Bead Size Research Articles

Fe-doped Co3O4 nanostructures prepared via hard-template method and used for the oxygen evolution reaction in alkaline media

Low-cost and highly efficient anode catalysts are required for the oxygen evolution reaction (OER), which is integral to the commercialization of alkaline-based water electrolysis. Herein, pore size-controlled Fe-doped Co3O4 nanostructures are prepared as non-precious metal anode catalysts using a hard-template method with silica beads of different sizes, ranging from 20 to 1000 nm in diameter. The pore size distribution and specific surface area of the catalysts are measured by nitrogen adsorption/desorption analysis and mercury intrusion porosimetry. The electrochemical properties and OER performances of the catalysts are evaluated in half and unit cells, respectively. Among the catalysts studied, FCO-T-500 synthesized using 500 nm-sized silica beads exhibits the best OER activity and stability, given by a high current density of 847 mA cm−2 at 1.8 V and superior 100 h-stability during single cell test of anion exchange membrane water electrolysis. The improved OER performance of FCO-T-500 can be attributed to the optimal pore size favorable for gas diffusion and mass transport, sufficient surface OH and H2O groups produced via KOH leaching, the largest number of electrocatalytic active sites, and the fastest charge-transfer reaction.

Microencapsulation of parathyroid cells via electric field and non-surgical transplantation approach.

Hypoparathyroidism is a rare disease with low PTH, mostly seen as a consequence of neck surgery. Current management is the prescription of calcium and vitamin D, but the definitive treatment is parathyroid allotransplantation, which frequently triggers an immune response, thus cannot achieve the expected success. To overcome this problem, encapsulation of allogeneic cells is the most promising method. By optimizing the standard alginate cell encapsulation technique with parathyroid cells under high-voltage application, the authors reduced the size of parathyroid-encapsulated beads and evaluated these samples in vitro and in vivo. Parathyroid cells were isolated, and standard-sized alginate macrobeads were prepared without any electrical field application, while microbeads in smaller sizes (< 500µm), by the application of 13kV. Bead morphologies, cell viability, and PTH secretion were evaluated in vitro for four weeks. For the in vivo part, beads were transplanted into Sprague-Dawley rats, and after retrieval, immunohistochemistry and PTH release were evaluated in addition to the assessment of cytokine/chemokine levels. The viability of parathyroidcells in micro- and macrobeads did not differ significantly. However, the amount of in vitro PTH secretion from microencapsulated cells was significantly lower than that from macroencapsulated cells, although it increased throughout the incubation period. Immunohistochemistry of PTH staining in both of the encapsulated cells identified as positive after retrieval. Contrary to the literature, a minimal in vivo immune response was developed for alginate-encapsulated parathyroid cells, regardless of bead size. Our findings suggest that injectable, micro-sized beads obtained using high-voltage may be a promising method for a non-surgical transplantation approach.

Development of an Artificial Intelligence-Based System for Predicting Weld Bead Geometry

The prediction of the weld bead geometry parameters is an important aspect of welding processes due to it is related to the strength of the welded joint. This research focuses on using statistical design techniques and a deep learning neural network to predict the weld bead shape parameters of shielded metal arc welding (SMAW), metal inert gas (MIG), and tungsten inert gas (TIG) welding processes. With the statistical design techniques, experiments were carried out to obtain the data for generating the regression models. Establishing mathematical models that shows the relationship between welding process parameters and weld bead size is significant for practical applications. The mathematical model enables the determination of the weld bead size when setting specific welding process parameters. In this research, experimental research results were obtained to build mathematical models showing the relationship between welding process parameters and weld bead geometries for SMAW, MIG, and TIG welding processes. The research results serve as the basis for establishing predictive systems or optimizing welding process parameters. With deep learning neural network techniques, we developed an artificial intelligence-based system for predicting complicated relations between the welding process parameters and the weld bead size. Both a regression model and the deep learning model result in a good correlation between the welding process parameters and the weld bead geometry.

