Hydrogen-bonding Interactions Research Articles

Investigating the Inhibitory Potential of Flavonoids against Aldose Reductase: Insights from Molecular Docking, Dynamics Simulations, and gmx_MMPBSA Analysis.

Diabetes mellitus (DM) is a complex metabolic disorder characterized by chronic hyperglycemia, with aldose reductase playing a critical role in the pathophysiology of diabetic complications. This study aimed to investigate the efficacy of flavonoid compounds as potential aldose reductase inhibitors using a combination of molecular docking and molecular dynamics (MD) simulations. The three-dimensional structures of representative flavonoid compounds were obtained from PubChem, minimized, and docked against aldose reductase using Discovery Studio's CDocker module. The top 10 compounds Daidzein, Quercetin, Kaempferol, Butin, Genistein, Sterubin, Baicalein, Pulchellidin, Wogonin, and Biochanin_A were selected based on their lowest docking energy values for further analysis. Subsequent MD simulations over 100 ns revealed that Daidzein and Quercetin maintained the highest stability, forming multiple conventional hydrogen bonds and strong hydrophobic interactions, consistent with their favorable interaction energies and stable RMSD values. Comparative analysis of hydrogen bond interactions and RMSD profiles underscored the ligand stability. MMPBSA analysis further confirmed the significant binding affinities of Daidzein and Quercetin, highlighting their potential as aldose reductase inhibitors. This study highlights the potential of flavonoids as aldose reductase inhibitors, offering insights into their binding interactions and stability, which could contribute to developing novel therapeutics for DM complications.

Spatial Variations in Hydrogen Bonding Interaction within Polymer Blends Revealed by Infrared Nanoimaging.

Hydrogen bonding plays a crucial role in enhancing the miscibility of polymer blends, allowing for the tailoring of their physicochemical properties to meet diverse application demands. However, nanoscale imaging of its impact on the phase-separation behavior of multicomponent polymeric materials remains largely unexplored. In this work, we introduce scattering-type scanning near-field optical microscopy (s-SNOM) equipped with a broadly tunable quantum cascade laser as a tool for investigating spatial variations in hydrogen-bonding interactions within blends of polyvinyl acetate (PVAc) and polyvinylphenol (PVPh), spin-coated from tetrahydrofuran solution. Our multiwavelength s-SNOM imaging approach reveals distinct features, namely, the hydrogen bonding mediated miscible PVAc/PVPh blend and the phase-separated PVAc domain. These results provide a more detailed understanding, indicating that hydrogen bonding may not lead to a completely uniform blend throughout the film, as previously believed, based on far-field spectroscopy. Furthermore, through comparisons between topography and near-field images, we find that the PVAc/PVPh hydrogen-bonded domain exhibits a strong affinity for the Si surface with its native oxide, while the free (non-hydrogen-bonded) PVAc film is vertically phase-separated atop the blend. Overall, our work demonstrates that s-SNOM is an effective and efficient tool for studying intermolecular interactions relevant to various chemical and biological phenomena.

Chirality and Local Electron Density of States in a Two-Dimensional Molecular Crystal Self-Assembled by Prochiral Radical Molecules.

Creating and unveiling chiral systems is important to the development of new materials and devices. In this study, after depositing prochiral radical molecule 3-carbamoyl-2,2,5,5-tetramethyl pyrroline-1-oxyl (CTPO) on a Au(111) substrate, 2D molecular crystals with two chiralities of CTPO molecules have been discovered. A single CTPO molecule is an achiral molecule in three-dimensional space, and it can form chiral configurations after adsorbing on the substrate. The chiralities of 2D molecular crystals originate from the chiral properties of adsorbed CTPO molecules and their assembling. Molecules with different chiralities are connected with molecular recognition through hydrogen bond interactions. Through density functional theory simulations, the hydrogen bond networks and molecular structures of this system were explored. To gain a further understanding of this system, the electronic property of CTPO/Au(111) was studied with a local density of states (LDOS) characterization. A peculiar LDOS distribution related to the vibrational excitation of the molecules was mapped at the submolecular scale. These results are useful for understanding the nature of chirality formation, 2D molecular crystal construction, and radical molecule applications.

