Search

Broccoli has gained popularity as a highly consumed vegetable due to its nutritional and health properties. This study aimed to evaluate the composition profile and the antioxidant capacity of a hydrophilic extract derived from broccoli byproducts, as well as its influence on redox biology, Alzheimer's disease markers, and aging in the Caenorhabditis elegans model. The presence of glucosinolate was observed and antioxidant capacity was demonstrated both in vitro and in vivo . The in vitro acetylcholinesterase inhibitory capacity was quantified, and the treatment ameliorated the amyloid-β- and tau-induced proteotoxicity in transgenic strains via SOD-3 and SKN-1, respectively, and HSP-16.2 for both parameters. Furthermore, a preliminary study on aging indicated that the extract effectively reduced reactive oxygen species levels in aged worms and extended their lifespan. Utilizing broccoli byproducts for nutraceutical or functional foods could manage vegetable processing waste, enhancing productivity and sustainability while providing significant health benefits.

Cenotes are habitats with unique physical, chemical, and biological features. Unexplored microorganisms from these sinkholes represent a potential source of bioactive molecules. Thus, a series of cultivable fungi ( Aspergillus spp. NCA257, NCA264, and NCA276, Stachybotrys sp. NCA252, and Cladosporium sp. NCA273) isolated from the cenote Tza Itzá were subjected to chemical, coculture, and metabolomic analyses. Nineteen compounds were obtained and tested for their antimicrobial potential against ESKAPE pathogens, Mycobacterium tuberculosis , and nontuberculous mycobacteria. In particular, phenylspirodrimanes from Stachybotrys sp. NCA252 showed significant activity against MRSA, MSSA, and mycobacterial strains. On the other hand, the absolute configuration of the new compound 17-deoxy-aspergillin PZ ( 1 ) isolated from Aspergillus sp. NCA276 was established via single-crystal X-ray crystallography. Also, the chemical analysis of the cocultures between Aspergillus and Cladosporium strains revealed the production of metabolites that were not present or were barely detected in the monocultures. Finally, molecular networking analysis of the LC-MS-MS/MS data for each fungus was used as a tool for the annotation of additional compounds, increasing the chemical knowledge on the corresponding fungal strains. Overall, this is the first systematic chemical study on fungi isolated from a sinkhole in Mexico., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Hydrotalcites are an important class of layered materials, displaying ion-exchange, adsorption, and base catalytic properties. The crystallization kinetics for hydrotalcites are however hardly available. Nevertheless, as their reconstruction from the oxides (also called as "memory effect") is considered a synthesis route, this can be used to study the crystallization phenomena. This note looks at the reconstruction kinetics of a Mg-Al hydrotalcite using previously reported kinetic expressions. It was found that high temperature is beneficial if the process is controlled by nucleation. The temperature effect is less obvious when the process reaches a diffusional control regime. For example, temperature is beneficial to shorten the processing time in a nucleation-regime conversion (e.g., 40%). However, to achieve a high conversion (e.g., 98-99%), an intermediate temperature shows the optimal condition, i.e., shortest processing time. The work shows useful side effects of diffusional control. It also highlights the importance of obtaining the kinetics over the entire range for process optimization and, finally, emphasizes that both parameters in the Avrami-Erofe'ev model impact the time required to achieve a given conversion. Directions for further studies to understand the kinetic-process relationships have been highlighted., Competing Interests: The authors declare no competing financial interest., (© 2021 American Chemical Society.)

The health benefits of extra virgin olive oil (EVOO) are associated to its fatty acids profile (with predominance of oleic acid) and to the minor components that include phenols, among others. Phenols are responsible for the only health claim of olive oil reported in the Commission Regulation (EU) 432/2012. Here, we have applied a liquid chromatography-tandem mass spectrometry method to determine the most abundant phenols included in the health claim (with special emphasis on secoiridoids) in 1239 EVOO samples produced in two consecutive agronomical seasons. The predominant cultivars in Spain ("Picual", "Arbequina", "Hojiblanca", and "Cornicabra") were evaluated. We also studied the influence of harvesting date and orchard location on the EVOO phenolic concentration. A great variability in phenolic content, from 1 to 2850 mg/kg, was found in these EVOOs, and not all of them (4.6 and 23.1% in the two seasons) reported a concentration above 250 mg/kg to certify the health claim.

