1,721,000 research outputs found
Thermodynamics of (nano)interfaces
No full textThe chapter is a tutorial on the description of nanosystems by classical interfacial thermodynamics. After synthetically recalling the necessary basics, it shows by working examples of increasing complexity that several properties of inorganic, biological, and hybrid nano-objects are not stand-alone weird subjects but rather aspects of colloid and interface energetics. Touched topics include melting temperature and solubility of nanocrystals, phase rule for highly curved interfaces, superhydrophobic surfaces, and biomolecular machines
Thermodynamics of mechanical transduction of surface confined receptor/ligand reactions
No full textChemomechanics of surface stress is discussed in terms of interfacial thermodynamics. In the first section the paper shows how to quantitatively describe the chemical equilibrium of a receptor/ligand binding reaction confined at a solid-liquid interface and how the overall work of the reaction splits into chemical and surface work, that appears as a surface pressure. In the second section this thermodynamic model is applied to describe the experimental results of microcantilever bending induced by DNA hybridization occurring onto one of its face
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Biogenic supported lipid bilayers as a tool to investigate nano-bio interfaces
Get PDFHypothesis: Extracellular Vesicles (EVs) are natural nanosized lipid vesicles involved in most intercellular communication pathways. Given their nature, they represent natural cell membrane models, with intermediate complexity between real and synthetic lipid membranes. Here we compare EVs-derived (EVSLB) and synthetic Supported Lipid Bilayers (SLBs) in the interaction with cationic superparamagnetic iron oxide nanoparticles (SPIONs). The aim is twofold: (i) exploit SPIONs as nanometric probes to investigate the features of EVSLBs as novel biogenic platforms; (ii) contribute at improving the knowledge on the behavior of SPIONs with biological interfaces. Experiments: Quartz Crystal Microbalance, X-ray Reflectivity, Grazing-incidence Small-angle X-ray Scattering, Atomic Force Microscopy, Confocal Microscopy data on SPIONs-EVSLB were systematically compared to those on SPIONs challenging synthetic SLBs, taken as references. Findings: The ensemble of experimental results highlights the much stronger interaction of SPIONs with EVSLBs with respect to synthetic SLBs. This evidence strongly supports the hypotheses on the peculiar structure of EVSLBs, with cushioned non-flat areas and extended exposed surface; in addition, it suggests that these features are relevant in the response of biogenic membranes to nano-objects. These findings contribute to the fundamental knowledge on EVSLBs, key for their development both as biomimetic membranes, or as platforms for biomedical applications
Canine and Feline Mammary Tumours: In-vitro Study of the Autocrine Effect of Extracellular Vesicles Isolated by Ultracentrifugation and Size Exclusion Chromatography
No full textIntroduction: Extracellular vesicles (EVs) are membrane-bound vesicles produced by cells that play a key role in intercellular communication. This study aimed to evaluate the autocrine effect of canine and feline mammary tumour-derived EVs, comparing two different EV isolation methods.
Materials and Methods: EVs were isolated from canine (CIPp) and feline (FMCp) mammary tumour cell lines by ultracentrifugation and by size exclusion chromatography (SEC). A wound healing assay, a transwell migration/invasion assay and a proliferation assay were performed on CIPp and FMCp treated with CIPp- and FMCp-derived EVs, respectively. EVs isolated by ultracentrifugation and by SEC were compared for purity using the COlorimetric NANoplasmonic (CONAN) assay and the BCA protein assay.
Results: CIPp treated with CIPp EVs and FMCp treated with FMCp EVs showed a higher migration (P <0.0001) in the wound healing assay with no differences between ultracentrifugation and SEC. EVs purified by SEC induced a higher proliferation rate (P <0.05) in both cell lines when compared with EVs isolated by ultracentrifugation. CONAN assay confirmed a higher EV purity of SEC fractions. BCA assay showed a higher protein content in the EV pellet obtained by ultracentrifugation when compared with EVs purified by SEC.
Discussion: An autocrine effect of canine and feline mammary cancer-derived EVs on cell migration and proliferation was demonstrated. The effect of EVs isolated by ultracentrifugation might be enhanced by the co-presence of soluble proteins, while the functionality of EVs purified by SEC might be increased by their better preservation, which needs to be further investigated
The nanostructured secretome
Get PDFThe term secretome, which traditionally strictly refers to single proteins, should be expanded to also include the great variety of nanoparticles secreted by cells (secNPs) into the extracellular space, which ranges from high-density lipoproteins of a few nanometers to extracellular vesicles and fat globules of hundreds of nanometers. Widening the definition is urged by the ever-increasing understanding of the role of secNPs as regulators/mediators of key physiological and pathological processes, which also puts them in the running as breakthrough cell-free therapeutics and diagnostics. "Made by cells for cells", secNPs are envisioned as a sweeping paradigm shift in nanomedicine, promising to overcome the limitations of synthetic nanoparticles by unsurpassed circulation and targeting abilities, precision and sustainability. From a longer/wider perspective, advanced manipulation would possibly make secNPs available as building blocks for future "biogenic" nanotechnology. However, the current knowledge is fragmented and sectorial (the majority of the studies being focused on a specific biological and/or medical aspect of a given secNP class or subclass), the understanding of the nanoscale and interfacial properties is limited and the development of bioprocesses and regulatory initiatives is in the early days. We believe that new multidisciplinary competencies and synergistic efforts need to be attracted and augmented to move forward. This review will contribute to the effort by attempting for the first time to rationally gather and elaborate secNPs and their traits into a unique concise framework - from biogenesis to colloidal properties, engineering and clinical translation - disclosing the overall view and easing comparative analysis and future exploitation
- …