Sieving‐type Electric Double Layer with Hydrogen Bond Interlocking to Stable Zinc Metal Anode

AbstractThe stability of aqueous zinc metal batteries is significantly affected by side reactions and dendrite growth on the anode interface, which primarily originate from water and anions. Herein, we introduce a multi H‐bond site additive, 2, 2′‐Sulfonyldiethanol (SDE), into an aqueous electrolyte to construct a sieving‐type electric double layer (EDL) by hydrogen bond interlock in order to address these issues. On the one hand, SDE replaces H2O and SO42− anions that are adsorbed on the zinc anode surface, expelling H2O/SO42− from the EDL and thereby reducing the content of H2O/SO42− at the interface. On the other hand, when Zn2+ are de‐solvated at the interface during the plating, the strong hydrogen bond interaction between SDE and H2O/SO42− can trap H2O/SO42− from the EDL, further decreasing their content at the interface. This effectively sieves them out of the zinc anode interface and inhibits the side reactions. Moreover, the unique characteristics of trapped SO42− anions can restrict their diffusion, thereby enhancing the transference number of Zn2+ and promoting dendrite‐free deposition and growth of Zn. Consequently, utilizing an SDE/ZnSO4 electrolyte enables excellent cycling stability in Zn//Zn symmetrical cells and Zn//MnO2 full cells with lifespans exceeding 3500 h and 2500 cycles respectively.

Chemical enhanced oil recovery using carbonized ZIF-67 MOFs and sulfonated copolymers at high reservoir temperatures

Traditional nanoparticle and polymer-based enhanced oil recovery methods face challenges such as nanoparticle agglomeration and polymer adsorption, particularly at elevated reservoir temperatures. This study introduces hybrid polymeric nanofluids, combining carbonized Zeolitic Imidazolate Framework-67 (ZIF-67) with sulfonated copolymers to address these issues. Viscosity tests were conducted at 25 °C, 50 °C, 75 °C, and 90 °C, revealing a 39.67 % increase in viscosity at 90 °C, attributed to electrostatic and hydrogen bond interactions. For subsequent analyses—stability, adsorption, and core flooding—75 °C was selected as the representative high reservoir temperature. Stability assessments, confirmed via UV–Vis spectroscopy, demonstrated nanofluid durability over at least seven days. Carbonized ZIF-67 reduced polymer adsorption on rock surfaces, enhancing oil recovery and reducing environmental impact. Dynamic core flooding experiments showed a 45.8 % improvement in oil recovery by the hybrid nanofluid on carbonate rock samples. The hybrid nanofluid increased RF and RRF, improving the mobility ratio and redirecting flow to lower-permeability zones, reducing unswept oil and enhancing macroscopic sweep efficiency. Winsor Type III emulsification during the post-flooding phase of polymer-nanoparticle injection significantly improved trapped oil mobilization. Reduced contact angles from 170° to 100° altered the wettability, enhancing oil recovery. Carbonized ZIF-67 nanoparticles increased viscous forces, reduced capillary forces, and minimized polymer adsorption. The polymeric nanofluid achieved a capillary number of 1.0 × 10−3, two orders higher than that of polymer alone, resulting in superior performance. Injectivity optimization showed shear rates of 15.9 s−1 in 1700 mD cores and 79.8 s−1 in 80 mD cores, causing pressure drops of 15 psi and 1200 psi, respectively. This highlights injectivity challenges in 80 mD cores, while cores ≥ 290 mD are ideal for our polymer-nanoparticle hybrid applications.

