On-site electrochemical determination of phosphate with high sensitivity and anti-interference ability in turbid coastal waters.

Phosphate is considered to be an important biogenic element and responsible for eutrophication in aquatic ecosystems, existing in both dissolved and absorbed forms. Due to the complex matrix of coastal seawater, a high sensitivity and anti-interference method for phosphate detection is required for environmental protection. In this study, a novel electrochemical method was proposed based on reduced graphene oxide-ordered mesoporous carbon screen-printed electrode (rGO-OMC/SPE) analysis, allowing sensitivity and reliable determination of phosphate in turbid coastal waters. Combining the good absorption capacity of OMC with the excellent electroconductivity of rGO, the fabricated electrode exhibits improved signal responses, enhanced by up to 43-fold. The platform was evaluated using turbidity interference test with good recovery percentages comprised between 96% and 105% in different phosphate concentration, and salinity interference test between 92% and 105%, respectively. A linear range from 0.2 to 150 µM phosphate was achieved, with a detection limit of 0.05 µM (s/n = 3). The fabricated platform was successfully used for on-site analysis of phosphate in turbid coastal waters. This reliable and effective method for the analysis of phosphate in turbid coastal waters allows for sensitivity and anti-interference determination, while also representing a significant step towards comprehensive and convenient analysis of phosphorus species.

Nanocomposite based on graphene and intercalated covalent organic frameworks with hydrosulphonyl groups for electrochemical determination of heavy metal ions.

An electrochemical sensor constructed by intercalated composites was developed for determination of heavy metal ions. The intercalated composites were composed of hydrosulphonyl functional covalent organic frameworks (COF-SH) and graphene (G). The presence of numerous adsorption sites, such as 18 sulfur atoms and 30 nitrogen atoms per big circle of COFs on COF-SH, was beneficial for the accumulation of heavy metals, while the graphene enhanced the electrical conductivity. The obtained sensor under the optimal conditions successfully detected the presence of heavy metal ions in coastal water samples at concentrations ranging from 1 to 1000 µg L-1. The detection limits of Cd (II), Pb (II), Cu (II), and Hg (II) were 0.3, 0.2, 0.2, and 1.1 µg L-1, respectively. Furthermore, the sensor still exhibited good stability after multiple uses less than 5%. When it is used in the analysis of actual samples, the recovery of standard addition is higher than 95%. In sum, the combination of hydrosulphonyl functional COFs with graphene looks very promising for the assembly of sensors with high sensitivity toward the determination of heavy metal ions for coastal environmental monitoring.

Study on anti-scaling of landfill leachate treated by evaporation method.

In the mechanical vapor recompression (MVR) treatment of landfill leachate, scaling in the evaporator and heat exchanger poses a serious problem. This study explored the reasons for such scaling and proposed acid or ion-exchange pre-treatments to reduce the alkalinity of the landfill leachate nanofiltration concentrate (LLNC) to prevent scaling. The feasibility of these two methods was evaluated and the technical and economic parameters for application were obtained via experiments. A large amount of HCO3- in the LLNC was the main cause of scaling. The acid addition experiment and field application demonstrated that this method could prevent fouling problems. The cost of acid addition was USD 0.18/t. LLNC pre-treatment by ion-exchange showed that a weakly acidic cation-exchange resin performed better than a strongly acidic cation-exchange resin did. The amount of solid residue under an alkalinity of 0 mg/L could be decreased by 92.9% compared with that of raw LLNC during evaporation. Both methods could alleviate scaling and enable the wide application of the MVR evaporation process in landfill leachate treatment.

Quantitative assessment on soil concentration of heavy metal-contaminated soil with various sample pretreatment techniques and detection methods.

Detection and quantification of heavy metals in soil samples are significant in terms of environmental monitoring and risk assessment for metals. In order to improve the accuracy and precision to detect heavy metal, in this study, four standard samples (NASS-4, NASS-5, NASS-9, and NASS-16) were analyzed by evolving heating (electric heating plate, water bath, and microwave) and acidic systems (includes HCl, HNO3, HF, and HClO4). The result shows that different pretreatment methods have different effects on the extraction of heavy metal elements and five heavy metal elements (Cu, Zn, Pb, Ni, and Cr) were selected for optimization through pretreatment methods. Although the contents of heavy metals were same but we found diversity in the results. Under optimal conditions, the selected standard samples were analyzed by inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and atomic absorption spectroscopy (AAS), and the results were compared. The results show that different elements have their own most suitable detection methods, such as for Pb, the most suitable method is ICP-MS; and for Zn, the most suitable method is AAS. Pretreatment methods and detection techniques are combined to find and improve accuracy of results for certain elements. This study provides a reliable detection method for the accurate detection of heavy metals in the environment.

