Strong Interaction Research Articles

EFFECTS OF THE CLIMATE GRADIENT ONF THE WOOD DENSITY OF Cedrela odorata L. IN THE NEOTROPICAL REGION

Understanding wood properties is crucial for optimizing its technological potential, enhancing both the effectiveness of use and product quality. Among these properties, density is regarded as one of the most significant. Numerous studies have documented the relationship between wood density and climate. However, the influence of climatic factors on the density variation of native species remains largely unexplored. Cedrela odorata L., a species traditionally logged in Brazil and widely distributed across the Neotropical region, requires further analysis to understand its potential response to varying climate patterns, thereby informing its management. This study aimed to determine the relationship between the basic density of Cedrela odorata L. and the climatic conditions in the Neotropical region. A comprehensive database was compiled from published scientific literature. Statistical analyses were conducted using Generalized Linear Models (GLM), with the best models selected based on the corrected Akaike Information Criterion (AICc). The presence of spatial patterns was assessed using Moran’s Index to verify spatial autocorrelation. The study identified significant relationships between the wood density of C. odorata and variables such as mean annual temperature and annual precipitation. The findings indicate a strong interaction between the climatic variables analyzed and the basic density of Cedrela odorata L. wood, with density being more sensitive to mean annual temperature.

High-strength and toughness CNT films from microwaving-promoted purification and structural reconstruction

Carbon nanotube (CNT) films can now be prepared by catalytic floating chemical vapor deposition (CVD) with low cost and high yield. However, their performance deteriorates drastically due to the presence of impurities and structural defects all over the films. In this study, we report a simple and fast heating and quenching approach to tackle this issue by using a household microwave oven. Experimental results show that the strong interaction between CNTs and low-power microwaves within 10 s not only triggered the diffusion of Fe particles from the interior to the surface of the film for easy purification but also improved the graphitic structure of CNTs and their inter-tube binding for mechanical strengthening and electrical conduction. After a sequential treatment of microwaving-acid washing-microwaving, followed by additional rolling, the final CNT film exhibited a tensile strength of 7.45 GPa, an elongation at break of 11.33 %, and an electrical conductivity of 1.85 × 106 S m−1. The combination of such mechanical and electrical properties is superior to previous fibers and films reported in open literature. Considering its efficient and environment-friendly features, the present approach is suitable for the large-scale production of high-performance CNT films, thereby meeting the requirements for practical applications in many fields.

The Potential of Clove (Syzygium aromaticum) Essential Oil as Sunscreen and Anti-Aging Agents: An In Vitro and In Silico Study

The earth thermal conditions increase exposure to sunlight, triggering skin damage. The skin has defense mechanisms but needs additional protection to prevent photoaging. Using sunscreen is an effort to reduce the harmful effects of sun exposure. Natural ingredients with antioxidant activity can be developed into sunscreen and antiaging products, including cloves. This study aims to assess the antioxidant, sun protection, and anti-aging properties of essential oils derived from clove leaves and buds. The antioxidant activity was assessed by the DPPH system and then formulated into 5 and 10 % clove leaves cream, as well as 5 and 10 % clove bud cream. The SPF values were assessed using a spectrophotometer and the Mansur formula. The antiaging potential was assessed using the in silico method with MMP-1 protein employing the Auto Dock Vina software, followed by analysis and visualization using BIOVIA Discovery Studio. The essential oils from clove leaves and buds have DPPH IC50 values of 23.09 and 30.31 ppm. The SPF values of clove leaves essential oil, 5 % leaves cream, and 10 % leaves cream are 38.61, 14.32, and 22.15. Meanwhile, the SPF values of clove bud essential oil, 5 % bud cream, and 10 % bud cream are 38.19, 9.32, and 18.16. The in silico test revealed that caryophyllene, eugenol, humulene, and phenol, 2-methoxy-4-(2-propenyl), acetate) have strong interactions because they can interact with the active site of proteins using hydrogen, hydrophobic, and van der Waals bonds. The essential oils from clove leaves and buds exhibit very strong antioxidant activity and offer ultra-protection as a sunscreen. The cream formulations still exhibit sunscreen activity, albeit at a lower level compared to pure essential oil. Caryophyllene, eugenol, humulene, and phenol, 2-methoxy-4-(2-propenyl)-, acetate), have potential as antiaging agents, as indicated by their binding affinity and chemical bond interactions observed in the in silico test. HIGHLIGHTS Clove buds and leaves exhibit antioxidant properties. Essential oil from clove buds and leaves demonstrates a substantial Sun Protection Factor (SPF). The compounds contained in clove essential oil exhibit promise as prospective agents in anti-aging applications. GRAPHICAL ABSTRACT