The development of self-healing rubbers is currently under investigation as a strategy to promote their reuse and, hence, reduce their waste. However, autonomous, multicycle self-healing rubbers with good mechanical properties have so far proven difficult to achieve. Here, mechanically robust composites based on epoxidized natural rubber (ENR) and thermally reduced graphene oxide (TRGO) were successfully designed and prepared with a high healing efficiency of up to 85% at room temperature without applying external stimuli. The incorporation of TRGO not only improves the mechanical performance in more than 100% in relation to pristine ENR but also promotes the hydrogen bonding interactions with the rubber. This leads to a homogenous dispersion of TRGO within the ENR matrix, which further increases its self-healing capability., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)

An ab initio study of the interaction of O 2 , the most abundant radical and oxidant species in the atmosphere, with a Cu 5 cluster, a new generation atomic metal catalyst, is presented. The open-shell nature of the reactant species is properly accounted for by using the multireference perturbation theory, allowing the experimentally confirmed resistivity of Cu 5 clusters toward oxidation to be investigated. Approximate reaction pathways for the transition from physisorption to chemisorption are calculated for the interaction of O 2 with quasi-iso-energetic trapezoidal planar and trigonal bipyramidal structures. Within the multireference approach, the transition barrier for O 2 activation can be interpreted as an avoided crossing between adiabatic states (neutral and ionic), which provides new insights into the charge-transfer process and gives better estimates for this hard to localize and therefore often neglected first intermediate state. For Cu 5 arranged in a bipyramidal structure, the O-O bond cleavage is confirmed as the rate-determining step. However, for planar Cu 5 , the high energy barrier for O 2 activation, related to a very pronounced avoided crossing when going from physisorption to chemisorption, determines the reactivity in this case., Competing Interests: The authors declare no competing financial interest.

Subnanometric noble metal clusters, composed by only a few atoms, behave like molecular entities and display magnetic, luminescent and catalytic activities. However, noncovalent interactions of molecular metal clusters, lacking of any ligand or surfactant, have not been seen at work. Theoretically attractive and experimentally discernible, van der Waals forces and noncovalent interactions at the metal/organic interfaces will be crucial to understand and develop the next generation of hybrid nanomaterials. Here, we present experimental and theoretical evidence of noncovalent interactions between subnanometric metal (0) silver clusters and aromatic rings and their application in the preparation of 1D self-assembled hybrid architectures with ditopic peptide nanotubes. Atomic force microscopy, fluorescence experiments, circular dichroism and computational simulations verified the occurrence of these interactions in the clean and mild formation of a novel peptide nanotube and metal cluster hybrid material. The findings reported here confirmed the sensitivity of silver metal clusters of small atomicity toward noncovalent interactions, a concept that could find multiple applications in nanotechnology. We conclude that induced supramolecular forces are optimal candidates for the precise spatial positioning and properties modulation of molecular metal clusters. The reported results herein outline and generalize the possibilities that noncovalent interactions will have in this emerging field.

We present a theoretical model to predict the atomic structure of Au/Pt nanoparticles synthesized in microemulsions. Excellent concordance with the experimental results shows that the structure of the nanoparticles can be controlled at subnanometer resolution simply by changing the reactant concentration. The results of this study not only offer a better understanding of the complex mechanisms governing reactions in microemulsions, but open up a simple new way to synthesize bimetallic nanoparticles with ad hoc controlled nanostructures.

Discrimination among the types of feeding regimes for Iberian pigs is currently a highly demanded challenge by the Iberian pig sector. In the present research, discrimination among feeding regimes has been achieved by the combination of two analytical methods (based on FAMEs analysis by GC-FID and determination of δ(13)C by IRMS) previously used independently without success. In the present study, 80 samples of adipose tissue from Iberian pigs subjected to four different feedings were analyzed. The study of the variables more influenced by the feeding regime has allowed us to configure panels of markers with predictive power for the studied feedings by multivariate ROC analysis. The results provided values of specificity and sensitivity higher than 85% in most cases. The statistical combination of results from different analytical methods could be the key to develop models for the correct discrimination of Iberian pigs according to the feeding regime.

H2 production by water splitting is hindered mainly by the lack of low-cost and efficient photocatalysts. Here we show that sub-nanometric silver clusters can catalyze the anisotropic growth of gold nanostructures by preferential adsorption at certain crystal planes of Au seeds, with the result that the final nanostructure can be tuned via the cluster/seed ratio. Such semiconducting Ag clusters are extremely stable and retain their electronic structure even after adsorption at the tips of Au nanorods, enabling various photocatalytic experiments, such as oxygen evolution from basic solutions. In the absence of electron scavengers, UV irradiation generates photoelectrons, which are stored within the nanorods, increasing their Au Fermi level up to the redox pinning limit at 0 V (RHE), where hydrogen evolution occurs with an estimated high efficiency of 10%. This illustrates the considerable potential of very small zerovalent, nonmetallic clusters as novel atomic-level photocatalysts.