Development of Novel pH-Sensitive Eudragit Coated Beads Containing Curcumin-Mesalamine Combination for Colon-Specific Drug Delivery.

This research aims to develop a drug delivery system that effectively treats colitis while administering curcumin/mesalamine by coating alginate/chitosan beads with Eudragit® S-100 to target the colon. Beads were tested to determine their physicochemical characteristics. Coating with Eudragit® S-100 prevents drug release at a pH of less than 7; this was demonstrated by in-vitro release conducted in a medium with gradually varying pH to mimic circumstances in various regions of the gastrointestinal tract. This study examined the efficacy of the coated beads in treating acetic acid-induced colitis in rats. Results showed that spherical beads were formed with an average diameter of 1.6-2.8 mm, and the obtained swelling ranged from 409.80% to 890.19%. The calculated entrapment efficiency ranged from 87.49% to 97.89%. The optimized formula F13 (which was composed of mesalamine-curcumin active ingredients, Sodium alginate as a gelling agent, chitosan as a controlled release agent, CaCl2 as a crosslinking agent, and Eudragit S-100 as a pH-sensitive coating agent) demonstrated the best entrapment efficiency (97.89% ± 1.66), swelling (890.19% ± 60.1), and bead size (2.7 ± 0.62 mm). In formulation #13, which was coated with Eudragit S 100, curcumin (6.01 ± 0.04%) and mesalamine (8.64 ± 0.7%), were released after 2 h at pH 1.2; 6.36 ± 0.11% and 10.45 ± 1.52% of curcumin and mesalamine, respectively, were then released after 4 h and at pH 6.8. Meanwhile, at pH 7.4, after 24 h, approximately 85.34 ± 2.3% (curcumin) and 91.5 ± 1.2% (mesalamine) were released. Formula #13 significantly reduced the colitis, and this suggests that the developed hydrogel beads can be used for delivering curcumin-mesalamine combinations to treat ulcerative colitis after adequate research.

Amorphous Cellulose: Graphene Oxide Composite Bead

In this research, we developed an efficient method for the fabrication of amorphous cellulose-graphene oxide composite. Amorphous cellulose (AC) and amorphous cellulose-graphene oxide (ACGO) beads were fabricated via H2SO4 gelatinization using eucalyptus paper as a raw material. The cellulose gel was droplet-extruded into deionized (DI) water and transformed to a solid bead via the water-regeneration process. Small AC and ACGO quasi-sphere beads with diameter of 2 mm were obtained. The semicrystalline eucalyptus cellulose was transformed into amorphous cellulose after the regeneration process. The entrapment of graphene oxide (GO) by the amorphous cellulose was confirmed by scanning electron microscopy (SEM), fourier-transform infrared (FTIR) and raman spectroscopies (Raman). The gelatinization and regeneration processes offered a simple and efficient methodology for AC and ACGO bead fabrication. HIGHLIGHTS Amorphous cellulose (AC) and amorphous cellulose-graphene oxide (ACGO) beads were successfully fabricated via sulfuric acid gelatinization The average sizes of AC and ACGO beads were 2.11±13 and 2.14 ± 0.12 mm, respectively Structural characterization confirmed the transformation of cellulose I to cellulose II and graphene oxide was successfully embedded in ACGO beads The added graphene oxide interacted with the amorphous cellulose and made the surface of ACGO beads smooth GRAPHICAL ABSTRACT

Reinforcement learning and optimization based path planning for thin-walled structures in wire arc additive manufacturing

A well-designed deposition path is one of the basic prerequisites for the successful fabrication of a component by deposition based additive manufacturing processes. Three main approaches are currently used to determine the deposition path. First, these are general path templates that are applied to the entire geometry. Nevertheless, this approach suffers from poor adaptability to the geometry. Second, they are algorithms where it is necessary to divide the geometry into sub-parts, which are then filled either by general path templates or by paths derived, e.g., from the signed distance function. These often require human intervention and may fail to find a suitable deposition path. Third, there are planning strategies that deal only with a particular topologies, and are not transferable to other geometries. A developed path planning framework named RLPlanner, which makes use of reinforcement learning as well as automatized prepossessing and Sequential Least Squares Programming optimization method, addresses these drawbacks. This solution enables fully automatic deposition path planning for thin-walled structures in wire arc additive manufacturing. In addition, the framework is able to vary the welding speed with the wire feed rate and thus influence the size of the weld bead leading to better adaptability to the geometry.

