•Bio-refineries are an adequate framework to process organic waste materials.•Spent coffee grounds can be completely utilized in a bio-refinery to obtain high-value products.•A full set of high value ...products, biofuels and bioenergy can be obtained in a SCG bio-refinery.•Significant challenges still exist to develop and implement waste based bio-refineries.
Although normally seen as a problem, current policies and strategic plans concur that if adequately managed, waste can be a source of the most interesting and valuable products, among which metals, oils and fats, lignin, cellulose and hemicelluloses, tannins, antioxidants, caffeine, polyphenols, pigments, flavonoids, through recycling, compound recovery or energy valorization, following the waste hierarchy. Besides contributing to more sustainable and circular economies, those products also have high commercial value when compared to the ones obtained by currently used waste treatment methods. In this paper, it is shown how the bio-refinery framework can be used to obtain high value products from organic waste. With spent coffee grounds as a case study, a sequential process is used to obtain first the most valuable, and then other products, allowing proper valorization of residues and increased sustainability of the whole process. Challenges facing full development and implementation of waste based bio-refineries are highlighted.
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•P. tricornutum cultivated under natural conditions in Chile was characterized.•Real process data was used to scale-up the biorefinery scenarios.•Three P. tricornutum based ...biorefinery process configurations were proposed.•Integrated biorefinery for biofuels and high-value compounds revealed advantageous.
Microalgae are a rich source of proteins, carbohydrates and lipids, among other components, and thus, are considered to be the next generation biomass. However, in order to enhance the economic viability of its industrial production, all biomass components need to be valorized, requiring a multi-product biorefinery. Thus, this work proposes and conceptually analyses biorefinery processes for valorizing Phaeodactylum tricornutum for biofuels and high-value compounds, based on real data from a pilot-scale process. The algal biomass was biochemically characterized and the production was scaled-up to an industrial approach to analyze three biorefinery configurations, based on a 18 ton·year−1 of microalga biomass. The biomass revealed a composition of 7.85 wt% carbohydrates, 38.40 wt% proteins, 9.08 wt% lipids, 0.86 wt% fucoxanthin and 5.19 wt% biosilica. The biorefinery process addressed for biofuels production has an estimated annual production of 1.72, 0.35 and 1361 m3·year−1 of respectively biodiesel, bioethanol and biomethane. The biorefinery addressed for high-value compounds yields 0.18, 0.93 and 6.95 ton·year−1 of respectively fucoxanthin, biosilica and protein. The biorefinery designed for valorizing full microalgae biomass, showed to be more beneficial for promoting a circular economy. Biorefinery approach is useful for making sound and profitable decisions regarding microalgae bioproducts.
Sustainable production of renewable energy is being hotly debated globally since it is increasingly understood that first generation biofuels, primarily produced from food crops and mostly oil seeds ...are limited in their ability to achieve targets for biofuel production, climate change mitigation and economic growth. These concerns have increased the interest in developing second generation biofuels produced from non-food feedstocks such as microalgae, which potentially offer greatest opportunities in the longer term. This paper reviews the current status of microalgae use for biodiesel production, including their cultivation, harvesting, and processing. The microalgae species most used for biodiesel production are presented and their main advantages described in comparison with other available biodiesel feedstocks. The various aspects associated with the design of microalgae production units are described, giving an overview of the current state of development of algae cultivation systems (photo-bioreactors and open ponds). Other potential applications and products from microalgae are also presented such as for biological sequestration of CO
2, wastewater treatment, in human health, as food additive, and for aquaculture.
Abstract Many theories of cognitive aging are based on evidence that dopamine (DA) declines with age. Here we performed a systematic meta-analysis of cross-sectional PET and SPECT studies on the ...average effects of age on distinct DA targets (receptors, transporters, or relevant enzymes) in healthy adults (N=95 studies including 2,611 subjects). Results revealed significant moderate to large, negative effects of age on DA transporters and receptors. Age had a significantly larger effect on D1- than D2-like receptors. In contrast, there was no significant effect of age on DA synthesis capacity. The average age reductions across the DA system were 3.7–14.0% per decade. A meta-regression found only DA target as a significant moderator of the age effect. This study precisely quantifies prior claims of reduced DA functionality with age. It also identifies presynaptic mechanisms (spared synthesis capacity and reduced DA transporters) that may partially account for previously unexplained phenomena whereby older adults appear to use dopaminergic resources effectively. Recommendations for future studies including minimum required samples sizes are provided.
Nickel‐Catalyzed Cycloisomerization of 1,5‐Allenynes Nieto‐Carmona, Juan C.; Manjón‐Mata, Inés; Quirós, M. Teresa ...
Advanced synthesis & catalysis,
February 20, 2024, Letnik:
366, Številka:
4
Journal Article
Recenzirano
Odprti dostop
We report the Ni‐catalyzed cycloisomerization of 1,5‐allenynes. Substrates containing terminal alkynes afford cyclopentene derivatives, whereas internal alkynes lead to the formation of two ...consecutive C−C bonds to give fused 5–5 bicyclic compounds. The reaction shows a wide scope. Experimental and computational mechanistic studies suggest a Ni(0)−Ni(II) catalytic cycle. The reaction starts with an oxidative cyclometallation followed by a β‐hydrogen elimination. The trans arrangement of alkenyl and hydride ligands is key to allow formation of the second carbocycle.
