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941.
Gabriel Beltrn Carmen del Río Sebastin Snchez Leopoldo Martínez 《Journal of the science of food and agriculture》2004,84(13):1783-1790
Olive fruits of three of the most important Spanish and Italian cultivars, ‘Picual’, ‘Hojiblanca’ and ‘Frantoio’, were harvested at bi‐weekly periods during three crop seasons to study their development and ripening process. Fresh and dry weights and ripening index were determined for fruit, while dry matter, oil and moisture contents were determined in both fruit and pulp (flesh). Fruit growth rate and oil accumulation were calculated. Each olive cultivar showed a different ripening pattern, ‘Hojiblanca’ being the last one to maturate. Fruit weight increased, decreasing its growth rate from the middle of November. Dry matter and moisture contents decreased during ripening in pulp and fruit, ‘Hojiblanca’ showing the highest values for both. Oil content, when expressed on a fresh weight basis, increased in all cultivars, although for the last time period showed variations due to climatic conditions. During ripening, oil content on a dry weight basis increased in fruit, but oil biosynthesis in flesh ceased from November. Olive fruits presented lower oil and higher dry matter contents in the year of lowest rainfall. Therefore fruit harvesting should be carried out from the middle of November in order to obtain the highest oil yield and avoid natural fruit drop. Copyright © 2004 Society of Chemical Industry 相似文献
942.
Rodriguez P Alfonso A Vale C Alfonso C Vale P Tellez A Botana LM 《Analytical chemistry》2008,80(14):5622-5629
Tetrodotoxin (TTX) is one of the most potent toxins already isolated, which occurs in a wide variety of animals. In this work, the occurrence of TTX and analogues was examined using mass spectrometry, confocal microscopy, liquid chromatography-mass spectrometry (LC-MS), and mouse bioassay in a trumpet shell (Charonia lampas lampas) and in the fluids of a patient poisoned by consuming this shell. Retention time data in the LC-MS system within the enhanced mass spectrum (EMS) mode indicated the presence of TTX and the analogue 5,6,11-trideoxyTTX; the enhanced product ion (EPI) mode confirmed the existence of both toxins with the formation of characteristic daughter ions from the fragment pattern of each molecule. TTX and 5,6,11-trideoxyTTX were only detected in the digestive gland of the trumpet shell and also in the urine and serum of the patient. The concentration of 5,6,11-trideoxyTTX checked in the samples by LC-MS was 3 times higher than TTX. However, the results obtained by mouse bioassay showed that the analogue is much less toxic than TTX. In vitro toxicity was checked using cerebellar cells; in these experiments the trumpet shell sample showed high toxicity, but the level was lower than in vivo results probably due to some competition between analogues. This paper shows for first time the presence and toxicity of TTX and 5,6,11-trideoxyTTX in a trumpet shell collected in the European coasts. The LC-MS method is a useful tool to confirm the presence of TTX and the further identification of TTX analogues. 相似文献
943.
In this study, the authors used a within-person design to examine the relation between recovery experiences (psychological detachment, relaxation, mastery experiences) during leisure time, sleep, and affect in the next morning. Daily survey data gathered over the course of 1 work week from 166 public administration employees analyzed with a hierarchical linear modeling approach showed that low psychological detachment from work during the evening predicted negative activation and fatigue, whereas mastery experiences during the evening predicted positive activation and relaxation predicted serenity. Sleep quality showed relations with all affective states variables. This study adds to research on job-stress recovery and affect regulation by showing which specific experiences from the nonwork domain may improve affect before the start of the next working day. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
944.
María Jesús Oliveras‐López José Javier Quesada Granados Francisco Martín Bermudo Herminia López‐García de la Serrana Maria del Carmen López Martínez 《European Journal of Lipid Science and Technology》2008,110(6):530-536
The aim of this study was to estimate the α‐tocopherol content in Picual extra‐virgin olive oils obtained from the 2004/2005 harvesting season and to evaluate the influence that different extraction processes and sample handling had on the final vitamin E content in the oils. A new experimental oil extraction carried out at 9 °C enabled us to obtain encouragingly high quantities of α‐tocopherol with an average quantity reaching 341.34 ± 50.17 mg/L (n = 13), with significant differences among the same oil types produced from the traditional two‐phase system at low (9 °C, p <0.01) and moderate (21.5 °C, p <0.001; 33 °C, p <0.0001) temperatures. The temperature at which extraction was carried out should be considered as a major factor to be taken into account. Additionally, we also developed a precise method for the extraction of α‐tocopherol from olive oil samples, which enables high recovery (96 ± 2%) for use in subsequent HPLC/DAD/fluorescence quantification. 相似文献
945.
