Bead Size Research Articles

Separation of Lung Cancer Cells From Mixed Cell Samples Using Aptamer-Modified Magnetic Beads and Permalloy Micromagnets.

This study involved the design and fabrication of a microfluidic chip integrated with permalloy micromagnets. The device was used with aptamer-modified magnetic beads (MBs) of various sizes to successfully separate lung cancer cells from a mixture of other cells. The overall separation efficiency was evaluated based on the ratios of cells in the different outlets and inlets of the chip. The results showed efficiencies ranging from 43.4% to 50.2% for MB sizes between 1.36 and 4.50 µm. Interestingly, efficiency slightly decreased as the size of the MBs increased, contrary to predictions. Further examination revealed that larger MBs exerted gravitational force on the cell-bound MBs at low flow rates, causing the targets to settle before reaching the main microchannel region. This was attributed to fluidic resistance caused by a size mismatch between the inlet tube and the microfluidic conduit. An increase in cell accumulation at the inlet was observed with larger MB sizes due to gravity. Therefore, the definition of effective separation efficiency was revised to exclude the effect of cell accumulation at the inlet. Effective separation efficiencies were found to be 71.6%, 76.4%, and 79.4% for MB sizes of 1.36, 3.00, and 4.50µm, respectively. The study concluded that larger MBs interacted more with the magnetic force, resulting in better separation. However, cells with smaller MBs were more likely to evade the magnetic force. The investigation provides valuable insights into isolating lung cancer cells using this method, with the potential for clinical application in cancer diagnosis and treatment.

Effects of Glass Bead Size on Dissolution Profiles in Flow-through Dissolution Systems (USP 4).

The effects of glass bead size in the conical space of flow-through cells on the dissolution profiles were investigated in a USP apparatus 4. Dissolution tests of disintegrating and non-disintegrating tablets in flow-through dissolution systems were performed using semi-high precision glass beads with diameters ranging from 0.5mm to 1.5mm. Computational fluid dynamics (CFD) was used to evaluate the effect of shear stress from the dissolution media flow. The use of smaller glass beads in a larger cell resulted in a faster dissolution of the model formulations under certain test conditions. The effect on the dissolution was highly dependent on the size of the beads in the top layer, including those in contact with the tablets. The absence of a bead-size effect on the dissolution of an orodispersible tablet in a small cell can be explained by the floating fragments during the test. CFD analysis showed that smaller bead diameters led to greater shear stress on the tablet, which was correlated with the dissolution rate. Hence, fluid flow through the narrow gaps between the small beads generated strong local flows, causing shear stress. The size of the glass beads used in flow-through cells affects the dissolution rate of tablets by altering the shear stress on the tablets in certain cases (e.g., direct deposition of the formulation on glass beads, large cells, and very low flow rates). Thus, glass bead size must be considered for a robust dissolution test in a flow-through cell system.

Synthesis of Black Seed Oil-loaded-, Alginate-based, pH-sensitive Beads Using Electrospraying Technique.

Black seed oil (BSO), derived from the seeds of the Nigella sativa plant, has garnered attention for its potential anti-cancer properties, particularly in the context of colon cancer. Its active compound, thymoquinone, may help inhibit cancer cell growth and induce apoptosis in colon cancer cells. Additionally, black seed oil's anti-inflammatory and antioxidant effects could contribute to a healthier gut environment, potentially reducing cancer risk. Therefore, this study synthesized pH-sensitive alginate beads to deliver BSO into the colon in a controlled-release manner without releasing the drug at pH 1.2 (stomach), thus providing a well-defined release pattern at pH 6.8. The use of electrospray technology improves process performance by making it easier to formulate small, homogeneous beads with a higher rate of swelling and diffusion in the gastrointestinal medium. The formulated beads were characterized by an ex-vivo mucoadhesive strength test, bead size, sphericity factor (SF), encapsulation efficiency (EE), scanning electron microscope (SEM), in vitro swelling behavior (SB), and in vitro drug release in acidic and buffer media. All these manufactured beads demonstrated modest sizes of 0.58 ± 0.01 mm and spherical shape of 0.03 ± 0.00 mm in this testing. The formulation showed promising floating and releasing properties in vitro. With a very low cumulative percentage of beads, the oil EE of 90.13% ± 0.93% was high, and the release study demonstrated more than 90% in pH 6.8 with good floating nature in the stomach. Additionally, the beads were evenly spaced throughout the intestine. The electrospraying approach used in this protocol can be reproducible, yielding consistent outcomes. Therefore, this protocol can be used for large-scale production for commercialization purposes.

