Sink or float? Characterization of shell-stabilized bulk nanobubbles using a resonant mass measurement technique.

SpiralDesigner: An AI-assisted design interface for efficient separation of neutrally buoyant and non-buoyant particles using spiral microfluidic devices

Comparison of Submicron Particle Counting Methods with a Heat Stressed Monoclonal Antibody: Effect of Electrolytes and Implications on Sample Preparation

Evaluation of Incremental Siliconization Levels on Soluble Aggregates, Submicron and Subvisible Particles in a Prefilled Syringe Product

Effects of Syringe Material and Silicone Oil Lubrication on the Stability of Pharmaceutical Proteins

Lipid-shelled magnetic bubbles are widely researched for potential applications as multi-functional contrast agents for ultrasound and magnetic resonance imaging and for drug delivery applications. In this study, we prepared nano-sized magnetic bubbles using a magnetic lipid solution created by first forming a homogeneous phospholipid solution in phosphate buffered saline (PBS) containing glycerol and propylene glycol and followed by adding superparamagnetic iron oxide nanoparticles with a diameter of 10 nm. Bubbles were generated by mechanical agitation using a dental amalgamator, and magnetic nanobubbles were isolated by centrifugation at 50 g for 5 min. Prepared magnetic nanobubbles had a mean diameter of 308 ± 105 nm and a concentration of (1.68 x 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sup> bubbles/mL), as determined by resonant mass measurement. Stability of the magnetic nanobubbles over time was evaluated by measuring the acoustic signal decay. Magnetic nanobubbles showed a 27% and 83% signal decay after 1 and 2 h at room temperature, respectively. The response of the magnetic nanobubbles to a magnetic field was examined by measuring T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> relaxation times at different bubble/iron concentrations. Magnetic nanobubbles showed an r <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> relaxivity of 144.6 mM <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> . This study demonstrates feasibility of preparing magnetic nanobubbles using a simple self-assembly process. The constructs could be more effective in multimodality molecular imaging and extravascular drug delivery compared to magnetic microbubbles, due to their sub-micron size.

Variables Impacting Silicone Oil Migration and Biologics in Prefilled Syringes

The article is devoted to the study of dilution effect on the blood plasma particle concentrations and sizes, obtained by dynamic light scattering methods. It is found that log-log scale plots of the relation between particle concentrations and radii are linear for both undiluted and 10- and 100-fold diluted thawed blood plasma samples in the particle size range from 1 to 300 nm for the spherical shape model. This indicates the applicability of Mie theory and its approximations and Stokes-Einstein equation for describing of light scattering by the particles in undiluted plasma. It is shown also that the use of the cylindrical particle shape model of extends the range of the linear relation between particle concentrations and sizes up to 10000 nm.

Unclean air discharge refers to the discharge phenomenon of a large number of polluting gases, droplets or solid particles floating in the air, which will cause insulation breakdown and safety accidents for the power transmission equipment that have been left outdoors for a long time. In order to investigate the effects of particle concentration, particle size and dielectric constant on DC breakdown characteristics of unclean air gap, a self‐made discharge chamber was designed in this study. The air was filtered and passed into the discharge chamber to remove the influence of impurities contained in the air on the experimental results. Then, solid particles with different concentration, particle size and particle dielectric constant were added to the discharge chamber to carry out the DC positive polarity breakdown characteristic experiment. The experimental results show that compared with dry clean air, the presence of solid particle increases the breakdown voltage of the gap, and the increase proportion of breakdown voltage is related to the particle concentration, particle size and particle dielectric constant. With the same particle type and particle size, the increase proportion of breakdown voltage increases with the higher concentration, which up to 10.49%. For further investigating, the fluid mechanics model was selected to simulate the process of streamer discharge in unclean air. The results show that compared with dry clean air, the presence of particles enhances the gap discharge ionisation process, but also enhances the adsorption of particles, and the latter has stronger effect than the former, thus increases the gap breakdown voltage. At the same time, the enhancement of adsorption effect increases the electric field intensity of the gap and speeds up the development process of streamer discharge.

Electrospray ionization multi-stage tandem mass spectrometry (ESI-MS(n)) and liquid chromatography coupled with sequential mass spectrometry (LC/MS(n)) were applied to identify trace-level phenanthroindolizidine alkaloids in crude extracts from Tylophora atrofolliculata. Based on the relationship between the characteristic fragmentation reactions and the structural features of related compounds of known structure from this plant, the bioactive crude extract was analyzed in detail by positive and negative ion ESI-MS(n), LC/UV-MS and LC/MS(n) techniques. A total of nine constituents in the crude extract were identified rapidly, including several isomers; seven of these constituents are new and two are known compounds. The structures of four of these constituents were subsequently confirmed by nuclear magnetic resonance (NMR) and accurate mass measurements using high-resolution fast-atom bombardment mass spectrometry (FAB-HRMS).

