Water Molecules Research Articles

Enhancing Carrier Behavior via Controlled Molecular Film Formation Engineering Leads to Significant Improvement in Electroluminescence

The quality of organic thin films critically influences carrier dynamics in organic semiconductors. In neat/doped films, even tiny voids can be penetrated by water or oxygen molecules to create charge‐trap states called water/oxygen‐induced traps that significantly hinder carrier mobility. While the water/oxygen‐induced traps in non‐doped films and crystalline states have been investigated comprehensively, there is a lack of thorough examination regarding their properties in the doped state. Therefore, there is a high demand for a molecular design strategy that effectively modulates the molecular stacking behavior in doped films and practical devices and enhances the quality of these films. Herein, we proposed a versatile molecular design principle that enables the formation of "nano‐cluster" structures on both the surface and interior of doped films in target molecule 10‐(4‐(4,6‐diphenyl‐1,3,5‐triazin‐2‐yl)phenyl)‐1'‐(4‐fluorophenyl)‐10H‐spiro[acridine‐9,9'‐xanthene] (DspiroO‐F‐TRZ), which is modified with a fluorophenyl group. These "nano‐cluster" structures exhibit more uniform shapes within doped films and effectively reduce defective state densities while enhancing carrier injection and transport properties, ultimately improving device performance. Notably, TADF‐OLED based on DspiroO‐F‐TRZ demonstrates nearly twice as much efficiency as its control counterpart due to contributions from 'nano‐cluster' structure enhancements toward improved electroluminescence performance.

Enhancing Carrier Behavior via Controlled Molecular Film Formation Engineering Leads to Significant Improvement in Electroluminescence.

The quality of organic thin films critically influences carrier dynamics in organic semiconductors. In neat/doped films, even tiny voids can be penetrated by water or oxygen molecules to create charge-trap states called water/oxygen-induced traps that significantly hinder carrier mobility. While the water/oxygen-induced traps in non-doped films and crystalline states have been investigated comprehensively, there is a lack of thorough examination regarding their properties in the doped state. Therefore, there is a high demand for a molecular design strategy that effectively modulates the molecular stacking behavior in doped films and practical devices and enhances the quality of these films. Herein, we proposed a versatile molecular design principle that enables the formation of "nano-cluster" structures on both the surface and interior of doped films in target molecule 10-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-1'-(4-fluorophenyl)-10H-spiro[acridine-9,9'-xanthene] (DspiroO-F-TRZ), which is modified with a fluorophenyl group. These "nano-cluster" structures exhibit more uniform shapes within doped films and effectively reduce defective state densities while enhancing carrier injection and transport properties, ultimately improving device performance. Notably, TADF-OLED based on DspiroO-F-TRZ demonstrates nearly twice as much efficiency as its control counterpart due to contributions from 'nano-cluster' structure enhancements toward improved electroluminescence performance.

Theoretical Study of the Effects of Different Coordination Atoms (O/S/N) on Crystal Structure, Stability, and Protein/DNA Binding of Ni(II) Complexes with Pyridoxal-Semi, Thiosemi, and Isothiosemicarbazone Ligand Systems

Nickel transition metal complexes have shown various biological activities that depend on the ligands and geometry. In this contribution, six Ni(II) nitrate complexes with pyridoxal-semi, thiosemi, and isothiosemicarbazone ligands were examined using theoretical chemistry methods. The structures of three previously reported complexes ([Ni(PLSC)(H2O)3]∙2NO3−, [Ni(PLTSC)2] ∙2NO3−∙H2O, and [Ni(PLITSC)(H2O)3]∙2NO3−) were investigated based on Hirshfeld surface analysis, and the most important stabilization interactions in the crystal structures were outlined. These structures were optimized at the B3LYP/6-311++G(d,p)(H,C,N,O,(S))/LanL2DZ(Ni) level of theory, and the applicability was checked by comparing theoretical and experimental bond lengths and angles. The same level of theory was applied for the optimization of three additional structures, ([Ni(PLSC)2]2+, [Ni(PLTSC)(H2O)3]2+, and [Ni(PLITSC)2]2+). The interactions between selected ligands and Ni(II) were examined using the Natural Bond Orbital (NBO) and Quantum Theory of Atoms in Molecules (QTAIM) approaches. Particular emphasis was placed on interactions between oxygen, sulfur, and nitrogen donor atoms and Ni(II). Human Serum Albumin (HSA) and the DNA-binding properties of these complex cations were assessed using molecular docking simulations. The presence of water molecules and various substituents in the thermodynamics of the processes was demonstrated. The results showed significant effects of structural parameters on the stability and reactivity towards important biomolecules.

