Dynamic Response of a Combined Isolation Based Mega-Substructure under Bidirectional Near-Fault Ground Motions

A typical megaframe structure has a high lateral stiffness and is excellent for high-rise structures. However, this high stiffness can lead to poor seismic response of a structure. Seismic isolation technology is a mature and cheap vibration control method that is used for vibration reduction in megaframes. This paper introduces a megaframe structure based on substructure combined isolation. The structure consists of two parts. The main body is a megaframe, and the substructure is the subframe with the combined isolation layer arranged at the bottom of the subframe. The seismic performance of this structure system was evaluated by performing shaking table tests of two megaframe model structures. The responses of the deformation, acceleration, and shear of the structure were measured. The dynamic behaviors of the structure with or without the combined isolation layer when exposed to single and bidirectional near-fault and far-fault ground motions with different peak values were investigated. The results showed that the combined isolation layer can reduce the bidirectional seismic response of the main frame and subframe. The acceleration, base shear, and displacement responses had similar vibration reduction trends for the two model structures, and the structural responses under bidirectional earthquake were generally greater than that under a single directional earthquake. The near-fault pulse effect increased the seismic response of the structure. The increase of the predominant period of ground motion also increased the seismic response of the structure

Tie strength, absorptive capacity and innovation performance in Chinese manufacturing industries

Purpose In innovation networks, firm innovation performance is affected by external tie strength and internal knowledge absorptive capacity. This study aims to empirically examine the path relationship between tie strength, absorptive capacity and firm innovation performance in Chinese manufacturing industries, thus enhance our understanding on the mechanism between innovation network and innovation performance. Design/methodology/approach The authors have conducted a survey among Chinese manufacturers in four industries (textile and garment, household appliance, IT and electronics and motor vehicle assemblers) that are located in North, East, Central and South China, respectively, with a valid response from 278 manufacturers. Structural equation model is used to analyze the results. Findings This study demonstrates that in Chinese Manufacturing industry, tie strength is positively related to innovation performance. The authors also find that absorptive capacity has a positive impact on innovation performance and it mediates the relationship between tie strength and innovation performance. Then, the authors analyze the effect of ownership, industry and sub-region, and the results show that in private firms and traditional manufacturers, and the firms located in North and Eastern China, tie strength has no direct effect on innovation outcomes, but it can influence innovation indirectly through absorptive capacity. Originality/value This study further supports that in Chinese guanxi culture, strong ties with other innovation partners can improve the firm’s absorptive capacity and thus improve innovation performance. The results also suggest that a firm’s absorptive capacity has a significant mediating effect on the relationship between tie strength and innovation performance

Numerical Analysis of Mechanical Behavior of Self-Centering Joint between CFDST Column and RC Beam

The existing connection between the concrete-filled double steel tubular (CFDST) column and the reinforced concrete (RC) beam is difficult to repair and reuse after damage. In this paper, a self-centering joint between the CFDST column and the RC beam is proposed. The self-centering of the joint is realized by prestressed steel strands, and the energy dissipation is realized by friction. The overall purpose of the research is to analyze the influence of steel strand and friction on the mechanical behavior of the joint. By comparing the envelope curve and the restoring force model of a numerical joint model with theoretical values, accuracy of the numerical model was verified. Then, joints with different parameters, including the friction, prestress of steel strands, and ratio of the resisting moment provided by steel strands to the resisting moment provided by friction in the opening moment of joints, were numerically analyzed. The results showed that the joints with greater friction and prestress of steel strands had higher bearing capacity. Increasing the friction could increase the energy dissipation capacity of the joint, but it would increase the residual deformation of the joint. To reduce residual deformation, the prestress of steel strands should be increased. When the resultant force of the pretension of steel strands was greater than friction, the steel head could be kept pressed on the connecting block, making the stress changes of steel strands and the self-centering performance of the joint stable

Al Alloys and Casting Processes for Induction Motor Applications in Battery-Powered Electric Vehicles: A Review

With the rapid expansion of battery-powered electric vehicles (BEVs) in the automotive industry, research interest in lightweight Al alloys as well as their casting processes and applications has increased considerably. The substitution of castable aluminum alloys with superior strengths and electrical conductivity for copper reduces the weight and size of electric induction motors, and improves the energy efficiency and driving range of the BEVs. The present article was intended to give a general introduction into the common cast Al aluminum alloys and their relevant processes, as well as to motivate the development of high strength and conductive Al alloys for the practical realization of Al applications in the motors of the BEVs. A number of cast alloy systems containing Cu, Si, Ni, Mg, Fe, and Ti were evaluated, in comparison to nanostructured wrought Al alloys. The conventional casting processes suitable for Al alloys, high pressure die casting, squeeze casting, and sand casting were described. Strengthening mechanisms including solid solution strengthening, precipitation strengthening, dislocation accumulation strengthening, and grain boundary strengthening were presented. The phenomenon of electrical conduction for Al alloys was outlined. The mechanical properties and electrical properties of the recently developed Al alloys for casting and deformation processes were comprehensively listed and critically reviewed in association with microstructural characteristics

