Size Control Research Articles

Particle size control and performance analysis of the ammonium perchlorate-based molecular perovskite energetic material

To solve the problem of high mechanical sensitivity and difficulty in coating caused by large crystal particles of ammonium perchlorate-based molecular perovskite energetic material (H2dabco)[NH4(ClO4)3] (DAP-4), we conducted research on the particle size regulation and performance of it. Firstly, we determined the solubility of DAP-4 in six commonly used organic solvents using a static method. And based on this data, an UDAP-4 (D50 = 6.19 μm) was successfully prepared. The characterization results of UDAP-4 revealed that UDAP-4 exhibits a decrease in thermal decomposition peak temperature (Tp) by 19 °C compared to the raw material, along with an 87.92kJ/mol reduction in activation energy (Ea). The studies on different particle sizes indicate that UDAP-4 maintains good thermal stability while significantly enhancing safety performance. UDAP-4 shows an over 20J increase in impact sensitivity, and a 12N increase in minimum frictional load. And the smaller the particle size, the lower the sensitivity. These findings provide a reference for further secure applications of DAP-4 in an academic context.

Stimuli-responsive self-regulating assembly of chiral colloids for robust size and shape control.

Most synthetic self-assemblies grow indefinitely into size-unlimited structures, whereas some biological self-assemblies autonomously regulate their size and shape. One mechanism of such self-regulation arises from the chirality of building blocks, inducing their mutual twisting that is incompatible with their long-range ordered packing and thus halts the assembly's growth at a certain stage. This self-regulation occurs robustly in thermodynamic equilibrium rather than kinetic trapping, and therefore is attractive yet elusive. Until now, studies of self-regulating assemblies have focused on non-responsive systems, whose equilibrium point and corresponding size and shape are hardly changeable. Here, we demonstrate a stimuli-responsive, self-regulating assembly. This assembly consists of chiral and magnetically orientable nanorods, where the effective chirality can be changed by balancing chirality-induced twisting and magnet-induced flattening between nanorods. Consequently, the strength of self-regulation in the assembly is modulable by magnetic field intensity, allowing robust, tunable, and reversible control of its size and shape. Our strategy would provide more biomimetic materials with precision and responsiveness.

Microfluidic Bubble-Templating Multinozzle 3D Printing for Preparations of Macroporous Hydrogels with Ordered Pores of Large Size Ranges.

A strategy for fabrication of macroporous hydrogels through 3D printing assisted by molding and multiple microfluidic bubble-templating nozzles is proposed here. This approach aims to address the challenges faced by methods for 3D printing macroporous hydrogels, such as difficulties in precisely controlling the spatial distribution of macropores, limited porosity, and low resolution of external boundaries due to the poor mechanical properties of hydrogel solutions as printing ink. In this method, fast-switching microfluidic bubble-templating nozzles of varying sizes allowed for precise control of target pore sizes over a wide range. Cavities of polydimethylsiloxane (PDMS) molds were used to define the overall external shape of the hydrogels and enhance the resolution of the boundaries. During the printing process, the laminar shear force generated by a coaxial microfluidic system generated microbubbles which were then injected into the PDMS mold cavities. The spatial distribution of the microbubble clusters within the cavities was controlled by a 3D motion module. Finally, macroporous hydrogels with a pore size range of 238-930 μm were fabricated while avoiding millimeter round corners on the boundaries. A control precision of pore sizes was about 60 μm. Most importantly, this strategy broke through the space occupancy limitations of pores in traditional 3D printing methods for macroporous hydrogels. The space occupancy of pores could reach a maximum of about 87% within a single layer.

Bubble-Assisted Sample Preparation Techniques for Mass Spectrometry.

