Chitosan extracted from the Persian Gulf chiton shells: Induction of apoptosis in liver cancer cell line

Here for the first time, we investigated the cytotoxic effects of the chitosan extracted from the Persian Gulf Chiton shell (Acanthopleura vaillantii) on liver cancer cell line (HepG_2). Chitosan extraction was implemented following this method: chitin was produced by demineralization and deproteinization procedure, and the extracted chitin was converted into soluble chitosan using deacetylation method. The cytotoxic effects of extracted chitosan were evaluated using four different tests, including 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Annexin V-FITC, propidium iodide (PI) staining, 4',6-diamidino-2-phenylindole (DAPI) staining, and Caspase activity analysis. The IC_50 inhibitory concentrations of chitosan were obtained at 250 µg/mL after 24 h. Chitosan clearly inhibited the growth of hepatocarcinoma cells in vitro in a dose-dependent manner. For detecting the induced cell apoptosis, HepG_2 cells were treated with 125, 250 and 500 µg/ml of chitosan for 24 h. According to the result of Annex in V/PI kit, in 125, 250, and 500 µg/ml of chitosan, 28.2, 49.1, and 83.3% of HepG_2 cells undergone late apoptosis, respectively. The morphology of treated cells by DAPI staining showed non uniform plasma membrane and DNA fragmentation compared to untreated cells with perfect nucleus. The analysis of cell cycle using flow cytometry demonstrated that the rate of sub-G1 peak was increased to 52.7%. Both caspase-3 and -9 activities increased by the extracted chitosan, but it was only significant for caspase-3. The results of the present study suggested that the extracted chitosan has efficient cytotoxicity on HepG_2 cells. Therefore, the extracted chitosan from the shell of the Chiton may be considered as a futuristic natural product regarding the treatment of liver cancer

Simulation-based optimization of electrohydrodynamic drying of biological materials

LAUREA MAGISTRALEElectrohydrodynamic (EHD) drying is an effective non-thermal drying technology. Here the dehydration rate of the food product is enhanced by invoking ionic wind via a high voltage difference between the emitter and collector electrodes. Among various conventional emitter-collector configurations used for EHD drying, the wire-to-mesh configuration has recently been found to be promising in terms of drying kinetics, drying uniformity and scalability, compared to the conventional wire-to-plate configuration. This study aims to further enhance the potential of this promising collector design for EHD drying, by providing a next step in improving the collector electrode, to speed up the drying rate and increase. Mechanistic modeling is used to build a more realistic model of the mesh collector than currently used. In the first part, the major driving force for EHD drying are gathered and discussed, as a basis for further model improvements and to get an increased insight in this promising but complex drying technology. In the second part of this computational-theoretical study, the impact of various mesh parameters (wire diameter, wire number and porosity) on the electric field intensity, the resulting Coulomb force on the air flow and the drying rate was explored. To identify tradeoffs between drying rate, energy consumption and fluid mechanic losses, an EHD performance number is introduced. This allows having a comprehensive evaluation of energy efficiency and drying effectiveness of different device designs. In the last part, a more optimal mesh configuration is proposed that improves the overall EHD drying performance number. This improvement was achieved by using a lower number of conducting wires. Their number was chosen in such a way that an intensification of the electric field was obtained, based on an in-depth analysis of the electrostatic conditions. With this optimal configuration, a similar drying rate was obtained, but the resulting energy consumption was reduced with almost a factor 10. This improved mesh collector design is an important step towards EHD drying devices that are scalable to industrial scale, which are sufficiently clean and efficientElectrohydrodynamic (EHD) drying is an effective non-thermal drying technology. Here the dehydration rate of the food product is enhanced by invoking ionic wind via a high voltage difference between the emitter and collector electrodes. Among various conventional emitter-collector configurations used for EHD drying, the wire-to-mesh configuration has recently been found to be promising in terms of drying kinetics, drying uniformity and scalability, compared to the conventional wire-to-plate configuration. This study aims to further enhance the potential of this promising collector design for EHD drying, by providing a next step in improving the collector electrode, to speed up the drying rate and increase. Mechanistic modeling is used to build a more realistic model of the mesh collector than currently used. In the first part, the major driving force for EHD drying are gathered and discussed, as a basis for further model improvements and to get an increased insight in this promising but complex drying technology. In the second part of this computational-theoretical study, the impact of various mesh parameters (wire diameter, wire number and porosity) on the electric field intensity, the resulting Coulomb force on the air flow and the drying rate was explored. To identify tradeoffs between drying rate, energy consumption and fluid mechanic losses, an EHD performance number is introduced. This allows having a comprehensive evaluation of energy efficiency and drying effectiveness of different device designs. In the last part, a more optimal mesh configuration is proposed that improves the overall EHD drying performance number. This improvement was achieved by using a lower number of conducting wires. Their number was chosen in such a way that an intensification of the electric field was obtained, based on an in-depth analysis of the electrostatic conditions. With this optimal configuration, a similar drying rate was obtained, but the resulting energy consumption was reduced with almost a factor 10. This improved mesh collector design is an important step towards EHD drying devices that are scalable to industrial scale, which are sufficiently clean and efficien

