Homogeneous System Research Articles

Corrolato(oxo)antimony(V) Dimer with Hydrogen-Bond Donor Groups in Secondary Coordination Sphere as a Catalyst for Hydrogen Evolution Reaction.

The focus is on developing alternative molecular catalysts using main-group elements and implementing strategic improvements for sustainable hydrogen production. For this purpose, a FB corrole with a (2-(2-((4-methylphenyl)sulfonamido)ethoxy)phenyl) group inserted into the meso position (C-10) of the corrole, along with its high-valent (corrolato)(oxo)antimony(V) dimer, was synthesized. In the crystal structure analysis of the FB corrole and the (corrolato)(oxo)antimony(V) dimer complex, it was noted that the sulfonamido group in the ligand periphery sits atop the corrole ring. The electrochemical hydrogen evolution reaction (HER) of the (corrolato)(oxo)antimony(V) dimer was studied and compared with a previously reported (corrolato)(oxo)antimony(V) complex, which lacks hydrogen-bond donor groups in the secondary coordination sphere. The newly designed molecules, featuring hydrogen-bond donor groups in the secondary coordination sphere, demonstrated clear superiority in the electrochemical HER. Controlled potential electrolysis was employed to evaluate the charge accumulation associated with hydrogen generation in a homogeneous three-electrode system in the presence of 50 mM TFA. The produced hydrogen exhibits a Faradaic efficiency of approximately 80.96%, a turnover frequency (TOF) of 0.44 h-1, and a production rate of 52.83 μL h-1, highlighting the effective catalytic activity of the (corrolato)(oxo)antimony(V) dimer in hydrogen evolution.

Microstructure and characteristics of phase-separated gels of Type-A gelatin and hydroxypropyl starch: pH responsiveness

The impact of phase separation behavior on the performance of hydrogels has always been the research focus. This study explored the relationship of “pH-microstructure-hydrogel properties” of phase-separated hydrogels composed of type-A gelatin (GE, 5 wt%) and hydroxypropyl starch (HPS, 3 wt%). The results revealed that changes in the microstructure of the hydrogel at different pHs significantly impacted the gel properties. At pH 4.00 and 11.00, phase separation occurred in the GE/HPS gel with a microstructure of HPS-in-GE. In particular, at pH 5.00, 6.00, 7.00, and 9.00, severe phase separation resulted in the separation of substantial aggregates of HPS and GE, resulting in a continuous phase structure. At pH 2.00 and 3.00, phase separation was suppressed, resulting in a homogeneous microstructure. Compared to the phase-separated gels at pH 4.00–11.00, the homogeneous systems at pH 2.00 and 3.00 displayed a synergistic effect with higher gel strength. Analysis of intermolecular forces in the GE/HPS gel indicated that hydrogen bonding was the primary interaction force. Furthermore, the addition of GE/HPS into hawthorn jelly at about pH 3.00 effectively preserved the structural appearance and exhibited higher levels of hardness, thus improving the sensory properties of hawthorn jelly. In summary, phase separation decreased the storage modulus of GE/HPS gel, but the compatibility of GE/HPS macromolecules exhibited synergistic effects at 2.00 and 3.00 and improved the hydrogel mechanical properties. This work provides some new insights for GE/HPS-based gel foods.

Collective behavior of active filaments with homogeneous and heterogeneous stiffness.

