Integrated Microfluidic Chip Technology for Copper Ion Detection Using an All-Solid-State Ion-Selective Electrode

This study involved the preparation of an all-solid-state ion-selective electrode (ASS-ISE) with copper and a poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate (PEDOT/PSS) conversion layer through electrode deposition. The morphology of the PEDOT/PSS film was characterized, and the performance of the copper ion-selective film was optimized. Additionally, a microfluidic chip for the ASS-ISE with copper was designed and prepared. An integrated microfluidic chip test system with an ASS-ISE was developed using a self-constructed potential detection device. The accuracy of the system was validated through comparison testing with atomic absorption spectrophotometry (AAS). The experimental findings indicate that the relative standard deviation (RSD) of the integrated ASS-ISE with the copper microfluidic chip test system is 4.54%, as compared to the industry standard method. This value complies with the stipulated requirement of an RSD ≤ 5% in DL/T 955-2016.

Phase-Change Based Oxygen Carriers Improve Acute Cerebral Hypoxia

Stroke is the second leading cause of death worldwide, and hypoxia is a major crisis of the brain after stroke. Therefore, providing oxygen to the brain microenvironment can effectively protect neurons from damage caused by cerebral hypoxia. However, there is a lack of timely and effective means of oxygen delivery clinically to the brain for acute cerebral hypoxia. Here, a phase-change based nano oxygen carrier is reported, which can undergo a phase change in response to increasing temperature in the brain, leading to oxygen release. The nano oxygen carrier demonstrate intracerebral oxygen delivery capacity and is able to release oxygen in the hypoxic and inflammatory region of the brain. In the acute ischemic stroke mouse model, the nano oxygen carrier can effectively reduce the area of cerebral infarction and decrease the level of inflammation triggered by cerebral hypoxia. By taking advantage of the increase in temperature during cerebral hypoxia, phase-change oxygen carrier proposes a new intracerebral oxygen delivery strategy for reducing acute cerebral hypoxia.

Inhibitory effect of bilobalide on Staphylococcus aureus von Willebrand factor-binding protein and its therapeutic effect in mice with pneumonia

AIMS

Disabling bacterial virulence with small molecules has been proposed as a potential strategy to prevent bacterial pathogenicity. The von Willebrand factor-binding protein of Staphylococcus aureus was identified previously as a key virulence determinant. Our objective was to discover a von Willebrand-factor binding protein (vWbp) inhibitor distinct from the antibiotics used to prevent infections resulting from S. aureus.

METHODS AND RESULTS

Using coagulation assays, we found that the sesquiterpene trilactone bilobalide blocks coagulation mediated by vWbp, but has no impact on the growth of S. aureus at a concentration of 128 μg ml-1. Moreover, a mouse model of pneumonia caused by S. aureus indicated that bilobalide could attenuate S. aureus virulence in vivo. This effect is achieved not by interfering with the expression of vWbp but by binding to vWbp, as demonstrated by western blotting, thermal shift assays, and fluorescence quenching assays. Using molecular dynamic simulations and point mutagenesis analysis, we identified that the Q17A and R453A residues are key residues for the binding of bilobalide to vWbp.

CONCLUSIONS

Overall, we tested the ability of bilobalide to inhibit S. aureus infections by targeting vWbp and explored the potential mechanism of this activity.

Gas-phase advanced oxidation (GPAO) for benzene-containing gas by an ultraviolet irradiation/hydrogen peroxide vapour (UV/[H2O2]g) process

Hydrogen peroxide (H₂O₂) is a remarkably strong oxidant, and its vapour ([H₂O₂]_g) has further advantages, such as a low cost and good light transmission. However, there has been very little research on its removal through gas-phase advanced oxidation (GPAO). In the present study, the photochemical oxidation of a gas that contains a series of benzene derivatives using ultraviolet (UV) irradiation and [H₂O₂]_g was investigated in a transparent bag made of fluorinated ethylene propylene (FEP). UV and [H₂O₂]_g barely reduced the pollutant within 5 h when used alone, and the reactant was also stable. When the pollutant concentration was high (248 to 756 mg/m³) and the residence time was short (3 s) compared with related studies on the removal of benzene, toluene and xylene, the apparent removal rate by UV/[H₂O₂]_g/(powder active carbon, PAC) was higher than when other methods (UV/[H₂O₂]_g, UV/[H₂O₂]_g/TiO₂ and UV/[H₂O₂]_g/ZnO), were used. However, it was found that the mineralization by UV/[H₂O₂]_g significantly decreased, which in turn decreased the conductivity after the reaction. Increasing the pollutant concentration and the pH of the H₂O₂ had a negative effect on the treatment, but the UV radiation had a positive effect at powers of up to 40 W. In addition, the characteristic absorbance of three benzene derivatives showed that the key structure of the pollutant molecules was damaged during GPAO.

Response of soil organic carbon fractions, microbial community composition and carbon mineralization to high-input fertilizer practices under an intensive agricultural system

Microbial mechanisms associated with soil organic carbon (SOC) decomposition are poorly understood. We aim to determine the effects of inorganic and organic fertilizers on soil labile carbon (C) pools, microbial community structure and C mineralization rate under an intensive wheat-maize double cropping system in Northern China. Soil samples in 0–10 cm layer were collected from a nine-year field trial involved four treatments: no fertilizer, CK; nitrogen (N) and phosphorus (P) fertilizers, NP; maize straw combined with NP fertilizers, NPS; and manure plus straw and NP fertilizers, NPSM. Soil samples were analyzed to determine labile C pools (including dissolved organic C, DOC; light free organic C, LFOC; and microbial biomass C, MBC), microbial community composition (using phospholipid fatty acid (PLFA) profiles) and SOC mineralization rate (from a 124-day incubation experiment). This study demonstrated that the application of chemical fertilizers (NP) alone did not alter labile C fractions, soil microbial communities and SOC mineralization rate from those observed in the CK treatment. Whereas the use of straw in conjunction with chemical fertilizers (NPS) became an additional labile substrate supply that decreased C limitation, stimulated growth of all PLFA-related microbial communities, and resulted in 53% higher cumulative mineralization of C compared to that of CK. The SOC and its labile fractions explained 78.7% of the variance of microbial community structure. Further addition of manure on the top of straw in the NPSM treatment did not significantly increase microbial community abundances, but it did alter microbial community structure by increasing G+/G- ratio compared to that of NPS. The cumulative mineralization of C was 85% higher under NPSM fertilization compared to that of CK. Particularly, the NPSM treatment increased the mineralization rate of the resistant pool. This has to be carefully taken into account when setting realistic and effective goals for long-term soil C stabilization.