This review delves into the efficacy of utilizing bubbles to extract analytes into the gas phase, offering a faster and greener alternative to traditional sample preparation methods for mass spectrometry. Generating numerous bubbles in liquids rapidly transfers volatile and surface-active species to the gas phase. Recently, effervescence has found application in chemical laboratories for swiftly extracting volatile organic compounds, facilitating instantaneous analysis. In the so-called fizzy extraction, liquid matrices are pressurized with gas and then subjected to sudden decompression to induce effervescence. Alternatively, specifically designed effervescent tablets are introduced into the liquid samples. In situ bubble generation has also enhanced dispersion of extractant in microextraction techniques. Furthermore, droplets from bursting bubbles are collected to analyze non-volatile species. Various methods exist to induce bubbling for sample preparation. The polydispersity of generated bubbles and the limited control of bubble size pose critical challenges in the stability of the bubble-liquid interface and the ability to quantify analytes using bubble-based sample preparation techniques. This review covers different bubble-assisted sample preparation methods and gives practical guidance on their implementation in mass spectrometry workflows. Traditional, offline, and online approaches for sample preparation relying on bubbles are discussed. Unconventional bubbling techniques for sample preparation are also covered.

Stable Millivolt Range Resistive Switching in Percolating Molybdenum Nanoparticle Networks.

To overcome the limitations of the conventional Von Neumann architecture, inspiration from the mammalian brain has led to the development of nanoscale neuromorphic networks. In the present research, molybdenum nanoparticles (NPs), which were produced by means of gas phase condensation based on magnetron sputtering, are shown to be the constituents of electrically percolating networks that exhibit stable, complex, neuron-like spiking behavior at low potentials in the millivolt range, satisfying well the requirement of low energy consumption. Characterization of the NPs using both scanning electron microscopy and scanning transmission electron microscopy revealed not only pristine shape, size, and density control of Mo NPs but also a preliminary proof of the working mechanism behind the spiking behavior due to filament formations. Furthermore, electrostatics COMSOL Multiphysics simulations of the morphology of the NPs provided evidence that the stable switching is due to the as-deposited stellate Mo NPs creating high electric field strengths, while keeping them separated, not seen before in other percolating networks based on spherical NPs. Hence, our results show the working mechanism behind switching in percolating Mo NP networks and show that they are very promising for realistic neuromorphic systems.

Redispersible Acrylic Ester Polymers: Effect of Polymer Property Changes Due to Polymerization Method Modification and Functional Additives on the Performance of Polymer Cement Mortar

This paper presents an experimental study aimed at improving the performance of polymer cement mortar by evaluating the properties of acrylic ester redispersible polymers, synthesized using a change in polymerization method from emulsion monomer to monomer dropwise addition methods, along with the use of a functional additive in the form of a foaming agent. To achieve the research objectives, a polymer with a glass transition temperature of −11 °C was synthesized by fixing the monomer ratio, particle-size distribution, and glass transition temperature, and the physical properties of the polymer cement mortar were assessed. The results showed that polymers synthesized using the modified polymerization method increased elongation at break and possessed a 35% smaller average particle size. The use of the foaming agent also resulted in enhanced tensile strength. The polymer cement mortars made with these respective polymers demonstrated improvements in compressive strength 11~25%, flexural strength 53~77%, bond strength 78~113%, volumetric changes 65~88%, and water absorption 30~70%. These findings suggest that changes in the polymerization method and the incorporation of functional additives influence the average particle size and air entrainment control properties of the polymers, thereby positively impacting the performance of the cement hydrates.

Precision Macroporous Monoliths Made Using High‐Throughput Microfluidic Emulsification

Materials with pore sizes ranging from micrometers to millimeters find use in thermal insulation, acoustics, separation, and energy‐related applications. While several routes have been developed to manufacture such macroporous materials, current fabrication technologies remain limited in either scalability or pore size control. Herein, a scalable microfluidic approach is reported to create macroporous materials with precisely controlled pore sizes from monodisperse emulsion templates. Emulsion droplets produced in a parallelized step emulsification device are assembled by gravity and converted into macroporous monoliths by polymerization and drying. Microstructural analysis and model filtration experiments show that the pore windows of the bulk macroporous material can be tightly controlled and used for the size‐selective separation of particles from suspensions. By heat treating macroporous structures of selected compositions, one can also create bulk carbon and silica glass monoliths with unique cellular architectures for potential applications as filters, separation membranes, or catalyst supports.

