We report herein an investigation of carbazole-based cyanine, (E)-4-(2-(9-(2-(2-methoxyethoxy)ethyl)-9H-carbazol-3-yl)-vinyl)-1-methyl-quinolin-1-iumiodide (SLM), as an effective theranostic agent for Alzheimer's disease (AD). This cyanine exhibited desirable multifunctional and biological properties, including amyloid-β (Aβ)-oligomerization inhibition, blood-brain barrier permeability, low neurotoxicity, neuroprotective effect against Aβ-induced toxicities, high selectivity and strong binding interactions with Aβ peptide/species, good biostability, as well as strong fluorescence enhancement upon binding to Aβ species for diagnosis and therapy of AD. This cyanine has been successfully applied to perform near-infrared in vivo imaging of Aβ species in transgenic AD mouse model. The triple transgenic AD mice intraperitoneally treated with SLM showed significant recovery of cognitive deficits. Furthermore, those SLM-treated mice exhibited a substantial decrease in both of oligomeric Aβ contents and tau proteins in their brain, which was attributed to the induction of autophagic flux. These findings demonstrated for the first time that SLM is an effective theranostic agent with in vivo efficacy for diagnosis and treatment of AD in mouse models.
The hydrogenation of carbon dioxide (CO2) to produce light olefins is one of the most promising ways to utilize CO2 in power plant flue gas. However, the low concentration of CO2 (~10%) and the existence of water steam in the flue gas pose great challenges for the catalyst design. To address these problems, we introduced a Mg promoter and hydrophobic component into the Fe-based catalyst to improve the CO2 adsorption capacity and weaken the negative effects of water. The yield of light olefins on an optimized multifunctional Fe-based catalyst increased by 37% in low-concentration CO2 hydrogenation with water steam. A variety of characterizations proved that the Mg promoter played critical roles in regulating the adsorption capacity of CO2, increasing the surface electron density of Fe species, and promoting the formation of iron carbide active sites. The hydrophobic component mainly contributed to constraining the oxidation of iron carbides via water steam. It benefited from the rational design of the catalyst, showing how our multifunctional Fe-based catalyst has great potential for practical application in CO2 utilization.
Abstract Due to the heterogeneity among the States in the US, predicting COVID-19 trends and quantitatively assessing the effects of government testing capability and control measures need to be done via a State-by-State approach. We develop a comprehensive model for COVID-19 incorporating time delays and population movements. With key parameter values determined by empirical data, the model enables the most likely epidemic scenarios to be predicted for each State, which are indicative of whether testing services and control measures are vigorous enough to contain the disease. We find that government control measures play a more important role than testing in suppressing the epidemic. The vast disparities in the epidemic trends among the States imply the need for long-term placement of control measures to fully contain COVID-19.
Cu–ZnO catalysts are widely studied for the direct hydrogenation of CO2 to methanol for high activity. However, despite the widespread research, promoting the intrinsic activity of active sites remains a contentious topic. We here report a facile strategy to manufacture ZnFe2O4 spinel-supported Cu catalysts with a tuneable size of Cu nanoparticles for selective methanol synthesis from CO2 hydrogenation. The optimized 33Cu/ZnFe-0.5 catalyst exhibits a high methanol selectivity of 71.6% at a CO2 conversion of 9.4% at 260 °C and 4.5 MPa. Increasing the Zn/Fe ratio decreases the selectivity of methanol at the same CO2 conversion and especially at lower CO2 conversions. The generation of extra Cu+ sites at Cu–spinel interfaces instead of Cu–ZnOx interfaces markedly inhibits the reverse water gas shift reaction during CO2 hydrogenation. The roles of Cu sites in methanol synthesis from CO2/H2 are that the Cu–ZnO interfaces act as the active sites for speeding up the production of methanol, while the Cu+ sites at the Cu–spinel interfaces act as synergy sites for improving the methanol selectivity and activity of each Cu–ZnO site.
Dielectric barrier discharge (DBD) is utilized to decompose xylene vapor in mobile gas under normal atmospheric pressure. The plasma is generated by an AC power source with a frequency of 6 kHz. In the experiment, the discharge power on the DBD reactor was calculated by a Lissajous figure, and the specific input energy (SIE) of different discharge voltage or residence time was obtained. The concentrations of xylene, carbon monoxide and carbon dioxide in the gas were analyzed by gas chromatography. The spectra of DBD were diagnosed using a spectrometer. We calculated the conversion rate (CR), mineralization rate (MR) and carbon dioxide selectivity. The relationship between these quantities and the SIE was analyzed. The experimental results show that high concentration xylene can be decomposed mostly by DBD plasma. The CR can reach as high as 90% with the main product of carbon dioxide.
The multifunctional theranostic cyanine SLCOOH, capable of real-time imaging of Aβ contents in vivo and targeting multiple pathological pathways or mechanisms of neurodegeneration, was unambiguously demonstrated.
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