Sodium Maleate Research Articles

Robust solid/electrolyte interphase on graphite anode to suppress lithium inventory loss in lithium-ion batteries

Lithium inventory loss is the most important reason for capacity decay of commercial lithium ion batteries. To suppress lithium inventory loss and prolong the battery cycle-life, sodium maleate (SM) is coated onto the surface of graphite active materials and act as the starting material for in-situ growth of SEI film. Microscopic studies show that the SM salt is uniformly dispersed on the graphite particles. The SM coating favors the formation of robust solid electrolyte interphase (SEI) due to its abundant carboxyl group and improves the mechanical property due to the polymerization between the unsaturated bonds. With 3.0 wt% SM coating, the first columbic efficiency, cycling stability and rate capability of the graphite anode are simultaneously improved. Electrochemical impedance spectroscopy (EIS) studies and scanning electron microscope (SEM) observations show that continuous lithium deposit on the graphite surface arising from the SEI instability during long-term electrochemical cycles is effectively suppressed. Cycle-life of the full cell assembled with LiFePO4 cathode and 3.0 wt% SM coated graphite anode is thus significantly prolonged.

Local and global conformations of flower micelles and flower necklaces formed by an amphiphilic alternating copolymer in aqueous solution

The local and global conformations of flower micelles and flower necklaces formed by the amphiphilic alternating copolymer of sodium maleate and dodecyl vinyl ether P(MAL/C12) in an aqueous solution were investigated using small-angle X-ray scattering and light scattering. Both local and global conformations for micelles of P(MAL/C12) with N01 (the degree of polymerization) 300 have been explained consistently by the flower micelle and flower necklace models with minimum-sized loops, respectively, as previously proposed.

Effect of additions of sodium hydroxide on the catalytic activity of partially deactivated skeletal nickel in reactions of the liquid-phase hydrogenation of sodium maleate in aqueous-organic media

The effect the concentration of sodium hydroxide has on the catalytic activity of skeletal nickel in reactions of the liquid-phase hydrogenation of sodium maleate in ternary methanol-water-sodium hydroxide solutions with a methanol content of 0.11 mole fractions and different concentrations of sodium hydroxide is studied. The key role of the solvent during changes in the activity of skeletal nickel in the hydrogenation reaction of sodium maleate is assumed, based on data on the redistribution of individual forms of adsorbed hydrogen.

The Role of Megalin in the Transport of Gentamicin Across BeWo Cells, an In Vitro Model of the Human Placenta.

Aminoglycosides (AG) are known to readily cross the placenta, although the mechanisms responsible for placental transport have not been characterized. Megalin is expressed in human placenta, and it is reasonable to speculate, given its role in renal AG uptake, that it is similarly involved in placental transport. However, the role of megalin in placental AG uptake has not been established. An in vitro model to study megalin-mediated placental transport has also not been previously described. The objectives of this study, therefore, were to evaluate the human choriocarcinoma (BeWo) cell line as a model to study megalin-mediated placental transport and to assess the uptake kinetics of gentamicin, an AG antibiotic, using this in vitro model. BeWo cells were grown on Transwell® plates, and megalin expression and functional activity were assessed. Uptake of (3)H-gentamicin was also evaluated in the presence and absence of megalin inhibitors. Expression of megalin protein and mRNA in BeWo cells were confirmed via immunoblot and qPCR analysis. Uptake of fluorescein isothiocyanate (FITC)-labeled bovine serum albumin (BSA) (a megalin substrate) was time-, concentration-, and temperature-dependent consistent with a transporter-mediated process. FITC-BSA uptake was also significantly reduced in the presence of unlabeled gentamicin (a megalin substrate) and sodium maleate (to induce megalin shedding) suggesting that megalin is functionally active in BeWo cells. Gentamicin uptake exhibited time and temperature dependence, saturability and Michaelis-Menten kinetics, all of which suggest a transporter-mediated process. Gentamicin uptake was also significantly reduced in the presence of the megalin inhibitors RAP and EDTA suggesting that megalin is likely involved in gentamicin uptake.

