Ultrafast water harvesting and transport in hierarchical microchannels.

Various natural materials have hierarchical microscale and nanoscale structures that allow for directional water transport. Here we report an ultrafast water transport process in the surface of a Sarracenia trichome, whose transport velocity is about three orders of magnitude faster than those measured in cactus spine and spider silk. The high velocity of water transport is attributed to the unique hierarchical microchannel organization of the trichome. Two types of ribs with different height regularly distribute around the trichome cone, where two neighbouring high ribs form a large channel that contains 1-5 low ribs that define smaller base channels. This results in two successive but distinct modes of water transport. Initially, a rapid thin film of water is formed inside the base channels (Mode I), which is followed by ultrafast water sliding on top of that thin film (Mode II). This two-step ultrafast water transport mechanism is modelled and experimentally tested in bio-inspired microchannels, which demonstrates the potential of this hierarchal design for microfluidic applications.

High-Efficient Microdroplet Harvesting and Detaching Inspired from Sarracenia Lid Trichome.

Fog harvesting plays a pivotal role in harnessing atmospheric water resources and holds significant promise for alleviating global water scarcity. Nonetheless, enhancing harvesting efficiency remains a persistent challenge, especially concerning the rapid detachment of droplets from surfaces. In this study, we discovered that the trichomes of Sarracenia not only efficiently harvest and transport liquid but also quickly drain harvested liquid. We have elucidated the augmentation mechanism behind effective fog harvesting and drainage within the lid of Sarracenia. The trichomes facing the counterflow can enhance fog harvesting efficiency by 80% through air-flow-assisted spreading of liquid film. The wedge corner generated by the interface between hydrophilic and hydrophobic surfaces, coupled with the reduction of cross-sectional angles, diminishes the adhesive force of liquid droplets, fosters droplet spheroidization, and substantially facilitates droplet detachment. In addition, the quantitative detachment of droplets can be achieved by adjusting the cross-sectional angle and wetting gradient. This integrated structure combining efficient condensation and detachment has diverse applications in cooling towers and seawater desalination.

High-Efficient Fog Harvest from a Synergistic Effect of Coupling Hierarchical Structures.

Fog harvesting is an important method to solve the water shortage in arid and semi-arid areas by collecting water from air. Improving fog harvesting efficiency is still a big challenge to be overcome. Herein, under the inspiration of natural creatures, a novel harvesting structure that couples a hierarchical microchannel (HMC) needle with the Janus membrane by taking a conical pore as their junction is proposed. Such an HMC-conical pore-Janus membrane system can improve the harvesting efficiency by regulation of liquid behavior in the whole fog harvesting process involving droplet capture from air, high speed transport on the microchannel, and droplet detachment from Janus. The synergistic effects of the hierarchical channel-conical pore-Janus structure are exploited in terms of capture, transport, and detachment capabilities, and their underlying mechanism to enhance fog harvesting efficiency is built. Compared with the traditional harvesting structure, the proposed hierarchical channel-conical-Janus coupling mode was demonstrated to improve fog harvesting efficiency by 90%. Such a coupled system has potential applications in efficient fog harvesting systems, microfluidic devices, and liquid manipulation.

Highly Efficient Multiscale Fog Collector Inspired by Sarracenia Trichome Hierarchical Structure.

Fog harvesting through bionic strategies to solve water shortage has drawn considerable attention. Recently, an ultrafast fog harvesting and transport mode was identified in Sarracenia trichome, which is mainly attributed to its superslippery capillary force induced by its unique hierarchical microchannel. However, the underlying effect of hierarchical microchannel-induced ultrafast transport on fog harvesting and the multiscale structural coupling effect on highly efficient fog harvesting are still great challenges. Herein, a bionic Sarracenia trichome (BST) with an on-demand regular hierarchical microchannel is designed using a one-step thermoplastic stretching approach on a glass fiber bundle. The BST is engineered to harbor major channels confined by an inner gear pattern along with junior microchannels that are automatically assembled by the glass fiber monofilaments. The BST shows enhanced capillary condensation and fog harvesting performance, in part due to its coupling effect with a Janus membrane (JM). Hence, a highly efficient multiscale fog collector is developed, in which a gradient high-pressure field is purposely formed to improve by threefold fog harvesting performance compared with a single-scale structure. This easy manufacturing and low-cost fog collector may represent a useful tool for harvesting fog water for production and living and pave the way for further investigations.

Preference for daily versus on-demand pre-exposure prophylaxis for HIV and correlates among men who have sex with men: the China Real-world Oral PrEP Demonstration study.

