403 research outputs found

    Green synthesis of vanillin: Pervaporation and dialysis for process intensification in a membrane reactor

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    In the present work, two different membrane processes (pervaporation and dialysis) are compared in view of their utilization in a membrane reactor, where vanillin, which is probably the most important aroma of the food industry, is synthesized in a green and sustainable way. The utilized precursor (ferulic acid, which is possibly a natural product from agricultural wastes) is partially oxidized (photocatalytically or biologically) and the product is continuously recovered from the reacting solution by the membrane process to avoid its degradation. It is observed that pervaporation is much more selective towards vanillin than dialysis, but the permeate flux of dialysis is much higher. Furthermore, dialysis can work also at lower temperatures and can be used to continuously restore the consumed substrate into the reacting mixture. A mathematical model of the integrated process (reaction combined with membrane separation) reproduces quite satisfactorily the experimental results and can be used for the analysis and the design of the process

    Sequential biological and photocatalysis based treatments for shipboard slop purification: A pilot plant investigation

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    This study investigated the treatment of a shipboard slop containing commercial gasoline in a pilot plant scale consisting of a membrane biological reactor (MBR) and photocatalytic reactor (PCR) acting in series. The MBR contributed for approximately 70% to the overall slop purification. More precisely, the biological process was able to remove approximately 40%, on average, of the organic pollution in the slop. Nevertheless, the membrane was capable to retain a large amount of organic molecules within the system, amounting for a further 30% of the influent total organic content removal. However, this affected the membrane fouling, thus resulting in the increase of the pore blocking mechanism that accounted for approximately 20% to the total resistance to filtration (2.85∙10 13 m −1 ), even if a significant restoration of the original membrane permeability was obtained after chemical cleanings. On the other hand, the biological treatment produced a clear solution for the photocatalytic system, thereby optimizing the light penetration and generation of highly oxidizing active oxygen species that enabled the degradation of bio-recalcitrant compounds. Indeed, low total organic carbon (TOC) values (<10 mg L −1 ) were achieved in the output of the photocatalytic reactor by means of only 60 Einstein (E) of cumulative impinging energy after the addition of K 2 S 2 O 8 . Overall, coupling the two processes enabled very high TOC removal (ca. 95%)

    Copper deficiency-associated myelopathy in cryptogenic hyperzincemia: A case report

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    Copper deficiency syndrome is an underestimated cause of posterior myelitis. We describe the case of a 41-year-old woman, who developed a subacute ataxic paraparesis associated with low back pain. Her 3T spine MRI showed a thin hyperintense FS-Echo T2 longitudinally extensive lesion involving the posterior columns of the cervical cord (from C2 to C6). An extensive diagnostic work-up excluded other causes of myelopathy and blood tests pointed out hypocupremia and mild hyperzincemia. Patients affected by this rare form of oligoelement deficiency typically develop progressive posterior column dysfunction with sensory ataxia and spasticity, sometimes associated with sensori-motor polyneuropathy. Clinical and radiological characteristics of posterior myelopathy due to copper deficiency are briefly reviewed. Physicians should be aware of this condition since a prompt introduction of copper supplementation can avoid progression of the neurological damage. (www.actabiomedica.it)

    Alcohol-Selective Oxidation in Water under Mild Conditions via a Novel Approach to Hybrid Composite Photocatalysts

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    The oxidation of alcohols to carbonyl compounds in a clean fashion (i.e., with water as a solvent or under solvent-free conditions, and using O2 or H2O2 as the primary oxidant) is the subject of considerable research efforts. A new approach for the selective oxidation of soluble aromatic alcohols in water under mild conditions via a novel composite photocatalyst has been developed. The catalyst is synthesized by grafting 4-(4-(4-hydroxyphenylimino)cyclohexa-2,5dienylideneamino)phenol and silver nanoparticles onto the surface of moderately crystalline titanium dioxide. The titanium dioxide-based composite was first extensively characterized and then employed in the catalytic oxidation of 4-methoxybenzyl alcohol to 4-methoxybenzaldehyde under UV irradiation in water at room temperature. The corresponding aldehyde was obtained with unprecedented high selectivity (up to 86 %). The method is general and opens the route to fabrication of photocatalytic composites based on titanium dioxide functionalized with shuttle organic molecules and metal nanoparticles for a variety of oxidative conversions

