Solubility In Aqueous Solutions Research Articles

Estimation of hydrogen solubility in aqueous solutions using machine learning techniques for hydrogen storage in deep saline aquifers

The porous underground structures have recently attracted researchers’ attention for hydrogen gas storage due to their high storage capacity. One of the challenges in storing hydrogen gas in aqueous solutions is estimating its solubility in water. In this study, after collecting experimental data from previous research and eliminating four outliers, nine machine learning methods were developed to estimate the solubility of hydrogen in water. To optimize the parameters used in model construction, a Bayesian optimization algorithm was employed. By examining error functions and plots, the LSBoost method with R² = 0.9997 and RMSE = 4.18E-03 was identified as the most accurate method. Additionally, artificial neural network, CatBoost, Extra trees, Gaussian process regression, bagged trees, regression trees, support vector machines, and linear regression methods had R² values of 0.9925, 0.9907, 0.9906, 0.9867, 0.9866, 0.9808, 0.9464, and 0.7682 and RMSE values of 2.13E-02, 2.43E-02, 2.44E-02, 2.83E-02, 2.85E-02, 3.40E-02, 5.68E-02, and 1.18E-01, respectively. Subsequently, residual error plots were generated, indicating the accurate performance of the LSBoost model across all ranges. The maximum residual error was − 0.0252, and only 4 data points were estimated with an error greater than ± 0.01. A kernel density estimation (KDE) plot for residual errors showed no specific bias in the models except for the linear regression model. To investigate the impact of temperature, pressure, and salinity parameters on the model outputs, the Pearson correlation coefficients for the LSBoost model were calculated, showing that pressure, temperature, and salinity had values of 0.8188, 0.1008, and − 0.5506, respectively, indicating that pressure had the strongest direct relationship, while salinity had an inverse relationship with hydrogen solubility. Considering the results of this research, the LSBoost method, alongside approaches like state equations, can be applied in real-world scenarios for underground hydrogen storage. The findings of this study can help in a better understanding of hydrogen solubility in aqueous solutions, aiding in the optimization of underground hydrogen storage systems.

B-211 Quantum dot-DNA nanocomposite enhanced single-molecule flow (SiM-Flow) for ultrasensitive microRNA detection in metastatic castrate-resistant prostate cancer

Abstract Background MicroRNAs (miRs) like miR-375 and miR-1290 are associated with cancer progression and chemoresistance in metastatic castrate-resistant prostate cancer (mCRPC). However, these prognostic biomarkers are typically present in low abundance (0.1∼1 fM) in patient plasma, which is close to the detection limit of the current gold standard techniques, quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR). Therefore, we tested a nanomaterial that incorporates quantum dots (QDs) and DNA amplicons for enhanced in-solution counting applications in plasma from a cohort of mCRPC patients. The QD-DNA nanocomposite increases the fluorescent intensity of an individual amplicon for ultrasensitive flow-counting and provides higher multiplex capacity due to the narrow emission band of QD for simple instrumentation. Methods QDs were synthesized with spectrally distinct emission bands by tuning the size or composition of CdSe core. QDs were then coated with multidentate polymer allowing further bioconjugations and better solubility in aqueous solution. The oligonucleotides complementary to amplicons generated from selected miR targets (prognostic biomarkers: miR-1290 and miR-375; normalization biomarkers: miR-16, miR-30a-5p, and cel-39) were then conjugated to QDs with optimized ratio. Total RNA was extracted from a screening cohort of 14 mCRPC patients from Huntsman Cancer Institute where platelet-poor plasma was uniformly processed with exogenous spike-in, cel-39, added in. qRT-PCR was performed using TaqMan miRNA assays, and SiM-Flow was conducted using a commercial flow cytometry to count QD barcoded enzymatic-extended miRs nanoparticles. The DNA template used for extending miRs was designed by our lab and purchased from IDT-DNA. Pearson correlation and interclass agreement analysis were applied to evaluate the concordance between the two assays. The mCRPC cohort was followed for clinical outcomes, and survival analysis for the time of progression from mCRPC to death/last follow-up was performed to determine the prognostic value of the QD-DNA nanoparticle counts. The Cox proportional hazards model was applied to linearly incorporate multiple hazard factors of patients for multivariate survival analysis. Results We demonstrated the multiplex ability of QDs with less than 5% false positive rate. The machine learning-guided optimized assay shows a 1000-time improved limit of detection of assay compared to the published literature. Interclass agreement > 0.9 and Pearson correlation of 0.94 between SiM-Flow and RT-qPCR on human plasma extracts suggest high specificity of SiM-Flow on miR detection. Also, miR-375 was identified among all the samples through SiM-Flow, although it was unidentified by qRT-PCR in 14 samples. Higher levels of miR-1290, miR-375, and prostate-specific antigen were significantly associated with poor overall survival (p=0.019) in the initial survival analysis. Survival analysis replication is ongoing in an independent mCRPC cohort. Conclusions SiM-Flow was able to detect target miRs in mCRPC patients’ plasma with a high agreement with qRT-PCR and lower detection limit and demonstrated multiplex ability with a simple optical set-up. This shows technological advancement in the detection of cancer-associated biomarkers and will aid in precision medicine therapeutic and point-of-care applications with both prognostic and predictive potential.

