Search Results (437)

Background/Objectives: Cyclodextrin-based ternary systems are widely used to improve the solubility of poorly soluble drugs. Amino acids such as L-arginine may further increase dissolved drug concentrations and reduce precipitation under physiologically relevant conditions. In many systems, apparent solubility enhancement is influenced simultaneously by drug ionization, inclusion complex formation, multicomponent interactions, and solid–liquid equilibria. This study presents a physicochemical modeling approach for analyzing pH-dependent solubility enhancement and precipitation behavior in drug–cyclodextrin–L-arginine systems. Methods: The model combines acid–base equilibria, binary inclusion complexation, ternary association, and explicit solid-phase partitioning within a unified mass-balance treatment. The approach was applied to representative ternary systems containing repaglinide, sulfadiazine, cefixime, and meloxicam. Results: Quantitative comparison with published phase-solubility data for the repaglinide–HPβCD–L-arginine system confirmed the numerical consistency of the model. The calculated profiles showed that enhanced solubilization and reduced precipitation occur only within specific pH regions determined by coupled equilibrium effects. For cefixime and meloxicam, the calculations were interpreted as predictive applications because directly comparable validation datasets were not available. Outside the favorable pH regions, a substantial fraction of the drug remained in the solid phase. Conclusions: These observations support the importance of pH and multicomponent interactions in controlling formulation performance in cyclodextrin-containing systems. The obtained profiles may support preliminary optimization of formulation pH and excipient composition before experimental screening. Full article

Calcium (Ca²⁺) and magnesium (Mg²⁺) are essential divalent cations whose homeostasis is essential for cardiovascular, muscular and metabolic function. Absolute or relative imbalances between Ca and Mg can lead to cardiovascular, metabolic and neurological pathologies. Ionized calcium (Ca²⁺) is a biologically active fraction of plasma calcium that is tightly regulated by protein binding, phosphate complexation, magnesium modulation and acid–base status. Ionized calcium plays a central role in multiple physiological processes and is strongly influenced by plasma pH, phosphate concentration and magnesium levels. However, the combined effects of these parameters are difficult to evaluate intuitively because of their nonlinear interactions. In this study, a numerical simulation framework was used to explore how simultaneous variations in pH, phosphate and magnesium may influence ionized calcium under typical physiological plasma conditions as a phenomenological framework linking ionic equilibrium with viscosity-dependent flow parameters under well-mixed plasma conditions. The simulations reveal phenomenological changes in which concurrent increases in pH and phosphate or reductions in magnesium produce disproportionately large decreases in ionized calcium. Within the physiological ranges examined, the results also indicate a region of relative stability for ionized calcium corresponding to Ca/Mg ratios close to 3, while this value should be interpreted as an emergent feature of the modeled parameter space rather than a universal physiological constant. These findings illustrate the importance of considering multiple electrolyte interactions simultaneously when evaluating calcium homeostasis and may provide a conceptual framework for further experimental investigation. Full article

Aiming at non-uniformity in the vertical direction in the polishing effect on stainless steel after plasma electrolytic polishing (PEP), this paper took 304 L stainless steel as the research object. Under an ammonium sulfate electrolyte system with a mass fraction of 2.5 wt%, PEP was carried out utilizing different placement methods for the anode and electrolyte temperatures, and the causes of non-uniformity in the polishing process were explored. Experimental results demonstrate that the vertical polishing inhomogeneity originates from the upward movement of unruptured bubbles at the sample bottom. Under the combined effects of electrolyte internal pressure and bubble buoyancy, a vapor-gas envelope (VGE) featuring a thick upper part and thin lower part forms near the sample surface. This enhances plasma-related physicochemical reactions at the sample bottom and consequently raises the polishing rate. The vertical polishing unevenness can be alleviated by adjusting the electrolyte temperature. Non-uniformity could be improved by controlling the temperature of the electrolyte. Compared with the result at 95 °C, the maximum dimensional variation in each region on the sample at 75 °C was reduced by 36% because a VGE with more uniform thickness was formed, and a properly oxidized sparse layer helped protect the substrate from ablation and over-polishing. In addition, the removal rate of elements on the surface of stainless steel is affected by its activity due to the oxidation reaction. The high removal amount in the bottom region caused a trend of increasing Cr and decreasing Fe content percentages from the top to the bottom on the stainless-steel surface. However, the oxidation removal rate of elements is extremely fast due to the high temperature of the ionization center and strong electric field; therefore, the content percentage of each element on the surface is little changed after polishing. Full article