Improving the rheometry of rubberized bitumen: experimental and computation fluid dynamics studies

Multi-phase materials are common in several fields of engineering and rheological measurements are intensively adopted for their development and quality control. Unfortunately, due to the complexity of these materials, accurate measurements can be challenging. This is the case of bitumen-rubber blends used in civil engineering as binders for several applications such as asphalt concrete for road pavements but recently also for roofing membranes. These materials can be considered as heterogeneous blends of fluid and particles with different densities. Due to this nature the two components tends to separate and this phenomenon can be enhanced with inappropriate design and mixing. This is the reason behind the need of efficient dispersion and distribution during their manufacturing and it also explains while realtime viscosity measurements could provide misleading results. To overcome this problem, in a previous research effort, a Dual Helical Impeller (DHI) for a Brookfield viscometer was specifically designed, calibrated and manufactured. The DHI showed to provide a more stable trend of measurements and these were identified as being ‘‘more realistic” when compared with those obtained with standard concentric cylinder testing geometries, over a wide range of viscosities. However, a fundamental understanding of the reasons behind this improvement is lacking and this paper aims at filling these gaps. Hence, in this study a tailored experimental programme resembling the bitumen-rubber system together with a bespoke Computational Fluid Dynamics (CFD) model are used to provide insights into DHI applicability to perform viscosity measurements with multiphase fluids as well as to validate its empirical calibration procedure. A qualitative comparison between the laboratory results and CFD simulations proved encouraging and this was enhanced with quantitative estimations of the mixing efficiency of both systems. The results proved that CFD model is capable of simulating these systems and the obtained simulations gave insights into the flow fields created by the DHI. It is now clear that DHI uses its inner screw to create a vertical dragging of particles within a fluid of lower density, while the outer screw transports the suspended particles down. This induced flow helps keeping the test sample less heterogeneous and this in turns allows recording more stable viscosity measurements

Quality evaluation of house cricket flour processed by electrohydrodynamic drying and pulsed electric fields treatment

House crickets are expected to play a significant role in the future food sector. Electrohydrodynamic (EHD) drying offers an environmentally friendly alternative to conventional drying methods. Pulsed electric fields (PEF) is a non-thermal process that facilitates conventional processes. EHD was applied to house crickets with and without PEF pretreatment, and the effect of PEF and EHD on the quality of the insects was evaluated. PEF pretreatment positively affected the oven drying at 60 °C by reducing its duration and thus decreasing the energy consumption by 14.22%. Moisture removal of EHD was not sufficient to replace oven drying, but when combined with oven drying, the overall energy consumption was reduced by >50%. PEF processing also increased the protein solubility (53.07% higher than the respective control) and antioxidant activity (24.05% higher than the respective control) of the oven-dried samples and reduced the histamine content of the EHD-dried samples (25.87% lower than the respective control)

Biorremediação de Solos Contaminados por Cádmio e Cromo, pelo Anelídeo Eisenia fetida

One of the most important environmental problems in the world is the soils contamination by heavy metals in the industrial areas, and especially the contamination of the agricultural lands. The use of earthworms to bioremediate the soils results in reducing the pollutants concentration through a bioaccumulation mechanism on the contaminants in the earthworm\u27s body. Hence, the present study aimed to prove the biological effectiveness of Eisenia fetida earthworms in bioremediation the soils contaminated with chromium and cadmium. Concentration of chromium and cadmium pollution in soil was determined to be 0.04 mg/g and 0.08 mg/g respectively. 30 worms were added to 500 g soil samples. Chromium and cadmium concentration in soil and in the body of worms was measured at two time periods of 21 and 42 days. To measure the concentration of chromium and cadmium we used ICP spectrometry. Software in usage was SPSS version 17. There was a significant correlation between the reduction of chromium and cadmium metals in the soils and the accumulation of chromium and cadmium metals in the worm\u27s body. A significant decline of chromium levels of the soil was observed in the days 21 and 42 during the study compared to initial amount of 0.1 mg/g. on the other hand chromium concentration of the soil decreased from 0.14 mg/g to 0.1 mg/g after 42 days. Comparison of mortality in two different time periods showed that by passing the time and by increase in soil chromium and cadmium concentrations the death toll of worms rises. The increased mortality of worms in the soil at a concentration of 0.08 mg/g of chromium, say that using the worms for bioremediation is not recommended at such concentration of chromium but using the worms for the removal of cadmium at concentrations of 0.04 mg/g and 0.08 mg/g in the soil is recommended.Um dos problemas ambientais mais importantes do mundo é a contaminação dos solos por metais pesados nas áreas industriais e, principalmente, a contaminação das terras agrícolas. O uso de anelídeos para biorremediar os solos resultam na redução da concentração de poluentes por meio de um mecanismo de bioacumulação dos contaminantes no corpo dos anelídeos. Assim, o presente estudo teve como objetivo comprovar a eficácia biológica dos anelídeos Eisenia fetida em biorremediação dos solos contaminados com cromo e cádmio. A concentração de cromo e cádmio em solo poluídos foi determinadao como sendo 0,04 mg/g , e de 0,08 mg/g respectivamente. Trinta anelídeos foram adicionados a 500 g de amostras de solo. A concentração de cromo e cádmio no solo e no corpo dos anelídeos foi medida em dois períodos, de 21 e 42 dias . Para medir a concentração de cromo e cádmio usamos espectrometria de ICP . O software em uso foi o SPSS versão 17. Houve uma correlação significativa entre a redução dos metais cromo e cádmio nos solos e da acumulação de metais de cromo e cádmio no corpo dos anelídeos. Também houve uma diminuição significativa na concentração de cromo no solo após 21 e 42 dias em que a concentração inicial de 0,1 mg / g de solo e foi observada após 42 dias a 0,14 mg / g de concentração de crómio no solo diminuiu para 0,1 mg / g . A comparação de mortalidade em dois períodos de tempo diferentes mostraram que há o aumento de mortalidade com o aumento da concentração de cromo e cádmio no solo. O aumento da mortalidade de anelídeos no solo ocorre a uma concentração de 0,08 mg/g de crómio, o que indica que utilização dos anelídeos para a biorremediação não é recomendado em tal concentração de cromo, todavia seu uso é recomendado para a remoção de cádmio em concentrações de 0,04 mg / g e 0,08 mg / g no solo

