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91.
In this paper, we describe the practical application of a flexibility-based management approach to new product development, highlighting advantages, and limitations of this methodology. The model is concerned with the resolution of uncertainty over the product development life cycle and deals with technical, market, and cost factors all together. To this end, we consider a real options model, which uses multidimensional decision trees, to assess the development process of a high-technology product, namely, the Adaptive Optics Scanning Laser Ophthalmoscope. Moreover, we show how this project could be managed by estimating its value and determining optimal managerial actions to be taken at each review stage of the new product development process. Finally, we draw conclusions about this model's general utility and particular challenges associated with its use as a product development tool, and emphasize the need to consider a multidimensional model, instead of a single dimensional one. 相似文献
92.
J. Marcazzó M. Santiago C. D’Angelo C. Furetta 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2010,268(2):183-186
The photoluminescence (PL), radioluminescence (RL) and thermoluminescence (TL) of KMgF3 doped at several Sm concentrations have been investigated. The maximum TL and RL yield under beta irradiation has been observed in KMgF3:Sm 0.02 mol%. The glow curve of this doped perovskite is made up of at least five peaks located at 95, 120, 160, 270, and 330 °C. The third peak appears to be the most convenient for personal or environmental dosimetry, since it shows no fading and good linearity within the investigated dose range (0.020-200 Gy). From the RL and PL spectra it has been found that most of KMgF3:Sm emission is located at wavelengths higher than 650 nm. This emission, which is characteristic of Sm2+, makes this doped compound attractive for fiber-optic dosimetry. 相似文献
93.
Carlos Sáenz Begoña Hernández Coro Alberdi Santiago Alfonso José Manuel Diñeiro 《European Food Research and Technology》2008,227(5):1329-1338
We have designed a multispectral imaging acquisition system to measure the relative concentration values of myoglobin forms
inside meat during oxygenation. Images at 474, 525, 572 and 610 nm are used to compute the concentration of reduced myoglobin,
oxymyoglobin and metmyoglobin with a spatial resolution of 0.0125 mm/pixel. From these images, pigment concentration profiles
as a function of oxygenation time and depth beneath the surface were obtained. A model describing the diffusion of oxygen
and the consumption of reduced myoglobin is numerically tested versus the measured concentration profiles. The model accurately
fits the data with a Mean Root Squared Error equal to 0.253%. Precise definitions for position and width of pigment layers
based in concentration profiles are given. The results suggest that multispectral imaging techniques combined with precise
control and measurement of sample temperature and oxygen partial pressure will permit detailed studies of the myoglobin chemistry
during oxygenation. 相似文献
94.
95.
Victor Sans Fabien Gelat Naima Karbass M. Isabel Burguete Eduardo García‐Verdugo Santiago V. Luis 《Advanced Synthesis \u0026amp; Catalysis》2010,352(17):3013-3021
Polymer‐supported ionic liquid‐like species (SILLPs) with different functionalities have been combined to obtain new catalytic systems (polymer cocktail) with improved properties towards their application for C C coupling reactions. The SILLPs have been synthesized in a simple way and combined to play different functions in the reaction medium. Those roles involve simultaneously (or consecutively) their actuation as supported reagents, precatalysts and scavengers of undesired reaction side‐products. The system has been tested by employing three different C C coupling reactions for 8 consecutive cycles. Moreover, different aryl bromides and iodides have proved to be efficiently transformed by the catalytic cocktail. Finally, the Heck reaction has been conducted in continuous‐flow conditions using a packed bed of this polymer cocktail and employing supercritical carbon dioxide (scCO2) as a solvent, which cannot be carried out with the use of soluble bases as this would lead to the clogging of the reactor. Finally, the SILLPs cocktail enables one to combine different reaction steps and purification in a single vessel, which represents a significant improvement in terms of process intensification and green chemistry. This is particularly true in the case of the use of scCO2 as this allows the direct production of crude materials not contaminated either by salts or by solvents. 相似文献
96.
Torres E Duque MD Camps P Naesens L Calvet T Font-Bardia M Vázquez S 《ChemMedChem》2010,5(12):2072-2078
The synthesis and antiviral activity of a series of novel polycyclic analogues of the orthopoxvirus egress inhibitor tecovirimat (ST‐246) is presented. Several of these compounds display sub‐micromolar activity against vaccinia virus, and were more potent than cidofovir (CDV). The more active compounds were about 10‐fold more active than CDV, with minimum cytotoxic concentrations above 100 μM . Chemical manipulations of the two carbon–carbon double bonds present in the compounds were carried out to further explore the structure–activity relationships of these new polycyclic imides. Hydrogenation of the two carbon–carbon double bonds decreases antiviral activity, whereas either cyclopropanation or epoxidation of the double bonds fully eliminates the antiviral activity. 相似文献
97.
