Transcutaneous auricular vagus nerve stimulation enhanced emotional inhibitory control via increasing intrinsic prefrontal couplings.

Background: Inhibitory control represents a core executive function that critically facilitates adaptive behavior and survival in an ever-changing environment. Non-invasive transcutaneous auricular vagus nerve stimulation (taVNS) has been hypothesized to improve behavioral inhibition performance, however the neurocomputational mechanism of taVNS-induced neuroenhancement remains elusive. Method: In the current study, we investigated the efficacy of taVNS in a sham-controlled between-subject functional near infrared spectroscopy (fNIRS) experiment with an emotional face Go/No-Go paradigm in ninety healthy young adults. Results: After a data quality check, eighty-two subjects were included in the final data analysis. Behaviorally, the taVNS improved No-Go response accuracy, together with computational modeling using Hierarchical Bayesian estimation of the Drift Diffusion Model (HDDM) indicating that it specifically reduced the information accumulation rate for Go responses, and this was negatively associated with increased accuracy of No-Go responses. On the neural level, taVNS enhanced engagement of the bilateral inferior frontal gyrus (IFG) during inhibition of angry expression faces and modulated functional couplings (FCs) within the prefrontal inhibitory control network. Mediation models revealed that taVNS-induced facilitation of inhibitory control was critically mediated by a decreased information accumulation for Go responses and concomitantly enhanced neurofunctional coupling between the inferior and orbital frontal cortex. Discussion: Our findings demonstrate a potential for taVNS to improve emotional inhibitory control via reducing pre-potent responses and enhancing FCs within prefrontal inhibitory control networks, suggesting a promising therapeutic role in treating specific disorders characterized by inhibitory control deficits.

Characteristics and functions of memory regulatory T cells in normal pregnancy cycle and pregnancy complications.

Regulatory T cells (Tregs) are activated and expanded after exposure to fetal-specific (paternal) antigens. A proportion of Tregs differentiate into memory Tregs (mTregs), exhibiting immune memory function and exerting more potent immunosuppression than naive Tregs (nTregs). However, it is unclear how mTregs are regulated during normal and pathological pregnancies (e.g., gestational diabetes mellitus (GDM) and preeclampsia (PE)). In this study, PD-1, HLA-G, and HLA-DR expressions on memory CD4+ T cells, naive CD4+ T cells, Tregs, mTregs, and nTregs in healthy non-pregnant women (n=20), healthy first (n=20), second (n=20), and third-trimester women (n=20), postpartum women (n=20), GDM (n=20), and PE patients (n=20) were analyzed. The proportion of mTregs out of Tregs was increased (P<0.05) in the first trimester compared with that in non-pregnancy and reduced in the second and third trimesters. The proportions of PD-1+ Tregs and mTregs were significantly increased during the first trimester compared to those of non-pregnancy (P<0.01), reached their maximum in the second trimester. Moreover, the proportions of HLA-G+ memory CD4+ T cells, Tregs, and mTregs were increased in the first and second trimesters (P<0.01), reached their maximum in the third trimester. GDM patients were characterized by significantly lower percentages of PD-1+ and HLA-G+ mTregs (P<0.01), while PE patients were characterized by significantly lower percentages of HLA-G+ mTregs (P<0.01), compared with the healthy third-trimester women. In general, as demonstrated by this study, mTregs increase in number and enhance maternal-fetal immunoregulation during pregnancy, and their dysfunction can result in pregnancy complications such as GMD or PE.

Analysis of clinical characteristics of infections caused by shewanella species.

PURPOSE: The Shewanella genus is a rare pathogen of marine origin. In recent years, there has been a continuous increase in infection cases caused by this bacterium, and we have observed the uniqueness of infections caused by this microorganism. MATERIALS AND METHODS: This study conducted a retrospective analysis of the medical history and laboratory examination data of patients infected with the Shewanella genus over the past decade. Additionally, it employed bioinformatics methods to analyze the relevant virulence factors and antibiotic resistance genes associated with the Shewanella genus. RESULTS: Over the past 10 years, we have isolated 51 cases of Shewanella, with 68.82% being Shewanella putrefaciens (35/51 cases) and 31.37% being Shewanella algae (16/51 cases). Infected individuals often had underlying diseases, with 39.22% (20/51) having malignant tumors and 25.49% (13/51) having liver and biliary system diseases primarily characterized by stones. The majority of patients, 62.74% (32/51), exhibited mixed infections, including one case with a combination of infections from three other types of bacteria and five cases with a combination of infections from two other types of bacteria. The identified microorganisms were commonly resistant to ticarcillin-clavulanic acid (23.5%), followed by cefoperazone-sulbactam (19.6%), ciprofloxacin (17.6%), and cefotaxime (17.6%). Bioinformatics analysis indicates that Shewanella can express bile hydrolysis regulators and fatty acid metabolism regulators that aid in adapting to the unique environment of the biliary tract. Additionally, it expresses abundant catalase, superoxide dismutase, and two-component signal transduction system proteins, which may be related to environmental adaptation. Shewanella also expresses various antibiotic resistance genes, including beta-lactamases and aminoglycoside modification enzymes. Iron carriers may be one of its important virulence factors. CONCLUSIONS: We speculate that the Shewanella genus may exist as a specific colonizer in the human body, and under certain conditions, it may act as a pathogen, leading to biliary infections in the host.

