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• Neuron damage occurred in the depression-like rats. • rTMS promoted normalization in the hippocampus. • rTMS intervention could protect hippocampal neurons. • NSCs were gradually replaced by astrocytes. Repetitive transcranial magnetic stimulation (rTMS) is a novel non-invasive neuromodulation technique with neuroprotective properties and is used to treat depression. However, the underlying mechanism of action remains unclear. In this study, we examined the possible mechanism mediating the antidepressant effect of rTMS using animal experiments. Specific pathogen-free rats were treated with rTMS after exposure to social isolation combined with chronic unpredictable mild stress (CUMS). After four weeks of CUMS, the rats exhibited a significant decrease in spatial working memory assessed using open-field testing, a general loss of interest assessed with the sucrose preference test, and a significant reduction in spatial recognition memory ability assessed using the Y-maze. These behavioral deficits were accompanied by decreased numbers of astrocytes in the hippocampus, decreased expression of glial fibrillary acidic protein (GFAP), increased numbers of neural stem cells (NSCs), and increased expression of nestin protein. These results indicated that neuron damage occurred in the depression-like rats. After rTMS intervention, the depression-like behavior was alleviated significantly, and the numbers of NSCs and astrocytes, as well as the expression of GFAP and nestin proteins, returned to normal levels. Overall, it is likely that attenuation of NSC proliferation and differentiation into astrocytes produced a neuroprotective effect on hippocampal neurons, which might partly explain the mechanism by which rTMS alleviates depression. [ABSTRACT FROM AUTHOR]

Ammonia-oxidizing prokaryotes (AOPs) are the major contributors of ammonia oxidization with widely distribution. Here we investigated the phylogenetic diversity, community composition, and regulating factors of AOPs in Jiaozhou Bay (JZB) with high-throughput sequencing of amoA gene. Phylogenetic analysis showed most of the OTUs could not be clustered with any known AOPs, indicating there might exist putative novel AOPs. With new developed protocols for AOP community analysis, we confirmed that only 3 OTUs of ammonia-oxidizing archaea (AOA) could be affiliated to known Nitrosopumilaceae and Nitrososphaera , and the other OTUs were identified as novel AOA based on the threshold. All abstained OTUs of ammonia-oxidizing bacteria (AOB) were identified as novel clusters based on the threshold. Further analysis showed the novel AOPs had different distribution characteristics related to environmental factors. The high abundance and widespread distribution of these novel AOPs indicated that they played an important role in ammonia conversion in eutrophic JZB. • The phylogenetic analysis showed the OTUs were distinct from known sequences, indicating that some putative novel AOPs might exist in JZB. • The new protocols were used to further confirm the existence of novel AOP and capture the bioinformation of them effectively. • The novel AOPs had different distribution characteristics related to environmental factors. • The novel AOPs with high abundance and widespread distribution should play an important role in the ammonia conversion in JZB. [ABSTRACT FROM AUTHOR]

Ammonia-oxidizing bacteria (AOB) catalyze the first step of nitrification, oxidizing ammonia to nitrite, and are characterized by amoA gene encoding ammonia monooxygenase. To analyze the AOB community effectively, an integral taxonomy database containing 14,058 amoA sequences and the optimal cut-off value at 95 % for OTU clustering were determined. This method was evaluated to be efficient by the analysis of environmental samples from the river, estuary, and sea. Using this method, a significant spatial variance of the AOB community was found. The diversity of AOB was highest in the estuary and lowest in the ocean. Nitrosomonas were the predominant AOB in the sediments of the freshwater river and estuary. Nearly all the AOB- amoA sequences belonged to uncultured bacterium in the sediments of deep sea. In general, an integral AOB taxonomic database and a suitable cut-off value were constructed for the comprehensive exploration of the diversity of AOB from river to sea. [Display omitted] • An integral taxonomy database was established for the processing of amplicon data of bacterial amoA gene. • 95 % was determined to be the optimal cut-off value for clustering bacterial amoA gene at the species level. • The spatial variance of the AOB community along the river, estuary and sea was revealed. [ABSTRACT FROM AUTHOR]

Research on the natural driving mechanism and trade-offs and synergies of ecosystem services (ES) is a prerequisite for the implementation of scientific integrated ecosystem management, especially in ecologically fragile alpine ecological barrier regions. This study mainly studies the spatiotemporal dynamics and natural driving mechanism of water yield (WY), soil conservation (SC), windbreak and sand fixation (WS) and carbon sequestration (CS) in the northeast of the Qinghai-Tibet Plateau, identifies the trade-off and synergy features between ES in horizontal space. The results showed that the distribution of four ES presents different geographical spatial patterns, and an obvious increasing trend during the study period. Seven natural factors (precipitation, temperature, windspeed, etc.) can explain 38.1～47.0% of the spatiotemporal dynamics of ES in 2000, 2010 and 2020. Vegetation characteristics and elevation are the main explanatory variables controlling ES spatial pattern with the total contribution rate of 29.3% in 2000 and 26.5% in 2010. Temperature and elevation are the two most critical natural factors affecting ES, with the contribution ratio of 29.9% in 2020. The contribution of single nature factor on each ES pattern is different in the same year, and show interannual changes in different year. The contributions of wind speed, precipitation and slope to SC are uncertain, and the effect of temperature on CS is nonlinear. The trade-off and synergy cluster areas are mostly agglomerated and embedded in the compatibility region, with the characteristics of regional differentiation. The trade-offs and synergies between ES generally present the characteristics of interannual fluctuation, except WY-SC and WS-CS, which show a weakening trend in 2000, 2010 and 2020. Based on the above findings, we further discussed the complex trade-off and synergy relationships of ES, and the results provide scientific support for sustainable development by creating win–win scenarios under future climate change trends. [Display omitted] • Different ecosystem services (ES) show different geographical spatial patterns. • EVI、DEM and temperature play a key role in the spatiotemporal dynamic of ES. • The impacts of single natural factor on spatiotemporal dynamics of each ES is different. • The trade-off and synergy between most of ES present interannual fluctuation. [ABSTRACT FROM AUTHOR]

