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Frontiers in Chemistry 2024This work successfully demonstrates a sustainable and environmentally friendly approach for synthesizing Semal-ZnO nanoparticles (NPs) using the aqueous leaf extract of...
This work successfully demonstrates a sustainable and environmentally friendly approach for synthesizing Semal-ZnO nanoparticles (NPs) using the aqueous leaf extract of L. These NPs exhibit an absorption peak at approximately 390 nm in the UV-visible spectrum and an energy gap (E) of 3.11 eV. Detailed analyses of the morphology and particle size using various spectroscopic and microscopic techniques, XRD, FE-SEM with EDS, and HR-TEM reveal crystallographic peaks attributable to the hexagonal phase, with an average crystal size of 17 nm. The Semal-ZnO NPs also exhibit a notable photocatalytic efficiency for degrading methylene blue (MB) and methyl orange (MO) under sunlight in different water samples collected from diverse natural sources, indicating that they are promising photocatalysts for environmental remediation. The photocatalytic efficiency of the biofabricated Semal-ZnO NPs is impressive, exhibiting a photodegradation rate of up to 99% for MB and 79% for MO in different water samples under exposure to sunlight. The novel phytofabricated Semal-ZnO NPs are thus a beacon of hope for the environment, with their desirable photocatalytic efficiency, pseudo-first-order kinetics, and ability to break down noxious dye pollutants in various aquatic environments.
PubMed: 38817442
DOI: 10.3389/fchem.2024.1370667 -
Food Chemistry Oct 2024Understanding the evolution of aroma profiles in stored sesame paste (SP) is essential for maintaining its quality. This study investigated the storage quality of SP and...
Understanding the evolution of aroma profiles in stored sesame paste (SP) is essential for maintaining its quality. This study investigated the storage quality of SP and potential aroma markers indicative of sensory degradation. The descriptive sensory analysis demonstrated changes in aroma attributes during storage, transitioning from roasted sesame and nutty aromas to fermented and green aromas. Physicochemical analysis showed deepening color, intensified lipid oxidation, decreased levels of bioactive components, increased particle aggregation, and deteriorated flowability over 63 days at 40 °C. Gas chromatography-olfactometry-mass spectrometry identified 37 aroma-active compounds, with pyrazines, aldehydes, and phenols identified as the major constituents. Partial least squares regression analysis revealed 2-ethyl-3-methyl-pyrazine, 2-methoxy-4-vinylphenol, and benzaldehyde as key aroma-active compounds contributing significantly to the distinctive aromas "roasted nut and roasted sesame" found in SP. Conversely, hexanal and dimethyl disulfide emerged as potential markers of undesirable aromas in SP, including "rancid, green, and fermented". These findings provide insights into SP changes during storage, which is vital for preservation and quality enhancement strategies.
Topics: Sesamum; Odorants; Gas Chromatography-Mass Spectrometry; Food Storage; Taste; Humans; Volatile Organic Compounds; Olfactometry
PubMed: 38815324
DOI: 10.1016/j.foodchem.2024.139809 -
Spectrochimica Acta. Part A, Molecular... Oct 2024In this study, we report the successful synthesis of Ni-doped ZnS nanocomposite via a green route using ethanolic crude extract of Avena fatua. The as-synthesized...
Preparation and Spectrochemical characterization of Ni-doped ZnS nanocomposite for effective removal of emerging contaminants and hydrogen Production: Reaction Kinetics, mechanistic insights.
In this study, we report the successful synthesis of Ni-doped ZnS nanocomposite via a green route using ethanolic crude extract of Avena fatua. The as-synthesized nanocomposite was comprehensively characterized using Dynamic light scattering (DLS), Zeta potential, scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and Atomic force microscopy (AFM). These analyses provided detailed insights into the size, morphology, composition, surface properties, and structural characteristics of the nanocomposite. Subsequently, the synthesized nanocomposite was evaluated for their photocatalytic performance against the organic dye Methyl orange. Remarkably, the nanocomposite exhibited rapid and efficient degradation of Methyl orange, achieving 90 % degradation within only 30 min of irradiation under UV light. Moreover, the photocatalyst demonstrated an exceptional hydrogen production rate, reaching 167.73 µmolgh, which is approximately 4.5 times higher than that of its pristine counterparts. These findings highlight the significant potential of Ni-doped ZnS nanocomposite as highly efficient photocatalysts for wastewater treatment and hydrogen production applications.
PubMed: 38815298
DOI: 10.1016/j.saa.2024.124513 -
Synapse (New York, N.Y.) Jul 2024N-methyl-d-aspartate receptors (NMDARs) at hippocampal excitatory synapses undergo a late postnatal shift in subunit composition, from an initial prevalence of GluN2B...
