Biosensor technology: applications in microbial toxicology

This work describes the development of mediated amperometric biosensors that are able to monitor the metabolic activity of both single and mixed microbial populations, with applications in toxicity assessment and wastewater treatment plant protection. Biosensor systems have been constructed incorporating either the single-species eubacteria Escherichia coli or Pseudomonas putida, Bioseed®, or a mixture of activated sludge organisms from wastewater treatment plants, as the sensing components immobilised on disposable screen printed electrodes in stirred reaction vials. The biosensor approach is generic allowing for a wide range of microbial cell types to be employed. Appropriate bacterial species can be selected for specific sensor applications in order to confer validity and relevance to the test, hence the biosensor can be tailor-made to assess the toxicity in a particular environment and provide diagnostically valid and relevant results. The biosensors have been used to assess the toxicity of a standard toxicant and toxicant formulations and in blind testing of a range of industrial effluents, in parallel with a number of bioassays including Microtox® and activated sludge respiration inhibition. The biosensor results generally show significant correlation to the appropriate conventional toxicity tests. In this study, an activated sludge based biosensor assay was developed and used to assess the toxicity of industrial process and site effluents with the specific purpose of wastewater treatment plant protection. Data generated compared significantly with those from an activated sludge respiration inhibition test, with added advantages of rapidity, safety and ease of use

Using Spatial Data for Geo-Environmental Studies

The physically-based spatially-distributed model PROMET (Processes of Radiation, Mass and Energy Transfer) is applied to the Greater Damascus Basin, which is considered as one of the most important basins in Syria, to serve as a case study of using spatial data for Geo-environmental studies. Like most areas of the Middle East, the study area is characterized by large temporal and spatial variations in precipitation and by limited water resources. Due to the increasing water demand caused by the economic development and the rapid growth of population, the study area is expected to suffer from further water shortages in the future. This highlights the necessity of developing an integrated Decision Support System (DSS) to evaluate strategies for efficient and sustainable water resources management in the basin, taking into consideration global environmental changes and socio-economic conditions. The work presented here represents the first steps toward achieving this goal through applying a distributed hydrological model (an important component of any integrated DSS for water resources management) to the Greater Damascus Basin utilizing different types of spatial data used as time-dependent (e.g., meteorology) and time-independent (e.g., topography and soil) input parameters. The model PROMET, which was developed within the GLOWA-Danube project as part of the decision support system DANUBIA, is run on an hourly time step (for the period from 1991 to 2005) and a 180*180m spatial resolution to simulate the water and energy fluxes in this basin. The model is embedded within a raster-based GIS-structure which facilitates the integration of the diverse types of spatial data. The spatial information related to topography (such as elevation, slope, and exposition) as well as those related to runoff routing (such as upstream-area, channel width, and downstream proxel) are automatically extracted from Digital Elevation Model (Shuttle Radar Topography Mission, SRTM-90m DEM). The spatial patterns of the different land use/land cover classes are derived from remote sensing data (classification of a cloud-free LANDSAT 7 ETM+ image using the supervised classification algorithm). The spatial fields of meteorological input data are provided on an hourly basis through spatiotemporal interpolation of the measurements of the available weather stations. Spatial information about the soil texture is provided through generalization and aggregation of the soil type classes of the Soil Map of Syria (prepared by USAID) and transferring the soil types to texture classes. Several pedotransfer functions are then used to estimate the soil hydraulic properties for each soil texture class (and each soil layer) found in the study area. While plant physiological parameters (which are assumed to be static, such as minimum stomatal resistance) are estimated for each vegetation class using information taken from literature sources, the temporal evolution of Albedo and Leaf Area Index (LAI) are derived from five cloud-free LANDSAT-7 images acquired at different seasons of the year. The goodness of the results obtained by the model PROMET are verified and/or validated by comparing them either with their corresponding data observed in the filed or with remote sensing-derived information (e.g., snow cover). Two subcatchments are selected for the purpose of calculating the spatially-distributed annual water balances. The results indicate that the modelled mean annual runoff volume fits well with the measured discharge for both chosen subcatchment. In addition, the simulated discharge is compared to the observed one (at seven gauge stations) on a monthly basis, covering the whole simulation period (15 years). The results of the regression analysis for each of these gauge stations (with slope of regression line ranges from 0.79 to 1.04; coefficient of determination 0.69-0.90; and Nash-Sutcliffe Coefficient 0.73-0.95) indicate that there is a good correlation between simulated and observed monthly mean discharge volumes

Swirling pipeflow of non-Newtonian and particle-laden fluids

This thesis describes the application of novel swirl inducing pipe to various pipe configurations, when pumping a range of fluids and fluid / particle mixtures. An extensive experimental programme, incorporating particle image velocimetry and photography, was implemented using a pipe flow loop designed specifically for the purpose. Experimental data was obtained on the effect of a 4-lobe near-optimal swirl pipe on coal-water, sand-water and magnetite-water slurries of various particle size. Results indicated that swirl induction produced greater benefit for denser slurries and higher concentrations, and that swirl induced into slurries containing larger and denser particles decayed more rapidly. At low velocity, experimental data highlighted a reduction in the total pressure drop experienced across a 3.0m horizontal pipe section, a downward sloping section and vertical pipe bends, when the swirl-inducing pipe was present. PIV was used to measure the axial and tangential velocity of swirling flows downstream of a near-optimal swirl-inducing pipe. It was confirmed that a significant tangential velocity was generated when pumping water in the turbulent regime, however, when the fluid viscosity was increased, leading to laminar flow, no significant tangential velocity was detected