Several home made and commercially available polyethylene (PE) samples grafted with maleic anhydride (MA) (PE-g-MA) were used as compatibilizer precursors (CPs) for the reactive blending of low density PE (LDPE) with polyamide-6 (PA). Scope of the work was to compare the effectiveness of these CPs with that of a number of ethylene–acrylic acid copolymers (EAA), which had been employed in a previous study for the reactive compatibilization of the same blends, and to get a deeper insight into the coupling reactions producing the PA-g-CP copolymers that are thought to act as the true compatibilizers in these systems. To this end, binary CP/LDPE and CP/PA and ternary LDPE/PA/CP blends were prepared with a Brabender mixer and were characterized by DSC, SEM and solvent fractionation. The results show that the PE-g-MA copolymers react more rapidly with PA than the EAA copolymers and that their CP effectiveness depends critically on the microstructure and the molar mass of their PE backbones. In particular, the CPs produced by functionalization of LDPE were shown to be miscible with this blend component and to be scarcely available at the interface where reaction with PA is expected to occur. Conversely, the CPs prepared from the HDPE grades were immiscible with LDPE and showed better CP performance. Whereas the effectiveness of the EAA copolymers studied earlier had been shown to increase with an increase in the concentration of the carboxyl groups, the concentration of the succinic anhydride groups of the PE-g-MA CPs studied in this work was found to play a minor role, at least in the investigated range (0.3–3.0 wt% MA). [Copyright &y& Elsevier]

• Water yield in Yellow River basin (YRB) showed an increasing trend during 2000, 2010 and 2019. • The contribution of land use/land cover change to water yield is lower than of precipitation in YRB. • Land greening in YRB resulted in benefits for water yield in recent years. • The contribution of turning green to water yield is various in different geomorphic units of YRB. Understanding the impacts of climate and land use/land cover (LULC) changes on water yield has great importance for water resource management and policy development, especially in arid and semi-arid areas. However, it is unclear whether land greening under the human land management is beneficial to the water yield of different geomorphic units under the unique climate models. Here, we used InVEST model to estimate the water yield of the Yellow River Basin (YRB) in 2000, 2010 and 2019 and selected different scenarios to analyse the contribution of LULC changes to water yield. The results showed that the water yield of the YRB increased during the study period. The mean depth of water yield (MDWY) of grassland, cultivated land, shrubland and forest decreased in turn, while the annual MDWY of each type increased. Cultivated land and grassland were the main contribution types of water yield in the YRB accounting for about 84% of the total, and the annual water yield of LULC types covered by vegetation increased except for cultivated land. The annual water yield of the Qinghai Tibet Plateau (region Ⅰ) and the Loess Plateau (region III) in the YRB accounted for more than 80% of the total YRB water yield and showed an interannual increasing trend with part of the Mongolia Plateau (region Ⅱ) in the basin. The contribution of LULC to water yield in the whole YRB was small compared with that of precipitation, but LULC changes resulted in benefits for water yield in recent years, especially in region III that is controlled by a warm-temperate semi-arid continental climate and region I that is controlled by a plateau cold climate. However, in region Ⅱ, which is controlled by a mid-temperate semi-arid continental climate, revegetation further weakened the water yield ecosystem service. The results can provide references for land use management to enhance water yield under the background of global climate change. [ABSTRACT FROM AUTHOR]

Rural settlements are carriers of ethnic culture, and their spatial morphology is restricted by the natural environment and ethnic culture, especially in areas where ethnic consciousness is strong. In this study, we selected multi-ethic communities in northwest China to analyze spatial morphology of rural settlements, and we described the relationship between ethnic culture and spatial morphology from the perspective of different ethnicities, leading industries, religious beliefs, and modern education. There were obvious geographical clustering characteristics and gradient variations in morphological structure of rural settlements in Qinghai Province, China. Spatial morphology of rural settlements in different multi-ethnic communities highlighted the ethnic characteristics of this unique nation, and it had an obvious relationship with their leading industries, modern education, and religious beliefs. The relationship between the spatial morphology of rural settlements and the leading economic activity revealed regular change in characteristics, from farming towns (F) to farming and animal husbandry towns (F-AH) to animal husbandry and farming towns (AH-F), and finally to animal husbandry towns (AH). The spatial morphology of other industrial towns (OI) did not show the coordinated regulation as did the other four categories, which showed the particularity of spatial morphology. All ethnic rural settlements had a significantly higher dependence on primary education than on religious beliefs. We concluded that educational resources will become an important factor in the future for optimizing the spatial pattern of rural settlements of multi-ethnic settlements in Northwest China. [ABSTRACT FROM AUTHOR]

Highlights: [•] DO limitation was commonly encountered in high cell density cultivation of DHA. [•] The cultures with more than 100g/L cell density exhibited shear-thinning behavior. [•] Apparent viscosity of the broth significantly affected the change of kLa. [•] OUR was proposed to be an on-line parameter for scale-up of DHA production. [ABSTRACT FROM AUTHOR]