624 research outputs found

    MiR-205-5p inhibition by locked nucleic acids impairs metastatic potential of breast cancer cells

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    Mir-205 plays an important role in epithelial biogenesis and in mammary gland development but its role in cancer still remains controversial depending on the specific cellular context and target genes. We have previously reported that miR-205-5p is upregulated in breast cancer stem cells targeting ERBB pathway and leading to targeted therapy resistance. Here we show that miR-205-5p regulates tumorigenic properties of breast cancer cells, as well as epithelial to mesenchymal transition. Silencing this miRNA in breast cancer results in reduced tumor growth and metastatic spreading in mouse models. Moreover, we show that miR-205-5p knock-down can be obtained with the use of specific locked nucleic acids oligonucleotides in vivo suggesting a future potential use of this approach in therapy

    Multicolor Licklider Transmission Protocol: An LTP Version for Future Interplanetary Links

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    The Licklider Transport Protocol (LTP) is the "convergence layer" of choice in Interplanetary networks based on Delay-/Disruption-Tolerant architecture. It was designed for long-delay scheduled-intermittent links, offering either a reliable or an unreliable service, with "red" and "green" parts, respectively. The aim of this article is to present multicolor LTP, an LTP version consisting in a series of enhancements of which the most significant are the use of monochrome sessions, the introduction of an additional orange color offering a "notified" service, and the definition of default link colors. After a thorough examination of basic LTP mechanisms for all color variants, this article discusses two scenarios where orange seems particularly appealing: video streaming and optical interplanetary links. Numerical results offer further insight into the complex LTP mechanisms and also highlight the difference between LTP retransmissions and bundle protocol retransmissions, the latter benefitting from routing reprocessing. Multicolor LTP has already been implemented as an interplanetary overlay network (ION) plug-in and its enhancements have been proposed to Consultative Committee for Space Data Systems Space Internetworking Services Delay-/Disruption-Tolerant Networking working group for a possible inclusion in the next version of LTP specifications (LTPv2)

    Glyco-functionalized dinuclear rhenium(i) complexes for cell imaging

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    The design, synthesis and photophysical characterization of four new luminescent glycosylated luminophores based on dinuclear rhenium complexes, namely Glyco-Re, are described. The derivatives have the general formula [Re2(\u3bc-Cl)2(CO)6(\u3bc-pydz-R)] (R-pydz = functionalized 1,2-pyridazine), where a sugar residue (R) is covalently bound to the pyridazine ligand in the \u3b2 position. Different synthetic pathways have been investigated including the so-called neo-glycorandomization procedure, affording stereoselectively glyco-conjugates containing glucose and maltose in a \u3b2 anomeric configuration. A multivalent dinuclear rhenium glycodendron bearing three glucose units is also synthesized. All the Glyco-Re conjugates are comprehensively characterized and their photophysical properties and cellular internalization experiments on human cervical adenocarcinoma (HeLa) cells are reported. The results show that such Glyco-Re complexes display interesting bio-imaging properties, i.e. high cell permeability, organelle selectivity, low cytotoxicity and fast internalization. These findings make the presented Glyco-Re derivatives efficient phosphorescent probes suitable for cell imaging applicatio

    Amino grafted MCM-41 as highly efficient and reversible ecofriendly adsorbent material for the Direct Blue removal from wastewater

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    The very high adsorption efficiency of Direct Blue (DB), an anionic toxic azo dye, onto amino grafted mesoporous silica nanoparticles (MCM-41), was studied in this paper, for possible industrial applications. Interesting challenges and advances are proposed in this field, presenting an adsorbent able to efficiently and rapidly remove the anionic dye from water. The important added value of this work regards the system recycle, which allows both the DB and adsorbent material recover, with a global reduction of the environmental impact, in the viewpoint of the green economy. Indeed, this paper is the first example of very fast removal and recycle of great amounts of DB with adsorbent materials characterized by impressive adsorption/desorption capacities, at least of around 300mg/g for each adsorption cycle, potentially increasable by performing consecutive cycles of DB adsorption/desorption. In detail, the MCM-41 amino functionalization (MCM-41-NH2) was obtained after (MCM- 41-POST) and during (MCM-41-PRE) the synthesis of MCM-41, obtaining materials with different behavior towards the DB adsorption. The MCM-41-NH2 surface features and porous structure, before and after the dye adsorption, were carefully characterized. Considering the adsorption process, for investigating the nature of the DB/MCM-41-NH2 interaction, several parameters were studied: the contact time, the DB solutions pH values, adsorbent material and dye amount, with the additional analysis of how the adsorption process was influenced by the presence of electrolytes. The isotherms of adsorption were also considered. Although MCM-41-PRE exhibited a higher affinity towards DB molecules, the MCM-41-POST were able to rapidly desorb it, thus recycling both DB and the adsorbent material

