944 research outputs found
NUT-charged black holes in matter-coupled N=2, D=4 gauged supergravity
Get PDFUsing the results of arXiv:0804.0009, where all timelike supersymmetric backgrounds of N=2, D=4 matter-coupled supergravity with Fayet-Iliopoulos gauging were classified, we construct genuine nut-charged BPS black holes in AdS_4 with nonconstant moduli. The calculations are exemplified for the SU(1,1)/U(1) model with prepotential F=-iX^0X^1. The resulting supersymmetric black holes have a hyperbolic horizon and carry two electric, two magnetic and one nut charge, which are however not all independent, but are given in terms of three free parameters. We find that turning on a nut charge lifts the flat directions in the effective black hole potential, such that the horizon values of the scalars are completely fixed by the charges. We also oxidize the solutions to eleven dimensions, and find that they generalize the geometry found in hep-th/0105250 corresponding to membranes wrapping holomorphic curves in a Calabi-Yau five-fold. Finally, a class of nut-charged Nernst branes is constructed as well, but these have curvature singularities at the horizon
Why Would the Rise of Social Media Increase the Influence of Traditional Media on Collective Judgments?
Get PDFIn our original article (Etter, Ravasi & Colleoni, 2018), we argued that the rise of social media is changing how evaluations are made public and impact the formation of organizational reputation. In their counterpoint, [authors] argue in favour of a separation between the construct of media reputation and social media reputation. They further argue that the rise of social media is actually strengthening the impact of traditional media on the evaluations of key stakeholders. Finally, they urge scholars to take a cautious approach to the assumption that social media are introducing more dynamism in the formation of (media) reputation. We agree that, in some circumstances, a conceptual distinction between (traditional) media reputation and social media reputation might be useful to advance future research and theorization of reputational dynamics. In fact, in our original article we highlighted the importance to acknowledge the potential existence of different and separate “reputational arenas” (Aula & Mantere, 2013; see also Bromberg & Fine, 2002). We are less persuaded, however, by the other objections that [authors] raise
Use of FBG sensors for monitoring cracks of the equestrian statue of Bartolomeo Colleoni in Venice
Get PDFThe Bartolomeo Colleoni monument suffered for years damage from the local climate. The process of restoring the Colleoni equestrian statue, started in 2003, allowed to understand how the bronze statue was originally cast and manufactured and the techniques used in its construction. During this process a relevant crack on the right foreleg was investigated in correspondence of the cast-on joining the right foreleg to the front portion of the horse body. The crack was investigated experimentally by Fiber Bragg Grating (FBG) sensors, avoiding any modelling because of the very complex structure of the statue. An array of FBG sensors connected in series was glued on the crack with the aim of capturing live information about the effect of applying stress on the crack opening. The monitoring system was successfully tested during repositioning of the RIDER on the horse and is available for long term inspection of the crack opening evolution
Purinergic receptor antagonist modulates hyperalgesia and allodynia in a mouse model of neuropathy : involvement of NO system at central and peripheral nervous system level
No full textNeuropathic pain, consequent to peripheral injury, has been associated with upregulation of NOS expression and subsequent NO overproduction at level of both injured sciatic nerve and
spinal cord. Animal models of nerve injury provide a reliable tool for investigating the
mechanisms underlying neuropathic pain. First aim of this work was to study NO and its associated biosynthetic enzymes, at different pain transmission anatomic steps, in mononeuropathy induced by chronic constriction injury of C57BL/65 mice sciatic nerve. The paw withdrawal latency and the sensitivity to tactile stimuli were evaluated at 3, 7 and 14 days after injury by the plantar test and the dynamic plantar aesthesiometer, respectively. At the
same times, thalamus, L4-L6 dorsal spinal cord, corresponding ipsilateral dorsal root ganglia (DRGs) and ipsilateral sciatic nerve, proximal to injury, were removed using a dissecting microscope. Neuronal and inducible nitric oxide synthase (i and nNOS) content was measured by western immunoblotting. Nitric oxide production was assessed on the basis of nitrite/nitrate,
which are the oxidation end products of nitric oxide, using a fluorimetric procedure.
Hyperalgesia and allodynia were already maximal at 3 days and they remained elevated up to 14 days. On 3rd day, the expression of iNOS was unmodified both locally and centrally and only at subsequent evaluation times increased in central and peripheral nervous system. In contrast, nNOS was precociously elevated in contralateral thalamus and only later it was upregulated in the peripheral nervous tissues. Nitric oxide content increased in all tissues,
except for contralateral thalamus, at 7 and 14th day. These results support the hypothesis that NO-NOS system is involved in neuropathic pain, particularly nNOS seems to have a role on its development and maintenance; instead iNOS in later phases. So it appears to be important marker of painful neuropathy both in the central and peripheral nervous system.