Combinatory Effect of Gemcitabine and 5‐Fluorouracil Investigated Through Chemoinformatics and Molecular Dynamics Simulation Against Breast Cancer

ABSTRACTCo‐delivering FDA‐approved drugs can be less harmful and boost biological activity by targeting different protein mechanism at same time. Gemcitabine and 5‐Fluorouracil (GE5F) adduct work together to destroy cancer cells and increase the efficacy in the fight against breast cancer. The basis set B3LYP/6‐311 G was utilized in this investigation to improve the structure of GE5F adduct. The natural bond analysis exhibited the intermolecular interactions of the GE5F adduct. Electronic transitions were seen to be π → π*, and theoretical calculations were performed for the ultraviolet to visible spectrum. The energy gap between HOMO and LUMO was used to study the GE5F adduct's structural stability and reactivity; the computed energy gap (ΔE) was 3.912 eV. The Mulliken charge population was assessed and the complex structure's electrostatic potential was established. Weak interactions of the GE5F were assessed using RDG analysis, and topological aspects were investigated using LOL and ELF analysis. Investigating the GE5F adduct's adsorption, distribution, metabolism, excretion, and toxicity properties, the results confirmed that GE5F adduct comes under the safety parameters being a drug‐likeness molecule. Molecular docking experiments were conducted using target proteins for breast cancer. The complex molecule had a higher binding affinity as indicated by the docking scores, which validated the better combinatorial interaction between gemcitabine and 5‐Fluorouracil. With − 9.4 kcal/mol, the complex molecule's strongest binding capacity was against PARP protein, and stable confirmation was observed through molecular dynamic simulation for 100 ns with four hydrogen bond interactions. These in silico finding will pave a way for in vitro and in vivo experiments with better enhancement of FDA approved drugs.

Manganese nanoparticles catalyzed the formation of mesoporous helical nitrogen-doped carbon nanotubes enabled aldosterone biosensing

Primary aldosteronism (PA) is the foremost form of secondary hypertension that affects 5–20 % of healthy humans via the excessive secretion of aldosterone (ALD), which increases the level of potassium excretion and thus produces various critical combined diseases. Thus, determining trace-level ALD content in human blood or urine samples is a crucial factor in diagnosing a life-threatening disease called PA. Herein, nanosized manganese particles encapsulated within the tunable helical-shaped N-doped mesoporous carbon nanotubes (Mnx@H-NCNTs) are synthesized by a simple and facile ball-milling method at different reaction times (1, 6, 12, and 18 h). The influence of ball-milling process time on the final morphology of the as-synthesized Mnx@H-NCNTs nanostructures is systematically investigated. In order to fabricate an ALD biosensor electrode, the immobilization of Anti-ALD antibodies (Anti-ALD) on the surface of the Mn@H-NCNTs-12H electrode (Anti-ALD/Mn@H-NCNTs-12H) is achieved via the interactions of combined interactions of hydrogen bonds, Van der Waals’ force, negatively charged carboxylic acid functionalities of antibodies and positively charged metal centers, and π-π stacking interaction between nucleosides of Anti-ALD and mesoporous H-NCNTs. In addition, BSA was used as a blocking additive for covering non-specific adsorption sites of Anti-ALD/Mnx@H-NCNTs (BSA/Anti-ALD/Mn@H-NCNTs-12H) nanostructured electrodes. The BSA/Anti-ALD/Mn@H-NCNTs-12H can be used as an effective signal amplifying probe for ALD detection through a noticeable reduction in the amperometric i-t current response over a linear range from 1 to 2500 pM, with a LOD of 0.72 pM (S/N = 3). The practical applicability of BSA/Anti-ALD/Mn@H-NCNTs-12H is further demonstrated by the detection of ALD from 1 to 20 nM in human blood or urine samples with a recovery ranging from 90.5 to 97.0 %, indicating its potential use in clinical analysis.

Exploring the Origins of Low-Temperature Thermochromism in Polydiacetylenes.