Individual NMDA receptor GluN2 subunit signaling domains differentially regulate the postnatal maturation of hippocampal excitatory synaptic transmission and plasticity but not dendritic morphology.
N-methyl-d-aspartate receptors (NMDARs) at hippocampal excitatory synapses undergo a late postnatal shift in subunit composition, from an initial prevalence of GluN2B subunit incorporation to a later predominance of GluN2A. This GluN2B to GluN2A shift alters NMDAR calcium conductance dynamics and intracellular molecular signaling that are individually regulated by distinct GluN2 signaling domains and temporally align with developmental alterations in dendritic and synaptic plasticity. However, the impacts of individual GluN2B to GluN2A signaling domains on neuronal development remain unknown. Ionotropic and intracellular signaling domains of GluN2 subunits were separated by creating chimeric GluN2 subunits that were expressed in two transgenic mouse lines. Western blot and immunoprecipitation revealed that roughly one third of native synaptic NMDARs were replaced by transformed NMDARs without altering total synaptic NMDAR content. Schaffer collateral synaptic strength was transiently increased in acutely prepared hippocampal slices at just over 3 weeks of age in animals overexpressing the GluN2B carboxy terminus. Long-term potentiation (LTP) induction following lower frequency stimulation was regulated by GluN2 ionotropic signaling domains in an age-dependent manner and LTP maintenance was enhanced by overexpression of the GluN2B CTD in mature animals. After higher frequency stimulation, the induction and maintenance of LTP were increased in young adult animals overexpressing the GluN2B ionotropic signaling domains but reduced in juveniles just over 3 weeks of age. Confocal imaging of green fluorescent protein (GFP)- labeled CA1 pyramidal neurons revealed no alterations in dendritic morphology or spine density in mice expressing chimeric GluN2 subunits. These results illustrate how individual GluN2 subunit signaling domains do or do not control physiological and morphological development of hippocampal excitatory neurons and better clarify the neurobiological factors that govern hippocampal maturation. SIGNIFICANCE STATEMENT: A developmental reduction in the magnitude of hippocampal long-term synaptic potentiation (LTP) and a concomitant improvement in spatial maze performance coincide with greater incorporation of GluN2A subunits into synaptic NMDARs. Corroborating our prior discovery that overexpression of GluN2A-type ionotropic signaling domains enables context-based navigation in immature mice, GluN2A-type ionotropic signaling domain overexpression reduces LTP induction threshold and magnitude in immature mice. Also, we previously found that GluN2B carboxy terminal domain (CTD) overexpression enhances long-term spatial memory in mature mice and now report that the GluN2B CTD is associated with greater amplitude of LTP after induction in mature mice. Thus, the late postnatal maturation of context encoding likely relies on a shift toward GluN2A-type ionotropic signaling and a reduction in the threshold to induce LTP while memory consolidation and LTP maintenance are regulated by GluN2B subunit CTD signaling.
Topics: Animals; Receptors, N-Methyl-D-Aspartate; Hippocampus; Dendrites; Mice, Transgenic; Mice; Neuronal Plasticity; Long-Term Potentiation; Synaptic Transmission; Excitatory Postsynaptic Potentials; Signal Transduction; Mice, Inbred C57BL; Male
PubMed: 38813758
DOI: 10.1002/syn.22292 -
Dalton Transactions (Cambridge, England... Jun 2024Herein, we present a dark-green crystalline tetranuclear Cu(II) Schiff base complex {C1 = [CuL](ClO)(DMF)(HO)} using a N,N,O donor ligand (HL), namely...