Low-melting mixture solvents as novel solubilizing agents: Improving tolvaptan formulation and therapeutic efficacy

Presently, a significant number of pharmaceutical drugs exhibit poor solubility in water and fall within categories II and IV of the biopharmaceutical classification system. This predicament has prompted the exploration for novel solvents or excipients to enhance the solubility and bioavailability of the active compounds in aqueous environments. Low-melting mixture solvents (LoMMSs) have gained recognition as potential solvents for active pharmaceutical ingredients to improve therapeutic efficacy and delivery. This study focuses on the preparation of a eutectic mixture composed of betaine, malic acid, proline, and water (BE-MA-PR-WA) to enhance the formulation options for tolvaptan, an FDA-approved medication used to treat acute congestive heart failure, which has limited solubility in aqueous solutions. The findings presented in this article represent the first reported results on the administration of LoMMS-solubilized tolvaptan. Furthermore, an examination of the solubility and bioavailability of tolvaptan utilizing this mixture was conducted, alongside an assessment of its toxicity. The solubility of tolvaptan in BE-MA-PR-WA (1:1:1:7) increased 483 times compared to solubility in water. Toxicity studies indicated that the LoMMS formulation BE-MA-PR-WA was safe for oral administration. The oral bioavailability of tolvaptan was significantly increased by 1.9-fold in the BE-MA-PR-WA than that in water. In addition, the 5-hour urine volume of rats indicated that BE-MA-PR-WA also enhanced the diuretic effects of tolvaptan in rats. The findings suggest that BE-MA-PR-WA enhance the solubility and bioavailability of tolvaptan, and are deemed non-toxic. Consequently, LoMMS may be deemed promising solubilizing agents, potentially facilitating the absorption of poorly bioavailable medications.

19F MRI/CEUS Dual Imaging-Guided Sonodynamic Therapy Enhances Immune Checkpoint Blockade in Triple-Negative Breast Cancer.

Treatment of highly aggressive triple-negative breast cancer (TNBC) in the clinic is challenging. Here, a liposome nanodrug (LP@PFH@HMME) integrating imaging agents and therapeutic agents for bimodal imaging-guided sonodynamic therapy (SDT) is developed, which boosted immunogenicity to enable potent immunotherapy via immune checkpoint blockade (ICB) in TNBC. In the acidic tumor microenvironment (TME), LP@PFH@HMME undergoes "nano-to-micro" transformation due to a pH-responsive lipid fusion, which makes droplets much more sensitive to ultrasound (US) in contrast-enhanced ultrasound (CEUS) and SDT studies. The nanodrug demonstrates robust bimodal imaging ability through fluorine-19 magnetic resonance imaging (19F MRI) and CEUS bimodal imaging, and it exhibits excellent solubility in aqueous solution with relatively high 19F content and desirable long transverse relaxation time (T2 = 1.072 s), making it suitable for high-performance 19F MRI, in addition to effective accumulation of nanodrugs after tail vein injection. Thus, 19F MRI/CEUS dual imaging is achievable to show adequate time points for US irradiation of tumor sites to induce highly effective SDT, which produces abundant reactive oxygen species (ROS) triggering immunogenic cell death (ICD) to assist ICB-based immunotherapy. The combination treatment design of sonodynamic therapy with immunotherapy effectively inhibited TNBC growth and recurrence, highlighting the promise of multifunctional nanodrugs in treating TNBC.

