The three lowest spin states (S = 0,1,2) of 12 representative Na13+ isomers have been estudied using both, KS‐DFT via three hybrid density functionals, and benchmark multireference CASSCF and CASPT2 ...methods with a couple of Dunning's correlation consistent basis sets. CASSCF(12,12) geometry optimizations were carried out. Since 12 electrons in 12 active orbitals span the chemically‐significant complete valence space, the results of the present study provide benchmarks for Na13+. The CASPT2(12,12)/cc‐pVTZ* lowest energy structures are three nearly degenerate singlets (S = 0): an isomer formed from two pentagonal bipyramids fused together (PBPb), a capped centered‐squared antiprism CSAP‐(1,3) and an optimum tetrahedral OPTET(II) structure, the last two lying 0.88 and 1.63 kcal/mol above the first, respectively. The lowest triplet (S = 1) and quintet (S = 2) states lie 4.33 and 3.77 kcal/mol above the singlet global minimum, respectively. The latter is a deformed icosahedron while the former is a CSAP‐(1,3). The flatness of the potential energy surface of this cluster suggests a rather strong dynamical character at finite temperature. Prediction of the lowest energy structures and electronic properties is crucially sensitive both to non‐dynamical and dynamical electron correlation treatment. The CASPT2 vertical ionization energy is 3.66 eV, in excellent agreement with the 3.6 ± 0.1 eV experimental figure. All the isomers are found to have a strong multireference character, thus making KS density functional theory fundamentally inappropriate for these systems. Only large multiconfigurational CASSCF wavefunctions provide a reliable zeroth‐order description; then the dynamic correlation effects must be properly taken into account for a truly accurate account of the structural and energetic features of alkali‐metal clusters.
Hybrid DFT and benchmark multireference CASSCF+CASPT2, studies of the three lowest spin states of the Na$_{13}^+$ cluster are presented in order to determine their optimal structures, their energetic hierarchy, and the magnetic nature of the ground state. A new and unforeseen lowest energy singlet structure is found. The CASPT2(12,12)/cc‐pVTZ* lowest energy structures are three nearly degenerate singlet states (S=0).
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BFBNIB, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
This paper reports an Alkali-Activated Materials (AAM) using two different precursors, metakaolin and a metallurgical slag with photocatalytic zinc oxide nanoparticles, as novel photocatalytic ...composites. The photodegradation performance of the composites using methylene blue (MB) dye as a wastewater model was investigated by ultraviolet radiations (UV-vis) spectroscopy. Adsorption in dark conditions and photodegradation under UV irradiation are the mechanisms for removing MB dye. The pseudo-first-order kinetic and pseudo-second-order kinetic models were employed, and the experimental data agreed with the pseudo-second-order model in both cases with UV and without UV irradiations. As new photocatalytic materials, these composites offer an alternative for environmental applications.
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Mexico has an extensive diversity of plants used for medicinal purposes. Green synthesis of gold nanoparticles (AuNPs) with medicinal plants has attracted significant attention because of advantages ...like ease, cost-effectiveness, eco-friendly, and rapid synthesis. This article presents the antioxidant activity and the ability to synthesize AuNPs of the aqueous and ethanolic extracts of Tagetes erecta L flowers (marigold) and Hibiscus sabdariffa L (Rosell) flowers. The synthesized AuNPs were characterized using UV–Vis spectroscopy, Scanning transmission electron microscopy (STEM), TGA analysis, FTIR, XDR, and a stability study. UV–Vis spectrum shows the surface plasmon resonance peak (SPR) around 500–580 nm. STEM images showed a spherical, triangular, and hexagonal morphology with diameters between 11.48 and 43.93 nm for aqueous extracts and 9.22 and 11.59 for ethanolic extracts of T. erecta and H. sabdariffa, respectively. TGA and FTIR analysis revealed that organic compounds present in extracts capped the surface of AuNPs. Characteristics and stability of green AuNPs were compared with chemical synthesis, observing that green AuNPs present lower diameters and better stability related to the capping compounds.
