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Mitochondrial dysfunction has been implicated in the development of heart failure. Oxidative metabolism in mitochondria is the main energy source of the heart, and the inability to generate and transfer energy has long been considered the primary mechanism linking mitochondrial dysfunction and contractile failure. However, the role of mitochondria in heart failure is now increasingly recognized to be beyond that of a failed power plant. In this Review, we summarize recent evidence demonstrating vicious cycles of pathophysiological mechanisms during the pathological remodeling of the heart that drive mitochondrial contributions from being compensatory to being a suicide mission. These mechanisms include bottlenecks of metabolic flux, redox imbalance, protein modification, ROS-induced ROS generation, impaired mitochondrial Ca2+ homeostasis, and inflammation. The interpretation of these findings will lead us to novel avenues for disease mechanisms and therapy.

Sepsis is a systemic inflammatory response syndrome caused by infection, resulting in organ dysfunction. Sepsis‐induced acute kidney injury (AKI) is one of the most common potential complications. Increasing reports have shown that M1 and M2 macrophages both take part in the progress of AKI by influencing the level of inflammatory factors and the cell death, including pyroptosis. However, whether M1 and M2 macrophages regulate AKI by secreting exosome remains unknown. In the present study, we isolated the exosomes from M1 and M2 macrophages and used Western blot and enzyme‐linked immunosorbent assay (ELISA) to investigate the effect of M1 and M2 exosomes on cell pyroptosis. miRNA sequencing was used to identify the different miRNA in M1 and M2 exosomes. Luciferase reporter assay was used to verify the target gene of miRNA. We confirmed that exosomes excreted by macrophages regulated cell pyroptosis in vitro by using Western blot and ELISA. miRNA sequencing revealed the differentially expressed level of miRNAs in M1 and M2 exosomes, among which miR‐93‐5p was involved in the regulation of pyroptosis. By using bioinformatics predictions and luciferase reporter assay, we found that thioredoxin–interacting protein (TXNIP) was a direct target of miR‐93‐5p. Further in vitro and in vivo experiments indicated that exosomal miR‐93‐5p regulated the TXNIP directly to influence the pyroptosis in renal epithelial cells, which explained the functional difference between different phenotypes of macrophages. This study might provide new targets for the treatment of sepsis‐induced AKI.

Haematopoietic stresses mobilize haematopoietic stem cells (HSCs) from the bone marrow to the spleen and induce extramedullary haematopoiesis (EMH). However, the cellular nature of the EMH niche is unknown. Here we assessed the sources of the key niche factors, SCF (also known as KITL) and CXCL12, in the mouse spleen after EMH induction by myeloablation, blood loss, or pregnancy. In each case, Scf was expressed by endothelial cells and Tcf21 + stromal cells, primarily around sinusoids in the red pulp, while Cxcl12 was expressed by a subset of Tcf21 + stromal cells. EMH induction markedly expanded the Scf -expressing endothelial cells and stromal cells by inducing proliferation. Most splenic HSCs were adjacent to Tcf21 + stromal cells in red pulp. Conditional deletion of Scf from spleen endothelial cells, or of Scf or Cxcl12 from Tcf21 + stromal cells, severely reduced spleen EMH and reduced blood cell counts without affecting bone marrow haematopoiesis. Endothelial cells and Tcf21 + stromal cells thus create a perisinusoidal EMH niche in the spleen, which is necessary for the physiological response to diverse haematopoietic stresses. Haematopoietic stem cells normally reside in a bone marrow niche but they are recruited to the spleen after physiological stresses; here, endothelial cells and stromal cells around sinusoidal blood vessels of the spleen are shown to secrete key niche factors to support this process. Spleen haematopoetic niche characterized In normal conditions, most haematopoietic stem cells (HSCs) are found in a bone marrow niche where haematopoesis occurs, but during physiological stress they are recruited to the spleen to engage in extramedullary haematopoiesis. This study demonstrates that the extramedullary hematopoiesis niche in the mouse spleen is created by endothelial cells and supported by key niche factors secreted by stromal cells around sinusoidal blood vessels of the spleen.

