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Open AccessArticle
Seasonal Variations in the Chemical Composition of Liangshan Olive Leaves and Their Antioxidant and Anticancer Activities
Foods 2019, 8(12), 657; https://doi.org/10.3390/foods8120657 (registering DOI) - 08 Dec 2019
Abstract
The seasonal changes in the chemical composition of Olea europaea leaves from January to December at Liangshan (China) have been investigated. The highest total phenolic content (TPC), total flavonoid content (TFC), and free amino acid content (FAAC) levels were found in May and [...] Read more.
The seasonal changes in the chemical composition of Olea europaea leaves from January to December at Liangshan (China) have been investigated. The highest total phenolic content (TPC), total flavonoid content (TFC), and free amino acid content (FAAC) levels were found in May and December, while the lowest levels were detected in April and September. The soluble protein content (SPC) and the soluble sugar content (SSC) were highest in spring but lowest in summer and winter. The levels of major phenolic compounds, including oleuropein, and luteolin-4’-O-glucoside, followed by apigenin-7-O-glucoside, quercetin, rutin, luteolin, and apigenin, increased during spring and winter but decreased during summer and autumn. In addition, phenolic extracts (PEs) showed dose-dependent antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and superoxide radical scavenging activity assays; the reducing power was tested. The anticancer activities of PE at various concentrations were assessed by a cell counting kit-8 (CCK-8), and the IC50 (50% effective concentration) to HEK293, HeLa, and S180 cells were 841.48, 7139, and 457.69 μg/mL, respectively. PE-treated S180 cells inhibited proliferation through activation of caspase-3/9 and disruption of the mitochondrial membrane potential. Thus, PE in Liangshan olive leaves possessed strong antioxidant and anticancer potential, and spring and winter were determined as optimal harvesting seasons. Full article
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Open AccessArticle
Titanium and Vanadium Catalysts with 2-Hydroxyphenyloxazoline and Oxazine Ligands for Ethylene-Norbornene (co)Polymerization
Catalysts 2019, 9(12), 1041; https://doi.org/10.3390/catal9121041 (registering DOI) - 08 Dec 2019
Abstract
A series of titanium and vanadium complexes with oxazoline 2-(4,5-dihydro-1,3-oxazol-2-yl)phenol (L1), 2-(4-methyl-4,5-dihydro-1,3-oxazol-2-yl)phenol (L2), and oxazine 2-(5,6-dihydro-4H-1,3-oxazin-2-yl)phenol (L3) ligands were synthesized, and their structures were determined by NMR and MS methods as (L)2MtCl2. The vanadium complexes were found [...] Read more.
A series of titanium and vanadium complexes with oxazoline 2-(4,5-dihydro-1,3-oxazol-2-yl)phenol (L1), 2-(4-methyl-4,5-dihydro-1,3-oxazol-2-yl)phenol (L2), and oxazine 2-(5,6-dihydro-4H-1,3-oxazin-2-yl)phenol (L3) ligands were synthesized, and their structures were determined by NMR and MS methods as (L)2MtCl2. The vanadium complexes were found to be highly active in ethylene (7300 kgPE/(molV·h)) and ethylene/norbornene (5300 kgPE/(molV·h)) (co)polymerization. The polyethylene characteristics were melting temperature (123–142 °C), crystallinity degree (49–75%), molecular weight (8.5–7.2 × 105 g/mol), molecular weight distribution (1.5–2.4). The ethylene-norbornene (E-NB) copolymer characteristics were molecular weight (2.6–0.9 × 105 g/mol), molecular weight distribution (1.6–2.2), glass transition temperature (4–62 °C), norbornene incorporation (12.3–30.1 mol%) at initial concentration (0.5–1.5 mol/L). The microstructure of E-NB copolymers depends on the catalyst applied with the highest diads content for the (L3)2VCl2 and triads for the (L2)2VCl2 complexes. Full article
(This article belongs to the Section Catalysis in Organic and Polymer Chemistry)
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Open AccessReview
Influence of Saccharomyces and non-Saccharomyces Yeasts in the Formation of Pyranoanthocyanins and Polymeric Pigments during Red Wine Making
Molecules 2019, 24(24), 4490; https://doi.org/10.3390/molecules24244490 (registering DOI) - 08 Dec 2019
Abstract
Yeast are able to modulate many sensory parameters of wines during red must fermentation. The effect on color and on the formation of derived pigments during fermentation has been studied thoroughly since the 90s. Yeast can increase grape anthocyanin’s color by acidification by [...] Read more.