Extraction, Characterization, and Encapsulation of Cinnamon Hydrosol Obtained via Microwave-Assisted Hydrodistillation: Analysis of Antioxidant and Antimicrobial Activities

Microwave-assisted hydrodistillation (MAHD) method was employed to extract cinnamon oil and hydrosol (a byproduct). The total polyphenol content (TPC) of the cinnamon hydrosol (CH) was determined using the Folin-Ciocalteu method, and its antioxidant power was assessed through the DPPH radical reduction method. Gas chromatography was utilized to quantify the main bioactive compound (cinnamaldehyde). The disc agar diffusion method was applied to evaluate the inhibition of pathogenic microorganisms. To protect the bioactive compound, an encapsulation method involving cross-linking with calcium alginate was utilized. The capsules were examined using environmental scanning electron microscopy (ESEM). The TPC content was found to be 15.63 ± 0.21 mg gallic acid/g dry matter, and the DPPH radical inhibition rate was 84.26 ± 1.35%. CH exhibited a significant inhibitory effect against Escherichia coli, and a moderate inhibition effect against Shigella flexneri, Salmonella spp., Salmonella typhimurium, and Escherichia coli EPEC. Finally, successful encapsulation of CH was achieved using sodium alginate, resulting in bead sizes ranging between 1.75 and 2.75 mm.

A Bronze Age Site on the Northern Coast of West Java

This study describes an early site on the northern coast of West Java, affected by the Austronesian culture—Subanglarang near Binong in the Subang Regency. Geologically, during the 2000–1000 BP interval, it was part of the coastline of the northern coast of West Java, situated more than 5 m asl. During the 2013 surveys and excavations in 2016 and 2018, five burials were revealed. On the basis of the fragments of red-slipped pottery, pickaxes, beads of various shape and size, and metal weapons, the site is dated to the Bronze Age. Artifacts similar to those of early Austronesians were discovered. The analysis of various beads from Subanglarang attests to trade relations with other areas. Further excavations on the northern coast of West Java will hopefully shed more light on the life of the Bronze Age people of that area.

Making connections: ostrich eggshell beads as indicators of precolonial societal interaction in southeastern southern Africa

ABSTRACT Ostriches are peculiar birds and their strangeness has been recognised by southern African hunter-gatherers through multiple symbolic associations. Such qualities are likely to have been enhanced where people had access to beads made from their eggshell but did not have direct knowledge of the birds themselves. Southeastern southern Africa, encompassing the Maloti-Drakensberg Mountains, the eastern half of the Eastern Cape Province and much of KwaZulu-Natal is one such area. We review the unusual attributes and associations of ostriches and their eggshell before briefly summarising previous work that has used strontium isotope analysis to investigate past bead exchange networks in this region. Because bead size can be controlled and patently varies through time and space, we then employ it as another potential indicator of the existence and spatial extent of past social networks. Having critically considered previous efforts in this field, we report on our work to build the largest sample of such data yet obtained in southern Africa and compare our preliminary results with other signals of interaction between precolonial hunter-gatherer and (where applicable) agropastoralist communities.

Stirred media mills of fine and ultrafine grinding for subsequent beneficiation operations

