Experimental Determination of the Lorenz Number in Cu0.01Bi2Te2.7Se0.3 and Bi0.88Sb0.12

Nanostructuring has been shown to be an effective approach to reduce the lattice thermal conductivity and improve the thermoelectric figure of merit. Because the experimentally measured thermal conductivity includes contributions from both carriers and phonons, separating out the phonon contribution has been difficult and is mostly based on estimating the electronic contributions using the Wiedemann-Franz law. In this paper, an experimental method to directly measure electronic contributions to the thermal conductivity is presented and applied to Cu0.01Bi2Te2.7Se0.3, [Cu0.01Bi2Te2.7Se0.3]0.98Ni0.02, and Bi0.88Sb0.12. By measuring the thermal conductivity under magnetic field, electronic contributions to thermal conductivity can be extracted, leading to knowledge of the Lorenz number in thermoelectric materials

Expression of human interferon gamma in Brassica napus seeds

Expressions of heterologous proteins in suitable plant tissues and targeting it into subcellular compartments using specific signals have been studied. Seed-based platforms are among those that allow recombinant proteins to stably accumulate at a relatively high concentration in a compact biomass. In this study, we used seed specific promoter (Napin) and C-terminal KDEL sequence to express human therapeutic protein, interferon gamma (IFN_y) in Brassica napus seeds. Kozak sequence was linked to the 5' end of the IFN_y gene to increase the level of expression. The constructed cassette was transformed into rapeseed. Presence and expression of the transgene were confirmed in the transformants by polymerase chain reaction (PCR) and sodium dodecylsulfatepolyacrylamide gel electrophoresis (SDS-PAGE). Analysis of transgenic plants by enzyme-linked immunosorbent assay (ELISA), dot blot and western blot indicated that IFN_y protein is being expressed in B. napus seeds and is as active as the standard IFN_y. Our results indicate that plant seeds have tremendous potential for production of recombinant proteins as ‘natural bioreactors’.Key words: Interferon gamma, KDEL retention signal, seed specific promoter, Brassica napus, recombinant proteins

An electrochemical system for efficiently harvesting low-grade heat energy

Efficient and low-cost thermal energy-harvesting systems are needed to utilize the tremendous low-grade heat sources. Although thermoelectric devices are attractive, its efficiency is limited by the relatively low figure-of-merit and low-temperature differential. An alternative approach is to explore thermodynamic cycles. Thermogalvanic effect, the dependence of electrode potential on temperature, can construct such cycles. In one cycle, an electrochemical cell is charged at a temperature and then discharged at a different temperature with higher cell voltage, thereby converting heat to electricity. Here we report an electrochemical system using a copper hexacyanoferrate cathode and a Cu/Cu2+ anode to convert heat into electricity. The electrode materials have low polarization, high charge capacity, moderate temperature coefficients and low specific heat. These features lead to a high heat-to-electricity energy conversion efficiency of 5.7% when cycled between 10 and 60 degrees C, opening a promising way to utilize low-grade heat.open121

Indirect shoot regeneration of Iranian purple coneflower (Echinacea purpurea L.) from cotyledon and hypocotyl explants

In vitro plant regeneration was optimized for Iranian purple coneflower via organogenesis from callus cultures derived from cotyledon and hypocotyl tissues by placing them on MS medium supplemented with different concentrations and combinations of BAP and NAA. The experiment was laid out as a completely randomized design in a factorial arrangement with three replications. The results indicated that the mean callus induction was influenced by explant type, with a significant difference between cotyledon (77.81%) and hypocotyl (65.33%) explants at the 0.01 probability level. In relation with the regeneration rate, no significant differences were observed between the two types of explants. For both cotyledons and hypocotyls the optimum shoot regeneration frequency (31.5% and 32.5%, respectively) and number of shoots per explant (5.2 and 5.3, respectively) were achieved using medium supplemented with 0.4 mg l−1 BAP. Proliferated shoots were elongated in hormone-free MS medium and well-developed shoots were rooted on MS medium, both with and without the addition of 2 mg l−1 IBA. All the plantlets survived acclimatization, producing normal plants under controlled conditions. This study revealed that cotyledon and hypocotyl explants of E. purpurea have relatively good potential for callus induction and shoot formation. Furthermore, a beneficial method has been established for the micropropagation of this valuable medicinal species.</jats:p