Search

The transition from the isotropic (I) liquid to the nematic-type (N) uniaxial phase appearing as the consequence of the elongated geometry of elements seems to be a universal phenomenon for many types of suspensions, from solid nano-rods to biological particles based colloids. Rod-like thermotropic nematogenic liquid crystalline (LC) compounds and their mixtures with a molecular solvent (Sol) can be a significant reference for this category, enabling insights into universal features. The report presents studies in 4′-methoxybenzylidene-4-n-butylaniline (MBBA) and isooctane (Sol) mixtures, for which the monotectic-type phase diagram was found. There are two biphasic regions (i) for the low (TP1, isotropic liquid-nematic coexistence), and (ii) high (TP2, liquid-liquid coexistence) concentrations of isooctane. For both domains, biphasic coexistence curves' have been discussed and parameterized. For TP2 it is related to the order parameter and diameter tests. Notable is the anomalous mean-field type behavior near the critical consolute temperature. Regarding the isotropic liquid phase, critical opalescence has been detected above both biphasic regions. For TP2 it starts ca. 20 K above the critical consolute temperature. The nature of pretransitional fluctuations in the isotropic liquid phase was tested via nonlinear dielectric effect (NDE) measurements. It is classic (mean-field) above TP1 and non-classic above the TP2 domain. The long-standing problem regarding the non-critical background effect was solved to reach this result. [ABSTRACT FROM AUTHOR]

[Display omitted] A majority of natural particles have deformable and rough surfaces. Past research indicated a lack of information for a numerical model to simulate the potential non-contact interaction between two deformable particles with uneven surfaces. The simulation of deformable particles is critical to better understanding the interaction of deformable particles in colloidal systems. We hypothesized that numerical models could simulate the deformation process of solid and hollow particles, and the constructed models could predict the impact of deformation on the interaction of rough-surfaced solid or hollow deformable particles. This work modeled the deformable solid and hollow particles with rough surface morphologies following a fractal geometry theory. Their non-contact interaction was simulated following the three-stages deformation model. Also, the impacts of surface tension, particle size, and surface roughness on the interaction of the particles were investigated. It was observed that the total potential energy of deformable solid and hollow particles followed a similar pattern under different conditions. The difference in the energy profile between solid and hollow particles is that the hollow particles generate a deeper primary minimum, and the energy barrier disappears, indicating that the hollow particles have better attachment affinity. The results show that the increased particle size will strengthen the deformability of deformable solid and hollow particles and their potential interaction, and particle size will be the most influential parameter in affecting the deformability of particles. When the particle size increased from 10 nm to 1000 nm, the deformation region of solid particles was enlarged from 5 nm to 90 nm. Nevertheless, increased surface tension would weaken the deformability of deformable solid and hollow particles, which would significantly reduce particle aggregation. The increase in the fractal dimension would reduce solid and hollow particles' deformability but increase the potential interaction energy. The controversial results could be found by increasing fractal roughness, which would improve the deformability of particles and reduce the interaction energy. The results of this study could be applied for foreseeing the deformation and interaction of deformable particles with potential applications in suspension systems, such as biological cell suspensions. [ABSTRACT FROM AUTHOR]

Red phosphorus (RP) is a promising electrochemical sensing material owing to its abundant surface groups and reactive sites. In this study, a sodium dodecyl sulfate‐assisted phosphorus‐amine approach is employed to tune surface chemistry of RP nanoparticles. During the transition of the polyphosphorus‐amine anion to RP, the cleavage of POP bond and the formation of POC bond are monitored by in situ attenuated total reflection surface‐enhanced infrared absorption spectroscopy. The formed POC bonds that are originated from the PO reactive sites are theoretically revealed with the density functional theory calculations, charge density difference, and X‐ray photoelectron spectroscopy. The energies of optimized aromatic and aliphatic POC bonds are −2.51 and −2.65 eV, respectively. To explore electrochemical sensing applications, RP nanoparticles are in situ grown on single‐walled carbon nanotube (SWCNT). Such a stable RP/SWCNT suspension is applied to fabricate the RP/SWCNT integrated arrays via a template‐filtration method. Such an array is efficient for sensitive and selective monitoring of p‐phenylenediamine on hair dyes. This study provides insights into surface chemistry of RP, its roles in electrochemical sensing applications, and an approach to produce high‐performance RP sensors at large scales. [ABSTRACT FROM AUTHOR]

An increasing number of studies in recent years have focused on the role that the gut may play in Parkinson's Disease (PD) pathogenesis, suggesting that the maintenance of a healthy gut may lead to potential treatments of the disease. The health of microbiota has been shown to be directly associated with parameters that play a potential role in PD including gut barrier integrity, immunity, function, metabolism and the correct functioning of the gut-brain axis. The gut microbiota (GM) may therefore be employed as valuable indicators for early diagnosis of PD and potential targets for preventing or treating PD symptoms. Preserving the gut homeostasis using probiotics may therefore lead to a promising treatment strategy due to their known benefits in improving constipation, motor impairments, inflammation, and neurodegeneration. However, the mechanisms underlying the effects of probiotics in PD are yet to be clarified. In this project, we have tested the efficacy of an oral probiotic suspension, Symprove™, on an established animal model of PD. Symprove™, unlike many commercially available probiotics, has been shown to be resistant to gastric acidity, improve symptoms in gastrointestinal diseases and improve gut integrity in an in vitro PD model. In this study, we used an early-stage PD rat model to determine the effect of Symprove™ on neurodegeneration and neuroinflammation in the brain and on plasma cytokine levels, GM composition and short chain fatty acid (SCFA) release. Symprove™ was shown to significantly influence both the gut and brain of the PD model. It preserved the gut integrity in the PD model, reduced plasma inflammatory markers and changed microbiota composition. The treatment also prevented the reduction in SCFAs and striatal inflammation and prevented tyrosine hydroxylase (TH)-positive cell loss by 17% compared to that observed in animals treated with placebo. We conclude that Symprove™ treatment may have a positive influence on the symptomology of early-stage PD with obvious implications for the improvement of gut integrity and possibly delaying/preventing the onset of neuroinflammation and neurodegeneration in human PD patients. [ABSTRACT FROM AUTHOR]

[Display omitted] Despite their apparent simplicity, suspensions of hard spheres in a Newtonian fluid show complex non-Newtonian behaviors and remain poorly understood. Recent works have pointed out the crucial role of interparticle contact forces in these behaviors. Here, we show that the same (polystyrene) particles, when immersed in different Newtonian solvents, show different behaviors at both the microscopic and macroscopic scales. Thanks to interparticle force measurements in each solvent together with rheological measurements, we show how the fine details of the pairwise particle interactions impact the macroscopic behavior. The rheological properties (shear thinning, shear thickening, jamming solid fraction value) of the suspensions, made up of same particles, are shown to depend on the nature of the solvent. Here, we highlight several mechanisms at the particle scale: the swelling of polymeric particles in an organic solvent, the role of colloidal repulsive forces and inertia for particles in a water solution, and the variation of the friction coefficient as a function of the load for particles immersed in silicone oils. Our study provides new quantitative data to test micromechanical models and simulations. It questions the interpretation of previous experimental works. Finally, it shows the need to systematically characterize the interparticle normal and tangential forces when studying a given suspension of hard spheres in a Newtonian fluid [ABSTRACT FROM AUTHOR]

