Environmentally-friendly technology for rapid identification and quantification of emerging pollutants from wastewater using infrared spectroscopy.

The monitoring of emerging pollutants in wastewaters is nowadays an issue of special concern, with the classical quantification methods being time and reagent consuming. In this sense, a FTIR transmission spectroscopy based chemometric methodology was developed for the determination of eight of these pollutants. A total of 456 samples were, therefore, obtained, from an activated sludge wastewater treatment process spiked with the studied pollutants, and analysed in the range of 200 cm-1 to 14,000 cm-1. Then, a k-nearest neighbour (kNN) analysis aiming at identifying each sample pollutant was employed. Next, partial least squares (PLS) and ordinary least squares (OLS) modelling approaches were employed in order to obtain suitable prediction models. This procedure resulted in good prediction abilities regarding the estimation of atrazine, desloratadine, paracetamol, ß-estradiol, ibuprofen, carbamazepine, sulfamethoxazole and ethynylestradiol concentrations in wastewaters. These promising results suggest this technology as a fast, eco-friendly and reagent free alternative methodology for the quantification of emerging pollutants in wastewaters.

Quantification of pharmaceutical compounds in wastewater samples by near infrared spectroscopy (NIR).

The quantification of pollutants, as pharmaceuticals, in wastewater is an issue of special concern. Usually, typical methods to quantify these products are time and reagent consuming. This paper describes the development and validation of a Fourier transform near-infrared (FT-NIR) spectroscopy methodology for the quantification of pharmaceuticals in wastewaters. For this purpose, 276 samples obtained from an activated sludge wastewater treatment process were analysed in the range of 200 cm-1 to 14,000 cm-1, and further treated by chemometric techniques to develop and validate the quantification models. The obtained results were found adequate for the prediction of ibuprofen, sulfamethoxazole, 17ß-estradiol and carbamazepine with coefficients of determination (R2) around 0.95 and residual prediction deviation (RPD) values above four, for the overall (training and validation) data points. These results are very promising and confirm that this technology can be seen as an alternative for the quantification of pharmaceuticals in wastewater.

New PLS analysis approach to wine volatile compounds characterization by near infrared spectroscopy (NIR).

This work aims to explore the potential of near infrared (NIR) spectroscopy to quantify volatile compounds in Vinho Verde wines, commonly determined by gas chromatography. For this purpose, 105 Vinho Verde wine samples were analyzed using Fourier transform near infrared (FT-NIR) transmission spectroscopy in the range of 5435 cm-1 to 6357 cm-1. Boxplot and principal components analysis (PCA) were performed for clusters identification and outliers removal. A partial least square (PLS) regression was then applied to develop the calibration models, by a new iterative approach. The predictive ability of the models was confirmed by an external validation procedure with an independent sample set. The obtained results could be considered as quite good with coefficients of determination (R2) varying from 0.94 to 0.97. The current methodology, using NIR spectroscopy and chemometrics, can be seen as a promising rapid tool to determine volatile compounds in Vinho Verde wines.

The Hoff circuit test is more specific than an incremental treadmill test to assess endurance with the ball in youth soccer players.

The assessment of aerobic endurance is important for training prescription in soccer, and is usually measured by straight running without the ball on a track or treadmill. Due to the ball control and technical demands during a specific soccer test, the running speeds are likely to be lower compared to a continuous incremental test. The aim of the present study was to compare the heart rate (HR), rating of perceived exertion (RPE) and speeds corresponding to 2.0 mmol∙L(-1), 3.5 mmol∙L(-1), lactate threshold (Dmax method) and peak lactate determined in the laboratory and in the Hoff circuit soccer-specific test. Sixteen soccer players (16±1 years) underwent two incremental tests (laboratory and Hoff circuit tests). The speeds were significantly higher in the treadmill test than on the Hoff circuit (2.0 mmol∙L(-1): 9.5±1.2 and 8.1±1.0 km∙h(-1); 3.5 mmol∙L(-1): 12.0±1.2 and 10.2±1.1 km∙h(-1); Dmax: 11.4±1.4 and 9.3±0.4 km∙h(-1); peak lactate: 14.9±1.6 and 10.9±0.8 km∙h(-1)). The HR corresponding to 3.5 mmol∙L-1 was significantly higher on the Hoff circuit compared to the laboratory test (187.5±18.0 and 178.2±17.6 bpm, respectively; P <0.001), while the RPE at the last incremental stage was lower on the Hoff circuit (P < 0.01). The speeds during the Hoff specific soccer test and the HR corresponding to 2.0 mmol∙L(-1), 3.5 mmol∙L(-1) and Dmax/threshold were different compared with the laboratory test. The present study shows that it is possible to assess submaximal endurance related variables specifically in soccer players.

