Jmjd1c demethylates STAT3 to restrain plasma cell differentiation and rheumatoid arthritis.

Appropriate regulation of B cell differentiation into plasma cells is essential for humoral immunity while preventing antibody-mediated autoimmunity; however, the underlying mechanisms, especially those with pathological consequences, remain unclear. Here, we found that the expression of Jmjd1c, a member of JmjC domain histone demethylase, in B cells but not in other immune cells, protected mice from rheumatoid arthritis (RA). In humans with RA, JMJD1C expression levels in B cells were negatively associated with plasma cell frequency and disease severity. Mechanistically, Jmjd1c demethylated STAT3, rather than histone substrate, to restrain plasma cell differentiation. STAT3 Lys140 hypermethylation caused by Jmjd1c deletion inhibited the interaction with phosphatase Ptpn6 and resulted in abnormally sustained STAT3 phosphorylation and activity, which in turn promoted plasma cell generation. Germinal center B cells devoid of Jmjd1c also acquired strikingly increased propensity to differentiate into plasma cells. STAT3 Lys140Arg point mutation completely abrogated the effect caused by Jmjd1c loss. Mice with Jmjd1c overexpression in B cells exhibited opposite phenotypes to Jmjd1c-deficient mice. Overall, our study revealed Jmjd1c as a critical regulator of plasma cell differentiation and RA and also highlighted the importance of demethylation modification for STAT3 in B cells.

25-Hydroxycholesterol regulates lysosome AMP kinase activation and metabolic reprogramming to educate immunosuppressive macrophages.

Macrophages are critical to turn noninflamed "cold tumors" into inflamed "hot tumors". Emerging evidence indicates abnormal cholesterol metabolites in the tumor microenvironment (TME) with unclear function. Here, we uncovered the inducible expression of cholesterol-25-hydroxylase (Ch25h) by interleukin-4 (IL-4) and interleukin-13 (IL-13) via the transcription factor STAT6, causing 25-hydroxycholesterol (25HC) accumulation. scRNA-seq analysis confirmed that CH25Hhi subsets were enriched in immunosuppressive macrophage subsets and correlated to lower survival rates in pan-cancers. Targeting CH25H abrogated macrophage immunosuppressive function to enhance infiltrating T cell numbers and activation, which synergized with anti-PD-1 to improve anti-tumor efficacy. Mechanically, lysosome-accumulated 25HC competed with cholesterol for GPR155 binding to inhibit the kinase mTORC1, leading to AMPKα activation and metabolic reprogramming. AMPKα also phosphorylated STAT6 Ser564 to enhance STAT6 activation and ARG1 production. Together, we propose CH25H as an immunometabolic checkpoint, which manipulates macrophage fate to reshape CD8+ T cell surveillance and anti-tumor response.

Aerobic training attenuates cardiac remodeling in mice post-myocardial infarction by inhibiting the p300/CBP-associated factor.

Aerobic training (AT), an effective form of cardiac rehabilitation, has been shown to be beneficial for cardiac repair and remodeling after myocardial infarction (MI). The p300/CBP-associated factor (PCAF) is one of the most important lysine acetyltransferases and is involved in various biological processes. However, the role of PCAF in AT and AT-mediated cardiac remodeling post-MI has not been determined. Here, we found that the PCAF protein level was significantly increased after MI, while AT blocked the increase in PCAF. AT markedly improved cardiac remodeling in mice after MI by reducing endoplasmic reticulum stress (ERS). In vivo, similar to AT, pharmacological inhibition of PCAF by Embelin improved cardiac recovery and attenuated ERS in MI mice. Furthermore, we observed that both IGF-1, a simulated exercise environment, and Embelin protected from H2O2-induced cardiomyocyte injury, while PCAF overexpression by viruses or the sirtuin inhibitor nicotinamide eliminated the protective effect of IGF-1 in H9C2 cells. Thus, our data indicate that maintaining low PCAF levels plays an essential role in AT-mediated cardiac protection, and PCAF inhibition represents a promising therapeutic target for attenuating cardiac remodeling after MI.

