Exploration on Structural and Optical Properties of Nanocrystalline Cellulose/Poly(3,4-Ethylenedioxythiophene) Thin Film for Potential Plasmonic Sensing Application

There are extensive studies on the development of composite solutions involving various types of materials. Therefore, this works aims to incorporate two polymers of nanocrystalline cellulose (NCC) and poly(3,4-ethylenethiophene) (PEDOT) to develop a composite thin film via the spin-coating method. Then, Fourier transform infrared (FTIR) spectroscopy is employed to confirm the functional groups of the NCC/PEDOT thin film. The atomic force microscopy (AFM) results revealed a relatively homogeneous surface with the roughness of the NCC/PEDOT thin film being slightly higher compared with individual thin films. Meanwhile, the ultraviolet/visible (UV/vis) spectrometer evaluated the optical properties of synthesized thin films, where the absorbance peaks can be observed around a wavelength of 220 to 700 nm. An optical band gap of 4.082 eV was obtained for the composite thin film, which is slightly lower as compared with a single material thin film. The NCC/PEDOT thin film was also incorporated into a plasmonic sensor based on the surface plasmon resonance principle to evaluate the potential for sensing mercury ions in an aqueous medium. Resultantly, the NCC/PEDOT thin film shows a positive response in detecting the various concentrations of mercury ions. In conclusion, this work has successfully developed a new sensing layer in fabricating an effective and potential heavy metal ions sensor.

Protocol for subcellular targeted microthermal protein damage in cells cultivated on plasmonic nanosilver-modified surfaces

Despite proteotoxic stress and heat shock are implicated in diverse pathologies, currently no methodology to inflict defined, subcellular thermal damage exists. Here, we present a protocol for such a single-cell method compatible with laser-scanning microscopes, adopting the plasmon resonance principle. The method is based on modified microscopic cell culture plates, pre-coated by a layer of anisotropic silver NPs allowing excitation through targeted irradiation by conventional lasers used in the laser scanning microscopes and allowing controllable heating. Dose-defined heat causes protein damage in subcellular compartments, rapid heat-shock chaperones recruitment and stress signalling, thereby allowing unprecedented spatiotemporal analysis of thermal damage with broad applicability in biomedicine.

Microthermal-induced subcellular-targeted protein damage in cells on plasmonic nanosilver-modified surfaces evokes a two-phase HSP-p97/VCP response

Despite proteotoxic stress and heat shock being implicated in diverse pathologies, currently no methodology to inflict defined, subcellular thermal damage exists. Here, we present such a single-cell method compatible with laser-scanning microscopes, adopting the plasmon resonance principle. Dose-defined heat causes protein damage in subcellular compartments, rapid heat-shock chaperone recruitment, and ensuing engagement of the ubiquitin–proteasome system, providing unprecedented insights into the spatiotemporal response to thermal damage relevant for degenerative diseases, with broad applicability in biomedicine. Using this versatile method, we discover that HSP70 chaperone and its interactors are recruited to sites of thermally damaged proteins within seconds, and we report here mechanistically important determinants of such HSP70 recruitment. Finally, we demonstrate a so-far unsuspected involvement of p97(VCP) translocase in the processing of heat-damaged proteins. Overall, we report an approach to inflict targeted thermal protein damage and its application to elucidate cellular stress-response pathways that are emerging as promising therapeutic targets.

Observations of a mix of cold and warm electrons by RPC-MIP at 67P/Churyumov-Gerasimenko

Context. The Mutual Impedance Probe (MIP) of the Rosetta Plasma Consortium (RPC) onboard the Rosetta orbiter which was in operation for more than two years, between August 2014 and September 2016 to monitor the electron density in the cometary ionosphere of 67P/Churyumov-Gerasimenko. Based on the resonance principle of the plasma eigenmodes, recent models of the mutual impedance experiment have shown that in a two-electron temperature plasma, such an instrument is able to separate the two isotropic electron populations and retrieve their properties. Aims. The goal of this paper is to identify and characterize regions of the cometary ionized environment filled with a mix of cold and warm electron populations, which was observed by Rosetta during the cometary operation phase. Methods. To reach this goal, this study identifies and investigates the in situ mutual impedance spectra dataset of the RPC-MIP instrument that contains the characteristics of a mix of cold and warm electrons, with a special focus on instrumental signatures typical of large cold-to-total electron density ratio (from 60 to 90%), that is, regions strongly dominated by the cold electron component. Results. We show from the observational signatures that the mix of cold and warm cometary electrons strongly depends on the cometary latitude. Indeed, in the southern hemisphere of 67P, where the neutral outgassing activity was higher than in northern hemisphere during post-perihelion, the cold electrons were more abundant, confirming the role of electron-neutral collisions in the cooling of cometary electrons. We also show that the cold electrons are mainly observed outside the nominal electron-neutral collision-dominated region (exobase), where electrons are expected to have cooled down. This which indicates that the cold electrons have been transported outward. Finally, RPC-MIP detected cold electrons far from the perihelion, where the neutral outgassing activity is lower, in regions where no electron exobase was expected to have formed. This suggests that the cometary neutrals provide a more frequent or efficient cooling of the electrons than expected for a radially expanding ionosphere.

Influence Study of Gas Pressure on the Volume Measurement of Engine Combustion Chamber by Using Helmholtz Resonance

The combustion chamber of automobile engine is a place where gasoline is burned to provide power for automobile driving and its size has a great influence on engine performance. However, because of the irregularity of the combustion chamber, it is difficult to measure it accurately and efficiently. The principle of Helmholtz resonance reveals the functional relationship between the volume and the resonant frequency of the closed cavity. Having used the Helmholtz resonance principle, the equipment for measuring the combustion chamber of automobile engine accurately and efficiently has been built. The conditions under which the cavity is stimulated to produce resonance are explored, the relationship between volume and the pressure is deduced. Experiments are designed to verify the correctness and accuracy of the measurement. The measuring instrument is improved and the accuracy of the volume measurement is increased. The application of the high precision and high efficiency of non-contact acoustic principle in cavity volume dynamic measurement has been realized.

A Piezoelectric Resonance Pump Based on a Flexible Support

Small volume changes are important factors that restrict the improvement of the performance of a piezoelectric diaphragm pump. In order to increase the volume change of the pump chamber, a square piezoelectric vibrator with a flexible support is proposed in this paper and used as the driving unit of the pump. The pump chamber diaphragm was separated from the driving unit, and the resonance principle was used to amplify the amplitude of the pump diaphragm. After analyzing the working principle of the piezoelectric resonance pump and establishing the motion differential equation of the vibration system, prototypes with different structural parameters were made and tested. The results show that the piezoelectric resonance pump resonated at 236 Hz when pumping air. When the peak-to-peak voltage of the driving power was 220 V, the amplitude of the diaphragm reached a maximum value of 0.43933 mm, and the volume change of the pump was correspondingly improved. When the pump chamber height was 0.25 mm, the output flow rate of pumping water reached a maximum value of 213.5 mL/min. When the chamber height was 0.15 mm, the output pressure reached a maximum value of 85.2 kPa.