Search Results (171)

This study investigates the influence of cerium nitrate (Ce(NO₃)₃·6H₂O) content on the performance of Ce(III)/CF/BN/EPN coatings intended for heat exchangers. A series of Ce(III)/carbon fibre (CF)/boron nitride (BN)/epoxy phenolic (EPN) coatings are fabricated with varying concentrations of Ce(NO₃)₃·6H₂O. The results of SEM and EDS show that the dissolution of cerium nitrate in acetone due to the particulate form causes it to be distributed in a diffuse state in the coating. This diffuse distribution does not significantly alter the porosity or structural morphology of the coating. With the increase in cerium nitrate content, both the EIS test results and mechanical damage tests indicate a progressive improvement in the corrosion resistance and self-healing properties of the coatings, while the thermal conductivity (TC) remains largely unaffected. The Ce in the coating reacts with the water molecules penetrating into the coating to generate Ce₂O₃ and CeO₂ with protective properties to fill the permeable pores inside the coating or to form a passivation film at the damaged metal–coating interface, which enhances the anticorrosive and self-repairing properties of the coating. However, the incorporation of Ce(NO₃)₃·6H₂O does not change the distribution structure of the filler inside the coating. As a result, the phonon propagation path, rate, and distance remain unchanged, leading to negligible variation in the thermal conductivity. Therefore, at a cerium nitrate content of 2.5 wt%, the coating exhibits the best overall performance, characterised by a |Z|_0.1Hz value of 6.08 × 10⁹ Ω·cm² and a thermal conductivity of approximately 1.4 W/(m·K). Full article

Micro-nano bubbles (MNBs) are tiny bubbles with diameters ranging from 200 nm to 30 µm. They possess unique physicochemical properties such as a large specific surface area, slow rising velocity, high gas dissolution rate, high mass transfer efficiency, and strong interfacial zeta potential. These properties endow MNBs with great potential in various fields, including water treatment, enhanced oil recovery, medical and health care, and agriculture. This paper systematically reviews the physicochemical properties, generation methods, and applications of micro-nano bubbles. The main production methods include the mechanical stirring, pressurized dissolved gas release, ultrasonic cavitation, venturi injection, electrolysis, etc. The principles, advantages and disadvantages, and optimization strategies of these methods are comprehensively analyzed. In terms of applications, the mechanisms and typical cases of MNBs in enhanced oil recovery, water treatment, mineral flotation, medical drug delivery, and crop yield enhancement are thoroughly discussed. Extensive research has shown that MNB technology is highly efficient, energy-saving, and environmentally friendly. However, improving bubble stability, generation efficiency, and large-scale application remain key directions for future research. Full article

Carbonate rock slopes in reservoir environments are increasingly exposed to dissolution-induced deterioration due to water level fluctuations. However, the influence of internal structures—particularly calcite veins—on dissolution behavior remains inadequately understood. The acid-induced dissolution of limestone by a sulfuric acid solution leads to the removal of soluble minerals and changes to the rock structure. Natural variation in rock structures—particularly in the presence, density, and morphology of calcite veins—can significantly affect the dissolution process and its outcomes. In this study, we obtained three types of Triassic limestone from the same host rock but with varying vein structures from the Three Gorges Reservoir area. Cylindrical rock specimens were prepared to investigate the acid-induced dissolution behavior of limestone in a sulfuric acid solution. We identified and analyzed the macrostructures on the rock specimens before and after the interaction. Additionally, SEM was employed to observe the microstructures of the specimens before and after the acid-induced dissolution, and fractal dimension analysis was conducted on the SEM images to quantify surface complexity. Furthermore, we used a focused ion beam–scanning electron microscope (FIB-SEM) with an automatic mineral identification and characterization system, as well as mineral roundness calculation, for mineral identification and analysis. Based on the experiments and analyses, we determined the following: The contact surfaces between the host rock and the calcite veins increase the dissolution areas between the limestone and the sulfuric acid solution, intensifying the dissolution reactions, enhancing the connectivity of the original microstructural planes, and generating new, highly extended dissolution fissures. The calcite veins facilitate the entry of sulfuric acid solution into the limestone, intensifying the dissolution of the edges and corners of dolomite and resulting in the gradual rounding of dolomite shapes. Quantitatively, the limestone with dense, fine calcite veins exhibited the most severe dissolution, with water absorption rates nearly twice as high as the non-veined samples (0.13% vs. 0.07%), a 2.2% reduction in fractal dimension, and a 19.53% increase in dolomite roundness with the 1 ≤ R ≤ 3 interval, indicating significantly enhanced surface complexity and mineral reshaping. In summary, the presence of more calcite veins, regardless of their width, leads to more severe rock dissolution. Full article

