Solubility Range Research Articles

Polymerizable deep eutectic solvent enables flexible gel formation for motion sensor and anti-UV film

Specific applications of gels can raise multiple demands, including low cost, elasticity, adaptability to wide temperature ranges, conductivity, and reduced hazards, thereby presenting diverse challenges for one material. Deep eutectic solvents (DESs) offer unexpected solutions to tackling the challenging task. Here, we mixed anhydrous diallyldimethylammonium chloride (DMDAAC) and urea to synthesize a polymerizable DES with a wide range of solubility. It can polymerize to form versatile DES gel upon photoinitiation. The gel exhibited high transparency (∼94 %), a wide range of temperature tolerance (−40 ∼ 100 °C), outstanding elastic properties (ε > 2400 %), good conductivity (0.05 mS·cm−1) and self-healing capability. The pristine gel film was successfully applied to motion sensors, while the DES gel with lignin was also employed as an elastic anti-UV film. Moreover, its water-solubility and non-hazardous compositions suggest the minimize environmental impact of the DES gel. This polymerizable DES can not only boost the development of electronic devices like motion sensors, but also inspire more creative ideas in promising applications of DESs and DES gels.

Inaccuracy principle and dissolution mechanism of lithium iron phosphate for selective lithium extraction from brines

The electrochemical lithiation/delithiation (ELD) method with the typical active materials being LiFePO4 and LiMn2O4, is the next generation technique for the selective lithium extraction from slat-lake brines owning to the advantages of high selectivity and excellent capacity and feasibility. However, the dissolution of LiFePO4/FePO4 (LFP/FP) during the ELD is seldom studied and an inaccurate measurement method for dissolution may result in obtaining an incorrect feasible application range for LFP/FP. Here, electrochemical workstation-electrochemical quartz crystal microbalance (EW-EQCM) is first utilized in the brine system to acquire the in-situ dissolution behavior of LFP/FP redox couple and verify the inaccuracy principle of the dissolution measurement. Both experimental results and thermodynamic calculations demonstrated that the accurate dissolution ratios can only be obtained by iron ions and phosphates at pH < 2.7 and pH < 5.3, respectively, which is induced by the narrow soluble range of iron ions and the formation of Ca5(PO4)3OH and Mg3(PO4)2 precipitation. In addition, the stable pH range of LFP and FP is 4 to 10 and 3 to 5, respectively, and the dissolution is caused by the formation of thermodynamically more stable metal ions, metal ion complexes, and metal ion hydroxides. At the optimum pH, the capacity can maintain 35 mg/g with average dissolution ratios of the cathode and anode lower than 0.1 %. This research sheds light on the accurate dissolution measurement range and method, dissolution mechanism and feasible application range of the LFP/FP redox couple.

Understanding Lithium-Gold Electrochemical Reactions Using Operando X-Ray Diffraction

Gold electrodes are used in lithium-based battery research as catalysts and micro / quasi-reference electrodes despite their high cost and unclear reactivity with lithium. Here we present an investigation of the electrochemical reactions of gold-lithium (Au-Li) mixtures using variable-temperature electrochemistry and operando X-ray diffraction.Multiple solid solutions (alpha, beta, delta) and intermetallic phases (AuLi3, Au4Li15) are expected based on the equilibrium phase diagram.1 Previous electrochemical investigations conclusively identified only AuLi3;2,3 alpha and beta may be bypassed during lithium insertion, and the structure of delta is unclear.4 We are unaware of any previous reports of the electrochemical formation of Au4Li15. Metastable crystallographic solutions have been proposed.5 X-ray diffraction patterns collected during the galvanostatic lithiation of gold leaf (at 60 °C and a rate of ca. C/50) are provided in Figure 1. Reference diffraction patterns and the associated Powder Diffraction File card number are indicated, along with proposed phases.4,5 X-ray and electrochemical data align with earlier results suggesting that the equilibrium alpha and beta phases are seemingly bypassed during the first insertion. Delta is the first phase to form at a potential of 0.25 V vs. Li/Li+, followed by the formation of AuLi3 at 0.15 V vs. Li/Li+ at all conditions and Au4Li15 at 0.05 V vs. Li/Li+ in select conditions. Electrochemical data suggests AuLi3 may also have a small range of solubility. Peaks associated with AuLi3 and Au4Li15 align with existing literature but peaks associated with delta do not. Reactions are reversible to delta, followed by the formation of another phase near 0.3 V vs. Li/Li+ and alpha at potentials above 0.4 V vs. Li/Li+ during lithium removal. Significant hysteresis is present in cell potential and reaction pathways in the low-lithium content region. The second cycle (not shown) is reversible between alpha (not pure gold) and the terminal phase without a significant loss in capacity. Alternative crystallographic unit cell(s) for delta and other gold-lithium phases will be described.While the delta / AuLi3 reaction exhibited a consistent potential during lithium insertion and removal, the potential otherwise varied strongly with temperature, rate, and composition, implying that gold quasi-reference electrodes may not be suitable for lithium-ion battery research.

