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Imipenem/Cilastatin (IPM/CS) is currently used as an embolic agent in transarterial embolization for chronic musculoskeletal pain due to its efficacy of short-term blood flow occlusion. However, due to its off-label use, the development of new materials to substitute IPM/CS is needed. Therefore, investigating the behavior of IPM/CS particles becomes crucial. In this paper, we observed the changes in particle size of IPM/CS when dissolved in phosphate-buffered saline, normal saline, iodinated contrast agent and water. The results indicated that the particle size of IPM/CS ranged from 16 to 57 µm and has fastest hydrolysis rate in iodinated contrast agent. And we analyzed the possible structure of hydrolyzed product of IPM/CS in water at room temperature and 37 ℃ using 1HNMR, HPLC. The results suggested Cilastatin is stable at both temperatures, while Imipenem hydrolyzed to produce slightly different products at different temperatures. [Display omitted] [ABSTRACT FROM AUTHOR]

The growth of silica particles synthesized by the Stöber method was investigated by the co-condensation of pyrene sulfonyl chloride (PySCl) coupled to (3-aminopropyl)triethoxysilane (APTES). Growth by monomer addition could be distinguished from growth by aggregation based on the intensity of the pyrene excimer emission of the resulting particles. The influence of the base concentration, water/ethanol ratio, solvent, temperature, and type of silica precursor was studied. At high hydrolysis rates, the growth occurred primarily by aggregation, whereas growth by monomer addition was predominant at low hydrolysis rates. The results were confirmed by evaluating the accessibility of the co-condensed pyrene moieties and by determining the porosity of the particles. [Display omitted] [ABSTRACT FROM AUTHOR]

Previous studies have shown that the dissolution alters the static intrinsic properties of mineral surfaces, such as changing the surface components or active sites, which in turn affects the floatability. In this work, the dissolution process of smithsonite with different particle sizes and its influence on the flotation behaviour were systematically investigated from a dynamic perspective of the dissolution of ions on the mineral surface. Micro-flotation experiments revealed the inhibition of the flotation of smithsonite during the early phases of dissolution, particularly in the case of the fine particle. Inductively coupled plasma optical emission spectroscopy (ICP-OES) tests, Inorganic carbon (IC) tests, and X-ray photoelectron spectroscopy (XPS) analysis indicated that the early phases of the dissolution process of smithsonite exhibited a more rapid rate of zinc ions. However, as the dissolution progressed and a state of saturation was reached, the further dissolution of carbonate inhibited that of zinc ions. Subsequent adsorption measurements and Fourier transform infrared (FTIR) analysis illuminated the transformation in flotation behaviour resulting from the surface dissolution of smithsonite, primarily by affecting the stability of the adsorption of agents. The rapid dissolution rate of ions on the surface of smithsonite led to decreased adsorption stability of (sodium oleate) NaOL and diminished floatability. This phenomenon was particularly discernible on the surface of fine particle smithsonite. This investigation advances a novel mechanism for comprehending the impact of the surface dissolution processes on the flotation behaviour of smithsonite of different particle sizes, providing a theoretical and practical reference for the flotation of fine particles and marginally soluble minerals. [Display omitted] • The dissolution of carbonate inhibits that of zinc ions on smithsonite surface. • Particle size has a strong influence on the dissolution process of smithsonite. • The surface dissolution of smithsonite changes its floatability. [ABSTRACT FROM AUTHOR]

