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The cracking of concrete linings in the channel of the Yuzhou section of the South-to-North Water Diversion Project in Henan Province poses a threat to the structural safety of the project and the water quality environment. To solve this problem, the mixing ratio of non-dispersible underwater concrete (NUC) was optimized, the bond strength of new and old concrete was measured, and an underwater repair methodology of the linings was proposed using NUC. The results showed that adding 2.5% of UWB-Ⅱ-type anti-dispersant resulted in NUC with a 28-day underwater compressive strength of 25.1 MPa and a strength ratio of 0.9 between land and water. The effects of water–cement ratio, anti-dispersant dosage, and fly ash dosage on the performance of the NUC were revealed through experiments, and the mix ratio of NUC was optimized. Bond strength measurement at the interface between the NUC and old concrete was tested using the straight shear test. The test results showed that the bond strength between non-dispersible concrete and ordinary concrete was higher than that between ordinary concrete of the same strength grade. Through an analysis of the ionic composition of the water, it was verified that the NUC did not affect the water quality. Therefore, NUC can provide a reference for the underwater repair of the lining panel of the South-to-North Water Diversion Project.

Using glucose as the reducing agent, the nano-silver-graphene composite material (Ag/GR) was synthesized in situ by electroless plating, the structural morphology of the material was characterized and analyzed by X-ray diffraction (XRD), X-ray energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and Fourier infrared spectrometry (FTIR). The results show that the loading morphology of silver on the graphene surface is the single state that meets the expectation. The average particle size of AgNPs is about 21 nm. At the same time, the electrochemical response of ascorbic acid (AA) on Ag/GR/GCE electrochemical sensors was studied using the electrochemical test methods of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV). The electrochemical test results show that the Ag/GR composite has the highest response electrochemical signal of 212.9 μA and the lowest resistance of charge transfer of 90.5 Ω. The peak current is about twice that of the graphene electrode (110 μA) and about five times that of the glassy carbon electrode (42.5 μA). Due to the good synergistic effect of AgNPs and graphene, it has obvious electrocatalytic activity for AA. And the anode peak current and concentration show positive correlation linear change trend in the range of 5-120 μmol/L. However, the anode peak current of AA is highly correlated with the natural logarithm of the concentration range from 50 μmol/L to 120 μmol/L. The low limits of detection is 0.06 μmol/L.

Thermoplastic composite materials are widely used in automobile, aerospace and military fields due to their advantages of high impact toughness, recyclability and excellent environmental adaptability. However, the high viscosity of the thermoplastic resin after melting makes it difficult to impregnate the fiber adequately. As the intermediate material of composite materials, the preparation of prepreg has been relatively mature. The fibers in the prepreg have been impregnated with resin, so the composite material prepared by the prepreg has fewer voids. The preparation method of thermoplastic prepreg and analysis of the advantages and disadvantages of various preparation methods were introduced in this paper, including solution impregnation, melt impregnation, powder impregnation, film stacking lamination, commingled yarns and reactive of chain growth impregnation. The impregnation mechanism of melt infiltrated fibers was described and some research results of impregnation mechanism were summarized. The effects of parameters such as immersion temperature, immersion pressure and traction speed on the properties of prepreg were discussed. Finally, the main problems and the development direction in the production of prepreg were summarized. In the future, methods such as multidisciplinary integration, fiber and resin modification and computer simulation of the impregnation process can be used to promote the industrial development of thermoplastic prepreg.

Reactive powder concrete-filled steel tube (RPC-FST) is a critical supporting component of large-span, high-rise, and heavy-load structures. The collapse of RPC-FST may occur under explosive load. Therefore, investigation of the dynamic response is essential for understanding the mechanisms of collapse. In this article, the numerical simulation of reactive powder concrete (RPC) adopted the modified Holmquist–Johnson–Cook (HJC) model and the modified Karagozian and Case (K&C) model. The dynamic response of RPC-FST columns under explosive load is analyzed based on arbitrary Lagrange–Euler (ALE) method. The proposed model is verified by experimental results. Results show that the modified HJC model and modified K&C model can be applied to simulate the dynamic response of RPC-FST columns under explosive load. As compared with the modified HJC model, the modified K&C model has more accurate results. This phenomenon mainly accounts for the lack of ultimate strain of RPC (EFMIN). To analyze the reliability sensitivity of RPC-FST, an efficient probability analysis method is proposed based on the Kriging model and Monte Carlo simulation (MCS). The proposed method considers five nonlinear factors, including weight and distance of TNT, height and section diameter of RPC-FST, and steel tube thickness. Finally, the sensitivity of each factor is evaluated. Results show that TNT weight greatly influences the reliability of the RPC-FST, followed by TNT distance, RPC-FST height, RPC-FST section diameter, and steel tube thickness. In addition, the RPC-FST dynamic response analysis method based on the Kriging model and MCS can improve the calculation efficiency by more than 200 times compared with the ALE method.

Reactive power concrete (RPC) possesses high compressive strength, toughness, and durability, and it is increasingly being used in important buildings. The column is an important load-bearing member of a building, and its failure under blast loading results in building collapse. Based on these attributes, the dynamic response and the degree of damage to the RPC column are critical in assessing building performance. Due to the lack of methods, the progress of the study is relatively slow. In order to solve these issues, the dynamic response of the RPC column is studied based on the equivalent single-degree-of-freedom method and P-I curve in this paper. During the model validation phase, the deformation of the RPC column predicted using the ESDOF approach correlates well with the explosion simulation and test results. The P-I curves of the typical RPC column were also determined, and some data were analyzed to evaluate the influence of different key parameters, such as slenderness ratio, cross-sectional dimension, and axial compression ratio. The results show that the RPC column is susceptible to shear, bending, and bending-shear failure in the impulse load region, quasi-static load region, and dynamic load region, respectively. The cross-sectional dimension and slenderness ratio exhibit the greatest influence on P-I curves among the five parameters. With the increasing cross-sectional dimension and slenderness ratio, the overpressure asymptote of bending response increases by 4.2 times and decreases by about 57.3%. Furthermore, combined with the P-I curve features, it is found that reasonably increasing the cross-sectional dimensions and RPC strength could simultaneously improve the comprehensive anti-blast performance of RPC columns. This study was carried out to obtain the effect of the five parameters mentioned above on the degree of damage under different blast loading, which can provide a valuable reference for the dynamic response of RPC columns.

The safety and cost of structures composed of concrete-filled steel tube (CFST) frame-steel plate shear walls (SPSWs) with two-side connections are governed by the seismic performance. The response modification factor R and displacement amplification factor Cd are important seismic performance factors. In this paper, nonlinear seismic responses of 10-story, 15-story, and 20-story CFST frame-SPSWs (CFST-SPSWs) are studied. A nonlinear finite element model which includes both material and geometric nonlinearities is developed using the finite element software OpenSees for this study. The accuracy of model was validated by comparing with experimental results. Nonlinear seismic analysis shows that CFST-SPSWs, in high seismic region, behave in a stable and ductile manner. Also, R and Cd of CFST-SPSWs were evaluated for the structure models using incremental dynamic analysis (IDA), and the average values of 3.17 and 3.05 are recommended, respectively. The recommended R value is greater than the value (2.8) in the “Chinese Code for seismic design of buildings” for composite structures, indicating the code is conservative. The structural periods provided by current code are generally lower than the periods calculated by finite element analysis. Research results show that R and Cd increase with increasing story number, span number, and structural period. Ductility reduction factor Rμ increases with increasing span number and decreasing story number. Overstrength factor Rs increases with increasing story number and decreasing span number.

Results from mechanical tests on thirteen reactive powder concrete- (RPC-) filled circular steel tube (RFCT) columns under monotonic and cyclic axial loading are presented in this paper. The test variables include monotonic and cyclic loadings, confinement coefficient, and diameter of the steel tube. The test results show that the envelope curves of specimens under cyclic loading were similar to the load-deformation curves of the specimens under monotonic loading. Confinement coefficient had a significant influence on the failure modes of RFCT columns. With an increase in confinement coefficient of 0.53 to 0.98, the failure mode transformed from shear failure to compressive failure for specimens under monotonic and cyclic loading. In the elastic stage, no confining effect was provided by the steel tube to the RPC since Poisson’s ratio of steel was larger than the transverse deformation coefficient of RPC. Beyond the elastic stage, the axial compressive strength and ultimate strain of RPC increased significantly due to the confining effect when compared to unconfined RPC. Stress of the steel tube and RPC was investigated by using an elastic-plastic analytical model. Before yielding of the steel tube, stress development in the tube was faster in the longitudinal direction than in the hoop direction. The results of the experiment indicate that the compressive strength of RPC could be predicted by Mander’s model for confined concrete. Based on Mander’s model, an equation is extended to calculate the axial compressive strength of RFCT columns, and the predicted results are in good agreement with the test results. Based on comparative analysis of 180 RFCT columns axial compressive tests, the equation given by EC4 considering the confinement effect can be applied to predict the compressive strength of RFCT columns.