A polyhedron-based metal-organic framework with electronegative donor sites for efficient C2H6/C2H4 separation

Ethylene is an important chemical raw material which is widely used in the production of chemical fibers, plastics, rubber, coatings, as well as medicines, and its separation from the gas mixtures of C2H6/C2H4 is of great importance but a challenging task due to their similar physical properties and molecular dimensions. Herein, we report the C2H6 and C2H4 sorption studies on a robust anionic metal-organic framework (MOF) {(NH2Me2)[Co3(μ3OH)(TPT)(TZB)3](H2O)6(DMA)6}n (Co-MOF) formed by connection of Co3(OH) clusters by two N-rich organic ligands 2,4,6-tri(4-pyridyl)-1,3,5-triazine (TPT) and 4-(1H-Tetrazol-5-yl)benzoic acid (H2TZB). The prepared Co-MOF features a polyhedron stacking network structure composed of trigonal bipyramidal cages and octahedral cage which both contribute to a high C2H6 uptake capacity of 6.48 mmol/g and a decent C2H6/C2H4 selectivity of 1.54 at 298 K and 1 bar. Grand Canonical Monte Carlo (GCMC) simulation results agree well with the experimental tendency, both in the adsorption isotherms and sorption heats, which demonstrated that the suitable pore surfaces with electronegative donor sites generated multiple CH ⋅⋅⋅O/N and CH ⋅⋅⋅π interactions between the framework and C2H6, resulting in a stronger interaction between the MOF skeleton and C2H6 molecule than C2H4 as reflected by the dispersion-corrected density functional theory (DFT) calculation.

Quantum Entanglement between Optical and Microwave Photonic Qubits

Entanglement is an extraordinary feature of quantum mechanics. Sources of entangled optical photons were essential to test the foundations of quantum physics through violations of Bell’s inequalities. More recently, entangled many-body states have been realized via strong nonlinear interactions in microwave circuits with superconducting qubits. Here, we demonstrate a chip-scale source of entangled optical and microwave photonic qubits. Our device platform integrates a piezo-optomechanical transducer with a superconducting resonator which is robust under optical illumination. We drive a photon-pair generation process and employ a dual-rail encoding intrinsic to our system to prepare entangled states of microwave and optical photons. We place a lower bound on the fidelity of the entangled state by measuring microwave and optical photons in two orthogonal bases. This entanglement source can directly interface telecom wavelength time-bin qubits and gigahertz frequency superconducting qubits, two well-established platforms for quantum communication and computation, respectively. Published by the American Physical Society 2024

In-Silico ADMET Prediction, Structure-Based Drug Design and Molecular Docking Studies of Quinazoline Derivatives as Novel EGFR Inhibitors

This Present research provides valuable insights and implications for the development of quinazoline derivatives as novel EGFR inhibitors. The in-silico ADMET predictions indicate that the quinazoline derivatives possess promising drug-like properties, suggesting their potential for further development as oral drugs. The low risk of toxicity and favorable metabolic and excretion profiles enhance their suitability for therapeutic applications Molecular docking studies revealed strong binding interactions between the quinazoline derivatives and the EGFR kinase domain. These interactions suggest that these compound shave the potential to effectively inhibit EGFR activity, making them promising candidates for anti- cancer drug development to progress from in-silico findings to clinical applications, further research is essential. Future work should encompass in vitro and in vivo experiments to validate the inhibitory potential of these compounds against EGFR. Additionally, pharmacokinetic studies are warranted to confirm their ADMET properties. Structural optimization through medicinal chemistry approaches may further enhance their binding affinities and specificity for EGFR. It represents a pivotal step in the exploration of quinazoline derivatives as novel EGFR inhibitors. The combined efforts in ADMET prediction, structure-based drug design, and molecular docking have provided a strong foundation for the development of innovative anti-cancer therapies. The potential of these compounds to target EGFR, a crucial player in various cancers, holds great promise for improving the treatment options available to patients and advancing the field of oncology.

