Spherical Particles Research Articles

Economic and Accessible Portable Homemade Magnetic Hyperthermia System: Influence of the Shape, Characteristics and Type of Nanoparticles in Its Effectiveness.

Currently, one of the main causes of death in the world is cancer; therefore, it is urgent to obtain a precocious diagnosis, as well as boost research and development of new potential treatments, which should be more efficient and much less invasive for the patient. Magnetic hyperthermia (MH) is an emerging cancer therapy using nanoparticles, which has proved to be effective when combined with chemotherapy, radiotherapy and/or surgery, or even by itself, depending on the type and location of the tumor's cells. This article presents the results obtained by using a previously developed economic homemade hyperthermia device with different types of magnetite nanoparticles, with sizes ranging between 12 ± 5 and 36 ± 11 nm and presenting different shapes (spherical and cubic particles). These magnetic nanoparticles (MNPs) were synthesized by three different methods (co-precipitation, solvothermal and hydrothermal processes), with their final form being naked, or possessing different kinds of covering layers (polyethylene glycol (PEG) or citric acid (CA)). The parameters used to characterize the heating by magnetic hyperthermia, namely the Specific Absorption Rate (SAR) and the intrinsic loss power (ILP), have been obtained by two different methods. Among other results, these experiments allowed for the determination of which synthesized MNPs showed the best performance concerning hyperthermia. From the results, it may be concluded that, as expected, the shape of MNPs is an important factor, as well as the time that the MNPs can remain suspended in solution (which is directly related to the concentration and covering layer of the MNPs). The MNPs that gave the best results in terms of the SAR were the cubic particles covered with PEG, while in terms of total heating the spherical particles covered with citric acid proved to be better.

Preparation of high-concentration coal-water slurry based on the bearing model method of spherical particles

ABSTRACT Coal-water slurry (CWS), a mixture of pulverized coal, water, and additives, is a clean liquid coal-based fuel for gasification. Superhydrophobic surface modification using a secondary particle-second liquid system is an effective CWS preparation method. In this study, the effect of the sphericity of the secondary particles on the rheological properties of CWS samples was investigated. Spherical secondary particles were found to roll in the film layer of the second liquid, resulting in a lower apparent viscosity of the CWS. The bearing model refers to the spherical secondary particle on the surface of the coal particle, similar to the balls in a bearing, which can transform sliding friction into rolling friction. The bearing model can effectively reduce frictional resistance. By modifying the coal particles with the suspension of secondary particles in the second liquid, a 73% CWS sample with good fluidity was prepared. The apparent viscosity of the 73% CWS prepared without any modification of the coal particles was 13,329.2 mPa·s, and the flow grade was C. The apparent viscosity of the 73% CWS prepared using coal particles modified with the spherical glass bead suspension was 2102.8 mPa·s, and its flow grade was A.

Pathogen identification and epidemic factor analysis of yellow catfish, Pelteobagrus fulvidraco, red lower jaw disease

Since 2020, another type of epidemic disease, ‘red lower jaw disease’ (RLJD), has broken out in yellow catfish Pelteobagrus fulvidraco every spring in China, causing large-scale deaths and significant economic losses. This new disease has the characteristics of strong infectivity, high mortality and a single host. To prevent and control RLJD, epidemiological investigation, transmission electron microscopy (TEM), virome sequencing, Koch's rule verification and epidemic factor investigation were studied in this article. The clinical symptoms of diseased yellow catfish were pale gill filaments, hyperaemia and swelling of the spleen and kidney. TEM results revealed that a large number of 35–40 nm spherical virus particles without envelope structure were found in the cytoplasm of spleen cells. The liver, spleen and kidney of the diseased fish had serious lesions. After virome sequencing, the calicivirus reads in the unique virus reads accounted for 99.5% of the unique virus reads in the diseased fish, which provided a relevant reference value for identifying the pathogen of RLJD. The full-length sequence of yellow catfish calicivirus (YCCV) obtained at 7405 bp, including the RNA-helicase domain, RdRp-1 domain and d1iqqa domain. At the same time, both PCR and TaqMan fluorescence quantitative PCR detection method of YCCV were established. Through the artificial infection test, YCCV was verified as the pathogen for RLJD. It was also found that YCCV mainly harmed the fish within 1 year, whereas the fish above 2 years had good resistance. The water temperature of the RLJD outbreak was mainly concentrated at 18 °C–24 °C. In the current study, after YCCV was verified as the pathogen of RLJD, epidemic factors including fish age and water temperature were studied, to the best of our knowledge, for the first time to provide a relevant theoretical basis for the pathogenic mechanism and prevention and control measures of yellow catfish RLJD.

