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Androgenic alopecia (AGA) is a highly prevalent form of non-scarring alopecia but lacks effective treatments. Stem cell exosomes have similar repair effects to stem cells, suffer from the drawbacks of high cost and low yield yet. Cell-derived nanovesicles acquired through mechanical extrusion exhibit favorable biomimetic properties similar to exosomes, enabling them to efficiently encapsulate substantial quantities of therapeutic proteins. In this study, we observed that JAM-A, an adhesion protein, resulted in a significantly increased the adhesion and resilience of dermal papilla cells to form snap structures against damage caused by dihydrotestosterone and macrophages, thereby facilitating the process of hair regrowth in cases of AGA. Consequently, adipose-derived stem cells were modified to overexpress JAM-A to produce engineered JAM-A overexpressing nanovesicles (JAM-AOE@NV). The incorporation of JAM-AOE@NV into a thermosensitive hydrogel matrix (JAM-AOE@NV Gel) to effectively addresses the limitations associated with the short half-life of JAM-AOE@NV, and resulted in the achievement of a sustained-release profile for JAM-AOE@NV. The physicochemical characteristics of the JAM-AOE@NV Gel were analyzed and assessed for its efficacy in promoting hair regrowth in vivo and vitro. The JAM-AOE@NV Gel, thus, presents a novel therapeutic approach and theoretical framework for promoting the treatment of low cell adhesion diseases similar to AGA.

Abstract Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have garnered extensive attention as natural product-based nanomedicines and potential drug delivery vehicles. However, the specific mechanism for regulating MSC-EVs secretion and delivery remains unclear. Here, we demonstrate that extracellular matrix (ECM) stiffness regulates the secretion and delivery of EVs by affecting MSCs' cargo sorting mechanically. Using multi-omics analysis, we found that a decrease in ECM stiffness impeded the sorting of vesicular transport-related proteins and autophagy-related lipids into MSC-EVs, impairing their secretion and subsequent uptake by macrophages. Hence, MSC-EVs with different secretion and uptake behaviors can be produced by changing the stiffness of culture substrates. This study provides new insights into MSC-EV biology and establishes a connection between MSC-EV behaviors and ECM from a biophysical perspective, providing a basis for the rational design of biomedical materials. Graphical Abstract

Starch is the main carbohydrate used in fish feed, but excess dietary starch may lead to excess fat deposition in tissues, especially liver, which can lead to health problems in farmed fish. Aaldopentose monosaccharides, such as xylose and arabinose, appear to have the potential to inhibit the glucose-based lipid synthesis pathway, although the mechanism is unclear. In the present study, rabbitfish (Siganus canaliculatus) were fed two diets with basal (BSD, 15%) and high (HSD, 25%) starch levels, and six other diets in which 1.25% 2.5% and 5% D-xylose (Diets X1, X2 and X3) or L-arabinose (Diets A1, A2 and A3) were added to the HSD by replacing corresponding starch component, respectively. After 8-week feeding experiment, the results showed the HSD reduced growth performance and increased tissue lipid deposition in rabbitfish and these negative effects were generally reversed by the addition of xylose and arabinose to HSD. Specifically, the inclusion of xylose and arabinose reduced the HSD-induced activities of enzymes related to carbohydrate metabolism, including digestion (maltase and sucrase), glycolysis (HK, PFK, PK) and the production of acetyl-CoA from pyruvate (PDH). Addition of xylose or arabinose also decreased the liver expression of genes related to lipid biosynthesis (srebp1, fas and acc), and increased liver gene expression (cpt-1, hsl and lpl) and protein levels of enzymes related to lipid catabolism. Therefore, both xylose and arabinose mitigated the negative effects of HSD on growth performance, and liver and muscle lipid contents by reducing the rate of carbohydrate digestion and metabolism, and inhibiting lipid accumulation by reducing lipid biosynthesis and increasing lipid catabolism in liver. The metabolic impacts of xylose and arabinose revealed in the present study provide further insights into the molecular mechanisms underpinning the actions of the dietary aldopentose monosaccharides in reducing excess fat deposition in tissues of fish fed HSD.

