Search

Silica fume (SF) is an essential component in ultra-high-performance concrete (UHPC) to compact the matrix, but the nucleus effect also causes rapid hydration, which results in high heat release and large shrinkage. In this paper, the carboxylic agents, including polyacrylic acid and polycarboxylate superplasticizer, were used to surface modify SF to adjust the activity to mitigate hydration at an early time and to promote continuous hydration for a long period. The surface and dispersion properties of modified SF (MSF), as well as the strength and pore structure of UHPC, were studied, and the stability of the modification was also investigated. The results demonstrated that, after treatment, the carboxylic groups were grafted on the SF surface, the dispersion of SF was improved due to the increased negative pentanal of the particle surface and the steric hindrance effect, the early hydration was delayed about 3–5 h, and the hydration heat release was also mitigated. The compressive strength of UHPC with MSF reached a maximum of 138.7 MPa at 3 days, which decreased about 3.7% more than the plain group, while flexural strength varied insignificantly. More pores and cracks were observed in the matrix with MSF, and the hydration degree was promoted with MSF addition. The grafted group on SF fell off under an alkali environment after 1 h. [ABSTRACT FROM AUTHOR]

Introduction: The main goal of our research was to explore the effect of percutaneous intramyocardial septal radiofrequency ablation (PIMSRA) on left atrial (LA) phasic function in hypertrophic cardiomyopathy (HCM). Methods: The study included 13 patients who underwent PIMSRA at our hospital. The function of LA including reservoir, conduit, and booster pump was analyzed and compared before and 6 months after PIMSRA in HCM patients. LA reservoir function parameters contain maximal LA volume, minimal LA volume (LAV min), LA ejection fraction (LAEF), LA expansion index (LAEI), and reservoir strain; LA conduit function includes LA volume before atrial systole, LA passive volume, LA passive ejection fraction, and conduit strain; LA booster function involves LA booster volume, LA active ejection fraction, and LA contraction strain. Additionally, 20 healthy controls were selected to compare the LA function of HCM patients. Results: The preoperative LA reservoir and conduit function in HCM patients were significantly impaired compared with the control group, while the change in booster pump function was not obvious. HCM patients at 6 months after PIMSRA had remarkably enhanced reservoir and conduit functions which were manifested by lower LAV min, higher LAEF, LAEI, reservoir, and conduit strain than before the operation, and the differences among these parameters between patients after PIMSRA and the healthy control group were not significant. However, with regard to LA contraction function, there was no significant improvement at 6 months after PIMSRA compared with before operation. Conclusion: PIMSRA is effective in the amelioration of LA reservoir and conduit function in patients with HCM but not in a marked improvement of LA contraction function in these individuals in short term. [ABSTRACT FROM AUTHOR]

In view of the low utilization rate of hydrogen, high energy consumption, narrow use scope and other defects of the way of hydrogen supply commonly used in fuel cell at present, a rapid prototyping development technique for common rail hydrogen injection system is proposed based on MotoTron platform. By tuning the control parameters, reasonable steady-state error of hydrogen output and dynamically adjustable exit flow rate are realized. The results show that the technique proposed can enable evener distribution of hydrogen at fuel cell anode, raise the utilization rate of hydrogen and extend the lifespan of fuel cell, laying a foundation for subsequent vehicle development. [ABSTRACT FROM AUTHOR]

Purpose: Kidney transplantation (KT) has the potential to reverse the cardiac changes caused by end-stage renal disease, and it may be inaccurate to analysis the left ventricular function by conventional echocardiography due to afterload. This study aimed to investigate the utility of pressure strain loops (PSLs) in evaluating left ventricular performance in patients underwent KT., Methods: We enrolled 60 patients with end-stage renal disease who underwent KT between January 2022 and July 2023, and 60 healthy controls with a similar distribution of gender and age to the patients. All participants underwent conventional echocardiography and three-dimensional speckle tracking echocardiography (3D-STE). Long axis, short axis, and four cavity images were collected and cardiac parameters were measured. The echocardiographic changes of cardiac structure and function of all patients before KT and about 12 months after KT were recorded. Left ventricular myocardial work parameters were acquired by PSLs, including the global work index (GWI), global constructive work (GCW), global wasted work (GWW), global work efficiency (GWE) and global longitudinal strain (GLS). In addition, the correlation between PSLs and clinical data were explored., Results: Compared with controls, the conventional echocardiographic parameters, myocardial function indicators GWI and GCW appeared no difference in post-KT group, while the GWE and GLS decreased ( p  < 0.05), and the GWW increased ( p  < 0.05). Compared with pre-KT, the GLS, GWI, GCW and GWE increased in post-KT group, while the GWW decreased (all p  < 0.05). The above indicators were correlated with left ventricular GLS and left ventricular ejection fraction., Conclusion: PSLs were more sensitive than traditional echocardiographic indicators in detecting changes in myocardial work and predicting left ventricular myocardial damage. This indicator could quantitatively evaluate myocardial work and provide a new and reliable non-invasive reference for clinical diagnosis and treatment of patients underwent KT., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 Han, Wang, Wang, He, Song, Wang, Zhao, Chen, Sun and Zhang.)

Toll-like receptor 4 (TLR4) is a key modulator in many inflammation-related diseases. Polymorphisms in the TLR4 gene may alter TLR4 expression and affect the extent and severity of coronary artery disease (CAD). We analyzed 3 polymorphisms of TLR4 in 607 Chinese subjects who underwent coronary arteriography. Blood samples were collected to identify the polymorphisms. We evaluated the relationships between the polymorphisms and the number of vessels involved in coronary stenosis, Gensini scores, and Duke prognostic scores. We found that rs11536889 was associated with an increased risk of 3-vessel disease. When subjects with 3-vessel disease were compared to subjects with nonsignificant CAD, rs11536889 variant genotypes were associated with an increased risk of 3-vessel disease (GC/CC vs. GG: OR=2.06, 95%CI=1.21-3.51). When subjects with 3-vessel disease were compared to subjects with 1-vessel disease, rs11536889 variant genotypes were associated with an increased risk of 3-vessel disease (GC vs. GG: OR=2.14, 95%CI=1.20-3.79; GC/CC vs. GG: OR=2.06, 95%CI=1.20-3.54). When subjects with 3-vessel disease were compared to subjects with non-3-vessel disease, rs11536889 variant genotypes were associated with an increased risk of 3-vessel disease (GC vs. GG: OR=1.76, 95%CI=1.12-2.75; GC/CC vs. GG: OR=1.83, 95%CI=1.19-2.82). The TLR4 rs11536889 polymorphism was also related to Gensini score (P=0.02). The Gensini score was higher in subjects with the variant CC and GC/CC genotype than in subjects with the wild GG genotype (61.28± 1.84 and 57.64±34.82 vs. 51.27±34.57). Our results demonstrate that TLR4 rs11536889 polymorphism is a novel genetic factor in the development of CAD, influencing the extent and severity of CAD.