1,326 research outputs found

    DEVELOPMENT OF A NOVEL SUNPHOTOMETER FOR AEROSOL AND DUST CHARACTERIZATION IN THE ATMOSPHERE

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    The term aerosol refers to a suspension of solid particles or liquid droplets in a gaseous medium. During the last decades, aerosols and the need to measure them have become increasingly important. Aerosols can affect human health, because large loads of aerosols degrade air quality. Aerosols generated by volcanic eruptions can be a danger to aviation and impose diversion of air routes, resulting in economic damage. Finally, aerosols are the most uncertain cause of global climate change because their properties vary greatly in time and space. In this work we propose a novel ground-based sunphotometer to measure aerosols. It\u2019s name is ARBOL (ARray of BOLometers). ARBOL is more flexible than common sunphotometers. The mechanical structure, the electronic layout and the acquisition software allow a better temporal resolution. In addition, six different wavelengths are measured simultaneously in the visible and near-infrared ranges. The thesis describes in detail the design, structure and implementation of each ARBOL component. Furthermore, instrumental characterizations and calibration are discussed. Finally, a first ARBOL has been installed at the Agency for the Protection of the Environment (ARPA, 583 a.s.l.) of Valle d\u2019Aosta, while a second at the astronomical observatory of Saint Barthelemy (OAVdA) (1700 a.s.l.). The two measurement sites are located a few km apart from each other, but at different altitudes. Comparison of simultaneous measurements from the two sites allows information to be retrieved on the lowest atmospheric layer and its aerosol content. Consequently, the results of a test campaign are also discussed in this work

    The GiSAS study: Rationale and design of pragmatic randomized controlled trial on aripiprazole, olanzapine and haloperidol in the long-term treatment of schizophrenia

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    Given the controversy about the comparative efficacy of first- compared with second-generation antipsychotics in the treatment of schizophrenia, more large-scale evidence is needed to guide clinicians in their prescriptions. Most randomized controlled trials (RCTs) were conducted in centers of excellence on highly selected samples, poorly representative of real-world patients, and often suffered conflicts of interest as they were sponsored by drug companies. The primary aim of the present study is to compare the effectiveness of haloperidol, olanzapine and aripiprazole in a representative sample of schizophrenia patients. The GiSAS trial is an open-label, independent, pragmatic RCT in Italian community-based public psychiatric services. At least 260 patients meeting the DSM-IV criteria for schizophrenia will be randomly allocated to one of the study drugs and followed up for one year. A two-year observational phase will follow. The primary outcome for tolerability will be the onset of metabolic syndrome. The primary endpoint for effectiveness will be discontinuation of antipsychotic monotherapy. Secondary measures include global functioning, time to discontinuation due to side-effects, change of lipid profile, extrapyramidal symptoms and other adverse effects. In the last four years, the GiSAS study group has been working to implement this multicenter RCT. The trial mechanism is now fully functional and working. As of end of February 2011, 260 subjects were randomized by 54 study investigators in 33 out of 43 participating centers

    Validation of a graphic test to quantitatively assess the dominant hand dexterity

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    Dexterity dysfunction is a key feature of disability in many neurological and non-neurological diseases. The Nine-Hole Peg Test (NHPT) is the most used test to assess hand dexterity in clinical practice but presents limitations. A new graphic test to enhance objective evaluation of the of the dominant hand dexterity is proposed. The task consists in drawing a continuous line in paths composed by a part with multiple orthogonal changes of direction (‘meander’), and a second part derived from the Archimedean spiral (‘spiral’). The test was validated in 200 healthy controls and 93 neurological patients. 48 patients performed also the NHPT. Several parameters were analyzed, among which total time, total length, number of touches and number of crossings. Healthy subjects display statistically significant differences with respect to pathological subjects in the case of total time, number of touches, and number of crossings (p<0.001), but not in the case of total length (p = 0.27) needed to complete the second sheet. Moreover, healthy controls display a learning effect, the time needed to complete the second sheet was significantly lower than for the first sheet (p<0.001), and an inverse correlation with age was observed (r = 0.56, p<0.001). The comparison between the NHPT and the new test showed a strong positive correlation (r = 0.71, p<0.001) whereas touches and crossing a weak positive one (r = 0.35, p = 0.01). The new test distinguishes between a slow but precise performance and a fast but imprecise performance, thus providing additional information with respect to NHPT