Quantitative image analysis as a tool for Yarrowia lipolytica dimorphic growth evaluation in different culture media.

Yarrowia lipolytica, a yeast strain with a huge biotechnological potential, capable to produce metabolites such as γ-decalactone, citric acid, intracellular lipids and enzymes, possesses the ability to change its morphology in response to environmental conditions. In the present study, a quantitative image analysis (QIA) procedure was developed for the identification and quantification of Y. lipolytica W29 and MTLY40-2P strains dimorphic growth, cultivated in batch cultures on hydrophilic (glucose and N-acetylglucosamine (GlcNAc) and hydrophobic (olive oil and castor oil) media. The morphological characterization of yeast cells by QIA techniques revealed that hydrophobic carbon sources, namely castor oil, should be preferred for both strains growth in the yeast single cell morphotype. On the other hand, hydrophilic sugars, namely glucose and GlcNAc caused a dimorphic transition growth towards the hyphae morphotype. Experiments for γ-decalactone production with MTLY40-2P strain in two distinct morphotypes (yeast single cells and hyphae cells) were also performed. The obtained results showed the adequacy of the proposed morphology monitoring tool in relation to each morphotype on the aroma production ability. The present work allowed establishing that QIA techniques can be a valuable tool for the identification of the best culture conditions for industrial processes implementation.

Association between HLA-C*04 and American cutaneous leishmaniasis in endemic region of southern Brazil.

Leishmaniasis is a parasitic infectious disease with global repercussions. American cutaneous leishmaniasis (ACL) is endemic in southern Brazil and its pathogenesis varies according to parasite species, immune response, and host genetics. In terms of immunogenetics, many host genes, including HLA (human leukocyte antigen), could be involved in susceptibility to and protection against ACL. Accordingly, the aim of this study was to investigate the association between HLA class I genes (HLA-A, -B, and -C) and ACL in an endemic region of southern Brazil. The allele frequencies of 186 patients diagnosed with ACL and 278 healthy individuals were compared. HLA class I (HLA-A, -B, and -C) typing was carried out by PCR-SSO using Luminex technology. The results revealed an association between the HLA-C*04 allele and the patient study group, in which it appeared more frequently than in the control group [21.5 vs 13.49% (P = 0.0016 and Pc = 0.0258; OR = 1.7560; 95%CI = 1.2227-2.5240)], thereby suggesting an increased susceptibility to ACL. Additional allelic groups such as HLA-A*02, HLA-B*35, HLA-B*45, HLA-C*01, and HLA-C*15 were also implicated; however, further investigation is necessary to confirm their association with ACL. Therefore, the results obtained in this study demonstrate the involvement of HLA class I genes in the susceptibility or resistance to ACL, with significant association between HLA-C*04 and ACL susceptibility.

Ability of immunodiagnostic tests to differentiate between dogs naturally infected with Leishmania infantum and Leishmune(®)-vaccinated dogs.

Visceral leishmaniasis (VL) is a serious chronic disease with a lethality rate of up to 10% in humans. In urban areas of Brazil, dogs are the main reservoirs of the etiological agent (Leishmania infantum) of VL, and the Brazilian Ministry of Health recommends the euthanasia of animals that are seropositive in both the immunochromatographic dual path platform rapid test (DPP(®); Bio-Manguinhos) and the enzyme-linked immunosorbent assay (ELISA) with an L. major-like antigen (Bio-Manguinhos). Vaccination is an additional tool in the control of canine VL, but the use of Leishmune(®) (Zoetis Indústria de Produtos Veterinários, São Paulo, SP, Brazil), which contains the fucose mannose ligand (FML) isolated from L. donovani, is not currently recommended by the Brazilian Ministry of Health because vaccinated animals may exhibit positive serology and there are reservations regarding the efficacy of the vaccine. The aims of the present study were: (i) to verify the abilities of the fast agglutination screening test (FAST), the direct agglutination test (DAT), the indirect fluorescent-antibody test (IFAT), the DPP rapid test, and ELISA tests with L. major-like and FML antigens to differentiate between L. infantum-infected and Leishmune(®)-vaccinated dogs, and (ii) to analyze the sensitivities and specificities of the different methods. The reactivities to these tests of Leishmune(®)-vaccinated dogs (n = 71), asymptomatic (n = 20) and symptomatic (n = 20) naturally infected dogs, and unvaccinated healthy control dogs (n = 5) were compared. None of the Leishmune(®)-vaccinated dogs tested seropositive in FAST and DAT, although one dog was reactive to DPP and four dogs to ELISA/L. major-like and IFAT tests. While 69 (97%) of vaccinated dogs reacted to ELISA/FML, only one was seropositive in both ELISA/L. major-like and IFAT tests. Individually, all immunodiagnostic tests presented high specificities and positive likelihood ratios (LR+), and high specificity values were obtained when the tests were considered in pairs. However, sensitivity and LR- values were low for ELISA/L. major-like and IFAT tests individually, and for all pair combinations of tests except for FAST with DPP.