Gold atomic clusters of only two and three atoms were prepared by a simple electrochemical technique based on the anodic dissolution of a gold electrode in the presence of PVP, and subsequent electroreduction of the Au-PVP complexes. These clusters show stable photoluminescent and magnetic properties, which make them the smallest and most elemental gold (0) building blocks in nature (after atoms) bringing new possibilities to construct novel nano/microstructures with large potential interest in biomedicine, catalysis, and so forth.

Chiral alpha-silylsulfinamides, prepared by the treatment of an alkyldiphenylsilane with lithium followed by its addition to a sulfinimine, can be applied to the synthesis of 1,3-azasilaheterocycles as derivatives of cyclic alkaloids. This synthetic route, which involves intramolecular substitution of an amino alcohol or cyclization of an amino acid promoted by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), represents a convenient means for accessing these silicon-containing heterocycles.

Silver atomic quantum clusters (AgAQCs), with two or three silver atoms, show electrocatalytic activities that are not found in nanoparticles or in bulk silver. AgAQCs supported on glassy carbon electrodes oxidize ethanol and other alcohols in macroscopic electrochemical cells in acidic and basic media. This electrocatalysis occurs at very low potentials (from approximately +200 mV vs RHE), at physiological pH, and at ethanol concentrations that are found in alcoholic patients. When mammalian cells are co-exposed to ethanol and AgAQCs, alcohol-induced alterations such as rounded cell morphology, disorganization of the actin cytoskeleton, and activation of caspase-3 are all prevented. This cytoprotective effect of AgAQCs is also observed in primary cultures of newborn rat astrocytes exposed to ethanol, which is a cellular model of fetal alcohol syndrome. AgAQCs oxidize ethanol from the culture medium only when ethanol and AgAQCs are added to cells simultaneously, which suggests that cytoprotection by AgAQCs is provided by the ethanol electro-oxidation mediated by the combined action of AgAQCs and cells. Overall, these findings not only show that AgAQCs are efficient electrocatalysts at physiological pH and prevent ethanol toxicity in cultured mammalian cells, but also suggest that AgAQCs could be used to modify redox reactions and in this way promote or inhibit biological reactions.

We report the effect of topotactic replacement of Na(+) by H(3)O(+) in Na(0.5)CoO(2). Hydronium ions keep the Co oxidation state constant, increasing the interlayer distance. The result is a progressive destruction of the spin density wave characteristic of half-doped Na(x)CoO(2) and ultimately the induction of superconductivity. This implies that superconductivity occurs closer to Co(3+)/Co(4+) approximately = 1 than previously thought and that its development competes with the development of the magnetic phase.

We report evidence of the formation of small atomic copper clusters, Cu(n), by the microemulsion technique, and how their size can be controlled by adjusting the percentage of the reducing agent used. Copper clusters were characterized by UV-visible spectrophotometry and atomic force microscopy. Photoluminescent copper clusters, Cu(n), with n less, similar 13, can be obtained using very low percentages of the reducing agent (<10% of the stochiometric amount). Photoluminescent clusters disappear for larger percentages of reducing agent, giving rise to larger copper clusters (0.8-2.0 nm), showing a red-shift of their UV-visible absorption bands as they grow in size. Finally, by using near stoichiometric amounts, nanoparticles of 2.9 +/- 1.1 nm in size, displaying the characteristic plasmon band, can be obtained.

The phasing out of leaded gasoline in many countries around the world at the end of the last millennium has resulted in a complex mixture of lead sources in the atmosphere. Recent studies suggest that coal combustion has become an important source of Pb in aerosols in urban and remote areas. Here, we report lead concentration and isotopic composition for 59 coal samples representing major coal deposits worldwide in an attempt to characterize this potential source. The average concentration in these coals is 35 microg Pb g(-1), with the highest values in coals from Spain and Peru and the lowest in coals from Australia and North America. The 206Pb/207Pb isotope ratios range between 1.15 and 1.24, with less radiogenic Pb in coals from Europe and Asia compared to South and North America. Comparing the Pb isotopic signatures of coals from this and previous studies with those published for Northern and Southern Hemisphere aerosols, we hypothesize that coal combustion might now be an important Pb source in China, the eastern U.S., and to some extent, in Europe but not as yet in other regions including South Africa, South America, and western U.S. This supports the notion that "old Pb pollution" from leaded gasoline reemitted into the atmosphere or long-range transport (i.e., from China to the western U.S.) is important. Comparing the isotope ratios of the coals, the age of the deposits, and Pb isotope evolution models for the major geochemical reservoirs suggests that the PbIC in coals is strongly influenced by the depositional coal forming environment.

