Interplay between Kinetics and Thermodynamics on the Probability Nucleation Rate of a Urea–Water Crystallization System

In this contribution, by employing the Poisson distribution combined with the regular solution theory in the classical nucleation theory (CNT) framework, we construct a new model to uncover the relationship between induction time (<i>t</i>_ind) and supercooling (Δ<i>T</i>) and saturation temperature (<i>T</i>₀) at different specific probabilities. By choosing the urea aqueous solution as a benchmark system, we show that the value of ln­(1/<i>t</i>_ind) follows a reasonable linear relationship with (<i>T</i>₀/Δ<i>T</i>)²/(<i>T</i>₀ – Δ<i>T</i>), except the probability value tends to be 0 or 1. Furthermore, we also shed new light on the role of chemical potential difference and nucleation temperature in determining the nucleation rate; namely, although the chemical potential difference is the driving force for the crystallization process, it does not always favor the nucleation process. We demonstrated that when the chemical potential difference increases as the nucleation temperature decreases (Δ<i>T</i> gradually increases), in this case, the kinetic factor overwhelms the thermodynamic factor thus leading to a faster nucleation rate by employing the CNT theory. However, when the chemical potential difference decreases as the nucleation temperature increases, we found that increasing the nucleation temperature favors the nucleation process both in kinetic and thermodynamic aspects

Three-Dimensional Macroporous TiO₂‑MXene Nanostructure-Based Films for Flexible Freestanding Sulfur Cathodes

Flexible freestanding electrodes with high energy density and good cycling stability are of great importance for wearable devices. Lithium–sulfur battery is considered a promising next-generation energy storage system owing to its high theoretical energy density and low production cost. However, several issues such as the severe polysulfide shuttle effect, poor electrical conductivity, and drastic volume change of sulfur cathodes hindered the commercialization of lithium–sulfur batteries. To solve these problems, many recent studies have focused on a class of two-dimensional (2D) MXene nanomaterials with abundant surface functional groups and excellent mechanical flexibility. Although these unique MXene nanomaterials have chemical affinity and are easily designed into various nanostructures, the inevitable overlap of the nanosheets can impair their electrochemical performance. Herein, we develop a three-dimensional (3D) macroporous TiO2-MXene nanostructure-based film for the flexible freestanding sulfur cathode in this paper. Such structure can realize a dual-confined strategy for polysulfides, that is, physical barrier and chemical absorption. The hollow porous MXene nanostructure can physically inhibit the polysulfide shuttle effect. And the TiO2 nanoparticles on the surface of MXene can effectively anchor and catalyze polysulfides in the electrochemical reaction. Moreover, the 3D conductive MXene network can provide fast electronic pathways, which promote the electrochemical reaction and reduce the electrochemical polarization. Without adding additional binders and conductive agents, the 3D macroporous TiO2-MXene freestanding nanostructure-based film S@TiO2-Ti3C2Ox shows good electrochemical performances with a specific capacity of 1022.7 and 523.7 mAh/g at 0.1 and 1C, respectively. This work provides a possible application of lithium–sulfur batteries in the field of flexible electronic devices

Luminescence Anisotropy and Thermal Effect of Magnetic and Electric Dipole Transitions of Cr³⁺ Ions in Yb:YAG Transparent Ceramic

In this article, we present an in-depth optical study on luminescence spectral features and the thermal effect of the magnetic dipole (MD) transitions (e.g., the R lines of ²E → ⁴A₂) and the associated electric dipole transitions (e.g., phonon-induced sidebands of the R lines) of Cr³⁺ ions in ytterbium–yttrium aluminum garnet polycrystalline transparent ceramic. The doubly split R lines predominately due to the doublet splitting of the ²E level of the Cr³⁺ ion in an octahedral crystal field are found to show a very large anisotropy in both emission intensity and thermal broadening. The large departure from the intensity equality between them could be interpreted in terms of large difference in coupling strength with phonons for the doubly split states of the ²E level. For the large anisotropy in thermal broadening, very different effective Debye temperatures for the two split states may be responsible for it. Besides the ²E excited state, the higher excited states, for example, ⁴T₁ and ⁴T₂ of the Cr³⁺ ion, also exhibit a very large inequality in coupling strength with phonons at room temperature. By examining the Stokes phonon sidebands of the MD R lines at low temperatures with the existing ion–phonon coupling theory, we reveal that they indeed carry fundamental information of phonons. For example, their broad background primarily reflects Debye density of states of acoustic phonons. These new results significantly enrich our existing understanding on interesting but challenging luminescence mechanisms of ion–phonon coupling systems

