RESUMEN
Thermally activated ultrafast diffusion, collision and combination of metal atoms comprise the fundamental processes of synthesizing burgeoning subnanometer metal clusters for diverse applications. However, so far, no method has allowed the kinetically controllable synthesis of subnanometer metal clusters without compromising metal loading. Herein, we have developed, for the first time, a graphene-confined ultrafast radiant heating (GCURH) method for the synthesis of high-loading metal cluster catalysts in microseconds, where the impermeable and flexible graphene acts as a diffusion-constrained nanoreactor for high-temperature reactions. Originating from graphene-mediated ultrafast and efficient laser-to-thermal conversion, the GCURH method is capable of providing a record-high heating and cooling rate of â¼109°C/s and a peak temperature above 2000°C, and the diffusion of thermally activated atoms is spatially limited within the confinement of the graphene nanoreactor. As a result, due to the kinetics-dominant and diffusion-constrained condition provided by GCURH, subnanometer Co cluster catalysts with high metal loading up to 27.1 wt% have been synthesized by pyrolyzing a Co-based metal-organic framework (MOF) in microseconds, representing one of the highest size-loading combinations and the quickest rate for MOF pyrolysis in the reported literature. The obtained Co cluster catalyst not only exhibits an extraordinary activity similar to that of most modern multicomponent noble metal counterparts in the electrocatalytic oxygen evolution reaction, but is also highly convenient for catalyst recycling and refining due to its single metal component. Such a novel GCURH technique paves the way for the kinetically regulated, limited diffusion distance of thermally activated atoms, which in turn provides enormous opportunities for the development of sophisticated and environmentally sustainable metal cluster catalysts.
RESUMEN
The present study evaluated the effectiveness and safety of Xuanfei Baidu Decoction(XFBD) for severe cases with coronavirus disease 2019(COVID-19).Forty-one patients(diagnosed as severe or critical type) admitted to Hubei Provincial Hospital of Integrated Chinese and Western Medicine and Wuhan Hospital of Traditional Chinese Medicine from February 1 to March 1, 2020, were included.All patients were treated with XFBD based on conventional therapies.Clinical outcomes, length of hospital stay, and lung CT images of patients were observed.Laboratory indicators were compared between admission and the 14 th day of treatment.Traditional Chinese medicine(TCM) symptoms and signs on the 7 th and 14 th days of treatment were also compared with baseline.The differences in clinical characteristics and clinical outcomes between XFBD and western medicine or conventional therapies were analyzed with the published trials on severe COVID-19 cases during the same period as external controls.According to the results, among the 41 cases, 40 were cured and discharged, and 1 died; the median length of hospital stay was 22 days, and the improvement rate of lung CT was 87.2%(34/39).Compared with the conditions on admission, the levels of white blood cells(WBC), C-reactive protein(CRP), fibrinogen(FIB), and lactate dehydrogenase(LDH) were reduced(P<0.05, P<0.01), and levels of procalcitonin(PCT), prothrombin time(PT), creatine kinase(CK), alanine aminotransferase(AST), total bilirubin(TBiL), and other indicators showed a downward trend.Moreover, symptoms like fever, cough, chest tightness/shortness of breath, dyspnea, head and body pain, anorexia, and greasy tongue coating were significantly improved on the 7 th and 14 th days of treatment(P<0.05, P<0.01), and fatigue was improved on the 14 th day of treatment(P<0.01).The mortality, adverse reactions, and major events of the XFBD group were significantly lower than those of the western medicine and conventional treatment groups in the same period, and the usage of antibiotics, hormones, vasopressin, and invasive mechanical ventilation during treatment were generally less than other groups.In conclusion, XFBD has good efficacy and safety in the treatment of severe COVID-19 cases by improving inflammation and clinical symptoms, promoting the absorption of lung inflammation, and reducing mortality.
