A complex coacervate was prepared with whey protein isolate (WPI) and tamarind seed mucilage (TSM) and was compared with a commonly used whey protein isolate (WPI)-gum Arabic (GA) complex coacervate. ...Protolityc titration, ζ-potentiometry and turbidimetry analyses were used to determine structural transitions during coacervate formation. Hydrocolloid blending ratio and pH effects on phase transitions were examined to finding the maximum strength interaction of the complex coacervates. The optimum WPI-TSM complex coacervate ratio and the pH value were 1:0.3 and 3.68, respectively. In contrast, the WPI-GA complex coacervate reached the optimal interaction at ratio of 1.4:1 and pH = 3.46. The complex coacervates were spray-dried and analyzed to characterize structural, morphological and thermal properties. The results of FTIR showed that the formation of complexes was by means of electrostatic interactions and hydrogen bonds. The XRD analysis of WPI-TSM complex revealed higher crystallinity with respect to WPI-GA complex. The spray-dried complex coacervates exhibited clusters of amorphous aggregates, smooth and non-fractured particles. Thermal stability showed that coacervation enhanced protein stability as compared to WPI alone. Besides, WPI-TSM complex coacervate exhibited higher thermal stability than its WPI-GA counterpart. Therefore, WPI-TSM complex coacervate can be used as an economic and nutritionally valuable alternative for food additives.
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•A novel WPI-TSM complex was carried out mainly by electrostatic interactions.•The WPI-TSM complex presented greater stability than WPI-GA complex.•The spray-dried complex coacervates possessed a morphology smooth with concavities.•The crystallinity degree of the complex coacervates was determined by XRD.•Thermal stability against denaturation of WPI-TSM complex coacervate was improved.
•Flexible Supercapacitors (SCs) were fabricated with graphene electrodes (FGEs).•The Capacitance of the SCs was enhanced by decorating the FGEs with CoFe2O4 nanoparticles.•The presence of CoFe2O4 ...nanoparticles on the FGEs prolonged the discharge times of the SCs.
This work reports the use of cobalt ferrite nanoparticles (NPs) for the fabrication of flexible supercapacitors (SCs). According to the microscopy analysis, the cobalt ferrite NPs have quasi-spherical shapes and their average sizes were 10.2 ± 1 nm, 12.3 ± 1 nm and 8.8 ± 1 nm when they are synthesized with cobalt concentrations of 0, 25 and 33 mol%, respectively. Moreover, the X-ray diffraction patterns indicated that all the cobalt ferrite NPs presented a cubic phase. Flexible supercapacitors were made with two flexible graphene electrodes (FGEs) and one of them (anode) was coated with different cobalt ferrite NPs (the FGE electrode had 5 wt percent (wt%) of NPs) synthesized with several cobalt concentrations. The electrochemical characterization of these flexible SCs revealed that not only the capacitance was enhanced from 77.8–337.1 F g−1 (at 1 A g−1) when the cobalt concentration increases from 0 to 33 mol% but also the discharge times from 1650 to 4957 s. Moreover, other SCs devices were fabricated using different wt% of the cobalt ferrite synthesized with a cobalt concentration of 33 mol%. As a result, the capacitance increases from 337.1–835.7 F g-1 (at 1 A g−1) and the discharge times from 4957 to 21969s when the content of cobalt ferrite increases from 5 to 10 wt%. The enhancement of capacitance and discharge times was associated to the increase of the surface area and electrical conductivity of the anodes, which was caused by the presence of cobalt ferrite NPs on them.
In this investigation, time-dependent carbon nanostructures were prepared by high-energy ball milling in the air from elemental graphite powders. Scanning electron microscopy (SEM), X-ray diffraction ...(XRD), Raman spectroscopy (RS), and high-resolution transmission electron microscopy (HRTEM) characterized the ball-milled powders. XRD analysis showed that the crystal size decreased with the milling time. Raman spectra confirmed the presence of carbon nanostructures with sp
2
hybridization. Meanwhile, HRTEM images revealed different carbon morphologies during the milling time. During the different stages, it appears distortion of layers, large tapes, polyhedral morphologies, nanocapsules, and nano-onions. These carbon nanostructures occur in regions where there is carbon accumulation. In this way, the ball milling process in air conditions can promote distorted carbon and different morphologies.