Munoz-Olaya JM Matabosch X Bedia C Egido-Gabás M Casas J Llebaria A Delgado A Fabriàs G 《ChemMedChem》2008,3(6):946-953
A novel mechanism-based dihydroceramide desaturase inhibitor (XM462) in which the substrate C5 methylene group is replaced by a sulfur atom is reported. Dihydroceramide desaturase inhibition occurred both in vitro and in cultured cells with IC(50) values of 8.2 and 0.78 microM, respectively, at a substrate concentration of 10 microM. In vitro experiments showed that XM462 produced a mixed-type inhibition (K(i)=2 microM, alpha=0.83). LC-MS analyses showed that accumulation of endogenous dihydroceramides occurred in cells upon treatment with XM462 in serum-free medium, whereas ceramides built up in controls. In addition, XM462 was found to be metabolised to its 1-glucosyl and 1-phosphocholine derivatives, and to the products of N-deacylation and reacylation with palmitoyl and stearoyl groups. In Jurkat A3 cells cultured in serum-free medium, viability, as the percentage of trypan blue unstained cells in total cells, was reduced upon XM462 treatment (5 microM, 24 h), but not in controls. The interest of this compound is discussed. 相似文献
946.
Rey-Salgueiro L García-Falcón MS Martínez-Carballo E González-Barreiro C Simal-Gándara J 《The Science of the total environment》2008,406(1-2):279-286
PAHs from a polluted atmosphere are generally transferred to plants by particle-phase deposition on the waxy leaf cuticle or by uptake in the gas phase through stomata. Thus, they are also present in ingredients for animal feed. Generally, toxic substances are metabolized before or after absorption through the intestinal tract. This is the case of 3-hydroxybenzo[a]pyrene, which can be found free or in its glucuronide and/or sulphate conjugate forms. This article develops a procedure to monitor the carry-over of PAHs from feed to food of animal origin based on the analysis of animal manure. Eleven PAHs and 3-hydroxybenzo[a]pyrene were measured in four animal manures (cow, horse, rabbit and pig) by liquid chromatography with fluorescence detection. benzo[a]pyrene, benzo[b]fluoranthene and benzo[k]fluoranthene were found in all the selected samples, but their total levels were not alarming (benzo[a]pyrene equivalents (microg/kg)<3.1). 3-hydroxybenzo[a]pyrene was quantified in all the samples exempting rabbit manure. The highest total PAH levels were detected in cow manure (9.0 microg/kg), while the highest 3-OH-B[a]P level was determined in horse samples (13 microg/kg). 相似文献
947.
The surface effect from surface stress and surface elasticity on the elastic behavior of nanowires in static bending is incorporated into Euler-Bernoulli beam theory via the Young-Laplace equation. Explicit solutions are presented to study the dependence of the surface effect on the overall Young's modulus of nanowires for three different boundary conditions: cantilever, simply supported, and fixed-fixed. The solutions indicate that the cantilever nanowires behave as softer materials when deflected while the other structures behave like stiffer materials as the nanowire cross-sectional size decreases for positive surface stresses. These solutions agree with size dependent nanowire overall Young's moduli observed from static bending tests by other researchers. This study also discusses possible reasons for variations of nanowire overall Young's moduli observed. 相似文献
948.
Wearable Sensors: Flexible Piezoresistive Sensor Patch Enabling Ultralow Power Cuffless Blood Pressure Measurement (Adv. Funct. Mater. 8/2016) 下载免费PDF全文
949.
950.
Cabrera C Lloris F Giménez R Olalla M López MC 《The Science of the total environment》2003,308(1-3):1-14
We evaluated the levels of essential elements as Cu, Cr, Fe and Zn, and toxic elements as Al, Ni, Pb and Cd in a total of 40 samples of different legumes and 56 samples of different nuts, that are widely consumed in Spain. These elements were determined in the samples mineralized with HNO(3) and V(2)O(5), using electrothermal atomic absorption spectrometry (ETAAS) as the analytical technique. Reliability of the procedure was checked by analysis of a certified reference material. No matrix effects were observed and aqueous standard solutions were used for calibration. In legumes, the levels ranged from 1.5-5.0 microg Cu/g, 0.05-0.60 microg Cr/g, 18.8-82.4 microg Fe/g, 32.6-70.2 microg Zn/g, 2.7-45.8 microg Al/g, 0.02-0.35 microg Ni/g, 0.32-0.70 microg Pb/g and not detectable-0.018 microg Cd/g. In nuts, the levels ranged from 4.0-25.6 microg Cu/g, 0.25-1.05 microg Cr/g, 7.3-75.6 microg Fe/g, 25.6-69.0 microg Zn/g, 1.2-20.1 microg Al/g, 0.10-0.64 microg Ni/g, 0.14-0.39 microg Pb/g, and not detectable-0.018 microg Cd/g. A direct statistical correlation between Cu-Cr, Zn-Al and Cr-Ni (P<0.05), and Al-Pb (P<0.001), has been found. The growing popularity of these products in recent years on the basis of its nutritional properties and beneficial effects, requires additional data and a periodical control. In addition, the present findings are of potential use to food composition tables. 相似文献