The novel coronavirus, SARS-CoV-2, broken out as the COVID-19 epidemic, is transported into the cytoplasm by angiotensin-converting enzyme-2 (ACE2), a key protein of the renin-angiotensin-system ...(RAS). ACE2 is a protective protein that reduces angiotensin (Ang) II, the bioactive component of RAS, by converting it to its potent antagonist, Ang-(1-7) peptide, in order to provide a pathophysiological response to stimuli. Although ACE-2 is upregulated especially in pulmonary endothelial cells and alveolar epithelial cells, downregulation of ACE-2 in the lung owing to loss of key regulatory factors explains the enzyme-dependent lethality of SARS-CoV-2. The N-terminal domain (NTD) of S1, one of the protein subunits of coronaviruses, is known to recognize acetylated sialic acids on glycosylated cell surface receptors. In this study, the stearic acid-peptide conjugate mimicking the sialic acid structure was synthesized, which will be able to balance uncontrolled inflammatory response and excessive cytokine production, and depending on these to suppress pneumonia and acute respiratory distress syndrome (ARDS), against SARS-CoV-2. It was expected that fatty acid acylation would greatly enhance cellular internalization and cytosolic distribution of the peptide through the cell membrane. Thus, we synthesized fatty acyl derivative of the N-Ac-Gly4-Ang (1-7) peptide. The peptide was synthesized using Fmoc/tBu solid-phase peptide chemistry and characterized by FT-IR, Zetasizer, and LC-ESI-MS. This study provided more detailed insights into understanding and meeting the basic structural requirements for optimal cellular delivery and formulation of the stearyl Ang (1-7)-peptide conjugate.
Superhydrophobic surface materials on metallic substrate have attracted widespread research interest due to tremendous promising application value in various fields. Superhydrophobic surface on Ti ...substrate was successfully obtained with a two-step method. Firstly, micro/nano-cone or flower-like structures were fabricated in the mixture solution of H3PO4/NH4F by a simple, cost-effective anodization method, and then modified with stearic acid. The synergistic effect both of them achieved a superhydrophobic surface. Effects of anodization parameters including NH4F concentration in the mixture of H3PO4/NH4F electrolyte, anodization time and anodization voltage on the morphology and wettability of the superhydrophobic surfaces were systematically studied and optimized. It is found that the surface was getting rougher and rougher with the increase of NH4F concentration in the mixture, anodization time and anodization voltage, respectively, meanwhile, the corresponding contact angles (CAs) were gradually increase and corresponding sliding angles (SAs) were gradually decrease, respectively. Results showed that the best superhydrophobicity surface with a maximum CA of ~170.3° and a SA of approximately 0° were obtained at room temperature when the anodizing voltage, anodizing time and the mixture electrolyte concentration were 100 V, 60 min and 5 wt% H3PO4/0.5 wt%NH4F, respectively. Formation mechanisms of the micro/nano-protrusion hierarchical structures were also discussed. Additionally, the superhydrophobic surface exhibited ultralow adhesion, a long-term stability, excellent self-cleaning effect and good anti-icing property.
With the increasing global population, fossil fuel resources still represent a main contributor to the energy supply, despite the progress made in the field of renewable energies. Large quantities of ...residual oil from mature reservoirs cannot be produced through primary and secondary recovery methods. Among alternative recovery techniques, chemically enhanced oil recovery methods are attracting considerable interest to increase the hydrocarbon recovery from oil-bearing geological formations. The wettability of any particular formation can be used to predict the oil recovery factor of a reservoir based on its wetting state. However, due to the complex nature of geological porous media, special treatments are required to control the wetting characteristics for improving the oil recovery. In this work, methyl orange (MO), a hazardous pollutant widely discharged in industrial wastewater, was used as a chemical agent for the purpose of altering the wettability. Initially, quartz substrates were aged with 10−2 mol/L n-decane/stearic acid solution to mimic natural geological conditions; then, stearic acid-aged quartz substrates were treated in various concentrations of MO (10, 25, 50, 75, and 100 mg/L) for 7 days at 50 °C, followed by advancing and receding contact angle measurements at various physico-thermal geological conditions (temperature 25, 50 °C, pressure 10, 15, 20 MPa, and brine salinity 0–0.3 M). Our results demonstrate that increasing the temperature, pressure, and salinity of quartz aged with stearic acid has a negative effect on the wettability (resulting in a higher hydrophobicity). However, at any constant physio-thermal condition, MO significantly alters the wettability of the organic-aged quartz substrates from oil-wet to water-wet conditions, thus improving oil recovery. The concentration of MO plays a critical role, with increasing concentrations favouring the water-wet conditions. Quartz aged with MO at a concentration of 100 mg/L shows water-wet behaviour, with the lowest advancing and receding contact angles of 31° and 29°, respectively, at 25 °C, 20 MPa, and 0.3 M salinity. The findings of this study provide new insights that can be useful for disposing MO in deep underground reservoirs rather than discharging into the hydrosphere, thus mitigating climate change. In addition, the present data can be helpful for improving the oil productivity from sandstone reservoirs.
