Search

In this paper, the steel structure system of the assembled building is studied, the box modular building stiffness matrix reduction is proposed, and the calculation method of nodal stiffness matrix reduction is proposed based on the concept of nodal degrees of freedom coalescence and substructure to make full use of the repeatability of the box unit to reduce the order of the matrix equilibrium equation. Then, an engineering profile and a comparison of the calculation results of reaction spectrum analysis are carried out for the assembled steel structure system, and studies on the distribution of overturning moments between the frame and core and the distribution of shear forces between the core and the frame are carried out. Lastly, the assembled steel structure system is examined for damage analysis. The results show that the total overturning moment between the box-type modular structure and the conventional structure differs by 5979.6 kN·m and 2.67% in the X-direction and by 4694 kN·m and 2.18% in the Y-direction. The quality and safety of construction projects can be guaranteed more reliably with the help of this study.

Calcium ions (Ca2+) play crucial roles as second messengers in living cells and are associated with the onset and development of chronic brain diseases, including epilepsy. Dynamic and real‐time imaging of extracellular calcium levels ([Ca2+]ex) in the brain holds great potential for identifying disease foci. Magnetic resonance imaging (MRI) is a powerful non‐invasive tool for Ca2+ imaging with unlimited depth penetration. However, current available Ca2+ MR sensors lack the sensitivity to monitor small [Ca2+]ex alterations associated with chronic brain diseases in vivo. In this study, a highly sensitive Ca2+‐dependent T2‐T1 switchable magnetic nanosensor is reported, consisting of Ca2+‐specific ligands engineered near‐paramagnetic iron oxide nanoparticles. Surface ligand modifications can be adjusted to regulate the interaction energy between sensors and Ca2+, allowing for customizable response range and sensitivity to fulfill the in vivo imaging requirements. The optimized sensors enable non‐invasive visualization of early‐stage seizure focus in mice undergoing epilepsy. [ABSTRACT FROM AUTHOR]

Ultra‐high field (UHF) magnetic resonance imaging (MRI) has emerged as a focal point of interest in the field of cancer diagnosis. Despite the ability of current paramagnetic or superparamagnetic smart MRI contrast agents to selectively enhance tumor signals in low‐field MRI, their effectiveness at UHF remains inadequate due to inherent magnetism. Here, we report a ligand‐mediated magnetism‐conversion nanoprobe (MCNP) composed of 3‐mercaptopropionic acid ligand‐coated silver‐gadolinium bimetallic nanoparticles. The MCNP exhibits a pH‐dependent magnetism conversion from ferromagnetism to diamagnetism, facilitating tunable nanomagnetism for pH‐activatable UHF MRI. Under neutral pH, the thiolate (−S−) ligands lead to short τ′m and increased magnetization of the MCNPs. Conversely, in the acidic tumor microenvironment, the thiolate ligands are protonated and transform into thiol (−SH) ligands, resulting in prolonged τ′m and decreased magnetization of the MCNP, thereby enhancing longitudinal relaxivity (r1) values at UHF MRI. Notably, under a 9 T MRI field, the pH‐sensitive changes in Ag−S binding affinity of the MCNP lead to a remarkable (>10‐fold) r1 increase in an acidic medium (pH 5.0). In vivo studies demonstrate the capability of MCNPs to amplify MRI signal of hepatic tumors, suggesting their potential as a next‐generation UHF‐tailored smart MRI contrast agent. [ABSTRACT FROM AUTHOR]

Operative therapy for superficial esophagus carcinoma is the main way to treat the disease. Endoscopic excision of lesions in the esophagus has become an alternative to surgical treatment for patients with esophageal carcinoma. To overcome the disadvantages of endoscope mucosa excision (EMR), an endoscopic submucosal dissection (ESD) technique has been developed. Although ESD is one of the most effective methods of endoscopy in patients with digestive tract tumors, there are potential complications after surgery, including hemorrhage in the surgical area and stenosis of the esophagus. The objective of this study was to evaluate EMR versus ESD based on post‐operative hemorrhage and esophagus stenosis. All the related articles were retrieved from the e‐databases. The main results were postoperative perforation, hemorrhage, and stenosis after surgery. There were no statistically significant differences in the incidence of post‐operative wound hemorrhage (OR, 1.08; 95% CI, 0.36–3.29 p = 0.89). Similarly, there were no statistically significant differences in the rate of perforation after surgery (OR, 0.57; 95% CI, 0.17–1.95 p = 0.37). There were no statistically significant differences in the incidence of esophageal stricture after surgery (OR, 1.15; 95% CI, 0.26–5.15 p = 0.85). This analysis was different from the earlier meta‐analysis because ESD and EMR did not show any notable differences with respect to the incidence of perforation after surgery, the hemorrhage of the wound or the stenosis of the esophagus. These findings must, however, be supported by more high‐quality studies. [ABSTRACT FROM AUTHOR]