This paper presents a brief review of the designs, characteristics, and operating parameters of Stirred media mills supplied by foreign manufacturers. An analysis of information on Stirred media mills , which are used to improve the efficiency of beneficiation and metallurgical operations, is carried out using available publications. The obtained results indicate the inexpediency of using conventional drum ball mills for flotation separation of ores and concentrates with a fine interpenetration of minerals. The application of conventional mills in extraction of ores and concentrates resistant to cyanidation, where gold is finely disseminated in sulfides, is limited by their high power consumption and the corresponding operating costs. In this work, different types of Stirred media mills are considered, including their vertical and horizontal types. The advantages of Stirred media mills over conventional ball mills, particularly in terms of energy efficiency, are noted. The designs and main characteristics of Stirred media mills , which have received wide application, are presented. According to the data presented in the reviewed publications, the main parameters determining the grinding process in such mills are outlined, including the ratio of bead size to mill feed size, density of grinding medium, density of pulp in the mill, volume loading of beads, stirring speed, etc. The conducted analysis of literature data indicated high efficiency of mills based on agitation of grinding media for fine and ultrafine grinding of ores and concentrates in comparison with conventional ball mills. Given that the volume of ores and concentrates resistant to processing by conventional methods is increasing, the application of Stirred media mills is expected become more widespread, thereby increasing the efficiency of subsequent beneficiation and metallurgical operations.

Ultrasensitive detection of cancer-associated nucleic acids and mutations by primer exchange reaction-based signal amplification and flow cytometry

The detection of cancer-associated nucleic acids and mutations through liquid biopsy has emerged as a highly promising non-invasive approach for early cancer detection and monitoring. In this study, we report the development of primer exchange reaction (PER) based signal amplification strategy that enables the rapid, sensitive and specific detection of nucleic acids bearing cancer specific single nucleotide mutations using flow cytometry. Using micrometer size beads as support for immobilizing oligonucleotides and programmable PER assembly for target oligonucleotide recognition and fluorescence signal amplification, we demonstrated the versatile detection of target nucleic acids including KRAS oligonucleotide, fragmented mRNAs, and miR-21. Moreover, our detection system can discriminate single base mutations frequently occurred in cancer-associated genes including KRAS, PIK3CA and P53 from cell extracts and circulating tumor DNAs (ctDNAs). The detection is highly sensitive, with a limit of detection down to 27 fM without pre-amplification. In view of a clinical application, we demonstrate the detection of single mutations after extraction and pre-amplification of ctDNAs from the plasma of breast cancer patients. Importantly, our detection strategy enabled the detection of single KRAS mutation even in the presence of 1000-fold excess of wild type (WT) DNA using multi-color flow cytometry detection approach. Overall, our strategy holds immense potential for clinical applications, offering significant improvements for early cancer detection and monitoring.

Assessment of inhaled cationic antibiotics in an in vitro model of Pseudomonas aeruginosa lung biofilm

ObjectivesThis study aimed to evaluate the efficacy of inhaled cationic antibiotics, including tobramycin (TOB) and colistin (CST), using an in vitro alginate bead model that simulates Pseudomonas aeruginosa lung biofilms. MethodsBioluminescent P. aeruginosa were encapsulated within alginate beads and dispersed in either Mueller-Hinton broth (MHB) or artificial sputum medium (ASM). The impact of bead size and culture medium on TOB and CST efficacy was assessed by monitoring bioluminescence kinetics, followed by colony-forming unit (CFU/mL) measurements. Antibiotic efficacy was quantified using a Hill inhibitory model to analyze variations in CFU/mL in response to TOB and CST concentrations. ResultsThe TOB EC50 was found to be 8-fold higher when P. aeruginosa was encapsulated in larger beads (1200 μm) compared to smaller beads (60 μm). TOB efficacy further decreased twofold when larger beads were dispersed in ASM. In contrast, CST demonstrated superior efficacy, being four times more potent than TOB, with corresponding EC50 values of 20.5 ± 2.8 times MIC and 78.4 ± 10.2 times MIC, respectively. No change in MICs was observed for either antibiotic, even after exposing bacteria to 200 times the MIC. ConclusionsThis P. aeruginosa biofilm model highlights how alginate and mucus modulated the efficacy of TOB and CST, and suggested the superior efficacy of CST in eradicating pulmonary biofilms.