Hierarchical aggregates of gold nanoparticles (NPs) on different length scales were in situ generated at the surface of a bridged silsesquioxane during the process of film formation by polycondensation and solvent evaporation. A precursor of a bridged silsesquioxane based on the reaction product of (glycidoxypropyl)trimethoxysilane (2 mol) with dodecylamine (1 mol) was hydrolytically condensed in a THF solution at room temperature in the presence of formic acid, water, and variable amounts of dodecanethiol-stabilized gold NPs (average diameter of 2 nm). The initial compatibility of the precursor with gold NPs was achieved by the presence of dodecyl chains in both components. Phase separation of gold NPs accompanied by partitioning to the air-polymer interface took place driven by the polycondensation reaction and solvent evaporation. A hierarchical organization of gold NPs in the structures generated at the air-polymer interface was observed. Small body-centered cubic (bcc) crystals of about 20 nm diameter were formed in the first step, in which the 2 nm gold NPs kept their individuality (high-resolution transmission electron microscopy, field emission scanning electron microscopy, and small-angle X-ray diffraction). In the second step, bcc crystals aggregated, forming compact micrometer-sized spherical particles. Under particular evaporation rates a third step of the self-assembly process was observed where micrometer-sized particles formed fractal structures. Increasing the initial concentration of gold NPs in the formulation led to more compact fractal structures in agreement with theoretical simulations. The surface percolation of NPs in fractal structures can be the basis of useful applications.

Small atomic gold clusters in solution, Au n , stabilized by tetrabutyl ammonium bromide (TBABr), have been synthesized by a simple electrochemical technique, based on the anodic dissolution of a gold electrode in the presence of TBABr salt, and using acetronitrile as solvent. The presence of clusters in the range Au3-Au11 were detected by MALDI-TOF spectroscopy, and further characterized by UV-vis absorption spectroscopy, TEM, AFM, X-ray diffraction, and cyclic voltammetry. Clusters display a semiconductor behavior with a band edge of approximately 2.5 eV. We report here their extraordinarily high electrocatalytic activity toward the O2 reduction reaction in acid solutions, which can explain Zhang's results, showing that a four-electron mechanism seems to occur because of the facile reduction of H2O2 on gold clusters compared to bulk gold or larger gold nanoparticles.

Ribbon-like and branched gold nano- and microstructures were produced by simple heating of diluted aqueous solutions of poly(vinylpyrrolidone) (PVP) and HAuCl4. The reaction was carried out in a one-pot, one-step process at mild temperatures. Modification of the synthesis variables allowed the obtaining of structures with different sizes and branching degrees which formed stable hydrosols with characteristic colors. A mechanism for the growth of the crystals was proposed, based on the aggregation of metal units followed by reorientation and attachment processes facilitated by the presence of low concentrations of the polymer. These anisotropic structures were used to obtain large-area porous coatings on metallic, plastic, and glass substrates and to synthesize homogeneous polymer composites. The resulting gold-modified materials showed an important increase of absorption in the near-infrared (NIR) region of the electromagnetic spectrum, which could find interesting applications in the development of NIR-absorbing filters and coatings.

Synthesis of gold and silver hydrosols was carried out in a one-step process by reduction of aqueous solutions of metal salts using poly(N-vinyl-2-pyrrolidone) (PVP). Both kinds of metal nanoparticles were obtained without the addition of any other reducing agent, at low temperatures and using water as the synthesis solvent. Shape, size, and optical properties of the particles could be tuned by changing the employed PVP/metal salt ratio. It is proposed that PVP acts as the reducing agent suffering a partial degradation during the nanoparticles synthesis. Two possible mechanisms are proposed to explain the reduction step: direct hydrogen abstraction induced by the metal ion and/or reducing action of macroradicals formed during degradation of the polymer. Initial formation of the macroradicals might be associated with the metal-accelerated decomposition of low amounts of peroxides present in the commercial polymer.

