Perovskite nanocrystals have attracted much attention in the last ten years due to their different applications, especially in the photovoltaic domain and LED performance. In this large family of perovskite nanocrystals, CsPbBr3 nanocrystals are attractive nanomaterials because they are good candidates for obtaining green emissions and exploring new synthesis routes. In this context, controlling the nanometric scale's morphology, particularly the size and monodispersity, is fundamental for exploring their photophysical properties and final applications. Currently, the nanometric size of nanocrystals is ensured by the presence of oleic acid and oleylamine molecules, in using Hot Injection (HI) or ligand-assisted reprecipitation (LARP) methods. If oleic acid plays a fundamental role, oleylamine can be easily substituted by other amino molecules, opening the way for the functionalization of CsPbBr3 nanocrystals and the obtention of new hybrid perovskite nanocrystal families. In this article, we describe the synthesis, by soft chemistry, of a new family of hybrid organic-inorganic CsPbBr3 nanocrystals, functionalized by aryl-alkylamine (AAA) molecules, through the modified LARP method. We highlight the mechanism for cutting submicron crystals into nanocrystals, using aryl-alkylamine molecules like scissors. The impact of these amino molecules on the final nanocrystals leads to different nanocrystal morphologies (nanocubes, nanosheets, or nanorods) and structures (monoclinic, rhombohedral, or tetragonal). In addition, this modified LARP method highlights, under certain experimental conditions, an unexpected formation of PbO ribbons.

Lakes and reservoirs globally are experiencing unprecedented changes in land use and climate, depleting dissolved oxygen (DO) in the bottom waters (hypolimnia) of these ecosystems. Because DO is the most energetically favorable terminal electron acceptor (TEA) for organic carbon mineralization, its availability controls the onset of alternate TEA pathways (for example, denitrification, manganese reduction, iron reduction, sulfate reduction, methanogenesis). Low DO concentrations can trigger organic carbon mineralization via alternate TEA pathways in the water column and sediments, which has important implications for greenhouse gas production [carbon dioxide (CO2) and methane (CH4)]. In this study, we experimentally injected supersaturated DO into the hypolimnion of a eutrophic reservoir and measured concentrations of TEAs and terminal electron products (TEPs) in the experimental reservoir and an upstream reference reservoir. We calculated the electron equivalents yielded from each TEA pathway and estimated the contributions of each TEA pathway to organic carbon processing in both reservoirs. DO additions to the hypolimnion of the experimental reservoir promoted aerobic respiration, suppressing most alternate TEA pathways and resulting in elevated CO2 accumulation. In comparison, organic carbon mineralization in the reference reservoir's anoxic hypolimnion was dominated by alternate TEA pathways, resulting in both CH4 and CO2 accumulation. Our ecosystemscale experiments demonstrate that the alternate TEA pathways that succeed aerobic respiration in lakes and reservoirs can be manipulated at the ecosystem scale. Moreover, changes in the DO dynamics of freshwater lakes and reservoirs may result in concomitant changes in the redox reactions in the water column that control organic carbon mineralization and greenhouse gas accumulation.

The US National Ecological Observatory Network's (NEON's) standardized monitoring program provides an unprecedented opportunity for comparing the predictability of ecosystems. To harness the power of NEON data for examining environmental predictability, we scaled a near-term, iterative, water temperature forecasting system to all six NEON lakes in the conterminous US. We generated 1-day-ahead to 35-days-ahead forecasts using a process-based hydrodynamic model that was updated with observations as they became available. Among lakes, forecasts were more accurate than a null model up to 35-days-ahead, with an aggregated 1-day-ahead root-mean square error (RMSE) of 0.61 degrees C and a 35-days-ahead RMSE of 2.17 degrees C. Water temperature forecast accuracy was positively associated with lake depth and water clarity, and negatively associated with fetch and catchment size. The results of our analysis suggest that lake characteristics interact with weather to control the predictability of thermal structure. Our work provides some of the first probabilistic forecasts of NEON sites and a framework for examining continental-scale predictability.