Abstract Background Increased Al concentration causes reduction of mitotic activity, induction of nucleolar alteration, increase of the production of ROS and alteration of several antioxidant enzyme activities in plant cells. Allium cepa is an excellent plant and a useful biomarker for environmental monitoring. Limited information is available about the effects of Al on nucleoli, antioxidant enzyme system, contents of MDA and soluble protein in A. cepa. Therefore, we carried out the investigation in order to better understand the effects of Al on the growth, nucleoli in root tip cells and selected physiological and biochemical characters. Results The results showed that the root growth exposed to 50 μM Al was inhibited significantly. 50 μM Al could induce some particles of argyrophilic proteins scattered in the nuclei and extruded from the nucleoli into the cytoplasm. The nucleolus did not disaggregate normally and still remained its characteristic structure during metaphase. Nucleolar reconstruction was inhibited. 50 μM Al induced high activities of SOD and POD in leaves and roots significantly (P < 0.05) when compared with control, whereas the level of CAT was low significantly (P < 0.05). At 50 μM Al the content of MDA in leaves was high significantly (P < 0.05) at 9th day and in roots increased (P < 0.05) with prolonging the treatment time during 6-12 days. The soluble protein content in leaves treated with 50 μM Al was high significantly (P < 0.05) at 6th day and increased with prolonging the treatment time. Conclusions We suggest that variations in nucleoli and the alterations of antioxidant enzyme activities, MDA and soluble protein contents in Allium cepa can serve as useful biomarkers, which can provide valuable information for monitoring and forecasting effects of exposure to Al in real scenarios conditions. Among the antioxidant enzymes SOD and POD appear to play a key role in the antioxidant defense mechanism under Al toxicity condition. Data from MDA concentration show that Al indirectly produces superoxide radicals, resulting in increased lipid peroxidative products and oxidative stress.

Abstract Background In rats, esophagogastroduodenal anastomosis (EGDA) without concomitant chemical carcinogen treatment leads to gastroesophageal reflux disease, multilayered epithelium (MLE, a presumed precursor in intestinal metaplasia), columnar-lined esophagus, dysplasia, and esophageal adenocarcinoma. Previously we have shown that columnar-lined esophagus in EGDA rats resembled human Barrett's esophagus (BE) in its morphology, mucin features and expression of differentiation markers (Lab. Invest. 2004;84:753–765). The purpose of this study was to compare the phenotype of rat MLE with human MLE, in order to gain insight into the nature of MLE and its potential role in the development of BE. Methods Serial sectioning was performed on tissue samples from 32 EGDA rats and 13 patients with established BE. Tissue sections were immunohistochemically stained for a variety of transcription factors and differentiation markers of esophageal squamous epithelium and intestinal columnar epithelium. Results We detected MLE in 56.3% (18/32) of EGDA rats, and in all human samples. As expected, both rat and human squamous epithelium, but not intestinal metaplasia, expressed squamous transcription factors and differentiation markers (p63, Sox2, CK14 and CK4) in all cases. Both rat and human intestinal metaplasia, but not squamous epithelium, expressed intestinal transcription factors and differentiation markers (Cdx2, GATA4, HNF1α, villin and Muc2) in all cases. Rat MLE shared expression patterns of Sox2, CK4, Cdx2, GATA4, villin and Muc2 with human MLE. However, p63 and CK14 were expressed in a higher proportion of rat MLE compared to humans. Conclusion These data indicate that rat MLE shares similar properties to human MLE in its expression pattern of these markers, not withstanding small differences, and support the concept that MLE may be a transitional stage in the metaplastic conversion of squamous to columnar epithelium in BE.

Private enterprises are important due to their innovation-driven development strategies. There are many private entrepreneurs in China who have experience working in state-owned enterprises (SOEs), and how entrepreneurs' SOE work experience affects enterprise innovation investment has not yet been sufficiently studied. Based on imprinting theory and using data from a survey of private enterprises in China, our study confirms that private entrepreneurs' SOE work experience promotes enterprise innovation investment. Mechanism tests suggest that political connections and policy perceptions are mediating mechanisms. Entrepreneurs' educational background reinforces the mediating roles. This paper enriches the research on imprinting theory and enterprise innovation. [ABSTRACT FROM AUTHOR]

Background: Mastectomy (MT) and breast conservation surgery (BCS) are two common surgical options for the treatment of locally advanced breast cancer (LABC). Neoadjuvant chemotherapy (NACT) is frequently administered before surgery to shrink tumors and improve surgical outcomes. However, there is a lack of consensus on the optimal surgical approach after NACT and its impact on survival outcomes. Objective: This meta-analysis aims to compare the survival outcomes between MT and BCS in patients treated with NACT. Method: A PRISMA selection was used to identify studies across electronic database such as PubMed, and Cochrane Library from inception until 11th July, 2023. A total of 10 comparative studies involving a total of 5018 patients were included. Among them, 2898 patients underwent MT while 2120 underwent BCS after receiving NACT. The outcomes assessed were the 5-year overall survival (OS) and 5-year disease-free survival (DFS). The data from the included studies were pooled, and odds ratios (OR) with 95% confidence intervals (CI) were calculated to evaluate the differences between MT and BCS in terms of survival outcomes. Prospero: CRD42024496831. Result: The meta-analysis revealed that patients who underwent MT after NACT had a higher 5-year OS compared to those who underwent BCS (OR 2.68, 95% CI [2.19-3.28; p < 0.00001]). Additionally, the 5-year DFS was significantly better for patients who underwent MT (OR 3.11, 95% CI [1.80-5.38; p < 0.0001]). Conclusion: MT after NACT may be associated with better 5-year OS and DFS compared to BCS. [ABSTRACT FROM AUTHOR]