High-Throughput Measurement of Single-Fission Yeast Cell Volume Using Fluorescence Exclusion.

Cell volume is a critical parameter for the biology of living species and has an impact on virtually all cellular functions. In Schizosaccharomyces pombe, the regulation of cell size has been the focus of intense investigation, and mechanisms that couple size control with cell cycle progression have been identified. In fission yeast, cell length at division is generally used as a proxy for determining cell size. However, it only allows for an inaccurate evaluation of this critical parameter and neglects potential changes in cell morphology and diameter, which can strongly impact cell volume. Until recently, one of the major obstacles for studying the complexity of cell size regulation in fission yeast has been the lack of a robust method for high-throughput, direct measurement of single-cell volume. Here, we provide a comprehensive protocol for S. pombe cell volume determination based on the Fluorescence eXclusion method and microfluidics technologies. This approach makes it possible to reliably describe cell volume and its distribution in populations of fission yeast cells.

Rebuilding Peripheral F, Cl, Br Footprints on Acceptors Enables Binary Organic Photovoltaic Efficiency Exceeding 19.7.

Given homomorphic fluorine, chlorine and bromine atoms are featured with gradually enlarged polarizability/atomic radius but decreased electronegativity, the rational screen of halogen species and location on small molecular acceptors (SMAs) is quite essential for acquiring desirable molecular packing to boost efficiency of organic solar cells (OSCs). Herein, three isomeric SMAs (CH-F, CH-C and CH-B) are constructed by delicately rebuilding peripheral F, Cl, Br footprints on both central and end units. Such a re-permutation of peripheral halogens could not only maintain the structural symmetry of SMAs to the maximum, but also acquire extra asymmetric benefits of enhanced dipole moment and intramolecular charge transfer, etc. Moreover, central brominating enhances molecular crystallinity of CH-B without introducing undesirable steric hindrance on end groups, thus rendering a better balance between high crystallization and domain size control in PM6:CH-B blend. Further benefitting from the large dielectric constant, small exciton binding energy, optimized molecular packing and great electron transfer integral, CH-B affords the first class binary OSC efficiency of 19.78%, moreover, the highest efficiency of 18.35% thus far when increasing active layer thickness to ~300 nm. Our successful screening in rebuilding peripheral halogen footprints provides the valuable insight into further rational design of SMAs for record-breaking OSCs.

Rebuilding Peripheral F, Cl, Br Footprints on Acceptors Enables Binary Organic Photovoltaic Efficiency Exceeding 19.7%

Given homomorphic fluorine, chlorine and bromine atoms are featured with gradually enlarged polarizability/atomic radius but decreased electronegativity, the rational screen of halogen species and location on small molecular acceptors (SMAs) is quite essential for acquiring desirable molecular packing to boost efficiency of organic solar cells (OSCs). Herein, three isomeric SMAs (CH‐F, CH‐C and CH‐B) are constructed by delicately rebuilding peripheral F, Cl, Br footprints on both central and end units. Such a re‐permutation of peripheral halogens could not only maintain the structural symmetry of SMAs to the maximum, but also acquire extra asymmetric benefits of enhanced dipole moment and intramolecular charge transfer, etc. Moreover, central brominating enhances molecular crystallinity of CH‐B without introducing undesirable steric hindrance on end groups, thus rendering a better balance between high crystallization and domain size control in PM6:CH‐B blend. Further benefitting from the large dielectric constant, small exciton binding energy, optimized molecular packing and great electron transfer integral, CH‐B affords the first class binary OSC efficiency of 19.78%, moreover, the highest efficiency of 18.35% thus far when increasing active layer thickness to ~300 nm. Our successful screening in rebuilding peripheral halogen footprints provides the valuable insight into further rational design of SMAs for record‐breaking OSCs.