Animals have evolved two defense strategies to survive infections. Antagonistic strategies include mechanisms of immune resistance that operate to sense and kill invading pathogens. Cooperative or physiological defenses mediate host adaptation to the infected state, limiting physiological damage and disease, without killing the pathogen, and have been shown to cause asymptomatic carriage and transmission of lethal pathogens. Here we demonstrate that physiological defenses cooperate with the adaptive immune response to generate long-term asymptomatic carriage of the lethal enteric murine pathogen, Citrobacter rodentium. Asymptomatic carriage of genetically virulent C. rodentium provided immune resistance against subsequent infections. Host immune protection was dependent on systemic antibody responses and pathogen virulence behavior, rather than the recognition of specific virulent factor antigens. Finally, we demonstrate that an avirulent strain of C. rodentium in the field has background mutations in two genes that are important for LPS structure. Our work reveals novel insight into how asymptomatic infections can arise mechanistically with immune resistance, mediating exclusion of phenotypically virulent enteric pathogen to promote asymptomatic carriage.

Animals have evolved two defense strategies to survive infections. Antagonistic strategies include mechanisms of immune resistance that operate to sense and kill invading pathogens. Cooperative or physiological defenses mediate host adaptation to the infected state, limiting physiological damage and disease, without killing the pathogen, and have been shown to cause asymptomatic carriage and transmission of lethal pathogens. Here we demonstrate that physiological defenses cooperate with the adaptive immune response to generate long-term asymptomatic carriage of the lethal enteric murine pathogen, Citrobacter rodentium. Asymptomatic carriage of genetically virulent C. rodentium provided immune resistance against subsequent infections. Host immune protection was dependent on systemic antibody responses and pathogen virulence behavior, rather than the recognition of specific virulent factor antigens. Finally, we demonstrate that an avirulent strain of C. rodentium commonly used in the field has background mutations in two genes that are important for LPS structure, which may complicate interpretations of previous studies in the field. Our work reveals novel insight into how asymptomatic infections can arise mechanistically with immune resistance, mediating exclusion of phenotypically virulent enteric pathogen to promote asymptomatic carriage.

Animals evolved two defense strategies to survive infections. Antagonistic strategies include immune resistance mechanisms that operate to kill invading pathogens. Cooperative or physiological defenses mediate host adaptation to the infected state, limiting physiological damage and disease, without killing the pathogen, and have been shown to cause asymptomatic carriage and transmission of lethal pathogens. Here, we demonstrate that physiological defenses cooperate with the adaptive immune response to generate long-term asymptomatic carriage of the lethal enteric murine pathogen, Citrobacter rodentium. Asymptomatic carriage of genetically virulent C. rodentium provided immune resistance against subsequent infections. Immune protection was dependent on systemic antibody responses and pathogen virulence behavior rather than the recognition of specific virulent antigens. Last, we demonstrate that an avirulent strain of C. rodentium in the field has background mutations in genes that are important for LPS structure. Our work reveals insight into how asymptomatic infections can arise mechanistically with immune resistance, mediating exclusion of phenotypically virulent enteric pathogen to promote asymptomatic carriage.

Animals evolved two defense strategies to survive infections. Antagonistic strategies include immune resistance mechanisms that operate to kill invading pathogens. Cooperative or physiological defenses mediate host adaptation to the infected state, limiting physiological damage and disease, without killing the pathogen, and have been shown to cause asymptomatic carriage and transmission of lethal pathogens. Here, we demonstrate that physiological defenses cooperate with the adaptive immune response to generate long-term asymptomatic carriage of the lethal enteric murine pathogen, Citrobacter rodentium. Asymptomatic carriage of genetically virulent C. rodentium provided immune resistance against subsequent infections. Immune protection was dependent on systemic antibody responses and pathogen virulence behavior rather than the recognition of specific virulent antigens. Last, we demonstrate that an avirulent strain of C. rodentium in the field has background mutations in genes that are important for LPS structure. Our work reveals insight into how asymptomatic infections can arise mechanistically with immune resistance, mediating exclusion of phenotypically virulent enteric pathogen to promote asymptomatic carriage.

