Size Control Research Articles

Size Control of Chiral Nanospheres Obtained via Nanoprecipitation of Helical Poly(phenylacetylene)s in the Absence of Surfactants

AbstractNanostructuration of dynamic helical polymers such as poly(phenylacetylene)s (PPAs) depends on the secondary structure adopted by the polymer and the functional group used to connect the chiral pendant to the PPA backbone. Thus, while PPAs with dynamic and flexible scaffolds (para‐ and meta‐substituted, ω1<165°) generate by nanoprecipitation low polydisperse nanospheres with controllable size at different acetone/water mixtures, those with a quasi‐static behavior and the presence of an extended, almost planar structure (ortho‐substituted, ω1>165°), aggregate into a mixture of spherical and oval nanostructures whose size is not controlled. Photostability studies show that poly(phenylacetylene) particles are more stable to light irradiation than when dissolved macromolecularly. Moreover, the photostability of the particle depends on the secondary structure of the PPA and its screw sense excess. This fact, in combination with the encapsulation ability of these polymer particles, allows the creation of light stimuli‐responsive nanocarriers, whose cargo can be delivered by light irradiation.

PS@poly(NIPAM-co-AA) core@shell nanoparticles: size control and tuning of LCST

Here, we demonstrate a synthetic approach to precise size control of PNIPAM-based core@shell nanoparticles prepared by microemulsion polymerization as well as control of low critical solution temperature (LCST) of their water dispersions. The size of the PS-core can be tuned to ∼30 nm by a simple increase of mechanical stirring up to 1200 rpm, while the thickness of the thermoresponsive @poly(N-isopropyl acrylamide-co-acrylamide) shell can be controlled by varying the polymerization time. The effect of not only a molar ratio or co-monomer nature but also a strong influence of a thermoresponsive shell thickness on the LCST was found.

CMC-Ca(OH)2-TiO2 Nanocomposite for Paper Relics Multifunctional Restoration: Strengthening, Deacidification, UV Effect Resistance, and Antimicrobial Protection

In recent years, the demand for the protection and restoration of cultural heritage has become increasingly urgent. Particularly for paper-based cultural relics such as ancient books and paintings, their restoration is especially important due to their unique nature and susceptibility to environmental damage. Among various restoration materials, calcium hydroxide (Ca(OH)2) has been widely studied and applied in the protection of paper-based cultural relics. However, commercial Ca(OH)2 materials have issues such as a large particle size and slow carbonation. In order to address these issues, this study employed carboxymethyl cellulose (CMC) as a support, on which nano-sized Ca(OH)2 crystals were grown in situ on its surface, followed by loading with TiO2 nanoparticles, successfully preparing a multifunctional paper-based cultural relic restoration material with reinforcement, deacidification, anti-aging, and antimicrobial properties. It is worth noting that by in situ growing Ca(OH)2 on the surface of CMC, particle size control, uniform dispersion, and the fixation of Ca(OH)2 can be achieved. CMC is used to enhance the mechanical strength of the paper, Ca(OH)2 is used for deacidification, and TiO2 is used for anti-aging and antimicrobial purposes. This study provides a new approach and method for the restoration of paper-based cultural relics, simplifying traditional multi-step processes and avoiding potential impacts on the cultural relics from multiple repairs.

E-peroxone with a novel GDE decorated with hydrophobic membrane for the degradation of pyridine: Stability, byproducts and toxicity

E-peroxone process is an emerging electrochemical oxidation process, based on ozone and the in-situ cathodic generation of H2O2, but the stability of cathode is one of the key restraining factors. In this study, we designed a multilayer gas diffusion electrode (GDE) decorated with a commercial hydrophobic membrane for the degradation of pyridine. It was found that a proper control of membrane pore sizes and hot-pressing temperature can significantly promote the GDE stability. Subsequently, key operational parameters of the constructed E-peroxone system were investigated, including the ozone concentration, current density, pH value, electrolyte type and initial concentration of pyridine. The degradation pathways were proposed according to six identified transformation products. The toxicity variation along the degradation progress was evaluated with microbial respiration tests and Toxicity Estimation Software Tool (T.E.S.T.) calculation and an efficient detoxification capacity of E-peroxone was observed. This research provides a theoretical basis and technical support for the development of highly efficient and stable E-peroxone system for the elimination of toxic organic contaminants.

