High throughput cellular biosensor for the ultra-sensitive,ultra-rapid detection of aflatoxin M1

The aim of this study was the development of a rapid novel biosensor system based on the Bioelectric Recognition Assay (BERA) for the detection of aflatoxin M1 (AFM1). Membrane-engineering was achieved by electroinsertion of AFM1-homologous antibodies into the membrane of the cells. The sensor measured the electric response of cultured membrane-engineered fibroblast cells suspended in an alginate gel matrix due to the change of their membrane potential after the interaction of the analyte molecules with the antibodies. The BERA-based sensor was able to detect AFM1 rapidly (3min) at very low concentrations (5 pg/ml = 5 ppt), thus demonstrating a higher sensitivity than most currently available biosensor-based methods. In addition, the assay was quite selective against other aflatoxins, such as aflatoxin B1 and ochratoxin A. Furthermore, the assay system allowed for high throughput AFM1 analysis (160 individual tests/h), due to its multiple cell–electrode interface array. Although further research is required for the optimization of the assay, the elimination of possible matrix effects and its validation by assaying actual food samples, this novel biosensor offers new perspectives for ultra-rapid, ultra-sensitive and low-cost monitoring of mycotoxins in food commodities.     

Spatiotemporal analysis of human activities for biometric authentication

This paper presents a novel framework for unobtrusive biometric authentication based on the spatiotemporal analysis of human activities. Initially, the subject’s actions that are recorded by a stereoscopic camera, are detected utilizing motion history images. Then, two novel unobtrusive biometric traits are proposed, namely the static anthropometric profile that accurately encodes the inter-subject variability with respect to human body dimensions, while the activity related trait that is based on dynamic motion trajectories encodes the behavioral inter-subject variability for performing a specific action. Subsequently, score level fusion is performed via support vector machines. Finally, an ergonomics-based quality indicator is introduced for the evaluation of the authentication potential for a specific trial. Experimental validation on data from two different datasets, illustrates the significant biometric authentication potential of the proposed framework in realistic scenarios, whereby the user is unobtrusively observed, while the use of the static anthropometric profile is seen to significantly improve performance with respect to state-of-the-art approaches.     

How student’s personality traits affect Computer Based Assessment Acceptance: Integrating BFI with CBAAM

Researchers in the Information Systems (IS) field have put considerable effort on identifying how personality affects technology acceptance. This study is a further step towards this direction within the context of Computer Based Assessment (CBA). Particularly, it investigates how the five personality factors affect the most important variables regarding CBA’s acceptance. For this purpose, 117 participants were required to complete a survey questionnaire. The questionnaire included the Big Five Inventory (BFI) questions in order to measure the five personality traits, and 23 items regarding student’s perceptions. Partial Least Squares (PLS) was used to test the measurement and the structural model. Results underline that Neuroticism has significant negative effect on Perceived Usefulness and on Goal Expectancy, Agreeableness determines Social Influence and Perceived Ease of Use, Conscientiousness defines Perceived Ease of Use, while Extroversion and Openness explain Perceived Importance. Important implications of these results are discussed.     

A compound real option and AHP methodology for evaluating ICT business alternatives

After the liberalization of information and communication technology (ICT) markets many potential providers have appeared. Thus, business complexity, for ICT decision makers, has increased. In this paper, we focus on the problem of selecting the optimal business evolution path for ICT, focusing on the broadband technology (BT) field. Traditional quantitative cost–benefits analysis, such as net present value (NPV), is by no means sufficient for capturing the complexity of the problem in its entire. Researchers suggest the real options (ROs) for valuating ICT investments. However, RO models are strictly quantitative and very often ICT investments may also contain qualitative factors, which cannot be quantified in monetary terms. In addition, ROs analysis itself brings to the “surface” some factors that can be more efficiently treated qualitatively. We combine the ROs and analytic hierarchy process (AHP) into a common decision analysis framework providing an integrated multicriteria model, called ROAHP, for prioritizing ICT business alternatives. The proposed model is applied to a real life BT business case, showing how it can be formulated and solved.     