The dysfunction of CD8+ T cells triggered by endometriotic stromal cells promotes the immune survival of endometriosis.

Endometriosis is defined as an oestrogen-dependent and inflammatory gynaecological disease of which the pathogenesis remains unclear. This study aimed to investigate the cellular heterogeneity and reveal the effect of CD8+ T cells on the progress of endometriosis. Three ovarian endometriosis patients were collected, and single-cell RNA sequencing (scRNA-seq) progressed and delineated the cellular landscape of endometriosis containing five cell clusters. The endometrial cells (EMCs) were the major component, of which the mesenchymal cells were preponderant and characterized with increased inflammation and oestrogen synthesis in endometriosis. The proportion of T cells, mainly CD8+ T cells rather than CD4+, was reduced in endometriotic lesions, and the cytokines and cytotoxicity of ectopic T cells were depressed. CD8+ T cells depressed the proliferation of ESCs through inhibiting CDK1/CCNB1 pathway to arrest the cell cycle and triggered inflammation through activating STAT1 pathway. Correspondingly, the coculture with ESCs resulted in the dysfunction of CD8+ T cells through upregulating STAT1/PDCD1 pathway and glycolysis-promoted metabolism reprogramming. The endometriotic lesions were larger in nude mouse models with T-cell deficiency than the normal mouse models. The inhibition of T cells via CD90.2 or CD8A antibody increased the endometriotic lesions in mouse models, and the supplement of T cells to nude mouse models diminished the lesion sizes. In conclusion, this study revealed the global cellular variation of endometriosis among which the cellular count and physiology of EMCs and T cells were significantly changed. The depressed cytotoxicity and aberrant metabolism of CD8+ T cells were induced by ESCs with the activation of STAT1/PDCD1 pathway resulting in immune survival to promote endometriosis.

Multi-omics integration highlights the role of ubiquitination in endometriosis fibrosis.

BACKGROUND: Endometriosis, characterized by the presence of active endometrial-like tissues outside the uterus, causes symptoms like dysmenorrhea and infertility due to the fibrosis of endometrial cells, which involves excessive deposition of extracellular matrix (ECM) proteins. Ubiquitination, an important post-transcriptional modification, regulates various biological processes in human diseases. However, its role in the fibrosis process in endometriosis remains unclear. METHODS: We employed multi-omics approaches on two cohorts of endometriosis patients with 39 samples. GO terms and KEGG pathways enrichment analyses were used to investigate the functional changes involved in endometriosis. Pearson's correlation coefficient analysis was conducted to explore the relationship between global proteome and ubiquitylome in endometriosis. The protein expression levels of ubiquitin-, fibrosis-related proteins, and E3 ubiquitin-protein ligase TRIM33 were validated via Western blot. Transfecting human endometrial stroma cells (hESCs) with TRIM33 small interfering RNA (siRNA) in vitro to explore how TRIM33 affects fibrosis-related proteins. RESULTS: Integration of proteomics and transcriptomics showed genes with concurrent change of both mRNA and protein level which involved in ECM production in ectopic endometria. Ubiquitylomics distinguished 1647 and 1698 ubiquitinated lysine sites in the ectopic (EC) group compared to the normal (NC) and eutopic (EU) groups, respectively. Further multi-omics integration highlighted the essential role of ubiquitination in key fibrosis regulators in endometriosis. Correlation analysis between proteome and ubiquitylome showed correlation coefficients of 0.32 and 0.36 for ubiquitinated fibrosis proteins in EC/NC and EC/EU groups, respectively, indicating positive regulation of fibrosis-related protein expression by ubiquitination in ectopic lesions. We identified ubiquitination in 41 pivotal proteins within the fibrosis-related pathway of endometriosis. Finally, the elevated expression of TGFBR1/α-SMA/FAP/FN1/Collagen1 proteins in EC tissues were validated across independent samples. More importantly, we demonstrated that both the mRNA and protein levels of TRIM33 were reduced in endometriotic tissues. Knockdown of TRIM33 promoted TGFBR1/p-SMAD2/α-SMA/FN1 protein expressions in hESCs but did not significantly affect Collagen1/FAP levels, suggesting its inhibitory effect on fibrosis in vitro. CONCLUSIONS: This study, employing multi-omics approaches, provides novel insights into endometriosis ubiquitination profiles and reveals aberrant expression of the E3 ubiquitin ligase TRIM33 in endometriotic tissues, emphasizing their critical involvement in fibrosis pathogenesis and potential therapeutic targets.

