200 research outputs found
Understanding the Microfoundations of Entrepreneurial Ecosystems: Toward a Value-Based Method and Theory
Despite the progressmade by scholars, empirically investigating
entrepreneurial ecosystems (EEs) remains problematic
because of the inherent complexities and nonlinearities of interactions
among EE actors. The research to date has shown a tendency
to focus on macrolevel ecosystem dynamics while neglecting the
microfoundations of EEs. We contend that this negligence is due
to a lack of appropriate methodologies that can capture EE microfoundations
through a systemic value-based perspective. To fill this
gap, in this article,we propose a novelmethodological approach, the
value system method, which enables framing EEs through critical
causal interdependences between key actors’ business models that
foster value-exchange processes. Finally, the study provides a set of
research and policy implications for fostering the understanding of
EE microfoundations toward a value-based method and theory
Latanoprost ophthalmic solution in the treatment of open angle glaucoma or raised intraocular pressure: a review
Latanoprost is a prostaglandin F2-alpha isopropyl ester prodrug which is rapidly
hydrolyzed by esterases in the cornea to the biologically active latanoprost
acid. When latanoprost is topically administered into the eye, the cornea seems
to act like as a slow-release depot to the anterior segment. One hour after
administration maximum concentration is found in the iris, followed by the
anterior chamber and the ciliary body. Despite extensive research, controversy
remains about the real mechanism of action of this drug. Immunohistochemical
data have shown that the intraocular pressure (IOP) reduction with topical
prostaglandin F2-alpha is associated with a reduction of collagens within the
uveoscleral outflow pathway. Evidence from several experimental and clinical
studies suggests that latanoprost is a valuable addition first-line treatment
alternatives for glaucoma, ocular hypertension and even angle-closure glaucoma.
Strong points are its efficacy, which is demonstrated to be higher than that of
brimonidine, dorzolamide and timolol with fewer systemic adverse effects; a
convenient administration schedule; and the IOP-controlling pattern, which is
relatively flat compared with timolol and dorzolamide, and enables better
control in glaucoma progression, since large fluctuations may be associated with
the risk of developing glaucoma in untreated ocular hypertensive subjects
Cryotolerance of stallion spermatozoa relies on aquaglyceroporins rather than orthodox aquaporins
Aquaporins (AQPs), a family of ubiquitous water channels divided into orthodox AQPs, aquaglyceroporins (GLPs), and superAQPs, are present in stallion spermatozoa. The aim of this study was to elucidate the functional relevance of each group of AQPs during stallion sperm cryopreservation through the use of three different inhibitors: acetazolamide (AC), phloretin (PHL) and propanediol (PDO). Sperm quality and function parameters were evaluated in the presence or absence of each inhibitor in fresh and frozen-thawed samples. In the presence of AC, different parameters were altered (p < 0.05), but not in a concentration-or time-depending manner. PHL was found to decrease sperm motility, viability, acrosome integrity, and the percentages of spermatozoa with low membrane lipid disorder, high mitochondrial membrane potential (MMP) and high intracellular levels of calcium and superoxides (p < 0.05). Finally, the sperm motility, viability, acrosome integrity, the percentages of spermatozoa with low membrane lipid disorder, high MMP and high intracellular calcium levels were higher (p < 0.05) in PDO treatments than in the control. The sperm response to AC, PHL and PDO indicates that GLPs, rather than orthodox AQPs, play a crucial role during stallion sperm cryopreservation. Furthermore, post-thaw sperm quality was higher in PDO treatments than in the control, suggesting that this molecule is a potential permeable cryoprotectant
Towards 'Pt-free' Anion-Exchange Membrane Fuel Cells: Fe-Sn Carbon Nitride-Graphene 'Core-Shell' Electrocatalysts for the Oxygen Reduction Reaction
We report on the development of two new Pt-free electrocatalysts (ECs) for
the oxygen reduction reaction (ORR) based on graphene nanoplatelets (GNPs). We
designed the ECs with a core-shell morphology, where a GNP core support is
covered by a carbon nitride (CN) shell. The proposed ECs present ORR active