Experimental investigation of R-ratio effects on fatigue crack growth of adhesively-bonded pultruded GFRP DCB joints under CA loading

A series of fatigue experiments was performed in order to investigate the effect of the R-ratio on the fatigue/fracture behavior of adhesively-bonded pultruded GFRP double cantilever beam joints. Constant amplitude fatigue experiments were carried out under displacement control with a frequency of 5 Hz in ambient laboratory conditions. Three different R-ratios were applied: R = 0.1, R = 0.5 and R = 0.8. The crack length was determined by means of crack gages and a dynamic compliance method. The dominant failure mode was a fiber-tear failure that occurred in the mat layers of the pultruded laminates. The depth of the crack location significantly affected the energy dissipated for the fracture under cyclic loading. Short-fiber and roving bridging increased the fracture resistance during crack propagation. Fatigue crack growth curves were derived for each R-ratio and each observed crack path location. The fatigue threshold and slope of the fatigue crack growth curve significantly increased with increased R-ratio.     

Correction to: Automatic stress analysis from facial videos based on deep facial action units recognition

Pattern Analysis and Applications - A correction to this paper has been published: 10.1007/s10044-021-01012-9     

Development of a decision support tool for the assessment of biofuels

Alternative fuels for the transport sector are gaining growing attention as a means against fossil fuel dependence and towards greener forms of energy. At the same time, however, they are surrounded with doubts concerning sustainability of their production. This work presents the basic framework for a decision support tool to evaluate biofuel production pathways, with the purpose of providing the decision maker with a structured methodology that will lead him to the final decision. The tool integrates the most important aspects along the entire value chain (i.e. from biomass production to biofuel end-use), namely the technical, economic, environmental and social aspect. The tool consists of a computational part, which can be combined with the personal preferences of the user. The analysis provides a score for the respective pathway that can be used to rank different options and select among them the optimal solution. The functionality of the tool has been tested for the case of biodiesel from rapeseed in Germany.     

A study of in situ plated tin-film electrodes for the determination of trace metals by means of square-wave anodic stripping voltammetry

This work is a study of tin-film electrodes (SnFEs) for the determination of trace metals by means of square-wave anodic stripping voltammetry (SWASV). SnFEs represent a new promising type of environment-friendly electrodes but their analytical performance has not been explored in detail so far. Initially, the operational parameters for the simultaneous determination of Cd(II) and Zn(II) on in situ plated SnFEs on different substrates were thoroughly investigated. Using the selected conditions, at a preconcentration time of 120 s the limits of detection were 0.7 μg l⁻¹ for Cd and 0.9 μg l⁻¹ for Zn and the percent relative standard deviations were 4.2% for Zn(II) and 3.6% for Cd(II) at the 20 μg l⁻¹ level (n = 8). Subsequently, a study was conducted to investigate the utility of SnFEs as sensors for the determination of other metals, including those with oxidation potentials close to, or more positive than, the oxidation potential of Sn (Tl(I), Pb(II), Cu(II)). Finally, the SnFEs were successfully applied for the determination of Pb(II) and Zn(II) in tap water.     

Effect of heat treatment on internal atmosphere and leaf extension of minimally processed leek stalks

Leeks trimmed at 20 cm from their base were immersed in a 55 °C hot water bath. During the heat treatment (HT), the internal gases released from each stalk were collected, and their volume as well as CO₂ and O₂ concentrations were determined. After HT, cooling and storage at 10 °C for 8 days, the weight, maximum leaf extension and internal atmosphere (volume and gas composition) were measured. It was found that HT inhibited leaf extension during storage at 10 °C for 8 days and induced significant modification of the stalk internal atmosphere, both immediately after HT and after storage. Therefore, in heat‐treated leek stalks, the growth zone of the innermost leaves was subjected to an environment of elevated CO₂ concentration, which was accompanied by the inhibition of leaf extension growth.