Modeling the Time Evolution of Compact Binary Systems with Machine Learning

This work introduces advanced computational techniques for modeling the time evolution of compact binary systems using machine learning. The dynamics of compact binary systems, such as black holes and neutron stars, present significant nonlinear challenges due to the strong gravitational interactions and the requirement for precise numerical simulations. Traditional methods, like the post-Newtonian approximation, often require significant computational resources and face challenges in accuracy and efficiency. Here, we employed machine learning algorithms, including deep learning models like long short-term memory (LSTM) and temporal convolutional network (TCN), to predict the future evolution of these systems based on extensive simulation data. Our results demonstrate that employing both LSTM and TCN even as black-box predictors for sequence prediction can also significantly improve the prediction accuracy without physics-informed neural networks (as partial differential equation solvers with prior knowledge or inductive bias. By employing LSTM and TCN, we obtained R 2 values of 99.74% and 99.19% for the evolutionary orbits of the compact binaries data set, respectively. Our models demonstrate the ability to effectively capture the dynamics of the binaries, achieving high prediction performance with significantly reduced computational overhead by a factor of 40, compared to conventional numerical methods. This study paves the way for more effective and computationally scalable approaches to the understanding of gravitational phenomena and predictive modeling in gravitational-wave astronomy.

Molecular Docking Insights into Gatifloxacin Derivatives as Prospective Antidepressant Agents

ABSTRACT: The current focus in drug discovery aims to identify promising therapeutic candidates for further research. Depression, a significant public health issue, is closely linked to low serotonin levels. Researchers are investigating novel antidepressant agents through chemical modifications and protein analysis. The various derivatives are assessed for their antidepressant activity through in silico molecular docking simulations by using AutoDock and ADME analysis. Autodock includes formation of PDBQT files, docking of converted ligands and protein forms, formation of 9 different positions of docked molecules results into binding score, 2D image and 3D images of same one. Docking studies reveal molecular interactions between biological macromolecules (8FSB) and ligands, with strong protein-ligand interactions potentially inhibiting the reuptake of serotonin at the post-synaptic nerve, thereby increasing serotonin availability and exerting antidepressant effects. Gatifloxacin derivatives demonstrated higher binding affinities with 8FSB, Gati I (-11.4 kcal/mol), Gati II (-11.1 kcal/mol), Gati III (-8.2 kcal/mol), Gati IV (-7.9 kcal/mol), Gati V (-9.5 kcal/mol), and Gati VI (-9.7 kcal/mol), all exceeding gatifloxacin (-6.9 kcal/mol). These findings suggest that gatifloxacin derivatives may serve as potent antidepressants of drug discovery lies in the synergistic use of in vitro and in vivo studies, leveraging technological advancements to develop safer and more effective therapies. The findings related to gatifloxacin derivatives highlight the potential of these approaches in identifying novel antidepressants, paving the way for further research and clinical trials.

Lignin-modified cellulose nanofibers hydrogel under adjustable binary solvent systems with excellent adhesion, self-healing and anti-freeze properties

Hydrogels with remarkable flexibility have gained popularity as materials for current research. However, the unfavorable properties of short-term adhesion, susceptibility to damage, and freezing in low-temperature presented by conventional hydrogels have become bottlenecks for further applications. In this work, an anti-freezing hydrogel with excellent mechanical, adhesion, and self-healing properties were developed by constructing a persistent semiquinone/quinone-catechol redox equilibrium environment. The introduction of lignin-modified cellulose nanofibers (LCNFs) significantly improved the overall mechanical properties of the material, driven by strong hydrogen bond interactions. This enhancement was evident in the tensile properties (97.74 ± 1.72 kPa, 783 %) and compression properties (> 90 %). Within the internal network of the gel, the synergistic action of lignin and ammonium persulfate resulted in the production of catechol, which imparted the gel with excellent adhesion properties (28.26 ± 2.13 KPa) and broad adhesion applicability. In addition, the incorporation of ethylene glycol (EG) positively contributed to the strengthening of the gel while endowed with tunable anti-freezing properties. Given the exceptional advantages of the prepared hydrogels, they were used to assemble flexible strain sensors with outstanding sensitivity for monitoring human motions.

