Nanoscale drug-delivery systems (DDSs) have great promise in tumor diagnosis and treatment. Platelet membrane (PLTM) biomimetic DDSs are expected to enhance retention in vivo and escape uptake by ...macrophages, as well as minimizing immunogenicity, attributing to the CD47 protein in PLTM sends "don't eat me" signals to macrophages. In addition, P-selectin is overexpressed on the PLTM, which would allow a PLTM-biomimetic DDS to specifically bind to the CD44 receptors upregulated on the surface of cancer cells.
In this study, porous nanoparticles loaded with the anti-cancer drug bufalin (Bu) were prepared from a chitosan oligosaccharide (CS)-poly(lactic-co-glycolic acid) (PLGA) copolymer. These were subsequently coated with platelet membrane (PLTM) to form PLTM-CS-pPLGA/Bu NPs. The PLTM-CS-pPLGA/Bu NPs bear a particle size of ~ 192 nm, and present the same surface proteins as the PLTM. Confocal microscopy and flow cytometry results revealed a greater uptake of PLTM-CS-pPLGA/Bu NPs than uncoated CS-pPLGA/Bu NPs, as a result of the targeted binding of P-selectin on the surface of the PLTM to the CD44 receptors of H22 hepatoma cells. In vivo biodistribution studies in H22-tumor carrying mice revealed that the PLTM-CS-pPLGA NPs accumulated in the tumor, because of a combination of active targeting effect and the EPR effect. The PLTM-CS-pPLGA/Bu NPs led to more effective tumor growth inhibition over other bufalin formulations.
Platelet membrane biomimetic nanoparticles played a promising targeted treatment of cancer with low side effect.
High-current switching performance of ovonic threshold switching (OTS) selectors have successfully enabled the commercialization of high-density three-dimensional (3D) stackable phase-change memory ...in Intel’s 3D Xpoint technology. This bridges the huge performance gap between dynamic random access memory (DRAM) and Flash. Similar to phase-change memory, OTS uses chalcogenide-based materials, but whereas phase-change memory reversibly switches between a high-resistance amorphous phase and a low-resistance crystalline phase, OTS freezes in the amorphous phase. In this article, we review recent developments in OTS materials and their performance in devices, especially current density and selectivity. Advantages and challenges of OTS devices in the integration with the phase-change memory are discussed. We introduce the evolution of theoretical models for explaining the OTS behavior, including thermal runaway, field-induced nucleation, and generation/recombination of charge carriers.
Several previous studies have demonstrated the excellent antioxidant activity of fucoxanthin against oxidative stress which is closely related to the pathogenesis of liver diseases. The present work ...was to investigate whether fucoxanthin could protect human hepatic L02 cells against hydrogen peroxide- (H2O2-) induced oxidative damage. Its effects on H2O2-induced cell viability, lactate dehydrogenase (LDH) leakage, intracellular reduced glutathione, and reactive oxygen species (ROS) contents, along with mRNA and protein relative levels of the cytoprotective genes including Nrf2, HO-1, and NQO1, were investigated. The results showed that fucoxanthin could upregulate the mRNA and protein levels of the cytoprotective genes and promote the nuclear translocation of Nrf2, which could be inhibited by the PI3K inhibitor of LY294002. Pretreatment of fucoxanthin resulted in decreased LDH leakage and intracellular ROS content but enhanced intracellular reduced glutathione. Interestingly, pretreatment using fucoxanthin protected against the oxidative damage in a nonconcentration-dependent manner, with fucoxanthin of 5 μM demonstrating the optimal effects. The results suggest that fucoxanthin exerts cytoprotective effects against H2O2-induced oxidative damage in L02 cells, which may be through the PI3K-dependent activation of Nrf2 signaling.
Rational design of optimal bifunctional oxygen electrocatalyst with low cost and high activity is greatly desired for realization of rechargeable Zn–air batteries. Herein, we fabricate mesoporous ...thin-walled CuCo2O4@C with abundant nitrogen-doped nanotubes via coaxial electrospinning technique. Benefiting from high catalytic activity of ultrasmall CuCo2O4 particles, double active specific surface area of mesoporous nanotubes, and strong coupling with N-doped carbon matrix, the obtained CuCo2O4@C exhibits outstanding oxygen electrocatalytic activity and stability, in terms of a positive onset potential (0.951 V) for oxygen reduction reaction (ORR) and a low overpotential (327 mV at 10 mA cm–2) for oxygen evolution reaction (OER). Significantly, when used as cathode catalyst for Zn-air batteries, CuCo2O4@C also displays a low charge–discharge voltage gap (0.79 V at 10 mA cm–2) and a long cycling life (up to 160 cycles for 80 h). With desirable architecture and excellent electrocatalytic properties, the CuCo2O4@C is considered a promising electrocatalyst for Zn–air batteries.
An intramolecular dearomatization of indole derivatives based on visible-light-promoted 2+2 cycloaddition was achieved via energy transfer mechanism. The highly strained cyclobutane-fused angular ...tetracyclic spiroindolines, which were typically unattainable under thermal conditions, could be directly accessed in high yields (up to 99%) with excellent diastereoselectivity (>20:1 dr) under mild conditions. The method was also compatible with diverse functional groups and amenable to flexible transformations. In addition, DFT calculations provided guidance on the rational design of substrates and deep understanding of the reaction pathways. This process constituted a rare example of indole functionalization by exploiting visible-light-induced reactivity at the excited states.