The Feasibility and Accuracy of Holographic Navigation with Laser Crosshair Simulator Registration on a Mixed-Reality Display.

Addressing conventional neurosurgical navigation systems' high costs and complexity, this study explores the feasibility and accuracy of a simplified, cost-effective mixed reality navigation (MRN) system based on a laser crosshair simulator (LCS). A new automatic registration method was developed, featuring coplanar laser emitters and a recognizable target pattern. The workflow was integrated into Microsoft's HoloLens-2 for practical application. The study assessed the system's precision by utilizing life-sized 3D-printed head phantoms based on computed tomography (CT) or magnetic resonance imaging (MRI) data from 19 patients (female/male: 7/12, average age: 54.4 ± 18.5 years) with intracranial lesions. Six to seven CT/MRI-visible scalp markers were used as reference points per case. The LCS-MRN's accuracy was evaluated through landmark-based and lesion-based analyses, using metrics such as target registration error (TRE) and Dice similarity coefficient (DSC). The system demonstrated immersive capabilities for observing intracranial structures across all cases. Analysis of 124 landmarks showed a TRE of 3.0 ± 0.5 mm, consistent across various surgical positions. The DSC of 0.83 ± 0.12 correlated significantly with lesion volume (Spearman rho = 0.813, p < 0.001). Therefore, the LCS-MRN system is a viable tool for neurosurgical planning, highlighting its low user dependency, cost-efficiency, and accuracy, with prospects for future clinical application enhancements.

Mechanism of an RBM-targeted rabbit monoclonal antibody 9H1 neutralizing SARS-CoV-2.

The COVID-19 pandemic, caused by SARS-CoV-2, has led to over 750 million infections and 6.8 million deaths worldwide since late 2019. Due to the continuous evolution of SARS-CoV-2, many significant variants have emerged, creating ongoing challenges to the prevention and treatment of the pandemic. Therefore, the study of antibody responses against SARS-CoV-2 is essential for the development of vaccines and therapeutics. Here we perform single particle cryo-electron microscopy (cryo-EM) structure determination of a rabbit monoclonal antibody (RmAb) 9H1 in complex with the SARS-CoV-2 wild-type (WT) spike trimer. Our structural analysis shows that 9H1 interacts with the receptor-binding motif (RBM) region of the receptor-binding domain (RBD) on the spike protein and by directly competing with angiotensin-converting enzyme 2 (ACE2), it blocks the binding of the virus to the receptor and achieves neutralization. Our findings suggest that utilizing rabbit-derived mAbs provides valuable insights into the molecular interactions between neutralizing antibodies and spike proteins and may also facilitate the development of therapeutic antibodies and expand the antibody library.

Crystal Face Dominated Fabrication of Prussian Blue Analogue with Oriented Growth and Naturally Nonpreferred Unsaturated Coordination Center.

Defects, such as unsaturated coordination centers and vacancies, can fundamentally change materials' inherent properties and growth habits. The development of defect engineering has promoted the application of many technologies, but it is still a great challenge to selectively manufacture defect sites in existing material systems. It is shown here that in situ site-directed tailoring of metal sites in Prussian blue analogs (PBA) can be achieved according to the reducibility differences of different metal atoms, forming naturally nonpreferred unsaturated coordination centers. Meanwhile, the in situ capture of small reducing molecule can realize site-directed tailoring of crystal facets during crystal growth and results in oriented 1D growth. As an oxygen evolution reaction catalyst, the resulted PBA with the nonpreferred unsaturated coordination centers shows a low overpotential of 239 mV at 10 mA cm-2 in alkali, superior to the original PBAs and the previously reported defective PBA derivatives, which can be ascribed to the unsaturated coordination active center and the unique 1D structure. This work opens up opportunities for producing naturally nonpreferred unsaturated coordination center in nanomaterials for broad applications.

