Publications by authors named "Mingji Chen"

Aim: The study aimed to investigate the link between dietary copper, iron, zinc, selenium intake with osteopenia and osteoporosis in elderly hypertensive patients.

Methods: The data of hypertensive patients were extracted from the National Health and Nutrition Examination Survey 2005-2010, 2013-2014, and 2017-2018. Data of dietary iron, zinc, copper and selenium intakes were obtained according to 24-h diet recall interviews.

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Low detectability and camouflage skills in the electromagnetic wave and light frequency range provide survival advantages for natural creatures and are essential for understanding the operational principles of the biosphere. Taking inspiration from natural mutualistic symbiosis, this paper proposes a symbiotic electromagnetic shadow camouflage mechanism based on a superdispersive surface, aiming to investigate its impact on the observability of specific objects. The design and experimental results indicate that the symbiotic shadow dihedral can significantly reduce overall scattering quantity, which reaches at least 10 dB shrink in the 12-18 GHz frequency range compared to the contrast object.

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Tunable radar stealth structures are critical components for future military equipment because of their potential to further enhance the design space and performance. Some previous investigations have utilized simple origami structures as the basic adjusting components but failed to achieve the desired broadband microwave absorbing characteristic. Herein, a novel double-broadband switchable microwave absorbing grid structure has been developed with the actuators of inflatable Kresling origami structures.

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Osteosarcoma (OS) is the most common high-grade malignant bone tumor in teenagers. MicroRNAs can function as posttranscriptional regulators of gene expression, playing critical roles in cancer dev-877-3p in OS. Quantitative real-time RT-PCR was carried out for detecting miR-877-3p expression in OS.

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Objective: Our previous study found that resveratrol (Res), which is a phytoalexin, attenuated 6-hydroxydopamine (6-OHDA)-induced motor dysfunction by activating the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway in rats. Therefore, we further explored the protective effect of Res on 6-OHDA-induced damage to PC12 cells with respect to the PI3K/Akt signaling pathway.

Methods: We incubated PC12 cells with 75 μM 6-OHDA for 24 h, and Res was then added at a final concentration of 25 μM; the protective effect was examined via MTT and lactate dehydrogenase (LDH) assays.

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Purpose: This study was to retrospectively evaluate clinical outcomes of geriatric patients with patella fracture treated by percutaneous cerclage wiring and to introduce the surgical technique.

Methods: From January 2009 to December 2015, fifty-seven consecutive geriatric patients of type 34-C patellar fracture underwent closed reduction and percutaneous cerclage wiring fixation in our hospital. Visual Analog Scale (VAS) score, Levack score system, WOMAC test form of pain, stiffness and function, and knee joint range of motion (ROM) were applied for functional evaluation.

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Smart structures with manipulatable properties are highly demanded in many fields. However, there is a critical challenge in the pursuit of transparent windows that allow optical waves (wavelength of µm-nm) for transmitting while blocking microwave (wavelength of cm) in terms of absorbing electromagnetic energy, specifically for meeting the frequency requirement for the 5th generation (5G) mobile networks. For fundamentally establishing novel manipulatable microwave absorbing structures, here, new polymeric aqueous gels as both optically transparent materials and microwave absorbing materials are demonstrated, in which polar networks play significant roles in attenuating electromagnetic energy.

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Acoustic metasurfaces show non-traditional abilities in wave manipulation and provide alternate mechanisms for information communication and invisibility technology. However, most of the mechanisms remain narrow band (relative bandwidth ∼5%), and a wideband trait is essential for engineering applications. For example, controllable effective material properties-reflection or transmission phase-has barely been realized in wideband because the intrinsic dispersion relation is not always editable.

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This study aimed to determine whether resveratrol (Res) delays the progression of 6-hydroxydopamine (6-OHDA)-induced apoptosis via activating the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway. Sprague-Dawley (SD) rats were unilaterally injected with 6-OHDA (8 μg/4 μL) into the substantia nigra of the midbrain. Res (15 and 30 mg/kg) was given orally to the rats for a total of 36 days to examine its protective effects.

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Two-dimensional lattice structures with specific geometric features have been reported to have a negative Poisson's ratio, termed as auxetic metamaterials, that is, stretching-induced expansion in the transversal direction. In this paper, we designed a novel auxetic metamaterial; by utilizing the shape memory effect of the constituent materials, the in-plane moduli and Poisson's ratios can be continuously tailored. During deformation, the curved meshes ensure the rotation of the mesh joints to achieve auxetics.

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Over the past 200 years, Parkinson's disease (PD) has remained an insurmountable challenge. Despite the existence of numerous therapeutic drugs, there are still not enough treatments in the face of the complex pathogenesis of PD. Therefore, the search for more effective therapeutic drugs for PD has extremely important practical significance.