Solid-phase synthesis of amphiphilic cyclic peptides as a surfactin mimetic

The cyclic lipopeptide surfactin, an anionic biosurfactant, has received increased interest owing to its unique characteristics and promising applications. Although surfactin is known to exhibit distinctive surface activities and self-assembly ability, the role of the cyclic peptide moiety in its physico-chemical properties requires further investigation. Here, we report the solid-phase peptide synthesis of surfactin mimics such as cyclic heptapeptides with the same amino acid sequence as surfactin (CSF) and cyclic octapeptides with dodecyl chains (CSF12). The structure–property relationships of the cyclic peptides were then examined. The acidic forms of CSF and CSF12 were poorly soluble in water, but the addition of 1.5 or 2.0 equiv. of NaOH increased their solubility in aqueous solutions. The disodium salt of CSF (CSF-2Na) reduced the surface tension of water to 39.0 mN/m despite its absence of a long alkyl chain, indicating that the cyclic peptide moiety plays a crucial role in the surface activity of the surfactin mimic. In the case of the disodium salt of CSF12 (CSF12–2Na), the introduction of a dodecyl chain to the cyclic peptide moiety led to an increase in molecular orientation such that saturation at the air–water interface was observed. Thus, a long alkyl chain enhances the molecular assembly of the cyclic peptide at the air–water interface. The introduction of a long alkyl chain also enhanced the solubilisation of phospholipids. For instance, CSF12–1.5Na induced the solubilisation of L-α-dimyristoylphosphatidylcholine (DMPC) multilamellar vesicles in phosphate-buffered saline (PBS). These findings greatly contribute to the fundamental understanding of the broad spectrum of physico-chemical properties and biological activities of bio-derived cyclic peptides. Furthermore, these insights can also be helping design libraries for developing cyclic peptides for challenging therapeutics in skin disease or as cosmeceuticals to enhance skin appearance.

CO2 solubility in aqueous solution of salts: Experimental study and thermodynamic modelling

AbstractThere are many economic obstacles and complex engineering problems associated with CO2 capture and storage in saline aquifers that need to be addressed. Overcoming such challenges requires precise knowledge on the fluid phase equilibria of CO2‐brine systems. Having accurate CO2 solubility data over a wide range of temperature and pressure can greatly assist in resolving these obstacles by improving the performance and accuracy of the thermodynamic modeling and subsequent CCS engineering success.CO2 solubility in pure water and NaCl solutions has been widely studied in the literature, however, there is a lack of data on CO2 solubility at lower temperatures (below 298 K). Furthermore, limited phase equilibria data are available for CO2 solubility in CaCl2, MgCl2, and KCl solutions at elevated temperatures (i.e., T > 323.15 K).In this work, the phase equilibria of CO2 and brine systems are investigated experimentally and theoretically. In this study, solubilities of CO2 in pure water and various concentrations of NaCl (10, 15, 20, and 22 wt%), KCl (10, 15, and 22 wt%), CaCl2 (7.5, 10, 15.7, and 23.4 wt%), and MgCl2 (6.7, 11, 18, and 29 wt%) aqueous solutions are reported. All CO2 solubilities were measures at 323.15, 373.15, and 423.15 K and over various pressure ranges, while solubilities in 10 and 20 wt% NaCl aqueous solutions were also measured over the temperature range of 263 to 298 K and pressures up to the hydrate dissociation pressure of each system. Equation of state modelling using the PC‐SAFT and the Cubic Plus Association equations of state, is performed in the theoretical part of the study to validate the measured solubility data. © 2024 The Author(s). Greenhouse Gases: Science and Technology published by Society of Chemical Industry and John Wiley & Sons Ltd.

Printing amphotericin B on microneedles using matrix-assisted pulsed laser evaporation.