Abstract Background Chronic inflammatory pain significantly reduces the quality of life and lacks effective interventions. In recent years, human umbilical cord mesenchymal stem cells (huc-MSCs)-derived exosomes have been used to relieve neuropathic pain and other inflammatory diseases as a promising cell-free therapeutic strategy. However, the therapeutic value of huc-MSCs-derived exosomes in complete Freund's adjuvant (CFA)-induced inflammatory pain remains to be confirmed. In this study, we investigated the therapeutic effect and related mechanisms of huc-MSCs-derived exosomes in a chronic inflammatory pain model. Methods C57BL/6J male mice were used to establish a CFA-induced inflammatory pain model, and huc-MSCs-derived exosomes were intrathecally injected for 4 consecutive days. BV2 microglia cells were stimulated with lipopolysaccharide (LPS) plus adenosine triphosphate (ATP) to investigate the effect of huc-MSCs-derived exosomes on pyroptosis and autophagy. Bioinformatic analysis and rescue experiments were used to demonstrate the role of miR-146a-5p/ TRAF6 in regulating pyroptosis and autophagy. Western blotting, RT-qPCR, small interfering RNA and Yo-Pro-1 dye staining were performed to investigate the related mechanisms. Results Huc-MSCs-derived exosomes alleviated mechanical allodynia and thermal hyperalgesia in CFA-induced inflammatory pain. Furthermore, huc-MSCs-derived exosomes attenuated neuroinflammation by increasing the expression of autophagy-related proteins (LC3-II and beclin1) and inhibiting the activation of NLRP3 inflammasomes in the spinal cord dorsal horn. In vitro, NLRP3 inflammasome components (NLRP3, caspase1-p20, ASC) and gasdermin D (GSDMD-F, GSDMD-N) were inhibited in BV2 cells pretreated with huc-MSCs-derived exosomes. Western blot and Yo-Pro-1 dye staining demonstrated that 3-MA, an autophagy inhibitor, weakened the protective effect of huc-MSCs-derived exosomes on BV2 cell pyroptosis. Importantly, huc-MSCs-derived exosomes transfected with miR-146a-5p mimic promoted autophagy and inhibited BV2 cell pyroptosis. TRAF6, as a target gene of miR-146a-5p, was knocked down via small-interfering RNA, which increased pyroptosis and inhibited autophagy. Conclusion Huc-MSCs-derived exosomes attenuated inflammatory pain via miR-146a-5p/TRAF6, which increased the level of autophagy and inhibited pyroptosis. Graphical Abstract

IntroductionAvian head lice comprise a diverse group of distantly related genera of lice that exhibit a strongly convergent morphology. Due to their lack of free-living stages, their strong morphological adaptations to living on the host’s head, and the limited opportunities for transfer between hosts during mating or nesting, the lateral transmission of head lice between non-conspecific hosts may be presumed to be restricted. Despite this, many species of head lice are ostensibly host generalists. We here examine lice of the head louse genus Philopteroides Mey, 2004, from bulbuls (Passeriformes: Pycnonotidae).MethodsWe use two different methods, ParaFit and Jane, to get insights on the co-evolutionary history of Philopteroides species and their bulbul hosts. Jane was run with a variation of event costs.ResultsOur phylogenetic analysis indicate that several morphologically cryptic species can be found in this group, most of which appear to be host specific. However, co-phylogenetic analyses indicate that host-switching has been common in the history of these lice, and co-speciation events have been rarer than expected. Moreover, lowest-cost co-evolutionary reconstructions under a variety of event costs are indistinguishable from random. An expanded dataset with more Philopterus-complex lice was found to be evenly balanced between host-switching and co-speciation events.DiscussionThe transfer of avian head lice between host species is poorly understood, but evidently fairly common. Several potential routes are discussed, but direct evidence is missing. Potentially, the presence of multiple bulbul species at fruiting trees may be an important factor in this transfer. However, such transfer routes also do not explain why Philopteroides lice on bulbuls appear to be distinct from those of other hosts. Moreover, as many of the species recovered in our analysis are morphologically indistinguishable, cryptic speciation appears to be common in this group.

