Identifying the transporters of different flavonoids in plants

We recently identified a new component of flavonoid transport pathways in Arabidopsis. The MATE protein FFT (Flower Flavonoid Transporter) is primarily found in guard cells and seedling roots, and mutation of the transporter results in floral and growth phenotypes. The nature of FFT’s substrate requires further exploration but our data suggest that it is a kaempferol diglucoside. Here we discuss potential partner H+-ATPases and possible redundancy among the close homologues within the large Arabidopsis MATE family

Extended x-ray absorption fine structure study of porous GaSb formed by ion implantation

Porous GaSb has been formed by Ga ion implantation into crystalline GaSb substrates at either room temperature or −180 °C. The morphology has been characterized using scanning electron microscopy and the atomic structure was determined using extended x-ray absorption fine structure spectroscopy. Room-temperature implantation at low fluences leads to the formation of ∼20-nm voids though the material remains crystalline. Higher fluences cause the microstructure to evolve into a network of amorphous GaSb rods ∼15 nm in diameter. In contrast, implantation at −180 °C generates large, elongated voids but no rods. Upon exposure to air, the surface of the porous material is readily oxidized yielding Ga₂O₃ and metallic Sb precipitates, the latter resulting from the reduction of unstable Sb₂O₃. We consider and discuss the atomic-scale mechanisms potentially operative during the concurrent crystalline-to-amorphous and continuous-to-porous transformations

Novel thermal management of power electronic devices: high power high frequency planar gunn diodes

Thermal management of next generation of semiconductor devices is becoming more challenging, as the device power increases and device dimensions decrease. The work is addressing novel thermal measurement and management for planar heterostructure Gunn diodes, which will be of strategic importance for UK technology and industry

Power grids vulnerability: a complex network approach

Power grids exhibit patterns of reaction to outages similar to complex networks. Blackout sequences follow power laws, as complex systems operating near a critical point. Here, the tolerance of electric power grids to both accidental and malicious outages is analyzed in the framework of complex network theory. In particular, the quantity known as efficiency is modified by introducing a new concept of distance between nodes. As a result, a new parameter called net-ability is proposed to evaluate the performance of power grids. A comparison between efficiency and net-ability is provided by estimating the vulnerability of sample networks, in terms of both the metrics.Comment: 16 pages, 3 figures. Figure 2 and table II modified. Typos corrected. Version accepted for publication in Chao

How the First Stars Regulated Star Formation. II. Enrichment by Nearby Supernovae

Metals from Population III (Pop III) supernovae led to the formation of less massive Pop II stars in the early universe, altering the course of evolution of primeval galaxies and cosmological reionization. There are a variety of scenarios in which heavy elements from the first supernovae were taken up into second-generation stars, but cosmological simulations only model them on the largest scales. We present small-scale, high-resolution simulations of the chemical enrichment of a primordial halo by a nearby supernova after partial evaporation by the progenitor star. We find that ejecta from the explosion crash into and mix violently with ablative flows driven off the halo by the star, creating dense, enriched clumps capable of collapsing into Pop II stars. Metals may mix less efficiently with the partially exposed core of the halo, so it might form either Pop III or Pop II stars. Both Pop II and III stars may thus form after the collision if the ejecta do not strip all the gas from the halo. The partial evaporation of the halo prior to the explosion is crucial to its later enrichment by the supernova.Comment: Accepted to Ap

The influence of pigmentation patterning on bumblebee foraging from flowers of <em>Antirrhinum majus</em>

Patterns of pigmentation overlying the petal vasculature are common in flowering plants and have been postulated to play a role in pollinator attraction. Previous studies report that such venation patterning is significantly more attractive to bee foragers in the field than ivory or white flowers without veins. To dissect the ways in which venation patterning of pigment can influence bumblebee behaviour, we investigated the response of flower-naïve individuals of Bombus terrestris to veined, ivory and red near-isogenic lines of Antirrhinum majus. We find that red venation shifts flower colour slightly, although the ivory background is the dominant colour. Bees were readily able to discriminate between ivory and veined flowers under differential conditioning but showed no innate preference when presented with a free choice of rewarding ivory and veined flowers. In contrast, both ivory and veined flowers were selected significantly more often than were red flowers. We conclude that advantages conferred by venation patterning might stem from bees learning of their use as nectar guides, rather than from any innate preference for striped flowers. © 2013 Springer-Verlag Berlin Heidelberg

Contribution of Scalar Loops to the Three-Photon Decay of the Z

I corrected 3 mistakes from the first version: that were an omitted Feynman integration in the function f^3_{ij}, a factor of 2 in front of log f^3_{ij} in eq.2 and an overall factor of 2 in Fig.1 c). The final result is changed drastically. Doing an expansion in the Higgs mass I show that the matrix element is identically 0 in the order (MZ/MH)^2, which is due to gauge invariance. Left with an amplitude of the order (MZ/MH)^4 the final result is that the scalar contribution to this decay rate is several orders of magnitude smaller than those of the W boson and fermions.Comment: 6 pages, plain Tex, 1 figure available under request via fax or mail, OCIP/C-93-5, UQAM-PHE-93/0

Performance and Acceptability of Legume-Fortified Yam Flours

Yam (Dioscoreasp.) is an annual climbing plant with edible underground tubers which is a major staple of many African and Asian countries. About 52 million tonnes of yam was produced globally in 2007, with 96% from West African (IITA, 2009). Yam has the highest calories provided per hectare when compared with other starchy tubers such as cassava and potatoes. Yam is rich in carbohydrates, dietary fibre and some minerals. Yams are usually consumed boiled, roasted, fried or pounded. The tubers are stored in-between harvests for later use which is characterized by changes in wholesomeness which may result from poor handling, wound repair, diseases, and pests infestations. Also due to its high moisture content (50- 80%), large size, and high respiration rates, it is highly perishable. Hence yam tubers are lost after 4-5 months of storage, thus causing a yearly cycle of huge post- harvest losses. In Ghana, post- harvest losses of yam have been reported to range from 10% to 50%. Although West Africa produces about 94% of the world’s yam, yams have not been processed to any significant extent commercially. However due to similarity in composition of yam to crops like potato,yams could be processed into ready to eat foods like chips, crisps flakes and fries to increase their commercial value. They can also be processed into flours for instant foods (e.g. porridge, fufu, mpotonpoton (yam porridge that is spiced with palm oil added)). Fortifying yam flours with legumes such as soyabean and cowpeas could further enhance their commercial value as the fortified products could be used for complementary feeding. This study therefore developed legume-fortified yam flours to enhance their nutritional level as well as extend the shelf-life of yam. The results showed that the blends were acceptable to trained sensory panellists at baseline and also at six months. The products were also nutritionally enhanced, and could therefore be used for complementary feeding. Keywords:Yams, Post-harvest Losses, Value-addition, Legume-fortified flour

Micro-cooler Enhancements by Barrier Interface Analysis

Peer reviewedPublisher PD