Effect of thermal annealing on the structural and optical properties of tris‐(8‐hydroxyquinoline)aluminum(III) (Alq3) films

Tris‐(8‐hydroxyquionoline)aluminum (Alq₃) was synthesized and coated on to a glass substrate using the dip coating method. The structural and optical properties of the Alq₃ film after thermal annealing from 50°C to 300°C in 50° steps was studied. The films have been prepared with 2 to 16 layers (42–324 nm). The thickness and thermal annealing of Alq₃ films were optimized for maximum luminescence yield. The Fourier transform infrared spectrum confirms the formation of quinoline with absorption in the region 700 ? 500/cm. Partial sublimation and decomposition of quinoline ion was observed with the Alq₃ films annealed at 300°C. The X‐ray diffraction pattern of the Alq₃ film annealed at 50°C to 150°C reveals the amorphous nature of the films. The Alq₃ film annealed above 150°C were crystalline nature. Film annealed at 150°C exhibits a photoluminescence intensity maximum at 512 nm when excited at 390 nm. The Alq₃ thin film deposited with 10 layers (220 nm) at 150°C exhibited maximum luminescence yield. Copyright © 2014 John Wiley & Sons, Ltd.     

Low‐Temperature Micro‐Solid Oxide Fuel Cells with Partially Amorphous La0.6Sr0.4CoO3‐δ Cathodes

Partially amorphous La_0.6Sr_0.4CoO_3‐δ (LSC) thin‐film cathodes are fabricated using pulsed laser deposition and are integrated in free‐standing micro‐solid oxide fuel cells (micro‐SOFC) with a 3YSZ electrolyte and a Pt anode. A low degree of crystallinity of the LSC layers is achieved by taking advantage of the miniaturization of the cells, which permits low‐temperature operation (300–450 °C). Thermomechanically stable micro‐SOFC are obtained with strongly buckled electrolyte membranes. The nanoporous columnar microstructure of the LSC layers provides a large surface area for oxygen incorporation and is also believed to reduce the amount of stress at the cathode/electrolyte interface. With a high rate of failure‐free micro‐SOFC membranes, it is possible to avoid gas cross‐over and open‐circuit voltages of 1.06 V are attained. First power densities as high as 200–262 mW cm^?2 at 400–450 °C are achieved. The area‐specific resistance of the oxygen reduction reaction is lower than 0.3 Ω cm² at 400 °C around the peak power density. These outstanding findings demonstrate that partially amorphous oxides are promising electrode candidates for the next‐generation of solid oxide fuel cells working at low‐temperatures.     

Differences in phenotypic traits and migratory strategies between eastern North American monarch butterflies,Danaus plexippus (L.)

The eastern North American population of the monarch butterfly (Danaus plexippus plexippus) has different migratory routes. The majority fly to overwintering colonies in Mexico and others take an eastern route through Florida and Cuba. Monarchs migrating through Florida–Cuba do not overwinter and are mostly found nectaring and flying close to vegetation. This present study explores whether Florida–Cuba versus Mexican migrants differ in (1) phenotypic traits important for migration (e.g. wing size and condition, lipid and lean mass content, and reproductive status) and (2) migratory strategies. The monarch natal grounds (e.g. migrants versus residents) were determined through thin‐layer chromatography cardenolide fingerprint and stable isotopes (hydrogen δ²H and carbon δ¹³C). In addition, wing size and condition, lipid and lean mass, and reproductive status were determined. The results suggest that Mexican migrants are better suited for longer sustained flights and successful overwinter periods as a result of larger wings in better condition, reproductive diapause, and significant fat content. By contrast, Florida–Cuba migrants are more suited for shorter flights and opportunistic migratory strategies, given that their wings were in poor condition, as well as the active reproductive status of > 50% of these butterflies and their significantly low fat content. Eastern monarch migration is more complex and diverse than previously assumed. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ?? , ??–??.     

Range edges and the molecular divergence of Greya moth populations

Aim We investigated the geographical pattern of genetic divergence and demographic history in the prodoxid moth Greya obscura throughout its entire geographical range in far western North America and compared it to the geographical patterns found in a previously studied species, Greya politella, which co‐occurs over the same range, in the same habitats, and on the same host plants. Location The study included sites distributed throughout the California Floristic Province. Methods We used analysis of cytochrome c oxidase subunit I (COI) and amplified fragment length polymorphisms to evaluate the pattern and history of genetic continuity among populations. Results Greya obscura populations show a history of spatial expansion with considerable haplotype diversity in the centre of the geographical range. As with G. politella, some range‐edge populations of G. obscura are sufficiently divergent (6.7% in COI) to be considered as potentially cryptic species. Greya obscura and G. politella, however, differ in the specific range‐edge sites showing greatest genetic divergence and cryptic speciation. Main conclusions These results corroborate the view that range edges are important cradles of divergence and speciation. In addition, the results indicate that the geographical pattern of divergence at edges may differ even among closely related species occupying the same habitats and using the same hosts.     