Yeast are able to modulate many sensory parameters of wines during red must fermentation. The effect on color and on the formation of derived pigments during fermentation has been studied thoroughly since the 90s. Yeast can increase grape anthocyanin’s color by acidification by hyperchromic effect (increase of flavylium molecules). Recent studies with non-Saccharomyces species, as Lachancea thermotolerans, described the intense effect of some strains on anthocyanin’s color, and subsequent, stability, by strongly reducing wine’s pH during fermentation. Moreover, selected yeast strains of Saccharomyces have been shown to release metabolites such as pyruvic acid or acetaldehyde that promote the formation of vitisin A and B pyranoanthocyanins during must fermentation. Schizosaccharomyces pombe, because of its specific metabolism, can produce higher concentrations of pyruvate, which enhances the formation of vitisin A-type derivatives. The hydroxycinnamate decarboxylase activity that some Saccharomyces strains express during fermentation also promotes the formation of vinylphenolic derivatives. Some non-Saccharomyces species, such as S. pombe or P. guilliermondii can also improve the production of these derivatives compared to selected strains of Saccharomyces cerevisiae. Lastly, some yeasts are also able to modulate the formations of polymeric pigments between grape anthocyanins and flavonoids, such as catechins and procyanidins. Full article
(This article belongs to the Special Issue Flavonoids: From Structure to Health Issues II)
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Open AccessFeature PaperArticle
Efficient Evaluation of Slowly Converging Integrals Arising from MAP Application to a Spectral-Domain Integral Equation
Electronics 2019, 8(12), 1500; https://doi.org/10.3390/electronics8121500 (registering DOI) - 08 Dec 2019
Abstract
Our problem was formulated in the vector Hankel transform domain and discretized via the Galerkin method, with expansion functions reconstructing the physical behavior of the surface current density. This ensured fast convergence in terms of the truncation order, but involved numerical evaluation of [...] Read more.
Our problem was formulated in the vector Hankel transform domain and discretized via the Galerkin method, with expansion functions reconstructing the physical behavior of the surface current density. This ensured fast convergence in terms of the truncation order, but involved numerical evaluation of slowly converging integrals to fill in the coefficient matrix. To overcome this problem, appropriate contributions were pulled out of the kernels of the integrals, which led to integrands transforming into exponentially decaying functions. Subsequently, integrals of the extracted contributions were expressed as linear combinations of fast-converging integrals via the Cauchy integral theorem. As shown in the numerical results section, the proposed technique drastically outperformed the classical analytical asymptotic-acceleration technique. Full article
(This article belongs to the Special Issue Computational Electromagnetics and Its Applications)
Open AccessArticle
Cooperative Learning and Students’ Motivation, Social Interactions and Attitudes: Perspectives from Two Different Educational Stages
Sustainability 2019, 11(24), 7005; https://doi.org/10.3390/su11247005 (registering DOI) - 08 Dec 2019
Abstract
The goal of the study was to contrast the effects that a Cooperative Learning implementation in Physical Education can produce in two different Educational stages: Primary and Secondary Education. A total of 179 students agreed to participate: 96 (44 boys, 52 girls) were [...] Read more.