Parameters affecting calcium-alginate bead characteristics: Viscosity of hydrocolloids and water solubility of core material

In this study, calcium-alginate beads were produced and characterized by ionic gelation technique using three different copolymers (gum arabic (GA), κ-carrageenan (CG), guar gum (GG)), and seven different phenolic compounds (tannic acid, chlorogenic acid, gallic acid, p-coumaric acid, caffeic acid, naringin, and hesperidin). The effect of the viscosity of copolymer and water solubility of the phenolic compound on the size, shape, swelling, encapsulation efficiency (EE), loading capacity (LC), and production yield (PY) of the beads were investigated. In addition, the impact of the core material concentration in the calcium chloride solution on the EE was determined. The bead sizes increased by 6.8, 11.4, and 35.3 %, respectively, with the use of GA, CG, and GG. The EE of the beads ranged from 28.36 to 89.30 % and increased with increasing copolymer viscosity and decreasing water solubility of the phenolic compound. When the core material concentration difference between the alginate and calcium chloride solutions was reduced to zero, the EE of the gallic acid bead increased from 32.95 % to 89.05 %. The results of this study show that copolymer viscosity, the water solubility of core material, and the core material concentration difference between alginate and calcium solutions should be considered in ionic gelation applications.

Bead size has a greater effect on in vitro elution from antimicrobial-impregnated calcium sulfate beads than drug concentration

To compare the elution characteristics of amikacin-impregnated calcium sulfate (CaSO4) beads based on different drug concentrations and bead size configurations. Six groups of amikacin-impregnated CaSO4 beads and one negative control group. Amikacin-impregnated CaSO4 beads were formed with either 500 mg (low-concentration) or 1 g (high-concentration) of amikacin per 15 g CaSO4 hemihydrate powder. The number of beads necessary to approximate 150 mg of amikacin for each of the 3 bead sizes (3 mm, 5 mm, and 7 mm) at both low and high concentrations were placed in 6 mL of phosphate-buffered saline. The saline was sampled at 14 time points over 28 days. Amikacin concentrations were determined using liquid chromatography-mass spectrometry. Smaller beads reached higher mean peak concentrations than larger beads (P < .0006). Peak concentrations for the low- and high-concentration groups were 20.5 mg/mL and 27.4 mg/mL, 13.1 mg/mL and 14.0 mg/mL, and 8.85 mg/mL and 6.75 mg/mL for the 3 mm, 5 mm, and 7 mm beads, respectively. Bead size also affected the length of therapeutic duration, lasting 6 days for the 3 mm and 5 mm beads and 9 days for the 7 mm beads. However, this was only statistically evident among the high-concentration beads (P < .044). Antimicrobial concentration within the same bead sizes did not affect elution. Amikacin-impregnated CaSO4 beads achieved extreme supratherapeutic eluent concentrations. While additional studies are needed, bead size significantly affected elution with smaller beads reaching higher peak concentrations and 7 mm, high-concentration beads demonstrating a longer therapeutic duration than smaller beads.

Characterization of Bubble Transport in Porous Media Using a Microfluidic Channel

This study investigates the effect on varying flow rates and bubble sizes on gas–liquid flow through porous media in a horizontal microchannel. A simple bubble generation system was set up to generate bubbles with controllable sizes and frequencies, which directly flowed into microfluidic channels packed with different sizes of glass beads. Bubble flow was visualized using a high-speed camera and analyzed to obtain the change in liquid holdup. Pressure data were measured for estimation of hydraulic conductivity. The bubble displacement pattern in the porous media was viscous fingering based on capillary numbers and visual observation. Larger bubbles resulted in lower normalized frequency of the bubble breakthrough by 20 to 60 percent. Increasing the flow rate increased the change in apparent liquid holdup during bubble breakthrough. Larger bubbles and lower flow rate reduced the relative permeability of each channel by 50 to 57 percent and 30 to 64 percent, respectively.