Temperature mapping of milling by dual centrifugation: A systematic investigation

Using low quantities of drug compounds is often favorable in the early stages of drug development, especially for what require a large screening investigation to define the final formulation composition, such as nano- and microsuspensions. For that reason, the dual centrifugation approach has in the recent years been used due to its reproducible and fast-milling capacity with 40 samples in 2 mL vials simultaneously without the addition of cooling breaks due to a built-in cooling system. Nonetheless, heat can be dissipated into the samples during high-intensity milling, resulting in increased sample temperatures that potentially can affect thermolabile compounds and potential influence the obtained suspensions in the screening experiments if the used stabilizer has temperature dependent variations in the performance. Hence, a systematic investigation of the influence of different process parameters on the heat dissipation in samples during milling by the dual centrifugation approach was performed in the present study. It was found that the milling speed had the highest impact on the final sample temperature, but also other parameters, such as the bead loading, bead size, and placement in the centrifuge during milling had significantly influenced the final mean temperature of the milling media. Higher temperatures were obtained with higher bead loadings, i.e., 3000 mg milling beads/mL and milling speeds (1500 rpm), and when smaller milling beads, i.e., 0.1 mm, were used during production. The study further showed that higher temperatures were measured for samples located on the bottom disk during milling, and also when located on the outer placement on the sample disk. Upscale investigations showed immensely increased sample temperatures (almost up to boiling point) when samples were prepared under similar formulation parameters and milling speed as small-volume vials. Furthermore, the study indicated that the addition of drug compounds during suspension preparation decreased the final sample temperature compared to samples that only contained purified water due to energy absorption of the drug compound.

The Langmuir-Blodgett trough (Langmuir film balance) can be used to understand the stabilizer concentrations in aqueous nano- and microsuspensions

Aqueous suspensions of poorly soluble, crystalline drug particles in the sub-micron range hold the ability to regulate the drug release for a defined period of time after e.g., intramuscular, or subcutaneous administration, working as an eminent formulation strategy for the preparation of long-acting injectables. Aqueous suspensions are typically prepared by top-down approaches, e.g., wet bead media milling or high-pressure homogenization, containing the active pharmaceutical compound and surfactants and/or polymers for stabilization purposes. Currently, the screening of proper stabilizers and adequate stabilizer concentration during formulation investigations is based on a trial-and-error approach with variations in combinations, concentrations, and/or ratios. To obtain a more efficient methodology during formulation screening, the present study investigated the correlation between the surface activity of two different surfactants, i.e., poloxamer 188 and polysorbate 20, by drop profile tensiometry and Langmuir trough monolayer, and the obtained sizes of cinnarizine particles as a tool to predict the optimal surfactant concentration to prepare physical stable nano- and microsuspensions. The obtained results demonstrated that the molecular area determined as the area per surfactant molecule measured in the Langmuir trough combined with the specific surface area of the prepared suspensions could be used to predict the suitable concentration of the surfactant based upon short-term stress stability data. The results further showed that higher concentrations of poloxamer 188 were necessary to stabilize the suspensions when compared to the needed concentration of polysorbate 20. In addition, it was observed that there was a need for a slightly higher surfactant concentration when the suspensions were milled with the smallest bead size of 0.5 mm instead of larger sizes of bead (0.8 and 1.0 mm), which could not be accounted for by differences in specific surface area.

Evaluation of Adsorption Ability of Lewatit® VP OC 1065 and Diaion™ CR20 Ion Exchangers for Heavy Metals with Particular Consideration of Palladium(II) and Copper(II).

