► Graphitic carbon nitrides by CVD of melamine and uric acid on alumina. ► The building blocks of carbon nitrides are heptazine nuclei. ► Composite particles with alumina core and carbon nitride ...coating.
Graphitic carbon nitrides were synthesized starting from melamine and uric acid. Uric acid was chosen because it thermally decomposes, and reacts with melamine by condensation at temperatures in the range of 400–600
°C. The reagents were mixed with alumina and subsequently the samples were treated in an oven under nitrogen flux. Alumina favored the deposition of the graphitic carbon nitrides layers on the exposed surface. This method can be assimilated to an
in situ chemical vapor deposition (CVD). Infrared (IR) spectra, as well as X-ray diffraction (XRD) patterns, are in accordance with the formation of a graphitic carbon nitride with a structure based on heptazine blocks. These carbon nitrides exhibit poor crystallinity and a nanometric texture, as shown by transmission electron microscopy (TEM) analysis. The thermal degradation of the graphitic carbon nitride occurs through cyano group formation, and involves the bridging tertiary nitrogen and the bonded carbon, which belongs to the heptazine ring, causing the ring opening and the consequent network destruction as inferred by connecting the IR and X-ray photoelectron spectroscopy (XPS) results. This seems to be an easy and promising route to synthesize graphitic carbon nitrides. Our final material is a composite made of an alumina core covered by carbon nitride layers.
In recent years, nutmeg (
Houtt.) has attracted considerable attention in the field of phytochemistry due to its diverse array of bioactive compounds. However, the potential application of nutmeg as ...a biorational for crop protection has been insufficiently explored. This study investigated the constituents of a nutmeg hydroethanolic extract via gas chromatography-mass spectrometry and vibrational spectroscopy. The research explored the extract's activity against phytopathogenic fungi and oomycetes, elucidating its mechanism of action. The phytochemical profile revealed fatty acids (including tetradecanoic acid, 9-octadecenoic acid,
-hexadecanoic acid, dodecanoic acid, and octadecanoic acid), methoxyeugenol, and elemicin as the main constituents. Previously unreported phytochemicals included veratone, gelsevirine, and montanine. Significant radial growth inhibition of mycelia was observed against
, and especially against
. Mode of action investigation, involving
labeled positively with propidium iodide, and a mutant strain affected in ERG6, encoding sterol C-24 methyltransferase, suggested that the extract induces a necrotic type of death and targets ergosterol biosynthesis. The evidence presented underscores the potential of nutmeg as a source of new antimicrobial agents, showing particular promise against
.
Arsenic is one of the regulated hazard materials in the environment and a persistent pollutant creating environmental, agricultural and health issues and posing a serious risk to humans. In the ...present review, sources and mobility of As in various compartments of the environment (air, water, soil and sediment) around the World are comprehensively investigated, along with measures of health hazards. Multiple atomic spectrometric approaches have been applied for total and speciation analysis of As chemical species. The LoD values are basically under 1 μg L
−1
, which is sufficient for the analysis of As or its chemical species in environmental samples. Both natural and anthropogenic sources contributed to As in air, while fine particulate matter tends to have higher concentrations of arsenic and results in high concentrations of As up to a maximum of 1660 ng m
−3
in urban areas. Sources for As in natural waters (as dissolved or in particulate form) can be attributed to natural deposits, agricultural and industrial effluents, for which the maximum concentration of 2000 μg L
−1
was found in groundwater. Sources for As in soil can be the initial contents, fossil fuel burning products, industrial effluents, pesticides, and so on, with a maximum reported concentration up to 4600 mg kg
−1
. Sources for As in sediments can be attributed to their reservoirs, with a maximum reported concentration up to 2500 mg kg
−1
. It is notable that some reported concentrations of As in the environment are several times higher than permissible limits. However, many aspects of arsenic environmental chemistry including contamination of the environment, quantification, mobility, removal and health hazards are still unclear.
Contamination, mobility, sources, and exposure of arsenic (one of the regulated elements) in the environment are investigated and discussed comprehensively.