A facile synthesis of perforated reduced graphene oxide for high performance electrochemical sensors.

Highly active perforated reduced graphene oxide (P-rGO) was synthesized by a facile methodology based on co-deposition of graphene oxide with sacrificial Prussian blue. Electrode surface properties were characterized by SEM and EDS. The GC/P-rGO electrode exhibited a larger specific surface area than that of GCE. These findings highlighted that the signal was enhanced for both dopamine detection and selenium detection by using P-rGO as a relevant supporting substrate. The result indicated that the large number of perforated structures formed numerous electrically conductive channels in the structure, improving the electrocatalytic properties.

"Doctors Killed My Baby": Argumentative Patterns in Medical Disputes in China.

The recent surge in medical disputes requires that more attention be paid to the voices of laypeople. This article explores the argumentative nature of the public discourse of the reported "malpractice mobs" that strive to convince members of the public (in the place of health or legal experts) that they have been victims of medical errors and injustice. This case-based qualitative empirical study uses a pragma-dialectical approach to suggest a prototypical pattern of such public appeals that contains a basic argumentative pattern and various types of extensions. The presence and influence of cultural factors are identified and discussed. The results of the analysis indicate that "malpractice mobs" largely display a tendency to target certain drugs, treatments or therapeutic methods based on folk interpretations of medical phenomena among individual ethnic groups, which may be regarded as cultural preferences in the medical domain. Although these preferences have little coercive power, in the absence of institutional restraints, they may have a powerful impact. The introduction of cultural preferences into pragmatic argumentation explains not only why some critical questions are emphasized (whereas others are invariably ignored) but also why certain types of support are repeatedly demanded in public appeals. The findings suggest the importance of paying greater attention to the argumentation of laypeople in medical disputes in China and the essential role of a culturally sensitive model of argumentation theory in improving health communication.

Voltammetric determination of copper in seawater at a glassy carbon disk electrode modified with Au@MnO2 core-shell microspheres.

Anodic stripping voltammetric determination of copper ions was accomplished at a glassy carbon disk electrode modified with core-shell microspheres of the gold@manganese dioxide (Au@MnO2) type. These were synthesized via electrochemical deposition. The gold nanoparticles (AuNPs) were electrochemically deposited and employed as an active support material for the growth of MnO2 to yield Au@MnO2 core-shell particles with unique and regular spherical morphology. The microspheres have a diameter of 200-250 nm and scrolled edges like a cactus. Due to the absorption capacity of MnO2 and the electrocatalytic ability of the AuNPs, an excellent anodic signal is obtained for copper ions. Response is linear in the 20 nM to 1 µM copper ion concentration range, with a 4.9 ± 0.2 nM (n = 3) detection limit under optimized conditions. The electrode is stable and excellently reproducible. It was successfully applied to the analysis of copper ions in spiked seawater samples. Graphical abstract Gold nanoparticles were employed as a coupling medium for the bridging of MnO2 on a glassy carbon disk electrode to transfer electrons that enhanced electrochemical detection of copper ions.

Vertical profile, contamination assessment of mercury and arsenic in sediment cores from typical intertidal zones of China.

The vertical profiles, contamination levels, and potential ecological risks of mercury and arsenic were studied from the sediment cores of seven typical intertidal zones, including the Liaohe River Estuary, the Jianhe River Estuary, the Dagu River Estuary, Yancheng Shoal, the Dongtan Yangtze River Estuary, Hangzhou Bay, and the Pearl River Estuary. Marine sediment quality standards, the threshold effect level (TEL), and the probable effect level (PEL) were used as guidelines to evaluate sediment quality. In addition, the geo-accumulation index (Igeo) and potential ecological risk index ([Formula: see text]) were used to assess contamination and potential ecological risks from mercury and arsenic. The results showed that the Pearl River Estuary was moderately polluted by mercury and represented a high potential ecological risk, while other areas were uncontaminated or mildly contaminated with low or moderate potential ecological risks. The Pearl River Estuary was mildly polluted by arsenic and represented a mild potential ecological risk, while other areas were unpolluted and also posed a mild potential ecological risk.

