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81.
Dylan J. Boday Beatrice Muriithi Robert J. Stover Douglas A. Loy 《Journal of Non》2012,358(12-13):1575-1580
Strong, electrically conducting aerogels were prepared by introducing polyaniline nanofibers to a silica sol just prior to gelation and drying through supercritical carbon dioxide processing. The addition of a few milligrams of polyaniline per cm3 increased the flexural strength of the cylindrical monoliths by 200%. Using preformed polymeric nanofibers avoided filling of microporosity often observed with polymer reinforcement of aerogels and allowed preparation of polyaniline–silica composite aerogels with surface areas over 900 m2/g. Despite the small amount of polyaniline nanofibers (1.3–16.5 wt.%), the composite aerogels were electrically conducting (8.0 × 10? 8–1.83 × 10? 5 S/cm) and it was possible to prepare chemiresistor sensors for detection of acidic (HCl) and basic (ammonia) gaseous molecules with response times similar to thin film sensors containing orders of magnitude more polyaniline. 相似文献
82.
Laurine R. ZuppVeronica L. Campanella DiAndra M. RudzinskiFrançois Beland Ronny Priefer 《Tetrahedron letters》2012,53(39):5343-5346
Microwave irradiation is a popular method in organic synthesis to achieve high yields in shorter reaction times. This decreases total ‘man-hours’ in a synthetic setting. Another technique used in organic chemistry to decrease manual manipulations, is solid support reagents. The benefits of this approach is that upon completion of a reaction, a simple filtration can be performed which expedites the work-up and also produces less organic waste. Friedel-Crafts alkylation has been explored using microwave chemistry as well as with solid-supported reagents. In comparison with traditional heating, as well as with AlCl3, superior yields were observed with silica-gel bound aluminum chloride (Si-AlClx) when microwave irradiated for only 5 min. 相似文献
83.
A new instrumental setup, which is based on the oscillatory squeezing flow model, was developed to characterize the viscoelastic
properties of foods and biopolymers. Analysis of the data was performed by two different approaches. The first approach employed
principles of vibration to determine viscous damping and elasticity of the sample harmonically compressed between two plates.
The second approach involved the use of additional calculations based on the squeezing flow model which were linked to concepts
of vibration analysis, such as mechanical impedance, to determine fundamental rheological parameters like complex viscosity
and related (elastic and viscous) moduli. The experimental setup for the method is simple to use and could be attached to
existing commercial instruments such as texture analyzers and universal testing machines. The use of the proposed method with
this type of instruments would provide them with the additional capability of performing dynamic rheological testing. The
dynamic mass of the instrument was significantly low when compared to that of other instruments that use similar principles.
This low dynamic mass enabled the use of relatively higher frequencies for the testing of the samples. Comparison of the viscous
and elastic moduli obtained with the proposed method and from conventional rheometers for a variety of foods and biopolymers
showed good agreements. 相似文献
84.
M. Beatrice Margaret R. Sankar S. Kalainathan R. Jayavel T. Irusan 《Crystal Research and Technology》2006,41(7):712-717
Tri Glycinsulphate with partial substitution of phosphoric acid, namely Tri Glycine Sulpho Phosphate (TGSP) has been grown by slow cooling method. Habit modifications have been observed with change in the concentration of ortho phosphoric acid (H3PO4). Monoclinic structure of the grown crystals has been confirmed using X‐ray diffraction analysis. TGSP crystals doped with L – Asparagine were also grown. The doping effect is qualitatively estimated using FTIR analysis. TGA, DTA studies and dielectric measurements were carried out for pure and L‐Asparagine doped TGSP crystals to investigate the thermal and electrical properties of the crystals. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
85.
Rosa Sparaco Ewa Kdzierska Agnieszka A. Kaczor Anna Bielenica Elisa Magli Beatrice Severino Angela Corvino Ewa Gibua-Tarowska Jolanta H. Kotliska Giorgia Andreozzi Paolo Luciano Elisa Perissutti Francesco Frecentese Marcello Casertano Anna Leniak Magdalena Bujalska-Zadrony Magorzata Ozibo Raffaele Capasso Vincenzo Santagada Giuseppe Caliendo Ferdinando Fiorino 《Molecules (Basel, Switzerland)》2022,27(19)
A new series of 5-norbornene-2-carboxamide derivatives was prepared and their affinities to the 5-HT1A, 5-HT2A, and 5-HT2C receptors were evaluated and compared to a previously synthesized series of derivatives characterized by exo-N-hydroxy-5-norbornene-2,3-dicarboximidenucleus, in order to identify selective ligands for the above-mentioned subtype receptors. Arylpiperazines represents one of the most important classes of 5-HT1AR ligands, and recent research concerning new derivatives has been focused on the modification of one or more portions of such pharmacophore. The combination of structural elements (heterocyclic nucleus, propyl chain and 4-substituted piperazine), known to be critical to the affinity to 5-HT1A receptors, and the proper selection of substituents led to compounds with high specificity and affinity towards serotoninergic receptors. The most active compounds were selected for further in vivo assays to determine their functional activity. Finally, to rationalize the obtained results, molecular docking studies were performed. The results of the pharmacological studies showed that Norbo-4 and Norbo-18 were the most active and promising derivatives for the serotonin receptor considered in this study. 相似文献
86.