7XXX series aluminum alloys (Al 7XXX alloys) are widely used in bearing components, such as aircraft frame, spars and stringers, for their high specific strength, high specific stiffness, high toughness, excellent processing, and welding performance. Therefore, Al 7XXX alloys are the most important structural materials in aviation. In this present review, the development tendency and the main applications of Al 7XXX alloys for aircraft structures are introduced, and the existing problems are simply discussed. Also, the heat treatment processes for improving the properties are compared and analyzed. It is the most important measures that optimizing alloy composition and improving heat treatment process are to enhance the comprehensive properties of Al 7XXX alloys. Among the method, solid solution, quenching, and aging of Al 7XXX alloys are the most significant. We introduce the effects of the three methods on the properties, and forecast the development direction of the properties, compositions, and heat treatments and the solution to the corrosion prediction problem for the next generation of Al 7XXX alloys for aircraft structures. The next generation of Al 7XXX alloys should be higher strength, higher toughness, higher damage tolerance, higher hardenability, and better corrosion resistance. It is urgent requirements to develop or invent new heat treatment regime. We should construct a novel corrosion prediction model for Al 7XXX alloys via confirming the surface corrosion environments and selecting the accurate and reliable electrochemical measurements.

Background Protein-protein interactions (PPIs) are critical for many biological processes. It is therefore important to develop accurate high-throughput methods for identifying PPI to better understand protein function, disease occurrence, and therapy design. Though various computational methods for predicting PPI have been developed, their robustness for prediction with external datasets is unknown. Deep-learning algorithms have achieved successful results in diverse areas, but their effectiveness for PPI prediction has not been tested. Results We used a stacked autoencoder, a type of deep-learning algorithm, to study the sequence-based PPI prediction. The best model achieved an average accuracy of 97.19% with 10-fold cross-validation. The prediction accuracies for various external datasets ranged from 87.99% to 99.21%, which are superior to those achieved with previous methods. Conclusions To our knowledge, this research is the first to apply a deep-learning algorithm to sequence-based PPI prediction, and the results demonstrate its potential in this field.

Dynamic control of multi-photon upconversion with rich and tunable emission colors is stimulating extensive interest in both fundamental research and frontier applications of lanthanide based materials. However, manipulating photochromic upconversion towards color-switchable emissions of a single lanthanide emitter is still challenging. Here, we report a conceptual model to realize the spatiotemporal control of upconversion dynamics and photochromic evolution of Er 3+ through interfacial energy transfer (IET) in a core-shell nanostructure. The design of Yb sublattice sensitization interlayer, instead of regular Yb 3+ doping, is able to raise the absorption capability of excitation energy and enhance the upconversion. We find that a nanoscale spatial manipulation of interfacial interactions between Er and Yb sublattices can further contribute to upconversion. Moreover, the red/green color-switchable upconversion of Er 3+ is achieved through using the temporal modulation ways of non-steady-state excitation and time-gating technique. Our results allow for versatile designs and dynamic management of emission colors from luminescent materials and provide more chances for their frontier photonic applications such as optical anti-counterfeiting and speed monitoring. Achieving spatiotemporal control of photochromic upconversion from a single lanthanide emitter remains challenging. Here, the authors present a conceptual model enabling such control of Er 3+ photochromic upconversion via interfacial energy transfer in a core-shell nanostructure.

Quantitative research on the impact weight and impact of regional heterogeneity of urban spatial structure elements on carbon emissions efficiency can provide a scientific basis and practical guidance for low-carbon and sustainable urban development. This study uses the megacity of Chengdu as an example to measure and analyze the spatial carbon emission efficiency and multidimensional spatial structure elements by building a high-resolution grid and identifying the main spatial structure elements that affect urban carbon emissions and their impact weights via the Ordinary Least Squares regression (OLS) and Geographically Weighted Regression (GWR). The spatial heterogeneity of the impact of each element is also explored. The results show that the overall carbon emission efficiency of Chengdu is high in the center and low on the sides, which is related to urban density, functional mix, land use, and traffic structure. However, the influence of each spatial structure element is different in the developed central areas, developing areas of the plain, mountainous developing areas, underdeveloped areas of the plain, and mountainous underdeveloped areas. Thus, it is appropriate to form differentiated urban planning strategies based on the characteristics of the development of each zone. The findings provide inspiration and a scientific basis for formulating policies and practice to the future low-carbon development of Chengdu, while provide a reference for other growing megacities.