Investigation of dextran-coated magnetic nanoparticles encapsulated by medication and modified with folate for targeted drug delivery: Invitro and docking studies

In this study, we synthesized dextran (DEX)-coated iron oxide (Fe3O4) and encapsulated it by the anticancer drug cisplatin (CP). This nano-composite functionalized with folic acid (FA) molecules for targeted delivery. These nanoparticles (NPs) were then used as nanocarriers for the targeted administration of CP for treating thyroid tumor cancer. The Fe3O4 NPs were synthesized using a chemical technique. The development of the Fe3O4@DEX-CP-FA nanosystem was achieved using a reverse microemulsion technique. The morphological features of the NPs were characterized using several methods, including dynamic light scattering, atomic force microscopy, vibrating sample magnetometry, high-resolution transmission electron microscopy, and field emission scanning electron microscopy. The docking study has verified that nanoparticles have anti-proliferative effects in thyroid cancer by attaching strongly to molecular targets. The MTT test evaluated the effects of a curative Fe3O4@DEX-CP-FA effect on cancerous and non-cancerous cell lines. The results obtained from the formulation of Fe3O4@DEX-CP-FA revealed the presence of spherical particles with an average size of 107.3 nm, a zeta potential of −28.7 mV, and a polydispersity value of 0.055 mV. Depending on the dose, the nanosystem exhibited cytotoxic effects on thyroid tumor (TT) and normal human thyroid (NHT) cell lines. The study findings indicate that Fe3O4@DEX-CP-FA demonstrated sustained antitumor efficacy while not revealing a harmful impact on normal cells.

Enhancing cement hydration by core/shell PS@SiO2 nanoparticles

Nanoparticles are widely used in construction. Here, nano-SiO2 is employed, in a way that prevents agglomeration of the nanoparticles, as pozzolanic material to improve Portland cement hydration and to improve the properties of the concrete. To explore the effect of nano-SiO2 and core-shell PS@SiO2 on cement properties, spherical polystyrene particles were prepared by dispersion polymerization of styrene in polar solvents and characterized by FTIR and E-SEM. The core shells PS@SiO2 were synthesized by Stöber method. The results showed an amorphous nano-SiO2 layer can be deposited uniformly on polystyrene particles. This core/shell structure was reducing the aggregation of nano-SiO2 effectively. It was shown that PS@SiO2 particles improved the concrete performances compared to blended cement with nano-SiO2 due to the agglomeration affect. Highlights • Core/shell PS@SiO2 nanoparticles with a uniform coating layer were prepared. • As-prepared nanoparticles were characterized by a variety of advanced methods. • Nanoparticles accelerate hydration and lower the spatial weight of cement paste. • Core/shell nanoparticles improve cement hydration much better than nano-SiO2.

Self-diffusiophoretic propulsion of a spheroidal particle in a shear-thinning fluid

Shear-thinning viscosity is a non-Newtonian behaviour that active particles often encounter in biological fluids such as blood and mucus. The fundamental question of how this ubiquitous non-Newtonian rheology affects the propulsion of active particles has attracted substantial interest. In particular, spherical Janus particles driven by self-diffusiophoresis, a major physico-chemical propulsion mechanism of synthetic active particles, were shown to always swim slower in a shear-thinning fluid than in a Newtonian fluid. In this work, we move beyond the spherical limit to examine the effect of particle eccentricity on self-diffusiophoretic propulsion in a shear-thinning fluid. We use a combination of asymptotic analysis and numerical simulations to show that shear-thinning rheology can enhance self-diffusiophoretic propulsion of a spheroidal particle, in stark contrast to previous findings for the spherical case. A systematic characterization of the dependence of the propulsion speed on the particle's active surface coverage has also uncovered an intriguing feature associated with the propulsion speeds of a pair of complementarily coated particles not previously reported. Symmetry arguments are presented to elucidate how this new feature emerges as a combined effect of anisotropy of the spheroidal geometry and nonlinearity in fluid rheology.