    In Vivo Isolation and Characterization of Stem Cells with Diverse Phenotypes Using Growth Factor Impregnated Biomatrices

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    BACKGROUND: The stimulation to differentiate into specific cell types for somatic stem cells is largely due to a series of internal and external signals coming from the microenvironment that surrounds the stem cell. Even though intensive research has been made, the basic mechanisms of plasticity and/or the molecules regulating stem cells proliferation and differentiation are not completely determined. Potential answers concerning the problems could be derived from the studies of stem cells in culture. METHODOLOGY/PRINCIPLE FINDINGS: We combine a new procedure (using the matrigel biopolymer supplemented with a selected cytokine/growth factor) with classic techniques such as light, confocal and electron microscopy, immunohistochemistry and cell culture, to perform an analysis on stem cells involved in the leech (Hirudo medicinalis) repair tissues. The leech has a relative anatomical simplicity and is a reliable model for studying a variety of basic events, such as tissue repair, which has a striking similarity with vertebrate responses. Our data demonstrate that the injection of an appropriate combination of the matrigel biopolymer supplemented with a selected cytokine/growth factor in the leech Hirudo medicinalis is a remarkably effective tool for isolating a specific cell population in vivo. A comparative analysis of biopolymer in vivo sorted stem cells indicates that VEGF recruited cells of a hematopoietic/endothelial phenotype whereas MCP-1/CCL2 isolated cells that were of an early myeloid lineage. CONCLUSION: Our paper describes, for the first time, a method allowing not only the isolation of a specific cell population in relation to the cytokine utilized but also the possibility to culture a precise cell type whose isolation is otherwise quite difficult. This approach could be broadly applied to isolate stem cells of diverse origins based on the recruitment stimuli employed

    Ras activation in Hirudo medicinalis angiogenic process

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    In some leeches like Hirudo medicinalis, any kind of stimulation (surgical wound or growth factor injection) provokes the botryoidal tissue response. This peculiar tissue, localized in the loose connective tissue between gut and body wall, is formed by granular botryoidal cells and flattened endothelial-like cells. Under stimulation, the botryoidal tissue changes its shape to form new capillaries. In mammals, the molecular regulation of the angiogenic phenotype requires coordinated input from a number of signalling molecules: among them the GTPase Ras is one of the major actor. In our current study, we determine whether Ras activation alone would be sufficient to drive vessels formation from leech botryoidal tissue. Our findings indicate that assembly and disassembly of actin filaments regulated by Ras protein is involved in morphological modification of botryoidal tissue cells during leech angiogenic process

    Hirudo medicinalis as alternative model for in vivo and in vitro studies on nanomaterials toxicity.

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    Due to the steady increase of production and use of engineered nanomaterials (NMs), intentional or unintentional discharges into the environment may occur. Since it is critical to develop new methods to fully understand NMs bioaccumulation and cytotoxicity, a reliable model in which analyze NMs effects both in vivo and in vitro is more than ever necessary. Here we propose the leech, Hirudo medicinalis, as alternative animal model to study multi-walled carbon nanotubes (MWCNTs) effects by means of an extended study that includes in vivo and in vitro treatments. First, MWCNTs were dispersed in leeches\u2019 water to mimic a possible environmental exposure. In a second assay, a MWCNTs-supplemented biomatrix was injected in leeches\u2019 body wall. Thirdly, leeches macrophages were isolated and cultured to analyze their responses after MWCNTs in vitro treatment. Our results show that water dispersed MWCNTs evoke in the leech body wall a strong inflammatory response, involving mainly monocyte-macrophages cells. Ultrastructural analysis of MWCNTs-supplemented biomatrix revealed that in leech macrophages MWCNTs are internalized both in an active (phagocytosis) and a passive manner (membrane piercing). Finally, MWCNTs in vitro treatment cause the decrease of cell proliferation rate and the increase of ROS production and of the apoptotic rate. Our combined experimental approaches, not only attest the ability of MWCNTs in inducing a potent inflammatory response, but also confirm Hirudo medicinalis as a good alternative model that can be successfully used to study, both in vivo and in vitro, the possible harmful effects of any nanomaterial

    Further studies on the gangliosidic nature of the cholinergic-specific antigen, Chol-1.

