1,780 research outputs found

    Saharan dust deposition may affect phytoplankton growth in the mediterranean sea at ecological time scales

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    The surface waters of the Mediterranean Sea are extremely poor in the nutrients necessary for plankton growth. At the same time, the Mediterranean Sea borders with the largest and most active desert areas in the world and the atmosphere over the basin is subject to frequent injections of mineral dust particles. We describe statistical correlations between dust deposition over the Mediterranean Sea and surface chlorophyll concentrations at ecological time scales. Aerosol deposition of Saharan origin may explain 1 to 10% (average 5%) of seasonally detrended chlorophyll variability in the low nutrient-low chlorophyll Mediterranean. Most of the statistically significant correlations are positive with main effects in spring over the Eastern and Central Mediterranean, conforming to a view of dust events fueling needed nutrients to the planktonic community. Some areas show negative effects of dust deposition on chlorophyll, coinciding with regions under a large influence of aerosols from European origin. The influence of dust deposition on chlorophyll dynamics may become larger in future scenarios of increased aridity and shallowing of the mixed layerPostprint (published version

    Improving the Laser Texture Strategy to Get Superhydrophobic Aluminum Alloy Surfaces

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    Changing the wetting properties of surfaces is attracting great interest in many fields, in particular to achieve a surface with a superhydrophobic behavior. Laser machining is an emerging technique to functionalize materials with high precision and flexibility without any chemical treatment. However, when it is necessary to treat large area surfaces laser-based methods are still too slow to be exploited in industrial productions. In this work, we show that by improving the laser texture strategy it is possible to reduce the laser processing time to produce superhydrophobic aluminum alloy surfaces. Three different surface texture geometries were micromachined; namely, square, circular and triangular lattice grooves. We found that if the spacing between the grooves is narrow, i.e., when the percentage of the textured surface is high, the volume of air trapped inside the micromachined structures plays an important role in the wetting behavior. Meanwhile, when the groove spacing approaches the droplet dimensions, the texture geometry has a preponderant influence. Based on these findings an appropriate choice of the laser texture strategy allowed the fabrication of superhydrophobic aluminum alloy surfaces with a 10% reduction of processing time

    Advances in Viral Aquatic Animal Disease Knowledge: The Molecular Methods' Contribution

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    Viruses are pervasive components of aquatic ecosystems, and most of them are harmless to humans and animals; however, several aquatic viruses can infect animals, leading to diseases, especially when fish are confined, such as in aquaculture facilities. Traditional methods used to detect and study viruses have been widely applied to aquatic animals' viruses, leading to the successful isolation, identification and understanding of several of them. However, they have limits, which can be overcome by molecular methods, such as polymerase chain reaction (PCR)-based assays, sequencing and in situ hybridisation. A standard PCR, followed by the sequencing of purified amplicons, is an effective method for both identifying well-known viruses and discovering new ones. In situ hybridisation, in which a labelled probe binds to a nucleic acid sequence in tissue, is able to correlate the presence of viruses to lesions. Novel molecular isothermal methods, such as loop-mediated isothermal amplification (LAMP), were also developed and applied to viral aquatic animal diseases, bringing molecular diagnosis into the field. This review considers the scientific literature dealing with the molecular methods employed hitherto to study the most relevant finfish and shellfish viral pathogens, stressing their advantages and disadvantages. Aquaculture is the fastest-growing food-producing sector, with a global production of 122.6 million tonnes in 2020. Nonetheless, aquatic animal production can be hampered by the occurrence of viral diseases. Furthermore, intensive farming conditions and an increasing number of reared fish species have boosted the number of aquatic animals' pathogens that researchers have to deal with, requiring the quick development of new detection and study methods for novel unknown pathogens. In this respect, the molecular tools have significantly contributed to investigating thoroughly the structural constituents of fish viruses and providing efficient detection methods. For instance, next-generation sequencing has been crucial in reassignment to the correct taxonomic family, the sturgeon nucleo-cytoplasmic large DNA viruses, a group of viruses historically known, but mistakenly considered as iridoviruses. Further methods such as in situ hybridisation allowed objectifying the role played by the pathogen in the determinism of disease, as the cyprinid herpesvirus 2, ostreid herpesvirus 1 and betanodaviruses. Often, a combination of molecular techniques is crucial to understanding the viral role, especially when the virus is detected in a new aquatic animal species. With this paper, the authors would critically revise the scientific literature, dealing with the molecular techniques employed hitherto to study the most relevant finfish and shellfish viral pathogens