SIMULTANEOUS SPECTROPHOTOMETRIC DETERMINATION OF RABEPRAZOLE SODIUM AND DOMPERIDONE MALEATE IN CAPSULES BY CHEMOMETRIC METHODS

Simultaneous spectrophotometric determination of Rabeprazole sodium and Domperidone maleate was performed by partial least - squares (PLS) and principal componen t regression (PCR) methods do not require any priori graphical treatment of the overlapping spectra of two drugs in the mixtu re. The absorbance values in the UV - Vis spectra were measured for the 89 wavelength points (from 221 - 309) in the spectral region 20 0 - 400 nm considering the intervals of 1 nm. The calibration range was found to be 4 - 20 μ g/ml for Rabeprazole sodium , 6 - 30 μ g/ml for Domperidone maleate with a correlation coefficient of 0.9999 (PLS), 0.9999 (PCR) for Rabeprazole sodium and 0.9999 (PLS), 0.9999 (PCR) for Domperidone maleate . The validation of the multivariate methods was reali zed by analyzing the synthetic mixtures of Rabeprazole sodium and Domperidone maleate . The numerical calculations were perfo rmed with the ‘Unscrambler 10.1 X’ software. The chemometrics analysis methods were satisfactorily applied to the simultaneous determ ination of Rabeprazole sodium and Domperidone maleate in the pharmaceutical formulation.

Herb–drug pharmacokinetic interaction of artificial calculus bovis with diclofenac sodium and chlorpheniramine maleate in rats

To investigate the herb-drug pharmacokinetic interaction of artificial calculus bovis (ACB) with diclofenac sodium (DS) and chlorpheniramine maleate (CPM) in rats. A sensitive high-performance liquid chromatography coupled with tandem mass spectrometry method was developed and validated for the simultaneous determination of DS and CPM in rat plasma. The proposed method was successfully applied to compare the herb-drug pharmacokinetic interaction of ACB with DS and CPM in rats following intragastric administration. The proposed method had good linearity and no endogenous material interfered with the analytes and internal standard peaks. The lower limit of quantification of DS and CPM was 1 and 0.1 ng/ml, respectively. There was no apparent pharmacokinetic interaction between DS and CPM. Co-administration of ACB with DS noticeably increased the area under the concentration-time curve (AUC0-∞ ) and peak plasma concentration (Cmax ) of DS, while the parameters time of peak concentration (Tmax ), clearance (ClZ/F ) and apparent volume of distribution (VZ/F ) of DS significantly decreased. Meanwhile, co-administration of ACB with CPM noticeably increased the Tmax , ClZ/F and VZ/F of CPM. A marked decline in AUC0-∞ and Cmax of CPM occurred in the presence of ACB. This study indicated that co-administration of ACB with DS and CPM can result in an apparent herb-drug pharmacokinetic interaction in rats.

The concentration effect of adsorption nanocomplexes on the catalytic activity of skeletal nickel in liquid-phase hydrogenation of sodium maleate in aqueous organic environments

The effect of the concentration of adsorption nanocomplexes on the catalytic activity of skeletal nickel in liquid-phase hydrogenation of sodium maleate in 0.01 M sodium hydroxide solution containing 0.11 mol part methanol is studied. The increase in the surface concentration of hydrogen-metal and metalalcohol nanocomplexes is found to decrease the initial reaction rate and be accompanied by blockading the active catalyst sites involved in the chemical process with methanol molecules.

Controlled deactivation of a skeletal nickel catalyst with sodium silfide in liquid-phase hydrogenation reactions

The kinetics of the liquid-phase hydrogenation of sodium maleate on skeletal nickel catalysts subjected to controlled deactivation with sodium sulfide solutions was studied. The possibility of reactivating partially deactivated skeletal nickel was systematically studied for the first time, and it was found that its activity in liquid-phase hydrogenation reactions can be regulated by the introduction of a catalyst poison in small amounts into the system.