Targeted assembly of nanoparticles in biological systems holds great promise for disease-specific imaging and therapy. However, the current manipulation of nanoparticle dynamics is primarily limited to organic pericyclic reactions, which necessitate the introduction of synthetic functional groups as bioorthogonal handles on the nanoparticles, leading to complex and laborious design processes. Here, we report the synthesis of tyrosine (Tyr)-modified peptides-capped iodine (I) doped CuS nanoparticles (CuS-I@P1 NPs) as self-catalytic building blocks that undergo self-propelled assembly inside tumour cells via Tyr-Tyr condensation reactions catalyzed by the nanoparticles themselves. Upon cellular internalization, the CuS-I@P1 NPs undergo furin-guided condensation reactions, leading to the formation of CuS-I nanoparticle assemblies through dityrosine bond. The tumour-specific furin-instructed intracellular assembly of CuS-I NPs exhibits activatable dual-modal imaging capability and enhanced photothermal effect, enabling highly efficient imaging and therapy of tumours. The robust nanoparticle self-catalysis-regulated in situ assembly, facilitated by natural handles, offers the advantages of convenient fabrication, high reaction specificity, and biocompatibility, representing a generalizable strategy for target-specific activatable biomedical imaging and therapy. In vivo manipulation of the dynamics of nanoparticles' is essential for disease-specific imaging and therapy, but tends to involve complex design processes. Here, the authors report a strategy for manipulating the assembly of nanoparticles in vivo through a self-catalysis-instructed dimerization of tyrosine, offering convenient fabrication, high reaction specificity and biocompatibility. [ABSTRACT FROM AUTHOR]

In this study, the hydrochemical characteristics of groundwater were assessed based on 64 shallow groundwater samples collected in the Guanzhong Basin, China, and the health risk of nitrate (NO3-) in drinking water was assessed. In addition, the spatial distributions of major water quality indicators were investigated, while bivariate plots, saturation index, and stable isotopes were used to reveal the processes controlling groundwater hydrogeochemistry. The results showed that groundwater in the study area was mostly fresh water. However, the maximum and average NO3– concentrations were 397.0 and 92.9 mg/L, respectively, indicating serious groundwater NO3– pollution. The percolation of contaminated river water exhibited considerable impacts on groundwater quality. Carbonate dissolution was the major process controlling the hydrochemical characteristics of groundwater, while human activities were responsible for the high concentrations of groundwater pollutants, especially NO3–. Evaporation fraction of groundwater in the study area revealed by stable hydrogen and oxygen isotopes ranged from 4 to 13% and 4 to 11%, respectively. High non-carcinogenic health risks of NO3– to adults and children were observed in about 46.88 and 75% of the collected groundwater samples, respectively. The risk value ranges were 0-6.00 and 0-14.06, with average values of 1.36 and 3.19, for adults and children, respectively. [ABSTRACT FROM AUTHOR]

While the Healthy China strategy is being implemented, the China Geological Survey has proposed and deployed a health geological survey project, starting a new journey of health geological survey and evaluation to support and serve the construction of Healthy China. However, there are still many urgent problems to be solved in this project, such as the survey vision, the framework of the evaluation indicators, the risk identification method, and the service scopes of the potential achievements. Therefore, in this paper, a framework for health geological survey and evaluation was proposed, which includes regional health geological survey zoning and local ecological risk identification. At regional scale, the framework of indicators, grading standard, score calculation, zoning method of health geological survey, identification of beneficial and harmful health geological factors, and application of achievements were proposed. These contents were presented based on the core evaluation indicators (e.g., the chemical composition, physicochemical properties, topography, and climate of the crustal surface environment caused by geological evolution processes) and the optional evaluation indicators (e.g., sanitary condition, economic level and geo-environment). At local scale, the selection of evaluation area, workflow, risk identification and the application of achievements were proposed to avoid the ecological risks of harmful trace elements and develop beneficial health geological resources. • Proposal of the framework of health geology survey and evaluation. • Presentation of regional health geological survey zoning evaluation indicator and method. • Establishment of the criterion for ecological risk evaluation at a local scale. [ABSTRACT FROM AUTHOR]