Analysis of heavy metal and polycyclic aromatic hydrocarbon pollution characteristics of a typical metal rolling industrial site based on data mining.

With the transformation and upgrading of industries, the environmental problems caused by industrial residual contaminated sites are becoming increasingly prominent. Based on actual investigation cases, this study analyzed the soil pollution status of a remaining sites of the copper and zinc rolling industry, and found that the pollutants exceeding the screening values included Cu, Ni, Zn, Pb, total petroleum hydrocarbons and 6 polycyclic aromatic hydrocarbon monomers. Based on traditional analysis methods such as the correlation coefficient and spatial distribution, combined with machine learning methods such as SOM + K-means, it is inferred that the heavy metal Zn/Pb may be mainly related to the production history of zinc rolling. Cu/Ni may be mainly originated from the production history of copper rolling. PAHs are mainly due to the incomplete combustion of fossil fuels in the melting equipment. TPH pollution is speculated to be related to oil leakage during the industrial use period and later period of vehicle parking. The results showed that traditional analysis methods can quickly identify the correlation between site pollutants, while SOM + K-means machine learning methods can further effectively extract complex hidden relationships in data and achieve in-depth mining of site monitoring data.

Chrysin inhibits ferroptosis of cerebral ischemia/reperfusion injury via regulating HIF-1α/CP loop.

Chrysin is a natural flavonoid with powerful neuroprotective capacity. Cerebral ischemia/reperfusion injury (CIRI) is associated with oxidative stress and ferroptosis. Hypoxia-inducible factor 1α (HIF-1α) and ceruloplasmin (CP) are the critical targets for oxidation reactions and iron transport. But the regulatory mechanism between them is still unclear. Transient middle cerebral artery occlusion (tMCAO) model in rats and oxygen and glucose deprivation/re-oxygenation (OGD/R) model in PC12 cells were applied. Pathological tissue staining and biochemical kit were used to evaluate the effect of chrysin. The relationship between HIF-1α and CP was verified by transcriptomics, qRT-PCR and Western blot. In CIRI, HIF-1α/CP loop was discovered to be the regulatory pathway of ferroptosis. CIRI led to activation and nuclear translocation of HIF-1α, which promoted CP transcription and translation, and downstream ferroptosis. Inhibition of HIF-1α had opposite effect on CP and ferroptosis regulation. Overexpression of CP increased the expression of HIF-1α, nevertheless, inhibited the nuclear translocation of HIF-1α and alleviated CIRI. Silencing CP promoted HIF-1α elevation in nucleus and aggravated CIRI. Mechanistically, chrysin restrained HIF-1α nuclear translocation, thereby inhibiting CP transcription and translation, which in turn reduced downstream HIF-1α expression and mitigated ferroptosis in CIRI. Our results highlight chrysin restrains ferroptosis in CIRI through HIF-1α/CP loop.

Pelvic bone tumor segmentation fusion algorithm based on fully convolutional neural network and conditional random field.

