Direct visualizations of air flow in the human upper airway using in-vitro models

A better understanding of airflow characteristics in the upper airway(UA) is crucial in investigating obstructive sleep apnea(OSA), particle sedimentation, drug delivery, and many biomedical problems. Direct visualization of air flow patterns in in-vitro models with realistic anatomical structures is a big challenge. In this study, we constructed unique half-side transparent physical models of normal UA based on realistic anatomical structures. A smoke-wire method was developed to visualize the air flow in UA models directly. The results revealed that the airflow through the pharynx was laminar but not turbulent under normal inspiration, which suggested that compared with turbulent models, a laminar model should be more suitable in numerical simulations. The flow predicted numerically using the laminar model was consistent with the observations in the physical models. The comparison of the velocity fields predicted numerically using the half-side and complete models confirmed that it was reasonable to investigate the flow behaviors in UA using the half-side model. Using the laminar model, we simulated the flow and evaluated the effects of UA narrowing caused by rostral fluid shift on pharyngeal resistance. The results suggested that fluid shift could play an important role in the formation of hypopnea or OSA during sleep.

Genomes of 12 fig wasps provide insights into the adaptation of pollinators to fig syconia

Figs and fig pollinators are one of the few classic textbook examples of obligate pollination mutualism.The specific dependence of fig pollinators on the relatively safe living environment with sufficient food sources in the enclosed fig syconia implies that they are vulnerable to habitat changes.However,there is still no extensive genomic evidence to reveal the evolutionary footprint of this long-term mutually beneficial symbiosis in fig pollinators.In fig syconia,there are also non-pollinator species.The non-pollinator species differ in their evolutionary and life histories from pollinators.We conducted comparative analyses on 11 newly sequenced fig wasp genomes and one previously published genome.The pollinators colonized the figs approximately 66.9 million years ago,consistent with the origin of host figs.Compared with nonpollinators,many more genes in pollinators were subject to relaxed selection.Seven genes were absent in pollinators in response to environmental stress and immune activation.Pollinators had more streamlined gene repertoires in the innate immune system,chemosensory toolbox,and detoxification system.Our results provide genomic evidence for the differentiation between pollinators and nonpollinators.The data suggest that owing to the long-term adaptation to the fig,some genes related to functions no longer required are absent in pollinators.