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101.
Mariana R. Lopes Carlos J. A. de Souza Marina Q. R. B. Rodrigues Daniela A. Costa Ancély F. dos Santos Leandro L. de Oliveira Humberto J. O. Ramos Valéria M. Guimarães Wendel B. Silveira Flávia M. L. Passos Luciano G. Fietto 《Applied biochemistry and biotechnology》2014,172(5):2412-2424
An extracellular β-glucanase secreted by Kluyveromyces marxianus was identified for the first time. The optimal conditions for the production of this enzyme were evaluated by response surface methodology. The optimal conditions to produce β-glucanase were a glucose concentration of 4 % (w/v), a pH of 5.5, and an incubation temperature of 35 °C. Response surface methodology was also used to determine the pH and temperature required for the optimal enzymatic activity. The highest enzyme activity was obtained at a pH of 5.5 and a temperature of 55 °C. Furthermore, the enzyme was partially purified and sequenced, and its specificity for different substrates was evaluated. The results suggest that the enzyme is an endo-β-1,3(4)-glucanase. After optimizing the conditions for β-glucanase production, the culture supernatant was found to be effective in digesting the cell wall of the yeast Saccharomyces cerevisiae, showing the great potential of β-glucanase in the biotechnological production of soluble β-glucan. 相似文献
102.
Dr. Igor L. Dalinger Dr. Irina A. Vatsadze Dr. Tatyana K. Shkineva Dr. Alexandr V. Kormanov Dr. Marina I. Struchkova Dr. Kyrill Yu. Suponitsky Dr. Anatoly A. Bragin Dr. Konstantin A. Monogarov Dr. Valery P. Sinditskii Dr. Aleksei B. Sheremetev 《化学:亚洲杂志》2015,10(9):1987-1996
A new family of energetic compounds, nitropyrazoles bearing a trinitromethyl moiety at the nitrogen atom of the heterocycle, was designed. The desirable high‐energy dense oxidizers 3,4‐dinitro‐ and 3,5‐dinitro‐1‐(trinitromethyl)pyrazoles were synthesized in good yields by destructive nitration of the corresponding 1‐acetonylpyrazoles. All of the prepared compounds were fully characterized by multinuclear NMR and IR spectroscopy, as well as by elemental analysis. Single‐crystal X‐ray diffraction studies show remarkably high density. Impact sensitivity tests and thermal stability measurements were also performed. All of the pyrazoles possess positive calculated heats of formation and exhibit promising energetic performance that is the range of 1,3,5‐trinitroperhydro‐1,3,5‐triazine and pentaerythritol tetranitrate. The new pyrazoles exhibit positive oxygen balance and are promising candidates for new environmentally benign energetic materials. 相似文献
103.
Mario Olivieri Gianluca Spiteri Jessica Brandi Daniela Cecconi Marina Fusi Giovanna Zanoni Corrado Rizzi 《Molecules (Basel, Switzerland)》2022,27(4)
Wheat allergens are responsible for symptoms in 60–70% of bakers with work-related allergy, and knowledge, at the molecular level, of this disorder is progressively accumulating. The aim of the present study is to investigate the panel of wheat IgE positivity in allergic Italian bakers, evaluating a possible contribution of novel wheat allergens included in the water/salt soluble fraction. The water/salt-soluble wheat flour proteins from the Italian wheat cultivar Bolero were separated by using 1-DE and 2-DE gel electrophoresis. IgE-binding proteins were detected using the pooled sera of 26 wheat allergic bakers by immunoblotting and directly recognized in Coomassie stained gel. After a preparative electrophoretic step, two enriched fractions were furtherly separated in 2-DE allowing for detection, by Coomassie, of three different proteins in the range of 21–27 kDa that were recognized by the pooled baker’s IgE. Recovered spots were analyzed by nanoHPLC Chip tandem mass spectrometry (MS/MS). The immunodetected spots in 2D were subjected to mass spectrometry (MS) analysis identifying two new allergenic proteins: a glucose/ribitol dehydrogenase and a 16.9 kDa class I heat shock protein 1. Mass spectrometer testing of flour proteins of the wheat cultivars utilized by allergic bakers improves the identification of until now unknown occupational wheat allergens. 相似文献
104.
Marina A. Medvedeva Theodore E. Simos Charalampos Tsitouras 《Mathematical Methods in the Applied Sciences》2020,43(4):1582-1589
Implicit Runge-Kutta (RK) methods are in common use when addressing stiff initial value problems (IVP). They usually share the property of A-stability that is of crucial importance in solving the latter type of IVP. Radau IIA family of implicit RK methods is among the preferred ones. Especially its fifth-order representative named RADAU5 has received a lot of attention for use with lax accuracies. Here, we try the lesser possible perturbation of its coefficients. Then, we derive a trigonometric fitted modification that is intended to be applied in periodic IVPs. Numerical tests over a variety of problems with oscillatory solutions justify our effort. 相似文献
105.
