Inhibiting SHP2 reduces glycolysis, promotes microglial M1 polarization, and alleviates secondary inflammation following spinal cord injury in a mouse model.

JOURNAL/nrgr/04.03/01300535-202503000-00030/figure1/v/2024-06-17T092413Z/r/image-tiff Reducing the secondary inflammatory response, which is partly mediated by microglia, is a key focus in the treatment of spinal cord injury. Src homology 2-containing protein tyrosine phosphatase 2 (SHP2), encoded by PTPN11, is widely expressed in the human body and plays a role in inflammation through various mechanisms. Therefore, SHP2 is considered a potential target for the treatment of inflammation-related diseases. However, its role in secondary inflammation after spinal cord injury remains unclear. In this study, SHP2 was found to be abundantly expressed in microglia at the site of spinal cord injury. Inhibition of SHP2 expression using siRNA and SHP2 inhibitors attenuated the microglial inflammatory response in an in vitro lipopolysaccharide-induced model of inflammation. Notably, after treatment with SHP2 inhibitors, mice with spinal cord injury exhibited significantly improved hind limb locomotor function and reduced residual urine volume in the bladder. Subsequent in vitro experiments showed that, in microglia stimulated with lipopolysaccharide, inhibiting SHP2 expression promoted M2 polarization and inhibited M1 polarization. Finally, a co-culture experiment was conducted to assess the effect of microglia treated with SHP2 inhibitors on neuronal cells. The results demonstrated that inflammatory factors produced by microglia promoted neuronal apoptosis, while inhibiting SHP2 expression mitigated these effects. Collectively, our findings suggest that SHP2 enhances secondary inflammation and neuronal damage subsequent to spinal cord injury by modulating microglial phenotype. Therefore, inhibiting SHP2 alleviates the inflammatory response in mice with spinal cord injury and promotes functional recovery postinjury.

Disease severity drives risk of venous thrombotic events in women with sickle cell disease in a single-center retrospective study.

Background: Estrogen-containing hormonal contraception (HC) is a well-established risk factor for venous thromboembolism (VTE). Women with sickle cell disease (SCD) also have an increased risk of VTE. However, it is unknown if exposure to HC exacerbates the risk of VTE in women with SCD. Objectives: Assess the impact of HC on VTE risk in women with SCD and explore additional risk factors contributing to VTE development. Methods: We analyzed a retrospective cohort of women of reproductive age (15-49 years) with SCD at the University of North Carolina from 2010 to 2022. Results: We identified 370 women with SCD, and 93 (25.1%) had a history of VTE. Among 219 women exposed to HC, 38 of 184 (20.6%) had a VTE while actively using HC, whereas 20 of 151 (13.2%) women never exposed to HC had a VTE. Of the patients exposed to HC, 64 of 184 (34.7%) were on estrogen-containing HC, with 120 of 184 (65.3%) using progestin-only formulations. Cox regression analysis found that progestin-only formulations increased VTE risk (hazard ratio: 2.03; 95% CI: 1.107-3.726, P < .05). However, when accounting for disease severity, the association between progestin-only treatment and VTE risk was not significant. Indeed, a nuanced analysis revealed that both severe (odds ratio: 11.79; 95% CI: 5.14-27.06; P < .001) and moderate (odds ratio: 4.37; 95% CI: 1.77-10.76; P = .001) disease increased risk compared with mild disease. Neither genotype nor hydroxyurea use influenced VTE risk. Conclusion: Overall, we found that increased thrombotic risk is more likely influenced by disease status than HC exposure and should play a role in shared decision-making with patients.

Unlocking the Siderophore Biosynthesis Pathway and Its Biological Functions in the Fungal Insect Pathogen Beauveria bassiana.

