37 research outputs found

    Utilization of centrate from wastewater treatment for the outdoor production of Nannochloropsis gaditana biomass at pilot-scale

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    In this work, the outdoor pilot-scale production of marine microalga Nannochloropsis gaditana using centrate from the anaerobic digestion of municipal wastewater was evaluated. For this, outdoor continuous cultures were performed in both tubular and raceways reactors mixing seawater with different centrate percentages (15%, 20% and 30%) as culture medium. It was demonstrated that N. gaditana can be produced using centrate as the only nutrients source but at percentages below 30%. At this level inhibition was caused by an excess of ammonium in both photobioreactors, as confirmed by chlorophyll fluorescence and average irradiance data, thus reducing productivity. At 15% and 20% centrate percentages, biomass productivity was equal to that measured when using Algal culture medium, of 0.48 and 0.10 g·l-1·day-1 for tubular and raceway reactors respectively. During the experiments nitrogen depuration decreased from 85% to 63% in tubular reactors with the increase of centrate percentage in culture medium and the decrease in biomass productivity, while in raceway reactors an opposite behavior was observed due to ammonia stripping from the cultures. Phosphorus depuration from the culture medium was 85% whatever the system used and the centrate percentage in culture medium indicating a phosphorus limitation into the cultures. By supplying additional phosphorus, to achieve an N:P ratio of 5, it was possible to enhance productivity and increase nitrogen depuration in both systems. The use of centrate is confirmed as a useful method for reducing microalgae production costs and for increasing process sustainability. Consequently, it is demonstrated that for the production of microalgae biomass, centrate from wastewater treatment plants can be used as the exclusive nutrient source, achieving high productivities and nutrient removal rates if using suitable strains and if the system is operated adequately

    A Reaction-Diffusion Numerical Model to Predict Cardiac Tissues Regeneration Via Stem Cell Therapy

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    Myocardial infarction is a leading cause of morbidity and mortality in the industrialized world. Extensive loss of cardiomyocytes, substituted by scarred tissue, is the key pathological mechanism leading to post infarc- tion heart failure [1]. The use of exogenous cells to replace lost cardiomy- ocytes has been demonstrated in animal models and in clinical trials by transplanting mesenchymal stem cells (MSCs) into the infarcted area. To optimize the initial conditions of the stem cell therapy, many experimen- tal studies are focused on determining the number and the localization of stem cells that must be implanted near the necrotic area. In this work we develop a quantitative numerical model able to simulate substrate con- centration profile, stem cells distribution and their proliferation near the ischemic area. The model describes the cell growth, the nutrient transport and its consumption through reaction-diffusion equations. The shrinking of the necrotic area leads in fact to a moving boundary problem. Some preliminary results, obtained in a 3D framework, are shown and discuss

    Learning models for classifying Raman spectra of genomic DNA from tumor subtypes

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    An early and accurate detection of different subtypes of tumors is crucial for an effective guidance to personalized therapy and in predicting the ability of tumor to metastasize. Here we exploit the Surface Enhanced Raman Scattering (SERS) platform, based on disordered silver coated silicon nanowires (Ag/SiNWs), to efficiently discriminate genomic DNA of different subtypes of melanoma and colon tumors. The diagnostic information is obtained by performing label free Raman maps of the dried drops of DNA solutions onto the Ag/NWs mat and leveraging the classification ability of learning models to reveal the specific and distinct physico-chemical interaction of tumor DNA molecules with the Ag/NW, here supposed to be partly caused by a different DNA methylation degree

    Learning models for classifying Raman spectra of genomic DNA from tumor subtypes

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    An early detection of different tumor subtypes is crucial for an effective guidance to personalized therapy. While much efforts focus on decoding the sequence of DNA basis to detect the genetic mutations related to cancer, it is becoming clear that physical properties, including structural conformation, stiffness, and shape, as well as biological processes, such as methylation, can be pivotal to recognize DNA modifications. Here we exploit the Surface Enhanced Raman Scattering (SERS) platform, based on disordered silver coated--silicon nanowires, to investigate genomic DNA from subtypes of melanoma and colon cancers and to efficiently discriminate tumor and healthy cells, as well as the different tumor subtypes. The diagnostic information is obtained by performing label--free Raman maps of the dried drops of DNA solutions onto the Ag/NWs mat, and leveraging the classification ability of learning models to reveal the specific and distinct interaction of healthy and tumor DNA molecules with nanowires

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

    A simplified process of swine slurry treatment by primary filtration and Haematococcus pluvialis culture to produce low cost astaxanthin

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    A simplified process for treating swine slurry through primary filtration and subsequent depuration of thefiltrate with the astaxanthin-rich microalga Haematococcus pluvialis is proposed. The first step comprisesa low-cost filtration system capable of reducing 66% of ammonia, 7% of phosphorus and 19% of chemicaloxygen demand, and increasing the concentration of nitrate, being this useful for subsequent growthof the algae. The second step comprises the discontinuous cultivation of H. pluvialis in diluted filteredslurry. The optimal dilution was researched by testing undiluted and 2, 4 and 8-fold diluted filtrate. Thisstep led to a drastic reduction in macro and micronutrients concentration (up to 99% for NO3-N andNH4-N, 98% for TP and 26% for chemical oxygen demand). After H. pluvialis growth the accumulation ofastaxanthin took place for 14 d in nutrient-deprived conditions: an astaxanthin accumulation of 1.27%on a dry weight basis was measured. These results indicate the possibility to couple low-cost filtrationand microalgae production to recover nutrients from swine wastewaters and to add value by producingvaluable astaxanthin for the feed market or for an on-farm utilization as feed addictive
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