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•The antioxidant activity of extracts is related to their ability to synthesize AuNPs.•Phenolic compounds act as reducing and capping agents on the surface of AuNPs.•Ethanolic extracts synthesized AuNPs with lower diameters.•Green AuNPs present better stability compared with chemical synthesis.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Gold nanoparticles (AuNPs) are essential metal nanoparticles, and they have much application in different areas such as bio-imaging, medical therapy, enzyme assays and the environment. Various ...physical and chemical methods have been used for the synthesis of AuNPs. However the disadvantage of most of them is to generate a large number of by-products that are dangerous, in this sense, green synthesis with plant extracts has become one of the preferred methods for the development of these materials because it produces particles with high bioavailability and reduces the use of toxic chemicals. In addition to presenting unique characteristics of biocompatibility, large surface area, and high dispersion, they have been used to treat different types of cancer, such as colon cancer. This review presents the various methods for synthesizing gold nanoparticles and their application in cancer therapy, focusing on the green synthesis of gold nanoparticles and their specific colon cancer application.
Gold nanoparticles (AuNPs) are promising nanomaterials exhibiting anti-cancer effects. Green AuNPs synthesis using plant extracts can be used to achieve stable and beneficial nanoparticles due to ...their content of bioactive compounds. This research aimed to synthesize and evaluate the antiproliferative and caspase-3 activity induction of green AuNPs synthesized with common mullein (V. thapsus) flowers (AuNPsME) and castor bean (R. communis) leaves (AuNPsCE) ethanolic extracts in human HT29 and SW480 colorectal cancer cells. Their effect was compared with chemically synthesized AuNPs (AuNPsCS). The extracts mainly contained p-coumaric acid (71.88–79.93 µg/g), ferulic acid (19.07–310.71 µg/g), and rutin (8.14–13.31 µg/g). The obtained nanoparticles presented typical FT-IR bands confirming the inclusion of polyphenols from V. thapsus and R. communis and spherical/quasi-spherical morphologies with diameters in the 20.06–37.14 nm range. The nanoparticles (20–200 µg/mL) showed antiproliferative effects in both cell lines, with AuNPsCE being the most potent (IC50 HT29: 110.10 and IC50SW480: 64.57 µg/mL). The AuNPsCS showed the lowest intracellular reactive oxygen species (ROS) generation in SW480 cells. All treatments induced caspase 3/7 activity to a similar or greater extent than 30 mM H2O2-treated cells. Results indicated the suitability of V. thapsus and R. communis extracts to synthesize AuNPs, displaying a stronger antiproliferative effect than AuNPsCS.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Traditional medicine in Latin America and mainly in Mexico represents an essential alternative for treating different diseases. The use of plants as medicine is the product of a rich cultural ...tradition of the indigenous peoples, in which a great variety of species are used for the treatment of gastrointestinal, respiratory, and mental diseases and some other sicknesses; the therapeutic efficacy that they possess is due to the properties that derive from the active ingredients of plants principally antioxidants, such as phenolic compounds, flavonoids, terpenes, and tannins. An antioxidant is a substance that, at low concentrations, delays or prevents substrate oxidation through the exchange of electrons. Different methods are used to determine the antioxidant activity and the most commonly used are described in the review. Cancer is a disease in which some cells multiply uncontrollably and spread to other parts of the body, a process known as metastasis. These cells can lead to the formation of tumors, which are lumps of tissue that can be cancerous (malignant) or noncancerous (benign). Generally, the treatment of this disease consists of surgery, radiotherapy, or chemotherapy, which have side effects that decrease the quality of life of patients, so new treatments, focusing on natural resources such as plants, can be developed. This review aims to gather scientific evidence on the antioxidant compounds present in plants used in traditional Mexican medicine, specifically as antitumor treatment in the most common cancer types worldwide (e.g., breast, liver, and colorectal cancer).
