93 research outputs found

    The role of environmental conditions, climatic factors and spatial processes in driving multiple facets of stream macroinvertebrate beta diversity in a climatically heterogeneous mountain region

    Get PDF
    Highlights • We tested patterns of multi-faceted beta diversity across mountain streams. • All three facets of beta diversities increase from the north slope to south slope. • Spatial variables were most important in structuring three facets of beta diversity. • Functional and phylogenetic beta diversity complement to taxonomic beta diversity. • Combining multi-faceted biodiversity is essential for management and conservation.There is a growing recognition that examining patterns of ecological communities and their underlying determinants is not only feasible based on taxonomic data, but also functional and phylogenetic approaches. This is because these additional facets can enhance the understanding of the relative contribution of multiple processes in shaping biodiversity. However, few studies have focused on multifaceted beta diversities in lotic macroinvertebrates, especially when considering driving factors operating at multiple spatial scales. Here, we examined the spatial patterns of multi-faceted (i.e., taxonomic, functional and phylogenetic) beta diversity and their components (i.e., turnover and nestedness) of macroinvertebrates in 50 sites in 10 streams situated in the north and south slope of the Qinling Mountains, the geographical dividing line of Northern and Southern China. We found that the streams draining the north slope showed significantly lower values of beta diversity based on all three facets than the streams draining the south slope. Such north-to-south increases of beta diversity were caused by the distinct climatic and local environmental conditions between the sides of the mountain range. Moreover, spatial variables generally played the most important role in structuring all facets and components of beta diversity, followed by local environmental and climatic variables, whereas catchment variables were less important. Despite the similar results of relative contribution of explanatory variables on each beta diversity facet, the details of community-environment relationships (e.g., important explanatory variables and explanatory power) were distinct among different diversity facets and their components. In conclusion, measuring functional and phylogenetic beta diversity provides complementary information to traditional taxonomic approach. Therefore, an integrative approach embracing multiple facets of diversity can better reveal the mechanisms shaping biodiversity, which is essential in assessing and valuing aquatic ecosystems for biodiversity management and conservation

    Long-term satellite observations show continuous increase of vegetation growth enhancement in urban environment

    Get PDF
    Urbanization shows continuous expansion and development, ushering in the co-evolution of urban environments and vegetation over time. Recent remote sensing-based studies have discovered prevalent vegetation growth enhancement in urban environments. However, whether there is a temporal evolution of the growth enhancement remains unknown and unexplored. Here we expanded the existing framework for assessing the long-term impact of urbanization on vegetation greenness (enhanced vegetation index, EVI) using long time series of remote sensing images and applied it in Changsha, the capital city of Hunan province in China. Results showed that vegetation growth experienced widespread enhancement from 2000 to 2017, and increased 1.8 times from 2000 to 2017, suggesting strong continuous adaptive capability of vegetation to urban conditions. Although the overall impact of urbanization was negative due to the replacement of vegetated surfaces, the growth enhancement nevertheless offset or compensated the direct loss of vegetated cover during urbanization in the magnitude of 28% in 2000 to 44% in 2017. Our study also revealed large spatial heterogeneity in vegetation growth response among various districts at different urbanization levels and found an emergent trend under the observed spatial heterogeneity toward an asymptotic maximum with urbanization, showing EVI converges to 0.22 in highly urbanized areas. We further found that the positive effect of urbanization on vegetation growth is a function of urbanization intensity and time, which implies that the effect of the urban environment on vegetation can be simulated and predicted, and can be verified in more cities in the future. Our study is the first to successfully quantify long-term spatial patterns on the co-evolution of urbanization and vegetation, providing a new understanding of the continuous adaptive responses of vegetation growth to urbanization and shedding light on predicting 24 biological responses to future environmental change

    Liquid gating elastomeric porous system with dynamically controllable gas/liquid transport