Risk factors associated with toxoplasmosis and toxocariasis in populations of children from nine cities in southern Brazil.

This study investigated the epidemiological factors that contribute to the seroprevalence of Toxoplasma gondii and Toxocara spp. in children from Paraná state, Brazil. Immunoglobulin G (IgG) antibodies to T. gondii were detected using indirect immunofluorescence, and IgG antibodies to Toxocara were detected using an enzyme-linked immunosorbent assay. For each individual, a questionnaire was completed that contained epidemiological and clinical data. The data analysis was performed using multiple logistic regression. Of the 544 children investigated, 3.2% presented co-infection with T. gondii and Toxocara spp. Of this total, 7.4% were positive for antibodies to T. gondii, and 25% were positive for antibodies to Toxocara spp. The presence of antibodies to Toxocara spp. increased the risk of T. gondii infection (P = 0.029). Children who were 1-8 years of age were less infected by T. gondii than those who were 9-12 years of age. The variables that influenced positivity for anti-Toxocara spp. were the origin of the children and contact with sand. Children with positive serology for Toxocara spp. presented more eosinophilia compared with those with non-reactive serology. Infection with both parasites reveals the need for preventive measures, such as guidance about modes of infection, parasite control and monitoring recreational areas.

Quantitative image analysis for the characterization of microbial aggregates in biological wastewater treatment: a review.

Quantitative image analysis techniques have gained an undeniable role in several fields of research during the last decade. In the field of biological wastewater treatment (WWT) processes, several computer applications have been developed for monitoring microbial entities, either as individual cells or in different types of aggregates. New descriptors have been defined that are more reliable, objective, and useful than the subjective and time-consuming parameters classically used to monitor biological WWT processes. Examples of this application include the objective prediction of filamentous bulking, known to be one of the most problematic phenomena occurring in activated sludge technology. It also demonstrated its usefulness in classifying protozoa and metazoa populations. In high-rate anaerobic processes, based on granular sludge, aggregation times and fragmentation phenomena could be detected during critical events, e.g., toxic and organic overloads. Currently, the major efforts and needs are in the development of quantitative image analysis techniques focusing on its application coupled with stained samples, either by classical or fluorescent-based techniques. The use of quantitative morphological parameters in process control and online applications is also being investigated. This work reviews the major advances of quantitative image analysis applied to biological WWT processes.

Characterization of activated sludge abnormalities by image analysis and chemometric techniques.

This work focuses on the use of chemometric techniques for identifying activated sludge process abnormalities. Chemometric methods combined with image analysis can improve activated sludge systems monitoring and minimize the need of analytical measurements. For that purpose data was collected from aggregated and filamentous biomass, biomass composition on Gram-positive/Gram-negative bacteria and viable/damaged bacteria, and operational parameters. Principal component analysis (PCA) was subsequently applied to identify activated sludge abnormalities, allowing the identification of several disturbances, namely filamentous bulking, pinpoint flocs formation, and zoogleal bulking as well as normal conditions by grouping the collected samples in corresponding clusters.

Identifying different types of bulking in an activated sludge system through quantitative image analysis.