The goal of the study was to contrast the effects that a Cooperative Learning implementation in Physical Education can produce in two different Educational stages: Primary and Secondary Education. A total of 179 students agreed to participate: 96 (44 boys, 52 girls) were enrolled in four Year 7 Primary Education groups (11.37 ± 0.89 years) and 83 students (38 boys, 45 girls) were enrolled in three Year 11 Secondary Education groups (15.42 ± 1.12 years). Convenience sampling was used. All groups experienced three consecutive learning units (23 sessions). At post-test, motivation increased significantly in the two groups (p = 0.031, p = 0.029), while social interaction only in the Secondary Education group (p = 0.024), and a significant difference between groups was also obtained in the post-test (p = 0.034). All effect sizes exceed the value of 0.87, which is considered large. Qualitative data showed that the teacher highlighted the importance of cooperation in Physical Education in order to promote respect for others and joint thinking in Primary Education. Full article
(This article belongs to the Special Issue Physical Education, Health Promotion, and Sustainability)
Open AccessArticle
312 MAX Phases: Elastic Properties and Lithiation
Materials 2019, 12(24), 4098; https://doi.org/10.3390/ma12244098 (registering DOI) - 08 Dec 2019
Abstract
Interest in the Mn+1AXn phases (M = early transition metal; A = group 13–16 elements, and X = C or N) is driven by their ceramic and metallic properties, which make them attractive candidates for numerous applications. In the present [...] Read more.
Interest in the Mn+1AXn phases (M = early transition metal; A = group 13–16 elements, and X = C or N) is driven by their ceramic and metallic properties, which make them attractive candidates for numerous applications. In the present study, we use the density functional theory to calculate the elastic properties and the incorporation of lithium atoms in the 312 MAX phases. It is shown that the energy to incorporate one Li atom in Mo3SiC2, Hf3AlC2, Zr3AlC2, and Zr3SiC2 is particularly low, and thus, theoretically, these materials should be considered for battery applications. Full article
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Open AccessArticle
Leaf Physiological Responses to Drought Stress and Community Assembly in an Asian Savanna
Forests 2019, 10(12), 1119; https://doi.org/10.3390/f10121119 (registering DOI) - 08 Dec 2019
Abstract
Deciduous dipterocarp forest (DDF) is the most extensive forest type in continental Southeast Asia, but across much of its range is functionally more similar to tropical savannas than tropical forests. We investigated water relations and drought responses of the four dominant tree species [...] Read more.
Deciduous dipterocarp forest (DDF) is the most extensive forest type in continental Southeast Asia, but across much of its range is functionally more similar to tropical savannas than tropical forests. We investigated water relations and drought responses of the four dominant tree species (two Shorea and two Dipterocarpus species) of the DDF in central Vietnam to determine how they responded to prolonged periods of drought stress. We quantified leaf water relations in nursery- and field-grown seedlings of the four species and conducted a dry-down experiment on 258 seedlings to study leaf water potential and morphological responses of the seedlings following the drought stress. The two Shorea and two Dipterocarpus species differed significantly in leaf water potential at turgor loss point and osmotic potential at full turgor, but they showed similar responses to drought stress. All species shed leaves and suffered from stem loss when exposed to water potentials lower than their turgor loss point (approximately −1.7 MPa for Dipterocarpus and −2.6 MPa for Shorea species). Upon rewatering, all species resprouted vigorously regardless of the degree of leaf or stem loss, resulting in only 2% whole-plant mortality rate. Our results suggest that none of the four deciduous dipterocarp species is drought tolerant in terms of their water relations; instead, they employ drought-adaptive strategies such as leaf shedding and vigorous resprouting. Given that all species showed similar drought avoidance and drought-adaptive strategies, it is unlikely that seasonal drought directly influences the patterns of species assembly in the DDF of Southeast Asia. Full article
(This article belongs to the Section Forest Ecophysiology and Biology)
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Open AccessReview
Methyltransferase Inhibitors: Competing with, or Exploiting the Bound Cofactor
Molecules 2019, 24(24), 4492; https://doi.org/10.3390/molecules24244492 (registering DOI) - 08 Dec 2019
Abstract
Protein methyltransferases (PMTs) are enzymes involved in epigenetic mechanisms, DNA repair, and other cellular machineries critical to cellular identity and function, and are an important target class in chemical biology and drug discovery. Central to the enzymatic reaction is the transfer of a [...] Read more.
