Solution State Research Articles

Gaussian–Student’s t Mixture Distribution-Based Robust Kalman Filter for Global Navigation Satellite System/Inertial Navigation System/Odometer Data Fusion

Multi-source heterogeneous information fusion based on the Global Navigation Satellite System (GNSS)/Inertial Navigation System (INS)/odometer is an important technical means to solve the problem of navigation and positioning in complex environments. The measurement noise of the GNSS/INS/odometer integrated navigation system is complex and non-stationary; it approximates a Gaussian distribution in an open-sky environment, and it has heavy-tailed properties in the GNSS challenging environment. This work models the measurement noise and one-step prediction as the Gaussian and Student’s t mixture distribution to adjust to different scenarios. The mixture distribution is formulated as the hierarchical Gaussian form by introducing Bernoulli random variables, and the corresponding hierarchical Gaussian state-space model is constructed. Then, the mixing probability of Gaussian and Student’s t distributions could adjust adaptively according to the real-time kinematic solution state. Based on the novel distribution, a robust variational Bayesian Kalman filter is proposed. Finally, two vehicle test cases conducted in GNSS-friendly and challenging environments demonstrate that the proposed robust Kalman filter with the Gaussian–Student’s t mixture distribution can better model heavy-tailed non-Gaussian noise. In challenging environments, the proposed algorithm has position root mean square (RMS) errors of 0.80 m, 0.62 m, and 0.65 m in the north, east, and down directions, respectively. With the assistance of inertial sensors, the positioning gap caused by GNSS outages has been compensated. During seven periods of 60 s simulated GNSS data outages, the RMS position errors in the north, east, and down directions were 0.75 m, 0.30 m, and 0.20 m, respectively.

Electron Push‐Pull Effects for Solution and Solid‐State Emission Control in Naphthalene 2,7‐Position‐Based Donor–Acceptor–Donor

Organic luminescent materials have garnered significant attention owing to their potential applications, particularly due to their inherent flexibility and ease of processability. Accordingly, the development of strategies that enable precise control over both intra‐ and intermolecular interactions, which directly influence their emission properties, is of paramount importance. In this study, a series of naphthalene (NAP) 2,7‐position‐based donor–acceptor–donor (D–A–D) compounds were designed and synthesized to investigate the electron push‐pull effect on intramolecular and intermolecular interactions. The energy bandgaps of the compounds were controlled by the electron push‐pull effect, resulting in red‐shifted emission within 48 nm in the order of increasing electron‐donating ability in solution state. Experimental data and theoretical calculations show that the intramolecular charge transfer (ICT) properties of D–A–D compounds are systematically controlled by electron push‐pull effects. In particular, the solid‐state emission of the compounds showed a redshift in the same order as that observed in solution. This solid‐state emission behavior is explained by the electron push‐pull effect‐dependent intermolecular interactions. Consequently, an efficient single‐molecule and multi‐molecule emission control strategy by electron push‐pull effect in NAP 2,7‐position‐based D–A–D was successfully demonstrated.

Influence of aqueous constituents on hexafluoropropylene oxide trimer acid (HFPO-TA) defluorination by UV/sulfite/iodide system

ABSTRACT HFPO-TA is an emerging alternative to traditional perfluoroalkyl substances (PFASs), which is characterized by its biotoxicity and persistence. The UV/sulfite/iodide photo-induced hydrated electrons system can effectively degrade HFPO-TA under mild conditions. However, the effects of water quality on this system need to be urgently investigated. This study explored the impact of common aqueous constituents (Cl−, HCO3−, PO43−, and HA) on the defluorination efficiency of HFPO-TA by the UV/sulfite/iodide system. Results indicated that low concentrations of Cl− (<1.0 mM), PO43− (<0.01 mM), and HA (<5.0 mg/L) have negligible impact on defluorination efficiency. However, as concentrations increase, these constituents can interact with photosensitizers or reactive species within the system, leading to a decrease in defluorination efficiency. HCO3−, in their various solution states, can compete with HFPO-TA for the hydrated electron (eaq−) or engage directly with the photosensitizer, resulting in a hindrance to the defluorination capabilities of the system. Furthermore, it was identified that the defluorination efficacy of the UV/sulfite/iodide for HFPO-TA in Xiaoqing River was diminished relative to that in deionized water, primarily due to the presence of Cl− and HCO3−. Adsorption/desorption or nanofiltration pretreatment using highly selective materials such as COFs can effectively mitigate this problem.