Simultaneous Speciation Analysis of Trace Heavy Metals (Cu, Pb, Cd and Zn) in Seawater from Sishili Bay, North Yellow Sea, China.

Different species of trace heavy metals (HMs) in seawater samples were simultaneously analyzed by anodic stripping voltammetric method, an analytical technique that does not require sample pre-concentration or the addition of reagents. The effects of the crucial parameters, deposition potential and time, on the determination of HMs were investigated. Concentrations of the total dissolved, dissolved active, and dissolved inert HMs were obtained through different analysis processes. The three species of Cu, Pb, Cd and Zn in seawater samples collected in different locations across Sishili Bay, North Yellow Sea, China were studied. The relative concentration of the dissolved active Cu, Pb, Cd and Zn in the total dissolved concentrations is 59.0%, 69.6%, 87.3% and 84.1%, respectively. The concentrations of different HMs species in Sishili Bay could be affected by the discharged effluent, sea current, and uptake of marine organism.

Fenton-like reaction-mediated etching of gold nanorods for visual detection of Co(2+).

We have proposed a Fenton-like reaction-mediated etching of gold nanorods and applied it to the sensitive visual detection of Co(2+) ions. With the presence of bicarbonate (HCO3(-)) and hydrogen peroxide(H2O2), Co(2+) ions trigger a Fenton-like reaction, resulting in the generation of superoxide radical (O2(•-)). As a result, the gold nanorods are gradually etched by O2(•-) in the presence of SCN(-), accompanied by an obvious color change from green to red. The gold nanorods etching process preferentially occurs along the longitudinal direction, which is observed by transmission electron microscope. The etching mechanism is carefully proved by investigating the effects of different radical scavengers (e.g., dimethyl sulfoxide). The auto-oxidation of hydroxylamine assay further confirms the mechanism. Then, the main factors, including reactants concentrations, temperature, and incubation time, are specifically investigated. Under optimized conditions, we get an excellent sensing performance for Co(2+) with a lower detection limit of 1.0 nM via a spectrophotometer and a visual detection limit of 40 nM. In addition, this principle may provide a new concept of "intermediate-mediated etching of nanoparticles" for sensing.

All-solid-state polymeric membrane ion-selective miniaturized electrodes based on a nanoporous gold film as solid contact.

A new type of all-solid-state polymeric membrane ion-selective electrodes (ISEs) is developed by using a nanoporous gold (NPG) film as solid contact. The NPG film is in situ formed on the surface of a gold wire electrode by the multicyclic electrochemical alloying/dealloying method. The characteristics of the NPG film, such as the large surface area, high double layer capacitance, and good conductivity, have been demonstrated by cyclic voltammetry and electrochemical impedance spectroscopy. The NPG film offers a well-defined interface between the electronic conductor and the ion-selective membrane. The NPG film-based all-solid-state K(+) ISE shows a stable Nernstian response within the concentration range from 10(-6) to 10(-2) M, and the detection limit is 4.0 × 10(-7) M. The proposed electrode exhibits an improved potential stability with a reduced water layer in comparison with the coated-wire K(+)-ISE, which is due to the bicontinuous electron- and ion-conducting properties of the ionophore-doped polymeric membrane/NPG film interlayer. Unlike the additionally coated intermediate layers as single-use solid contacts, the in situ formed NPG film as solid contact is reusable. This work provides a versatile method for fabricating the robust, reliable, and low-maintenance miniaturized ISEs.

Spatial distribution, compositional pattern, and source apportionment of colloidal trace metals in the coastal water of Shandong Peninsula, northeastern China.

The Shandong Peninsula (SP) is the largest peninsula in China hosting rich economic and agricultural activities. In this study, we investigated the behavior of dissolved Mn, Fe, Cu, Zn, Cd, and Pb and their colloidal phases in the coastal and estuarine areas of SP. Pb and Zn had the highest contamination factors of 0.22-10.15 and 0.90-4.41, respectively. The <1 kDa accounted for 23-57 % of the total dissolved phase. Mn, Fe, Cu, Zn, Cd, and Pb were more likely to bind to 100 kDa-0.45 µm colloids (21-57 %). For colloidal Fe and Cu, the adsorption-release behavior had more significant effects on their dynamics. In contrast, the changes in colloidal Mn, Cd, and Pb were mainly controlled by the combined influence of temperature, dissolved oxygen, and microbial activity. However, the 1-3 kDa Zn exhibited a greater pH-dependent dispersion and was significantly positively correlated with it.