NEK2 contributes to radioresistance in esophageal squamous cell carcinoma by inducing protective autophagy via regulating TRIM21

Abstract Background Radiotherapy (RT) has been identified as a vital treatment for esophageal squamous cell carcinoma (ESCC), while the development of radioresistance remains a major obstacle in ESCC management. The aim of this study was to investigate the effect of NIMA-related kinase 2 (NEK2) on radioresistance in ESCC cells and to reveal potential molecular mechanisms. Methods Human esophageal epithelial cells (HEEC) and human ESCC cell lines were obtained from the Research Center of the Fourth Hospital of Hebei Medical University (Shijiazhuang, China). Cell Counting Kit-8 (CCK-8) and flow cytometry assays were applied to assess the proliferation ability, cell cycle, apoptosis rates, and ROS production of ESCC cells. The colony-forming assay was used to estimate the effect of NEK2 on radiosensitivity. Autophagy was investigated by western blotting analysis, GFP-mRFP-LC3 fluorescence assay, and transmission electron microscopy (TEM). Results In the present study, our results showed that NEK2 was associated with radioresistance, cell cycle arrest, apoptosis, ROS production, and survival of ESCC. NEK2 knockdown could significantly inhibit growth while enhancing radiosensitivity and ROS production in ESCC cells. Interestingly, NEK2 knockdown inhibited ESCC cell autophagy and reduced autophagic flux, ultimately reversing NEK2-induced radioresistance. Mechanistically, NEK2 bound to and regulated the stability of tripartite motif-containing protein 21 (TRIM21). The accumulation of NEK2-induced light chain 3 beta 2 (LC3B II) can be reversed by the knockdown of TRIM21. Conclusion These results demonstrated that NEK2 activated autophagy through TRIM21, which may provide a promising therapeutic strategy for elucidating NEK2-mediated radioresistance in ESCC

DataSheet_1_Minimal residual disease guided radical chemoradiotherapy combined with immunotherapy after neoadjuvant immunochemotherapy followed by adjuvant immunotherapy for esophageal squamous cell cancer (ECMRD-001): a study protocol for a prospective cohort study.doc

IntroductionFor locally advanced, inoperable esophageal cancer, concurrent chemoradiotherapy (CCRT) becomes the norm. Combining immunotherapy with radiotherapy has been shown to improve efficacy. Circulating tumor DNA (ctDNA) is a strong predictor of effectiveness and tumor recurrence and is indicative of minimal residual disease (MRD). Patients with inoperable stage II-III esophageal squamous cell carcinoma (ESCC) are enrolled in the ECMRD-001 trial to evaluate changes in MRD status before and after CCRT combined with immunotherapy and adjuvant immunotherapy following neoadjuvant immunochemotherapy.Methods and analysisThe ECMRD-001 trial is a prospective cohort study. Eligible patients will receive radical concurrent chemoradiotherapy combined with immunotherapy after neoadjuvant immunochemotherapy, followed by adjuvant immunotherapy for at least one year. Follow-up will be up to three years. MRD-related blood and tissue samples and T-cell immunohistobank related blood and tissue samples collected before, during and after treatment and follow-up will be grouped into sample collection time points. The relationship between MRD status at different time points and treatment efficacy is the primary outcome. Correlation between MRD status and immune microenvironment, radiotherapy dose, and tumor recurrence are the secondary outcomes. Examination of ctDNA mutations is the exploratory outcome.DiscussionctDNA-based MRD may be a potential predictive marker for the efficacy and tumor recurrence of inoperable ESCC patients. Elevated ctDNA-MRD may predict tumor recurrence earlier than imaging. ctDNA-based MRD analysis and ctDNA-based MRD guided diagnosis and treatment should be implemented into clinical practice to improve efficacy and reduce tumor recurrence of inoperable stage II-III ESCC.Trial registrationThe ECMRD-001 study has been registered at ClinicalTrials.gov as NCT05952661 (July 19, 2023), https://classic.clinicaltrials.gov/ct2/show/NCT05952661.</p

Long-term Prognosis Analysis and Influencing Factors of Concurrent Chemotherapy and Radio-therapy for Cervical and Upper Thoracic Esophageal Squamous Cell Carcinoma