Background and objective: Pelvic bone tumors represent a harmful orthopedic condition, encompassing both benign and malignant forms. Addressing the issue of limited accuracy in current machine learning algorithms for bone tumor image segmentation, we have developed an enhanced bone tumor image segmentation algorithm. This algorithm is built upon an improved full convolutional neural network, incorporating both the fully convolutional neural network (FCNN-4s) and a conditional random field (CRF) to achieve more precise segmentation. Methodology: The enhanced fully convolutional neural network (FCNN-4s) was employed to conduct initial segmentation on preprocessed images. Following each convolutional layer, batch normalization layers were introduced to expedite network training convergence and enhance the accuracy of the trained model. Subsequently, a fully connected conditional random field (CRF) was integrated to fine-tune the segmentation results, refining the boundaries of pelvic bone tumors and achieving high-quality segmentation. Results: The experimental outcomes demonstrate a significant enhancement in segmentation accuracy and stability when compared to the conventional convolutional neural network bone tumor image segmentation algorithm. The algorithm achieves an average Dice coefficient of 93.31 %, indicating superior performance in real-time operations. Conclusion: In contrast to the conventional convolutional neural network segmentation algorithm, the algorithm presented in this paper boasts a more intricate structure, proficiently addressing issues of over-segmentation and under-segmentation in pelvic bone tumor segmentation. This segmentation model exhibits superior real-time performance, robust stability, and is capable of achieving heightened segmentation accuracy.

Post translational modifications of connexin 43 in ventricular arrhythmias after myocardial infarction.

Ventricular arrhythmias are the leading cause of sudden cardiac death in patients after myocardial infarction (MI). Connexin43 (Cx43) is the most important gap junction channel-forming protein in cardiomyocytes. Dysfunction of Cx43 contributes to impaired myocardial conduction and the development of ventricular arrhythmias. Following an MI, Cx43 undergoes structural remodeling, including expression abnormalities, and redistribution. These alterations detrimentally affect intercellular communication and electrical conduction within the myocardium, thereby increasing the susceptibility to post-infarction ventricular arrhythmias. Emerging evidence suggests that post-translational modifications play essential roles in Cx43 regulation after MI. Therefore, Cx43-targeted management has the potential to be a promising protective strategy for the prevention and treatment of post infarction ventricular arrhythmias. In this article, we primarily reviewed the regulatory mechanisms of Cx43 mediated post-translational modifications on post-infarction ventricular arrhythmias. Furthermore, Cx43-targeted therapy have also been discussed, providing insights into an innovative treatment strategy for ventricular arrhythmias after MI.

Synovia tissue-specific exosomes participate in the dual variation of the osteoarthritis microenvironment via miR-182.

Osteoarthritis (OA) is the most common type of joint disease and the leading cause of chronic disability among older adults. As an important component of the joint, synovium influences the inflammatory and degenerative process of OA. This study found that miRNA 182 (miR-182) in synovium-specific exosomes can modulate inflammation and apoptotic signaling. It also regulated different biological functions to promote the progression of OA. Experiments based on rat OA model and synovium samples from OA patients, we found that synovium-derived miR-182 regulates inflammatory response in the early stage of OA by regulating the expression level of forkhead box O-3 (FOXO3). However, the expression of miR-182 was significantly increased in synovial tissue of advanced OA, which was involved in the apoptotic signal of severe OA. These findings suggest that miR-182 may directly regulate OA progression by modulating FOXO3 production inflammation, and apoptosis.

Olanzapine's effects on hypothalamic transcriptomics and kinase activity.

Olanzapine is a second-generation antipsychotic that disrupts metabolism and is associated with an increased risk of type 2 diabetes. The hypothalamus is a key region in the control of whole-body metabolic homeostasis. The objective of the current study was to determine how acute peripheral olanzapine administration affects transcription and serine/threonine kinase activity in the hypothalamus. Hypothalamus samples from rats were collected following the pancreatic euglycemic clamp, thereby allowing us to study endpoints under steady state conditions for plasma glucose and insulin. Olanzapine stimulated pathways associated with inflammation, but diminished pathways associated with the capacity to combat endoplasmic reticulum stress and G protein-coupled receptor activity. These pathways represent potential targets to reduce the incidence of type 2 diabetes in patients taking antipsychotics.

Sustained exposure to Helicobacter pylori induces immune tolerance by desensitizing TLR6.

Helicobacter pylori (H. pylori, Hp) has been designated a class I carcinogen and is closely associated with severe gastric diseases. During colonization in the gastric mucosa, H. pylori develops immune escape by inducing host immune tolerance. The gastric epithelium acts as the first line of defense against H. pylori, with Toll-like receptors (TLRs) in gastric epithelial cells being sensitive to H. pylori components and subsequently activating the innate immune system. However, the mechanism of immune tolerance induced by H. pylori through the TLR signalling pathway has not been fully elucidated. In this research, we detected the expression of TLRs and inflammatory cytokines in GES-1 cells upon sustained exposure to H. pylori or H. pylori lysate from 1 to 30 generations and in Mongolian gerbils infected with H. pylori for 5 to 90 weeks. We found that the levels of TLR6 and inflammatory cytokines first increased and then dropped during the course of H. pylori treatment in vitro and in vivo. The restoration of TLR6 potentiated the expression of IL-1ß and IL-8 in GES-1 cells, which recruited neutrophils and reduced the colonization of H. pylori in the gastric mucosa of gerbils. Mechanistically, we found that persistent infection with H. pylori reduces the sensitivity of TLR6 to bacterial components and regulates the expression of inflammatory cytokines in GES-1 cells through TLR6/JNK signaling. The TLR6 agonist obviously alleviated inflammation in vitro and in vivo. Promising results suggest that TLR6 may be a potential candidate immunotherapy drug for H. pylori infection.