Transoral Ultrasound-Guided Core Biopsy for Minimally Invasive Sampling of Hard-to-Access Oropharyngeal Cancers.

Pathological diagnosis plays a pivotal role in risk classification and personalized treatment planning for patients with oropharyngeal cancers. However, challenges arise in cases involving trismus and tumors with submucosal spread, hindering traditional endoscopic biopsies and open incisional biopsies. In this study, we examined the clinical and pathological data of patients with trismus who underwent transoral ultrasound-guided core biopsy (USCB) for their oropharyngeal tumors, comparing this method with existing diagnostic approaches. Seventeen patients presenting with oropharyngeal tumors and trismus underwent transoral USCB for diagnosis. Of these, 14 patients were diagnosed with squamous cell carcinoma, while the remaining 3 were diagnosed with lymphoma. The procedure resulted in minimal wound size and effective bleeding control through compression, without encountering any complications. In conclusion, transoral USCB emerges as a precise diagnostic tool for patients with oropharyngeal tumors and trismus, offering a valuable adjunct to conventional open and endoscopic biopsies.

Addressing bioreactor hiPSC aggregate stability, maintenance and scaleup challenges using a design of experiment approach

BackgroundStem cell-derived therapies hold the potential for treatment of regenerative clinical indications. Static culture has a limited ability to scale up thus restricting its use. Suspension culturing can be used to produce target cells in large quantities, but also presents challenges related to stress and aggregation stability.MethodsUtilizing a design of experiments (DoE) approach in vertical wheel bioreactors, we evaluated media additives that have versatile properties. The additives evaluated are Heparin sodium salt (HS), polyethylene glycol (PEG), poly (vinyl alcohol) (PVA), Pluronic F68 and dextran sulfate (DS). Multiple response variables were chosen to assess cell growth, pluripotency maintenance and aggregate stability in response to the additive inputs, and mathematical models were generated and tuned for maximal predictive power.ResultsExpansion of iPSCs using 100 ml vertical wheel bioreactor assay for 4 days on 19 different media combinations resulted in models that can optimize pluripotency, stability, and expansion. The expansion optimization resulted in the combination of PA, PVA and PEG with E8. This mixture resulted in an expansion doubling time that was 40% shorter than that of E8 alone. Pluripotency optimizer highlighted the importance of adding 1% PEG to the E8 medium. Aggregate stability optimization that minimizes aggregate fusion in 3D culture indicated that the interaction of both Heparin and PEG can limit aggregation as well as increase the maintenance capacity and expansion of hiPSCs, suggesting that controlling fusion is a critical parameter for expansion and maintenance. Validation of optimized solution on two cell lines in bioreactors with decreased speed of 40 RPM, showed consistency and prolonged control over aggregates that have high frequency of pluripotency markers of OCT4 and SOX2 (> 90%). A doubling time of around 1–1.4 days was maintained after passaging as clumps in the optimized medium. Controlling aggregate fusion allowed for a decrease in bioreactor speed and therefore shear stress exerted on the cells in a large-scale expansion.ConclusionThis study resulted in a control of aggregate size within suspension cultures, while informing about concomitant state control of the iPSC state. Wider application of this approach can address media optimization complexity and bioreactor scale-up challenges.