Stem cell-based therapy has drawn attention as an alternative option for promoting prosthetic osteointegration in osteoporosis by virtue of its unique characteristics. However, estrogen deficiency is the main mechanism of postmenopausal osteoporosis. Estrogen, as an effective antioxidant, deficienncy also results in the accumulation of reactive oxygen species (ROS) in the body, affecting the osteogenic differentiation of stem cells and the bone formation i osteoporosis. In this study, we prepared a ROS-scavenging hydrogel by crosslinking of epigallocatechin-3-gallate (EGCG), 3-acrylamido phenylboronic acid (APBA) and acrylamide. The engineered hydrogel can scavenge ROS efficiently, enabling it to be a cell carrier of bone marrow-derived mesenchymal stem cells (BMSCs) to protect delivered cells from ROS-mediated death and osteogenesis inhibition, favorably enhancing the tissue repair potential of stem cells. Further in vivo investigations seriously demonstrated that this ROS-scavenging hydrogel encapsulated with BMSCs can prominently promote osteointegration of 3D printed microporous titanium alloy prosthesis in osteoporosis, including scavenging accumulated ROS, inducing macrophages to polarize toward M2 phenotype, suppressing inflammatory cytokines expression, and improving osteogenesis related markers (e.g., ALP, Runx-2, COL-1, BSP, OCN, and OPN). This work provides a novel strategy for conquering the challenge of transplanted stem cells cannot fully function in the impaired microenvironment, and enhancing prosthetic osteointegration in osteoporosis.

Physical cues in the extracellular microenvironment regulate cancer cell metastasis. Functional microRNA (miRNA) carried by cancer derived exosomes play a critical role in extracellular communication between cells and the extracellular microenvironment. However, little is known about the role of exosomes loaded miRNAs in the mechanical force transmission between cancer cells and extracellular microenvironment. Herein, our results suggest that stiff extracellular matrix (ECM) induced exosomes promote cancer cell migration. The ECM mechanical force regulated the exosome miRNA cargo of prostate cancer cells. Exosome miRNAs regulated by the ECM mechanical force modulated cancer cell metastasis by regulating cell motility, ECM remodeling and the interaction between cancer cells and nerves. Focal adhesion kinase mediated-ECM mechanical force regulated the intracellular miRNA expression, and F-actin mediate-ECM mechanical force regulated miRNA packaging into exosomes. The above results demonstrated that the exosome miRNA cargo promoted cancer metastasis by transmitting the ECM mechanical force. The ECM mechanical force may play multiple roles in maintaining the microenvironment of cancer metastasis through the exosome miRNA cargo.

Biphasic calcium phosphate (BCP) containing hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) is considered the gold standard for bone repair. However, the complex synthesis of BCP restricts the wide application of BCP. In the preliminary work, we proved that the HA/β-TCP BCP ceramic material extracted from fishery waste had a good prospect as a bone replacement graft material for filling bone defects. This study aimed to explore the osteogenesis effect of BCP material derived from butterfish bones in vivo and in vitro. After loading human bone marrow mesenchymal stem cells (hBMSCs) with materials, we used scanning electron microscopy to observe cell adhesion and survival. Western blot analysis was used to detect osteogenic expression in vitro. Micro-computed tomography and hematoxylin–eosin staining were used to detect bone regeneration and material degradation rate in the rat femoral defect model. The results showed that hBMSCs grew well and adhered closely to the material. In vitro, the expression levels of bone formation–related markers ALP and Runx-2 of butterfish bones calcined at 900°C were generally higher than those in the other groups. Notably, in vivo, the osteogenesis ability of butterfish bones calcined at 900°C was almost comparable to that of the most commonly used Bio-Oss in clinical practice and was significantly better than that in the other groups. In summary, the BCP ceramic material derived from butterfish bones had good biocompatibility, osteoconductivity, and osteoinductivity, and had a good application prospect in the field of bone graft substitutes.

Zirconium alloys, which are widely used as cladding materials in nuclear reactors, are prone to react with oxygen (O). Furthermore, the ω-Zr in zirconium alloys can significantly increase the strength and hardness of these alloys, but there is a lack of reports on the behavior of oxygen in ω-Zr in the current literature. To investigate their interactions, we have studied the behavior of O in ω-Zr using the first-principles approach. In this work, we examined the effects of vacancy and alloying elements (Nb, Sn) on the behavior of O in ω-Zr. The results show that O with a formation energy of −5.96 eV preferentially occupies an octahedral interstitial position in ω-Zr. A vacancy reduces the formation energy of O in a tetrahedral interstitial position in ω-Zr. Nb and Sn decrease the formation energy of O in the octahedral interstitial position by 6.16 eV and 5.08 eV. Vacancy effectively reduces the diffusion barrier of O around it, which facilitates the diffusion of O in ω-Zr. Nb and Sn preferentially occupy the 1b and 2d substitution sites in ω-Zr, respectively. Nb makes the diffusion barrier of O in ω-Zr lower and promotes the diffusion of O in ω-Zr. Moreover, Sn makes the diffusion of O around Sn difficult. It was further found that O is less prone to form clusters in ω-Zr and tends to independently occupy interstitial positions in ω-Zr. In particular, a single vacancy would make the binding energy between O atoms to be further reduced.

