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Purification of mRNA with oligo(dT)‐functionalized magnetic particles involves a series of magnetic separations for buffer exchange and washing. Magnetic particles interact and agglomerate with each other when a magnetic field is applied, which can result in a decreased total surface area and thus a decreased yield of mRNA. In addition, agglomeration may also be caused by mRNA loading on the magnetic particles. Therefore, it is of interest how the individual steps of magnetic separation and subsequent redispersion in the buffers used affect the particle size distribution. The lysis/binding buffer is the most important buffer for the separation of mRNA from the multicomponent suspension of cell lysate. Therefore, monodisperse magnetic particles loaded with mRNA were dispersed in the lysis/binding buffer and in the reference system deionized water, and the particle size distributions were measured. A concentration‐dependent agglomeration tendency was observed in deionized water. In contrast, no significant agglomeration was detected in the lysis/binding buffer. With regard to magnetic particle recycling, the influence of different storage and drying processes on particle size distribution was investigated. Agglomeration occurred in all process alternatives. For de‐agglomeration, ultrasonic treatment was examined. It represents a suitable method for reproducible restoration of the original particle size distribution.

Accurate quantification of small microplastics in environmental and food samples is a prerequisite for studying their potential hazard. Knowledge of numbers, size distributions and polymer type for particles and fibers is particularly relevant in this respect. Raman microspectroscopy can identify particles down to 1  μ m in diameter. Here, a fully automated procedure for quantifying microplastics across the entire defined size range is presented as the core of the new software TUM-ParticleTyper 2 . This software implements the theoretical approaches of random window sampling and on-the-fly confidence interval estimation during ongoing measurements. It also includes improvements to image processing and fiber recognition (when compared to the previous software TUM-ParticleTyper for analysis of particles/fibers > 10   μ m), and a new approach to adaptive de-agglomeration . Repeated measurements of internally produced secondary reference microplastics were evaluated to assess the precision of the whole procedure.

Ongoing industrial demand for lightweight materials has spiked the research interest in aluminium-based metal matrix composites for its specific properties. The amount of scientific publication available on the matter has led to the vast production of knowledge, which highlights the need for a systematic assessment if further progress is expected. In this paper, a systematic review of the published literature is conducted, according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, on the Scopus and Web of Science databases were used in the literature search, which was completed on the 29 August 2020. The data of the research work is structured in the particle pre-processing stage and the melt processing stage. The present review clarifies the combined pair-wise effect of particles and the melt treatment performed on their wettability or dispersive or de-agglomerative capability, which allows to achieve their final mechanical properties.

The seemingly ubiquitous presence of plastic debris led to a greater focus on micro- and nanoplastics research derived from the degradation process of macroplastics. The ingestion and consequent accumulation of plastics on the biota are the main concerns. Researchers strive to make assay conditions as close as possible to those of the environment. In this regard, sonication can be applied to de-agglomerate the plastic particles, but this may alter significantly their toxicity. The aim of this study was to understand the effects of the sonication process on the acute toxicity and swimming behavior of polystyrene nanoparticles using Daphnia magna as the test organism. The results show a 2-fold reduction in the acute toxicity after the sonication process; the EC50 of the PSNP-NS was 1.28 ± 0.17 mmol while for PSNP-S the EC50 was 2.77 ± 0.32 mmol, possibly through the formation of an eco-corona on the nanoplastic surface, formed from the ions dispersed in the medium or proteins secreted by the test organisms. The mean swimming distance was reduced when compared to the control group for both the PSNP-S and PSNP-NS. This is the first research stating the toxicological differences between sonicated and non-sonicated polystyrene nanoparticle samples using Daphnia magna as test organism. Graphical abstract

The problem of preparing a ternary powder mixture, which was meant to fabricate sintered heterophase composite, and consisted of micro- and two nanosized powders, was analyzed. The microsized powder was a pure magnesium, and as nanocomponents, a silicon powder (nSi) and carbon nanotubes (CNTs) with 2% and 1% volume fractions, respectively, were applied. The powder mixtures were prepared using ultrasonic and mechanical mixing in technological fluid, and four mixing variants were applied. The morphology of the powder mixtures was characterized with scanning electron microscopy (SEM), and then, composite sinters were fabricated in a vacuum with hot temperature pressing at 580 °C under 15 MPa pressure, using a Degussa press. The reaction between the nSi and the Mg matrix, which caused the creation of the Mg2Si phase in the fabricated Mg-Mg2Si-CNT composite, was confirmed with X-ray diffraction (XRD). The porosity and hardness of the composite sinters were examined, and optical microscopy (OM) and quantitative image analyses were carried out to characterize the microstructure of the composites. In the manufacturing process of the Mg-nSi-CNT mixtures, the best results were the following: first separate de-agglomeration of nanocomponents, then their common mixing, and finally, the deposition of nanocomponents at the surface of the microsized magnesium powder. The applied procedure ensured the uniform layer formation of de-agglomerated nanocomponents on the Mg powder, without re-agglomerated nSi and CNTs. Moreover, this type of powder mixture morphology allows to obtain sinters with lower porosity and higher hardness, which is accompanied by precipitation of a finer Mg2Si phase. In the Mg-Mg2Si-CNT composite, the carbon phase was present, and it was located in the magnesium matrix and in silicide.