Background: Posaconazole is widely used for the prophylaxis and treatment of invasive fungal diseases. Because of the limited and variable absorption of the initially available oral suspension, a delayed-release tablet and intravenous formulation were developed. Objective: This study aimed to characterize the pharmacokinetics, including the absolute oral bioavailability, of all posaconazole formulations in healthy volunteers. Methods: Data from 182 healthy volunteers with 3898 densely sampled posaconazole concentrations were pooled from eight phase I clinical studies on the three formulations of various single and multiple dosage regimens between 50 and 400 mg. Analysis and simulations were performed using NONMEM 7.5.0. In the covariate analysis, the influence of food (fed vs fasted), nonlinearity, and for the delayed-release tablet, comedication (antacid, ranitidine, esomeprazole, and metoclopramide) were tested. Results: A two-compartment model with respectively, four and eight absorption transit compartments, best described the profiles of the oral suspension and delayed-release tablet. For the suspension, both a food effect and a dose-dependent nonlinear bioavailability were quantified, resulting in lower bioavailability when fasted or at a higher dose. The typical bioavailability of the suspension at 100 mg and 400 mg was derived to be respectively, 17.1% and 10.1% under fasted conditions and 59.1% and 49.2% under fed conditions. The absolute bioavailability of the delayed-release tablet was 58.8% (95% confidence interval 33.2–80.4) under fasted conditions and approached complete absorption under fed conditions for dosages up to 300 mg. Food intake reduced the absorption rate constant of the suspension by 52.2% (confidence interval 45.2–59.2). The impact of comedication on the absorption of the delayed-release tablet was not statistically significant. Model-based simulations indicate that under fed conditions, the licensed dosages of the three formulations yield a steady-state trough concentration ≥ 0.7 mg/L in over 90% of healthy volunteers. About 35% of healthy volunteers who receive the licensed 300-mg delayed-release tablet under fasted conditions do not achieve this target, while for the suspension this percentage varies between 55 and 85%, depending on the dose. Conclusions: For both oral posaconazole formulations, we quantified bioavailability and absorption rate, including food effects, in healthy volunteers. The pharmacokinetic superiority of the delayed-release tablet was demonstrated under both fed and fasted conditions, compared with the oral suspension. The impact of food on the bioavailability of the delayed-release tablet was larger than anticipated, suggesting that administering the delayed-release tablet with food enhances absorption. [ABSTRACT FROM AUTHOR]

Ion-adsorption-type rare earth ores (IREOs) are an indispensable strategic resource. Rare earths can be extracted from IREOs by means of in situ leaching, which is strongly influenced by the migration of clay components. In order to clarify the effect of the interaction between mineral particles on the rare earth leaching process, the aggregation of IREO colloids was investigated in suspension after NaCl concentration and pH value were disturbed based on a light scattering method. The results show that IREO colloids are prone to unstable aggregation, which can be affected by salinity and pH in suspension. Combined with the analysis of the surface acid–base properties and the zeta potential of the IREO colloids, the long-range electrostatic attraction between mineral heterogeneous charge surfaces plays a leading role in the interaction between mineral particles. In suspension, electrolyte concentration and pH can adjust the strength of the electrostatic force and the force field overlapping between the surface double electric layers to influence the aggregation of the IREO colloids. The above conclusion can enrich and supplement the rare earth extraction theory, which has a certain guiding significance for green exploitation of IREOs. [ABSTRACT FROM AUTHOR]

Background Mycophenolate mofetil as an immunosuppressive agent is widely administered in patients with kidney disorders and following organ transplantation. The amounts of xanthan gum and sorbitol, as two excipients of mycophenolate mofetil, are influential on the final quality and stability of the suspension. Objective In this experimental study, we aim to optimize the levels of xanthan gum and sorbitol in the Mycophenolate mofetil powder. Methods A Central composite design was used to prepare the formulations. The amounts of xanthan gum and sorbitol were considered as independent variables while the sedimentation volume (F value) and concentration of active pharmaceutical ingredient (API) after preparation and after 3 months of storage at 45 Cͦ were considered as dependent variables. The samples were prepared through wet granulation process. Chromatography analysis and determination of F value and API were then performed. Results Analysis of variance showed that the increase in the amounts of xanthan up to 75 mg provided higher F value and better protection of API after 3 months by 98%, while the increase of sorbitol from 10 to 25 g had no significant effect on these variables. Optimized sample composed of 16.69 g sorbitol and 68.81 mg xanthan gum. Predicted error was desirably less than 5%. Conclusion The proposed formulation of mycophenolate mofetil powder for oral suspension with optimum amounts of xanthan gum and sorbitol has good stability. High level of xanthan gum and moderate level of sorbitol are recommended for preparing an optimal product. [ABSTRACT FROM AUTHOR]

Physicochemical properties of immunolatex, prepared by incubation of negatively charged polystyrene microparticles with polyclonal rabbit IgGs, were determined by a variety of experimental techniques. These comprised dynamic light scattering (DLS), laser Doppler velocimetry (LDV) and atomic force microscopy (AFM). The particle diffusion coefficient, the hydrodynamic diameter, the electrophoretic mobility, the zeta potential and the suspension stability were determined as a function of pH for different ionic strengths. The deposition of the immunolatex on bare and polyallylamine (PAH) functionalized mica was investigated using the microfluidic oblique impinging-jet cell, with an in situ, real-time image analysis module. The particle deposition kinetics was acquired by a direct particle enumeration procedure. The measurements enabled us to determine the range of pH where the specific deposition of the immunolatex on these substrates was absent. We argue that the obtained results have practical significance for conducting efficient flow immunoassays governed by specific antigen/antibody interactions. [ABSTRACT FROM AUTHOR]

The intended purpose of exclusionary discipline is to improve the learning environment by removing disruptive students; however, emerging evidence has suggested that these practices may have the opposite effect. Exclusionary discipline--especially policies that use suspensions as punishment for minor, developmentally normative behavioral infractions--is a known threat to suspended students' academic achievement, but few have examined whether and how these suspensions may vicariously affect nonsuspended classmates' academic achievement. This article uses a two-study approach to examine the mechanisms linking suspensions for minor infractions and educational outcomes in science (N-student = 558; N-classroom = 41; Mage = 12.83; age range = 10-16; 40% Black, 55% White, 5% other race; 51% girls; 62% eligible for free/reduced-priced lunch) and math (N-student = 1,302; N-classroom = 64; Mage = 13.00; age range = 10-16; 41% Black, 53% White, 6% other race; 50% girls; 64% eligible for free/reduced-priced lunch) classrooms among both suspended and nonsuspended students. Results showed that students who received a suspension for a minor infraction were more likely to have poorer academic achievement in both studies. In classrooms where suspensions for minor infractions were used more frequently, students had lower academic achievement, with student engagement partially mediating this relation. These results add to a growing body of school discipline literature that advocates for replacing exclusionary discipline with more developmentally responsive policies and practices. [ABSTRACT FROM AUTHOR]

We have investigated the behavior of magnetic rod-like particles and their relationship with the heat generation effect for both alternating and rotating magnetic fields, by means of Brownian dynamics simulations. As a common feature for both type of magnetic field variations, in the case of significantly strong particle-particle interaction strengths, densely-packed clusters are formed, which do not contribute to the heat generation. For the case of the alternating magnetic field, in the intermediate frequency range, linear thick chain-like clusters are formed and the constituent rod-like particles themselves tend to rotate to follow the change in the field. In contrast, for the case of the rotating field, linear clusters rotate as a whole body to respond to the magnetic field rotation. In both type of magnetic field variations, the magnetic interactions between the constituent particles in a cluster tend to function to suppress the relaxational motion of the rod-like particles, which, as a result, leads to increase in the heat generation effect in certain situations. In a relatively large frequency region, the rotating applied magnetic field gives rise to a larger heat generation effect, whereas in contrast, in the lower frequency region the alternating magnetic field yields the larger heating effect. Highlights The behavior of magnetic rod-like magnetic particles has been elucidated in the case of an alternating and a rotating magnetic field. The magnetic interactions between the constituent particles in a cluster tend to suppress the relaxation motion of the rod-like particles. The frequency and strength of a time-dependent magnetic field have complex influences on the heating effect. In a relatively large frequency region, the rotating applied magnetic field gives rise to a larger heat generation effect. In a relatively lower frequency region, the alternating magnetic field is superior to the rotating field. [ABSTRACT FROM AUTHOR]

