Influence Of Na Research Articles

Antioxidant Activity, In Vitro Digestibility and Stability of Flaxseed Oil and Quercetin Co‐Loaded Submicron Emulsions

Flaxseed oil and quercetin have received extensive attention in food industry. However, their poor solubility in water and stability are major limitations for their application in functional foods. In this work, we encapsulated flaxseed oil and quercetin into submicron emulsions by high pressure homogenization method to overcome their shortcomings in application. The loading of flaxseed oil in submicron emulsions was 10% and the solubility of quercetin in water is increased by at least 1300 folds. In vitro antioxidant study indicated that the addition of flaxseed oil could increase the antioxidant activity of quercetin. During in vitro digestion, the smaller the particle size of submicron emulsions, the faster the digestive rate of flaxseed oil and the higher the bio‐accessibility of quercetin. Furthermore, accelerated oxidation study revealed that quercetin could protect flaxseed oil effectively. Besides, metallic ions stability study illustrated that the influence of Na+ on the emulsion stability is smaller than that of Ca2+ and high Ca2+ concentration could lead to stratification of the submicron emulsions. The storage stability shows that the prepared submicron emulsions can be stored for 8 weeks at three different temperatures. Hence, submicron emulsion can be a promising vehicle for delivery of flaxseed oil and quercetin.Practical Applications: Submicron emulsions can be used to improve the water solubility and bioavailability of lipophilic nutrients. The combination of flaxseed oil and quercetin in submicron emulsions can compensate for their individual shortcomings in application and exert synergistic beneficial actions on human health. Furthermore, this technology is easy in operation and can be realized in industry. Flaxseed oil and quercetin co‐loaded submicron emulsions can be applied in milk and liquid beverages in food industry.Submicron emulsions are fabricated to enhance the delivery of flaxseed oil and quercetin. The smaller the particle size of submicron emulsions, the faster the digestive rate of flaxseed oil and the higher the bio‐accessibility of quercetin. Quercetin can protect flaxseed oil against oxidation effectively. The antioxidant effect of quercetin is found to be better than commonly used antioxidants.

Influence of Na and Nb co-substitution on electrochemical performance of ternary cathode materials for Li-ion batteries

In the present study, Li1−xNax(Ni0.6Co0.2Mn0.2−yNby)O2, a novel layered cathodic compound, is synthesized using an economically feasible polymer pyrolysis method.

Natural and artificial aging in Mg-Gd binary alloys

Early precipitation stages are now frequently observed in Mg alloys with rare earth due to a development of new microscopy techniques. Information about a very early precipitation at room temperature (i.e. natural aging, NA), however, is rare even in Mg alloys with a very well described precipitation sequence. Moreover, there are only few works dealing with an influence of NA on subsequent thermal processes in Mg alloys. The aim of this work was to study kinetics of the NA performed up to 5 years in an Mg-RE system and its influence on a subsequent artificial aging. The solution treated Mg-Gd was chosen as a model binary system where the NA as well as precipitation development during isochronal and isothermal heat treatment was observed. Electrical resistivity measurements at low and well-defined temperature (77 K) and Vickers microhardness were used for monitoring of a solute clustering during the NA. The kinetics of this process is much slower than observed in aluminum alloys and both methods give identical values of kinetics parameters in simple models. The validity of concentration dependences of microhardness and yield stress values supports these models. The NA intensifies precipitation strengthening in solution treated Mg-Gd alloy with 15 wt % Gd isochronally annealed up to 200 °C. Formation of short range ordered super hexagons consisting of 6 columns of Gd atoms along the [0001] direction resembling the D019 structure was revealed by electron diffraction in specimen isochronally annealed up to 200 °C. The maximum hardening during isochronal annealing up to 300 °C shifts to higher annealing temperatures in the naturally aged specimen. Precipitates of the orthorhombic β′ phase (aβ’ = 2aMg, bβ’ = 4√3aMg, cβ’ = cMg) were identified after isothermal artificial aging for 165 h at 200 °C in the Mg-Gd with 15 wt% in a cell-like arrangement despite of the NA. Since the mesh size is much smaller in the naturally aged alloy, however, it causes the better hardening effect.