Despite extensive research on the chemical composition of elderberries and their numerous uses in pharmaceutical, beverage, and food production, there is still a lack of knowledge about
leaves and ...flowers' antimicrobial activity against plant pathogens. In this study, the phytoconstituents of their aqueous ammonia extracts were first characterized by infrared spectroscopy and gas chromatography-mass spectrometry. The major phytocompounds identified in the flower extract were octyl 2-methylpropanoate; 3,5-dihydroxy-6-methyl-2,3-dihydropyran-4-one; propyl malonic acid; adenine; and 1-methyl-2-piperidinemethanol. Concerning the leaf extract, 1,6-anhydro-β-D-glucopyranose; oleic acid; 2,1,3-benzothiadiazole; 2,3-dihydro-benzofuran; and 4-((1E)-3-hydroxy-1-propenyl)-2-methoxyphenol and other phenol derivatives were the main constituents. The potential of the extracts to act as bioprotectants was then investigated against three almond tree pathogens:
,
, and
. In vitro tests showed higher activity of the flower extract, with EC
values in the 241-984 μg·mL
range (depending on the pathogen) vs. 354-1322 μg·mL
for the leaf extract. In addition, the flower extract led to full protection against
at a dose of 1875 μg·mL
in ex situ tests on artificially-infected excised almond stems. These inhibitory concentrations were lower than those of commercial fungicides. These findings suggest that
aerial organs may be susceptible to valorization as an alternative to synthetic fungicides for the protection of this important crop.
Summary
Plant seeds are major sources of nutrients and bioactive compounds for human beings and vary across different locations. In addition, they are under used foods that could be a good complement ...for the daily nutrition of people. Therefore, the aim of this study was the analysis of different physical parameters, nutrients and bioactive compounds of 60 plant seeds belonging to 48 species and 9 families. The seeds were collected in 2016–2017 in the Raipur area, India (21.25°N 81.63°E), from three different locations. Fat, protein, starch, total polyphenols and mineral contents ranged from 0.7 to 44.2, 1.6 to 68.5, 11.3 to 84.0, 0.01 to 3.85 and 0.67 to 4.91 g/100 g (dry weight) respectively. Regarding physical properties, the heavier seeds were covered with thick testa over the range of 3.0 to 40% of the seed mass. Higher moisture and ash fractions for the starchy (cereal and pulses) and weed seeds were also found. The most abundant mineral elements in the seeds were P, S, K, Mg, Ca, Fe and Zn. Finally, it was calculated the contribution of the consumption of seeds to the daily macronutrients and micronutrients intake for Indian population, reaching up to 38, 13 and 25% for proteins, fat and carbohydrates respectively.
Indian seeds are a good source of nutrients, specially starch, minerals and phenolic compounds.
Solution-processed near-infrared organic light-emitting diodes (NIR-OLEDs) with structure glass/indium–tin oxide/poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate)/Er-complex/Ca/Al based on a ...novel Er(III) complex, Er(tfnb)3(bipy) (Htfnb = 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione and bipy = 2,2′-bipyridine) have been manufactured and their properties have been studied. A complete quenching of the organic ligand visible emission is shown, and only the sensitized 1.5 μm electroluminesce from Er(III) results. From the electrical characteristic we present the mobility dependence on applied voltage using a numerical model, comparing it to poly(9,9-dioctylfluorene), a commercial semiconducting polymer with optical properties close to those of the molecular ligands. The synthesis of the novel complex together with a detailed analysis of its structure elucidated by XRD, 1H NMR, Raman, and Fourier-transform infrared spectroscopies is presented. A wide-ranging characterization of its photophysical properties in terms of absorption and steady and transient photoluminescence is used to investigate the energy-transfer process from the organic ligand to the central Er(III) ion.
Throughout prehistoric times it was common to smear red pigment on the bodies of the dead. Iron oxide was the most common pigment, but other pigments were also used. In this work, two red‐stained ...bones from the megalithic tomb of El Moreco were characterized by SEM‐EDS, FTIR, and GC–MS. The results provide evidence for the usage of a pigment obtained from Rubia spp. This finding constitutes one of the oldest evidences of the use of madder red in Western Europe (IV‐III millennium BC) and, without ruling out other functions, suggests that it could have been used as a textile dye.
