The equivalent widths (
W
) of 565 spectral lines in the wavelength range of 4690 – 6870 Å were evaluated at 31 consecutive points from the solar disk center (
μ
≡
cos
θ
=
1
) to near the limb (
μ
=
...0.25
) by applying the synthetic spectrum-fitting technique, in order to clarify the nature of their center–limb variations, especially the observed slope differing from line to line and its interpretation in terms of line properties. We found that the distribution of the gradient
β
(
≡
−
d
log
W
/
d
log
μ
)
well correlates with that of the
d
log
W
/
d
log
T
index, which means that the center-to-limb variation of
W
is determined mainly by the
T
-sensitivity of individual lines because the line-forming region shifts towards upper layers of lower
T
as we go toward the limb. Furthermore, the key to understanding the behavior of
d
log
W
/
d
log
T
(depending on the temperature sensitivity of number population) is whether the considered species is in minor population stage or major population stage, by which the distribution of
β
is explained in terms of differences in excitation potential and line strengths. All the center–limb data of equivalent widths (as well as line-of-sight turbulent velocity dispersions, elemental abundances, and mean line-formation depths derived as by-products) along with the solar spectra used for our analysis are made available as on-line materials.
Formation of oleogels based on edible lipid materials Dassanayake, Lakmali Samuditha K.; Kodali, Dharma R.; Ueno, S.
Current opinion in colloid & interface science,
10/2011, Letnik:
16, Številka:
5
Journal Article
Recenzirano
Oleogels may be defined as lipophilic liquid and solid mixtures, in which solid lipid materials (oleogelators) with lower concentrations (<10
wt.%) can entrap bulk liquid oil by ways of the formation ...of network of oleogelators in the bulk oil. The oelogelators can be grouped into two: self-assembly system and crystal particles system. This article reviewed recent work on the formation of oleogels using various types of oleogelators. The fundamental aspects of the formation of lipid network, kinetic and microscopic properties of oleogels are discussed with a special emphasis on crystal particle based oleogels. The potential applications of edible oil based-oleogels and their functionality are also described.
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► Comprehensive description of formation mechanisms of oleogels. ► New information of physical properties of oleogels based on edible lipids. ► Classification of edible oleogels in terms of molecular assembly systems and crystal particles systems.
Differential scanning calorimetry (DSC), optical microscopy, and X-ray diffraction (XRD) were used to examine the thermal behavior, crystal structure, and crystal morphology of rice bran wax (RBX) in ...bulk and oil-wax mixtures, and to compare them with those of carnauba wax (CRX) and candellila wax (CLX). The RBX employed in the present study was separated from rice bran oil by winterization, filtration, refinement, bleaching, and deodorization. The RBX crystals melted in the bulk state at 77-79 °C with ΔH melting = 190.5 J/g, which is quite large compared with CLX (129 J/g) and CRX (137.6 J/g). XRD data of the RBX crystals revealed O⊥ subcell packing and a long spacing value of 6.9 nm. Thin long needle-shaped crystals were observed in the mixtures of RBX and liquid oils olive oil and salad oil (canola:soy bean oil = 50:50); therefore, the dispersion of RBX crystals in these liquid oils was much finer than that of CRX and CLX crystals. Organogels formed when the mixture of every plant wax and liquid oil was melted at elevated temperature and cooled to ambient temperature. However, the mixture of RBX and olive oil at a concentration ratio of 1:99 wt.% formed an organogel at 20 °C, whereas the lowest concentration necessary for CRX to form an organogel in olive oil was 4 wt.% and that for CLX was 2 wt.%. Observation of the rate of gel formation using DSC and viscosity measurements indicated that the gel structure formed soon after RBX crystallized, whereas a time delay was observed between the organogel formation and wax crystallization of CRX and CLX. These results demonstrate RBX's good organogel-forming properties, mostly because of its fine dispersion of long needle like crystals in liquid oil phases.
We previously reported that PU.1 is downregulated in the majority of myeloma cell lines and primary myeloma cells of certain myeloma patients, and conditional expression of PU.1 in such myeloma cell ...lines induced cell cycle arrest and apoptosis. We found downregulation of IRF4 protein in the U266 myeloma cell line following induction of PU.1. Previous studies reported that knockdown of IRF4 in myeloma cell lines induces apoptosis, prompting us to further investigate the role of IRF4 downregulation in PU.1-induced cell cycle arrest and apoptosis in myeloma cells. PU.1 induced downregulation of IRF4 at the protein level, cell cycle arrest and apoptosis in six myeloma cell lines. Chromatin immunoprecipitation (ChIP) revealed that PU.1 directly binds to the IRF4 promoter, whereas a reporter assay showed that PU.1 may suppress IRF4 promoter activity. Stable expression of IRF4 in myeloma cells expressing PU.1 partially rescued the cells from apoptosis induced by PU.1. As it was reported that IRF4 directly binds to the IRF7 promoter and downregulates its expression in activated B cell-like subtype of diffuse large B cell lymphoma cells, we performed ChIP assays and found that IRF4 directly binds the IRF7 promoter in myeloma cells. It is known that IRF7 positively upregulates interferon-β (IFNβ) and induces apoptosis in many cell types. Binding of IRF4 to the IRF7 promoter decreased following PU.1 induction, accompanied by downregulation of IRF4 protein expression. Knockdown of IRF7 protected PU.1-expressing myeloma cells from apoptosis. Furthermore, IFNβ, which is a downstream target of IRF7, was upregulated in myeloma cells along with IRF7 after PU.1 induction. Finally, we evaluated the mRNA expression levels of PU.1, IRF4 and IRF7 in primary myeloma cells from patients and found that PU.1 and IRF7 were strongly downregulated in contrast to the high expression levels of IRF4. These data strongly suggest that PU.1-induced apoptosis in myeloma cells is associated with IRF4 downregulation and subsequent IRF7 upregulation.