Effects of solid electrolyte particle size and silver-carbon interlayer on lithium deposition in all-solid-state lithium-metal batteries

All-solid-state batteries with lithium-metal anodes are expected to exhibit high performance. For practical application, the growth of lithium dendrites must be suppressed. One method to suppress dendrite growth is to insert a carbon interlayer at the interface between the anode and solid electrolyte (SE). Dendrite growth is related to the anode interface properties and depends on the SE particle size used in the SE layer. Appropriate control of the SE particle size used at the anode interface can improve battery performance. In this study, the effects of SE particle size and carbon interlayer type on lithium-metal deposition morphology are investigated by X-ray CT measurement. The results show that dendrite growth is suppressed when the small-particle SE is used owing to the smaller pores between the SE layer and carbon interlayer. In addition, by controlling the SE particle size distribution using a double SE layer, both high ionic conductivity and dendrite suppression can be achieved. Furthermore, dendrite growth can be suppressed using a silver particle-added carbon interlayer, even with the large-particle SE where dendrites are prone to grow more easily.

Effects of Ce addition on inclusion modification in martensitic stainless steel

The control of inclusion features, i.e., chemical composition, distribution, quantity, and size, is in high demand for stainless steels to achieve good surface quality, pitting corrosion resistance, and mechanical properties. In this paper, the effects of rare earth (RE) modification on the inclusions of martensitic stainless steel were explored. Martensitic stainless steels with various contents of Ce were prepared, and the inclusions in the cast billets were characterized by field emission scanning electron microscopy (FE-SEM) and an automatic analysis system for nonmetallic inclusions in steels (OTS). The effect of Ce on the modification of nonmetallic inclusions during solidification was explored with thermodynamic calculations. The results showed that the addition of Ce modified the oxygen and sulfur inclusions by transforming them from irregular elongated inclusions to nearly spherical RE composite inclusions. Compared with those in basic martensitic stainless steel, nine types of RE inclusions were found in the presence of Ce. As the Ce content increased from 0.048 wt% to 0.092 wt%, the CeAlO3 content decreased, whereas the Ce2O2S content increased. Moreover, there were 80% fewer inclusions than in the basic martensitic stainless steel.

A National Database Study on Racial Disparities in Route of Hysterectomy with a Surrogate Control for Uterine Size: A Proposed Quality Metric for Benign Indications

Study ObjectiveTo investigate the association between race and route of hysterectomy among patients undergoing hysterectomy for abnormal uterine bleeding in the absence of uterine fibroid disease and excluding malignancy. DesignA cross-sectional cohort study utilizing the Healthcare Cost and Utilization Project Nationwide Inpatient Sample and National Ambulatory Surgical databases to compare abdominal to minimally invasive route of hysterectomy. SettingHospitals and hospital-affiliated ambulatory surgical centers participating in the Healthcare Cost and Utilization Project in 2019 Patients75,838 patients who had undergone hysterectomy for abnormal uterine bleeding excluding uterine fibroids and malignancy. Interventionsn/a Measurements and Main ResultsOf the 75,838 hysterectomies performed for abnormal uterine bleeding in the absence of uterine fibroids and malignancy, 10.1% were performed abdominally and 89.9% minimally invasively. After adjusting for confounders, Black patients were 38% more likely to undergo abdominal hysterectomy compared to White patients (OR 1.38, CI 1.12-1.70 p=0.002). Black race thus is independently associated with open surgery. ConclusionDespite excluding uterine fibroids as a risk factor for an abdominal route of hysterectomy, Black race remained an independent predictor for abdominal versus minimally invasive hysterectomy and Black patients were found to undergo a disproportionately higher rate of abdominal hysterectomy compared to White patients.

Control of the rubber particle size and phase structure for the design of transparent methacrylate-acrylonitrile-butadiene-styrene resin with excellent performance

Control of the rubber particle size and phase structure for the design of transparent methacrylate-acrylonitrile-butadiene-styrene resin with excellent performance

Enhanced electrochemical performance of the LiMn0.6Fe0.4PO4/C modified by secondary particle morphology control combined with primary particle size control

Enhanced electrochemical performance of the LiMn0.6Fe0.4PO4/C modified by secondary particle morphology control combined with primary particle size control

