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31.
Ligia Bicudo de Almeida Marilene De Vuono Camargo Penteado George Britton Peter Uebelhart Murat Acemoglu Conrad Hans Eugster 《Helvetica chimica acta》1988,71(1):31-32
The 5,6:5′,6′-diepoxy-5,6:5′,6;-tetrahydro-β,β-carotene, isolated from tubers of a white-fleshed variety of sweet potato (Ipomoea batatas LAM .) has been assigned the (5R,6S,5′R,6′S)-chirality on the basis of its HPLC, UV/VIS, and CD data. 相似文献
32.
Renato Fernandes Galdiano Jr. Eliana Gertrudes de Macedo Lemos Ricardo Tadeu de Faria Wagner Aparecido Vendrame 《Applied biochemistry and biotechnology》2014,172(5):2521-2529
Vitrification, a simple, fast, and recommended cryopreservation method for orchid germplasm conservation, was evaluated for Dendrobium hybrid “Dong Yai” mature seeds. The genetic stability of regenerated seedlings was also evaluated using flow cytometry. Mature seeds from this hybrid were submitted to plant vitrification solution (PVS2) for 0, 0.5, 1, 2, 3, 4, 5, or 6 h at 0 °C. Subsequently, they were plunged into liquid nitrogen (LN) at ?196 °C for 1 h and recovered in half-strength Murashige and Skoog culture medium (1/2 MS), and seed germination was evaluated after 30 days. Seeds directly submitted to LN did not germinate after cryopreservation. Seeds treated with PVS2 between 1 and 3 h presented the best germination (between 51 and 58 %), although longer exposure to PVS2 returned moderated germination (39 %). Germinated seeds were further subcultured in P-723 culture medium and developed whole seedlings in vitro after 180 days, with no abnormal characteristics, diseases, or nutritional deficiencies. Seedlings were successfully acclimatized under greenhouse conditions with over 80 % survival. Flow cytometry analysis revealed no chromosomal changes on vitrified seedlings, as well as seedlings germinated from the control treatment (direct exposure to LN). These findings indicate that vitrification is a feasible and safe germplasm cryopreservation method for commercial Dendrobium orchid hybrid conservation. 相似文献
33.
Amanda C.R. Koike Amanda G. Santillo Flávio T. Rodrigues Renato C. Duarte Anna Lucia C.H. Villavicencio 《Radiation Physics and Chemistry》2012,81(8):1068-1070
The minimally processed food provided the consumer with a product quality, safety and practicality. However, minimal processing of food does not reduce pathogenic population of microorganisms to safe levels. Ionizing radiation used in low doses is effective to maintain the quality of food, reducing the microbiological load but rather compromising the nutritional values and sensory property. The association of minimal processing with irradiation could improve the quality and safety of product. The purpose of this study was to evaluate the effectiveness of low-doses of ionizing radiation on the reduction of microorganisms in minimally processed foods. The results show that the ionizing radiation of minimally processed vegetables could decontaminate them without several changes in its properties. 相似文献
34.
35.
Pier G. Desideri Luciano Lepri Roberto Udisti Leonardo Checchini Massimo Del Bubba Renato Cini 《International journal of environmental analytical chemistry》2013,93(3-4):331-351
Abstract Organic compounds extractable with n-hexane were identified and quantitatively determined in pack, surface and deep snow samples taken at different depths and collected at several altitudes above sea level from Antarctica during the 1993/94 Italian expedition. The comparison between the composition of organic compounds in snow and the ones in pack and sea-water samples pointed out that the three matrices substantially contain the same biogenic and anthropogenic organic compounds. The contribution of marine aerosol to organic content in the snow is confirmed by the enrichment ratios calculated for the more representative classes of identified compounds (n-alkanes, phthalates and low molecular weight alkylbenzenes). The changes in the composition of organic compounds in snow as the altitude increases seem to depend on the dimensional spectrum of the aerosol. Thus, smallest particles, richest in surfactant material, reach the highest altitudes. 相似文献
36.
R. L. Grosso J. R. Matos E. N. S. Muccillo 《Journal of Thermal Analysis and Calorimetry》2014,117(2):567-572
Zirconia containing 10 mol% scandia and x mol% dysprosia (0 ≤ x ≤ 1.5) gels was synthesized by simultaneous precipitation at room temperature. The aim of this work is to verify the effect of dysprosium on the cubic phase stabilization of the zirconia–scandia solid electrolyte. The gel was characterized by thermogravimetry, differential scanning calorimetry, and differential thermal analyses. The thermally treated powders were analyzed by Fourier transform infrared spectroscopy, thermal analyses, and X-ray diffraction techniques. For comparison purpose, a commercial zirconia–10 mol% scandia powder was subjected to some characterization techniques. The infrared spectrum shows characteristic absorption bands due to residual material from the synthesis on the surface of the powder particles. Nanostructured powders were obtained after thermal treatments at 500 °C for 2 h. Infrared spectroscopy and X-ray diffraction results evidence the stabilization of the cubic phase in zirconia–scandia containing dysprosium. The thermal stability of the cubic phase during thermal cycling was ascertained by thermal analysis. 相似文献
37.