Background/Objectives: Proteolysis-targeting chimeras (PROTACs) have shown significant potential in the treatment of intractable diseases. However, their clinical applications are limited by poor water solubility and permeability. In this study, the cyclodextrin inclusion method was employed for the first time to prepare the PROTAC-CD complex with the aim of improving the dissolution of a PROTAC drug (LC001). Methods: Initially, sulfobutyl ether-β-cyclodextrin (SBE-β-CD) was selected to improve the solubility of LC001. The polymer TPGS was screened based on the phase solubility method to enhance the efficiency of complexation and solubilization capacity, and its ratio with SBE-β-CD was optimized. The ternary complex was prepared by lyophilization with an SBE-β-CD/TPGS molar ratio of 1:0.03. Differential scanning calorimetry, powder X-ray diffraction, and scanning electron microscopy results confirmed the formation of an amorphous complex. Fourier-transform infrared and molecular docking simulations indicated the formation of hydrogen bond interactions between components. Results: The results showed that the ternary complexes significantly improved the dissolution rate and release amount of LC001 in PBS (pH 6.8) and were unaffected by changes in gastric pH compared to the binary complexes and physical mixtures. The lack of crystal structure in the lyophilized particles and the formation of nano aggregates in solution may be the reasons for the improved dissolution of the ternary complex. Conclusions: In conclusion, the addition of TPGS to the LC001-SBE-β-CD binary system has a synergistic effect on improving the solubility and dissolution of LC001. This ternary complex is a promising formulation for enhancing the dissolution of LC001. Full article

Aiming at the problem that conventional friction reducers used in fracturing cannot simultaneously possess properties such as temperature resistance, salt resistance, shear resistance, rapid dissolution, and low damage. Under the design concept of “medium-low molecular weight, salt-resistant functional monomer, supramolecular physical crosslinking aggregation, and enhanced chain mechanical strength”, acrylamide, sulfonic acid salt-resistant monomer 2-acrylamide-2-methylpropanesulfonic acid, hydrophobic association monomer, and rigid skeleton functional monomer acryloyl morpholine were introduced into the friction reducer molecular chain by free radical polymerization, and combined with the compound suspension technology to develop a new type of multi-functional viscous friction reducer suspension (SAMD), the comprehensive performance of SAMD was investigated. The results indicated that the critical micelle concentration of SAMD was 0.33 wt%, SAMD could be dissolved in 80,000 mg/L brine within 3.0 min, and the viscosity loss of 0.5 wt% SAMD solution was 24.1% after 10 min of dissolution in 80,000 mg/L brine compared with that in deionized water, the drag reduction rate of 0.1 wt% SAMD solution could exceed 70% at 120 °C and still maintained good drag reduction performance in brine with a salinity of 100,000 mg/L. After three cycles of 170 s⁻¹ and 1022 s⁻¹ variable shear, the SAMD solution restored viscosity quickly and exhibited good shear resistance. The Tan δ (a parameter characterizing the viscoelasticity of the system) of 1.0 wt% SAMD solution was 0.52, which showed a good sand-carrying capacity, and the proppant settling velocity in it could be as low as 0.147 mm/s at 120 °C, achieving the function of high drag reduction at low concentrations and strong sand transportation at high concentrations. The viscosity of 1.4 wt% SAMD was 95.5 mPa s after shearing for 120 min at 140 °C and at 170 s⁻¹. After breaking a gel, the SAMD solution system had a core permeability harm rate of less than 15%, while the SAMD solution also possessed the performance of enhancing oil recovery. Compared with common friction reducers, SAMD simultaneously possessed the properties of temperature resistance, salt resistance, shear resistance, rapid dissolution, low damage, and enhanced oil recovery. Therefore, the use of this multi-effect friction reducer is suitable for the development of unconventional oil reservoirs with a temperature lower than 140 °C and a salinity of less than 100,000 mg/L. Full article