Protein methyltransferases (PMTs) are enzymes involved in epigenetic mechanisms, DNA repair, and other cellular machineries critical to cellular identity and function, and are an important target class in chemical biology and drug discovery. Central to the enzymatic reaction is the transfer of a methyl group from the cofactor S-adenosylmethionine (SAM) to a substrate protein. Here we review how the essentiality of SAM for catalysis is exploited by chemical inhibitors. Occupying the cofactor binding pocket to compete with SAM can be hindered by the hydrophilic nature of this site, but structural studies of compounds now in the clinic revealed that inhibitors could either occupy juxtaposed pockets to overlap minimally, but sufficiently with the bound cofactor, or induce large conformational remodeling leading to a more druggable binding site. Rather than competing with the cofactor, other inhibitors compete with the substrate and rely on bound SAM, either to allosterically stabilize the substrate binding site, or for direct SAM-inhibitor interactions. Full article
(This article belongs to the Special Issue Design, Synthesis, and Biological Evaluation of Enzyme Inhibitors)
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Open AccessArticle
“What? That’s for Old People, that.” Home Adaptations, Ageing and Stigmatisation: A Qualitative Inquiry
Int. J. Environ. Res. Public Health 2019, 16(24), 4989; https://doi.org/10.3390/ijerph16244989 (registering DOI) - 08 Dec 2019
Abstract
Older people, even those living with long-term conditions or poor mobility, can be supported to live well at home, through adapting their home to meet changing need. Installing home adaptations, from grab rails to walk in shower rooms, is cost effective, may prevent [...] Read more.
Older people, even those living with long-term conditions or poor mobility, can be supported to live well at home, through adapting their home to meet changing need. Installing home adaptations, from grab rails to walk in shower rooms, is cost effective, may prevent falls, reduce social isolation and improve self confidence. Despite austerity cuts to public spending, the UK government increased home adaptations’ funding. However, not much is known about older people’s experiences and understanding of acquiring and living with home adaptations and uptake of home adaptations could be improved. Using wearable camera and face to face interview data, this qualitative study explored a diverse group of older people’s retrospective experiences (n = 30). Focus group discussions were also carried out with a wide range of professionals involved in the provision of home adaptations (n = 39). Findings suggest people may delay having adaptations, because of perceived stigmatising associations with decline and vulnerability. As delaying the installation of home adaptations until crisis point is known to reduce their effectiveness, such associations need to be challenged. Full article
(This article belongs to the Special Issue Advances in Housing and Healthy Ageing)
Open AccessArticle
Evaluating the Role of Iron-Rich (Mg,Fe)O in Ultralow Velocity Zones
Minerals 2019, 9(12), 762; https://doi.org/10.3390/min9120762 (registering DOI) - 08 Dec 2019
Abstract
The composition of ultralow velocity zones (ULVZs) remains an open question, despite advances in both seismology and experimental work. We investigate the hypothesis of iron-rich (Mg,Fe)O (magnesiowüstite) as a cause of ULVZ seismic signatures. We report new quasi-hydrostatic X-ray diffraction measurements to constrain [...] Read more.