Hydrogen bonding state of THF-H2O solution analyzed by 2D Raman-COS spectroscopy

Hydrogen bonding state of THF-H2O solution analyzed by 2D Raman-COS spectroscopy

Equally high efficiencies of organic solar cells processed from different solvents reveal key factors for morphology control

AbstractThe power conversion efficiency of organic solar cells (OSCs) is exceeding 20%, an advance in which morphology optimization has played a significant role. It is generally accepted that the processing solvent (or solvent mixture) can help optimize morphology, impacting the OSC efficiency. Here we develop OSCs that show strong tolerance to a range of processing solvents, with all devices delivering high power conversion efficiencies around 19%. By investigating the solution states, the film formation dynamics and the characteristics of the processed films both experimentally and computationally, we identify the key factors that control morphology, that is, the interactions between the side chains of the acceptor materials and the solvent as well as the interactions between the donor and acceptor materials. Our work provides new understanding on the long-standing question of morphology control and effective guides to design OSC materials towards practical applications, where green solvents are required for large-scale processing.

Boosting the circularly polarized luminescence of pyrene-tiaraed pillararenes through mechanically locking

Attributed to their unique dynamic planar chirality, pillar[n]arenes, particularly pillar[5]arenes, have evolved as promising platforms for diverse applications such as circularly polarized luminescence (CPL) emitters. However, due to the unit flipping and swing, the achievement of excellent CPL performances of pillar[5]arenes in solution state remains a formidable challenge. To deal with this key issue, a mechanically locking approach has been successfully developed, leading to boosted dissymmetry factor (glum) values of pyrene-tiaraed pillar[5]arenes up to 0.015 through the formation of corresponding [2]rotaxanes. More importantly, taking advantage of the stably locked co-conformers, these resultant [2]rotaxanes maintain excellent CPL performances in diverse solvents and wide range of concentrations, making them promising candidates for practical applications. According to this proof-of-concept study, we have not only successfully developed a powerful strategy for the rational design of chiral luminescent materials with desired CPL performances but also contributed a promising platform for the construction of smart chiral materials.

Unveiling the dual-state emissive behaviour of 4,6-diarylpyrimidin-2-amines through a plug-and-play approach

We present here a series of 4,6-diarylpyrimidin-2-amine derivatives (5a-j) with tunable optical properties both in the solid and solution states. Our plug-and-play fluorophore design demonstrates that the aryl groups at the 4th and 6th positions of the 2-aminopyrimidine core enable distinct optical characteristics for each derivative. The fluorophore design concept was validated using theoretical and spectroscopic methods. The designed compounds were synthesised in moderate to good yields, and their structures were confirmed via IR, NMR, HRMS, and single-crystal XRD analyses. Optical studies revealed that varying the aryl substituents significantly impacts absorption, emission, and bandgap values in both phases. The absolute quantum yields (ϕF) of the synthesised derivatives ranged from 8.11 to 71.00% in DMF and 5.86–29.43% in thin films, with fluorescence lifetimes (τ) between 0.8 and 1.5 ns in DMF and 0.63–3.16 ns in films, respectively. CIE (Commission Internationale de l’Éclairage) diagrams indicate blue-green emission for 5a-j in the visible spectrum. The electrochemical analysis confirmed that the HOMO/LUMO (Highest Occupied Molecular Orbital/Lowest Unoccupied Molecular Orbital) energy levels can be modulated by altering the substituent rings. These results highlight the dual-state emission properties of 2-aminopyrimidine fluorophores, demonstrating their potential for a wide range of optoelectronic and advanced applications.

AI-powered financial crime prevention with cybersecurity, IT, and data science in modern banking

Financial crime in modern banking has evolved significantly with the digital transformation of financial services, presenting unprecedented challenges to traditional prevention methods. This comprehensive review examines the integration of artificial intelligence (AI), cybersecurity frameworks, and data science methodologies in combating financial crime within the banking sector. We analyze the current state of AI-powered solutions, including machine learning models, real-time detection systems, and advanced analytics frameworks that have transformed financial crime prevention. The review synthesizes findings from recent studies and industry implementations, highlighting the synergistic relationship between AI technologies and cybersecurity measures in creating robust defense mechanisms. Our analysis reveals that while AI-powered solutions demonstrate superior detection rates and reduced false positives compared to traditional methods, significant challenges remain in areas of data privacy, regulatory compliance, and system integration. The paper concludes by identifying critical research gaps and proposing future directions for enhancing the effectiveness of AI-based financial crime prevention systems. This review provides valuable insights for researchers, banking professionals, and policymakers working at the intersection of AI, cybersecurity, and financial crime prevention.