Rosário Monteiro Gil Faria Manuela Meireles Luísa Correia‐Sá Diana Teixeira Ana Faria Conceição Calhau Valentina F. Domingues Cristina Delerue‐Matos 《Biomedical chromatography : BMC》2012,26(12):1494-1501
Scientific evidence has shown an association between organochlorine compounds (OCC) exposure and human health hazards. Concerning this, OCC detection in human adipose samples has to be considered a public health priority. This study evaluated the efficacy of various solid‐phase extraction (SPE) and cleanup methods for OCC determination in human adipose tissue. Octadecylsilyl endcapped (C18‐E), benzenesulfonic acid modified silica cation exchanger (SA), poly(styrene‐divinylbenzene (EN) and EN/RP18 SPE sorbents were evaluated. The relative sample cleanup provided by these SPE columns was evaluated using gas chromatography with electron capture detection (GC–ECD). The C18‐E columns with strong homogenization were found to provide the most effective cleanup, removing the greatest amount of interfering substance, and simultaneously ensuring good analyte recoveries higher than 70%. Recoveries > 70% with standard deviations (SD) < 15% were obtained for all compounds under the selected conditions. Method detection limits were in the 0.003–0.009 mg/kg range. The positive samples were confirmed by gas chromatography coupled with tandem mass spectrometry (GC‐MS/MS). The highest percentage found of the OCC in real samples corresponded to HCB, o,p′‐DDT and methoxychlor, which were detected in 80 and 95% of samples analyzed respectively. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
38.
Lukas Meier Christian Berchtold Stefan Schmid Renato Zenobi 《Journal of mass spectrometry : JMS》2012,47(5):555-559
In this study, we use an ion funnel (IF) at ambient pressure to enhance the sensitivity of secondary electrospray ionization (SESI). Atenolol, salbutamol and cocaine as test compounds are delivered to the SESI interface in the gas phase and are charged with three nano electrosprays. In our experiments, we show that the compounds can be detected at concentrations in the low pptv range, which is an increase of two orders of magnitude compared with the results without the IF. With a standard SESI interface, the compounds could not be detected at all. With the use of the SESI IF interface for the headspace analysis of bananas and limes, we can detect many more compounds and at higher intensities than with a standard SESI interface. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
39.
Renato Barbieri M. Teresa Musmeci 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):103-107
Abstract The title compounds, representative of classes of diorganotin (IV) derivatives active against murine leukemia P-388. interact with rat hemoglobin (selected as a model protein) by: i) co-crystallization. with formation of microcrystalline pellets, and: ii) diffusion into hemoglobin crystals from the supernatant solution (as determined for the 2-mercaptoethanesulfonato derivative). The nature of the Me2SnIV species in hemoglobin has been investigated by 119Sn Mössbauer spectroscopy, and a C2SnS2 tetrahedral geometry has been assigned by the point-charge model rationalization of the nuclear quadrupole splitting parameter. Binding into crystalline hemoglobin has been ascribed to Coulomb interactions and to hydrogen bonding between the sulfonate and the aminoacid tails of the organotin (IV) derivatives and functional groups of the globin. 相似文献
40.
Roberta A. Medeiros Roberto Matos Abdelkader Benchikh Boualem Saidani Catherine Debiemme-Chouvy Claude Deslouis Romeu C. Rocha-Filho Orlando Fatibello-Filho 《Analytica chimica acta》2013
Boron-doped diamond (BDD) films are excellent electrode materials, whose electrochemical activity for some analytes can be tuned by controlling their surface termination, most commonly either to predominantly hydrogen or oxygen. This tuning can be accomplished by e.g. suitable cathodic or anodic electrochemical pretreatments. Recently, it has been shown that amorphous carbon nitride (a-CNx) films may present electrochemical characteristics similar to those of BDD, including the influence of surface termination on their electrochemical activity toward some analytes. In this work, we report for the first time a complete electroanalytical method using an a-CNx electrode. Thus, an a-CNx film deposited on a stainless steel foil by DC magnetron sputtering is proposed as an alternative electrode for the simultaneous determination of dopamine (DA) and ascorbic acid (AA) in synthetic biological samples by square-wave voltammetry. The obtained results are compared with those attained using a BDD electrode. For both electrodes, a same anodic pretreatment in 0.1 mol L−1 KOH was necessary to attain an adequate and equivalent separation of the DA and AA oxidation potential peaks of about 330 mV. The detection limits obtained for the simultaneous determination of these analytes using the a-CNx electrode were 0.0656 μmol L−1 for DA and 1.05 μmol L−1 for AA, whereas with the BDD electrode these values were 0.283 μmol L−1 and 0.968 μmol L−1, respectively. Furthermore, the results obtained in the analysis of the analytes in synthetic biological samples were satisfactory, attesting the potential application of the a-CNx electrode in electroanalysis. 相似文献