The composition of ultralow velocity zones (ULVZs) remains an open question, despite advances in both seismology and experimental work. We investigate the hypothesis of iron-rich (Mg,Fe)O (magnesiowüstite) as a cause of ULVZ seismic signatures. We report new quasi-hydrostatic X-ray diffraction measurements to constrain the equation of state of (Mg0.06Fe0.94)O with fit parameters V0 = 9.860 ± 0.007 Å3, K0T = 155.3 ± 2.2 GPa, K0T = 3.79 ± 0.11, as well as synchrotron Mössbauer spectroscopy measurements to characterize the high-pressure magnetic and spin state of magnesiowüstite. We combine these results with information from previous studies to calculate the elastic behavior at core–mantle boundary conditions of magnesiowüstite, as well as coexisting bridgmanite and calcium silicate perovskite. Forward models of aggregate elastic properties are computed, and from these, we construct an inverse model to determine the proportions of magnesiowüstite that best reproduce ULVZ observations within estimated mutual uncertainties. We find that the presence of magnesiowüstite can explain ULVZ observations exhibiting 1:2 VP:VS reduction ratios relative to the Preliminary Reference Earth Model (PREM), as well as certain 1:3 VP:VS reductions within estimated uncertainty bounds. Our work quantifies the viability of compositionally distinct ULVZs containing magnesiowüstite and contributes to developing a framework for a methodical approach to evaluating ULVZ hypotheses. Full article
(This article belongs to the Special Issue Mineral Physics—In Memory of Orson Anderson)
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Open AccessArticle
Seasonal Variability in the Microbial Community and Pathogens in Wastewater Final Effluents
Water 2019, 11(12), 2586; https://doi.org/10.3390/w11122586 (registering DOI) - 08 Dec 2019
Abstract
Numerous bacteria, especially pathogens, exist in wastewater final effluents, which can lead to possible human health and ecological security risks when effluents are reused or discharged. However, the diversity, composition, and spatiotemporal dynamics of bacteria in wastewater final effluents remain poorly understood. In [...] Read more.
Numerous bacteria, especially pathogens, exist in wastewater final effluents, which can lead to possible human health and ecological security risks when effluents are reused or discharged. However, the diversity, composition, and spatiotemporal dynamics of bacteria in wastewater final effluents remain poorly understood. In this study, a comprehensive analysis of the microbial community and pathogens in wastewater final effluents was performed using high-throughput sequencing. The results revealed that wastewater final effluents in autumn exhibited the highest bacterial community richness and diversity, while those in winter exhibited the lowest. Bacteria in wastewater final effluents predominantly belonged to five phyla, in the order of Proteobacteria, Actinobacteria, Planctomycetes, Bacteroidetes, and Firmicutes. At the species level, there were 8~15 dominant species in the wastewater final effluent in each season, and Dokdonella immobilis, Rhizobium gallicum, Candidatus Flaviluna lacus, and Planctomyces limnophilus were the most dominant species in spring, summer, autumn, and winter, respectively. The seasonal variability in bacteria suggested that the microbial diversity and community in wastewater final effluents were mainly influenced by temperature, salinity, disinfection methods, and flocculants. Notably, pathogenic bacteria in wastewater effluents had both the highest relative abundance and species abundance in summer. Arcobacter spp., Legionella spp., and Mycobacterium spp. were the dominant pathogenic bacteria, and all pathogenic bacteria were mainly associated with dermatosis, enteropathies, septicemia, and pneumonia. Full article
(This article belongs to the Section Water Quality and Ecosystems)
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Open AccessArticle
Utilization of Crop Residue for Power Generation: The Case of Ukraine
Sustainability 2019, 11(24), 7004; https://doi.org/10.3390/su11247004 (registering DOI) - 08 Dec 2019
Abstract
Renewable energy is expected to play a significant role in power generation. The European Union, the USA, China, and others, are striving to limit the use of energy crop for energy production and to increase the use of crop residue both on the [...] Read more.
Renewable energy is expected to play a significant role in power generation. The European Union, the USA, China, and others, are striving to limit the use of energy crop for energy production and to increase the use of crop residue both on the field and for energy generation processes. Therefore, crop residue may become a major energy source, with Ukraine following this course. Currently in Ukraine, renewable power generation does not exceed 10% of total electricity production. Despite a highly developed agriculture sector, there are only a small number of biomass power plants which burn crop residues. To identify possibilities for renewable power generation, the quantity of crop residues, their energy potential, and potential electricity generation were appraised. Cluster analysis was used to identify regions with the highest electricity consumption and crop residue energy potential. The major crops (wheat, barley, rapeseed, sunflower, and soybean) were considered in this study. A national production of crop residue for energy production of 48.66 million tons was estimated for 2018. The availability of crop residues was analyzed taking into account the harvest, residue-to-crop ratio, and residue removal rate. The crop residue energy potential of Ukraine has been estimated at 774.46 PJ. Power generation technologies have been analyzed. This study clearly shows that crop residue may generate between 27 and 108 billion kWh of power. We have selected preferable regions for setting up crop residue power plants. The results may be useful for the development of energy policy and helpful for investors in considering power generation projects. Full article
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Open AccessArticle
Migration and Diffusion of Heavy Metal Cu from the Interior of Sediment during Wave-Induced Sediment Liquefaction Process
J. Mar. Sci. Eng. 2019, 7(12), 449; https://doi.org/10.3390/jmse7120449 (registering DOI) - 08 Dec 2019
Abstract
Sediments are an important sink for heavy metal pollutants on account of their strong adsorption capacity. Elevated content of Cu was observed in the Chengdao area of the Yellow River Delta, where the surface sediment is mainly silt and is prone to be [...] Read more.