The collective dynamics of active biopolymers is crucial for many processes in life, such as cellular motility, intracellular transport, and division. Recent experiments revealed fascinating self-organized patterns of diverse active filaments, while an explicit parameter control strategy remains an open problem. Moreover, theoretical studies so far mostly dealt with active chains with uniform stiffness, which are inadequate in describing the more complicated class of polymers with varying stiffness along the backbone. Here, using Langevin dynamics simulations, we investigate the collective behavior of active chains with homogeneous and heterogeneous stiffness in a comparative manner. We map a detailed non-equilibrium phase diagram in activity and stiffness parameter space. A wide range of phase states, including melt, cluster, spiral, polar, and vortex, are demonstrated. The appropriate parameter combination for large-scale polar and vortex formation is identified. In addition, we find that stiffness heterogeneity can substantially modulate the phase behaviors of the system. It has an evident destructive effect on the long-ranged polar structure but benefits the stability of the vortex pattern. Intriguingly, we unravel a novel polar-vortex transition in both homogeneous and heterogeneous systems, which is closely related to the local alignment mechanism. Overall, we achieve new insights into how the interplay among activity, stiffness, and heterogeneity affects the collective dynamics of active filament systems.

Wave Speeds for a Time-Periodic Bistable Three-Species Lattice Competition System

In this paper, we consider propagation direction (which can be used to predict which species will occupy the habitat or win the competition eventually) of a bistable wave for a three-species time-periodic lattice competition system with bistable nonlinearity, aiming to address an open problem. As a first step, by transforming the competition system to a cooperative one, we study the asymptotic behavior for the bistable wave profile and then prove the uniqueness of the bistable wave speed. Secondly, we utilize comparison principle and build up two couples of upper and lower solutions to judge the sign of the bistable wave speed which partially provides the answer to the open problem. As an application, we reduce the time-periodic system to a space–time homogeneous system, we obtain the corresponding criteria and carry out numerical simulations to illustrate the availability of our results. Moreover, an interesting phenomenon we have found is that the two weak competitors can wipe out the strong competitor under some circumstances.

Multifunctional property of N,N-bis (carboxymethyl) glutamic acid modified biomass material: adsorption and degradation removals of cationic dyes in wastewater

As a common type of pollutants in industrial wastewater, cationic dyes have attracted great attentions. Using biodegradable N,N-di (carboxymethyl) glutamic acid (GLDA) as ligand and corn stalk (CS) as matrix, a novel and green biomass modified material GLDA-CS was successfully prepared. The multifunctional property of GLDA-CS for removing methylene blue (MB), malachite green (MG) and alkaline red 46 (R-46) from wastewater was evaluated. The dyes were removed by the electrostatic adsorption based on the cationic adsorption properties of GLDA-CS. The removal rates of MB, MG and R-46 can quickly reach 90.4%, 96.8% and 94.8% in short time. especially for MG and R-46 even only 20 min. The adsorption capacities of the dyes still remain more than 86.5% of the initial values after 5 cycles. In a heterogeneous system, the dyes were removed by Fenton-like degradation based on the metal chelating property of GLDA-CS. 100% degradation rates of the dyes can be achieved in 35 min under the acidic region. Even if at pH 7, degradation rates are 44.1%, 47.1% and 56.6% higher than those under the conventional homogeneous system, and the degradation rate remained at 83.7% after 5 cycles. Regardless of the adsorption or degradation, GLDA-CS shows strong anti-anion interference ability. The potential mechanisms of adsorption and degradation for the dyes by GLDA-CS were deduced by quantization calculation. It is concluded that the adsorption removal of the dyes by GLDA-CS follows MG > R-46 > MB, and mainly depends on the electrostatic interaction between -COOH in GLDA-CS and -N- in the dye molecules. Based on the degradation mechanism of Fenton-like reaction, the possible active sites of the dyes attacked by free radicals and their possible degradation intermediates were predicted by the calculations of Fukui function.

