Recent advances of nanofluids in micro/nano scale energy transportation

As the continuing integration and size deflation of component dimensions in electronic circuits and increase in the number of transistors in modern microprocessor chips, especially for heat dissipation of micro/nano scale devise, traditionally used single phase fluid cannot meet the requirements for highly efficient heat transfer, which thus frequently results in the damage of electrical devices. Consequently, thermal conductivity enhancement of working fluids is of great significance for advanced thermal energy conservation and conversion. Nanofluids, which possess a superior thermal conductive performance, are studied towards an alternative to the traditionally used working fluids, have attracted ample attention within the past decades. In this paper, firstly, we summarized the recent progress in the preparation of nanofluids, in particular for a method involving a covalent concerning reorganization or generation; subsequently, the utilization of nanofluids in hitherto unsummerized micro/nano scale heat and mass transfer fields, especially for some chemistry relating applications were discussed. All works demonstrated in this review are aiming at clarifying the fact that advanced material technologies are required in preparation of recent nanofluids on the premise of continuing harsh energy transfer situation; on the other hand, nanofluids were also able to offer insights for novel micro/nano scale energy transportation which has not yet been reviewed before

Exploring the ecological quality and its drivers based on annual remote sensing ecological index and multisource data in Northeast China

The remote sensing ecological index (RSEI) has been established as a comprehensive indicator to evaluating long–term ecological quality (EQ) changes. However, previous studies mostly focused on EQ change analysis at discrete time points and ignored the continuous process. This study aims to construct an annual EQ collection from 2000 to 2019 to reveal the spatial and temporal changes in EQ under the combined action of multiple factors. We developed annual RSEI in Northeast China based on Google Earth Engine and described the patterns of EQ changes from 2000 to 2019 using trend analysis. Furthermore, we quantified the contributions of natural and anthropogenic driving factors and their interactions on EQ changes utilizing the geographical detector model. The results showed that the EQ of Northeast China improved from Moderate to Good over 2000–2019, with RSEI increasing from 0.54 to 0.67. The pixel-based trend analysis suggested that the regions with stable and improved EQ accounted for 52.57% and 46.73%, respectively. EQ improvements were mostly found in cropland, grassland, and woodland. EQ deterioration areas only accounted for 0.70% and mainly occurred in urban, coastal, and sandy areas. Among the nine driving factors, elevation, land use intensity, and slope were the primary factors for EQ improvement, with contributions of 20%, 16%, and 13% in Northeast China, respectively, while the eco-engineering area explained 32% of the negative effect on EQ deterioration. Compared with the contribution of a single factor, the multi-factor interactions significantly enhanced those factors’ explanatory power for EQ variations. The results of this study will provide significant information and important reference for decision-makers to make more targeted efforts on environmental protection and ecological restoration

Multifunctional CO3S4/graphene composites for lithium ion batteries and oxygen reduction reaction

Cobalt sulfide is a good candidate for both lithium ion batteries (LIBs) and cathodic oxygen reduction reaction (ORR), but low conductivity, poor cyclability, capacity fading, and structural changes hinder its applications. The incorporation of graphene into CO3S4 makes it a promising electrode by providing better electrochemical coupling, enhanced conductivity, fast mobility of ions and electrons, and a stabilized structure due to its elastic nature. With the objective of achieving high-performance composites, herein we report a facile hydrothermal process for growing CO 3S4 nanotubes (NTs) on graphene (G) sheets. Electrochemical impedance spectroscopy (EIS) verified that graphene dramatically increases the conductivity of the composites to almost twice that of pristine CO3S4. Electrochemical measurements indicated that the as-synthesized CO3S4/ G composites exhibit good cyclic stability and a high discharge capacity of 720 mAhg1 up to 100 cycles with 99.9% coulombic efficiency. Furthermore, the composites react with dissolved oxygen in the ORR by fourand two-electron mechanisms in both acidic and basic media with an onset potential close to that of commercial Pt/C. The stability of the composites is much higher than that of Pt/C, and exhibit high methanol tolerance. Thus, these properties endorse CO3S4/G composites as auspicious candidates for both LIBs and ORR. 2013 Wiley-VCH Verlag GmbHandCo

Continuous Tracking of Forest Disturbance and Recovery in the Greater Khingan Mountains from Annual Landsat Imagery

Understanding accurate and continuous forest dynamics is of key importance for forest protection and management in the Greater Khingan Mountains (GKM). There has been a lack of finely captured and long-term information on forest disturbance and recovery since the mega-fire of 1987 which may limit the scientific assessment of the GKM’s vegetation conditions. Therefore, we proposed a rapid and robust approach to track the dynamics of forest disturbance and recovery from 1987 to 2021 using Landsat time series, LandTrendr, and random forests (RF) models. Furthermore, we qualified the spatial characteristics of forest changes in terms of burn severity, topography, and distances from roads and settlements. Our results revealed that the integrated method of LandTrendr and RF is well adapted to track forest dynamics in the GKM, with an overall accuracy of 0.86. From 1987 to 2021, forests in the GKM showed a recovery trend with a net increase of more than 4.72 × 104 ha. Over 90% of disturbances occurred between 1987 and 2010 and over 75% of recovery occurred between 1987 and 1988. Mildly burned areas accounted for 51% of forest disturbance and severely burned areas contributed to 45% of forest recovery. Forest changes tended to occur in zones with elevations of 400–650 m, slopes of less than 9°, and within 6 km of roads and 24 km of settlements. Temporal trends of forest disturbance and recovery were mainly explained by the implementation timelines of major forestry policies. Our results provide high-resolution and time-series information on forest disturbance and recovery in the GKM which could support scientific decisions on forest management and sustainable utilization