Large scale molecular dynamics simulations are used to study drying suspensions of a binary mixture of large and small particles in explicit and implicit solvents. The solvent is first modeled explicitly and then mapped to a uniform viscous medium by matching the diffusion coefficients and the pair correlation functions of the particles. "Small-on-top" stratification of the particles, with an enrichment of the smaller ones at the receding liquid-vapor interface during drying, is observed in both models under the same drying conditions. With the implicit solvent model, we are able to model much thicker films and study the effect of the initial film thickness on the final distribution of particles in the dry film. Our results show that the degree of stratification is controlled by the Péclet number defined using the initial film thickness as the characteristic length scale. When the Péclet numbers of large and small particles are much larger than 1, the degree of "small-on-top" stratification is first enhanced and then weakens as the Péclet numbers are increased. [ABSTRACT FROM AUTHOR]

Phoretic particles self-propel using self-generated physico-chemical gradients at their surface. Within a suspension, they interact hydrodynamically by setting the fluid around them into motion and chemically by modifying the chemical background seen by their neighbours. While most phoretic systems evolve in confined environments due to buoyancy effects, most models focus on their interactions in unbounded flows. Here, we propose a first model for the interaction of phoretic particles in Hele-Shaw confinement and show that in this limit, hydrodynamic and phoretic interactions share not only the same scaling but also the same form, albeit in opposite directions. In essence, we show that phoretic interactions effectively reverse the sign of the interactions that would be obtained for swimmers interacting purely hydrodynamically. Yet, hydrodynamic interactions cannot be neglected as they significantly impact the magnitude of the interactions. This model is then used to analyse the behavior of a suspension. The suspension exhibits swirling and clustering collective modes dictated by the orientational interactions between particles, similar to hydrodynamic swimmers, but here governed by the surface properties of the phoretic particle; the reversal in the sign of the interaction tends to slow down the swimming motion of the particles. [ABSTRACT FROM AUTHOR]

In an earlier work, we discussed the possibility to realize a microrotor by immersing a chain-grafted colloidal disk in a thin film of active-particle suspension. Under certain conditions, the colloidal disk rotates unidirectionally driven by the bath active particles. Here we systematically study the role of active-particle concentration, grafting density, and chain rigidity in the phenomenon of the spontaneous symmetry breaking of the chain configurations and the unidirectional rotation of the disk. We find that high chain rigidity can help stabilize both the collective asymmetric chain configurations and the rotation of the disk, while it has a weak impact on the rotational speed/efficiency. Increasing the number of grafted chains can also stabilize the rotation but has a negative impact on the rotational speed/efficiency. Active particles power the rotation of the colloidal disk, yet their contribution saturates beyond a certain concentration. Our work provides new insights into the active systems with chain-structured objects and the design of soft/deformable micromachines. [ABSTRACT FROM AUTHOR]

Previous particle-based computer simulations have revealed a significantly more pronounced tendency of spontaneous global polar ordering in puller (contractile) microswimmer suspensions than in pusher (extensile) suspensions. We here evaluate a microscopic statistical theory to investigate the emergence of such an order through a linear instability of the disordered state. For this purpose, input concerning the orientation-dependent pair-distribution function is needed, and we discuss the corresponding approaches, particularly a heuristic variant of the Percus test-particle method applied to active systems. Our theory identifies an inherent evolution of polar order in planar systems of puller microswimmers, if mutual alignment due to hydrodynamic interactions overcomes the thermal dealignment by rotational diffusion. In our theory, the cause of orientational ordering can be traced back to the actively induced hydrodynamic rotation–translation coupling between the swimmers. Conversely, disordered pusher suspensions remain linearly stable against homogeneous polar orientational ordering. We expect that our results can be confirmed in experiments on (semi-)dilute active microswimmer suspensions, based, for instance, on biological pusher- and puller-type swimmers. [ABSTRACT FROM AUTHOR]

Dental pulp and periapical diseases are common conditions in stomatology, caused by various pathogenic microorganisms. Antimicrobial peptides, as new antibiotics, offer promising applications in the irrigation and disinfection medicaments for root canals. One patient with chronic periapical periodontitis was selected to extract the clinical pathogenic bacteria. Porphyromonas gingivalis (Pg) (ATCC 33,277), Streptococcus mutans (Sm) (ATCC 25,175), and Prevotella intermedius (Pi) (ATCC 25,611) were used as test strains. The effects of plantaricin (Pln) 149 on the biofilm formation and growth in infected root canals were evaluated by RT-PCR, laser confocal scanning microscopy, and bacterial diversity analysis. In addition, the cytotoxicity of Pln 149 (100 µg/mL) to human dental pulp stem cells (hDPSCs) was assessed using an MTT assay. Pln 149 exhibited significant inhibitory effects on Pg Sm and Pi (P < 0.05), with significant differences in the biofilm images of the laser confocal scanning microscope (P < 0.05). There were no significant differences in hDPSCs viability or proliferation between the Pln 149 and control groups. Considering the excellent antimicrobial effects and low cytotoxicity, we suggest that Pln 149 might be a promising option for root canal irrigation solutions. [ABSTRACT FROM AUTHOR]

Background: In this study, Chinese herbal compound prescriptions combined with Chinese medicine powder were evaluated for the treatment of chronic atrophic gastritis with erosion. Methods: This multi-center, randomized, positive drug control clinical trial randomly assigned 216 patients with chronic atrophic gastritis with erosion to three groups: (1) control group: aluminum plus magnesium suspension thrice per day for 4 weeks; (2) test group 1: Chinese herbal compound prescriptions twice a day plus Sanqi (Panax notoginseng) powder twice a day for 4 weeks; (3) test group 2: Chinese herbal compound prescriptions twice a day plus Sanqi (Panax notoginseng) powder and Zhebeimu (Fritillaria thunbergii Miq.) powder twice a day for 4 weeks. The primary endpoint (improvement of gastric mucosal erosion; improvement of gastric mucosal pathology) and secondary endpoints (improvement of clinical symptoms scores; improvement of the patient-reported outcome [PRO] instrument for chronic gastrointestinal diseases) were assessed using endoscopy at week 4 following the treatment. Drug-related adverse events (AEs) and adverse drug reactions (ADRs) were also compared. Results: The final analysis included 202 patients (control group, 63; test group 1, 69; test group 2, 70). At week 4, using within-group comparison, gastric mucosal erosion improved in each group following treatment with a significant difference (P < 0.05); there were no statistically significant differences in gastric mucosal erosion scores among the groups after treatment (P > 0.05); in terms of improvement of gastric mucosal erosion, the efficacy rate of the control group was 69.12%, the efficacy rate of the test group 1 was 73.24%, and the efficacy rate of the test group 2 was 69.01% and efficacy rate among the groups was not statistically significant (P > 0.05). As determined by acute inflammation, chronic inflammation, atrophy, intestinal metaplasia, and dysplasia, the pathological score (total score and the highest score) did not differ statistically among groups following treatment (P > 0.05); within the control group, the total scores of acute inflammation, chronic inflammation, atrophy, and intestinal metaplasia were significantly decreased (P < 0.05), but there was no significant improvement in dysplasia (P > 0.05); in the test group 1, chronic inflammation, atrophy, and intestinal metaplasia and dysplasia scores were significantly decreased (P < 0.05), but acute inflammation did not improve (P > 0.05); there was a significant reduction in the atrophy score in test group 2 (P < 0.05), but no improvement in the scores of acute inflammation, chronic inflammation, intestinal metaplasia, and dysplasia was observed (P > 0.05). Similarly, within the control group, the highest scores of acute inflammation, chronic inflammation, atrophy, and intestinal metaplasia were significantly decreased (P < 0.05), but there was no significant improvement in dysplasia (P > 0.05); there was a significant reduction in highest scores of atrophy, intestinal metaplasia, and dysplasia (P < 0.05) in test group 1, but the highest scores didn't not improve with acute inflammation and chronic inflammation (P > 0.05); there was a significant reduction in the highest atrophy score in test group 2 (P < 0.05), but no improvement in the highest scores of acute inflammation, chronic inflammation, intestinal metaplasia, and dysplasia was observed (P > 0.05). Compared to the control group, the main symptom scores and total symptom scores in the test groups were lower following treatment, with a statistically significant difference (P < 0.05); the analysis of covariance with center, erosion type, and group as factors was applied, and the comparison among the groups in dyspepsia, defecation, and total PRO instrument scores were statistically significant (P < 0.05). In the study period, AEs were reported in 3 (4.23%) patients in the test group 1 and 3 (4.41%) patients in the control group; ADRs were confirmed in 3 (4.23%) patients from the test group 1 and 2 (2.94%) from the control group. AEs and ADRs were not statistically significantly different among groups (AE, P = 0.2213; ADR, P = 0.2872). No serious AE or ADR was reported. Conclusions: This study has shown that both aluminum plus magnesium suspension and Chinese herbal compound prescriptions together with Panax notoginseng powder are capable of improving gastric mucosal erosion and reducing gastric mucosal pathological scores, and there were no statistically significant differences among the groups in primary endpoints, indicating that Chinese herbal therapy can achieve similar efficacy than antacids in terms of primary outcomes. The aluminum plus magnesium suspension is comparable to Chinese herbal therapy in improving atrophy and intestinal metaplasia, and is inferior to Chinese herbal therapy in improving dysplasia. In addition, the Chinese herbal therapy significantly outperforms the aluminum plus magnesium suspension in improving symptoms. Therefore, the overall clinical outcome of Chinese herbal compound prescriptions together with Panax notoginseng powder based on TCM syndrome patterns in the treatment of erosive gastritis is superior to that of antacids. Trial registration ChiCTR, ChiCTR-IPR-15005905. Registered 22 January 2015, https://www.chictr.org.cn/showproj.aspx?proj=10359 [ABSTRACT FROM AUTHOR]