    Redspotted Grouper Nervous Necrosis Virus and the Reassortant RGNNV/SJNNV In Vitro Susceptibility against a Commercial Peroxy-Acid Biocide under Different Conditions of Use

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    Aquaculture is a constantly growing sector. The intensification of fish production and the movement of aquatic animals could cause the spread of infectious diseases. Remarkably, the diffusion of viral agents represents the major bottleneck for finfish production, and viral encephalopathy and retinopathy (VER) is considered the most impacting disease for Mediterranean aquaculture. No effective therapies are available to contrast VER, and vaccination can be applied only in grow-out facilities. Hence, programs to minimize the sanitary risks in farms are paramount to implementing hygienic standards and biosecurity. This study aimed to evaluate the in vitro virucidal activity of a peroxy-acid disinfectant (Virkon® S, DuPont, Sudbury, UK) towards the two NNV strains most widespread in the Mediterranean Sea. Remarkably, two protocols were applied to assess the virucidal activity under different conditions of use: the suspension test and the net test. The latter has been applied to evaluate the efficacy of the biocide on instruments, simulating the infield application. The obtained results demonstrated the suitability of the tested biocide for NNV inactivation, being effective under some of the tested conditions. However, the presence of organic matter, the concentration of the product, and the application conditions can significantly affect the result of the disinfection procedure

    Detection of Human and Fish Viruses in Marine Gastropods

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    Marine gastropods represent a major food source for higher trophic levels and an important source of animal protein for humans. Like bivalve molluscs, gastropods can accumulate several types of contaminants; however, the bioaccumulation of microorganisms, particularly viruses, has been poorly investigated in these animals. This study focused on gastropods (Tritia mutabilis, Bolinus brandaris and Rapana venosa) collected during the fishing season from 2017 to 2021 in the north-western Adriatic Sea, and on clams (Ruditapes philippinarum) harvested in the same geographical area, in order to evaluate the presence of human and fish viruses in their tissues. A virological investigation was carried out on the digestive gland using molecular methods. The presence of hepatitis A virus was detected in one sample, whereas noroviruses were not present in the investigated specimens. Regarding fish viruses, it was possible to detect the presence of nervous necrosis virus (NNV) in 26.5% of the analyzed gastropods; however, the histological examination did not show any pathological changes in the nervous tissue in both NNV-positive and -negative batches. As a whole, the investigated gastropods showed the ability to bioaccumulate viruses; however, lower contamination by human viruses compared to bivalve molluscs was pointed out, posing a minor concern to human health

    C2238/αANP modulates apolipoprotein E through Egr-1/miR199a in vascular smooth muscle cells in vitro

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    Subjects carrying the T2238C ANP gene variant have a higher risk to suffer a stroke or myocardial infarction. The mechanisms through which T2238C/αANP exerts detrimental vascular effects need to be fully clarified. In the present work we aimed at exploring the impact of C2238/αANP (mutant form) on atherosclerosis-related pathways. As a first step, an atherosclerosis gene expression macroarray analysis was performed in vascular smooth muscle cells (VSMCs) exposed to either T2238/αANP (wild type) or C2238/αANP. The major finding was that apolipoprotein E (ApoE) gene expression was significantly downregulated by C2238/αANP and it was upregulated by T2238/αANP. We subsequently found that C2238/αANP induces ApoE downregulation through type C natriuretic peptide receptor (NPR-C)-dependent mechanisms involving the upregulation of miR199a-3p and miR199a-5p and the downregulation of DNAJA4. In fact, NPR-C knockdown rescued ApoE level. Upregulation of miR199a by NPR-C was mediated by a reactive oxygen species-dependent increase of the early growth response protein-1 (Egr-1) transcription factor. In fact, Egr-1 knockdown abolished the impact of C2238/αANP on ApoE and miR199a. Of note, downregulation of ApoE by C2238/αANP was associated with a significant increase in inflammation, apoptosis and necrosis that was completely rescued by the exogenous administration of recombinant ApoE. In conclusion, our study dissected a novel mechanism of vascular damage exerted by C2238/αANP that is mediated by ApoE downregulation. We provide the first demonstration that C2238/αANP downregulates ApoE in VSMCs through NPR-C-dependent activation of Egr-1 and the consequent upregulation of miR199a. Restoring ApoE levels could represent a potential therapeutic strategy to counteract the harmful effects of C2238/αANP