Facile construction of Bi2WO6/TiO2 microspheres heterojunction for boosting photocatalytic degradation of organic dyes

Flower-like Bi2WO6 microspheres and TiO2 spherical particles were prepared by a facile hydrothermal method without any surfactant or template. A unique Z-Scheme Bi2WO6/TiO2 heterojunction was successfully synthesized via a simple physical mixing method. The effect of mass ratio on the structure, morphology, optical properties, BET surface area and photocatalytic performance evaluated by degradation of organic dyes including Rhodamine B (RhB), methylene blue (MB) and methyl orange (MO) under solar irradiation was systemically investigated. When the mass ratio of Bi2WO6 to TiO2 was 1:4, the Bi2WO6/TiO2 composites exhibited the highest photocatalytic degradation efficiency, the highest degradation efficiency of RhB and MB reached 95.2 % and 89.3 %, which could be attributed to the construction of heterojunction structure between TiO2 and Bi2WO6. The optical absorption capacity of Bi2WO6/TiO2 composites was stronger than pure TiO2. Furthermore, the radicalquenching experiments proved that ·O2– and h+ played crucial roles in the photocatalytic reaction. The suitable band structure of Bi2WO6 and TiO2 revealed the Z-Scheme pathway and possible photocatalytic mechanism of Bi2WO6/TiO2 composites for organic dyes degradation. Thus, the direct Z-scheme Bi2WO6/TiO2 heterojunction effectively promoted separation of photogenerated electron-hole pairs, resulting in higher photocatalytic activity.

Binary Packing of Spherical Particles with Moderate Size Ratios in Viscous Fluid: A CFD-DEM Study

Binary Packing of Spherical Particles with Moderate Size Ratios in Viscous Fluid: A CFD-DEM Study

Uterine artery embolization in the treatment of uterine fibroids and the preservation of reproductive health in women 40 years of age and older: A retrospective study

Aim. To evaluate the effect of uterine artery embolization (UAE) on reproductive health in women 40 years and older. Materials and methods. A retrospective study was conducted at the perinatal center of the District Clinical Hospital of Khanty-Mansiysk. Patients were divided into two groups: the main group (group 1; n=57) included women with uterine fibroids after UAE, and the control group (group 2; n=42) included women without a history of uterine fibroids. Results. Women with uterine fibroids were statistically more likely to have grade 1 obesity (χ2=4.39; p=0.04) and less likely to have normal body weight (χ2=8.73; p=0.00) compared to women without fibroids. Smoking increased the risk of uterine fibroids twofold (χ2=4.49; p=0.03; odds ratio 1.97; confidence interval 0.64-6.11). More women with uterine fibroids had a history of abortions (n=42; 73.7%) than those without uterine fibroids (n=19; 45.2%; χ2=8.27; p=0.01). The most common gynecological comorbidities in women with uterine fibroids included inflammatory disease of the uterus (N71), endometrial polyp (N84), and endometriosis (N80); p0.05. The most common extragenital diseases in patients with uterine fibroids included thyroid disease, hypertension, and iron deficiency anemia (p0.05). Contour SE embolization agent with spherical particles was more often associated with pain (χ2=0.18; p=0.67) and less often with fever (χ2=4.47; p=0.03). There was a decrease in the number of short menstrual cycles (less than 24 days) from the moment before surgical treatment and after 24 months (χ2=34.580; p0.001) and an increase in the number of cycles of 24–38 days (χ2=14.887; p=0.005). At 24 months after UAE, there were more women with a menstrual period of less than 3 days (χ2=10.385; p=0.035) and fewer with a menstrual period of more than 8 days (χ2=34.573; p0.001). Ultrasound showed a decreased ovarian reserve at 6, 12 and 24 months after UAE (p0.05). Conclusion. When assessing the reproductive health of women 40 years and older after embolization of the uterine arteries, it was found that this method of treatment of symptomatic uterine fibroids leads to a decrease in the duration and heaviness of menstruation but increases the risk of an ovarian reserve decrease.

