Search Results (6)

Electro-conductive films with excellent flexibility and thermal behavior have great potential in the fields of wearable electronics, artificial muscle, and soft robotics. Herein, we report a super-elastic and electro-conductive composite film with a sandwich structure. The composite film was constructed by spraying Polyvinyl alcohol (PVA) polymers onto a buckled conductive carbon nanotube-polydimethylsiloxane (CNTs-PDMS) composite film. In this system, the PVA and PDMS provide water sensing and stretchability, while the coiled CNT film offers sufficient conductivity. Notably, the composite film possesses high stretchability (205%), exceptional compression sensing ability, humility sensing ability, and remarkable electrical stability under various deformations. The produced CNT composite film exhibited deformation (bending/twisting) and high electro-heating performance (108 °C) at a low driving voltage of 2 V. The developed CNT composite film, together with its exceptional sensing and electrothermal performance, provides the material with promising prospects for practical applications in wearable electronics. Full article

Terahertz (THz) non-destructive testing can detect internal defects in dielectric materials. However, this technology is mainly used for detecting thin and simple structures at present, lacking validations for the detection effectiveness of internal defects in thicker and more complex structures, such as fiber-web-reinforced composite sandwich panels. In this study, samples of fiber-web-reinforced polymethacrylimide foam sandwich panels, which are, respectively, 20 mm and 30 mm thick, were made to detect the internal debonding, inclusion, pore, and crack defects by the THz time-domain spectroscopy system (THz-TDS). The peak-to-peak-imaging algorithm, maximum-amplitude-imaging algorithm, minimum-amplitude-imaging algorithm, pulse-width-imaging algorithm, and time-of-flight-imaging algorithm were used to process and image the collected THz signals. The results showed that the peak-to-peak-imaging algorithm had the best performance. To address the low imaging resolution of THz-TDS, a block-based super-resolution reconstruction method—SSSRGAN—is proposed, which can improve image resolution while maintaining the clear edge contours of defects. The defect-detection results of the samples showed that THz-TDS could detect all pore, debonding, and crack defects, with a minimum size of 3 mm for pores and debonding and a minimum thickness of 1 mm for cracks. The method showed poor detection performance for inclusions with a thickness of 0.053 mm, but could still extract the defect features. Based on the THz-TDS reflection mode measurement principle, the thickness information of the panel, foam core, and web of the samples was calculated: the measurement error was no more than 0.870 mm for Sample #1 and no more than 0.270 mm for Sample #2, demonstrating the accuracy of THz-TDS in measuring the dimensions of sandwich panel structures. In general, THz technology shows potential for detecting internal defects and performing dimensional measurements in complex structures. With the advancement of portable devices and enhancements in detection speed, real-time on-site detection is anticipated in the future. Full article

Tumor cell-derived extracellular vesicles and their cargo of bioactive substances have gradually been recognized as novel biomarkers for cancer diagnosis. Meanwhile, the PD-L1 (Programmed Death-Ligand 1) protein, as an immune checkpoint molecule, is highly expressed on certain tumor cells and holds significant potential in immune therapy. In comparison to PD-L1 monoclonal antibodies, the inhibitory effect of PD-L1 siRNA (small interfering RNA) is more advantageous. In this article, we introduced a microfluidic chip integrating cell cultivation and exosome detection modules, which were intended for the investigation of the gene silencing effect of PD-L1 siRNA. Basically, cells were first cultured with PD-L1 siRNA in the chip. Then, the secreted exosomes were detected via super-resolution imaging, to validate the inhibitory effect of siRNA on PD-L1 expression. To be specific, a “sandwich” immunological structure was employed to detect exosomes secreted from HeLa cells. Immunofluorescence staining and DNA-PAINT (DNA Point Accumulation for Imaging in Nanoscale Topography) techniques were utilized to quantitatively analyze the PD-L1 proteins on HeLa exosomes, which enabled precise structural and content analysis of the exosomes. Compared with other existing PD-L1 detection methods, the advantages of our work include, first, the integration of microfluidic chips greatly simplifying the cell culture, gene silencing, and PD-L1 detection procedures. Second, the utilization of DNA-PAINT can provide an ultra-high spatial resolution, which is beneficial for exosomes due to their small sizes. Third, qPAINT could allow quantitative detection of PD-L1 with better precision. Hence, the combination of the microfluidic chip with DNA-PAINT could provide a more powerful integrated platform for the study of PD-L1-related tumor immunotherapy. Full article

