Introduction
Centranthus kellereri
is a Bulgarian endemic plant species, found only in two locations in the world: The Balkans Mountains (Stara Planina), above the town of Vratsa, and The Pirin ...Mountains, above the town of Bansko, Bulgaria. Being endemic and endangered species precluded any significant research on it. The hypothesis of this study was that the populations of
C
.
kellereri
may represent genetically, phytochemically, and morphologically distinct forms and these will differentiate from
C
.
ruber
. Furthermore,
C
.
kellereri
possibly imperfect embryology may preclude its more widespread distribution under natural conditions.
Results
This study revealed the phytochemical profile, antioxidant activity, embryology, surface microstructural morphological traits, and genetic differences between the
C
.
kellereri
plants from the only two natural populations and compares them to the ones of the related and better-known plant
C
.
ruber
. The essential oil (EO) content in aboveground plant parts and in roots was generally low and the EO composition varied significantly as a function of plant part, year of sampling, location, and species. Methylvaleric acid was a major EO constituent in the
C
.
kellereri
EO, ranging between 60.2% and 71.7% of the total EO. The EO included monoterpenes, sequiterpenes, long-chain alkanes and fatty acids. Phytochemical analyses of plant tissue revealed the occurrence of 32 compounds that were tentatively identified as 6 simple phenolics, 18 flavonoids, 1 quinone, 1 lipid, 1 alkaloid, 2 diterpenes, and 3 triterpenes. There were differences in detected compounds between the
C
.
kellereri
plants at the two locations and between the roots and shoots in both species. The total phenols and flavonoids varied between the two species but were also dissimilar between the plants from the two populations of
C
.
kelleri
. Free radical scavenging activity, measured with ABTS and DPPH in aqueous and methanol extracts, had similar values; however, overall,
C
.
kellereri
from Vratsa showed the highest antioxidant activity while
C
.
ruber
had the lowest activity. Genetic analyses showed a clear differentiation between
C
.
kellereri
and
C
.
ruber
, and between the two populations of
C
.
kellereri
. Embryological studies revealed the peculiarities of the male and female generative spheres of the two species that were defined as being sexually reproducing. The pollen had high viability; however, the low viability of seeds demonstrated possible high sensitivity of
C
.
kellereri
to the environmental conditions, perhaps the main factor modifying and restricting the population sizes. The SEM analyses exposed differences in surface microstructural traits between the species (C.
kellereri
and
C
.
ruber
) but also between the two populations of
C
.
kellereri
. The observed dissimilarities in genetic makeup, micromorphological characteristics, and phytochemical composition strongly indicate that the two populations can be classified as distinct subspecies or varieties of
C
.
kellereri
; var.
pirinensis
and var.
balkanensis
. Further research is needed to introduce
C
.
kellereri
into culture and develop it as a high-value specialty crop or ornamental in order to conserve
C
.
kellereri
natural populations.
C
.
kellereri
may be utilized as a source for phytochemicals of interest and as an ornamental plant like
C
.
ruber
; however, it may have a greater environmental plasticity and adaptation as evidenced by its current locations.
Sodium-deficient nickel–manganese oxides with a layered type of structure are, nowadays, of great interest as electrode materials for both lithium- and sodium-ion batteries since they are able to ...intercalate lithium and sodium ions reversibly within a broad concentration range. Herein, we report new data on the effects of the particle sizes and of the electrolyte salt on the intercalation properties of Na2/3Ni0.5Mn0.5O2 with a P3-type of structure. The morphology of layered Na2/3Ni0.5Mn0.5O2 oxides has been varied by changing the type of the precursor used: from Na–Ni–Mn acetates to Na–Ni–Mn mixed nitrate acetates. The structure, particle dimensions, and particle size distribution of oxides have been determined by means of powder X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light-scattering measurements, and X-ray photoelectron spectroscopy (XPS). The intercalation properties of Na2/3Ni0.5Mn0.5O2 have been studied in model electrochemical cells versus Li metal as the anode. We used two kinds of lithium salts dissolved in organic solutions as the electrolytes: 1 M LiPF6 in EC:DMC and 1 M LiBF4 in EC:DMC. The mechanism of the lithium intercalation into Na2/3Ni0.5Mn0.5O2 is discussed on the basis of e x situ XRD, HRTEM, and X-ray photoelectron spectroscopy analyses. It has been discovered that the lithium salt in the electrolyte salt contributes to the mechanism of the electrochemical reaction, while particle dimensions determine the capacity stability during continuous cycling, as well as the surface reactivity of oxide electrodes.