Abstract Wearable and portable mobile phones play a critical role in the market, and one of the key technologies is the flexible electrode with high specific capacity and excellent mechanical flexibility. Herein, a wire-in-wire TiO2/C nanofibers (TiO2 ww/CN) film is synthesized via electrospinning with selenium as a structural inducer. The interconnected carbon network and unique wire-in-wire nanostructure cannot only improve electronic conductivity and induce effective charge transports, but also bring a superior mechanic flexibility. Ultimately, TiO2 ww/CN film shows outstanding electrochemical performance as free-standing electrodes in Li/K ion batteries. It shows a discharge capacity as high as 303 mAh g−1 at 5 A g−1 after 6000 cycles in Li half-cells, and the unique structure is well-reserved after long-term cycling. Moreover, even TiO2 has a large diffusion barrier of K+, TiO2 ww/CN film demonstrates excellent performance (259 mAh g−1 at 0.05 A g−1 after 1000 cycles) in K half-cells owing to extraordinary pseudocapacitive contribution. The Li/K full cells consisted of TiO2 ww/CN film anode and LiFePO4/Perylene-3,4,9,10-tetracarboxylic dianhydride cathode possess outstanding cycling stability and demonstrate practical application from lighting at least 19 LEDs. It is, therefore, expected that this material will find broad applications in portable and wearable Li/K-ion batteries.

A hydrogel system loaded with mesenchymal stem cell–derived exosome (MSC-Exos) is an attractive new tool for tissue regeneration. However, the effect of the stiffness of exosome-loaded hydrogels on tissue regeneration is unclear. Here, the role of exosome-loaded hydrogel stiffness, during the regeneration of injured nerves, was assessed in vivo. The results showed that the photocrosslinkable hyaluronic acid methacrylate hydrogel stiffness plays an important role in repairing nerve injury. Compared with the stiff hydrogels loaded with exosomes, soft hydrogels loaded with exosomes showed better repair of injured peripheral nerves. The soft hydrogel promoted nerve repair by quickly releasing exosomes to inhibit the infiltration of macrophages and the expression of the proinflammatory factors IL-1β and TNF-α in injured nerves. Our work revealed that exosome-loaded hydrogel stiffness plays an important role in tissue regeneration by regulating exosome release behavior and provided important clues for the clinical application of biological scaffold materials.

Cell lineage reprogramming is the main approach for cancer cells to acquire drug resistance and escape targeted therapy. The use of potent targeted therapies in cancers has led to the development of highly aggressive carcinoma, including neuroendocrine prostate cancer (NEPC). Although metabolic reprogramming has been reported to be essential for tumor growth and energy production, the relationship between metabolic reprogramming and lineage differentiation which can cause hormone therapy resistance has never been reported in prostate cancer (PCa). Moreover, as there is still no efficient therapy for NEPC, it is urgent to reverse this lineage differentiation during the hormone therapy. Here for the first time, we used in vitro and in vivo human PCa models to study the effect of metabolic reprogramming on the lineage differentiation from the androgen receptor (AR)–dependent adenocarcinoma to AR-independent NEPC. This lineage differentiation leads to antiandrogen drug resistance and tumor development. This phenotype is enabled by the loss of mitochondrial pyruvate carrier (MPC), the gate for mitochondrial pyruvate influx, and can be reversed by MPC overexpression. Morphologic and cellular studies also demonstrate that the pyruvate kinase M2 (PKM2) involved epithelium–mesenchymal transition process mediated this lineage alteration. Its inhibition is a potential treatment for MPC-lo tumors. All of these results suggest that metabolic rewiring can act as a starter for increased cellular plasticity which leads to antiandrogen therapy resistance through lineage differentiation. This study provides us with a potent treatment target for therapy-induced, enzalutamide-resistant NE-like prostate cancer.