The aim of this work was to assess the uptake of citrate-coated magnetite nanoparticles (NPs) by wheat plants and its effect on the bioaccumulation and toxicity of individual and joint Cd2+ and Cr6+ ...levels. Seven-day assays were conducted using quartz sand as the plant growth substrate. The endpoints measured were seed germination, root and shoot lengths, and heavy metal accumulation. Magnetite exhibited very low toxicity, regardless of the wheat seedling NP uptake and distribution into roots and shoots. The seed germination and shoot length were not sensitive enough, while the root length was a more sensitive toxicity endpoint. The root length of wheat seedlings exposed to individual metals decreased by 50% at 2.67mgCd2+kg−1 and 5.53mgCr6+kg−1. However, when magnetite NPs (1000mgkg−1) were added, the root length of the plants increased by 25 and 50%. Cd2+ and Cr6+ showed similar and noninteractive joint action, but strongly impaired the wheat seedlings. In contrast, an interactive infra-additive or antagonistic effect was observed upon adding magnetite NPs. Thus, cadmium and chromium accumulation in vegetable tissues was considerately diminished and the toxicity alleviated.
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•We assessed the effect of nanomagnetite on heavy metal toxicity in wheat plants.•Citrate-coated magnetite nanoparticles (NPs) exerted very low toxicity to plants.•Cadmium was more toxic than chromium and toxicity was mitigated by magnetite NPs.•Cadmium and chromium had a similar and noninteractive joint action on plants.•Metals showed an interactive infra-additive joint effect by adding magnetite NPs.
ABSTRACT The investigation of the nonlinearity of the Leavitt law (LL) is a topic that began more than seven decades ago, when some of the studies in this field found that the LL has a break at about ...10 days. The goal of this work is to investigate a possible statistical cause of this nonlinearity. By applying linear regressions to OGLE-II and OGLE-IV data, we find that to obtain the LL by using linear regression, robust techniques to deal with influential points and/or outliers are needed instead of the ordinary least-squares regression traditionally used. In particular, by using M- and MM-regressions we establish firmly and without doubt the linearity of the LL in the Large Magellanic Cloud, without rejecting or excluding Cepheid data from the analysis. This implies that light curves of Cepheids suggesting blending, bumps, eclipses, or period changes do not affect the LL for this galaxy. For the Small Magellanic Cloud, when including Cepheids of this kind, it is not possible to find an adequate model, probably because of the geometry of the galaxy. In that case, a possible influence of these stars could exist.
The Imaging Magnetograph eXperiment (IMaX) is a spectropolarimeter built by four institutions in Spain that flew on board the
Sunrise
balloon-borne solar observatory in June 2009 for almost six days ...over the Arctic Circle. As a polarimeter, IMaX uses fast polarization modulation (based on the use of two liquid crystal retarders), real-time image accumulation, and dual-beam polarimetry to reach polarization sensitivities of 0.1%. As a spectrograph, the instrument uses a LiNbO
3
etalon in double pass and a narrow band pre-filter to achieve a spectral resolution of 85 mÅ. IMaX uses the high-Zeeman-sensitive line of Fe
i
at 5250.2 Å and observes all four Stokes parameters at various points inside the spectral line. This allows vector magnetograms, Dopplergrams, and intensity frames to be produced that, after reconstruction, reach spatial resolutions in the 0.15 – 0.18 arcsec range over a 50×50 arcsec field of view. Time cadences vary between 10 and 33 s, although the shortest one only includes longitudinal polarimetry. The spectral line is sampled in various ways depending on the applied observing mode, from just two points inside the line to 11 of them. All observing modes include one extra wavelength point in the nearby continuum. Gauss equivalent sensitivities are 4 G for longitudinal fields and 80 G for transverse fields per wavelength sample. The line-of-sight velocities are estimated with statistical errors of the order of 5 – 40 m s
−1
. The design, calibration, and integration phases of the instrument, together with the implemented data reduction scheme, are described in some detail.