•Superhydrophobic CuS cotton fabric was prepared for multifunctional applications.•The fabric achieved oil/water separation with high efficiency and good reusability.•The fabric held excellent ...photocatalytic performance and antibacterial activity.
A simple and low-cost fabrication of superhydrophobic cotton fabric has been reported by coating CuS on the fabric surface and subsequent stearic acid modification for multifunctional applications. The fabricated fabric showing superhydrophobicity and superoleophilicity was used for oil/water separation with high separation efficiency over 98% and desirable recyclability. Moreover, the fabric was active in degrading methylene blue aqueous solution under visible light irradiation. Importantly, the fabric was proved to possess excellent antibacterial activities against Pseudomonas aeruginosa and Staphylococcus aureus. These attractive performances presented in this work make the fabric a very promising candidate for actual wastewater treatment on a large scale.
A new class of ricinoleic acid-derived branched surfactant with a Y-shaped structure (ethoxylated monohydroxy stearic acid methyl ester, 12-HMEE
n
) was synthesized and characterized by introducing a ...polyoxyethylene head group in the hydroxyl position inside the molecule. The physicochemical properties and surface activities of 12-HMEE
n
with different degrees of ethoxylation at various concentrations were studied. The typical Y-shaped structure of the molecule facilitates its adsorption at the interface, which provides an excellent surface activity and affects its surfactant properties significantly. The dynamic contact angle, wettability, foaming properties, and compatibility tests of 12-HMEE
n
showed that it has good wetting performance, low foaming and fast defoaming properties, and good compatibility in formulation applications, indicating that the surfactant has potential application in industrial cleaning.
A branched nonionic biosurfactant (12-HMEE
n
) from non-edible oils with a single hydrophilic head group has excellent surface properties which make it suitable for application in hard surface cleaning.
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•Different LED wavelengths were used for the cultivation of marine microalgae.•LED wavelengths used were blue (457nm), red (660nm) and red mix blue.•The results were also compared to ...white fluorescent lamp.•Microalgae showed highest growth rate and lipid production under blue LED wavelength.•Analysis showed major FAME components were palmitic acid and stearic acid.
Wavelength of light is a crucial factor which renders microalgae as the potential biodiesel. In this study, Tetraselmis sp. and Nannochloropsis sp. as famous targets were selected. The effect of different light wavelengths on growth rate and lipid production was studied. Microalgae were cultivated for 14days as under blue, red, red-blue LED and white fluorescent light. The growth rate of microalgae was analyzed by spectrophotometer and cell counting while oil production under improved Nile red method. Optical density result showed the microalgae exhibited better growth curve under blue wavelength. Besides, Tetraselmis sp. and Nannochloropsis sp. under blue wavelength showed the higher growth rate (1.47 and 1.64day−1) and oil production (102.954 and 702.366a.u.). Gas chromatography analysis also showed that palmitic acid and stearic acid which were compulsory components for biodiesel contribute around 49–51% of total FAME from Nannochloropsis sp. and 81–83% of total FAME from Tetraselmis sp.
Abstract Objective The role of saturated fatty acids (SFAs) in chronic disease remains controversial; inflammation is one pathway by which SFAs influence the risk for chronic disease. The aim of this ...study was to investigate the associations between red blood cell (RBC) phospholipid SFAs and systemic inflammation. Methods As part of a randomized controlled trial, we measured RBC phospholipid FA composition in 55 generally healthy adults twice at 3-mo intervals. We estimated associations of RBC total SFAs and two major SFA subtypes, palmitic and stearic acids, with C-reactive protein (CRP), interleukin (IL)-6, white blood count (WBC), and a composite inflammation measure using generalized estimating equations in multivariable FA substitution models. Results Mean (±SD) SFA level across both visits was 45% ± 3% of the total RBC FAs, mainly palmitic (21% ± 1%) and stearic (17% ± 3%) acids. In models adjusted for age, sex, race, smoking, body mass index, statin use, aspirin use, transunsaturated FAs, and ω-3 FAs, SFAs were significantly associated with IL-6 (20% increase per 1 SD increment; 95% confidence interval CI, 0.03%–43%; P = 0.05) and the composite inflammation measure ( P = 0.05) and marginally associated with CRP (34% increase; 95% CI, −1% to 81%; P = 0.06), but not associated with WBC. Stearic acid was positively associated with CRP (35% increase; 95% CI, 2%–79%; P = 0.04). Palmitic acid was marginally associated with the composite inflammation measure ( P = 0.06) and, upon additional ω-6 FA adjustment, significantly associated with IL-6 (15% increase; 95% CI, 0.4%–27%; P = 0.006). Conclusions RBC SFAs, which represent longer-term dietary intake, are positively associated with inflammation. In particular, palmitic acid was associated with IL-6, and stearic acid was associated with CRP after multivariable adjustment.