Previous studies have shown that the dissolution alters the static intrinsic properties of mineral surfaces, such as changing the surface components or active sites, which in turn affects the floatability. In this work, the dissolution process of smithsonite with different particle sizes and its influence on the flotation behaviour were systematically investigated from a dynamic perspective of the dissolution of ions on the mineral surface. Micro-flotation experiments revealed the inhibition of the flotation of smithsonite during the early phases of dissolution, particularly in the case of the fine particle. Inductively coupled plasma optical emission spectroscopy (ICP-OES) tests, Inorganic carbon (IC) tests, and X-ray photoelectron spectroscopy (XPS) analysis indicated that the early phases of the dissolution process of smithsonite exhibited a more rapid rate of zinc ions. However, as the dissolution progressed and a state of saturation was reached, the further dissolution of carbonate inhibited that of zinc ions. Subsequent adsorption measurements and Fourier transform infrared (FTIR) analysis illuminated the transformation in flotation behaviour resulting from the surface dissolution of smithsonite, primarily by affecting the stability of the adsorption of agents. The rapid dissolution rate of ions on the surface of smithsonite led to decreased adsorption stability of (sodium oleate) NaOL and diminished floatability. This phenomenon was particularly discernible on the surface of fine particle smithsonite. This investigation advances a novel mechanism for comprehending the impact of the surface dissolution processes on the flotation behaviour of smithsonite of different particle sizes, providing a theoretical and practical reference for the flotation of fine particles and marginally soluble minerals. [Display omitted] • The dissolution of carbonate inhibits that of zinc ions on smithsonite surface. • Particle size has a strong influence on the dissolution process of smithsonite. • The surface dissolution of smithsonite changes its floatability. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract We synthesized amino acid-type photo-cleavable surfactants composed of coumarin and glycine precursors and studied the photo-switchable interfacial properties, release of active ingredients, and colloidal stability of silica particles. Photo-cleavage of the surfactants reduced their interfacial activities at the squalane/water interface. Silica particles bearing aminoethylene groups on the surface were well dispersed in an aqueous solution of the photo-cleavable anionic surfactant. The surfactants form a bilayer on the silica particles by ion complexation of the amine and carboxylic groups, and the negative charge originating from the surfactant results in electrostatic repulsion, which contributes to the dispersion stability. Ultraviolet light irradiation caused flocculation of the silica particles and the release of the coumarin derivative and glycine into the medium through photo-induced isomerization and cyclization. The new photo-cleavable surfactant systems represented controlled multiple interfacial and colloidal properties upon photoirradiation. [ABSTRACT FROM AUTHOR]

Adsorption of surfactants is one of the important feature governing interactions between particulate matters. When interactions occur between two particulates, which differ from each other, heterocoagulation takes place. This paper explains heterocoagulation of bubbles and carbonaceous metal-bearing shale particles. Heterocoagulation was experimentally studied using zeta potential, adsorption and contact angle tests. The results indicated that heterocoagulation in the presence of ionic (anionic sodium dodecyl sulfate SDS, and cationic dodecylamine hydrochloride DDA) surfactants was feasible. Based on the results, the heterocoagulation mechanism was evaluated, and thus the mechanism of shale flotation in the presence of ionic surfactants was elucidated. [ABSTRACT FROM AUTHOR]

Photochromic stimuli-responsive coordination polymers that offer on-demand molecular structure modifications are promising building blocks for next generation of multi-functional materials. Getting closer to some applications requires these materials to be in condensed phases, which is yet lacking. In this work, ≈ 300 - 450 nm colloidal particles made of a coordination polymer that includes dimethyldihydropyrene (DHP) as photoswitchable units have been synthesized. ZnDHP particles exhibit a photochromic behavior based on the reversible conversion of "closed" DHP units into "open" cyclophanediene (CDP). Ring opening in the condensed phase was triggered by visible light illumination while back-conversion was performed by either heating or irradiation with UV light. Experiments were monitored by UV–vis spectroscopy. Results showed good reversibility of the system with < 5 min back-conversion under UV irradiation. Nanostructure of the particles was studied by TEM and SAXS. Particles are made of 10 – 25 nm dense parallelepipedic nanoparticles organized into a slightly loose network. SAXS analysis demonstrates that ZnDHP particle structure is resilient to ZnCDP conversion. Finally, ability of ZnCDP-O 2 particles to release singlet oxygen during their back-conversion to ZnDHP particles is demonstrated by EPR experiments. [Display omitted] [ABSTRACT FROM AUTHOR]