The adsorption capacities of ion exchangers with the primary amine (Lewatit® VP OC 1065) and polyamine (Diaion™ CR20) functional groups relative to Pd(II) and Cu(II) ions were tested in a batch system, taking into account the influence of the acid concentration (HCl: 0.1-6 mol/L; HCl-HNO3: 0.9-0.1 mol/L HCl-0.1-0.9 mol/L HNO3), phase contact time (1-240 min), initial concentration (10-1000 mg/L), agitation speed (120-180 rpm), bead size (0.385-1.2 mm), and temperature (293-333 K), as well as in a column system where the variable operating parameters were HCl and HNO3 concentrations. There were used the pseudo-first order, pseudo-second order, and intraparticle diffusion models to describe the kinetic studies and the Langmuir and Freundlich isotherm models to describe the equilibrium data to obtain better knowledge about the adsorption mechanism. The physicochemical properties of the ion exchangers were characterized by the nitrogen adsorption/desorption analyses, CHNS analysis, Fourier transform infrared spectroscopy, the sieve analysis, and points of zero charge measurements. As it was found, Lewatit® VP OC 1065 exhibited a better ability to remove Pd(II) than Diaion™ CR20, and the adsorption ability series for heavy metals was as follows: Pd(II) >> Zn(II) ≈ Ni(II) >> Cu(II). The optimal experimental conditions for Pd(II) sorption were 0.1 mol/L HCl, agitation speed 180 rpm, temperature 293 K, and bead size fraction 0.43 mm ≤ f3 < 0.6 mm for Diaion™ CR20 and 0.315-1.25 mm for Lewatit® VP OC 1065. The maximum adsorption capacities were 289.68 mg/g for Lewatit® VP OC 1065 and 208.20 mg/g for Diaion™ CR20. The greatest adsorption ability of Lewatit® VP OC 1065 for Pd(II) was also demonstrated in the column studies. The working ion exchange in the 0.1 mol/L HCl system was 0.1050 g/mL, much higher compared to Diaion™ CR20 (0.0545 g/mL). The best desorption yields of %D1 = 23.77% for Diaion™ CR20 and 33.57% for Lewatit® VP OC 1065 were obtained using the 2 mol/L NH3·H2O solution.

Pectin-Chitosan Hydrogel Beads for Delivery of Functional Food Ingredients.

A common challenge in hydrogel-based delivery systems is the premature release of low molecular weight encapsulates through diffusion or swelling and reduced cell viability caused by the low pH in gastric conditions. A second biopolymer, such as chitosan, can be incorporated to overcome this. Chitosan is usually associated with colonic drug delivery systems. We intended to formulate chitosan-coated pectin beads for use in delaying premature release of the encapsulate under gastric conditions but allowing release through disintegration under intestinal conditions. The latter is of utmost importance in delivering most functional food ingredients. Therefore, this study investigated the impact of formulation and process conditions on the size, sphericity, and dissolution behavior of chitosan-coated hydrogel beads prepared by interfacial coacervation. The size and sphericity of the beads depend on the formulation and range from approximately 3 to 5 mm and 0.82 to 0.95, respectively. Process conditions during electro-dripping may be modulated to tailor bead size. Depending on the voltage, bead size ranged from 1.5 to 4 mm. Confocal laser scanning microscopy and scanning electron microscopy confirmed chitosan shell formation around the pectin bead. Chitosan-coated beads maintained their size and shape in simulated gastric fluid but experienced structural damage in simulated intestinal fluid. Therefore, they represent a novel delivery system for functional food ingredients.

Jet injection and spout formation in a fluidized bed

A single jet was studied in a rectangular fluidized bed by analyzing the pressure fluctuations data to characterize the jet hydrodynamics. The bed contained with glass beads of different mean sizes (450, 650, and 920 µm) as well as pharmaceutical pellets (920 µm). The analysis of the pressure fluctuation data was performed using the power spectral density function (PSDF) and discrete wavelet transforms technique. This study investigated how the flow regime changed from a jet in a fluidized bed to a spouted regime as the gas injection velocity was increased. Increasing the mean particle size led to an increase in the minimum spouting velocity. The minimum spouting velocity for 450, 650, and 920 μm glass bead particles and for 920 μm pharmaceutical pellets were determined to be 32.47 m s-1, 38.66 m s-1, 44.78 m s-1, and 44.47 m s-1, respectively. The study also examined how the dominant frequency of the various particles and the energy percentage of scales changed with increasing injection velocities. The ratio of energy percentages of meso-scale changes as the injection velocity increases and these changes were used to estimate the minimum spouting velocity. Wavelet sub-signals analysis revealed that the Daubechies 2 (DB2) wavelet was the most effective at capturing the characteristics of the jet. Based on the Shannon entropy of the approximate coefficients, the wavelet analysis showed that 11 levels of decomposition were required. By combining the wavelet analysis and PSDF, a more detailed analysis of the meso-scale was achieved. This study provided valuable insights into the behavior of jets and spouts in fluidized beds, which can greatly contribute to the optimization of a jet in fluidized beds and spout-fluidized beds by enhancing our understanding of jet behavior in such environments.