Background The incidence of cervical and upper thoracic esophageal cancer is relatively low, with difficulties and controversies of mode in treatment, lack of convenient and accurate prognostic biomarkers, and poor overall prognosis. Objective To investigate the long-term prognosis of patients with cervical and upper thoracic esophageal squamous cell carcinoma under concurrent chemotherapy and radio-therapy (CCRT) . Methods Patients with cervical and thoracic upper esophageal cancer who received CCRT in the Department of Radiotherapy of the Fourth Hospital of Hebei Medical University from January 2013 to December 2017 were selected as the research subjects. General data, Eastern Cooperative Oncology Group (ECOG) score, tumor site, tumor length, TNM stage, radiotherapy dose, irradiation mode, chemotherapy regimen, toxic and side effects were collected by electronic medical record system, and neutrophil to lymphocyte ratio (dNLR) was calculated. The patients were divided into the dNLR&lt;2.15 group (64 cases) and dNLR≥2.15 group (42 cases) according to dNLR. The patients were followed up, radiotherapy was reviewed once every 3 months for 1 year, once every 6 months for 2 to 5 years, and once every 1 year after 5 years, and overall survival (OS), progression-free survival (PFS), local relapse-free survival (LRRFS), and distant metastasis-free survival (DMFS) were collected. Survival curves of OS, LRRFS and DMFS were plotted by Kaplan-Meier method. The single factor analysis of OS, PFS, LRRFS and DMFS was performed by Log-rank test. Multivariate Cox proportional hazard regression model was used to explore the influencing factors of OS, PFS, LRRFS and DMFS. Results As of the last follow-up, the OS rates at 3, 5 and 7 years were 55.7%, 43.0% and 37.8%, with a median OS of 47.5〔95%CI (29.4, 65.6) 〕months; the rates of PFS at 3, 5 and 7 years were 45.3%, 37.7% and 31.1%, with a median PFS of 30.7〔95%CI (21.1, 40.3) 〕months; the LRRFS rates in 3, 5 and 7 years were 50.9%, 41.4% and 33.5%, with a median LRRFS of 43.5〔95%CI (21.6, 65.4) 〕months; the DMFS rates at 3, 5 and 7 years were 49.1%, 38.6% and 34.4%, with a median DMFS of 34.7〔95%CI (20.7, 48.7) 〕months. Multivariate Cox proportional hazard regression analysis showed that TNM stage and irradiation mode were influencing factors of OS, PFS, LRRFS and DMFS (P&lt;0.05), gender was an influencing factor of LRRFS (P&lt;0.05), and dNLR was an influencing factor of PFS and DMFS (P&lt;0.05). There were 10 cases, 25 cases, 32 cases, 9 cases and 11 cases of grade 2 and above acute radiation pneumonitis, acute radiation esophagitis, leukopenia, anemia and thrombocytopenia, respectively. Conclusion The long-term prognostic survival outcome of CCRT for cervical and upper thoracic esophageal squamous cell carcinoma was satisfactory and well tolerated. Local recurrence was the main failure pattern. Elective lymphatic drainage irradiation can significantly improve the prognosis of patients, which can be promoted clinically and dNLR has a predictive effect on long-term survival

Wnt/PCP pathway regulates the migration and neural differentiation of mesenchymal stem cells in vitro

Introduction. Mesenchymal stem cells (MSCs) are an excellent donor graft source due to their potential for self-renewal and multidirectional differentiation. However, the potential mechanisms involved in MSC homing and neural differentiation are still unclear. The purpose of this study was to explore the effects of a chemokine, SDF-1a, and Wnt3a ligand on rat MSCs’ migration and b-mercaptoethanol (BME)-induced neural differentiation of MSCs. Materials and methods. MSCs were isolated from rat bone marrow and cultured in vitro to passage 3. Scratch tests and transwell assays were used to estimate the effects of SDF-1a (25 ng/mL) and Wnt3a (10 ng/mL) on the migration of MSCs. The expression of Wnt/PCP pathway proteins RhoA, c-Jun, ATF2, and Wnt3a were assessed by Western blot. The 5 mM BME-induced neural differentiation of MSCs was determined by immunofluorescence to detect neuron- and astrocyte-specific markers such as nestin, GFAP, and Olig2. Results. Wnt3a promoted the migration ability of MSCs and regulated the expression of RhoA, c-Jun, and ATF2 proteins. MSCs could differentiate into neural stem cells and astrocytes. Wnt3a enhanced BME induced neurogenesis in MSCs by increasing the protein expression of RhoA, c-Jun, and Wnt3a. Conclusions. The present study demonstrated that the Wnt/PCP pathway promotes migration and neural differentiation of rat MSC