Siderophores are small molecule iron chelators. The entomopathogenic fungus Beauveria bassiana produces a plethora of siderophores under iron-limiting conditions. In this study, a siderophore biosynthesis pathway, akin to the general pathway observed in filamentous fungi, was revealed in B. bassiana. Among the siderophore biosynthesis genes (SID), BbSidA was required for the production of most siderophores, and the SidC and SidD biosynthesis gene clusters were indispensable for the production of ferricrocin and fusarinine C, respectively. Biosynthesis genes play various roles in siderophore production, vegetative growth, stress resistance, development, and virulence, in which BbSidA plays the most important role. Accordingly, B. bassiana employs a cocktail of siderophores for iron metabolism, which is essential for fungal physiology and host interactions. This study provides the initial network for the genetic modification of siderophore biosynthesis, which not only aims to improve the efficacy of biocontrol agents but also ensures the efficient production of siderophores.

The expression pattern of Wnt6, Wnt10A, and HOXA13 during regenerating tails of Gekko Japonicus.

Wnt signal is crucial to correctly regenerate tissues along the original axis in many animals. Lizards are able to regenerate their tails spontaneously, while the anterior-posterior axis information required for the successful regeneration is still elusive. In this study, we investigated the expression pattern of Wnt ligands and HOX genes during regeneration. The results of in situ hybridization revealed that Wnt6 and Wnt10A mRNA levels are higher in wound epithelium (WE) than that in blastema during regeneration. In addition, we showed that Wnt agonist positively regulated the expression of HOXA13 in cultured blastema cells, while did not show similar effect on that of HOXB13, HOXC13 and HOXD13. Finally, we found that HOXA13 showed a gradient level along the anterior-posterior axis of regenerated blastema, with higher level at the caudal end. These data proposed that Wnt6, Wnt10A and HOXA13 might play an important role in establishing distal position for regeneration.

AI-Powered Mining of Highly Customized and Superior ESIPT-Based Fluorescent Probes.

Excited-state intramolecular proton transfer (ESIPT) has attracted great attention in fluorescent sensors and luminescent materials due to its unique photobiological and photochemical features. However, the current structures are far from meeting the specific demands for ESIPT molecules in different scenarios; the try-and-error development method is labor-intensive and costly. Therefore, it is imperative to devise novel approaches for the exploration of promising ESIPT fluorophores. This research proposes an artificial intelligence approach aiming at exploring ESIPT molecules efficiently. The first high-quality ESIPT dataset and a multi-level prediction system are constructed that realized accurate identification of ESIPT molecules from a large number of compounds under a stepwise distinguishing from conventional molecules to fluorescent molecules and then to ESIPT molecules. Furthermore, key structural features that contributed to ESIPT are revealed by using the SHapley Additive exPlanations (SHAP) method. Then three strategies are proposed to ensure the ESIPT process while keeping good safety, pharmacokinetic properties, and novel structures. With these strategies, >700 previously unreported ESIPT molecules are screened from a large pool of 570 000 compounds. The ESIPT process and biosafety of optimal molecules are successfully validated by quantitative calculation and experiment. This novel approach is expected to bring a new paradigm for exploring ideal ESIPT molecules.

Mst1/Hippo signaling pathway drives isoproterenol-induced inflammatory heart remodeling.

Isoproterenol (ISO) administration is a well-established model for inducing myocardial injury, replicating key features of human myocardial infarction (MI). The ensuing inflammatory response plays a pivotal role in the progression of adverse cardiac remodeling, characterized by myocardial dysfunction, fibrosis, and hypertrophy. The Mst1/Hippo signaling pathway, a critical regulator of cellular processes, has emerged as a potential therapeutic target in cardiovascular diseases. This study investigates the role of Mst1 in ISO-induced myocardial injury and explores its underlying mechanisms. Our findings demonstrate that Mst1 ablation in cardiomyocytes attenuates ISO-induced cardiac dysfunction, preserving cardiomyocyte viability and function. Mechanistically, Mst1 deletion inhibits cardiomyocyte apoptosis, oxidative stress, and calcium overload, key contributors to myocardial injury. Furthermore, Mst1 ablation mitigates endoplasmic reticulum (ER) stress and mitochondrial fission, both of which are implicated in ISO-mediated cardiac damage. Additionally, Mst1 plays a crucial role in modulating the inflammatory response following ISO treatment, as its deletion suppresses pro-inflammatory cytokine expression and neutrophil infiltration. To further investigate the molecular mechanisms underlying ISO-induced myocardial injury, we conducted a bioinformatics analysis using the GSE207581 dataset. GO and KEGG pathway enrichment analyses revealed significant enrichment of genes associated with DNA damage response, DNA repair, protein ubiquitination, chromatin organization, autophagy, cell cycle, mTOR signaling, FoxO signaling, ubiquitin-mediated proteolysis, and nucleocytoplasmic transport. These findings underscore the significance of Mst1 in ISO-induced myocardial injury and highlight its potential as a therapeutic target for mitigating adverse cardiac remodeling. Further investigation into the intricate mechanisms of Mst1 signaling may pave the way for novel therapeutic interventions for myocardial infarction and heart failure.