Organic Moiety on Sn(IV) Does Matter for In Vitro Mode of Action: nBu3Sn(IV) Compounds with Carboxylato N-Functionalized 2-Quinolones Induce Anoikis-like Cell Death in A375 Cells

Objectives: New tributyltin(IV) complexes containing the carboxylate ligands 3-(4-methyl-2-oxoquinolin-1(2H)-yl)propanoic acid (HL1) and 2-(4-methyl-2-oxoquinolin-1(2H)-yl)acetic acid (HL2) have been synthesized. Methods: Their structures have been determined by elemental microanalysis, FT-IR and multinuclear NMR (1H, 13C and 119Sn) spectroscopy and X-ray diffraction study. A solution state NMR analysis reveals a four-coordinated tributyltin(IV) complex in non-polar solvents, while an X-Ray crystallographic analysis confirms a five-coordinated trigonal-bipyramidal geometry around the tin atom due to the formation of 1D chains. A theoretical structural analysis was performed by optimization employing B3LYP-D3BJ functional and 6-311++G(d,p)/def2-TZVP(Sn) basis sets for H, C, N, O/Sn, respectively. The interactions between tin(IV) and surrounding atoms were examined by QTAIM approach. The in vitro antiproliferative activity of the synthesized compounds was evaluated by MTT and CV assays versus MCF-7 (human breast adenocarcinoma), HCT116 (human colorectal carcinoma), A375 (human melanoma), 4T1 (mouse breast carcinoma), CT26 (mouse colon carcinoma) and B16 (mouse melanoma) tumor cell lines. Results: Both synthesized compounds (nBu3SnL1 and nBu3SnL2) exerted powerful micromolar IC50 cytotoxicity values and demonstrated high selectivity toward malignant cells. Both experimental drugs affected cell adhesion and induced anchorage independent apoptosis, a favorable type of cell death with an essential role in cancer dissemination prevention. The BSA-binding affinity of the obtained organotin compounds was followed by spectrofluorometric titration and molecular docking simulations. Conclusions: The tributyltin(IV) compounds selectively induce anoikis-like cell death in A375 cells, also highlighting the importance of the organic moiety on the tin(IV) ion in the mechanism of action.

Introducing of an Unexplored Aza-BODIPY Diradicaloids with 4-(2,6-Ditert-butyl)phenoxyl Radicals Located in 1,7-Positions of the Aza-BODIPY Core.

We have prepared and characterized two diradicaloid systems 5a and 5b that originated from the oxidation of a 1,7-(4-(2,6-di-tert-butyl)phenol)-substituted aza-BODIPY core. The aza-BODIPY diradicaloids were characterized by a large array of experimental and computational methods. The diamagnetic closed-shell state was postulated as the ground state in solution and a solid-state with the substantial thermal population originating from both open-shell diradical and open-shell triplet states observed at room temperature. Transient absorption spectroscopy indicates fast (<10 ps) excited state deactivation pathways associated with the target compounds' diradical character in solution at room temperature. Variable-temperature 1H NMR spectra indicate the solvent dependency of the diradical character in 5a and 5b. The diradicaloids could be stepwise reduced to the mixed-valence radical-anion and dianion states upon consequent single-electron reductions. Similarly, deprotonated 1,7-(4-(2,6-di-tert-butyl)phenol)-substituted aza-BODIPYs can be oxidized to the diradicaloid form. Both mixed-valence and dianionic forms exhibit an intense absorption in the NIR region. Density functional theory (DFT) and time-dependent DFT calculations were used to explain the transformations in the UV-Vis-NIR spectra of all target compounds.

