课程文献中心 更多>>

关键词： fens   Sapric Histosols   bacteria   abundance   taxonomic structure   nitrogen fixation   denitrification   methanogenesis  

摘要： This article contains an analysis of structural and functional parameters of bacterial complexes taken for examination from complete profiles of fens assigned to the Klyukvennoe and Karbyshevskoe wetlands in Tomsk oblast. Bacteria in the fens are revealed throughout the entire profile. Their number determined by a direct method of fluorescence microscopy is high and varies from 27 to 78 × 109 cells/g of dry peat. The high number of saprotrophic bacteria (to 108–109 CFU/g of dry peat) is detected by the plate method. An increase in the number of saprotrophic bacteria down the fen profile is revealed. These data enable us to conclude for the first time that index k (a dimensionless universal characteristic of natural prokaryotic communities) in fen profiles decreases with depth. The bacterial cultures isolated from the fens studied are assigned to ten taxa: Bacillus, Streptomyces, Arthrobacter, Microbacterium, Pseudomonas, Flavobacterium, Dyadobacter, Janthinobacterium, Pedobacter, and Myxobacteriales. The acrotelm is dominated by bacterial cultures represented by genera Bacillus and Streptomyces; and Pseudomonas, Dyadobacter, and Arthrobacter are the dominants of the catotelm. The functions of bacterial genera and species identified by molecular biological methods are described. The study of nitrogen fixation, denitrification, and methanogenesis has shown that bacteria are viable and active throughout the entire peat profile.

关键词： Ecological status classification   EU Water Framework Directive   Multi-metric bioassessment   Multiple pressures   Very large river types   DIKEROGAMMARUS-VILLOSUS   AQUATIC ECOSYSTEMS   RUNNING WATERS   INDUCED WAVES   INVERTEBRATES   MANAGEMENT   SYSTEM   IMPACT   CHANNELIZATION   CONSERVATION  

摘要： Two factors complicate the ecological status classification of very large rivers in Europe according to the EU Water Framework Directive: First, current assessment methods do not fully consider the specific ecology of very large rivers (such as lateral connectivity and the role of floodplains for ecological status). Second, most of Europe's very large rivers have been severely altered by human activities such as flood protection, damming and navigation. The aim of our study is to develop an assessment method for very large rivers by identifying suitable biological metrics as the basis for multi-metric bioassessment using benthic invertebrates. Based on the pan-European typology of very large rivers by Borgwardt et al. (2019), we established a river type-specific assessment approach using invertebrate samples from 25 European countries and 94 very large rivers. The frequency and intensity of eight pressures jointly acting on the sampling sites were described, and a selection of suitable invertebrate community metrics were correlated with the pressure intensities to establish pressure-response relationships. The very large river types differ in terms of relevant pressures and pressure combinations, with the invertebrate communities distinctly responding to these pressure patterns. Neozoa dominance correlated strongly with 'navigation', being a major pressure at very large rivers, which entails severe hydro-morphological alterations such as channelization, riparian vegetation alteration and impoundment. Under combined pressures, a critical community turnover became evident in terms of neozoa outnumbering EPT taxa and the ratio of hemilimnic invertebrates decreasing. We propose ten bioassessment metrics, including measures of biological diversity as well as newly generated indicators, for the development of a European type-specific assessment method for very large rivers. (C) 2020 The Authors. Published by Elsevier B.V.

关键词： Classification   Computerized tomography   Endplate-disc complex injury   Magnetic resonance imaging   Osteoporotic vertebral fractures  

摘要： BackgroundThe purpose of this study was to use MRI and CT to observe osteoporosis vertebral fracture (OVF) combined with endplate-disc complex (EDC) injury and to classify the degree of EDC injury according to the changes in EDC signal intensity and morphology on the *** investigated the incidence of EDC injury, observed the morphology and signal intensity changes of EDC injury using MRI and CT, and graded the injuries from 0 to 4 according to their severity. We compared whether there were differences in the degree of EDC injury among different vertebral fractures, bone mineral density(BMD), and severity of vertebral *** total of 479 patients were included in this study, of whom 321 had EDC injury adjacent to the fractured vertebral body. Among those, 158 cases were grade 0, 66 cases were grade 1, 72 cases were grade 2, 78 cases were grade 3, and 92 cases were grade 4. The degree of EDC injury associated with thoracolumbar vertebral fractures was more serious than that of EDC injuries associated with thoracic and lumbar vertebral body fractures. Vertebral fractures with severe osteoporosis were associated with more severe EDC injury. Additionally, the more severe the vertebral fracture, the more severe was the combined EDC *** study found that the incidence rate of EDC injury reached 67.0%. Among patients with OVF, severe osteoporosis and severe fractures in the thoracolumbar segments were often associated with more severe EDC injury.

关键词： Neurotrophic growth   Cancer progression   microRNA   Tumor microenvironment   NERVE GROWTH-FACTOR   PERINEURAL INVASION   PANCREATIC-CANCER   MICROENVIRONMENT   PROLIFERATION   EXPRESSION   GUIDANCE   PROGRESSION   ACTIVATION   MECHANISMS  

摘要： Cancer neurobiology is an emerging discipline that inevitably unfurls new perspectives in oncology. The role that nerves play in cancer progression resonates with the long-reported dependency of tumors on neuro-molecular mechanisms that remain insufficiently elucidated. Whereas interactions between neurotrophic growth factors and receptors have been heavily studied in the nervous system, their expression in cancers and their impact on tumor cell growth and metastasis through their corresponding signaling pathways has been undervalued. Accumulating evidence suggests that trophic factors released by nerves strongly influence tumor development and that this neural contribution appears to not only play a stimulatory role but also function as an essential part of the tumor's microenvironment. This bidirectional communication between proliferating cells and tumor-infiltrating nerves drives axonogenesis and tumor growth and migration. Acquiring a better understanding of the trophic interactions between primary afferent neurons and invading tumors will guide clinically actionable strategies to prevent tumor-associated axonogenesis, disrupting the chemical crosstalk between neurons and tumors and ultimately decreasing tumor growth and spread.