Reconsideration on Hydration of Sodium Ion: From Micro-Hydration to Bulk Hydration

Micro hydration structures of the sodium ion, [Na(H2O) n ]+, n = 1–12, were probed by density functional theory (DFT) at B3LYP/aug-cc-pVDZ level in both gaseous and aqueous phase. The predicted equilibrium sodium–oxygen distance of 0.240 nm at the present level of theory. The four-, five- and six-coordinated cluster can transform from each other at the ambient condition. The analysis of the successive water binding energy and natural charge population (NBO) on Na+ clearly shows that the influence of Na+ on the surrounding water molecules goes beyond the first hydration shell with the hydration number of 6. The Car-Parrinello molecular dynamic simulation shows that only the first hydration sphere can be found, and the hydration number of Na+ is 5.2 and the hydration distance (rNa–O) is 0.235 nm. All our simulations mentioned in the present paper show an excellent agreement with the diffraction result from X-ray scattering study.

Influence of Na in Cu2SnS3 film on its physical properties and photovoltaic performances

Cu2SnS3 (CTS) is the promising absorber of thin-film solar cell due to earth-abandant and non-toxic element. Influence of sodium (Na) on physical properties of CTS layers is investigated. In this work, CTS films with different Na concentrations are fabricated by sulfurizations of NaF/Cu/SnS2 and Cu/SnS2 stacked precursors on both soda-lime glass (SLG) and quartz substrates. The Na from NaF precursor layer and SLG substrate is introduced into CTS films. It is demonstrated that Na in forms of NaxCuSnS3 (x: 0.5–1.0) and Na2S is segregated in the large grain regions of CTS films. The crystal grains are significantly enlarged by Na addition into CTS films. As a result, the carrier lifetime, examined by time-resolved photoluminescence, is enhanced. From Raman scattering measurement, CTS films possess the peaks of monoclinic CTS structure. In addition, Cu2Sn3S7 and NaxCuSnS3 peaks are clearly observed in CTS films with high Na content. Finally, conversion efficiency of CTS thin-film solar cell is strongly enhanced from 0.61 (without Na addition) to 2.01% (with Na addition), mainly attributed to the increases in open-circuit voltage and fill factor through the decrease in carrier recombination.

Adsorbate doping of MoS2 and WSe2: the influence of Na and Co

We have investigated the influence of metal adsorbates (sodium and cobalt) on the occupied and unoccupied electronic structure of MoS2(0 0 0 1) and WSe2(0 0 0 1), through a combination of both photoemission and inverse photoemission. The electronic structure is rigidly shifted in both the WSe2 and MoS2 systems, with either Na or Co adsorption, generally as predicted by accompanying density functional theory based calculations. Na adsorption is found to behave as an electron donor (n-type) in MoS2, while Co adsorption acts as an electron acceptor (p-type) in WSe2. The n-type transition metal dichalcogenide (MoS2) is easily doped more n-type with Na deposition while the p-type transition metal dichalcogenide (WSe2) is easily doped more p-type with Co deposition. The binding energy shifts have some correlation with the work function differences between the metallic adlayer and the transition metal dichalcogenide substrate.

Influence of Na on grain boundary and properties of Cu(In,Ga)Se2 solar cells

AbstractWhether added from external sources or supplied via substrate, incorporation of Na has always improved the conversion efficiency of polycrystalline thin‐film Cu(In,Ga)Se2 (CIGS) solar cells. Segregation of Na along grain boundary (GB) is thought to be one of the main reasons for better efficiency, and changing its concentration levels may tune the device properties accordingly. Our previous works have shown that changes in GB chemistry over various Ga/In concentrations are the main reason for poor performance of Ga‐rich (18%) CIGS, besides its optimum band gap (1.4 eV) for energy conversion. It was suspected that changes in GB chemistry or device performance or both could be driven by variation in Na concentration at GB. In this research, atomic level fluctuations of Na atoms at GB for various CuIn1−xGaxSe2 thin films were measured accurately with atom probe tomography technique. Fluctuations observed in Na concentration at GB are restricted to the range 0.5–6.5 atoms per nm2 and is irrespective of x value (GGI) and GB surface density. Results also show that changes in GB chemistry for similar CIGS compositions are not necessary due to changes in Na concentration levels at GB. However, an increased density of GBs per unit volume with GGI may indicate an overall rise in Na in thin films and could explain the drop in CIGS performance. Copyright © 2017 John Wiley & Sons, Ltd.

