Development of semi-theoretical light radiation and photosynthetic growth model for the optimal exploitation of wastewaters by microalgae

In the last decade, interest toward the potential application of microalgae has grown considering their potential use in industrial sectors as human nutrition and health, animal feed and biopolymers. Their ability to use light or/and organic carbon as energy source, makes them able to grow in a wide range of conditions. Because of that, the possibility to use alternative nutrients and water sources for their cultivation has been investigated. The microalgal cultivation using wastewaters mixed with synthetic medium might be a good combination that could reduce costs of water, nutrients and wastewater treatment. Anyway, wastewaters are frequently dark colored and contain toxic compounds that could have a negative impact on microalgal light uptake and metabolism. In this study, an experimental first principles hybrid method for the estimation of microalgal growth in non-transparent media was developed as a guide in the choice of the best formulation of wastewater-based culture media for microalgae. To carry out several experimental runs in parallel with different conditions (dilution of the wastewater, different light sources, etc.) a cylindrical bubble column PhotoBioReactor (PBR) was adopted. Its simple geometry allows the analysis of inside light fluxes. A non-metabolizable and non-toxic dye, in condition of purely light-radiative growth limitation, was added to the medium mimicking the reduced transparency of wastewaters. As final step to test the model, culture mediums with wastewater addiction were used for microalgal cultivation, showing their nutritive effects on growth

Conjugate Heat Transfer Numerical Study of the Ejector by Means of SU2 Solver

In this paper, the test supersonic ejector with conjugate heat transfer in solid bodies has been studied numerically. An extensive numerical campaign by means of open-source SU2 solver is performed to analyze the fluid dynamics of the ejector flowfield accounting for the heat conduction in solids. The fluid domain simulation is carried out by employing compressible RANS treatment whilst the heat distribution in solids is predicted by simultaneous solving the steady heat conduction equation. The working fluid is R245fa and all simulations are performed accounting for real gas properties of the refrigerant. Experimental data against numerical results comparison showed close agreement both in terms mass flow rates and static pressure distribution along the walls. Within the CFD trials, the most valuable flow parameters at a wall vicinity are compared: distribution across the boundary layer of the temperature and the turbulent kinetic energy specific dissipation rate, boundary layer displacement and momentum thicknesses. A comprehensive analysis of the simulation results cases with adiabatic walls against cases with heat permeable walls revealed the actual differences of the flow properties in the wall vicinity. However, the ejector performance has not changed noticeably while accounting for the heat conduction in solids. © 2021 Institute of Physics Publishing. All rights reserved

Correction: Whole-blood expression of inflammasome- and glucocorticoid-related mRNAs correctly separates treatment-resistant depressed patients from drug-free and responsive patients in the BIODEP study

We have corrected this Article post-publication, because Dr. Cattaneo’s affiliation details were originally incorrect (she was affiliated with three institutions but is in fact only linked to one: Biological Psychiatry Unit, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia). These changes reflect in both the PDF and HTML versions of this Article

Correction: Whole-blood expression of inflammasome- and glucocorticoid-related mRNAs correctly separates treatment-resistant depressed patients from drug-free and responsive patients in the BIODEP study.

We have corrected this Article post-publication, because Dr. Cattaneo's affiliation details were originally incorrect (she was affiliated with three institutions but is in fact only linked to one: Biological Psychiatry Unit, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia). These changes reflect in both the PDF and HTML versions of this Article

Whole-blood expression of inflammasome- and glucocorticoid-related mRNAs correctly separates treatment-resistant depressed patients from drug-free and responsive patients in the BIODEP study

Funder: DH | National Institute for Health Research (NIHR); doi: https://doi.org/10.13039/501100000272Abstract: The mRNA expression signatures associated with the ‘pro-inflammatory’ phenotype of depression, and the differential signatures associated with depression subtypes and the effects of antidepressants, are still unknown. We examined 130 depressed patients (58 treatment-resistant, 36 antidepressant-responsive and 36 currently untreated) and 40 healthy controls from the BIODEP study, and used whole-blood mRNA qPCR to measure the expression of 16 candidate mRNAs, some never measured before: interleukin (IL)-1-beta, IL-6, TNF-alpha, macrophage inhibiting factor (MIF), glucocorticoid receptor (GR), SGK1, FKBP5, the purinergic receptor P2RX7, CCL2, CXCL12, c-reactive protein (CRP), alpha-2-macroglobulin (A2M), acquaporin-4 (AQP4), ISG15, STAT1 and USP-18. All genes but AQP4, ISG15 and USP-18 were differentially regulated. Treatment-resistant and drug-free depressed patients had both increased inflammasome activation (higher P2RX7 and proinflammatory cytokines/chemokines mRNAs expression) and glucocorticoid resistance (lower GR and higher FKBP5 mRNAs expression), while responsive patients had an intermediate phenotype with, additionally, lower CXCL12. Most interestingly, using binomial logistics models we found that a signature of six mRNAs (P2RX7, IL-1-beta, IL-6, TNF-alpha, CXCL12 and GR) distinguished treatment-resistant from responsive patients, even after adjusting for other variables that were different between groups, such as a trait- and state-anxiety, history of childhood maltreatment and serum CRP. Future studies should replicate these findings in larger, longitudinal cohorts, and test whether this mRNA signature can identify patients that are more likely to respond to adjuvant strategies for treatment-resistant depression, including combinations with anti-inflammatory medications