Experimental investigation and thermodynamic analysis of TiC–Fe cermets with Mo additions

Abstract In this study, the effects of Mo additions on the microstructure, hardness and bending strength of TiC–Fe cermets manufactured by spark plasma sintering were investigated by scanning electron microscopy, X-ray diffraction and mechanical properties tests. Thermodynamic calculations were utilized to analyze the evolution of the microstructure. The results show that the conventional core/rim structure was not formed during the solid-phase sintering of TiC–Fe cermets. The heat-treatment process and reasonable Mo addition can effectively enhance the overall performance of the alloys. With the addition of minor Mo, the hardness of the sintered cermets improved significantly, which was attributed to the solid solution strengthening mechanism of Mo in Fe binder. However, excessive Mo exceeded the solubility range of Fe binder and precipitated in the form of M 6C and Mo2C phases, which damaged the bending strength of the heat-treated cermets.

Experimental Investigation of Phase Equilibria in the Ti-Cr-V System at 1000–1200 °C

Ti-Cr-V-based alloys have been utilized across various domains, including aerospace structural and functional materials and hydrogen storage materials. Investigating the phase relations in the Ti-Cr-V system is significant in supporting the material design for these applications. In the present work, the isothermal sections at 1000, 1100, and 1200 °C for the Ti-Cr-V system were precisely determined through a systematic investigation using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The phase region of Cr2Ti was entirely elucidated for the first time. As the temperature decreased from 1200 to 1000 °C, the V solubility range of Cr2Ti increased from 5.3 wt.% to 10.0 wt.%, while the Ti solubility range essentially remained constant at approximately 31.0–33.9 wt.%. In addition, it was suggested that the stable structure of Cr2Ti was C36 at 1200 °C and C15 at 1000 and 1100 °C. The present work will support thermodynamic re-assessment research.

Selection of ionic liquid electrolytes for high-performing lithium-sulfur batteries: An experiment-guided high-throughput machine learning analysis

The polysulfide (PS) shuttle mechanism (PSM) is one of the most significant challenges of lithium-sulfur (Li-S) batteries in achieving high capacity and cyclability. One way to minimize the shuttle effect is to limit the PS solubilities in the battery electrolyte. Ionic liquids (IL) are particularly suited as electrolyte solvents because of their tunable physical and chemical properties. In this work, thousands of ILs are screened to narrow down potentially viable candidates to be used as electrolytes in Li-S batteries. To that end, the COnductor-like Screening Model for Realistic Solvents (COSMO-RS) calculations are performed over more than 36,000 ILs. An extensive database containing PS solubilities and other relevant properties is constructed at 25 °C. First, the effectiveness of the COSMO-RS calculations is experimentally tested with six different ILs having a wide range of solubility and viscosity values; a strong correlation between the PS solubility and battery performance is obtained. After specifying the target limits for promising ILs using the experimental battery performance data, machine learning (ML) tools are used to predict and identify the relationship between IL properties and PS solubilities and structural and molecular descriptors of ILs. The extreme gradient boosting (XGBoost) method successfully predicts the solubility and property values. Association rule mining (ARM) and the feature importance analysis show that anion descriptors are more dominant, whereas cations have less impact on the solubilities and properties of ILs. Finally, the imidazolium and pyridinium ILs with bis_imide and borate anion groups are identified as the most promising ones.