    Antiproliferative, Ultrastructural, and Physiological Effects of Amiodarone on Promastigote and Amastigote Forms of Leishmania amazonensis

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    Amiodarone (AMIO), the most frequently antiarrhythmic drug used for the symptomatic treatment of chronic Chagas' disease patients with cardiac compromise, has recently been shown to have also specific activity against fungi, Trypanosoma cruzi and Leishmania. In this work, we characterized the effects of AMIO on proliferation, mitochondrial physiology, and ultrastructure of Leishmania amazonensis promastigotes and intracellular amastigotes. The IC50 values were 4.21 and 0.46 μM against promastigotes and intracellular amastigotes, respectively, indicating high selectivity for the clinically relevant stage. We also found that treatment with AMIO leads to a collapse of the mitochondrial membrane potential (ΔΨm) and to an increase in the production of reactive oxygen species, in a dose-dependent manner. Fluorescence microscopy of cells labeled with JC-1, a marker for mitochondrial energization, and transmission electron microscopy confirmed severe alterations of the mitochondrion, including intense swelling and modification of its membranes. Other ultrastructural alterations included (1) presence of numerous lipid-storage bodies, (2) presence of large autophagosomes containing part of the cytoplasm and membrane profiles, sometimes in close association with the mitochondrion and endoplasmic reticulum, and (3) alterations in the chromatin condensation and plasma membrane integrity. Taken together, our results indicate that AMIO is a potent inhibitor of L. amazonensis growth, acting through irreversible alterations in the mitochondrial structure and function, which lead to cell death by necrosis, apoptosis and/or autophagy

    Brazilian learners' understanding about Scientific Inquiry

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    There is agreement among researchers that one of the main objectives of scientific literacy is that all students understand Scientific Inquiry (SI). Even with many educational proposals guided by SI, there is still a difficulty to assess learners' notions about it. From this perspective, Lederman et al. (2014) published the VASI questionnaire, which evaluates the understanding of students from different countries about SI. The results presented in this paper represent the Brazilian sample. The objective was to evaluate the notions of scientific investigation of the elementary students from private and public schools. Analyzing the responses of students, it can be considered that they can conceptualize some aspects of the nature of scientific inquiry, but cannot identify them in real situations

    Solvent-Driven Supramolecular Wrapping of Self-Assembled Structures

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    Self‐assembly relies on the ability of smaller and discrete entities to spontaneously arrange into more organized systems by means of the structure‐encoded information. Herein, we show that the design of the media can play a role even more important than the chemical design. The media not only determines the self‐assembly pathway at a single‐component level, but in a very narrow solvent composition, a supramolecular homo‐aggregate can be non‐covalently wrapped by a second component that possesses a different crystal lattice. Such a process has been followed in real time by confocal microscopy thanks to the different emission colors of the aggregates formed by two isolated PtII complexes. This coating is reversible and controlled by the media composition. Single‐crystal X‐ray diffraction and molecular simulations based on coarse‐grained (CG) models allowed the understanding of the properties displayed by the different aggregates. Such findings could result in a new method to construct hierarchical supramolecular structures

    Solvent-Driven Supramolecular Wrapping of Self-Assembled Structures

    Get PDF
    Self-assembly relies on the ability of smaller and discrete entities to spontaneously arrange into more organized systems by means of the structure-encoded information. Herein, we show that the design of the media can play a role even more important than the chemical design. The media not only determines the self-assembly pathway at a single-component level, but in a very narrow solvent composition, a supramolecular homo-aggregate can be non-covalently wrapped by a second component that possesses a different crystal lattice. Such a process has been followed in real time by confocal microscopy thanks to the different emission colors of the aggregates formed by two isolated PtII complexes. This coating is reversible and controlled by the media composition. Single-crystal X-ray diffraction and molecular simulations based on coarse-grained (CG) models allowed the understanding of the properties displayed by the different aggregates. Such findings could result in a new method to construct hierarchical supramolecular structures
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