Modelling the effect of SMP production and external carbon addition on S-driven autotrophic denitrification

The aim of this study was to develop a mathematical model to assess the effect of soluble microbial products production and external carbon source addition on the performance of a sulfur-driven autotrophic denitrification (SdAD) process. During SdAD, the growth of autotrophic biomass (AUT) was accompanied by the proliferation of heterotrophic biomass mainly consisting of heterotrophic denitrifiers (HD) and sulfate-reducing bacteria (SRB), which are able to grow on both the SMP derived from the microbial activities and on an external carbon source. The process was supposed to occur in a sequencing batch reactor to investigate the effects of the COD injection on both heterotrophic species and to enhance the production and consumption of SMP. The mathematical model was built on mass balance considerations and consists of a system of nonlinear impulsive differential equations, which have been solved numerically. Different simulation scenarios have been investigated by varying the main operational parameters: cycle duration, day of COD injection and quantity of COD injected. For cycle durations of more than 15 days and a COD injection after the half-cycle duration, SdAD represents the prevailing process and the SRB represent the main heterotrophic family. For shorter cycle duration and COD injections earlier than the middle of the cycle, the same performance can be achieved increasing the quantity of COD added, which results in an increased activity of HD. In all the performed simulation even in the case of COD addition, AUT remain the prevailing microbial family in the reactor

Rhabdomyosarcoma mimicking lymphangioma: report of three cases

oai:eyereports.org:article/37We report three cases of proptosis, in children aged 6, 10 and 12, whereby in all cases the first clinical, radiologic and ultrasonographic diagnosis was lymphangioma, while the final anatomopathological diagnosis was rhabdomyosarcoma. In presence of a rapidly worsening exophthalmos or eyelid swelling in a child, an early correct diagnosis is very important. Imaging techniques play a very important role in the diagnosis, but are often inconclusive and an excisional biopsy (if feasible) must always be considere

Lamellar macular defects: are degenerative lamellar macular holes truly degenerative?

PurposeTo investigate morpho-functional changes after surgical treatment for ERM foveoschisis or lamellar macular hole (LMH), and to evaluate whether the two entities are associated with different healing processes and long-term outcomes.DesignRetrospective interventional case series.MethodsA total of 56 eyes, treated for lamellar macular defects and followed up for 24 months, were enrolled. The eyes were divided into two groups: 34 with ERM foveoschisis and 22 with LMH. Changes in the following features were evaluated and compared between the two groups: best-corrected visual acuity (BCVA), external limiting membrane (ELM) and ellipsoid zone (EZ) defects, central foveal thickness (CFT), and autofluorescence (FAF) diameter and area.ResultsAfter surgery, progressive BCVA improvement was observed with no significant difference between the two groups (p-value: 0.06). An increased number of eyes with intact outer-retinal layers was found both in the ERM foveoschisis and LMH groups. FAF diameter and area decreased significantly throughout the FU with no significant difference between the two groups (p-value: 0.2).ConclusionIn the present study, significant functional and microstructural improvements were observed after surgery for both ERM foveoschisis and LMH, demonstrating considerable repair potential in both types of lamellar defects. These findings question the true “degenerative” nature of LMH

new insights into the development and progression of geographic atrophy after full thickness autologous choroidal graft

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1H‐NMR metabolomic profiling of the crayfish Astacus leptodactylus subjected to polyphenol‐enriched diets

1H-NMR analysis of the hepatopancreas, muscle and haemolymph of Astacus leptodactylus after feeding with polyphenol-enriched diet is reported. 1H-NMR spectra of lipophilic extracts showed the presence of cholesterol, fatty acid residues, phospholipids and triglycerides. 1H-NMR spectra of aqueous extracts identified 35 metabolites in the hepatopancreas, 31 in the muscle and 22 in the haemolymph. A total of 20 metabolites (amino acids and their derivatives) were present in the hepatopancreas, the muscle and the haemolymph. A total of 10 metabolites were present in both the hepatopancreas and the muscle (five amino acids, 2-hydroxybutyrate, choline, myo-inositol, glycogen and uracil). 2-Hydroxyisobutyrate and creatine were present in both the hepatopancreas and the haemolymph. Phosphorylethanolamine, phosphocholine and fumarate were present only in the hepatopancreas and isoleucine only in the muscle. Statistical analysis showed that the percentage of weight gain was statistically higher in polyphenol-enriched diet groups compared to the control and that polyphenols had a stimulating effect on the general metabolism. No stress-related metabolites were higher in crayfish fed with polyphenol-enriched diet. Conversely, phosphatidylcholine, cholesterol and DHA, linked to resistance to environmental stress and diseases, were higher compared to the control diet. This study indicates that 1H-NMR is a useful tool to study the metabolomics in relation to diet differences

A MODELLING AND NUMERICAL STUDY OF S-BASED DENITRIFICATION SYSTEMS

This thesis work concerns the mathematical modeling of an innovative biological process for wastewater treatment and its global sensitivity analysis. The aim of the presented mathematical model is to evaluate the effect of production and consumption of soluble microbial products (SMP) and addition of an external carbon source during a sulfur-based autotrophic denitrification. Such compounds during elemental sulfur-based autotrophic denitrification promotes the natural growth of heterotrophic microbial families, which are mainly represented by denitrifiers and sulfate-reducing bacteria. First, a state of art of the biological process from both experimental and modelling points of view is provided. An overview on autotrophic denitrification driven by elemental sulfur is given as well as a critical analysis on the existing experimental and mathematical studies on the process investigated. Afterwards, the mathematical model proposed is accurately described in the second chapter, and all mathematical and biological assumptions are detailed. The process was supposed to occur in a sequencing batch reactor to investigate the effects of the COD injection and the time in which this injection occurs on all the processes considered. To model this reactor configuration, a system of nonlinear impulsive differential equations was defined to simulate a system undergoing to instantaneous changes after a continuous period. The equations were solved numerically. The model was tested under ideal conditions where the settling efficiency of the reactor is supposed to be perfect. The model was tested varying different parameters: cycle duration, day of the injection of external COD and quantity of COD added. Albeit the high amount of sludge produced, it appears that SMP are not able to significantly support sulfate reduction. However, when an adequate amount of external carbon source is provided, the system is able to remove high nitrate concentrations without having high sulfate concentrations in the effluent, due to the work of both heterotrophic families involved in the model. In the following part, the perfect settling efficiency assumption was removed, and the volume of treated influent was increased in each cycle, testing the model under more real conditions. From the simulations performed, it was observed that an efficient settlement is needed to improve the concentration of microorganisms and increase the removal of nitrate and sulfate. In both this case and the previous one, in all simulations performed, even when COD is added, autotrophic denitrifiers remain the predominant microbial family in the reactor. Finally, a global sensitivity analysis was carried out to find out the parameters more affecting the process. All kinetic parameters involved in the model were first screened using the Morris method. From this initial analysis, it was evident that the removal of nitrogen compounds and the effluent sulfate concentration are mainly sensitive to parameters related to the hydrolysis of elemental sulfur into bioavailable sulfur and maximum growth rate of autotrophic denitrifiers. Then, a second analysis was carried out with machine learning systems, considering only the most sensitive kinetic parameters. The results confirmed those obtained with the previous method and showed that the decay constants of heterotrophic biomasses also turn out to be sensitive parameters. This last study will represent the major tool for the future experimental calibration and validation of the model