Design, Synthesis, Computational Study, and Biological Evaluation of Sulfonyl Tethered Piperazine Derivatives as Antimicrobial Agents

AbstractPiperazine, a nitrogen‐containing heterocyclic compound, has potential in medical chemistry due to its versatile structure and ease of modification. Therefore, researchers have designed novel piperazine derivatives with various biological activities, including antiviral, antibacterial, and antifungal properties. In this study, a new series of 2‐(4‐((5‐bromo‐2‐methoxyphenyl)sulfonyl) piperazine‐1‐yl) acetamide derivatives (7a‐l) were synthesized and their structures were identified using 1H‐NMR, 13C‐NMR, and HRMS spectroscopic methods. The in vitro antimicrobial activity of these compounds was tested against four bacterial strains and two fungi strains. Some of the sulfonyl piperazine derivatives (7d, 7e, 7f, 7j, 7k, and 7l) exhibited relatively good antimicrobial and antifungal activities compared to standard drugs. Further analysis using computational docking confirmed strong binding interactions, aligning with our results. Our compounds exhibited improved potency compared to existing standard treatments.

Optimization design and performance study of magnesium alloy vascular clamp

Purpose: This study investigates the effects of varying inner diameter of a vascular clamp made from an Mg–Nd–Zn–Zr alloy on its functional performance. The primary objectives are to optimize the clamp’s structure, assess its performance across different inner diameters, and ultimately determine the optimal configuration. Methods: We developed a V-shaped vascular clamp equipped with a locking mechanism and transverse teeth. The study involved comparing vascular clamps with various inner diameters (0.35 mm, 0.4 mm, 0.5 mm and 0.6 mm, denoted as R0.35, R0.4, R0.5 and R0.6, respectively), achieved by modifying the clamp design. Finite element analysis simulated the closure process of these clamps, both with and without blood vessels, to analyze stress and strain distribution. Subsequently, we manufactured a clamp with the optimized design and conducted performance evaluations, including a closing strength test and an in vitro immersion test. Results: Among the tested vascular clamps, the R0.5 clamp demonstrated the lowest strain (0.50798) and minimal stress on blood vessels (0.7629 MPa). Notably, the R0.5 clamp remained intact during clamping fracture experiments and demonstrated a maximum closing force of 334.98±15.4 mmHg. Regarding corrosion resistance, the clamped position showed a higher corrosion rate (0.179±0.00551 mg.cm-2.day-1) compared to the open clamp (0.161±0.00306 mg.cm-2.day-1). Conclusion: The R0.5 clamp demonstrated superior performance in finite element analysis, showing effective vascular closure, strong clamping force, and uniform corrosion behavior. Overall, these results highlight its potential as an effective tool for vascular closure.

Investigation into the Simulation and Mechanisms of Metal-Organic Framework Membrane for Natural Gas Dehydration.

Natural gas dehydration is a critical process in natural gas extraction and transportation, and the membrane separation method is the most suitable technology for gas dehydration. In this paper, based on molecular dynamics theory, we investigate the performance of a metal-organic composite membrane (ZIF-90 membrane) in natural gas dehydration. The paper elucidates the adsorption, diffusion, permeation, and separation mechanisms of water and methane with the ZIF-90 membrane, and clarifies the influence of temperature on gas separation. The results show that (1) the diffusion energy barrier and pore size are the primary factors in achieving the separation of water and methane. The diffusion energy barriers for the two molecules (CH4 and H2O) are ΔE(CH4) = 155.5 meV and ΔE(H2O) = 50.1 meV, respectively. (2) The ZIF-90 is more selective of H2O, which is mainly due to the strong interaction between the H2O molecule and the polar functional groups (such as aldehyde groups) within the ZIF-90. (3) A higher temperature accelerates the gas separation process. The higher the temperature is, the faster the separation process is. (4) The pore radius is identified as the intrinsic mechanism enabling the separation of water and methane in ZIF-90 membranes.