Pump−probe experiments at the TEMPO beamline using the low‐α operation mode of Synchrotron SOLEIL 下载免费PDF全文
Mathieu G. Silly Tom Ferté Marie Agnes Tordeux Debora Pierucci Nathan Beaulieu Christian Chauvet Federico Pressacco Fausto Sirotti Horia Popescu Victor Lopez-Flores Marina Tortarolo Maurizio Sacchi Nicolas Jaouen Philippe Hollander Jean Paul Ricaud Nicolas Bergeard Christine Boeglin Bharati Tudu Renaud Delaunay Jan Luning Gregory Malinowski Michel Hehn Cédric Baumier Franck Fortuna Damjan Krizmancic Luigi Stebel Rudi Sergo Giuseppe Cautero 《Journal of synchrotron radiation》2017,24(4):886-897
The SOLEIL synchrotron radiation source is regularly operated in special filling modes dedicated to pump–probe experiments. Among others, the low‐α mode operation is characterized by shorter pulse duration and represents the natural bridge between 50 ps synchrotron pulses and femtosecond experiments. Here, the capabilities in low‐α mode of the experimental set‐ups developed at the TEMPO beamline to perform pump–probe experiments with soft X‐rays based on photoelectron or photon detection are presented. A 282 kHz repetition‐rate femtosecond laser is synchronized with the synchrotron radiation time structure to induce fast electronic and/or magnetic excitations. Detection is performed using a two‐dimensional space resolution plus time resolution detector based on microchannel plates equipped with a delay line. Results of time‐resolved photoelectron spectroscopy, circular dichroism and magnetic scattering experiments are reported, and their respective advantages and limitations in the framework of high‐time‐resolution pump–probe experiments compared and discussed. 相似文献
106.
Diana C. Skigin Miriam L. Gigli Marina E. Inchaussandague Néstor E. Bonomo Claudio I. Valencia 《International Journal of Infrared and Millimeter Waves》1993,14(6):1323-1339
Theoriginal and theenhanced Maxwell-Garnett estimates for the permittivity of a particulate medium are applied to the reflection of light by a composite dielectric slab. The reflection coefficients for incident s and p polarizations are calculated and some curves are plotted and discussed. 相似文献
107.
We have analysed the spatial coherence of polarized radiation scattered in a random magnetoplasma. The major result is the prediction of a relative enhancement of the linear polarization fraction of received radiation for higher-order spatial harmonics. This is due to the scattering on the magnetic field irregularities in a random magnetoplasma. This effect may be detectable in the case of propagation of linearly polarized radiation through the terrestrial magnetosphere, or Jovian ionosphere, or the solar chromosphere. The relative enhancement in the content of linear polarization is due to a general property, namely chirality of the magnetoplasma, and hence may have general applications to chiral media, specifically as a means of analysing the spatial distribution in material specimens. 相似文献
108.
Marina Sicignano Dr. Rosaria Schettini Luisa Sica Giovanni Pierri Prof. Dr. Francesco De Riccardis Prof. Dr. Irene Izzo Dr. Bholanath Maity Dr. Yury Minenkov Prof. Dr. Luigi Cavallo Dr. Giorgio Della Sala 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(29):7131-7141
The first highly enantioselective arylogous Michael reaction (AMR) of 3-unsubstituted phthalides has been described. This phase-transfer methodology, which uses catalytic amounts of KOH/18-crown-6 catalyst in mesitylene in the presence of N,O-bis(trimethylsilyl)acetamide (BSA), gives access to a broad range of 3-monosubstituted phthalides with high levels of syn diastereoselectivity and good yields, starting from 3-unsubstituted derivatives and diverse α,β-unsaturated carbonyl compounds. The reaction also applies to unactivated 3-alkyl phthalides to afford 3,3-dialkyl derivatives. A plausible mechanism has been suggested. DFT analysis of possible transition states gives a rationale of the high syn diastereoselectivity observed and its correlation with the solvent's dielectric constant. 相似文献
109.
Prof. Richard D. Adams Dr. Poonam Dhull Matthew Pennachio Prof. Marina A. Petrukhina Dr. Mark D. Smith 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(16):4234-4239
The reaction of Re2(CO)8(μ-C6H5)(μ-H), 1 with corannulene (C20H10) yielded the product Re2(CO)8(μ-H)(μ-η2-1,2-C20H9), 2 (65 % yield) containing a Re2 metalated corannulene ligand formed by loss of benzene from 1 and the activation of one of the CH bonds of the nonplanar corannulene molecule by an oxidative-addition to 1 . The corannulenyl ligand has adopted a bridging η2-σ+π coordination to the Re2(CO)8 grouping. Compound 2 reacts with a second equivalent of 1 to yield three isomeric doubly metalated corannulene products: Re2(CO)8(μ-H)(μ-η2-1,2-μ-η2-10,11-C20H8)Re2(CO)8(μ-H), 3 (35 % yield), Re2(CO)8(μ-H)(μ-η2-2,1-μ-η2-10,11-C20H8)Re2(CO)8(μ-H), 4 (12 % yield), and Re2(CO)8(μ-H)(μ-η2-1,2-μ-η2-11,10-C20H8)Re2(CO)8(μ-H), 5 (12 % yield), by a second CH activation on a second rim double bond on the corannulene molecule. The isomers differ by the relative orientations of the coordinated Re2(CO)8(μ-H) groupings. All new products were characterized structurally by single crystal X-ray diffraction analysis. 相似文献
110.
Dmitry I. Bugaenko Alexey A. Volkov Dr. Mikhail V. Livantsov Prof. Dr. Marina A. Yurovskaya Dr. Alexander V. Karchava 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(54):12502-12506
The visible-light-induced arylation of tertiary phosphines with aryl(mesityl)iodonium triflates to produce the quaternary phosphonium salts occurs under mild, metal, and catalyst-free conditions. Photo-excited EDA complexes between diaryliodonium salts and phosphines supposedly enable this transformation, which is difficult to achieve through the traditional ground-state reactions. Demonstrating high functional group tolerance, broad scope, and complete selectivity of the aryl group transfer, the method is particularly compatible with sterically congested phosphines, which are challenging under metal-based catalytic methods. 相似文献