Tiaogan daozhuo formula attenuates atherosclerosis via activating AMPK -PPARγ-LXRα pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Tiaogan Daozhuo Formula (TGDZF) is a common formulation against atherosclerosis, however, there is limited understanding of its therapeutic mechanism. AIM OF THIS STUDY: To examine the effectiveness of TGDZF in the treatment of atherosclerosis and to explore its mechanisms. MATERIALS AND METHODS: In ApoE-/- mice, atherosclerosis was induced by a high-fat diet for 12 weeks and treated with TGDZF at different doses. The efficacy of TGDZF in alleviating atherosclerosis was evaluated by small animal ultrasound and histological methods. Lipid levels were measured by biochemical methods. The capacity of cholesterol efflux was tested with a cholesterol efflux assay in peritoneal macrophage, and the expression of AMPKα1, PPARγ, LXRα, and ABCA1 was examined at mRNA and protein levels. Meanwhile, RAW264.7-derived macrophages were induced into foam cells by ox-LDL, and different doses of TGDZF-conducting serum were administered. Similarly, we examined differences in intracellular lipid accumulation, cholesterol efflux rate, and AMPKα1, PPARγ, LXRα, and ABCA1 levels following drug intervention. Finally, changes in the downstream molecules were evaluated following the inhibition of AMPK by compound C or PPARγ silencing by small interfering RNA. RESULTS: TGDZF administration reduced aortic plaque area and lipid accumulation in aortic plaque and hepatocytes, and improved the serum lipid profiles of ApoE-/- mice. Further study revealed that its efficacy was accompanied by an increase in cholesterol efflux rate and the expression of PPARγ, LXRα, and ABCA1 mRNA and protein, as well as the promotion of AMPKα1 phosphorylation. Moreover, similar results were caused by the intervention of TGDZF-containing serum in vitro experiments. Inhibition of AMPK and PPARγ partially blocked the regulatory effect of TGDZF, respectively. CONCLUSIONS: TGDZF alleviated atherosclerosis and promoted cholesterol efflux from macrophages by activating the AMPK-PPARγ-LXRα-ABCA1 pathway.

Validation of China Health-Related Outcomes Measures-Cardiovascular Disease.

OBJECTIVES: China Health-Related Outcomes Measures (CHROME) was an initiative aimed at developing a system of preference-based health-related quality of life instruments for China. CHROME-cardiovascular disease (CVD) is a CVD-specific instrument with 14 items developed under this initiative. This study aimed to test the psychometric properties of CHROME-CVD. METHODS: This validation study was conducted using cross-sectional questionnaire survey in China. Eligible patients with CVD were recruited and asked to complete the CHROME-CVD, the EQ-5D-5L, and a CVD-specific nonpreference-based health-related quality of life instrument selected according to the confirmed diagnosis of the patients. Item evaluation, internal consistency, measurement invariance, test-retest reliability, structural validity, and construct validity were tested using classic test theory. Item response theory was used to evaluate item-level performance. RESULTS: A total of 444 patients with CVD (coronary artery disease, n = 276, heart failure, n = 104, angina, n = 33, and atrial fibrillation, n = 16) from 6 provinces in China were enrolled for the validation. Exploratory factor analysis identified 4 factors: chest pain, other symptoms, physical health, and mental and social health. Cronbach's alpha and intraclass correlation coefficient were >0.8. A total of 20 of 26 (76.9%), and 90 of 95 (94.7%) predefined hypotheses were met for convergent and discriminant validities, respectively. No important difference was identified between subgroups of gender and residency. Response options of 10 items were found overlapped based on categorical response curves, which led to modification to 4-level response options. Wording of 3 items were modified by referring wordings of reference instruments. CONCLUSION: The validation of the CHROME-CVD demonstrated generally good psychometric properties. Further validation on the modified CHROME-CVD is needed.