Transdermal delivery of amphotericin B, a pharmacological agent with activity against fungi and parasitic protozoa, is a challenge since amphotericin B exhibits poor solubility in aqueous solutions at physiologic pH values. In this study, we have used a laser-based printing approach known as matrix-assisted pulsed laser evaporation to print amphotericin B on the surfaces of polyglycolic acid microneedles that were prepared using a combination of injection molding and drawing lithography. In a modified agar disk diffusion assay, the amphotericin B-loaded microneedles showed concentration-dependent activity against the yeast Candida albicans. The results of this study suggest that matrix-assisted pulsed laser evaporation may be used to print amphotericin B and other drugs that have complex solubility issues on the surfaces of microneedles.

Near-infrared and multifunctional fluorescent probe enabled by cyanopyridine cyanine dye for bisulfite recognition and biological imaging

SO2 derivatives, sulfite/bisulfite, are widely employed in both the food processing and drug synthesis industries. Despite their widespread application, excessive levels of sulfite/bisulfite can negatively impact human health. Most probes for detecting sulfite/bisulfite are restricted by their fluorescence within the visible spectrum range and poor solubility in aqueous solution, which limit their use in food testing and biological imaging. Herein, a near-infrared probe comprising of the cyanopyridine cyanine skeleton, 4-((Z)−2-((E)−2-chloro-3-(2-cyano-2-(1-methylpyridine-4(1H)-ylidene)ethylidene)cyclohex-1-en-1-yl)−1-cyanovinyl)−1-methylpyridin-1-ium (abbreviated as CCP), was developed. This probe enables precise quantification of bisulfite (HSO3-) in almost pure buffered solutions, showing a near-infrared fluorescence emission at 784 nm with an impressively low detection limit of 0.32 μM. The probe stands out for its exceptional selectivity, minimal susceptibility to interference, and strong adaptability. The probe CCP utilizes the CC bond to trigger a near-infrared fluorescence quenching reaction with HSO3- via nucleophilic addition, which effectively disrupts the large delocalization within the molecule for accurate HSO3- identification. Moreover, the probe has been successfully applied in detecting HSO3- in various food products and living cells, simplifying the measurement of HSO3- content in water samples. This advancement not only enhances the analytical capabilities but also contributes to ensuring food safety and environmental protection. Environmental ImplicationSO2 derivatives including sulfite/bisulfite, serving dual roles as preservatives and antioxidants, have widespread application across various sectors including food preservation, water sanitation, and the pharmaceutical industry. Despite their widespread application, excessive levels of sulfite/bisulfite can affect human health. Developing methods for precisely and sensitively detecting sulfite/bisulfite in food products and biological samples is important for ensuring food safety and environmental protection. Here, a sensitive near-infrared and multifunctional fluorescent probe in a 99.9 % buffered solution, along with water gel encapsulation, has been successfully applied for the detection of bisulfite in food, authentic water samples, and biological cells.

Investigation on itraconazole solubility in aqueous solutions based on models, solvent effect, thermodynamic analysis and quantum chemical calculations

The mole-fraction solubility of itraconazole in four aqueous blends of ethanol/isopropanol/DMSO/methanol within the temperature range of 283.15 to 323.15 K was experimentally obtained using the isothermal shake-flask method. Under the identical temperature and ethanol/isopropanol/DMSO/methanol composition, itraconazole solubility in DMSO+water is much higher than that in ethanol/isopropanol/methanol + water. At the same temperature, the solubility increases monotonically with organic solvent concentration. X-ray power diffraction analysis demonstrated that over the course of the investigations, there was no crystal transition or solvate formation. The modified van’t Hoff-Jouyban-Acree and Jouyban-Acree models adequately related the solubility to solvent composition and temperature, with relative average deviations (RADs) not exceeding 7.65 %. Furthermore, the extended Hildebrand solubility approach was utilized to quantitatively characterize the solubility behavior at 298.15 K for the mixtures of ethanol/isopropanol/DMSO/methanol plus water. In both instances, the RADs were maintained below 4.12 %. The solubility parameter and dipolarity-polarizability of solutions have a major impact on the solubility fluctuation, as indicated by the analysis of the linear solvation energy relationship. The preferential solvation of itraconazole at 298.15 K was examined using the efficient approach of inverse Kirkwood-Buff integrals. The preferred solvation parameters showed positive values in blends within rich and moderate ethanol/isopropanol/DMSO/methanol composition regions. This suggests that the organic solvents preferentially solvated itraconazole. When itraconazole dissolved in the blends, thermodynamic analysis of the entropy-enthalpy compensation and dissolution parameters revealed both an endothermic and an enthalpy-driven mechanism. Furthermore, the microscopic electrostatic characteristics of basicity and acidity were effectively demonstrated by means of the electrostatic potential of molecular surface. The −C=O and −N=groups of the itraconazole molecule, which link the five-membered ring, are the primary targets of the electrophilic attack. An independent gradient model based on Hirshfeld partition analysis was used to demonstrate the weak interactions between itraconazole and solvents.