Loading human umbilical mesenchymal stem cell (hUMSC) derived exosomes onto hydrogel scaffolds is a strategy for rapid wound healing. The clinical application of exosomes is hindered by low production, and exosome mimetics could be substituted for exosomes. Here, the therapeutic effects of exosome-loaded hydrogels and exosome mimetic-loaded hydrogels on wounds are evaluated. Our results revealed that exosome mimetic-loaded hydrogels promote wound healing more efficiently than exosome-loaded hydrogels. Exosome mimetics can promote the proliferation and migration of dermal fibroblasts (hDF-a) cells in vitro. To investigate how exosome mimetics play a role, proteomics analysis was applied, and the obtained results suggested that exosome mimetics significantly enrich mitochondrial-derived oxidative phosphorylation-related proteins in comparison to exosomes. Overall, our work envisages the emerging potential of exosome mimetics, which take the advantage of exosomes and can be promising candidates for exosomes. It also suggests that hUMSC-derived exosome mimetic-loaded hydrogels have remarkable prospects for clinical application.

The modulation of single-atom catalyst properties for industrial applications remains challenging. Here, authors use strain engineering to amplify the synergistic effect between MoS2’s sulphur vacancies and single-atom Ru sites and accelerate H2 evolution electrocatalysis.

The oxidation corrosion is a crucial challenge for zirconium (Zr) alloys as cladding materials in fission power reactors. In the present study, a first-principles approach is employed for understanding behaviors of oxygen adsorbed on the Zr (101-1) surface. It is found that the Zr substrate is reactive to O species. Electrons in the 4d band of the metallic substrate tend to migrate to antibonding orbitals of the adsorbed O2 molecule, leading to breaking the O-O bond and releasing energy. Several diffusion paths for an adsorbed O atom migrating to the subsurface interstitial site are proposed. It is found that the lowest diffusion barrier is only 0.08 eV. Therefore, it can be inferred that the Zr (101-1) surface suffers fast oxidation kinetics.

Xe and Kr gases produced during the use of uranium dioxide (UO2)-fuelled reactors can easily form bubbles, resulting in fuel swelling or performance degradation. Therefore, it is important to understand the influence of point defects on the behaviour of Xe and Kr gases in UO2. In this work, the effects of point defects on the behavioural characteristics of Xe/Kr clusters in UO2 have been systematically studied using molecular dynamics. The results show that Xe and Kr clusters occupy vacancies as nucleation points by squeezing U atoms out of the lattice, and the existence of vacancies makes the clusters more stable. The diffusion of interstitial Xe/Kr atoms and clusters in UO2 is also investigated. It is found that the activation energy is ~2 eV and that the diffusion of the interstitial atoms is very difficult. Xe and Kr bubbles form at high temperatures. The more interstitial Xe/Kr atoms or vacancies in the system, the easier the clusters form.

Intergranular corrosion is the most common corrosion phenomenon in Fe-based alloys. To better understand the mechanism of intergranular corrosion, the influence of grain boundaries on Fe-H2O interfacial corrosion was studied using molecular dynamics simulation based on a new Fe-H2O reaction force field potential. It is found that the corrosion rate at the polycrystalline grain boundary is significantly faster than that of twin crystals and single crystals. By the analysis of stress, it can be found that the stress at the polycrystalline grain boundary and the sigma5 twin grain boundary decreases sharply during the corrosion process. We believe that the extreme stress released at the grain boundary will promote the dissolution of Fe atoms. The formation of vacancies on the Fe matrix surface will accelerate the diffusion of oxygen atoms. This leads to the occurrence of intergranular corrosion.

To ensure the safety and efficient operation of nuclear reactors, it is imperative to understand the effects of various dopants (Ti, Th, and Zr) on the solubility of the fission product Xe in UO2. In this study, Hubbard corrected density functional theory (DFT + U) and occupation matrix control were used to investigate the bulk and defect properties of UO2. The results show that the UO2-Ti system is more favorable for Xe dissolution in vacancies, whereas the UO2-Th system has little effect on the dissolution of Xe atoms. Th, Zr, and Ti inhibit the aggregation of Xe clusters, and Ti is the least favorable for the nucleation and growth of Xe clusters.

