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51.
Simultaneous HPLC quantification of total cholesterol,tocopherols and β-carotene in Barrosã-PDO veal 总被引:1,自引:0,他引:1
José A. Mestre Prates Mário A. Gonçalves Quaresma Rui J. Branquinho Bessa Carlos M.G. Andrade Fontes Cristina M.P. Mateus Alfaia 《Food chemistry》2006
A simple, rapid and sensitive procedure for the simultaneous determination of total cholesterol, tocopherols and β-carotene in meat is described. The method involves a direct saponification of the meat, a single n-hexane extraction and the analysis of the extracted compounds by normal-phase HPLC, using fluorescence (tocopherols) and UV–Vis photodiode array (cholesterol and β-carotene) detections in tandem. Rates of recovery of spiked meat samples were 93% for cholesterol, 83–86% for (α-, β- and -γ) tocopherols and 89% for β-carotene. Repeatabilities were high (CV < 6%) for all determined compounds, except for δ-tocopherol. This tocopherol, which is not usually present in meat, showed a much lower recovery percentage (73%) and repeatability (12.8%). This methodology was applied for the quantification of total cholesterol, tocopherols and β-carotene in three muscles (longissimus thoracis, longissimus lumborum and semitendinosus) of the Portuguese traditional Barrosã-PDO veal, obtained from autochthonous calves fed extensively during summer (with the least abundant green pastures) and slaughtered in early autumn (October). Barrosã-PDO veal showed median contents of total cholesterol (0.50–0.56 mg/g) and, depending on the analysed muscle, moderate to high contents of α-tocopherol (3.3–3.9 μg/g) and β-carotene (0.07–0.09 μg/g), suggesting an high sensorial and hygienic quality. 相似文献
52.
Influence of electroosmotic treatment on the hydro-mechanical behaviour of clayey silts: preliminary experimental results 总被引:1,自引:0,他引:1
Laura Gabrieli Cristina Jommi Guido Musso Enrique Romero 《Journal of Applied Electrochemistry》2008,38(7):1043-1051
Preliminary results of an investigation focused on the influence of electrokinetic treatment on the mechanical and hydraulic
behaviour of clayey soils are presented. The experimental programme aims at providing a contribution to the sustainability
of contaminant extraction or containment via electroosmosis. Changes in the hydraulic and mechanical properties of two illitic
clayey soils, subjected to a DC electric field, were investigated. Samples of the two soils were subjected to electrokinetic
filtration, for different periods of time, and under different constant loads. Afterwards, they were tested under one-dimensional
compression to detect changes in stiffness and hydraulic conductivity due to the electrical treatment. After the application
of a DC field for a few hours, a small reversible increment in the average soil stiffness was observed, with respect to the
untreated soil, while the hydraulic conductivity was not affected substantially. Dramatic changes of the mechanical and hydraulic
soil properties, correlated to changes of the soil pH, were observed following non-conditioned electrokinetic treatment with
duration of the order of days. 相似文献
53.
Jaime Ortiz Óscar Palma Natalia González Santiago P. Aubourg 《European Journal of Lipid Science and Technology》2008,110(12):1127-1135
The flow ice system including ozone (OFI condition) was tested for slaughtering and storage (up to 16 days) of farmed rainbow trout (Oncorhynchus mykiss). Lipid damage analyses were carried out and compared to sensory acceptance and instrumental colour changes. Comparison to individuals processed with the flow ice system in the absence of ozone (FI condition) was undertaken. Rainbow trout slaughtered and chilled under FI and OFI conditions showed a low lipid damage development, according to lipid oxidation and hydrolysis events and lipid composition (polyunsaturated fatty acids, phospholipids and endogenous antioxidants) changes. Additionally, both icing conditions led to largely good quality and shelf life times and to the absence of changes in colour properties. It is concluded that flow ice as such, or including the presence of ozone, can be considered as ideal strategy to be employed as slaughtering and storage system during the commercialisation of the actual farmed species. The ozone presence has shown some profitable effects as leading to an extended shelf life time by quality retention of several sensory parameters; in contrast, some negligible negative effects could be observed on the secondary and tertiary lipid oxidation development. However, the oxidation values reached by individuals kept under OFI conditions cannot be considered as particularly high. 相似文献
54.
R Centurioni P Leoni M Candela M Cristina Refe A Stella Strusi L Fabietti G Danieli 《Canadian Metallurgical Quarterly》1996,87(4):161-163
In absence of thrombocytosis, periodic bloodlettings represent the elective therapy of polycythemia vera. In the present study we tested if neocytoapheresis, a method able to remove large quantities of younger, and then bigger red cells could represent an alternative therapeutic choice in these patients. We found that the employment of neocytoapheresis produced a remarkable delay in the time of procedures with a mean interval of 100 +/- 55 days. The mean value of hematocrit before neocytopheresis is resulted statistically different in comparison with the hematocrit after the procedure (p = 0.0001). The reticulocyte count is resulted higher in apheresis product in comparison with the blood control measured before procedure (p = 0.0001). In the same way, the mean corpuscular volume in the collection bags was higher than the volume measured before neocytoapheresis (p = 0.0095). We did not find any variation about the mean values of white blood cells and platelets before and after neocytoapheresis in the patients examined. These preliminary data seem to underline a better withdrawal of big size cells by this technique suggesting the efficacy of neocytoapheresis in the treatment of polycythemia vera. 相似文献
55.
56.