A diastereoselective synthesis of borylated bicyclic 5‐5 fused ring systems by a domino Ni‐catalyzed hydroborylative polycyclization of allenynes has been developed. The reaction provides two new C−C ...and one C−B bonds and constitutes an atom‐economical method. It occurs rapidly, in absence of inert atmosphere, with an inexpensive Ni‐based catalyst and HBpin as boron source. The procedure showed excellent tolerance to functional groups and a wide scope. Derivatization of the borylated bicycles has been performed to explore the synthetic utility of the products. Experimental and DFT‐calculation results suggest that the process starts by an oxidative cyclometallation involving Ni(0) and both the allene and the alkyne moieties, followed by a stereoselective σ‐metathesis with HBpin. Formation of the second ring takes place through a non‐fully coplanar 1,2‐insertion into the Ni−H bond to give a nickelacyclohexene which finally evolves by reductive elimination.
An iron‐catalysed Kumada‐type cross‐coupling reaction between aryl substituted propargylic bromides and arylmagnesium reagents has been developed. Propargylic coupling products were the main or only ...outcome, and propargyl/allene regioselectivity was shown to depend on the electronic nature of the substituents on the triple bond of the substrate and on the arylmagnesium halide. Best selectivities were observed when electron donating substituents were present in either reagent. The process is stereoespecific, occurs with configuration inversion and no carbon‐based radicals seem to be involved in the mechanism.
Summary
The clinical significance of resistance/intolerance to hydroxycarbamide (HC) was assessed in a series of 890 patients with polycythaemia vera (PV). Resistance/intolerance to HC was recorded ...in 137 patients (15·4%), consisting of: need for phlebotomies (3·3%), uncontrolled myeloproliferation (1·6%), failure to reduce massive splenomegaly (0·8%), development of cytopenia at the lowest dose of HC to achieve a response (1·7%) and extra‐haematological toxicity (9%). With a median follow‐up of 4·6 years, 99 patients died, resulting in a median survival of 19 years. Fulfilling any of the resistance/intolerance criteria had no impact on survival but when the different criteria were individually assessed, an increased risk of death was observed in patients developing cytopenia Hazard ratio (HR): 3·5, 95% confidence interval (CI): 1·5–8·3, P = 0·003. Resistance/intolerance had no impact in the rate of thrombosis or bleeding. Risk of myelofibrotic transformation was significantly higher in those patients developing cytopenia (HR: 5·1, 95% CI: 1·9–13·7, P = 0·001) and massive splenomegaly (HR: 9·1, 95% CI: 2·3–35·9, P = 0·002). Cytopenia at the lowest dose required to achieve a response was also an independent risk factor for transformation to acute leukaemia (HR: 20·3, 95% CI: 5·4–76·5, P < 0·001). In conclusion, the unified definition of resistance/intolerance to HC delineates a heterogeneous group of PV patients, with those developing cytopenia being associated with an adverse outcome.
► Microalgae Scenedesmus obliquus (So) cultivated in a synthetic brewery effluent. ► Growth of So and reduction of COD, of total nitrogen and of total carbon. ► Influence of light/dark photoperiod, ...light intensity and culture aeration. ► Most adequate operating conditions for the So cultivation in this effluent.
This work analyses the potential of using microalgae Scenedesmus obliquus (So) for a brewery wastewater treatment and biomass production. The chemical oxygen demand (COD), total nitrogen (TN) and total carbon (TC) was followed in time, and the influence of light exposure, light intensity and culture aeration was studied. Results show that the most adequate conditions for cultivating So in this effluent are the aerated cultures, exposed to a 12h period of daily light, at 12000Lux intensity. At these conditions it is obtained a maximum of 0.9g of dry biomass per liter of culture, after 9days, for a maximum reduction of 57.5% and 20.8% of COD and TN, respectively, after 14days, and 56.9% of TC, after 13days, corresponding to the final values of 1692mg O2/L COD, 47mg N/L TN, and 1mg C/L TC.
A correct definition of the most adequate strategies and/or course of action to improve the sustainability of the wine industry must start with an evaluation, as objective and accurate as possible, ...of the sustainability performance of its products and processes. The main goal of this work is to perform a comparative sustainability evaluation of two Portuguese wines: a high market value “terroir” wine produced in small quantities, using grapes from a single vineyard, and a branded wine with lower market value, produced in large quantities using grapes from various regions. The evaluation follows a life cycle perspective and is based on seven sustainability indicators, selected taking into account the main issues pertinent to the wine industry. The functional unit is 0.75 L of wine produced that is the most common capacity of the wine bottles. The environmental and economic information used for the evaluation is mainly primary data obtained from the company, and complemented whenever necessary with secondary data from the literature or life cycle inventory databases. Results show that the main differences between the two wines are their water intensity and wastewater generated, being the values of the branded wine more than double those of the “terroir” wine, which is attributable to differences in the winemaking process, in particular the need to remove the SO2 added in the branded wine production. The calculated values for the carbon emissions are in good agreement with literature works. Some recommendations for improvement of the process sustainability are given.
•A comparative sustainability assessment of two Portuguese wines is performed.•Wines differ in terms of winemaking process, produced volume and market value.•System boundary includes winemaking, transportation of must and grapes, bottling and packaging.•Sustainability indicators use data mainly from real industrial practice.
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