Microglial heterogeneity in the ischemic stroke mouse brain of both sexes.

BACKGROUND: Ischemic stroke elicits a complex and sustained immune response in the brain. Immunomodulatory treatments have long held promise for improving stroke outcomes, yet none have succeeded in the clinical setting. This lack of success is largely due to our incomplete understanding of how immune cells respond to stroke. The objective of the current study was to dissect the effect of permanent stroke on microglia, the resident immune cells within the brain parenchyma. METHODS: A permanent middle cerebral artery occlusion (pMCAO) model was used to induce ischemic stroke in young male and female mice. Microglia were sorted from fluorescence reporter mice after pMCAO or sham surgery and then subjected to single-cell RNA sequencing analysis. Various methods, including flow cytometry, RNA in situ hybridization, immunohistochemistry, whole-brain imaging, and bone marrow transplantation, were also employed to dissect the microglial response to stroke. Stroke outcomes were evaluated by infarct size and behavioral tests. RESULTS: First, we showed the morphologic and spatial changes in microglia after stroke. We then performed single-cell RNA sequencing analysis on microglia isolated from sham and stroke mice of both sexes. The data indicate no major sexual dimorphism in the microglial response to permanent stroke. Notably, we identified seven potential stroke-associated microglial clusters, including four major clusters characterized by a disease-associated microglia-like signature, a highly proliferative state, a macrophage-like profile, and an interferon (IFN) response signature, respectively. Importantly, we provided evidence that the macrophage-like cluster may represent the long-sought stroke-induced microglia subpopulation with increased CD45 expression. Lastly, given that the IFN-responsive subset constitutes the most prominent microglial population in the stroke brain, we used fludarabine to pharmacologically target STAT1 signaling and found that fludarabine treatment improved long-term stroke outcome. CONCLUSIONS: Our findings shed new light on microglia heterogeneity in stroke pathology and underscore the potential of targeting specific microglial populations for effective stroke therapies.

Investigation of Combustion and NO/SO2 Emission Characteristics during the Co-Combustion Process of Torrefied Biomass and Lignite.

This paper investigates the combustion characteristics and pollutant emission patterns of the mixed combustion of lignite (L) and torrefied pine wood (TPW) under different blending ratios. Isothermal combustion experiments were conducted in a fixed bed reaction system at 800 °C, and pollutant emission concentrations were measured using a flue gas analyzer. Using scanning electron microscopy (SEM) and BET (nitrogen adsorption) experiments, it was found that torrefied pine wood (TPW) has a larger specific surface area and a more developed pore structure, which can facilitate more complete combustion of the sample. The results of the non-isothermal thermogravimetric analysis show that with the TPW blending ratio increase, the entire combustion process advances, and the ignition temperature, maximum peak temperature, and burnout temperature all show a decreasing trend. The kinetic equations of the combustion reaction process of mixed gas were calculated by Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) kinetic equations. The results show that the blending of TPW reduces the activation energy of the combustion reaction of the mixed fuel. When the TPW blending ratio is 80%, the activation energy values of the mixed fuel are the lowest at 111.32 kJ/mol and 104.87 kJ/mol. The abundant alkali metal ions and porous structure in TPW reduce the conversion rates of N and S elements in the fuel to NO and SO2, thus reducing the pollutant emissions from the mixed fuel.

[Organic mercury tolerance, absorption and transformation in Spartina plants].

Critical concentration of methylmercuric chloride (MeHgCl) in the nutrient solution to which Spartina plants are tolerant is 15 micromol/L, three times higher than that of tobacco plants. After being treated with methylmercuric chloride, total quantity of organic mercury within plants increased and that of nutrient solution decreased greatly so that total quantity of inorganic mercury rose. It is inferred that Spartina plants absorb organic mercury and partially transform organic into inorganic mercury, and then more inorganic mercury is accumulated in underground parts of plants. In addition, inorganic mercury derived from organic mercury moved to solution by diffusion and permeation. In this way, the features Spartina plants exhibit in mercury accumulation and transformation from organic to inorganic mercury are valuable for phytoremediation of environment pollution.