Metal dependence of spontaneous graphitization growth at room temperature

The low-temperature graphene growth is a crucial step toward more efficient, cost-effective, productive, cheap, and sustainable energy systems. In this work, we report the effect of transition metal nanoparticles (TMNPs) Ag, Pd, and Cu on the graphitization of amorphous carbon (a-C) deposited onto SiO2 substrates using a one-step magnetron sputtering technique at room temperature (RT). Transmission electron microscopy (TEM), Raman spectroscopy, and x-ray photoelectron spectroscopy (XPS) were used to examine the structures of TMNP-C films. The a-C around the metallic NPs spontaneously formed a disordered graphitic structure. Moreover, the 2D peak was detected in Raman spectra, and XPS analyses revealed the sp2 graphitization for the Ag-C, Pd-C, and Cu-C films deposited on the SiO2 substrates. These studies suggest that these metals’ graphitization activity is in the sequence of Pd > Cu > Ag. The highest catalytic activity of Pd NPs in graphitization at low temperatures was due to the highest carbon solubility and nano-sized particles. Thus, the control of the particle size of the catalyst to enhance the carbon solubility and decrease the melting point will open up a new strategy to grow high-quality graphene at low- temperatures.

Grain size control on organo-clay complexation and REE fractionation in the Paleozoic strata of the Permian Basin (West Texas, U.S.A.)

As a major component of mudstone, clay minerals are known to conserve organic matter (OM) as well as a range of trace elements through the mechanisms of adsorption, encapsulation, and/or intercalation. The associations of the clay minerals on one hand and trace elements and OM on the other hand impact the diagenetic evolution of such rocks and is of substantial importance for their characterization and assessment. Subsurface core samples collected from Late Paleozoic mudstone within the Permian Basin of Texas were separated into four grain size fractions (>2 µm, 2 to 1 µm, 1 to 0.6 µm, and <0.6 µm) to determine the clay mineralogy, OM abundances, and rock geochemistry using a suite of diffraction, spectroscopic, and chemical analysis. All separates were largely consisted of illite-smectite (I-S), illite-tobelite-smectite (I-T-S), mica/illite and chlorite coupled with some minor quartz and feldspar. The smectite component of I-S was shown to increase with decreasing grain size fractions. Additionally, t he rise in the content of smectite interlayers correlated with an increase in the total organic carbon (TOC) content towards the finest grain size separates in all samples. This suggested that a significant portion of the TOC content resided in the fraction below 2 µm and that smectite interlayers promoted the preservation of OM. Rare earth elements (REE) concentrations were found to be the highest in the finest grain size separates and align with an increased content of smectite interlayers, denoting a plausible interaction between the two. Further on, REE and TOC concentrations display a significant positive correlation in all size fractions and increase with respect to smectite interlayer content. This three-component relation suggests the REE adsorption to illite-smectite was likely promoted by OM. Understanding the close relation between the clay minerals, OM, and trace element content is indicative of polyvalent cationic bridging, ligand exchange, and organo-metallic complexation, which eventually l eads to the enrichment of OM and fractionation of REE in mudstone.

Synthesis and Emission Dynamics of Sub‐3 nm Upconversion Nanoparticles

AbstractReducing the size of upconversion nanoparticles (UCNPs) down to a few nm yields luminescent materials containing a very small number of emitters. Considering the bottom limit of one activator per particle ultrasmall UCNPs offer an unprecedented platform to study the contributions of the different energy transfers at play in upconversion luminescence. Maintaining detectable emission despite the limited number of emitting ions and the high surface‐to‐volume ratio requires suitable particle architectures. Na(Gd‐Yb)F4:Tm3+ emissive sub‐3 nm diameter β‐phase UCNPs are prepared using a gadolinium‐rich composition in situ mixing of the precursors and a microwave high‐temperature cycling sequence allowing precise control of the particle size and dispersity. These cores are coated with a NaGdF4 inert shell to minimize the deleterious influence of surface quenching (SQ). Time‐resolved luminescence measurements combining standard NIR excitation of the Yb3+ sensitizer and direct UV excitation of the Tm3+ activator are performed to quantify cross relaxation and surface quenching processes. The fine tuning of the number of activators per particle via an optimized synthesis pathway along with the use of an appropriate excitation scheme enabled to provide an accurate analysis of the different mechanisms at play in these model nanoparticles and to characterize the structure of the core‐shell architecture.