sites that are not associated to nanoparticles of metal/alloy/oxide, but are
instead based on Fe and Sn sub-nanometric clusters bound in coordination nests
formed by carbon and nitrogen ligands of the CN shell. The performance and
reaction mechanism of the ECs in the ORR are evaluated in an alkaline medium by
cyclic voltammetry with the thin-film rotating ring-disk approach and confirmed
by measurements on gas-diffusion electrodes. The proposed GNP-supported ECs
present an ORR overpotential of only ca. 70 mV higher with respect to a
conventional Pt/C reference EC including a XC-72R carbon black support. These
results make the reported ECs very promising for application in anion-exchange
membrane fuel cells. Moreover, our methodology provides an example of a general
synthesis protocol for the development of new Pt-free ECs for the ORR having
ample room for further performance improvement beyond the state of the art
I "media industry studies" in Italia: nuove prospettive sul passato e sul presente dell’industria cine-televisiva italiana
This issue investigates the current state and possible developments ofMedia Industry Studies in Italy. Through multiple perspectives andresearch methodologies, it offers insights on the changing role ofItalian public service broadcasting, on the network relations andmodes of production of Italian cinema in the 1950s and 1960s, and onthe challenges posed by the contemporary media landscape
HIV-1 Nef Induces Proinflammatory State in Macrophages through Its Acidic Cluster Domain: Involvement of TNF Alpha Receptor Associated Factor 2
Background: HIV-1 Nef is a virulence factor that plays multiple roles during HIV replication. Recently, it has been described that Nef intersects the CD40 signalling in macrophages, leading to modification in the pattern of secreted factors that appear able to recruit, activate and render T lymphocytes susceptible to HIV infection. The engagement of CD40 by CD40L induces the activation of different signalling cascades that require the recruitment of specific tumor necrosis factor receptor-associated factors (i.e. TRAFs). We hypothesized that TRAFs might be involved in the rapid activation of NF-kappa B, MAPKs and IRF-3 that were previously described in Nef-treated macrophages to induce the synthesis and secretion of proinflammatory cytokines, chemokines and IFN beta to activate STAT1, -2 and -3. Methodology/Principal Findings: Searching for possible TRAF binding sites on Nef, we found a TRAF2 consensus binding site in the AQEEEE sequence encompassing the conserved four-glutamate acidic cluster. Here we show that all the signalling effects we observed in Nef treated macrophages depend on the integrity of the acidic cluster. In addition, Nef was able to interact in vitro with TRAF2, but not TRAF6, and this interaction involved the acidic cluster. Finally silencing experiments in THP-1 monocytic cells indicate that both TRAF2 and, surprisingly, TRAF6 are required for the Nef-induced tyrosine phosphorylation of STAT1 and STAT2. Conclusions: Results reported here revealed TRAF2 as a new possible cellular interactor of Nef and highlighted that in monocytes/macrophages this viral protein is able to manipulate both the TRAF/NF-kappa B and TRAF/IRF-3 signalling axes, thereby inducing the synthesis of proinflammatory cytokines and chemokines as well as IFN beta
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Borexino : geo-neutrino measurement at Gran Sasso, Italy
Geo-neutrinos, electron anti-neutrinos produced in beta-decays of naturally occurring radioactive isotopes in the Earth, are a unique direct probe of our planet's interior. After a brief introduction of the geo-neutrinos' properties and of the main aims of their study, we discuss the features of a detector which has recently provided breakthrough achievements in the field, Borexino, a massive, calorimetric liquid scintillator detector installed at the underground Gran Sasso Laboratory. With its unprecedented radiopurity levels achieved in the core of the detection medium, it is the only experiment in operation able to study in real time solar neutrino interactions in the challenging sub-MeV energy region. Its superior technical properties allowed Borexino also to provide a clean detection of terrestrial neutrinos. Therefore, the description of the characteristics of the detected geo-neutrino signal and of the corresponding geological implications are the main core of the discussion contained in this work
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