Has breeding altered the light environment, photosynthetic apparatus, and photosynthetic capacity of wheat leaves?

Whether photosynthesis has improved with increasing yield in major crops remains controversial. Research in this area has often neglected to account for differences in light intensity experienced by cultivars released in different years. Light intensity is expected to be positively associated with photosynthetic capacity and the resistance of the photosynthetic apparatus to high light but negatively associated with light-utilization efficiency under low light. Here, we analyzed the light environment, photosynthetic activity, and protein components of leaves of 26 winter wheat cultivars released during the past 60 years in China. Over time, light levels on flag leaves significantly decreased due to architectural changes, but photosynthetic rates under high or low light and the resistance of the photosynthetic apparatus to high light remained steady, contrary to expectations. We propose that the difference between the actual and expected trends is due to breeding. Specifically, breeding has optimized photosynthetic performance under high light rather than low light. Moreover, breeding selectivity altered the stoichiometry of several proteins related to dynamic photosynthesis, canopy light distribution, and photoprotection. These results indicate that breeding has significantly altered the photosynthetic mechanism in wheat and its response to the light environment. These changes likely have helped increase wheat yields.

Transcervical inflatable mediastinoscopic esophagectomy versus thoracoscopic esophagectomy for local early- and intermediate-stage esophageal squamous cell carcinoma: A propensity score-matched analysis.

BACKGROUND AND OBJECTIVE: Transcervical inflatable mediastinoscopic esophagectomy (TIME) is a novel method of minimally invasive esophagectomy (MIE) for esophageal cancer. However, whether TIME is effective and feasible as conventional MIE remains unclear. This study aimed to evaluate the efficacy of TIME by comparing it with thoracoscopic esophagectomy (TE). METHODS: Surgical outcomes and relapse-free survival (RFS) rates of patients with local early- or intermediate-stage thoracic esophageal squamous cell carcinoma that underwent TIME or TE from January 2017 to December 2019 were analyzed in this retrospective study. Propensity score matching was used to control the confounding factors. RESULTS: The mean operation time in TIME was shorter than that in TE (p < 0.05). Patients in the TIME group achieved postoperative ambulation earlier than those in the TE group (p < 0.05). The rate of pulmonary complications was lower in TIME than in TE (p < 0.05). The number of lymph nodes harvested during surgery and the RFS rates of two groups did not have significant differences. CONCLUSION: TIME may be a feasible and safe method to treat local early- and intermediate-stage thoracic esophageal squamous cell carcinoma effectively and it could be a supplementary surgical method of TE for patients with poor pulmonary function or cannot undergo TE.

Comparison of mortality and complications between urgent-start peritoneal dialysis and urgent-start hemodialysis: A systematic review and meta-analysis.

The advantages of urgent-start peritoneal dialysis (PD) vis-à-vis urgent-start hemodialysis (HD) are not clear. We performed a systematic review and meta-analysis of studies comparing the two modalities. Databases of PubMed, Embase, Ovoid, and Google Scholar were searched up to November 1, 2020. The primary outcome was mortality, and secondary outcomes were dialysis-related infectious complications and mechanical complications. Risk ratios (RRs) were calculated for all outcomes. Seven studies were included. The pooled analysis revealed a statistically significant reduced risk of all-cause mortality in patients undergoing urgent-start PD as compared to urgent-start HD (RR: 0.61, 95% confidence interval [CI] [0.40, 0.94], I2  = 56.34%). A meta-analysis of dialysis-related infectious complications indicated no statistically significant difference between the two modalities (RR: 0.66, 95% CI [0.29, 1.50], I2  = 69.62%). Our analysis revealed a statistically significant reduced risk of mechanical complications in patients undergoing urgent-start PD (RR: 0.54, 95% CI [0.40, 0.73], I2  = 0%). To conclude, unadjusted data from observational studies are indicative of lower mortality and lower risk of mechanical complications with urgent-start PD versus urgent-start HD. The risk of infectious complications was not different between the two groups. Further studies with a larger sample size using propensity-matched cohorts are needed to strengthen current evidence.

