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排序方式: 共有176条查询结果,搜索用时 15 毫秒
1.
Evaluation of the effect of processing on cocoa polyphenols: antiradical activity,anthocyanins and procyanidins profiling from raw beans to chocolate 下载免费PDF全文
Matteo Bordiga Monica Locatelli Fabiano Travaglia Jean Daniel Coïsson Giuseppe Mazza Marco Arlorio 《International Journal of Food Science & Technology》2015,50(3):840-848
The content and composition of anthocyanins and procyanidins in fermented cocoa beans (from different geographic origins: Ecuador, Cameroon, Ivory Coast, Ghana and Nigeria), roasted nibs, cocoa mass and chocolate were determined, beside the determination of the total antiradical capacity. Concerning geographic origin, cocoa beans and processed products from Ecuador showed the highest levels of anthocyanins, followed by Nigeria and Cameroon. Generally, as cocoa beans were further processed, the levels of anthocyanins and flavan‐3‐ols decreased. The largest observed losses of phenolics occurred during roasting. A progressive decreasing trend in polyphenol concentration was observed in the other processed samples as well. Despite the original content of polyphenols in raw cocoa beans, technological processes imply a significant impact on cocoa quality, confirming the need of specific optimisation to obtain high value chocolate. 相似文献
2.
In this work it is presented a study on the residence time distribution (RTD) of particles in a co-current pilot-plant spray dryer operated with a rotary atomization system. A nuclear technique is applied to investigate the RTD responses of spray dryers. The methodology is based on the injection of a radioisotope tracer in the feed stream followed by the monitoring of its concentration at the outlet stream. The experiments were performed during the drying of aqueous suspensions of gadolinium oxide. The RTD responses obtained experimentally presented good reproducibility, indicating that the technique applied is well suited to investigating fluid-dynamics of spray dryers. In addition to the experimental investigation, a mathematical model was used to describe the RTD experimental curves. 相似文献
3.
A.G. Berkovski G. Chiodi J.-P. Fabre A. Frenkel S.V. Golovkin Yu.I. Gubanov G.N. Kislizkai E.N. Kozarenko I.E. Kreslo A.E. Kushnirenko G. Martellotti D. Mazza A.M. Medvedkov G. Penso 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1996,380(3):537-543
We present the performance of a high-speed gateable vacuum image pipeline, which permits individual images to be delayed and selected from continuous non-repetitive image stream. This device is composed of a vacuum tube equipped with a photocathode at one end, a phosphor screen at the other end, and a system of metal grids in between. Photoelectrons produced by the images focused on the photocathode, are guided by a uniform magnetic field, parallel to the tube axis. By changing the grid potentials, the drift time of the photoelectrons inside the tube can be varied from 0.35 to 1.5 μs. An image can then be selected by an external trigger with a time resolution in the range of 4–30 ns, depending on the delay time. The selected photoelectrons are finally accelerated onto the phosphor screen, set at 10 kV, where they reproduce the desired image. With a magnetic field of 0.1 T, a spatial resolution of 33 lp/mm was obtained. The high spatial and time resolution make this device an interesting tool for high-energy physics and astrophysics experiments, and for high-speed photography. 相似文献
4.
BACKGROUND: The incidental discovery of an adrenal mass poses the problem of distinguishing between the frequent benign masses and the infrequent malignant ones that require surgery. Univocal guidelines to approach this problem are unavailable. OBJECTIVE: To perform a survey of the clinical management of incidentally discovered adrenal masses (ie, adrenal incidentalomas). DESIGN: A multicentric retrospective analysis of hospital medical records of adrenal incidentalomas diagnosed during a 5-year period; the medical records were scrutinized for demographic data and clinical details by means of a specifically tailored questionnaire. SETTING: The major surgical and medical centers of Piedmont, a northern Italian region with approximately 4 million inhabitants. The recruitment pattern of these centers was unselected. PATIENTS: The definition of adrenal incidentaloma was limited to patients with a physical examination and a clinical history unindicative of adrenal disease. Exclusion criteria also included hypertension of suspected endocrine origin and a history of neoplasms known to metastasize frequently in the adrenal glands. Two hundred twenty-four medical records were collected, and 210 were analyzed (14 excluded a posteriori). RESULTS: Most patients were in their 50s and 60s, and women were predominantly affected. The frequency of adrenocortical cancer was 13% among patients operated on. The tumor diameter was highly correlated with the risk of cancer; a cutoff at 5 cm had a sensitivity of 93% with a specificity of 64% in discriminating between benign and malignant cortical lesions. CONCLUSIONS: The occurrence of adrenocortical carcinoma among adrenal incidentalomas is not rare. The evaluation of the mass size is a simple and effective method for selecting patients at risk for cancer. The indication for surgery of masses larger than 5 cm, or of masses of any diameter that have suspicious imaging characteristics, limits unnecessary operations and costs. 相似文献
5.