The crystallization of melt emulsions is of great interest to the food, cosmetic, and pharmaceutical industries. Surfactants are used in emulsions and suspensions to stabilize the dispersed phase; thus, questions arise about the liquid–liquid and solid–liquid interfaces of the droplets or particles and the distribution of the surfactant in the different phases (continuous and dispersed phase, interface). Nuclear magnetic resonance relaxation and diffusion measurements revealed that the internal and rotational mobility of surfactant molecules at the liquid–liquid interface decreases with increasing droplet sizes. Additionally, solid–liquid interfaces have fewer surfactants than liquid–liquid interfaces as a result of the desorption of the surfactant molecules during the crystallization of the droplets. Relaxation rates of surfactant molecules in aqueous solution as single molecules, micelles, and at the liquid–liquid and solid–liquid interface are analyzed for the first time. [ABSTRACT FROM AUTHOR]

[Display omitted] Capillary suspensions feature networks of particles connected by liquid bridges, which are obtained by adding a small amount of a second immiscible liquid to a suspension. It is possible to link the network formation as well as the rheological behaviour of capillary suspensions to the intermolecular interactions of their constituents. Through a combination of experimental and numerical methods, we present a novel approach, based on Hansen solubility parameters computed from Molecular Dynamics (MD) simulations, to rationalize and predict the rheological behaviour of capillary suspensions. We investigated the formation of capillary suspensions for various combinations of bulk and secondary liquids mixed with hydrophilic silica particles. The predictions were confirmed experimentally by rheological analysis, interfacial tension measurements and microscopy (CLSM) imaging. Numerical and experimental results show that the Hansen solubility parameters theory allows to predict the formation of capillary suspensions, whose strength exponentially decays with decreasing intermolecular interactions between the secondary liquids and the dispersed particles. High immiscibility between the bulk and secondary liquid strengthens the gel up to a critical immiscibility point, above which the strength of the gel remains mostly affected by the affinity between the secondary liquids and the dispersed particles. Furthermore, we find that hydrogen-bonding and polar interactions control the formation of capillary suspensions. This simple approach can guide the selection of adequate solvents and immiscible secondary liquids, allowing an easy formulation of new particulate-based gels. [ABSTRACT FROM AUTHOR]

Due to the quality of the water entering the water purifiers, sometimes the amount of solutes and hardness in the water is so high that after a short time, these systems become clogged or full. To solve this problem. Several methods have been proposed in this study, acid injection and its effect on reverse osmosis system by wave software have been investigated. To ensure the condition and accuracy of the incoming water, the necessary tests were performed through the laboratory and the condition of the water and the number of ions and its salts were reported. By injecting acid into the inlet water, the pH value was reduced from 7.58, which is the normal pH of the water, to 5 by micrograph in 0.2 intervals, and after examination, the following results were obtained: With decreasing pH, the LSI number has a suitable decrease, so that at pH 6.1 and lower, the LSI number is negative and this indicates the lack of premature fouling. However, with this reduction, the acidic property of the treated water increases and the possibility of chemical corrosion of the industrial equipment used increases, on the other hand, by injecting acid and lowering the pH, the amount of TDS increased, which should be tried in different ways to minimize this amount. In comparison between injections of two acids performed under the same conditions, the amount of TDS at the time of H2SO4 injection at the pH limit was 10% less than the time of HCl injection. [ABSTRACT FROM AUTHOR]

A ferrocolloid is a suspension of nanometer-sized ferromagnetic particles (magnetite) in a carrier liquid (kerosene). A unique feature of a ferrocolloid is the fact that layers consisting of densely packed particles are formed near the electrode surface under the influence of an external electric field. Each layer is a liquid membrane, and its formation significantly affects the various properties of the system. For example, the development of a unique phenomenon in a ferrocolloid is self-organization (self-oscillations and autowaves). The applied external periodic force leads to a change (capture) of the frequency of the autowave process-forced synchronization of autowaves. The experimentally obtained synchronization was investigated by the method of electrically controlled interference. After multiple experiments and theoretical studies, a physical mechanism for the synchronization of the autowave process in a cell with a ferrocolloid was proposed for the first time. A mathematical model of forced synchronization of autowaves, which is described by a system of nonlinear differential equations, was proposed for the first time as well. Adding an external periodic force into the model led to a change in the frequency of autowaves; synchronization by an external force was confirmed by computational experiments. [ABSTRACT FROM AUTHOR]

Pectin is a high molecular weight polymer which is present in virtually all plants where it contributes to the cell structure. Pectin is a high valuable food ingredient widely used as a gelling agent and thickening agent with limited use in the pharmaceutical industry. The objective of this study is to evaluate the suspending properties of pectin from watermelon rind. Tragacanth was used as a standard suspending agent to which the suspending properties of pectin from watermelon rinds were compared with. The extracted pectin was subjected to phytochemical and physiochemical characterization for its safety and suitability to use as a suspending agent. Paracetamol suspensions were formulated using tragacanth concentrations of 0.5% w/v, 1% w/v, and 2% w/v and compared with paracetamol suspensions containing the same concentrations of watermelon pectin. The suspensions were all tested for their pH, sedimentation rate, sedimentation volume, flow rate, and ease of redispersibility over a period of 4 weeks. At the end of the 4-week period, all formulated suspensions had no changes in their pH values. Suspensions containing the extracted pectin had a lower rate of sedimentation and ease of redispersibility compared to that of tragacanth. In addition, their sedimentation volumes as well as flow rates were comparable to that of the tragacanth formulations. Ultimately, pectin from watermelon rind can serve as a suitable alternative to tragacanth in formulation of pharmaceutical suspensions. [ABSTRACT FROM AUTHOR]