Metal Substitutions (M = Al, Ga, In; Sn, Ge; and Mn, Fe, Co) in ZnS: Sphalerite versus Wurtzite Formation.

A series of Zn1-xMxS polycrystalline samples were synthesized via a solid-state reaction in closed vessels to examine the solubility of foreign M cations within the wurtzite ZnS structure, employing quenching or slow cooling processes to favor specific polymorphs. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses revealed diverse structural behaviors across different cations. Group 13 elements (Al and Ga) formed solid solutions with a wurtzite structure, while In showed complex layer stacking defects. For 3d magnetic cations (Mn, Fe, and Co), a broad solubility range in the hexagonal structure was noted for Mn, whereas Fe and Co more readily formed cubic structures, with solubilities similar to Mn in the sphalerite form. Despite structural differences, magnetic susceptibilities and spin freezing temperatures for Fe and Co were comparable. Group 14 elements showed varied behaviors: Sn was insoluble in ZnS, as attested by unchanged unit cell parameters and surface crystallite Sn, whereas Ge only formed in the cubic phase with a solubility limit of x ≈ 0.2. The study discusses these variations in solubility and structure in terms of oxidation states, ionic-covalent radius, and coordination preferences in sulfides.

Thermodynamic assessment of the Cr–Si binary system

A thermodynamic evaluation of the Cr–Si system was performed concerning the latest experimental phase diagram and with the aid of first-principles calculations. The thermodynamic parameters for the Gibbs energy of pure Cr were modified based on the new experimental value of 1861 °C for the melting point of pure Cr, which was previously reported as 1907 °C in the SGTE database. The Gibbs energy descriptions of the Cr3Si and Cr5Si3 phases were revised using Cr3(Cr,Si)- and (Cr,Si)5Si3-type two-sublattice models to reproduce the latest experimental results of their solubility composition ranges, that is, Cr3Si extending toward the Cr-rich side and Cr5Si3 extending toward the Si-rich side from the stoichiometry. The CrSi and CrSi2 phases were considered line compounds with no solubility range, and the solubility of Cr in the Si phase was ignored. A set of self-consistent thermodynamic parameters for the Cr–Si system was obtained using the CALPHAD technique. The phase diagrams calculated using the optimized parameters showed reasonable agreement with the latest phase equilibrium data and thermodynamic property data in the literature, including the enthalpy of mixing, formation enthalpy, and chemical potential diagrams of Cr and Si in the equilibrium phases.

Phase equilibria in the NiO-ZnO-SiO2 and PbO-NiO-ZnO-SiO2 systems

Experimental investigation and thermodynamic modeling of the phase equilibria in the (PbO)-NiO-ZnO-SiO2 system has been undertaken to characterize Ni behavior in high-Zn slags. Phase equilibria data at 790–1700 °C were obtained through equilibration of synthetic mixtures in sealed silica ampoules or Pt-Ir / Au foils, rapid quenching, and electron probe X-ray microanalysis. Phase equilibria and liquidus isotherms of the NiO-ZnO-SiO2 system in the tridymite/cristobalite SiO2, monoxide (Ni,Zn)O, zincite (Zn,Ni)O, olivine (Ni,Zn)2SiO4 and willemite (Zn,Ni)2SiO4 phase fields were measured and the extent of the 2-liquid immiscibility gap over cristobalite was determined. Additional solid solutions: larsenite Pb(Zn,Ni)SiO4 and melilite Pb2(Zn,Ni)Si2O7 were measured in the PbO-NiO-ZnO-SiO2 system. It was found that NiO partially substitute ZnO in larsenite and melilite and may form a complete range of solubility in barysilite Pb8(Zn,Ni)Si6O21. New data were used for developing a thermodynamic database to describe the Pb/Cu-containing complex system for characterizing Ni behavior in Zn-containing slags.