Reliability assessment of manufacturing systems: A comprehensive overview, challenges and opportunities

Reliability assessment refers to the process of evaluating reliability of components or systems during their lifespan or prior to their implementation. In the manufacturing industry, the reliability of systems is directly linked to production efficiency, product quality, energy consumption, and other crucial performance indicators. Therefore, reliability plays a critical role in every aspect of manufacturing. In this review, we provide a comprehensive overview of the most significant advancements and trends in the assessment of manufacturing system reliability. For this, we also consider the three main facets of reliability analysis of cyber–physical systems, i.e., hardware, software, and human-related reliability. Beyond the overview of literature, we derive challenges and opportunities for reliability assessment of manufacturing systems based on the reviewed literature. Identified challenges encompass aspects like failure data availability and quality, fast-paced technological advancements, and the increasing complexity of manufacturing systems. In turn, the opportunities include the potential for integrating various assessment methods, and leveraging data to automate the assessment process and to increase accuracy of derived reliability models

Mechanisms of action of polyhexamethylene biguanide-based biocides against non-enveloped virus

Human viral pathogens place a serious threat on the healthcare system. Adequate and efficient disinfection procedures minimise the incidence of surface contamination and viral disease transmission. Biocide type, environmental conditions and viral characteristics e.g. presence of envelope influence the disinfection effectiveness. Thus, understanding the mechanisms of virucidal action is essential for improving disinfection efficacy. PHMB has a wide range of antimicrobial activities, but its action against viruses has been mostly tested on enveloped viruses, which appeared to be inactivated. This project aimed at understanding the mechanisms of action of two PHMB-based biocides, VANTOCIL TG and COSMOCILIMCQ, against non-enveloped viruses including the bacteriophages MS2 and F116 used as model viruses, and the human Adenovirus type5. Biocides were tested in a suspension test at different conditions. Hydrophobicity tests, SDS-PAGE, DNA analysis, dynamic light scattering and transmission electron microscopy were performed. Suspension tests at 20 °C showed that PHMBs at 800 ppm reduced MS2 and Ad5 by 90. Higher reduction was achieved against Fl 16 99. Times of exposure did not increase the activity, whereas temperature had a great effect. At 30 °C 99.99 of MS2 was inactivated after 10 min the efficacy against Ad5 was also enhanced, but to minor extent. Despite a modest activity, PHMB interacted with the viral capsid producing damage which was very specific against Ad5. Viral aggregation played a key role in limiting virucidal efficacy of PHMB, especially concerning MS2. It is likely that the observed capsid damage caused the inactivation. However, the hypothesis of domain formation by PHMB and thus the inhibition of the virus-host interaction cannot be ruled out. The mechanism of binding PHMB molecules to the viruses was highly cooperative and occurred through first electrostatic and then hydrophobic forces. Concluding, it is the first time that PHMB-based biocides were shown to interact with viral capsid resulting in virucidal activity against non-enveloped viruses. However, such activity is reduced by formation of viral aggregates. Results supported also the use of MS2 as a surrogate of human RNA non-enveloped viruses

Improving land surface models with FLUXNET data

There is a growing consensus that land surface models (LSMs) that simulate terrestrial biosphere exchanges of matter and energy must be better constrained with data to quantify and address their uncertainties. FLUXNET, an international network of sites that measure the land surface exchanges of carbon, water and energy using the eddy covariance technique, is a prime source of data for model improvement. Here we outline a multi-stage process for "fusing" (i.e. linking) LSMs with FLUXNET data to generate better models with quantifiable uncertainty. First, we describe FLUXNET data availability, and its random and systematic biases. We then introduce methods for assessing LSM model runs against FLUXNET observations in temporal and spatial domains. These assessments are a prelude to more formal model-data fusion (MDF). MDF links model to data, based on error weightings. In theory, MDF produces optimal analyses of the modelled system, but there are practical problems. We first discuss how to set model errors and initial conditions. In both cases incorrect assumptions will affect the outcome of the MDF. We then review the problem of equifinality, whereby multiple combinations of parameters can produce similar model output. Fusing multiple independent and orthogonal data provides a means to limit equifinality. We then show how parameter probability density functions (PDFs) from MDF can be used to interpret model validity, and to propagate errors into model outputs. Posterior parameter distributions are a useful way to assess the success of MDF, combined with a determination of whether model residuals are Gaussian. If the MDF scheme provides evidence for temporal variation in parameters, then that is indicative of a critical missing dynamic process. A comparison of parameter PDFs generated with the same model from multiple FLUXNET sites can provide insights into the concept and validity of plant functional types (PFT) – we would expect similar parameter estimates among sites sharing a single PFT. We conclude by identifying five major model-data fusion challenges for the FLUXNET and LSM communities: (1) to determine appropriate use of current data and to explore the information gained in using longer time series; (2) to avoid confounding effects of missing process representation on parameter estimation; (3) to assimilate more data types, including those from earth observation; (4) to fully quantify uncertainties arising from data bias, model structure, and initial conditions problems; and (5) to carefully test current model concepts (e.g. PFTs) and guide development of new concepts

Heat-stable metagenomic carbonic andydrases and their use

The present invention relates to polypeptides having carbonic anhydrase activity and polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides