A general route via formamide condensation to prepare atomically dispersed metal-nitrogen-carbon electrocatalysts for energy technologies

Single-atom electrocatalysts (SAECs) have gained tremendous attention due to their unique active sites and strong metal–substrate interactions. However, the current synthesis of SAECs mostly relies on costly precursors and rigid synthetic conditions and often results in very low content of single-site metal atoms. Herein, we report an efficient synthesis method to prepare metal–nitrogen–carbon SAECs based on formamide condensation and carbonization, featuring a cost-effective general methodology for the mass production of SAECs with high loading of atomically dispersed metal sites. The products with metal inclusion were termed as formamide-converted metal–nitrogen–carbon (shortened as f-MNC) materials. Seven types of single-metallic f-MNC (Fe, Co, Ni, Mn, Zn, Mo and Ir), two bi-metallic (ZnFe and ZnCo) and one tri-metallic (ZnFeCo) SAECs were synthesized to demonstrate the generality of the methodology developed. Remarkably, these f-MNC SAECs can be coated onto various supports with an ultrathin layer as pyrolysis-free electrocatalysts, among which the carbon nanotube-supported f-FeNC and f-NiNC SAECs showed high performance for the O2 reduction reaction (ORR) and the CO2 reduction reaction (CO2RR), respectively. Furthermore, the pyrolysis products of supported f-MNC can still render isolated metallic sites with excellent activity, as exemplified by the bi-metallic f-FeCoNC SAEC, which exhibited outstanding ORR performance in both alkaline and acid electrolytes by delivering ∼70 and ∼20 mV higher half-wave potentials than that of commercial 20 wt% Pt/C, respectively. This work offers a feasible approach to design and manufacture SAECs with tuneable atomic metal components and high density of single-site metal loading, and thus may accelerate the deployment of SAECs for various energy technology applications

DataSheet_1_MRI VS. FDG-PET for diagnosis of response to neoadjuvant therapy in patients with locally advanced rectal cancer.docx

AimIn this study, we aimed to compare the diagnostic values of MRI and FDG-PET for the prediction of the response to neoadjuvant chemoradiotherapy (NACT) of patients with locally advanced Rectal cancer (RC).MethodsElectronic databases, including PubMed, Embase, and the Cochrane library, were systematically searched through December 2021 for studies that investigated the diagnostic value of MRI and FDG-PET in the prediction of the response of patients with locally advanced RC to NACT. The quality of the included studies was assessed using QUADAS. The pooled sensitivity, specificity, positive and negative likelihood ratio (PLR and NLR), and the area under the ROC (AUC) of MRI and FDG-PET were calculated using a bivariate generalized linear mixed model, random-effects model, and hierarchical regression.ResultsA total number of 74 studies with recruited 4,105 locally advanced RC patients were included in this analysis. The pooled sensitivity, specificity, PLR, NLR, and AUC for MRI were 0.83 (95% CI: 0.77–0.88), 0.85 (95% CI: 0.79–0.89), 5.50 (95% CI: 4.11-7.35), 0.20 (95% CI: 0.14–0.27), and 0.91 (95% CI: 0.88–0.93), respectively. The summary sensitivity, specificity, PLR, NLR and AUC for FDG-PET were 0.81 (95% CI: 0.77-0.85), 0.75 (95% CI: 0.70–0.80), 3.29 (95% CI: 2.64–4.10), 0.25 (95% CI: 0.20–0.31), and 0.85 (95% CI: 0.82–0.88), respectively. Moreover, there were no significant differences between MRI and FDG-PET in sensitivity (P = 0.565), and NLR (P = 0.268), while the specificity (P = 0.006), PLR (P = 0.006), and AUC (P = 0.003) of MRI was higher than FDG-PET.ConclusionsMRI might superior than FGD-PET for the prediction of the response of patients with locally advanced RC to NACT.</p

Phase diagram of the aggregates according to incubation time.

<p>Phase diagram of the aggregates according to incubation time.</p

Correlations among Scales of the CERQ-Ck and the CDI-C.

<p>Correlations among Scales of the CERQ-Ck and the CDI-C.</p

Infrared spectra of the amide I band with curve fitting before and after aggregation.

<p>a) WPI. b) WPH. C) Aggregates.</p

Curve-fitting results.

<p>Curve-fitting results.</p

t (%) value of aggregates obtained at different incubation times.

<p>t (%) value of aggregates obtained at different incubation times.</p

Infrared spectra of the proteins, 400–4000 cm⁻¹.

<p>a) WPI. b) WPH. c) Aggregates. The system was continuously purged with N₂.</p

Amino acid composition of WPH and aggregates (incubated for 0.5 or 12 h).

<p>Amino acid composition of WPH and aggregates (incubated for 0.5 or 12 h).</p

Intrinsic fluorescence spectra of aggregates according to incubation time.

<p>Intrinsic fluorescence spectra of aggregates according to incubation time.</p