Investigation of dual inhibition of antibacterial and antiarthritic drug candidates using combined approach including molecular dynamics, docking and quantum chemical methods

Emerging antibiotic resistance in bacteria threatens immune efficacy and increases susceptibility to bone degradation and arthritic disorders. In our current study, we utilized a three-layer in-silico screening approach, employing quantum chemical methods, molecular docking, and molecular dynamic methods to explore the novel drug candidates similar in structure to floroquinolone (ciprofloxacin). We investigated the interaction of novel similar compounds of ciprofloxacin with both a bacterial protein S. aureus TyrRS (1JIJ) and a protein associated with gout arthritis Neutrophil collagenase (3DPE). UTIs and gout are interconnected through the elevation of uric acid levels. We aimed to identify compounds with dual functionality: antibacterial activity against UTIs and antirheumatic properties. Our screening based on several methods, sorted out six promising ligands. Four of these (L1, L2, L3, and L6) demonstrated favorable hydrogen bonding with both proteins and were selected for further analysis. These ligands showed binding affinities of −8.3 to −9.1 kcal/mol with both proteins, indicating strong interaction potential. Notably, L6 exhibited highest binding energies of −9.10 and −9.01 kcal/mol with S. aureus TyrRS and Neutrophil collagenase respectively. Additionally, the pkCSM online database conducted ADMET analysis on all lead ligand suggested that L6 might exhibit the highest intestinal absorption and justified total clearance rate. Moreover, L6 showed a best predicted inhibition constant with both proteins. The average RMSF values for all complex systems, namely L1, L2, L3 and L6 are 0.43 Å, 0.57 Å, 0.55 Å, and 0.51 Å, respectively where the ligand residues show maximum stability. The smaller energy gap of 3.85 eV between the HOMO and LUMO of the optimized molecule L1 and L6 suggests that these are biologically active compound. All the selected four drugs show considerable stabilization energy ranging from 44.78 to 103.87 kcal/mol, which means all four compounds are chemically and physically stable. Overall, this research opens exciting avenues for the development of new therapeutic agents with dual functionalities for antibacterial and antiarthritic drug designing.

An environmentally sustainable ultrasonic-assisted exfoliation approach to graphene and its nanocompositing with polyaniline for supercapacitor applications

In the present work, a green high-yielding method for the preparation of graphene is introduced via ultrasonic-assisted liquid phase exfoliation (LPE) of graphite in a green solvent medium, since the common preparation method of graphene via graphite oxide is hazardous. A high concentration of 3.2 mg/ml graphene is achieved here in a comparatively short duration of 3 h ultrasonication. By using a mixed solvents strategy (acetophenone and isopropyl alcohol, 1:19 V/V), surface energy requirements needed for the exfoliation of graphite are satisfied here with acetophenone, where isopropyl alcohol further facilitated the exfoliation via non-conventional CH-π and OH-π interactions. Turbostratic graphene in high-yield (16 %) in a simple means of ultrasonic assisted LPE is the added attraction of the present procedure. The less-defective structure of graphene, its few-layered turbostratic nature, and edge functionalization of the sheets are evident from the material characterization via Raman spectroscopy, XRD, TEM-SAED, and XPS analyses. Here, we report a combination of the attractive conducting polymer polyaniline (PANI) with the as-prepared graphene for supercapacitor applications, where the PANI/graphene nanocomposites with different aniline concentrations (PANI1.125/G, PANI4.5/G, and PANI9/G) have been prepared via in-situ polymerization of aniline in the graphene dispersion. The structure and morphology of the nanocomposites are investigated using different characterization techniques which revealed that the molecular structure of the PANI is retained in the nanocomposites even with a strong interaction with graphene. FESEM and TEM images revealed the good coverage of graphene sheets with PANI that limit the volume change of PANI during the repeated charge-discharge processes. Electrochemical studies showed that PANI4.5/G has the highest specific capacitance of 126.16 mF/cm2 at a current density of 1 mA/cm2, resulting from the perfect combination of the pseudocapacitance behavior of the PANI along with the electrical double layer capacitance of graphene. A symmetric supercapacitor device is also fabricated with PANI4.5/G, which showed the highest areal capacitance of 116.38 mF/cm2 similar to that with three-electrode studies and also good cycling stability with 87 % capacitance retention in the specific capacitance after 6000 cycles. It also exhibited an energy density of 16 µWh/cm2 (0.29 Wh/kg) and a power density of 3.99 mW/cm2 (72.72 W/kg).