Characterization and Assessment of Physical Properties of 3 Single Syringe Hydraulic Cement–based Sealers

IntroductionA number of sealers with different chemistries are badged as Bioceramic, implying biological activity, but have dissimilar properties, which has implications on the sealer properties and will affect the quality and outcome of root canal treatment. This study aimed to assess the physical and chemical properties of 3 hydraulic cement–based sealers, namely BC Universal sealer compared with Totalfill BC sealer and AH Plus Bioceramic. MethodsThe microstructure and composition of the sealers were assessed using scanning electron microscopy and energy dispersive spectroscopy after setting. The crystalline phases were assessed by X-ray diffraction analysis and the leachates were tested using inductively coupled plasma. All testing was performed at 0, 7, and 28 days. The physical properties of film thickness, flow, radiopacity, and solubility were evaluated using ISO 6876:2012 standards. ResultsAll 3 sealers contained calcium, zirconium, and silicon. Totalfill BC had the highest calcium release at 7 and 28 days followed by AH Plus Bioceramic and BC Universal sealer. All 3 sealers adhered to the ISO standard in terms of flow and radiopacity. BC Universal sealer was slightly over the range (>50 μm) for film thickness. All sealers exceeded the solubility range set by ISO 6876:2012. ConclusionAlthough these hydraulic cement sealers had similar components and delivery, the properties varied significantly. The testing of material properties to confirm the suitability for clinical use is necessary.

Synthesis of chitosan-based flocculant by dielectric barrier discharge modification and its flocculation performance in wastewater treatment.

As a typical type of organic flocculant, chitosan is limited by its poor water solubility and narrow pH range application. Grafting modification can improve chitosan's solubility and availability through linking macromolecular chains with other types of water-soluble groups or functional side groups. In this study, dielectric barrier discharge (DBD) was used to active the surface of chitosan, then activated chitosan was polymerized with acrylamide to synthesize a chitosan-based flocculant, chitosan-acrylamide (CS-AM). During the synthesis of CS-AM, the optimal conditions were determined as follows: discharge time of 5 min, discharge power of 60 W, total monomer mass concentration of 80 g L-1, polymerization time of 3 h, polymerization temperature of 70 °C, and m(CS) : m(AM) ratio of 1 : 3. The structure and morphological characteristics of CS-AM were investigated and analyzed by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric (TG) analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD) and N2 physical adsorption, respectively. The removal efficiency of kaolin suspension and CNTs suspension can reach up to 95.9% and 90.2% after flocculation of CS-AM. Furthermore, the zeta potential of the supernatant from the CS-AM treated kaolin suspension at different pH values was examined, and the flocculation mechanism of CS-AM was analyzed. This study provides new ideas for the preparation and development of modified chitosan and broadens its application in water treatment.

Supporting food effect prediction using biorelevant small scale in vitro solubility approaches

Thisstudy applies biorelevant fasted and fed simulated intestinal media (SIM) to comparethe solubility of griseofulvin, ibuprofen, and dipyridamole to investigate theprediction of food effects. These media cover over 90% of the human intestinalfluid variation in each state providing a comprehensive solubility range invitro. The results highlight that ibuprofen is unaffected by food but dipyridamoleand griseofulvin show an increased solubility in the fed state, suggesting positivefood effects in line with in vivo literature data. Drugs with solubility limitedabsorbable dose (SLAD) lower or close to the oral dose are more likely to presenta food effect, thus SLAD analysis could aid the prediction of food effects. Thisapproach may be applied in early drug development as a preliminary predictiontool.