This review article delves into the intriguing phenomenon of low-temperature thermochromism, whereby materials change color in response to temperature variations, with a particular focus on its applications in temperature-sensitive fields like medical storage. By closely examining thermochromic materials, this article highlights their potential to offer innovative solutions for monitoring and preserving thermolabile products that require strict temperature control. This leads to a special emphasis on polydiacetylenes (PDAs), a class of conjugated polymers with unique low-temperature thermochromic properties, positioning them as promising candidates for reliable temperature indicators. This article then explores the underlying mechanisms for fine-tuning the thermochromic behavior of PDAs, particularly discussing recent advancements in PDA design, such as structural alterations of monomers to achieve low-temperature thermochromism. These modifications, influenced by factors like side-chain length, hydrogen-bonding interactions, and the use of copolymers, are intended to result in irreversible color transitions at specific low temperatures, which is crucial to maintaining the integrity of thermally sensitive products. Finally, this article discusses the potential applications of PDAs as thermochromic sensors in tissue biobanking, where their ability to provide visual indications of temperature fluctuations could significantly enhance the monitoring and management of biological samples.

Ursolic acid interaction with transcription factors BRAF, V600E, and V600K: a computational approach towards new potential melanoma treatments.

Melanoma is one of the cancers with the highest mortality rate for its ability to metastasize. Several targets have undergone investigation for the development of drugs against this pathology. One of the main targets is the kinase BRAF (RAF, rapidly accelerated fibrosarcoma). The most common mutation in melanoma is BRAFV600E and has been reported in 50-90% of patients with melanoma. Due to the relevance of the BRAFV600E mutation, inhibitors to this kinase have been developed, vemurafenib-OMe and dabrafenib. Ursolic acid (UA) is a pentacyclic triterpene with a privileged structure, the pentacycle scaffold, which allows to have a broad variety of biological activity; the most studied is its anticancer capacity. In this work, we reported the interaction profile of vemurafenib-OMe, dabrafenib, and UA, to define whether UA has binding capacity to BRAFWT, BRAFV600E, and BRAFV600K. Homology modeling of BRAFWT, V600E, and V600K; molecular docking; and molecular dynamics simulations were carried out and interactions and residues relevant to the binding of the inhibitors were obtained. We found that UA, like the inhibitors, presents hydrogen bond interactions, and hydrophobic interactions of van der Waals, and π-stacking with I463, Q530, C532, and F583. The ΔG of ursolic acid in complex with BRAFV600K (- 63.31kcal/mol) is comparable to the ΔG of the selective inhibitor dabrafenib (- 63.32kcal/mol) in complex to BRAFV600K and presents a ΔG like vemurafenib-OMe with BRAFWT and V600E. With this information, ursolic acid could be considered as a lead compound for design cycles and to optimize the binding profile and the selectivity towards mutations for the development of new selective inhibitors for BRAFV600E and V600K to new potential melanoma treatments. The homology modeling calculations were executed on the public servers I-TASSER and ROBETTA, followed by molecular docking calculations using AutoGrid 4.2.6, AutoDockGPU 1.5.3, and AutoDockTools 1.5.6. Molecular dynamics and metadynamics simulations were performed in the Desmond module of the academic version of the Schrödinger-Maestro 2020-4 program, utilizing the OPLS-2005 force field. Ligand-protein interactions were evaluated using Schrödinger-Maestro program, LigPlot + , and PLIP (protein-ligand interaction profiler). Finally, all of the protein figures presented in this article were made in the PyMOL program.

Adipogenic Effects of Cresyl Diphenyl Phosphate (Triphenyl Phosphate Alternative) through Peroxisome Proliferator-Activated Receptor Gamma Pathway: A Comprehensive Study Integrating In Vitro, In Vivo, and In Silico from Molecule to Health Risk.