Lights on the Synthesis of Surfactant-Free Colloidal Gold Nanoparticles in Alkaline Mixtures of Alcohols and Water.

Surfactant-free colloidal syntheses in aqueous media are attractive to develop nanomaterials relevant for various applications, e. g. catalysis or medicine. However, controlled green syntheses without surfactants of metal nanoparticles in aqueous media remain scarce. Here, room temperature syntheses of gold (Au) nanoparticles (NPs) that require only HAuCl4, alkaline water and an alcohol, i. e. relatively benign chemicals and mild reaction conditions, are developed. The findings of a comprehensive multi-parameters screening performed in small volumes (<3 mL) over 1000+ experiments pave the way to greener high throughput screenings of large parametric spaces and lead to scalable (100 mL) synthetic strategies. A rational selection of the alcohol is proposed. The influence of lights with defined wavelengths (222-690 nm) is investigated. It is found that lights with lower wavelengths favor the formation of smaller 5 nm NPs. Different kinetics and formation pathways are observed for different alcohols and for lights with different wavelengths. The sensitivity to various experimental parameters increases with the alcohol used in the order glycerol<ethylene glycol<ethanol<methanol. New strategies for a rational fine size control, and to some extend shape control, are identified. The results lead to more sustainable and reproducible surfactant-free colloidal syntheses of NPs.

Global Optimization of Molybdenum Subnanoclusters on Graphene: A Consistent Approach toward Catalytic Applications.

The development of novel subnanometer clusters (SNCs) catalysts with superior catalytic performance depends on the precise control of clusters' atomistic sizes, shapes, and accurate deposition onto surfaces. The intrinsic complexity of the adsorption process complicates the ability to achieve an atomistic understanding of the most relevant structure-reactivity relationships hampering the rational design of novel catalytic materials. In most cases, existing computational approaches rely on just a few structures to draw conclusions on clusters' reactivity thereby neglecting the complexity of the existing energy landscapes thus leading to insufficient sampling and, most likely, unreliable predictions. Moreover, modeling of the actual experimental procedure that is responsible for the deposition of SNCs on surfaces is often not done even though in some cases this procedure may enhance the significance of certain (e.g., metastable) adsorption geometries. This study proposes a novel systematic approach that utilizes global search techniques, specifically, the particle swarm optimization (PSO) method, in conjunction with ab initio calculations, to simulate all stages in the beam experiments, from predicting the most relevant SNCs structures in the beam and on a surface, to their reactivity. To illustrate the main steps of our approach, we consider the deposition of Molybdenum SNC of 6 Mo atoms on a free-standing graphene surface, as well as their catalytic properties with respect to the CO molecule dissociation reaction. Even though our calculations are not exhaustive and serve only to produce an illustration of the method, they are still able to provide insight into the complicated energy landscape of Mo SNCs on graphene demonstrating the catalytic activity of Mo SNCs and the importance of performing statistical sampling of available configurations. This study establishes a reliable procedure for performing theoretical rational design predictions.

Mini-review on laser-induced nanoparticle heating and melting

The development of various nanomaterials production technologies has led to the possibility of producing nanoparticles (NPs) and nanostructures, which can find a wide range of applications, from the fabrication of microelectronic devices to the improvement of material properties and the treatment of cancer. The unique characteristics of nanoparticles are primarily due to their small size, which makes size control important in their preparation. Modification of nanoparticles by laser irradiation and obtaining desired nanoparticle properties is a promising approach because of its ease of implementation. The purpose of this review is to analyze the works devoted to the study of laser-induced heating and melting of nanoparticles, to collect information and evaluate the results of using this method for functionalization and modification of metallic nanoparticles, and to discuss promising directions for the use of this technique.

The E3 ligase OsPUB33 controls rice grain size and weight by regulating the OsNAC120-BG1 module.