Novel Approaches for Improving Solubility of Pyridinium Anolytes in Non-Aqueous Redox Flow Batteries

Organic redox flow batteries (ORFBs) offer significant promise as a means of efficient grid-scale energy storage to compliment the intermittent power supply of renewable energy sources such as solar and wind power. ORFBs efficiently store energy in the form of redox-active organic molecules (ROMs) by passing them over two polarized electrodes to generate an oxidized (catholyte) and a reduced (anolyte) species, which are held in separate tanks until energy is needed. Structural diversity of anolytes and catholytes for ORFBs has expanded dramatically over the past decade as researchers have raced to discover or design ROMs suitable for use in grid-scale energy storage devices; however, a lack of correlations between ROM structure and a desired chemical or physical property has led to a “guess and check” approach that can overlook possibly transformative electrolyte structures. Recent work has demonstrated the ability to employ multivariate regression analysis to correlate computationally derived structural descriptors of ROMs to their corresponding stability. Based on this, we considered the possibility of employing a similar approach to identify quantitative structure-property relationships (QSPRs) for critical physical properties of ORFB electrolytes, such as solubility.Electrolyte solubility is an essential design characteristic in ORFBs as it directly impacts the corresponding battery’s energy storage capacity. Nevertheless, the fundamental question, “What makes an electrolyte soluble?” (especially in organic solvents) still lacks a concise answer despite decades of progress. As part of a collaboration with the Guarr group at the Michigan State University Bioeconomy Institute, our group has identified a novel class of pyridinium anolytes with exceptionally low redox potentials and highly persistent charged states. We will discuss our group’s recent progress to combine experimental and computational techniques to develop QSPR models to accurately predict solubility of pyridinium anolytes. The resulting models have provided new insights into the role that self-interaction between anolyte species in solution plays in dictating their corresponding solubility. Using these models, we have successfully expanded the solubility range for a class of pyridinium derivatives by >200% in acetonitrile.

Preparation of the modified chitosan flocculant introduced acryloyloxyethyl trimethyl ammonium chloride and 2-acrylamido-2-methyl propane sulfonic acid for the treatment of papermaking wastewater

To solve the shortcomings of poor solubility, low cationic strength, and small molecular weight of chitosan (CTS), acryloyloxyethyl trimethyl ammonium chloride (DAC) and 2-acrylamido-2-methylpropanesulfonic acid (AMPS) were introduced into the amino group of chitosan by graft copolymerization, and the modified chitosan flocculant CTS-DAC-AMPS was successfully prepared. The performance of CTS-DAC-AMPS in the treatment of papermaking wastewater was investigated, and the mechanism of the flocculation process was analyzed. The results showed that the crystal habit of CTS-DAC-AMPS was reduced, and the solubility range was broadened compared with CTS due to the introduction of DAC and AMPS. In addition, CTS-DAC-AMPS with quaternary ammonium and sulfonic groups prompted its cationic strength stronger than CTS. In addition to high thermal stability, CTS-DAC-AMPS, composed of two CTS molecules, one DAC molecule, and one AMPS molecule, had a long molecular chain. The results of flocculation experiments showed that the performance of CTS-DAC-AMPS in treating papermaking wastewater was better than that of unmodified CTS and commercially available flocculants. Based on the experimental results, the mechanism of CTS-DAC-AMPS treatment of papermaking wastewater was mainly charge neutralization.