Enzymatic reaction and competitive prereduction enable label-free and separation-free inductively coupled plasma mass spectrometry detection of leukemia cells

The enzyme terminal deoxynucleotidyl transferase (TdT) exhibits significant activity in various leukemia cells, including human acute lymphoblastic leukemia cells (CCRF). It demonstrates substantial potential as a diagnostic biomarker for acute lymphoblastic leukemia (ALL). Herein, a highly sensitive method for the homogeneous quantification of TdT and CCRF cells, without the need for labeling or separation, was established based on inductively coupled plasma mass spectrometry (ICP-MS). The simple sensor relied on the TdT-induced polymerization process, lengthening the DNA strand and producing large amounts of the by-product phosphates of pyrophosphate (PPi). The PPi formed complexes with Cu²⁺, altering its morphology in homogeneous systems. The remaining Cu²⁺ competed with Hg²⁺ in consuming ascorbic acid (AA) through the pre-reduction of Hg²⁺, affecting the ICP-MS signal of Hg²⁺. Under optimal conditions, this approach exhibited excellent specificity and ultrahigh sensitivity, with limits of detection (LODs) as low as 0.05 U/L for TdT and 5 cells/mL for CCRF cells, respectively. The proposed method offers significant advantages, including high sensitivity and precision, operation at room temperature without the involvement of proteases, and the ability to accurately quantify in complex biological matrices. Consequently, the proposed method shows great promise as a valuable tool for TdT-related biological research and leukemia diagnosis.

Методика перетворення кодових послідовностей у відповідності до системи координат модуляційного диска

An analysis of current approaches used in the design of optical recording systems for modulation disks has been conducted. By adapting mathematical models, software algo-rithms were developed to transform code sequences represented in polar, homogeneous, and parametric coordinate systems, and the unique characteristics of each approach in de-veloping a universal method for ensuring accurate and efficient modulation pattern trans-formation were established. It was noted that the polar coordinate system is the most suit-able for practical applications in code sequence transformations. Its ability to effectively represent circular and symmetrical structures, as well as the convenient representation of objects with radial symmetry, provides advantages in the creation of modulation disks. As a result of the study, effective software solutions for automating data processing in the formation of modulation patterns were identified. The implementation of the developed software algorithms for the presented approach involves adapting the code sequence to the current metric within the design of an optical system based on modulation disks. The pre-sented methodology ensures the ability to transform code sequences regardless of the cho-sen coordinate system, which significantly enhances its flexibility and versatility for prac-tical applications.

A Versatile Method to Create Antibody/Split‐Enzyme Complexes and Its Application to a Rapid, Homogeneous, and Universal Electrochemical Immunosensing System

AbstractIn this study, a versatile method is developed to create an antibody/split‐enzyme complex for use in electrochemical immunosensors. SpyCatchers are genetically fused at each terminus of flavin adenine dinucleotide‐dependent glucose dehydrogenase (FAD‐GDH) and a protease recognition sequence is inserted into a loop region to prepare a soluble protein and the split GDH. SpyTag‐fused single‐chain variable fragments (scFvs) are employed, which leads to the simple preparation of antibody‐split enzyme complexes (split AECs). The addition of pentameric C‐reactive protein (CRP), as a representative multimeric protein, restored the GDH activity of the split AECs, as the two split AEC fragments formed active GDH when in close proximity. CRP in human serum is electrochemically detected within 5 min without any washing steps with a clinically relevant CRP detection range (0.03–1 mg dL−1). The detection system is expanded to detect hemoglobin, SARS‐CoV‐2 spike protein, and inactivated SARS‐CoV‐2 by exchanging the scFvs. These results show that the convenient preparation method of the split GDH and the split AEC by the insertion of the protease recognition sequence and the use of SpyCatcher/SpyTag can realize a rapid, homogeneous, and universal electrochemical detection system that can be integrated into a commercially available electrochemical glucose sensor.

Existence and Uniqueness of Homogeneous Linear Equation Solutions in Supertropical Algebra

This research investigates the existence and uniqueness of solutions to homogeneous linear equations in supertropical algebra. We analyze the structure of supertropical matrices to identify the conditions in which nontrivial solutions exist for the system of equations A⊗𝒙 ⊨ 𝜀, where A is a matrix over a supertropical semiring and x is a vector. By applying determinant-based criteria, we demonstrate how tropical and supertropical values influence the solution space. The research applies theorems that determine the presence of trivial and nontrivial solutions and uses examples to illustrate practical methods for solving homogeneous matrix systems. This highlights the distinct characteristics of supertropical algebra compared to classical linear algebra. Our findings provide a deeper insight into solution behaviors in supertropical systems, paving the way for further research in tropical mathematics.

