture zones is essential to providing a scientific basis for formulating scientifically reasonable land management policies. This study uses the Google Earth Engine (GEE) remote sensing cloud platform to extract aquaculture information based on Landsat series and Sentinel-2 images for the six years of 1984 to 2021 (1984, 1990, 2000, 2010, 2016 and 2021), so as to analyze the changes in the coastal aquaculture pond area, along with its spatiotemporal characteristics, of Jiangsu Province. The overall area of coastal aquaculture ponds in Jiangsu shows an increasing trend in the early period and a decreasing trend in the later period. Over the past 37 years, the area of coastal aquaculture ponds has increased by a total of 54,639.73 ha. This study can provide basic data for the sustainable development of coastal aquaculture in Jiangsu, and a reference for related studies in other regions.

Meteorological impacts on the unexpected ozone pollution in coastal cities of China during the unprecedented hot summer of 2022.

Surface ozone pollution under climate warming has become a serious environmental issue. In the summer of 2022, abnormal warming spread over most of the Northern Hemisphere and resulted in the abnormal increase in O3 concentrations. In this study, we focused on the coastal cities in China and investigated the O3 trends in July during 2015 to 2022. Four regions with different locations and emission levels were selected for comparison. A significant increase of O3 concentration in July 2022 were observed in the southern coastal cities (16.7-22.8 µg m-3) while the opposite characteristics were found in the northern coastal cities (decrease of 0.26-2.18 µg m-3). The results indicated various distribution patterns of the O3 concentrations responded to heat wave across China. The weakening of East Asian summer monsoon, extension of the western Pacific subtropical high, significant warming, stronger solar radiation, lower relative humidity, less rainfall and sinking motion of atmosphere in 2022 were beneficial for O3 generation and accumulation in the southern coastal areas. Meteorological changes in July 2022 could lead to an increase of 15.6 % in O3 concentrations in southern coastal cities compared to that in 2015-2021, based on the analysis of machine learning. Air temperature was the main contributor to high O3 concentrations in the coast of Fujian province, while other coastal cities depended on relative humidity. This study indicated the challenge of O3 pollution control in coastal areas under global warming, especially in extreme heat wave events.

Photochemistry in the urban agglomeration along the coastline of southeastern China: Pollution mechanism and control implication.

The concentrations of ground-level ozone (O3) in China have undergone a rapid increase in recent years, resulting in adverse impacts on the air quality and climate change. However, limited research has been conducted on the coastal urban agglomerations with increasingly serious O3 pollution. Therefore, in order to better understand in situ photochemistry, comprehensive field observations of O3 and its precursors, coupled with the model simulation, were conducted in autumn of 2019 at six sites in an urban agglomeration along the coastline of southeastern China. Results indicated that O3 pollution in the southern part of the urban agglomeration was more severe than that in the northern part, due to higher levels of O3 precursors and stronger atmospheric oxidation capacity (AOC) in the southern regions. Oxygenated volatile organic compounds (OVOCs), NO2, and CO dominated the total OH reactivity, and the site-average daytime Ox (O3 + NO2) increments correlated well (R2 = 0.94) with the total OH reactivity of CO and VOCs at these sites except for Quanzhou, where industrial emissions (35.1 %) and solvent usages (33.7 %) dominated the VOC sources. However, vehicle exhausts (31.1 %) were the most predominant contributors to the VOC sources at other sites. The results of model simulations showed that net O3 formation rates were larger at the southern sites. Furthermore, O3 production was mainly controlled by VOCs at most sites, but co-limited by VOCs and NOx at Quanzhou. The most significant VOC groups contributing to O3 formation were aromatics and alkenes, with m/p-xylene, toluene, propene, and ethene being the main contributors at these sites. This study offers a more comprehensive understanding of the characteristics and formation of photochemical pollutions on the scale of the urban areas, indicating the critical need to reduce VOC emissions as a means of mitigating their photochemical effects.

