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111.
Luciano Di Maio Pio Iannelli Stefania Pragliola Antonio Roviello Augusto Sirigu 《Journal of Polymer Science.Polymer Physics》1998,36(3):433-438
Preliminary results on the synthesis and characterization of anisotropic networks, oriented on a macroscopic scale, are reported. Fiber samples of segmented thermotropic liquid-crystalline polymers bearing the oxypentenyl lateral substituent have been crosslinked via thermally activated radical reaction. This was made possible by immersion of fiber samples in dichloromethane containing t-butylperoxybenzoate as activating agent, thus allowing its diffusion in the samples. Subsequent annealing at 145°C brings us to an anisotropic network with no loss of the original orientation. A mesophase is stabilized and no structural modification is observed by heating samples from room temperature up to 400°C, where thermal decomposition takes place. Crosslinked fibers exhibit good tensile properties, at both room temperature and at 150°C. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 433–438, 1998 相似文献
112.
Victor Hugo Catricala Fernandes Natalie de Barros Viera Luiza Beatriz Lima Zanini Aline de Fátima Silva Paula Pio de Oliveira Salem Marisi Gomes Soares Karen de Jesus Nicácio Ana Claudia Chagas de Paula Luciano Sindra Virtuoso Tiago Branquinho Oliveira Eliane de Oliveira Silva Danielle Ferreira Dias Daniela Aparecida Chagas-Paula 《Photochemistry and photobiology》2020,96(1):14-20
There is some evidence in the literature of the photocyclization reaction of Tagitinin C ( 1 ) to Tagitinin F ( 2 ). Compound 2 has high pharmacological potential, but it is not easy to obtain, while compound 1 is easily obtained from a widespread plant, Tithonia diversifolia. Among different reaction conditions monitored, one was found that allowed the cyclization of 1 into 2 in <15 min in a photo-dependent reaction. Scaling-up the photocyclization of the pure compound 1 into 2 demonstrated 100% yield, and the isolation of 2 from a UV-irradiated extract was eight-fold higher than the quantity isolated from the non-UV-irradiated extract. We were also able to better understand the process of photoconversion and determine methods to isolate and quantify these compounds, which are known for their important antitumoral activities among other important pharmacological properties. 相似文献
113.
Fabiana Fuentes-León Andressa Peres de Oliveira Nathalia Quintero-Ruiz Veridiana Munford Gustavo Satoru Kajitani Antônio Coimbra Brum André Passaglia Schuch Pio Colepicolo Angel Sánchez-Lamar Carlos Frederico Martins Menck 《Photochemistry and photobiology》2020,96(6):1215-1220
Sunlight ultraviolet (UV) radiation constitutes an important environmental genotoxic agent that organisms are exposed to, as it can damage DNA directly, generating pyrimidine dimers, and indirectly, generating oxidized bases and single-strand breaks (SSBs). These lesions can lead to mutations, triggering skin and eye disorders, including carcinogenesis and photoaging. Stratospheric ozone layer depletion, particularly in the Antarctic continent, predicts an uncertain scenario of UV incidence on the Earth in the next decades. This research evaluates the DNA damage caused by environmental exposure to late spring sunlight in the Antarctic Peninsula, where the ozone layer hole is more pronounced. These experiments were performed at the Brazilian Comandante Ferraz Antarctic Station, at King’s George Island, South Shetlands Islands. For comparison, tropical regions were also analyzed. Samples of plasmid DNA were exposed to sunlight. Cyclobutane pyrimidine dimers (CPDs), oxidized base damage and SSBs were detected using specific enzymes. In addition, an immunological approach was used to detect CPDs. The results reveal high levels of DNA damage induced by exposure under the Antarctic sunlight, inversely correlated with ozone layer thickness, confirming the high impact of ozone layer depletion on the DNA damaging action of sunlight in Antarctica. 相似文献
114.
115.