The effect of particle properties on the rheological behaviour of carrot-derived suspensions was investigated systematically. Hereto, a range of relatively monodisperse suspensions, with varying average particle sizes (∼73, 176, 262 and 369 μm) and pulp contents (from 30 to 65 wt.%), was prepared by the reconstitution of carrot tissue particles in water. Suspensions with average particle size of ∼73 μm consisted of cell fragments, whereas suspensions with larger particle sizes contained mainly cell clusters of which the cell number increased with increasing particle size. The rheological characteristics showed that the carrot-derived suspensions have a non-Newtonian behaviour with a yield stress, depending on particle concentration, size and type. The network structure of all suspensions could be described as a weak gel. Increase in yield stress and storage modulus with particle concentration could be fitted to a power law model. A unique linear relation was found between the yield stress and the plateau modulus, independent of the particle size and type. Particle concentration, size and type appeared to be key structural parameters controlling the rheology of these carrot-derived suspensions. When comparing the rheological behaviour of the reconstituted suspensions with the original carrot purée of similar average diameter and pulp content, the network structure (measured as yield stress or storage modulus) in carrot purée was weaker, which may be attributed to the broader particle size distribution.

In the present study, a particle focusing technique functioning based on the cumulative effects of gravity and negative dielectrophoresis (nDEP) is developed for digital microfluidic (DMF) systems. This technique works using the conventional electrodes used for droplet manipulation without a need for geometrical modification. Particle manipulation is performed by applying an AC voltage to the electrode above which there is the droplet containing the non-buoyant particles. The particles sediment due to the difference between the gravitational and the vertical component of the nDEP forces, while the horizontal component of the nDEP force concentrates them on the center of the electrode. Therefore, the magnitude of the voltage must be kept within an effective range to have simultaneous effects of sedimentation (dominated by gravity) and concentration (due to the horizontal component of the nDEP force). The physics of the phenomenon is explained using simulation. The effects of the magnitude of the applied voltage, the particle size and density, and the electrode size on the focusing behavior of the particles are studied. Finally, a potential application of the present technique is illustrated for particle concentration in DMF.

Long–range transport of soil dust and smoke pollution in the South Asian region

The influence of particle size and concentration combined with pH on coagulation mechanisms

Electrochemical characteristics of dip-coated poly (2-cinnamoylethyl methacrylate) (PCEMA) films on Au surfaces

Large Scale Integrated Testing (LSIT) is being planned by Bechtel National, Inc. to address uncertainties in the full scale mixing performance of the Hanford Waste Treatment and Immobilization Plant (WTP). Testing will use simulated waste rather than actual Hanford waste. Therefore, the use of suitable simulants is critical to achieving the goals of the test program. External review boards have raised questions regarding the overall representativeness of simulants used in previous mixing tests. Accordingly, WTP requested the Savannah River National Laboratory (SRNL) to assist with development of simulants for use in LSIT. Among the first tasks assigned to SRNL was to develop a list of waste properties that matter to pulse-jet mixer (PJM) mixing of WTP tanks. This report satisfies Commitment 5.2.3.1 of the Department of Energy Implementation Plan for Defense Nuclear Facilities Safety Board Recommendation 2010-2: physical properties important to mixing and scaling. In support of waste simulant development, the following two objectives are the focus of this report: (1) Assess physical and chemical properties important to the testing and development of mixing scaling relationships; (2) Identify the governing properties and associated ranges for LSIT to achieve the Newtonian and non-Newtonian test objectives. This includes the properties to support testing of sampling and heel management systems. The test objectives for LSIT relate to transfer and pump out of solid particles, prototypic integrated operations, sparger operation, PJM controllability, vessel level/density measurement accuracy, sampling, heel management, PJM restart, design and safety margin, Computational Fluid Dynamics (CFD) Verification and Validation (V and V) and comparison, performance testing and scaling, and high temperature operation. The slurry properties that are most important to Performance Testing and Scaling depend on the test objective and rheological classification of the slurry (i.e., Newtonian or non-Newtonian). The most important properties for testing with Newtonian slurries are the Archimedes number distribution and the particle concentration. For some test objectives, the shear strength is important. In the testing to collect data for CFD V and V and CFD comparison, the liquid density and liquid viscosity are important. In the high temperature testing, the liquid density and liquid viscosity are important. The Archimedes number distribution combines effects of particle size distribution, solid-liquid density difference, and kinematic viscosity. The most important properties for testing with non-Newtonian slurries are the slurry yield stress, the slurry consistency, and the shear strength. The solid-liquid density difference and the particle size are also important. It is also important to match multiple properties within the same simulant to achieve behavior representative of the waste. Other properties such as particle shape, concentration, surface charge, and size distribution breadth, as well as slurry cohesiveness and adhesiveness, liquid pH and ionic strength also influence the simulant properties either directly or through other physical properties such as yield stress.