We previously reported that lithium transition metal oxide, Li 1.14 (Ni 0.34 Co 0.33 Mn 0.33)O 2 (NCM), which are used as the cathode active material of lithium-ion batteries, was reacted with amine and graphene oxide (GO) to form composite particles. The reaction mechanism of the NCM and amine in the formation process, can be thought of as the ionic bonding reaction or the complex formation reaction between the transition metals and amine. This time, the composite reaction was carried out to elucidate this mechanism and to obtain hybrid composite particles with carbon black (CB), the anode active material of lithium-ion batteries. Hydrophilic substituents were introduced to CB surface by plasma treatment to create reaction points with organic materials. The hydrophilic CB became anionic in water and reacted with amine to form composite particles. Subsequent reaction with GO resulted in another composite particles. The hydrophilicity of the plasma-treated CBs was evaluated, and the composite state of the CBs, amines and GO was observed by scanning electron microscopy (SEM), and Raman spectral analysis was used to analyze the state change and film distribution of the particles. The fact that the hybrid composite particles were obtained by this method supports the mechanism that the NCM and amine were ionized and bound by electrostatic interaction. At the same time, it was found that even CBs had the means to enhance the reactivity, and organic and carbon materials could be easily combined. [Display omitted] • Ion-complex synthesis method enabled us to synthesize composite particles for lithium-ion batteries with multiple functions. • Plasma treatment improves the reactivity of the inert carbon black surface, making it easier to composite. • Raman can be used to analyze the bonding and dispersion state of carbon materials that could not be observed by IR or SEM. [ABSTRACT FROM AUTHOR]

Highlights: [•] Aromatic polyamide nanofibers with trifluoromethyl groups were prepared. [•] The nanofibers showed a strong interaction with the reaction solvent to form a gel. [•] Many small particles aggregated to form nanofibers. [•] The morphology and characteristic features depended on the reaction period. [Copyright &y& Elsevier]

Abstract: Most ordinary polystyrene (PS) microspheres without any surface modification and hard magnetic cobalt ferrite (CoFe2O4) nanoparticles were, respectively, used as large host particles and small guest particles in a heterocoagulation system. In order to achieve a regular heterocoagulation for fabricating PS–CoFe2O4 composite particles having tailored morphology, chief attention was focused on controlling over the heterocoagulation process instead of the surface modification of the polymer microspheres. A process was adopted, which included blending the two colloids at pH 1 and then, adjusting the pH value of the blending colloid to an optimal range of 2–4 under a suitable weight ratio of the two kinds of particles. The results of TEM, SEM, ζ-potential, TGA and magnetization measurements have confirmed the high density of coverage of the CoFe2O4 nanoparticles onto the surface of polystyrene particles. [Copyright &y& Elsevier]

A simple method that suppresses the oxidation and aggregation of metallic particles has been required to be developed. In the present work, metallic nickel (Ni) particles were used as a control, and silica-coating of them was performed for the suppression. Metallic Ni particles were synthesized in water exposed to air, in which nickel(II) acetate tetrahydrate, sodium borohydride, and citric acid monohydrate (Cit) were used as the Ni source, reducing reagent, and stabilizer, respectively. The metallic Ni particles with the size of ca. 33 nm were coated with silica shells with thicknesses of 14–40 nm by adding tetraethylorthosilicate (TEOS)/ethanol to the metallic Ni particle colloid solution (Ni/SiO 2). In this solution, TEOS was the silica source, and ethanol was the solvent. The morphology of Ni/SiO 2 particles was dependent on the concentrations of Cit and TEOS. Both aggregation of the metallic Ni particles and their oxidation even with annealing in air were controlled by the silica shells due to their function as a physical barrier. In addition, crystallization of the cores to metallic Ni with annealing in air was exhibited. The annealed Ni/SiO 2 particles showed paramagnetic behavior because of their small size, and the Ni/SiO 2 particles annealed at 600 °C had a saturation magnetization of 46.5 emu/g-Ni roughly comparable to that of bulk metallic Ni, which also supported that the aggregation and oxidation of metallic Ni particles were successfully controlled with the silica coating. [Display omitted] • This work studied the silica coating of metallic Ni nanoparticles and their magnetism. • The nanoparticles were fabricated by the reduction of Ni salt in water. • Silica coating was applied in silicone alkoxide ethanolic solution. • Aggregation and oxidation of the nanoparticles were controlled by silica coating. • The silica-coated nanoparticles exhibited magnetism. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes a method for Eu-coating of submicron-sized silica particles. The core silica particles with an average size of 333nm were prepared with Stöber method. The Eu-coating was performed in a water/propanol solvent in the presence of silica particles and europium acetate with a homogeneous precipitation method with the use of urea. Transmission electron microscopy (TEM) observation and measurements of ζ-potentials revealed that the silica particles were successfully coated with Eu shell. Eu shell size of the Eu-silica particles ranged from 5 to 38nm with varying concentration of silica particles. [Copyright &y& Elsevier]

