High‐entropy materials, a new class of alloys that incorporate five or more principal elements into single‐phase crystal structures, have received considerable interest in materials science and ...engineering. Considering the tailored composition and disordered configuration, these high‐entropy materials may arouse functional synergism towards electrocatalysis. Here, a new strategy for preparing high‐entropy metal phosphides (HEMPs) was developed by a eutectic solvent method. The as‐prepared HEMP possessed a single metal phosphide phase with up to five homogenously distributed metal components. The versatile application of high‐entropy materials was highlighted by integrating the HEMP catalyst into a two‐electrode configuration for electrocatalytic water splitting.
HEMP‐catalyzed water splitting: A new synthetic approach to high‐entropy metal phosphides (HEMP) based on a eutectic solvent method is presented. After a one‐step in situ phosphorization reaction, the HEMP nanosheets are successfully fabricated. The versatile application of the high‐entropy material is highlighted by integrating the HEMP catalyst into a two‐electrode configuration for electrocatalytic water splitting.
Significant advances in materials, microscale technology, and stem cell biology have enabled the construction of 3D tissues and organs, which will ultimately lead to more effective diagnostics and ...therapy. Organoids and organs‐on‐a‐chip (OOC), evolved from developmental biology and bioengineering principles, have emerged as major technological breakthrough and distinct model systems to revolutionize biomedical research and drug discovery by recapitulating the key structural and functional complexity of human organs in vitro. There is growing interest in the development of functional biomaterials, especially hydrogels, for utilization in these promising systems to build more physiologically relevant 3D tissues with defined properties. The remarkable properties of defined hydrogels as proper extracellular matrix that can instruct cellular behaviors are presented. The recent trend where functional hydrogels are integrated into organoids and OOC systems for the construction of 3D tissue models is highlighted. Future opportunities and perspectives in the development of advanced hydrogels toward accelerating organoids and OOC research in biomedical applications are also discussed.
Organoids and organs‐on‐a‐chip have emerged as a major technological breakthrough as model systems to revolutionize biomedical research by recapitulating the structural and functional complexity of human organs. There is growing interest in the utilization of well‐defined hydrogels in these two systems to improve the physiological relevance of 3D models.
Airborne bacteria have gained increasing attention because they affect ecological balance and pose potential risks on human health. Recently, some studies have focused on the abundance and ...composition of airborne bacteria under heavy, hazy polluted weather in China, but they reached different conclusions about the comparisons with non-polluted days. In this study, we tested the hypothesis that meteorological factors could have a higher impact on shaping airborne bacterial communities than air pollutants by systematically monitoring the communities for 1year. Total suspended particles in Beijing were sampled for 20 consecutive days in each season of 2015. Bacterial abundance varied from 8.71×103 to 2.14×107 ribosomal operons per cubic meter according to the quantitative PCR analysis. There were relatively higher bacterial counts in spring and in autumn than in winter and summer. Airborne bacterial communities displayed a strong seasonality, according to the hierarchical cluster analysis. Only two exceptions overtook the seasonal trend, and both occurred in or after violent meteorological changes (sandstorm or rain). Aggregated boosted tree analysis performed on bacterial abundance showed that the dominant factors shaping bacterial communities were meteorological. They were air pressure in winter, air temperature and relative humidity in spring, RH in summer, and vapor pressure in autumn. Variation partition analysis on community structure showed that meteorological factors explained more variations than air pollutants. Therefore, both of the two models verified our hypothesis that the differences in airborne bacterial communities in polluted days or non-polluted days were mainly driven by the discrepancies of meteorological factors rather than by the presence of air pollutants.
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•The airborne bacteria concentrations and community structure showed strong seasonality.•However, violent weather events broke seasonal trends of bacteria community.•Within season, meteorological factors explained more variations in bacteria community structure than air pollution.