Direct ink writing of customized polymeric structures embedded in a nano-silicate based supporting matrix

The increase in use of intricate structures for engineering applications has encouraged researchers to find new fabrication techniques. This work presents an innovative approach of embedded 3D printing, which allows fabrication of freeform structures by directly 3D printing inside a supporting matrix. The polymer ink solution was prepared by blending polylactic acid (PLA) and polypropylene carbonate (PPC) in 1,4-dioxane. Laponite RD was used to prepare the aqueous nano-silicate suspension, which exhibited yield stress and thixotropic properties due to its house-of-cards arrangement. Solidification of the 3D printed polymer ink occurred due to the hydrogen bonding between the oxygen atoms of dioxane molecules and the protons of water molecules. Particle image velocimetry study showed that the increasing nano-silicate concentration caused a reduction in yield region as a result of increasing yield stress. Dimensionless parameters (Oldroyd number and ratio of yield stress to hydrostatic pressure) for nano-silicate concentrations with values less than 1 were found to facilitate the nozzle movement without crevice formation, while the values greater than 1 were found to be unsuitable for printing. Different intricate structures such as tubular structures with varying geometry that mimic the native trachea, and a bifurcated tube were 3D printed as a proof-of-concept study. The proposed method introduced a novel approach by utilizing the solvent-water interaction capability to fabricate objects with overhanging geometry. This approach allows 3D printing of a wide variety of polymers by leveraging the miscibility between its corresponding solvent and supporting matrix.

Proton Conduction via Water and Ammonia Coordinated Metal Cationic Species in MOF and MHOF Platforms.

Although metal-organic frameworks (MOFs) and metalo hydrogen-bonded organic frameworks (MHOFs) are designed as promising solid-state proton conductors by incorporating various protonic species intrinsically or extrinsically, design and development of such materials by employing the concept of proton conduction through coordinated polar protic solvent is largely unexplored. Herein, we have constructed two proton-conducting materials having different solvent coordinated metal cationic species: In-H2O-MOF, ({[In(H2O)6][In3(Pzdc)6]·15H2O}n; H2Pzdc: pyrazine-2,3-dicarboxylic acid) with coordinated water molecules from hexaaquaindium cationic species, and MHOF-4, ([{Co(NH3)6}2(2,6-NDS)2(H2O)2]n; 2,6-H2NDS: 2,6-naphthalenedisulfonic acid) with coordinated ammonia from hexaammoniacobalt cationic species. Interestingly, higher proton conductivity was achieved for In-H2O-MOF (1.5 × 10-5 S cm-1) than MHOF-4 (6.3 × 10-6 S cm-1) under the extreme conditions (80 ºC and 95% RH), which could be attributed to enhanced acidity of coordinated water molecules having much lower pKa value than that of coordinated ammonia. Greater charge polarization on hydrogen atoms of In3+-coordinated water molecules than that of Co2+-coordinated ammonia led to the high conductivity of In-H2O-MOF, as evident by quantum chemical studies. Such a comparative study on metal-coordinated protic polar solvents in achieving proton conduction in crystalline solids is yet to be made.