The characteristics of marine–continental transitional shale reservoirs and the performance parameters of fracturing fluids, such as pH and mineralization, play a crucial role in influencing the flowback efficiency of these fluids. Excessive retention of fracturing fluids within the reservoir can lead to a significant decrease in permeability, thereby diminishing gas well productivity. This study investigates shale samples sourced from the marine–continental transitional shale formation in the eastern Ordos Basin, along with field-collected fracturing fluid samples, including formation water, sub-formation water, distilled water, inorganic acids, and organic acids, through flowback experiments. The results show that: (1) the flowback rate of shale fracturing fluids exhibits a positive correlation with salinity, with low-salinity fluids showing a dual effect on clay mineral hydration. These fluids increase the pore volume of the sample from 0.003 cm³/g to 0.0037 cm³/g but also potentially reduce permeability by 31.15% to 99.96%; (2) the dissolution effects of inorganic and organic acids in the fracturing fluids enhance the flowback rate by 16.42% to 22.25%, owing to their chemical interactions with mineral constituents; (3) in the development of shale gas reservoirs, it is imperative to carefully devise reservoir protection strategies that balance the fracture-inducing effects of clay mineral hydration and expansion, while mitigating water sensitivity damage. The application of acid preflush, primarily including inorganic or organic acids, in conjunction with the advanced fracturing techniques, can enhance the connectivity of shale pores and fractures, thereby improving fracture conductivity, increasing the flowback rate of fracturing fluids, and ensuring sustained and high gas production from wells. Full article

Improving the stability of drugs in the solid state, as well as improving their solubility and poor bioavailability, is highly physiologically relevant. In this study, we focused on enhancing the solubility of hypoxanthine (HYP) through salt formation resulting from the preparation of hypoxanthine–maleic acid salt (HYP-MAL). Single crystals were obtained through solvent evaporation methods, and DSC, TGA, PXRD, FT-IR, and ¹H NMR spectra were used to characterize the samples. The salt system had higher solubility properties than HYP, with an equilibrium solubility in water that was roughly 2.4 times greater than that of HYP, but the salt’s equilibrium solubility increased when the pH shifted from 7.4 to 1.2; additionally, from 0 to 10 min, the powder dissolution rate was 1.8 times that of HYP, resulting in increased bioavailability. The anti-obesity impact of HYP-MAL salt on obese mice was investigated, providing important insights for the development of future weight-loss medications. Full article