Grain size and weight are important determinants of crop yield. Although the ubiquitin pathway has been implicated in the grain development in rice (Oryza sativa), the underlying genetic and molecular mechanisms remain largely unknown. Here, we report that the Plant U-box (PUB) E3 ubiquitin ligase OsPUB33 interferes with the OsNAC120-BG1 module to control rice grain development. Functional loss of OsPUB33 triggers elevated photosynthetic rates and greater sugar translocation, leading to enhanced cell proliferation and accelerated grain filling. These changes cause enlarged spikelet hulls, thereby increasing final grain size and weight. OsPUB33 interacts with transcription factor OsNAC120, resulting in its ubiquitination and degradation. Unlike OsPUB33, OsNAC120 promotes grain size and weight: OsNAC120-overexpression plants harbor large and heavy grains, whereas osnac120 loss-of-function mutants produce small grains. Genetic interaction analysis supports that OsPUB33 and OsNAC120 function at least partially in a common pathway to control grain development, but have opposite functions. Additionally, OsNAC120 transcriptionally activates BIG GRAIN1 (BG1), a prominent modulator of grain size, whereas OsPUB33 impairs the OsNAC120-mediated regulation of BG1. Collectively, our findings uncover an important molecular framework for the control of grain size and weight by the OsPUB33-OsNAC120-BG1 regulatory module and provide promising targets for improving crop yield.

Efficient recovery of Pd(II) from nuclear wastewater using a functionalized covalent organic frameworks with uniform spherical structure: Size control, performance and mechanism insight

The efficient recovery of palladium from the spent nuclear fuel was of great significance to the sustainable development of nuclear energy. Herein, the uniform spherical COFs were constructed by a facile approach at room temperature, which were further surface functionalized by a thiol-ene “click” reaction to recover Pd(II). Microscopic and spectroscopic studies manifested that the formation mechanism and size of spherical COFs were greatly affected by the amount of catalyst and solvent type. The TAPB-BPTA-DTT and TAPB-BPTA-S-β-CD exhibited high Pd(II) recovery efficiency due to the introduction of sulfhydryl groups, and the maximum adsorption capacities were 489.3 and 234.3 mg/g, respectively. Meanwhile, the water environmental condition played an important role in the separation process, and the classical adsorption models demonstrated that monolayer chemisorption was the dominant removal mechanism. Mechanism analysis showed that the excellent adsorption performance was mainly attributed to the electrostatic interaction, physical absorption and chelation of N, O, and S groups with Pd(II). Thus, it is expected that this work could provide more insight into COFs materials, thereby promoting palladium removal advancements in the spent nuclear fuel.

TOWARDS THE DESIGN OF LIGANDS OF THE INTERNAL POCKET TEADS C-TERMINAL DOMAIN

The Hippo pathway controls in organ size and tissue homeostasis through regulating cell growth, proliferation and apoptosis. Phosphorylation of the transcription co-activator YAP (Yes associated protein) and TAZ (Transcriptional coactivator with PDZ-binding motif) regulates their nuclear import and therefore their interaction with TEAD (Transcriptional Enhanced Associated Domain). YAP, TAZ and TEADs are dysregulated in several solid cancers making YAP/TAZ-TEAD interaction a new anti-cancer target. We identified by screening a small in-house library, 5-benzyloxindole which binds to hTEAD2 at its internal/palmitate pocket. Its optimization led to covalent inhibitors bearing different warhead. Soaking with hTEAD2 gave seven new crystal structures where the ligands occupied palmitate pocket. 5-Benzyloxyindoles armed with vinylsulfamide moiety inhibit YAP/TAZ-TEAD target genes expression and breast cancer cell proliferation at micromolar concentration.