Cresyl diphenyl phosphate (CDP), a novel organophosphate ester (OPE), has been detected in various environmental and human samples. However, there is very limited knowledge regarding its toxicity, mechanisms of action, and potential health risks. Using new alternative methods (NAMs), across the molecular interactions, signaling pathways, cell functions, animal effects, and population risks, we investigated the potential adipogenic effects and associated risks of CDP and legacy OPE triphenyl phosphate (TPHP) by acting on peroxisome proliferator-activated receptor gamma (PPARγ). Among the 19 screened OPEs, CDP bound to PPARγ with the highest binding potency, followed by TPHP. CDP activated PPARγ through fitting into the binding pocket with strong hydrophobicity and hydrogen bond interactions; CDP exhibited higher potency compared to TPHP. In 3T3-L1 cells, CDP enhanced the PPARγ-mediated adipogenesis activity, exhibiting greater potency than TPHP. The intracellular concentration and receptor-bound concentrations (RBC) of CDP were also higher than those of TPHP in both HEK293 cells and 3T3-L1 cells. In mice, exposure to CDP activated the PPARγ-mediated adipogenic pathway, leading to an increased white adipose tissue weight gain. Overall, CDP could bind to and activate PPARγ, thereby promoting preadipocyte differentiation and the development of white adipose tissue. Its potential obesogenic risks should be of high concern.

DYNAMICS IN ELASTOMERS WITH HYDROGEN BOND INTERACTIONS

ABSTRACT The dynamics of low molecular weight polybutadiene (PB) functionalized with side chains able to form hydrogen-bonded networks is investigated by a combination of calorimetry, rheology, and broadband dielectric spectroscopy (BDS). The modified PBs are found to have extremely different macroscopic viscosities with respect to the starting polymer; however, rather unexpectedly, when investigated using these three techniques, we find that the changes to the segmental motion responsible for the glass transition temperature remain unchanged. This is attributed to the high flexibility of the side chain, which does not restrict the motions of the highly flexible segments in the PB chain. In the presence of the hydrogen-bonded network we observe in both the rheological and dielectric spectra an additional relaxation, orders of magnitude slower than the segmental relaxation. We find that the temperature dependence and its dynamics are well explained in terms of the lifetime of the hydrogen bond, with a binding energy of about 100 kJ/mol.

Rotameric heterogeneity of conserved tryptophan is responsible for reduced photochemical quantum yield in cyanobacteriochrome slr1393g3.

The red/green cyanobacteriochrome (CBCR) slr1393g3 exhibits a quantum yield of only 8% for its forward photoconversion significantly lower than other species from the same CBCR subfamily. The cause for this reduced photoconversion is not yet clear, although in the related NpR6012g4 dark-state structural heterogeneity of a paramount Trp residue has been proposed to cause the formation of nonproductive subpopulation. However, there is no such information on the equivalent residue in slr1393g3, W496. Here we use solid-state NMR to explore all possible sidechain rotamers of this Trp residue and their local interactions at the atomic level. The indole nitrogen (Nε1) is used as an NMR probe, achieved by site-specific 15N-indole labeling of a quadruply Trp-deleted variant and trehalose vitrification technique. The data reveal a set of seven indole rotamers of W496 with four distinct environments for the Nε1-H group. Only a minority population of 20% is found to retain the π-stacking and hydrogen-bonding interactions with the chromophore in the dark state that has been assigned to account for complete forward photoconversion. Our results demonstrate the direct role of W496 in modulating the forward quantum yield of slr1393g3 via rearrangement of its sidechain rotameric conformations.

Tunable Coassembly of Octaarginine with Thiazolyl Benzenesulfonamides Exerts Variable Antibacterial Activity.

