Evaluation of antimicrobial effects of photo-sonodynamic antimicrobial chemotherapy based on nano-micelle curcumin on virulence gene expression patterns in Acinetobacter baumannii

Background: Abaumannii baumannii rapidly resistance to a wide range of antimicrobial agents. The combination of antimicrobial photodynamic therapy (aPDT) and sonodynamic antimicrobial chemotherapy (SACT) known as photo-sonodynamic antimicrobial chemotherapy (PSACT) has received considerable attention as one of the emerging and promising strategies against microbial infections. Objective: This study aimed to investigate the antimicrobial effects of PSACT based on nano-micelle curcumin (N-MCur) on the virulence gene expression patterns in A. baumannii. Materials and methods: N-MCur as a photo-sonosensitizer was synthesized and confirmed. To determine sub-significant reduction dose of PSACT, sub-significant reduction dose of N-MCur and blue laser light during aPDT, and ultrasound power output during SACT were assessed. Finally, changes in the expression of genes involved in treated A. baumannii by minimum sub-significant reduction dose of PSACT were determined using quantitative real-time-PCR (qRT-PCR). Results: PSACT using 12.5 mM N-MCur at the ultrasound power outputs of 28.7, 36.9, and 45.2 mW/cm2 with 4 min irradiation time of blue laser, as well as, 6.2 mM N-MCur at an ultrasound power output of 45.2 mW/cm2 plus 3 min blue laser irradiation time exhibited the significant dose-dependent reduction against A. baumannii cell viability compared to the control group (P<0.05). After treatment of A. baumannii using 3.1 mM N-MCur + 2 min blue laser irradiation time + 28.7 mW/cm2 ultrasound as the minimum sub-significant reduction doses of PSACT, mRNA expression was significantly upregulated to 6.0-, 11.2-, and 13.7-folds in recA, blsA, and dnaK and downregulated to 8.6-, 10.1-, and 14.5-folds in csuE, espA, and abaI, respectively. Conclusions: N-MCur-mediated PSACT could regulate the expression of genes involved in A. baumannii pathogenesis. Therefore, PSACT can be proposed as a promising application to treat infections caused by A. baumannii.

Dependence of the energy efficiency of the acousto-optic modulator of terahertz radiation on the dimensions of the ultrasound transducer

The paper presents results of experimental investigation of an acousto-optic modulator of terahertz radiation based on liquefied sulfur hexafluoride. It was found that the intensity of diffracted radiation at a fixed ultrasound power depends on the dimensions of the ultrasound transducer. The optimal size of the ultrasound transducer in the direction orthogonal to the plane of the acousto-optic interaction was determined, at which the maximum energy efficiency of the acousto-optic modulator was achieved.

Critical Variables Influencing the Ultrasound-Assisted Extraction of Bioactive Compounds—A Review

Ultrasound-assisted extraction (UAE) is a novel methodology, belonging to the so-called “Green Chemistry”, which has gained interest in recent years due to the potential to recover bioactive compounds, especially those from plant matrices. It is widely recognized that the extraction of molecules by UAE gives rise to higher or similar yields than those obtained by traditional extraction methods. UAE has certain advantages inherent to Green Chemistry extraction methods, such as short extraction time and low solvent consumption. The aim of this review is to critically present the different variables and parameters that can be modified in UAE, such as ultrasound power, time, temperature, solvent, and solid to solvent ratio that influence yield and extraction performance.

Mathematical Modelling of Ultrasound-Assisted Extraction Kinetics of Bioactive Compounds from Artichoke By-Products

Valorization of an artichoke by-product, rich in bioactive compounds, by ultrasound-assisted extraction, is proposed. The extraction yield curves of total phenolic content (TPC) and chlorogenic acid content (CAC) in 20% ethanol (v/v) with agitation (100 rpm) and ultrasound (200 and 335 W/L) were determined at 25, 40, and 60 °C. A mathematical model considering simultaneous diffusion and convection is proposed to simulate the extraction curves and to quantify both temperature and ultrasound power density effects in terms of the model parameters variation. The effective diffusion coefficient exhibited temperature dependence (72% increase for TPC from 25 °C to 60 °C), whereas the external mass transfer coefficient and the equilibrium extraction yield depended on both temperature (72% and 90% increases for TPC from 25 to 60 °C) and ultrasound power density (26 and 51% increases for TPC from 0 (agitation) to 335 W/L). The model allowed the accurate curves simulation, the average mean relative error being 5.3 ± 2.6%. Thus, the need of considering two resistances in series to satisfactorily simulate the extraction yield curves could be related to the diffusion of the bioactive compound from inside the vegetable cells toward the intercellular volume and from there, to the liquid phase.

Process Optimization for Ultrasound-Assisted Starch Production from Cassava (Manihot esculenta Crantz) Using Response Surface Methodology

Ultrasound-assisted extraction (UAE) has been optimized to improve the current cassava starch production by conventional maceration for the extraction method. Evaluation of several extraction parameters disclosed significant effects (p < 0.05) by three studied factors (ultrasound power, x1; pulse duty-cycle, x2; and solvent to sample ratio, x3). Subsequently, a Box-Behnken design (BBD) in conjunction with response surface methodology (RSM) was employed to optimise the three factors at three levels: x1 (30, 60, 90%), x2 (0.3, 0.6, 0.9 s−1), and x3 (10:1, 20:1, 30:1). The model built for the RSM was validated through the coefficient of determination (R2 > 0.95), prediction error (2.12%), and lack-of-fit (0.71) values. The model validation suggested that the RSM was adequate for the observed data at the 95.0% confidence level. The optimum yield of cassava starch extraction was achieved by applying 90% for ultrasound power, pulse duty-cycle of 1.0 s−1, and solvent to sample ratio of 30:1 with 10 min extraction time. Finally, the UAE produced starch with a purity of 88.36% and a lower viscosity than the commercial sample due to the granules’ size alteration. Hence, apart from speeding up the extraction process, UAE was worthwhile for the starch modification that could maintain the viscosity at a lower value (1920 cP) than the commercial starch (1996 cP) at the highest studied temperature treatment of 70 °C.