Herein, we present a dark-green crystalline tetranuclear Cu(II) Schiff base complex {C1 = [CuL](ClO)(DMF)(HO)} using a N,N,O donor ligand (HL), namely 2-(((2-hydroxypropyl)imino)methyl)-6-methoxyphenol. Spectro-photometrical investigation on the β-lactamase-like activity of this coordinately saturated system revealed its catalytic inefficiency towards hydrolysis of nitrocefin as a model substrate. This complex has attracted significant interest as a promising photo-catalyst owing to its narrow band gap (2.40 eV) as predicted from DFT calculations and its higher responsivity towards UV light. Therefore, C1 is effectively involved in the photocatalytic reduction of perchlorate to Cl in the presence of a hole scavenger (HO-MeOH) under prolonged UV irradiation and itself becomes photo-cleaved to yield a new dark-brown colored chlorobridged dinuclear crystalline complex C2 {[CuL(HO)Cl]HO}. Furthermore, C2 was deployed as a functional β-lactamase model and was found to show a remarkable catalytic proficiency towards the hydrolysis of nitrocefin in 70 : 30 (V/V) MeOH-HO medium. This pro-catalyst C2 has been speculated to generate an aqua bridged active catalyst that plays a crucial factor in hydrolysis. This phenomenon was again experimentally established by potentiometric pH titration where C2 displays only one pa value (7.11) in the basic pH range, indicating the deprotonation of the bridged water molecule. Based on several other kinetic studies, it may be postulated that the hydrolysis of nitrocefin is initiated by the nucleophilic attack of a bridging hydroxide, followed by very fast protonation of the intermediate to furnish the hydrolyzed product. It is noteworthy that the rate of nitrocefin hydrolysis is greatly inhibited in the presence of external chloride concentration. To the best of our knowledge, this is the first report on the photochemical behavior of such a tetranuclear copper(II) Schiff base complex. Our current interest is focused on inventing a potent β-lactamase inhibitory therapeutic as well as elucidating its mechanism through comprehensive chemical analysis.
Topics: Copper; Coordination Complexes; Density Functional Theory; Ultraviolet Rays; beta-Lactamases; Photochemical Processes; beta-Lactamase Inhibitors; Anti-Bacterial Agents; Hydrolysis; Drug Resistance, Microbial; Molecular Structure
PubMed: 38812408
DOI: 10.1039/d4dt00357h -
Physical Chemistry Chemical Physics :... Jun 2024For the conversion of fructose/methylglucoside (MG) into both methyl formate (MF) and methyl levulinate (MLev), the C-source of formate [HCOO] remains unclear at the...
For the conversion of fructose/methylglucoside (MG) into both methyl formate (MF) and methyl levulinate (MLev), the C-source of formate [HCOO] remains unclear at the molecular level. Herein, reaction mechanisms catalyzed by [CHOH] in a methanol solution were theoretically investigated at the PBE0/6-311++G(d,p) level. For the conversion of fructose into MF and MLev, the formate [HCOO] comes from the C1-atom of fructose, in which the rate-determining step lies in the reaction of 5-hydroxymethylfurfural (HMF) with CHOH to yield MF and MLev. The reaction of fructose with CHOH kinetically tends to generate HMF intermediates rather than yield (MF + MLev). When MG is dissolved in a methanol solution, its O2, O3, and O4 atoms are closer to the first layer of the solvent than O1, O5, and O6 atoms. For the dehydration of MG with methanol into MF and MLev, the formate [HCOO] stems from the dominant C1- and secondary C3-atoms of MG. Kinetically, MG is ready to yield (MF + MLev), whereas fructose can induce the reaction to remain at the HMF intermediate, inhibiting the further conversion of HMF with CHOH into MF and MLev. If MG isomerizes into fructose, the reaction will be more preferable for yielding HMF rather than (MF + MLev).
PubMed: 38808589
DOI: 10.1039/d4cp01455c -
Nature Communications May 2024Luminescent materials with narrowband emission show great potential for diverse applications in optoelectronics. Purely organic phosphors with room-temperature...
Luminescent materials with narrowband emission show great potential for diverse applications in optoelectronics. Purely organic phosphors with room-temperature phosphorescence (RTP) have made significant success in rationally manipulating quantum efficiency, lifetimes, and colour gamut in the past years, but there is limited attention on the purity of the RTP colours. Herein we report a series of closed-loop molecules with narrowband phosphorescence by multiple resonance effect, which significantly improves the colour purity of RTP. Phosphors show narrowband phosphorescence with full width at half maxima (FWHM) of 30 nm after doping into a rigid benzophenone matrix under ambient conditions, of which the RTP efficiency reaches 51.8%. At 77 K, the FWHM of phosphorescence is only 11 nm. Meanwhile, the colour of narrowband RTP can be tuned from sky blue to green with the modification of methyl groups. Additionally, the potential applications in X-ray imaging and display are demonstrated. This work not only outlines a design principle for developing narrowband RTP materials but also makes a major step forward extending the potential applications of narrowband luminescent materials in optoelectronics.
PubMed: 38806515
DOI: 10.1038/s41467-024-48856-3 -
Nature May 2024Asymmetric catalysis allows the synthesis of optically active compounds, often requiring the differentiation between two substituents on prochiral substrates. Despite...
