125 research outputs found
Urban greenery and mental wellbeing in adults: Cross-sectional mediation analyses on multiple pathways across different greenery measures
Multiple mechanisms have been proposed to explain how greenery enhances their
mental wellbeing. Mediation studies, however, focus on a limited number of
mechanisms and rely on remotely sensed greenery measures, which do not
accurately capture how neighborhood greenery is perceived on the ground. To
examine: 1) how streetscape and remote sensing-based greenery affect people's
mental wellbeing in Guangzhou, China; 2) whether and, if so, to what extent the
associations are mediated by physical activity, stress, air quality and noise,
and social cohesion; and 3) whether differences in the mediation across the
streetscape greenery and NDVI exposure metrics occurred. Mental wellbeing was
quantified by the WHO-5 wellbeing index. Greenery measures were extracted at
the neighborhood level: 1) streetscape greenery from street view data via a
convolutional neural network, and 2) the NDVI remote sensing images. Single and
multiple mediation analyses with multilevel regressions were conducted.
Streetscape and NDVI greenery were weakly and positively, but not
significantly, correlated. Our regression results revealed that streetscape
greenery and NDVI were, individually and jointly, positively associated with
mental wellbeing. Significant partial mediators for the streetscape greenery
were physical activity, stress, air quality and noise, and social cohesion;
together, they explained 62% of the association. For NDVI, only physical
activity and social cohesion were significant partial mediators, accounting for
22% of the association. Mental health and wellbeing and both streetscape and
satellite-derived greenery seem to be both directly correlated and indirectly
mediated. Our findings signify that both greenery measures capture different
aspects of natural environments and may contribute to people's wellbeing by
means of different mechanisms
Evolutionary Enhancement of Zika Virus Infectivity in Aedes aegypti Mosquitoes
Zika virus (ZIKV) remained obscure until the recent explosive outbreaks in French Polynesia (2013-2014) and South America (2015-2016). Phylogenetic studies have shown that ZIKV has evolved into African and Asian lineages. The Asian lineage of ZIKV was responsible for the recent epidemics in the Americas. However, the underlying mechanisms through which ZIKV rapidly and explosively spread from Asia to the Americas are unclear. Non-structural protein 1 (NS1) facilitates flavivirus acquisition by mosquitoes from an infected mammalian host and subsequently enhances viral prevalence in mosquitoes. Here we show that NS1 antigenaemia determines ZIKV infectivity in its mosquito vector Aedes aegypti, which acquires ZIKV via a blood meal. Clinical isolates from the most recent outbreak in the Americas were much more infectious in mosquitoes than the FSS13025 strain, which was isolated in Cambodia in 2010. Further analyses showed that these epidemic strains have higher NS1 antigenaemia than the FSS13025 strain because of an alanine-to-valine amino acid substitution at residue 188 in NS1. ZIKV infectivity was enhanced by this amino acid substitution in the ZIKV FSS13025 strain in mosquitoes that acquired ZIKV from a viraemic C57BL/6 mouse deficient in type I and II interferon (IFN) receptors (AG6 mouse). Our results reveal that ZIKV evolved to acquire a spontaneous mutation in its NS1 protein, resulting in increased NS1 antigenaemia. Enhancement of NS1 antigenaemia in infected hosts promotes ZIKV infectivity and prevalence in mosquitoes, which could have facilitated transmission during recent ZIKV epidemics
Climatic Control on Plant and Soil d13C along an Altitudinal Transect of Lushan Mountain in Subtropical China: Characteristics and Interpretation of Soil Carbon Dynamics
<div><p>Decreasing temperature and increasing precipitation along altitude gradients are typical mountain climate in subtropical China. In such a climate regime, identifying the patterns of the C stable isotope composition (δ<sup>13</sup>C) in plants and soils and their relations to the context of climate change is essential. In this study, the patterns of δ<sup>13</sup>C variation were investigated for tree leaves, litters, and soils in the natural secondary forests at four altitudes (219, 405, 780, and 1268 m a.s.l.) in Lushan Mountain, central subtropical China. For the dominant trees, both leaf and leaf-litter δ<sup>13</sup>C decreased as altitude increased from low to high altitude, whereas surface soil δ<sup>13</sup>C increased. The lower leaf δ<sup>13</sup>C at high altitudes was associated with the high moisture-related discrimination, while the high soil δ<sup>13</sup>C is attributed to the low temperature-induced decay. At each altitude, soil δ<sup>13</sup>C became enriched with soil depth. Soil δ<sup>13</sup>C increased with soil C concentrations and altitude, but decreased with soil depth. A negative relationship was also found between O-alkyl C and δ<sup>13</sup>C in litter and soil, whereas a positive relationship was observed between aromatic C and δ<sup>13</sup>C. Lower temperature and higher moisture at high altitudes are the predominant control factors of δ<sup>13</sup>C variation in plants and soils. These results help understand C dynamics in the context of global warming.</p></div
3D multi-nozzle system with dual drives highly potential for 3D complex scaffolds with multi-biomaterials
Recently, additive manufacturing is one of the most focused research topics due to its explosive development, especially in
manufacturing engineering and medical science. In order to build 3D complex scaffolds with multi-biomaterials for clinical