Effect of silica fume type on rheology and compressive strength of geopolymer mortar

Silica fume (SF) is widely used in the developing of high-performance geopolymer systems. Previous studies have shown that using different types of SF may have different influences on the performance of geopolymers. What are the key factors (affecting the properties of geopolymers) still need to be clarified? This paper investigated the effects of three types of silica fume (SF1− SF3) with various silica contents (98.0%, 94.7% and 53.1%) and particle sizes (D50: 3.3 μm, 3.1 μm and 11.8 μm) on the rheology and compressive strength of alkali-activated calcium alumina cement (CAC)/fly ash mortar. The incorporation of SF can significantly increase the plastic viscosity. The increase in plastic viscosity was due to the ball-bearing action of the spherical SF particles, which reduced the friction between the particles under shearing. Replacing 20% of the fly ash with SF1 and SF2 improved the compressive strength of geopolymer mortars while the incorporation of SF3 decreased the compressive strength at the same replacement ratio. Inductively coupled plasma (ICP) spectrometry results indicated that the amorphous silica in the SFs was dissolved in an alkali solution. Activators with high concentrations of monomer and dimmer silicon groups may promote the reaction between precursors and activators. The formation of additional aluminosilicate gels reduced the amount of large capillary pores (500 nm to 1000 nm), leading to improved strength. The incorporation of coarse SF3 introduced extra voids in the mixture, as suggested by calculations of packing density, leading to reduced strength.

Molecular Dynamics Simulation on Solidification Microstructure and Tensile Properties of Cu/SiC Composites.

The shape of ceramic particles is one of the factors affecting the properties of metal matrix composites. Exploring the mechanism of ceramic particles affecting the cooling mechanical behavior and microstructure of composites provides a simulation basis for the design of high-performance composites. In this study, molecular dynamics methods are used for investigating the microstructure evolution mechanism in Cu/SiC composites containing SiC particles of different shapes during the rapid solidification process and evaluating the mechanical properties after cooling. The results show that the spherical SiC composites demonstrate the highest degree of local ordering after cooling. The more ordered the formation is of face-centered-cubic and hexagonal-close-packed structures, the better the crystallization is of the final composite and the less the number of stacking faults. Finally, the results of uniaxial tensile in three different directions after solidification showed that the composite containing spherical SiC particles demonstrated the best mechanical properties. The findings of this study provide a reference for understanding the preparation of Cu/SiC composites with different shapes of SiC particles as well as their microstructure and mechanical properties and provide a new idea for the experimental and theoretical research of Cu/SiC metal matrix composites.

Comparison of Newtonian and glycerol-water solution-based SiO2 nanofluid droplets impacting on heated spherical surfaces

The dynamic interactions of liquid droplets with heated spherical particles, relevant across various scientific and engineering disciplines, display intriguing collision behaviors whose principles are yet to be fully deciphered. This investigation utilizes high-speed photography to explore the wetting and non-wetting responses of different Newtonian and glycerol-water solution-based SiO2 nanofluid droplets upon contact with heated particles. Findings indicate that nanofluid droplets disrupt the thermal field and modify the surface morphology of particles more extensively under wetting than non-wetting conditions. Wetting conditions lead to significant alterations in the liquid film thickness and notable velocity field disruptions for droplets of deionized water and glycerol solution. Conversely, in the non-wetting phase, droplets nearing full rebound cause less disturbance to the velocity field, a behavior consistent across all fluid types and particle temperatures. The shape changes nanofluid droplets undergo when rebounding and separating from the particle surface are similar to those seen in glycerol solution and water droplets. Droplets in the breakup-rebound phase experience shorter contact times than those merely rebounding. A phase diagram is presented, detailing wetting (receding-deposition and boiling-breakup) and non-wetting (rebound and breakup-rebound) actions. An increase in the Weber number necessitates a higher particle temperature for the transition from rebound to breakup-rebound, which corroborates with theoretical insights. Furthermore, droplets achieve their maximum spreading area during the boiling-breakup mode.