Source apportionment of PM2.5 and sulfate formation during the COVID-19 lockdown in a coastal city of southeast China.

Revealing the changes in chemical compositions and sources of PM2.5 is important for understanding aerosol chemistry and emission control strategies. High time-resolved characterization of water-soluble inorganic ions, elements, organic carbon (OC), and elemental carbon (EC) in PM2.5 was conducted in a coastal city of southeast China during the COVID-19 pandemic. The results showed that the average concentration of PM2.5 during the city lockdown (CLD) decreased from 46.2 µg m-3 to 24.4 µg m-3, lower than the same period in 2019 (PM2.5: 37.1 µg m-3). Concentrations of other air pollutants, such as SO2, NO2, PM10, OC, EC, and BC, were also decreased by 27.3%-67.8% during the CLD, whereas O3 increased by 28.1%. Although SO2 decreased from 4.94 µg m-3to 1.59 µg m-3 during the CLD, the concentration of SO42- (6.63 µg m-3) was comparable to that (5.47 µg m-3) during the non-lockdown period, which were attributed to the increase (16.0%) of sulfate oxidation rate (SOR). Ox (O3+NO2) was positively correlated with SO42-, suggesting the impacts of photochemical oxidation. A good correlation (R2 = 0.557) of SO42- and Fe and Mn was found, indicating the transition-metal ion catalyzed oxidation. Based on positive matrix factorization (PMF) analysis, the contribution of secondary formation to PM2.5 increased during the epidemic period, consisting with the increase of secondary organic carbon (SOC), while other primary sources including traffic, dust, and industry significantly decreased by 9%, 8.5%, and 8%, respectively. This study highlighted the comprehensive and nonlinear response of chemical compositions and formation mechanisms of PM2.5 to anthropogenic emissions control under relatively clean conditions.

Air pollution increases human health risks of PM2.5-bound PAHs and nitro-PAHs in the Yangtze River Delta, China.

Identifying the nature and extent of atmospheric PM2.5-bound toxic organic pollutants is beneficial to evaluate human health risks of air pollution. Seasonal observations of PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs (NPAHs) in the Yangtze River Delta (YRD) were investigated, along with criteria air pollutants and meteorological parameters. With the elevated PM2.5 level, the percentage of 4-ring PAHs and typical NPAH including 3-Nitrobiphenyl (3-NBP) and 2-Nitrofluoranthene (2-NFLT) increased by 19-40%. PM2.5-bound 2-NFLT was positively correlated with O3 and NO2, suggesting the contribution of atmospheric oxidation capacity to enhance the secondary formation of NPAHs in the atmosphere. Positive matrix factorization (PMF) analysis indicated that traffic emissions (44.9-48.7%), coal and biomass combustion (27.6-36.0%) and natural gas and volatilization (15.3-27.5%) were major sources of PAHs, and secondary formation (39.8-53.8%) was a predominant contributor to total NPAH concentrations. Backward trajectory analysis showed that air masses from North China transported to the YRD region increased PAH and NPAH concentrations. Compare to clean days, the BaP equivalent concentrations of total PAHs and NPAHs during haze pollution days were enhanced by 10-25 and 2-6 times, respectively. The Incremental Lifetime Cancer Risks (ILCRs) of PAHs by inhalation exposure also indicated high potential health risks in the YRD region. The results implied that the health risks of PM2.5-bound PAHs and NPAHs could be sharply enhanced with the increase of PM2.5 concentrations.

SERS and fluorescence detection of circulating tumor cells (CTCs) with specific capture-release mode based on multifunctional gold nanomaterials and dual-selective recognition.