Modulation of the work function of graphene by Na and Cl coadsorbed on opposite sides on graphene

The influence of Na and Cl atoms coadsorption on the work functions (WFs) of graphene was investigated by first-principles calculations under density functional theory. Although there is very little net charge on the surface of graphene due to charge redistribution among the adsorbates and substrate, the WFs of graphene still change dramatically.

Influence of Na+, K+, Mn2+, Fe2+ and Zn2+ ions on the electrodeposition of Ni-Co alloys: Implications for the recycling of Ni-MH batteries

A hydrometallurgical recycling procedure for the recovery of a mixed rare earths sulfate and an electrodeposited Ni-Co alloy has been described. The latter step was found to be complex, due to the presence of several ions in the battery electrode materials. Electrochemical evaluation of the influence of the ions on the Ni-Co alloy deposition was carried out by cyclic voltammetry test. It was found that ions such as K+, Fe2+ and Mn2+ improved the current efficiency for the Ni-Co deposition process on a copper surface. On the other hand, Na+ and Zn2+ ions exhibited a deleterious behaviour, minimizing the values of the reduction current. The results were used to suggest the inclusion of additional steps in the process flow diagram of the recycling operation, in order to eliminate deleterious ions from the electroplating solution.

Influence of Na+ content on the structure and morphology of TiO2 nanoparticles prepared by hydrothermal transformation of alkaline titanate nanotubes

ABSTRACTThe objective of this study is to investigate the role of Na+ content in the morphology evolution of TiO2 nanoparticles prepared by hydrothermal approach. Various TiO2 morphology from 0-dimensional (0D) nanoparticles to 1-dimensional (1D) nanorods were synthesised by hydrothermally treating the alkali titanate nanotubes with different Na+ content. The XRD patterns show the phase transformation and crystallographic nature of alkali titanate nanotubes are strongly dependent on the Na+ content, the cation exchange of Na+ by H+ ion exchange affects the crystallinity of the tubes and causes disorder of the interlayers of nanotubes. The SEM and TEM images confirm that Na+ rich titanate nanotubes were thermally stable. Moreover, BET measurements revealed that the Na+ content plays an important role on the specific surface area of formed TiO2 nanoparticles. The photocatalytic activity of the TiO2 nanoparticles was characterised via the decomposition rate of an aqueous solution of methyl orange (MO) under UV light irradiation. The TiO2 nanoparticles prepared by hydrothermally treating the alkali titanate nanotubes with no Na+ content has a surface area of 55.1 m2/g with nearly 100% photodecomposition of MO in 20 min.

Transparent exopolymer particles (TEP)-associated membrane fouling at different Na+ concentrations

Membrane filtration has been widely applied for water treatment, wastewater reclamation and seawater desalination. Although extensive research work has been conducted to better understand the fouling mechanism under various conditions, little has been known about the transparent exopolymer particles (TEP)-associated membrane fouling at different Na+ concentrations. In this study, the influence of Na+ concentration on the TEP formation as well as the filtration behaviors of alginate blocks was investigated. Results showed that increasing Na+ concentration substantially reduced the TEP formation from all types of alginate blocks, thus preventing the cake layer development on the membrane surface. As a result, the TEP-associated membrane fouling was found to be kinetically slower and much less at higher Na+ level. Furthermore, filtration tests of alginate blocks at freshwater and seawater conditions were also conducted, showing that TEP-associated fouling in freshwater is much server than that in seawater at the defined conditions. This study reveals that the TEP formation is significantly influenced by the chemistry condition of bulk solution and membrane fouling is profoundly affected by the TEP levels in feed water.