Piezo regulates epithelial topology and promotes precision in organ size control

Mechanosensitive Piezo channels regulate cell division, cell extrusion, and cell death. However, systems-level functions of Piezo in regulating organogenesis remain poorly understood. Here, we demonstrate that Piezo controls epithelial cell topology to ensure precise organ growth by integrating live-imaging experiments with pharmacological and genetic perturbations and computational modeling. Notably, the knockout or knockdown of Piezo increases bilateral asymmetry in wing size. Piezo's multifaceted functions can be deconstructed as either autonomous or non-autonomous based on a comparison between tissue-compartment-level perturbations or between genetic perturbation populations at the whole-tissue level. A computational model that posits cell proliferation and apoptosis regulation through modulation of the cutoff tension required for Piezo channel activation explains key cell and tissue phenotypes arising from perturbations of Piezo expression levels. Our findings demonstrate that Piezo promotes robustness in regulating epithelial topology and is necessary for precise organ size control.

Assessing the benefits of approximately exact step sizes for Picard and Newton solver in simulating ice flow (FEniCS-full-Stokes v.1.3.2)

Abstract. Solving the momentum balance is the computationally expensive part of simulating the evolution of ice sheets. The momentum balance is described by the nonlinear full-Stokes equations, which are solved iteratively. We use the Picard iteration and Newton's method combined with Armijo step sizes and approximately exact step sizes, respectively, to solve these equations. The Picard iteration uses either no step size control or the approximately exact step sizes. We compare the variants of Newton's method and the Picard iteration in benchmark experiments, called ISMIP-HOM experiments A, B, E1, and E2. The ISMIP-HOM experiments consist of a more realistic domain and are designed to test the quality of ice models. For an even more realistic test case, we simulate the experiments E1 and E2 with a time-dependent surface. We obtain that approximately exact step sizes greatly reduce the necessary number of iterations for the Picard iteration and Newton's method with nearly no increase in the computation time for each iteration.

Experimental design of size variation in albumin nanoparticles synthesized by electron beam

Protein-based nanoparticles have garnered significant interest for their potential in theranostic applications, including cancer treatment and nuclear medicine. Plasma proteins are particularly appealing due to their ability to bypass the rapid clearance typically associated with synthetic particles. Human serum albumin (HSA), for example, is already utilized in diagnostic procedures such as lymphoscintigraphy and sentinel lymph node detection and in cancer treatments where it delivers therapeutic agents in nanoparticulate form. Among the various techniques for synthesizing protein nanoparticles, ionizing radiation stands out for its ability to maintain good size control and preserve the protein's three-dimensional structure. Factors such as the reaction precursor, pH, protein concentration, presence of a stabilizer, and irradiation dose can all influence the size and shape of the resulting nanoparticles. This study sought to identify a correlation between the size of albumin nanoparticles and reaction parameters, including protein concentrations, the ionic content of the buffer solution, and the e-beam irradiation dose. We conducted different synthesis methods with varying BSA concentrations, using two different buffers and varying radiation doses. The resulting nanoparticles were evaluated using Dynamic Light Scattering. The size data were statistically analyzed using SAS Studio, SAS JMP, and WEKA software to identify correlations among the synthesis variables. Our observations primarily revealed that lower protein concentrations consistently resulted in smaller particles. Additionally, using Tris-HCl buffer as a medium led to a more proportional growth of particles with increases in concentration and irradiation dose. These findings suggest that Tris buffer is more suitable for BSA nanoparticle synthesis, as increased albumin concentration and radiation dose resulted in more consistent size control.

E3 ligase DECREASED GRAIN SIZE 1 promotes degradation of a G-protein subunit and positively regulates grain size in rice.