Anticancer activity of new water-soluble sulfonated thiosemicarbazone copper(II) complexes targeting disulfide isomerase

Copper complexes have shown promising anticancer properties, but they are often poorly soluble in aqueous solutions, thus limiting their possible medical developments and applications. We have recently isolated some copper(II) complexes with salicylaldehyde thiosemicarbazone ligands exhibiting remarkable nanomolar cytotoxic activity, but in vivo tests evidenced several difficulties related to their poor solubility. To overcome these limitations and increase solubility in aqueous solution, herein we report the synthetic strategy that led to the introduction of the sulfonic group on the ligands, then separated as salts (NaH2L1 - NaH2L5), as well as the synthesis and characterization of the related copper(II) complexes. The characterization of the complexes is completed by the analysis of the structures obtained by X-rays diffraction on single crystals on the species [Cu(HL5)(H2O)]2.2H2O, [Cu(HL2)(H2O)2].2H2O, and [Cu(HL1)(H2O]2.2H2O. While the uncoordinated ligands do not affect cancer cell viability, copper(II) complexes exhibit low to sub-micromolar cytotoxic activity, which is maintained in 3D (HCT-15 and 2008) spheroidal models of cancer cell. Notably, copper(II) complexes were selective towards cancer cells, showing high selectivity indexes. Investigations focused on elucidating the mechanism of action evidenced the protein disulfide-isomerase as an innovative molecular target for this class of water-soluble copper(II) complexes. Finally, preliminary in vivo experiments performed with the most representative derivative in the murine Lewis Lung Carcinoma, highlight its significant antitumor efficacy and better tolerability profile with respect to the reference metallodrug, suggesting for this sulfonated Cu(II) complex a potential clinical relevance.

Dispersion of Single-Walled Carbon Nanotubes by Aromatic Cyclic Schiff Bases via Non-Covalent Interactions.

One of the challenging issues that hinders the application of single-walled carbon nanotubes (SWCNTs) is the poor solubility and the inevitable formation of bundles. Efforts still need to be made towards solving the problem. Herein, we report a non-covalent strategy to disperse aggregated SWCNTs by aromatic cyclic Schiff bases assisted by ultrasonic techniques. The aromatic cyclic Schiff base (OMM) was synthesized via Schiff base reactions, and the molecular structure was determined by ATR-FT-IR, solid-state 13C-NMR, and HRMS. Although the yielded product showed poor solubility in aqueous solution and organic solvents, it could interact with and disperse the aggregated SWCNTs in dimethyl formamide (DMF) under the condition of ultrasound. UV-vis-NIR, FL, Raman spectra, AFM, and TEM, along with computer simulations, provide evidence for the interactions between OMM molecules and SWCNTs and the dispersion thereof. The semiconductive (7,5), (8,6), (12,1), and (9,7)-SWCNTs expressed a preference for dissolution. The capability of dispersion is contributed by π-π, C-H·π, and lone pair (lp)·π interactions between OMM and SWCNTs based on the simulated results. The present non-covalent strategy could provide inspiration for preparing organic cyclic compounds as dispersants for SWCNTs and then facilitate their further utilization.