On the Global Existence of Solution of the Comparison System and Vector Lyapunov Asymptotic Eventual Stability for Nonlinear Impulsive Differential Systems

In this paper, the existence of maximal solution of the comparison system as well as the asymptotic eventual stability of nonlinear impulsive differential equations with fixed moments of impulse is examined using the vector Lyapunov functions which is generalized by a class of piecewise continuous Lyapunov functions. It was distinctly established that the maximal solution of the comparison system majorizes the vector form of the Lyapunov functions. The novelty in the use of the vector Lypunov functions lies in the fact that the "restrictions" encountered by the scalar Lyapunov function is safely handled especially for large scale dynamical systems, since it involves splitting the Lyapunov functions into components so that each of the components can easily describe the behavior of the solution state. Together with comparison results, sufficient conditions for eventual stability and asymptotic are presented.

Swapping conventional doping with novel white light emission from La2O3: clitoria ternatea extract

The common flower Clitoria ternatea is gifted with organic dyes anthocyanin delphinidin and betalains betacyanin that exhibit broad emission peaks centered at 490 nm and 630 nm. These fresh emission bands in the blue-green and red regions make it a potential white light source that can swap the conventional rare-earth doped phosphor materials. By this line, the extract shows decent emission in its solution state. However, the emission intensity reduces rapidly after a while, owing to the high decay rate of organic dyes in their pure form. Thus, the floral extract is combined with the antioxidant La2O3, reducing the luminescence decay to a noticeable value. The complex formation does not alter the innate La2O3 crystal structure, identified by the XRD peaks, but aids with near-white emission. Upon complex formation, the optical band gap of the host La2O3 falls to the semiconductor range, from 5.1 eV to 2.5 eV. White light emission from La2O3: Clitoria ternatea complex is studied for different extract concentrations and heating conditions, and deemed as a potential replacement for conventional rare-earth doping.

In-situ X-ray analysis of cold alkali dissolution of cellulose pulps of various origin

AbstractThis article elucidates the dissolution of cellulose from different raw materials in NaOH aqueous solution via the combination of synchrotron-radiation-based SAXS/WAXS characterization. The X-ray measurements probed the mesostructure of the cellulose samples during the freeze-thawing cycle allowing tracking the initial swelling of the structure, the kinetics of disintegration of the cellulose crystallites as well as controlling the final state of the cellulose solution, i.e. presence or absence of cellulose aggregates. The individual SAXS and WAXS measurements were fitted and modelled to enable visualisation and tracking of the changes in the structure in relation to temperature during cooling and warming phases. To further increase the understanding of the parameters affecting dissolution different cellulose samples and solution compositions were considered. For this purpose the effect of increasing the concentration of NaOH and adding Zn2+ has been carefully investigated as well as the importance of the cellulose origin. We found consistent development that the dissolution occurs faster at higher concentrations of NaOH and with Zn2+ regardless the origin. Nevertheless, SAXS data show that materials with a larger amount of cellulose I show more apparent swelling in mesoscopic structure than bleached agricultural containing cellulose II. Despite few crystalline residues after the complete cooling-heating cycle shown by WAXS, some cellulose was not completely dissolved as some network structure remained in the samples under the test condition as suggested by SAXS.

Gas-specific adsorption capability of titanium dioxide and MXene nanocomposite thin films prepared by ultrasonic spray printing using inks oxidized at room temperature

The development of two-dimensional (2D) layered MXene materials has opened new possibilities for gas adsorption applications due to their high specific surface area, tunable surface chemistry, and excellent selectivity towards specific gases. These materials exhibit tremendous potential in adsorption-based gas separation and detection, particularly due to their strong interactions with target gas molecules, making them highly effective in gas removal and detection applications. However, currently available methods for synthesizing these oxidized nanocomposite inks are limited by the typically high temperatures involved. The present work addresses this issue by developing titanium dioxide and MXene (TiO2/Ti3C2 MXene) nanocomposite inks, where TiO2 nanoparticles are formed between the layers of the Ti3C2 MXene via oxidation in solution state under extended exposure in an oxygen rich atmosphere at room temperature. As a proof of concept, gas adsorption studies are conducted by applying the TiO2/Ti3C2 MXene nanocomposite inks onto gold-coated silicon wafers via an ultrasonic spray printing method. The gas adsorption results demonstrate that the TiO2/Ti3C2 MXene nanocomposites possess excellent adsorption selectivity toward methane and butane among alkane gases, and can achieve maximum adsorption capacities of 8.62 and 18.8 cm3/g, respectively. The results of ultrasonic spray printing quality tests conducted for different numbers of printed layers using the proposed TiO2/Ti3C2 MXene nanocomposite ink demonstrate that the film thickness can be regulated by controlling the number of printed layers, and the average thin film thickness remains only 0.313 μm for 10 printed layers. Meanwhile, the average roughness of the films resides between 0.130 μm (3 layers) and 0.220 μm (8 layers), which is uniformly and less than the average roughness of 0.225 μm measured for the original gold-plated silicon wafer. Hence, by employing facile ink-based printing techniques, such as ultrasonic spray printing, thin films with controlled thickness can be fabricated, thereby laying the foundation for their practical applications in environmental monitoring and industrial gas separation.

