The response of Plantago major ssp pleiosperma to elevated CO2 is modulated by the formation of secondary shoots

The effect of elevated CO2 on the relative growth rate (RGR) of Plantago major ssp. pleiosperma was studied during the vegetative stage, in relation to plant development, by growing plants at 350 mu l l(-1) or at 700 mu l l(-1) CO2 in non-limiting nutrient solution with nitrate. To minimize interference by the accumulation of non-structural carbohydrates in the interpretation of results, RGR was expressed on a f. wt basis (RGR(FW)), as were all plant weight ratios. Stimulation of the RGR(FW) Of the whole plant by elevated CO2 was transient, and did not last longer than 8 d. At the same time a transient increase in root weight ratio (RWR) was observed. In order to investigate whether the transient effect of elevated CO2 on RGR(FW) was size-dependent, the data were plotted versus total f. wt (log(e) transformed). The transient period of stimulation of RGR(FW) and of RWR by elevated CO2 was still found, but in both CO2 treatments RGR(FW) decreased after a certain plant size had been reached. This size coincided with the stage at which secondary shoots started to develop, and was reached earlier in plants grown at elevated CO2. The RGR of these secondary shoots (RGR(see)) was Still increased when the period of whole plant stimulation of RGR(FW) had ended, indicating that the development of these new sinks took priority over a continuation of the stimulation of RWR. It is hypothesized that in this Plantago subspecies the response of the RGR(FW) of the whole plants to elevated CO2 is modulated by the formation of secondary shoots. Apparently, partitioning of the extra soluble carbohydrates at elevated CO2 to this tissue takes precedence over partitioning to the roots. resulting in a cessation of stimulation of plant RGR(FW) by elevated CO2.info:eu-repo/semantics/publishedVersio

First lithographic results from the extreme ultraviolet Engineering Test Stand

The extreme ultraviolet ͑EUV͒ Engineering Test Stand ͑ETS͒ is a step-and-scan lithography tool that operates at a wavelength of 13.4 nm. It has been developed to demonstrate full-field EUV imaging and acquire system learning for equipment manufacturers to develop commercial tools. The initial integration of the tool is being carried out using a developmental set of projection optics, while a second, higher-quality, projection optics is being assembled and characterized in a parallel effort. We present here the first lithographic results from the ETS, which include both static and scanned resist images of 100 nm dense and isolated features throughout the ring field of the projection optics. Accurate lithographic models have been developed and compared with the experimental results

Membrainy: a ‘smart’, unified membrane analysis tool

BACKGROUND: The study of biological membranes using Molecular Dynamics has become an increasingly popular means by which to investigate the interactions of proteins, peptides and potentials with lipid bilayers. These interactions often result in changes to the properties of the lipids which can modify the behaviour of the membrane. Membrainy is a unified membrane analysis tool that contains a broad spectrum of analytical techniques to enable: measurement of acyl chain order parameters; presentation of 2D surface and thickness maps; determination of lateral and axial headgroup orientations; measurement of bilayer and leaflet thickness; analysis of the annular shell surrounding membrane-embedded objects; quantification of gel percentage; time evolution of the transmembrane voltage; area per lipid calculations; and quantification of lipid mixing/demixing entropy. RESULTS: Each analytical component within Membrainy has been tested on a variety of lipid bilayer systems and was found to be either comparable to or an improvement upon existing software. For the analytical techniques that have no direct comparable software, our results were confirmed with experimental data. CONCLUSIONS: Membrainy is a user-friendly, intelligent membrane analysis tool that automatically interprets a variety of input formats and force fields, is compatible with both single and double bilayers, and capable of handling asymmetric bilayers and lipid flip-flopping. Membrainy has been designed for ease of use, requiring no installation or configuration and minimal user-input to operate

ELECTRIC-FIELD EFFECTS ON LIPID-MEMBRANE STRUCTURE

Multiple bilayers of dimyristoyl phosphatidylcholine and potassium oleate were macroscopically oriented between silver-coated glass slides. These model membranes were subjected to an electric field of up to 105V · cm−1. The influence of the field on the molecular structure was monitored by ESR of cholestane and stearic acid spin labels and by NMR of the phosphorus atom in the phosphatidylcholine headgroup.It is concluded that the conformation of the headgroup is greatly affected while no influence on the structure and dynamics of the hydrocarbon chains can be detected. At electric fields above 104 V · cm−1, where structural effects are still reversible, spontaneous current fluctuations are observed. At fields above 105 V · cm−1, irreversible breakdown of the bilayer structure occurs