ABSTRACT
Developing a high-performance membrane electrode assembly (MEA) poses a formidable challenge for fuel cells, which lies in achieving both high metal loading and efficient catalytic activity concurrently for MEA catalysts. Here, we introduce a porous Co@NC carrier to synthesize sub-4 nm PtCo intermetallic nanocrystals, achieving an impressive Pt loading of 27 wt %. The PtCo-CoNC catalyst demonstrates exceptional catalytic activity and remarkable stability for the oxygen reduction reaction. Advanced characterization techniques and theoretical calculations emphasize the synergistic effect between PtCo alloys and single Co atoms, which enhances the desorption of the OH* intermediate. Furthermore, the PtCo-CoNC-based cathode delivers a high power density of 1.22 W cm-2 in the MEA test owing to the enhanced mass transport, which is verified by the simulation results of the O2 distributions and current density inside the catalyst layer. This study lays the groundwork for the design of efficient catalysts with practical applications in fuel cells.
ABSTRACT
BACKGROUND: It has been proven that lung cancer in the youth exhibited rapid progression, thus timely and accurate diagnosis is crucial. The aim of this study is to explore the clinicopathological characteristics of lung cancer in the youth, so as to provide clues for diagnosis. METHODS: The study enrolled patients aged younger than 40 years with lung cancer diagnosed with histology or cytology in our hospital between 1995-2012. We retrospectively analyzed sex, age, symptoms, smoking history, histology, stage and misdiagnosis. RESULTS: One hundred and thirty patients with lung cancer in the youth were enrolled, which comprise 5.2% of all cases of lung cancer in that period. Among them, 68.5% were male; 53.8% were aged between 36 and 40 years. Common symptoms included cough and hemoptysis, and systematic symptoms were relatively uncommon; and 11.8% showed no symptoms. 63.3% had a smoking history, and the time between initial symptom and final diagnosis averaged 3.9 months. The misdiagnosis rate was 51.5%, with tuberculosis as the leading misdiagnosis. 85.4% were staged III/IV. Primary lesion often located in upper lobes. Adenocarcinoma was the commonest histology, and 72.3% of the whole group was poorly differentiated. CONCLUSIONS: Lung cancer in the youth showed some special clinicopathological characteristics. Doctors should consider the possibility of lung cancer in patients with seemly diagnosis of tuberculosis, especially in those without symptomatic symptoms, and perform histological or cytological examinations. The absence of smoking history cannot rule out the possibility of lung cancer in youth patients.