Regulatory mechanism of blending additives on interface interaction and phase separation of the heterogeneous braid-reinforced hollow fiber membranes

The exfoliation of the polymer layer from the reinforcement material is the key challenge for applying braid-reinforced hollow fiber membranes (BR HFMs). In this work, a mixed amphiphilic additive system was constructed and adopted in BR HFMs preparation by non-solvent induced phase separation (NIPS). The effect of the mixed system on the state of the casting solution and phase inversion process, the interaction between the casting solution and the braid material, together with the structure and filtration performance was studied. The role of the mixed system on the interface coordination and membrane structure formation mechanisms was elucidated. The results showed that both the composition of the mixed amphiphilic additives and the interaction time between the casting solution and braid material threw much light on the interface coordination and membrane formation. The interfacial compatibility of the casting solution and braid material was obviously improved, resulting in the enhancement of the binding force between the braid and PVDF membrane layer. The permeation flux and anti-exfoliation performance were simultaneously improved with the proper addition of the mixed amphiphilic additives. The stability of the BR HFMs was primarily testified by filtration of real sludge suspension solution with back-washing operation.

State discretization for continuous-state MDPs in infectious disease control

Repeated decision-making problems may arise in the health policy context, such as infectious disease control for COVID-19 and other epidemics. These problems may sometimes be effectively solved using Markov decision processes (MDPs). However, the continuous or large state space of such problems for capturing infectious disease prevalence renders it difficult to implement tractable MDPs to identify the optimal disease control policy over time. We therefore develop an algorithm for discretizing continuous states for approximate MDP solutions in this context. We benchmark performance against a uniform discretization using both a synthetic example and an example of COVID-19 in Los Angeles County.

The Role of Spacers as a Probe in Variation of Photoluminescence Properties of Mono- and Bi-Nuclear Boron Compounds.

A series of N,O donor-based mono- and binuclear four-coordinated boron complexes were synthesized. Depending on the substitution and spacer, these complexes exhibit intense blue, green and yellow emission in solution states. Notably, the fluorescence quantum yields (ΦF) and fluorescence decay (lifetime, τ) of mononuclear boron complexes (2 a-2 e) were higher than the binuclear boron complexes (2 f-2 k). The lowest lifetime and quantum yield in binuclear boron complexes were due to intramolecular rotation induced non radiative processes. The disulphide spacer-based boron complexes 2 i-2 k showed aggregation-caused quenching in the THF/H2O mixture whereas no other complexes were ACQ responsive. These complexes show large Stokes shift, one of them i. e. 2 e has the highest Stokes shift of 130 nm. Further, the electrochemical study suggests the presence of two redox incidences. Theoretical studies show close corroboration between the TD-DFT computed and experimentally measured absorption maxima as well as DFT (GIAO) calculated and experimentally measured 11B NMR values. This complements the appropriate selection of the theoretical methods to shed light on the electronic transitions in the mono- and binuclear BF2 complexes.