Preparation, characterization and evaluation of HPβCD-PTX/PHB nanoparticles for pH-responsive, cytotoxic and apoptotic properties

Paclitaxel (PTX) is a potent anticancer drug. However, PTX exhibits extremely poor solubility in aqueous solution along with severe side effects. Therefore, in this study, an inclusion complex was prepared between PTX and hydroxypropyl-β-cyclodextrin (HPβCD) by solvent evaporation to enhance the drug's solubility. The HPβCD-PTX inclusion complex was then encapsulated in poly-3-hydroxybutyrate (PHB) to fabricate drug-loaded nanoparticles (HPβCD-PTX/PHB NPs) by nanoprecipitation. The HPβCD-PTX/PHB NPs depicted a higher release of PTX at pH 5.5 thus demonstrating a pH-dependent release profile. The cytotoxic properties of HPβCD-PTX/PHB NPs were tested against MCF-7, MDA-MB-231 and SW-620 cell lines. The cytotoxic potential of HPβCD-PTX/PHB NPs was 2.59-fold improved in MCF-7 cells in comparison to free PTX. Additionally, the HPβCD-PTX/PHB NPs improved the antimitotic (1.68-fold) and apoptotic (8.45-fold) effects of PTX in MCF-7 cells in comparison to PTX alone. In summary, these pH-responsive nanoparticles could be prospective carriers for enhancing the cytotoxic properties of PTX for the treatment of breast cancer.

Albumin-mediated molecular competition of supramolecular photosensitizers for NIR-II imaging-guided phototherapy

Heptamethine cyanines (Cy7) typically exhibit strong near-infrared (NIR) fluorescence signals when in monodisperse states, but their distinctive π-conjugated structure leads to limited solubility in aqueous solutions, ultimately resulting in inherent fluorescence self-quenching. Enhancing the fluorescence quantum yield of these agents within aqueous environments, in order to achieve high-resolution biological imaging, presents a significant challenge. Herein, a benzothiazole-based Cy7-derivative (Cy7-BTH) is developed, exhibiting unique H-aggregation properties in aqueous solutions. Bovine serum albumin (BSA) binds to Cy7-BTH (BSA@Cy7-BTH) to modulate its molecular stacking and energy transfer, boosting its fluorescence accompanied by bright NIR-II tail emission. The competitive binding alters the planarity of Cy7-BTH, restricting its intramolecular rotation, and simutaneously changes the conformation of BSA, leading to BSA@Cy7-BTH aggregation to form hierarchical-structured nanoparticles. Notably, the BSA@Cy7-BTH nanoparticles significantly enhanced photothermal response of Cy7-BTH while maintaining its controlled reactive oxygen species (ROS) generation, offering NIR-II imaging-guided surgical removal of primary tumors, and simultaneously inhibiting cancer cell metastasis by synergistic PDT/PTT dissection of metastatic tumor cells in sentinel lymph nodes (SLNs). This study provides an innovative but facile strategy for their potential clinical applications by precisely regulating the intermolecular competitive interactions of NIR theranostic agents.

The development of ternary and quaternary solid dispersion based hydrotropic blends of atorvastatin calcium

Background and objective: Atorvastatin calcium (ATV) has a solubility in aqueous solutions of greater than 0.1 mg/ml to less than 1 mg/ml, which is very slightly soluble. When developing dosage forms for these medications, formulation scientists still face challenges. This study's goal was to use various hydrotropic agents in the formation of solid dispersion-based hydrotropic blends to improve the solubility properties of atorvastatin calcium. Methods: In this study, twenty-two distinct binary, ternary, and quaternary formulations of ATV were prepared by employing five different hydrotropic agents and combining at least two hydrotropic agents in concentrations of 10% and 20% (w/v). Moreover, solid dispersion by the solvent evaporation method and physical mixture-based hydrotropic blends in the ratio of (1:2) have been formulated. The produced formulations were characterized using an FTIR analysis. Results: According to the findings, binary formulations containing 20% (w/v) concentrations of sodium benzoate (SB), sodium salicylate (SS), and resorcinol (R) enhanced the solubility ratio of ATV by 439.31, 689.57, and 106.21 folds, respectively. Furthermore, ternary formulations (FT14) and quaternary formulations (FQ18) resulted in the enhancement of ATV solubility by 938.45 and 995.12 folds, respectively. Ternary solid dispersion demonstrated the highest enhancement in solubility ratio by 87.68 folds and resulted in a higher dissolution rate of ATV than pure samples of the drug. Finally, FTIR analyses excluded any interactions between medications and excipients by showing no noticeable shift in the peaks. Conclusion: Solid dispersion based hydrotropic blends can provide the production of the dosage forms of practically insoluble drugs with a favorable enhancement ratio in solubility.

