The co-conversion of CO2 and CH4 into oxygenates with nonthermal plasma is attracting considerable interest, principally because this approach can overcome thermodynamic limitations and enables ...operation under mild conditions. However, plasma must be coupled with appropriate catalysts in order to achieve satisfactory oxygenate selectivities. In this article, the mechanisms underlying plasma-catalytic CO2 + CH4 conversion to three different types of oxygenates (CH3OH, HCHO, and CH3COOH) are discussed along the scales of reaction time (ns to ms) and dimension (nm to mm). Particular emphasis is given to the synergy between plasma-phase and surface reactions. In addition, typical materials (both catalytic and noncatalytic) and experimental setups that can affect the selectivities of oxygenated products are also highlighted.
Ammonia synthesis by plasma catalysis has emerged as an alternative process for decoupling nitrogen fixation from fossil fuels. Plasma activation can potentially circumvent the limitations of ...conventional thermocatalytic ammonia synthesis; however, the contribution of different reaction mechanisms to the production of ammonia at the catalyst surface remains unclear. Here, we identify the reaction intermediates adsorbed on γ-Al2O3-supported Ni and Fe catalysts during plasma-activated ammonia synthesis under various temperatures and reactor configurations using FTIR spectroscopy, steady-state flow reactor experiments, and computational kinetic modeling. Ammonia yield can be influenced by plasma-derived intermediates and their interactions with catalyst surfaces, which lead to different reaction pathways: Ni/γ-Al2O3 enhances plasma-promoted NH3 production and favors surface-adsorbed NH x species, while Fe/γ-Al2O3 shows the presence of N2H y and a lower overall concentration of N-containing adsorbates. Plasma–catalyst interactions are probed to reveal that elevated temperature and plasma irradiation of the surfaces promote NH3 desorption. The direct evidence of catalytic surface reactions occurring during a plasma-activated process provides mechanistic insight into plasma-activated ammonia synthesis.
Removal of organic micropollutants from water through advanced oxidation processes (AOPs) is hampered by the excessive input of energy and/or chemicals as well as the large amounts of residuals ...resulting from incomplete mineralization. Herein, we report a new water purification paradigm, the direct oxidative transfer process (DOTP), which enables complete, highly efficient decontamination at very low dosage of oxidants. DOTP differs fundamentally from AOPs and adsorption in its pollutant removal behavior and mechanisms. In DOTP, the nanocatalyst can interact with persulfate to activate the pollutants by lowering their reductive potential energy, which triggers a non-decomposing oxidative transfer of pollutants from the bulk solution to the nanocatalyst surface. By leveraging the activation, stabilization, and accumulation functions of the heterogeneous catalyst, the DOTP can occur spontaneously on the nanocatalyst surface to enable complete removal of pollutants. The process is found to occur for diverse pollutants, oxidants, and nanocatalysts, including various low-cost catalysts. Significantly, DOTP requires no external energy input, has low oxidant consumption, produces no residual byproducts, and performs robustly in real environmental matrices. These favorable features render DOTP an extremely promising nanotechnology platform for water purification.
Microglia, the resident myeloid cells of the central nervous system, play important roles in life-long brain maintenance and in pathology. Despite their importance, their regulatory dynamics during ...brain development have not been fully elucidated. Using genome-wide chromatin and expression profiling coupled with single-cell transcriptomic analysis throughout development, we found that microglia undergo three temporal stages of development in synchrony with the brain--early, pre-, and adult microglia--which are under distinct regulatory circuits. Knockout of the gene encoding the adult microglia transcription factor MAFB and environmental perturbations, such as those affecting the microbiome or prenatal immune activation, led to disruption of developmental genes and immune response pathways. Together, our work identifies a stepwise microglia developmental program integrating immune response pathways that may be associated with several neurodevelopmental disorders.
The intestinal microbiota undergoes diurnal compositional and functional oscillations that affect metabolic homeostasis, but the mechanisms by which the rhythmic microbiota influences host circadian ...activity remain elusive. Using integrated multi-omics and imaging approaches, we demonstrate that the gut microbiota features oscillating biogeographical localization and metabolome patterns that determine the rhythmic exposure of the intestinal epithelium to different bacterial species and their metabolites over the course of a day. This diurnal microbial behavior drives, in turn, the global programming of the host circadian transcriptional, epigenetic, and metabolite oscillations. Surprisingly, disruption of homeostatic microbiome rhythmicity not only abrogates normal chromatin and transcriptional oscillations of the host, but also incites genome-wide de novo oscillations in both intestine and liver, thereby impacting diurnal fluctuations of host physiology and disease susceptibility. As such, the rhythmic biogeography and metabolome of the intestinal microbiota regulates the temporal organization and functional outcome of host transcriptional and epigenetic programs.