The small‐signal dielectric and piezoelectric coefficients of paper‐derived sodium potassium niobate, K0.5Na0.5NbO3 (KNN), were compared with those of conventionally prepared samples. Results show similar functional properties of paper‐derived KNN without significantly decreasing the small‐signal piezoelectric coefficient. The structure and microstructure analysis of conventional KNN and paper‐derived KNN did not reveal any significant difference in the crystal structure and grain size. However, the temperature‐dependent inter‐ferroelectric phase transition temperature estimated from the temperature‐dependent dielectric permittivity data revealed a decrease of approximately 18°C for the paper‐derived KNN and is possibly associated with the structural and microstructural defects. This work indicates that optimizing suspension chemistry and sintering conditions will be critical to enhance the functional response of paper‐derived KNN further. Moreover, paper‐derived ceramic processing, a novel and cost‐effective additive manufacturing technology, can be potentially used to fabricate other electroceramics with a wide range of porosities and sizes as well as complex geometries and multilayer structures. [ABSTRACT FROM AUTHOR]

The effective susceptibility χ e f f of suspensions of ferromagnetic particles in a liquid was measured using inductance measurements. These measurements were used to test a model that predicts how χ e f f varies due to demagnetization, as a function of sample aspect ratio, particle packing fraction, and particle aspect ratio [R. Skomski, G. C. Hadjipanayis, and D. J. Sellmyer, IEEE Trans. Magn. 43, 2956–2958 (2007)]. For spherical particles or cylindrical particles forcibly aligned with an external magnetic field, the model can be fitted to the measured data with agreement within 13%. This model predicts suspensions of aligned, large-aspect-ratio particles should have the largest χ e f f , approaching the particle material susceptibility in the limit of large particle aspect ratio. However, χ e f f was found to be no larger than about 4 for cylindrical iron particles of various aspect ratios, close to the value obtained for spheres. This results from the random alignment of non-spherical particles relative to the magnetic field naturally found in suspensions, which increases the demagnetization effect and limits χ e f f . The contribution of random particle alignments to the demagnetization effect and χ e f f remains to be accounted for in models. [ABSTRACT FROM AUTHOR]

For highly non-uniformly flowing fluids, there are contributions to the stress related to spatial variations of the shear rate, which are commonly referred to as non-local stresses. The standard expression for the shear stress, which states that the shear stress is proportional to the shear rate, is based on a formal expansion of the stress tensor with respect to spatial gradients in the flow velocity up to leading order. Such a leading order expansion is not able to describe fluids with very rapid spatial variations of the shear rate, like in micro-fluidics devices and in shear-banding suspensions. Spatial derivatives of the shear rate then significantly contribute to the stress. Such non-local stresses have so far been introduced on a phenomenological level. In particular, a formal gradient expansion of the stress tensor beyond the above mentioned leading order contribution leads to a phenomenological formulation of non-local stresses in terms of the so-called “shear-curvature viscosity”. We derive an expression for the shear-curvature viscosity for dilute suspensions of spherical colloids and propose an effective-medium approach to extend this result to concentrated suspensions. The validity of the effective-medium prediction is confirmed by Brownian dynamics simulations on highly non-uniformly flowing fluids. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate the microgap between the abutment and implant as well as the circularity of implant platforms and associating conformational errors with bacterial microleakage in tapered connection implant systems. Materials and Methods: Four brands of implants with a tapered abutment connection were tested. Bacterial leakage was assessed using 0.3 μL of Escherichia coli suspension inoculated into the abutment screw chamber of the implants, which were then torqued and incubated at 37°C for 14 days. All specimens used for the microbiologic experiment were then cut lengthwise, and the microgap was measured at three points on each side of the sample using scanning electron microscopy (up to 5,000× magnification). Microtomography was used to assess implant platform circularity to validate the microscopic findings qualitatively. Results: Two samples from the Nobel Biocare system, four from the Ankylos (Dentsply) system, four from the Neodent (Straumann) system, and five from the Conexão system were positive for bacterial leakage, with no significant difference between groups. The Neodent system had the highest mean microgap values (5.84 ± 9.83 μm), followed by the Nobel Biocare systems (5.17 ± 4.10 μm), Ankylos (3.47 ± 3.28 μm), and Conexão (2.72 ± 3.19 μm), with no significant difference between systems. All systems showed conformational errors of circularity on microtomography images. Conclusion: The tapered connection systems evaluated herein were not able to halt bacterial leakage, nor were they free from conformational errors. [ABSTRACT FROM AUTHOR]

We report the linear rheology for dense suspensions of sterically stabilized smooth and mesoscopically rough colloids interacting as hard particles. Small amplitude oscillatory measurements reveal that rough colloids at high volume fractions exhibit storage and loss moduli that are orders of magnitude greater than smooth colloids. Frequency-concentration superposition is used to collapse the viscoelasticity data onto a master curve, where shift factors suggest a more elastic microstructure and reduced cage volume for rough particles. A combination of the mode-coupling theory, hydrodynamic modeling, and the activated hopping theory shows that these rough particles with significantly reduced localization lengths tend to become trapped in their glassy cages for extended periods of time. High-frequency data show that rough colloids, but not smooth colloids, display a transition from a free-draining to a fully lubricated state above the crossover volume fraction and, furthermore, exhibit solidlike behavior. Scaling analyses support the idea that lubrication forces between interlocking asperities are enhanced, leading to rotational constraints and stress-bearing structures that significantly elevate the viscoelasticity of dense suspensions. The results provide a framework for how particle surface topology affects the linear rheology in applications such as coatings, cement, consumer products, and shock-absorbing materials. [ABSTRACT FROM AUTHOR]

The stability and structural buildup of concrete can be evaluated by understanding the nature of the corresponding cementitious suspension using the small-amplitude oscillatory shear (SAOS) test through the time of percolation and rigidification rate, respectively. In the present study, four different cementitious suspensions--namely, 100% ordinary portland cement (OPC), OPC with 70% replacement of slag, OPC with 25% replacement of fly ash (FA), and OPC with 8% replacement of microsilica (MS)--were investigated. From the results, for OPC-based suspensions, the percolation time decreases for increasing dosages of high-range waterreducing admixture (HRWRA) at low water-binder ratios (w/b) due to their high reactivity. In contrast, the suspensions with FA and MS exhibit a higher time for the formation of the elastic network, leading to a higher time of percolation. Further, it was identified that the suspensions with slag have the highest affinity toward the HRWRA, resulting in higher dispersion and therefore higher time required for the formation of the initial elastic network. This confirms that the dispersion and reactivity of the particles in suspensions dictate the stability and the structural buildup. [ABSTRACT FROM AUTHOR]

Understanding rheological properties of dispersions of cellulose nanomaterials such as cellulose nanofiber (CNF) and cellulose nanocrystal (CNC) has received tremendous attentions from scientific and industrial viewpoints. To gain insight into the effect of aggregation-dispersion of CNF on the sol–gel state of aqueous CNF suspensions, simple turnover tests were performed for semi-dilute CNF suspensions as a function of pH and potassium chloride (KCl) concentration. Experimental results revealed that the gel state was confirmed around 20–100 mM KCl depending on pH, and the sol state was observed at higher or lower KCl concentrations. The upper and lower boundaries between gel and sol states were 20 and 80 mM around pH 4, and 50 and 120 mM around pH 7. These boundaries were discussed using the angle-dependent Derjaguin-Landau-Verwey-Overbeek (DLVO) theory for cylindrical particles. From the discussion, we presume that the gel of semi-dilute CNF suspension can be formed when the aggregation is allowed at the orientation angle between 45 and 90°. Aggregation at orientation angles below 30° can occur at high KCl concentration and might result in sol state due to the formation of aggregate with compact structure, which cannot allow the network structure in the whole suspension. [ABSTRACT FROM AUTHOR]