    Get PDF
    【Abstract】The development of membrane technology is central to fields ranging from resource harvesting to medicine, but the existing designs are unable to handle the complex sorting of multiphase substances required for many systems. Especially, the dynamic multiphase transport and separation under a steady-state applied pressure have great benefits for membrane science, but have not been realized at present. Moreover, the incorporation of precisely dynamic control with avoidance of contamination of membranes remains elusive. We show a versatile strategy for creating elastomeric microporous membrane-based systems that can finely control and dynamically modulate the sorting of a wide range of gasesandliquids underasteady-stateapplied pressure,nearlyeliminate fouling,and can be easily applied over many size scales, pressures, and environments. Experiments and theoretical calculation demonstrate the stability of our system and the tunability of the critical pressure. Dynamic transport of gas and liquid can be achieved through our gating interfacial design and the controllable pores’ deformation without changing the applied pressure. Therefore, we believe that this system will bring new opportunities for many applications, such as gas-involved chemical reactions, fuel cells, multiphase separation, multiphase flow, multiphase microreactors, colloidal particle synthesis, and sizing nano/microparticles.This work was supported by the National Natural Science Foundation of China (grant no. 21673197), the Young Overseas High-level Talents Introduction Plan, the 111 Project (grant no. B16029). 研究工作得到国家自然科学基金委(项目批准号:21673197)和厦门大学校长基金(项目批准号:20720170050)等资助与支持

    Mulberry Extracts Alleviate A β

    Get PDF
    Mulberry, which contained high amounts of anthocyanins, has been used in traditional Chinese medicine. Mulberry fruit extracts (ME) have demonstrated the antioxidant activity and neuroprotection. The study was to investigate the neuroprotective efficacy of ME against β-amyloid 25–35- (Aβ25–35-) induced PC12 cells injury. Cells preincubated with or without ME (200 μg/mL) for 24 h were treated with Aβ25–35 (20 μmol/L) for another 24 h. Cell viability was assessed by MTT, gene expression profiles were examined by cDNA microarrays, and RT-PCR were used to confirm the results of microarray assays. ME pretreatment was found to neutralize the cytotoxicity and prevent Aβ25–35-induced cells injury. Analyses of gene expression profile revealed that genes involving cell adhesion, peptidase activity, cytokine activity, ion binding activity, and angiogenesis regulation were significantly modulated by ME pretreatment. Among those genes, Apaf1, Bace2, and Plcb4 were enriched in the “Alzheimer’s disease-reference pathway” and downregulated after ME intervention. RT-PCR results showed that ME preincubation could significantly inhibit Aβ25–35 increased mRNA levels of these three genes. Overall, ME pretreatment could substantially alleviate PC12 cells injury and downregulate expression of AD-related genes, such as Apaf1, Bace2, and Plcb4. This study has a great nutrigenomics interest and brings new and important light in the field of AD intervention

    E6 Protein Expressed by High-Risk HPV Activates Super-Enhancers of the EGFR and c-MET Oncogenes by Destabilizing the Histone

    Get PDF
    The high-risk (HR) human papillomaviruses (HPV) are causative agents of anogenital tract dysplasia and cancers and a fraction of head and neck cancers. The HR HPV E6 oncoprotein possesses canonical oncogenic functions, such as p53 degradation and telomerase activation. It is also capable of stimulating expression of several oncogenes, but the molecular mechanism underlying these events is poorly understood. Here, we provide evidence that HPV16 E6 physically interacts with histone H3K4 demethylase KDM5C, resulting in its degradation in an E3 ligase E6AP- and proteasome-dependent manner. Moreover, we found that HPV16-positive cancer cell lines exhibited lower KDM5C protein levels than HPV-negative cancer cell lines. Restoration of KDM5C significantly suppressed the tumorigenicity of CaSki cells, an HPV16-positive cervical cancer cell line. Whole genome ChIP-seq and RNA-seq results revealed that CaSki cells contained super-enhancers in the proto-oncogenes EGFR and c-MET. Ectopic KDM5C dampened these super-enhancers and reduced the expression of proto-oncogenes. This effect was likely mediated by modulating H3K4me3/H3K4me1 dynamics and decreasing bidirectional enhancer RNA transcription. Depletion of KDM5C or HPV16 E6 expression activated these two super-enhancers. These results illuminate a pivotal relationship between the oncogenic E6 proteins expressed by HR HPV isotypes and epigenetic activation of super-enhancers in the genome that drive expression of key oncogenes like EGFR and c-MET. Significance: This study suggests a novel explanation for why infections with certain HPV isotypes are associated with elevated cancer risk by identifying an epigenetic mechanism through which E6 proteins expressed by those isotypes can drive expression of key oncogenes.</p