SNX3 Promotes Doxorubicin-Induced Cardiomyopathy by Regulating GPX4-Mediated Ferroptosis.

The complete molecular mechanism underlying doxorubicin-induced cardiomyopathy remains incompletely elucidated. In this investigation, we engineered mice with cardiomyocyte-specific sorting nexin 3 knockout (SNX3Cko ) to probe the potential protective effects of SNX3 ablation on doxorubicin-triggered myocardial injury, focusing on GPX4-dependent ferroptosis. Our findings indicate that SNX3 deletion normalized heart contractile/relaxation function and thwarted the escalation of cardiac injury biomarkers following doxorubicin exposure. Additionally, SNX3 deletion in the heart mitigated the inflammatory response and oxidative stress in the presence of doxorubicin. At the molecular level, the detrimental effects of doxorubicin-induced cell death, endoplasmic reticulum (ER) stress, and mitochondrial dysfunction were alleviated by SNX3 deficiency. Molecular analysis revealed the activation of GPX4-mediated ferroptosis by doxorubicin, whereas loss of SNX3 prevented the initiation of GPX4-dependent ferroptosis. Furthermore, treatment with erastin, a ferroptosis inducer, markedly reduced cell viability, exacerbated ER stress, and induced mitochondrial dysfunction in SNX3-depleted cardiomyocytes upon doxorubicin exposure. In summary, our results demonstrate that SNX3 deficiency shielded the heart from doxorubicin-induced myocardial dysfunction by modulating GPX4-associated ferroptosis.

CCDC59 alleviates bleomycin-induced inflammation and pulmonary fibrosis by increasing SP-B and SP-C expression in mice.

BACKGROUND: Pulmonary fibrosis is a progressive disease with high incidence and poor prognosis. It is urgent to explore new therapeutic methods for pulmonary fibrosis. As a new treatment method, gene therapy has attracted more and more attention. CCDC59 is a transcriptional coactivator of SP-B and SP-C. Our study mainly aims to explore the effect of overexpression of CCDC59 gene in pulmonary fibrosis of mice. METHODS: CCDC59 overexpressing lentivirus was constructed and then concentrated. RT-qPCR, Western blotting, and immunofluorescence assays were used to detect the expression of CCDC59, SP-B and SP-C protein in cell line and lung tissues after infected with lentivirus. Immunohistochemical staining and hematoxylin-eosin staining assays were used to assess the degree of fibrosis and ELISA assay was used to detect the concentrations of inflammatory factors, SP-B, and SP-C in bronchoalveolar lavage fluid of mice. Dynamic changes of mice lung function at various time points were assessed by lung function test assay. HIPPO pathway and proliferation capacity of alveolar type II epithelial cells were evaluated by immunofluorescence staining and Western blotting. RESULTS: Results showed that endotracheal instillation of CCDC59 overexpressed lentivirus significantly alleviated bleomycin-induced inflammation and pulmonary fibrosis in mice. Overexpression of CCDC59 protein in type II alveolar epithelial cells can enhance the expression of SP-B and SP-C. Overexpression of CCDC59 protein significantly protected against pulmonary inflammatory response and improved lung function of mice. Overexpression of CCDC59 protein significantly alleviated the hyperactivation of HIPPO pathway and increased the proliferative capacity of type II alveolar epithelial cells in lung. CONCLUSION: CCDC59 can alleviate inflammation and pulmonary fibrosis in mice by upregulating the expression of SP-B and SP-C in type II alveolar epithelial cells and alleviating the hyperactivation of HIPPO pathway. Our study offers a new potential treatment for pulmonary fibrosis.