Inhibition of mitochondrial complex III induces differentiation in acute myeloid leukemia.

Although acute myeloid leukemia (AML) is a highly heterogeneous disease with diverse genetic subsets, one hallmark of AML blasts is myeloid differentiation blockade. Extensive evidence has indicated that differentiation induction therapy represents a promising treatment strategy. Here, we identified that the pharmacological inhibition of the mitochondrial electron transport chain (ETC) complex III by antimycin A inhibits proliferation and promotes cellular differentiation of AML cells. Mechanistically, we showed that the inhibition of dihydroorotate dehydrogenase (DHODH), a rate-limiting enzyme in de novo pyrimidine biosynthesis, is involved in antimycin A-induced differentiation. The activity of antimycin A could be reversed by supplement of excessive amounts of exogenous uridine as well as orotic acid, the product of DHODH. Furthermore, we also found that complex III inhibition exerts a synergistic effect in differentiation induction combined with DHODH inhibitor brequinar as well as with the pyrimidine salvage pathway inhibitor dipyridamole. Collectively, our study uncovered the link between mitochondrial complex III and AML differentiation and may provide further insight into the potential application of mitochondrial complex III inhibitor as a mono or combination treatment in differentiation therapy of AML.

Long non-coding RNA HEIH suppresses the expression of TP53 through enhancer of zeste homolog 2 in oesophageal squamous cell carcinoma.

It is increasingly evident that the molecular and biological functions of long non-coding RNAs (lncRNA) are vital for understanding the molecular biology and progression of cancer. The lncRNA-HEIH, a newly identified lncRNA, has been demonstrated to be up-regulated in hepatocellular cancer. However, little is known about its role in oesophageal squamous cell carcinoma (ESCC). In the present study, an obvious up-regulation of lncRNA-HEIH was observed in ESCC compared to the adjacent normal tissues. Meanwhile, patients with high expression of lncRNA-HEIH have significantly poorer prognosis than those with low expression. We further found that lncRNA-HEIH was associated with enhancer of zeste homolog 2 (EZH2) and that this association led to the repression of TP53. These findings indicate that lncRNA-HEIH may serve as a prognostic marker and a potential therapeutic target for ESCC.

RhoA/ROCK pathway mediates the effect of oestrogen on regulating epithelial-mesenchymal transition and proliferation in endometriosis.

Endometriosis is a benign gynaecological disease appearing with pelvic pain, rising dysmenorrhoea and infertility seriously impacting on 10% of reproductive-age females. This research attempts to demonstrate the function and molecular mechanism of RhoA/ROCK pathway on epithelial-mesenchymal transition (EMT) and proliferation in endometriosis. The expression of Rho family was abnormally changed in endometriotic lesions; in particular, RhoA and ROCK1/2 were significantly elevated. Overexpression of RhoA in human eutopic endometrial epithelial cells (eutopic EECs) enhanced the cell mobility, epithelial-mesenchymal transition (EMT) and proliferation, and RhoA knockdown exhibited the opposite function. Oestrogen up-regulated the RhoA activity and expression of RhoA and ROCK1/2. RhoA overexpression reinforced the effect of oestrogen on promoting EMT and proliferation, and RhoA knockdown impaired the effect of oestrogen. oestrogen receptor α (ERα) was involved with the regulation of oestrogen on EMT and proliferation and up-regulated RhoA activity and expression of RhoA and ROCK1/2. The function of ERα was modulated by the change in RhoA expression. Furthermore, phosphorylated ERK that was enhanced by oestrogen and ERα promoted the protein expression of RhoA/ROCK pathway. Endometriosis mouse model revealed that oestrogen enhanced the size and weight of endometriotic lesions. The expression of RhoA and phosphorylated ERK in mouse endometriotic lesions was significantly elevated by oestrogen. We conclude that abnormal activated RhoA/ROCK pathway in endometriosis is responsible for the function of oestrogen/ERα/ERK signalling, which promoted EMT and proliferation and resulted in the development of endometriosis.