Role of Nitrogen-doping in porous carbon for enlarging working voltage window of aqueous supercapacitors in neutral electrolyte

The fundamental mechanism on enlarging working voltage window of carbon-based aqueous supercapacitors is still unclear owing to the indistinct principles in inhibiting water splitting occurred at the electrochemical interface. Herein, we design a set of N, O co-doped porous carbon (NOPC) free-standing electrodes with adjustable N-doping level, and establish that N-doping (N-content and specific N-configuration) governs neutral HER and OER. The NOPC electrode with a lower N-doping level can possess a wide working potential window of − 1–1 V, and thus the corresponding aqueous symmetric supercapacitors showcase a wide working voltage window of 2 V in LiCl aqueous solution. In situ spectroscopy evidences and theoretical simulation demonstrate that the low N-doping (N-content and percentage of pyrrolic nitrogen) level can weaken the interaction between the electrode and interfacial water molecules and suppress the formation of *OOH intermediate during the charge–discharge process, and thus significantly decreasing the HER and OER activities to inhibit water splitting. The finding can shed light on the fundamental understanding of mechanism on enlarging working voltage window of carbon-based aqueous supercapacitor.

Synthesis, crystal structure, spectroscopic, electronic and vibrational properties of N′-[(E)-3-pyridinylmethylene]nicotinohydrazide trihydrate: Experimental and computational study

N′-[(E)-3-pyridinylmethylene]nicotinohydrazide trihydrate (C12H10N4O·3(H2O)) was synthesized and its structure was determined by single crystal X-ray diffraction method. X-ray analysis showed that the compound crystalized in the triclinic system P-1 with a = 7.1134 (3) Å, b = 10.0208 (4) Å, c = 10.3601 (4) Å, α = 96.386 (3)°, β = 96.995 (3)°, γ = 101.219 (4)°, V = 712.05 (5) Å3 and Z = 2 and exhibits that the title compound (I) consists of N′-[(E)-3-pyridinylmethylene]nicotinohydrazide (II) (C12H10N4O), and three water molecules of crystallization. The two water molecules are attached to the third water molecule through intermolecular two OH…O hydrogen bonds. At the same time, this water molecule is linked to the NH amide group of the hydrazone by an intermolecular NH…O hydrogen bond. Hirshfeld surface (HS) analyses were carried out are to visualise the intermolecular interactions in the crystals of Compound I. The geometric optimization of the titled compound has been carried out by different computational methods such as by Hatree Fock (HF) and Density Functional Theory (DFT) methods with the 6–311++G (d,p) basis set. The vibrational frequency, dipole moment (μ), polarizability (α), hyperpolarizability (β), and electronic properties including the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO–LUMO) of the compound have been calculated at the level of both theories. In the results of crystal analysis and geometry calculations of the compound I, it was observed that intermolecular hydrogen bonds, N2H2A…O3, O3H31…O2 and O3H32…O4, were formed. The energy band gap (Eg = ELUMO-EHOMO) values were also obtained by using ELUMO and EHOMO at the level of both theories. The value of equilibrium (ground state) dipole moment of the studied molecule was calculated to be 8.31 Debye in B3LYP and 7.55 Debye in HF. The calculated hyperpolarizability values at the B3LYP/6–311++G(d,p) of the compound are 2.53 × 10−30 esu and this value corresponds to 6.79 times the hyperpolarizability value of urea.

Digital One-Step Competitive Detection of a Small Molecule in Synthetic and Environmental Waters.

Optical methods for single-molecule analysis hold the promise of accurate, sensitive, and rapid detection of target molecules. Here, we demonstrate the efficiency of such an approach for the competitive detection of small molecules in water. Our biosensing method is based on a combination of a single-DNA biochip for the parallelization of tethered particle motion real-time measurements with antibodies and modified targets as molecular competitors. The antibodies are coupled to the particles tethered to the surface by a long DNA bearing in its middle the molecular competitor bound to the antibodies. Competitive target binding leads to a detectable conformational change of the DNA tethers from looped to unlooped in proportions related to the target concentration. We thus managed to detect fluorescein, chosen as a model of a target molecule, in freshwater of various qualities, from solutions prepared with ultrapure water to more complex matrices such as river water and wastewater treatment plant effluent samples. Similar dose-response curves were obtained under these various conditions in a wide range of concentrations from nanomolar to micromolar with a limit of detection around 2 nM.

