Should we continue breastfeeding after SARS-CoV-2 infection or mRNA vaccination?

The coronavirus disease 2019(COVID-19),which is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),has posed a potential threat to infant health.The World Health Organization recommended that the benefits of breastfeeding far outweigh the potential risk of transmission,but there is no denying that the current evidence is insufficient.Moreover,although the COVID-19 mRNA vaccine has played an effective role in protection against infection,individuals have increasing concerns about the safety of breastfeeding after vaccination,and which have caused some breastfeeding women to postpone vaccination or stop breastfeeding early.Thus,in this review,we provide an in-depth discussion of whether SARS-CoV-2 and the vaccine will affect babies through breast milk.On one hand,only a very small number of milk samples were identified positive for viral RNA and almost impossible to be live virus particles.The milk of most lactating women after vaccination did not contain vaccine-related mRNA and polyethylene glycol.On the other hand,the antibodies and biologically active molecules like lactoferrin are abundant in the milk of lactating women who have been infected or vaccinated,which can provide potential protection against infants’respiratory and gastrointestinal infections.Therefore,in terms of implications for clinical practice,the results of our study support that lactating women who have been infected or vaccinated should be encouraged to breastfeed their infants under the premise of taking appropriate sanitary measures.

Alignment of inertialess spheroidal particles in flow-structure-dominated regions of turbulent channel flow:shape effect

The alignment of elongated fibers and thin disks is known to be significantly influenced by the presence of fluid coherent structures in near-wall turbulence(Cui et al.2021).However,this earlier study is confined to the spheroids with infinitely large or small aspect ratio,and the shape effect of finite aspect ratio on the alignment is not considered.The current study investigates the shape-dependent alignment of inertialess spheroids in structure-dominated regions of channel flow.With utilizing an ensemble-averaged approach for identifying the structure-dominated regions,we analyze the eigensystem of the linear term matrix in the Jeffery equation,which is governed by both particle shape and local fluid velocity gradients.In contrast to earlier conventional analysis based on local vorticity and strain rate,our findings demonstrate that the eigensystem of the Jeffery equation offers a convenient,effective,and universal framework for predicting the alignment behavior of inertialess spheroids in turbulent flows.By leveraging the eigensystem of the Jeffery equation,we uncover a diverse effect of fluid coherent structures on spheroid alignment with different particle shapes.Furthermore,we provide explanations for both shape-independent alignments observed in vortical-core regions and shape-dependent alignments around near-wall streamwise vortices.

Bifunctional Activated Carbon Ultrathin Fibers:Combining the Removal of VOCs and PM in One Material

Volatile organic compounds(VOCs)and particulate matter(PM)are both frequently present in air as contaminants,posing serious health and environmental hazards.The current filtration of VOCs utilizes entirely different materials compared with PM filtration,adding complexity to air cleaning system.Herein,we design a pitch-based activated carbon ultrathin fibers(PACUFs)for bifunctional air purification.The PACUFs,with fiber diameter of∼1.2μm and specific surface area of 2341 m^(2) g^(−1),provide both high VOCs adsorption capacity(∼706 mg g^(−1))and excellent efficiency of∼97% PM_(0.3) filtration with low pressure drop.In contrast,traditional activated carbon fibers exhibit VOCs adsorption capacity of∼448 mg g^(−1) and PM_(0.3) removal efficiency of only∼36%at an equal area density of∼190 g m^(−2).Theoretical investigations reveal the filtration mechanism of the high-performance bifunctional fibrous PACUFs,considering full advantages of the high surface area,small pore size,and significant micropore volume.