Arsenic and selenium compounds may be emitted to the environment during coal conversion processes, although some compounds are retained in the fly ashes, in different proportions depending on the characteristics of the ashes and process conditions. The possibility of optimizing the conditions to achieve better trace element retention appears to be an attractive, economical option for reducing toxic emissions. This approach requires a good knowledge of fly ash characteristics and a thorough understanding of the capture mechanism involved in the retention. In this work the ability of two fly ashes, one produced in pulverized coal combustion and the other in fluidized bed combustion, to retain arsenic and selenium compounds from the gas phase in coal combustion and coal gasification atmospheres was investigated. To explore the possible simultaneous retention of mercury, the influence of the unburned coal particle content was also evaluated. Retention capacities between 2 and 22 mg g(-1) were obtained under different conditions. The unburned coal particle content in the fly ash samples does not significantly modify retention capacities.

Large colloidal environmentally stable silica-coated cobalt particles were synthesized by combining the sodium borohydride reduction in aqueous solution and the Stöber method. Low size polydisperse cobalt spheres with an average size of 95 nm were synthesized by using a borohydride reduction method and were subsequently coated with a thin layer of silica by means of hydrolysis and condensation of tetraethylorothosilicate (TEOS) in an aqueous/ethanolic solution. The large uniform cobalt spheres consist of smaller metallic Co clusters, explaining the superparamagnetic behavior of the spheres. The particles were investigated by transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM).

The formation of Ag nanoparticles by electrochemical techniques has been investigated through a time-resolved UV-vis spectroscopy study. The formation of Ag(4)(2+) clusters is suggested as the main precursors to the particle formation. The mechanism also considers the electrodeposition which occurs as a parallel process in the electrochemical particle formation. Experiments at different current densities show that the electrodeposition is more important at low current densities. From the fittings of the change of the plasmon (lambda approximately 430 nm) and the cluster (lambda = 250 nm) bands to the proposed mechanism, the kinetic constants of the formation and disappearance of the Ag(4)(2+) cluster are derived. The kinetic fittings also allowed an estimation of the Ag(4)(2+) cluster extinction coefficient (epsilon(250) = 1.0 x 10(4) M(-1) cm(-1)). It is observed that the plasmon bandwidth (fwhm) follows the theoretical predicted 1/R law only for particles with sizes d approximately >3 nm, but the law is broken for the smallest particles (d < 2.5 nm). The break is associated with the existence of single-electron (SE) transitions which are activated by the plasmon decay for the smallest nanoparticles. From the broken 1/R law, a limit relaxation time of about 4 fs is derived for the plasmon deactivation. Below this limit, the plasmon seems to decay mainly through a nonradiative channel with the formation of electron-hole (e-h) pairs. By comparison of the 1/R broken law with other literature results, it is concluded that large interactions of the Ag nanoparticles with the used capping molecule (tetrabutylammonium acetate) facilitate the e-h plasmon deactivation.

The phase behavior of a mixture of poly(isoprene)-poly(oxyethylene) diblock copolymer (PI-PEO or C250EO70) and poly(oxyethylene) surfactant (C12EO3, C12EO5, C12EO6, C12EO7, and C12EO9) in water was investigated by phase study, small-angle X-ray scattering, and dynamic light scattering (DLS). The copolymer is not soluble in surfactant micellar cubic (I1), hexagonal (H1), and lamellar (Lalpha) liquid crystals, whereas an isotropic copolymer fluid phase coexists with these liquid crystals. Although the PI-PEO is relatively lipophilic, it increases the cloud temperatures of C12EO3-9 aqueous solutions at a relatively high PI-PEO content in the mixture. Most probably, in the copolymer-rich region, PI-PEO and C12EOn form a spherical composite micelle in which surfactant molecules are located at the interface and the PI chains form an oil pool inside. In the C12EO5/ and C12EO6/PI-PEO systems, one kind of micelles is produced in the wide range of mixing fraction, although macroscopic phase separation was observed within a few days after the sample preparation. On the other hand, small surfactant micelles coexist with copolymer giant micelles in C12EO7/ and C12EO9/PI-PEO aqueous solutions in the surfactant-rich region. The micellar shape and size are calculated using simple geometrical relations and compared with DLS data. Consequently, a large PI-PEO molecule is not soluble in surfactant bilayers (Lalpha phase), infinitely long rod micelles (H1 phase), and spherical micelles (I1 phase or hydrophilic spherical micelles) as a result of the packing constraint of the large PI chain. However, the copolymer is soluble in surfactant rod micelles (C12EO5 and C12EO6) because a rod-sphere transition of the surfactant micelles takes place and the long PI chains are incorporated inside the large spherical micelles.