Corannulene‐Based Quintuple [6]/[7]Helicenes: Well‐Preserved Bowl Core, Inhibited Bowl Inversion and Supramolecular Assembly with Fullerenes

AbstractHerein, corannulene‐based quintuple [6]helicenes (Q[6]H‐1 and Q[6]H‐2) and [7]helicene (Q[7]H) were synthesized via penta‐fold Heck and Mallory reaction. Notably, Q[7]H represents the highest reported helicene based on corannulene. X‐ray crystallography reveals that Q[6]H‐2 adopts a propeller‐shaped conformation with a well‐preserved corannulene core, while Q[6]H‐1 and Q[7]H exhibit quasi‐propeller‐shaped conformations. Upon heating, conformer Q[6]H‐1 undergoes conversion to the thermodynamically more stable conformer Q[6]H‐2, whereas conformer Q[7]H remains unchanged due to larger steric congestion. Racemization of the enantiomer of Q[6]H‐1 and conformational conversion were observed simultaneously at elevated temperature, with DFT studies indicating a racemization barrier of 32.06 kcal ⋅ mol−1. In contrast, the racemization barrier for Q[6]H‐2 was calculated to be 45.46 kcal ⋅ mol−1, indicating exceptional chiral stability. Surprisingly, the bowl inversions of Q[6]H‐1 and Q[6]H‐2 conformers are somewhat inhibited by the helical blades, whereas this was not observed for other possible conformers of Q[6]H. These results first demonstrated that subtle conformational variations can lead to significant changes in chiral stability and bowl inversions of multiple helicenes. Due to the well‐preserved corannulene core, propeller‐shaped conformation and electron complementarity, Q[6]H‐2 can recognize fullerenes in both solution and solid state, which is a rare instance of co‐crystallization assembly between multiple helicenes and fullerenes.

Corannulene-Based Quintuple [6]/[7]Helicenes: Well-Preserved Bowl Core, Inhibited Bowl Inversion and Supramolecular Assembly with Fullerenes.

Herein, corannulene-based quintuple [6]helicenes (Q[6]H-1 and Q[6]H-2) and [7]helicene (Q[7]H) were synthesized via penta-fold Heck and Mallory reaction. Notably, Q[7]H represents the highest reported helicene based on corannulene. X-ray crystallography reveals that Q[6]H-2 adopts a propeller-shaped conformation with a well-preserved corannulene core, while Q[6]H-1 and Q[7]H exhibit quasi-propeller-shaped conformations. Upon heating, conformer Q[6]H-1 undergoes conversion to the thermodynamically more stable conformer Q[6]H-2, whereas conformer Q[7]H remains unchanged due to larger steric congestion. Racemization of the enantiomer of Q[6]H-1 and conformational conversion were observed simultaneously at elevated temperature, with DFT studies indicating a racemization barrier of 32.06 kcal ⋅ mol-1. In contrast, the racemization barrier for Q[6]H-2 was calculated to be 45.46 kcal ⋅ mol-1, indicating exceptional chiral stability. Surprisingly, the bowl inversions of Q[6]H-1 and Q[6]H-2 conformers are somewhat inhibited by the helical blades, whereas this was not observed for other possible conformers of Q[6]H. These results first demonstrated that subtle conformational variations can lead to significant changes in chiral stability and bowl inversions of multiple helicenes. Due to the well-preserved corannulene core, propeller-shaped conformation and electron complementarity, Q[6]H-2 can recognize fullerenes in both solution and solid state, which is a rare instance of co-crystallization assembly between multiple helicenes and fullerenes.

Alginate/Chitosan Complex Fibers Reinforcement and Their Mechanical Transition Continuum With Water Uptake Increasing.

Living tissues span a remarkable spectrum of modulus ranging from the level of Pa to GPa in a water-rich environment. Constructing soft and hard materials that match the mechanics of tissues and researching mechanical transition in water, are beneficial for their biological applications. Here, using polyelectrolyte complex fiber as a model system and reinforcing the fiber by stepwisely introducing additional coordination and covalent bonds, this investigated that the water effect on mechanical transition behaviors. Alginate/chitosan fiber (AC fiber) has a single electrostatic bond and shows continuous mechanical transition containing a glassy state, rubbery state, and terminal relaxation (initial modulus lower than 10MPa) in aqueous solution. Alginate/chitosan/calcium fiber (ACC fiber) has both electrostatic and coordination bonds, which shows the behavior of hard rubber (initial modulus 100MPa) when water reaches equilibrium. Alginate/chitosan/calcium/polydopamine fiber (ACCP fiber) with triple bonds, including electrostatic, coordination, and covalent bonds, exhibits the behavior like ductile plastics in aqueous solution (initial modulus 1000MPa). This work not only provides important insight into the toughening mechanism of polyelectrolyte complexes in water but also contributes to the preparation of tissue adaptive implantations.