The aim of the present study was to determine the origin of the catecholaminergic inputs to the telencephalic basal ganglia of amphibians. For that purpose, retrograde tracing techniques were combined with tyrosine hydroxylase immunohistochemistry in the anurans Xenopus laevis and Rana perezi and the urodele Pleurodeles waltl. In all three species studied, a topographically organized dopaminergic projection was identified arising from the posterior tubercle/mesencephalic tegmentum and terminating in the striatum and the nucleus accumbens. Although essentially similar, the organization of the mesolimbic and mesostriatal connections in anurans seems to be more elaborate than in urodeles. The present study has also revealed the existence of a noradrenergic projection to the basal forebrain, which has its origin in the locus coeruleus. Additional catecholaminergic afferents to the striatum and the nucleus accumbens arise from the nucleus of the solitary tract, where catecholaminergic neurons appear to give rise to the bulk of the projections to the basal forebrain. In other regions, such as the olfactory bulb, the anterior preoptic area, the suprachiasmatic nucleus, and the thalamus, retrogradely labeled neurons (after basal forebrain tracer-applications) and catecholaminergic cells were intermingled, but none of these centers contained double-labeled cell bodies. It is concluded that the origin of the catecholaminergic innervation of the striatum and the nucleus accumbens in amphibians is largely comparable to that in amniotes. The present study, therefore, strongly supports the existence of a common pattern in the organization of the catecholaminergic inputs to the basal forebrain among tetrapod vertebrates. 相似文献
57.
MJ Fernández Ace?ero J Farina González P Arangoncillo Ballesteros 《Canadian Metallurgical Quarterly》1997,142(5-6):289-296
We have performed immunohistochemical staining for p53 and c-erbB-2 on formaldehyde-fixed, paraffin-embedded primary invasive ductal carcinomas from 112 patients, with a minimal follow-up time of 60 months. All of them had received postoperative chemoradiation therapy. We have analyzed the association of these factors with epidemiologic risk factors, histopathologic features and hormonal receptor status and the influence on prognosis. Our results indicate that the expression of c-erbB-2 protein defines a group of node-negative patients with poor prognosis. The overexpression of c-erbB-2 has shown a significant association with estrogen receptor status (those tumors expressing c-erbB-2 are usually estrogen receptor negative), presence of fibrosis and lymphoplasmacytoid infiltrates. P53 expression has shown no relation either with prognosis or with any other histopathologic or clinical feature. The only factors with prognostic influence in our series have been tumor size, the presence of node metastases, TNM stage and the prognostic morphometric index (Baak's index), apart from c-erbB-2 in node-negative patients. However, only the TNM stage showed an independent association with prognosis after a multivariate analysis. In summary, in our experience the expression of p53 protein has no prognostic influence on breast carcinoma, and TNM stage remains to be as the most powerful prognostic factor in these patients. 相似文献
58.
Visually perceiving an action may activate corresponding motor programs. This automatic motor activation can occur both for higher level (i.e., the goal of an action) and for lower level (i.e., the specific effector with which it is executed) aspects of an action. The authors used a tool-use action paradigm to experimentally dissociate priming effects for observing the target, the movement, or the target-to-movement mapping of a tool-use action. In 3 experiments, participants took turns in acting, observing the tool-use action of another person in trial n-1, and executing an action in trial n. Trial transitions from n-1 to n were manipulated in 4 conditions with (a) mapping repeated and movement and target changed, (b) target repeated and movement and mapping changed, (c) movement repeated and target and mapping changed, or (d) all components repeated. Results indicate priming effects for repeating the target-to-movement mapping (i.e., the action rule) of a tool-use action and suggest that a rather abstract action schema is activated during action observation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
59.
Vicente Ferreira Cristina Peña Ana Escudero Juan Cacho 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1996,202(4):318-323
The ability of fermentative CO2 to blow off the volatile compounds that are synthesized during fermentation has been studied. Model solutions simulating a fermenting must were purged at different CO2 flow rates and temperatures, and the amount of volatile compounds blown off by the stream of CO2 was recorded by high-resolution gas chromatography. Data showed that under normal fermenting conditions, fatty acid ethyl esters and some fusel alcohol acetates are blown off the solution at a high rate. The maximum loss rate was observed for ethyl decanoate. The purging speed is doubled when temperature increases from 17 °C to 27 °C. Losses can be interpreted by a linear model and are a function of the compound and the flow rate of CO2. These models allow us to reconstruct the volatile synthesis vs time functions through graphic calculus and to estimate the proportion of volatile material retained, hydrolysed and purged. Synthesis takes place during the tumultuous period of fermentation together with CO2 production that blows off the volatile material. Hydrolysis takes place in the last stages of fermentation. In a 10-1 open fermenter, up to 80% of volatile material can be blown off while an average of 10% is retained. Residual esterase activity accounts for about 20% of the total amount of ester synthesized. 相似文献
60.
This work presents a series of results about the synthesis and characterization of porous oxide thin films (thicknesses ∼
∼300 nm) prepared at low temperature by PECVD. Two different experimental strategies are described. A first one, used for
the preparation of porous SiO2 thin films, consists of the use of a polymeric sacrificial layer that is removed during deposition of the oxide thin film.
A second one, used for the preparation of TiO2 thin films, relies on the modification of some critical deposition parameters (i.e., temperature, Ar/O2 ratio in the plasma mixture, etc.). Thin films with a large variation of pore structures as evidenced by Scanning Electron
Microscopy (SEM) have been prepared by the two methodologies. The thin films have been characterised by different techniques
and some of their properties related with their microstructure assessed by ellipsometry (optical behaviour) or water contact
angle measurements (hydrophobic/hydrophilic character). A quartz crystal monitor has been used to measure water vapour adsorption/desorption
isotherms in the films. From the shape of these isotherms it is possible to estimate the type of pores existing in the different
thin films. Examples of the potential use of these porous thin films as humidity sensors or hydrophilic surfaces are reported. 相似文献