An amperometric glucose biosensor was prepared using polyaniline (PANI) and chitosan-coupled carbon nanotubes (CS-CNTs) as the signal amplifiers and glucose oxidase (GOD) as the glucose detector on a ...gold electrode (the Au-g-PANI-c-(CS-CNTs)-GOD biosensor). The PANI layer was prepared via oxidative graft polymerization of aniline from the gold electrode surface premodified by self-assembled monolayer of 4-aminothiophenol. CS-CNTs were covalently coupled to the PANI-modified gold substrate using glutaradehyde as a bifunctional linker. GOD was then covalently bonded to the pendant hydroxyl groups of chitosan using 1,4-carbonyldiimidazole as the bifunctional linker. The surface functionalization processes were ascertained by X-ray photoelectron spectroscopy (XPS) analyses. The field emission scanning electron microscopy (FESEM) images of the Au-g-PANI-c-(CS-CNTs) electrode revealed the formation of a three-dimensional surface network structure. The electrode could thus provide a more spatially biocompatible microenvironment to enhance the amount and biocatalytic activity of the immobilized enzyme and to better mediate the electron transfer. The resulting Au-g-PANI-c-(CS-CNTs)-GOD biosensor exhibited a linear response to glucose in the concentration range of 1−20 mM, good sensitivity (21 μA/(mM·cm2)), good reproducibility, and retention of >80% of the initial response current after 2 months of storage.
Nearly monodispersed silica−poly(methacrylic acid) (SiO2−PMAA) core−shell microspheres were synthesized by distillation-precipitation polymerization from 3-(trimethoxysilyl)propylmethacrylate-silica ...(SiO2-MPS) particle templates. SiO2−PMAA−SiO2 trilayer hybrid microspheres were subsequently prepared by coating of an outer layer of SiO2 on the SiO2−PMAA core−shell microspheres in a sol−gel process. pH-Responsive PMAA hollow microspheres with flexible (deformable) shells were obtained after selective removal of the inorganic SiO2 core from the SiO2−PMAA core−shell microspheres by HF etching. The pH-responsive properties of the PMAA hollow microspheres were investigated by dynamic laser scattering (DLS). On the other hand, concentric and rigid hollow silica microspheres were prepared by selective removal of the PMAA interlayer from the SiO2−PMAA−SiO2 trilayer hybrid microspheres during calcination. The hybrid composite microspheres, pH-sensitive hollow microspheres, and concentric hollow silica microspheres were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray (EDX) analysis.
A solution-processable graphene oxide (GO)−polymer complex, consisting of GO nanosheets with covalently grafted poly(tert-butyl acrylate) (PtBA) brushes, was prepared via surface-initiated atom ...transfer radical polymerization (ATRP). The grafted hydrophobic polymer brushes substantially enhance the solubility of GO in organic solvents, and the GO-g-PtBA nanosheets can form a uniform and stable dispersion in toluene. The functionalized GO nanosheets can also be integrated into an electroactive polymer matrix. Bistable electrical conductivity switching behavior and a nonvolatile electronic memory effect were demonstrated in a composite thin film of poly(3-hexylthiophene) (P3HT) containing 5 wt % GO-g-PtBA in an Al/GO-g-PtBA+P3HT/ITO sandwich structure (ITO = indium−tin oxide). Hydrolysis of GO-g-PtBA produces water-dispersible GO-g-PAAc (PAAc = poly(acrylic acid)) nanosheets and allows the preparation of gold nanoparticle-decorated GO-g-PAAc nanofilms from aqueous dispersions.
Learning is thought to involve changes in glutamate receptors at synapses, submicron structures that mediate communication between neurons in the central nervous system. Due to their small size and ...high density, synapses are difficult to resolve in vivo, limiting our ability to directly relate receptor dynamics to animal behavior. Here we developed a combination of computational and biological methods to overcome these challenges. First, we trained a deep-learning image-restoration algorithm that combines the advantages of ex vivo super-resolution and in vivo imaging modalities to overcome limitations specific to each optical system. When applied to in vivo images from transgenic mice expressing fluorescently labeled glutamate receptors, this restoration algorithm super-resolved synapses, enabling the tracking of behavior-associated synaptic plasticity with high spatial resolution. This method demonstrates the capabilities of image enhancement to learn from ex vivo data and imaging techniques to improve in vivo imaging resolution.
