149 research outputs found
Enhancement of biomass production, salinity tolerance and nutraceutical content of spinach (Spinacia oleracea L.) with the cuticular wax constituent triacontanol
The present study investigates the effect of foliar application of triacontanol (TRIA) on various physiological parameters with regard to crop yield and quality attributes of spinach (Spinacia oleracea L.) under normal growth conditions and salinity stress. Plantlets were grown for 21 days in perlite-containing pots supplemented with Hoagland’s nutrient solution, then they were subjected to 0 (control) or 150 mM NaCl. Two concentrations of TRIA (25 nM and 1 μM) were applied during seed germination and as foliar spray treatment, in itself or simultaneously with salt stress at 4-day intervals for three weeks. Exogenous application of TRIA enhanced germination energy and capacity, as well as shoot and root biomass of young spinach plants. Inhibition of net CO2 assimilation (Pn) and of potential quantum yield of photosystem II (Fv/Fm), caused by salt stress, was significantly reduced by treatment with triacontanol. Increment of carotenoid pigment and ascorbate (vitamin C) content, as well as reduction of membrane lipid peroxidation due to triacontanol treatment improves the health-promoting quality of spinach leaves developed under high salinity conditions. The presented results offer a novel solution for optimization of spinach cultivation on soils affected by high salinity, as well as for an increased content of health-promoting metabolites of spinach leaves upon human consumption
Identifying super-feminine, super-masculine and sex-defining connections in the human braingraph
For more than a decade now, we can discover and study thousands of cerebral connections with the application of diffusion magnetic resonance imaging (dMRI) techniques and the accompanying algorithmic workflow. While numerous connectomical results were published enlightening the relation between the braingraph and certain biological, medical, and psychological properties, it is still a great challenge to identify a small number of brain connections closely related to those conditions. In the present contribution, by applying the 1200 Subjects Release of the Human Connectome Project (HCP) and Support Vector Machines, we identify just 102 connections out of the total number of 1950 connections in the 83-vertex graphs of 1064 subjects, which-by a simple linear test-precisely, without any error determine the sex of the subject. Next, we re-scaled the weights of the edges-corresponding to the discovered fibers-to be between 0 and 1, and, very surprisingly, we were able to identify two graph edges out of these 102, such that, if their weights are both 1, then the connectome always belongs to a female subject, independently of the other edges. Similarly, we have identified 3 edges from these 102, whose weights, if two of them are 1 and one is 0, imply that the graph belongs to a male subject-again, independently of the other edges. We call the former 2 edges superfeminine and the first two of the 3 edges supermasculine edges of the human connectome. Even more interestingly, the edge, connecting the right Pars Triangularis and the right Superior Parietal areas, is one of the 2 superfeminine edges, and it is also the third edge, accompanying the two supermasculine connections if its weight is 0; therefore, it is also a "switching" edge. Identifying such edge-sets of distinction is the unprecedented result of this work
Grain coarsening in two-dimensional phase-field models with an orientation field
In the literature, contradictory results have been published regarding the
form of the limiting (long-time) grain size distribution (LGSD) that
characterizes the late stage grain coarsening in two-dimensional and
quasi-two-dimensional polycrystalline systems. While experiments and the
phase-field crystal (PFC) model (a simple dynamical density functional theory)
indicate a lognormal distribution, other works including theoretical studies
based on conventional phase-field simulations that rely on coarse grained
fields, like the multi-phase-field (MPF) and orientation field (OF) models,
yield significantly different distributions. In a recent work, we have shown
that the coarse grained phase-field models (whether MPF or OF) yield very
similar limiting size distributions that seem to differ from the theoretical
predictions. Herein, we revisit this problem, and demonstrate in the case of OF
models [by R. Kobayashi et al., Physica D 140, 141 (2000) and H. Henry et al.