Removal of powders from cavities in contaminated surfaces by shock and plasma generated by an adjacent electro-static discharge

An electrostatic discharge (ESD) produced between pin electrodes above a cavity filled with powder is explored as means of contactless removal of particles from contaminated surfaces. The ESD is produced by discharging a capacitor through an air gap. Glass beads of different sizes serve as model powders filling cavities of different depths. Masses of both loaded and ejected powders are measured. The motion of the ejected particles is studied using high-speed video. Most of the ejected particles move vertically up with the initial velocities varied from ca. 4 to 11 m/s. Changing the mechanical properties of the substrate holding the powder does not significantly affect the velocities of the ejected particles. For powders removed from cavities as a result of interaction with the shock and plasma produced by ESD, the number of particle layers ejected is determined by the particle size and the ESD energy, but is not significantly affected by the cavity depth. A single ESD pulse can be effective in the complete removal of powder particles from relatively shallow, 0.2-mm deep cavity. Estimates suggest that the particles are primarily ejected due to the lift forces produced by local velocity gradients of the gas above the loaded powder layer.

Production and characterization of Ziziphus jujuba extract-loaded composite whey protein and pea protein beads based on sodium alginate-IFPG (insoluble fraction of Persian gum).

This research was aimed at the fabrication of jujube extract (JE)-loaded beads by extrusion, using whey protein isolate (WPI), chickpea protein concentrate (PPC) and a combination of two types of hydrocolloid insoluble fraction of Persian gum (IFPG) and sodium alginate (Al). JE-loaded beads with the highest encapsulation efficiency (10.87%) and polyphenol content (120.8 mg L-1 gallic acid) were obtained using Al-IFPG/PPC at 4 °C. The Al-IFPG, Al-IFPG/WPI and Al-IFPG/PPC beads revealed 5.66, 6.85 and 5.76 mm bead size, respectively, and almost all of them demonstrated a homogeneous and spherical structure. Fourier transform infrared spectroscopy data proved that the stable structure of the Al-IFPG beads was due to hydrogen bonding and electrostatic interactions. The thermostability of beads loaded with JE based on Al-IFPG/WPI was significantly enhanced compared to pure Al-IFPG. Texture evaluation of JE-loaded beads based on Al-IFPG incorporation with WPI revealed an increment in the hardness of beads. This study confirmed the potential of Al-IFPG complex beads for the effective delivery of jujube extract via incorporation into pea and whey proteins and for the expansion of its use in products. © 2023 Society of Chemical Industry.

Readily Accessible High-Throughput Experimentation: A General Protocol for the Preparation of ChemBeads and EnzyBeads.

Chemical- and enzyme-coated beads (ChemBeads and EnzyBeads) were introduced recently as a universal strategy for the accurate dispensing of various solids in submilligram quantities using automated instrumentation or manual dispensing. The coated beads are prepared using a resonant acoustic mixer (RAM)-an instrument that may be available only to well-established facilities. In this study, we evaluated alternative coating methods for preparing ChemBeads and EnzyBeads without the use of a RAM. We also evaluated the effects of bead sizes on loading accuracy using 4 coating methods and 12 solids (9 chemicals and 3 enzymes) as test subjects. While our original RAM coating method is the most versatile for the broadest range of solids, high-quality ChemBeads and EnzyBeads that are suitable for high-throughput experimentation can be prepared using alternative methods. These results should make ChemBeads and EnzyBeads readily accessible as the core technology for setting up high-throughput experimentation platforms.

Alterations in Abundance and Compartmentalization of miRNAs in Blood Plasma Extracellular Vesicles and Extracellular Condensates during HIV/SIV Infection and Its Modulation by Antiretroviral Therapy (ART) and Delta-9-Tetrahydrocannabinol (Δ9-THC).