The adsorption of As(III) on cobalt and manganese ferrite nanoparticles (NPs) was studied. The ferrite NPs were synthesized using the Massart-assisted microwave hydrothermal treatment. All the NPs ...exhibited the spinel structure with a formula such as M
x
Fe
3−
x
O
4
, where M = Co or Mn, and
x
runs from 0.21 to 1.14. The changes in the stoichiometry caused different effects on the physical properties as well on the As(III) adsorption capacity of the NPs. The adsorption data were fitted in very good agreement with the Freundlich model. It was concluded that As(III) was better attracted to ferrimagnetic cobalt ferrite NPs, given that the arsenic removal was significantly higher than that exhibited by superparamagnetic manganese-substituted ferrite NPs.
Cobalt ferrite nanoparticles (NPs) have received increasing attention due to their widespread therapeutic and agricultural applicability. In the environmental field, dry powder- and ...ferrofluid-suspended cobalt ferrite NPs were found to be useful for removing heavy metals and metalloids from water, while diluted suspensions of cobalt ferrite NP have been promisingly applied in medicine. However, the potential toxicological implications of widespread exposure are still unknown. Since cobalt ferrite NPs are considered residual wastes of environmental or medical applications, plants may serve as a point-of-entry for engineered nanomaterials as a result of consumption of these plants. Thus, the aim of this study was to assess the effects of dry powder and fresh cobalt ferrite NP on wheat plants. Seven-day assays were conducted, using quartz sand as the plant growth substrate. The toxicity end points measured were seed germination, root and shoot lengths, total cobalt (Co) and iron (Fe) accumulation, photosynthetic pigment production, protein (PRT) production, and activities of catalase (CAT), ascorbate peroxidase (APX), and guaiacol peroxidase (GPX). Increasing total Co and Fe in plant tissues indicated that wheat plants were exposed to cobalt ferrite NP. Seed germination and shoot length were not sufficiently sensitive toxicity end points. The effective concentration (EC
50
) that diminished root length of plants by 50% was 1963 mg/kg for fresh ferrite NPs and 5023 mg/kg for powder ferrite NP. Hence, fresh ferrite NPs were more toxic than powder NP. Plant stress was indicated by a significant decrease in photosynthetic pigments. CAT, APX, and GPX antioxidant enzymatic activity suggested the generation of reactive oxygen species and oxidative damage induced by cobalt ferrite NP. More studies are thus necessary to determine whether the benefits of using these NPs outweigh the risks.
Context. Though there is increasing evidence linking the moat flow and the Evershed flow along the penumbral filaments, there is not a clear consensus regarding the existence of a moat flow around ...umbral cores and pores, and the debate is still open. Solar pores appear to be a suitable scenario to test the moat-penumbra relation as they correspond to a direct interaction between the umbra and the convective plasma in the surrounding photosphere without any intermediate structure in between. Aims. We study solar pores based on high-resolution ground-based and satellite observations. Methods. Local correlation tracking techniques were applied to different-duration time series to analyze the horizontal flows around several solar pores. Results. Our results establish that the flows calculated from different solar pore observations are coherent among each other and show the determining and overall influence of exploding events in the granulation around the pores. We do not find any sign of moat-like flows surrounding solar pores, but a clearly defined region of inflows surrounding them. Conclusions. The connection between moat flows and flows associated to penumbral filaments is hereby reinforced.
High-resolution time series of sunspots have been obtained with the Swedish 1 m Solar Telescope between 2003 and 2006 at different locations on the solar disk. Proper motions in seven different ...active regions have been studied. The analysis was performed by applying local correlation tracking to every series of sunspots, each of them more than 40 minutes long. The sunspots' shapes include a different variety of penumbral configurations. We report on the systematic behavior of the large-scale outflows surrounding the sunspots, commonly known as moat flows, that are essentially present only when preceded by a penumbra not tangential but perpendicular to the sunspot border. We present one case for which this rule appears not to be confirmed. We speculate that the magnetic neutral line, which is located in the vicinity of the anomalous region, might be responsible for blocking the outflow. These new results confirm the systematic and strong relation between the moat flows and the existence of penumbrae. A comparative statistical study between moats and standard granulation is also performed.
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