41 research outputs found

    Formulation and Stabilization of Concentrated Edible Oil-in-Water Emulsions Based on Electrostatic Complexes of a Food-Grade Cationic Surfactant (Ethyl Lauroyl Arginate) and Cellulose Nanocrystals

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    We report on high-internal-phase, oil-in-water Pickering emulsions that are stable against coalescence during storage. Viscous, edible oil (sunflower) was emulsified by combining naturally derived cellulose nanocrystals (CNCs) and a food-grade, biobased cationic surfactant obtained from lauric acid and L-arginine (ethyl lauroyl arginate, LAE). The interactions between CNC and LAE were elucidated by isothermal titration calorimetry (ITC) and supplementary techniques. LAE adsorption on CNC surfaces and its effect on nanoparticle electrostatic stabilization, aggregation state, and emulsifying ability was studied and related to the properties of resultant oil-in-water emulsions. Pickering systems with tunable droplet diameter and stability against oil coalescence during long-term storage were controllably achieved depending on LAE loading. The underlying stabilization mechanism was found to depend on the type of complex formed, the LAE structures adsorbed on the cellulose nanoparticles (as unimer or as adsorbed admicelles), the presence of free LAE in the aqueous phase, and the equivalent alkane number of the oil phase (sunflower and dodecane oils were compared). The results extend the potential of CNC in the formulation of high-quality and edible Pickering emulsions. The functional properties imparted by LAE, a highly effective molecule against food pathogens and spoilage organisms, open new opportunities in food, cosmetics, and pharmaceutical applications, where the presence of CNC plays a critical role in achieving synergistic effects with LAE

    Electrospun Poly(lactic acid)-Based Fibrous Nanocomposite Reinforced by Cellulose Nanocrystals: Impact of Fiber Uniaxial Alignment on Microstructure and Mechanical Properties

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    Uniform poly­(lactic acid)/cellulose nanocrystal (PLA/CNC) fibrous mats composed of either random or aligned fibers reinforced with up to 20 wt % CNCs were successfully produced by two different electrospinning processes. Various concentrations of CNCs could be stably dispersed in PLA solution prior to fiber manufacture. The microstructure of produced fibrous mats, regardless of random or aligned orientation, was transformed from smooth to nanoporous surface by changing CNC loading levels. Aligning process through secondary stretching during high-speed collection can also affect the porous structure of fibers. With the same CNC loading, fibrous mats produced with aligned fibers had higher degree of crystallinity than that of fibers with random structure. The thermal properties and mechanical performances of PLA/CNC fibrous mats can be enhanced, showing better enhancement effect of aligned fibrous structure. This results from a synergistic effect of the increased crystallinity of fibers, the efficient stress transfer from PLA to CNCs, and the ordered arrangement of electrospun fibers in the mats. This research paves a way for developing an electrospinning system that can manufacture high-performance CNC-enhanced PLA fibrous nanocomposites

    Sustainable Production of Stable Lignin Nanoparticle-Stabilized Pickering Emulsions via Cellulose Nanofibril-Induced Depletion Effect

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    Spherical lignin nanoparticles (SLNs) are able to formulate Pickering emulsions with various applications. However, SLN-stabilized emulsions commonly comprise droplets in the micron range, resulting in inevitable instability upon storage. Herein, nonadsorbing cellulose nanofibrils (CNF) are shown to induce stabilization of the diluted SLN-stabilized Pickering emulsions via concentration-dependent depletion effects. Two regimes for such depletion interactions are established, including depletion flocculation-induced droplet aggregation at intermediate CNF concentrations and depletion stabilization of micron-sized droplets over critical CNF concentrations (0.2 wt %). The long-term stability of the SLN-based emulsions against creaming is over two months. The universality of the findings is tested with different initial oil volume fractions and droplet diameters. Overall, this study unveils the depletion effects in SLN-stabilized Pickering emulsions induced by renewable CNF, offering a simple, sustainable route for tailoring their phase behavior and creating ultrastable systems that are available for formulating green products

    Depletion Effects and Stabilization of Pickering Emulsions Prepared from a Dual Nanocellulose System

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    Nonadsorbing cellulose nanofibrils (CNF) are shown to induce stabilization of dilute oil-in-water Pickering emulsions formed by interfacial adsorption of highly charged TEMPO-oxidized CNF (TOCNF). The correlative interactions that occur upon sequential addition of the two types of nanofibrils (TOCNF and CNF) afford control of the properties of the obtained emulsions. For instance, the emulsions undergo (1) creaming of nonflocculated droplets at low CNF concentrations, (2) destabilization by depletion flocculation at intermediate concentrations of the nonadsorbing CNF, and (3) stabilization by formation of a fibrillar network and gelation above a critical CNF concentration (∼0.15 wt %). The observed phenomena are reproduced in TOCNF-stabilized emulsions of varying droplet sizes (3.6, 6.9, and 11 μm). The interactions induced by the presence of CNF in TOCNF-based Pickering emulsions allow tailoring emulsion stability, most useful in fully green, all-cellulose foodstuff, cosmetic, and pharmaceutical formulations