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    The antigen designated as Chol-1 beta, detected by an antiserum specific for cholinergic neurons, has been purified to homogeneity from ganglioside mixtures extracted from Torpedo electric organ and pig brain. The final products from the two sources behaved identically in a wide range of tests and gave coincident immunopositive and Ehrlich-positive spots after thin layer chromatography in seven different solvent systems; they were thus considered to be identical and to constitute a single, pure chemical species. Gas-chromatographic analysis revealed the presence of long-chain bases, glucose, galactose, N-acetylgalactosamine, and sialic acid in integral molar ratios of 1:1:2:1:3; the compound's reactivity to cholera toxin after Vibrio cholerae sialidase treatment on thin layer chromatography and the recovery of GM1 as sole product of exhaustive sialidase treatment identified it as a member of the gangliotetrahexosyl series. From the products of partial enzymatic desialylation and treatment with beta-galactosidase and a comparison of the compound's immunoreactivity to anti-Chol-1 antisera with that of other trisialogangliosides of defined molecular structure, we were able to assign a disialosyl residue alpha-Neu5Ac-(2----8)-alpha-Neu5Ac-(2----3)- to the inner galactose, and we suggest GalNAc as a possible site of linkage of the third sialic acid

    A hedgehog-like signal is involved in slow muscle differentation in Sepia officinalis (Mollusca)

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    In the tentacle of Sepia officinalis, smooth-like, helical and cross-striated fibres deriving from different populations of myoblasts are present. Myoblasts appear at different times during the development and express two muscle-specific transcription factors: Myf5-like and MyoD-like factors. Myoblasts expressing Myf5 give rise to slow fibres, whereas fast fibres derive from MyoD+ myoblasts. We found that a Hedgehog (Hh)-like signal was present in the central nerve cord of the tentacle from the early stages of development and in a specific population of myoblasts which are the precursors of slow muscle fibres. The model showed interesting similarities with vertebrates, in which Sonic hedgehog is a protein secreted by axial structures (the notochord and neurotube) and is involved in slow muscle differentiation and in survival of muscle precursors

    Insights Into the Immune Response of the Black Soldier Fly Larvae to Bacteria

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    In insects, a complex and effective immune system that can be rapidly activated by a plethora of stimuli has evolved. Although the main cellular and humoral mechanisms and their activation pathways are highly conserved across insects, the timing and the ef\ufb01cacy of triggered immune responses can differ among different species. In this scenario, an insect deserving particular attention is the black soldier \ufb02 y (BSF), Hermetia illucens (Diptera: Stratiomyidae). Indeed, BSF larvae can be reared on a wide range of decaying organic substrates and, thanks to their high protein and lipid content, they represent a valuable source of macromolecules useful for different applications (e.g., production of feedstuff, bioplastics, and biodiesel), thus contributing to the development of circular economy supply chains for waste valorization. However, decaying substrates bring the larvae into contact with different potential pathogens that can challenge their health status and growth. Although these life strategies have presumably contributed to shape the evolution of a sophisticated and ef \ufb01 cient immune system in this dipteran, knowledge about its functional features is still fragmentary. In the present study, we investigated the processes underpinning the immune response to bacteria in H. illucens larvae and characterized their reaction times. Our data demonstrate that the cellular and humoral responses in this insect show different kinetics: phagocytosis and encapsulation are rapidly triggered after the immune challenge, while the humoral components intervene later. Moreover, although both Gram-positive and Gram-negative bacteria are completely removed from the insect body within a few hours after injection, Gram-positive bacteria persist in the hemolymph longer than do Gram-negative bacteria. Finally, the activity of two key actors of the humoral response, i.e., lysozyme and phenoloxidase, show unusual dynamics as compared to other insects. This study represents the \ufb01 rst detailed characterization of the immune response to bacteria of H. illucens larvae, expanding knowledge on the defense mechanisms of this insect among Diptera. This information is a prerequisite to manipulating the larval immune response by nutritional and environmental factors to increase resistance to pathogens and optimize health status during mass rearing
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