Consciousness: a quantum optical effect in fluorescent protein pathways

This paper presents a physical mechanism of embodied consciousness based on the dynamic organicity theory. We use the entropic pilot wave theory to describe the quantum dipole oscillations from dipole-bound delocalized (quasi-free) electrons in nonpolar nanocavities of aromatic amino acid residues (benzene moiety /cyclic hydrocarbons that contain resonance structures) and their fluorescent pathways. These pathways contain cavity quasipolariton condensates composed of quantized polarization waves of entangled photons. The behavior of oscillating molecular dipoles is influenced by the quantum nature of dynamic organicity, which causes energy fluctuations necessary to move delocalized electrons and create bare polaritons (quantized polarization waves). These waves correspond to photon quasiparticles interacting with water molecules to form quasipolaritons, softened by interacting with hydroxide ions (OH-) within crystal lattices of interfacial water H30. When [H3O+]=[OH−], the solution is neutral in hydrophobic nanocavities. In such nonpolar cavities, evanescent photons (non-radiative transitions in the absence of any source) are emitted while protons (H+) diffuse due to recombination with hydroxide (OH-) ions, acting as protonic analogs of ‘holes’ or excitons. In protein pores, proton motion strongly coupled with π-electron delocalization is a conduit for exciton-photon (polariton) and its polarization wave component. Internal energy fluctuations comprise both quantum potential energy and negative quantum kinetic energy. We explore how quantum potential energy influences the negentropic effect of a 'repulsive force' guided by entropic pilot waves through pilot wave force (negentropic force), functioning as an information-based action of the polarization wave as a conduit of the cavity quasipolariton. When the rate of change of quantum entropy is zero, and momentum of the polarization wave is zero the internal energy transduction between quantum potential energy to quantum kinetic energy manifests as the negentropic force and facilitates the movement of information-based action for information encoding when negative quantum kinetic energy happens at certain times. Experiments have shown that biphoton entanglement interferes with anaesthetics. We postulate that the disruption of cavity polaritonic condensate through its polarization wave component disrupts the decoding of information, suggesting consciousness is attributed to a quantum optical effect. Therefore, we further theorize that consciousness is attributed to the negative quantum kinetic energy of the polarization wave, which provides an informational structure of multiscale redundancy when negentropic action reduces information redundancy. This has profound implications for understanding consciousness as nonmechanical action channeled through negentropic force when the rate of change of quantum entropy is zero.

Elucidating the Hydrolysis and Polymerization Reactions of Al3+‐Solvated Molecules by Reactive Molecular Dynamics Simulation

ABSTRACTUtilizing the reactive molecular dynamics (ReaxFF MD) simulation, we conducted a comprehensive study on the impact of basicity (OH−/Al3+ ratio), concentration, and temperature on the hydrolysis and polymerization reactions of Al3+‐solvated molecules. Through simulations, we analyzed the structural changes, energy fluctuations of the system, and the evolution patterns of reaction products under different parameters, which were subsequently validated by experimental data. The research results indicate that hydroxide ions in the solution directly influence the breakage of OH bonds in the coordinating water molecules of solvated aluminum ions. This, in turn, affects the number of H2O and OH− ions coordinated with Al3+, leading to changes in hydrolysis products. Additionally, the number of OH− ions surrounding Al3+ affects the electrostatic repulsion, making it easier for polymerization reactions to occur as the system approaches the point of zero charge. On the other hand, an increase in concentration and temperature enhances the frequency of cluster collisions, thus contributing to an increase in polymerization degree. The experimental results align closely with our simulated predictions. As the pH value increases, the particle size exhibits a trend of first increasing and then decreasing, reaching a maximum at the point of zero charge. Simultaneously, an increase in concentration also prompts an increase in particle size. The combination of these empirical results with simulations enhances the credibility and reliability of our model's predictive capabilities. This study not only expands our understanding of the relevant chemical reaction processes but also provides important theoretical support for practical applications in related fields.