    Enhanced Cell Osteogenesis and Osteoimmunology Regulated by Piezoelectric Biomaterials with Controllable Surface Potential and Charges

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    Bone regeneration is a well-orchestrated process involving electrical, biochemical, and mechanical multiple physiological cues. Electrical signals play a vital role in the process of bone repair. The endogenous potential will spontaneously form on defect sites, guide the cell behaviors, and mediate bone healing when the bone fracture occurs. However, the mechanism on how the surface charges of implant potentially guides osteogenesis and osteoimmunology has not been clearly revealed yet. In this study, piezoelectric BaTiO3/β-TCP (BTCP) ceramics are prepared by two-step sintering, and different surface charges are established by polarization. In addition, the cell osteogenesis and osteoimmunology of BMSCs and RAW264.7 on different surface charges were explored. The results showed that the piezoelectric constant d33 of BTCP was controllable by adjusting the sintering temperature and rate. The polarized BTCP with a negative surface charge (BTCP−) promoted protein adsorption and BMSC extracellular Ca2+ influx. The attachment, spreading, migration, and osteogenic differentiation of BMSCs were enhanced on BTCP–. Additionally, the polarized BTCP ceramics with a positive surface charge (BTCP+) significantly inhibited M1 polarization of macrophages, affecting the expression of the M1 marker in macrophages and changing secretion of proinflammatory cytokines. It in turn enhanced osteogenic differentiation of BMSCs, suggesting that positive surface charges could modulate the bone immunoregulatory properties and shift the immune microenvironment to one that favored osteogenesis. The result provides an alternative method of synergistically modulating cellular immunity and the osteogenesis function and enhancing the bone regeneration by fabricating piezoelectric biomaterials with electrical signals

    Table_1_The Exploration of Poor Ovarian Response–Related Risk Factors: A Potential Role of Growth Differentiation Factor 8 in Predicting Ovarian Response in IVF-ET Patient.docx

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    Controlled ovarian hyperstimulation (COH) is the most common therapeutic protocol to obtain a considerable number of oocytes in IVF-ET cycles. To date, the risk factors affecting COH outcomes remain elusive. Growth differentiation factor 8 (GDF-8), a member of transforming growth factor β (TGF-β) superfamily, has been long discerned as a crucial growth factor in folliculogenesis, and the aberrant expression of GDF-8 is closely correlated with the reproductive diseases. However, less is known about the level of GDF-8 in IVF-ET patients with different ovarian response. In the present study, the potential risk factors correlated with ovarian response were explored using logistic regression analysis methods. Meanwhile, the expression changes of GDF-8 and its responsible cellular receptors in various ovarian response patients were determined. Our results showed that several factors were intensely related to poor ovarian response (POR), including aging, obesity, endometriosis, surgery history, and IVF treatment, while irregular menstrual cycles and PCOS contribute to hyperovarian response (HOR). Furthermore, POR patients exhibited a decrease in numbers of MII oocytes and available embryos, thereby manifesting a lower clinical pregnancy rate. The levels of GDF-8, ALK5, and ACVR2B in POR patients were higher compared with those in control groups, whereas the expression level of ACVR2A decreased in poor ovarian response patients. In addition, clinical correlation analysis results showed that the concentration of GDF-8 was negatively correlated with LH and estradiol concentration and antral follicle count. Collectively, our observations provide a novel insight of ovarian response–associated risk factors, highlighting the potential role of GDF-8 levels in ovarian response during COH process.</p

    DataSheet1_Nitrogen Fertilization of Lawns Enhanced Soil Nitrous Oxide Emissions by Increasing Autotrophic Nitrification.DOCX

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    As nitrous oxide (N2O) is one of the most important greenhouse gases, N2O emission pathways and regulation techniques in soils with different vegetation types have become a research focus. Currently, a diverse array of research exists on the N2O emissions from soils of different vegetation types, e.g., forest, grassland, and agriculture. Few studies have investigated the microbial processes of N2O emissions from lawn soils. Fertilization levels in lawn soils are often similar to or much higher than those in agricultural ecosystems, thus fertilized lawn is an important source of atmospheric N2O. In the study, we employed the 15N-nitrate labelling method combined with the nitrification inhibition technique to distinguish microbial processes and their contribution to N2O emissions in long-term nitrogen fertilised lawns. We found that the N2O emission rate from the control treatment was 1.0 nmol g−1 h−1 over the incubation, with autotrophic nitrification contributing 60%. The N2O emission rate increased to 1.4 nmol g−1 h−1 from the soil treated with long-term N fertilization, and the contribution of autotrophic nitrification increased to 69%. N fertilization did not significantly increase the contribution of denitrification (24–26%) in the total N2O emissions. However, N fertilization substantially decreased the contribution of heterotrophic nitrification from 13 to 0.4% in the total N2O emissions. Co-denitrification to N2O was detected but the overall contribution was of minor importance (3–5%). The correlation analysis revealed that soil NO3− levels were the main influencing factors in the N2O producing microbial processes. Our results suggest that N fertilization altered both N2O production rates and the contribution pattern of microbial processes, and indicate the autotrophic nitrification and heterotrophic nitrification are more sensitive to N fertilization than denitrification and co-denitrification.</p
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