Grain size is one of the most important traits determining crop yield. However, the mechanism controlling grain size remains unclear. Here, we confirmed the E3 ligase activity of DECREASED GRAIN SIZE 1 (DGS1) in positive regulation of grain size in rice (Oryza sativa) suggested in a previous study. Rice G-protein subunit gamma 2 (RGG2), which negatively regulates grain size, was identified as an interacting protein of DGS1. Biochemical analysis suggested that DGS1 specifically interacts with canonical Gγ subunits (rice G-protein subunit gamma 1 [RGG1] and rice G-protein subunit gamma 2 [RGG2]) rather than non-canonical Gγ subunits (DENSE AND ERECT PANICLE 1 [DEP1], rice G-protein gamma subunit type C 2 [GCC2], GRAIN SIZE 3 [GS3]). We also identified the necessary domains for interaction between DGS1 and RGG2. As an E3 ligase, DGS1 ubiquitinated and degraded RGG2 via a proteasome pathway in several experiments. DGS1 also ubiquitinated RGG2 by its K140, K145 and S147 residues. Thus, this work identified a substrate of the E3 ligase DGS1 and elucidated the post transcriptional regulatory mechanism of the G-protein signalling pathway in the control of grain size.

Rational design of diblock copolymer enables efficient cytosolic protein delivery

Polymer-mediated cytosolic protein delivery demonstrates a promising strategy for the development of protein therapeutics. Here, we propose a new designed diblock copolymer which realizes efficient cytosolic protein delivery both in vitro and in vivo. The polymer contains one protein-binding block composed of phenylboronic acid (PBA) and N-(3-dimethylaminopropyl) (DMAP) pendant units for protein binding and endosomal escape, respectively, followed by the response to ATP enriched in the cytosol which triggers the protein release. The other block is PEG designed to improve particle size control and circulation in vivo. By optimizing the block composition, sequence and length of the copolymer, the optimal one (BP20) was identified with the binding block containing 20 units of both PBA and DMAP, randomly distributed along the chain. When mixed with proteins, the BP20 forms stable nanoparticles and mediates efficient cytosolic delivery of a wide range of proteins including enzymes, toxic proteins and CRISPR/Cas9 ribonucleoproteins (RNP), to various cell lines. The PEG block, especially when further modified with folic acid (FA), enables tumor-targeted delivery of Saporin in vivo, which significantly suppresses the tumor growth. Our results shall inspire the design of novel polymeric vehicles with robust capability for cytosolic protein delivery, which holds great potential for both biological research and therapeutic applications.

Layered magnesium vanadate film electrodes as high-performance cathode materials for thin-film non-aqueous zinc-ion batteries

Thin-film non-aqueous zinc-ion batteries (ZIBs) are recognized as an alternative energy storage technology with large-scale application prospects. The use of organic electrolytes with a wide window of electrochemical stability to construct non-aqueous ZIBs results in high operating voltage and energy density. In this paper, magnesium vanadate (Mg0.01V2O5) films were in situ grown and annealed on indium tin oxide (ITO) conductive glass using low-temperature liquid-phase deposition, and directly assembled into thin-film ZIBs. The battery achieved a stable capacity of 137.5 mA h m−2 after 80 cycles at 167 mA m−2. In addition, it exhibited an initial capacity of 104.1 mA h m−2 at 250 mA m−2 and a capacity retention of 75.6 % after 200 cycles. Good rate performance feedback was also obtained. According to X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), the electrochemical reaction process of the Mg0.01V2O5 film electrode was analyzed and the insertion/extraction mechanism of Zn2+ was investigated. Due to the instability of the V2O5 structure, the pre-inserted layer of Mg2+ plays a role as a pillar between layers during preparation, supporting the vanadium–oxygen layer and improving structural stability and battery life. At the same time, thin-film ZIB directly composed of film, diaphragm, electrolyte and zinc sheet has good diffusion dynamics, simplicity and size controllability, making it more suitable for commercial applications. Therefore, the thin-film non-aqueous ZIBs in this work may provide new ideas for mobile novel micro power sources.