Morphological studies, photocatalytic degradation of organic dyes and anticancer potential of copper sulfide nanoparticles prepared from bis(diallyl dithiocarbamato)copper(II) complex

Bis(diallyl dithiocarbamato)copper(II) complex was synthesized and characterized by single crystal X-ray crystallography. The molecular structure revealed dimeric copper(II) complex consisting of two copper(II) ions that coordinate two molecules of diallydithiocarbamato anions in bidentate chelating modes and the centrosymmetrically related diallydithiocarbamato anions bridges the S-atom of the adjacent chelating ligand to formed square pyramidal geometry around the copper(II) ions. Copper sulfide nanoparticles were prepared at 160 °C by thermolysis of the copper(II) complex in dodecylamine (DDA), hexadecylamine (HDA), and octadecylamine (ODA) to study the effect of capping agents on the structural morphologies, photocatalytic properties, and anticancer potential of the as-prepared copper sulfides nanoparticles. Powder X-ray diffraction patterns confirmed Cu9S5 digenite crystalline phases for CuS-DDA and CuS-HDA while CuS-ODA is covellite crystalline phase. HRTEM images showed spherical particles with particle sizes in the range 2–25 nm. The copper sulfide nanophotocatalysts are efficient for the degradation of bromophenol blue with the highest photocatalytic efficiency of 95.14 % for CuS-DDA followed by CuS-HDA with 94.52 % and 93.95 % for CuS-ODA. The anticancer potentials of the compounds showed that CuS-HDA is the most potent with IC50 values of 1.22 µg/mL against HEK293 and 28.78 µg/mL against HeLa.

The effect of the number of sulfonic acids in polysiloxanes as fillers for polymer electrolyte membranes in energy storage applications

A series of sulfonic acid-functionalized polysiloxanes (MASFPs) that can be used to reduce the cost and improve the properties of proton exchange membranes (PEMs) by acting as fillers have been synthesized. In this paper, we describe the synthesis of MASFPs with varying numbers of sulfonic acid groups with the aid of mercaptoethanol. An array of analytical techniques were employed to characterize the synthesized MASFPs. The broad peak observed in the X-ray diffraction pattern of MASFPs between 2θ = 15–25° signifies their amorphous characteristics. Analyses by infrared spectroscopy also identify MASFPs that contain stretching vibrations for –SO3H, –CH2, and Si–O– group. The thermogravimetric analysis demonstrates the thermal stability of these MASFPs. The surface morphology analysis of the MASFPs using FESEM and HRTEM revealed the presence of spherical particles that exhibited significant aggregation and distortion. By employing X-ray photoelectron spectroscopy (XPS) to determine the atomic weight percentage of sulfur present in the MASFPs, the number of sulfonic acids contained within was verified. The sulfur content of MASFPs is determined by XPS to be as follows: MASFP-4 > MASFP-3 > MASFP-2 > MASFP-1. The presence of Q4, Q3, T3, and T2 signals, as determined by 29Si MAS NMR analysis, confirms the polysiloxane formation. Preliminary studies of the composite membrane prepared using the MASFPs with perfluorosulfonic acid (PFSA:MASFP in 75:25 ratio) exhibited superior ionic conductivity (0.102 S/cm) and ion-exchange capacity (1.16 meq/g) in comparison to the commercial Nafion membrane. Overall, using a mercaptoethanol-assisted process to synthesize sulfonic acid functionalized polysiloxanes is an excellent way to increase the incorporation of sulfonic acids and it can be applied to the synthesis of various other inorganic nanofillers.