Herein, a dual-selective recognition and multi-enhanced surface-enhanced Raman scattering (SERS)-fluorescence dual mode detection platform is designed for the detection of circulating tumor cells (CTCs). The gold nanoflowers (AuNFs) substrate was synthesized and the CTCs were captured on the surface area of AuNFs/ITO substrate by aptamers modified. At the same time, the novel nanoprobe was designed, anti-EpCAM (AE) and trigger DNA were modified onto the surface of gold nanostars (AuNSs) through a PEG linker. The novel nanoprobe identified CTCs through the specific recognition reaction between AE and the cell epithelial adhesion molecule of the CTCs. The dual-recognition cellular mechanism of the aptamers and AE improves selectivity. Then, the complementary sequence (CS) hybridize with aptamers to release the captured CTCs into the culture medium. The number of CTCs released was detected by SERS and fluorescence. The limit of SERS detection was 5 cells/mL with a linear relationship from 5 to 200 cells/mL. The limit of fluorescence detection was 10 cells/mL with a linear relationship from 10 to 200 cells/mL. Thus, the developed CTCs detection platform demonstrates promising applications for clinical diagnosis.

A Green-Emission Metal-Organic Framework-Based Nanoprobe for Imaging Dual Tumor Biomarkers in Living Cells.

The modular nature of metal-organic frameworks (MOFs) permits their tunable structure and function for target application, such as in biomedicine. Herein, a green-emission Zr(IV)-MOF (BUT-88) was constructed from a customized luminescent carbazolyl ligand. BUT-88 represents the first bcu-type MOF with both organic linker and metal node in eight connections and shows medium-sized pores, rich accessible linking sites, and good water stability and biocompatibility. In virtue of these merits, BUT-88 was then fabricated into a MOF-based fluorescent nanoprobe, drDNA-BUT-88. Using it, the live-cell imaging of dual tumor biomarkers was achieved for the first time upon a MOF-based probe, offering enhanced detection precision in early cancer diagnosis. Particularly, the probe showed efficient ratiometric fluorescent sensing toward the cytoplasmic biomarker microRNA-21, further improving the detection accuracy at the cellular level. In this work, the elaborate combination of MOF engineering and the fluorescent detection technique has contributed a facile biosensing platform, unlocking more possibilities of MOF chemistry.

Non-template synthesis of porous carbon nanospheres coated with a DNA-cross-linked hydrogel for the simultaneous imaging of dual biomarkers in living cells.

We designed a dual-color fluorescent nanoprobe for simultaneous detection and imaging of adenosine triphosphate and glutathione in living cells based on porous carbon nanospheres and a DNA hybrid hydrogel. Due to the non-template synthesis process and good biocompatibility, the nanohydrogel displayed a short preparation time and anti-nonspecific adsorption.

DNAzyme-functionalized porous carbon nanospheres serve as a fluorescent nanoprobe for imaging detection of microRNA-21 and zinc ion in living cells.

The present study shows that a dual-signal nanoprobe consisting of DNAzyme-functionalized porous carbon nanospheres (PCNs) responds to microRNA-21 and zinc ion (Zn2+). The fluorescent probe undergoes an increase in the fluorescence intensity of fluorescein isothiocyanate (FITC) (with excitation/emission wavelengths at 488/517 nm) and the fluorescence intensity of cyanine-5 (Cy5) (with excitation/emission wavelengths at 633/670 nm) in the presence of microRNA-21 and Zn2+. The recognition between microRNA-21 and its complementary strand in the PCNs induces the separation of Zn2+-specific DNAzyme from PCNs, thus resulting in the increase of green fluorescence, and the exogenous Zn2+ triggers the rupture of cleavage strand of DNAzyme and recovery of red fluorescence. This nanoprobe allows us to acquire in vitro the determination of microRNA-21 in the range of 2-300 nM with a detection limit of 0.57 nM and the determination of Zn2+ in the range 2-100 nM with a detection limit of 0.43 nM, and in situ simultaneous imaging in MCF-7 breast cancer cells. Therefore, this strategy permits to obtain the expression levels of different biomarkers in living cells, providing a useful tool for diagnosis of cancers and understanding their biological process. Graphical abstract Schematic representation of the DNAzyme-functionalized porous carbon nanospheres for the imaging analysis of microRNA-21 and Zn2+ in living cells.