The cliff rose (
), like other halophytes, has a phenolics-based antioxidant system that allows it to grow in saline habitats. Provided that antioxidant properties are usually accompanied by ...antimicrobial activity, in this study we investigated the phytochemicals present in a hydromethanolic extract of
flowers and explored its antifungal potential. The main phytocompounds, identified by gas chromatography-mass spectrometry, were: hexadecanoic acid, octadecanoic acid, 9-octadecenoic acid, 3-(3,4-dihydroxy-phenyl)-acrylic acid ethyl ester, and benzeneacetaldehyde. The antifungal activity of the extract and its main constituents-alone and in combination with chitosan oligomers-was tested against six pathogenic taxa associated with soil-borne diseases of plant hosts in the family Cucurbitaceae:
,
f. sp.
,
,
,
, and
. In in vitro tests, EC
effective concentrations in the 166-865 μg·mL
range were obtained for the chitosan oligomers-
extract conjugate complexes, lower than those obtained for fosetyl-Al and azoxystrobin synthetic fungicides tested for comparison purposes, and even outperforming mancozeb against
. In ex situ tests against
conducted on artificially inoculated cucumber slices, full protection was achieved at a dose of 250 μg·mL
. Thus, the reported results support the valorization of
as a source of biorationals for Cucurbitaceae pathogens protection, suitable for both organic and conventional agriculture.
By-products from the wax production process from carnauba palm (leaves), from the extraction of oil from macauba seeds (endocarp) and from pine nut production (shell) have been assessed for activated ...carbon production, using H3PO4 or CaCl2 for their chemical activation. The resulting activated charcoals have been thoroughly characterized by elemental and thermal analysis, X-ray diffraction, infrared spectroscopy, electron scanning microscopy and N2 adsorption behavior. Subsequently, their adsorption capacity for the removal of rhodamine B (RhB) from aqueous solutions has been evaluated by studying different parameters: contact time, pH, adsorbent dose, initial dye concentration and solution temperature. The adsorption of RhB followed Freundlich's model in all cases. Kinetic studies indicate that the pseudo-second order model can be used for describing the dynamics of the adsorption process. Thermodynamic parameters have also been evaluated, indicating its endothermic and spontaneous nature. Finally, a preliminary analysis of the impact of cellulose content in the carbon precursor materials has been conducted, by using a mixture of native cellulose with one of the lignocellulosic materials.
•Activated carbons have been obtained from carnauba, macauba and pine nut wastes.•Effect of contact time, pH, temperature, adsorbent and dye dose has been assessed.•RhB removal up to 99.85% was attained for carnauba palm leaves-based carbon.•CaCl2 activation leads to better adsorptive capacities than H3PO4 activation.•Dye removal markedly improves when cellulose content is artificially increased.
is a singular halophyte that has been shown to have anti-inflammatory, antioxidant, and allelopathic properties. In the work presented herein, we have characterized its inflorescences hydromethanolic ...extract and assessed its antifungal activity for the pre- and postharvest management of tomato crop diseases. Gas chromatography-mass spectrometry characterization of the extract showed that 4-ethenyl-1,3-benzenediol, 2,3-dihydro-benzofuran, quinic acid, 3,5-dihydroxy-6,7,8-trimethoxy-2-phenyl-4H-1-benzopyran-4-one, 1,6-anhydro-
-D-glucopyranose, catechol, scopoletin, and maltol were the main constituents. The co-occurrence of pyranones, benzenediols, and quinic acids as phytoconstituents of
extract resulted in promising in vitro minimum inhibitory concentrations of 500, 375, 500, 187.5, 187.5, and 375 μg·mL
against mycelia of
,
f. sp.
, and
, respectively. Further, to assess the potential of
inflorescence extract for postharvest tomato crop protection, ex situ tests were conducted against
, obtaining high protection at a dose of 750 μg·mL
. Taking into consideration that the demonstrated activity is among the highest reported to date for plant extracts and comparable to that of the synthetic fungicides tested as positive controls,
inflorescence extract may be put forward as a promising biorational and may deserve further testing in field-scale studies.
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