Flow cytometric,chromosomal and morphometric analyses challenge current taxonomic concepts in the Portulaca oleracea complex (Portulacaeae,Caryophyllales)

Portulaca oleracea is a noxious annual weed of worldwide distribution in temperate to tropical climates. Its taxonomy has been treated in contradictory ways in the past. Various microspecies have been described, lumped into a single species by other authors. We re‐examined the importance of seed size and ploidy variation, previously applied as the most important taxonomic characters, for systematic classification based on accessions from Europe, Asia, Africa and South America using flow cytometry, chromosome counting and morphometry. Sixteen microspecies and six transitional forms, covering the ploidy and seed character variation, proposed for the complex, were studied from 178 populations. Portulaca grandiflora was included as a reference species from outside the complex. DNA hyper‐pentaploidy or hexaploidy were inferred for the majority of accessions which exhibited the full range of seed size. It is recommended that the only species of lower ploidy (either diploid based on x = 12 or tetraploid based on x = 12) encountered, P. nicaraguensis, should be separated from the P. oleracea complex as it deviates in base chromosome number and monoploid genome size. The frequency distribution of seed size was continuous and unimodal within the wild taxa of the complex and in pairs of taxa defined by testa sculpture. Seed size of DNA hexaploids was slightly negatively correlated with sample/standard fluorescence intensities. Our results conflict with the current microspecies concept. Possible reasons underlying the discrepancy are discussed and strategies for future systematic research are suggested. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 144–156.     

Modification of Emission Properties of ZnO Layers due to Plasmonic Near-Field Coupling to Ag Nanoislands

A simple fabrication method of silver (Ag) nanoislands on ZnO films is presented. Continuous wave and time-resolved photoluminescence and transmission are employed to investigate modifications of visible and UV emissions of ZnO brought about by coupling to localized surface plasmons residing on Ag nanoislands. The size of the nanoislands, determining their absorption and scattering efficiencies, is found to be an important factor governing plasmonic modification of optical response of ZnO films. The presence of the Ag nanoislands of appropriate dimensions causes a strong (threefold) increase in emission intensity and up to 1.5 times faster recombination. The experimental results are successfully described by model calculations within the Mie theory.     

Structural Properties of the Human Protease-Activated Receptor 1 Changing by a Strong Antagonist

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Building and deploying a cyberinfrastructure for the data-driven design of chemical systems and the exploration of chemical space

Abstract

The use of modern data science has recently emerged as a promising new path to tackling the complex challenges involved in the creation of next-generation chemistry and materials. However, despite the appeal of this potentially transformative development, the chemistry community has yet to incorporate it as a central tool in every-day work. Our research program is designed to enable and advance this emerging research approach. It is centred around the creation of a software ecosystem that brings together physics-based modelling, high-throughput in silico screening and data analytics (i.e. the use of machine learning and informatics for the validation, mining and modelling of chemical data). This cyberinfrastructure is devised to offer a comprehensive set of data science techniques and tools as well as a general-purpose scope to make it as versatile and widely applicable as possible. It also emphasises user-friendliness to make it accessible to the community at large. It thus provides the means for the large-scale exploration of chemical space and for a better understanding of the hidden mechanisms that determine the properties of complex chemical systems. Such insights can dramatically accelerate, streamline and ultimately transform the way chemical research is conducted. Aside from serving as a production-level tool, our cyberinfrastructure is also designed to facilitate and assess methodological innovation. Both the software and method development work are driven by concrete molecular design problems, which also allow us to assess the efficacy of the overall cyberinfrastructure.     

Comparative life cycle assessment of electric motors with different efficiency classes: a deep dive into the trade-offs between the life cycle stages in ecodesign context

Purpose

Current ecodesign instruments usually focus on improving single life cycle stages, like the energy efficiency classes for motors put on the European market, which focus on the use stage. Resulting trade-offs between the life cycle stages are however often not integrated properly, like for instance trade-offs between manufacturing stage and use stage. The goal of this study was to evaluate the trade-offs between the additional efforts of producing energy-efficient motors (achieved, e.g., via different materials for certain components) and the advantages gained from the improved efficiency in operation.

Methods

For this case study, a life cycle assessment methodology according to ISO 14040/44 was applied for the whole life cycle (cradle to grave) of three electric motors, each from a different efficiency class, and one serving as baseline. The motors under study have the following specifications in common: asynchronous technology, 110 kW nominal power, cast iron series, and 4-poles. To evaluate the use stage, two different operational profiles were studied for 20 years’ service life.

Results and discussion

The results clearly indicated the dominance of the use stage in the motors’ life cycles and that an increase in efficiency pays off environmentally within the first month of operation in the applied load-time profiles. The dominating environmental impact categories, like ionizing radiation and global warming potential, relate to the consumption of electricity. The study results indicated also that the increase of the analyzed motors’ efficiency encompasses trade-offs between the stages materials, manufacturing, and end-of-life versus the use stage in regard to toxicity and (metal) resource depletion aspects, i.e., a burden shifting between energy-related impacts and the toxicity- and resource depletion-related impacts.

Conclusions

In the analyzed study set-ups, including the modeled energy generation scenarios for Europe in 2050, an environmental break-even is achieved in less than a month in all impact categories except for human toxicity. Thus, the further improvement of energy efficiency of drive systems is and will stay a central ecodesign lever. However, toxicity and resource depletion trade-offs should be considered carefully within decision support and decision-making, and further research on related characterization models is necessary. Further, it is concluded that the load-time profile as well as the motors’ service life have a high influence, and therefore, designing drive systems in context with the application seems to be an important approach to facilitate ecodesign.