Rational design of FeF2‐based cathode to realize high‐performance potassium storage

AbstractThe poor electronic conductivity of conversion‐type materials (CMs) and the dissolution/diffusion loss of transition metal (TM) ions in electrodes seriously hinder the practical applications of potassium ion batteries. Simply optimizing the electrode materials or designing the electrode components is no longer effective in improving the performance of CMs. Binders, as one of the electrode components, play a vital role in improving the electrochemical performance of batteries. Here we rationally designed FeF2 electrodes for the first time by optimizing electrode materials with the introduction of carbon nanotubes (CNTs) and combined with a sodium alginate (SA) binder based on strong interactions. We show that the FeF2@CNTs‐SA cathode does not suffer from TM ion dissolution and delivers a high capacity of 184.7 mAh g−1 at 10 mA g−1. Moreover, the capacity of FeF2@CNTs‐SA is as high as 99.2 mAh g−1 after 100 cycles at 100 mA g−1, which is a twofold increase compared to FeF2@CNTs‐PVDF. After calculating the average capacity decay rate per cycle of them, we find that FeF2@CNTs‐SA is about one‐third lower than FeF2@CNTs‐PVDF. Therefore, the SA binder can be broadly used for electrodes comprising several CMs, providing meaningful insights into mechanisms that lead to their improved electrochemical performances.

Carbon nanotube manipulates crystallization kinetics and viscoelastic behavior of PP/EBC blends

AbstractPolypropylene (PP) offers numerous benefits to industrial applications due to its excellent processability and cost‐effectiveness. However, the widespread utilization of this commodity thermoplastic is constrained by its inherently low‐impact resistance. Herein, we suggest a ternary system with the addition of ethylene‐butene copolymer (EBC) and multiwalled carbon nanotubes (MWCNTs) to improve the overall performance of PP. We unveil the role of MWCNTs on the crystalline behavior of the PP/EBC blends when various ratios are considered. The calculated half‐time crystallization from the Avrami equation indicates that 1.5 wt% MWCNTs accelerate the crystallization of the PP/EBC blend nearly threefold. The formation of a semisolid microstructure is also reported using the rheological measurements. An upturn in complex viscosity, along with a frequency‐independent storage modulus, indicates strong interactions between MWCNTs and polymer chains. We confirm such robust interactions by employing temperature ramp sweep on the prepared nanocomposites as the decomposition temperature of the materials shifts to higher values. The dynamic mechanical analysis further interprets the role of MWCNTs as compatibilizers by bridging the gap between the glassy temperature of PP and EBC components.Highlights Theoretical prediction of the MWCNTs localization in the PP/EBC blends. Depicting the solid‐like behavior and viscosity upturn of PP/EBC/MWCNTs. Decelerating polymer chain relaxation led by nucleation role of MWCNTs. Formation of larger and more imperfect crystals upon the addition of MWCNTs. Faster crystallization kinetics in the PP/EBC/MWCNTs nanocomposites.

Unveiling the Influence of Water Molecules on the Structural Dynamics of Prussian Blue Analogues.

3D-framework Prussian blue analogues (PBAs) are appealing as a cost-effective, sustainable cathodes for Na-ion batteries. However, the aqueous-based synthesis of PBAs inherently introduces three different forms of water molecules (surface, interstitial and crystal) into the structure. Removal of water molecules causes phase transformation from monoclinic (M) to rhombohedral (R). This work presents the effects of water molecules on the structure before the phase transformation temperature, employing two promising PBA cathodes, Na2Fe[Fe(CN)6]·1.69H2O and Na2Mn[Fe(CN)6]·1.76H2O. Specifically, the water molecules impact the molecular interactions at the local structure and the electrochemical properties. This work has performed calculations on low-vacancy Na2M[Fe(CN)6] PBAs (where M = Mn, Fe, Co, Ni and Cu) to understand the dehydration energy. Employing in situ high-temperature X-ray diffraction and Raman spectroscopy, this work observes that water removal induces negative thermal expansion and stronger interactions between C≡N and Na ions, resulting in biphasic reactions with sluggish kinetics. Additionally, water molecules play a role in maintaining the open 3D tunnels and facilitating a solid-solution like insertion of Na ions. Calculated phonon-Raman spectra provide insights into cyanide group deformations, revealing the interactions between water molecules, alkali-ions, and transition-metal ions. This study enhances the understanding of the relationship among electronic, vibrational, and electrochemical properties.