Francesca Cicogna Emilia Bramanti Beatrice Campanella Stefano Caporali Luca Panariello Caterina Cristallini Randa Ishak Niccoletta Barbani Elisa Passaglia Serena Coiai 《Molecules (Basel, Switzerland)》2022,27(23)
To improve the capability of non-woven polypropylene-based fabric (NWF-PP) used for face mask production to retain active biomolecules such as polyphenols, the surface functionalization of NWF-PP–directly cut from face masks–was carried out by employing cold plasma with oxygen. The nature/structure of the functional groups, as well as the degree of functionalization, were evaluated by ATR-FTIR and XPS by varying the experimental conditions (generator power, treatment time, and oxygen flow). The effects of plasma activation on mechanical and morphological characteristics were evaluated by stress–strain measurements and SEM analysis. The ability of functionalized NWF-PP to firmly anchor polyphenols extracted from cloves was estimated by ATR-FTIR analysis, IR imaging, extractions in physiological solution, and OIT analysis (before and after extraction), as well as by SEM analysis. All the results obtained converge in showing that, although the plasma treatment causes changes–not only on the surface–with certain detriment to the mechanical performance of the NWF-PP, the incorporated functionalities are able to retain/anchor the active molecules extracted from the cloves, thus stabilizing the treated surfaces against thermo-oxidation even after prolonged extraction. 相似文献
87.
Caterina Gattuso Philomène Gattuso Jolanda Mastroianni Valentina Roviello Luigi Campanella 《Natural product research》2019,33(7):1078-1084
AbstractTo achieve adequate restoration project, the moment of choice of the type of intervention is a very delicate phase that necessarily involves a thorough understanding of the asset in all its aspects, as the location, the history, the architecture, the state of preservation, the pathologies causing the degradation, the degradation in itself, the analysis of constituent materials. The set of all that can be investigated on a product (cultural), to obtaining important information for subsequent maintenance, conservation and/or restoration actions, is what is called a diagnostic plan. In this case it was applied directly on a monument of national importance: the Royal Villa in Naples (today the Municipal Villa). The analysis were performed in situ and in the laboratory (SEM-EDS) on samples taken directly at the Villa, which allowed the creation of a series of analytical cards, containing digital data, required for the selection of expense future of intervention. 相似文献
88.
Kapil Shyam Lokare Beatrice Braun‐Cula Christian Limberg Marcel Jorewitz John T. Kelly Knut R. Asmis Stephen Leach Carsten Baldauf Itziar Goikoetxea Joachim Sauer 《Angewandte Chemie (International ed. in English)》2019,58(3):902-906
Even though aluminas and aluminosilicates have found widespread application, a consistent molecular understanding of their surface heterogeneity and the behavior of defects resulting from hydroxylation/dehydroxylation remains unclear. Here, we study the well‐defined molecular model compound, [Al3(μ2‐OH)3(THF)3(PhSi(OSiPh2O)3)2], 1 , to gain insight into the acid–base reactivity of cyclic trinuclear Al3(μ2‐OH)3 moieties at the atomic level. We find that, like zeolites, they are sufficiently acidic to catalyze the isomerization of olefins. DFT and gas phase vibrational spectroscopy on solvent‐free and deprotonated 1 show that the six‐membered ring structure of its Al3(μ2‐OH)3 core is unstable with respect to deprotonation of one of its hydroxy groups and rearranges into two edge‐sharing four‐membered rings. This renders AlIV?O(H)?AlIV units strong acid sites, and all results together suggest that their acidity is similar to that of zeolitic SiIV?O(H)?AlIV groups. 相似文献
89.
Beatrice Meini 《Numerische Mathematik》1997,78(1):39-58
Summary. By performing an accurate analysis of the convergence, we give a complete theoretical explanation of the experimental behaviour
of functional iteration techniques for the computation of the minimal nonnegative solution of the matrix equation , arising in the numerical solution of M/G/1 type Markov chains (here the 's are nonnegative matrices such that the matrix is column stochastic). Moreover, we introduce a general class of functional iteration methods, which includes the standard
methods, and we give an optimality convergence result in this class.
Received September 1, 1995 / Revised version received September 9, 1996 相似文献
90.
M A Macrì R Campanella G Garreffa M Occhigrossi F De Luca E Arrigoni Martelli B Maraviglia 《Magnetic resonance imaging》1992,10(5):769-772
31P NMR spectroscopy was used to assess the cerebral ischemia status in rats by measuring the relative levels of phosphate metabolites. Partial cerebral ischemia was induced in 49 rats by reversible occlusion of the carotid arteries. Rats were intubated and mechanically ventilated on a hypoxic gas mixture. Physiological parameters such as temperature and arterial pressure were strictly controlled during the experiments. 31P spectra were acquired at 7 T during basal observation, for 15-20 min after the induction of ischemia, and for 1 hr after reperfusion. Depletion and increase in PCr and Pi levels, respectively, were already observable in the collected spectra within few minutes after the onset of ischemia. No appreciable changes were found in the ATP levels. 相似文献