    Multisensory Perception and Learning: Linking Pedagogy, Psychophysics, and Human–Computer Interaction

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    In this review, we discuss how specific sensory channels can mediate the learning of properties of the environment. In recent years, schools have increasingly been using multisensory technology for teaching. However, it still needs to be sufficiently grounded in neuroscientific and pedagogical evidence. Researchers have recently renewed understanding around the role of communication between sensory modalities during development. In the current review, we outline four principles that will aid technological development based on theoretical models of multisensory development and embodiment to foster in-depth, perceptual, and conceptual learning of mathematics. We also discuss how a multidisciplinary approach offers a unique contribution to development of new practical solutions for learning in school. Scientists, engineers, and pedagogical experts offer their interdisciplinary points of view on this topic. At the end of the review, we present our results, showing that one can use multiple sensory inputs and sensorimotor associations in multisensory technology to improve the discrimination of angles, but also possibly for educational purposes. Finally, we present an application, the ‘RobotAngle’ developed for primary (i.e., elementary) school children, which uses sounds and body movements to learn about angles

    Swim Bladder Disorders in Koi Carp (Cyprinus carpio)

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    Swim bladder disorders and consequent buoyancy problems are encountered in ornamental fish, including koi carp. Nevertheless, beyond clinical and pharmacologicalmanagement, they are largely underdiagnosed. In this study, nine koi carp showing abdominal swelling and abnormal swimming behavior were investigated. Clinical approach, varying from case to case, included ultrasonographic and X-ray investigations, bacteriological analysis of the collected fluid, antimicrobial susceptibility pattern, and possibly histological analysis. Diagnostic imaging, corroborating gross examination, documented swim bladder deformation/dislocation and serous fluid within the swim bladder chambers of most animals. Bacteria belonging to the Aeromonas hydrophila/caviae group and Shewanella xiamenensis were identified. S. xiamenensis strains showed a sensibility to all tested molecules except for one strain, which was resistant to tetracycline and cyprofloxacin. Antibiotic treatment succeeded in the full recovery of three cases in which S. xiamemensis infection was detected. Chronic aerocystitis was histologically documented where tissue was available. The swim bladder histopathological findings highlighted a chronic process that had compromised the quality of life of the animals. A multidisciplinary clinical\u2013pathological and microbiological approach is highly suggested to recognize swim bladder conditions as early as possible, aiming to drive medical intervention and raising the chances of fish survival

    Development and diagnostic validation of a one-step multiplex RT-PCR assay as a rapid method to detect and identify Nervous Necrosis Virus (NNV) and its variants circulating in the Mediterranean

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    Nervous Necrosis Virus (NNV) represents one of the most threatening pathogens for Mediterranean aquaculture. Several NNV strains are currently co-circulating in the Mediterranean Basin with a high prevalence of the RGNNV genotype and the RGNNV/SJNNV reassortant strain and a more limited diffusion of the SJNNV genotype and the SJNNV/RGNNV reassortant. In the present study, a one-step multiplex RT-PCR (mRT-PCR) assay was developed as an easy, cost-effective and rapid diagnostic technique to detect RGNNV and the reassortant RGNNV/SJNNV strain and to distinguish them from SJNNV and the reassortant SJNNV/RGNNV strain in a single RT-PCR reaction. A unique amplification profile was obtained for each genotype/reassortant enabling their rapid identification from cell culture lysates or directly from brain tissues of suspected fish. The method's detection limit varied between 10 2.3 and 10 3.4 TCID ml -1 depending on viral strains. No cross-reacitivty with viruses and bacteria frequently associated with gilthead seabream, European seabass and marine environment was observed. The mRT-PCR was shown to be an accurate, rapid and affordable method to support traditional diagnostic techniques in the diagnosis of VNN, being able to reduce considerably the time to identify the viral genotype or the involvement of reassortant strains
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