120 research outputs found

    Metal-Organic-Framework-based nanofiltration membranes for selective multi-cationic recovery from seawater and brines

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    Nanofiltration (NF) is gaining a role of increasing importance in Zero Liquid Discharge (ZLD)/Minimal Liquid Discharge (MLD) systems, enhancing the efficiency of downstream technologies to recover valuable minerals from seawater and brines. However, often the purity of the recovered minerals does not meet market specifications, making ZLD/MLD currently economically unfeasible. To such end, in this study, a novel positively charged NF membrane was developed to enhance magnesium and calcium selectivity. The membrane comprised: (i) an ultrafiltration substrate and (ii) an active layer that incorporated NH2-MIL-101(Al) and ZnO nanoparticles in a chitosan matrix. The influence of different loadings of NH2-MIL-101(Al) and ZnO on membrane structure, selectivity and water permeability was investigated. Initial filtration tests with single-salt solutions at 1000 ppm (NaCl, Na2SO4, MgCl2, CaCl2) showed that the membrane with 35%wt of ZnO presented the highest rejections of MgCl2 (90.10%) and CaCl2 (86.49%). Selectivity towards MgCl2 and CaCl2 was higher than those of commercial membranes (NF90 and NF270) and the positively charged membranes introduced in recent literature. The novel synthesized membrane in this work was also tested with synthetic seawater and brine at a trans-membrane pressure of 30 bar. Results highlighted the intriguing competitiveness of the novel membrane in terms of magnesium and calcium selectivity with NF90 and NF270 within the field of both seawater and brine valorization.The authors would like to acknowledge that parts of the research activities were carried out within the framework of "Programma Operativo Nazionale Ricerca e Innovazione2014-2020 (CCI 2014IT16M2OP005), Fondo Sociale Europeo, Azione I.1 “Dottorati Innovativi con caratterizzazione Industriale”, Code: DOT204NJ79, CUP: B73D20005110001. J. López research was developed under the Margarita Salas postdoctoral fellowship from Ministerio de Universidades (MIU) and founded by the European Union-NextGenerationEU. Moreover, J.L. Cortina received support for the research through the “ICREA Academia” recognition for excellence in research funded by the Generalitat de Catalunya.Peer ReviewedPostprint (published version

    Metal-Organic-Framework-based nanofiltration membranes for selective multi-cationic recovery from seawater and brines

    Get PDF
    Nanofiltration (NF) is gaining a role of increasing importance in Zero Liquid Discharge (ZLD)/Minimal Liquid Discharge (MLD) systems, enhancing the efficiency of downstream technologies to recover valuable minerals from seawater and brines. However, often the purity of the recovered minerals does not meet market specifications, making ZLD/MLD currently economically unfeasible. To such end, in this study, a novel positively charged NF membrane was developed to enhance magnesium and calcium selectivity. The membrane comprised: (i) an ultrafiltration substrate and (ii) an active layer that incorporated NH2-MIL-101(Al) and ZnO nanoparticles in a chitosan matrix. The influence of different loadings of NH2-MIL-101(Al) and ZnO on membrane structure, selectivity and water permeability was investigated. Initial filtration tests with single-salt solutions at 1000 ppm (NaCl, Na2SO4, MgCl2, CaCl2) showed that the membrane with 35%wt of ZnO presented the highest rejections of MgCl2 (90.10%) and CaCl2 (86.49%). Selectivity towards MgCl2 and CaCl2 was higher than those of commercial membranes (NF90 and NF270) and the positively charged membranes introduced in recent literature. The novel synthesized membrane in this work was also tested with synthetic seawater and brine at a trans-membrane pressure of 30 bar. Results highlighted the intriguing competitiveness of the novel membrane in terms of magnesium and calcium selectivity with NF90 and NF270 within the field of both seawater and brine valorization

    Flow cytometry based techniques to study testicular acidophilic granulocytes from the protandrous fish gilthead seabream (Sparus aurata L.)

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    The gilthead seabream is a protandrous seasonal breeding teleost that is an excellent model for studying the testicular regression process which occurs in both seasonal testicular involution and sex reversion. Little is known about the cell types and the molecular mechanisms involved in such processes, mainly because of the lack of appropriate methods for testis dissociation, and testicular cell isolation, culture and functional characterization. We have previously reported that gilthead seabream acidophilic granulocytes infiltrate the testis at post-spawning stage, settle close to the spermatogonia and accumulate intracellular interleukin-1ÎČ. In this paper, we report several flow cytometry based assays which allow to establish the role played by gilthead seabream testicular acidophilic granulocytes and permits their quantification

    Mosaicism for combined tetrasomy of chromosomes 8 and 18 in a dysmorphic child: A result of failed tetraploidy correction?