Nanocrystal formulations of mebendazole employing quality by design and molecular level insights by atomistic simulations

Objective The present study investigates the production of mebendazole nanocrystal formulations by wet media milling. Significance Nanocrystal formulations are expected to enhance the dissolution properties of mebendazole, which possesses poor solubility, highly dependent on crystal polymorphism. Methods A Box-Behnken design was employed to study the effects of formulation and process variables on the nanocrystal size and ζ-potential. The optimal nanosuspensions were solidified by spay-drying and freeze-drying with and without mannitol, and the effects of the drying method on the reconstitution of the nanosuspension was studied. Additionally, their physicochemical properties were determined, while the mechanism of fracture and stabilizer adsorption were investigated by atomistic simulations. Results Poloxamer 407 is the most suitable stabilizer, while the bead size, milling speed, and stabilizer content significantly affect the diameter. The ζ-potential is affected by the stabilizer concentration depending on bead size. Energy-vector diagrams revealed a slip plane in the lattice of form C, while molecular dynamics simulations revealed strong interactions between stabilizer and crystal surface. Both drying processes induce polymorphic transformation to form A, which, however, can be partially prevented by the addition of mannitol in freeze-drying, at the expense of suspension redispersibility. The spray-dried nanosuspensions exhibited substantially enhanced dissolution profile compared to neat mebendazole, probably due to reduction of particle size, despite transformation to the unfavorable form A. Conclusions Nanocrystal formulations exhibited significant dissolution enhancement, while experimental design and atomistic simulations provided useful insights into the mechanism of their formation and stability.

Experimental and modeling insights into mixing-limited reactive transport in heterogeneous porous media: Role of stagnant zones

The understanding of mixing-controlled reactive dynamics in heterogeneous porous media remains limited, presenting significant challenges for modeling subsurface contaminant transport processes and for designing cost-effective environmental remedial efforts. The complexity of accurately observing, measuring, and modeling mixing-limited reactive transport has led to inadequate exploration of these critical processes. This study investigates the mixing and reaction kinetics affected by stagnant zones, which are commonly found in alluvial aquifers-aquitards and fracture-matrix systems. By conducting experiments involving conservative and bimolecular reactive transport through porous media within translucent chambers filled with two sizes of glass beads and under varying flow rates, we explored the effects of grain size and hydrodynamic conditions. Using a high-resolution camera, we monitored the concentration changes of conservative and reactive tracers, with subsequent interpretation through three-dimensional numerical simulations. The outcomes revealed the emergence of distinct mixing interfaces within both mobile and stagnant zones, culminating in a bi-peaked plume formation. Notably, the mixing and reaction times in media containing stagnant zones were found to be approximately 10 times longer than in homogeneous media. These findings, through experimental and modeling efforts, advance our understanding of mixing-limited reactive transport phenomena within heterogeneous media, underscoring the significant role of stagnant zones—a topic previously underexplored.

BEAD SIZE AND RHEOLOGICAL PROPERTIES OF SEBS-BASED ELASTIC BEADS

ABSTRACT Styrene–ethylene–butylene–styrene (SEBS) is a thermoplastic elastomer that has applications in robotics and shock absorption. Although SEBS as a bulk material as well as an additive to solid composites has been extensively studied, this work focuses on developing SEBS-based beads to enhance material elasticity. SEBS bead mixtures were developed by mixing SEBS elastomer, water, and surfactant (Triton X-100) at high temperature. Stability, rheology, and microscopy of SEBS bead mixtures were studied as a function of neat SEBS concentration in SEBS elastomer, SEBS elastomer concentration, and surfactant concentration. Resulting bead mixtures were classified as creamed, homogenous and stable, or aggregated based on the mixture’s tendency to separate into layers and its ability to disperse in excess water. Microscopic studies suggest that although bead mixtures exhibit size polydispersity, the average bead size is a strong function of neat SEBS, SEBS elastomer, and surfactant concentrations. Rheological studies suggest that all the bead mixtures exhibit shear thinning behavior, and the overall viscosity of a given bead mixture is a function of both SEBS elastomer and surfactant concentration. The developed SEBS elastic beads can be used as additives to enhance the viscoelastic properties of fluid-based systems such as magnetorheological and damping fluids.