Community violence has emerged as a major risk factor for the development of mental health problems in children and adolescents. If mental health providers are to meet the needs of children and communities dealing with community violence, then they will need to integrate principles from various subdisciplines in psychology (e.g., developmental psychology, school psychology, developmental psychopathology) as well as disciplines outside of psychology (e.g., sociology, public health, medicine) to understand fully the developmental impact of exposure to community violence. The development of such a model is necessary to identify the pathways, risk, and protective factors on which prevention and intervention programs can be built. The goal of this article is to present an ecological-transactional model of community violence as a conceptual framework for understanding the existing literature and for guiding future research on community violence exposure and child development. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
6.
The present research was focused on the development of a new glass to produce glass–alumina FGMs. The glass formulation, belonging to the CaO–ZrO2–SiO2 system, was doped with cobalt, by adding a small molar percentage (about 0.1 mol%) of CoO, in order to obtain a blue glass, which could be useful to appreciate the final compositional gradient. The glass was accurately characterized, evaluating its thermal behaviour, its mechanical properties, and its attitude to crystallize during a thermal treatment. Subsequently, the glass was used to produce glass–alumina FGMs via percolation and the so obtained specimens were analysed in order to evaluate the effect of the glass infiltration. The possible development of new crystal phases, in particular, was tested via micro X-ray diffraction and the elastic properties gradient associated with the compositional gradient was measured via depth-sensing Vickers microindentation. 相似文献
7.
S.R. Holdsworth E. Mazza L. Binda L. Ripamonti 《Nuclear Engineering and Design》2007,237(24):2292-2301
Crack initiation endurances have been determined for a 1CrMoV rotor steel in uniaxial service cycle thermo-mechanical fatigue (TMF) tests formulated to simulate a range of steam turbine start cycles with a maximum temperature of 565 °C. The experimental details for these TMF tests are described.Post test inspection has been employed to characterise the associated thermal fatigue damage mechanisms for the steel which are observed to be dependent on the magnitude of the thermal transient in the TMF cycle.The lowest resistance to thermal fatigue damage development occurs in these tests when the conditions determine that the rate of creep damage accumulation below the surface exceeds the rate of fatigue crack development at the surface. 相似文献
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9.
A. Cigada B. Mazza P. Pedeferri G. Salvago D. Sinigaglia G. Zanini 《Corrosion Science》1982,22(6):559-578
Stress corrosion cracking (SCC) of AISI 304L and AISI 316L stainless steels, cold-worked under various conditions (i.e. at different degrees of deformation obtained by drawing and rolling at room temperature and at liquid nitrogen temperature) has been carried out in H2O containing 1000 ppm Cl? at 250°C and in a boiling MgCl2 solution. The effect of heat treatments at 400 and 900°C on the SCC of previously cold-worked steels has also been studied. Particular attention was directed towards heat treatment at 400°C. In steels deformed at room temperature, it increases the SCC resistance. By contrast, for steels deformed at liquid nitrogen temperature, heat treatment at 400°C reduces the SCC resistance if carried out for short periods of time (1–6 h). Hardness measurements, structural analyses via X-rays, scanning and transmission electron microscopy (SEM and TEM), as well as modified Strauss tests, seem to prove that reduced stress corrosion resistance is not to be related to the chromium-rich carbides precipitation which could have been accelerated by the presence of α′-martensite. Instead, they tend to suggest that perhaps this phenomenon is connected to an increase in the level of internal micro-stresses which are generated by a reciprocal re-ordering of the α′ and γ structural phases. 相似文献
10.