Asymmetric catalysis allows the synthesis of optically active compounds, often requiring the differentiation between two substituents on prochiral substrates. Despite decades of development of mainly noble metal catalysts, achieving differentiation between substituents with similar steric and electronic properties remains a significant challenge. Here, we introduce a class of earth-abundant manganese catalysts for the asymmetric hydrogenation of dialkyl ketimines to give a range of chiral amine products. These catalysts distinguish between pairs of minimally differentiated alkyl groups bound to the ketimine, such as methyl and ethyl, and even subtler distinctions, like ethyl and n-propyl. The degree of enantioselectivity can be adjusted by modifying the components of the chiral manganese catalyst. This reaction demonstrates a wide substrate scope and achieves a turnover number (TON) of up to 107,800. Our mechanistic studies indicate that the exceptional stereoselectivity arises from the modular assembly of confined chiral catalysts and cooperative non-covalent interactions between the catalyst and the substrate.
PubMed: 38806060
DOI: 10.1038/s41586-024-07581-z -
Vestnik Otorinolaringologii 2024Nasal septal perforation (NSP) is a complex problem in otorhinolaryngology, which leads to impaired nasal breathing and dryness in the nose. This reduces the patient's...
UNLABELLED
Nasal septal perforation (NSP) is a complex problem in otorhinolaryngology, which leads to impaired nasal breathing and dryness in the nose. This reduces the patient's quality of life and leads to psychological discomfort. The treatment of nasal septum perforation is selected taking into account the clinical manifestations, perforation parameters and general condition of the patient. Currently, a large number of different surgical methods have been described in order to closing the defect of nasal septum. To date, there is no universally accepted method for closing NSP, which stimulates the search and development of new treatment options.
OBJECTIVE
Under experimental conditions, to study a new method for closing nasal septum perforation using a collagen scaffold together with adipose stromal vascular fraction containing multipotent mesenchymal stromal cells.
MATERIAL AND METHODS
The experiment was carried out on a model of nasal septum perforation in 24 male rabbits divided into four groups, depending on the construct, implanted into the defect zone: the 1st group was the control group - without the introduction of implantation material; the 2nd group - collagen scaffold without adipose stromal vascular fraction; the 3rd group - collagen scaffold with xenogenic adipose stromal vascular fraction; the 4th group - collagen scaffold with allogeneic adipose stromal vascular fraction with further dynamic evaluation of endoscopic control on day 14, after 1 month, 3 months, and 6 months. At month 6, the animals were removed from the experiment, followed by morphological examination in color with hematoxylin and eosin, as well as safranin and methyl green.
RESULTS
As a result of the experiment using adipose stromal vascular fraction of allogeneic and xenogenic origin, closing of perforation of the nasal septum of a rabbit for 3 months of dynamic endoscopic control, as well as according to morphological research, was demonstrated.
CONCLUSION
Our study showed that the use of adipose stromal vascular fraction containing not only endothelial cells and pericytes, but also multipotent mesenchymal stromal cells in combination with a collagen scaffold closes the perforation of the nasal septum in a rabbit, without increasing the risk of violations of habitual vital activity.
Topics: Animals; Rabbits; Nasal Septal Perforation; Disease Models, Animal; Adipose Tissue; Tissue Scaffolds; Male; Mesenchymal Stem Cell Transplantation; Nasal Septum; Treatment Outcome; Collagen
PubMed: 38805459
DOI: 10.17116/otorino20248902121 -
Plants (Basel, Switzerland) May 2024Carotenoids are valuable pigments naturally occurring in all photosynthetic plants and microalgae as well as in selected fungi, bacteria, and archaea. Green microalgae...
Carotenoids are valuable pigments naturally occurring in all photosynthetic plants and microalgae as well as in selected fungi, bacteria, and archaea. Green microalgae developed a complex carotenoid profile suitable for efficient light harvesting and light protection and harbor great capacity for carotenoid production through the substantial power of the endogenous 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway. Previous works established successful genome editing and induced significant changes in the cellular carotenoid content in . This study employs a tailored carotenoid pathway for engineered bioproduction of the valuable ketocarotenoid astaxanthin. Functional knockout of lycopene ε-cyclase (LCYE) and non-homologous end joining (NHEJ)-based integration of donor DNA at the target site inhibit the accumulation of α-carotene and consequently lutein and loroxanthin, abundant carotenoids in without changes in cellular fitness. PCR-based screening indicated that 4 of 96 regenerated candidate lines carried (partial) integrations of donor DNA and increased ß-carotene as well as derived carotenoid contents. Iterative overexpression of BKT, crtB, and CHYB resulted in a 2.3-fold increase in astaxanthin accumulation in mutant ΔLCYE#3 (1.8 mg/L) compared to the parental strain UVM4, which demonstrates the potential of genome editing for the design of a green cell factory for astaxanthin bioproduction.
PubMed: 38794462
DOI: 10.3390/plants13101393