Sediments are an important sink for heavy metal pollutants on account of their strong adsorption capacity. Elevated content of Cu was observed in the Chengdao area of the Yellow River Delta, where the surface sediment is mainly silt and is prone to be liquefied under hydrodynamic forces. The vertical transport of fine particles, along with pore water seepage, during the liquefaction process could promote the migration and diffusion of Cu from the interior of sediment. The present study involved a series of wave flume experiments to simulate the migration and diffusion of Cu from the interior of sediment in the subaqueous Yellow River Delta area under wave actions. The results indicated that sediment liquefaction significantly promoted the release of Cu from internal sediment to overlying water. The variations of Cu concentrations in the overlying water were opposite to the suspended sediment concentrations (SSCs). The sediment liquefaction caused high initial rises of SSCs, but led to a rapid decline of dissolved Cu concentration at the initial period of sediment liquefaction due to the adsorption by fine particles. Afterwards, the SSCs slightly increased and then gradually decreased. Meanwhile, the dissolved Cu concentration generally kept increasing under combined effects of intensively mix of sediment and overlying water, pore water seepage, and desorption. The dissolved Cu concentration in the overlying water during sediment liquefaction phase was 1.5–2.2 times that during the consolidation phase. Sediment liquefaction also caused vertical diffusion of Cu in sediment and the diffusion depth was in accordance with the liquefaction depth. The results of the present study may provide reference for the environmental management in the study area. Full article
(This article belongs to the Special Issue New Advances in Marine Engineering Geology)
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Open AccessArticle
Nanostructured Silver Coating as a Stationary Phase for Capillary Gas Chromatography
Molecules 2019, 24(24), 4491; https://doi.org/10.3390/molecules24244491 (registering DOI) - 08 Dec 2019
Abstract
A capillary column coated with nanostructured silver coating was fabricated for gas chromatography. The nanostructured silver coating, about 80–120 nm in thickness, was prepared as the stationary phase via silver mirror reaction, and was characterized by SEM and EDS. The column was evaluated [...] Read more.
A capillary column coated with nanostructured silver coating was fabricated for gas chromatography. The nanostructured silver coating, about 80–120 nm in thickness, was prepared as the stationary phase via silver mirror reaction, and was characterized by SEM and EDS. The column was evaluated using different types of model analytes, including n-alkanes, n-alcohols, benzenes, and Grob mixture. A baseline separation of ten n-alkanes on the silver column (15 m × 0.20 mm i.d.) was achieved within 3.5 min through the main hydrophobic mechanism. A mixture of six n-alcohols, or another mixture containing three butanol isomers and two octanol isomers, was separated well on the column. The column separated some benzenes containing benzene, toluene, ethylbenzene, p-xylene, o-xylene, styrene, benzaldehyde, and benzyl alcohol. A Grob mixture containing seven analytes was also separated successfully. Based on a multiple retention mechanism such as hydrophobic, dipole-dipole, and dipole-induced dipole interactions, the silver column achieved a good separation of twelve different types of compounds within 2.5 min. The column presented satisfactory separation repeatability with relative standard deviation of retention time between 0.073% and 0.591%. The results indicate that the silver column is promising for gas chromatographic separation. Full article
(This article belongs to the Section Analytical Chemistry)
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