Diterpenoid alkaloids from Delphinium sherriffii.

Three new diterpenoid alkaloids (1, 2, 3) and seventeen known (4-20) compounds were isolated from the whole plant of Delphinium sherriffii Munz (Ranunculaceae). Their structures were elucidated by various spectroscopic analyses, including IR, HR-ESI-MS, 1D and 2D NMR spectra. All compounds were evaluated for the inhibitory activity of Sf9 cells and compound 5 exhibited the strongest cytotoxicity (IC50 = 8.97 µM) against Sf9 cell line.

A multimodal physiological and psychological dataset for human with mental stress induced myocardial ischemia.

Accurate differentiation between angina with no obstructive coronary arteries (ANOCA) and mental stress-induced myocardial ischemia (MSIMI) is crucial for tailored treatment strategies, yet public data scarcity hampers understanding. Given the higher incidence of both conditions in women, this study prospectively enrolled 80 female ANOCA and 39 age-matched female controls, subjecting them to three types of mental stress tasks. ECGs were continuously monitored across Rest, Stress, and Recover stages of the mental stress tasks, with PET/CT imaging during the Stress stage to evaluate myocardial perfusion. With PET/CT serving as the gold standard for MSIMI diagnosis, 35 of the 80 ANOCA patients were diagnosed as MSIMI. Using ECG variables from different stages of mental stress tasks, we developed five machine learning models to diagnose MSIMI. The results showed that ECG data from different stages provide valuable information for MSIMI classification. Additionally, the dataset encompassed demographic details, physiological, and blood sample test results of the patients. We anticipate this new dataset will significantly push further progress in ANOCA and MSIMI research.

miR-540-3p partially recovers the locomotor function of spinal cord injury mice by targeting SIX4/Yap1 and inactivation of astrocytes.

BACKGROUND: Spinal cord injury (SCI) lacks therapeutic reagents. miRNAs are responsible for mesenchymal stem cells (MSCs) therapy in spinal cord injury. PURPOSE: To discover the underlying therapeutic miRNA target and its mechanism for the treatment of SCI. METHOD: Two RNA sequence datasets were retrieved from the GEO Datasets database which was accessed on 30 December 2023. The targets of the top 2 ranked miRNAs (miR-540-3p and miR-433-5p) were analyzed using online databases (miRDB, miRMap, TargetScan and STRING database) and both miRNAs were screened by cell counting kit-8 (CCK-8) assay. Then, transfection and local injection of miR-540-3p were performed to examine the capacity of secretion of astrocytes and the locomotor function of SCI mice. RESULTS: The significantly high levels of miR-540-3p/433-5p were revealed. Transfection of miR-540-3p conferred inactivation of reactive astrocytes and weakened the capacity of secreting inflammatory cytokines of astrocytes. miR-433-5p was proven to not impact the proliferation of astrocytes. Co-culture of culture supernate from astrocytes transfected with miR-540-3p and neurons demonstrated the significantly preserved neurite length and decreased apoptotic level of neurons. Meanwhile, sine oculis homeobox (SIX4)/Yap1, as the target of miR-540-3p, is critical for abrogating inflammatory damage of neurons in vivo and in vitro, decreasing glial scar, and recovering locomotor function of spinal cord injury mice. Furthermore, SCI mice receiving a local injection of miR-540-3p showed smaller and lighter bladder volume and higher limb strength, but the period from urinary retention to autonomous urination of SCI mice showed no significance. CONCLUSIONS: Conclusively, miR-540 discovered from hypoxia-treated exosomes suppresses the inflammatory cytokines secreted by reactive astrocytes, partially preserves the neuronal function of spinal cord injury mice, through the SIX4/Yap1 signalling pathway.