Empagliflozin Induces Vascular Relaxation in Rat Coronary Artery Due to Activation of BK Channels.

Purpose: The aim of this study was to investigate the effects and mechanisms of SGLT2 inhibitor empagliflozin on diabetic coronary function. Methods: A rat diabetic model was established by injection of streptozotocin. Rats in the treated group were administered empagliflozin by gavage and rat coronary vascular tensions were measured after eight weeks. Large conductance calcium activated K+ channel currents were recorded using a patch clamp technique, while human coronary artery smooth muscle cells were used to explore the underlying mechanisms. Results: After incubation with empagliflozin (10, 30, 100, 300, 1000 µmol/L), the Δ relaxation % of rat coronary arteries were 2.459 ± 1.304, 3.251 ± 1.119, 6.946 ± 3.407, 28.36 ± 11.47, 86.90 ± 3.868, respectively. Without and with empagliflozin in the bath solution, BK channel opening probabilities at a membrane potential of +60 mV were 0.0458 ± 0.0517 and 0.3413 ± 0.2047, respectively (p < 0.05, n = 4 cells). After incubation with iberiotoxin, the Δ tensions of rat coronary arteries in the control (Ctrl), untreated (DM), low empagliflozin (10 mg/kg/d)-treated (DM+L-EMPA) and high empagliflozin (30mg/kg/d)-treated (DM+H-EMPA) group were 103.20 ± 5.85, 40.37 ± 22.12, 99.47 ± 28.51, 78.06 ± 40.98, respectively (p < 0.01 vs Ctrl, n = 3-7; p < 0.001 vs DM+L-EMPA, n = 5-7). Empagliflozin restored high glucose-induced downregulation of Sirt1, Nrf2, and BK-ß1, while the effect of empagliflozin disappeared in the presence of EX-527, a Sirt1 selective inhibitor. Conclusion: Empagliflozin has a vasodilation effect on the coronary arteries in a concentration-dependent manner and can activate BK channels via the Sirt1-Nrf2 mechanism.

Chronic Sacral Nerve Stimulation Inhibits Visceral Hypersensitivity in Diarrhea-Predominant Irritable Bowel Syndrome Rats Model.

OBJECTIVE: Sacral nerve stimulation (SNS) is emerging as a novel treatment for irritable bowel syndrome (IBS). However, its effects are limited, and the underlying mechanisms remain largely unknown. MATERIALS AND METHODS: In this study, rats were divided into three groups (n = 12 rats per group): 1) the SNS group; 2) the sham SNS group (the sham group for short); and 3) the control group. The SNS and sham groups were exposed to chronic and acute stress to establish an IBS model. Electrode implantation surgery was performed in rats with the IBS model. The SNS group received electrical stimulation for 30 minutes every day for seven days. Abdominal withdrawal reflex (AWR) was used to evaluate the effect of SNS on visceral sensitivity in diarrhea-predominant IBS (IBS-D) rats. The frequency domain of heart rate variability (HRV) was analyzed to assess the effect of SNS on regulating the autonomic function. The expression of transient receptor potential vanilloid 1 (TRPV1) in the colon, spinal cord, and hippocampus was detected by immunohistochemistry to explore the mechanism of SNS in IBS-D rats. RESULTS: Compared with the sham group, AWR scores were significantly decreased under different gas volumes of stimulation of 0.4, 0.6, and 0.8 ml for rectal distention in the SNS group (all p < 0.05). However, there was no significant difference <1.0 ml between the two groups (p > 0.05). Compared with the sham group, the frequency domain indexes of HRV were significantly altered. Normalized low-frequency power and low frequency-to-high frequency ratio were significantly decreased, and normalized high-frequency power was significantly increased in the SNS group (all p < 0.05). Moreover, the expression of TRPV1 in the spinal cord and colon in the SNS group was significantly decreased compared with the sham group (both p < 0.05). These results suggested that chronic SNS not only improved the visceral sensitivity and autonomic dysfunction but also decreased the expression of TRPV1 in the spinal cord-gut tissue in IBS-D rats. CONCLUSION: Chronic SNS was found to have an inhibitory effect on visceral hypersensitivity in IBS-D rats, providing experimental evidence for its potential clinical application in IBS.

Sodium Danshensu ameliorates cerebral ischemia/reperfusion injury by inhibiting CLIC4/NLRP3 inflammasome-mediated endothelial cell pyroptosis.