Green-emitting carbon dot loaded silica nanoparticles coated with DNA-cross-linked hydrogels for sensitive carcinoembryonic antigen detection and effective targeted cancer therapy.

Herein, we have designed bifunctional composite nanospheres for carcinoembryonic antigen (CEA) sensing and targeted drug delivery, based on carbon dot loaded silica nanoparticles coated with DNA-cross-linked hydrogels. As a result, highly sensitive and selective CEA detection was achieved in vitro, and an effective cytotoxic effect was realized in vivo after loading doxorubicin.

Size-controlled DNA-cross-linked hydrogel coated silica nanoparticles served as a ratiometric fluorescent probe for the detection of adenosine triphosphate in living cells.

Herein, we have designed a ratiometric fluorescent nanoprobe for adenosine triphosphate sensing and imaging in living cells, based on silica nanoparticles and a DNA-functionalized hybrid hydrogel. This ratiometric detecting method could validly avoid false-positive signals. Due to its controllable size, favorable biocompatibility and biostability, the nanohydrogel exhibited high cellular permeability and fast response in living cells.

Locked Nucleic Acid Nanomicelle with Cell-Penetrating Peptides for Glutathione-Triggered Drug Release and Cell Fluorescence Imaging.

Herein, we constructed a multifunctional spherical nanomicelle drug delivery system to improve the efficiency of cell uptake. The paclitaxel (PTX)-locked nucleic acid (LNA) monomer and the carboxyfluorescein (FAM)-labeled DNA were mixed together to assemble and form a spherical nanomicelle that was functionalized with transactivator of transcription (TAT), a cell-penetrating peptides (CPPs). A bioreductively activated disulfide was used to link the hydrophobic PTX to the LNA, allowing the PTX to be released freely in the presence of glutathione (GSH) upon cell uptake. Based on magnetic separation, the synthetic process of PTX-LNA monomers avoids time-consuming and labor-intensive shortcomings. Cellular uptake of PTX-LNA-TAT nanomicelle and the drug release occur rapidly as proved by fluorescence microscopy and flow cytometry. The resulting nanomicelle was greater stability, monodisperse size, and the high therapeutic potential. Furthermore, the system can readily achieve detection of GSH in the cancer cells. The detection limit for commercial GSH determined was 1.0 × 10-9 M by using PTX/Fluorescein isothiocyanate (FITC)-LNA/black hole quencher 1 (BHQ-1) as a probe.

A DNA Nanotube-Peptide Biocomplex for mRNA Detection and Its Application in Cancer Diagnosis and Targeted Therapy.

A biocomplex of DNA nanotube-peptide, consisting of six concatenated DNA strands, three locked DNA strands, and a cell-penetrating peptide, is reported. The barrel-structured DNA nanotube-peptide was successfully applied as a codrug-delivery system for targeting cancer therapy. The mucin 1 protein (MUC-1) aptamer is part of a DNA nanotube that can specifically recognize MUC-1 protein on the surface of MCF-7 cells. Cyclo (Arg-Gly-Asp-d-Phe-Lys; cRGD), as a cell-penetrating peptide, facilitates recruitment and uptake of targeting drugs by binding to integrin receptors (αv ß3 ) of the cytomembrane surface. Anticancer drugs doxorubicin (DOX) and paclitaxel (PTX) were loaded into the capsulated DNA nanotube-peptide (CDNP), which was used as codrug cargo models. The as-prepared biocomplex can be utilized not only to deliver drugs, but also to achieve anticancer effects in vivo. Experimental results suggested that the treatment efficacy of the codrug delivery platform (CDNP/DOX/PTX) was better than that of a single-drug delivery platform (CDNP/DOX or CDNP/PTX). This system, which is composed of DNA strands and peptide, has good biocompatibility and biodegradability. Furthermore, the system can readily detect target mRNA in MCF-7 cells in vitro. The detection limits of mRNA are 9.7×10-8 and 1.8×10-8 m with CDNP/DOX and CDNP/PTX-FITC (FITC=fluorescein isothiocyanate), respectively, as probes.