This study examined the destabilization of an oil-in-water (O/W) emulsion by freeze-thawing with a focus on the influence of the morphology and polymorph of fat crystals. For a model of food ...emulsion, this study used a mayonnaise-type O/W emulsion containing 70wt% canola oil (canola emulsion) or soybean oil (soybean emulsion) stored at −15, −20, and −30°C. The freeze-thaw stabilities of the emulsions were evaluated by measuring the upper oil layer after freeze-thawing. The soybean emulsion kept at −20°C had the highest stability; the other emulsions were destabilized during 6h of storage. Crystallization in the emulsions was determined using differential scanning calorimetry (DSC), time variation of temperature, X-ray diffraction measurement, and polarized light microscopy. DSC thermograms indicated that crystallization in emulsions occurred first in the high-melting fraction of oil, followed by water and, last, in the low-melting fraction of oil during cooling to −40°C. In the canola emulsion, the amount of fat crystals derived from the low-melting fraction of oil increased during storage at all temperatures, resulting in partial coalescence. The soybean emulsion was expected to be destabilized by polymorphic transformation (sub-α to β′ and β) of fat crystals derived from the high-melting fraction during storage at −15 and −20°C. However, the soybean emulsion did not exhibit polymorphic transformation stored at −30°C, and the amount of fat crystals did not increase during freezing; thus, it was destabilized via a different mechanism.
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•Destabilization mechanisms of O/W emulsion by freeze-thawing were proposed.•Partial coalescence was clearly observed in canola oil in water emulsion.•Soybean oil in water emulsion was destabilized by polymorphic transformation of fat crystals.
A very slight rotation-induced latitudinal temperature variation (presumably on the order of several kelvin) on the solar surface is theoretically expected. While recent high-precision solar ...brightness observations reported its detection, confirmation by an alternative approach using the strengths of spectral lines is desirable, for which reducing the noise due to random fluctuation caused by atmospheric inhomogeneity is critical. Toward this difficult task, we carried out a pilot study of spectroscopically investigating the relative variation of temperature (
T
) at a number of points in the solar circumference region near to the limb (where latitude dependence should be detectable, if any exists) based on the equivalent widths (
W
) of 28 selected lines in the 5367 – 5393 Å and 6075 – 6100 Å regions. We paid special attention to i) clarifying which types of lines should be employed and ii) how much precision is attainable in practice. We found that lines with strong
T
-sensitivity (
|
log
W
/
log
T
|
) should be used and that very weak lines should be avoided because they inevitably suffer strong relative fluctuations (
Δ
W
/
W
). Our analysis revealed that a precision of
Δ
T
/
T
≈
0.003
(corresponding to ≈ 15 K) can be achieved at best by a spectral line with comparatively large
|
log
W
/
log
T
|
, although this can possibly be further improved When a number of lines are used all together. Accordingly, if many such favorable lines could be measured with subpercent precision of
Δ
W
/
W
and by averaging the resulting
Δ
T
/
T
from each line, the random noise would eventually be reduced to ≲ 1 K and detection of a very subtle amount of global
T
-gradient might be possible.
In this paper, we present the analysis and results of a direct measurement of the cosmic-ray proton spectrum with the CALET instrument onboard the International Space Station, including the detailed ...assessment of systematic uncertainties. The observation period used in this analysis is from October 13, 2015 to August 31, 2018 (1054 days). We have achieved the very wide energy range necessary to carry out measurements of the spectrum from 50 GeV to 10 TeV covering, for the first time in space, with a single instrument the whole energy interval previously investigated in most cases in separate subranges by magnetic spectrometers (BESS-TeV, PAMELA, and AMS-02) and calorimetric instruments (ATIC, CREAM, and NUCLEON). The observed spectrum is consistent with AMS-02 but extends to nearly an order of magnitude higher energy, showing a very smooth transition of the power-law spectral index from -2.81±0.03 (50-500 GeV) neglecting solar modulation effects (or -2.87±0.06 including solar modulation effects in the lower energy region) to -2.56±0.04 (1-10 TeV), thereby confirming the existence of spectral hardening and providing evidence of a deviation from a single power law by more than 3σ.
Extended results on the cosmic-ray electron + positron spectrum from 11 GeV to 4.8 TeV are presented based on observations with the Calorimetric Electron Telescope (CALET) on the International Space ...Station utilizing the data up to November 2017. The analysis uses the full detector acceptance at high energies, approximately doubling the statistics compared to the previous result. CALET is an all-calorimetric instrument with a total thickness of 30 X_{0} at normal incidence and fine imaging capability, designed to achieve large proton rejection and excellent energy resolution well into the TeV energy region. The observed energy spectrum in the region below 1 TeV shows good agreement with Alpha Magnetic Spectrometer (AMS-02) data. In the energy region below ∼300 GeV, CALET's spectral index is found to be consistent with the AMS-02, Fermi Large Area Telescope (Fermi-LAT), and Dark Matter Particle Explorer (DAMPE), while from 300 to 600 GeV the spectrum is significantly softer than the spectra from the latter two experiments. The absolute flux of CALET is consistent with other experiments at around a few tens of GeV. However, it is lower than those of DAMPE and Fermi-LAT with the difference increasing up to several hundred GeV. The observed energy spectrum above ∼1 TeV suggests a flux suppression consistent within the errors with the results of DAMPE, while CALET does not observe any significant evidence for a narrow spectral feature in the energy region around 1.4 TeV. Our measured all-electron flux, including statistical errors and a detailed breakdown of the systematic errors, is tabulated in the Supplemental Material in order to allow more refined spectral analyses based on our data.
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