In this study, we investigated the behavior of xenon (Xe) bubbles in uranium dioxide (UO2) grain boundaries using molecular dynamics simulations and compared it to that in the UO2 bulk. The results show that the formation energy of Xe clusters at the Σ5 grain boundaries (GBs) is much lower than in the bulk. The diffusion activation energy of a single interstitial Xe atom at the GBs was approximately 1 eV lower than that in the bulk. Furthermore, the nucleation and growth of Xe bubbles in the Σ5 GBs at 1000 and 2000 K were simulated. The volume and pressure of bubbles with different numbers of Xe atoms were simulated. The bubble pressure dropped with increasing temperature at low Xe concentrations, whereas the volume increased. The radial distribution function was computed to explore the configuration evolution of Xe bubbles. The bubble structures in the GB and bulk material at the same temperature were also compared. Xe atoms were more regular in the bulk, whereas multiple Xe atoms formed a planar structure at the GBs.

The reaction behaviors of gas molecules on metal surface will contribute to understanding the oxidation process of metal and preventing the metal surface from corrosion. In this work, the interactions between nitrogen oxides and α-uranium (α-U) surface have been studied using density-functional theory calculations. Based on thermodynamics analysis, it is found that nitric oxide (NO) can be easily decomposed into N and O atoms, and then be adsorbed on the α-U surface; Pre-adsorption N can facilitate the dissociation of NO molecule. Nitrous oxide (N2O) also tends to dissociate into the compounds of N2 and O on U surface. The N2O dissociation on α-U surface includes three steps: N2O physical adsorption, partial dissociation into N2 molecule and O atom, and then N2 adsorption or N2 dissociation. Moreover, N2 can be formed by the N2O dissociation or the reaction of NO and N. These results can provide a sound explanation for the available experimental results.

Novel positively charged nanofiltration membranes were facilely prepared by polydopamine (PDA) deposition followed by crosslinking on the polyethersulfone (PES) ultrafiltration (UF) membrane substrate. Specifically, small molecules DMAPA and 1,3-dibromopropane were separately selected as the bridge agent and crosslinking agent, which can not only realize the moderate crosslinking and densification of the loose structure of the PDA layer, but also further improve the hydrophilicity and positive charges of the PDA layer. Under the optimized conditions of DMAPA concentration (2 g/L), 1,3-dibromopropane concentration (10 wt%) and reaction time (9 h), the composite membrane had the surface pore size as low as 1.1 nm, water contact angle as low as 35.1° and zeta potential as high as +63.8 mV at pH = 6. As a result, the optimized positively charged NF membrane (M3) showed an outstanding permeance up to 15.7 L m−2 h−1 bar−1 while maintaining a high rejection above 95% for MgCl2. Meanwhile, M3 also showed good environmental adaptability when facing complex feeding or operating conditions. This work provided new situation in the design and construction of positive charged NF membranes for high efficiency cation separation.

Abstract The physical cues in the extracellular environment play important roles in cancer cell metastasis. However, how metastatic cancer cells respond to the diverse mechanical environments of metastatic sites is not fully understood. Here, substrates with different mechanical properties are prepared to simulate the extracellular mechanical environment of various human tissues. The prostate cancer (PC) cells derived from different cancer metastasis sites show heterogeneity in mechanical response. This heterogeneity mediates two distinct metastasis patterns. High stiffness promotes individual cell migration and proliferation by inducing Yes‐associated protein and tafazzin (YAP/TAZ) nuclear localization in bone metastasis‐derived cells, whereas low stiffness promotes cell migration and proliferation by inducing lymphatic metastasis‐derived cells to form clusters characterized by high expression of CD44. The different metastasis patterns induced by the mechanical properties of the extracellular environment are crucial in the development of PC.

Large prefabricated flaps often suffer from necrosis or poor healing due to a lack of new blood vessels and related factors that promote angiogenesis. The innovative use of adipose-derived stem cell exosomes (ADSC-Exo) resolves the problem of vascularization of prefabricated flaps. We analyzed the differential microRNA (miRNA) expression in ADSC-Exo using next-generation sequencing (NGS) technology to explore their potential mechanisms in promoting vascularization. We observed that ADSC-Exo could significantly promote the vascularization of artificial dermis prefabricated flaps compared with human foreskin fibroblast exosomes. NGS indicated that there were some differentially expressed miRNAs in both exosomes. Bioinformatics analysis suggested that significantly upregulated hsa-miR-760 and significantly downregulated hsa-miR-423-3p in ADSC-Exo could regulate the expression of the ITGA5 and HDAC5 genes, respectively, to promote the vascularization of skin flaps. In summary, ADSC-Exo can promote skin-flap vascularization, and thereby resolve the problem of insufficient neovascularization of artificial dermis prefabricated flaps, thus expanding the application of prefabricated skin-flap transplantation.