Abstract
Androgen is essential for male development and cortisol is involved in reproduction in fishes. However, the in vivo roles of cortisol and specific androgens such as 11-ketotestosterone ...(11-KT) in reproductive development need to be described with genetic models. Zebrafish cyp11c1 encodes 11β-hydroxylase, which is essential for the biosynthesis of 11-KT and cortisol. In this study, we generated a zebrafish mutant of cyp11c1 (cyp11c1-/-) and utilized it to clarify the roles of 11-KT and cortisol in sexual development and reproduction. The cyp11c1-/- fish had smaller genital papilla and exhibited defective natural mating but possessed mature gametes and were found at a sex ratio comparable to the wildtype control. The cyp11c1-/- males showed delayed and prolonged juvenile ovary-to-testis transition and displayed defective spermatogenesis at adult stage, which could be rescued by treatment with 11-ketoandrostenedione (11-KA) at certain stages. Specifically, during testis development of cyp11c1-/- males, the expression of insl3, cyp17a1, and amh was significantly decreased, suggesting that 11-KT is essential for the development and function of Leydig cells and Sertoli cells. Further, spermatogenesis-related dmrt1 was subsequently downregulated, leading to insufficient spermatogenesis. The cyp11c1-/- females showed a reduction in egg spawning and a failure of in vitro germinal vesicle breakdown, which could be partially rescued by cortisol treatment. Taken together, our study reveals that zebrafish Cyp11c1 is not required for definite sex differentiation but is essential for juvenile ovary-to-testis transition, Leydig cell development, and spermatogenesis in males through 11-KT, and it is also involved in oocyte maturation and ovulation in females through cortisol.
COVID-19, caused by SARS-CoV-2, is an acute and rapidly developing pandemic, which leads to a global health crisis. SARS-CoV-2 primarily attacks human alveoli and causes severe lung infection and ...damage. To better understand the molecular basis of this disease, we sought to characterize the responses of alveolar epithelium and its adjacent microvascular endothelium to viral infection under a co-culture system. SARS-CoV-2 infection caused massive virus replication and dramatic organelles remodeling in alveolar epithelial cells, alone. While, viral infection affected endothelial cells in an indirect manner, which was mediated by infected alveolar epithelium. Proteomics analysis and TEM examinations showed viral infection caused global proteomic modulations and marked ultrastructural changes in both epithelial cells and endothelial cells under the co-culture system. In particular, viral infection elicited global protein changes and structural reorganizations across many sub-cellular compartments in epithelial cells. Among the affected organelles, mitochondrion seems to be a primary target organelle. Besides, according to EM and proteomic results, we identified Daurisoline, a potent autophagy inhibitor, could inhibit virus replication effectively in host cells. Collectively, our study revealed an unrecognized cross-talk between epithelium and endothelium, which contributed to alveolar-capillary injury during SARS-CoV-2 infection. These new findings will expand our understanding of COVID-19 and may also be helpful for targeted drug development.
Abstract
Motivation
MEDLINE is the primary bibliographic database maintained by National Library of Medicine (NLM). MEDLINE citations are indexed with Medical Subject Headings (MeSH), which is a ...controlled vocabulary curated by the NLM experts. This greatly facilitates the applications of biomedical research and knowledge discovery. Currently, MeSH indexing is manually performed by human experts. To reduce the time and monetary cost associated with manual annotation, many automatic MeSH indexing systems have been proposed to assist manual annotation, including DeepMeSH and NLM’s official model Medical Text Indexer (MTI). However, the existing models usually rely on the intermediate results of other models and suffer from efficiency issues. We propose an end-to-end framework, MeSHProbeNet (formerly named as xgx), which utilizes deep learning and self-attentive MeSH probes to index MeSH terms. Each MeSH probe enables the model to extract one specific aspect of biomedical knowledge from an input article, thus comprehensive biomedical information can be extracted with different MeSH probes and interpretability can be achieved at word level. MeSH terms are finally recommended with a unified classifier, making MeSHProbeNet both time efficient and space efficient.
Results
MeSHProbeNet won the first place in the latest batch of Task A in the 2018 BioASQ challenge. The result on the last test set of the challenge is reported in this paper. Compared with other state-of-the-art models, such as MTI and DeepMeSH, MeSHProbeNet achieves the highest scores in all the F-measures, including Example Based F-Measure, Macro F-Measure, Micro F-Measure, Hierarchical F-Measure and Lowest Common Ancestor F-measure. We also intuitively show how MeSHProbeNet is able to extract comprehensive biomedical knowledge from an input article.