The cationic peptide octaarginine (R8) is a prominent cell-penetrating peptide and has been extensively researched as a carrier of diverse cell-destined cargo. In this work, we describe the coassembly of R8 with small molecule thiazolyl benzenesulfonamide (TBS) derivatives. Physical complexation of R8 with three TBS derivatives across a range of weight ratios results in the formation of a distinctive set of nano- and microstructures. A detailed structural characterization of the R8:TBS-derivative coassemblies has been performed by a combination of FTIR, XRD, SEM, and DSC. The major functional groups that facilitate coassembly include sulfonamide SO2 and NH groups of the TBS derivatives, and the guanidinium of R8, via a combination of cation-π and hydrogen-bonding interactions. The R8:4F-TBS coassembly displays singular topological features compared to R8:4Br-TBS and R8:4CH3-TBS complexes. These differences are attributed to the changes in the preferred orientation of the guanidino groups of R8 with respect to the π-surface of TBS derivatives. The modulation of forces of interaction across the R8:TBS-derivative coassemblies aligns with their respective thermal stabilities. The single-crystal structure of bare 4F-TBS has been subjected to Hirshfeld and 2D fingerprinting analysis and indicates notable variations from the crystal packing of the R8:4F-TBS coassembly. The structural differences among the R8:TBS-derivative coassemblies correlate with distinctive profiles of antibacterial activity in each case. The coassembled structures exert a variable extent of bacterial membrane disruption and damage based on the unique disposition of R8 and the potency of small molecule in each case. The aqueous suspension of R8:4F-TBS displays significant outer membrane disruption and bacterial killing compared with the other complexes. This work successfully demonstrates the hitherto unreported potential for coassembly of cell-penetrating peptides with other entities. The coassembly of R8 with small molecules highlights an attractive strategy for tuning the functional properties of each component.

Improvement of okara noodle quality by modifying the soluble/insoluble dietary fibre ratio

This study investigated the effect of okara modified through cellulase hydrolysis and extrusion on noodle quality. Modification increased the soluble dietary fibre/insoluble dietary fibre (SDF/IDF) ratio in okara, improved appearance, cooking, and texture, and reduced starch digestibility of okara noodles. The 4.0 % cellulase enzymolysis-extruded okara noodles exhibited the quality closest to that of wheat noodles, with an estimated glycaemic index (eGI) < 55 (low-GI). As the okara SDF/IDF ratio increased, the water mobility of noodles decreased, indicating that an increase in the SDF/IDF ratio reduced competitive water absorption of okara. In addition, increased SDF/IDF ratio increased β-sheet content and promoted the enhanced hydrogen bond interactions between proteins and polymerisation between gliadin and glutenin. Moreover, the microstructure of noodles with a higher SDF/IDF ratio of okara was more continuous and compact, further confirming the promotional effect of okara with a higher SDF/IDF ratio on the quality of okara noodles.

Enhanced mechanical and dielectric properties of lignocellulosic composite papers with biomimetic multilayered structure and multiple hydrogen-bonding interactions

Lignocellulosic papers (LCP) are favored for electrical insulating applications due to their environmental friendliness, ease of processing, and cost-effectiveness. However, the loose structure and numerous pores inside LCP result in the poor mechanical and electrical insulating properties, posing challenges in meeting the requirements for the rapid upgrading of high-voltage electrical equipment. Herein, a 3D interconnective structure composed of 3D aramid nanofibers (ANF) and 2D carbonylated basalt nanosheets (CBSNs) is introduced to enhance the structure and the chemical bonding interactions of LCP. This is achieved by impregnating LCP into an ANF-CBSNs suspension, where the 3D interconnective ANF framework hosts numerous CBSNs. The resultant LCP/ANF-CBSNs (LCP/A-C) composite papers exhibit multilayered structure and multiple hydrogen-bonding interactions, demonstrating excellent mechanical and electrical insulating properties. Notably, the optimized LCP/A-C5 composite papers exhibit remarkable tensile strength (23.15 MPa) and dielectric breakdown strength (20.14 kV·mm−1), respectively, representing 229 % and 145 % increase compared to those of the control LCP. These impressive properties are integrated with excellent bending ability, outstanding high temperature resistance, exceptional volume resistivity, and low dielectric constant and loss, demonstrating their potential as highly promising electrical insulating papers for advanced high-power electrical equipment.