Liquid Na is widely used as the heat transfer medium in high-temperature heat pipes based on Mo-Re alloys. In this study, ab initio molecular dynamics are employed in order to understand the interactions between the Na solvent and Mo or Re solute in the liquid phase. Both the temperature and concentration effects on the clustering and diffusion behaviors of solute atoms are investigated. It is found that Mo2 and Re2 dimers can be stabilized in liquid Na, and the higher temperature leads to a stronger binding force. Pure Re and Mo-Re mixed solutes can form tetramers at the highest concentration. However, for the pure Mo solute, Mo4 is not observed. The diffusivities of a single solute atom and clusters are calculated. It is found that the Mo species diffuse faster than the Re species, and the diffusivity decreases as the cluster size increases.

Molybdenum-rhenium alloys are usually used as the wall materials for high-temperature heat pipes using liquid sodium as heat-transfer medium. The corrosion of Mo in liquid Na is a key challenge for heat pipes. In addition, oxygen impurity also plays an important role in affecting the alloy resistance to Na liquid. In this article, the adsorption and diffusion behaviors of Na atom on Mo (110) surface are theoretically studied using first-principles approach, and the effects of alloy Re and impurity O atoms are investigated. The result shows that the Re alloy atom can strengthen the attractive interactions between Na/O and the Mo substrate, and the existence of Na or O atom on the Mo surface can slower down the Na diffusion by increasing diffusion barrier. The surface vacancy formation energy is also calculated. For the Mo (110) surface, the Na/O co-adsorption can lead to a low vacancy formation energy of 0.47 eV, which indicates the dissolution of Mo is a potential corrosion mechanism in the liquid Na environment with O impurities. It is worth noting that Re substitution atom can protect the Mo surface by increasing the vacancy formation energy to 1.06 eV.

Seawater (SW) immersion can increase the damage of skin wounds and produce refractory wounds. However, few studies have been conducted to investigate the mechanisms of SW immersion on skin wounds. In our current study, we investigated the effect of human adipose-derived stem cells (hADSCs) on the repair of SW-treated full-thickness skin wounds and the underlying mechanisms. The results showed that SW immersion could reduce the expression of EGF and suppress the activation of the MEK/ERK signaling pathway. At the same time, the proliferation and migration of skin stem cells were inhibited by SW immersion, resulting in delayed wound healing. However, hADSCs significantly accelerated the healing of SW-immersed skin wounds by promoting cell proliferation and migration through the aforementioned mechanisms. Our results indicate a role for hADSCs in the repair of seawater-immersed skin wounds and suggest a potential novel treatment strategy for seawater-immersed wound healing.

In this work, hydrogenated bisphenol A (HBPA) based dinitro mixed isomers (1a′ and 1a) were synthesized and separated via vacuum distillation under the monitor of DSC and 1H NMR. Corresponding diamines (2a′ and 2a) were separately polycondensed with five commercial dianhydrides via a two-step thermal imidization to obtain PI-(1′-5′) and PI-(1-5). All the polyimides could afford flexible, tough, and transparent films, and most of them were readily soluble not only in common polar solvents like DMAc, but also in low boiling point solvents such as chloroform. 1H NMR spectra of the polyimides demonstrated that HBPA moiety showed no conformation changes during the preparation of polymers. For a given dianhydride, PI-(1-5) exhibited better thermal stability than that of PI-(1′-5′), this can be attributed that the equatorial, equatorial C−O in PI-(1-5) promoted denser and more regular molecular chain stacking, as can be evidenced by the WAXD and geometric optimization results. Additionally, when the dianhydride was ODPA, BPADA or 6FDA, no apparent difference was found in either the transmittance or solubility between two series of polyimides, which could be attributed that twisted and flexible ether linkages, as well as bulky substituents, led to the “already weakened” inter- and intramolecular CT interaction and cohesive force. However, when it came to rigid and stiff dianhydride, e.g., BPDA, PI-3′ took an obvious advantage over PI-3 in transmittance and solubility, which was possibly owed to the larger molecular chain d-spacing imparted by equatorial, axial C−O. An overall investigation of PI-(1′-5′) and PI-(1-5) on aspects of thermal, mechanical, morphological, soluble and optical performance values was carried out, and the conformation effects of HBPA isomers on the properties of two series of polyimides were discussed in detail.