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•Intestinal microbiota biogeography and metabolome undergo diurnal oscillations•Circadian oscillations of serum metabolites are regulated by the microbiota•Microbiota rhythms program the circadian epigenetic and transcriptional landscape•The microbiota regulates the circadian liver transcriptome and detoxification pattern
Diurnal oscillations in microbial localization and metabolite production in the gut have a major impact on the circadian epigenetic and transcriptional landscape of host tissues, not only locally, but also at distant sites such as the liver.
Climate change could have large implications for the management of dune-fringed coasts. Sea level rise and changes in storm wave and surge characteristics could lead to enhanced dune erosion and ...hence a decrease in safety levels. Here, we use the process-based model XBeach to quantify the impact of sea level rise and changing hydrodynamic boundary conditions on the magnitude of future dune erosion at two locations along the Dutch coast. We find a linear relation between sea level rise and dune erosion volume, the exact linear relation being dependent on the local hydrodynamical boundary conditions. The process driving higher erosion appears to be sea level rise, allowing waves to attack the dune at a higher level. Additional simulations illustrate that a change in the offshore wave angle, potentially produced by changes in storm tracks, could influence the erosion volume with the same order of magnitude as sea level rise. Finally, simulations with different mitigation options (i.e., sand nourishments) illustrate the strong effect of the location of the added sand to the reduction in the dune erosion volume.
Innate lymphoid cells (ILCs) are critical modulators of mucosal immunity, inflammation, and tissue homeostasis, but their full spectrum of cellular states and regulatory landscapes remains elusive. ...Here, we combine genome-wide RNA-seq, ChIP-seq, and ATAC-seq to compare the transcriptional and epigenetic identity of small intestinal ILCs, identifying thousands of distinct gene profiles and regulatory elements. Single-cell RNA-seq and flow and mass cytometry analyses reveal compartmentalization of cytokine expression and metabolic activity within the three classical ILC subtypes and highlight transcriptional states beyond the current canonical classification. In addition, using antibiotic intervention and germ-free mice, we characterize the effect of the microbiome on the ILC regulatory landscape and determine the response of ILCs to microbial colonization at the single-cell level. Together, our work characterizes the spectrum of transcriptional identities of small intestinal ILCs and describes how ILCs differentially integrate signals from the microbial microenvironment to generate phenotypic and functional plasticity.
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•Transcriptional and chromatin landscapes of innate lymphoid cells•Functional compartmentalization within ILC subsets revealed by single-cell RNA-seq•Impact of commensal microbiota on epigenetic regulation and gene expression of ILCs•Single-cell analysis of whole-transcriptome responses to microbial colonization
The gut ILC population is a lot more diverse than we thought, and this diversity requires constant signaling from the local microbiota.
Characterization of gene lists obtained from high-throughput genomic experiments is an essential task to uncover the underlying biological insights. A common strategy is to perform enrichment ...analyses that utilize standardized biological annotations, such as GO and KEGG pathways, which attempt to encompass all domains of biology. However, this approach provides generalized, static results that may fail to capture subtleties associated with research questions within a specific domain. Thus, there is a need for an application that can provide precise, relevant results by leveraging the latest research. We have therefore developed an interactive web application, Macrophage Annotation of Gene Network Enrichment Tool (MAGNET), for performing enrichment analyses on gene sets that are specifically relevant to macrophages. Using the hypergeometric distribution, MAGNET assesses the significance of overlapping genes with annotations that were curated from published manuscripts and data repositories. We implemented numerous features that enhance utility and user-friendliness, such as the simultaneous testing of multiple gene sets, different visualization options, option to upload custom datasets, and downloadable outputs. Here, we use three example studies compared against our current database of ten publications on mouse macrophages to demonstrate that MAGNET provides relevant and unique results that complement conventional enrichment analysis tools. Although specific to macrophage datasets, we envision MAGNET will catalyze developments of similar applications in other domains of interest. MAGNET can be freely accessed at the URL https://magnet-winterlab.herokuapp.com. Website implemented in Python and PostgreSQL, with all major browsers supported. The source code is available at https://github.com/sychen9584/MAGNET.
Epidermal mucus (‘mucus’) is increasingly applied to fish ecological studies based on stable isotope analysis (SIA) due to its non-invasive collection. However, knowledge on mucus SI turnover rates ...of individual fish remains limited, including uncertainty over how they are influenced by fish body sizes. Here, a diet switch experiment predicted mucus SI turnover rates (δ
13
C and δ
15
N) as a function of time using samples taken over 200 days from 10 individually tagged common carp
Cyprinus carpio
covering two size groups. Non-linear mixed effects models revealed rapid turnover of both δ
13
C and δ
15
N (
T
50
: 2–5 days;
T
95
: 9–22 days); δ
15
N turnover rates were slower for the larger cohort, while δ
13
C turnover rates were independent of body size. Within size groups, turnover rates were not expected to vary between individuals. These experimental results suggest that due to these fast turnover rates, epidermal mucus can provide insights into the diets of fish over very short timeframes, although for δ
15
N the body size of the fish needs consideration.
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