Microemulsions (MEs) have many industrial applications, where recent developments have shown that MEs can be utilized for electrochemical applications, including potentially in redox flow batteries. However, understanding the structure and dynamics of these systems, including at a surface, is needed to direct and rationally control their electrochemical behavior. While bulk solution measurements have provided insight into their structure, their assembly at an interface also impacts the electron (to the electrode) and ion (across the surfactant) charge transfer processes in the system.
View Article and Find Full Text PDFUnderstanding protein dynamics and conformational stability holds great significance in biopharmaceutical research. Hydrogen-deuterium exchange (HDX) is a quantitative methodology used to examine these fundamental properties of proteins. HDX involves measuring the exchange of solvent-accessible hydrogens with deuterium, which yields valuable insights into conformational fluctuations and conformational stability.
View Article and Find Full Text PDFThe impact of the binding, solution structure, and solution dynamics of poly(vinylidene fluoride) (PVDF) with silicon on its performance as compared to traditional graphite and LiNiMnCoO (NMC) electrode materials was explored. Through refractive index (RI) measurements, the concentration of the binder adsorbed on the surface of electrode materials during electrode processing was determined to be less than half of the potentially available material resulting in excessive free binder in solution. Using ultrasmall-angle neutron scattering (USANS) and small-angle neutron scattering (SANS), it was found that PVDF forms a conformal coating over the entirety of the silicon particle.
View Article and Find Full Text PDFDeep eutectic solvents (DESs) are an emerging class of non-aqueous solvents that are potentially scalable, easy to prepare and functionalize for many applications ranging from biomass processing to energy storage technologies. Predictive understanding of the fundamental correlations between local structure and macroscopic properties is needed to exploit the large design space and tunability of DESs for specific applications. Here, we employ a range of computational and experimental techniques that span length-scales from molecular to macroscopic and timescales from picoseconds to seconds to study the evolution of structure and dynamics in model DESs, namely Glyceline and Ethaline, starting from the parent compounds.
View Article and Find Full Text PDFThe effect of UV curing and shearing on the structure and behavior of a polyimide (PI) binder as it disperses silicon particles in a battery electrode slurry was investigated. PI dispersant effectiveness increases with UV curing time, which controls the overall binder molecular weight. The shear force during electrode casting causes higher molecular weight PI to agglomerate, resulting in battery anodes with poorly dispersed Si particles that do not cycle well.
View Article and Find Full Text PDFThis work probes the slurry architecture of a high silicon content electrode slurry with and without low molecular weight polymeric dispersants as a function of shear rate to mimic electrode casting conditions for poly(acrylic acid) (PAA) and lithium neutralized poly(acrylic acid) (LiPAA) based electrodes. Rheology coupled ultra-small angle neutron scattering (rheo-USANS) was used to examine the aggregation and agglomeration behavior of each slurry as well as the overall shape of the aggregates. The addition of dispersant has opposing effects on slurries made with PAA or LiPAA binder.
View Article and Find Full Text PDFThis work explores the complex interplay between slurry aggregation, agglomeration, and conformation (i.e. shape) of poly(acrylic acid) (PAA) and lithiated poly(acrylic acid) (LiPAA) based silicon slurries as a function of shear rate, and the resulting slurry homogeneity.
View Article and Find Full Text PDFThe use of flowing electrochemical reactors, for example, in redox flow batteries and in various electrosynthesis processes, is increasing. This technology has the potential to be of central significance in the increased deployment of renewable electricity for carbon-neutral processes. A key element of optimizing efficiency of electrochemical reactors is the combination of high solution conductivity and reagent solubility.
View Article and Find Full Text PDFA range of techniques including physical property measurements, neutron scattering experiments, molecular dynamics, and classical molecular dynamics simulations are used to probe the structural, thermodynamic, and transport properties of a deep eutectic solvent comprised of a 1:2 molar ratio of choline chloride and ethylene glycol. This mixture, known as Ethaline, has many desirable properties for use in a range of applications, and therefore, understanding its liquid structure and transport properties is of interest. Simulation results are able to capture experimental densities, diffusivities, viscosities, and structure factors extremely well.
View Article and Find Full Text PDFColloids Surf B Biointerfaces
August 2019
Understanding the development of microstructure (e.g., structures with length scales roughly 0.
View Article and Find Full Text PDFRev Sci Instrum
September 2018
High fluxes available at modern neutron and synchrotron sources have opened up a wide variety of and studies of real processes using scattering techniques. This has allowed the user community to follow chemistry in the beam, which often requires high temperatures, gas flow, etc. In this paper, we describe an integrated gas handling system for the general-purpose powder diffraction beamline Powgen at the Spallation Neutron Source.
View Article and Find Full Text PDFACS Appl Mater Interfaces
March 2018
We present a method to prepare shear thickening electrolytes consisting of silica nanoparticles in conventional liquid electrolytes with limited flocculation. These electrolytes rapidly and reversibly stiffen to solidlike behaviors in the presence of external shear or high impact, which is promising for improved lithium ion battery safety, especially in electric vehicles. However, in initial chemistries the silica nanoparticles aggregate and/or sediment in solution over time.