application, a new 3D multi-nozzle system with dual-mode drives, i.e. ejection and extrusion was developed. In this paper,
much effort was made to gain fine control of droplet and excellent coordination during fabrication. Specifically, the parameters
that influence the size and stability of droplet most was intensively studied. Considering that the biomaterials used in the future
may have much difference in properties, the combination of parameters was investigated to facilitate the settings for certainsized
droplets, which are potentially eligible for bio-printing. The dispensing nozzles can work well both in independent and
convergent mode, which can be freely switched. Outstanding to the most currently used 3D bio-printing techniques, this system
can fabricate scaffolds with multi-materials of both low viscosity (by pneumatic dispensing) and high viscosity (through motor
extrusion). It is highly expected that this system can satisfy clinical application in the near future
Residential greenness, air pollution and psychological well-being among urban residents in Guangzhou, China
Different Response Mechanisms of Rhizosphere Microbial Communities in Two Species of Amorphophallus to Pectobacterium carotovorum subsp. carotovorum Infection
Soft rot is a widespread, catastrophic disease caused by Pectobacterium carotovorum subsp. carotovorum (Pcc) that severely damages the production of Amorphophallus spp. This study evaluated the rhizosphere bacterial and fungal communities in Pcc-infected and uninfected plants of two species of Amorphophallus, A. muelleri and A. konjac. Principal component analysis showed that the samples formed different clusters according to the Pcc infection status, indicating that Pcc infection can cause a large number of changes in the bacterial and fungal communities in the Amorphophallus spp. rhizosphere soil. However, the response mechanisms of A. muelleri and A. konjac are different. There was little difference in the overall microbial species composition among the four treatments, but the relative abundances of core microbiome members were significantly different. The relative abundances of Actinobacteria, Chloroflexi, Acidobacteria, Firmicutes, Bacillus, and Lysobacter were lower in infected A. konjac plants than in healthy plants; in contrast, those of infected A. muelleri plants were higher than those in healthy plants. For fungi, the relative abundances of Ascomycota and Fusarium in the rhizosphere of infected A. konjac plants were significantly higher than those of healthy plants, but those of infected A. muelleri plants were lower than those of healthy plants. The relative abundance of beneficial Penicillium fungi was lower in infected A. konjac plants than in healthy plants, and that of infected A. muelleri plants was higher than that of healthy plants. These findings can provide theoretical references for further functional research and utilization of Amorphophallus spp. rhizosphere microbial communities in the future
Progress on the Co-Pyrolysis of Coal and Biomass
In this chapter, the synergistic mechanism and the resulting influence during co-pyrolysis of coal and biomass, are summarized. The properties of coal and biomass, the release and migration of alkali and alkaline earth metals (AAEMs), the interaction between volatile and char, the characteristics of the resulting volatiles, and the physicochemical structure and reactivity of co-pyrolysis char, are also analyzed. In addition, the influence of AAEMs on the properties of the co-pyrolysis products is reviewed. Moreover, the analysis of the co-pyrolysis industry demonstration is also mentioned. Finally, this chapter also proposes some additional possibilities, based on further literature research
Amorphophallus muelleri activates ferulic acid and phenylpropane biosynthesis pathways to defend against Fusarium solani infection
Amorphophallus sp. is an economically important crop for rural revitalization in southwest China. However, Fusarium solani often infects Amorphophallus sp. corms during storage, damaging the corm quality and affecting leaf elongation and flowering in the subsequent crop. In this study, the mechanism of resistance to F. solani was investigated in the leaf bud and flower bud corms of Amorphophallus muelleri through transcriptome and metabolome analyses. A total of 42.52 Gb clean reads and 1,525 metabolites were detected in a total of 12 samples including 3 samples each of disease-free leaf bud corms (LC), leaf bud corms inoculated with F. solani for three days (LD), disease-free flower bud corms (FC), and flower bud corms inoculated with F. solani for three days (FD). Transcriptome, metabolome, and conjoint analyses showed that ‘MAPK signal transduction’, ‘plant-pathogen interaction’, ‘plant hormone signal transduction’, and other secondary metabolite biosynthesis pathways, including ‘phenylpropane biosynthesis’, ‘arachidonic acid metabolism’, ‘stilbene, diarylheptane and gingerolin biosynthesis’, and ‘isoquinoline alkaloids biosynthesis’, among others, were involved in the defense response of A. muelleri to F. solani. Ultimately, the expression of six genes of interest (AmCDPK20, AmRBOH, AmWRKY33, Am4CL, Am POD and AmCYP73A1) was validated by real-time fluorescence quantitative polymerase chain reaction, and the results indicated that these genes were involved in the response of A. muelleri to F. solani. Ferulic acid inhibited the growth of F. solani, reducing the harm caused by F. solani to A. muelleri corms to a certain extent. Overall, this study lays a strong foundation for further investigation of the interaction between A. muelleri and F. solani, and provides a list of genes for the future breeding of F. solani-resistant A. muelleri cultivars
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