Reaction-Free Energies for Complexation of Carbohydrates by Tweezer Diboronic Acids.

The accurate calculation of reaction-free energies (ΔrG°) for diboronic acids and carbohydrates is challenging due to reactant flexibility and strong solute-solvent interactions. In this study, these challenges are addressed with a semiautomatic workflow based on quantum chemistry methods to calculate conformational free energies, generate microsolvated solute structural ensembles, and compute ΔrG°. Workflow parameters were optimized for accuracy and precision while controlling computational costs. We assessed the accuracy by studying three reactions of diboronic acids with glucose and galactose, finding that the conformational entropy contributes significantly (by 3-5 kcal/mol at room temperature). Explicit solvent molecules improve the computed ΔrG° accuracy by about 4 kcal/mol compared to experimental data, though using 13 or more water molecules reduced precision and increased computational overhead. After fine-tuning, the workflow demonstrated remarkable accuracy, with an absolute error of about 2 kcal/mol compared to experimental ΔrG° and an average interquartile range of 2.4 kcal/mol. These results highlight the workflow's potential for designing and screening tweezer-like ligands with tailored selectivity for various carbohydrates.

Simulation of the effects of nanopores at different scales on the wettability of coal

The structural difference of nanopores at different scales in coal is one of the important factors that affect the wettability of coal. Therefore, it is necessary to determine influences of nanopores at different scales in coal on the wettability thereof from the perspective of molecular structure. Taking coal samples collected from Pingdingshan (PDS), Hebi (HB), Xiegou (XG), and Changping (CP) as research objects, the nanopore combination types of the interface were divided by using Materials Studio (MS) molecular simulation software and Image Pro Plus (IPP) image processing software, fractal theory and wettability dynamic simulation method, and the fractal characteristics of different nanopore combination types and the wetting angle change characteristics of active water were analyzed. The effects of total porosity and fractal dimension of pore structure on wettability of nanopores were discussed. The results show that the nanopore combinations in coal can be divided into three types according to the diameter of water molecules: those separately dominated by diffusion pores, adsorption-diffusion pores, and adsorption pores. As the diameter of dominant pores decreases, the fractal dimension decreases and the structure becomes increasingly simple. The wetting angle of active water in diffusion pores changes as follows: it rapidly decreases at first, then tends to stabilizes, before increasing slightly; that in adsorption-diffusion pores changes in this way: it rapidly decreases after transient fluctuations, then basically stabilizes, and finally slightly increases; that in adsorption pores changes as follows: it fluctuates for a long period, then decreases with fluctuations, and finally basically stabilizes. As the total porosity of nanopores increases, the wetting angle decreases linearly. If the porosity is similar, the negative influence of fractal dimension on the wettability of coal interfaces by active water increases as the scale of dominant pores in pore combinations decreases.

Hydrophilicity Dependent Distribution of Water at Ionic Liquids/Metal Interface Monitored by Electrochemical SERS.