Using hydroxyapatite as an example, first results of research on a new additive method of manufacturing ceramic products are presented. The method consists of repeated sequential application of suspension layers with high content of powder material and their rapid 24 GHz microwave sintering. The stability of aqueous suspensions of hydroxyapatite powder with submicron particle size depending on the pH of the dispersion medium and dispersants was studied. Suspensions with a high value of the solid load mass and a fluidity sufficient to ensure the continuity of layers applied by the doctor blade method were obtained. By the method of layer-by-layer microwave sintering with a heating rate of up to 30°C/min and a maximum temperature of up to 1330°C, ceramic samples with a closed system of micron-sized pores and a density of up to 92% of the theoretical value were obtained. [ABSTRACT FROM AUTHOR]

Purpose: To compare ocular pharmacokinetics (PK), systemic absorption, and injectability of triamcinolone acetonide (TA) suprachoroidal (SC) and intravitreal (IVT) suspensions. Methods: New Zealand White (NZW) rabbits received a bilateral injection of 4 mg TA injectable suspension, TRI (TRIESENCE ®; Alcon) through either microneedle-based SC or standard IVT injection. Another group of NZW rabbits received a bilateral SC injection (4 mg) of either TRI or a proprietary TA suspension for SC use, CLS-TA (Clearside Biomedical). Blood and ocular tissues were analyzed for TA over 3 months. Separately, injectability of TRI and CLS-TA through a proprietary SC delivery system (SCS Microinjector®; Clearside Biomedical) was compared using microinjector syringe-plunger glide force measurement. Results: Suprachoroidal delivery of TRI, compared with IVT-TRI, resulted in ∼12-fold higher exposure in the retinal pigment epithelium-choroid-sclera, and comparable exposure in the retina. Conversely, SC-TRI, compared to IVT-TRI, resulted in 460-, 34-, and 22-fold lower exposure in the lens, iris-ciliary body, and vitreous humor, and negligible exposure in the aqueous humor. SC injection of either CLS-TA or TRI resulted in comparable and sustained ocular TA levels. Plasma TA levels were generally undetectable in both studies. A significantly greater and more variable glide force was measured for TRI vs. CLS-TA. Conclusions: Suprachoroidal delivery of TA enabled high and durable TA levels targeted to the chorioretina with limited anterior segment exposure. SC delivery of either CLS-TA or TRI resulted in comparable ocular PK profiles with low systemic exposure; however, CLS-TA required lower and less variable glide force than TRI, potentiating more consistent, controlled administration. [ABSTRACT FROM AUTHOR]

Quantification of leuco-indigo is most important for Aizome , Japanese indigo-dyeing; however, there has been no convenient quantitative method. This study demonstrated that normal pulse voltammetry under quiescent conditions can be used to detect leuco-indigo. As a result of quantification of leuco-indigo in the depth direction in fermenting suspensions, the steady-state concentrations of leuco-indigo showed sigmoidal profiles in the depth direction. The steady state is caused by competitive reactions of microbial reduction of indigo and autoxidation of leuco-indigo by O 2 dissolved from the air interface of the suspension. In addition, we investigated the effects of stirring the suspension and adding some nutrients to the concentration profile. The weakened activity was partially recovered by the addition of ethanol and remarkably recovered by the addition of hipolypepton or glucose. Knowledge is essential for the proper management of indigo-dye-fermenting suspensions. [ABSTRACT FROM AUTHOR]

We introduce methods for large-scale Brownian Dynamics (BD) simulation of many rigid particles of arbitrary shape suspended in a fluctuating fluid. Our method adds Brownian motion to the rigid multiblob method [F. Balboa Usabiaga et al., Commun. Appl. Math. Comput. Sci. 11(2), 217-296 (2016)] at a cost comparable to the cost of deterministic simulations. We demonstrate that we can efficiently generate deterministic and random displacements for many particles using preconditioned Krylov iterative methods, if kernel methods to efficiently compute the action of the Rotne-Prager- Yamakawa (RPY) mobility matrix and its "square" root are available for the given boundary conditions. These kernel operations can be computed with near linear scaling for periodic domains using the positively split Ewald method. Here we study particles partially confined by gravity above a noslip bottom wall using a graphical processing unit implementation of the mobility matrix-vector product, combined with a preconditioned Lanczos iteration for generating Brownian displacements. We address a major challenge in large-scale BD simulations, capturing the stochastic drift term that arises because of the configuration-dependent mobility. Unlike the widely used Fixman midpoint scheme, our methods utilize random finite differences and do not require the solution of resistance problems or the computation of the action of the inverse square root of the RPY mobility matrix. We construct two temporal schemes which are viable for large-scale simulations, an Euler-Maruyama traction scheme and a trapezoidal slip scheme, which minimize the number of mobility problems to be solved per time step while capturing the required stochastic drift terms. We validate and compare these schemes numerically by modeling suspensions of boomerang-shaped particles sedimented near a bottom wall. Using the trapezoidal scheme, we investigate the steady-state active motion in dense suspensions of confined microrollers, whose height above the wall is set by a combination of thermal noise and active flows.We find the existence of two populations of active particles, slower ones closer to the bottom and faster ones above them, and demonstrate that our method provides quantitative accuracy even with relatively coarse resolutions of the particle geometry. [ABSTRACT FROM AUTHOR]

Background: Ibuprofen a nonsteroidal anti-inflammatory drug (NSAID) derived from propionic acid utilized for its anti-inflammatory and analgesic effect was selected as an active substance for incorporation into hydrogel matrices since this active ingredient is recommended for pain therapy, rheumatoid arthritis, and osteoarthritis. Objective: The purpose of this study is to develop and optimize a suspension-type gel containing 5% ibuprofen using a full factorial design and to highlight and optimize the rheology and consistency of the products. Material and methods: In this study, the following substances were used: ibuprofen 5%, sodium carboxymethylcellulose (CMCNa, gel-forming agent), glycerol (humectant), menthol (penetration enhancer), alcohol (co-solvent), and preservative solution. Using Modde 13 software, a full factorial 22 design with 3 central points resulting in 7 formulations was applied, where the gel-forming agent and the humectant represented independent variables as follows: GI1 (CMCNa 2.5g, glycerol 2g), GI2 (CMCNa 2.5g, glycerol 3g), GI3 (CMCNa 5g, glycerol 2g), GI4 (CMCNa 5g, glycerol 3g), and three central points GI5, GI6, GI7 (CMCNa 3.75g, glycerol 2.5g). The remaining substances were added in equal amounts to all gels. The outputs selected were consistency, spreadability, shear stress, and viscosity at shear rates of 6 and 12 during both shear thinning and recovery phases. Results : The evaluated statistical parameters include R² (coefficient of determination) and Q² (measuring the predictive ability of the model), model validity, and reproducibility. All dependent variables exhibit positive predictability values, and all selected inputs highlight an R² close to 1, besides, the validity being > 0.25 indicates the lack of fit of the model. Increasing the concentration of the gel-forming agent produced a significant decrease in the spreadability and consistency while for the outputs selected during the destructuration and restoration phase (viscosity and tangential stress), a complex correlation behavior was noticed. The results obtained from the rheological test were graphically represented, indicating a pseudoplastic thixotropic flow. Conclusions: In conclusion, this study has demonstrated the success of utilizing a full factorial 22 design for the development of an optimal formulation of 5% ibuprofen gel, used in the treatment of local pain. Through the evaluation of 7 formulations, an optimal formulation with specific concentrations of sodium carboxymethylcellulose and glycerol was assessed, which provides the desired characteristics of spreadability, consistency, viscosity, and tangential stress. [ABSTRACT FROM AUTHOR]

