Abstract:Hydrogen dynamics in a time range from hundreds of femtoseconds to nanoseconds can be directly analyzed using neutron spectroscopy, where information on the inelastic and quasi-elastic scattering, hereafter INS and QENS, can be obtained. In this study, we applied these techniques to understand how the nanoscale mobility of the aqueous solution of polyacrylic acid (PAA) used in conventional glass ionomer cements (GICs) changes under confinement. Combining the spectroscopic analysis with calorimetric results, we… Show more
“…Taking into account these results, the average amount of the loaded AO in the NC beads was calculated to be 5.80 ± 0.89 wt %. 16,45,46 TGA results were further substantiated by the ICP-OES measurements that revealed the Al loading of about 3.06 ± 1.62 wt %.…”
Section: ■ Results and Discussionmentioning
confidence: 75%
“…The rapid mass losses at higher temperatures may suggest notable degradation leading toward the complete decomposition of the PAA and PEI polymers while leaving only 5.17 and 6.43% mass of AO at 969 °C in PAA–AO and PAA–AO–PEI NC beads, respectively. Taking into account these results, the average amount of the loaded AO in the NC beads was calculated to be 5.80 ± 0.89 wt %. ,, TGA results were further substantiated by the ICP-OES measurements that revealed the Al loading of about 3.06 ± 1.62 wt %.…”
Emulsion template-guided strategy has been used to produce porous architectures with exquisite structure, tailored morphology, and exclusive features for ubiquitous applications. Notwithstanding, the practical water remediation is often marred by their transport-limited behavior and fragility. To circumvent these conundrums, we prepared hierarchically porous poly(acrylic acid)−alumina nanocomposite beads by solidifying the droplets of emulsions jointly stabilized by the organic surfactants and alumina nanoparticles. By virtue of their positive charge, the alumina nanoparticles got entrapped within the poly(acrylic acid) scaffolds that excluded the risk of secondary contamination typically observed with conventional nanocomposites. Being amenable to surface modification, the carboxyl moieties of the beaded polymer were further exploited to covalently tether branched polyethylenimine throughout the exterior and interior surface of the porous matrix via a grafting-to approach. The macropores expedite an active fluid flow and easier adsorbate transport throughout the functionalized nanocomposites whose overall higher density of positive charge over a certain pH range electrostatically attracts and effectively adsorbs the negatively charged Cr(VI) complexes and anionic congo red ions/molecules from water. This proof-of-concept synthetic approach and postsynthetic modification offer an improved mechanical robustness to these macrosized multifunctional nanocomposite beads for their easier processing, thereby paving the way for the point-of-use water purification technology development.
“…Taking into account these results, the average amount of the loaded AO in the NC beads was calculated to be 5.80 ± 0.89 wt %. 16,45,46 TGA results were further substantiated by the ICP-OES measurements that revealed the Al loading of about 3.06 ± 1.62 wt %.…”
Section: ■ Results and Discussionmentioning
confidence: 75%
“…The rapid mass losses at higher temperatures may suggest notable degradation leading toward the complete decomposition of the PAA and PEI polymers while leaving only 5.17 and 6.43% mass of AO at 969 °C in PAA–AO and PAA–AO–PEI NC beads, respectively. Taking into account these results, the average amount of the loaded AO in the NC beads was calculated to be 5.80 ± 0.89 wt %. ,, TGA results were further substantiated by the ICP-OES measurements that revealed the Al loading of about 3.06 ± 1.62 wt %.…”
Emulsion template-guided strategy has been used to produce porous architectures with exquisite structure, tailored morphology, and exclusive features for ubiquitous applications. Notwithstanding, the practical water remediation is often marred by their transport-limited behavior and fragility. To circumvent these conundrums, we prepared hierarchically porous poly(acrylic acid)−alumina nanocomposite beads by solidifying the droplets of emulsions jointly stabilized by the organic surfactants and alumina nanoparticles. By virtue of their positive charge, the alumina nanoparticles got entrapped within the poly(acrylic acid) scaffolds that excluded the risk of secondary contamination typically observed with conventional nanocomposites. Being amenable to surface modification, the carboxyl moieties of the beaded polymer were further exploited to covalently tether branched polyethylenimine throughout the exterior and interior surface of the porous matrix via a grafting-to approach. The macropores expedite an active fluid flow and easier adsorbate transport throughout the functionalized nanocomposites whose overall higher density of positive charge over a certain pH range electrostatically attracts and effectively adsorbs the negatively charged Cr(VI) complexes and anionic congo red ions/molecules from water. This proof-of-concept synthetic approach and postsynthetic modification offer an improved mechanical robustness to these macrosized multifunctional nanocomposite beads for their easier processing, thereby paving the way for the point-of-use water purification technology development.
“…6 also shows a theoretical curve depicting the expected behavior for purely bulk water at room temperature (black dotted line), obtained by considering the jump diffusion model, described by the expression below 21 :where D refers to the diffusion coefficient and τ 0 is the residence time. For bulk water we have used D = 2.9 × 10 −9 m 2 /s and τ 0 = 1ps 22 .Figure 6Evolution of QENS broadening (half width at half maximum – HWHM), determined from fits (see Experimental section and supplementary material) and attributed to the water molecule motion in breast cancer cells (MCF-7), as a function of Q 2 . The symbols represent the values obtained when the HWHM was allowed to vary independently at each Q-values, while the error bars represent the standard deviation.…”
Water mobility in cancer cells could be a powerful parameter to predict the progression or remission of tumors. In the present descriptive work, new insight into this concept was achieved by combining neutron scattering and thermal analyses. The results provide the first step to untangle the role played by water dynamics in breast cancer cells (MCF-7) after treatment with a chemotherapy drug. By thermal analyses, the cells were probed as micrometric reservoirs of bulk-like and confined water populations. Under this perspective we showed that the drug clearly alters the properties of the confined water. We have independently validated this idea by accessing the cellular water dynamics using inelastic neutron scattering. Finally, analysis of the quasi-elastic neutron scattering data allows us to hypothesize that, in this particular cell line, diffusion increases in the intracellular water in response to the action of the drug on the nanosecond timescale.
“…The latter benefit, to INS measurements, may be less intuitive, but, ultimately, could be of equal importance. As exemplified, e.g., by a study of dynamics of aqueous polyacrylic acid in dental restorative cements [ 64 ], as well as by our studies of breast cancer cells [ 16 ], measurements at several spectrometers, often at different facilities around the world, are often needed for sufficiently accurate characterization of both relaxational and vibrational dynamics in complex systems. As the complexity of the system under investigation increases, and especially with live systems, their evolution with time becomes increasingly probabilistic.…”
The severity of the cancer statistics around the globe and the complexity involving the behavior of cancer cells inevitably calls for contributions from multidisciplinary areas of research. As such, materials science became a powerful asset to support biological research in comprehending the macro and microscopic behavior of cancer cells and untangling factors that may contribute to their progression or remission. The contributions of cellular water dynamics in this process have always been debated and, in recent years, experimental works performed with Quasielastic neutron scattering (QENS) brought new perspectives to these discussions. In this review, we address these works and highlight the value of QENS in comprehending the role played by water molecules in tumor cells and their response to external agents, particularly chemotherapy drugs. In addition, this paper provides an overview of QENS intended for scientists with different backgrounds and comments on the possibilities to be explored with the next-generation spectrometers under construction.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