Electron beam structuring of Ti6Al4V: New insights on the metal surface properties influencing the bacterial adhesion

Soft tissue adhesion and infection prevention are currently challenging for dental transmucosal or percutaneous orthopedic implants. It has previously been shown that aligned micro-grooves obtained by Electron Beam (EB) can drive fibroblast alignment for improved soft tissue adhesion. In this work, evidence is presented that the same technique can also be effective for a reduction of the infection risk. Grooves 10-30 \u3bcm wide and around 0.2 \u3bcm deep were obtained on Ti6Al4V by EB. EB treatment changes the crystalline structure and microstructure in a surface layer that is thicker than the groove depth. Unexpectedly, a significant bacterial reduction was observed. The surfaces were characterized by field emission scanning electron microscopy, X-ray diffraction, confocal microscopy, contact profilometry, wettability and bacterial adhesion tests. The influence of surface topography, microstructure and crystallography on bacterial adhesion was systematically investigated: it was evidenced that the bacterial reduction after EB surface treatment is not correlated with the grooves, but with the microstructure induced by the EB treatment, with a significant bacterial reduction when the surface microstructure has a high density of grain boundaries. This correlation between microstructure and bacterial adhesion was reported for the first time for Ti alloys

Electrohydrodynamic drying versus conventional drying methods: A comparison of key performance indicators

Preserving fruits and vegetables by drying is a traditional yet effective way of reducing food waste. Existing drying methods are either energy-intensive or lead to a significant reduction in product quality. Electrohydrodynamic (EHD) drying is an energy-efficient low-temperature drying method that presents an opportunity to comply with the current challenges of existing drying methods. However, despite its promising characteristics, EHD drying is yet to be accepted by industry and farmers. The adoption of EHD drying is hindered due to different reasons, such as uncertainties surrounding its scalability, quality of dried product, cost of operation, and sustainability compared to conventional drying methods. To address these concerns, this study quantifies and benchmarks the Key Performance Indicators (KPIs) of EHD drying compared to the standard conventional drying methods based on lab-scale experiments. These drying methods include hot-air, freeze, microwave, and solar drying. The results show that drying food using EHD is at least 1.6, 20, and 70 times more energy-efficient than the microwave, freeze, and hot-air, respectively. Similar results could be observed for exergy efficiency. EHD drying has superior product quality compared to other drying methods. For instance, it could retain 62% higher total phenolic content with 21% less color degradation than freeze-drying. Although microwave drying resulted in significantly higher drying kinetics than other techniques, EHD performed better than solar and freeze-drying but was comparable with hot-air drying. EHD drying also shows promising results in economic performance assessment. It is the cheapest drying method after solar drying and has the highest estimated net present value (NPV) after hot-air drying. Overall, compared to the currently used drying methods for small to medium-scale drying, EHD was found to be a more exergy and energy-efficient, cost-effective, and sustainable alternative that can provide higher-quality dried products. However, its drying kinetics should be improved for industrial applications

A study on relationship between female employees’ organizational citizenship behavior and job satisfaction within organization

This paper presents an investigation to assess the relationship between female employees’ organizational citizenship behavior and job satisfaction within organization. A questionnaire is designed and distributed among employees who work in city of Qom, Iran and after analyzing the responses by SPSS software program, the relationships between variables are assessed by Pearson test after confirming the normality of the data using Kolmogrov-Smirnov test. The results of the studies reflect a strong relationship between citizen-organization behavior of female employees and job satisfaction. In addition, the survey examines six sub-hypotheses and confirms that there are positive and meaningful relationships between female employees’ custom, altruism, work consciousness, mutual coordination, fairness and courtesy on one side and job satisfaction on the other side