Ubiquitination of NOTCH2 by DTX3 suppresses the proliferation and migration of human esophageal carcinoma.

The NOTCH2 gene plays a role in the development of many tumors. Deltex E3 ubiquitin ligase 3 (DTX3) was identified as a novel E3 ligase for NOTCH2 and as a potential therapeutic target for esophageal cancer. However, whether DTX3 could regulate NOTCH2 to suppress the progression of esophageal carcinoma remains unknown. In our study, NOTCH2 had higher expression in human esophageal carcinoma cell lines compared to normal human esophageal epithelial cell line, and ablation of NOTCH2 suppressed the proliferation and migration of esophageal carcinoma cells. A novel E3 ligase for NOTCH2 was identified by yeast two-hybrid (Y2H) screening, and DTX3 promoted the ubiquitination and degradation of NOTCH2. Further study showed that DTX3 overexpression suppressed the proliferation and tumorigenicity of human oesophageal carcinoma cells. The analysis of tissue samples from patients revealed that the expression of NOTCH2 was high while the expression of DTX3 was low in esophageal cancer. Furthermore, the expression of DTX3 and NOTCH2 showed a significant negative correlation in human oesophageal cancer samples. Our study suggested that the DTX3-NOTCH2 axis plays an important role in the progression of esophageal cancer, and DTX3 acts as an anti-oncogene in esophageal carcinoma, potentially offering a therapeutic target for esophageal cancer.

Shp2 Inhibits Proliferation of Esophageal Squamous Cell Cancer via Dephosphorylation of Stat3.

Shp2 (Src-homology 2 domain-containing phosphatase 2) was originally reported as an oncogene in kinds of solid tumors and hematologic malignancies. However, recent studies indicated that Shp2 may act as tumor suppressors in several tumor types. We investigated the function of Shp2 in esophageal squamous cell cancer (ESCC). The expression level of Shp2 was analyzed in tumor tissues in comparison with adjacent normal tissues of ESCC patients by immunohistochemistry and Western blot. Shp2 was knocked down by Short hairpin RNA to evaluate its function in ESCC cell lines. The relationship between Shp2 and p-Stat3 (signal transducer and activator of transcription 3) in human ESCC tissues was statistically examined. A significant low expression of Shp2 was found in ESCC tissues. Low expression of Shp2 was related to poorer overall survival in patients from The Cancer Genome Atlas (TCGA) dataset. Knockdown of Shp2 increased the growth of ESCC cell lines both in vivo and vitro. Activation of Stat3 (p-Stat3) was induced by Shp2 depletion. Expression of p-Stat3 was negatively correlated with Shp2 expression in ESCC tissues. Furthermore, knockdown of Shp2 attenuated cisplatin-sensitivity of ESCC cells. Shp2 might suppress the proliferation of ESCC by dephosphorylation of p-Stat3 and represents a novel research field for targeted therapy.

Stabilization of multiple rib fractures in a canine model.

BACKGROUND: Operative stabilization is frequently used in the clinical treatment of multiple rib fractures (MRF); however, no ideal material exists for use in this fixation. This study investigates a newly developed biodegradable plate system for the stabilization of MRF. METHODS: Silk fiber-reinforced polycaprolactone (SF/PCL) plates were developed for rib fracture stabilization and studied using a canine flail chest model. Adult mongrel dogs were divided into three groups: one group received the SF/PCL plates, one group received standard clinical steel plates, and the final group did not undergo operative fracture stabilization (n = 6 for each group). Radiographic, mechanical, and histologic examination was performed to evaluate the effectiveness of the biodegradable material for the stabilization of the rib fractures. RESULTS: No nonunion and no infections were found when using SF-PCL plates. The fracture sites collapsed in the untreated control group, leading to obvious chest wall deformity not encountered in the two groups that underwent operative stabilization. CONCLUSIONS: Our experimental study shows that the SF/PCL plate has the biocompatibility and mechanical strength suitable for fixation of MRF and is potentially ideal for the treatment of these injuries.

Reconstruction of large-size abdominal wall defect using biodegradable poly-p-dioxanone mesh: an experimental canine study.