The understanding of the interfacial processes is critically important for extending the practical application of ionic liquids, particularly for the role of interfacial water. In the electrochemical system based on ionic liquid electrolytes, small amounts of water at the interface generate a significant change in the electrochemical behaviors of ionic liquids. Therefore, the investigation on the interfacial behavior of water is highly desired in ionic liquids with different anions, water content, and hydrophilicity. Herein, based on the probe strategy, in situ surface enhanced Raman spectroscopy (SERS) combined with electrochemical control (EC-SERS) was developed to investigate the influence of hydrophilicity/hydrophobicity of ionic liquids on the interfacial water. The water-sensitive transformation reaction of 4,4'-dimercaptoazobenzene (DMAB) to para-aminothiophenol (PATP) was employed as a probe reaction for investigating the behavior of interfacial water. The changes of relative SERS intensities of DMAB to PATP served as an indication of the quantity variation of interfacial water. The results show that the transformation reaction efficiencies were critically dependent on the additional water contents, potential, and hydrophilicity of ionic liquids. With a very low molar fraction of additional water (Xw = 0.01), transformation efficiency of DMAB (the amount of interfacial water) followed the sequence of [BMIm]BF4 < [BMIm]PF6 < [BMIm]Tf2N. It was in agreement with the hydrophobicity order of the ionic liquids. With the increase in additional water content, the potential for the full transformation was positively moved, and the efficiency increased significantly. The stronger hydrophobicity allowed more water molecules to migrate to the interface, which was attributed to the difference in interactions between water and the anions of ionic liquids. It demonstrated that the small amount of water tended to gather at the interface in hydrophobic ionic liquids. Compared to traditional cyclic voltammetry, the EC-SERS technique combined with probe reactions is more sensitive to interfacial water. It is anticipated to develop as a promising tool for the investigating water-related issues at interfaces and to provide guidance to screen ionic liquids for practical application.

Multifunctional and Ultrastable Co-MOF Effectively Separates Various Different Component Gas Mixtures.

Developing low-cost and multifunctional adsorbents for adsorption separation to obtain high-purity (>99.9%) gases is intriguing yet challenging. Notably, the ongoing trade-off between adsorption capacity and selectivity in separating multicomponent mixed gases still persists as a pressing scientific challenge requiring urgent attention. Herein, the ultrastable TJT-100 exhibits unique structural characteristics including uncoordinated carboxylate oxygen atoms, coordinated water molecules directed toward the pore surface, and sufficient Me2NH2+ cations in channels. TJT-100 exhibits a high adsorption capacity and exceptional separation performance, particularly notable for its high C2H2 capacity of 127.7 cm3/g and remarkable C2H2 selectivity over CO2 (5.4) and CH4 (19.8), which makes it a standout material for various separation applications. In a breakthrough experiment with a C2H2/CO2 mixture (v/v = 50/50), TJT-100 achieved a record-high C2H2 productivity of 69.33 L/kg with a purity of 99.9%. Additionally, TJT-100 demonstrates its effectiveness in separating CO2 from natural gas and flue gas. Its exceptional selectivity for CO2/CH4 (10.7) and CO2/N2 (11.9) results in a high CO2 productivity of 21.23 and 22.93 L/kg with 99.9% purity from CO2/CH4 (v/v = 50/50) and CO2/N2 (v/v = 15/85) mixtures, respectively.

Investigation of the crystal structure, spectral properties, and interactions of N-(R-nitrophenylsulfonamido)benzoic acids with human serum albumin

This study introduced the synthesis of two novel compounds in the N-(R-nitrophenylsulfonamido)benzoic acids (NO2-SBA), designated as HL6 and HL8. Detailed structural information for HL6 and HL8 was acquired through the employment of various characterization techniques such as single-crystal and powder X-ray diffraction, FT-IR spectroscopy, 1H and 13C NMR spectroscopy, and elemental analysis. X-ray diffraction and Hirshfield surface analysis provides a comparative analysis of hydrogen bonding in HL6·H2O and HL8, revealing significant differences in their interaction patterns and resulting crystal structures. Although both molecules possess the same number of hydrogen bond donors and acceptors, the nature of these interactions and their orientations lead to distinct packing arrangements. In HL6·H₂O, the presence of water molecules introduces additional hydrogen bonding possibilities, which are absent in HL8, significantly affecting the overall structure. Additionally, interactions of all nine compounds in the NO2-SBA series [categorized as o-ABA: HL1–HL3, m-ABA: HL4–HL6, and p-ABA: HL7–HL9] with human serum albumin (HSA) were investigated to understand how structural characteristics influence binding mechanisms and affinity. Fluorescence spectroscopy was employed to further examine these interactions, providing a better understanding of their pharmacological properties. The compounds exhibited moderate affinity to HSA, with the o-ABA series displaying a binding constant (Kb) ten times stronger than the other series, underscoring the significant role of the N,R groups in binding interactions.