Influence of Na+ and Ca2+ on flame retardancy, thermal degradation, and pyrolysis behavior of cellulose fibers

Flame-retardant cellulose–Na and cellulose–Ca fibers were successfully synthesized by grafting Na+ and Ca2+ onto cellulose fibers, and confirmed by FTIR. The combustion behavior of the fibers was assessed by the limiting oxygen index (LOI) and cone calorimeter (CONE). The maximum LOI values of cellulose–Na and cellulose–Ca fibers were 31 and 30, which are higher than that (19) of cellulose fibers. The CONE results showed that the values of heat-release rate and total heat release for cellulose–Na and cellulose–Ca fibers were significantly lower than those for cellulose fibers. The thermogravimetric analysis (TG) and differential thermogravimetric analysis (DTG) curves in the continuous and trigger modes showed that the cellulose–Na and cellulose–Ca fibers generated more residues than cellulose fibers. Thermogravimetric analysis–gas chromatography–mass spectrometry was used to detect the characteristic gases produced in the pyrolysis of cellulose–Na and cellulose–Ca fibers.

Influence of Na+, K+, Mg2 +, Ca2 +, and Fe3 + on filterability and settleability of drilling sludge

Solid–liquid separation is a vital step in drilling sludge disposal, and the filterability and settleability of drilling sludge are the main evaluating indicators for the separation process. The influence of Na+, K+, Mg2+, Ca2+, and Fe3+ on drilling sludge filterability and settleability was investigated in our research. The water content, filtration rate, supernatant volume and supernatant turbidity were measured to evaluate the filterability and settleability of drilling sludge. Meanwhile, the zeta potential, specific surface area of sludge flocs, particle size distribution and Fourier-transformed infrared spectra were employed to clarify the influencing mechanism. The experimental results showed that the filterability and settleability of drilling sludge were related to concentration and types of cations. Mg2+, Ca2+, and Fe3+ performed better than Na+, K+, and the cations with smaller hydrated radius got superior solid–liquid separation behavior at same valence. Finally, the spectra indicated that no chemical adsorption occurred between inorganic cations and drilling sludge flocs. The variation of surface charge and flocs growth after adding different inorganic cations were the reasons for the changes of the filterability and settleability.

The influence of Na+ and Ca2 + on the migration of colloids or/and ammonia nitrogen in an unsaturated zone medium

This experiment was conducted with an indoor sand-column device, the migration of colloids with the presence of Na+ and Ca2+ and the migration of ammonia nitrogen with the presence of Na+, Ca2+ or/and colloids was studied. The results showed that the migration of colloids was influenced by the ion valence state, different ions with different valence could block the migration of colloids. In addition, the blocking effect of bivalent ions was more obvious than that of monovalent ions. In the presence of Na+ and Ca2+, the Rd value of the ammonia-nitrogen migration process were 1.01 and 1.41, respectively, which indicated that bivalent ions have a greater blocking effect on ammonia-nitrogen migration than monovalent ions. Colloids could also block the ammonia-nitrogen migration, and Rd value in the ammonia-nitrogen migration process was 1.17. Moreover, the presence of Na+/colloids and Ca2+/colloids could enhance the blocking effect on the ammonia-nitrogen migration, and resulting the Rd values at 1.20 and 1.52, respectively. The cohesion of colloids caused by the compaction of its electric double layer with those ions added maybe the key causes of those blocking.

The Influence of Na(+), K(+)-ATPase on Glutamate Signaling in Neurodegenerative Diseases and Senescence.