Synthesis and characterization of some chelating polymers bearing maleic acid and/or sodium maleate moieties for removal of some toxic heavy metal ions

Chelating copolymers (CCPs) bearing carboxylic acid and/or carboxylate moieties based on ethyl methacrylate in the absence and in the presence of divinyl benzene as a crosslinker were prepared via new emulsion copolymerization route. The obtained CCPs were characterized by (FT-IR, 1HNMR, TEM, GPC, and TGA). Furthermore, the prepared CCPs have been tested as adsorbents for various toxic heavy metal ions. They showed higher sorption capacities toward transition metal ions such as (Co(II) and Ni(II)) and much less sorption capacity for (Cd(II) and Pb(II)). The optimum conditions for metal ion uptake such as time, pH, and comonomer concentrations of different weight percent (wt%) as well as the sorption kinetics were investigated. A high recovery about 90–93 % was obtained using HCl as an eluent agent.

Thermodynamics of sodium maleate and chloride adsorption at an aqueous solution-gas interface

Surface tension of solutions of sodium chloride in water and sodium maleate in aqueous alkaline solutions in a wide concentration range at 298 and 303 K are measured. It is found that the dependences of surface tension of electrolyte solutions on concentration have extreme character. The obtained dependences are discussed from the standpoint of the effect of the nature of the solute and the processes of desolvation on the composition of surface layers and the surface activity of a solution. Total electrolyte adsorption isotherms are calculated using experimental surface tension and excess adsorption isotherms.

Determination of related substances concentration of compound diclofenac aodium and chlorphenamine maleate tablets

Objective To establish a high performance liquid chromatogra (HPLC) method for determining the related substances concentration ofcompound diclofenac sodium and chlorphenamine maleate tablets.Methods Diclofenac sodium and chlorphenamine maleate can be separated on HyperClone 5 μ BDS C18(4.60 mm x 150 mm )column with a mixture of (CH3)(CH2)6SO3Na 15.2mg,(C2H5)3N 0.8 ml,and distilled water 800 ml,pH adjusted to 3.3 ± 0.1 with CH3COOH,then add distilled water to 1000 ml)-CH3OH-CH3CN (25∶ 30∶ 18) as mobile phase and detected at 262 nm.Injection volume:20 μ 1.Flow rate:1.0 ml/min.Results Diclofenac sodium and chlorphenamine maleate were separated from reference substances in base-line.The dection limits were 1.18 μ g/ml.Conclusion The method has strong specificity,and is simple,accurate and reproducible.It is adapted to determine the felsted substances concentration of compound diclofenac sodium and chlorphenamine maleate tablets. Key words: Compound diclofenac sodium and chlorphenamine maleate tablets; HPLC; Related substances concentration

Unicore−Multicore Transition of the Micelle Formed by an Amphiphilic Alternating Copolymer in Aqueous Media by Changing Molecular Weight

Aggregates formed from amphiphilic alternating copolymer samples of sodium maleate and dodecyl vinyl ether (MAL/C12) of different molecular weights or (weight-average) degrees of polymerization Nw1 (= 76−5000) were characterized by light scattering and fluorescence techniques in 0.05 M aqueous NaCl at pH 10 to investigate the molecular weight dependence of the micellar structure of amphiphilic polyelectrolytes. The light scattering and fluorescence data demonstrated a unicore−multicore transition of the MAL/C12 micelle at Nw1 ≈ 300. The structures of unicore and multicore micelles of MAL/C12 copolymers formed were analyzed using the flower micelle model and the flower necklace model, respectively. The data points for unicore micelles formed from the three low-molecular-weight MAL/C12 fractions were in good agreement with the flower micelle model of the minimum loop size determined by the rigidity of the polymer main chain, which we proposed previously [KawataMacromolecules 2007, 40, 1174−1180]. On the other hand, the data points for the four high-molecular-weight MAL/C12 fractions were nicely fitted to the flower necklace model, the conformation of which was represented as the touched bead model.

