3,388 research outputs found

    FT-IR Investigation of Methoxy Substituted Benzenes Adsorbed on Solid Acid Catalysts

    Get PDF
    The nature of the interaction on two different catalysts (zeolite BEA and \u3b3-alumina) of some aromatic substrates, 1,2-methylendioxybenzene, 1,2-ethylendioxybenzene, and 1,2-dimethoxybenzene, have been investigated by FT-IR spectroscopy. FT-IR data suggest that the adsorption of 1,2-methylendioxybenzene occurs through oxygen atoms and the molecule maintains the original puckered conformation, whereas the planar structure due to the absence of a fused ring in the case of 1,2- dimethoxybenzene and the twisted conformation of 1,2-ethylendioxybenzene cause an orientation of the molecules parallel to the catalyst surface, with the benzene ring directly interacting to it. The puckered conformation of MDB leads the benzene ring to be electron-deficient, then deactivated toward alkylation, such as confirmed by the obtained catalytic results, which show that MDB is totally not reactive using the investigated heterogeneous catalysts, while in the traditional homogeneous system shows a reactivity comparable to the other considered substrates

    Late Evaluation of Silent Cerebral Ischemia Detected by Diffusion-Weighted MR Imaging after Filter-Protected Carotid Artery Stenting

    Get PDF
    BACKGROUND AND PURPOSE: Postoperative diffusion-weighted MR imaging (DWI) often discloses new lesions after carotid artery stent placement (CAS), most of them asymptomatic. Our aim was to investigate the fate of these silent ischemic lesions. MATERIALS AND METHODS: We prospectively studied 110 patients undergoing protected transfemoral CAS, 98 of whom underwent DWI before and after the intervention. Patients in whom DWI disclosed silent postoperative lesions also had delayed MR imaging. Preoperative, postoperative, and delayed scans were compared. RESULTS: Of the 92 patients without postoperative symptoms, DWI disclosed 33 new silent ischemic lesions in 14 patients (15.2%), 13 of whom (30 lesions) underwent delayed MR imaging after a mean follow-up of 6.2 months. In 8 of these 13 patients (61%), MR imaging disclosed 12 persistent lesions (12/30, 40%). The reversibility rate depended significantly on the location (cortical versus subcortical) and size (0–5 versus 5–10 mm) of the lesions ( P χ 2 test). CONCLUSIONS: Because many silent ischemic lesions seen on postoperative DWI after CAS reverse within months, the extent of permanent CAS-related cerebral damage may be overestimated

    Waveguiding and SERS simplified Raman spectroscopy on biological samples

    Get PDF
    Biomarkers detection at an ultra-low concentration in biofluids (blood, serum, saliva, etc.) is a key point for the early diagnosis success and the development of personalized therapies. However, it remains a challenge due to limiting factors like (i) the complexity of analyzed media, and (ii) the aspecificity detection and the poor sensitivity of the conventional methods. In addition, several applications require the integration of the primary sensors with other devices (microfluidic devices, capillaries, flasks, vials, etc.) where transducing the signal might be difficult, reducing performances and applicability. In the present work, we demonstrate a new class of optical biosensor we have developed integrating an optical waveguide (OWG) with specific plasmonic surfaces. Exploiting the plasmonic resonance, the devices give consistent results in surface enhanced Raman spectroscopy (SERS) for continuous and label-free detection of biological compounds. The OWG allows driving optical signals in the proximity of SERS surfaces (detection area) overcoming spatial constraints, in order to reach places previously optically inaccessible. A rutile prism couples the remote laser source to the OWG, while a Raman spectrometer collects the SERS far field scattering. The present biosensors were implemented by a simple fabrication process, which includes photolithography and nanofabrication. By using such devices, it was possible to detect cell metabolites like Phenylalanine (Phe), Adenosine 5-triphosphate sodium hydrate (ATP), Sodium Lactate, Human Interleukin 6 (IL6), and relate them to possible metabolic pathway variation

    Fabrication and Applications of Micro/Nanostructured Devices for Tissue Engineering

    Get PDF
    Nanotechnology allows the realization of new materials and devices with basic structural unit in the range of 1–100 nm and characterized by gaining control at the atomic, molecular, and supramolecular level. Reducing the dimensions of a material into the nanoscale range usually results in the change of its physiochemical properties such as reactivity, crystallinity, and solubility. This review treats the convergence of last research news at the interface of nanostructured biomaterials and tissue engineering for emerging biomedical technologies such as scaffolding and tissue regeneration. The present review is organized into three main sections. The introduction concerns an overview of the increasing utility of nanostructured materials in the field of tissue engineering. It elucidates how nanotechnology, by working in the submicron length scale, assures the realization of a biocompatible interface that is able to reproduce the physiological cell–matrix interaction. The second, more technical section, concerns the design and fabrication of biocompatible surface characterized by micro- and submicroscale features, using microfabrication, nanolithography, and miscellaneous nanolithographic techniques. In the last part, we review the ongoing tissue engineering application of nanostructured materials and scaffolds in different fields such as neurology, cardiology, orthopedics, and skin tissue regeneration