Comparative study of photodynamic therapy (PDT) of cervical low-grade squamous intraepithelial lesion (LSIL).

BACKGROUND: Prevention of high-risk HPV (HR-HPV) infection and effective medical intervention of persistent HPV infection and precancerous lesions are critical for the prevention of cervical cancer. AIMS: The aim of this retrospective comparative study was to evaluate the outcomes of ALA PDT and observation only in the management of low-grade squamous intraepithelial lesions (LSIL). METHODS: In PDT Group (n = 138), ALA PDT was applied to patients with colposcopic biopsy confirmed cervical LSIL accompanied with HR-HPV infection longer than 1 year or HPV 16/18 subtype infection. Cervical LSIL only patients received 3 times of ALA PDT and those with concurrent cervical canal or vaginal lesions received 6 times ALA PDT. Control Group (n = 69) received observation only. Colposcopy, TCT and HPV typing were performed before and after treatment. Patients were followed up for up to two years. RESULT: The observation group showed 26.1%, 34.8% and 53.6% HR-HPV negative conversion at 3-6, 12 and 24 months, respectively. LSIL regression rate of the observation group was 33.33%, 36.23% and 65.22% at 3-6, 12 and 24 months, respectively. There was 62.32%, 80.56% and 89.22% patients achieved HPV clearance at 3-6, 12 and 24 months after PDT treatment, respectively. The LSIL remission rate was 89.86%, 94.40% and 96.08% at 3-6, 12 and 24 months after ALA PDT, respectively. The abnormal TCT (≧ ASCUS) was reduced from 92% to 10.1%, 4.6% and 3.9% at 3-6, 12 and 24 months after ALA PDT, respectively. The patient age was not a factor affecting the clearance of HPV infection and the LSIL regression rate of PDT treatment. CONCLUSIONS: This study demonstrates that the application of multiple ALA PDT treatments has added value in achieving both short-term and long-term HPV and lesion clearance.

The Influence of Homologous Arm Length on Homologous Recombination Gene Editing Efficiency Mediated by SSB/CRISPR-Cas9 in Escherichia coli.

The precise editing of genes mediated by CRISPR-Cas9 necessitates the application of donor DNA with appropriate lengths of homologous arms and fragment sizes. Our previous development, SSB/CRISPR-Cas9, has demonstrated high efficiency in homologous recombination and non-homologous end joining gene editing within bacteria. In this study, we optimized the lengths and sizes of homologous arms of the donor DNA within this system. Two sets of donor DNA constructs were generated: one set comprised donors with only 10-100 bp homologous arms, while the other set included donors with homologous arms ranging from 10-100 bp, between which was a tetracycline resistance expression cassette (1439 bp). These donor constructs were transformed into Escherichia coli MG1655 cells alongside pCas-SSB/pTargetF-lacZ. Notably, when the homologous arms ranged from 10 to 70 bp, the transformation efficiency of non-selectable donors was significantly higher than that of selectable donors. However, within the range of 10-100 bp homologous arm lengths, the homologous recombination rate of selectable donors was significantly higher than that of non-selectable donors, with the gap narrowing as the homologous arm length increased. For selectable donor DNA with homologous arm lengths of 10-60 bp, the homologous recombination rate increased linearly, reaching a plateau when the homologous arm length was between 60-100 bp. Conversely, for non-selectable donor DNA, the homologous recombination rate increased linearly with homologous arm lengths of 10-90 bp, plateauing at 90-100 bp. Editing two loci simultaneously with 100 bp homologous arms, whether selectable or non-selectable, showed no difference in transformation or homologous recombination rates. Editing three loci simultaneously with 100 bp non-selectable homologous arms resulted in a 45% homologous recombination rate. These results suggest that efficient homologous recombination gene editing mediated by SSB/CRISPR-Cas9 can be achieved using donor DNA with 90-100 bp non-selectable homologous arms or 60-100 bp selectable homologous arms.