Frontal Analysis Continuous Capillary Electrophoresis Study on the Interaction of an Amphiphilic Alternating Copolymer with Triton X-100

The interaction of amphiphilic alternating copolymers of sodium maleate and dodecyl vinyl ether (Mal/C12) with a nonionic surfactant, Triton X-100 (TX), was investigated by frontal analysis continuous capillary electrophoresis (FACCE). The binding isotherms obtained from FACCE data were indicative of weak cooperative interaction for all the polymers examined. The cooperative interaction was also analyzed by the Hill model, and the results were compared with the previous results on the interaction of statistical copolymers of sodium 2-acrylamido-2-methylpropanesulfonate and N-dodecylmethacrylamide with TX.

Brush border enzymes and absorptive capacity in extrahepatic portal venous obstruction in children

Portal hypertension may affect intestinal functions, brush border enzymes and absorption parameters. Information about these in extrahepatic portal venous obstruction (EHPVO) in children is limited and poorly reported. We therefore studied the brush border enzymes and absorptive capacity in EHPVO in children. The study was conducted on 52 children of EHPVO. The diagnosis of EHPVO was made on the basis of clinical presentation and ultrasound examination. All patients underwent upper gastrointestinal endoscopy. Endoscopic tissue biopsies from duodenum were taken on aluminum foils and kept immediately at -20°C for estimation of brush border enzymes. Tissue biopsies were homogenized in sodium maleate buffer, 0.1M pH 6.0, by a homogenizer and processed for the enzymes: lactase, maltase, and sucrase. Enzyme levels were compared to normal healthy controls (n=20). d-Xylose test, stool acid steatocrit for fat excretion in stools and stool alpha-1 antitrypsin were done to know about the absorptive parameters. Enzyme levels of lactase (6.21±5.67IU/mg) and sucrase (37.07±21.06IU/mg) in EHPVO group were significantly lower as compared to lactase (23.32±10.48IU/mg) and sucrase (95.96±46.55IU/mg) in normal healthy controls. Maltase levels were lower, but difference was not statistically significant in EHPVO group (56.90±28.65IU/mg) as compared to normal controls (63.28±22.88IU/mg). There was no significant difference of urinary d-xylose and stool fat in patients with normal or short stature EHPVO patients. EHPVO leads to decrease in levels of brush border enzymes in small bowel but their absorption capacity remains normal.

Radiowave Dielectric Properties of Sodium Maleate Copolymers in Aqueous Solutions in Light of a Scaling Approach

The concentration dependence of the dielectric properties of aqueous solutions of sodium maleate copolymers with comonomers of different hydrophobicities have been investigated by means of frequency domain dielectric spectroscopy in the frequency range from 1 kHz to 2 GHz. The dielectric relaxation falling between the process at low frequencies (polarization involving the whole polymer chain) and the one at high frequencies (polarization of the bulk aqueous phase) has been analyzed in light of the scaling properties of polyelectrolyte solutions. Within this framework, the dielectric properties are governed by two characteristic lengths, the distance R(cm) between chains in the dilute regime and the correlation length xi in the semidilute regime. We find that, for both these regimes, the exponents of the scaling laws, which describe the dielectric increment Deltaepsilon and the relaxation time tau(ion) are in a reasonably good agreement with the ones experimentally observed. This analysis gives further support to the scaling approach of the dynamic behavior of polyelectrolytes, appearing very suitable to modeling our dielectric results.