The present study proposes an image analysis methodology for the identification of different types of disturbances in wastewater treatment activated sludge systems. Up to date, most reported image analysis methodologies have been used in activated sludge processes with the aim of filamentous bulking detection, however, other disturbances could be foreseen in wastewater treatment plants. Such disturbances can lead to fluctuations in the biomass contents, affecting the mixed liquor suspended solids (MLSS), and in the sludge settling ability, affecting the sludge volume index (SVI). Therefore, this work focuses on predicting the MLSS and SVI parameters for different types of disturbances affecting an activated sludge system. Four experiments were conducted simulating filamentous bulking, zoogleal or viscous bulking, pinpoint floc formation, and normal operating conditions. Alongside the MLSS and SVI determination, the aggregated and filamentous biomass contents and morphology were studied as well as the biomass Gram and viability status, by means of image analysis.

Critical perspective on the consequences of the limited availability of kinetic data in metabolic dynamic modelling.

Detailed kinetic models at the network reaction level are usually constructed using enzymatic mechanistic rate equations and the associated kinetic parameters. However, during the cellular life cycle thousands of different reactions occur, which makes it very difficult to build a detailed large-scale ldnetic model. In this work, we provide a critical overview of specific limitations found during the reconstruction of the central carbon metabolism dynamic model from E. coli (based on kinetic data available). In addition, we provide clues that will hopefully allow the systems biology community to more accurately construct metabolic dynamic models in the future. The difficulties faced during the construction of dynamic models are due not only to the lack of kinetic information but also to the fact that some data are still not curated. We hope that in the future, with the standardization of the in vitro enzyme protocols the approximation of in vitro conditions to the in vivo ones, it will be possible to integrate the available kinetic data into a complete large scale model. We also expect that collaborative projects between modellers and biologists will provide valuable kinetic data and permit the exchange of important information to solve most of these issues.

Dilution and magnification effects on image analysis applications in activated sludge characterization.

The properties of activated sludge systems can be characterized using image analysis procedures. When these systems operate with high biomass content, accurate sludge characterization requires samples to be diluted. Selection of the best image acquisition magnification is directly related to the amount of biomass screened. The aim of the present study was to survey the effects of dilution and magnification on the assessment of aggregated and filamentous bacterial content and structure using image analysis procedures. Assessments of biomass content and structure were affected by dilutions. Therefore, the correct operating dilution requires careful consideration. Moreover, the acquisition methodology comprising a 100× magnification allowed data on aggregated and filamentous biomass to be determined and smaller aggregates to be identified and characterized, without affecting the accuracy of lower magnifications regarding biomass representativeness.

Selection and characterization of a multivalent Salmonella phage and its production in a nonpathogenic Escherichia coli strain.

We report the selection and amplification of the broad-host-range Salmonella phage phi PVP-SE1 in an alternative nonpathogenic host. The lytic spectrum and the phage DNA restriction profile were not modified upon replication in Escherichia coli Bl21, suggesting the possibility of producing this phage in a nonpathogenic host, contributing to the safety and easier approval of a product based on this Salmonella biocontrol agent.

A Comparison between bright field and phase-contrast image analysis techniques in activated sludge morphological characterization.

Different approaches using microscopy image analysis procedures were employed for characterization of activated sludge systems. The approaches varied mainly on the type of visualization and acquisition method used for collection of data. In this context, this study focused on the comparison of the two most common acquisition methods: bright field and phase-contrast microscopy. Images were acquired from seven different wastewater treatment plants for a combined period of two years. Advantages and disadvantages of each acquisition technique and the results are discussed. Bright field microscopy proved to be more simple and inexpensive and provided the best overall results.

Comparison of adsorption equilibrium of fructose, glucose and sucrose on potassium gel-type and macroporous sodium ion-exchange resins.

Adsorption equilibrium of fructose, glucose and sucrose was evaluated on sulfonated poly(styrene-co-divinylbenzene) cation-exchange resins. Two types of resins were used: potassium (K+) gel-type and sodium (Na+) macroporous resins. Influence of the cation and effect of the resin structure on adsorption were studied. The adsorption isotherms were determined by the static method in batch mode for mono-component and multi-component sugar mixtures, at 25 and 40 degrees C, in a range of concentrations between 5 and 250 g L(-1). All adsorption isotherms were fitted by a linear model in this range of concentrations. Sugars were adsorbed in both resins by the following order: fructose > glucose > sucrose. Sucrose was more adsorbed in the Na+ macroporous resin, glucose was identically adsorbed, and fructose was more adsorbed in the K+ gel-type resin. Data obtained from the adsorption of multi-component mixtures as compared to the mono-component ones showed a competitive effect on the adsorption at 25 degrees C, and a synergetic effect at 40 degrees C. The temperature increase conducted to a decrease on the adsorption capacity for mono-component sugar mixtures, and to an increase for the multi-component mixtures. Based on the selectivity results, K+ gel-type resin seems to be the best choice for the separation of fructose, glucose and sucrose, at 25 degrees C.

