This study develops a macroscopic model of mass transport in electroporated biological tissue in order to predict the cellular drug uptake. The change in the macroscopic mass transport coefficient is related to the increase in electrical conductivity resulting from the applied electric field. Additionally, the model considers the influences of both irreversible electroporation (IRE) and the transient resealing of the cell membrane associated with reversible electroporation. Two case studies are conducted to illustrate the applicability of this model by comparing transport associated with two electrode arrangements: side-by-side arrangement and the clamp arrangement. The results show increased drug transmission to viable cells is possible using the clamp arrangement due to the more uniform electric field.
Irradiation with UV-C band ultraviolet light is one of the most commonly used ways of disinfecting water contaminated by pathogens such as bacteria and viruses. Sonoluminescence, the emission of light from acoustically-induced collapse of air bubbles in water, is an efficient means of generating UV-C light. However, because a spherical bubble collapsing in the bulk of water creates isotropic radiation, the generated UV-C light fluence is insufficient for disinfection. Here, we show that we can create a UV light beam from aspherical air bubble collapse near a gallium-based liquid-metal microparticle. The beam is perpendicular to the metal surface and is caused by the interaction of sonoluminescence light with UV plasmon modes of the metal. We calculate that such beams can generate fluences exceeding 10 mJ/cm 2 , which is sufficient to irreversibly inactivate most common pathogens in water with the turbidity of more than 5 Nephelometric Turbidity Units.Introduction.-The ability of UV-C light (200 − 280 nm) to inactivate bacteria, viruses and protozoa is widely used as an environmentally-friendly, chemical-free and highly effective means of disinfecting and safeguarding water against pathogens responsible for cholera, polio, typhoid, hepatitis and other bacterial, viral and parasitic diseases 1 . UV-C light inactivates pathogens through absorption of radiation energy by their cellular RNA and DNA prompting the formation of new bonds between adjacent nucleotides. This results in a photochemical damage that renders pathogens incapable of reproducing and infecting 1 .However, some pathogens can recover from photochemical damage when the initial UV dosage (fluence) is not sufficiently high 1 . Thus, the fluence must exceed 5 and 10 mJ/cm 2 , respectively, to inactivate 99% and 99.9% of Giardia and Cryptosporidium pathogens 2 . These specifications are for water purified from solid particles larger than 5 − 10 µm [turbidity less than 5 Nephelometric Turbidity Units (NTU)] 2 . Otherwise, particles can shield pathogens from the UV light, thereby allowing many pathogens to recover and infect.The filtration of natural water presents significant challenges for remote communities and developing nations 2 . Moreover, filtered water, dissolved iron, organic salts and the pathogen population itself absorb UV-C light. Therefore, a 50% UV radiation loss has been accepted as suitable for practical use 1 .To enable UV disinfection of turbid water, we use the effect of sonoluminescence-the emission of broadband UV light in acoustically-induced collapse of air bubbles in water 3,4 . Air bubbles suitable for sonoluminescence can be created in natural water 5 and we show that they can act as compact sources of germicidal radiation lo-
This paper describes the first high-order accurate, fully compressible, multiphase model to simulate the expansion and collapse of a near-wall cavitation bubble in a low-frequency ultrasound field. The model captures the compressibility of the fluids, subsequent shocks, and a physically correct representation of the acoustic input through an immersed moving boundary that represents the active face of the ultrasound transducer face. The model’s predictions of bubble dynamics are compared to existing models that are able to capture the collapse of a near wall bubble, (1) the Rayleigh growth and collapse model and (2) the Rayleigh-Plesset growth initialized collapse model, highlighting the limitations of the previously developed models.
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