Alterations in Abundance and Compartmentalization of miRNAs in Blood Plasma Extracellular Vesicles and Extracellular Condensates during HIV/SIV Infection and Its Modulation by Antiretroviral Therapy (ART) and Delta-9-Tetrahydrocannabinol (Δ9-THC).

SIV Infection Regulates Compartmentalization of Circulating Blood Plasma miRNAs within Extracellular Vesicles (EVs) and Extracellular Condensates (ECs) and Decreases EV-Associated miRNA-128.

SIV Infection Regulates Compartmentalization of Circulating Blood Plasma miRNAs within Extracellular Vesicles (EVs) and Extracellular Condensates (ECs) and Decreases EV-Associated miRNA-128.

Facile Process for Fabrication of Silicon Micro-Nanostructures of Different Shapes as Molds for Fabricating Flexible Micro-Nanostructures and Wearable Sensors.

We report a method to fabricate silicon micro-nanostructures of different shapes by tuning the number of layers and the sizes of self-assembled polystyrene beads, which serve as the mask, and by tuning the reactive ion etching (RIE) time. This process is simple, scalable, and inexpensive without using any sophisticated nanomanufacturing equipment. Specifically, in this work, we demonstrate the proposed process by fabricating silicon micro- or nanoflowers, micro- or nanobells, nanopyramids, and nanotriangles using a self-assembled monolayer or bilayer of polystyrene beads as the mask. We also fabricate flexible micro-nanostructures by using silicon molds with micro-nanostructures. Finally, we demonstrate the fabrication of bandage-type electrochemical sensors with micro-nanostructured working electrodes for detecting dopamine, a neurotransmitter related to stress and neurodegenerative diseases in artificial sweat. All these demonstrations indicate that the proposed process provides a low-cost, easy-to-use approach for fabricating silicon micro-nanostructures and flexible micro-nanostructures, thus paving a way for developing wearable micro-nanostructures enabled sensors for a variety of applications in an efficient manner.

Experimental investigations and parametric effects on depositions of super duplex stainless steel in wire arc additive manufacturing

Identification of suitable processing conditions is essential for successful fabrication of engineering components of any material by wire arc additive manufacturing (WAAM). Objectives of this article are to determine optimal process parameters for deposition of super duplex stainless steel (SDSS) ER2594 in gas metal arc welding (GMAW)-based WAAM using response surface methodology (RSM) and characterisation of the deposited materials. The developed RSM-based models of deposition geometry in terms of bead width and bead height, and deposition rate based on experimental data showed higher values of width, height and deposition rate for increasing voltage and wire feed speed due to higher heat input onto the tip of wire and decreasing torch travel speed and gas flow rate. Results of tensile tests of the deposited SDSS exhibited increase of mechanical properties like yield strength, ultimate tensile strength and elongation by 28.8%, 14.3% and 84%, respectively, compared to that of the cast SDSS material. Microstructural characterisations of the deposited SDSS wall using SEM exhibited a typically higher ratio of austenite to ferrite phases (77:23) with oriented columnar dendritic structure compared to that of the base material (50:50). Pre-heating of the substrate could enhance the deposited bead size with higher width due to higher energy available for melting and spreading of the beads.

Hoverfly (Eristalis tenax) pursuit of artificial targets.

The ability to visualize small moving objects is vital for the survival of many animals, as these could represent predators or prey. For example, predatory insects, including dragonflies, robber flies and killer flies, perform elegant, high-speed pursuits of both biological and artificial targets. Many non-predatory insects, including male hoverflies and blowflies, also pursue targets during territorial or courtship interactions. To date, most hoverfly pursuits have been studied outdoors. To investigate hoverfly (Eristalis tenax) pursuits under more controlled settings, we constructed an indoor arena that was large enough to encourage naturalistic behavior. We presented artificial beads of different sizes, moving at different speeds, and filmed pursuits with two cameras, allowing subsequent 3D reconstruction of the hoverfly and bead position as a function of time. We show that male E. tenax hoverflies are unlikely to use strict heuristic rules based on angular size or speed to determine when to start pursuit, at least in our indoor setting. We found that hoverflies pursued faster beads when the trajectory involved flying downwards towards the bead. Furthermore, we show that target pursuit behavior can be broken down into two stages. In the first stage, the hoverfly attempts to rapidly decreases the distance to the target by intercepting it at high speed. During the second stage, the hoverfly's forward speed is correlated with the speed of the bead, so that the hoverfly remains close, but without catching it. This may be similar to dragonfly shadowing behavior, previously coined 'motion camouflage'.