To avoid the problems of low bandwidth or complex structure brought by conventional serial and parallel mechanisms, a novel decoupled robotic nanomanipulator (DRNM) with a hybrid configuration is ...conceived in this article to enable fast nanoscale manipulation. The proposed DRNM employs a new hybrid compliant structure to actuate the terminal platform and decouple the x - and y -axial motions. The unique hybrid mechanism is devised using two H-shaped parallelogram flexures that are assembled in a serial manner and actuated in a parallel manner, bringing in the merits of a flexible terminal platform, compact structure, good decoupling, and wide bandwidth in working directions. To enhance the dynamic positioning performance of the proposed DRNM, a run-to-run-position-forward-based integral controller that can handle the hysteresis nonlinearity of the piezoelectric actuator with adaptive zero-point parameter is further designed. The DRNM prototype is tested having an in-plane resonant frequency of 2005 Hz and a cross coupling of 0.88%. While tracking a circular trajectory with a diameter of 3 µm at a frequency of 20 Hz, the DRNM exhibits a maximum filtered tracking error of 4.3 nm.
In this study, we fabricated strontium-containing mesoporous bioactive glass (Sr-MBG) scaffolds with controlled architecture and enhanced mechanical strength using a three-dimensional (3-D) printing ...technique. The study showed that Sr-MBG scaffolds had uniform interconnected macropores and high porosity, and their compressive strength was ∼170 times that of polyurethane foam templated MBG scaffolds. The physicochemical and biological properties of Sr-MBG scaffolds were evaluated by ion dissolution, apatite-forming ability and proliferation, alkaline phosphatase activity, osteogenic expression and extracelluar matrix mineralization of osteoblast-like cells MC3T3-E1. The results showed that Sr-MBG scaffolds exhibited a slower ion dissolution rate and more significant potential to stabilize the pH environment with increasing Sr substitution. Importantly, Sr-MBG scaffolds possessed good apatite-forming ability, and stimulated osteoblast cells’ proliferation and differentiation. Using dexamethasone as a model drug, Sr-MBG scaffolds also showed a sustained drug delivery property for use in local drug delivery therapy, due to their mesoporous structure. Therefore, the 3-D printed Sr-MBG scaffolds combined the advantages of Sr-MBG such as good bone-forming bioactivity, controlled ion release and drug delivery and enhanced mechanical strength, and had potential application in bone regeneration.
Accurate etiology diagnosis is crucial for central nervous system infections (CNS infections). The diagnostic value of metagenomic next-generation sequencing (mNGS), an emerging powerful platform, ...remains to be studied in CNS infections.
We conducted a single-center prospective cohort study to compare mNGS with conventional methods including culture, smear and etc. 248 suspected CNS infectious patients were enrolled and clinical data were recorded.
mNGS reported a 90.00% (9/10) sensitivity in culture-positive patients without empirical treatment and 66.67% (6/9) in empirically-treated patients. Detected an extra of 48 bacteria and fungi in culture-negative patients, mNGS provided a higher detection rate compared to culture in patients with (34.45% vs. 7.56%, McNemar test, p < 0.0083) or without empirical therapy (50.00% vs. 25.00%, McNemar test, p > 0.0083). Compared to conventional methods, positive percent agreement and negative percent agreement was 75.00% and 69.11% separately. mNGS detection rate was significantly higher in patients with cerebrospinal fluid (CSF) WBC > 300 * 10
/L, CSF protein > 500 mg/L or glucose ratio ≤ 0.3. mNGS sequencing read is correlated with CSF WBC, glucose ratio levels and clinical disease progression.
mNGS showed a satisfying diagnostic performance in CNS infections and had an overall superior detection rate to culture. mNGS may held diagnostic advantages especially in empirically treated patients. CSF laboratory results were statistically relevant to mNGS detection rate, and mNGS could dynamically monitor disease progression.
Time‐dependent kinetics of xylem Na+ loading was investigated using a large number of barley genotypes contrasting in their salinity tolerance. Salt‐sensitive varieties were less efficient in ...controlling xylem Na+ loading and showed a gradual increase in the xylem Na+ content over the time. To understand underlying ionic and molecular mechanisms, net fluxes of Ca2+, K+ and Na+ were measured from the xylem parenchyma tissue in response to H2O2 and ABA; both of them associated with salinity stress signalling. Our results indicate that NADPH oxidase‐mediated apoplastic H2O2 production acts upstream of the xylem Na+ loading and is causally related to ROS‐inducible Ca2+ uptake systems in the root stelar tissue. It was also found that ABA regulates (directly or indirectly) the process of Na+ retrieval from the xylem and the significant reduction of Na+ and K+ fluxes induced by bumetanide are indicative of a major role of chloride cation co‐transporter (CCC) on xylem ion loading. Transcript levels of HvHKT1;5_like and HvSOS1_like genes in the root stele were observed to decrease after salt stress, while there was an increase in HvSKOR_like gene, indicating that these ion transporters are involved in primary Na+/K+ movement into/out of xylem.
Hierarchical Fe3O4@polypyrrole nanocages constructed with thin nanosheets are synthesized via a reduction and in situ polymerization route. They exhibit a stable cycling performance (650 mA h g−1 ...capacity at 2000 mA g−1 after 500 cycles) and superior rate capability (reversible capabilities of 1120, 950, 796, 657, and 490 mA h g−1 at 100, 300, 1000, 2500, and 5000 mA g−1, respectively).
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