西喜马拉雅地区气候变化与果蝇分布界限的移动(英文)

在长时间尺度上研究环境变化条件下的种群动态,有助于确定不同物种如何对新的生物和非生物条件做出反应。采纳类似的采集方法在相同的地点,分别于1961－1962年和2003－2004年在西喜马拉雅地区对果蝇种类进行了两次野外调查,对两次调查获得的种类的相对丰富度和优势度指数进行了比较。最近50年的气象数据显示西喜马拉雅平均气温（Tave）发生了显著变化,对该地区的果蝇种类组成及分布界限产生了影响。本研究发现在低海拔的地带Drosophila nepalensis及其他一些冷适应种类的数量明显下降;而Drosophila ananassae及其他一些暖适应种类则进入了低海拔和中海拔地带。D. nepalensis的丰富度与所调查地点的平均气温负相关(r = -0.93±0.03),而对于D. ananassaez则是相反趋势(r=0.90±0.05)。据此认为长期（42年）的气候变化已对西喜马拉雅地区的果蝇种类的分布格局产生了影响。     

Growth and Characterization of Epitaxial Insulating CaF2 Layers on Silicon by MBE

In the course of the present work CaF₂ epitaxialfilms were grown on Si(111) substrates by means ofMBE. The Si substrates were chemically cleaned priorto insertion into the system. The final volatile oxidewas desorbed in situ by heating to 850. CaF₂ was evaporated from aKnudsen-type cell by use of a graphite crucible, whilethe growth temperature was held at 650 .RHEED (Reflection High Energy Electron Diffraction)has been used to monitor the film growth in situand to study the epitaxial quality. Also we have usedthe MeV He⁺ RBS channeling technique to look atdefects and to measure strain in the CaF₂ layer.Usually good crystallographic properties are achievedunder optimum growth conditions, with values of_min < 5%. Electrical properties aremeasured by use of a special MIS structure.     

Accessibility of introduced cysteines in chemoreceptor transmembrane helices reveals boundaries interior to bracketing charged residues

Two hydrophobic sequences, 24 and 30 residues long, identify the membrane-spanning segments of chemoreceptor Trg from Escherichia coli. As in other related chemoreceptors, these helical sequences are longer than the minimum necessary for an alpha-helix to span the hydrocarbon region of a biological membrane. Thus, the specific positioning of the segments relative to the hydrophobic part of the membrane cannot be deduced from sequence alone. With the aim of defining the positioning for Trg experimentally, we determined accessibility of a hydrophilic sulfhydryl reagent to cysteines introduced at each position within and immediately outside the two hydrophobic sequences. For both sequences, there was a specific region of uniformly low accessibility, bracketed by regions of substantial accessibility. The two low-accessibility regions were each 19 residues long and were in register in the three-dimensional organization of the transmembrane domain deduced from independent data. None of the four hydrophobic-hydrophilic boundaries for these two membrane-embedded sequences occurred at a charged residue. Instead, they were displaced one to seven residues internal to the charged side chains bracketing the extended hydrophobic sequences. Many hydrophobic sequences, known or predicted to be membrane-spanning, are longer than the minimum necessary helical length, but precise membrane boundaries are known for very few. The cysteine-accessibility approach provides an experimental strategy for determining those boundaries that could be widely applicable.     

Life Cycle costing as part of design for environment environmental business cases

Background  In developing products various requirements have to be integrated including functionality, quality, affordability as well as environmental aspects. Often conflicting requirements have to be fulfilled. Therefore, multi-dimensional decision support approaches are necessary. Methods  Here, one approach is to relate the conflicting requirements to each other. Life Cycle Costing (LCC) has the potential to support the trade-off between some environmental targets and overall affordability targets by including all monetary flows along the product life cycle (going beyond the well-known costs of ownership by integrating also long-term use and end-of-life costs). Those solutions can be identified that (a) have the highest efficiencies (where do we get most environmental improvements per Ϊ and (b) have the highest affordability for the customer along the life cycle. Furthermore, on-costs in the design phase can be justified in terms of future savings either for the customer or for the recycling of the products. These represent real business cases for environmental actions. Three types of environmental business cases can be differentiated. Results and Discussion  This paper presents various examples where LCC is integrated into product design. However, there are a number of open issues in the implementation of LCC within real product development including data availability and uncertainty (future costs/ savings), level of discounting, accounting and compensation. Various internal case studies done in the last years showed that already few changes in the costs structure can significantly affect the identi-fied future costs. Recommendation and Outlook  Uncertainties in LCC are higher than in LCA and highest when applied in the stage of product develop-ment, i.e. used to support DfE action. As a consequence, the result-ing figures can only be seen as directional. Therefore, the use of LCC in Design for Environment cannot be recommended without major restrictions in terms of guidance, experience/training. The link-age between LCC and DfE can either be established via (1) experts supporting design teams or (2) as part of a DfE tool. The DfE tool has to include detailed guidance for interpretation, and its application should be based on a solid training for DfE engineers.     

Rapid regeneration of whole plants in large crabgrass (Digitaria sanguinalis L.) using thin-cell-layer culture

A method was designed to produce rapidly (10–14 days) and directly (without intermediate callus) whole plants of Digitaria sanguinalis with a high yield without subculture. These plants developed from new structures, designated “pseudo-embryogenic structures”, initiated only 1 week after the culture of tranverse thin cell layers (tTCLs), i.e., thin stem sections, on a Murashige and Skoog medium containing 3% sucrose and a combination of a low concentration of 2,4-dichlorophenoxyacetic acid (1 μm) and a high concentration of 6-benzylaminopurine (10 μm). The fresh weight of plants regenerated per tTCL on gelrite was 6 times higher than with agar and 30 times higher than with agarose. Received: 25 August 1997 / Revision received: 18 February 1998 / Accepted: 10 March 1998