ABSTRACT
Spearmint essential oil (SEO), one of the economically valuable natural products, has special importance in the food, pharmaceutical, and perfumery industries due to its antifungal, antioxidant, and enzyme inhibitory properties. In this study, we optimized and evaluated the effect of three pre-treatments on the extraction of SEO for quantity and quality: ultrasonic bath (UB), water to material ratio-ultrasonic bath (W/M-UB), and cold plasma-ultrasonic bath (CP-UB). Three experiments were designed using the central composite design (CCD) of response surface methodology (RSM). Experimental treatments included UB temperature (30-80°C) and time duration (1-30 min), cold plasma (CP) power (15-24 kV), and water/material ratio (10-40). Then, SEOs were extracted by hydro-distillation using the Clevenger apparatus. The results showed that SEO yield in the optimal conditions of treatments was 119.7%, 206.6%, and 155.7% higher in UB, W/M-UB, and CP-UB pretreatments respectively, in comparison to control sample and optimized conditions were UB temperature: 37.3°C and UB time: 5.2 min at UB treatment, 33.9 of W/M ratio, 69.9°C of UB temperature and 6.9 min of UB time at W/M-UB treatment and CP power: 22.176, UB temperature: 40.135 and UB time: 24.122 at CP-UB treatment. Oxygenated monoterpenes were also higher in the essential oils (EOs) of all three treated plant materials. In conclusion, the SEO extraction yield improved by the application of the pretreatments in optimized conditions.
ABSTRACT
This study aimed to evaluate the effects of micron sized non-thermal atmospheric pressure plasma inside the animal body on breast cancer tumor. The µ-plasma jet consists of micron sized hollow tube in which pure helium gas is ionized by high voltage (4 kV) and high frequency (6 kHz). The efficiency of the plasma treatment in killing cancer cells was first investigated by cell viability measurements of treated 4T1 cells using flow cytometry and cell cycle analysis. For exploration of the in vivo effects of the plasma treatment, the BALB/c mice inoculated by 4T1 cell lines were exposed subcutaneously to plasma for 3 minutes. In addition, H&E staining, TUNEL and Western blotting assays were performed in order to observed the effects of the non-thermal plasma on the tumor cells. The results showed that the efficiency of the plasma in suppression of the tumor growth is comparable to that of a typical chemotherapy drug. Moreover, the results indicated that the plasma induces apoptosis in the tumor tissue and increases the ratio of the apoptotic to anti-apoptotic protein expression. We believe that these findings presented herein may extend our knowledge of the mechanisms by which the plasma exerts its promising anti-cancer effects.
Subject(s)
Apoptosis Regulatory Proteins/genetics , Breast Neoplasms/therapy , Helium/therapeutic use , Plasma Gases/therapeutic use , Animals , Apoptosis/genetics , Atmospheric Pressure , Breast Neoplasms/genetics , Breast Neoplasms/pathology , Cell Line, Tumor , Cell Survival , Disease Models, Animal , Female , Gene Expression Regulation, Neoplastic/genetics , Helium/chemistry , Humans , In Situ Nick-End Labeling , Mice , Plasma Gases/chemistryABSTRACT
Non-thermal plasma (NTP) has been introduced over the last few years as a promising after- treatment system for nitrogen oxides and particulate matter removal from diesel exhaust. NTP technology has not been commercialised as yet, due to its high rate of energy consumption. Therefore, it is important to seek out new methods to improve NTP performance. Residence time is a crucial parameter in engine exhaust emissions treatment. In this paper, different electrode shapes are analysed and the corresponding residence time and NOx removal efficiency are studied. An axisymmetric laminar model is used for obtaining residence time distribution numerically using FLUENT software. If the mean residence time in a NTP plasma reactor increases, there will be a corresponding increase in the reaction time and consequently the pollutant removal efficiency increases. Three different screw thread electrodes and a rod electrode are examined. The results show the advantage of screw thread electrodes in comparison with the rod electrode. Furthermore, between the screw thread electrodes, the electrode with the thread width of 1 mm has the highest NOx removal due to higher residence time and a greater number of micro-discharges. The results show that the residence time of the screw thread electrode with a thread width of 1 mm is 21% more than for the rod electrode.