    Foreign Policy and the Ideology of Post-ideology: The Case of Matteo Renzi’s Partito Democratico

    Get PDF
    The post-communist Italian Left has experienced a long phase of ideational misalignment between ideas placed at different levels, as a qualified discursive institutionalist approach demonstrates. Background public philosophies have often clashed with post-communist political ideology, while foreign policy programmes have often contradicted specific policies. Under the leadership of Matteo Renzi, however, the PD is now experiencing a moment of remarkable ideational consistency. Rather than being founded on entirely new premises, this new consensus folds old elements into new ones and shows all the defining traits of post-ideology. Yet, by espousing post-ideology, Renzi is making an ultimately ideological move whose limitations may soon start to show

    Laboratory injection molder for the fabrication of polymeric porous poly-epsilon-caprolactone scaffolds for preliminary mesenchymal stem cells tissue engineering applications

    Get PDF
    This study presents a simple and rapid fabrication technique involving injection molding and particle leaching (IM/PL) to fabricate the porous scaffold for tissue engineering applications. Sodium Chloride (NaCl) and Sucrose are separately mixed with the poly-epsilon-caprolactone (PCL) granules using a screwed thermo-regulated extruder, then the biocompatible scaffolds are fabricated through injection molding. The micro/nano-structure of the samples and their different grade of porosity were characterized by scanning electron microscopy and mercury intrusion porosimetry. Bone marrow-derived mesenchymal stem cells are chosen for cell culture and Hoechst 33342 staining was used to verify the biocompatibility of the polymeric porous surfaces. We concluded that, by using the same fast solvent free injection/leaching process, the use of Sucrose as porogen, instead of NaCl, allowed the obtainment of biocompatible scaffolds with a higher grade of porosity with suitable cell adhesion capacity for tissue engineering purpose

    National protest agenda and the dimensionality of party politics: Evidence from four East-Central European democracies

    Get PDF
    Contemporary democracies show considerable differences in the issue composition of their protest politics, which tends to remain relatively stable over time. In countries like Germany or the Czech Republic, the vast majority of protests have been mobilised around sociocultural issues, such as human rights, peace, nuclear power or the environment, and only a tiny portion of protest has focused on economic issues. At the opposite extreme, protest in France or Poland usually has a strongly economic character and voices demands relating to material redistribution and social policy. What lies behind the cross-country differences in national protest agendas? In this article, the national protest agenda depends on what issues mainstream political parties are contesting: the content and strength of the master-issue dimension. In reference to the literature on the multidimensional political space and niche political parties, one should expect that there is a substitutive effect; where the stronger a specific master-issue dimension is in party politics, the less salient that issue dimension is in protest politics. This substitutive effect results from the tendency of electoral politics to reduce political conflict to a single-dimension equilibrium, which decreases the importance of other issues and relegates the contest over secondary, niche issues to the realm of policy-seeking strategies, with protest being a common type of this political strategy. In party systems where single-dimension equilibrium does not exist and the master-issue dimension is weaker, the same dynamics result in a more convergent relationship between party and protest politics and a greater similarity between the protest- and party-system agendas. To investigate this theory, the national protest agendas in four countries are examined. The Czech Republic, Hungary, Poland and Slovakia show four combinations of two crucial factors that are not available in the old Western democracies: the content and the strength of the master-issue dimension. The study draws on an original dataset of protest events organised in the four countries between 1993 and 2010, and on qualitative and quantitative data on issue dimensions of party politics obtained from studies on party politics and expert surveys. The results show that in the Czech Republic, where the master-issue dimension has remained strongly economic, protest has been predominantly sociocultural. In Poland between 1993 and 2001 and Hungary between 1993 and 2006, the master-issue dimensions are strongly sociocultural, while protest is predominantly economic. There is no single-dimension equilibrium in party politics in Slovakia or in post-2001 Poland and mainstream parties compete on both economic and sociocultural issues. Consequently, the substitutive dynamics between party and protest politics is weaker and the issue agendas in party and protest arenas are here more alike. <br/

    A Cryogenic Underground Observatory for Rare Events: Cuore, an Update

    Get PDF
    CUORE is a proposed tightly packed array of 1000 TeO_{2} bolometers, each being a cube 5 cm on a side with a mass of 750 gms. The array consists of 25 vertical towers, arranged in a square, of 5 towers by 5 towers, each containing 10 layers of 4 crystals. The design of the detector is optimized for ultralow- background searches for neutrinoless double beta decay of ^{130}Te (33.8% abundance), cold dark matter, solar axions, and rare nuclear decays. A preliminary experiment involving 20 crystals of various sizes (MIBETA) has been completed, and a single CUORE tower is being constructed as a smaller scale experiment called CUORICINO. The expected performance and sensitivity, based on Monte Carlo simulations and extrapolations of present results, are reported.Comment: in press: Nucl. Phys. of Russian Academy of Sc
    • …
    corecore