Hybrid of Co₃Sn₂@Co Nanoparticles and Nitrogen-Doped Graphene as a Lithium Ion Battery Anode

A facile strategy was designed for the fabrication of hybrid of Co₃Sn₂@Co nanoparticles (NPs) and nitrogen-doped graphene (NG) sheets through a hydrothermal synthesis, followed by annealing process. Core–shell architecture of Co₃Sn₂@Co pin on NG is designed for the dual encapsulation of Co₃Sn₂ with adaptable ensembles of Co and NG to address the structural and interfacial stability concerns facing tin-based anodes. In the resulted unique architecture of Co₃Sn₂@Co–NG hybrid, the sealed cobalt cover prevents the direct exposer of Sn with electrolyte because of encapsulated structure and keeps the structural and interfacial integrity of Co₃Sn₂. However, the elastically strong, flexible and conductive NG overcoat accommodates the volume changes and therefore brings the structural and electrical stabilization of Co₃Sn₂@Co NPs. As a result, Co₃Sn₂@Co–NG hybrid exhibits extraordinary reversible capacity of 1615 mAh/g at 250 mA/g after 100 cycles with excellent capacity retention of 102%. The hybrid bears superior rate capability with reversible capacity of 793.9 mAh/g at 2500 mA/g and Coulombic efficiency nearly 100%

Comprehensive analysis of m6A modification in lipopolysaccharide-induced acute lung injury in mice

Abstract Background N6-Methyladenosine (m6A) methylation is the most prevalent post-transcriptional modification in mRNA, and plays significant roles in various diseases. Nevertheless, the precise functions of m6A modification in the formation of ALI remain unclear. In this study we explore the transcriptome distribution of m6A methylation and its probable roles of in ALI. Methods Lipopolysaccharide (LPS) was utilized to establish an ALI mouse model. Real-time qPCR, Western blotting and m6A dot blot were utilized to assess m6A methylation level and the expression of m6A methylation enzymes. MeRIP-Seq and RNA-seq were utilized to explore differential m6A modifications and differentially expressed genes in ALI mice. The hub genes and enriched pathways were assessed by Real-time qPCR and Western blotting. Results Our findings showed that overall m6A methylation level was increased in ALI mice lung tissues, accompanied by lower levels of METTL3 and FTO. Notably, the protein expression of these methylases were different in various cells. There were 772 differently expressed m6A peaks in ALI as compared to the control group, with 316 being hypermethylated and 456 being hypomethylated. GO and KEGG analyses demonstrated these differentially methylated genes were associated with the calcium signaling pathway and cAMP signaling pathway. Furthermore, we identified 50 genes with distinct m6A peaks and mRNA expressions by combined analysis of MeRIP-Seq and RNA-Seq. KEGG analysis also demonstrated that these overlapped genes were closely associated with the calcium signaling pathway, cGMP-PKG signaling pathway, etc. Besides, Western blotting results demonstrated that the protein expression of Fibronectin leucine-rich transmembrane protein 3 (Flrt3) as well as the calcium signaling pathway and cGMP-PKG signaling pathway, increased significantly after ALI. Conclusions m6A modification was paramount in the pathogenesis of ALI, and provided a foundation for the further investigation in the prevention and treatment of ALI

HDAC3 promotes macrophage pyroptosis via regulating histone deacetylation in acute lung injury

Summary: Activated inflammation and pyroptosis in macrophage are closely associated with acute lung injury (ALI). Histone deacetylase 3 (HDAC3) serves as an important enzyme that could repress gene expression by mediating chromatin remodeling. In this study, we found that HDAC3 was highly expressed in lung tissues of lipopolysaccharide (LPS)-treated mice. Lung tissues from macrophage HDAC3-deficient mice stimulated with LPS showed alleviative lung pathological injury and inflammatory response. HDAC3 silencing significantly blocked the activation of cyclic GMP-AMP synthase (cGAS)/stimulator of interferon genes (STING) pathway in LPS-induced macrophage. LPS could recruit HDAC3 and H3K9Ac to the miR-4767 gene promoter, which repressed the expression of miR-4767 to promote the expression of cGAS. Taken together, our findings demonstrated that HDAC3 played a pivotal role in mediating pyroptosis in macrophage and ALI by activating cGAS/STING pathway through its histone deacetylation function. Targeting HDAC3 in macrophage may provide a new therapeutic target for the prevention of LPS-induced ALI