    Model-Based Fault Diagnosis of Actuators in Electronically Controlled Air Suspension System

    No full text
    The air suspension adjusts the height of the vehicle body through charging and bleeding air to meet the high performance of the vehicle, which needs a reliable electronic control system. Through fault tree analysis of the electronically controlled air suspension (ECAS) system and considering the correlation between the duty cycle and flow rate of the air spring solenoid valve, the fault model of the solenoid valve is constructed, and the fault diagnosis design method of the ECAS system solenoid valve based on multiple extended Kalman filter banks (EKFs) is proposed. An adaptive threshold is used to realize fault diagnosis, and active fault-tolerant control is carried out based on an analytical model. The real controller based on d2p rapid prototyping technology and the vehicle model based on AMESim are further verified on the hardware-in-the-loop (HiL) simulation test platform and compared with the pure simulation results. The test results show that the fault diagnosis and fault-tolerant control algorithm can work normally in the actual controller, and can effectively realize the fault diagnosis and fault-tolerant control of the actuator in the vehicle ECAS system

    Effect of mineral admixtures on flow properties of fresh cemented paste backfill: Assessment of time dependency and thixotropy

    No full text
    YILMAZ, EROL/0000-0001-8332-8471WOS: 000558906000025Cemented paste backfill (CPB), an engineered mix consisting typically of tailings, cement and water, has become a regularly used structural material in most mines worldwide. the performance of the CPB structure is dependent both on the quality of each constituent and the rheological behavior of fresh CPB during placement into mined-out voids. A connection between the bacldill's rheological behavior and the structural changes governing thixotropy and structural breakdown can provide a better understanding of the different yield stress-viscosity results. in this study, the mineral admixture effect on theological properties of fresh CPB slurry is studied by considering a combined assessment of time dependency and thixotropy. A total of three mineral admixtures such as fly ash (FA), granulated blast furnace slag (Slag) and silica fume (SF) were used for the preparation of CPB material. the theological parameters, mainly yield stress and plastic viscosity, were examined by the Bingham model. Results indicate that the thixotropy of fresh CPB decreases with FA dosage, while the addition of Slag and SF gives lower thixotropy values at early ages, and a higher rate of thixotropy acquisition at a later age. A partial replacement of cement with FA leads to an increase in the static de formability and significant improvement in fluidity of CM, and a plot of thixotropy versus plastic viscosity results in a linear correlation between them. Moreover, the addition of slag particles reduces the yield stress and plastic viscosity of CPB, while SF-containing CPB exhibits improved yield stress and lower plastic viscosity. Plotting thixotropy versus plastic viscosity generates a poor linear relation for SF- and Slag-containing CPB slurries. the findings of this study will be useful in the lucrative design, efficient operation and safe production of early-age CPB material. (C) 2020 Elsevier B.V. All rights reserved.National Natural Science Foundation of ChinaNational Natural Science Foundation of China (NSFC) [51804063]; China Postdoctoral Science FoundationChina Postdoctoral Science Foundation [2019M652426]The authors would like to sincerely acknowledge the financial support of the National Natural Science Foundation of China (Grant No 51804063) and the China Postdoctoral Science Foundation (Grant No 2019M652426)
    corecore