Novel Strategy to Control Polymorph Nucleation of Gamma Pyrazinamide by Preferred Intermolecular Interactions during Heterogeneous Nucleation

Pyrazinamide is usually nucleated from solution as a dimeric form; it has rarely been reported in the γ form (chain structure) crystallized from solution, especially from aqueous solution. Here, we designed a novel way to obtain the γ form of pyrazinamide from aqueous solution. Specific templates were applied to disturb the intrinsic self-association of pyrazinamide molecules and prevent the formation of the dimer structure. In this paper, the heterosynthon design method was applied in pyrazinamide heterogeneous nucleation, in which sulfonamides were chosen as the templates. In the presence of sulfonamide templates, hydrogen bonds between the carbonyl moiety of the amide group in pyrazinamide molecules and the sulfonamide moiety of sulfonamide template molecules were formed; these preferred intermolecular interactions protected the carbonyl groups of PZA, facilitating assembly of PZA molecules in a chain via N–H···N′ and nucleating as the γ form of PZA. This is the first time that the heterosynthon design method was applied to screen effective templates, which can control and select the desired polymorph in heterogeneous nucleation

Simultaneous temperature and particle size measurement of burning iron particles using a single color camera

Iron powder is recognized as a promising clean energy carrier and a recyclable metal fuel due to its high energy density and carbon-free nature. Research focusing on single iron particles is essential for understanding the combustion characteristics and mechanisms of iron powder, as well as for designing reliable iron-fueled combustors. Temperature and particle size, as key parameters of burning iron particles, are typically measured using optical diagnostic methods. However, low-cost simultaneous measurement methods for the temperature and particle size of burning iron particles are scarce. This study introduces a method employing a single RGB camera to simultaneously measure the temperature and particle size of burning iron particles, validated by a heated thermocouple. Particle size is measured by the intensity of Blue channel based on light attenuation approach, and temperature is measured by the intensity ratio of Red/Green channels based on black-body radiation law. Statistical analyses of the temperature and particle size of iron particles at four different heights above the burner were conducted. Along the heights, the average particle size and temperature of the iron particles generally increase, except at a height of 50 mm, where more iron particles entering the cooling phase lead to a slight decrease in average temperature. The conditional probability density functions of temperature and particle size indicate a statistical dependence between the particle size and temperature of iron particles that larger particle sizes typically correspond to higher temperatures. The results confirm that the simultaneous measurement method is a cost-effective, high-accuracy tool for characterizing the combustion behavior of iron particles.</p

DataSheet1_Modified Baihu decoction therapeutically remodels gut microbiota to inhibit acute gouty arthritis.PDF

Background: Acute gouty arthritis (AGA) is the most common first symptom of gout, and the development of gout as a metabolic and immune inflammatory disease is also correlated with the gut microbiota. However, the mechanism of the effect of changes in the gut microbiota on AGA remains unclear. The intestinal flora can not only affect purine metabolism or regulate inflammation, but also influence the therapeutic effect of drugs on AGA. The aim of this study was to investigate the exact mechanism of modified Baihu decoction (MBD) in the treatment of AGA and whether it is related to the regulation of the structure of the intestinal flora.Methods: On the 21st day of MBD administration by continuous gavage, a rat acute gouty arthritis model was constructed using sodium urate (0.1 mL/rat, 50 mg/mL), and the ankle joint swelling was measured before and 4 h, 8 h, 24 h, and 48 h after the injection of sodium urate. After 48 h of sodium urate injection, serum, liver, kidney, ankle synovial tissue and feces were collected from rats. The collected samples were examined and analyzed using H&E, Elisa, Immunohistochemistry, Histopathology, 16S rDNA, and Biochemical analysis. To investigate the mechanism of MBD to alleviate AGA using pro-inflammatory factors and intestinal flora.Results: MBD (5.84, 35 g/kg) was administered orally to AGA rats and diclofenac sodium tablets (DS-tablets) were used as standard treatment control. Serum biochemical assessment confirmed that MBD is a safe drug for the treatment of AGA. In addition, our findings confirmed that MBD relieved AGA-related symptoms, such as toe swelling. Lowering serum levels of uric acid, IL-1β, and TGF-β1 immunohistochemical results also confirmed that MBD reduced the expression of inflammatory elements such as IL-1β, NLRP3, ASC, and Caspase-1 in synovial tissue.Furthermore, compared with control group, the 16s rDNA sequencing of AGA rat faeces revealed an increase in the relative abundance of Lachnospiraceae, Muribaculaceae, and Bifidobacteriaceae species. While the relative abundance of Lactobacillaceae, Erysipelotrichaceae, Ruminococcaceae, Prevotellaceae and Enterobacteriaceae showed a relative decrease in species abundance. Of these, the reduction in species abundance of Enterobacteriaceae was associated with a reduction in amino acid metabolism and environmental perception. After MBD therapeutic intervention, the disturbance of the intestinal flora caused by AGA was restored.Conclusion: In summary, MBD is an effective agent for the treatment of AGA, with the potential mechanism being the regulation of intestinal flora to control inflammation. This would help to promote the therapeutic effect of MBD on AGA.</p