Macromolecular Recognition of Cyclodextrin: Inversion of Selectivity of β‐Cyclodextrin toward Adamantyl Groups Induced by Macromolecular Chains

Interaction of β-cyclodextrin (β-CD) with alternating copolymers (pAdMA and pAdPhMA) of sodium maleate with adamantyl (Ad) and with adamantylphenyl (AdPh) vinyl ether has been investigated by several NMR techniques. Comparing the apparent association constants (K) for the polymers with the K for the model compounds, which are determined by the analysis of (1) H NMR and isothermal titration calorimetry data, respectively, the selectivities of β-CD toward Ad and AdPh moieties are contrasting for the model and polymer systems. This phenomenon is described by circular dichroism and 2D NMR as follows; the most stable inclusion complex for the β-CD/AdPh model system is extremely destabilized for the corresponding polymer system because of competition with hydrophobic interaction between neighboring AdPh moieties.

Development of New Validated Spectrophotometric Method for Simultaneous Estimation of Rabeprazole Sodium and Domperidone Maleate in Bulk and Capsule Dosage Form

A method for the simultaneous determination of rabeprazole sodium and domperidone maleate in bulk and capsule dosage form was developed. The method employs formation and solving of simultaneous equations using 259.4 and 284.4 nm as two analytical wavelengths. The absorbance maxima of rabeprazole sodium and domperidone maleate were found to be 259.4 nm and 284.4 nm respectively in 0.1N H 2 SO 4 . The linearity range lies between 4-40 μg/ml for rabeprazole sodium and 5-35 μg/ml for domperidone maleate at their respective wavelength. Both the drugs obey Beer's law. The molar absorptivity and sandell's sensitivity were found to be 8.87×103and 0.0431 respectively for Rabeprazole sodium and for Domperidone maleate 9.99×103 and 0.0427 respectively. The recovery studies confirmed the accuracy of the developed method.

Specific biofunctional performances of the hydroxyapatite–sodium maleate copolymer hybrid coating nanostructures evaluated by in vitro studies

The nanohybrid structures consisting of hydroxyapatite (HA) and sodium maleate-vinyl acetate copolymer (MP) deposited by Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique on Ti surfaces were investigated for specific biological qualities required in bone implantology. The data from in vitro studies demonstrated that human primary osteoblasts (OBs) firmly adhered to Ti coated with HA-MP as indicated by cytoskeleton and vinculin dynamics. OBs spread onto biomaterial surface and formed groups of cells which during their biosynthetic activity expressed OB phenotype specific markers (collagen and non-collagenous proteins) and underwent controlled proliferation.

Synthesis and photophysical study of silver nanoparticles stabilized by unsaturated dicarboxylates

Solution-phase synthesis of nanometer-sized silver particles is reported by sodium borohydride reduction of AgNO 3. Two isomeric dicarboxylates (sodium maleate and sodium fumarate) have been used as stabilizing agents. The dicarboxylate-stabilized silver nanoparticles are characterized by UV–vis spectroscopy, high-resolution transmission electron microscopy (HR-TEM) and fourier transform infrared (FT-IR) spectroscopy. A qualitative comparison is made between the UV–vis spectral characteristic of the SPR band and the simulated curve obtained from modified Mie's theory. Silver nanoparticles prepared using these two isomeric dicarboxylates show intense fluorescence in the visible region. DFT with hybrid functional (B3LYP)-based frequency (IR) calculation of both the dicarboxylates and the respective nanoparticles are in good agreement with the experimental IR frequency. On the basis of this calculation a model has been proposed for the stabilization of silver nanoparticles by these two isomeric dicarboxylate anions.

The kinetics of liquid-phase hydrogenation of sodium maleate by hydrogen adsorbed on the surface of Raney nickel

The kinetics of liquid-phase hydrogenation of sodium maleate by hydrogen adsorbed on the surface of Raney nickel in aqueous solutions was studied by the adsorption-calorimetric method. The kinetic reaction parameters in the surface layer were determined over a broad range of surface coverages. It was proved that a kinetic description in terms of classic kinetic approaches was formal and did not reveal the essence of the process. A description of kinetic reactions in terms of the Elovich equation for uniformly inho-mogeneous surfaces was better grounded physically.