Pollution flashover on insulators is one of the greatest challenges affecting the smooth operation of high-voltage transmission lines. Demonstrating super-hydrophobic coatings on insulators’ interfaces is an effective measure to prevent insulator flashovers. In the present investigation, a super-hydrophobic FAS-17-modified SiO2/PDMS coating on a composite insulator was demonstrated by spraying. The coating had a contact angle of 159.2° and a sliding angle of 1.3° with better insulation properties. The prepared FAS-17-modified nano-SiO2 nanoparticles were not easy to agglomerate; to illustrate this, the binding energy was calculated by the density functional theory. The super-hydrophobic mechanism of the coating was explained in terms of the adsorption energy between SiO2 molecules and water before and after modification. This paper provides a new method to solve the pollution flashover problem of insulators and a new angle to explain the super-hydrophobic mechanism.

The objective was to investigate the effect of dry coating of salbutamol sulphate (SS) with magnesium stearate (MgSt) on the kinetics of powder de-agglomeration. The relative de-agglomeration of the MgSt coated SS powders was higher than uncoated SS at all air flow rates; the SS coated with 2 % MgSt showed the highest extent of de-agglomeration (> 5 % MgSt coated SS > 1 % MgSt coated SS). Rate of de-agglomeration was described by a cumulative de-agglomerated versus time profile. Profiles fitted a mono-exponential model and the de-agglomeration rate constant (kd) was estimated. No significant differences existed between any of the uncoated and coated powders. The significance of this study relates to the improved aerosolization and de-agglomeration performance of the MgSt coated SS powders with optimum performance of 2 % MgSt coated SS. More significant is the finding that no change existed in de-agglomeration rate constants between the coated and uncoated powders, with the potential implications that their aerosol plume concentration and deposition patterns were similar.

Purpose The purpose was to calculate distributions of powder strength of a cohesive bed to explain the de-agglomeration of lactose. Methods De-agglomeration profiles of Lactohale 300 ® (L300) and micronized lactose (ML) were constructed by particle sizing aerosolised plumes dispersed at air flow rates of 30–180 l/min. The work of cohesion distribution was determined by inverse gas chromatography. The primary particle size and tapped density distributions were determined. Powder strength distributions were calculated by Monte Carlo simulations from distributions of particle size, work of cohesion and tapped density measurements. Results The powder strength distribution of L300 was broader than that of ML. Up to 85th percentile, powder strength of L300 was lower than ML which was consistent with the better de-agglomeration of L300 at low flow rates. However, ~15% of L300 particles had higher powder strength than ML which likely to cause lower de-agglomeration for L300 at high air flow rates. Conclusion Cohesive lactose powders formed matrices of non-homogenous powder strength. De-agglomeration of cohesive powders has been shown to be related to powder strength. This study provided new insights into powder de-agglomeration by a new approach for calculating powder strength distributions to better understand complex de-agglomeration behaviour.

Detonation nanodiamonds (NDs) are a novel class of carbon-based nanomaterials, and have received a great deal of attention in biomedical applications, due to their high biocompatibility, facile surface functionalization, and commercialized synthetic fabrication. We were able to transfer the NDs from large-size agglomerate suspensions to homogenous coatings. ND suspensions have been used in various techniques to coat on commercially available substrates of pure Ti and Si. Scanning electron microscopy (SEM) imaging and nanoindentation show that the densest and strongest coating of NDs was generated when using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide (EDC/NHS)-mediated coupling to macroscopic silanized surfaces. In the next step, the feasibility of DNA-mediated coupling of NDs on macroscopic surfaces is discussed using fluorescent microscopy and additional particle size distribution, as well as zeta potential measurements. This work compares different ND coating strategies and describes the straightforward technique of grafting single-stranded DNA onto carboxylated NDs via thioester bridges.

Purpose We hypothesize that the USP induction port may de-agglomerate carrier-free powder emitting from dry powder inhalers (DPIs). Methods Aerosols emitting from a range of DPIs (Spinhaler ® , Turbuhaler ® and Osmohaler TM ) and induction ports (USP throat, straight tube, Alberta idealized mouth-throat geometry (AG)) were sized by laser diffraction. Total drug recovery was obtained by HPLC and fine particle fraction computed. Air flow patterns were simulated using Computational Fluid Dynamics (CFD). Results The straight tube did not de-agglomerate emitted powder. However, the USP throat and AG further de-agglomerated powders from the Spinhaler, but not the Turbuhaler and Osmohaler. While budesonide powder deposited similarly in all induction ports, deposition was significantly higher in the AG for both DSCG and mannitol. CFD revealed agglomerates impacting on the USP throat with higher localized velocity compared with the straight tube. CFD further showed a more complex flow pattern with high-velocity air jets in the AG, which explains the higher FPF for DSCG and the lower FPF for mannitol using the AG. Conclusion The USP throat further de-agglomerated the emitted powder from the DPI when it did not sufficiently disperse the powder. Other tools such as laser diffraction may be used for cross-examining to avoid artifacts in the results.