Expression of E-cadherin, a hallmark of epithelial-mesenchymal transition (EMT), is often lost due to promoter DNA methylation in basal-like breast cancer (BLBC), which contributes to the metastatic ...advantage of this disease; however, the underlying mechanism remains unclear. Here, we identified that Snail interacted with Suv39H1 (suppressor of variegation 3-9 homolog 1), a major methyltransferase responsible for H3K9me3 that intimately links to DNA methylation. We demonstrated that the SNAG domain of Snail and the SET domain of Suv39H1 were required for their mutual interactions. We found that H3K9me3 and DNA methylation on the E-cadherin promoter were higher in BLBC cell lines. We showed that Snail interacted with Suv39H1 and recruited it to the E-cadherin promoter for transcriptional repression. Knockdown of Suv39H1 restored E-cadherin expression by blocking H3K9me3 and DNA methylation and resulted in the inhibition of cell migration, invasion and metastasis of BLBC. Our study not only reveals a critical mechanism underlying the epigenetic regulation of EMT, but also paves a way for the development of new treatment strategies against this disease.
•Analysis of the longitudinal Kerr contrast in a wide-field magneto-optical Kerr.•All directional in-plane magnetisation reversal loops measurement.•In-plane mechanical adjustment free anisotropy ...measurements.•Anisotropy of iron oxide thin films.•Stress induced anisotropy change of NiFe thin films.s
An advanced wide-field Kerr microscopy and magnetometry approach for the investigation of magnetic anisotropy in magnetic films is demonstrated. We have analytically analysed the longitudinal Kerr contrast in a wide-field magneto-optical Kerr microscope, specifically its dependence on the light polarisation direction and the plane of incidence and verified it experimentally. While normally the sensitivity direction (i.e. the direction of maximum contrast for antiparallel domains) of the longitudinal Kerr effect is along the plane of incidence for both, p - and s-polarized light, we found a deviation of the sensitivity direction from the incidence plane for p-polarised light. Based on a multi-component Kerr imaging technique we have developed a fully automated procedure for the measurement of magnetisation reversal loops along arbitrary in-plane field directions for magnetic films with in-plane anisotropy that does not require any mechanical adjustment of the system or sample displacement. The method is applied to the investigation of the magnetic anisotropy of a sputtered iron thin film. Additionally, a sample holder was introduced, which allows for the application of mechanical stress onto magnetic films due to substrate bending, and its applicability to the stress manipulation of the anisotropy direction was demonstrated for a nickel-iron film.
Highlights • Laminin expression was increased in the vasogenic edema lesions following SE. • Laminin over-expression was not correlated with astroglial death. • Laminin expression was reduced during ...recovery of vasogenic edema. • Inhibition of vasogenic edema by BQ788 attenuated laminin over-expression. • Laminin over-expression may play a role in recovery of vascular damage.
Tunable electromagnets and corresponding devices, such as magnetic lenses or stigmators, are the backbone of high-energy charged particle optical instruments, such as electron microscopes, because ...they provide higher optical power, stability, and lower aberrations compared to their electric counterparts. However, electromagnets are typically macroscopic (super-)conducting coils, which cannot generate swiftly changing magnetic fields, require active cooling, and are structurally bulky, making them unsuitable for fast beam manipulation, multibeam instruments, and miniaturized applications. Here, we present an on-chip microsized magnetic charged particle optics realized via a self-assembling micro-origami process. These micro-electromagnets can generate alternating magnetic fields of about ±100 mT up to a hundred MHz, supplying sufficiently large optical power for a large number of charged particle optics applications. That particular includes fast spatiotemporal electron beam modulation such as electron beam deflection, focusing, and wave front shaping as required for stroboscopic imaging.
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