Three kinds of ZnO nanocrystals (NCs) with different morphologies including multilayer disks, truncated hexagonal cones and short rods have been successfully synthesized by a solvothermal method without participation of surface capping agents. The water content in used N,N-dimethylformamide (DMF) solvent has been found to play an important role in controlling the formation of crystal planes, concentration of defects, and morphology of the ZnO NCs. The photocatalytic degradation of methyl orange in aqueous solution has been investigated in detail by employing the three kinds of ZnO NCs as photocatalysts under UV irradiation separately. Apparent reaction rates for different morphological ZnO NCs follow the order of short rods > truncated hexagonal cones > multilayer disks, implying strong photostability-dependent photocatalysis behavior of the ZnO NCs. Combined with photocorrosion, possible reasons for the difference of photocatalytic activity among them are discussed.
Chlortetracycline (CTC) is a widely used tetracycline antibiotic. However, the released CTC has become a manifest water pollutant. Herein, we report a ternary composite based on Ce(BTB)(H 2 O) ( 1 , H 3 BTB = 1,3,5-benzenetrisbenzoic acid), graphene oxide (GO), and iron oxide (Fe 3 O 4 ), denoted as 1 /GO/Fe 3 O 4 . In the composite, GO is used as the carrier to carry Fe 3 O 4 , and 1 as the active component is grafted onto magnetic GO. The addition of GO can accelerate electron migration and inhibit photoelectron-hole recombination. More importantly, the light absorption is also extended from the ultraviolet to the visible region. The ternary composite with H 2 O 2 shows remarkable photocatalytic degradation activity of CTC. Compared with pure 1 , the photocatalytic activity of the optimized composite improved by 5.4 times. Furthermore, 1 /GO/Fe 3 O 4 can be quickly recycled under an applied magnetic field and displayed outstanding stability and reusability. According to the radical trapping experiments and electron paramagnetic resonance results, hydroxyl radicals, superoxide radicals, and holes all contribute to the excellent photocatalytic activity. The possible catalytic mechanism of 1 /GO/Fe 3 O 4 is tentatively proposed. This work aims to explore the synergistic effect between metal-organic frameworks (MOFs) and GO, and provide a theoretical basis for MOFs-based composites to remove antibiotic contaminants in the environment.
Radiation therapy (XRT) has a well-established role in cancer treatment. Given the encouraging results on immunostimulatory effects, radiation has been increasingly used with immune-check-point inhibitors in metastatic disease, especially when immunotherapy fails due to tumor immune evasion. We hypothesized that using high-dose stereotactic radiation in cycles (pulses) would increase T-cell priming and repertoire with each pulse and build immune memory in an incremental manner. To prove this hypothesis, we studied the combination of anti-CTLA-4 and Pulsed radiation therapy in our 344SQ non-small cell lung adenocarcinoma murine model. Primary and secondary tumors were bilaterally implanted in 129Sv/Ev mice. In the Pulsed XRT group, both primary and secondary tumors received 12Gyx2 radiation one week apart, and blood was collected seven days afterwards for TCR repertoire analysis. As for the delayed-Pulse group, primary tumors received 12Gyx2, and after a window of two weeks, the secondary tumors received 12Gyx2. Blood was collected seven days after the second cycle of radiation. The immunotherapy backbone for both groups was anti-CTLA-4 antibody to help with priming. Treatment with Pulsed XRT + anti-CTLA-4 led to significantly improved survival and resulted in a delayed tumor growth, where we observed enhanced antitumor efficacy at primary tumor sites beyond XRT + anti-CTLA-4 treatment group. More importantly, Pulsed XRT treatment led to increased CD4 + effector memory compared to single-cycle XRT. Pulsed XRT demonstrated superior efficacy to XRT in driving antitumor effects that were largely dependent on CD4 + T cells and partially dependent on CD8 + T cells. These results suggest that combinatorial strategies targeting multiple points of tumor immune evasion may lead to a robust and sustained antitumor response.