Ruxolitinib, used in children with steroid-refractory acute graft-versus-host (GVH) disease, is currently commercially available only as a tablet adult dosage. For the paediatric population, an oral liquid would be an adapted dosage formulation. The aim of this study was to develop ruxolitinib compounded oral suspensions at 2 mg/mL by using commercial tablets in available aqueous vehicle (Inorpha) and to measure its stability at both room temperature and under refrigeration. Chemical stability of suspensions containing ruxolitinib was evaluated for 60 days based on pH, degradation, and drug content. Physical stability of the drug suspension was evaluated by visual aspect and odour. The remaining ruxolitinib concentration of the suspension was at least 95% of the initial concentration after 60 days at both temperatures. The pH, colour, and odour of the suspensions throughout the study remained unchanged with respect to the initial time point. [ABSTRACT FROM AUTHOR]

Purpose: Spray-freeze drying (SFD) incorporating diverse carbohydrates and leucine was employed to obtain dried nanosuspension of cefixime with improved dissolution profile, good dispersibility, and excellent inhalation performance. Methods: Nanoprecipitation was utilized to prepare nanoparticles (NPs). Nanosuspensions of cefixime were solidified via SFD to access inhalable microparticles. The aerosolization efficiencies were evaluated through twin stage impinger (TSI). Laser light scattering and scanning electron microscopy (SEM) provided assistance to determine the particle size/size distribution and morphology, respectively. Amorphous/ crystalline states of materials were examined via differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Release profiles of candidate preparations were evaluated. Results: The fine particle fraction (FPF) ranged from 18.96 ± 0.76 to 79.28 ± 0.45%. The highest value resulted from trehalose with NP/carrier ratio of 1:1 and leucine 20%. The particle size varied from 5.24 ± 0.97 to 10.17 ± 1.01 μm. The most and the least size distribution were achieved in mannitol and trehalose containing formulations, respectively. The majority of samples demonstrated ideally spherical morphology with diverse degrees of porosity and without needle-shaped structure. Percentages of release in F7 and F8 were 89.33 ± 0.88% and 93.54 ± 1.02%, respectively, via first 10 min. Conclusion: SFD of nanosuspensions can be established as a platform for the pulmonary delivery of poorly water-soluble molecules of cefixime. Trehalose and raffinose with a lower ratio of NP to the carrier and higher level of leucine could be introduced as favorable formulations for further respiratory delivery of cefixime. [ABSTRACT FROM AUTHOR]

Macular edema due to noninfectious uveitis is a sight-threatening complication that is routinely treated with corticosteroids. Triamcinolone acetonide injectable suspension for suprachoroidal use (Xipere™) is an alternative treatment option for patients with noninfectious uveitis-associated macular edema. This review describes the recently FDA-approved triamcinolone acetonide injectable suspension that can be injected into the suprachoroidal space. This physiological space is between the sclera and choroid. This allows for therapeutic targeting of the retina and choroid. This review highlights published clinical trials for this novel drug preparation. Suprachoroidal administration of triamcinolone acetonide has shown improvement in vision and inflammation in studies with noninfectious uveitis-associated macular edema. This unique delivery method suggests the potential to decrease side effects of anterior segment exposure such as glaucoma and cataract, but head-to-head trials are needed for further study of safety and efficacy. Additionally, there are promising prospective studies underway for utilization of the suprachoroidal space for other diseases including macular degeneration, diabetic macular edema, and ocular tumors. [ABSTRACT FROM AUTHOR]

Background. The increased content of low-grade sylvinite leads to a low indicator of product quality and the recovery factor of the main component - potassium chloride. In this regard, the problem of processing low-grade sylvinite from the Tyubegatanskoye deposit is relevant for the potash enterprise. Purpose. The aim of the study is to study the influence of technological parameters on the process of crystallization of potassium chloride and to determine the optimal conditions for obtaining potassium chloride by the halurgical method of enrichment of low-grade sylvinite of the Tyubegatanskoye deposit. Methodology. The solubility of low-grade sylvinite in water has been studied. When performing the work, standard methods of chemical analysis were used. The identification of solid phases was carried out by the method of physicochemical analysis. Originality. For the first time, the influence of time, the ratio of low-grade sylvinite to water, temperature and cooling rate on the crystallization of potassium chloride was studied, and the rheological properties of suspensions obtained by dissolving low-grade sylvinite in water were studied. Findings. Chemical and X-ray phase analyzes established the composition of the initial components and products of potassium chloride obtained by dissolving low-grade sylvinite in water. [ABSTRACT FROM AUTHOR]

Cellulose nanocrystals (CNCs) are rapidly increasingly used nanomaterials with a large surface area, outstanding mechanical characteristics, and the capacity to exhibit variable surface chemistry, allowing them to be incorporated into a variety of matrices. An examination of information from various firms on scales of tonnes per day suggests an increasing tendency for the use of CNC-based products. Here, we review recent advances in microstructural characterization of CNC-based suspensions and hydrogels utilizing imaging and rheological approaches. We demonstrate how microscopy and rheology can be utilized to adjust and improve the final macro characteristics of CNC-based systems. Novel applications, e.g., 3D printing, for CNC suspensions and gels are also introduced. Indeed, because CNC-based products show significant potential for biomedical, energy, cosmetics, filtration, and food applications, using existing characterization methods and models to fine-tune the CNC colloid properties cannot be ruled out. All references were selected from recent publications (earlier than 2010). [ABSTRACT FROM AUTHOR]

Administration of medication via enteral feeding tubes (EFT) is common in cases where patients are unable to swallow the dosage form or a patient is intubated. The SARS-CoV-2 (COVID-19, coronavirus disease 2019) epidemic created a need to rapidly evaluate potential treatment options to address the global pandemic including evaluation of azithromycin (AZM) as a mono or combination therapy. Due to the complicating medical conditions of COVID-19, in some cases patients may be unable to take medication orally and could require medication administration by alternate routes such as an EFT. The aim of this study was an in vitro assessment for the dose preparation and simulated administration of AZM suspensions, prepared from tablets and capsules, via nasogastric feeding tubes (NGT). AZM tablets and capsules were used to prepare aqueous suspensions from 250 to 2000 mg for administration via NGT. NGT between 8 and 12 French (Fr), from common materials of construction and typical lengths were evaluated. About 20 mL syringes were used with water as the diluent. The preparation and simulated NGT administration steps for AZM suspensions were evaluated in the laboratory studies and included assessment of in-use stability of the aqueous suspensions, chemical compatibility of prepared aqueous suspensions with the syringe and NGT, ease of delivery and accuracy of simulated administration. Analysis of the prepared sample solutions for assay/impurities was performed using chromatographic conditions based on the USP-NF monograph. Verification of dose preparation and simulated administration was performed for intact tablets, crushed tablets, and capsules. Aqueous suspensions prepared from intact tablets and capsules were exposed to dosing materials (enteral syringe and NGT) for a period of up to 4 hours at ambient conditions. Assessment of the ease of dose delivery and analyses of the resulting samples for assay, purity and total degradation products were performed. The laboratory studies verified a procedure to reliably prepare suspensions from AZM tablets and capsules, over a range of 250 to 2000 mg, that can be accurately administered through NGT in sizes of 8 to 12 Fr. No incompatibilities of the prepared aqueous AZM suspension with dosing materials were observed and acceptable stability was demonstrated for up to 4 hours. [ABSTRACT FROM AUTHOR]

Despite many attempts, ordered equilibrium microphases have yet to be obtained in experimental colloidal suspensions. The recent computation of the equilibrium phase diagram of a microscopic, particle-based microphase former [Zhuang et al., Phys. Rev. Lett. 116, 098301 (2016)] has nonetheless found such mesoscale assemblies to be thermodynamically stable. Here, we consider their equilibrium and assembly dynamics. At intermediate densities above the order-disorder transition, we identify four different dynamical regimes and the structural changes that underlie the dynamical crossovers from one disordered regime to the next. Below the order-disorder transition, we also find that periodic lamellae are the most dynamically accessible of the periodic microphases. Our analysis thus offers a comprehensive view of the dynamics of disordered microphases and a route to the assembly of periodic microphases in a putative well-controlled, experimental system. [ABSTRACT FROM AUTHOR]