BACKGROUND: Reconstruction of large-size abdominal wall defect (AWDs) is a huge challenge faced in current surgical practice. In this study, we aimed to evaluate the effectiveness and safety of biodegradable poly-p-dioxanone (PDO) mesh for reconstructing large-size AWDs in an experimental canine model. METHODS: Eighteen experimental canines were randomly and equally divided into three groups, namely, a PDO group, a Marlex group and a control group (n = 6 each). Following the creation of a 6 cm × 5.5 cm AWD, PDO mesh and Marlex mesh were used to reconstruct the defect in the PDO and Marlex groups, respectively. The defect was closed using relaxation sutures alone in the control group. Animals were killed 24 weeks after surgery, and reconstruction outcomes were evaluated using radiography, histology and biomechanical testing. RESULTS: All animals except those in the control group survived the experiment. The PDO group showed no wound dehiscence, herniation or infection, whereas the animals in the Marlex group exhibited marked foreign body reactions. The PDO group had less intraabdominal adhesion than the Marlex group. As shown by radiography, histology and biomechanical testing, PDO mesh exhibited complete degradation and favorable biochemical strength at 24 weeks postsurgery. CONCLUSIONS: PDO mesh implantation is an effective, safe treatment modality for reconstructing large-size AWDs.

Study on CFRP-Strengthened Welded Steel Plates with Inclined Welds Considering Welding Residual Stress.

Welded steel plates are widely used in various structural applications, and the presence of inclined welds is often encountered in practical scenarios. Carbon fiber reinforced polymer (CFRP) has been proven to be effective for strengthening steel structures. However, the behavior of CFRP-strengthened welded steel plates with inclined welds, particularly considering the influence of welding residual stress, is limited. This paper aims to investigate the tensile behavior of CFRP-strengthened welded Q355 steel plates with inclined welds considering welding residual stress (WRS). First, WRS data were obtained by the X-ray diffraction (XRD) method at different locations. The maximum tensile and compressive residual stresses are 0.39 and 0.14 times the yield strength of the steel, respectively. Then, finite element models were established to investigate the effects of weld angles, weld width, and height on the WRS distribution of welded steel plates. Finally, the tensile performance of CFRP-strengthened welded plates with WRS was studied by numerical simulation. The results showed that the weld angles have little effect on the distribution pattern of residual stress but significantly affect the peak tensile WRS. When the weld angle changes from 0° to 60°, the peak tensile WRS decreases significantly from 0.32 to 0.06 times the yield strength of steel; furthermore, the influence of weld width and height on WRS is relatively limited. Under tension loading, the maximum stress occurs near the weld. The ends of the weld enter the yielding state later than the middle part of the weld due to the distribution of the WRS. As the weld angle increases and the length of the weld increases, the stress in the weld zone decreases, while the stress in the base material zone correspondingly increases. In addition, CFRP strengthening can reduce the magnitude of stress. This study provides preliminary references for understanding the tensile behavior of CFRP-strengthened welded steel plates with inclined welds.

Predicting the Effect of the Loading Rate on the Fracture Toughness of Hydraulic Asphalt Concrete Based on the Weibull Distribution.

The cracking problem of asphalt concrete panels is a crucial consideration in the design of hydraulic asphalt concrete seepage control bodies. Panels experiencing uneven rises or falls of water levels during impoundment may exhibit loading rate effects. Investigating the fracture toughness value of asphalt concrete under varying loading rates is essential. This study employs a statistical method to calculate the fracture index KIC, using the semi-circular bending test (SCB) to examine the effect of loading rates on the Type I fracture mode of hydraulic asphalt concrete. The data are analyzed using the two-parameter Weibull distribution curve, offering insights into the minimum number of KIC test specimens. The results indicate an increase in KIC with loading rate, with greater data dispersion at faster rates. The Weibull distribution curve successfully fits the fracture behavior under different loading rates, providing valuable predictions. This study estimates the minimum number of SCB test specimens to be nine, based on a confidence level of 0.95 and a relative deviation not exceeding 5%.