    Pen shell Pinna nobilis L. (Mollusca: Bivalvia) from different peculiar environments: adaptive mechanisms of osmoregulation and neurotransmission

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    The pen shell Pinna nobilis (Linnaeus, 1758) is the largest endemic bivalve mollusc of the Mediterranean Sea, listed as an endangered species in the European Union. Because no information is available about the adaptation of pen shells to different habitats, herein the fundamental conditions of adaptation of P. nobilis to peculiar natural environments, such as the Strait of Messina (SM) and the meromictic Faro Lake (FL; Sicily, Italy), were explored by assessing the morphology, mucous production, osmoregulation and neurotransmission of their gills. Although gills of the pen shells from both sites exhibited a regular morphology, a higher presence of acid mucous cells was detected in P. nobilis from FL than SM, as well as higher levels of osmolytes but without interfering the osmoregulatory processes. About the functioning of gills, the cholinergic (i.e. acetylcholine and AChE) neuronal system was unaltered between individuals from the two sites, whereas the GABAergic neurotransmission (i.e. 4-aminobutyrate or GABA) was significantly augmented in gills of P. nobilis from FL than SM. This may be an adaptive response to hypoxic conditions in FL, as supported by the increased hypoxia-inducible factor (HIF-1α) in gills of pen shells from FL than SM. Noteworthy, this study reports for the first time the presence of the GABA neurotransmitter within the metabolite profile, obtained by application of a protonic Nuclear Magnetic Resonance (1H NMR)-based metabolomics approach, of a marine bivalve. Therefore, GABA may be suggested as a metabolite biomarker in pen shells. Overall, findings from this study provide new insights on the behavioural and adaptive responses of the pen shell Pinna nobilis settled in different peculiar environments

    Comparative study of haematology of two teleost fish (Mugil cephalus and Carassius auratus) from different environments and feeding habits

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    Haematological parameters are valuable indicators of fish health status. This study is aimed to provide baseline data of the blood profile of two teleost fish species living in different environments and with divergent feeding behaviour, namely the flathead grey mullet Mugil cephalus Linnaeus, 1758, a marine herbivorous fish, and the goldfish Carassius auratus (Linnaeus, 1758), a freshwater omnivorous fish. Using an automated system coupled with flow cytometry and light microscopy, significant variations were found between M. cephalus and C. auratus blood parameters, except for haemoglobin concentration (Hgb). A significant increase in red blood cell count (RBC) and haematocrit (Hct) levels, associated with reduced mean corpuscular volume (MCV), was revealed in mullets in respect to goldfish. These data may be attributable to differences in fish species, or to their divergent physiological activeness as high RBC values are associated with fast movement and high activity with streamlined bodies, or to environmental factors such as water salinity, an increase in which may lead to erythropoiesis as an adaptive process in seawater fish. Additionally, lower values of white blood cell count (WBC) and thrombocyte count (TC) were recorded in mullets with respect to goldfish, and these changes may be due to divergent feeding habits of the two fish species, or to their different environments since increased salinity may inversely affect WBC. Overall, findings from this study provide a better understanding of the influences of divergent environmental conditions and feeding habits on fish blood parameters. The combined use of an automatic haematological count with flow cytometry was demonstrated to be effective for an early assessment of blood parameters in different fish species

    A synthetic derivative of antimicrobial peptide holothuroidin 2 from mediterranean sea cucumber (Holothuria tubulosa) in the control of Listeria monocytogenes

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    Due to the limited number of available antibiotics, antimicrobial peptides (AMPs) are considered antimicrobial candidates to fight difficult-to-treat infections such as those associated with biofilms. Marine environments are precious sources of AMPs, as shown by the recent discovery of antibiofilm properties of Holothuroidin 2 (H2), an AMP produced by the Mediterranean sea cucumber Holothuria tubulosa. In this study, we considered the properties of a new H2 derivative, named H2d, and we tested it against seven strains of the dangerous foodborne pathogen Listeria monocytogenes. This peptide was more active than H2 in inhibiting the growth of planktonic L. monocytogenes and was able to interfere with biofilm formation at sub-minimum inhibitory concentrations (MICs). Atomic-level molecular dynamics (MD) simulations revealed insights related to the enhanced inhibitory activity of H2d, showing that the peptide is characterized by a more defined tertiary structure with respect to its ancestor. This allows the peptide to better exhibit an amphipathic character, which is an essential requirement for the interaction with cell membranes, similarly to other AMPs. Altogether, these results support the potential use of our synthetic peptide, H2d, as a template for the development of novel AMP-based drugs able to fight foodborne that are resistant to conventional antibiotics

