Inactivation efficacy of plasma-activated water: influence of plasma treatment time,exposure time and bacterial species

This study aimed to evaluate the influence of plasma treatment time, bacterial exposure time to PAW and bacterial species on the inactivation efficacy of plasma-activated water (PAW), with additional investigation of the inactivation mechanisms of PAW. Six bacterial species, including Listeria innocua, Staphyloccus aureus, Escherichia coli, Pseudomonas fluorescens, Shewanella putrefaciens and Aeromonas hydrophila were selected as the representative bacteria. The initial bacterial concentration was around 7 log CFU ml⁻¹ after mixing with PAW, and the inactivation efficacy was measured after different exposure times during the 4 °C storage. Scanning electron microscopy (SEM) images of the bacteria after PAW treatment were carried out to inspect the cell structure damage, and physicochemical properties of PAW, including pH, conductivity and long-living reactive species of H₂O₂, , and , were examined. The results showed that the inactivation efficacy of PAW was positively correlated with plasma treatment time and bacterial exposure time, and for the species examined in this study, the Gram-negative species were more sensitive to PAW than the Gram-positive species. Cell structure damage, including shrinkage, distortion, or holes, was observed after PAW treatment. The pH of PAW was acidified to 2.5–2.9, and conductivity was significantly increased to 518.0 μs cm⁻¹. and H₂O₂ were reduced during the 48 h storage, while an increased concentration was observed for . This study demonstrated that the processing parameters of plasma treatment time, exposure time and characteristics of bacteria can significantly affect the inactivation efficacy of PAW.     

Synthesis,characterization of β-CD based novel hydrogels with dual objectives of drug release and dye removal

Iranian Polymer Journal - In our recent work, we have reported on hydrogels devoid of cross-linkers. After observing the successful swelling and water retention properties, we have introduced...     

The live cell irradiation and observation setup at SNAKE

We describe a new setup at the ion microprobe SNAKE (Superconducting Nanoscope for Applied nuclear (Kern-) physics Experiments) at the Munich 14 MV Tandem accelerator that facilitates both living cell irradiation with sub micrometer resolution and online optical imaging of the cells before and after irradiation by state of the art phase contrast and fluorescence microscopy. The cells are kept at standard cell growth conditions at 37 °C in cell culture medium. After irradiation it is possible to switch from single ion irradiation conditions to cell observation within 0.5 s. First experiments were performed targeting substructures of a cell nucleus that were tagged by TexasRed labeled nucleotides incorporated in the cellular DNA by 55 MeV single carbon ion irradiation. In addition we show first online sequences of short time kinetics of Mdc1 protein accumulation in the vicinity of double strand breaks after carbon ion irradiation.     

Understanding continuance usage of mobile shopping applications in India: the role of espoused cultural values and perceived risk

We drew on the unified theory of acceptance and use of technology (UTAUT2) model, and perceived risk construct to propose an integrated model to explain continuance usage of mobile shopping applications. Espoused national cultural values of individualism/collectivism, masculinity/femininity, power distance, uncertainty avoidance, and long-term/short-term orientation act as moderators to examine the influence of within-culture variation on app usage. Findings reveal habit as the strongest predictor of both continuance intention and use behaviour, but interestingly perceived risk did not influence the post-acceptance behaviour of users significantly. Individualism/collectivism, masculinity/femininity, and long-term/short-term orientation espoused cultural values significantly moderated the relationships in the model. Noteworthy theoretical and managerial implications of the research are discussed further.     

Identification of benzalkonium chloride in food additives and its inefficacy against bacteria in minced meat and raw sausage batters

There is a growing market for 'natural' food preservatives though their active ingredients are poorly known. We analysed four such additives, Bacterin, Protecta One, Protecta Two and Protecta Three, marketed as effective preservatives for meat products on the basis of salts and extracts of 'natural herbs'. Their ingredients were separated by HPLC and the structures of the antimicrobially active components were determined by mass spectrometry. The products contained the disinfectant benzalkonium chloride, an antimicrobial quaternary ammonium compound, as the only active principle. HPLC methods are reported for the analysis of benzalkonium chloride in such products and in meat. Bacterin and Protecta One, as well as pure benzalkonium chloride in equivalent concentrations, did not show antibacterial effects against meat-relevant pathogens in minced meat and raw sausage batter. Because benzalkonium chloride is not a permitted food additive, and is not effective as a preservative in meat, the public should be cautioned against such products alleged to contain 'natural herb extracts'.     

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Inactivation of staphylococcal enterotoxins by heat and reactivation by high pH treatment

Inactivation of staphylococcal enterotoxins (SE) added to different media upon heat treatment (80 degrees C or 100 degrees C for 10 min) and reactivation of inactivated SE was studied. In gelatin (pH 4.0), lettuce extract, peas and beans extracts and ovalbumin (pH 5.0) the immunological activity of SE was lost almost completely upon heating. The loss of immunological activity of SEA was accompanied by a concomitant loss of biological activity of this toxin (monkey feeding test). A high pH treatment (pH 11) of the different preparations restored both the immunological and biological activity in most samples tested. Heating at 80 degrees C or 100 degrees C for 10 min of SE containing gelatin (pH 7.0), cauliflower extract (pH 4.0 or pH 7.0), milk (pH 4.0), casein (pH 6.0), rice extract (pH 7.0), noodles extract (pH 4.0) and oat-flakes extract (pH 7.0) had a much lower effect on the immunological activity of the SE (activity greater than or equal to 25%).     

Identification of monofloral honey using voltammetric electronic tongue

Quality assessment of honey is often related to its floral origin which is a complex task to evaluate. Traditional technique of floral assessment is made by melissopalynological method. However, this method is quite time consuming and also often operator dependent. Thus, the fallout is a large range of error in interpretation of the result and hence there is considerable demand for instrumental methods to assess the identification of pollen in honey. In this pursuit, an electronic tongue based on cyclic voltammetry is developed to discriminate honey samples based on their floral types and is described in this paper. The technique has been investigated using platinum as the working electrode and the resultant current from the potentiostat has been considered for data analysis. The use of principal component analysis (PCA) and linear discriminate analysis (LDA) proves to be useful in clustering honey samples. Finally, classification performances are investigated using back-propagation multilayer perceptron (BP-MLP) and radial basis function (RBF) neural network models for identification of different floral origin of honey.