Development of a live cell assay for real-time monitoring the interactions between the Hippo pathway components 14-3-3 and TAZ

The Hippo pathway plays an important role in organ size control and tissue homeostasis. Dysregulation is involved in many pathologies, including cancer, which has attracted interest in targeting the Hippo pathway. Since the upstream components are bona fide tumor suppressors, it is feasible to target oncogenic downstream targets such as TAZ, a key downstream effector in the Hippo pathway. Its activity is regulated by phosphorylation on multiple sites, with Ser89 playing a critical role in regulation of TAZ activity. Phosphorylation of TAZ at Ser89 promotes binding to 14-3-3 scaffolding proteins, preventing nuclear translocation and abolishing target gene transcription. Here we describe the development of a cell-based assay suitable for high-throughput screening, based on a split NanoLuc luciferase, for monitoring interactions between 14-3-3 and TAZ in living cells. We have validated the assay by screening of a kinase-biased library. The assay can be quickly adapted for higher throughput and thus offers a valuable tool to study new signal inputs involved in regulation of TAZ activity as well as for identification of molecules that modulate the Hippo pathway.

Scene-aware Foveated Rendering.

We propose a new scene-aware foveated rendering method, which incorporates the scene awareness and characteristics of the human visual system into the mapping-based foveated rendering framework. First, we generate the conservative visual importance map that encodes the visual features of the scene, visual acuity, and gaze motion. Second, we construct the pixel size control map using a convolution kernel method. Third, we utilize the pixel size control map to guide the foveated rendering. At last, a temporal coherent refinement strategy is used to maintain the smooth foveated rendering for the adjacent frames. Compared to the state-of-the-art mapping-based foveated rendering methods using the same compression ratio, our method achieves smaller MSE, higher PSNR, and SSIM in the fovea, periphery, salient regions, and the whole image. We also conducted user studies, and the results proved that the perceptual quality of our method has a high visual similarity with the around truth rendered with the full resolution.

Carbon nanoarchitecture encapsulated highly dispersed ultrafine Ag particles composite anode for high-capacity desalination

The high capacity of silver (Ag) anodes positions them as a promising avenue for addressing pressing water purification challenges through capacitive deionization (CDI). However, it faces significant challenges such as severe volume expansion and particle crushing, leading to rapid electrochemical failure. Herein, hierarchical hybrid structures comprising highly dispersed ultrafine Ag anchored in carbon nanolayers were prepared using a temperature-mediated strategy. The coordination effect of organic precursors reduces the surface energy of Ag nanoparticles, effectively preventing aggregation during heat treatment. Carbon layer encapsulation synergized with particle size control effectively suppresses the absolute volumetric strain of the electrode in the electrochemical reaction, enhancing electrochemical stability. When used as a CDI anode, AgNC-500 demonstrated an excellent Cl- capturing capacity of 159.96 mg g-1 and a rate of 27.53 mg g−1 min−1. Furthermore, the capacity exhibited excellent stability with negligible degradation over 50 cycles. This study offers crucial insights for advancing the development of highly stable conversion electrodes.

An Analysis of Differential Evolution Population Size

The performance of the differential evolution algorithm (DE) is known to be highly sensitive to the values assigned to its control parameters. While numerous studies of the DE control parameters do exist, these studies have limitations, particularly in the context of setting the population size regardless of problem-specific characteristics. Moreover, the complex interrelationships between DE control parameters are frequently overlooked. This paper addresses these limitations by critically analyzing the existing guidelines for setting the population size in DE and assessing their efficacy for problems of various modalities. Moreover, the relative importance and interrelationship between DE control parameters using the functional analysis of variance (fANOVA) approach are investigated. The empirical analysis uses thirty problems of varying complexities from the IEEE Congress on Evolutionary Computation (CEC) 2014 benchmark suite. The results suggest that the conventional one-size-fits-all guidelines for setting DE population size possess the possibility of overestimating initial population sizes. The analysis further explores how varying population sizes impact DE performance across different fitness landscapes, highlighting important interactions between population size and other DE control parameters. This research lays the groundwork for subsequent research on thoughtful selection of optimal population sizes for DE algorithms, facilitating the development of more efficient adaptive DE strategies.