This study presents a systematic terahertz time-domain spectroscopy (THz-TDS) investigation of hardened cement paste, framed as a complex-optical measurement in which the real and imaginary parts of the response probe distinct microstructural attributes. Transmission-mode measurements were made on pastes with water-to-cement (w/c) ratios of 0.3, 0.4, and 0.5 at curing ages of 7, 14, 28, and 56 days. The effective refractive index, obtained from the time-domain pulse delay (7, 28, and 56 days, paired with mercury intrusion porosimetry), correlates strongly and linearly with porosity over nine porosity-paired conditions spanning 15.1–30.4% (pooled R² = 0.94, p < 0.001). In a quasi-static effective-medium framework—where the pores a re far smaller than the THz wavelength—this reflects the dependence of the effective permittivity on the solid volume fraction: the Bruggeman model outperforms the Maxwell–Garnett model, and all data fall within the Wiener bounds, lying close to the upper bound, indicating a continuously connected solid matrix with isolated pores. Cross-validated porosity estimation is reliable to within about ±2 percentage points (refractive-index uncertainty ±0.02–0.04). The absorption follows a power law (β ≈ 1.0–1.3) characteristic of disorder-activated vibrational absorption, in which the loss of long-range order in the amorphous C–S–H relaxes the crystalline selection rules and couples the THz field to the full vibrational density of states. The refractive index (structure-sensitive, governed by volume fraction) and the absorption (material-sensitive, governed by solid disorder; estimated loss tangent of order 0.1) thus form two complementary channels. Combining the THz-derived porosity with the Powers hydration model gives a degree of hydration consistent with literature ranges—an indirect comparison rather than direct validation. These results establish THz-TDS as a non-contact, non-ionizing technique for rapid porosity estimation and hydration assessment of cementitious materials. Full article

To investigate the rheological properties and compositional changes in SBS-modified bitumen under different aging conditions in the unique environmental conditions of the Xinjiang region, this study selected a local 70# base bitumen from Xinjiang and prepared modified bitumen by adding 4.0%, 4.5%, and 5.0% SBS modifier, respectively. RTFOT and PAV were used to simulate the short-term thermal-oxidative aging and long-term oxidative pressure aging processes of the bitumen samples, respectively. The three key indicators and dynamic rheological properties of the bitumen were tested for the original sample, as well as before and after short-term thermal-oxidative aging and long-term oxidative pressure aging. Thin-layer chromatography/flame ionization detection (TLC/FID) was used to analyze the migration patterns of the samples’ chemical components, and a random forest model was employed to establish a quantitative mapping between the four components of the modified bitumen and the rutting factor over a wide temperature range. The results indicate that aging weakens the improvement effect of SBS on the high-temperature performance of bitumen. However, 4.5% SBS-modified bitumen subjected to long-term oxidative pressure aging still maintains the best high- and low-temperature performance, elastic recovery capacity, and fatigue resistance compared to other dosage levels. It also has the highest bitumen content, which verifies the high-temperature performance of this dosage at the component level. Therefore, the optimal SBS dosage is recommended to be 4.5%. Notably, as the SBS content increases, it significantly regulates the increase in heavy fraction content during the aging process, while the decrease in light fraction content is not significantly affected by the content. Based on the random forest algorithm, a mapping relationship between fractions and properties under fully aged conditions was established. This study provides a theoretical basis for research on the modification and aging mechanisms of Xinjiang bitumen. Full article

