The oxygen reduction reaction (ORR) is one of the crucial reactions in fuel cells and metal-air batteries.Heteroatom doped carbon spheres can serve as alternative low-cost non-metal electrocatalysts for ORR. Herein, we developed an effective route to the synthesis of uniform and electrochemically active B-doped hollow carbon nanospheres (BHCSs). BHCSs were synthesized via the carbonization of a boric phenolic resin supported by SiO 2 , followed by etching the SiO 2 template. The content of B, B dopant species and specific surface area were adjusted by changing the content of the B precursor and the calcination temperature. Moreover, their influence on the performance of electrocatalytic activity was explored. It was found that, among these B-doping type materials (BC 2 O, BCO 2 , B 4 C and BC 3 ), B-C bonds (B 4 C and BC 3 ) played a crucial role on improving the electrocatalytic activity. Compared with the hollow carbon nanospheres (HCSs), a 70 mV positive shift of the onset potential and 1.7 times kinetic current density could be clearly observed with BHCSs. In addition, the BHCSs revealed better stability and methanol tolerance than commercial Pt/C (HiSPEC™ 3000, 20%). Thus, the as-prepared BHCSs, as inexpensive and efficient non-metal ORR catalysts, may have a promising application in direct methanol fuel cells.
The recognition of adiposity as a risk factor for gastric cancer is mainly based on traditional anthropometric indices, such as body mass index, which are unable to discriminate between lean and fat mass. We undertook this study to examine body composition and subsequent risk of gastric cancer. This is a prospective analysis of participants free of cancer from the UK Biobank. We measured baseline body composition with electrical bioimpedance analysis and confirmed cancer diagnosis through linkage to cancer and death registries. We evaluated hazard ratios (HRs) and confidence interval (CIs) with COX models adjusting for potential confounders. We documented 326 cases of cancer from 474,929 participants over a median follow‐up of 6.6 years. Both male (HR 1.70, 95% CI 1.01 to 2.89) and female participants (HR 2.47, 95% CI 1.15 to 5.32) in the highest quartile of whole body fat‐free mass were associated with increased risk of gastric cancer as compared with those in the lowest quartile.Whole body fat mass was associated with a decreased risk of gastric cancer (HR per 5‐unit increase 0.86, 95% CI 0.74 to 0.99) in females, but not in males. We concluded that fat‐free mass and fat mass may have different effects on gastric cancer risk. This study provided evidence for individualized weight management for the prevention of gastric cancer.
The synthesis of nitrogen-doped hierarchical porous carbon materials for high performance supercapacitors through carbonization of PoPD by using molten-salt as a template.
Objective
To evaluate the association between body composition and subsequent risk of the major gynecologic malignancies.
Methods
This is a prospective analysis of participants from the UK Biobank. We measured baseline body composition and confirmed cancer diagnosis through linkage to cancer and death registries. We evaluated hazard ratios (HRs) and confidence interval (CIs) with COX models adjusting for potential confounders.
Results
We document 1430 cases of the top three gynecologic malignancies (uterine corpus cancer 847 cases, ovarian cancer 514 cases, and cervical cancer 69 cases) from 245,084 female participants (75,307 were premenopausal and 169,777 were postmenopausal). For premenopausal women, whole body fat‐free mass (WBFFM) was associated with an increased risk of uterine corpus cancer (Adjusted HR per unit increase 1.04, 95% CI 1.02–1.06). For postmenopausal women, compared with the first quartile, the fourth quartile of WBFFM and whole body fat mass(WBFM) was associated with 2.16 (95% CI 1.49–3.13) times and 1.89 (95% CI 1.31–2.72) times of increased uterine corpus cancer risk, respectively. Regarding the distribution of body fat mass (FM)/fat‐free mass (FFM), FFM distributed in the trunk was associate with increased uterine corpus cancer risk in premenopausal (HR 1.18,95% CI 1.07–1.31) and postmenopausal women (HR 1.13,95% CI 1.09–1.18). Meanwhile, FM/FFM distributed in the limbs present an U‐shaped associations with uterine corpus cancer risk. We did not observe any association between aforementioned body composition indices with ovarian or cervical cancer.
Conclusion
FM is associated with an increased risk of uterine corpus cancer in postmenopausal women. Meanwhile, FFM is found to be a risk factor for uterine corpus cancer in both premenopausal and postmenopausal women. No association of body composition with ovarian or cervical cancer was observed.
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