Phys. Rev. B 86, 054117 (2012)] that an insufficient resolution of the small
angle grain boundaries leads to a lognormal distribution close to those seen in
the experiments and the molecular scale PFC simulations. Our work indicates,
furthermore, that the LGSD is critically sensitive to the details of the
evaluation process, and raises the possibility that the differences among the
LGSD results from different sources may originate from differences in the
detection of small angle grain boundaries
Room temperature manipulation of long lifetime spins in metallic-like carbon nanospheres
The time-window for processing electron spin information (spintronics) in
solid-state quantum electronic devices is determined by the spin–lattice and
spin–spin relaxation times of electrons. Minimizing the effects of spin–orbit
coupling and the local magnetic contributions of neighbouring atoms on
spin–lattice and spin–spin relaxation times at room temperature remain
substantial challenges to practical spintronics. Here we report conduction
electron spin–lattice and spin–spin relaxation times of 175 ns at 300 K in
37±7 nm carbon spheres, which is remarkably long for any conducting solid-
state material of comparable size. Following the observation of spin
polarization by electron spin resonance, we control the quantum state of the
electron spin by applying short bursts of an oscillating magnetic field and
observe coherent oscillations of the spin state. These results demonstrate the
feasibility of operating electron spins in conducting carbon nanospheres as
quantum bits at room temperature
Colour changes upon cooling of Lepidoptera scales containing photonic nanoarchitectures
The effects produced by the condensation of water vapours from the ambient in
the various intricate nanoarchitectures occurring in the wing scales of several
Lepidoptera species were investigated by controlled cooling (from room
temperature to -5 - -10 {\deg}C) combined with in situ measurement of changes
in the reflectance spectra. It was determined that, due to this procedure, all
photonic nanoarchitectures giving a reflectance maximum in the visible range
and having an open nanostructure exhibited alteration of the position of the
reflectance maximum associated with the photonic nanoarchitectures. The
photonic nanoarchitectures with a closed structure exhibited little to no
alteration in colour. Similarly, control specimens coloured by pigments did not
exhibit a colour change under the same conditions. Hence, this effect can be
used to identify species with open photonic nanoarchitectures in their scales.
For certain species, an almost complete disappearance of the reflectance
maximum was found. All specimens recovered their original colours following
warming and drying. Cooling experiments using thin copper wires demonstrated
that colour alterations could be limited to a millimetre, or below. Dried
museum specimens do not exhibit colour changes when cooled in the absence of a
heat sink due to the low heat capacity of the wings.Comment: 18 pages, 9 figures, including supplemen
Near-infrared optical properties and proposed phase-change usefulness of transition metal disulfides
The development of photonic integrated circuits would benefit from a wider
selection of materials that can strongly-control near-infrared (NIR) light.
Transition metal dichalcogenides (TMDs) have been explored extensively for
visible spectrum opto-electronics, but the NIR properties of these layered
materials have been less-studied. The measurement of optical constants is the
foremost step to qualify TMDs for use in NIR photonics. Here we measure the
complex optical constants for select sulfide TMDs (bulk crystals of MoS2, TiS2
and ZrS2) via spectroscopic ellipsometry in the visible-to-NIR range. Through
Mueller matrix measurements and generalized ellipsometry, we explicitly measure
the direction of the ordinary optical axis. We support our measurements with
density functional theory (DFT) calculations, which agree with our measurements
and predict giant birefringence. We further propose that TMDs could find use as
photonic phase-change materials, by designing alloys that are thermodynamically
adjacent to phase boundaries between competing crystal structures, to realize
martensitic (i.e. displacive, order-order) switching.Comment: supplementary at end of document. 6 main figure
Electrochemical migration of Cu and Sn in Na2SO4 environment
The effect of Na2SO4 concentration on electrochemical migration (ECM) of copper and tin was investigated applying an in-situ optical and real-time electrical inspection system. According to the Mean-Time-To-Failure (MTTF) values, the ECM susceptibility of copper has increased at low concentration levels. However, the ECM susceptibility of copper has decreased at the medium and stopped at the high and even saturated concentration levels. On the other hand, the ECM susceptibility of tin has increased at low levels. Afterwards the ECM ability of tin was hindered and even stopped at medium level. Interestingly, the ECM susceptibility of tin was reappeared at high concentration levels
Rapid thickness reading of CH3NH3PbI3 nanowire thin films from color maps
Hybrid halide perovskite photovoltaic materials show a remarkable light conversion efficiency in various optoelectronic devices. In the fabrication of these solar cells, light emitting diodes, laser and photodetector prototypes the thickness of the perovskite is an important parameter since the light is absorbed within a thin layer of a few hundred nanometers. Nevertheless, making perovskite coatings with various solution-based and evaporation methods showing highly reproducible thickness and area coverage is still an issue. Therefore, rapid and reliable quality-control of the film morphology is needed. This report shows a simple, rapid, and calibration-free method for reading the thickness directly from the color map of nanowire perovskite films seen in standard optical microscope with visible light. (C) 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei
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