Abstract: The aqueous foams prepared by mixtures of Laponite particle and nonionic surfactant (C12E4, tetraethylene glycol monododecyl ether) were studied in detail. A synergistic effect on foam stability occurs and becomes more obvious with increasing C12E4 concentration. The synergistic effect mainly comes from the adsorption of particles on the bubble surface and the formation of a three-dimensional network in the coherent phase. The enhancement of the synergistic effect is attributed to the increased adsorption density of the particles. In addition, foams prepared by silica/C12E4 and Laponite/C12E23 dispersions were compared with Laponite/C12E4 foams for better understanding. For silica/C12E4 dispersions, the synergistic effect on foam stability is found at high surfactant concentrations and just results from the increased viscosity of the dispersions. No silica particles are adsorbed at the air–water interface within the synergistic range. For Laponite/C12E23 dispersions, no synergistic effect on foam stability is found. The modified Laponite particles cannot be adsorbed on the bubble surface because of their hydrophilicity. It is assumed that the differences in the foam stability of the three systems arise from the different adsorption of surfactants on the particles. [Copyright &y& Elsevier]

Abstract: We demonstrate that it is of critical importance to prepare Janus particles with a high degree of control over the surface roughness. To elucidate information regarding the behaviour of Janus particles at an interface, we have used a gel-trapping technique coupled with metal evaporation to prepare Janus particles. Since one face is covered in gold, direct observation of the different faces at air–water and water–oil interfaces can be carried out. For particles prepared by this gel-trapping technique, the interface between hemispheres is rough and this leads to the observed orientation being random. We show that for these particles the surface roughness can dominate over the surface chemistry with regards to particle orientation. This has important implications for many of the synthetic routes towards Janus particles suggesting that, for optimum performance, it is necessary to prepare particles where the surface roughness is kept to a minimum. [Copyright &y& Elsevier]

Abstract: A sound understanding of the phenomena affecting the flow of unattached particles through the Plateau border network of a foam is essential for the accurate modelling of industrial flotation processes. One such phenomenon is the dispersion of liquid and particles perpendicular to the overall direction of flow, known as geometric dispersion. This dispersion is due to the interconnected nature of the Plateau border network within the foam, which causes the flow to split and disperse through the foam at every vertex encountered. Given the structure of the foam, the flow through the Plateau border network can be calculated and from this a geometric dispersion coefficient can be obtained. This coefficient quantifies the geometric dispersion within the foam for all flow conditions and is used as an input variable in fundamentally based flotation models. Previously the geometric dispersion coefficient has been calculated using a two-dimensional regular structure. This method has been extended here to enable the calculation of the coefficient from simulations of unattached particle flow through a three-dimensional random, monodisperse foam. The flow within the foam is modelled through the coupling of descriptions of flow on both the bulk foam and Plateau border scales. These descriptions are then combined with realistic Plateau border network structures to allow the simulation of unattached particle motion through the foam. Additionally, a geometric dispersion coefficient was predicted for the three-dimensional random, monodisperse foam, solely based on the structural properties of the network used in the particle simulations. The coefficient calculated from the simulations compares well with this predicted value, further confirming the dependence of geometric dispersion on foam structure. Specifically it is dependent on the average Plateau border length of the structure, as this varies in relation to the bubble diameter, according to the structure chosen. [Copyright &y& Elsevier]