View Article and Find Full Text PDFThe formation of alkali-metal hydroxide layers within lamellar perovskites has been accomplished by a two-step topochemical reaction strategy. Reductive intercalation of ALaNb2O7 with alkali metal (A = K, Rb) and RbCa2Nb3O10 with Rb leads to A2LaNb2O7 and Rb2Ca2Nb3O10, respectively. Oxidative intercalation with stoichiometric amounts of water vapor, produced by the decomposition of calcium oxalate monohydrate in a sealed ampule, allows the insertion hydroxide species.
View Article and Find Full Text PDFThis study aimed to assess whether chronic administration of chondroitin sulfate (CS) affects baseline expression of cytochrome P450 isoforms and impedes the decrease in expression and activity of CYP1A2 and CYP3A6 in rabbits with a turpentine-induced inflammatory reaction (TIIR). Seven groups of 5 rabbits, 3 control groups and 4 receiving 20 mg/kg/day of CS for 20 and 30 days, were used. The rabbits of 1 control group and 2 groups receiving CS had a TIIR; finally, the rabbits of one of the control groups remained in the animal facilities for 30 days to assess the effect of time and environment on cytochrome P450.
View Article and Find Full Text PDFWe present results for the isothermal adsorption kinetics of methane, hydrogen, and tetrafluoromethane on closed-ended single-walled carbon nanotubes. In these experiments, we monitor the pressure decrease as a function of time as equilibrium is approached, after a dose of gas is added to the cell containing the nanotubes. The measurements were performed at different fractional coverages limited to the first layer.
View Article and Find Full Text PDFChondroitin sulfate is referred as a symptomatic slow-acting drug for osteoarthritis because it improves articular function, and reduces joint swelling and effusion. In addition, chondroitin sulfate prevents joint space narrowing of the knee. We hypothesized that the anti-inflammatory effect of chondroitin sulfate is associated to a decrease in the activation of mitogen-activated protein kinases (MAPK) and of the transcription factors nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1).
View Article and Find Full Text PDFUsing volumetric adsorption techniques, we have measured the adsorption of argon on Cu3(BTC)2(H2O)3, (BTC = benzene-1,3,5-tricarboxylate), a microporous metal-organic framework structure, at temperatures between 66 and 143 K. In addition to the experiments, we have used Grand Canonical Monte Carlo simulations to calculate the adsorption isotherm of argon at 87 K. Our experimental and theoretical results are compared to those of previous studies.
View Article and Find Full Text PDFPrimary Objective: To examine the role played by two interviewing methods used (spontaneous response and suggested response) in the evaluation of long-term subjective post-mild traumatic brain injury (mTBI) symptoms.
Research Design: Cohort study.
Method And Procedures: One hundred and eight adult participants were contacted for a follow-up telephone interview 12-36 months after their mTBI.
Objectives: To explore the long-term relations among sociodemographic, neurologic, clinical, and neuropsychologic variables, and vocational status in persons with mild traumatic brain injury (MTBI), and to identify the symptoms that determine whether or not these individuals return to work.
Design: Longitudinal quasi-experimental between-groups design.
Participants: Eighty-five MTBI subjects aged between 16 and 65 years.
We have measured 21 adsorption isotherms for argon on single-walled carbon nanotubes produced by laser ablation. We explored temperatures between 40 and 153 K to obtain the coverage dependence of the isosteric heat of adsorption for films in the first and second layers. Our data are compared to results obtained in computer simulation studies and to data obtained in previous experimental investigations of this system.
View Article and Find Full Text PDFWe present the combined results of a computer simulation and adsorption isotherm investigation of CF4 films on purified HiPco nanotubes. The experimental measurements found two substeps in the adsorption data. The specific surface area of the sample and the coverage dependence of the isosteric heat of adsorption of the films were determined from the measurements.
View Article and Find Full Text PDFWe have measured adsorption of xenon on purified HiPco single-walled carbon nanotubes (SWNTs) for coverages in the first layer. We compare the results on this substrate to those our group obtained in earlier measurements on lower purity arc-discharge produced nanotubes. To obtain an estimate for the binding energy of Xe, we measured five low-coverage isotherms for temperatures between 220 and 260 K.
View Article and Find Full Text PDFTo investigate how the response to a bolus and an infusion of furosemide is modulated by the rate of fluid replacement and by hypoalbuminemia, rabbits received 5 mg/kg of furosemide as a bolus or infused over 60 min, whereas diuresis was replaced with 13, 121, or 238 ml/h NaCl 0.9%/glucose 5% (50:50). Natriuretic and diuretic efficiencies were greater with the infusion than with the bolus of furosemide.
View Article and Find Full Text PDFIn humans, oral bioavailability of nifedipine has been reported to be around 60%, although the organ(s) contributing to its first-pass metabolism have not been determined. The aim of this study was to determine in vivo, in anesthetized and conscious rabbits the role of the intestine, liver, and lungs in the first-pass metabolism of nifedipine. To assess the extraction of nifedipine by the intestine, liver, and lungs, nifedipine was administered before and after each organ, and serial blood samples were withdrawn from an artery.
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