Robust finite-time output feedback stabilisation for a class of uncertain planar systems with asymmetric output constraints

This paper considers the finite-time output feedback stabilisation (FTOFS) problem for a class of uncertain planar systems with asymmetric output constraints. The presence of unknown control coefficients, unknown measurement sensitivity and asymmetric output constraints makes the system under consideration essentially different from those in the existing related works. By constructing a new barrier Lyapunov function and applying homogeneous system theory, a simple proportional-derivative like finite-time output feedback controller is explicitly constructed, which only utilises the output information. A rigorous proof demonstrates that not only the closed-loop system is finite time stable, but also the requirement of asymmetric output constraint can be achieved. The novelty of the control approach lies in that it is capable to handle the FTOFS problem for uncertain planar systems with or without asymmetric output constraints in a unified manner, without changing the control structure. The efficiency of the proposed theoretical results are confirmed by simulation results.

Relaxation RKN-type integrators that preserve two invariants for second-order (oscillatory) systems

Recently, the relaxation technique has been widely used to impose conservation of invariants while retaining the full accuracy of the original method. So far, only a single invariant of a system has been considered. In this work, by a mild generalization of the relaxation technique, the Runge–Kutta–Nyström (RKN) integrators are modified to preserve two invariants for second-order system of Ordinary Differential Equations (ODEs). The proposed integrators can be explicit and of arbitrarily high order. The accuracy of the relaxation RKN integrators and the existence of valid relaxation parameters have been proved. The construction of the new integrators is under the framework of adapted RKN (ARKN) integrators which are specially designed for numerical solving second-order oscillatory systems. Therefore, the proposed integrators could be oscillation-preserving in the sense that they exactly integrate homogeneous oscillatory system q′′+Kq=0. Some numerical experiments are conducted to show the advantage and efficiency of the proposed integrators in comparison with the standard (A)RKN integrators.

Exact solution of the generalized Riemann problem for the Eulerian droplet model with particle pressure

In this paper, we investigate the generalized Riemann problem for the Eulerian droplet model with particle pressure. By introducing two new state variables, the generalized Riemann problem for a system of balance law (nonhomogeneous system) is neatly transferred into the Riemann problem for a system of conservation law (homogeneous system). Four different kinds of exact solutions are presented in fully explicit forms, which are given in terms of two nonconstant states separated by a shock or a generalized rarefaction wave or by a combination of such wave profiles.

Families of exact similaritons with flexible modulations in N-coupled homogeneous and inhomogeneous systems

In this paper, a family of exact solutions to N-coupled nonlinear Schrödinger (N-CNLS) equations including bright and dark solitons, Akhmediev breathers, Kuznetsov-Ma breathers, and rogue waves are derived with the aid of a generic nonlinear wave assumption. As an application of the solutions, we present a scheme to realize amplitude coding in an identical waveguide system. Furthermore, by a general self-similar transformation method, exact controllable similaritons of N-coupled inhomogeneous NLS (N-CINLS) equations are constructed under relaxed compatibility conditions. Flexible modulations of similaritons are investigated in a typical inhomogeneous system. Based on the general self-similar transformation, we further study various and novel modulations of composite similariton of 2-CINLS regimes. The various similaritons presented here may be expected to find application in the control and transmission of nonlinear waves in realizable complex systems including those based on optical fibers and Bose-Einstein condensates.