We study different types of microswimmers moving in channels with varying cross section and thereby interacting hydrodynamically with the channel walls. Starting from the Smoluchowski equation for a dilute suspension, for which interactions among swimmers can be neglected, we derive analytic expressions for the lateral probability distribution between plane channel walls. For weakly corrugated channels, we extend the Fick-Jacobs approach to microswimmers and thereby derive an effective equation for the probability distribution along the channel axis. Two regimes arise dominated either by entropic forces due to the geometrical confinement or by the active motion. In particular, our results show that the accumulation of microswimmers at channel walls is sensitive to both the underlying swimming mechanism and the geometry of the channels. Finally, for asymmetric channel corrugation, our model predicts a rectification of microswimmers along the channel, the strength and direction of which strongly depends on the swimmer type. [ABSTRACT FROM AUTHOR]

We develop efficient numerical methods for performing many-body Brownian dynamics simulations of a recently observed fingering instability in an active suspension of colloidal rollers sedimented above a wall [M. Driscoll, B. Delmotte, M. Youssef, S. Sacanna, A. Donev, and P. Chaikin, Nat. Phys. (2016), preprint arXiv:1609.08673.We present a stochastic Adams-Bashforth integrator for the equations of Brownian dynamics, which has the same cost but is more accurate than the widely used Euler-Maruyama scheme, and use a random finite difference to capture the stochastic drift proportional to the divergence of the configuration-dependent mobility matrix. We generate the Brownian increments using a Krylov method and show that for particles confined to remain in the vicinity of a no-slip wall by gravity or active flows, the number of iterations is independent of the number of particles. Our numerical experiments with active rollers show that the thermal fluctuations set the characteristic height of the colloids above the wall, both in the initial condition and the subsequent evolution dominated by active flows. The characteristic height in turn controls the time scale and wavelength for the development of the fingering instability. [ABSTRACT FROM AUTHOR]

One of the several problems that plague majority of density functional theory calculations is their inability to properly account for long-range correlations giving rise to dispersion forces. The recently proposed many-pair expansion (MPE) [T. Zhu et al., Phys. Rev. B 93, 201108(R) (2016)] is a hierarchy of approximations that systematically corrects any deficiencies of an approximate functional to finally converge to the exact energy. This is achieved by decomposing the total density into a sum of two-electron densities and accounting for successive two-, four-, six-,: : : electron interactions. Here, we show that already low orders of MPE expansion recover the dispersion energy accurately. To this end, we employ the Pariser-Parr-Pople Hamiltonian and study the behavior of long-range interactions in trans-polyacetylene as well as stacks of ethylene and benzene molecules. We also show how convergence of the expansion is affected by electron conjugation and the choice of the density partitioning. [ABSTRACT FROM AUTHOR]

Self-propelled particles can spontaneously form dense phases from a dilute suspension in a process referred to as motility-induced phase separation. The properties of the out-of-equilibrium structures that are formed are governed by the specifics of the particle interactions and the strength of the activity. Thus far, most studies into the formation of these structures have focused on spherical colloids, dumbbells, and rod-like particles endowed with various interaction potentials. Only a few studies have examined the collective behavior of more complex particle shapes. Here, we increase the geometric complexity and use molecular dynamics simulations to consider the structures formed by triangular self-propelled particles with surface roughness. These triangles either move towards their apex or towards their base, i.e., they possess a polarity. We find that apex-directed triangles cluster more readily, more stably, and have a smoother cluster interface than their base-directed counterparts. A difference between the two polarities is in line with the results of Wensink et al. [Phys. Rev. E 89, 010302 (2014)]; however, we obtain the reversed result when it comes to clustering, namely, that apex-directed triangles cluster more successfully. We further show that reducing the surface roughness negatively impacts the stability of the base-directed structures, suggesting that their formation is in large part due to surface roughness. Our results lay a solid foundation for future experimental and computational studies into the effect of roughness on the collective dynamics of swimmers. [ABSTRACT FROM AUTHOR]

Diffusiophoresis is the process by which a colloidal particle moves in response to the concentration gradient of a chemical solute. Chemically active particles generate solute concentration gradients via surface chemical reactions which can result in their own motion--the self-diffusiophoresis of Janus particles -- and in the motion of other nearby particles -- normal down-gradient diffusiophoresis. The long-range nature of the concentration disturbance created by a reactive particle results in strong interactions among particles and can lead to the formation of clusters and even coexisting dense and dilute regions often seen in active matter systems. In this work, we present a general method to determine the many-particle solute concentration field allowing the dynamic simulation of the motion of thousands of reactive particles. With the simulation method, we first clarify and demonstrate the notion of "chemical screening," whereby the long-ranged interactions become exponentially screened, which is essential for otherwise diffusiophoretic suspensions would be unconditionally unstable. Simulations show that uniformly reactive particles, which do not self-propel, form loosely packed clusters but no coexistence is observed. The simulations also reveal that there is a stability threshold -- when the "chemical fuel" concentration is low enough, thermal Brownian motion is able to overcome diffusiophoretic attraction. Janus particles that self-propel show coexistence, but, interestingly, the stability threshold for clustering is not affected by the self-motion. [ABSTRACT FROM AUTHOR]

Electron structure features of nanopowders with composition of (Na/K)VMoO 6 have been investigated both experimentally and theoretically. The dispositions of valence edge and conduction band were determined experimentally for vacuum condition by X-ray photoelectron spectroscopy, UV–visible and impedance spectroscopy and evaluated theoretically for water solutions. The additional absorbance band in the band gap has been found for both compounds, which leads to electron conductivity at low-temperature range (250–350 °C). Nanopowders have been prepared by sol-gel method with further ground in the planetary mill. Prepared powders in water solution have formed nanosuspension with size's particle up to 100 nm for NaVMoO 6 and 400 nm for KVMoO 6 , which is hardly sedimentated. The highly effective photocatalytic ability under visible light irradiation of the prepared compounds was observed using methylene blue decomposition process. The almost full methylene blue (20 mg/L) degradation is observed during 30 min for 10 mg of the photocatalysts. The investigation of possible dye degradation pathway has showed the high depth of decomposition. [Display omitted] • The (Na/K)VMoO 6 water nano suspensions have been prepared. • The electron structure of the compounds has been determined experimentally. • The high phototcatalytic activity of (Na/K)VMoO 6 under visible light has been found. • The active radical species generated by (Na/K)VMoO 6 has been investigated. • The MB decomposition products have been defined. [ABSTRACT FROM AUTHOR]

Today, graphene oxide (GO) has gained well-deserved recognition, with its applications continuing to increase. Much of the processing of GO-based devices occurs in a dispersed form, which explains the commercialization of GO suspensions. Aging of these suspensions can, however, affect the shelf life and thus their application potential. Aging of GO preparations is often acknowledged, but no longer-term systematic study has been reported on the alteration of GO suspensions. This paper investigates high-concentration (10 mg/mL) aqueous GO suspensions over a 2-year time scale. In addition to steady shear tests, the dynamic behavior of the suspensions was studied in more detail by transient shear and frequency sweep measurements. Both the viscosity and the dynamic moduli increased with age, particularly within the first year. The results of the complementary Raman spectroscopic studies indicate that the change in the rheological behavior with aging results from a slow oxidation process occurring in the highly acidic aqueous medium during the relatively long-term storage. The (over)oxidized layers peel off spontaneously or are removed by high shear stress, resulting in increased viscosity, as it was corroborated by XRD and XPS. [ABSTRACT FROM AUTHOR]