Crystal structure of a hydrogen-bonded 2:1 co-crystal of 4-nitrophenol and 4,4′-bipyridine

In the title compound, C10H8N2·2C6H5NO3, 4-nitrophenol and 4,4′-bipyridine crystallized together in a 2:1 ratio in the space group P21/n. There is a hydrogen-bonding interaction between the nitrogen atoms on the 4,4′-bipyridine molecule and the hydrogen atom on the hydroxyl group on the 4-nitrophenol, resulting in trimolecular units. This structure is a polymorph of a previously reported structure [Nayak &amp; Pedireddi (2016). Cryst. Growth Des. 16, 5966–5975], which differs mainly due to a twist in the 4,4′-bipyridine molecule.

Mercury(II) halide complex of cis-[( t BuNH)(Se)P(μ-N t Bu)2P(Se)(NH t Bu)

The mercury(II) halide complex [1,3-di-tert-butyl-2,4-bis(tert-butylamino)-1,3,2λ5,4λ5-diazadiphosphetidine-2,4-diselone-κ2 Se,Se′]diiodidomercury(II) N,N-dimethylformamide monosolvate, [HgI2(C16H38N4P2Se2)]·C3H7NO or (1)HgI2, 2, containing cis-[( t BuNH)(Se)P(μ-N t Bu)2P(Se)(NH t Bu)] (1) was synthesized and structurally characterized. The crystal structure of 2 confirms the chelation of chalcogen donors to HgI2 with a natural bite angle of 112.95 (2)°. The coordination geometry around mercury is distorted tetrahedral as indicated by the τ4 geometry index parameter (τ4 = 0.90). In the mercury complex, the exocyclic tert-butylamido substituents are arranged in an (endo, endo) fashion, whereas in the free ligand (1), the exocyclic substituents are arranged in an (exo, endo) pattern. Compound 2 displays non-classical N—H...O hydrogen-bonding interactions with the solvent N,N-dimethylformamide. These interactions may introduce geometrical distortion and deviation from an ideal geometry. An isostructural HgBr2 analogue containing cis-[( t BuNH)(S)P(μ-N t Bu)2P(S)(NH t Bu)] was also synthesized and structurally characterized, CIF data for the compound being presented as supporting information.

Polymeric Manganese(II) Acetate Derivatives: Syntheses, Crystal Structures and Magnetic Properties

AbstractThree novel polymeric Mn(II) acetate derivatives, identified as {[Mn2.5(OH)(CH3COO)4] ⋅ 0.5CH3OH ⋅ 0.5CH3CN}n (1), {[Mn3(CH3CO O)6] ⋅ 0.5CH3CN}n (2) and {Mn1.5K(CH3COO)4}n (3), have been successfully prepared by systematically adjusting the ratio of reactants and using the 2‐mercapto‐5‐methyl‐1,3,4‐thiadiazole (Hmmt) as the template agent. These three complexes can be regarded as the different crystalline forms of Mn(CH3COO)2 under different reaction conditions. Single‐crystal X‐ray diffraction analyses revealed that 1 and 2 feature the unique three‐dimensional (3D) framework. For 3, it displays a 2D structure, which is further assembled to form a 3D extended network via the weak hydrogen bond interactions. Magnetic studies confirmed that 1 and 2 show antiferromagnetic interactions, and 1 displays a long‐range ordering phase below the critical temperature (Tc) of 7.8 K. In addition, magnetisation data collected for 1–2 yield low magnetic entropy changes, which can be attributed to the strong antiferromagnetic interactions among the Mn(II) centres.

