Efforts have been devoted to achieving a highly efficient artificial synthesis of ammonia (NH3). Reported herein is a novel Fe‐MoS2 catalyst with Fe atomically dispersed onto MoS2 nanosheets, imitating natural nitrogenase, to boost N2 electroreduction into NH3 at room temperature. The Fe‐MoS2 nanosheets exhibited a faradic efficiency of 18.8 % with a yield rate of 8.63 μgNH3
mgcat.−1 h−1 for NH3 at −0.3 V versus the reversible hydrogen electrode. The mechanism study revealed that the electroreduction of N2 was promoted and the competing hydrogen evolution reaction was suppressed by decorating the edge sites of S in MoS2 with the atomically dispersed Fe, resulting in high catalytic performance for the electroreduction of N2 into NH3. This work provides new ideas for the design of catalysts for N2 electroreduction and strengthens the understanding about N2 activation over Mo‐based catalysts.
Abstract:The development of H 2 gas sensors is important for H 2 production as af uel. In this work, aZ nO@ZIF-8c oreshell nanorod film is designed and synthesized as ag as sensor through af acile solutiond eposition process. This film shows an excellent selective response for H 2 over CO. By fine-tuning the reaction conditions, aZ nO@ZIF-8 core-shell structure with at hin, fine-grain, porousZ IF-8 shell is obtained. Owing to the facile H 2 penetration through the ZIF-8 thin shell ( % 110nm) and the increased oxygen vacancies for the complex film, the ZnO@ZIF-8 nanorod film shows ah igher H 2 sensitivity than ar aw ZnO nanorod film. More importantly,t he ZnO@ZIF-8 nanorod film shows no response for CO at 200 8C. Because of the fine-grain confinemento f the porous ZIF-8 shell (< 140 nm), the molecular sieving effect is strengthened, which allows the effective separation of H 2 over CO. This work providesapromising strategy for the design of high-performance H 2 sensors.
A microporous metal–organic framework with a suitable pore/cage-like structure of a precise size matching well with the xenon atom exhibits a commensurate adsorption phenomenon of Xe and superior performance for the removal of Xe from nuclear fuel reprocessing plants.
Breast cancer (BC) is a leading cause of cancer-related death in women. Adjuvant systemic chemotherapies are effective in reducing risks of recurrence and have contributed to reduced BC mortality. Although targeted adjuvant treatments determined by biomarkers for endocrine and HER2-directed therapies are largely successful, predicting clinical benefit from chemotherapy is more challenging. Drug resistance is a major reason for treatment failures. Efforts are ongoing to find biomarkers to select patients most likely to benefit from chemotherapy. Importantly, cell surface biomarkers CD44+/CD24− are linked to drug resistance in some reports, yet underlying mechanisms are largely unknown. This study focused on the potential role of CD24 expression in resistance to either docetaxel or doxorubicin in part by the use of triple-negative BC (TNBC) tissue microarrays. In vitro assays were also done to assess changes in CD24 expression and differential drug susceptibility after chemotherapy. Further, mouse tumor xenograft studies were done to confirm in vitro findings. Overall, the results show that patients with CD24-positive TNBC had significantly worse overall survival and disease-free survival after taxane-based treatment. Also, in vitro cell studies show that CD44+/CD24+/high cells are more resistant to docetaxel, while CD44+/CD24−/low cells are resistant to doxorubicin. Both in vitro and in vivo studies show that cells with CD24-knockdown are more sensitive to docetaxel, while CD24-overexpressing cells are more sensitive to doxorubicin. Further, mechanistic studies indicate that Bcl-2 and TGF-βR1 signaling via ATM-NDRG2 pathways regulate CD24. Hence, CD24 may be a biomarker to select chemotherapeutics and a target to overcome TNBC drug resistance.
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