We study the condition of the occurrence of the rim instability in the solvent-induced dewetting process. Our experimental results show that the film thickness not only greatly influences the occurrence of the rim instability, but also influences the wavelength lambda as characterized by the undulation of the deformed contact line. The molecular weight of polymer does not almost influence the occurrence of the rim instability and the wavelength lambda. The wavelength lambda is proportional to the width of the rim in the rim instability region. The receding contact angle theta of polymer solutions on substrates in the dewetting process is an important factor to influence the rim instability in the solvent-induced dewetting.
Mycotoxin contamination threatens health and life of humans and animals throughout the food supply chains. Many of the mycotoxins have been proven to be carcinogens, teratogens and mutagens. The reliable and sensitive sensing methods are requested to monitor mycotoxin contamination. Advanced sensors based on antibodies or aptamers boast the advantages of high sensitivity and rapidity, and have been used in the mycotoxin sensing. These sensors are miniaturized, thereby lowering costs, and are applicable to high-throughput modes. In this work, the latest developments in sensing strategies for mycotoxin determination were critically discussed. Optical and electrochemical sensing modes were compared. The sensing methods for single mycotoxin or multiple mycotoxins in food samples were reviewed, along with the challenges and the future of antibody or aptamer-based sensors. This work might promote academic studies and industrial applications for mycotoxin sensing.
Background Tetramethylpyrazine (TMP) is a natural alkaloid compound with antioxidant and neuroprotective effects. We hypothesized that TMP could exert neuroprotective effects by inhibiting ferroptosis through modulating iron metabolism, but its mechanism is unclear. Through in vivo and in vitro experiments, we have explored how TMP can regulate neurons’ iron metabolism through the NRF2/ARE pathway to Inhibit ferroptosis. Methods In the in vivo experiment, the effects of TMP on nerve function and secondary spinal cord injury were observed through behavioral tests and morphology staining. Transmission electron microscopy, molecular biology tests and immunofluorescence staining were used to investigate the role of TMP in the regulation of iron metabolism and ferroptosis through the Nrf2/ARE pathway. Using in vitro experiments to investigate the mechanism of TMP in inhibiting ferroptosis through the Nrf2/ARE pathway. Results Firstly, through in vivo experiments, we found that TMP improves motor function of rats with spinal cord injury, reduces spinal cord tissue damage and nerve cell death caused by secondary injury. Moreover, neuronal death and the formation of spinal cord cavities are inhibited by TMP. By regulating lipid peroxidation, TMP can inhibit mitochondrial damage and reduce ROS accumulation. Our study also demonstrated that TMP regulates iron metabolism through the NRF2/ARE pathway to inhibit ferroptosis and repair spinal cord injury. To further explore the regulatory mechanisms of TMP we down-regulating Nrf2 expression in subsequent in vitro experiments. We find that a key ferroptosis pathway, lipid peroxidation, can be regulated by TMP. Additionally, TMP inhibits iron overload-mediated ferroptosis by increasing Nrf2 transcriptional activity. Conclusion A regulatory effect of TMP on the NRF2/ARE pathway was found in both in vitro and in vivo experiments. It promotes the transcription and translation of iron metabolizing and antioxidant molecules. Our study explored the inhibitory effect of TMP on ferroptosis from the iron metabolism pathway and provided new ideas for the treatment of SCI.
We describe a new fluorescence turn-on sensor for homogeneous detection of aflatoxin B1 (AFB1), a potent low molecular weight mycotoxin. A key innovation is the binding-induced intramolecular interaction involving the following two sets of probes: (1) a gold nanoparticle (AuNP) immobilized with hundreds of assistant oligonucleotides (AO) and dozens of anti-AFB1 monoclonal antibodies, and (2) the AFB1-BSA (BSA = bovine serum albumin) antigen conjugated with fluorophore-labeled signal oligonucleotides (SO) that contained a short sequence complementary to AO. Specific binding of AFB1-BSA to the antibody brought the fluorophore very close to the surface of the AuNP through a stable intramolecular hybridization between AO and SO, resulting in efficient quenching of fluorescence. The improved fluorescence quenching substantially reduced the background, due to the binding-induced intramolecular hybridization, and improved the signal-to-background ratio by 390%. In the presence of AFB1 in a sample, competitive binding of AFB1 in the sample to the antibodies immobilized on the AuNP caused the release of the fluorophore-labeled AFB1-BSA from the AuNP, turning on fluorescence. A detection limit of 2.3 nM was achieved, which meets the requirement for AFB1 detection at regulatory levels. Analyses of rice samples using this assay showed recoveries of 86–102%. Incorporating appropriate antibody probes could extend the assay to the detection of other small molecules.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Ultrafine-grained pure (UFG) titanium processed by equal channel angular pressing possesses mechanical properties comparable to those of Ti-6Al-4V and features more favorable friction resistance, biocompatibility, and corrosion resistance than does commercially pure (CP) titanium. Nevertheless, UFG titanium is still a bio-inert material with a lack of bone-inducing ability. Here, TiO2-hydroxyapatite (TiO2-HA) coatings were fabricated on CP titanium and UFG titanium through combining micro-arc oxidation and hydrothermal treatment together to improve their cytocompatibility. The results indicate that, compared with conventional coatings that use CP titanium as the substrate, such coatings formed on the UFG titanium possess additional hydrophilicity and in vitro cytocompatibility. The fantastic hierarchical structure of the UFG TiO2-HA coating (UG-MH coating), including microscale and nanoscale pores and short column-shaped and sheet-shaped HA grains with varying geometric shapes, excellent hydrophilicity, and high polar force, enhances the mutual effects between the osteoblasts and titanium implant since it provides an adequate microenvironment for the ingrowth of osteoblasts, inducing osteoblast adhesion, proliferation, and differentiation. The UG-MH coating has a synergistic effect due to its fantastic hydrophilic hierarchical structure and high polar force on the up-regulated expression of cytoskeletal actin proteins as well as osteocalcin, protein kinase C (PKC), nuclear factor of activated T-cells (NFAT), and Wnt5, enabling osteoblasts to differentiate via the Wnt calcium-dependent signaling pathway. This study highlights the idea that the modified UFG titanium will be more suitable than CP titanium in dental and orthopedic applications.
Designing highly stable and reusable catalytic systems based on Au nanoparticles (NPs) is a significant challenge in nanocatalysis research. Here, we have fabricated polyvinyl alcohol (PVA) nanofibrous mat/Au NP composite catalysts with NPs in uniform size and good distribution by use of a developed in situ growth approach. In this method, Au seeds were first adsorbed on PVA nanofibrous mat surfaces rather than on relatively large Au NPs and then used to grow NPs in Au seed solution; thus, the steric hindrance effect was alleviated and a high loading was used for Au NPs up to 11 wt %. Strong interfacial interactions between the Au NPs and the PVA nanofibrous mats due to introducing a large number of hydrogen bonds provide high thermal stability for the PVA side chains, long-term catalytic stability, and excellent reusability. Consequently, the proposed in situ grown PVA/Au NP nanofibrous mats produce high catalytic activity for at least 15 cycles over a 30 d period. This work provides a potential approach for fabricating highly stable and reusable metal NPs on polymer nanofibrous mats to facilitate a wide variety of applications.
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