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    <p>Abstract</p> <p>Background</p> <p>Mosaic whole-chromosome tetrasomy has not previously been described as a cause of fetal malformations.</p> <p>Case presentation</p> <p>In a markedly dysmorphic child with heart malformations and developmental delay, CGH analysis of newborn blood DNA suggested a 50% dose increase of chromosomes 8 and 18, despite a normal standard karyotype investigation. Subsequent FISH analysis revealed leukocytes with four chromosomes 8 and four chromosomes 18. The child's phenotype had resemblance to both mosaic trisomy 8 and mosaic trisomy 18. The double tetrasomy was caused by mitotic malsegregation of all four chromatids of both chromosome pairs. A possible origin of such an error is incomplete correction of a tetraploid state resulting from failed cytokinesis or mitotic slippage during early embryonic development.</p> <p>Conclusion</p> <p>This unique case suggests that embryonic cells may have a mechanism for tetraploidy correction that involves mitotic pairing of homologous chromosomes.</p

    Feeding behaviour and digestion physiology in larval fish – current knowledge and gaps and bottlenecks in research

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    Food uptake follows rules defined by feeding behaviour that determines the kind and quantity of food ingested by fish larvae as well as how live prey and food particles are detected, captured and ingested. Feeding success depends on the progressive development of anatomical characteristics and physiological functions and on the availability of suitable food items throughout larval development. The fish larval stages present eco-morpho-physiological features very different from adults and differ from one species to another. The organoleptic properties, dimensions, detectability, movements characteristics and buoyancy of food items are all crucial features that should be considered, but is often ignored, in feeding regimes. Ontogenetic changes in digestive function lead to limitations in the ability to process certain feedstuffs. There is still a lack of knowledge about the digestion and absorption of various nutrients and about the ontogeny of basic physiological mechanisms in fish larvae, including how they are affected by genetic, dietary and environmental factors. The neural and hormonal regulation of the digestive process and of appetite is critical for optimizing digestion. These processes are still poorly described in fish larvae and attempts to develop optimal feeding regimes are often still on a ‘trial and error’ basis. A holistic understanding of feeding ecology and digestive functions is important for designing diets for fish larvae and the adaptation of rearing conditions to meet requirements for the best presentation of prey and microdiets, and their optimal ingestion, digestion and absorption. More research that targets gaps in our knowledge should advance larval rearing

    Overexpression of S100A4 in human cancer cell lines resistant to methotrexate

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    Methotrexate is a chemotherapeutic drug that is used in therapy of a wide variety of cancers. The efficiency of treatment with this drug is compromised by the appearance of resistance. Combination treatments of MTX with other drugs that could modulate the expression of genes involved in MTX resistance would be an adequate strategy to prevent the development of this resistance. Methods: The differential expression pattern between sensitive and MTX-resistant cells was determined by whole human genome microarrays and analyzed with the GeneSpring GX software package. A global comparison of all the studied cell lines was performed in order to find out differentially expressed genes in the majority of the MTX-resistant cells. S100A4 mRNA and protein levels were determined by RT-Real-Time PCR and Western blot, respectively. Functional validations of S100A4 were performed either by transfection of an expression vector for S100A4 or a siRNA against S100A4. Transfection of an expression vector encoding for ÎČ-catenin was used to inquire for the possible transcriptional regulation of S100A4 through the Wnt pathway. Results: S100A4 is overexpressed in five out of the seven MTX-resistant cell lines studied. Ectopic overexpression of this gene in HT29 sensitive cells augmented both the intracellular and extracellular S100A4 protein levels and caused desensitization toward MTX. siRNA against S100A4 decreased the levels of this protein and caused a chemosensitization in combined treatments with MTX. ÎČ-catenin overexpression experiments support a possible involvement of the Wnt signaling pathway in S100A4 transcriptional regulation in HT29 cells. Conclusions: S100A4 is overexpressed in many MTX-resistant cells. S100A4 overexpression decreases the sensitivity of HT29 colon cancer human cells to MTX, whereas its knockdown causes chemosensitization toward MTX. Both approaches highlight a role for S100A4 in MTX resistanc

    The role of the melatoninergic system in epilepsy and comorbid psychiatric disorders

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    Abstract There is emerging evidence of the beneficial role of the melatonin system in a wide range of psychiatric and neurologic disorders, including anxiety, depression, and epilepsy. Although melatoninergic drugs have chronobiotic and antioxidant properties that positively influence circadian rhythm desynchronization and neuroprotection in neurodegenerative disorders, studies examining the use of melatonin for epilepsy's comorbid psychiatric and neurological symptomatology are still limited. Preclinical and clinical findings on the beneficial effects of the melatonin system on anxiety, depression, and epilepsy suggest that melatoninergic compounds might be effective in treating comorbid behavioral complications in epilepsy beyond regulation of a disturbed sleep-wake cycle

    Structural insights into the catalysis and regulation of E3 ubiquitin ligases

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    Covalent attachment (conjugation) of one or more ubiquitin molecules to protein substrates governs numerous eukaryotic cellular processes, including apoptosis, cell division and immune responses. Ubiquitylation was originally associated with protein degradation, but it is now clear that ubiquitylation also mediates processes such as protein–protein interactions and cell signalling depending on the type of ubiquitin conjugation. Ubiquitin ligases (E3s) catalyse the final step of ubiquitin conjugation by transferring ubiquitin from ubiquitin-conjugating enzymes (E2s) to substrates. In humans, more than 600 E3s contribute to determining the fates of thousands of substrates; hence, E3s need to be tightly regulated to ensure accurate substrate ubiquitylation. Recent findings illustrate how E3s function on a structural level and how they coordinate with E2s and substrates to meticulously conjugate ubiquitin. Insights regarding the mechanisms of E3 regulation, including structural aspects of their autoinhibition and activation are also emerging

    Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

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    In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field
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