Nitrate is the most prevalent inorganic pollutant in aquatic environments, posing a significant threat to human health and the ecological environment, especially in lakes and groundwater, which are located in the high agricultural activity intensity areas. In order to reveal the sources of nitrogen pollution in lakes and groundwater, this study of the transformation mechanism of nitrogen in the interaction zone between lakes and groundwater has become an important foundation for pollution prevention and control. The coupling effect between the biogeochemical processes of nitrate and iron has been pointed out to be widely present in various water environments in recent years. However, the impact of iron minerals on nitrate reduction in the lake–groundwater interaction zone of a high-salinity environment still remains uncertain. Based on the sediment and water chemistry characteristics of the Chagan Lake–groundwater interaction zone in northeastern China (groundwater TDS: 420~530 mg/L, Na⁺: 180~200 mg/L, and Cl⁻: 15~20 mg/L and lake water TDS: 470~500 mg/L, Na⁺: 210~240 mg/L, and Cl⁻: 71.40~87.09 mg/L), this study simulated relative oxidizing open system conditions and relative reducing closed conditions to investigate hematite and siderite effects on nitrate reduction and microbial behavior. The results indicated that both hematite and siderite promoted nitrate reduction in the closed system, whereas only siderite promoted nitrate reduction in the open system. Microbial community analysis indicated that iron minerals significantly promoted functional bacterial proliferation and restructured community composition by serving as electron donors/acceptors. In closed systems, hematite addition preferentially enriched Geobacter (denitrification, +15% abundance) and Burkholderiales (DNRA, +12% abundance), while in open systems, siderite addition fostered a distinct iron-carbon coupled metabolic network through Sphingomonas enrichment (+48% abundance), which secretes organic acids to enhance iron dissolution. These microbial shifts accelerated Fe(II)/Fe(III) cycling rates by 37% and achieved efficient nitrogen removal via combined denitrification and DNRA pathways. Notably, the open system with siderite amendment demonstrated the highest nitrate removal efficiency (80.6%). This study reveals that iron minerals play a critical role in regulating microbial metabolic pathways within salinized lake–groundwater interfaces, thereby influencing nitrogen biogeochemical cycling through microbially mediated iron redox processes. Full article

This study aims to develop and evaluate pH-sensitive food packaging films, based on starch and enriched with aqueous wild blackberry extract (Rubus sp.). The extract was selected for its high anthocyanin content due to color changes in different pH environments. Extract analysis revealed a dry matter content of 23 mg/mL and a polyphenol concentration of 21.10 mg GAE/g (dry extract), with high antioxidant activity, measured to be an 86.57% DPPH radical neutralizer. Films were produced with wild blackberry extract at concentrations of 0%, 5%, 10%, and 15%. The analyses determined the barrier, mechanical, physical, and intelligent properties of biodegradable films. The introduction of the extract resulted in a substantial rise in water content (9.6–21.36%), swelling capacity (35.27–43.06%), dissolution rate in water (288.05–459.89%), and permeability to water vapor (1.99–3.69 × 10⁻¹⁰ g/(Pa × m × s)). The bioactive compounds in the extract enhanced the films’ antimicrobial and antioxidant properties, with the highest effectiveness observed in the film containing 15% extract. These starch-based films, enriched with aqueous wild blackberry extract, demonstrated strong potential for packaging foods prone to pH changes during fermentation, such as fruits, dairy products, meat, and fish. Full article

This study systematically investigates the heterogeneity of the Chang 6 reservoir in the Wuqi–Dingbian region of the Ordos Basin through integrated petrographic analysis using scanning electron microscopy (SEM), thin-section petrography, and mercury intrusion porosimetry. The results reveal that this feldspathic sandstone reservoir exhibits significant compositional and textural variations controlled by depositional environments. Dingbian samples displayed elevated feldspar (avg. 42.3%), lithic fragments (18.1%), and carbonate cementation (15.7%), accompanied by intense mechanical compaction and cementation processes. Pore systems in Dingbian were dominated by residual intergranular pores (58–62% of total porosity) and secondary dissolution pores. In contrast, Wuqi reservoirs demonstrated superior pore connectivity through well-developed intergranular pores (65–72%), grain boundary pores, and microfracture networks. Pore throat characterization revealed distinct architectural patterns: Wuqi exhibited broad bimodal/multimodal distributions (0.1–50 μm) with 35–40% macro-throat (>10 μm) contribution to flow capacity, while Dingbian showed narrow unimodal distributions (1–10 μm) with <15% macro-throat participation. These microstructural divergences fundamentally governed contrasting production behaviors. Wuqi wells achieved higher initial flow rates (15–20 m³/d) with 60–70% water cut, yet maintained stable production through effective displacement systems enabled by dominant macropores. Conversely, Dingbian wells produced lower yields (5–8 m³/d) with 75–85% water cut, experiencing rapid 30–40% initial declines that transitioned to prolonged low-rate production phases. This petrophysical framework provides critical insights for optimized development strategies in heterogeneous tight sandstone reservoirs, particularly regarding water management and enhanced oil recovery potential. Full article