Correlation between sludge settling ability and image analysis information using partial least squares.

In the last years there has been an increase on the research of the activated sludge processes, and mainly on the solid-liquid separation stage, considered of critical importance, due to the different problems that may arise affecting the compaction and the settling of the sludge. Furthermore, image analysis procedures are, nowadays considered to be an adequate method to characterize both aggregated and filamentous bacteria, and increasingly used to monitor bulking events in pilot plants. As a result of that, in this work, image analysis routines were developed in Matlab environment, allowing the identification and characterization of microbial aggregates and protruding filaments. Moreover, the large amount of activated sludge data collected with the image analysis implementation can be subsequently treated by multivariate statistical procedures such as PLS. In the current work the implementation of image analysis and PLS techniques has shown to provide important information for better understanding the behavior of activated sludge processes, and to predict, at some extent, the sludge volume index. As a matter of fact, the obtained results allowed explaining the strong relationships between the sludge settling properties and the free filamentous bacteria contents, aggregates size and aggregates morphology, establishing relevant relationships between macroscopic and microscopic properties of the biological system.

Morphology and physiology of anaerobic granular sludge exposed to an organic solvent.

The use of quantitative image analysis techniques, together with physiological information might be used to monitor and detect operational problems in advance to reactor performance failure. Industrial organic solvents, such as White Spirit, are potentially harmful to granular sludge. In preliminary batch assays, 33 mg L(-1) of solvent caused 50% relative biomass activity loss. In an expanded granular sludge blanket reactor fed with 40 mg L(-1) of solvent, during 222h, the reactor performance seemed to be unaffected, presenting COD removal efficiency consistently >95%. However, in the last days of exposure, the biogas production and the methane content were inhibited. Afterwards, already during recovery phase, the COD removal efficiency decreased to 33%, probably because the reactor was underloaded and the biomass became saturated in solvent only at this stage. In the first hours of exposure the specific acetoclastic and the specific hydrogenotrophic methanogenic activities decreased 29% and 21%, respectively. The % of aggregates projected area with equivalent diameter (D(eq))>1mm decreased from 81% to 53%. The mean D(eq) of the aggregates > or =0.2mm decreased, as well as the settling velocity, showing that the granules experienced fragmentation phenomenon caused by the solvent shock load. The ratio between total filaments length and total aggregates projected area (LfA) increased 2 days before effluent volatile suspended solids, suggesting that LfA could be an early-warning indicator of washout events.

Monitoring of activated sludge settling ability through image analysis: validation on full-scale wastewater treatment plants.

In recent years, a great deal of attention has been focused on the research of activated sludge processes, where the solid-liquid separation phase is frequently considered of critical importance, due to the different problems that severely affect the compaction and the settling of the sludge. Bearing that in mind, in this work, image analysis routines were developed in Matlab environment, allowing the identification and characterization of microbial aggregates and protruding filaments in eight different wastewater treatment plants, for a combined period of 2 years. The monitoring of the activated sludge contents allowed for the detection of bulking events proving that the developed image analysis methodology is adequate for a continuous examination of the morphological changes in microbial aggregates and subsequent estimation of the sludge volume index. In fact, the obtained results proved that the developed image analysis methodology is a feasible method for the continuous monitoring of activated sludge systems and identification of disturbances.

Monitoring of fed-batch E. coli fermentations with software sensors.

Accurate monitoring and control of industrial bioprocess requires the knowledge of a great number of variables, being some of them not measurable with standard devices. To overcome this difficulty, software sensors can be used for on-line estimation of those variables and, therefore, its development is of paramount importance. An Asymptotic Observer was used for monitoring Escherichia coli fed-batch fermentations. Its performance was evaluated using simulated and experimental data. The results obtained showed that the observer was able to predict the biomass concentration profiles showing, however, less satisfactory results regarding the estimation of glucose and acetate concentrations. In comparison with the results obtained with an Extended Kalman Observer, the performance of the Asymptotic Observer in the fermentation monitoring was slightly better.