Electroanalytical detection of fruit ethylene by a novel electroactive biosensing membrane

Purpose This study aims to present an innovative approach to detect and monitor ethylene gas during fruit ripening. Design/methodology/approach It uses a specialized composite membrane in conjunction with a solid-state electrochemical method. This unique electroactive membrane, composed of polyvinyl alcohol (PVA), chitosan (CHT), lithium chloride (LiCl) and ammonium molybdate (AMO), exhibits synergistic behavior when applied to a microelectrode chip surface. This composite enhances the sensitivity of electrochemical ethylene detection. Empirical experiments were conducted to elucidate the ripening kinetics in various fruit specimens, including apples, pears and mangoes. These fruits released ethylene, which was analyzed using the molybdenum-permeated electroactive biopolymer composite membrane, a critical determinant of ethylene levels. Findings Characterization of the synthesized composite through techniques such as X-ray diffraction and Fourier-transform infrared spectroscopy revealed reduced crystallinity and decreased hydrogen bond interactions upon activation with Mo ions. Field emission scanning electron microscopy images exhibited a distinctive porous surface morphology with spherical microgranules. Energy dispersive X-ray analysis indicated a significant change in the mass or atomic composition of Mo in the composite membrane after Mo ion activation. Electrochemical measurements, including cyclic voltammetry and potentiostatic electrochemical impedance spectroscopy, validated the efficiency of the Mo-activated PVA-CHT-LiCl-AMO membrane, manifesting an impressive 87.79% increase in sensitivity compared to the nonactivated membrane. Practical implications This research work represents a significant advancement in the field of ethylene detection and fruit ripening monitoring. The Mo-activated PVA-CHT-LiCl-AMO membrane offers a reliable and effective solution for real-time ethylene detection, providing an invaluable tool for the horticultural industry to optimize fruit ripening processes, extend shelf life and ensure the delivery of high-quality produce to consumers. Social implications The findings of this study hold great promise for fostering sustainability and efficiency within the global fruit supply chain, ultimately benefiting both producers and consumers alike. Originality/value The implications of this research extend to the fabrication of a sensor based on a solid-state electroactive PVA-CHT-LiCl-AMO composite membrane, which upon Mo-activation exhibits robust electrochemical fruit ethylene detection when exposed to different fruits.

Computational exploration of acefylline derivatives as MAO-B inhibitors for Parkinson's disease: insights from molecular docking, DFT, ADMET, and molecular dynamics approaches.

Monoamine oxidase B (MAO-B) plays a pivotal role in the deamination process of monoamines, encompassing crucial neurotransmitters like dopamine and norepinephrine. The heightened interest in MAO-B inhibitors emerged after the revelation that this enzyme could potentially catalyze the formation of neurotoxic compounds from endogenous and exogenous sources. Computational screening methodologies serve as valuable tools in the quest for novel inhibitors, enhancing the efficiency of this pursuit. In this study, 43 acefylline derivatives were docked against the MAO-B enzyme for their chemotherapeutic potential and binding affinities that yielded GOLD fitness scores ranging from 33.21 to 75.22. Among them, five acefylline derivatives, namely, MAO-B14, MAO-B15, MAO-B16, MAO-B20, and MAO-B21, displayed binding affinities comparable to the both standards istradefylline and safinamide. These derivatives exhibited hydrogen-bonding interactions with key amino acids Phe167 and Ile197/198, suggesting their strong potential as MAO-B inhibitors. Finally, molecular dynamics (MD) simulations were conducted to evaluate the stability of the examined acefylline derivatives over time. The simulations demonstrated that among the examined acefylline derivatives and standards, MAO-B21 stands out as the most stable candidate. Density functional theory (DFT) studies were also performed to optimize the geometries of the ligands, and molecular docking was conducted to predict the orientations of the ligands within the binding cavity of the protein and evaluate their molecular interactions. These results were also validated by simulation-based binding free energies via the molecular mechanics energies combined with generalized Born and surface area solvation (MM-GBSA) method. However, it is necessary to conduct in vitro and in vivo experiments to confirm and validate these findings in future studies.