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The implementation of thin structure for broadband microwave absorption is challenging due to the requirement of impedance match across several frequency bands and poor mechanical properties. Herein, we demonstrate a carbon fiber (CF) reinforced flexible thin hierarchical metastructure (HM) composed of lossy materials including carbonyl iron (CI), multiwall carbon nanotube (MWCNT), and silicone rubber (SR) with thickness of 5 mm and optimal concentration selected from 12 formulas. Optimization for the periodical unit size is applied, and impacts of structural sizes on absorption performance are also investigated.

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Smart materials and structures with tunable electromagnetic (EM) properties are highly demanded for active environmental sensitive systems. As polar molecules in the environment, in this work, water and ice are utilized as wetting and freezing conditions to manipulate the electromagnetic response behaviors in a graphene-based composite material, aiming to achieve a smart weather-manipulated EM metamaterial. Owing to the introduced polar water and ice phase in the self-assembled porous electromagnetic attenuating networks, energy consumption of EM waves is significantly altered via multiple scattering of polar induced interfaces.

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An ultrabroadband all-dielectric planar Luneburg lens has been designed and fabricated in this study, which is in the form of a radial gradient lightweight honeycomb column. Because of the novel design of a radial symmetric honeycomb-like microstructure in the subwavelength dimension and the radial gradient configuration according to the refractive index distribution of Luneburg lens, the present lens can focus incident plane waves on the opposite side with high convergence, and its operating frequency range is rather broadband, spanning from 6 to 16 GHz. Besides, the all-dielectric honeycomb-like lens is lightweight with a mass density of 0.

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Microwave absorber with broadband absorption and thin thickness is one of the main research interests in this field. A flexible ultrathin and broadband microwave absorber comprising multiwall carbon nanotubes, spherical carbonyl iron, and silicone rubber is fabricated in a newly proposed pyramidal spatial periodic structure (SPS). The SPS with equivalent thickness of 3.

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Ultralight and highly elastic reduced graphene oxide (RGO)/lignin-derived carbon (LDC) composite aerogels with aligned micron-sized pores and cell walls are prepared using a facile freeze-drying method. The presence of a small fraction of LDC in the cell walls enhances the interfacial polarization effect while almost maintaining the amount of charge carriers and conductivity of the cell walls, greatly boosting the wave absorption capability of the cell walls. RGO/LDC aerogels also show a greater number of large cell walls with better integrity than RGO aerogels, further improving the multiple reflection ability of the aligned cell walls.

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Between May 2015 and May 2017, 496 animals (473 murine rodents and 23 house shrews) were captured in six regions of China. A total of 22.8% (113/496) of throat swabs, 29.

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Ultra-broad-band electromagnetic absorption materials and structures are increasingly attractive for their critical role in competing with the advanced broad-band electromagnetic detection systems. Mechanically soft and weak wax-based materials composites are known to be insufficient to serve in practical electromagnetic absorption applications. To break through such barriers, here we developed an innovative strategy to enable the wax-based composites to be robust and repairable meta-structures by employing a three-dimensional (3D) printed polymeric patterned shell.

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Due to substantial development of electronics and telecommunication techniques, materials with electromagnetic interference (EMI) shielding performance are significant in alleviating the interference impacts induced from a remarkable variety of devices. In the work, we propose novel sandwich structures for manipulating the EM wave transport, which holds unique EMI shielding features of frequency selectivity. By employing electrical and magnetic loss spacers, the resultant sandwich structures are endowed with tunable EMI shielding performance, showing substantial improvements in overall shielding effectiveness along with pronounced shielding peak shift.

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Flexible waterborne polyurethane (WPU)/silver nanowire (AgNW) nanocomposites with unidirectionally aligned micrometer-sized pores are fabricated using a facile freeze-drying process, and their dimensions, densities, and AgNW contents are easily controllable. The high-aspect-ratio AgNWs are well-dispersed in the nanocomposite cell walls, giving the nanocomposites good compression strength and excellent electrical conductivity even at very low densities. The large conductivity mismatch between the AgNWs and WPU also induces substantial interfacial polarization that benefits the absorption of electromagnetic (EM) waves, whereas the aligned cell walls promote multireflections of the waves in the porous architectures, further facilitating the absorption.

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Multiwalled carbon nanotube/polymer composites with aligned and isotropic micropores are constructed by a facile ice-templated freeze-drying method in a wide density range, with controllable types and contents of the nanoscale building blocks, in order to tune the shielding performance together with the considerable mechanical and electrical properties. Under the mutual promotion of the frame and porous structure, the lightweight high-performance shielding is achieved: a 2.3 mm thick sample can reach 46.

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Mass production of surface mount devices (SMDs) relies heavily on reflow soldering and has become the cornerstone of today's electronic industry. However, the traditional reflow soldering technique is characterized by high heating temperatures, toxic solder materials and low recycling rate of SMDs. Here, we propose a new patterned structure of Au nanowire arrays named a surface fastener through which cold bonding for surface mount technology can be realized.

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