The effect of doping sulphhydryl-functionalised silica with different diameters on the electro-optical properties of PDLC

ABSTRACT In this study, we synthesised two kinds of spherical SiO2-SH particles with uniform and non-uniform morphologies, and investigated their effects on the electro-optical properties of PDLC. Compared with uniform SiO2-SH nanoparticles, we found that the samples doped with non-uniform SiO2-SH regulate the electro-optical properties of PDLC better. The electro-optical properties test results demonstrated that doping a small amount of SiO2-SH with different sizes significantly reduced the driving voltage of PDLC and maintained a high contrast ratio. SEM results indicated that the size of the polymer meshes was broadened with increasing SiO2-SH doping. This phenomenon can be attributed to the larger specific surface area and higher concentration of sulphhydryl groups in SiO2-SH particles of different sizes. These characteristics enable SiO2-SH to better react with acrylate monomers, thereby improving modulation effects on the electro-optical properties of PDLC. However, when the doping amount exceeded a certain value, the driving voltage of PDLC began to rise, and its electro-optical properties deteriorated because of the agglomeration of nanoparticles at higher doping levels. This study demonstrated that doping SiO2-SH particles of different sizes can optimise the properties of PDLC, which provided new ideas and directions for doping PDLC with nanomaterials.

Graphite sheet-supported bimetallic RhNi thin film alloys for enhanced and durable hydrogen evolution in acidic environments

Noble metal-based materials are excellent catalysts for hydrogen production from water electrolysis, but their high cost and limited availability hinder widespread use. However, precious metals can be effectively utilized in catalysts by forming alloys with low-cost 3d transition metals, thereby reducing the need for precious metals, while enhancing the performance. In this study, aerosol-assisted chemical vapor deposition was employed to deposit bimetallic rhodium-nickel (RhNi) alloy thin films on a graphite sheet for hydrogen evolution reaction (HER) catalysis in a 0.5 M H2SO4 solution. Thin-film morphological patterns were significantly changed as the deposition time varied from 45 to 135 min. The RhNi alloy fabricated for 90 min outperformed its counterparts, displaying lower overpotential of 40 and 197 mV at 10 and 1000 mA cm−2, small Tafel kinetics (54 mV dec−1), high conductivity (0.57 Ω) and large electrochemical surface area (3312 cm2), and extended stability (48 h) compared to pure Rh metal and other reported catalysts. The superior HER performance arises from the synergistic effects between Rh and Ni metals, coupled with a uniform layer of spherical particles that enhance conductive properties and reaction rates by providing maximized active sites on graphite surface. This work provides valuable guidelines for efficiently preparing highly active and durable thin-film electrocatalyst within short time span and applying directly in fuel cell for hydrogen production.

Flexible Janus Black Silicon Photothermal Conversion Membranes for Highly Efficient Solar-Driven Interfacial Water Purification.

Photothermal conversion materials are critical in the development of solar-driven interfacial evaporation techniques; however, achieving a high energy conversion efficiency remains challenging owing to the high cost and instability of light-absorbing materials, in addition to the difficulties of simultaneously improving light absorption while suppressing heat loss. A black silicon (Si) powder with a porous structure was prepared by chemical etching of a low-cost commercial micron-sized Al-Si alloy, and a flexible Janus black Si photothermal conversion membrane was constructed. The partially broken spherical particles and porous structure obtained after etching enhanced the refraction of light from the Si powder, imparting the prepared membrane with an average light absorption rate of 95.95% over the solar spectrum. Evaporation from the membrane increased the intermediate water content and reduced the equivalent evaporation enthalpy. The thermal conduction loss was inhibited through a one-dimensional water transport structure, and the membrane achieved a water evaporation rate of 2.17 kg m-2 h-1 and a photothermal efficiency of 94.95% under 1 sun illumination. Benefiting from the broadband absorption and high photothermal efficiency of black Si powder, surface modification of hydrophobic polydimethylsiloxane, and directional salt-out structure design, the evaporation rate of the Janus black Si membrane-based system in a 10% NaCl solution was maintained >2.10 kg m-2 h-1 after 7 days of continuous evaporation cycles. The removal rate of metal ions from simulated seawater and from practical wastewater containing complex heavy metals reached >99.9%, indicating the promising potential of black Si membrane for application in solar-driven interfacial water purification.

