Mono- and Dicationic DABCO/Quinuclidine Composed Nanomaterials for the Loading of Steroidal Drug: 32 Factorial Design and Physicochemical Characterization

Oil-in-water nanoemulsions (NEs) are considered a suitable nanotechnological approach to improve the eye-related bioavailability of lipophilic drugs. The potential of cationic NEs is prominent due to the electrostatic interaction that occurs between the positively charged droplets with the negatively charged mucins present in the tear film. This interaction offers prolonged NEs residence at the ocular surface, increasing the drug absorption. Triamcinolone acetonide (TA) is one of the first pharmacologic strategies applied as an intravitreal injection in the treatment of age-related macular degeneration (AMD). Newly synthesized quaternary derivatives of 1,4-diazabicyclo[2.2.2]octane (DABCO) and quinuclidine surfactants have been screened with the purpose to select the best compound to formulate long-term stable NEs that combine the best physicochemical properties for the loading of TA intended for ocular administration.

Fabricating an Electrospray Ionization Chip Based on Induced Polarization and Liquid Splitting

The coupling of the microfluidic chip to mass spectrometry (MS) has attracted considerable attention in the area of chemical and biological analysis. The most commonly used ionization technique in the chip–MS system is electrospray ionization (ESI). Traditional chip-based ESI devices mainly employ direct electrical contact between the electrode and the spray solvent. In this study, a microchip ESI source based on a novel polarization-splitting approach was developed. Specifically, the droplet in the microchannel is first polarized by the electric field and then split into two sub-droplets. In this process, the charge generated by polarization is retained in the liquid, resulting in the generation of two charged droplets with opposite polarities. Finally, when these charged droplets reach the emitter, the electrospray process is initiated and both positive and negative ions are formed from the same solution. Preliminary experimental results indicate that the coupling of this polarization-splitting ESI (PS-ESI) chip with a mass spectrometer enables conventional ESI-MS analysis of various analytes.

Observation of charged droplets from electrospray ionization (ESI) plumes in API mass spectrometers

Electrospray ionization (ESI) generates bare analyte ions from charged droplets, which result from spraying a liquid in a strong electric field. Experimental observations available in the literature suggest that at least a significant fraction of the initially generated droplets remain large, have long lifetimes, and can thus aspirate into the inlet system of an atmospheric pressure ionization mass spectrometer (API-MS). We report on the observation of fragment signatures from charged droplets penetrating deeply the vacuum stages of three commercial mass spectrometer systems with largely different ion source and spray configurations. Charged droplets can pass through the ion source and pressure reduction stages and even into the mass analyzer region. Since droplet signatures were found in all investigated instruments, the incorporation of charged droplets is considered a general phenomenon occurring with common spray conditions in ESI sources.

Development and Prospect of UAV-Based Aerial Electrostatic Spray Technology in China

Aerial electrostatic spray technology for agriculture is the integration of precision agricultural aviation and electrostatic spray technology. It is one of the research topics that have been paid close attention to by scholars in the field of agricultural aviation. This study summarizes the development of airborne electrostatic spray technology for agricultural use in China, including the early research and exploration of Chinese institutions and researchers in the aspects of nozzle structure design optimization and theoretical simulation. The research progress of UAV-based aerial electrostatic spray technology for agricultural use in China was expounded from the aspects of nozzle modification, technical feasibility study, influencing mechanism of various factors, and field efficiency tests. According to the current development of agricultural UAVs and the characteristics of the farmland environment in China, the UAV-based aerial electrostatic spray technology, which carries the airborne electrostatic spray system on the plant protection UAVs, has a wide potential in the future. At present, the application of UAV-based aerial electrostatic spray technology has yet to be further improved due to several factors, such as the optimization of the test technology for charged droplets, the impact of UAV rotor wind field, comparison study on charging modes, and the lack of technical accumulation in the research of aerial electrostatic spray technology. With the continuous improvement of the research system of agricultural aviation electrostatic spray technology, UAV-based electrostatic spray technology will give play to the advantages in increasing the droplets deposition on the target and reducing environmental pollution from the application of pesticides. This study is capable of providing a reference for the development of the UAV-based agricultural electrostatic spray technology and the spray equipment.

Electrochemical and Chemical Mechanisms of the Erosion-Corrosion Process of Wet-Steam Turbine Rotor Blades Destruction Under the Influence of Electrified Moisture

This paper is devoted to the electrochemical and chemical aspects of the erosion-corrosion destruction of the surface layer of a wet-steam turbine rotor blade under the influence of an electrified working fluid. It considers a hypothesis about a complex mechanochemical-electrochemical mechanism of chromium and iron wash-out from the surface layer of the rotor blade metal during the destruction of the oxide film under the influence of a high-speed wet steam flow. Various versions of this process are analyzed for positive, negative, quasi-neutral, and neutral electrifications of wet steam. The possibility to hydrogenate the surfaces of rotor blades under the influence of negatively-charged droplets is shown theoretically. The damage to the blades in this case is similar to that from anodic etching. It is also shown that the process of blade surface hydrogenation takes place in any case both for electrically-charged droplets and for neutral ones. However, in the case of neutral droplets, the intensity of the process is insignificant. An experimental study was carried out for the erosion-damaged surface of a last-stage rotor blade from of the BK-50 LMP turbine that had exhausted its lifetime. The quantitative content of chromium was determined in the steel sample cut out from the blade. A decrease in chromium content in the erosion-damaged blade surface layer was found. To test the hypothesis about the similarity between the process of anodic electro-etching and the process of surface destruction under the influence of negatively-charged droplets, an electrochemical experiment was carried out on a model sample of 20X13 chromium steel. The reliefs of the damaged areas on the model sample after anodic etching and on the observable blade in the zone of exposure to negatively-charged droplets are shown to be similar. The experimental studies have confirmed the presence of a complex mechanochemical-electrochemical process of blade destruction. On the basis of the data obtained, recommendations for extending the useful life of turbine blades are formulated.