ATP activates cation ion channels, P2X receptors, and G-protein-coupled P2Y receptors and it is now recognised as an endogenous mediator of pain. The second objective was to evaluate the possible role of purinergic signalling in hyperalgesic and allodynic responses. Therefore we determined the effects of a non-selective P2 purinergic receptor-antagonist, pyridoxalphosphate-
6-azophenyl-2’,4’-disulfonic acid (PPADS), on pain behaviour and increase in NONOS
system. The administration in mice of PPADS (6.25, 12.5 and 25 mg/kg, i.p.), once a day
for eleven days, from day 3 after the nerve injury, dose and time dependently attenuated both mechanical allodynia and hyperalgesia. The complete antiallodynic and antihyperalgesic efficacy of PPADS 25 mg/kg was associated with 1) reduction in nNOS content of contralateral thalamus, DRGs and sciatic nerve, 2) decrease in overexpressed iNOS in all tissues and, consequently, 3) inhibition of NO overproduction. Finally, we can hypothesize that PPADS is therapeutically effective, because it binds the different subtypes of purinoceptors
(P2X and P2Y) involved in neuropathic pain
Vinylphosphonic acid/methacrylamide system as a durable intumescent flame retardant for cotton fabric
No full textA novel intumescent flame retardant treatment, consisting of vinylphosphonic acid (VPA) as the acid source and methacrylamide (MAA) as blowing agent, was designed and applied onto cotton fabrics. The grafting of reactive monomers onto cellulose chains was carried out using potassium persulfate as initiator of a radical polymerization technique. The thermal and fire behavior of the treated fabrics was thoroughly investigated: in particular, the VPA/MAA coating was able to exert a protective action, giving rise to the formation of a stable swollen char on the surface of textile fibers upon heating, hence improving the flame retardancy of cotton. In addition, the treated fabric achieved self-extinction as assessed by horizontal flame spread tests. Finally, a remarkable weight loss was observed only after the first washing cycle, then the samples did not show any significant weight loss, hence confirming the durability of the self-extinguishing treatment, even after five laundering cycles
Publisher correction: Spatio-temporal variability of processes across Antarctic ice-bed-ocean interfaces (vol 9, 2289, 2018)
No full textThe original version of this Article contained an error in the spelling of the author Florence Colleoni, which was incorrectly given as Florence Colloni. This has been corrected in both the PDF and HTML versions of the Article
Effect of hybrid phosphorus-doped silica thin films produced by sol-gel method on the thermal behavior of cotton fabrics
No full textThe aim of this work was to prepare hybrid organic-inorganic silica thin films to provide cotton fabrics with flame retardant properties and to investigate the films’ influence on the thermal and burning behavior of the treated samples. The fabrics were modified with three different sols in order to study the effect of pure silica sol-gel precursor, g-aminopropyltriethoxysilane (APTES), and that of the hybrid sols consisting of the APTES and the phosphorus compound diethylphosphite. Furthermore, in order to improve the cross-linking degree and the phosphorus-nitrogen synergistic effect on flame retardancy of the P-doped silica thin film the melamine-based resinwas added in the third sol. To evaluate the chemical structure of the coating material, pure xerogels of the treatment solutions were applied to glass slides and tested by ATR FT-IR spectroscopy. The cotton fabrics were impregnated with the sols by a padding-squeezing process and then dried. Thermal behavior of the treated cotton samples was investigated by thermogravimetric/differential scanning calorimetry analysis (TGA-DTG/DSC) and compared to the untreated one. The flame retardancy was tested according to the ASTM D 1230 standard method. The results showed a substantial enhancement of char-forming properties and flame retardancy for the fabrics modified with the thin films
Social Media and the Formation of Organizational Reputation
Get PDFThe rise of social media is changing how evaluative judgments about organizations are produced and disseminated in the public domain. In this article, we discuss how these changes question traditional assumptions that research on media reputation rests upon, and we offer an alternative framework that begins to account for how the more active role of audiences, the changing ways in which they express their evaluations, and the increasing heterogeneity and dynamism that characterizes media reputation influence the formation of organizational reputations
Electromagnetic field‐induced adaptive response in Schwann cells through DNA methylation, histone deacetylation, and oxidative stress
Get PDFSchwannomas are benign tumors of the peripheral nervous system arising from the transformation of Schwann cells (SCs). On the whole, these tumors are related to alterations of the neurofibromin type 2 gene, coding for the oncosuppressor merlin, a cytoskeleton-associated protein belonging to the ezrin-radixin-moesin family. However, the underlying mechanisms of schwannoma onset and progression are not fully elucidated, whereas one of the challenges might be the environment. In this light, the exposure to electromagnetic field (EMF), generated by the use of common electrical devices, has been defiantly suggested as the cause of SCs transformation even if the evidence was mostly epidemiologic. Indeed, insubstantial mechanisms have been so far identified to explain SCs oncotransformation. Recently, some in vitro evidence pointed out alterations in proliferation and migration abilities in SCs exposed to EMF (0.1 T, 50 Hz, 10 min). Here, we used the same experimental paradigma to discuss the involvement of putative epigenetic mechanisms in SCs adaptation to EMF and to explain the occurrence of hypoxic alterations after the exposure. Our findings indicate a set of environmental-induced changes in SCs, toward a less-physiological state, which may be pathologically relevant for the SCs differentiation and the schwannoma development
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