Development of heat-assisted in-situ solvent formation liquid phase microextraction followed by derivatization for the simultaneous extraction of aliphatic amines from wastewater samples prior to gas chromatography-mass spectrometry

Herein, a cost-effective, rapid, and selective liquid phase microextraction procedure has been developed for the extraction of some aliphatic amines from sewage samples. The method was based on in-situ formation of chloroform as an extraction solvent into the sample solution followed by derivatization by butylchloroformate prior to gas chromatography- mass spectrometry. Chloroform is formed by the reaction of chloral hydrate and sodium hydroxide. The extraction procedure was accelerated by heating. Also heating decreases chloroform solubility in aqueous solution. To improve the analytical signals, derivatization of the analytes is done by butylchloroformate. The effect of major parameters on the extraction efficiency were studied and optimized. Under the optimized conditions, enrichment factor and extraction recovery were in the ranges of 259–296 and 78–89 %, respectively. Low limits of detection (0.08–0.12 ng mL−1) and quantification (0.28–0.41 ng mL−1), wide linear ranges, and relative standard deviations less than 6 % for intra −and inter-day precisions were acceptable. Lastly, the mentioned method was successfully performed to determine aliphatic amines in wastewater samples.

Performance and mechanism of siderite/zero-valent nickel composite material for removing Se(IV) from solution

79Se is a fission product in spent fuel with a half-life of up to 6.5 × 104 a, which is not controlled by solubility in aqueous solution and has strong mobility. These characteristics make it highly susceptible to migration in groundwater. Meanwhile, due to the negative charge of selenium ions, they are difficult to be fixed by buffer/backfill materials, engineering materials, geological materials and commonly used adsorption methods in near-field geochemical environments. Therefore, the fixation of 79Se has become a hot and difficult research topic both domestically and internationally. Therefore, this article aimed to simulate the removal of radioactive nuclide Se(IV) from high-level radioactive waste disposal repositories. On the basis of siderite (FeCO3), by adding zero-valent nickel (Ni0) and continuously optimizing sample preparation conditions, an economical, efficient and stable siderite/zero-valent nickel (FeCO3/Ni0) composite material was successfully prepared. Experimental studies on the removal of Se(IV) from solution were conducted under different conditions and the material was characterized using various modern methods from macro and micro perspectives, the performance and mechanism of FeCO3/Ni0 composite material for removing Se(IV) was explored deeply. The research results indicated that FeCO3/Ni0 had high potential as a candidate adsorbent for the removal of Se(IV) due to its easy synthesis, low-cost, high adsorption capacity and strong reduction.

삼원계를 통한 페북소스타트 고체분산체 개발 및 평가

Febuxostat is classified as a biopharmaceutical with low solubility in aqueous solution and high intestinal permeability (Biopharmaceutics Classification System [BCS] Class II drug). The solubility of a drug has the characteristic of increasing as pH increases. This study aims to improve the dissolution of febuxostat with Neusilin® US2 and Gelucire®50/13 by a solvent evaporation method. The optimal formulation (solid dispersion, SD1) is developed as a solid dispersion of febuxostat : Gelucire®50/13 : US2®= 1:2:4 (w/w), with a final weight of 280 mg. The dissolution of SD1 in distilled water is 72.0±2.8%, which is 1.67-fold higher than that of the commercial product, Feburic Tab® (43.2±1.8%). The SD1 formulation is believed to have improved dissolution due to changes in physicochemical properties (thermal, interaction, and crystallinity). In conclusion, through the solid dispersion manufacturing method, febuxostat is changed from a crystalline form to an amorphous form in SD1 formulation, and the improved dissolution of febuxostat formulation is developed.