Industrial bio-fractionation process of microalgae valuable products using supercritical {CO}2. A techno-economical evaluation

This work shows how Omega-3 triglycerides and carotenoids can be produced industrially from the microalga Chlorella vulgaris by fractionating extraction employing supercritical CO2, also estimating the relevant costs. One key point is that the devised process separates triglycerides from carotenoids. The estimates have been carried out by modelling both triglycerides and carotenoids extraction and purification, by quantifying the overall process material and heat balance and required operating conditions with the aid of a process simulation spreadsheet. The results showed separate streams of 138.3 kg per day of triglycerides and 8.4 kg per day of carotenoids can be obtained from a daily feed of 360 kg of freeze-dried microalga. In addition, an estimation of Operating Expense (OPEX) and Capital Expenditure (CAPEX) was carried out obtaining, respectively, 1050 k€/y and 3699 k€. The developed integrated process shows, in terms of costs and product quality, a significant improvement respect to previous works, underlying its feasibility for industrial applications

High-fat diet during adulthood interacts with prenatal stress, affecting both brain inflammatory and neuroendocrine markers in male rats

Prenatal stress (PNS) affects foetal programming and, through an interaction with subsequent challenges, can increase vulnerability to mood and metabolic disorders. We have previously shown that, following PNS, adult male rats are characterized by increased vulnerability to a metabolic stressor experienced at adulthood (8-week-high-fat diet—HFD). In this study, we specifically assessed whether PNS might interact with an adult metabolic challenge to induce an inflammatory phenotype. Changes in the expression levels of inflammatory (Il-1β, Tnf-α, Il-6) and of stress response mediators (Nr3c1, Fkbp5) as well as of mood and metabolic regulators (Bdnf, Ghs-R) were investigated in the hippocampus, prefrontal cortex and hypothalamus, brain regions involved in the pathogenesis of depression and prone to inflammation in response to stress. Overall, PNS reduced the expression of Bdnf and Tnf-α, while HFD administered at adulthood counteracted this effect suggesting that PNS impinges upon the same pathways regulating responses to a metabolic challenge at adulthood. Furthermore, HFD and PNS affected the expression of both Nr3c1 and Fkbp5, two neuroendocrine mediators involved in the response to stress, metabolic challenges and in the modulation of the emotional profile (as shown by the correlation between Fkbp5 and the time spent in the open arms of the elevated plus-maze). Overall, these results indicate that the same metabolic and neuroendocrine effectors engaged by PNS are affected by metabolic challenges at adulthood, providing some mechanistic insight into the well-known comorbidity between mood and metabolic disorders

An optimized separation process of microalgal lipidic products by molecular distillation: Techno-economic analysis

Microalgae are a sustainable rich source of high-added value metabolites, as omega-3 and carotenoids, for their ability to grow and accumulate these compounds also in wastewaters or in seawaters. Molecular distillation is a valid techinque respect to conventional distillation for fractionation of these thermosensitive products without affecting their nutritional and biological values. In this work a fractionation process using molecular distillation for separating fatty acids (in part omega-3) as esters and carotenoids from a microalgal lipidic extract, was designed and optimized. A Response Surface Method (RSM) analysis was carried out in order to find the optimal operative conditions of the molecular distiller in terms of temperature, pressure and purification ability. Furthermore, to complete the process scheme, also the design of the other equipments, including in particular the esterification reactor and the dewatering column, was done. In order to complete the feasibility study of the process, an estimation of the Operating Expense (OPEX) and Capital Expenditure (CAPEX), using the results of the simulations in terms of energy and utilities’ consumption, was done. All of these informations, both technical and economical, will be the basis for future industrial implementations of the designed process

Multi-component extraction process of high added value compounds from microalgae with supercritical CO2: A technical and economic study

In this work a multicomponent extraction process of high added value compounds (principally omega-3 fatty acids and carotenoids) from a microalgal matrix (Chlorella vulgaris), using supercritical CO2, was studied. Chlorella's metabolites were analyzed singularly, not as a pseudocomponent, and their affinities to the solvent were explored. The Simplified Broken and Intact Cell model was implemented in order to represent the extraction yields and to define the best conditions in terms of operative variables, ensuring the preservation of the bioactive and thermolabile properties of the extracted metabolites. Moreover, these conditions were chosen also for keeping carotenoids’ solubility in supercritical CO2 very low, in order to separate them (residue stream) from fatty acids (extract stream) without further purification steps. All of these informations were used to implement a simulation of the process, optimizing the daily cycles and increasing the productivity. As last step, calculations of the energy and utilities’ consumption for the estimation of the Operating Expense (OPEX) and Capital Expenditure (CAPEX), as starter point for a future industrial implementation of the process, were carried out