Structured solubility behaviour in fed simulated intestinal fluids

Intestinal drug solubility is a key parameter controlling absorption after the administration of a solid oral dosage form. The ability to measure fed state solubility in vitro is limited and multiple simulated intestinal fluid recipes have been developed but with no consensus which is optimal. This study has utilised nine bioequivalent simulated fed intestinal media recipes that cover over 90% of the compositional variability of sampled fed human intestinal fluid. The solubility of 24 drugs (Acidic; furosemide, ibuprofen, indomethacin, mefenamic acid, naproxen, phenytoin, piroxicam, valsartan, zafirlukast: Basic; aprepitant, atazanavir, bromocriptine, carvedilol, dipyridamole, posaconazole, tadalafil: Neutral; acyclovir, carbamazepine, felodipine, fenofibrate, griseofulvin, itraconazole, paracetamol, probucol) has been assessed to determine if structured solubility behaviour is present. The measured solubility behaviour can be split into four categories and is consistent with drug physicochemical properties and previous solubility studies. For acidic drugs (category 1) solubility is controlled by media pH and the lowest and highest pH media identify the lowest and highest solubility in 90% of cases. For weakly acidic, basic and neutral drugs (category 2) solubility is controlled by media pH and total amphiphile concentration (TAC), a consistent solubility pattern is evident with variation related to individual drug media component interactions. The lowest and highest pH × TAC media identify the lowest and highest solubility in 70% and 90% of cases respectively. Four drugs, which are non-ionised in the media systems (category 3), have been identified with a very narrow solubility range, indicating minimal impact of the simulated media on solubility. Three drugs exhibit solubility behaviour that is not consistent with the remainder (category 4). The results indicate that the use of two bioequivalent fed intestinal media from the original nine will identify in vitro the maximum and minimum solubility values for the majority of drugs and due to the media derivation this is probably applicable in vivo. When combined with a previous fasted study, this introduces interesting possibilities to measure a solubility range in vitro that can provide Quality by Design based decisions to rationalise drug and formulation development. Overall this indicates that the multi-dimensional media system is worthy of further investigation as in vitro tool to assess fed intestinal solubility.

Protein Nanocarriers Capable of Encapsulating Both Hydrophobic and Hydrophilic Drugs.

Protein nanoparticles are promising targeted drug delivery carriers due to their low toxicity, biodegradability, and abundance of proteins in natural sources. Also, protein nanoparticles enable surface modification with other functional proteins or carbohydrate ligands, which improves the efficacy of targeted drug delivery. Nonetheless, a persistent challenge remains to make versatile protein nanoparticles that deliver diverse types of drugs in a wide range of water solubility. Herein, we describe the methods to fabricate nanoparticles made from bovine serum albumin (BSA) that allow for the encapsulation of both hydrophilic and hydrophobic drug molecules, doxorubicin and bilirubin, respectively.

Adapting physiologically-based pharmacokinetic models for machine learning applications

Both machine learning and physiologically-based pharmacokinetic models are becoming essential components of the drug development process. Integrating the predictive capabilities of physiologically-based pharmacokinetic (PBPK) models within machine learning (ML) pipelines could offer significant benefits in improving the accuracy and scope of drug screening and evaluation procedures. Here, we describe the development and testing of a self-contained machine learning module capable of faithfully recapitulating summary pharmacokinetic (PK) parameters produced by a full PBPK model, given a set of input drug-specific and regimen-specific information. Because of its widespread use in characterizing the disposition of orally administered drugs, the PBPK model chosen to demonstrate the methodology was an open-source implementation of a state-of-the-art compartmental and transit model called OpenCAT. The model was tested for drug formulations spanning a large range of solubility and absorption characteristics, and was evaluated for concordance against predictions of OpenCAT and relevant experimental data. In general, the values predicted by the ML models were within 20% of those of the PBPK model across the range of drug and formulation properties. However, summary PK parameter predictions from both the ML model and full PBPK model were occasionally poor with respect to those derived from experiments, suggesting deficiencies in the underlying PBPK model.