The search of multifunctional epoxy nanocomposites with both strength and toughness combined with smart features such as electrical conductivity is essential in design of advanced materials. In this ...work, by utilizing a binary nanofiller strategy, both strength and toughness as well as high electrical conductivity are obtained in epoxy with trace nanopolystyrene grafted with epichlorohydrin (nano g-PS) to facilitate the dispersion of multi-walled carbon nanotubes (MWCNTs). The increased tensile strength (37.6%) and flexural strength (34.4%) are acquired in nano g-PS (0.0677 vol%)/MWCNTs (0.0335 vol%)/epoxy in contrast to pure epoxy. A remarkably improved tensile toughness up to 379.2% and an increased elongation at break up to 208.3% are obtained in this epoxy nanohybrid. The synergistic interactions among nano g-PS, MWCNTs and epoxy matrix as well as the state transition of nano g-PS from glassy state to fluid state provide an improved dispersion of nanofillers which is responsible for the increased electrical conductivity and enhanced mechanical properties. The decreased surface resistivity allows these nanohybrids to sufficiently dissipate surface charges as an antistatic material. This work provides an effective way to disperse carbon nanotubes with small amount of thermoplastic PS to simultaneously strengthen and toughen the thermosetting epoxy while introducing highly conductive function.
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Organoids derived from self‐organizing stem cells represent a major technological breakthrough with the potential to revolutionize biomedical research. However, building high‐fidelity organoids in a ...reproducible and high‐throughput manner remains challenging. Here, a droplet microfluidic system is developed for controllable fabrication of hybrid hydrogel capsules, which allows for massive 3D culture and formation of functional and uniform islet organoids derived from human‐induced pluripotent stem cells (hiPSCs). In this all‐in‐water microfluidic system, an array of droplets is utilized as templates for one‐step fabrication of binary capsules relying on interfacial complexation of oppositely charged Na‐alginate (NaA) and chitosan (CS). The produced hybrid capsules exhibit high uniformity, and are biocompatible, stable, and permeable. The established system enables capsule production, 3D culture, and self‐organizing formation of human islet organoids in a continuous process by encapsulating pancreatic endocrine cells from hiPSCs. The generated islet organoids contain islet‐specific α‐ and β‐like cells with high expression of pancreatic hormone specific genes and proteins. Moreover, they exhibit sensitive glucose‐stimulated insulin secretion function, demonstrating the capability of these binary capsules to engineer human organoids from hiPSCs. The proposed system is scalable, easy‐to‐operate, and stable, which can offer a robust platform for advancing human organoids research and translational applications.
Human organoids derived from self‐organizing stem cells represent a major technological breakthrough with the potential to revolutionize biomedical research. Here, a strategy is presented for fabricating hydrogel capsules in a droplet microfluidic system that enables 3D culture, growth, and massive generation of uniform islet organoids from human‐induced pluripotent stem cells in a reproducible manner to facilitate organoids research and therapy.
Brain organoids derived from human induced pluripotent stem cells can recapitulate the early stages of brain development, representing a powerful in vitro system for modeling brain development and ...diseases. However, the existing methods for brain organoid formation often require time-consuming procedures, including the initial formation of embryoid bodies (EBs) from hiPSCs, and subsequent neural induction and differentiation companied by multi-steps of cell transfer and encapsulation in a 3D matrix. Herein, we propose a simple strategy to enable in situ formation of massive brain organoids from hiPSCs on a micropillar array without tedious manual procedures. The optimized micropillar configurations allow for controlled EB formation, neural induction and differentiation, and generation of functional human brain organoids in 3D culture on a single device. The generated brain organoids were examined to imitate brain organogenesis in vivo at early stages of gestation with specific features of neuronal differentiation, brain regionalization, and cortical organization. By combining microfabrication techniques with stem cells and developmental biology principles, the proposed method can greatly simplify brain organoid formation protocols as compared to conventional methods, overcoming the potential limitations of cell contamination, lower throughput and variance of organoid morphology. It can also provide a useful platform for the engineering of stem cell organoids with improved functions and extending their applications in developmental biology, drug testing and disease modeling.
A novel and simple chip‐based microfluidic strategy is proposed for continuously controlled spinning of desirable hollow microfibers. These fabricated fiber‐shaped materials exhibit extraordinary ...morphological and structural complexity, as well as a heterogeneous composition. The resulting specific hollow microfibers have potential applications in numerous chemical and biomedical fields.
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