    Haemolytic activity and characterization of nematocyst venom from Pelagia noctiluca (Cnidaria: Scyphozoa)

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    We investigated the haemolytic capacity of the crude venom extracted from isolated nematocysts of Pelagia noctiluca (Cnidaria: Scyphozoa), and evidenced the proteic fractions responsible for this activity. The nematocyst venom was used at various concentrations to evaluate the haemolytic activity and the lysosomal membrane stability of red blood cells of two teleostean species treated with the extract. The nematocyst extract was assayed against erythrocytes of the two teleostean species living in different environments, Carassius auratus as a common freshwater species, and Liza aurata as a representative of seawater species. Experiments on the haemolytic activity of P. noctiluca in the presence of lipid components of erythrocyte membranes showed that sphyngomyelin strongly inhibited this activity. The crude venom was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis SDS-PAGE and high performance liquid chromatography (HPLC) to detect the proteic composition, and it was found that the active haemolytic components of this venom are distributed in at least four protein fractions. The results of our experiments indicated that Pelagia noctiluca venom induces haemolysis and lysosomal membrane destabilisation in both species and that Carassius auratus was more susceptible to jellyfish venom than was Liza aurata. No significant differences in glutathione (GSH) levels were observed between control and treatments; consequently the toxins do not cause the oxidative stress but likely recognize specific targets (i.e. sphyngomyelin) in the plasmatic membrane of red blood cells

    Visible Light Induced Oxidation of Trans-ferulic Acid by TiO2 Photocatalysis

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    The oxidation of trans-ferulic acid (C 10H 10O 4) in aqueous TiO 2 dispersion occurs via the formation of a charge-transfer complex on the TiO 2 surface that is able to absorb visible light (\u3bb 65 400 nm). The main product is CO 2, whereas secondary oxidation products are organic species such as vanillin, caffeic acid, homovanillic acid, and vanillylmandelic acid. Oxidation through the formation of a charge-transfer complex occurs only in the presence of specific TiO 2 samples. Experiments in the absence of oxygen, in the presence of bromate ions and by using a phosphate-modified TiO 2, have been carried out for investigating the reaction mechanism. In order to study the interaction between trans-ferulic acid and TiO 2 surface and to characterize the charge-transfer complex, UV-Vis diffuse reflectance and FT-IR spectroscopies have been used. FT-IR characterization of TiO 2 samples in contact with the aqueous trans-ferulic acid solution indicates that the charge-transfer complex formation occurs via adsorption of bidentate ferulate species

    Effects of pesticides on Chelon labrosus (Risso, 1827) evaluated by enzymatic activities along the north eastern Sicilian coastlines (Italy)

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    Pesticides are frequently applied to agricultural activities to improve harvest, in terms of yield and product quality. Useful tools for ecotoxicological studies of marine ecosystems are based on biomarker application on bioindicator key fish species. The main aim of the present study was to detect the potential presence of pesticides in a polluted coastal marine environment, namely Milazzo Gulf, situated in the north eastern coast of Sicily (Italy), by measuring the enzymatic activities of the ecotoxicological biomarkers acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in brain and blood samples of Chelon labrosus. Also, Marinello Reserve was selected as a reference site. The data showed a significant inhibition in AChE (81%) and BChE (71%) activities in fish from Milazzo Gulf in respect to those from the reference site. The esterase inhibition is primarily due to the presence of organophosphorus insecticides and carbamates that resulted, in Milazzo Gulf, higher in concentration in respect to the reference quality standard decree (D.M. 260, 2010). The results obtained in this study confirm the suspected presence of insecticides in waters and fish from Milazzo Gulf, which may lead to a considerable hazard to humans. This study confirms the relevant advantages of the biomarker approach on fish species in the ecotoxicological evaluation of marine environments
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