Experimental investigation of erosion and transport of binary sediment in sewer pipes

ABSTRACT Understanding sediment transport in storm sewer systems is essential to prevent pipe blockages, associated flooding, and maintenance. In this research, a laboratory study was conducted in a pipe to investigate the erosion and transport process of a binary sediment, i.e., a material with two different particle sizes. The sediment used in this study was a mixture of two sizes of spherical glass beads (0.8 and 4 mm) and two sizes of natural soil (sand and gravel), with different amounts of small size particles. The results show that the critical velocities for the initiation of sediment transport increase linearly with a decrease in the fine particle content of the mixture. A method to predict the critical velocity of a binary mixture is proposed based on the fine content and the critical velocity of single-size large particle and single-size small particle sediments. The transport rate of the mixture lies between that of the single-size large sediment and single-size small sediment. The transport rate is increased with an increase in the fine content, which means that mixing small particles with large particles can significantly increase the transport rate of large particles and the total transport rate.

The surface tension of Martini 3 water mixtures.

The Martini model, a coarse-grained forcefield for biomolecular simulations, has experienced a vast increase in popularity in the past decade. Its building-block approach balances computational efficiency with high chemical specificity, enabling the simulation of organic and inorganic molecules. The modeling of coarse-grained beads as Lennard-Jones particles poses challenges for the accurate reproduction of liquid-vapor interfacial properties, which are crucial in various applications, especially in the case of water. The latest version of the forcefield introduces refined interaction parameters for water beads, tackling the well-known artifact of Martini water freezing at room temperature. In addition, multiple sizes of water beads are available for simulating the solvation of small cavities, including the smallest pockets of proteins. This work focuses on studying the interfacial properties of Martini water, including surface tension and surface thickness. Employing the test-area method, we systematically compute the liquid-vapor surface tension across various combinations of water bead sizes and for temperatures from 300 to 350K. These findings are of interest to the Martini community as they allow users to account for the low interfacial tension of Martini water by properly adjusting observables computed via coarse-grained simulations to allow for accurate matching against all-atom or experimental results. Surface tension data are also interpreted in terms of local enrichment of the various mixture components at the liquid-vapor interface by means of Gibbs' adsorption formalism. Finally, the critical scaling of the Martini surface tension with temperature is reported to be consistent with the critical exponent of the 3D Ising universality class.

Optics-free reconstruction of 2D images via DNA barcode proximity graphs.

Spatial genomic technologies include imaging- and sequencing-based methods ( 1-3 ). An emerging subcategory of sequencing-based methods relies on a surface coated with coordinate-associated DNA barcodes, which are leveraged to tag endogenous nucleic acids or cells in an overlaid tissue section ( 4-7 ). However, the physical registration of DNA barcodes to spatial coordinates is challenging, necessitating either high density printing of coordinate-specific oligonucleotides or in situ sequencing/probing of randomly deposited, oligonucleotide-bearing beads. As a consequence, the surface areas available to sequencing-based spatial genomic methods are constrained by the time, labor, cost, and instrumentation required to either print, synthesize or decode a coordinate-tagged surface. To address this challenge, we developed SCOPE (Spatial reConstruction via Oligonucleotide Proximity Encoding), an optics-free, DNA microscopy ( 8 ) inspired method. With SCOPE, the relative positions of randomly deposited beads on a 2D surface are inferred from the ex situ sequencing of chimeric molecules formed from diffusing "sender" and tethered "receiver" oligonucleotides. As a first proof-of-concept, we apply SCOPE to reconstruct an asymmetric "swoosh" shape resembling the Nike logo (16.75 × 9.25 mm). Next, we use a microarray printer to encode a "color" version of the Snellen eye chart for visual acuity (17.18 × 40.97 mm), and apply SCOPE to achieve optics-free reconstruction of individual letters. Although these are early demonstrations of the concept and much work remains to be done, we envision that the optics-free, sequencing-based quantitation of the molecular proximities of DNA barcodes will enable spatial genomics in constant experimental time, across fields of view and at resolutions that are determined by sequencing depth, bead size, and diffusion kinetics, rather than the limitations of optical instruments or microarray printers.