Stabilization of gels and emulsions in the ternary water/eugenol/poloxamer 407-system: Physicochemical characterization and potential application as encapsulation platforms

The ternary system water/eugenol/poloxamer 407 can form a variety of phases that are strongly influenced by the mixture composition and the thermal history of the system. In this study, we investigated the stabilization of emulsion and gel-like systems in which eugenol is encapsulated in a poloxamer 407 matrix. Our results reveal the complex interplay between poloxamer 407 and eugenol compositions in the stabilization single-phase systems at 25ºC. Increasing concentrations of poloxamer were found to incorporate higher amounts of eugenol into emulsion-like dispersions, effectively preventing coalescence and Ostwald ripening. However, high concentrations of poloxamer 407 induced gelation of these dispersions, resulting in eugenol-loaded poloxamer 407 gels. The thermal annealing of the emulsions at 65°C for 1 h followed by equilibration at room temperature allows the extension of the compositional range for the formation of homogeneous single-phase systems providing a strategy to modulate the phase diagram of the ternary system. Additionally, the encapsulation of hydrophobic pesticides in gel-like matrices was investigated, showing uniform distribution and consistent loading capacity (approximately 0.70 % w/w) across different pesticides which may contribute to facilitate the environmental distribution and efficacy of the encapsulated molecules. This research highlights the potential of eugenol/poloxamer 407-based systems as an environmentally friendly platform for the encapsulation and delivery of hydrophobic active molecules, offering a versatile solution for various applications.

Correlation of surface properties with dissolution behavior of amorphous solid dispersion of Riluzole and its pharmacodynamic evaluation

Formulation of amorphous solid dispersion (ASD) of any poorly water-soluble drug is among the most promising techniques to increase the dissolution profile of drug and hence its bioavailability. Various literatures give evidences of the role of drug-polymer interactions in the ASD systems, very little information is available about the surface properties of the drug molecule and their ASDs which contributes to a higher dissolution profile. Current work focuses on exploring the surface behavior of a poorly water-soluble drug Riluzole (RLZ) and its ASDs prepared with two highly hydrophilic polymers, polyacrylic acid (PAA), and polyvinylpyrrolidone vinyl acetate (PVP VA). Initial characterization using X-ray diffraction (XRD) revealed about the weight fraction of drug required to prepare a single-phase homogenous system with both the polymers. The saturation solubility and the dissolution studies showed an increase in RLZ solubility as well as the dissolution profile due to the presence of polymers. The role of polymers in changing the surface properties in terms of wettability and polarity were explored using contact angle method and X-ray photon spectroscopy (XPS). Additionally, the neuroprotective efficacy and dose dependent hepatotoxicity were also evaluated in male wistar rats. These studies confirmed the increase in the surface polarity and hence the enhanced ability of ASD formulations to interact with water. The in vivo studies indicated that at the current recommended dose the efficacy as well as toxicity is increased for the ASD formulation. Hence, this formulation can be given at a lower dose to achieve same therapeutic effect with lower toxicity.

Recent Advances in Heterogeneously Catalyzed Acceptorless Dehydrogenation of Alcohols to Carbonyl Derivatives and N-heterocyclic Compounds

: Oxidation of alcohols in an oxidant-free condition, commonly known as the acceptorless dehydrogenation (AD) reaction, has recently emerged as one of the widely used processes in synthetic organic chemistry. Alcohol acts as an excellent chemical precursor that produces a variety of dehydrogenated value-added products such as carbonyls, acids, acetals, and several coupling products, followed by the concomitant evolution of molecular hydrogen gas. AD reaction of alcohol, therefore, can be considered as a vital reaction for the hydrogen economy using alcohols as a liquid hydrogen carrier. Over the past decade, the growing importance of AD reactions has set the way for the continuous development of various homogeneous and heterogeneous catalytic systems. With the advantage of reusability and recyclability, heterogeneous catalysts have now become more promising and significant in the catalytic domain. This review aims to make an overview of the transition metal-based heterogeneous catalytic system of acceptorless alcohol dehydrogenation reaction reported till December, 2023.

Homogeneous continuous flow nitration of O-methylisouronium sulfate and its optimization by kinetic modeling.