Control cocatalyst location on a metal-free semiconductor to promote surface charge transfer for decreasing the electron-hole recombination is crucial for enhancing solar energy conversion. Based on the findings that some metals have an affinity for bonding with the specific atoms of polar semiconductors at a heterostructure interface, we herein control Pt deposition selectively on the Si sites of a micro-SiC photocatalyst surface via in-situ photo-depositing. The Pt-Si bond forming on the interface constructs an excellent channel, which is responsible for accelerating photo-electron transfer from SiC to Pt and then reducing water under visible-light. The hydrogen production is enhanced by two orders of magnitude higher than that of bare SiC, and 2.5 times higher than that of random-depositing nano-Pt with the same loading amount.
In this study, a highly efficient and stable phosphorus-doped Tungsten trioxide (P-WO3) photocatalyst was successfully synthesized using a combination of hydrothermal and post-calcination method. The microstructures, morphologies and optical properties of the obtained WO3 and P-WO3 samples were characterized. The results showed that P was uniformly doped into the WO3 lattice in a pentavalent-oxidation state (P5+). The charge carrier traps were also formed, which could accept the photoelectrons. Furthermore, the band gap energy was reduced from 2.4 to 2.33 ev. The photocatalytic performance of the obtained P-WO3 samples with different P concentrations were then tested by photocatalytic degradation of methyl blue (MB). It was found that the 6%-P-WO3 sample exhibited the highest photocatalytic activity, with 96% of MB being able to be degraded within 120 min, which was more than four times higher than that of the pure WO3. The practicality of the prepared P-WO3 was also evaluated using samples from two domestic wastewater treatment plants. The P-WO3 had a high photodegradation performance in treating low concentration of organic matters from real wastewater. The photocatalysis of P-WO3 could be mainly initiated by the production of hydroxyl radical (·OH) and photogenerated hole (h+).
Development of high-efficiency electrocatalysts for water splitting is a promising channel to produce clean hydrogen energy. Herein, we demonstrate that the combination of nitrogen-doped Mo2C and CoNi alloy to form a hybrid architecture is an effective way to produce hydrogen from electrochemical water splitting. Benefiting from a combination of mechanisms, the optimized N-Mo2C@CoNi-650 shows remarkable hydrogen evolution reaction (HER) activity with small overpotentials of 35, 123, and 220 mV to reach the current density of 10, 50, and 100 mA cm-2 in alkaline media, respectively, outperforming most previously reported HER electrocatalysts. The efficient electrocatalytic performance is ascribed to the highly exposed active sites, fast reaction kinetics, and improved charge-transfer steaming from the synergistic effect between each component. This work presents a new insight into designing and preparing highly efficient electrocatalysts toward the HER.
Background: To optimize [ 18 F] 9-fluoropropyl-(+)-dihydrotetrabenazine ( 18 F-FP-(+)-DTBZ) purification via solid-phase extraction (SPE) with combined cartridges to facilitate its widespread clinical application. Methods: A modified SPE purification method, employing Sep-Pak PS-2 and Sep-Pak C18 cartridges, was used for the preparation of 18 F-FP-(+)-DTBZ. This method was compared to the purification method of high-pressure liquid chromatography (HPLC) and SPE with one cartridge, following quality control test and positron emission tomography (PET) imaging in healthy volunteers and patients with parkinsn's disease (PD). Results: A SPE purification method integrating Sep-Pak PS-2 and Sep-Pak C18 cartridges was implemented successfully. The retention time of 18 F-FP-(+)-DTBZ purified by HPLC, SPE with Sep-Pak PS-2, SPE with Sep-Pak C18, and SPE with combined use of Sep-Pak PS-2 and Sep-Pak C18 cartridges was 8.7, 8.8, 8.7, and 8.9 min, respectively. Fewest impurity peak was detected in 18 F-FP-(+)-DTBZ purified by the SPE with combined use of Sep-Pak PS-2 and Sep-Pak C18 cartridges. This modified SPE purification method provided a satisfactory radiochemical yield of 29 ± 1.8% with radiochemical purity >99% and shortened synthesis time to 27 min. The brain uptake of 18 F-FP-(+)-DTBZ purified by the modified SPE was comparable to that purified by HPLC in both healthy volunteers and PD patients. Conclusions: A SPE method integrating Sep-Pak PS-2 and Sep-Pak C18 cartridges for purification of 18 F-FP-(+)-DTBZ may be highly suited to automatic synthesis for routine clinical applications, as it provides excellent radiochemical purity, high yield as well as operational simplicity.
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