High-pressure air compressor is one of the most important pieces of equipment for ships, which is one of the main sources of vibration on board. There are a lot of welded plate structures in the installation base of the compressor, which have weak stiffness and low damping and are prone to vibration radiation due to excitation. In this paper, a section of the base is taken as the test object. Through the analysis of the working principle, the vibration characteristics of the air compressor and the corresponding transmission path are mastered. In addition, it is tested and screened by filling different kinds of damping materials. Finally, it is concluded that the super-damping rubber has a better damping effect on the specimen of the base. According to the vibration characteristics of the plate structure, the sandwich structure, which is fixed by a restraint layer with super-damping rubber, is bonded to the plate. When the base is excited, the restraint layer moves in relative slippage, and the damping rubber can consume part of the vibration energy so that the vibration of the plate structure is reduced. Moreover, the technology has the characteristics of small additional mass and a good damping effect. It has been proved that the feet acceleration is reduced by 6 dB or above through experiments. Full article

High-risk human papillomavirus (HPV) infection is an important cause of cervical cancer formation; therefore, being able to detect high-risk HPV (e.g., HPV-16) is important for the early treatment and prevention of cervical cancer. In this study, a combination of a 3-aminopropyltriethoxysilane (APTES) modified gold electrode and a super sandwich structure was creatively developed, resulting in the development of a biosensor that is both sensitive and stable for the detection of HPV-16. The electrochemical biosensor possesses a lower detection limit compared with previous studies with an LOD of 5.475 × 10⁻¹⁶ mol/L and it possesses a wide linear range from 1.0 × 10⁻¹³ mol/L to 1.0 × 10⁻⁶ mol/L (R² = 0.9923) for the target DNA. The experimental data show that the sensor has good stability, and there is no significant decrease in the current response value after 7 days in the low-temperature environment. In addition, the sensor proved to be a powerful clinical tool for disease diagnosis because it showed good interference resistance in complex human serum samples. Full article

Sodium, potassium, and calcium compounds of trimethyl((2,3,4,5-tetramethylcyclopentadien-1-yl)ethynyl)silane (CpMe₄(C≡CSiMe₃)) were synthesized and characterized by X-ray diffraction and standard analytical methods. The sodium derivative was obtained by deprotonation of CpMe₄(C≡CSiMe₃)H with Na{N(SiMe₃)₂} to give a monomeric complex [NaCpMe₄(C≡CSiMe₃)(THF)₃]. In a similar reaction, starting from K{N(SiMe₃)₂} the corresponding potassium compound [KCpMe₄(C≡CSiMe₃)(THF)₂]_n, which forms a polymeric super sandwich structure in the solid state, was obtained. Subsequently, salt metathesis reactions were conducted in order to investigate the versatility of the CpMe₄(C≡CSiMe₃)⁻ ligand in alkaline earth chemistry. The reaction of [KCpMe₄(C≡CSiMe₃)(THF)₂]_n with CaI₂ afforded the dimeric complex [CaCpMe₄(C≡CSiMe₃)I(THF)₂]₂, in which both CpMe₄(C≡CSiMe₃)Ca units are bridged by iodide in a μ² fashion. In-depth NMR investigation indicates that [CaCpMe₄(C≡CSiMe₃)I(THF)₂]₂ is in a Schlenk equilibrium with [{CpMe₄(C≡CSiMe₃)}₂Ca(THF)_x] and CaI₂(THF)₂, as is already known for [CaCp*I(THF)₂]. Full article