Spray-dried ternary bioactive glass microspheres: Direct and indirect structural effects of copper-doping on acellular degradation behavior

Silicate-based bioactive glass nano/microspheres hold significant promise for bone substitution by facilitating osteointegration through the release of biologically active ions and the formation of a biomimetic apatite layer. Cu-doping enhances properties such as pro-angiogenic and antibacterial behavior. While sol-gel methods usually yield homogeneous spherical particles for pure silica or binary glasses, synthesizing poorly aggregated Cu-doped ternary glass nano/microparticles without a secondary CuO crystalline phase remains challenging. This article introduces an alternative method for fabricating Cu-doped ternary microparticles using sol-gel chemistry combined with spray-drying. The resulting microspheres exhibit well-defined, poorly aggregated particles with spherical shapes and diameters of a few microns. Copper primarily integrates into the microspheres as Cu0 nanoparticles and as Cu2+ within the amorphous network. This doping affects silica network connectivity, as calcium and phosphorus are preferentially distributed in the glass network (respectively as network modifiers and formers) or involved in amorphous calcium phosphate nano-domains depending on the doping rate. These differences affect the interaction with simulated body fluid. Network depolymerization, ion release (SiO44−, Ca2+, PO43−, Cu2+), and apatite nanocrystal layer formation are impacted, as well as copper release. The latter is mainly provided by the copper involved in the silica network and not from metal nanoparticles, most of which remain in the microspheres after interaction. This understanding holds promising implications for potential therapeutic applications, offering possibilities for both short-term and long-term delivery of a tunable copper dose. Statement of significanceA novel methodology, scalable to industrial levels, enables the synthesis of copper-doped ternary bioactive glass microparticles by combining spray-drying and sol-gel chemistry. It provides precise control over the copper percentage in microspheres. This study explores the influence of synthesis conditions on the copper environment, notably Cu0 and Cu2+ ratios, characterized by EPR spectroscopy, an aspect poorly described for copper-doped bioactive glass. Additionally, copper indirectly affects silica network connectivity and calcium/phosphorus distribution, as revealed by SSNMR. Multiscale characterization illustrates how these features impact acellular degradation in simulated body fluid, highlighting the therapeutic potential for customizable copper dosing to address short- and long-term needs.

Calculating the acoustic radiation force on spherical particles in a standing ultrasound wave field considering single and multiple scattering

Ultrasound directed self-assembly (DSA) utilizes the acoustic radiation force (ARF) associated with a standing ultrasound wave to organize particles dispersed in a fluid medium into specific patterns. The ARF is a superposition of the primary acoustic radiation force, which results from the incident standing ultrasound wave, and the acoustic interaction force, which originates from single and multiple scattering between neighboring particles. In contrast with most reports in the literature that neglect multiple scattering when calculating the ARF, we demonstrate that the deviation between considering single or multiple scattering may reach up to 100%, depending on the ultrasound DSA process parameters and material properties. We evaluate a theoretical case with three spherical particles in a viscous medium and derive operating maps that quantify the deviation between both scattering approaches as a function of the ultrasound DSA process parameters. Then, we study a realistic system with hundreds of particles dispersed in a viscous medium, and show that the deviation between the ARF resulting from single and multiple scattering increases with decreasing particle size and increasing medium viscosity, density ratio, compressibility ratio, and particle volume fraction. This work provides a quantitative basis for determining whether to consider single or multiple scattering in ultrasound DSA simulations.

Experimental investigation on shape segregation of 3D printed particles using an Freeman FT4 rheometer

This study examines how granular mixtures of differently shaped particles segregate in a Freeman (FT4) rheometer apparatus. The mixtures contained two sets of particles with varying shapes and relative sizes. While our focus was on the effect of particle shape on segregation, we recognized that even slight differences in size could lead to segregation. We specifically investigated when particles of different shapes have the same effective size, exploring three cases: 1) the largest sphere within a cubic particle (inscribed sphere), 2) the smallest sphere enclosing a cubic particle (circumscribed sphere), and 3) a sphere and cube with equal volume. Our key finding indicates that binary mixtures of cubical and spherical particles can significantly segregate either axially or radially in the particle bed with a circumscribed sphere configuration. We propose that the primary mechanism for this is percolation and additionally, in the case of radial segregation, ordering of cubes adjacent to the cylinder wall.