Non-native structures (NNS) differ in discrete translational symmetry from the bulk ground state native structure (NS). To explore the extent of deconvolution of various factors relevant to the ...stabilization of the wurtzite/NNS of MnSe via a heat-up method, we performed experiments using various ligands (oleic acid, oleylamine, octadecylamine, stearic acid, and octadecene), solvents (tetraethylene glycol and octadecene), and precursor salts (manganese chloride and manganese acetate). Experiments suggest that oleic acid in the presence of tetraethylene glycol and oleylamine in the presence of octadecene stabilize wurtzite/NNS. Further, density functional theory (DFT) computations explore the interaction between the functional groups in ligands and the most exposed surfaces of wurtzite/NNS and rocksalt/NS polymorphs. Computations suggest that the interactions between relevant surface facets with carboxylic acid and the double bond functional groups suppress the phase transformation from NNS to NS. In addition, the ionizability of the precursor salt also determines the rate of formation of the metal–ligand complex and the rate of nucleation. Consequently, the formation rate of the Mn–ligand complex is expected to be greater in the case of chloride salt than acetate salt because the chloride salt has higher ionizability in ethylene glycol. From the above, we conclude that the kinetics of the wurtzite/NNS to rocksalt/NS phase transformation depends mainly on two factors: (1) nucleation/growth kinetics which is controlled by the ionizability of the precursor salt, solvent, and stability of the metal–ligand complex, and (2) the activation energy barrier of the NNS to NS conversion which is controlled by surface energy minimization with the ligand.
For enhancing the heat storage and encapsulation performances of organic phase change materials (PCMs), a carbon foam (CF) with a continuous dual-scale pore structure (DCF) was developed. Employing ...the as-prepared DCF as a stearic acid (SA) support, a novel shape-stabilized SA–CF composite PCM with a continuous dual-scale interpenetrating network structure was achieved through the impregnation of SA into the DCF. DCF-900, prepared at an activation temperature of 900 °C, possesses a high loading capacity of 89.54 wt % for melted SA without leakage. The resulting SA/DCF-900 composite with a continuous dual-scale interpenetrating network structure exhibits excellent comprehensive performances with a good synergistic effect. The composite presents a thermal conductivity of 1.298 W/m·K and an encouraging compressive strength of 9.03 MPa, which increase by 2.25-fold and 3.56-fold compared with those of DCF-900, respectively. Furthermore, its melting and freezing enthalpies reach 192.8 and 192.7 J/g with a storage efficiency of about 100%, respectively; meanwhile, it displays excellent thermal cycle stability and reversibility after 600 thermal cycles with a high melting/freezing enthalpy retention rate of up to 96%. More importantly, its light-to-thermal conversion efficiency reaches 91.8% under a light intensity of 100 mW/cm2. Consequently, the SA/DCF-900 composite is a promising candidate for high-performance PCMs.
The ff transition of lanthanide ions such as Eu in the complex appears as unique energy relaxation process as luminescence after the intramolecular energy transfer from the photo-excitation of the ...ligand with π-electronic system. The Langmuir-Blodgett (LB) film consisting of Eu and amphiphilic naphtoic acids (NaphC
) induced the linearly polarized luminescence (LPL) with a medium, stearic acid (SA), to isolate the luminescence component by the layer structure and to keep the softness at the monolayer depositions on the quartz substrate as reported previously. Here, we used a bulky medium, 3-methyl-4-penthadecyl benzoic acid (MPBA), instead of SA, and found the Eu-NaphC
in the LB film places more independently resulting in the 4-fold high quantum yields compared with previous system. The structures of LB films of Eu-NaphC
with MPBA were elucidated by the measurement of synchrotron XRD and XPS. Various electronic spectra were quantitatively observed to discuss the effect molecular aggregation through much/less ππ-interaction of NaphC
for the intensified LPL in the films.
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