Abstract: A preparation method for multilayered silica–Gd–silica core-shell particles is proposed. Silica particles with an average size of 30.9nm were prepared by the Stöber method. Silica–Gd core-shell particles with a size of 57.4nm were synthesized by a homogeneous precipitation method at 80°C in water/propanol solution with 27.7M H2O, 0.001M Gd(NO3)3, 0.5M urea and 1g/l polyvinylpyrrolidone in the presence of 0.001vol.% suspension of the silica particles. Succeeding silica-coating of the silica–Gd core-shell particles was performed with 0.0133M TEOS and 0.002M NaOH in the presence of a suspension of silica–Gd core-shell particles. Consequently, multilayered silica–Gd–silica core-shell particles with an average size of 71.2nm could be obtained. These particles exhibited clear enhancement in magnetic resonance images. These nanoparticles are expected to a novel magnetic resonance contrast agents. [Copyright &y& Elsevier]

Abstract: Direct measurements of the interaction forces between a spherical silica particle and a small air bubble have been conducted in aqueous electrolyte solutions by using an atomic force microscope (AFM). The silica particle was hydrophobized with a silanating reagent, and the interaction forces were measured by using several particles with different surface hydrophobicities. In the measured force curves, a repulsive force was observed at large separation distances as the particle moved towards the bubble. The origin of the repulsive force was attributed to an electrostatic double-layer force because both the particle and bubble were negatively charged. After the repulsive force, an extremely long-range attractive force acted between the surfaces. These results indicate that the intervening thin water film between the particle and bubble rapidly collapsed, resulting in the particle penetrating the bubble. The instability of the thin water film between the surfaces suggests the existence of an additional attractive force. By comparing the repulsive forces of the obtained force curves with the DLVO theory, the rupture thickness was estimated. The hydrophobicity of the particle did not significantly change the rupture thickness, whereas the pH of the solution is considered to be a critical factor. [Copyright &y& Elsevier]

Abstract: Polystyrene coating of Fe3O4 particles by dispersion polymerization was studied. The coating process was carried out in methanol with 2,2′-azobisisobutyronitrile as initiator, poly(N-vinylpyrrolidone) as stabilizer, and divinyl benzene as a cross-linking reagent. The cross-linking reagent played an important role in the dispersion polymerization. A continuous and dense polymer layer coating was formed on the Fe3O4 particles in the presence of the cross-linking reagent. The coating process was studied by sampling at fixed time intervals and the particle morphology of the samples was analyzed by TEM and the coating quantity by TG. In the presence of the cross-linking reagent, the layer coating on the Fe3O4 particles was formed by the adsorption of polymer sols that joined together to form a thick layer coating. [Copyright &y& Elsevier]

Abstract: This paper reports the preparation of freestanding two-dimensional (2D) particle arrays, which fine particles are packed in highly dense and oriented manner. To fabricate freestanding 2D arrays, sintering process of the polymer particles (3.06, 1.034, and 0.491μm diameter) was examined. The sintered 2D particle arrays on glass substrates were easily peeled off as a freestanding film by soaking into water. The freestanding 2D particle arrays were stable enough in room temperature. They show the iridescent colors due to their optical periodicity. To convince the layer number of those freestanding 2D particle arrays, fluorescent polystyrene particles were added in the arrays. Fluorescent light propagation patterns in the arrays suggest that the freestanding films were monolayers. The transmission spectra of the freestanding film were also examined. [Copyright &y& Elsevier]