Decreased Na+, K+-ATPase (NKA) activity causes energy deficiency, which is commonly observed in neurodegenerative diseases. The NKA is constituted of three subunits: α, β, and γ, with four distinct isoforms of the catalytic α subunit (α1−4). Genetic mutations in the ATP1A2 gene and ATP1A3 gene, encoding the α2 and α3 subunit isoforms, respectively can cause distinct neurological disorders, concurrent to impaired NKA activity. Within the central nervous system (CNS), the α2 isoform is expressed mostly in glial cells and the α3 isoform is neuron-specific. Mutations in ATP1A2 gene can result in familial hemiplegic migraine (FHM2), while mutations in the ATP1A3 gene can cause Rapid-onset dystonia-Parkinsonism (RDP) and alternating hemiplegia of childhood (AHC), as well as the cerebellar ataxia, areflexia, pescavus, optic atrophy and sensorineural hearing loss (CAPOS) syndrome. Data indicates that the central glutamatergic system is affected by mutations in the α2 isoform, however further investigations are required to establish a connection to mutations in the α3 isoform, especially given the diagnostic confusion and overlap with glutamate transporter disease. The age-related decline in brain α2∕3 activity may arise from changes in the cyclic guanosine monophosphate (cGMP) and cGMP-dependent protein kinase (PKG) pathway. Glutamate, through nitric oxide synthase (NOS), cGMP and PKG, stimulates brain α2∕3 activity, with the glutamatergic N-methyl-D-aspartate (NMDA) receptor cascade able to drive an adaptive, neuroprotective response to inflammatory and challenging stimuli, including amyloid-β. Here we review the NKA, both as an ion pump as well as a receptor that interacts with NMDA, including the role of NKA subunits mutations. Failure of the NKA-associated adaptive response mechanisms may render neurons more susceptible to degeneration over the course of aging.

Theoretical study about effects of H2O and Na+ on adsorption of CO2 on kaolinite surfaces

The density functional theory(DFT) was used to investigate the adsorptions of carbon dioxide(CO2) on kaolinite surfaces and the influences of Na+ and H2O on the adsorption. Both cluster and periodic models of kaolinite were considered. The calculated results indicate that stable complexes can be formed between adsorbed CO2 and the surfaces of kaolinite in the presence or absence of sodium cation and water molecule. The Al―O octahedral surface has a larger adsorption affinity for CO2 than the Si―O tetrahedral surface of kaolinite because the hydroxyl groups of kaolinite Al―O surface present more activity than the basal O atoms of the Si―O tetrahedral surface in the intermolecular interactions. The existence of exchangeable sodium cations exerts the significant effect on the adsorption of CO2 with the dramatic increase of the adsorption energy, while the presence of water molecule decreases the adsorption strength insignificantly. The calculated Gibbs free energies of the adsorption reveal that the adsorptions of CO2 on all the investigated kaolinite surfaces are feasible thermodynamically in the gas phase. Surface free energy was calculated to provide the predictions of the surface stability as a function of temperature.

Na(+) doping induced changes in the reduction and charge transport characteristics of Al2O3-stabilized, CuO-based materials for CO2 capture.

Chemical looping combustion (CLC) and chemical looping with oxygen uncoupling (CLOU) are emerging CO2 capture technologies that could reduce appreciably the costs associated with the capture of CO2. In CLC and CLOU, the oxygen required to combust a hydrocarbon is provided by a solid oxygen carrier. Among the transition metal oxides typically considered for CLC and CLOU, copper oxide (CuO) stands out owing to its high oxygen carrying capacity, exothermic reduction reactions and fast reduction kinetics. However, the low Tammann (sintering) temperature of CuO is a serious drawback. In this context, it has been proposed to support CuO on high Tammann temperature and low cost alumina (Al2O3), thus, reducing the morphological changes occurring over multiple CLC or CLOU redox cycles and stabilizing, in turn, the high activity of CuO. However, in CuO-Al2O3 systems, phase stabilization and avoiding the formation of the CuAl2O4 spinel is key to obtaining a material with a high redox stability and activity. Here, we report a Na(+) doping strategy to phase stabilize Al2O3-supported CuO, yielding in turn an inexpensive material with a high redox stability and CO2 capture efficiency. We also demonstrate that doping CuO-Al2O3 with Na(+) improves the oxygen uncoupling characteristics and coke resistance of the oxygen carriers. Utilizing in situ and ex situ X-ray absorption spectroscopy (XAS), the local structure of Cu and the reduction pathways of CuO were determined as a function of the Na(+) content and cycle number. Finally, using 4-point conductivity measurements, we confirm that doping of Al2O3-supported CuO with Na(+) lowers the activation energy for charge transport explaining conclusively the improved redox characteristics of the new oxygen carriers developed.