Background: The Ejection Fraction (EF) represents a fundamental pillar for the phenotypic classification and clinical management of cardiovascular diseases. Although trans-thoracic echocardiography (TTE) acts as the first-line examination and cardiac magnetic resonance (CMR) is the reference gold standard, cardiac computed tomography (CCT) has undergone a technological evolution. The advent of wide-detector scanners and artificial intelligence (AI) models has enabled CCT to transition from a purely morphological tool to a modality capable of comprehensive, three-dimensional morpho-functional assessments. Methods: This narrative review evaluates the literature across Scopus, MEDLINE, and Web of Science regarding the calculation of biventricular function and EF using CCT. It provides an updated summary of current clinical applications, technological advancements, and comparative diagnostic reliability against TTE and CMR. Results: The CCT “one-stop-shop” concept allows for the simultaneous acquisition of anatomical data and systolic function metrics (EDV, ESV, SV, EF), optimizing clinical workflows at no additional cost. Being intrinsically three-dimensional, CCT bypasses the geometric assumptions and apical foreshortening artifacts typical of 2D-TTE, demonstrating high volumetric concordance with CMR. Nevertheless, structural limitations persist, primarily regarding ionizing radiation exposure, contrast media toxicity, dependence on heart rhythm stability, and lower temporal resolution compared to CMR. Conclusions: EF determination via CCT has achieved technical maturity and clinical validation. While it does not intend to replace TTE or CMR, it offers synergistic data when integrated with primary anatomical indications. Furthermore, AI integration has been shown to potentially automate this workflow, transforming CCT into an opportunistic screening tool for subclinical cardiac dysfunction. Full article

The accumulation of un-ionized ammonia (NH₃) during the transport of live ornamental fish poses a critical threat to animal welfare and post-transport survival. This study evaluated the efficacy of calcium alginate-encapsulated native Amazonian microalgae, Ankistrodesmus sp., Chlorella sp., Scenedesmus sp., and Synechococcus sp., for NH₃ bioremediation during a 15-day simulated transport of female Poecilia reticulata. Biometric endpoints were selected using a four-criterion framework, identifying specific growth rate by weight (SGRW), specific growth rate by length (SGRL), and Fulton’s condition factor (K) as essential non-redundant parameters. Time-weighted average (TWA) NH₃ served as the primary dose variable for four-parameter log-logistic modeling fitted to biological replicate means (n = 15). Ankistrodesmus sp. and Scenedesmus sp. maintained 97.8% survival and restricted TWA NH₃ to 0.036 and 0.047 mg/L, respectively, whereas the empty capsule control reached 6.7% survival and 0.150 mg/L TWA NH₃. Kruskal–Wallis tests on biological replicate means confirmed significant treatment effects on all biometric endpoints (SGRW: H(4) = 13.50, ε² = 0.950; SGRL: H(4) = 13.50, ε² = 0.95; p < 0.01). Chronic EC₅₀ values of 0.10505 mg/L NH₃ (SGRW; Adj-R² = 0.828) and 0.09967 mg/L NH₃ (SGRL; Adj-R² = 0.812) were established, representing approximately 7.8% and 7.4% of the female-specific acute LC₅₀ (1.34 mg/L NH₃), respectively, yielding chronic-to-acute ratios of approximately 13 for both growth endpoints and confirming that sublethal growth impairment precedes lethality. Partial disruption of the calcium alginate capsule matrix was observed from day 5 onward; the relative contributions of encapsulated and free-cell fractions were not quantified. Under the experimental conditions tested, 15-day simulated transport of female P. reticulata under controlled illumination and without feeding, calcium alginate-encapsulated Ankistrodesmus sp. and Scenedesmus sp. treatments represent effective, scalable, and residue-free alternatives to chemical ammonium neutralization for comparable ornamental fish transport scenarios; extension to dark commercial air transport or other species requires further experimental validation. Full article