Fluoropolymer-Gadolinium(III) Hybrids for Photoactivatable Dual-Mode T1-Weighted 1H MRI and 19F MRI Contrast Agents.

Multimodal imaging probes play a crucial role in overcoming the limitations associated with single-mode imaging for clinical medical diagnosis. This study focuses on the development of a photoresponsive fluorine-containing water-soluble polymer (PF) through RAFT polymerization. Subsequently, a polymer-gadolinium(III) hybrid (PF-Gd) dual-modal probe capable of T1-weighted 1H MRI and 19F MRI was synthesized via postmodification of PF with a Gd-DOTA derivative. Under physiological conditions (pH = 7.4), the hybrids exhibit UV-activated 19F NMR/MRI and enhanced 1H MRI. The inclusion of Gd3+ facilitates the acceleration of water molecule T1 relaxation, leading to high-intensity 1H MRI contrast. Leveraging the paramagnetic relaxation enhancement (PRE) effect between fluorine atoms and Gd3+, the restoration of Gd3+-accelerated 19F T2 relaxation enables precise photoactivation of 19F MRI signals, transitioning from the "OFF" to the "ON" state. This study provides an important reference for the development of hybrid systems that function as real-time diagnostic tools and offers controlled activation for multimodal imaging probes.

Poly(butylene 2,5-thiophenedicarboxylate-co-glycolate) copolyesters with good degradation and barrier properties

In this work, poly(butylene 2,5-thiophenedicarboxylate-co-glycolate) (PBTFGA) copolyesters were synthesized from 2,5-thiophenedicarboxylic acid, 1,4-butanediol and glycolic acid. The influence of the glycolic acid content on thermal properties, mechanical properties and degradation capacity of copolyesters was systematically investigated. The glass transition temperature of copolyesters closely matched that of poly(butylene 2,5-thiophenedicarboxylate) (PBTF). While also demonstrating good thermal stability. When the glycolic acid content was low, the copolyesters exhibited some crystallization capability, but they gradually became fully amorphous as the glycolic acid content increased. The tensile tests revealed that the young's modulus of the PBTFGA copolyesters ranged from 69.2 MPa to 221.4 MPa. With elongation at break exceeding 659%, outperforming most biodegradable packaging materials. Copolyesters exhibited excellent gas barrier properties to both oxygen (PO2 = 0.024 barrer) and carbon dioxide (PCO2 = 0.029 barrer), both of which are superior to poly(butylene 2,5-thiophenedicarboxylate). The incorporation of glycolic acid significantly reduced the crystalline content of the copolyesters, facilitating the interaction of water molecules with ester bonds in the polymer backbone. The weight of poly(butylene 2,5-thiophenedicarboxylate-co-glycolate) was decreased significantly during enzymatic hydrolysis, indicating excellent degradation performance

Neurite Orientation Dispersion and Density Imaging (NODDI) reveals white matter microstructural changes in Obstructive Sleep Apnea Hypopnea Syndrome (OSAHS) patients with cognitive impairment