A novel fluorescent biosensor for Adenosine Triphosphate detection based on the polydopamine nanospheres integrating with enzymatic recycling amplification.

Based on the protective performance of polydopamine nanospheres (PDANSs) for DNA against nuclease digestion and the specific recognition characteristic of aptamer, we have developed an enzymatic recycling signal amplification method for highly sensitive and selective detection of adenosine triphosphate (ATP). Fluorescence measurements were carried out to verify the DNA polymerase and exonuclease III (Exo III) assisted target recycling process and fluorescence signal amplification. In the absence of the ATP, initially, the signal DNA-PDANSs complex was in the "off" state due to the efficient fluorescence quenching of 6-carboxyfluorescein (FAM) adjacent to the surface of PDANSs. Due to the binding of the aptamer by ATP, it trigger DNA polymerase and Exo III assisted target recycling process by the product of release, the complex would change into the "on" state as a result of the dissociation of the FAM from the surface of PDANSs, thus providing greatly enhanced fluorescence emission intensity. The method allows quantitative detection of ATP in the range of 20-600nM with a detection limit of 8.32nM. This biosensor requires no complex operations, and is a new high efficiency method for ATP detection.

Robust Satisficing Decision Making for Unmanned Aerial Vehicle Complex Missions under Severe Uncertainty.

This paper presents a robust satisficing decision-making method for Unmanned Aerial Vehicles (UAVs) executing complex missions in an uncertain environment. Motivated by the info-gap decision theory, we formulate this problem as a novel robust satisficing optimization problem, of which the objective is to maximize the robustness while satisfying some desired mission requirements. Specifically, a new info-gap based Markov Decision Process (IMDP) is constructed to abstract the uncertain UAV system and specify the complex mission requirements with the Linear Temporal Logic (LTL). A robust satisficing policy is obtained to maximize the robustness to the uncertain IMDP while ensuring a desired probability of satisfying the LTL specifications. To this end, we propose a two-stage robust satisficing solution strategy which consists of the construction of a product IMDP and the generation of a robust satisficing policy. In the first stage, a product IMDP is constructed by combining the IMDP with an automaton representing the LTL specifications. In the second, an algorithm based on robust dynamic programming is proposed to generate a robust satisficing policy, while an associated robustness evaluation algorithm is presented to evaluate the robustness. Finally, through Monte Carlo simulation, the effectiveness of our algorithms is demonstrated on an UAV search mission under severe uncertainty so that the resulting policy can maximize the robustness while reaching the desired performance level. Furthermore, by comparing the proposed method with other robust decision-making methods, it can be concluded that our policy can tolerate higher uncertainty so that the desired performance level can be guaranteed, which indicates that the proposed method is much more effective in real applications.

Enhanced chemiluminescence detection of glutathione based on isoluminol-PSM nanoparticles probe.

In this paper, a new chemiluminescence (CL) strategy was constructed for the determination of physiological thiols by using an isoluminol labeled nano-probe. The amino group on the surface of the magnetic beads (MBs) were converted into pyridyl disulfide groups by treatment with N-succinimidyl-3-(2-pyridyldithio)propionate (SPDP), in the meantime, isoluminol and thiolated signal DNA were labeled on the surface of the polystyrene microspheres (PSMs). By treating the SPDP activated MBs with the modified PSMs, isoluminol molecules on the surface of the PSMs, along with the thiolated signal DNA, were attached to the surface of the MBs through disulfide bonds to form a CL probe. In the presence of glutathione (GSH), the disulfide bonds could be cleaved readily. The isoluminol molecules modified on the surface of the PSMs released from the CL probes were detached by magnetic separation and transferred to the dark closet for CL detection of isoluminol-H2O2-HRP system. Using GSH detection as a model, we prove a linear dose response in the range from 5 × 10(-10) to 8 × 10(-8)M. The detection limit of this trial for GSH determined is 5 × 10(-10)M. The proposed design was successfully applied to the extracts of K562 cell for intracellular thiols detection, the average amount of thiols was about 4.114 × 10(-13)M per K562 cell.