Design and synthesis of matrine derivatives for anti myocardial ischemia-reperfusion injury by promoting angiogenesis.

Myocardial ischemia/reperfusion (MI/R) is a common cardiovascular disease that seriously affects the quality of life and prognosis of patients. In recent years, matrine has attracted widespread attention in the treatment of cardiovascular diseases. This study designed, synthesized, and characterized 20 new matrine derivatives and studied their protective effects on ischemia-reperfusion injury through in vivo and in vitro experiments. Based on cellular assays, most newly synthesized derivatives have a certain protective effect on Hypoxia/Reoxygenation (H/R) induced H9C2 cell damage, with compound 22 having the best activity and effectively reducing cell apoptosis and necrosis. In vitro experimental data shows that compound 22 can significantly reduce the infarct size of rat myocardium and improve cardiac function after MI/R injury. In summary, compound 22 is a new potential cardioprotective agent that can promote angiogenesis and enhance antioxidant activity by activating ADCY5, CREB3l4, and VEGFA, thereby protecting myocardial cell apoptosis and necrosis induced by MI/R.

Diterpenoid alkaloids from Delphinium trichophorum.

The ethanol extract of the whole plant of Delphinium trichophorum Franch was subjected to a phytochemical study, leading to the isolation of ten unprecedented diterpenoid alkaloids, including nine delnudine-type C20-diterpenoid alkaloids named trichophodines A-I and one kusnezoline-type C20-diterpenoid alkaloid named trichophozine A. Additionally, seven known compounds were also identified. Their structures were elucidated on the basis of extensive spectroscopic analysis, including HSQC, HMBC, 1H-1H COSY, NOESY and X-ray crystallographic analysis. Most isolated compounds were screened for inhibitory activities against LPS-induced NO production in RAW 264.7 macrophage cells and acetylcholinesterase inhibitory effects. Guan-fu base V exhibited potent inhibitory activity against acetylcholinesterase, demonstrating an inhibitory rate of 53.81% at a concentration of 40 µM.

Norditerpenoid alkaloids from Aconitum refractum var. circinatum as autophagy inducers.

A total of twenty-two diterpenoid alkaloids, including ten unprecedented ones, namely refractines C-L, were isolated from the roots of Aconitum refractum (Finet et Gagnep.) Hand.-Mazz. Refractine C was the first example of a natural diterpenoid alkaloid wherein C-19 is linked to N position by an oxaziridine ring. Refractine L was a rare glycosidic diterpenoid alkaloid with fructofuranoside. Most of the isolated compounds obtained from a previous study were screened for their anti-inflammatory and myocardial protective activities. The autophagy-inducing effects of some of these compounds on RAW 264.7 cells were evaluated by assessing the expression of microtubule-associated protein 1 light chain 3 (LC3-II/LC3-I). Results revealed that some compounds exerted varying levels of inhibitory effects on the proliferative activity of RAW 264.7 cells.

Asymmetric Wettability Janus Mesh via Electrostatic Printing for Selective Oil-Water and Emulsion Separation.

Janus mesh with two-sided asymmetric wettability shows high potential for selective oil-water and emulsion separation. However, it remains a challenge to construct Janus mesh structures with good stability and extremely asymmetric wettability. Herein, a novel Janus mesh with asymmetric wettability was structured by two different precursors, polydimethylsiloxane/zinc oxide (PDMS/ZnO) and zinc oxide-polyacrylonitrile/N,N-dimethylformamide (ZnO-PAN/DMF), by electrostatic printing, including electrostatic air spraying and electrostatic spinning. The prepared Janus mesh has special micro-nanostructures on two sides, including PDMS@ZnO and ZnO@PAN. On the basis of gravity, when the placement direction is changed, Janus mesh can effectively separate oil-water mixtures of different densities and surfactant-stabilized oil-water emulsions. Meanwhile, the obtained Janus mesh exhibited good separation efficiency (>96.3%) for various oil-water mixtures, and the flux was up to 2621 ± 30 L m-2 h-1. The Janus mesh was cycled 20 times with no weakening in separation efficiency, indicating satisfactory cycling stability. The Janus mesh displayed good stability under harsh conditions (acidic, alkaline, and high temperature). The Janus mesh can realize low energy input and long-lasting oil-water separation, which has widespread application prospects in intelligent oil-water separation. This top-down electrostatic printing strategy provides a way to construct Janus interface materials with practical applications.

