In this paper, we propose a highly selective and efficient gas detection system based on a narrow-band IR metasurface emitter integrated with a resistive heater. In order to develop the sensor for the detection of specific gases, both the microheater and metasurface structures have been optimized in terms of geometry and materials. Devices with different metamaterial structures and geometries for the heater have been tested. Our prototype showed that the modification of the spectral response of metasurface-based structures is easily achieved by adapting the geometrical parameters of the plasmonic micro-/nanostructures in the metasurface. The advantage of this system is the on-chip integration of a thermal source with broad IR radiation with the metasurface structure, obtaining a compact selective radiation source. From the experimental data, narrow emission peaks (FWHM as low as 0.15 μm), corresponding to the CO2, CH4, and CO absorption bands, with a radiant power of a few mW were obtained. It has been shown that, by changing the bias voltage, a shift of a few tens of nm around the central emission wavelength can be obtained, allowing fine optimization for gas detection applications.
1 January 2021 in IOP Conference Series: Materials Science and Engineering
This paper presents the preparation and characterization of MWCNT - Multi-Walled Carbon Nano-Tube/epoxy nanocomposites, as materials with a good yield for shielding electromagnetic interferences - EMI. Both the precursors used, and the nanocomposites obtained were characterized by different techniques: FTIR - Fourier transform infrared spectroscopy, Raman spectroscopy, SEM - Scanning Electron Microscope and XRD - X-ray diffraction. The electrical and mechanical properties of the nanocomposites were estimated compared to the epoxy resin without addition. Electromagnetic interference shielding tests were conducted in the 2.5 - 6.4 GHz frequency band. The results were found to be promising since for the MWCNT/epoxy sample it was obtained a 20 dB attenuation when compared with the ambient air.
Knee osteoarthritis is treated based on total knee arthroplasty (TKA) interventions. The most frequent failure cause identified in surgical practice is due to wear and oxidation processes of the prothesis’ tibial insert. This component is usually manufactured from ultra-high molecular weight polyethylene (UHMWPE). To estimate the clinical complications related to a specific prosthesis design, we investigated four UHMWPE tibial inserts retrieved from patients from Clinical Hospital Colentina, Bucharest, Romania. For the initial analysis of the polyethylene degradation modes, macrophotography was chosen. A light stereomicroscope was used to estimate the structural performance and the implant surface degradation. Scanning electron microscopy confirmed the optical results and fulfilled the computation of the Hood index. The oxidation process in UHMWPE was analyzed based on Fourier-transform infrared spectroscopy (FTIR). The crystallinity degree and the oxidation index were computed in good agreement with the existing standards. Mechanical characterization was conducted based on the small punch test. The elastic modulus, initial peak load, ultimate load, and ultimate displacement were estimated. Based on the aforementioned experimental tests, a variation between 9 and 32 was found in the case of the Hood score. The oxidation index has a value of 1.33 for the reference sample and a maximum of 9.78 for a retrieved sample.
Cancer is considered today as a prevalent research direction due to the fact that, by 2050, more than 30 million cases will occur, followed by about 19 million deaths. It is expected that scholars will search for new, innovative, and localized therapies to ensure a much more targeted treatment with reduced side effects. Magnetic hydrogels overcome the disadvantages of classical magnetic nanoparticles in various oncological domains, including magnetic hyperthermia, theragnostic, immunotherapy, and, notably, regenerative medicine and contrast substances. We will review the magnetic hydrogel topics that may be involved as a potential application for cancer. Firstly, we present the international context and subject importance in the framework of statistics estimated by some researchers. Then, the magnetic hydrogel synthesis method will be briefly described with examples extracted from the literature. Supplementary, we will emphasize the main attributes of an ideal magnetic hydrogel, and last but not least, we will review some of the latest in vitro and in vivo studies in a direct relationship with magnetic hyperthermia, chemotherapeutic drug release dynamics, and immunotherapy used as single strategies or in combination, by underling the magnetic properties of the hydrogels and importance of application of magnetic fields. We will conclude our review paper by discussing toxicity issues, future trends, limitations, and proposed new approaches to address them.
Background: Biodegradable implants manufactured from Mg-based alloys are one of the most commonly used in orthopedics. However, their overall clinical acceptance is influenced by their fast corrosion speed and hydrogen emission. Based on an innovative manufacturing route previously described, this study introduces a preliminary proof-of-concept for a Gemini-assisted Digital Twin (Gemini-DT),which is an AI-augmented in silico framework designed to consider a MgF2 conversion coating on the implant surface and to model the synchronization of the degradation process with new bone formation. Methods: Based on the integration of experimental data for Mg-Nd and Mg-Zn alloys and by considering the implant geometry and coating formation, we developed, in collaborative work with LLM Gemini 1.5 Flash (Google), a four-module cognitive framework (surface thermodynamic synergy (Module 1), degradation analysis and alloy extract concentration management (Module 2), micro-channel fluidics and mechanical stability (Module 3), and bio-mechanical synchronization and regenerative evaluation (Module 4)) to evaluate simulated implant behaviors). Results: Using a 10,000 iteration Monte Carlo stability simulation, the model demonstrated a potential 12% reduction in false-negative design screening errors compared to rigid rule-based systems, achieving strong internal decision consistency in sustaining the mandated parametric compliance window. Computational verification supports the projected biocompatibility trends of Mg-Zn alloys, as previously demonstrated in our in vivo studies. Conclusions: Our research leads to a consistent computational architecture dedicated to Mg-based implants and offers a robust platform for virtual design and optimization. These observations suggest that the developed model can recover viable designs, whereas traditional linear models may reject them.