64 research outputs found

    Epigenetic regulation of caloric restriction in aging

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    The molecular mechanisms of aging are the subject of much research and have facilitated potential interventions to delay aging and aging-related degenerative diseases in humans. The aging process is frequently affected by environmental factors, and caloric restriction is by far the most effective and established environmental manipulation for extending lifespan in various animal models. However, the precise mechanisms by which caloric restriction affects lifespan are still not clear. Epigenetic mechanisms have recently been recognized as major contributors to nutrition-related longevity and aging control. Two primary epigenetic codes, DNA methylation and histone modification, are believed to dynamically influence chromatin structure, resulting in expression changes of relevant genes. In this review, we assess the current advances in epigenetic regulation in response to caloric restriction and how this affects cellular senescence, aging and potential extension of a healthy lifespan in humans. Enhanced understanding of the important role of epigenetics in the control of the aging process through caloric restriction may lead to clinical advances in the prevention and therapy of human aging-associated diseases

    Pressure and osmotically driven membrane processes: A review of the benefits and production of nano-enhanced membranes for desalination

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    This review focuses on current research attempts to develop nano-enhanced polymeric desalination membranes. The novel contribution made by this work as compared to many recent reviews on membrane enhancement is that a critical review is made of the effect that the morphological, optical and magnetic properties of the applied nanomaterials have on the efficiency of desalination membranes. The focus on nanomaterials in this review is on both applying new chemical compositions at various concentrations, and also on altering the nanomaterials' morphology and other properties to reach the optimal membrane efficiency for desalination applications. The synthesis route has a major role of tuning the physical and chemical properties of the nanomaterials, and hence, the membrane morphological parameters can be altered, all of which are summarised in this review. The review surveys different types of nanomaterials used for membrane fabrication, such as single elements, metal oxides and nanotubes. Furthermore, mixed oxide composites and polymer/nanomaterial combinations are also considered for membrane enhancement. A wide application range is investigated for modified membranes in pressure and osmotically driven membrane processes for desalination, including reverse osmosis, forward osmosis, osmotically assisted reverse osmosis and pressure assisted forward osmosis

    Thermally induced oxygen related defects in eco-friendly ZnFe2O4 nanoparticles for enhanced wastewater treatment efficiencies

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    Herein, a simple but highly effective strategy of thermal annealing to modulate oxygen vacancies related defects in ZnFe2O4 (ZFO) nanoparticles for obtaining enhanced wastewater treatment efficiencies is reported. The as-prepared nanoparticles were thermally annealed at three different temperatures (500 °C, 600 °C and 700 °C) and their phase purity was confirmed by X-ray diffraction (XRD). All samples were found to exhibit pure phases of ZFO with different crystallite sizes ranging from 10 nm to 25 nm. The transmission electron microscope (TEM) images showed well dispersed nanoparticles and a strong correlation of grain size growth with annealing temperature was established. The optical absorption and emission characteristics were estimated through UV–visible and Photoluminescence (PL) spectroscopy. Raman spectroscopy and X-ray Photoelectron Spectroscopy (XPS) confirmed the variation of oxygen vacancies in the synthesized samples’ lattice. The photocatalytic activities of all samples were investigated and the highest efficiencies were recorded for the ZFO samples annealed at 500 °C. Under high salinity condition, the organic dye degradation efficiency of the same sample remained the highest among all. The excellent dye degradation abilities in ZFO samples can be attributed to the abundance of oxygen vacancies in the crystal lattice that slow down the recombination rate during the photocatalysis process. Moreover, cytotoxicity tests revealed that all prepared ZFO samples showed insignificant cell structure effects on Picochlorum sp microalgae, as verified by Fourier-transform infrared (FTIR) spectroscopy. On the other hand, no significant changes were detected on the viable cell concentration and Chlorophyll a content. This work presents a systematic way to finely tune the crystal sizes and to modulate oxygen related defects in ZFO through a highly effective annealing approach to signify their potential in industrial wastewater and seawater treatment processes

    Antimicrobial activity of three essential oils (cinnamon, manuka, and winter savory), and their synergic interaction, against Listeria monocytogenes

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    Essential oils (EOs) are categorized as having antimicrobial, insecticidal, and antioxidant activities. For their antibacterial activity, EOs are widely studied as alternatives to antibiotics in human and veterinary medicines. The inhibitory and bactericidal activities of three EOs (Cinnamomum zeylanicum, Leptospermum scoparium, and Satureja montana) were determined against Listeria monocytogenes ATCC 7644. The chemical compositions of the EOs were determined through gas chromatography mass spectrometry (GC-MS). Essential oils were tested alone or in binary and ternary combinations for both their inhibitory and their bactericidal activities. Binary and ternary mixtures were tested through a chequerboard assay, and thus fractional inhibitory and fractional bactericidal concentration indices were obtained in relation to the activity of each EO alone. The chemical composition of each EO had different percentages of the main classes of compounds. EOs showed high levels of monoterpenes (hydrocarbons and oxygenated), sesquiterpenes (hydrocarbons and oxygenated), and phenylpropanoids for winter savory, manuka, and cinnamon, respectively. Several synergistic activities against Listeria monocytogenes were demonstrated in binary and ternary mixtures of the EOs. Mixtures of the EOs tested showed potential for use as antibacterial products; moreover, because of the synergistic activities the mixtures could be used in lower quantities than individual EOs on their own

    Optical properties and first-principles study of CH₃NH₃PbBr₃ perovskite structures

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    Abstract Solution-processed organic–inorganic hybrid perovskites have attracted attention as light-harvesting materials for solar cells and photonic applications. The present study focuses on cubic single crystals and microstructures of CH₃NH₃PbBr₃ perovskite fabricated by a one-step solution-based self-assembly method. It is seen that, in addition to the nucleation from the precursor solution, crystallization occurs when the solution is supersaturated, followed by the formation of a small nucleus of CH₃NH₃PbBr₃ that self-assembles into bigger hollow cubes. A three-dimensional (3D) fluorescence microscopy investigation of hollow cubes confirmed the formation of hollow plates on the bottom; then, the growth starts from the perimeter and propagates to the center of the cube. Furthermore, the growth in the (001) direction follows a layer-by-layer growth model to form a complete cube, confirmed by scanning electronic microscopy (SEM) observations. Two-dimensional (2D)–3D fluorescence microscopy and photoluminescence (PL) measurements confirm a peak emission at 535 nm. To get more insights into the structural and optical properties, density functional theory (DFT) simulations were conducted. The electronic and optical properties calculated by DFT are in agreement with the obtained experimental values. The density-of-state (DOS) calculations revealed that the valence band maximum (VBM) consists of states contributed by Br and Pb, which agrees with the X-ray photoelectron spectroscopy valence band (XPS VB) measurements
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