Patterned Photonic Actuators with Dynamic Shape-Morphing and Color-Changing Capabilities Fabricated by Athermal Embossing Technology.

Stimuli-responsive patterned photonic actuators, characterized by their patterned nano/microscale structures and capacity to demonstrate synergistic color changes and shape morphing in response to external stimuli, have attracted intense scientific attention. However, traditional patterned photonic actuator systems still face limitations such as cumbersome and time-consuming preparation processes and small-scale deformations. Herein, we introduce a facile approach involving an athermal embossing technique to rapidly fabricate patterned photonic actuators based on near-infrared (NIR) light-responsive liquid crystal elastomers. The resulting patterned photonic actuators demonstrate remarkable features, including brilliant angle-dependent structural color, complex three-dimensional actuation, and good color durability under NIR light stimulation. As illustrative demonstrations of the proof-of-concept, we fabricate two light-fuelled patterned photonic soft actuators: a butterfly-inspired actuator that can produce wing-flapping dynamic changes in structural color, and an origami crane-shaped actuator with shape memory, structural color information storage, and dynamic display properties. This strategy provides distinct insights into the design and fabrication of various patterned photonic soft robotic devices and intelligent actuators.

Tensile and High Cycle Fatigue Performance at Room and Elevated Temperatures of Laser Powder Bed Fusion Manufactured Hastelloy X.

The application potential of additive manufacturing nickel-based superalloys in aeroengines and gas turbines is extensive, and evaluating their mechanical properties is crucial for promoting the engineering application in load-bearing components. In this study, Hastelloy X alloy was prepared using the laser powder bed fusion process combined with solution heat treatment. The tensile and high cycle fatigue properties were experimentally investigated at room temperature as well as two typical elevated temperatures, 650 °C and 815 °C. It was found that, during elevated-temperature tensile deformation, the alloy exhibits significant serrated flow behavior, primarily observed during the initial stage of plastic deformation at 650 °C but occurring throughout the entire plastic deformation process at 815 °C. Notably, when deformation is small, sawtooth fluctuations are significantly higher at 815 °C compared to 650 °C. Irregular subsurface lack of fusion defects serve as primary sources for fatigue crack initiation in this alloy including both single-source and multi-source initiation mechanisms; moreover, oxidation on fracture surfaces is more prone to occur at elevated temperatures, particularly at 815 °C.

A unidirectional water-transport antibacterial bilayer nanofibrous dressing based on chitosan for accelerating wound healing.

Excessive accumulation of exudate from wounds often causes infection and hinders skin regeneration. To handle wound exudate quickly and prevent infection, we developed an antibacterial Janus nanofibrous dressing with a unidirectional water-transport function. The dressing consists of a hydrophilic chitosan aerogel (CS-A) as the outer layer and a hydrophobic laurylated chitosan (La-CS) nanofibrous membrane as the inner layer. These dressings achieved excellent liquid absorption performance (2987.8 ±â€¯123.5 %), air and moisture permeability (997.8 ±â€¯23.1 g/m2/day) and mechanical strength (5.1 ±â€¯2.6 MPa). This performance was obtained by adjusting the density of CS-A and the thickness of the La-CS membrane. Moreover, the dressing did not induce significant toxicity to cells and can prevent bacterial aggregation and infection at the wound site. Animal experiments showed that the dressing can shorten the inflammatory phase, enhance blood vessel generation, and accelerate collagen deposition, thus promoting wound healing. Overall, these results suggest that this Janus dressing is a promising material for clinical wound care.