Effects of two chelating agents (EDTA and DTPA) on the autochthonous vegetation of a soil polluted with Cu, Zn and Cd 总被引:2,自引:0,他引:2
Pastor J Aparicio AM Gutierrez-Maroto A Hernández AJ 《The Science of the total environment》2007,378(1-2):114-118
Chelating agents are thought to be useful for the remediation of metal-polluted soils with adequate organic matter, but the effects of these substances on the plants or seed bank of plant communities that occur in the soils are relatively unknown. In this work, the effects of two chelating substances (EDTA and DTPA) on a wet grassland plant community affected by the presence of the abandoned copper mine "Fernandito" (Garganta de los Montes, Madrid) were compared. A microcosm bioassay (6 months) was designed using the soil's top layer containing the grassland's seed bank. This soil showed a high Cu pollution level, significant contents of Zn and Cd (1120, 190, and 15 ppm, respectively), a pH of 5 and an OM content of 6.2%. The soil was subjected to three different treatments: a) untreated soil (control), b) the addition of 1 g/kg EDTA, or of c) 1 g/kg DTPA. The results presented here are those related to the plant cover, species richness, aboveground and subterranean biomass and chemical composition of the most abundant plants. Neither EDTA nor DTPA caused intense negative effects on the plants rather they significantly increased the amount of copper accumulated in aboveground parts and roots. In particular, Agrostis castellana and Corrigiola telephiifolia extracted high amounts of copper when grown in the soil with added EDTA, although they showed some nutritional imbalances (lower P contents). In contrast, lower metal concentrations were detected in plants grown in the DTPA amended soil. 相似文献
98.
Since the early 1990's, grapefruit juice has been implicated in drug interaction with various furanocoumarins (FCs) now associated with the effect. Although FCs are present in various fruits and vegetables, it is their presence in grapefruit that has attracted the most attention. Studies have shown that FCs in grapefruit juice can vary significantly and from multiple causes. Most of all, FCs are stress-induced molecules, their levels affected by many factors ranging from UV exposure to insect infestation. There are also varietal and seasonal factors. In this study, juice processing and storage parameters were investigated. Prolonged fruit storage prior to processing and most steps involved in juice processing had little influence on the levels of 6',7'-dihydroxybergamottin (DHB), paradisin C, or bergamottin. However, products that were hot filled or stored at room temperature had lower amounts of DHB and paradisin C and higher amounts of bergaptol compared to juices that were not hot filled and stored at refrigerated temperatures. Both DHB and paradisin C are potent CYP3A4 inhibitors, while bergaptol is a very weak inhibitor. Bergamottin amounts decreased to a lesser extent. Therefore, grapefruit juice products that were hot filled or have been stored at room temperature for an extended period of time will have a reduced drug interaction potential. 相似文献
99.
Óscar Rodríguez Jorge Barros-Velázquez Carmen Piñeiro José M. Gallardo Santiago P. Aubourg 《Food chemistry》2006
The application of slurry ice, a binary mixture of small spherical ice crystals surrounded by seawater at subzero temperature, is a potentially new preservation method for farmed turbot (Psetta maxima), a flat fish species of increasing commercial interest. Comparative biochemical, microbiological and sensory analyses were carried on turbot specimens stored in either slurry ice or flake ice for up to 40 days. The results obtained in the sensory analysis correlated well with the observed chemical and microbial changes. Storage of turbot in slurry ice resulted in a slowing-down of the nucleotide degradation pathway and lipid oxidation mechanisms. A good stabilisation of the high molecular weight protein fraction of turbot muscle was also achieved as a consequence of storage in slurry ice. A slower production of both trimethylamine and total volatile bases was also observed. Likewise, low levels of total aerobes, anaerobes, coliforms, and proteolytic bacteria were attained. The application of slurry ice to farmed turbot is advisable to achieve better quality maintenance during storage and distribution. 相似文献
100.
José M. Miranda Jaime Ortiz Jorge Barros-Velázquez Santiago P. Aubourg 《Food and Bioprocess Technology》2016,9(3):387-395
Bifurcaria bifurcata is a widely extended brown macroalga, whose antimicrobial and antioxidant properties have previously been described. In this study, ethanolic extracts of B. bifurcata were included in the icing medium employed for the chilled storage of megrim (Lepidorhombus whiffiagonis). For it, two different concentrations of this brown macroalga extract (0.67 and 2.50 g lyophilized alga L?1 aqueous solution; B-1 and B-2 batches, respectively) were tested for a 14-day storage. The effect of the alga extract was compared with a counterpart batch stored in traditional ice prepared only from water (B-0 batch). Significant (p < 0.05) inhibitions of microbial activity (aerobes, psychrotrophs, lipolytic bacteria, proteolytic bacteria and Enterobacteriaceae) as well as of pH and trimethylamine formation were observed as a result of the incorporation of the alga extract in the icing medium, being this effect especially relevant in the B-2 batch. Concerning lipid damage development, a significantly (p < 0.05) lower formation of free fatty acids (lipid hydrolysis development) and of fluorescent compounds (tertiary lipid oxidation development) in samples corresponding to both alga-including batches could also be observed; this inhibitory effect was more intense in fish belonging to the B-2 batch. The icing medium proposed in this work constitutes a promising strategy in order to apply algae extracts to enhance fish quality retention during the different steps of storage and commercialization of marine species. 相似文献