We present a measurement of the W boson pair-production cross section in p(p) over bar collisions at a center-of-mass energy of root s=1.96 TeV. The data, collected with the Run II D0 detector at ...Fermilab, correspond to an integrated luminosity of 224-252 pb(-1) depending on the final state (ee, e mu, or mu mu). We observe 25 candidates with a background expectation of 8.1 +/- 0.6(stat)+/- 0.6(syst)+/- 0.5(lum) events. The probability for an upward fluctuation of the background to produce the observed signal is 2.3x10(-7), equivalent to 5.2 standard deviations. The measurement yields a cross section of 13.8(-3.8)(+4.3)(stat)(-0.9)(+1.2)(syst)+/- 0.9(lum) pb, in agreement with predictions from the standard model.
We present a study of top quark polarization in $t \overline{t}$ events produced in $p \overline{p}$ collisions at $\sqrt{s}=1.96$ TeV. Data correspond to 9.7 fb$^{-1}$ collected with the D0 detector ...at the Tevatron. We use final states containing a lepton and at least three jets. The polarization is measured using the distribution of leptons along the beam and helicity axes, and the axis normal to the production plane. This is the first measurement of top quark polarization at the Tevatron in $\ell$+jets final states, and first measurement of transverse polarization in $t \overline{t}$ production. The observed distributions are consistent with the standard model.
We studied electrochemical alkaline systems whose Zn electrodes (anodes) contain active mass produced from composites of ZnO and B(Pb)SCCO 2212 conductive cuprate ceramics. The ceramics was added at ...concentrations of 5, 7 or 10 wt.%. The resulting material was structurally characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Electrochemical cells assembled with anode prepared using active mass made by employing such composites, were examined by electrochemical impedance spectroscopy. The effect from the concentration of B(Pb)SCCO 2212 ceramics on the impedimetric response and tangent loss spectra of the electrochemical cells was studied. The results show that compared to 7 wt.% and 10 wt.% concentration of B(Pb)SCCO 2212 conductive ceramics added to the Zn material of the anode, the concentration of 5 wt.% leads to lower electric losses in the assembled electrochemical cells.
This report aims to analyze the impact of state grants upon the effectiveness efficiency of the enterprises in the Agricultural sector. The presence/absence of the correlation between the “received ...state grants - financial results from the activity of the agricultural enterprises” was studied. The efficiency of agricultural enterprises is expressed through the indicators of profitability and productivity. The empirical data for a period of 10 years 2008 – 2017 were shown in the study. The main activities of the surveyed enterprises are crop, livestock and combined - crop-livestock. Based on the results obtained, it is expected that the receipt of grants will have a positive influence on the performance of enterprises in the agricultural sector, measured by indicators of effectiveness and productivity. The following research hypotheses have been proved: the positive effect of the grant is more obvious in larger agricultural enterprises, which have higher productivity and profitability compared to small and medium-sized farms; agricultural enterprises which receive grants and are characterized by higher investment activity and are also characterized by higher innovation activity; based on the predominant number of crop enterprises, it is assumed that this type of activity leads to the achievement of higher financial results as a result of the activity of the agricultural enterprises; the age of the enterprises, expressed through the years of their activity, contributes significantly to higher profitability and productivity of the carried out activity.