Small extracellular vesicles (SEVs) are functional messengers of certain cellular niches that permit noncontact cell communications. Whether niche-specific SEVs fulfill this role in cancer is unclear. Here, we used 7 cell type-specific mouse Cre lines to conditionally knock out Vps33b in Cdh5+ or Tie2+ endothelial cells (ECs), Lepr+ BM perivascular cells, Osx+ osteoprogenitor cells, Pf4+ megakaryocytes, and Tcf21+ spleen stromal cells. We then examined the effects of reduced SEV secretion on progression of MLL-AF9-induced acute myeloid leukemia (AML), as well as normal hematopoiesis. Blocking SEV secretion from ECs, but not perivascular cells, megakaryocytes, or spleen stromal cells, markedly delayed the leukemia progression. Notably, reducing SEV production from ECs had no effect on normal hematopoiesis. Protein analysis showed that EC-derived SEVs contained a high level of ANGPTL2, which accelerated leukemia progression via binding to the LILRB2 receptor. Moreover, ANGPTL2-SEVs released from ECs were governed by VPS33B. Importantly, ANGPTL2-SEVs were also required for primary human AML cell maintenance. These findings demonstrate a role of niche-specific SEVs in cancer development and suggest targeting of ANGPTL2-SEVs from ECs as a potential strategy to interfere with certain types of AML.

Human activity recognition (HAR) has become an intensive research topic in the past decade because of the pervasive user scenarios and the overwhelming development of advanced algorithms and novel sensing approaches. Previous HAR-related sensing surveys were primarily focused on either a specific branch such as wearable sensing and video-based sensing or a full-stack presentation of both sensing and data processing techniques, resulting in weak focus on HAR-related sensing techniques. This work tries to present a thorough, in-depth survey on the state-of-the-art sensing modalities in HAR tasks to supply a solid understanding of the variant sensing principles for younger researchers of the community. First, we categorized the HAR-related sensing modalities into five classes: mechanical kinematic sensing, field-based sensing, wave-based sensing, physiological sensing, and hybrid/others. Specific sensing modalities are then presented in each category, and a thorough description of the sensing tricks and the latest related works were given. We also discussed the strengths and weaknesses of each modality across the categorization so that newcomers could have a better overview of the characteristics of each sensing modality for HAR tasks and choose the proper approaches for their specific application. Finally, we summarized the presented sensing techniques with a comparison concerning selected performance metrics and proposed a few outlooks on the future sensing techniques used for HAR tasks.

Endothelial cells and leptin receptor + (LepR + ) stromal cells are critical sources of haematopoietic stem cell (HSC) niche factors, including stem cell factor (SCF), in bone marrow. After irradiation or chemotherapy, these cells are depleted while adipocytes become abundant. We discovered that bone marrow adipocytes synthesize SCF. They arise from Adipoq -Cre/ER + progenitors, which represent ∼5% of LepR + cells, and proliferate after irradiation. Scf deletion using Adipoq -Cre/ER inhibited haematopoietic regeneration after irradiation or 5-fluorouracil treatment, depleting HSCs and reducing mouse survival. Scf from LepR + cells, but not endothelial, haematopoietic or osteoblastic cells, also promoted regeneration. In non-irradiated mice, Scf deletion using Adipoq -Cre/ER did not affect HSC frequency in long bones, which have few adipocytes, but depleted HSCs in tail vertebrae, which have abundant adipocytes. A-ZIP/F1 ‘fatless’ mice exhibited delayed haematopoietic regeneration in long bones but not in tail vertebrae, where adipocytes inhibited vascularization. Adipocytes are a niche component that promotes haematopoietic regeneration. Zhou et al. demonstrate that bone marrow adipocytes, but not intraperitoneal adipocytes, express high levels of stem cell factor (SCF), which is essential for the regeneration of haematopoietic stem cells and haematopoiesis after irradiation.