Image2_Modified Baihu decoction therapeutically remodels gut microbiota to inhibit acute gouty arthritis.TIF

Background: Acute gouty arthritis (AGA) is the most common first symptom of gout, and the development of gout as a metabolic and immune inflammatory disease is also correlated with the gut microbiota. However, the mechanism of the effect of changes in the gut microbiota on AGA remains unclear. The intestinal flora can not only affect purine metabolism or regulate inflammation, but also influence the therapeutic effect of drugs on AGA. The aim of this study was to investigate the exact mechanism of modified Baihu decoction (MBD) in the treatment of AGA and whether it is related to the regulation of the structure of the intestinal flora.Methods: On the 21st day of MBD administration by continuous gavage, a rat acute gouty arthritis model was constructed using sodium urate (0.1 mL/rat, 50 mg/mL), and the ankle joint swelling was measured before and 4 h, 8 h, 24 h, and 48 h after the injection of sodium urate. After 48 h of sodium urate injection, serum, liver, kidney, ankle synovial tissue and feces were collected from rats. The collected samples were examined and analyzed using H&E, Elisa, Immunohistochemistry, Histopathology, 16S rDNA, and Biochemical analysis. To investigate the mechanism of MBD to alleviate AGA using pro-inflammatory factors and intestinal flora.Results: MBD (5.84, 35 g/kg) was administered orally to AGA rats and diclofenac sodium tablets (DS-tablets) were used as standard treatment control. Serum biochemical assessment confirmed that MBD is a safe drug for the treatment of AGA. In addition, our findings confirmed that MBD relieved AGA-related symptoms, such as toe swelling. Lowering serum levels of uric acid, IL-1β, and TGF-β1 immunohistochemical results also confirmed that MBD reduced the expression of inflammatory elements such as IL-1β, NLRP3, ASC, and Caspase-1 in synovial tissue.Furthermore, compared with control group, the 16s rDNA sequencing of AGA rat faeces revealed an increase in the relative abundance of Lachnospiraceae, Muribaculaceae, and Bifidobacteriaceae species. While the relative abundance of Lactobacillaceae, Erysipelotrichaceae, Ruminococcaceae, Prevotellaceae and Enterobacteriaceae showed a relative decrease in species abundance. Of these, the reduction in species abundance of Enterobacteriaceae was associated with a reduction in amino acid metabolism and environmental perception. After MBD therapeutic intervention, the disturbance of the intestinal flora caused by AGA was restored.Conclusion: In summary, MBD is an effective agent for the treatment of AGA, with the potential mechanism being the regulation of intestinal flora to control inflammation. This would help to promote the therapeutic effect of MBD on AGA.</p

Image1_Modified Baihu decoction therapeutically remodels gut microbiota to inhibit acute gouty arthritis.PNG