The genus
(Solanaceae) includes over 70 species, with a long history of traditional use; many of them are nowadays used in bioengineering, biosynthesis, molecular biology, and other studies, while ...common tobacco,
L., is one of the most economically important industrial crops worldwide. Although
species have been extensively investigated, relatively less research has focused on flowers, especially research related to obtaining aromatic products for cosmetic and perfumery use. On the other hand, there is evidence that
flowers accumulate various secondary metabolites with a distinct aroma and biological activities, and the flowers represent a biomass available in sufficient quantities. Therefore, this study aimed to determinate the chemical composition (by GC-MS) and the olfactory profiles of a specific type of natural aromatic product (concrete), obtained from the flowers of four
species, in a direct comparison between them. The yields of extracted concrete were sufficiently high, varying between the species, 1.4% (
L.), 2.5% (
L.), 1.6% (
Link&Otto genotype with white flowers), 2.7% (
genotype with pink flowers), 3.2% (
, Oriental type), and 5.2% (
, Virginia type). The major components of the obtained concretes belonged to different chemical classes:
and
(OR), the hydrocarbons
-tetratriacontane (14.5%; 15.0%) and
-triacontane (12.1%; 13.3%), and 3-methyl-pentanoic acid (11.1%; 12.2%);
, the diterpenes sclareol (25.9%), 3-α-hydroxy-manool (16.3%), and 13-epimanool (14.9%);
(WF), the phenylpropanoid terephthalic acid and di(2-ethylhexyl) ester (42.9%);
(PF), the diterpene tributyl acetylcitrate (30.7%); and
(FCV), the hydrocarbons
-hexacosane (12.9%) and
-pentacosane (12.9%). Each of the flower concretes revealed a characteristic odor profile. This is the first report about
species as a source for obtaining flower concretes; these initial results about the concrete yield, olfactory profile, and chemical composition are a prerequisite for the possible processing of
flowers into new aromatic products for use in perfumery and cosmetics. The study provides new data in favor of the potential of the four
species as aromatic plants, as well as a possible alternative use of flowers, a valuable, but discarded, plant material in other applications.
In this contribution we provide novel data on the reversible lithium and sodium ion intercalation into a sodium-manganese phospho-olivine NaMnPO
4
, when it is used as a cathode in model lithium-ion ...cells. The ion-exchange reaction involving the participation of KMnPO
4
·H
2
O dittmarite as precursor was chosen for the preparation of NaMnPO
4
. The NaMnPO
4
particles were covered with carbonaceous materials to improve the electrical conductivity and electrolyte wetting. The procedure includes ball-milling of NaMnPO
4
with conductive carbon black additives Super C/65, followed by thermal treatment. The mechanically treated samples consist of well crystallized phospho-olivine phase NaMnPO
4
free of any anti-site defects and disordered carbon species with graphite like medium-range order. The composite NaMnPO
4
/C material manifests a reversible capacity between 80-85 mA h g
−1
in model lithium cells
versus
lithium anode. Prior to the electrochemical test, the chemical inertness of NaMnPO
4
in the lithium electrolyte is studied by soaking phospho-olivines in the solution of LiPF
6
in EC:DMC. The mechanism of the reversible intercalation/deintercalation cycling is investigated using
ex situ
X-ray powder diffraction, TEM and high-angle annular dark field STEM analysis, infrared spectroscopy and electron paramagnetic resonance spectroscopy (EPR). The study demonstrates, for the first time, that NaMnPO
4
is able to intercalate reversibly both Na
+
and Li
+
ions following the chemical reaction Li
x
Na
1−
x
MnPO
4
↔ Li
0.0
Na
0.5
MnPO
4
(0.25 ≤
x
≤ 0.45).
The study demonstrates unusual capabilities of phospho-olivine NaMnPO
4
to intercalate lithium and sodium reversibly, which makes it attractive electrode material instead of the conventional lithium analogue LiMnPO
4
.
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