Obesity is a major global health burden that is linked to type 2 diabetes, cardiovascular disease, and metabolic syndrome. Chitosan oligosaccharides (COS) are bioactive compounds that are derived from the depolymerization of the chitosan in crustacean shells and are promising candidates for natural anti-adipogenesis effects. However, there is incomplete understanding of the molecular mechanisms by which structurally defined low-molecular-weight COS modulates adipogenic transcription networks and global transcriptional reprogramming. MALDI-TOF (matrix-assisted laser desorption/ionization time-of-flight) mass spectrometry and ¹³C NMR spectroscopy indicated a predominance of dimeric species (DP2) at m/z 344.79, which represents a lower molecular weight fraction and is proposed to improve the membrane permeability and intracellular bioavailability of COS. In a 3T3-L1 preadipocyte model, COS treatment at concentrations of 320–1280 µg/mL dose-dependently reduced intracellular lipid accumulation, triglyceride content, and adipocyte maturation while enhancing lipolysis and insulin-mediated glucose uptake. Western blot analysis indicated dose-dependent downregulation of PPARγ and C/EBPα. Transcriptomic RNA-seq analysis indicated large-scale transcriptional reprogramming with the altered expression of genes involved in PPAR signaling, PI3K-Akt, AMPK, insulin signaling, and fatty acid metabolism pathways among differentially expressed genes. These findings demonstrate that COS suppresses adipogenesis through the coordinated modulation of adipogenic transcription factors and multiple metabolic signaling pathways. The results support its potential as a promising natural compound but warrant preclinical investigation in the context of obesity and metabolic disorders. Full article

A study was conducted on the construction of sulfonated poly(aryl ether ketone) nanomicelles and their dispersion–displacement synergistic behavior in deep oil recovery. Unlike conventional surfactant systems, inorganic nanoparticle-based EOR materials, and polymeric nanofluids that mainly rely on interfacial tension reduction, wettability alteration, or viscosity regulation, this study constructs self-assembled sulfonated poly(aryl ether ketone) nanomicelles that integrate a rigid aromatic backbone, ionizable sulfonic acid groups, nanoscale dispersion, and interfacial regulation within one polymeric architecture. Sulfonated poly(aryl ether ketone) nanomicelles were prepared by combining polymer sulfonation with solvent-induced self-assembly, and their structural features, dispersion stability, interfacial behavior, porous-media transport, and displacement performance were systematically evaluated. Spectroscopic characterization confirmed the successful introduction of sulfonic acid groups into the polymer backbone. The resulting nanomicelles exhibited an average hydrodynamic diameter of 117.8 nm, a polydispersity index of 0.186, and a zeta potential of −38.6 mV in deionized water, while a value of −27.4 mV was still maintained at a salinity of 150,000 mg/L, indicating good electrostatic stability under highly mineralized conditions. Further evaluation showed that the 0.30 wt% system retained a transmittance of 97.4% after 15 d of static standing, and its particle size remained at 151.7 nm even under 120 °C and 150,000 mg/L, demonstrating favorable thermal–salinity tolerance. At the same concentration, the oil–water interfacial tension decreased to 6.9 mN/m at 1800 s, while the contact angle of oil-aged quartz was reduced from 118.4° to 58.7°, indicating effective regulation of both the oil–water interface and the solid surface wettability. During microscopic displacement, the residual oil area fraction decreased from 32.8% after water flooding to 14.6%, and cluster-like oil, corner oil, and film-like oil were reduced from 14.6%, 9.8%, and 8.4% to 5.9%, 4.2%, and 4.5%, respectively. In core flooding, the incremental oil recovery reached 13.2%, the final water cut decreased to 81.2%, and the injection pressure increased only from 0.42 MPa to 0.68 MPa. These results indicate that sulfonated poly(aryl ether ketone) nanomicelles promote deep residual-oil mobilization through the combined effects of stable dispersion, interfacial regulation, and effective transport, with 0.30 wt% identified as the preferred concentration range. The main scientific contribution of this work is to establish a structure–dispersion–interface–transport–displacement relationship for SPAEK nanomicelles under deep-reservoir conditions, providing a polymeric nanomicelle-based strategy distinct from conventional surfactant, sulfonated polymer, and nanoparticle flooding systems. Full article