Endothelial pyroptosis promotes cerebral ischemia/reperfusion injury (CIRI). Sodium Danshensu (SDSS) has been shown to attenuate CIRI and have anti-inflammatory properties in endothelial cells. However, the mechanism and effect of SDSS on alleviating endothelial pyroptosis after CIRI remains poorly understood. Thus, we aimed to investigate the efficacy and mechanism of SDSS in reducing endothelial pyroptosis. It has been shown that SDSS administration inhibited NLRP3 inflammasome-mediated pyroptosis. As demonstrated by protein microarrays, molecular docking, CETSA and ITDRFCETSA , SDSS bound strongly to CLIC4. Furthermore, SDSS can decrease its expression and inhibit its translocation. Its effectiveness was lowered by CLIC4 overexpression but not by knockdown. Overall The beneficial effect of SDSS against CIRI in this study can be ascribed to blocking endothelial pyroptosis by binding to CLIC4 and then inhibiting chloride efflux-dependent NLRP3 inflammasome activation.

Fine molecular structure and digestibility changes of potato starch irradiated with electron beam and X-ray.

The change of digestibility of starch irradiated with different types from the perspective of fine structure is not well understood. In this work, the change of internal structure, molecular weight and chain-length distribution, helical structure, lamellar structure, fractal structure and digestibility of native and treated potato starch with electron beam and X-ray was analyzed. Two irradiations caused the destruction of internal structure, the disappearance of growth rings and increase of pores. Irradiation degraded starch to produce short chains and to decrease molecular weight. Irradiation increased double helical content and the thickness and peak area of lamellar structure, resulting in the reorganization of amylopectin and increase of structure order degree. The protected glycosidic linkages increased starch resistance to hydrolase attack, thereby enhancing the anti-digestibility of irradiated starch. Pearson correlation matrix also verified the above-mentioned results. Moreover, X-ray more increased the anti-digestibility of starch by enhancing ability to change fine structure.

Dehydrocostus lactone (DHC) promotes osteoblastic differentiation and mineralization through p38/RUNX-2 signaling.

Dysregulation of osteoblastic differentiation is an important risk factor of osteoporosis, the therapy of which is challenging. Dehydrocostus lactone (DHC), a sesquiterpene isolated from medicinal plants, has displayed anti-inflammatory and antitumor properties. In this study, we investigated the effects of DHC on osteoblastic differentiation and mineralization of MC3T3-E1 cells. Interestingly, we found that DHC increased the expression of marker genes of osteoblastic differentiation, such as alkaline phosphatase (ALP), osteocalcin (OCN), and osteopontin (OPN). Additionally, DHC increased the expressions of collagen type I alpha 1 (Col1a1) and collagen type I alpha 2 (Col1a2). We also demonstrate that DHC increased ALP activity. Importantly, the Alizarin Red S staining assay revealed that DHC enhanced osteoblastic differentiation of MC3T3-E1 cells. Mechanistically, it is shown that DHC increased the expression of Runx-2, a central regulator of osteoblastic differentiation. Treatment with DHC also increased the levels of phosphorylated p38, and its blockage using its specific inhibitor SB203580 abolished the effects of DHC on runt-related transcription factor 2 (Runx-2) expression and osteoblastic differentiation, suggesting the involvement of p38. Based on these findings, we concluded that DHC might possess a capacity for the treatment of osteoporosis by promoting osteoblastic differentiation.

A performance degradation model of nitrile butadiene rubber (NBR) O-rings for hydrogen permeation effects under high-pressure.

The integration of molecular chain changes on a microscopic scale to achieve macroscopic performance is crucial in degradation processes concerning O-ring seals. Nonetheless, a comprehensive and compelling mathematical model that can describe molecular chains' material properties and macroscopic material properties simultaneously for O-rings under high-pressure conditions is yet to be established. In this paper, we propose a degradation model based on viscoelasticity and molecular chain statistics for hydrogen permeation. The proposed model aims to establish the relationship between the material molecular chains and macroscopic material properties, with a primary focus on accurately recognizing the performance degradation process of rubber sealing rings. We verify the model's reliability through uniaxial tensile strength experiments and high-pressure hydrogen immersion experiments, respectively. Predictions of the model exhibit favorable conformity with the experimental data concerning the above phenomena. Furthermore, we derive the number of molecular chains and maximum strain of the degradation process. Based on the similarity of the degradation process's descent, it is plausible to speculate that NBR properties' degradation can be characterized by the average number of molecular chains.