Investigation of the Structural, Dielectric, Magnetic, and Magnetoelectric Properties of Nd-Substituted Sr3Co2Fe24O41 Z-Hexaferrite

The Neodymium (Nd) substituted Sr-based Z-Hexaferrites having composition Sr3-xNdxCo2Fe24O41 (x = 0, 0.15, 0.30 and 0.45) corresponding to pristine, 5, 10 and 15% substitution were prepared using solid-state reaction method in pre-optimized rare Earth metal solubility range (x ≤ 0.45) and labeled as SCFO, SNCFO5, SNCFO10 and SNCFO15, respectively. X-ray diffractometer and Scanning Electron Microscopy (SEM) were utilized to investigate the prepared samples’ structure and grain morphology. The X-ray diffraction (XRD) patterns confirmed Z-hexaferrite formation with adequate phase purity. Dielectric measurements exhibited a relaxation-type, frequency-dependent, and thermally activated dielectric response across all prepared samples. In Nd substituted SCFO, the obtained value of coercivity (Hc) ranges from 52.2–68.45 oersted, confirming a soft magnetic behavior. Magnetoelectric coupling coefficient(α) recorded at room temperature has a maximum value of 0.2133 mV cm−1Oe−1 for the pristine sample and this value of α varies with Nd substitution for all prepared samples.

Effect of Fibres on Physico-Mechanical Properties of Bulk-Fill Resin Composites.

To measure the flexural strength (FS) of bulk-fill resin composites and assess their long-term water absorption and solubility properties with and without the inclusion of short glass fibres. One resin composite, everX Flow with fibres, and four commercially available bulk-fill composites without fibres, namely, PALFIQUE, Activa, SDR Plus, and Filtek Bulk Fill One, were tested. Six specimens (2 × 2 × 25 mm) were fabricated for each material and stored in water for 1 day and 30 days to measure the flexural strength using a three-point bending test. To evaluate water absorption and solubility, circular disks measuring 15 × 2 mm (n = 5) were immersed in water for 60 days, and their weights were recorded periodically. After 60 days, the specimens were dried for an additional 21 days to determine solubility. Flexural strength values ranged from 101.7 to 149.1 MPa. Significant distinctions were observed among the resin composites at the onset of the study (p < 0.05). The highest FS value was identified in everX Flow, while ACT exhibited the lowest (p < 0.05). However, the flexural strength values exhibited a significant decrease with increased storage time (p < 0.05), except for ACT, which demonstrated a noteworthy increase. Concerning water absorption and solubility, ACT displayed the highest absorption, while the range of solubility varied from -0.88 to 5.8 μg/mm3. ACT also had the highest solubility, whereas everX Flow exhibited negative solubility. The addition of short fibres, along with potential differences in matrix composition, enhanced the flexural strength of everX Flow. However, the substantial reduction in flexural strength observed in everX Flow and SDR following exposure to water corroborates the manufacturers' recommendation to apply a conventional resin composite cap on these materials.

A machine learning approach for thermodynamic modeling of the statically measured solubility of nilotinib hydrochloride monohydrate (anti-cancer drug) in supercritical CO2

Nilotinib hydrochloride monohydrate (NHM) is an anti-cancer drug whose solubility was statically determined in supercritical carbon dioxide (SC-CO2) for the first time at various temperatures (308–338 K) and pressures (120–270 bar). The mole fraction of the drug dissolved in SC-CO2 ranged from 0.1 × 10–5 to 0.59 × 10–5, corresponding to the solubility range of 0.016–0.094 g/L. Four sets of models were employed to evaluate the correlation of experimental data; (1) ten empirical and semi-empirical models with three to six adjustable parameters, such as Chrastil, Bartle, Sparks, Sodeifian, Mendez-Santiago and Teja (MST), Bian, Jouyban, Garlapati-Madras, Gordillo, and Jafari-Nejad; (2) Peng-Robinson equation of state (Van der Waals mixing rule, had an AARD% of 10.73); (3) expanded liquid theory (modified Wilson model, on average, the AARD of this model was 11.28%); and (4) machine learning (ML) algorithms (random forest, decision trees, multilayer perceptron, and deep neural network with respective R2 values of 0.9933, 0.9799, 0.9724 and 0.9701). All the models showed an acceptable agreement with the experimental data, among them, the Bian model exhibited excellent performance with an AARD% of 8.11. Finally, the vaporization (73.49 kJ/mol) and solvation (− 21.14 kJ/mol) enthalpies were also calculated for the first time.