Background: Acute gouty arthritis (AGA) is the most common first symptom of gout, and the development of gout as a metabolic and immune inflammatory disease is also correlated with the gut microbiota. However, the mechanism of the effect of changes in the gut microbiota on AGA remains unclear. The intestinal flora can not only affect purine metabolism or regulate inflammation, but also influence the therapeutic effect of drugs on AGA. The aim of this study was to investigate the exact mechanism of modified Baihu decoction (MBD) in the treatment of AGA and whether it is related to the regulation of the structure of the intestinal flora.Methods: On the 21st day of MBD administration by continuous gavage, a rat acute gouty arthritis model was constructed using sodium urate (0.1 mL/rat, 50 mg/mL), and the ankle joint swelling was measured before and 4 h, 8 h, 24 h, and 48 h after the injection of sodium urate. After 48 h of sodium urate injection, serum, liver, kidney, ankle synovial tissue and feces were collected from rats. The collected samples were examined and analyzed using H&E, Elisa, Immunohistochemistry, Histopathology, 16S rDNA, and Biochemical analysis. To investigate the mechanism of MBD to alleviate AGA using pro-inflammatory factors and intestinal flora.Results: MBD (5.84, 35 g/kg) was administered orally to AGA rats and diclofenac sodium tablets (DS-tablets) were used as standard treatment control. Serum biochemical assessment confirmed that MBD is a safe drug for the treatment of AGA. In addition, our findings confirmed that MBD relieved AGA-related symptoms, such as toe swelling. Lowering serum levels of uric acid, IL-1β, and TGF-β1 immunohistochemical results also confirmed that MBD reduced the expression of inflammatory elements such as IL-1β, NLRP3, ASC, and Caspase-1 in synovial tissue.Furthermore, compared with control group, the 16s rDNA sequencing of AGA rat faeces revealed an increase in the relative abundance of Lachnospiraceae, Muribaculaceae, and Bifidobacteriaceae species. While the relative abundance of Lactobacillaceae, Erysipelotrichaceae, Ruminococcaceae, Prevotellaceae and Enterobacteriaceae showed a relative decrease in species abundance. Of these, the reduction in species abundance of Enterobacteriaceae was associated with a reduction in amino acid metabolism and environmental perception. After MBD therapeutic intervention, the disturbance of the intestinal flora caused by AGA was restored.Conclusion: In summary, MBD is an effective agent for the treatment of AGA, with the potential mechanism being the regulation of intestinal flora to control inflammation. This would help to promote the therapeutic effect of MBD on AGA.</p

Measurement and Correlation of the Solubility of Pyrimethanil in Seven Monosolvents and Two Different Binary Mixed Solvents

The solubility of pyrimethanil in two binary solvents (water + methanol and water + ethanol) and seven monosolvents (methanol, ethanol, <i>n</i>-propanol, isopropanol, <i>n</i>-butanol, isobutanol, and cyclohexane) was measured by a gravimetric method within the temperature range of 283.15 to 323.15 K at atmospheric pressure. In the investigated temperature range, the solubility of pyrimethanil in all monosolvents or mixed solvents increases with increasing temperature. The solubility in the monosolvents was well-correlated using the NRTL model, the Apelblat model, and the Wilson model. Furthermore, the NRTL model and the modified version of the Jouyban–Acree model (the Apel-JA equation) were employed to correlate the solubility in binary solvents. The results showed that these models have a satisfactory correlation. When we measured the solubility, we found that the solvent has a great influence on the crystal habit. Therefore, these results can give guidance for practical industrial processes such as the design of the crystallization process and control of the crystal morphology

Solvent-Mediated Nonoriented Self-Aggregation Transformation: A Case Study of Gabapentin

A good powder performance is one of the essential targets for gabapentin (GBP). However, the low bulk density and flowability of GBP are still the industrial problems in practical production. The main purpose of this paper is to investigate the phase transformation of GBP from form I to form II in methanol, ethanol, propanol, acetone, acetonitrile, and ethyl acetate and improve the powder properties. The results suggested that there are two kinds of phase transformation mechanisms of GBP. One is the classic solvent-mediated transformation in alcohols, and the other is the solvent-mediated nonoriented self-aggregation transformation in other solvents, which is proposed for the first time. On account of the low water activity and solubility, there is a self-cleaving phenomenon caused by the dehydration in the form I particles, and then the unstable phase transforms into form II, but the growth of the stable form is confined by the size and shape of the initial metastable particle and the products are aggregates. These aggregates with a well-defined shape and size have good performance in the dissolution rate with improved bioavailability