Nitration of O-methylisouronium sulfate under mixed acid conditions gives O-methyl-N-nitroisourea, a key intermediate of neonicotinoid insecticides with high application value. The reaction is a fast and highly exothermic process with a high mass transfer resistance, making its control difficult and risky. In this paper, a homogeneous continuous flow microreactor system was developed for the nitration of O-methylisouronium sulfate under high concentrations of mixed acids, with a homemade static mixer eliminating the mass transfer resistance. In addition, the kinetic modeling of this reaction was performed based on the theory of NO2 + attack, with the activation energy and pre-exponential factor determined. Finally, based on the response surface generated by the kinetic model, the reaction was optimized with a conversion of 87.4% under a sulfuric acid mass fraction of 94%, initial reactant concentration of 0.5 mol/L, reaction temperature of 40 °C, molar ratio of reactants at 4.4:1, and a residence time of 12.36 minutes.

Synergistic Degradation of Methylene Blue by Hydrodynamic Cavitation Combined with Hydrogen Peroxide/Vitamin C System.

In this study, a new combined process of hydrodynamic cavitation (HC) and a hydrogen peroxide/vitamin C (H2O2/Vc) system was proposed for the degradation of methylene blue (MB) in wastewater. An impact-jet hydraulic cavitator was used as the cavitation generation equipment, and H2O2/Vc was selected as a homogeneous oxidation system. The degradation characteristics of MB were investigated. The results showed that the degradation effect of HC in combination with the H2O2/Vc system was more effective than that of the individual HC or H2O2/Vc system. A maximum degradation rate of 87.8% was achieved under the following conditions: H2O2 concentration of 0.03 mol/L, Vc concentration of 0.021 mol/L, inlet pressure of 0.3 MPa, initial solution concentration of 4 μmol/L, solution volume of 150 mL, and reaction time of 10 min. The synergy index was 1.615, indicating a synergistic effect between the HC and H2O2/Vc system. The data of the hydroxyl radical (·OH) yield under the conditions of HC, the H2O2/Vc system, and the HC + H2O2/Vc system were fitted and analyzed. A correlation equation for ·OH yield was established, further revealing the synergistic mechanism of the HC and H2O2/Vc system. The intermediate products of MB degradation were detected based on LC-MS, and three possible degradation pathways of MB degradation were proposed. The combined process of HC and H2O2/Vc systems exhibited relatively low energy efficiency and operating cost, indicating that it was in line with the development direction of wastewater treatment.

On ( Semi Homogeneous Systems of Differential Equations

مفهوم التجانس في المعادلات التفاضلية يمكن ان يعمم على أنظمة المعادلات التفاضلية، حيث تم في هذا العمل عرض تصنيف لأنظمة المعادلات التفاضلية ثلاثية الأبعاد بناءً على تعريف مصفوفة الجاكوبيان ومحدداتها، حيث تم تعريف نظامين من النظام المتجانس ، ويسمى النظام شبه المتجانس من النمط , والنظام الاخر شبه المتجانس من النمط , حيث اعتمد التعريف الأول على مصفوفة الجاكوبيان ، بينما اعتمد الثاني على محدد المصفوفة الجاكوبية . وتم تقديم أمثلة على كلا التعريفين، ودراسة العلاقة بينهما. بالإضافة إلى إيجاد معادلات لهذين التعريفين، وقد تم أيضًا إثبات بعض النتائج لهذين التعريفين.

Paraxial reconstruction: conversion of homogeneous lens forms to continuous gradient-index media

We present a technique for the optical design of generalized-distribution GRIN lenses. Multi-element homogeneous lens designs are reconstructed as single GRIN media via smoothing of the homogeneous lens paraxial ray paths. These continuous optical systems successfully replicate the first-order properties of their homogeneous parent lens systems and serve as starting points for further optimization. When the technique is applied at several wavelengths, the chromatic aberration correction of the homogeneous parent lens is also converted. The paraxial reconstruction, finite-ray optimization, and evaluation of several lens designs are demonstrated.