Multiferroic and Phonon Properties of the Double Perovskite Pr2FeAlO6.

With the help of a microscopic model and Green's function technique, we studied the multiferroic and phonon properties of the recently reported new multiferroic Pr2FeAlO6 (PFAO) compound, which belongs to the double perovskite A2BB'O6 family. The magnetization decreases with the increase in temperature and disappears at the ferromagnetic Curie temperature TCFM. The polarization increases with the application of an external magnetic field, indicating strong magnetoelectric coupling and confirming the multiferroic behavior of PFAO. In the curves of dependence of the phonon energy and their damping with respect to temperature, a kink is observed at TCFM. This is due to the strong anharmonic spin-phonon interactions, which play a crucial role below TCFM and are frequently observed in other double perovskite compounds. Above TCFM, only anharmonic phonon-phonon coupling remains. The phonon mode is controlled by an external magnetic field.

Synthesis and Characterization of New Copper(II) Coordination Compounds with Methylammonium Cations

We synthesized four new copper(II) complexes with acetato and chlorido ligands and methylammonium (MA), dimethylammonium (DMA), and tetramethylammonium (TMA) counterions: (MA)4[Cu2Ac4Cl2]Cl2·2H2O (1), (DMA)2[Cu2Ac4Cl2] (2), (DMA)4[Cu2Ac4Cl2]Cl2·2H2O (3), and (TMA)5[Cu2Ac4Cl]Cl4·4H2O (4). All compounds were characterized by single-crystal X-ray diffraction, magnetic measurements, FTIR spectroscopy, and thermogravimetric analysis. Complexes 1, 2, and 3 consist of a dinuclear coordination anion [Cu2(Ac)4Cl2]2− with bridging acetato ligands arranged in a paddle-wheel conformation and square-pyramidal coordination around Cu(II) atoms, while the coordination anion in compound 4 is a polymeric chain, parallel to the c axis, with Cu2(Ac)4 units connected through bridging chlorido ligands. Magnetic measurements carried out between 2 K and 300 K indicate strong antiferromagnetic interactions between Cu(II) ions. The effective magnetic moments range from 1.94 μB to 2.21 μB, exceeding the spin-only value for Cu(II) ions (μeff=1.73 μB) and suggesting significant orbital contributions to the magnetic moment. Thermogravimetric analysis of all complexes showed a multistep decomposition behavior yielding elemental copper as the final product.

Fabrication of a Heptapeptide-Modified Poly(glycidyl Methac-Rylate) Nanosphere for Oriented Antibody Immobilization and Immunoassay

Oriented antibody immobilization has been widely employed in immunoassays and immunodiagnoses due to its efficacy in identifying target antigens. Herein, a heptapeptide ligand, HWRGWVC (HC7), was coupled to poly(glycidyl methacrylate) (PGMA) nanospheres (PGMA-HC7). The antibody immobilization behavior and antigen recognition performance were investigated and compared with those on PGMA nanospheres by nonspecific adsorption and covalent coupling via carbodiimide chemistry. The antibodies tested included bovine, rabbit, and human immunoglobulin G (IgG), while the antigens included horseradish peroxidase (HRP) and β-2-Microglobulin (β2-MG). The nanospheres were characterized using zeta potential and particle size analyzers, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and reversed-phase chromatography, proving each synthesis step was succeeded. Isothermal titration calorimetry assay demonstrated the strong affinity interaction between IgG and PGMA-HC7. Notably, PGMA-HC7 achieved rapid and extremely high IgG adsorption capacity (~3 mg/mg) within 5 min via a specific recognition via HC7 without nonspecific interactions. Moreover, the activities of immobilized anti-HRP and anti-β2-MG antibodies obtained via affinity binding were 1.5-fold and 2-fold higher than those of their covalent coupling counterparts. Further, the oriented-immobilized anti-β2-MG antibody on PGMA-HC7 exhibited excellent performance in antigen recognition with a linear detection range of 0–5.3 μg/mL, proving its great potential in immunoassay applications.