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The SiO2 particles system is one of the most common ways to protect colloidal metal systems, such as gold nanoparticles, from aggregation and activity loss due to their high chemical stability and ...low reactivity. In this study, silica green gold nanoparticles (AuNPs synthesized with mullein extract) were fabricated using two different sol–gel methods. The nanoparticles were characterized by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), Fourier Transformed Infrared (FTIR), and the antibacterial activity against pathogens (Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella enterica). Synthesis-1 nanoparticles had a kidney-shaped form and uniform distribution, while synthesis-2 nanoparticles had a spherical and non-uniform form. Characterization showed that temperature is an important factor in the distribution of AuNPs in silica; a decrease allowed the formation of Janus-type, and an increase showed a higher concentration of gold in energy-dispersive spectroscopy (EDS) analysis. Overall, similar bands of the two synthesis silica nanoparticles were observed in FTIR, while XRD spectra showed differences in the preferential growth in AuNPs depending on the synthesis. Higher antibacterial activity was observed against S. aureus, which was followed by L. monocytogenes. No differences were observed in the antibacterial activity between the two different sol–gel methods.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
In this investigation, HAp powders were synthesized using the wet chemical precipitation technique. The temperature of the heat treatment (80 °C, 120 °C, and 160 °C) and the addition of glutamic acid ...were the considered process parameters. After the reaction between the precursors calcium nitrate Ca(NO3)2 and ammonium phosphate (NH4)H2PO4, decantation of the residue, drying, and finally, heat treatment of the residue were done sequentially. X-ray diffraction (XRD) analysis, scanning electron microscope (SEM) observations, and X-ray fluorescence (XRF) analysis were carried out to characterize the synthesized HAp powders. It was found that at a high heat treatment temperature plus the addition of glutamic acid are suitable process parameters to acquire uniform HAp powders with plate morphology and fibers with an average particle size of ∼100–200 µm. The Ca/P ratio obtained was like the hydroxyapatite present in the bones in the order of 1.72. This situation can be indicated as an essential advantage in the biocompatibility of the synthesized material. The use of glutamic acid suggests crystal growth in a preferential direction as reported in our previous work. The manufacture of hydroxyapatite, especially in powder, is of great interest in developing additive manufacturing systems for the biomedical market.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The encapsulation of magnetic nickel nanowires (NiNWs) with gelatin is proposed as an alternative for optical label detection. Magnetic nanowires can be detected at very low concentrations using ...light-scattering methods. This detection capacity could be helpful in applications such as transducers for molecular and biomolecular sensors; however, potential applications require the attachment of specific binding molecules to the nanowire structure. In the present study, a method is presented which is helpful in coating magnetic nanowires with gelatin, a material with the potential to handle specific decoration and functionalization of the nanowires; in the first case, silver nanoparticles (AgNPs) are efficiently used to decorate the nanowires. Furthermore, it is shown that the synthesized gelatin-coated particles have excellent detectability to the level of 140 pg/mL; this level of detection outperforms more complex techniques such as ICP-OES (~3 ng/mL for Ni) and magnetoresistance sensing (~10 ng/mL for magnetic nanoparticles).
Pervious concrete has great potential for use in many practical applications as a part of urban facilities that can add value through water harvesting and mitigating severe damage from floods. The ...construction and agricultural industries can take direct advantage of pervious concrete’s characteristics when water is a key factor included in projects as part of the useful life of a facility. Pervious concrete also has applications in vertical constructions, fountains, and pedestrian crossings. This work evidences that pervious concrete’s corrosion current increases with increasing aggregate size. Also, corrosion is a factor to consider only when steel pieces are immersed, aggravated by the presence of chlorine, but it drains water and does not retain moisture. Steel-reinforced pervious concrete was studied, and the grain size of the inert material and the corrosion process parameters were investigated. The electrochemical frequency modulation technique is proposed as a suitable test for a fast, reproducible assessment which, without damaging reinforced cement structures, particularly pervious concrete, indicates a trend of increasing corrosion current density as the size of the aggregate increases or density diminishes.
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