Abstract: Measurement of forces between two individual particles in the millimeter and micrometer size range is difficult to accomplish and yet these are the particles that are normally encountered in many commercial systems. A cohesive force apparatus (CFA) first used by one of the authors [E.D. Shchukin, R.K. Yusupov, E.A. Amelina, P.A. Rebinder, Kolloidn. Zh. 31 (1969) 913] was modified here for studying cohesive force down to 1nN between particles of various size, shape and chemical nature under different conditions. In this work, the interaction between fused glass surfaces in solutions containing surfactants, polymers and salts was investigated by measuring the detachment force using the cohesive force apparatus. The cohesive force between glass surfaces was found to gradually decrease with increase in pH due to a corresponding increase in their negative zeta potential. Addition of salt can increase the cohesive force significantly. Interestingly, the cohesive force was observed to increase significantly with the increase of DTAB concentration because of the hydrophobic interactions between monolayers of DTAB on glass. However, the force decreased with further increase in DTAB concentration due to electrostatic repulsion between surfaces and decrease of hydrophobic interactions when DTAB bi-layers are formed. In the case of the hydrophobically modified polymer, polyvinylcaprolactam (PVCAP), the cohesive force was shown to be directly proportional to the molecular weight of the polymer and the loading force. The cohesive interactions between PEO adsorbed glass also showed the force to increase as a function of the PEO concentration, reach a maximum, and then decrease gradually, the increase being due to the reduction in the zeta potential of the glass and the decrease due to steric effect between the fully covered layers. Interaction of anionic surfactant with the pre-adsorbed PEO layer can reduce the cohesive force between the surfaces. [Copyright &y& Elsevier]

Abstract: A novel method to study the dynamics of hydrophilic solid particle interactions with the gas/aqueous surface has been developed; the gas/liquid surface oscillation was monitored using light reflection microscopy. Two modes of gas/liquid surface oscillation are observed: a high mode of oscillation during the first 0.1s and a low mode of oscillation during the last 0.4s. It has been shown that the two modes of oscillation are related with the two-stage process of particle–gas/liquid interactions; during the first stage, the particle and gas/liquid surface interact via a long-range hydrodynamic interaction. The liquid film between the particle and the gas/liquid surface decreases its thickness. During the second stage, the particle is adhered (via liquid film) to the air/aqueous surface, and the air/aqueous surface oscillates with the particle. Effects of particle size and surface tension on the frequency of oscillation of the gas/liquid surface were also studied. Two theoretical models are used to predict the high frequency and low frequency of the air/aqueous surface oscillation. [Copyright &y& Elsevier]

In 1999, we published a comprehensive survey of standards and certified reference materials for dispersed and porous solids. The present paper summarises and reports on new standards and proposals. [Copyright &y& Elsevier]

We describe here a new approach for an arrangement of many kinds of DNAs on transducers to construct a DNA chip microarray. A high-density array of sensor probes was prepared by randomly distributing a mixture of particles immobilized with various DNAs. A process for immobilization of the DNAs was separated from the assembly of the particles. The particles were arranged on the chip pattern by random fluidic self-assembly using hydrophobic interaction. [Copyright &y& Elsevier]

A thorough understanding of the aqueous uranium VI (UVI) chemistry in alkaline, sodium containing solutions is imperative to address a wide range of critical challenges in environmental engineering, including nuclear waste management. The aim of the present study was to characterise experimentally in more detail the control of pH on the removal of UVI from aqueous alkaline solutions through particle formation and on subsequent transport through porous media. We conducted first static batch experiments in the pH range between 10.5 and 12.5 containing 10 ppm UVI in 0.1 M NaCl solutions and examined the particles formed using filtration, dynamic light scattering, transition electron microscopy and X-ray powder diffraction. We found that at pH 10.5 and 11.5, between 75 and 96 % of UVI was removed from the solutions as clarkeite and studtite over a period of 48 h, forming particles with hydrodynamic diameters of 640 ± 111 nm and 837 ± 142 nm, respectively and representing aggregates of 10′s nm sized crystals randomly orientated. At pH 12.5, the formation of particles >0.2 μm became insignificant and no UVI was removed from solution. The mobility of UVI in these solutions was further studied using column experiments through quartz sand. We found that at pH 10.5 and 11.5, UVI containing particles were immobilised near the column inlet, likely due physical immobilisation of the particles (particle straining). At pH 12.5, however, UVI quantitatively eluted from the columns in the filter fraction <0.2 μm. The findings of our study reinforce a strong control of solution pH on particle size and U removal in alkaline solutions and subsequently on mobility of U through quartz porous media. [ABSTRACT FROM AUTHOR]