Numerical investigation of carbon dioxide capture using nanofluids via machine learning

Using nanofluids to capture CO2 is a promising method of reducing emissions. The goal of this study was to develop models that could forecast how well water-based nanofluids would absorb CO2. Several machine learning models, such as Decision Tree, Random Forest, eXtreme Gradient Boosting, and K-Nearest Neighbors, underwent training using a total of 1306 experimental datasets. These datasets contained information on the CO2 solubility in aqueous solutions for different types of nanoparticles. In terms of Average Absolute Relative Deviation (AARD%), Mean Absolute Error (MAE), Relative Absolute Error, Mean Squared Error, and Correlation Coefficient, the predictive performance on separate test data was assessed. The XGBoost model demonstrates a higher degree of accuracy in simulating the absorption capacity of aqueous nanofluid compared to other models. This is evident through the AARD value of 2.8%, MSE of 0.00084, MAE of 0.012 and an R value of 0.992. The research provides insight into the utilization of different machine learning algorithms for simulating the absorption of CO2 by nanofluids. By employing accurate data-driven models, the efficiency of nanofluid-based CO2 capture processes can be enhanced through improvements in their design and operating conditions.

Microalbuminuria sensitive near‐infrared AIE probe for point‐of‐care evaluating kidney diseases

AbstractUrinary microalbumin (mALB) serves as an exceptionally sensitive indicator for the early detection of kidney damage, playing a pivotal role in identifying chronic renal failure and kidney lesions in individuals. Nevertheless, the current fluorescent methodologies for point‐of‐care (POC) diagnosis of mALB in real urine still exhibit suboptimal performance. Herein, the development and synthesis of QM‐N2, an albumin‐activated near‐infrared (NIR) aggregation‐induced emission (AIE) fluorescent probe, are presented. The strategic incorporation and positioning of quaternary ammonium salts within the quinoline‐malononitrile (QM) scaffold significantly influence solubility and luminescence characteristics. Specifically, the quaternary ammonium salt‐free variant, QM‐OH, and the quaternary ammonium salt integrated at the donor function group (DFG) site, QM‐N1, display limited solubility in aqueous solutions while demonstrating a distinct fluorescence signal. Conversely, the incorporation of quaternary ammonium salt at the conformational functional group (CFG) site in QM‐N2 imparts superior dispersibility in water and reduces the initial fluorescence. Furthermore, the integration of a well‐defined D‐π‐A structure within QM‐N2 enables itself with near‐infrared emission, which is crucial for mitigating interference from autofluorescence present in urine samples. Upon interaction with albumin, QM‐N2 forms a tight bond with the IIA site of the subdomain of human serum albumin (HSA), inducing alterations in protein configuration and constraining the intrinsic motion of fluorescent molecules. This interaction induces fluorescence, facilitating the sensitive detection of trace albumin. Ultimately, QM‐N2 is applied for POC testing of mALB using portable equipment, particularly in the diagnosis of mALB‐related diseases, notably chronic renal failure. This positioning underscores its potential as an ideal candidate for self‐health measurement at home or in community hospitals.

Re-engineering and regulating molecular architecture of synthetic capsaicin for enhanced water-based degradation performance

Synthetic capsaicin, also known as pelargonic acid vanillylamide (PAVA), constitutes the primary component in riot control agents. Due to the propensity of PAVA agglomerated in aqueous environments, the interaction between the active site of PAVA molecular and catalyst was restricted, consequently reducing its degradation efficiency in water-based oxidizing agents. This study used a cationic surfactant, dodecyl trimethyl ammonium chloride (DTAC), in combination with KOH for the precise regulation and arrangement of PAVA molecules, resulting in the formation of a distinctive hydrophilic structure. This approach resolved its poor solubility in aqueous solutions while the relationship between solubility and degradation rate was obtained. The frontier orbital distribution and surface electrostatic potential distribution of PAVA molecular were predicted through first-principles calculation. The mechanism of PAVA solubilization was studied by 1H NMR techniques and infrared spectroscopy methods. The results showed that KOH substitutes the phenolic hydroxyl group “–OH” of PAVA, forming potassium phenoxide “–OK”, which enhanced the solubility of PAVA in water. Additionally, KOH might reduced the surface tension in the solution. It promotes the formation of the DTAC/PAVA complex micelle structure, which exhibited the PAVA agglomerates to exposing the catalytic activation reaction sites and accelerating the catalytic oxidation.