The gas phase emitter effect of lanthanum within ceramic metal halide lamps and its dependence on the La vapor pressure and operating frequency

The gas phase emitter effect increases the lamp lifetime by lowering the work function and, with it, the temperature of the tungsten electrodes of metal halide lamps especially for lamps in ceramic vessels due to their high rare earth pressures. It is generated by a monolayer on the electrode surface of electropositive atoms of certain emitter elements, which are inserted into the lamp bulb by metal iodide salts. They are vaporized, dissociated, ionized, and deposited by an emitter ion current onto the electrode surface within the cathodic phase of lamp operation with a switched-dc or ac-current. The gas phase emitter effect of La and the influence of Na on the emitter effect of La are studied by spatially and phase-resolved pyrometric measurements of the electrode tip temperature, La atom, and ion densities by optical emission spectroscopy as well as optical broadband absorption spectroscopy and arc attachment images by short time photography. An addition of Na to the lamp filling increases the La vapor pressure within the lamp considerably, resulting in an improved gas phase emitter effect of La. Furthermore, the La vapor pressure is raised by a heating of the cold spot. In this way, conditions depending on the La vapor pressure and operating frequency are identified, at which the temperature of the electrodes becomes a minimum.

Investigating the influence of Na+ and Sr2+ on the structure and solubility of SiO2-TiO2-CaO-Na2O/SrO bioactive glass.

This study was conducted to determine the influence that network modifiers, sodium (Na+) and strontium (Sr2+), have on the solubility of a SiO2-TiO2-CaO-Na2O/SrO bioactive glass. Glass characterization determined each composition had a similar structure, i.e. bridging to non-bridging oxygen ratio determined by X-ray photoelectron spectroscopy. Magic angle spinning nuclear magnetic resonance (MAS-NMR) confirmed structural similarities as each glass presented spectral shifts between -84 and -85 ppm. Differential thermal analysis and hardness testing revealed higher glass transition temperatures (Tg 591-760 °C) and hardness values (2.4-6.1 GPa) for the Sr2+ containing glasses. Additionally the Sr2+ (~250 mg/L) containing glasses displayed much lower ion release rates than the Na+ (~1,200 mg/L) containing glass analogues. With the reduction in ion release there was an associated reduction in solution pH. Cytotoxicity and cell adhesion studies were conducted using MC3T3 Osteoblasts. Each glass did not significantly reduce cell numbers and osteoblasts were found to adhere to each glass surface.

Influence of Na+ion doping on the phase change and upconversion emissions of the GdF3: Yb3+, Tm3+nanocrystals obtained from the designed molecular precursors

Bottom-up synthesis of a series of GdF3 nanocrystals (NCs) co-doped with 20 mol% Yb3+, 2 mol% Tm3+ and varying amount of Na+ ions is reported using novel molecular precursors [Ln2(TFA)6(diglyme)2] [Ln = Gd (1), Tm (2), Yb (3)] and [Na4(TFA)4(diglyme)]∞ (4) [TFA = CF3COO−; diglyme = MeO(CH2CH2O)2Me]. The single crystal X-ray structures of the new complexes 1–4, which act as excellent precursors because of the absence of water molecules and the ability of the diglyme ligand to behave as a capping reagent during decomposition to render the nanoparticles monodisperse in organic solvents, show a versatile bonding mode of the TFA (dangling η1 or bridging μ,η1,η1; μ4-η1:η1:η1:η1- and μ4-η1:η1:η1:η2 (O, F)) and diglyme (η3 or μ-η3:η1) ligands. The influence of Na+ ion doping on the phase change and upconversion emissions of these GdF3: Yb3+, Tm3+ NCs was studied and compared with the upconversion (UC) intensity of the well-known upconverting NaGdF4: Yb3+, Tm3+ NCs. Among the several UC samples studied, the GdF3: Yb3+, Tm3+ NCs with 30 mol% Na+ seemed to be the most promising as a red emitting UC phosphor, emitting more photons than the NaGdF4: Yb3+, Tm3+ UC NCs in the near IR region.