Reduced graphene oxide (rGO) wrapped with poly(styrenesulfonate) (PSS) forms a stable hybrid material (rGO/PSS) capable of producing ultrathin films with promising barrier properties for Direct Methanol Fuel Cell (DMFC) applications. These films aim to mitigate methanol crossover, one of the major limitations of DMFC technology. In this work, we investigate the mechanisms underlying the methanol barrier effect of rGO/PSS, while maintaining water permeability. Classical Molecular Dynamics simulations were employed to explore the structural and dynamic properties of rGO/PSS at different polymer ionization fractions in a solvent mixture of water, methanol, and hydronium. The influence of the sulfonation fraction on film self-assembly was analyzed, including its impact on PSS conformation, rGO sheet distribution, and PSS–rGO interactions. Finally, the effect of the rGO/PSS structure on solvent diffusion was investigated, and the mechanisms responsible for the selective transport of methanol were elucidated. Full article

Gamma irradiation serves as a robust platform for the structural diversification of natural compounds, utilizing high-energy reactions with free radicals to generate novel scaffolds with improved biological properties. In present study, p-coumaric acid was exposed to ionizing radiation at various doses to induce molecular transformations. Significant degradation of the precursor was confirmed at a dose of 60 kGy, which provided the optimal range for the generation of radiolysis products. The chromatographic fraction of the resulting mixture afforded two novel derivatives, 1 and 2, along with a known analog 3. Comprehensive spectroscopic characterization assigned their structures as (3R,4R)-3-hydroxymethyl-4-(4-hydroxyphenyl)-dihydrofuran-2(3H)one (1), (3R*,4S*)-3-hydroxymethyl-4-(4-hydroxyphenyl)-dihydrofuran-2(3H)-one (2), and (4S)-4-(4-hydroxyphenyl)-dihydrofuran-2(3H)-one (3). The anti-inflammatory effects of the isolates were evaluated using lipopolysaccharide-stimulated RAW264.7 macrophages. While neither the parent compound p-coumaric acid nor its derivatives exhibited significant cytotoxicity at concentrations up to 40 μM, their anti-inflammatory potencies varied significantly. Notably, compound 1 exhibited potent inhibitory effects on pro-inflammatory signaling, significantly inhibiting the production of TNF-α, IL-6, and IL-12p70, surpassing the bioactivity of the parent compound. Compound 2 displayed a similar, attenuated inhibitory trend, suppressing the secretion of TNF-α and IL-12p70. Compound 3 modulated the immune response by promoting anti-inflammatory cytokine IL-10 production, despite an inconsistent suppressive effect on pro-inflammatory cytokines. These results suggest that gamma-induced radiolysis is a useful strategy for enhancing the therapeutic potential of dietary phenolic compounds. Full article

Ambrosia arborescens Mill., a native medicinal plant traditionally used in the Andean region, has a poorly characterized essential oil (EO), with no prior reports on its anticholinesterase or antioxidant potential. As a first report and preliminary screening study, this work characterizes the chemical composition of the EO and evaluates its acetylcholinesterase (AChE) inhibitory and antioxidant activities. The EO was isolated by hydrodistillation and analyzed using gas chromatography coupled with mass spectrometry (GC–MS) and flame ionization detection (GC-FID). The biological activities were evaluated using the Ellman method to determine AChE inhibition and using ABTS and DPPH assays to determine antioxidant activity. Analysis of the chemical composition revealed 31 compounds, and the major components were γ-curcumene (28.63%), trans-muurola-4(14),5-diene (27.85%), and eucavone (18.46%). The EO showed moderate AChE inhibitory activity, with an IC₅₀ value of 28.04 ± 1.02 µg/mL, and limited antioxidant activity, with ABTS SC₅₀ = 373.75 ± 1.30 µg/mL and DPPH SC₅₀ = 1101.84 ± 1.63 µg/mL. These findings demonstrate that the EO possesses selective anticholinesterase activity and limited antioxidant capacity. Given the structural diversity of its constituents, the observed bioactivity is likely the result of the combined contributions of multiple components; however, the specific active constituents and potential synergistic interactions require further investigation through bioassay-guided fractionation. These findings represent the first preliminary screening of the biological activities of A. arborescens EO and provide a foundation for future bioactivity-guided investigations. Full article

