Functional foods : a conceptual model for assessing their safety and effectiveness

This report shows that the product-diet dilemma can be solved by developing a predictive model. The model integrates food intake data, dynamic consumption patterns and the production chain model and combines them with a risk-benefit approach

Variation and Distribution of Glucosinolates in 42 Cultivars of Brassica oleracea Vegetable Crops

Brassica vegetables are known to contain glucosinolates that are precursors for bioactive compounds like isothiocyanates that have been shown to play an important role in human health. This study reports the results of a screening of 11 Brassica oleracea crops consisting of 42 cultivars (6 white cabbage, 5 red cabbage, 7 Brussels sprouts, 2 kale, 1 tronchuda, 3 oxheart cabbage, 2 kohlrabi, 6 broccoli, 5 cauliflower, 3 romanesco and 2 Savoy cabbage). All these cultivars were cultivated under the same conditions on a single location in the same season. The variation found in the level of glucosinolates is expected to be mainly due to the genetic variation. A large variation was observed in the level and profile of glucosinolates. Total glucosinolates varied from 14 to 625 µmol/100 g fresh weight. Glucoraphanin, the precursor of the isothiocyanate sulforophane, varied from 0 to 141 µmol/100 g fresh weight. Within broccoli glucoraphanin varied from 27 to 141 µmol/100 g fresh weight. Glucoiberin that is structurally related to glucoraphanin varied from 6 to 397 µmol/100 g fresh weight. Within broccoli glucoiberin varied from 21 to 397 µmol/100 g fresh weigh

Differences in Thermal Stability of Glucosinolates in Five Brassica Vegetables

The thermal stability of individual glucosinolates within five different Brassica vegetables was studied at 100°C for different incubation times up to 120 minutes. Three vegetables that were used in this study were Brassica oleracea (red cabbage, broccoli and Brussels sprouts) and two were Brassica rapa (pak choi and Chinese cabbage). To rule out the influence of enzymatic breakdown, myrosinase was inactivated prior to the thermal treatments. The stability of three glucosinolates that occurred in all five vegetables (gluconapin, glucobrassicin and 4-methoxyglucobrassicin) varied considerably between the different vegetables. The degradation could be modeled by first order kinetics. The rate constants obtained varied between four to twenty fold between the five vegetables. Brussels sprouts showed the highest degradation rates for all three glucosinolates. The two indole glucosinolates were most stable in red cabbage, while gluconapin was most stable in broccoli. These results indicate the possibilities for plant breeding to select for cultivars in which glucosinolates are more stable during processin

Ultrafast all-optical switching by cross phase modulation induced wavelength conversion in silicon-on-insulator waveguides and ring resonators

We present new results on ultrafast alloptical wavelength conversion in Silicon-on-Insulator waveguides through cross phase modulation. We demonstrate sub-picosecond all-optical switching with 13dB on/off ratio by combining the nonlinear wavelength conversion in the port waveguide with passive filtering using an integrated SOI microring resonator.\u

Ultrafast all-optical wavelength conversion in silicon-insulator waveguides by means of cross phase modulation using 300 femtosecond pulses

In this paper we report the ultrafast all-optical wavelength conversion in Silicon-on-Insulator (SOI) waveguides. We used a pump-probe setup with 300 femtosecond pulses to demonstrate large temporal phase-shifts, caused by the Kerr effect and free carrier generation. Large wavelength shifts of a 1683nm probe signal have been observed. The wavelength conversion, ranging from 10nm redshifts to 15nm blueshifts, depending on the time delay between the pump and probe pulses, is caused by the pump induced Cross Phase Modulation. Furthermore, an all-optical switching scheme using SOI microring resonators is discussed. These results enable ultrafast all-optical switching using SOI microring resonators

End-of-Life Inventory Decisions for Consumer Electronics Service Parts

We consider a consumer electronics (CE) manufacturer’s problem of controlling the inventoryof spare parts in the final phase of the service life cycle. The final phase starts when thepart production is terminated and continues until the last service contract or warranty periodexpires. Placing final orders for service parts is considered to be a popular tactic to satisfy demandduring this period and to mitigate the effect of part obsolescence at the end of the servicelife cycle. To satisfy demand for service in the final phase, previous research focuses on repairingdefective products by replacing the defective parts with properly functioning spare ones.However, for consumer electronic products there is a remarkable price erosion while repaircosts may stay steady over time. As a consequence, this introduces the idea that there mightbe a point in time at which the unit price of the product is lower than repair associated costs.Therefore, it would be more cost effective to adopt an alternative policy to meet demands forservice such as offering customers a replacement of the defective product with a new one orgiving a discount on the next generation of the product. This paper examines the cost trade-offsof implementing alternative policies for the repair policy and develops an exact formulation forthe expected total cost function. Based on this developed cost function we propose policies tosimultaneously find the optimal final order quantity and the time to switch from the repair toan alternative replacement policy. Numerical analysis of a real world case study sheds lightover the effectiveness and advantage of these policies in terms of cost reduction and also yieldsinsights into the quantitative importance of the various cost parameters.consumer electronics;end-of-life inventory control;service parts

Verjonging in douglasbos neigt weer naar douglas

Het Nederlandse bos is nog steeds voor het grootste deel gelijkjarig en weinig gemengd, zo blijkt uit metingen over de periode 2001-2005 van het Meetnet Functievervulling Bos. Bosbeleid en -beheer zijn er al decennialang op gericht om de voormalige plantagebossen op een natuurgerichte wijze om te vormen en te beheren. In het bos kom je dan ook veel natuurlijke verjonging tegen die opkomt op plaatsen waar flinke gaten in het kronendak zijn gemaakt. Verjonging die vaak mooi gemengd is. De natuur doet zijn werk na een initiële beheersmaatregel; doel bereikt dus? Uit metingen aan verjongingen in een douglasmonoculture blijkt dat in eerste instantie berk, lariks en douglasspar het goed doen, en dat grove den het van het begin af moeilijk heeft. Op langere termijn neigt deze verjonging echter weer naar douglas, tenzij flink en vaak ingegrepen wordt