PurposeThis study aimed to assess changes in white matter microstructure among patients undergoing obstructive sleep apnea hypopnea syndrome (OSAHS) complicated by cognitive impairment through neurite orientation dispersion and density imaging (NODDI), and evaluate the relationship to cognitive impairment as well as the diagnostic performance in early intervention. MethodsTotally 23 OSAHS patients, 43 OSAHS patients complicated by cognitive impairment, and 15 healthy controls were enrolled in OSA, OSACI and HC groups of this work. NODDI toolbox and FMRIB's Software Library (FSL) were used to calculate neurite density index (NDI), Fractional anisotropy (FA), volume fraction of isotropic water molecules (Viso), and orientation dispersion index (ODI). Tract-based spatial statistics (TBSS) were carried out to examine the above metrics with one-way ANOVA. This study explored the correlations of the above metrics with mini-mental state examination (MMSE), and montreal cognitive assessment (MoCA) scores. Furthermore, receiver operating characteristic (ROC) curves were plotted. Meanwhile, area under curve (AUC) values were calculated to evaluate the diagnostic performance of the above metrics. ResultsNDI, ODI, Viso, and FA were significantly different among different brain white matter regions, among which, difference in NDI showed the greatest statistical significance. In comparison with HC group, OSA group had reduced NDI and ODI, whereas elevated Viso levels. Conversely, compared to the OSA group, the OSACI group displayed a slight increase in NDI and ODI values, which remained lower than HC group, viso values continued to rise. Post-hoc analysis highlighted significant differences in these metrics, except for FA, which showed no notable changes or correlations with neuropsychological tests. ROC analysis confirmed the diagnostic efficacy of NDI, ODI, and Viso with AUCs of 0.6908, 0.6626, and 0.6363, respectively, whereas FA's AUC of 0.5042, indicating insufficient diagnostic efficacy. ConclusionsThis study confirmed that NODDI effectively reveals microstructural changes in white matter of OSAHS patients with cognitive impairment, providing neuroimaging evidence for early clinical diagnosis and intervention.

Synthesis and properties of oligopropylamines with photosensitive o-nitrobenzyl ester core

The o-nitrobenzyl ester group is known for more than 50 years as a convenient protecting group and fragment for the design of photosensitive systems, including drug delivery agents. Polymeric amines with these groups are promising systems for medical applications, but the lack of basic knowledge about the possible degradation of these compounds under physiological conditions restrains the development of real preparations. We synthesized five new polyamines with the insertion of the o-nitrobenzyl ester group into the chain, including an oligomeric mixture with a weight average number of amine groups equal to 21. The ester group in the polyamine chain was found to be sensitive to hydrolysis at neutral and alkaline pH values. The presence of an amine group near the ester group facilitates hydrolysis through coordination with a hydroxyl ion or water molecule. The catalytic action of the amine moieties is prevented by protonation of the amine at low pH values or by interaction with polymeric acid. The study of photodegradation of new polyamines by HPLC-MS showed the formation of a number of products, most of which were not considered in previous works with o-nitrobenzyl ester derivatives. The o-nitrobenzyl ester group is used in the design of gene delivery systems and other biomedical preparations as a fragment that can be degraded by light. Our results indicate that photodegradation of o-nitrobenzyl esters can produce a number of compounds whose structure and safety for living organisms must be evaluated before use. On the other hand, the discovered hydrolyzability of o-nitrobenzyl esters catalyzed by a neighboring amine group may find application in the development of drug delivery systems. We have shown that the lifetime of o-nitrobenzyl ester containing polyamines is sufficient for gene delivery. Self-degradation of the delivery agent after penetration into a living cell is a desirable case for the release of the delivered agent.

Temperature self-compensated dual core fiber-optic sensor integrated with moisture sensitive MIL-96(Al) film for breath detection

In this paper, a dual-core fiber optic sensor has been proposed for dynamic monitoring of temperature and humidity. The side core is polished into a D-type optical fiber, and a layer of nano-silver film and a layer of polydimethylsiloxane (PDMS) are deposited to construct a surface plasmon resonance (SPR) temperature compensator. The middle core is constructed as the long-period fiber grating (LPFG) sensing channel. The mode conversion of LPFG is achieved by TiO2 film, and its refractive index (RI) sensitivity is increased by about 4 times. Meanwhile, a layer of moisture sensitive MIL-96(Al) film is grown outside the TiO2 film. Due to the particular pore structure for water molecules, it is possible to change the effective RI of MIL-96(Al) film by absorbing water molecules. Research has shown that the LPFG sensor can achieve a relative humidity sensitivity of −0.411 nm/%RH. Finally, the sensor successfully achieved real-time dynamic monitoring of respiratory rate.