The solubility behavior of drugs is a critical factor in formulation development. Approximately 40–45% of new drugs face market entry challenges due to low water solubility. Enhancing drug bioavailability is thus essential in developing pharmaceutical dosage forms. Many biopharmaceutical class II and IV drugs are commonly prescribed to treat inflammations, infections, and pain from various pathologies. Their oral administration has several drawbacks, including significant first-pass liver effects, low bioavailability, and adverse gastrointestinal effects. Topical application has gained relevance due to its advantages in delivering drugs directly to the target site, avoiding gastrointestinal irritation, and increasing their effectiveness. However, topical hydrogel formulations with poorly water-soluble drugs face challenges related to the skin’s permeability. Therefore, preparing topical hydrogels using solid dispersions (SDs) is an effective strategy to enhance the dissolution rate of poorly soluble drugs, thereby improving their topical bioavailability. In this review, the concepts of SDs, topical delivery systems, and topical hydrogel formulations incorporating SDs, as well as their preparation methods, characterization, and applications, will be discussed. Full article

Background: Formulating poorly water-soluble drugs poses significant challenges due to their limited solubility and bioavailability. Loratadine (LTD), classified as a BCS II molecule, exhibits notably low solubility, leading to reduced bioavailability. Objective: This study aims to enhance the dissolution rate of LTD through the utilization of the wet granulation process using Tocopheryl polyethylene glycol 1000 succinate (TPGS). Methods: A Design-of-Experiment methodology was adopted to investigate and optimize the formulation variables for preparing an oral delivery system of LTD with improved dissolution properties. The levels of TPGS (2–6% w/w), as a surfactant, and sodium starch glycolate (SSG; 2–8% w/w), as a super-disintegrant, were established as independent variables in the formulations. Loratadine was granulated in the presence of TPGS, and the resultant granules were subsequently compressed into tablets. The granules and tablets produced were then subjected to characterization. Results: ANOVA analysis indicated that both TPGS and SSG had a significant (p < 0.05) influence on the critical characteristics of the obtained granules and tablets, with TPGS showing a particularly notable effect. The optimal concentrations of TPGS and SSG for the development of LTD tablets with the necessary quality attributes were identified as 5.0% w/w and 2.0% w/w, respectively, through optimization utilizing the desirability function. The tablets produced at these optimized concentrations displayed favorable properties concerning their mechanical strength (5.72 ± 0.32 KP), disintegration time (7.11 ± 1.08 min.), and release profile (86.21 ± 1.61%). Conclusions: In conclusion, incorporating TPGS in the granulation process shows promise in improving the dissolution profile of poorly water-soluble drugs and demonstrated formulation robustness. Full article

In this study, cellulose nanocrystals (CNs) were utilized to enhance the mechanical properties and sulfate corrosion resistance of engineered cementitious composites (ECCs). The results of compressive strength and uniaxial tensile tests demonstrated that the incorporation of CNs significantly improved the compressive strength, strain rate, tensile strength, and sulfate corrosion resistance of ECC specimens. Scanning electron microscopy (SEM) observations revealed that the addition of CNs facilitated the formation of increased amounts of ettringite and calcium silicate hydrate (C-S-H) in the matrix, enhancing the hydration degree of the cementitious system and increasing the overall density of the ECC structure. Molecular dynamics simulations were employed to investigate the interactions between CN, C-S-H, water molecules, and sulfate ions (SO₄²⁻) while also calculating the kinetic parameters of atoms at the interface. These simulations provided insights into the microstructural strengthening mechanism of CNs in improving the sulfate corrosion resistance of ECCs. The results indicated that CNs adsorb onto C-S-H via Ca-O and H-O coordination, forming a protective layer that inhibits the penetration of SO₄²⁻ and water molecules into the C-S-H structure. Additionally, CNs form hydrogen bonds with SO₄²⁻ and water molecules, which restricts their diffusion and reduces their coordination with the C-S-H interface and the dissolution of SO₄²⁻ and water to the hydration product, thereby enhancing the sulfate corrosion resistance of ECCs. Full article