Guaratini T Gates PJ Cardozo KH Campos PM Colepicolo P Lopes NP 《European journal of mass spectrometry (Chichester, England)》2006,12(1):71-74
This paper reports a preliminary study of the nanospray ionisation mass spectrometry analyses of retinoic acid and retinal. The results are compared and contrasted to the results normally observed with electrospray ionisation. A significant difference in behaviour was observed for the balance between radical ion formation and protonated molecule formation for retinal. The results suggest that the influence of the very different ionisation conditions present in nanospray is very important in determining how ionisation is achieved and has potentially wide ranging applications in the fields of mass spectral analysis of biological and medical extracts. 相似文献
116.
Hans A. V. Kistemaker Dr. Aurelio Pio Nardozza Prof. Dr. Herman S. Overkleeft Prof. Dr. Gijs A. van der Marel Prof. Dr. Andreas G. Ladurner Dr. Dmitri V. Filippov 《Angewandte Chemie (International ed. in English)》2016,55(36):10634-10638
Mono‐ADP‐ribosylation is a dynamic posttranslational modification (PTM) with important roles in signaling. Mammalian proteins that recognize or hydrolyze mono‐ADP‐ribosylated proteins have been described. We report the synthesis of ADP‐ribosylated peptides from the proteins histone H2B, RhoA and, HNP‐1. An innovative procedure was applied that makes use of pre‐phosphorylated amino acid building blocks. Binding assays revealed that the macrodomains of human MacroD2 and TARG1 exhibit distinct specificities for the different ADP‐ribosylated peptides, thus showing that the sequence surrounding ADP‐ribosylated residues affects the substrate selectivity of macrodomains. 相似文献
117.
Joe Iannelli 《国际流体数值方法杂志》2013,72(2):157-176
An exact similarity solution of the compressible‐flow Navier–Stokes equations is presented, which embeds supersonic, transonic, and subsonic regions. Describing the viscous and heat‐conducting high‐gradient flow in a shock wave, the solution accommodates non‐linear temperature‐dependent viscosity as well as heat‐conduction coefficients and provides the variation of all the flow variables and their derivatives. Also presented are methods to obtain time‐dependent and/or multi‐dimensional solutions as well as verification benchmarks of increasing severity. Comparisons between the developed analytical solution and CFD solutions of the Navier–Stokes equations, with determination of convergence rates and orders of accuracy of these solutions, illustrate the utility of the developed exact solution for verification purposes. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
118.
Joe Iannelli 《国际流体数值方法杂志》2003,43(4):369-406
This paper details a two‐equation procedure to calculate exactly mass and mole fractions, pressure, temperature, specific heats, speed of sound and the thermodynamic and jacobian partial derivatives of pressure and temperature for a five‐species chemically reacting equilibrium air. The procedure generates these thermodynamic properties using as independent variables either pressure and temperature or density and internal energy, for CFD applications. An original element in this procedure consists in the exact physically meaningful solution of the mass‐fraction and mass‐action equations. Air‐equivalent molecular masses for oxygen and nitrogen are then developed to account, within a mixture of only oxygen and nitrogen, for the presence of carbon dioxide, argon and the other noble gases within atmospheric air. The mathematical formulation also introduces a versatile system non‐dimensionalization that makes the procedure uniformly applicable to flows ranging from shock‐tube flows with zero initial velocity to aerothermodynamic flows with supersonic/hypersonic free‐stream Mach numbers. Over a temperature range of more than 10000 K and pressure and density ranges corresponding to an increase in altitude in standard atmosphere of 30000 m above sea level, the predicted distributions of mole fractions, constant‐volume specific heat, and speed of sound for the model five species agree with independently published results, and all the calculated thermodynamic properties, including their partial derivatives, remain continuous, smooth, and physically meaningful. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
119.
Clemenza Massimiliano Bonesini Maurizio Carpinelli Massimo Cremonesi Oliviero Fiorini Ettore Gorini Giuseppe Hillier Adrian Ishida Katsu Menegolli Alessandro Mocchiutti Emiliano Oliva Piernicola Prata Marco Rendeli Marco Rignanese Luigi Pio Rossella Massimo Sipala Valeria Soldani Mattia Tortora Ludovico Vacchi Andrea Vallazza Erik 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(3):1357-1363
Journal of Radioanalytical and Nuclear Chemistry - The implementation in the RIKEN-RAL negative muons facility of a new muon beamline monitoring and novel digital data acquisition system for gamma... 相似文献
120.