Effects of lead and lean in multi-axis directed energy deposition

The present study examines the effect of varying laser incidence angles on textural, microstructural, and geometric characteristics of directed energy deposition (DED) processed materials, providing a more comprehensive outlook on participating laser-matter interaction phenomena and ultimately devising strategies to ameliorate print performance. In this study, single-layer, single-/multi-track specimens were processed to examine the effect of non-orthogonal angular configurations on bead morphology, microstructure, phase composition, and textural representation of DED-processed 316L stainless steel materials. It was observed that bead size decreased at increasing lead and lean angles. Asymmetry in the distribution of the bead morphology as a function of lead angle indicates better catchment for acute lead angle configurations over obtuse configurations. No significant differences in phase composition, texture, and microstructure were observed in moderate off-axis configurations. When the penetration depth for the deposits was below 20 μm, columnar structures dominated the microstructure of the deposited material. At deeper penetration depths, columnar and equiaxed structures were observed at the bead-substrate interface and center of the bead, respectively. Compared to powder-blown DED, wire-DED dilution profiles were found to be asymmetric in both orthogonal and non-orthogonal wire DED samples.

Particle Size Tailoring of Quercetin Nanosuspensions by Wet Media Milling Technique: A Study on Processing and Formulation Parameters.

A large number of new substances have insufficient biopharmaceutical properties for oral administration caused by their slow dissolution rate and poor solubility. The purpose of our experiment was to improve the physicochemical properties of a hydrophobic drug, quercetin, by the nanomilling approach. Quercetin nanosuspensions were prepared using a wet-milling method followed by lyophilization. Stabilizer type and ratio, drug content, milling time, and bead size were identified as critical variables, and their impacts on quercetin particle size were assessed. The optimized nanocrystal was characterized by its morphology, crystallinity, molecular interactions, saturation solubility, and dissolution properties. At optimized process conditions of milling at 500 rpm for 18 cycles of grinding with 0.3 - 0.4 mm zirconium oxide beads, minimum particle size, and PDI values were 281.21 nm and 0.22, respectively. Nanocrystals showed rod-like nanostructures, and XRD scans confirmed a decrease in drug crystallinity. The optimized formulation showed increased solubility and dissolution rate, as well as good physical stability. Particle size reduction by media milling technique was an efficient method for the solubility enhancement of hydrophobic drugs.

Predicting coarse-grained chromatin polymer properties from nucleosome-level contact data.

Making coarse-grained chromatin models is essential to interpret experimental data and to simulate and predict chromatin organization/dynamics. It is common to model chromatin as a bead spring chain, with each bead representing lengths 1kb, 10kb, or 100kb of the genome. However, we do not know the physical dimensions (radius) of these beads and the properties (stretching elasticity, bending elasticity, etc.) of the chain. To bridge this gap, we simulated a large ensemble of chromatin configurations at near-nucleosome (200bp) resolution, consistent with recently published Micro-C data. We then systematically coarse-grained the configurations and predicted quantities essential for chromatin polymer representation. We predict the size (physical dimension) of chromatin beads for a range of scales from 1kb to 100s of kb and compute various polymer properties such as stretching elasticity, bending fluctuations, and intrinsic angle among polymer beads. Unlike the prevalent notion, we show that coarse-grained chromatin polymer beads should be considered as soft particles that can overlap, and we propose an overlap parameter. We show that accounting for such overlap is necessary to predict 3D distances from simulations accurately. Our results also show how chromatin polymer properties vary along the genome depending on the local chromatin state.