Nematodes of the genus Steinernema and their Xenorhabdus bacterial symbionts are lethal entomopathogens that are useful in the biocontrol of insect pests, as sources of diverse natural products, and as research models for mutualism and parasitism. Xenorhabdus play a central role in all aspects of the Steinernema lifecycle, and a deeper understanding of their genomes therefore has the potential to spur advances in each of these applications. Results: Here, we report a comparative genomics analysis of Xenorhabdus griffiniae, including the symbiont of Steinernema hermaphroditum nematodes, for which genetic and genomic tools are being developed. We sequenced and assembled circularized genomes for three Xenorhabdus strains: HGB2511, ID10 and TH1. We then determined their relationships to other Xenorhabdus and delineated their species via phylogenomic analyses, concluding that HGB2511 and ID10 are Xenorhabdus griffiniae while TH1 is a novel species. These additions to the existing X. griffiniae landscape further allowed for the identification of two subspecies within the clade. Consistent with other Xenorhabdus, the analysed X. griffiniae genomes each encode a wide array of antimicrobials and virulence-related proteins. Comparative genomic analyses, including the creation of a pangenome, revealed that a large amount of the intraspecies variation in X. griffiniae is contained within the mobilome and attributable to prophage loci. In addition, CRISPR arrays, secondary metabolite potential and toxin genes all varied among strains within the X. griffiniae species. Conclusions: Our findings suggest that phage-related genes drive the genomic diversity in closely related Xenorhabdus symbionts, and that these may underlie some of the traits most associated with the lifestyle and survival of entomopathogenic nematodes and their bacteria: virulence and competition. This study establishes a broad knowledge base for further exploration of not only the relationships between X. griffiniae species and their nematode hosts but also the molecular mechanisms that underlie their entomopathogenic lifestyle.

Temperature dependent-electrical resistance of n-type Bi2Te3 was investigated under high pressure. Superconductivity was detected at 4.9 GPa with Tc-onset = 2.8 K. Resistance and T-c suggest that there are two electronic phase transitions below 10 GPa. We conjecture that the bulk insulating phase first changes to semimetal and then to metal. The evolution of the Hall coefficient is qualitatively consistent with the proposed electronic phase transition. The origin of superconductivity and topological properties are also discussed. Published by AIP Publishing.

Long-term ground LAI measurements from the global networks of sites (e.g. FLUXNET) have emerged as a promising data source to validate remotely sensed global LAI product time-series. However, the spatial scale-mismatch issue between site and satellite observations hampers the use of such invaluable ground measurements in validation practice. Here, we propose an approach (Grading and Upscaling of Ground Measurements, GUGM) that integrates a spatial representativeness grading criterion and a spatial upscaling strategy to resolve this scale-mismatch issue and maximize the utility of time-series of site-based LAI measurements. The performance of GUGM was carefully evaluated by comparing this method to both benchmark LAI and other widely used conventional approaches. The uncertainty of three global LAI products (i.e. MODIS, GLASS and GEOV1) was also assessed based on the LAI time-series validation dataset derived from GUGM. Considering all the evaluation results together, this study suggests that the proposed GUGM approach can significantly reduce the uncertainty from spatial scale mismatch and increase the size of the available validation dataset. In particular, the proposed approach outperformed other widely used approaches in these two respects. Furthermore, GUGM was successfully implemented to validate global LAI products in various ways with advantaging frequent time-series validation dataset. The validation results of the global LAI products show that GLASS has the lowest uncertainty, followed by GEOV1 and MODIS for the overall biome types. However, MODIS provides more consistent uncertainties across different years than GLASS and GEOV1. We believe that GUGM enables us to better understand the structure of LAI product uncertainties and their evolution across seasonal or annual contexts. In turn, this method can provide fundamental information for further LAI algorithm improvements and the broad application of LAI product time-series.