High-loading Pt-alloy catalysts for boosted oxygen reduction reaction performance

To improve performance of membrane electrode assembly(MEA)at large current density region,efficient mass transfer at the cathode is desired,for which a feasible strategy is to lower catalyst layer thickness by constructing high loading Pt-alloy catalysts on carbon.But the high loading may induce unwanted par-ticle aggregation.In this work,H-PtNi/C with 33%(mass)Pt loading on carbon and monodisperse distri-bution of 3.55 nm PtNi nanoparticles,was prepared by a bimodal-pore route.In electrocatalytic oxygen reduction reaction(ORR),H-PtNi/C displays an activity inferior to the low Pt loading catalyst L-PtNi/C(13.3%(mass))in the half-cell.While in H_(2)-0_(2) MEA,H-PtNi/C delivers the peak power density of 1.51 W·cm^(-2) and the mass transfer limiting current density of 4.4 A·cm^(-2),being 21%and 16%higher than those of L-PtNi/C(1.25 W·cm^(-2),3.8 A·cm^(-2))respectively,which can be ascribed to enhanced mass trans-fer brought by the thinner catalyst layer in the former.In addition,the same method can be used to pre-pare PtFe alloy catalyst with a high-Pt loading of 36%(mass).This work may lead to a range of catalyst materials for the large current density applications,such as fuel cell vehicles.

Increasing stiffness promotes pulmonary retention of ligand-directed dexamethasone-loaded nanoparticle for enhanced acute lung inflammation therapy

Inhaled nanoparticles(NPs)need to penetrate the bronchial mucosa to deliver drug payloads deeply in the lung for amplified local therapy.However,the bronchial mucociliary barrier eliminates NPs rapidly,which considerably limits their mucosal penetration.In this study,we find that surface ligand modification and stiffness adjustment of NPs contribute to the significantly enhanced bronchial mucosal absorption and pulmonary retention of inhaled drugs.We utilize neonatal Fc receptor ligand(FcBP)to modify the rationally designed low stiffness NPs(Soft-NP)and high stiffness NPs(Stiff-NP)to target bronchial mucosa.In an acute lung inflammation rat model,after intranasal administration with dexamethasone-loaded NPs,Stiff-NP endowed with FcBP displays superior therapeutic effects.The in vitro data demonstrate that the promotion effect of FcBP to bronchial mucosal absorption of Stiff-NP dominates over Soft-NP.This could be attributed to the higher affinity between ligand-receptor when incorporating FcBP on the Stiff-NP surface.Meanwhile,high stiffness modulates more actin filaments aggregation to mediate endocytosis,along with strengthened Ca2+signal to enhance exocytosis.Conclusively,we highlight that FcBP-modified NPs with higher stiffness would be a potential pulmonary drug delivery system.

Changing Patterns in Digestive Diseases Mortality in Urban and Rural Areas—China,1987-2021

What is already known about this topic?Digestive diseases(DDs)are a global health concern with a substantial epidemiological and economic impact,given their high prevalence.What is added by this report?This study investigated the trends in mortality related to DDs in China from 1987 to 2021,focusing on the urban-rural divide.Additionally,it aimed to determine the specific impacts of age,period,and cohort on DDs mortality.What are the implications for public health practice?There is a need to prioritize and allocate more resources toward the future management of DDs in order to effectively address the challenges posed by urbanization and aging populations.