Simultaneous electrochemical determination of two analytes based on nuclease-assisted target recycling amplification.

In the present study, a method for simultaneous determination of two different DNAs is developed based on nuclease-assisted target recycling and nanoparticle amplification. The target recycling process is accomplished by taking advantage of the cleavage property of nicking endonuclease (NEase) for specific nucleotide sequences in duplex. In the presence of target DNA, the linker DNA in our detection system can hybridize with the target and be cleaved to form short fragments. Thus the target DNA is released and recognized by another linker DNA, activating the next round of cleavage reaction. On the other hand, two bio-barcode probes, a PbS nanoparticles (NPs)-DNA probe and a CdS NPs-DNA probe, are used for tracing two target DNAs to further amplify the detection signals. Based on a sensitive differential pulse anodic stripping voltammetry (DPASV) method for the simultaneous detection of Pb(2+) and Cd(2+) obtained by dissolving two probes, two different target DNAs are determined with high sensitivity and single-base mismatch selectivity.

Design of a sensitive aptasensor based on magnetic microbeads-assisted strand displacement amplification and target recycling.

A cross-circular amplification system for sensitive detection of adenosine triphosphate (ATP) in cancer cells was developed based on aptamer-target interaction, magnetic microbeads (MBs)-assisted strand displacement amplification and target recycling. Here we described a new recognition probe possessing two parts, the ATP aptamer and the extension part. The recognition probe was firstly immobilized on the surface of MBs and hybridized with its complementary sequence to form a duplex. When combined with ATP, the probe changed its conformation, revealing the extension part in single-strand form, which further served as a toehold for subsequent target recycling. The released complementary sequence of the probe acted as the catalyst of the MB-assisted strand displacement reaction. Incorporated with target recycling, a large amount of biotin-tagged MB complexes were formed to stimulate the generation of chemiluminescence (CL) signal in the presence of luminol and H2O2 by incorporating with streptavidin-HRP, reaching a detection limit of ATP as low as 6.1×10(-10)M. Moreover, sample assays of ATP in Ramos Burkitt's lymphoma B cells were performed, which confirmed the reliability and practicality of the protocol.

Sensitive SERS detection of DNA and lysozyme based on polymerase assisted cross strand-displacement amplification.

A novel surface-enhanced Raman scattering (SERS) assay is demonstrated by developing a cross strand-displacement amplification (CSDA) method to enhance the SERS signals. Highly sensitive and selective detection of any single-stranded DNA is achieved and an aptasensor for proteins is constructed.

Chemiluminescence aptasensor for cocaine based on double-functionalized gold nanoprobes and functionalized magnetic microbeads.

A novel chemiluminescence (CL) aptasensor for highly sensitive detection of small-molecule targets using cocaine as a model analyte was developed in the present study. For the proposed aptasensor, the aptamers were immobilized on the surface of gold nanoparticles (AuNPs) functionalized magnetic microbeads (MB-AuNPs) and then hybridized with the signal DNA on the double-functional gold nanoprobes (DF-AuNPs) modified with horseradish peroxidase (HRP). When cocaine was introduced, a competition for the aptamer between cocaine and the signal DNA occurred and the gold nanoprobes were forced to dissociate from the MB-AuNPs surface based on the structure switching of the aptamer. The CL signals of Luminol-H(2)O(2)-HRP-PIP system were proportional to the concentration of cocaine. A linear range was obtained when the concentrations of cocaine were from 1 × 10(-9) to 1 × 10(-8) M with the detection limit of 0.48 nM (3σ), much lower than those achieved by other methods. This new system can be easily extended to a variety of small-molecules, protein, and tumor cell analysis.