INTRODUCTION: This study explores the preference for daily versus on-demand pre-exposure prophylaxis (PrEP) among men who have sex with men (MSM) in developing countries when both regimens are available. METHODS: From 11 December 2018 to 19 October 2019, we recruited MSM for an open-label real-world PrEP demonstration study in four major cities in China. Subjects selected their preferred PrEP (oral tenofovir/emtricitabine) regimen (daily vs. on-demand) at recruitment and underwent on-site screening before initiation of PrEP. We used logistic regression to assess preference for daily PrEP and correlates. RESULTS: Of 1933 recruited MSM, the median age was 29 years, 7.6% was currently married to or living with a female; the median number of male sexual partners was four and 6.1% had used post-exposure prophylaxis (PEP) in the previous six months. HIV infection risk was subjectively determined as very high (>75%) in 7.0% of subjects, high (50% to 75%) in 13.3%, moderate (25% to 49%) in 31.5% and low or none (0% to 24%) in 48.1%. On average, participants preferred on-demand PrEP over daily PrEP (1104 (57.1%) versus 829 (42.9%)) at recruitment. In multivariable analysis, currently being married to or living with a female was associated with 14.6 percentage points lower preference for daily PrEP (marginal effect = -0.146 [95% CI: -0.230, -0.062], p = 0.001); whereas the number of male sexual partners (marginal effect = 0.003 [95% CI: 0.000, 0.005], p = 0.034) and a subjective assessment of being very high risk of HIV infection (vs. low and no risk, marginal effect size = 0.105 [95% CI: 0.012, 0.198], p = 0.027) were associated with increased preference for daily versus on-demand PrEP. Among the 1933 potential participants, 721 (37.3%) did not attend the subsequent on-site screening. Lower-income, lower education level, lower subjective expected risk of HIV infection risk and younger age positively correlated with the absence of on-site screening. CONCLUSIONS: MSM in China prefer both daily and on-demand PrEP when both regimens are provided free. Social structural factors and subjective risk of HIV infection have significant impacts on PrEP preference and use. The upcoming national PrEP guideline should consider incorporating both regimens and the correlates to help implement PrEP in China.

Positive effects of Xuebijing injection on intestinal microbiota and metabolite spectrum in septic rats / 中华危重病急救医学

OBJECTIVE@#To explore the effect of Xuebijing injection on inflammation in sepsis by regulating intestinal microbiota and its metabolites.@*METHODS@#A total of 45 male Sprague-Dawley (SD) rats were randomly divided into Sham operation group (Sham group), cecal ligation and perforation (CLP) induced sepsis group (CLP group), and Xuebijing intervention group (XBJ group, 4 mL/kg Xuebijing injection was injected intraperitoneally at 1 hour after CLP), with 15 rats in each group. The survival of rats was observed at 24 hours after operation and sacrificed. Feces were collected for 16S rRNA gene sequencing and liquid chromatography-mass spectrometry (LC-MS) analysis.@*RESULTS@#At 24 hours after operation, all rats in the Sham group survived, the mortality of rats in the XBJ group was lower than that in the CLP group [47% (7/15) vs. 60% (9/15), P > 0.05]. Compared with the Sham group, the diversity of gut microbiota in the CLP group decreased, the dominant flora changed, and the abundance of inflammation-related flora increased. Xuebijing improved the changes in gut microbiota caused by sepsis, and α diversity showed an increasing trend (Ace index: 406.0±22.5 vs. 363.2±38.2, Chao1 index: 409.7±21.8 vs. 362.4±42.5, both P > 0.05). Restrictive constrained principal coordinate analysis (cPCoA) showed a high similarity in gut microbiota among the same group of rats. The CLP group was dominated by Bacteroidetes, while the Sham and XBJ groups were dominated by Firmicutes. In addition, compared with the CLP group, Xuebijing treatment increased the abundance of beneficial bacteria in septic rats, such as Verrucomicrobia, Akkermansia and Lactobacillus. LC-MS and orthogonal partial least squares discriminant analysis (OPLS-DA) showed that there were 12 main differential metabolites among the three groups, and there were certain correlations between these metabolites, which were related to amino acid and lipid metabolism. Correlation analysis showed a significant correlation between changes in metabolites and microbial communities.@*CONCLUSIONS@#Xuebijing can improve the survival rate of septic rats, regulate the composition of intestinal flora and related metabolites, which provides a new pathophysiological mechanism for Xuebijing in the treatment of sepsis.

Progress of effects of light on plant flavonoids / 中国中药杂志

As an important secondary metabolites of medicinal plant, flavonoids plays a very important role on itself including light protection and antioxidant. Light is one of the important environmental factors which impacts the secondary metabolites of plant and has a significant impact on biological synthesis of flavonoids. This paper reviews the recent progress of the effects of light on flavonoids on the plants focusing from light intensity and light quality, and summarizes briefly functions of the phenylalanine ammonia lyase (PAL) in plant secondary metabolism and the upstream key enzyme chalcone synthase (CHS) in flavonoid biosynthetic pathway.