This study examines the impact of alkaline treatment on hydrogels composed of acrylic acid (AAc), sodium alginate (SA), and poly(ethylene oxide) (PEO), produced via 5.5 MeV electron beam irradiation, emphasizing swelling behavior and functional performance. Hydrogels were treated with NaOH (0.25 M and 0.50 M) to modulate biodegradability, water retention capacity, and water retention ratio. The materials were characterized in terms of structural, morphological, thermal, and physicochemical properties using FTIR, SEM, and TGA/DSC, along with evaluations of gel fraction, cross-linking density, mesh size, porosity, swelling kinetics, and water retention. FTIR confirmed carboxyl group ionization and polymer chain reorganization, while SEM revealed structural changes, rougher surfaces, and larger pores that facilitate water uptake. Thermal stability of the hydrogels increased, with the T-onset rising from 236 °C in the untreated samples to 451 °C after alkaline treatment. Treatment with 0.25 M NaOH enhanced mesh size (127.97 ± 4.05 nm), porosity (99.74 ± 0.05%), and swelling capacity (428 ± 14 g/g), whereas 0.50 M induced partial degradation and reduced swelling. Despite a significant increase in degradability (>39.49 ± 1.94% after 28 days), treated hydrogels maintained functional performance, showing accelerated water uptake and improved rainwater retention. Overall, alkaline treatment enables tunable structural and functional modifications, optimizing hydrogel performance for agricultural water management. Full article

Background: Magnesium regulates neuronal excitability, NMDA receptor activity, and cerebrovascular tone. Dysmagnesemia is common in patients with acute brain injury (>65%), yet large randomized trials of magnesium neuroprotection have been neutral despite strong physiological rationale and consistent observational associations with outcomes. A key limitation may be diagnostic misclassification: the total serum magnesium poorly reflects the biologically active ionized fraction and may misclassify magnesium status in 20–85% of ICU patients during critical illness. Purpose: This narrative review synthesizes current evidence on magnesium physiology, measurement limitations, and clinical implications in neurocritical care. Overview: We discuss the mechanisms of magnesium depletion, outline the conceptual “two-hit” model (chronic deficiency plus acute ICU losses), and highlight the potential value of ionized magnesium for improved patient evaluation. Emerging syndrome-specific data suggest that magnesium disturbances are associated with prognostic signals. Improved phenotyping may help explain prior trial neutrality and support stratified approaches to magnesium monitoring and repletion. Future studies should evaluate magnesium-guided strategies and phenotype-driven trials to clarify the therapeutic role of magnesium in neurocritical care. Full article

To address the growing demand for sustainable road infrastructure development and resolve technical bottlenecks in reclaimed asphalt pavement (RAP) recycling, this study optimized the performance of recycled asphalt mixtures (RAMs) and validated their engineering applicability for field construction. RAM specimens were prepared using 5-year and 10-year aged RAP from Ningxia, with a constant RAP content of 30%. Laboratory tests including high-temperature rutting, moisture susceptibility, low-temperature cracking, dynamic modulus, and four-point bending fatigue were performed to determine the optimal mix proportion. Fourier Transform Infrared Spectroscopy (FTIR) and Thin-Layer Chromatography-Flame Ionization Detection (TLC-FID) were employed to reveal the regeneration mechanism of waste engine oil (WEO). Results showed that WEO modified the functional groups and four fractions of asphalt, optimizing its colloidal structure, while excessive WEO compromised high-temperature stability. The optimal WEO contents were 4% for RAP (5Y) and 8% for RAP (10Y), which significantly enhanced the overall performance of RAM to adapt to Ningxia’s climate. This study provides technical support for sustainable road infrastructure in arid and semi-arid regions. Full article