The influences of Yellow River input and nutrient dynamics on colloidal Fe migration in the Bohai Sea, China.

The coupling relationship between the <1 kDa, 1-3 kDa, 3-10 kDa, 10-100 kDa, and 100 kDa-0.45 µm Fe fractions and the environmental factors in the Bohai Sea (BS) was investigated. The 1-100 kDa Fe in the surface water exhibited a non-conservative phenomenon during the river-sea mixing process, which was related to the removal of colloidal Fe via flocculation during this process. For the bottom water, the ligands released by the sediments may form additions to the <100 kDa Fe. The COC and DOC were mainly closely related to the behavior of the Fe in the bottom water. The <1 and 3-10 kDa Fe was mainly significantly positively correlated with the DOC, while the <100 kDa-0.45 µm Fe was significantly negatively correlated with the DOC. <100 kDa LMW colloidal Fe exhibited more synergistic behavior with easily absorbed ammonium salts.

New insights into estimation of bioavailable inorganic phosphorus in natural coastal seawater.

Considering the impact of the high salinity and high turbidity of coastal seawater on phosphorus forms, a new method was proposed to determine bioavailable inorganic phosphorus (BIP). The phosphorus most relevant to eutrophication is BIP, and traditional analysis methods may underestimate the degree of eutrophication. In this study, a microelectrode of multigold (AuµE) was fabricated for direct voltammetric determination of BIP without filtration, and BIP environmental characteristics including distribution and correlation relationships with environmental factors in typical coastal seawater of Northern China were analyzed. The proposed AuµE showed a low detection limit of 0.03 µM. The surface and bottom BIP concentrations ranged from 1.00 to 2.13 and from 0.88 to 2.05 µM, respectively. BIP dominated the total P (TP) accounting for 48.5-67.5 % in the surface layer samples, and 32.6-92.7 % in the bottom layer samples, respectively. The concentrations of BIP were obviously higher than those of DIP, indicating that DIP may underestimate the probability of eutrophication occurring. And BIP was positively correlated with dissolved oxygen (DO) (P < 0.05). BIP may be a promising indicator of eutrophication potential in coastal areas with high salinity and high turbidity. The proposed reliable voltammetry method provides a new indicator for environmental assessment and represents a significant step in the comprehensive analysis of P species.

Field determination and ecological health risk assessment of trace metals in typical mariculture area of China.

Field determination of dissolved trace metals (Cu, Pb and Cd) by using automated electrochemical system had been done in three typical mariculture areas of Yellow Sea (YS), East China Sea (ECS) and South China Sea (SCS) in China. Higher concentrations of Cu and Pb were found in ECS while the Cd concentration showed a decreasing trend from north to south of China. The metal distribution and ecological health risk assessments were also conducted. Cu and Pb in the YS and Cu in SCS were moderately contaminated. ECS had considerable Cu contamination and very high Pb contamination. Compared with other coastal areas, mariculture affected the concentration and spatial distribution of trace metals, but it was not a necessarily dominant factor. Overall, the results contribute to the further development of field and on-board metal detection technology and lay a foundation for the realization of field ecological health risk assessments of mariculture waters.

Prediction of multiple types of drug interactions based on multi-scale fusion and dual-view fusion.

Potential drug-drug interactions (DDI) can lead to adverse drug reactions (ADR), and DDI prediction can help pharmacy researchers detect harmful DDI early. However, existing DDI prediction methods fall short in fully capturing drug information. They typically employ a single-view input, focusing solely on drug features or drug networks. Moreover, they rely exclusively on the final model layer for predictions, overlooking the nuanced information present across various network layers. To address these limitations, we propose a multi-scale dual-view fusion (MSDF) method for DDI prediction. More specifically, MSDF first constructs two views, topological and feature views of drugs, as model inputs. Then a graph convolutional neural network is used to extract the feature representations from each view. On top of that, a multi-scale fusion module integrates information across different graph convolutional layers to create comprehensive drug embeddings. The embeddings from the two views are summed as the final representation for classification. Experiments on two real-world datasets demonstrate that MSDF achieves higher accuracy than state-of-the-art methods, as the dual-view, multi-scale approach better captures drug characteristics.

A thermo-responsive hydrogel for body temperature-induced spontaneous information decryption and self-encryption.

A thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) hydrogel, exhibiting an interesting phenomenon of an opaque-transparent-opaque transition in the successive processes of heating and cooling, is reported. It is fabricated by means of both the porogenic effect of hydroxypropyl cellulose and the cononsolvency effect of PNIPAM in a mixed solvent of dimethyl sulfoxide and water. After being mildly triggered by body temperature, the hydrogel is used to spontaneously decrypt the quick response code within 4 min and then autonomously encrypts the code again within 10 min at room temperature. The mechanism for the transient transparency of hydrogels during the quenching process has been elucidated.

Dissolving microneedle system containing Ag nanoparticle-decorated silk fibroin microspheres and antibiotics for synergistic therapy of bacterial biofilm infection.

Most cases of delayed wound healing are associated with bacterial biofilm infections due to high antibiotic resistance. To improve patient compliance and recovery rates, it is critical to develop minimally invasive and efficient methods to eliminate bacterial biofilms as an alternative to clinical debridement techniques. Herein, we develop a dissolving microneedle system containing Ag nanoparticles (AgNPs)-decorated silk fibroin microspheres (SFM-AgNPs) and antibiotics for synergistic treatment of bacterial biofilm infection. Silk fibroin microspheres (SFM) are controllably prepared in an incompatible system formed by a mixture of protein and carbohydrate solutions by using a mild all-aqueous phase method and serve as biological templates for the synthesis of AgNPs. The SFM-AgNPs exert dose- and time-dependent broad-spectrum antibacterial effects by inducing bacterial adhesion. The combination of SFM-AgNPs with antibiotics breaks the limitation of the antibacterial spectrum and achieves better efficacy with reduced antibiotic dosage. Using hyaluronic acid (HA) as the soluble matrix, the microneedle system containing SFM-AgNPs and anti-Gram-positive coccus drug (Mupirocin) inserts into the bacterial biofilms with sufficient strength, thereby effectively delivering the antibacterial agents and realizing good antibiofilm effect on Staphylococcus aureus-infected wounds. This work demonstrates the great potential for the development of novel therapeutic systems for eradicating bacterial biofilm infections.

Microfluidic fabrication of monodisperse microcapsules with gas cores.

A facile strategy for efficient and continuous fabrication of monodisperse gas-core microcapsules with controllable sizes and excellent ultrasound-induced burst performances is developed based on droplet microfluidics and interfacial polymerization. Monodisperse gas-in-oil-in-water (G/O/W) double emulsion droplets with a gas core and monomer-contained oil layer are fabricated in the upstream of a microfluidic device as templates, and then water-soluble monomers are added into the aqueous continuous phase in the downstream to initiate rapid interfacial polymerization at the O/W interfaces to prepare monodisperse gas-in-oil-in-solid (G/O/S) microcapsules with gas cores. The sizes of both microbubbles and G/O/W droplet templates can be precisely controlled by adjusting the gas supply pressure and the fluid flow rates. Due to the very thin shells of G/O/S microcapsules fabricated via interfacial polymerization, the sizes of the resultant G/O/S microcapsules are almost the same as those of the G/O/W droplet templates, and the microcapsules exhibit excellent deformable properties and ultrasound-induced burst performances. The proposed strategy provides a facile and efficient route for controllably and continuously fabricating monodisperse microcapsules with gas cores, which are highly desired for biomedical applications.

An antifouling gel-protected iridium needle sensor: Long-term, on-site monitoring of copper in seawater.

Copper (Cu), a natural micronutrient with ecotoxicological significance, is involved in the carbon and nitrogen cycles occurring in marine ecosystems. Here, we developed a novel, antifouling gel-protected iridium (Ir) needle electrode modified with gold nanoparticles (G-IrNS) for long-term continuous and steady Cu monitoring. The gel formed an efficient membrane that effectively prevented the fouling of the sensing surface and displayed anti-convective properties, ensuring that mass transport toward the sensor surface was wholly controlled via diffusion. The repeatability, reproducibility, and stability of G-IrNS showed that it was suitable for long-term and on-site monitoring of Cu in seawater. Cu concentrations were successfully measured via fixed-point continuous monitoring for >2 weeks and onboard continuous monitoring in Bohai Sea using one sensor. Moreover, the relationship between Cu concentrations measured on-site via G-IrNS and its dissolved concentration in Bohai Sea was evaluated. G-IrNS can be applied to other metal ions as well, especially for long-term automatic on-site monitoring, thereby providing a basis for further research.