Cannabidiol (CBD) has demonstrated therapeutic potential in treating epilepsy, multiple sclerosis, Alzheimer’s, Parkinson’s, and Crohn’s diseases. Despite its promising effects and analgesic, anti-inflammatory, and anxiolytic properties, oral CBD’s full potential is hindered by poor water solubility (0.7–10 μg/mL), low permeability, and chemical instability. This study aimed to enhance CBD’s dissolution, stability, and gastrointestinal (GI) permeability by forming a CBD–phospholipid complex (CBD-PLC). We hypothesised that CBD-PLC would enhance CBD’s hydrophilicity, thus improving GI barrier permeability. This study involved screening an optimal phospholipid (PL) using a Design of Experiments (DoE) approach to prepare CBD-PLC with nanosized droplets (194.3 nm). Dissolution studies revealed significantly enhanced release rates for CBD-PLC—44.7% at 2 h and 67.1% at 3 h—compared to 0% for pure CBD and 7.2% for a physical mixture (PM). Cellular uptake studies showed that at 30 µM, CBD-PLC exhibited 32.7% higher apparent permeability coefficients (P_app), nearly doubling at 40 µM compared to pure CBD. Cytotoxicity tests confirmed safety over 24 h, while 12-month stability tests demonstrated consistent performance under varied conditions. The results indicate that CBD-PLC improves CBD’s solubility, permeability, and stability, offering a promising strategy to address the limitations of oral CBD delivery systems. Full article

The source of sulfate in the groundwater of karst springs in the northern Taihang Mountains remains unclear due to the influence of multiple factors. To investigate this, 33 sampling points were selected in August 2022 across the exposed, covered, and buried areas of the spring basin, and water samples were collected. Hydrochemistry and sulfur–oxygen dual isotope methods were employed to examine the distribution characteristics of sulfate, δ¹⁸O_SO4, and δ³⁴S_SO4. Based on the distinct characteristics of sulfur isotopes from different sources, the sources of sulfate in various environments were qualitatively analyzed. Additionally, the contribution rates of each source were quantitatively determined using a Bayesian stable isotope mixing model. The results showed that the sulfate content in karst groundwater ranged from 16.68 to 156.84 mg/L, with an average of 62.22 mg/L, and indicated an increasing trend from exposed to covered to buried areas. The δ³⁴S_SO4 values in karst groundwater ranged from 3.1‰ to 13.5‰, with an average of 6.49‰, while the δ¹⁸O_SO4 values ranged from 2.9‰ to 10.3‰, with an average of 5.49‰. The δ³⁴S_SO4 values showed a general increasing trend across the exposed, covered, and buried areas, whereas the δ¹⁸O_SO4 values remained relatively stable across these areas. The analysis revealed that the primary sulfate sources in the exposed area were atmospheric precipitation, soil sulfate, chemical fertilizer, and sewage, contributing 19.6%, 63.5%, 9.4%, and 7.5%, respectively. In the covered area, the main sources were atmospheric precipitation, sulfide oxidation, soil sulfate, and gypsum dissolution, with contributions of 16.5%, 58.7%, 15.9%, and 8.9%, respectively. In the buried area, the sulfate primary originated from atmospheric precipitation, sulfide oxidation, and gypsum dissolution, contributing 11.6%, 78.5%, and 9.9%, respectively. This study provides critical insights into the sulfate sources in different environments, enhancing the understanding of groundwater sulfate pollution in the study area. These findings provide a scientific foundation for managing groundwater pollutants and resources in the karst regions of northern China. Full article